(116) Cooper 1962 Biochemical Aspects of Methano Poisoning

8/12/2019 (116) Cooper 1962 Biochemical Aspects of Methano Poisoning

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BIOCHEMICAL ASPECTS OF METHANOL POISONING Jru j r ^^

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JACK R. CooPt and MOHANDA S M. K NI IA,C

Department of Pharmacology, Yale University School of Medicine, ^New Haven, Conn., U.S.A.

/ C (Received 2 March 1962; accepted 9 M arch 1962) /^ t

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INTRODUCTION

O, .

PolsoNiNG from methyl alcohol (wood alcohol) has been known sincp 1856, butdespite an extensive literature on the subject (by 1904, 275 cases of blindness or r,),death attributable to methanol had been reported), this toxic solvent was still beingused in the early part o f the twentieth century as a substitute for grain alcohol (ethyl Lialcohol)in liniments, toilet a rt icles, perfumes, and patent medicines ." $ Even Panl 's t Êhrlich was using meth y l alcohol as a solvent for ar henamine in 1914. Although ; }

most of the cases of poisoning resulted from ingestion of methylated spirits, toxic N Aeffects attributable to inhalation or absorption through the skin were well documented;for example, Browns described the case of a factory worker who spilled a gallon of w 0 U_I 1 ^methanol down his trouser leg, was dizzy on the following day, took a short nap,and woke uptotally blin d.

Despite the numerous reports of individual toxic responses to m ethanol, a survey of jGr_the imm ense literature on the subject reveals a high incidence of poisoning in epidemicV 1form, generally resulting from the sale of bootleg liquor. Thus, for example, in oneperiod of 7 months, during the years when the sale of spirits was prohibited in thebiusea states, there were 400 fata lities. A series of 323 cases of m ethanol poisoning resulted from the ingestion of adulterated liquor, which occurred in the area of At- p 'ylanta, Georgia, was described in l953. During war time, servicemen are prone to

V r`f rPa BLSdrink wha tever alcohol is available, without regard to the length of the carbon cha in, Oh 05 ^ and the results of thispractice are evident in the estimate that 6 r cent of all casesof blindness in the Armed Forces during World W ar if was caused by methanol .

6 f f It should be noted that this figure takes into account on ly nonfatal cases; consid ers - '

tion of the number of deaths that resulted from methanol would considerably enlargeI. I C ` " ihis statistic. I

CLINICAL CHARACTERISTICS OF METHANOL INTOXICATION

The clinical course in methanol toxicity in man is characterized both bya marke dvariation in response to size of dose a nd by an asymptomatic latent period between

This article is one of a series of editorials to be published by this Journal to deal critically withcurrent trends in special areas of biochemical pharmacology. The function of such Editorials is to yd ({ i 1summarize the present position, and to indicate potentially profitably lines of investigation. a C ât Senior Research Fellow of the United States Public Health Se rv ice. {

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406 3Acsc R. COOPER and MoHANDA.c M. Kn.n

the ingestion of methanol and the onset of manifestations of poisoning. Ingestion of from 70 to 100 ml of methanol is usually fatal although cases are listed in the literaturein which the consumption of 540 ml did not result in the development of any irrever-

sible manifestations of toxicity.' On the other hand, Duke-Elder" has cited instances inwhich a teaspoonful of methanol caused blindness, and about 30 ml was lethal.

yt Within 2 hours, or even as late as 72 hours, after ingestion of the methylated spirit,the patient becomes fatigued, and experiences such signs and symptoms as headache,

h

dizziness, nausea, and moderate gastrointestinal distress , generally followed by_yxsuaLdisturbances. In more severe cases, intense upper abdominal pains are manifest,weakness develops, and the patient usually is comatose upon admission to hospital,with increased reflex hyperexcitability and even convulsions. Respiration may be rapidand shallow, or of the Kussmaul type, as in diabetic coma. The patient may have alowered blood pressure, and if dyspnea and cyanosis are present, the prognosis isdoubtful.

The most significant laboratory finding is the occurrence of a severe metabolicacidosis as determined by the CO

2-combining power of the blood, which falls to lessthan 20 volumes per 100 ml; only one record of measurement of blood pH has beenfound in the literature of methanol poisoning: a pH value of 7 . 08 was found. ,

Retinal changes are characteristic of methanol poisoning. Total bilateral blindnessmay develop after a few hours or may be delayed by a few days. Observation soonafter the onset of visual disturbances reveals considerable retinal edema; there may bepapillitis with swelling and dilation of veins and some diminution of the pupillarylight reflex. The degree of impairment may be of prognostic value, for most patientswith fixed and dilated pupils succumb. 1 A dense central or paracentral scotoma usuallydevelops an d may precede retrobulbar neuritis or optic atrop hy. Other ocular ab-normalities noted by Duke-Elder 8 include pt osis, paresis of extraocular muscles , andan excavation of discs that results in deep glaucomatous cuppin g, despite the absenceof elevated intraocular tension; residual ocular defects persist in up to 50 per cent of

the nonfatal cases.In summary, it is emphasized that ophthalmoscopically visualized changes, such as

retinal edema and pupillary dilation, associated with delirium, coma, and severe ab-dominal pain, together with a lowering of the COs-combining power of the blood,are characteristic of methanol poisoning. Death usually occurs in inspiratory apneaas a result of failure of the respirator y center that is associated with severe damage tothe central nervous syste m.

Pathology

The findings at autopsy in fatal cases of methanol poisoning have been describedby various authors,s''.

11-13these include variable cerebral edema and e e i

edematous lungs conge sted with patchy atelectasis, and petechial hemorrhages.Additional changes, although these are not pathognomonic of methanol poisoning,are gastritis, epicardial hemorrhages, mild fatty infiltration of the liver, cloud yswelling in the cells of the spinal cord, and congestion of the glomerular tufts an dcloudy swelling of the convoluted tubules of the kidneys. The b ronchial passages maycontain fro y debris, and sometimes desquamation of the br onchial epitheliumoccurs. Pancreatic necrosis, observed by Bennett et a!. 5 in cases of methanol poisoning,has been attributed to generalized vascular injury and hemorrhage.

Bioc

The significance of the paththe eye have been the subjectsby MacDonald," in which cartissues, the retinal changes wercystic spaces in the layer of garod and cone nuclei, migratiovessels. Much earlier, Pick andganglion cell layer. Recent stuglion cells and associated eccewere observed in the optic nervgliosis.k1. 1$, 17

A bsorption and excretionThe gastrointestinal tract i

though, as previously mentione

inhalation or absorption throutissues, in proportion to their gastrointestinal tract, and the analyzed in these experimentspoisoning, Bennett et a!. 5spinal fluid, as compared withper cent is eliminated unchandogs and rabbits, approximateladdition to excretion of methanis secreted into the gastric juin the blood, even I0 days aftlavage may be a useful adjunct

MetabolismA large part of the ingested

is oxidized to formic acid; the ]to carbon dioxide and water. Twith respect to the contributioThe experiments of Lund' incretion of formic acid after thtube, whereas Bastrup' 2 obexcreted as formic acid. In dogstrated that up to 20 per centformic acid. The excretion of fwithin 24 hours, the amount elias 5 per cent of the methanol iblood and urinary levels of forof methanol.

As indicated previously, the organism proceeds through the

the production of formaldeh


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Biochemical aspects of methanol poisoning 40 7

The significance of the pathological charges and the site of the primary lesion inthe eye have been the subjects of considerable controversy. In the fatal cases describedby MacDonald, 14 in which care was taken to ensure prompt fixation of the oculartissues, the retinal changes were characterized b y markefi rinannPrsr:., o..hn.,, ......M..

rod and cone nuclei, migration of pigment granules and congestion of choroidalvessels. Much earlier, Pick and Bielschowsky ls had noted histological changes in thegan ion cell layer. Recent studies have confirmed the cystic degeneration of the gan-glion cells and associated eccentric placement of nuclei and tigrolysis, but few changeswere observed in the optic nerves, except for edema and hyperemia with associated$liosis.u" 16, 17

4

" Absorption and excretion

olicThe gastrointestinal tract is the most common route of entry of methanol, al-

less though, as previously mentioned, the literature includes reports of poisonings fromeen inhalation or absorption through the skin. Methanol is distributed uniformly in

tissues, in proportion to their water content, and is highest in muscles, blood, theness gastrointestinal tract, and the liver, in that order; 1s ,

10cerebrospinal fluid was not

analyzed in these experiments, which were done on dogs and rats. In clinical cases of on poisoning, Bennett el al. 5 have observed consistently higher levels in the cerebro-y bespinal fluid, as compared with those in the blood. Of methanol ingested, up to 50aryper cent is eliminated unchanged through the Iungs

,40 and, in experiments withnts - dogs and rabbits, a pp roximatel y 1ally

addition to excretion of methanol through the pulmonary and renal routes, methanolb-is secreted into the gastric juice in concentrations five to twelve times greater thanndin the bloo d, even 10 days after oisonin ;& this circumstance suggests that gastricncelavage may be a useful adjunct to therapy.

M etabolismA large part of the ingested methanol is oxidized to formaldehyde, and this, in turn,

is oxidized to formic acid; the latter is either excreted in the urine or further oxidizedto carbon dioxide and water. There is considerable variation among animal specieswith respect to the contribution of renal excretion to the elimination of formic acid.The experiments of Lund 21 in rabbits, showed only a slight increase in urinary ex-cretion of formic acid after the administration of methanol through an esophagealtube, whereas Bastrup 22 observed that up to 8 per cent of ingested methanol may beexcreted as formic acid. In dogs, however, Lund and Bastrup independently demon-strated that up to 20 per cent of the methanol administered could be excreted as

formic acid. The excretion of formic acid in man follows an intermediate course and ,within 24 hours, the amount eliminated by the kidneys may be equivalent toasjmtchhaste r cent of themethanoljngt' . 23 In all these experiments, however, maximalblood and urinary levels of formic acid were reached from 2 to 3 days after ingestionof methanol .As indicated previously, the formation of formic acid from methanol in the animalorganism proceeds through the intermediate formation of formaldeh y de. Althoughthe production of formaldehyd e from methanol by liver tissue can be readily

L i


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408 JxcK R. CooPan and Mow s M. Km i Bioch

attempts by various workers ss " EBto isolate formaldehyde from

is attributable to the raid reaction of formaldehyde with the tissue proteins ; u on

the other hand, Keeser8e

found demonstrable amounts of formaldehyde in the vitreoushumor of the s eye and Benton and oun have reported the presence of a"trace of formaldehyde" in the vitreous humor of one patient who died after poison.ing with methanol. These reports must await further substantiation before it can beconcluded unequivocally that formaldehyde can be isolated from tissues in clinicalcases of methanol poisoning.

The mechanism of oxidation of methanol to formaldehyde is a subject of muchlively debate. Lutwak-Mann ar obse rved that partially purified alcohol dehydrogenasefrom horse liver could catalyze the oxidation of methanol to formaldehyde, an ob-servation confirmed by Zatman, B who found that ethanol competitively inhibited thisreaction. The crystalline enzyme however, was found to be incapable of promotingthis reaction. 81 - 33 These observations led to the postulate that methanol is oxidizedto formaldehyde by a peroxidative mechanism mediated by catalase and a hydrogenperoxide-generating system such as hypoxanthine and xantltine oxidase. According toChance, the kinetics of the disappearance of methanol from the blood of rabbitsagreed with such a postulate.

8 Using the undefined system, Tephly et al. foundthat

methanol from the blood of rats to w hich the alcohol had been administered.In this laboratory we have recently investigated this problem with material from

monkeys, since it has been firmly established that a unique type of methanol poisoningoccurs in primates. TM' $' We found that the ratio of the rate of oxidation of methanol,as compared with that of ethanol, remained almost constant over a 90-fold range of purification of an enzyme system isolated from the liver of the rhesus monkey.Ethanol competitively inhibited the oxidation of methano l. The enzyme was subse-quently crystallized from horse liver. From this information, as well as studies withinhibitors, it was concluded that the enzyme involved is alcohol dehydrogenase.Studies on the rate of elimination of methanol in the blood of monkeys given methanolby intubation agreed with its rate of oxidation as observed in vitro. All these observa-tions led Kini and Coomer" to conclude that it is alcohol dehydrogenase, and not thecatalase system, that is responsible for the physiological oxidation of methanol.The inability of previous investigators to show that methanol is a substrate forcrystalline liver alcohol dehydrogenase is attributab le to the low concentration of methanol used in their experiments. The Km for methanol is about 1 . 7 x 102 M. butmost of these previous workers employed the alcohol at a level of about 1 x 14 - 3 M .A]Tiwugti itis unnecessary, at the present time, to invoke the participation of the cata-lase system in the oxidation of methanol, the experiments of Kini and Cooper do not

exclude the participation of this mechanism. It is possible that, with low levels of methanol in the body, the peroxidative action of catalase caul eAt least seven different enzymes capable of catalyzing the conversion of formalde-

hyde to formate are present in a - aldehyde dehydrogenase, xanthineoxidase, glyceraldehyde -3-phosphate dehydrogenase, catalase, peroxidase, and alde-hyde oxidase; in addition, Strittmatter and Ball B have obtained from extracts of beef

and chicken liver a specific quires glutathione as an addbeen demonstrated in bovin

formaldehyde in the body is that acts on the retina is actuaoccurs in the retina and apparA alcohol to retinene.91

Although, as mentioned eaoxidized to carbon dioxide shown recently to involve thegenerating system 42

TreatmentThe rationale for the treatm

of the metabolism of methaGastric lavage, using either sin the early stages of poisonitoms and signs. Elimination dialysis has been successfullydialysis has been successfullyeffective in withdrawing ureearly and massive administra(500 ml of a 5% solution) ; sthe bicarbonate and pH levhypokalemia or tetanic conv

The use of the simultaneoutreatment in methanol toxipatients who imbibed ethan

from the toxic effects of thml of blood is recommendedosis. This form of therapyan ounce of whiskey everyAlthough it has been shownincreasing its excretion in rthat administration of ethannervous system in an alreadthis reason.

The tox ic agent in methanol It is now generally accept

proximal toxic agent in methof a characteristic latent pepoisoning; (ii} the beneficanimals and clinical cases omaldehyde is inhibited; and toxicity of formaldehyde to


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410 _ . JAcx R. COOPER and MOHArmAs M. Kim Bio

study of the t oxicity of methanol, formaldehyde, and sodium formate on bovin e In addition, acidosis, anotretinal homogenates In vitro , Pott s and Johnson have found formaldehy de to be the is not present in experimemost toxic to reil gl yco ysisiration !

s their studies we re confirmed by The reason for this pecu

Leaf and ,Zatman.47

Praglin et al.40

extended these investigations by examining the methanol is still unknown.effects of this series of compounds on the electroretinogram (ERG) of monkeys and and in a recent investigatiofound that a concentration of formaldehyde, which approximates that reasona bly with glycolysis and the hassumed to be present in methanol poisoning (0 .0007 mole / kg of body weight), differences were noted betwproduced by intravenous administration, abolished th e b-wave of the ERG, while thi from the monkey. Thus, awas affected by formate and methanol only at 0 .025 and 0 .03 mole /kg.. respectively, methanol intoxication mayAcetaldehyde did not affect the ERG in doses 50 times higher than the effective dose the retina (vide infra), thesof formaldehyde. A detailed study by Kini and Cooper" on the effects of methanol in methanol poisoning; thand its metabolites on the bovine retina in vitro have essentially confirmed the observa . contribute to an explanatitions of Potts and Johnson; in addition, Kini et a!. 51 found that formaldehyde, ad- One of the possibilities ministered to rabbits intraocularly in order to avoid the principal sites of m etabolic hyde is different in these twalteration, affected both the morphology of the retina and t e enosine tripfiosphate of methanol to formaldeh

hyde is rapid. Thus, the co(ATP) production, as inferred from the incorporation of P- labeled inorganic hos-phate into phospholipids. In contrast, neither methanol nor sodium formate had any would be too low to causeeffect on the labeling of phospholipids or on the histology of the retina (aide infra). rapidly from methanol by

From all these obse rvations the conclusion is almost inesca ab le that the toxi c slow; thus, formaldehydeagent to methanol poisoning is formaldehyd e. It should be pointed out, however, that that its inhibitory prope rthe ingestion of large amounts of methanol will give rise to manifestations that can that bear on this hypothesmost correctly be ascribed to a nonspeci fic narcotic effect of the alcohol itself, an intoxication, metabolic aceffect seen with the intake of many alcohols. with the liver being the tis

Species difference A second possibility tha

One of the major stumbling blocks in the elucidation of the biochemical eventsan anatomical consideratguinea pig are essentially

that occur in methanol poisoning was the inability of earlier investigators to discern cordingly, it is vabconceivablconceithe difference between laboratory animals and humans in their response to methanol retinal cells of the

ingestion. It was primarily due to Roe," and subsequently to Gil er and Potts, S7 that

reason not yet evident, thethe effect of methanol on nonprimates was attributed to a narcotic effect similar to could be much greater thathat seen with various alcohols and comnletel y different from the effect seen in primatesnamely, the production of blindness and of metabolic acidosis.

A critical evaluation of the extensive literature of the histopathological changes in The metabolic lesion in b ndnes.the eyes of laboratory animals poisoned with methanol is beyond the scope of this Despite the large numbreview. Many of the changes described in the earlier work on the histology of the noted in the introduction, nretinas of methanol-poisoned animals could not be obtained by Friedenwald 5P or retinal metabolism has beby de Schweinitz, 53 Friedenwald regarded these earlier findings as artifacts of fixation recent times both Potts andand embedding. Subsequent investigations by Alder et al. 6 and Roes who work ed inhibitory prope rt ies of f% yi h rats and rabbits, and by Potts et al.' 5 and Cooper and Felig, 66 who worked with group has proffered a hypo

' L rhesus monkeys, have failed to demonstrate histological changes in the retina analo- by the administration of mgous to those seen in clinical cases of methanol poisoning. Potts an co-wor ers In this laboratory our i

observed cy

st formation in the external nuclear lay

er, edema, and nuclear py

knosis in methanol poisoning was bthe putamen and caudate nucleus, but saw no other major change in these methanol- the generation of ATP, a cpoisoned monkeys, despite marked edem a ophthalmoscopicallyobserve d and altera- process; the resultant deftion in the electro retmoaram. In conclusion, it appears that any histological changes of certain retinal cells, wiseen in the retinas of nonprimate species of animals a re att ributable to the narcotic "easy virtue" of interfereeffect of toxic doses of methanol and differs from the changes characteristic of man. action, and of the fact tha


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Biochemical aspects of methanol poisoning 41 1

ne In addition, acidosis, another common manifestation of methanol poisoning in man,

e is not present in experi mental animals, with the exception of the monkey.67

y The reason for this peculiar species difference in the response to the ingestion of he E methanol is still unknown. In studies in our laboratory on oxidative phospho rylation,d and in a recent investigation by Lowry et aL 58 on the activity of enzymes associatedy with glycolysis and the hexose monophosphate shunt, no significant biochemical), differences were noted between retinas obtained from nonprimates and those obtaineds from the monkey. Thus, although the biochemical lesion in blindness attributable toly, methanol intoxication may be ascri bed to an inhibition of ATP-generating systems inse the retina(vide infra), these systems do not appear to account for the species differenceol in methanol poisoning; there are, however, at least three possible factors that could

a- contribute to an explanation of this curious phenomenon.d- One of the possibilities that must be considered is that the metabolism of formalde-olic hyde is different in these two groups. It may be that in the nonprimate retina, oxidationate of methanol to formaldehyde is very slow, and the further_ metabolism of f ormalde-s- hyde is rapid. Thus, the concentration of formaldehyde in the retina at any one timeny wu l d be too low to cause damage. In contrast, formaldehyde may be generated). rapidly from methanol by the p rimate retina, but its subsequent elimination may bec f ' slow; thus, formaldehyde could achieve a concentration high enough per unit time

at that its inhibitory properties could be exerted. Unfortunately, no data are availablean that bear on this hypothesis. With respect to the second striking sign of methanolan intoxication, metabolic acidosis, the same hypothesis outlined above may apply,

with the liver being the tissue of paramount importance.A second possibility that could be involved in the species difference is referable to

an anatomical consideration. It is well known that the retina of the rabbit and the 7\ guinea pig are essentially avascular, in contrast to that of man and monkey " s Ac-

erncording it is conceivable that the toxic agent may have difficulty in reaching thenol retinal cells of the nonp rimate. A third possibility to be considered is that, for some

hat reason not yet evident, the sensitivity of the retinal cells of primates to formaldehydeo could be much greater than that of nonprimates.es

s in The m etabolic lesion in blindnessis Despite the large number of case reports and studies of methanol poisoning, ashe noted in the introduction, no theo ry that is compatible with present knowledge of or retinal metabolism has been offe re d to account for the retinal damage. Although inion recent times both Potts and Johnson" and Leaf and Zatman" have obse rved theked inhibitory prope rt ies of formaldehyde on retinal respiration and glycolysis, neitherwith group has proffered a hypothesis that explains the mechanism of the blindness caused

o-by the administration of methanol.

ers In this laborato ry our initial hypothesis relating to metabolic lesion in the eye tos in methanol poisoning was based on the premise that formaldehyde interferes with

ol- the generation of ATP, a compound assumed to be intimately related to the visualrs- process; the resultant deficiency of this compound would then lead to a degenerationel ofcertain retinal cells, with blindness as the end result. The authors a re aware of thetic "easy virtue" of interference with ATP-generation as a hypothesis to explain dru gan. action, and of the fact that in eve ry case in mammalian tissues in which the detailed

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Bioche412 JACK R. COOPER and MoIArrons M. KtNI

biochemical mechanism of action of a drug is known (e.g., physostygmine, tetra-ethylthiuram disulfide (Antabuse), acetazolamide) the inhibited enzyme system maybe classed as an "accesso ry" enzyme, rather than one involved in energy production.

Nevertheless, in this situation we feel justified in asserting this thesis. After working forover two years on the problem we have yet to encounter any evidence to negate thishypothesis; indeed, much evidence to suppo rt it has been amassed.

If the criteria of Welch and Bueding8 or Lowry and Hunter" are adopted, to demon-

strate that an effect of a drug in vitro fully accounts for the situation in vivo, we can atleast assess the reasonableness of our hypothesis.

With respect to the concentration of formaldehyde used in our experiments, wenever exceeded the concentration of the agent that one might reasonably find in a

i

typical case of methanol poisoning Thus, the in gestion of 100 ml of methanol isgenerally considered to be toxic; if an even distribution of the alcohol in the body beassumed, and in the usual 70-kg man, the maximal con centration of formaldehydethat could be derived from t he methanol would be 0

.04 M . In our experiments invit ro we were impressed with the results that were obtained at concentrations of frnmaldehyde of only 002 M. These concentrations are not only wellwithin the maximal expected level in body tissues, including the retina, but also arecompatible with the level of formaldehyde that could be expected in a reported indi-vidual who drank 4 ml of methanol, with ensuing loss of vision." In experiments invivo in which formaldehyde was injected directly into the eye, it was necessary (forreasons to be discussed below) to produce higher concentrations of the agent, 0.01to 0 .02 M but, from a pharmacological standpoint, these concentrations are stillreasonable.

Using intact retina or mitochondria prepared from beef, we have studied the effectof formaldehyde on glycolysis, respiration, the conversion of "C-glucose to 14CO2,the incorporation of 52P-phosphate into retinal phospholipids, oxidative phorphoryla-

ht y ^ ` r tion, and electron transpo rt .

Although

in intact retina an inhibition of 50% of anaerobic 1 col sis was observedat the low concentration of formaldehyde of 0 .0005 M, it is difficult to assess thisfinding, in view of the vital dependence oflh1e retina on oxygen, with the probabilitythat anaerobiosis does not exist in the normal retina. In contrast, formaldehyde inconcentrations of 0 .0005-0 .005 M did not inhibit aerobic glycolysi s, but actually

roduced a slight stimulation of this rocess." D Both Potts and Johnson's and Leaf and

Zatman 7 have shown that formaldehyde inhibits glycolysis in retinal homogenates.These studies were confirmed and extended by Cooper and Marchesi," an d hexok inase was implicated as the sensitive enzyme in the glycolytic chain; mo re recent studiesby Kini and Cooper," however, have failed to demonstrate an effect of formaldehydewhen testing up to a level of 0 .01 M. The reason for these conflicting results is not yetapparent; it may be that, since hexokinase is in a pa rt iculate form in the retinal homo-genate, the kinetics of this enzyme and of glycolysis may be dependent upon a critical

factor in the preparation of the homogenate.In intact cells, respiration, as measured by oxygen uptake or by the conversion of "C-glucose to "CO,, was not especially sensitive to inhibition by formaldehyde,nor was electron transpo rt in retinal mitochondrial preparations.

The most striking finding observed in our laborato ry is the marked sensitivity of oxidative phosphorylation in the retinal mitochondria to the toxic agent. At a

concentration of 0 .0005-0 .00

by more than 50 per cent when Pas a substrate. By way of control.

0.

005 M, had no effect. The interehyde at low concentrations uncchondria, formaldehyde was actmitochondr ia prepared from liSimilar results were obtained wiis a rare example of a qualitativetissues.

Although the inhibition of ceffected by pharmacological co,inhibition is not merely a nonspehibition of acetaldehyde on thiseffect in vitro truly reflects evcan uncouple oxidative phosph

demonstrated that the pharmacoruption of oxidative phosphoryoxidative phosphorylation in inby an indirect approach. The metion of 'P-labeled inorganic phdependent upon oxidative phosthat formaldehyde, at a level in poration of S'P into phospholienergy production in whole reti

In order to demonstrate this eand 'P-phosphate were injectedthe toxic agent in the eye was a24 hours later and the retinas wa 50 per cent inhibition of the maldehyde-injected eyes, as co

jected with' 2P-phosphate aloassess the effect of the formaldAt a concentration of 0 .0formation in inner nuclear and iand swelling and edema of thecould be seen on occasion wistrikingly similar to changes omethanol poisoning. In these exor acetaldehyde, when tested significant effect either on the

on the histology of the retinas' hyde required in vivo, as cnonspecific binding of this reathe actual concentration of formthat estimated without takinconceivable that some of the f

l fieff l61)


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Biochemical aspects of methanol poisoning 415

modern biochemical knowledge. Definite answers are still to be obtained to the gnes-bons of the long latent period before the onset of symptoms, the nature of the organicacid or acids that are responsible for the metabolic acidosis, and the reason for thecurious species difference that is observed in this poisoning. It is unfortunate that

# most of these problems canbe solved onl with the use of human mate rial after

exposure to this toxic agent that produces such unusu al and ^e

lesions.

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T, J. biol. Ch r ii

invest . ,

8022 .(19^)

43. J. MAIC-AURELE and G. E. S te, J.


12/12

THE DISTRIBRADIOACTIV

OF 31S -LAB

S. SYMCHOWiCZ, W. D. I

Division of Biologi

(Rece

Abstract HS-perphenazine tand radiochemical purity o'excretion of radioactivity

ofs S-labeled perphenaz

+ of r adioact ivitywere found'concentrations were lungparts had somewhat lowlow. High levels of radioremained relatively high during a period of 24 hr; m20 per cent could be foundday 19 of pregnancy sh24 hr, however, the concextremely low.

THE widespread use of incrus to examine in detail the mmember of this class of commeans of a careful study emformation could be gained metabolism, mode of actiowill concern itself with the perphenazine in body tissuetion of the drug, and the mowith the chemical form in urine.

Synthesis of 36 S- labeled perphThe radiosynthesis was

some modifications necessacontaining radioactive sulfproduced radioactive 2-ch

Trilafon is the registered t Present address: Departm

Pittsburgh 13, Pa.I Present address: Montefio

416 JACK R. COOPER and MoHArm,1s M. Knot Biochemical Pharmacology , 1962, Vo

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