Casual attributions for success and failure for psychiatric rehabilitees and college students.

College students and psychiatric rehabilitees performed a manual dexterity task in which consistent success or failure was maipulated over four consecutive task trials. Contrasting predictions for the use of casual attributions (luck, task difficulty, effort, and ability) following Trial 1 and Trial 4 for the two populations were derived from Heider's balance theory and "naive theory of action". Consistent with native theory, students who succeeded and rehabilitees who succeeded used unstable attributions only college students who failed used stable attributions to account for these trial outcomes, whereas students who failed and rehabilitees who failed made significant changes in their attributional patterns from Trial 1 to Trial 4. Results are discussed regarding intervention with psychiatric rehabilitees and other groups with severe achievement difficulties.


Effects of colestipol hydrochloride on drug absorption in the rat II.

The effects of colestipol hydrochloride, a hypocholesterolemic bile acid-binding anion-exchange polymer, on the GI absorption of drugs commonly used in humans were studied in the rat. Colestipol hydrochloride was given by gavage in single doses of 71.5 or 214.5 mg/kg, equivalent to 5 or 15 g, respectively, in a 70-kg human; controls received equivalent amounts of microcrystalline cellulose. Single oral doses of labeled drugs were given concurrently with colestipol hydrochloride or microcrystalline cellulose at the human therapeutic dose range on a milligrams per kilogram basis. Subsequent changes in serum drug levels were measured at several time periods, and absorption was evaluated as the total area under the time-concentration curve. Colestipol hydrochloride at either dose did not significantly alter the absorption of 6-14C-nicotinic acid, 7-3H-tetracycline, 35S-chlorpromazine, 12alpha-3H-digoxin, warfarin (alpha-14C-benzyl), or clofibrate (14C-carboxyl). In addition, the effects of 214.5 mg/kg of colestipol hydrochloride were compared with the same dose of cholestyramine with respect to the absorption of 3-14C-hydrochlorothiazide, 2-14C-phenobarbital, and 3H-digitoxin. Cholestyramine reduced absorption of hydrochlorothiazide by 42%, but colestipol hydrochloride had no significant effect. Neither resin altered phenobarbital or digitoxin absorption when compared with the the control, but a significant difference occurred between the two resins with digitoxin; areas under the time-concentration curve [in (dpm/0.1 ml serum) x hr] were: colestipol hydrochloride, 2001; cholestyramine, 16,300; and cellulose, 17, 067. These results indicate that colestipol hydrochloride and cholestyramine can differ in their effects on the absorption of certain drugs from the GI tract of the rat.


Effects of film coatings on tablet hardness.

The effects of five conventional film-coating materials on tablet hardness were studied. Placebos showed apparently linear increases in hardness as coatings were applied. Completely coated samples exhibited hardness increases from 50 to 140%, with a corresponding 3% increase in tablet weight. Equations were derived relating hardness changes to the "breaking strength" of the film on the tablet. Findings indicate that the coatings exert their influence primarily along the diameter of the tablet in a direction perpendicular to an applied compressional force. Furthermore, the coating process itself did not alter core hardness since tablets from which the film could be stripped showed original values.


Quantitative precorneal disposition of topically applied pilocarpine nitrate in rabbit eyes.

The present study was designed to quantitate the influence of several precorneal factors on the disposition of topically applied ophthalmic drugs. With tritiated pilocarpine nitrate methodology was developed for in vivo assessment of the relative contribution of tear turnover, instilled solution drainage, and nonproductive absorption to the loss of drug from the precorneal area. Studies were conducted in both awake and anesthetized rabbits whose drainage ducts were either unobstructed or plugged, and the loss of drug was monitored directly from the precorneal area or as appearance in the aqueous humor. By selective variation in experimental conditions, the influence of tear turnover, instilled solution drainage, and nonproductive absorption on ocular drug bioavailability was separately studied and quantitated. Instilled solution drainage was by far the largest contributing factor in the loss of drug from the precorneal area of the eye and, in the range of instilled volumes normally employed, tear turnover played a relatively minor role in drug loss. Compared to the cornea, precorneal tissue other than the cornea has a considerably greater surface area and thus is a potentially signifanct route for drug loss. However, under normal circumstances, loss by this route was minimal as compared to loss via instilled solution drainage.


Substitued 5-nitro-1, 3-dioxanes: correlation of chemical structure and antimicrobial activity.

Various derivatives of 5-nitro-1, 3-dioxane were synthesized to determine the relative effect of chemical substitution in the 2-and 5-positions on broad spectrum antimicrobial activity. Each compound was evaluated quantitatively by calculation of a microbiocidal index, which measured the time to kill several different microorganisms. This test system indicated that 5-bromo-5-nitro substitution was essential for significant activity. Optimal activity was effected by 2-methyl substitution in the alkyl series and 2-hydroxy-phenyl substitution in the aryl series. The antimicrobial activity of the substituted dioxanes was not related directly to water solubility or hydrolysis to microbiocidal diols or aldehydes.


GLC and NMR analysis of isomeric impurities in the new anti-inflammatory agent benoxaprofen.

GLC and NMR methods are described for the determination of four possible isomeric impurities in the novel anti-inflammatory agent benoxaprofen. The 2- and 3-chlorophenyl isomers were determined by GLC after alkaline hydrolysis and subsequent methylation. A rapid NMR procedure, using the lanthanide shift reagent tris- (1, 1, 1, 2, 2, 3, 3-heptafluoro- 7, 7-dimethyl- 4, 6-octanedionato)-europium, was developed for the 6- and 7- (alpha-methylacetic acid) isomers. Similar methodolology, with tris-(3-heptafluorobutyryl-d-camphorato)europium, enabled the determination of the enantiomer ratio for benoxaprofen. For the positional isomers, the limits of detection were 0.05% by GLC and 0.2% by NMR.


Fluphenazine enanthate and fluphenazine decanoate: intramuscular injection and esterification as requirements for slow - release characteristics in dogs.

14C-Fluphenazine base was administered intramuscularly in sesame oil to five male beagles (2 mg/kg). The concentration of radioactivity in plasma and the excretion of radioactivity in urine and feces were measured for 14 days. Maximum concentrations of radioactivity were found in plasma 2 hr after administration. These levels declined with elimination half-lives of 3.20 hr during the 2-12-hr interval after dosing and of 4.02 days during the 2-14-day interval. Most administered radioactivity was excreted during the first 2 days after dosing, predominantly in the feces. An average of 0.43% of the dose was present at the injection site 14 days after dosing; some residual radioactivity was found in the liver and in the ocular portion consisting of the combined retina, choroid, and sclera. 14C-Fluphenazine and its enanthate and decanoate esters were each administered intravenously to three different groups of intact dogs at doses of 1 mg/kg. Regardless of which compound was administered, concentrations of radioactivity in the plasma of these dogs were comparable. Thirty minutes after these dogs had been dosed with 14C-fluphenazine enanthate or 14C-fluphenazine decanoate, most radioactivity in the plasma was present as 14C-fluphenazine base and other unidentified metabolites; at this time, at least 79% of either of the two 14C-fluphenazine esters had been biotransformed. The excretion of radioactivity by these same three groups of dogs was very similar, regardless of which of the compounds was given. In 7 days, an average of only 3-4% of the dose was excreted in urine; the remainder was excreted in feces. 14C Fluphenazine and its enanthate and decanoate esters (1 mg/kg) were administered intravenously to dogs whose bile ducts had been cannulated. The amounts of radioactivity excreted in the urine and bile in 8 hr were very similar, as were the residual amounts of radioactivity present in selected tissues. Comparison of the data obtained from dogs given these three compounds intravenously (unformulated) or intramuscularly in sesame oil points to the following conclusions: (a) fluphenazine base per se does not provide slow-release characteristics unless it has been esterified, for example, with heptanoic or decanoic acid, and (b) intramuscular rather than intravenous administration of these two esters is responsible for producing their slow-release characteristics.


GLC determination of aprindine: quantitation and stability measurement.

A GLC method of analysis of a new antiarrhythmic agent, aprindine, is described. The raw material of the new drug substance, supplied as the hydrochloride salt, is dissolved in deionized water, and the base is liberated by a 10% aqueous solution of sodium carbonate. aprindine is extracted with chloroform and mixed with the internal standard, 5alpha-cholestane. GLC is perfomed on a glass column packed with 3.8% W-98 on Chromosorb W-HP. Quantitation is achieved by computer calculation of the peak area ratios. GLC-mass spectral analysis indicates that the observed peak is that of aprindine, with a molecular ion at m/e 322. The retention times of aprindine and the internal standard are 2.0 and 5.8 min, respectively. All synthetic precursors show a shorter retention time than aprindine. This GLC method is applied to the quantitative determination of aprindine as raw material and in capsule and ampul formulations. The method is also used to measure the stability of aprindine to acid, base, dry, heat, refluxing, and UV light and to pH variations.


Comparative plasma concentrations of quinidine following administration of one intramuscular and three oral formulations to 13 human subjects.

A GLC method, based on flame-ionization detection, was developed for the assay of methotrimeprazine and its sulfoxide in plasma. For a 6-ml aliquot, the sensitivity was 2-3 ng/ml for the unchanged drug and 4-5 ng/ml for the sulfoxide. The coefficient of variation, calculated from duplicate analyses of plasma samples, was 8-15% for concentrations between 10 and 100 ng/ml. Patients treated with orally administered methotrimeprazine had higher plasma levels of the sulfoxide than of unmetabolized drug. The method also was applied to the analysis of promazine and chlorpromazine in patient plasma.


GLC determination of methotrimeprazine and its sulfoxide in plasma.


Drug release from methyl acrylate-methyl methacrylate copolymer matrix III: stimultaneous release of noninteracting drug-excipient mixtures.

The simultaneous release of mixtures of noninteracting chemicals incorporated in a methyl acrylate-methyl methacrylate copolymer was studied. Different mixtures of dextrose-methapyrilene hydrochloride and sodium chloride-methapyrilene hydrochlodire in the plastic were compressed into tablets, and single-surface release was obtained in 0.N HCI at 37 degrees. The amounts of both drug and excipients released per unit surface rate constants were analysed in terms of the solubility, diffusion coefficient, concentrations of each chemical, and porosity and tortuosity of the tablets. It was concluded that for each tablet system the individual solid-liquid boundaries of the incorporated chemicals had merged together, and the release could be explained by Higuchi's square foot of time relationship.


Binding of spirolactones to human plasma proteins.

The lipophilicity and plasma binding of 16 spirolactones and 4 hydroxy acid analogs were determined. Mathematical expressions were derived to correlate quantitatively the extent of plasma binding to the lipophilicity of the drugs. The nonspecific binding of these spirolactones and their hydroxy acid analogs was also analyzed using purified serum albumin. A computer program was developed to examine the mechanism of drug-serum protein interactions. One class of binding sites was observed for the range of concentrations used. The number of binding sites and the equilibrium binding constant were computed and were sensitive to substitution at the C-6 and C7 positions. Hydrolysis of the C-17 lactone ring in spirolactones to form hydroxy acid analogs resulted in a decrease in the lipophilicity and, hence, the equilibrium constant for binding.


Rationale for apparent differences in pharmacokinetic aspects of model compounds determined from blood level data and urinary excretion data in rats.

Results of studies carried out in rats for model compounds, D-(-) mandelic acid, benzoylformic acid, and some of their para-alkylated homologs, showed that their biological half-lives determined from the elimination phase of urinary excretion data were longer than those determined from the elimination phase of blood level data. With compounds that followed multicompartment open models, the initial distributive phase (alpha-phase) noted from the blood level data was not detected from the urinary excretion data. Based on the analysis of half-life data obtained in the absence and presence of DL-tropic acid (a competitive renal tubular secretion inhibitor of these compounds), it is proposed that, besides the shortness of the alpha-phase period, the factor accounting for these compounds is their retention and/or detention in the renal tubular membranes during their tubular secretion. Furthermore, it is proposed that the renal tubular membranes do not constitute a part of the central or peripheral compartment. Examples are cited to show that, where studies are reported for the same drugs in the same human subjects in the same laboratory, drugs usually exhibit longer biological half-lives when urinary excretion data rather than blood level data are used.


Influence of cholestasis on drug elimination: pharmacokinetics.

A two-compartment model representing the body and the GI tract, with elimination occurring in each compartment, was used to study, in theory, the influence of impaired biliary excretion on drug disposition. The results suggest that cholestasis can either increase or decrease a drug's half-life, depending upon the relative values of the two elimination rate constants, In all cases, however, impaired biliary excretion reduced the initial elimination of drug from the body and increased the half-life of the alpha-phase of drug disposition.


Biliary secretion of methotrexate in rats and its inhibition by probenecid.

The biliary secretion of methotrexate was investigated in rats under steady-state conditions. The transport system involved was saturable and displayed Michaelis-Menten-type kinetics. Values for the maximal rate of transport and a transport constant analogous to the Michaelis constant were 12 mg/hr and 32 mg/liter (7 x 10-5 M), respectively. The inhibition of this transport mechanism by probenecid also was investigated, and the relationship between the plasma concentration of probenecid and the biliary clearance of methotrexate was elucidated. The value of Ki, the dissociation constant for the transport carrier-inhibitor complex, was 23 mug/ml (8 x10-5 M).


GLC determination of nylidrin in human urine samples.

A method for the detection of nanogram quantities of nylidrin in human urine is described. The method involves beta-glucuronidase hydrolysis, extraction with chloroform, derivatization by silylation, and GLC determination. The suitability of the method was tested by analysis of urine samples of subjects after oral ingestion of nylidrin hydrochloride.


Assay of sulfonylureas in human plasma by high-performance liquid chromatography.

A sensitive and specific high-performance liquid chromatographic procedure for the determination of chlorpropamide or tolbutamide in plasma in the presence of their metabolites is described. The ether extract of acidified plasma is redissolved in the mobile phase, 17% acetonitrile in 0.05 M aqueous ammonium formate, and chromatographed on a reverse-phase column on a high-performance liquid chromatograph fitted with a UV absorbance detector. Quantitation of plasma samples containing less than 0.5 mug/ml of chlorpropamide and 5 mug/ml of tolbutamide is reported, using these drugs as mutual internal standards. The retention times of the metabolites are such that they do not interfere in the procedure. The assay method was tested in a human volunteer with both drugs and found suitable for single-dose pharmacokinetic studies.


Effects of intravenous dantrolene sodium on respiratory and cardiovascular functions.

Dantrolene sodium, a peripherally acting skeletal muscle relaxant, at doses up to 30 mg/kg iv had no effect on respiratory volume, respiratory rate, blood pressure, or heart rate in anesthetized dogs. The ED50 for inhibition of skeletal muscle contractions was 4.5 mg/kg in anesthetized dogs. In anesthetized sheep, the ED50 for skeletal muscle relaxation was 3.2 mg/kg under methoxyflurane anesthesia and 1.7 mg/kg under pentobarbital anesthesia. Unanesthetized sheep administered doses up to 30 mg/kg iv evidenced no dose-related cardiovascular effects. Respiratory volume decreased and respiratory rate increased, with the net result that the respiratory minute volume was not affected by dantrolene sodium. The results indicate that dantrolene sodium has no effect on the cardiovascular or respiratory systems that would preclude its use intravenously in acute conditions where direct relaxation of skeletal muscle is required, as in the management of malignant hyperthermia.


Spectrophotometric study of complex formation between oxovanadium (IV) and antiamebic drugs.

Complex formation between oxovanadium(IV) and the antiamebic drugs 5, 7-dibromo-8-quinolinol and 5, 7-dichloro-8-quinolinol was studied in the pH 1.5-2.0 range, using ethanol, dioxane-water, and dimethylformamide as solvents. The composition of the formed complexes was determined by more than one procedure. In ethanol and dioxane-water, the 1:1 and 1:2 complexes were formed; in dimethylformamide, the 1:1, 1:2 and 1:3 complexes were formed. The stability constants were computed using two procedures: the molar ratio method and the extrapolation method. The reproducibility or results in satisfactory.


Hypocholesterolemic agents V: Inhibition of beta-hydroxy-beta-methylglutaryl coenzyme A reductase by substituted 4-biphenylylalkyl carboxylic acids and methyl esters.

Eleven substituted 4-biphenylylalkyl carboxylic acids and three methyl esters were synthesized and assayed for inhibition of rat liver beta-hydroxy-beta-methylglutaryl coenzyme A reductase. Five of the acids were analogs, resulting from various isosteric replacements of the carbonyl and ether oxygens of the previously described reversible inhibitor 1-(4-biphenylyl)pentyl hydrogen succinate. No significant change in activity was noted, except upon introduction of an amide linkage where a decrease in inhibition was found. Six carboxylic acids and three methyl esters, all containing the 4-biphenylyl radical but lacking the n-butyl side chain found in 1-(4-biphenylyl)pentyl hydrogen succinate, also were inhibitors of the reductase.


Physical characterization and activity in vivo of polymorphic forms of 7-chloro-5, 11-dihydrodibenz[b, e][1, 4]oxazepine-5-carboxamide, a potential tricyclic antidepressant.

The biological availability in dogs and humans of 7-chloro-5, 11-dihydrodibenz[b,e][1,4]oxazepine-5-carboxamide, a potential antidepressant drug, was increased when the compound was administered in capsule formulations as micronized drug coated with 1% sodium lauryl sulfate or as a lyophilate with poloxamer 407. This increase with these two formulations had been predicted by dissolution tests in vitro. The lyophilized combination with poloxamer 407 was more soluble in 0.1 N HCl than was the untreated compound. Characterization of the lyophilate by differential thermal analysis, X-ray diffraction, and IR spectroscopy indicated that the increase in solubility was attributable to the formation of a polymorphic from. a polymorph of the compound designated form 8, was prepared. The solubility and dissolution characteristics of the two polymorphic forms, A and B, as well as of the lyophilized combination with poloxamer 407, were determined.


Epimeric 5-hydroxy-5-phenyl-1-azabicyclo [5.4.0] undecanes.

The development of order during the aging of aluminum hydroxide gel prepared by the reaction of aluminum chloride and ammonium hydroxide to a final pH of 7.0 can be monitored by differential thermal analysis. The loss fo acid reactivity upon aging is accompanied by an increase in the temperature and intensity of the dehydroxylation endotherm and an accompanying decrease in the intensity of the water of hydration endotherm. With continued aging, the thermogram develops the characteristics of a crystalline aluminum hydroxide.


Differential thermal analysis of aluminum hydroxide gel.

The development of order during the aging of aluminum hydroxide gel prepared by the reaction of aluminum chloride and ammonium hydroxide to a final pH of 7.0 can be monitored by differential thermal analysis. The loss of acid reactivity upon aging is accompanied by an increase in the temperature and intensity of the dehydroxylation endotherm and an accompanying decrease in the intensity of the water of hydration endotherm. With continued aging, the thermogram develops the characteristics of a crystalline aluminum hydroxide.


Extraction and GLC analysis of pyrithyldione in highly putrified human postmortem samples.

Pyrithyldione was isolated from highly putrified human brain and small intestine samples by ether extraction followed by alumina column cleanup. The total yield was 90+/- 5%. No derivatization was necessary prior to GLC analysis.


Pharmacokinetics of skin penetration.

A model for estimating in vivo skin permeability coefficients is presented. Explicit expressions are derived for the permeability coefficient in terms of excretion rates and tissue absorption. The excretion rate has a linear asymptotic limit from which the permeability coefficient can be determined. The usefulness of the model is demonstrated with existing literature data.


Tumor inhibitory agents from Vauquelinia corymbosa (Rosaceae).

The chloroform extract of Vauquelinia corymbosa Correa has shown activity against the P-388 lymphocytic leukemia test system. The constituents responsible for this activity were identified as uvaol, ursolic acid, and betulinic acid. Their identity was proven by melting point; mixed melting point; elemental analysis; IR, PMR, and mass spectra; and preparation of derivatives.


Stimulation of the rabbit hypothalamus: caudal projections to respiratory and cardiovascular centres.

1. Electrical stimulation of a small area of the hypothalamus, lying about 2 mm dorsal to the lateral margin of the mammillary bodies, evoked a characteristic complex of effects in the anaesthetized rabbit. 2. The observed effects included apneusis followed by tachypnoea, increased arterial blood pressure, and vagally mediated bradycardia. Exophthalmost and pupillodilatation was commonly seen. The ears were erected and the vibrissae drawn forward. Somatic effects were weaker, but often included increased extensor tone, especially in the forelimbs. 3. The intensity of these effects was dependent upon the frequency of stimuli within the trains. Effects were weak or absent below 20 shocks/sec, and were near-maximal above 60 shocks/sec, when employing constant-current rectangular wave stimuli of 100-300 muA, 1 msec pulse duration and 5-9 sec train duration. 4. The effects were not dependent upon connexions with the cerebral cortex, but were mediated by pathways that projected ipsilaterally from each side of the hypothalamus through the mesencephalon. 5. The evidence suggests that this region of the rabbit hypothalamus is partly homologous with that hypothalamic area associated with the defence reaction in cat. However, the over-all responses to stimulation in the anaesthetized rabbit differed considerably from those described in the anaesthetized carnivore, suggesting that their integrated physiological responses to emotional threat are dissimilar.


Calcium exchange in vascular smooth muscle, action of noradrenaline and lanthanum.

1. The Na, K, Ca and Mg content and the 45Ca uptake and loss were determined in rat aortae incubated in physiological solution or in solution containing LaCl3 instead of CaCl2. 2. Aortae washed in La-solution contained less Ca and Na than controls in physiological solution, the K content was not modified and the Mg content was slightly decreased. 3. In 50 mM-La solution the 45Ca diffusion space was intermediate between the values found for the [14C]sorbitol space and the [14C]inulin space, indicating that there was no Ca entry within the cell nor Ca binding at superficial sites. 45Ca loss from the tissue was directly related to the La concentration. 4. Noradrenaline increased the rate of uptake of 45Ca into the Ca fraction resistant to displacement by La. This increase was dose dependent, a response of 50% of the maximum being produced by 2 x 10(-8) noradrenaline as for the contraction. In the presence of phentolamine, the dose-effect curves for the action of noradrenaline on 45Ca uptake were displaced in a manner characteristic of competitive antagonism. The rhoA2 for phentolamine was 7-8. 5. In physiological solution, the rate of loss of 45Ca, from the Ca fraction resistant to displacement by La, was increased by noradrenaline the ED50 was 2 x 10(-8) M, and the effect was abolished by phentolamine. 6. In view of the similarity of phentolamine rhoA2 estimated by measuring noradrenaline sensitive 45Ca uptake or noradrenaline evoked contraction, it is likely that the activation of alpha-adrenergic receptors is responsible for both effects.


Influence of amygdala stimulation on the activity of identified tuberoinfundibular neurones in the rat hypothalamus.

1. Extracellular action potentials were recorded from 1246 neurones in the mediobasal hypothalamus of pentobarbitone or urethane anaesthetized male rats. Antidromic invasion from the surface of the median eminence identified 165 cells, located in the arcuate and ventromedial nuclei and the periventricular area, as tuberoinfundibular neurones. The majority (65%) of these cells displayed no spontaneous activity. 2. Latencies for antidromic invasion from median eminence ranged from 0-5 to 14-0 msec (mean 4-3 +/- 2-9 msec, S.D.). Conduction velocities for axons of tuberoinfundibular neurones were under 1-0 m/sec, and were slowest (under 0-2 m/sec) for those tuberoinfundibular neurones located in the arcuate nucleus. 3. Single 1 HZ stimulation of amygdala evoked short latency (mean 18-8 +/- 7-0 msec; n = 30) excitation of tuberoinfundibular neurones in the ventromedial nucleus. Stria terminalis stimulation evoked similar responses at a shorter latency (mean 10-2 +/- 3-5 msec; n = 12) from other ventromedial tuberoinfundibular neurones. Three of these neurones were also excited by amygdala stimulation at comparably longer latencies. In spontaneously active tuberoinfundibular cells, the initial excitation was followed by a decrease in excitability lasting 70-150 msec. Tuberoinfundibular neurones soldom followed orthodromic activation at frequencies beyond 30 HZ. 4. An initial decrease in activity at latencies of 18-40 msec (mean 29-2 +/- 10-2 msec) characterized the amygdala evoked responses from nine tuberoinfundibular neurones. A similar response from one other tuberoinfundibular neurone followed stria terminalis stimulation at a latency of 11 msec. Most of these tuberoinfundibular neurones were located in the dorsal part of the ventromedial nucleus. 5. Two ventromedial tuberoinfundibular neurones also displayed antidromic invasion from the amygdala; interaction studies suggested an axon collateral pathway that originated close to the origin of the axon. 6. Tuberoinfundibular neurones unresponsive to amygdala stimulation were usually located in the arcuate nucleus or periventricular area. 7. These results provide electrophysiological evidence for a direct influence of the amygdala on the activity of tuberoinfundibular neurones in the ventromedial hypothalamic nucleus. There are also data to indicate that some ventromedial tuberoinfundibular neurones have axon collaterals that return to the amygdala. These reciprocal connexions between the amygdala and ventromedial tuberoinfundibular neurones may indicate neural circuits important for extrahypothalamic modulation of adenohypophyseal secretion.


The effect of temperature on the reaction of carbon monoxide with oxygenated haemoglobin.

1. The rate at which carbon monoxide displaces oxygen from its combination with haemoglobin in solution, has been measured spectrophotometrically, using a rapid-mixing stopped-flow technique. 2. In the presence of carbon dioxide, the reaction proceeds by a unimolecular dissociation, with a rate constant r. 3. The relationship of the reciprocal of r to the ratio PO2/PCO is non-linear, and a different curve is obtained at each carbon monoxide concentration. 4. From measurements of the rate constant at temperatures between 5 and 35 degrees C, it is concluded that the non-linearity is due to the formation at a finite rate of an intermediate complex, CO2Hb4O6, by the reaction of carbon dioxide with Hb4O6.


Energetics of isovolumic contractions of the isolated rabbit heart.

1. In the isolated beating rabbit heart the heat production (measured by Dewar-flask calorimetry) and oxygen consumption (measured polarographically) increased in a similar way to force development (assessed as the time integral of left ventricular developed pressure) when the diastolic size of the heart was increased. 2. The energy expenditure of the heart consists of an element which is independent of the force developed and another which varies with the force developed. 3. The calorific equivalent of oxygen in the beating heart when it was provided with pyruvate as a substrate was found to be 20-48 mJ/mul: O2 at 25 degrees C. 4. The anaerobic metabolism was well below 5% of the total energy liberation and was constant at all levels of mechanical activity.


The effects of potassium and temperature on the pace-maker current, iK2, in Purkinje fibres.

1. The reversal potential for the pace-maker K current, iK2, was measured in sheep cardiac Purkinje fibres at extracellular K concentrations, [K]O, between 2-7 and 8 mM. The reversal potentials were found to be significantly more negative than the values predicted using the Nernst equation for any reasonable value of intracellular K+ concentration or activity. 2. It is suggested that this discrepancy may be explained by postulating that the extracellular K+ concentration [K]e in the cleft spaces between cells is smaller than [K]o as a result of ion pumping and restricted diffusion from the bulk extracellular medium. 3. In conformity with this hypothesis, it was shown that the value of [K]e may be further reduced by hyperpolarizing pulses, presumably as a consequence of K+ depletion during the passage of inward current. 4. The influence of temperature on the kinetics of the gating mechanism, s, controlling iK2 was investigated. The Q10 for the time constant, pis, of current change following voltage clamp steps was found to be about 17. This corresponds to an apparent activation enthalpy of 50 kcal/mole. 5. The Q10 of the maximum amplitude iotaK2, was found to 1-3. 6. The activation curve, s infinity (Em), spread slightly to more negative potentials by cooling from 37 to 30 degrees C and the curve became less steep. 7. There is a large decrease in the inward background current on cooling, as estimated by measuring the net membrane current when iK is presumed to be zero, i.e. at the reversal potential for iK2.


An analysis of the actions of low concentrations of ouabain on membrane currents in Purkinje fibres.

1. The influence of low concentrations (5 X 10(-8) to 5 X 10(-7) M) of ouabain on the K gradient in sheep cardiac Purkinje fibres was observed by measuring changes in the reversal potential for a K specific current iK2, and by measuring total steady-state current-voltage relations. 2. Provided that the bathing solution K concentration, [K]o  was not too low, these doses of ouabain were often observed to increase the K gradient, i.e. the reversal potential was shifted in a negative direction. 3. The change in the reversal potential and in the current-voltage relation could be mimicked by reducing the value of [K]o in the absence of ouabain. It is therefore suggested that ouabain may stimulate the Na+-K+ exchange pump and so reduce the K concentration, [K]e, in the clefts of the preparation. 4. At sufficiently low values of [K]o, a dose of ouabain that was stimulatory may become inhibitory. The reversal potential for iK2 then shifts in a positive direction. 5. During either stimulation or inhibition, the speed of change of reversal potential is consistent with a change in [K]e, which may change fairly rapidly. It is not possible to account for the results solely by changes in intracellular concentration, [K]i. 6. Low concentrations of ouabain were found to have no effect on the activation curve, s infinity (Em), controlling iK2. It is concluded that the changes in iK2 are solely attributable to changes in reversal potential. 7. Since net stimulation of the Na+-K+ exchange pump was observed to occur at doses of ouabain that exert a strong positive inotropic action on Purkinje fibres (Blood, 1975), it is not likely that the inotropic action is causally related to net pump inhibition.


[Digestion and absorption of dietary triglycerides].

This review is an attempt to put in order some facts obtained during twenty-five years of studying the digestion and absorption of dietary triglycerides. After a short history of this problem to show the progress of research, the active mechanism of pancreatic lipase on triglycerides is explained: this enzyme specifically hydrolyses fatty acids esterified with the primary hydroxyl groups of glycerol, forming 2-monoglycerides and free fatty acids. This fact is very important for the further process involving formation and composition of intraluminal micelles, along with absorption and de novo synthesis of triglycerides inside enterocytes. Several different points are disscussed: - Short or medium chain-length fatty acids are hydrolyzed more easily than long-chain ones; after their absorption, the former go to the liver by the portal circulation and the latter go to lymph. - An evaluation of the extent of digestive hydrolysis has been given by means of doubly-labelled triglycerides (glycerol and fatty acids), and by comparing isotope ratio values of lymph and dietary triglycerides. - The physico-chemical state that intraluminal fats are in is discussed; 2-monoglycerides and fatty acids released from triglyceride hydrolysis form macromolecular agregates with biliary salts and phospholipids, cholesterol, and dietary phospholipids (or their degradation products). These are termed mixed micelles and are absorbed by diffusion. - Many recent morphological studies carried out with the electron microscope are indicated. - Two metabolic pathways for triglyceride resynthesis in the mucosal cells have been established, one from free fatty acids and alpha-glycerophosphate, the other from 1 or 2-monoglycerides. Phosphatidic acids are involved in this resynthesis, but the role of other phospholipids is almost certainly not so narrowly limited. - The apparent digestibility of fats according to their fatty acid composition, and mainly according to the location of the fatty acids in the initial triglyceride molecule, is discussed. - The nature and importance of endogenous fatty acids in the digestive tract and lymph is discussed. - The lipid and fatty acid composition of lymph chylomicrons is given. - The importance of lymph lipid particles (average diameter 0,05 less than or equal mum) for transport of exogenous fatty acids is indicated. The biochemical mechanism involved in the digestion and absorption of dietary lipids are now well known, but some processes are still uncertain, particularly the physico-chemical state of intraluminal lipids, the role of enterocyte membranes, the synthesis and secretion of digestive enzymes, and the role of intestinal flora.


[Hand blood flow at rest and during submaximal exercise in acute and chronic heat stress (author's transl)].

Three groups of subjects, Europeans without any heat acclimation (called EE), Europeans after 3 weeks of acclimatization in India (EI), and Indians in their natural environment (II) were studied during exposure to an ambient temperature of 33 degrees C. Hand blood flow (Q), rectal temperature (Tre), mean cutaneous temperature (Tsk) were simultaneously recorded at rest and during 2 periods of muscular exercise (0.44 and 0.7 Vo2 max) of 35 mn duration. The results showed (1) at rest, Q was very high in EE, quite low in both EI and II; (2) at the onset of exercise, a hand vasoconstriction was observed in all cases; (3) during exercise, there was a progressive increase of Q until 200% maximum above rest values; (4) at the end of exercise, Q was proportional to the intensity of the exercise for each group and inversely proportional to the duration of heat exposure, the highest Q was observed in EE, the lowest in II and an intermediate value for EI close to the latter). These differences in hand blood flow could not be explained by differences in deep and/or superficial temperatures between subjects. Thus, during chronic heat exposure, there is, especially for an exercising man, a progressive modification of heat transport in the body: that is, a reduction of skin perfusion and a greater Tre-Tsk difference which are both adaptative responses. The value of hand blood flow as an estimation of whole superficial circulation is discussed.


Vocational training for general practice-the Spalding seminars. A technique of topic teaching for trainees.

A technique for topic teaching for vocational trainees is described which matches trainees to patients to illustrate different facets of the topic under discussion.


Music and handicapped children.

Handicapped children may gain considerably from being introduced systematically to musical sounds. The benefit comes not only from enjoyment, but also from promoting intellectual, emotional, and social development. Some children who are severely handicapped intellectually may have great musical talent, such as perfect pitch, and if this is systematically cultivated a key can sometimes be found unlocking the barriers to the child's progress. Some examples are described.Several years' experience of working as a music therapist with children both normal and handicapped have convinced me that the use of music as an aid to learning is worth further study and research.


Complications of "slow-K" therapy.

(1) The failure of ;Slow-K' tablets to disintegrate prevents rapid release but allows them to be trapped by their bulk in the intestine.(2) Two cases are reported. In the first the tablet was trapped in a caecal diverticulum and the patient developed an abcess. In the second, abdominal pain developed which subsided when ;Slow-K' was stopped. Later ;Slow-K' was again started and the patient developed dysphagia.(3) The possibility of abdominal complications with this treatment should be remembered.(4) Effervescent KC1 preparations may replace ;Slow-K' but KC1 supplementation may be necessary only in cardiac disease.


Consultation patterns in a general practice.

A study from the Oxford Community Health Project is reported on the effects on consultation rates in general practice of patients' age, sex, date of registration, address, and usual doctor. The impact on consultation rates of accessibility of surgeries and availability of doctors is examined when the variables are controlled, and the importance of these factors is discussed in relation to planning primary medical care.


Otitis externa in children.

The commonest cause of ear-ache in children is otitis externa and five new cases of otitis externa will be seen for every case of otitis media.ACUTE OTITIS EXTERNA AND OTITIS MEDIA ARE QUITE DIFFERENT AND DISTINCT CLINICAL ENTITIES IN CHILDREN: the former is a tender, dirty, pruritic ear, often recurring in children with simple febrile illnesses; the latter is more isolated than is realised, non-recurrent and usually accompanying upper respiratory catarrhal illness.The fleeting nature of otitis externa as seen in childhood is typical of clinical material in general practice that presents quite differently from that in hospital practice. The long aetiological lists quoted in all series of cases of otitis externa in adults do not apply to otitis externa as seen in children.


Illness in a summer holiday camp.

(1) The medical needs of patients staying at a holiday camp during the summer of 1974 have been analysed.(2) Medical advice was sought from a doctor about half as often as would have been expected from a comparable population at home, but the camp nurse saw three times as many patients as the doctor.(3) The clinical content of the consultation was analysed.(4) The outcome of the consultations and the role played by the nurse are discussed.


Lead and multiple sclerosis.

It has been suggested that lead may be a cause of multiple sclerosis, but confirmation of this hypothesis is difficult to obtain as lead is so widely present both in the environment and in many human tissues.In this study 22 patients with multiple sclerosis were compared with 22 controls. Lead levels in the blood of the patients were not higher and urinary lead levels in the patients before and after a single dose of penicillamine did not provide evidence to support the hypothesis that lead may cause the disease.


A difference in dry mass between the heads of X- and Y-bearing human spermatozoa.

An integrating microinterferometer was used to measure the dry mass of sperm heads. The dry mass was found to be proportional to DNA content, and thus provides a useful method of estimating sperm DNA content. Using this technique we have confirmed that human spermatozoa which show none and one quinacrine-fluorescent spot are X- and Y-bearing respectively. However, the measurements suggest that many of the spermatozoa with two quinacrine-fluorescent spots are not YY-bearing, as previously thought, but might be incompletely condensed Y-bearing spermatozoa.


Protein composition in the fluid of individual bovine follicles.

The proteins in follicular fluid from individual and pooled bovine follicles were studied by gel chromatography and quantitative immunoelectrophoresis. The mean protein concentration was 86-4% of serum; very large proteins were present in only low concentrations. A minimum of 40 individual proteins was distinguished in follicular fluid, and 15 of these proteins were quantitated. A correlation between molecular weight and follicular fluid: serum concentration ratio was found. Fluid from individual follicles differed only in the relative concentrations of small and large proteins. An exception to this was IgG which was occasionally, but never in healthy growing follicles, present in concetrations above 150% of serum. Healthy growing, preovulatory and atretic follicles had higher, and cystic follicles mostly lower, concentrations of small proteins than serum. The concentration of alpha2-macroglobulin in healthy growing follicles never exceeded 16% of serum. The concentration of large proteins in follicular fluid increased with increasing follicle size. Attempts to detect proteins specific to follicular fluid by immunizing rabbits with pooled follicular samples and the follicular fluid proteins not bound by anti-bovine antiserum resulted in production of antibodies against fibrinogen and its split products D+E only.


Effect of removal of epididymal secretions on fertilization in vitro of mouse eggs.

The removal by centrifugation of epididymal contents from mouse spermatozoa had no deleterious effect on fertilization in vitro, and, depending on the genotype of the gametes, was frequently associated with increased levels of fertility. Washing of the spermatozoa significantly improved the fertilization rate of F1 eggs with TO spermatozoa and of BALB/c eggs with BALB/c spermatozoa, but had no significant effect of F1 spermatozoa with F1 eggs.


Ultrastructural studies of frozen-thawed 8-cell mouse embryos.

Survival of frozen 8-cell mouse embryos transferred directly upon thawing to the uteri of Day 3 pseudopregnant foster mothers was significantly lower (26%) than the survival of unfrozen 8-cell embryos transferred immediately after collection (73%). When frozen-thawed 8-cell embryos were cultured for 20-24 hr before transfer survival was similar to that of unfrozen 8-cell embryos transferred after 20-24 hr inculture (65% and 73%, respectively). Ultrastructural examination of the frozen-thawed 8-cell embryos revealed no obvious damage to protoplasmic components.


Uterine luminal proteins at the time of implantation in rats.

Changes in rat urerine luminal proteins were analysed during pregnancy and after ovariectomy on Day 3 of pregnancy plus daily administration of progesterone, when delay of implantation is imposed. Total protein levels reached a peak level on Day 5 of pregnancy, the day of implantation, in the intact but not the ovariectomized females. Qualitative analyses of protein-SDS complexes showed an increase in a protein of molecular weight of approximately 70.000 and others of higher molecular weight during pregnancy, but in ovariectomized females the proteins of higher molecular weight were virtually undetectable by Day 10. The entry of blastocysts into quiescence after ovariectomy appears to be an adaptation by the embryos to suboptimal uterine luminal conditions.


The fertilizing capacity of epididymal spermatozoa in relation to age, body weight and the onset of sexual maturity in the golden hamster.

Experiments with prepubertal hamsters were undertaken to determine if the appearance of spermatozoa with fertilizing capacity in the cauda epididymidis is related to age and/or body weight and whether the development of sperm function coincides with complete maturation of the mating behaviour pattern. At Week 6 after birth, intrauterine insemination of comparable numbers of spermatozoa showed that fertilizing capacity was related to body weight and not to age or seminal vesicular fructose concentration. In contrast to the low fertilization rate produced by spermatozoa from males weighing 80 g at Week 6 after birth, spermatozoa from 80-g males at Week 7 showed normal fertilizing capacity. Only 50% of 7-week-old males weighing 100-110 g produced fertile matings whereas all matings were fertile with males weighing 135 g and with males weighing 100 to 110 g that had received 7 consecutive daily injections of 50 mug testosterone beginning at Week 6 after birth. Comparison of sperm numbers in the cauda epididymidis and ductus deferens after mating at Week 7 showed that males which produced sterile matings were unable to terminate intromission with normal ejaculation of spermatozoa.


Proteins in human uterine fluid.

The proteins in saline washings from uteri of women at different stages of the menstrual cycle were examined by polacrylamide gel electrophoresis at pH 4-5 and pH 8-9, isoelectric focusing in polyacrylamide, and immunoelectrophoresis. The components present were mainly serum proteins but small amounts of uterine-specific proteins were also detected. Measurement of the activities of several glycosidases in uterine washings revealed that alpha-L-fucosidase, beta-N-acetylgalactosaminidase and beta-N-acetylglucosaminidase were elevated when compared with serum.


Effects of RMI 12,936, a synthetic antiprogestational steroid, in the rat.

The antifertility effect of RMI 12,936 in the rat is shown to be reversible. Luteal hypertrophy followed administration to pregnant, but not to pregnant hysterectomized rats. Similar hypertrophy followed administration to pseudopregnant, immature gonadotrophin-treated, and immature hysterectomized and gonadotrophin-treated rats, but the ovarian sensitivity to gonadotrophins was reduced or unchanged, suggesting that the ovarian hypertrophy is due to a direct ovarian action of RMI 12,936. Progesterone production on Day 15 of pregnancy by the enlarged ovaries following RMI 12,936 administration on Day 8 was not significantly different from control levels, but there was a highly significantly reduction on Day 9. An isomer of RMI 12,936, Tsomer 201, presumed to be 7alpha-methyltestosterone, was  shown to have antifertility and uterotrophic activities in rats similar to those of RMI 12,936. Unlike RMI 12,936, however, Isomer 201 did show significant cross-reaction in the competitive protein-binding assay for progesterone and did not cause significant reduction in peripheral progesterone levels on Day 9 after administration on Day 8. From this and previous evidence it is concluded that RMI 12,936 inhibits progesterone synthesis, possibly by acting as an alternative substrate for ovarian delta(5)3-ketosteroid isomerase, and that the product is probably a competitive antagonist of progesterone at the receptor level.


Plasma concentrations of testosterone in the developing ram in different social environments.

Plasma testosterone profiles were determined by taking frequent blood samples at intervals from birth to 21 months of age from rams reared in isolation, in an all-male group and in a mixed-sex group. The testosterone pattern was not modified by these different social environments. The ability of the ram to copulate when first exposed to an oestrous ewe, apparently a maturational process, was also independent of social rearing. At birth plasma testosterone levels were detectable but low, they were higher at 10 and 16 weeks of age and showed a marked rise by 26 weeks, coincident with the time of puberty. Depressive effects of season on testosterone profiles occurred during the 2nd year of life but not the 1st year.


Effect of administration of progesterone and oestrogen on litter size in pigs.

Progesterone and oestrone alone or in combination were administered to sows during early gestation. A dose of 25 mg progesterone and 12-5 mug oestrone injected together for 10,5 or 2 consecutive days during the implantation interval caused increased litter size at term.


Uterine proteins and development in vitro of rabbit preimplantation embryos.

The effects of isolated protein fractions from rabbit uteri (prealbumin, albumin, uteroglobin, and beta-glycoprotein), unfractionated uterine proteins, progesterone, oestradiol-17beta, and prostaglandin F-2a on the development of rabbit embryos in vitro were investigated. When exposed to individual protein fractions obtained from Day-6 uteri, 8-cell embryos did not develop into early blastocysts; morulae readily developed into early blastocysts, but further development was retarded. Progesterone (10(-5)-10(-11)M) and prostaglandin F-2a (0-1-10 ng/ml) added to the medium slowed development of blastocysts to advanced stages. Growth of 8- to 16-cell embryos, morulae, and Day-4 blastocysts was stimulated by unfractionated uterine proteins obtained from Day-5 uterine flushings. Although embryos cultured in medium containing BSA had similar rates of blastocyst formation and, ultimately similar blastocyst expansion as did the embryos cultured in medium with unfractionated proteins, the radial and immediate expansion of the early blastocysts cultured in the latter approximated that found in utero.


Embryonic development in rabbits after insemination with spermatozoa stored at 37, 5 or-196 degrees C for various periods.

Rabbit spermatozoa stored at 37 degrees C for 5 hr, 5 degrees C for 5 hr or 5 days, and-196 degrees C for 5 hr, 5 days, or 1 year were used to artificially inseminate does induced to ovulate normal or excess numbers of eggs. Fertility and subsequent embryonic development were examined. Frozen spermatozoa stored for 5 hr fertilized fewer oocytes than those stored for 5 days or longer. Fewer embryos were recovered on Day 6 than on Day 2. Blastocysts were smaller when spermatozoa were stored for 5 days, were frozen or were placed in superovulating does, but no statistically significant differences in the % of fetal survival were found in the groups of normally ovulating does. Embryonic wastage associated with storage of spermatozoa resulted from a reduced fertilization rate and/or increased embryonic mortality before implantation.


Concentrations of fat and plasma 5alpha-androstenone and plasma testosterone in boars selected for rate of body weight gain and thickness of back fat during growth, sexual maturation and after mating.

The levels of 5alpha-androstenone and testosterone in peripheral plasma and 5alpha-androstenone in fat collected from 18 boars selected according to thickness of back fat and rate of gain were evaluated. Sampling was started when the animals were about 100 days of age and samples were collected every 14 days until the boars were about 240 days old. The steroid profiles varied considerably between boars, although an increase in steroid levels was found in most animals with the onset of adolescence. The regression line for the level of 5alpha-androstenone in fat and the age of the animals in days was found to be y = 0.02x-1-31. High coefficients of correlation were found between the concentration of 5alpha-androstenone in peripheral plasma and fat (r = 0-78) and between levels of 5alpha-androstenone and testosterone in peripheral plasma (r = 0-64). Levels of 5alpha-androstenone in peripheral plasma above about 15 ng/ml were usually accompanied by a heavy accumulation of 5alpha-androstenone in adipose tissue. The use of four of the boars for mating resulted in increased steroid levels in peripheral plasma and fat. Significantly higher levels of 5alpha-androstenone and testosterone were found in the peripheral plasma of boars selected for fatness and a low rate of gain than in boars selected for low back-fat thickness and a high rate of gain.


Production, chemical composition and prostaglandin F-2alpha content of uterine fluid in pregnant sheep.

A uterine pouch was prepared surgically in ewes before mating to study the production and chemical composition of uterine secretions during pregnancy. Pregnancy was established in 6 sheep and in the first 55 days uterine fluid was present in small amounts (less than 5 ml), whereas between 109 days post coitum and 3 days post partum the volume ranged from 90 to 775 ml. The chemical composition of uterine fluid in pregnancy differed from that of plasma especially in respect of its high concentration of total calcium (up to 83.5 mM) and prostaglandin (PG) F-2a (up to 1500 ng/ml). Progesterone was implicated as an important endocrine factor since uterine fluid (188 ml) with a high concentration of total calcium (53-5 mM) and PGF-2a(235ng/ml) was recovered from a non-pregnant sheep treated with progesterone for 115 days.


Placental fine structure after experimental embryonic death in cows.

Early embryonic death was experimentally induced by amnion rupture in pregnant heifers. The subsequent morphological alterations in the placenta were studied with light and electron microscopy, histochemical tests and electron microscope microanalysis. The material from the treated heifers differed from that inuntreated cows in the following aspects: the fetal-maternal junction was firm; many endometrial epithelial cells were desquamated and the remaining epithelium showed vacuolization or depletion of organelles; the trophoblast remained at the preattachment stage in its marked phagocytic activity and accumulation of lipid and glycogen, and many of the organelles were degenerated; and the mesenchyme contained extracellular deposits of iron and calcium. It is believed that the changes observed were caused by interruption of the fetal circulation followed by an accumulation of metabolic products.


Macromolecular components of genital tract fluids from the sheep.

The proteins and glycosidases in the luminal fluid from the genital tract of ewes at different stages of the oestrous cycle and early pregnancy were studied. Most of the proteins in oviducal fluid and uterine fluid were serum proteins, but an increased amount of a glycoprotein excluded from Sephadex G-200 was detected in oviducal fluid at oestrus. Small amounts of uterine-specific proteins were detected in uterine fluid by polyacrylamide gel electrophoresis and  isoelectric focusing. The number of these varied according to the stage of pregnancy. The activities of several glycosidases were elevated in uterine fluid when compared with serum; beta-N-acetylgalactosaminidase and beta-N-acetylglucosamindase were particularly active. Ovine cervical mucus was shown to contain an epithelial glycoprotein which had a composition similar to that of the glycoproteins isolated from human and bovine cervical mucus.


Intrauterine contraception with the copper T-200 and the Dalkon shield in nulligravid women.

A randomized, prospective study design compares the small Dalkon shield and the Copper T 200 (T Cu 200) intrauterine contraceptive devices in nulligravid women in the same clinic population during a 12-month period. This prospective study demonstrates statistically significant differences in the accidental pregnancy, expulsion and medical removal rates between the two devices. In nulligravid patients the T Cu 200 had lower event rates than the small shield in the categories of accidental pregnancy and medical removals for bleeding and pain.


Cysteine derivatives with reactive groups as potential antitumor agents.

Cysteine derivatives having diazo ketone and chloro ketone functions have been prepared. In order to effect adequate protection for modifying the carboxyl group, cysteine was converted to a thiazolidine derivative I, which was then converted to the N-acetyl derivative VII. The active ester method or activation with DCC yielded the diazo ketone derivative VIII. Similar treatment of the parent compound I with DCC led to a self-condensation reaction giving a diketopiperazine VI. The diazo ketone derivative VIII has been used in preparing alpha-chloro ketone derivative X and a homologue of cysteine. Deblocking N-acetylated thiazolidine derivatives with various reagents did not proceed satisfactorily. Interaction of the N-acetylated blocked ester XII with trifluoroacetic acid opened the thiazolidine ring to give the N-acetylated blocked diester XIII and other products. The chloro ketone derivative X was found to have a moderate inhibitory activity against mouse mammary adenocarcinoma in cell culture. S-(1-Adamantyl)-L-cysteine was prepared and was found to be inactive.


Synthesis and biological evaluation of omega-homologues of prostaglandin E1.

The synthesis and biological activities of some compounds with novel modifications of the omega side chain of prostaglandin E1 (PGE1) are described. The preparation of (+/-)-omega-Me-PGE1 (3) (+/-)-omega-Pr-PGE1 (5), and (+/-)-omega-Bu-PGE1 (6) is outlined. The compounds were evaluated for in vitro smooth muscle stimulating activity on isolated gerbil colon preparations, for hypotensive action in anesthetized rats, and for gastric antisecretory effects in histamine-stimulated Heidenhain pouch dogs. Structural changes in the omega position of the noncarboxyl side chain of PGE1 influenced the biological potency of the resulting compound when compared to the reference standard PGE1 (2). The homologues demonstrated interesting separation of biological activities; for example, 4 showed potent hypotensive activity (84% of PGE1, it showed very low smooth muscle stimulating activity. Compound 3 possessed the same order of potency as 2 in the gastric antisecretory assay.


Tyrosylated analogues of somatostatin.

The total synthesis of [tyr1]-, [tyr6]-, E1Tyr7], [d-tyr8]-, [tyr11]-,and [tyr1,D-Trp8]somatostatin is described. The biological potencies of these analogues in vitro (inhibition of spontaneous secretion of radioimmunoassayable growth hormone by cultured rat anterior pituitary cells) as compared with that of somatostatin (100) were found to be 116, 29, 108, 10, 65, and 400, respectively; in vivo, in the rat, these peptides were assayed for their ability to inhibit the spontaneous release of insulin and glucagon. No statistically significant discrepancies were observed in the potency values obtained in vitro and in vivo further indicating similarities of specificities and sensitivities of the pituitary and pancreatotropic receptors.


Nucleic acids. 16. Orally active derivatives of ara-cytidine.

Water-soluble derivatives of ara-cytidine (cytarabine, Cytosar) were prepared and tested for antitumor, immunosuppressive, and antiarthritic activities in animals after oral administration. The compounds tested included the 5'-palmitate, 5'-benzoate, and 5'-adamantoate esters of ara-cytidine, made water soluble by use of their hydrochloride salts of peptidyl derivatives, and two basic 5' esters (5'-nicotinoate and 5'-quinuclidinate) as their hydrochloride salts. Five of the compounds had antitumor activity superior to that found with ara-cytidine itself after oral administration in the L1210 leukemic mouse assay. One of these, 5'-adamantoyl-ara-cytidine hydrochloride, had antitumor activity after oral administration approaching that achieved with parenterally administered ara-cytidine.


Synthesis of tetrazole ribonucleosides and their evaluation as antiviral agents. 2. 5-Amino-1-(beta-D-ribofuranosyl)-1H-tetrazole and 5-amino-2-(beta-D-ribofuranosyl)-2H-tetrazole.

Synthesis of 5-amino-1-(beta-D-ribofuranosyl)-1H-tetrazole and 5-amino-2-(beta-D-ribofuranosyl)-2H-tetrazole is described. X-Ray crystallography was first used to establish the stereochemical configuration of the two isomers. By conducting 13C NMR analysis on these isomers with known structures, i.e., N1beta, a correlation is developed for determining the N-ribosyl attachment site of tetrazole ribonucleosides. Results are also presented on antiviral testing of these synthetic 5-aminotetrazole ribonucleosides against influenza A2/Asian/J305 virus infection in mice.


Design of substrate-site-directed irreversible inhibitors of adenosine 5'-phosphate aminohydrolase. Effect of substrate substituents on affinity for the substrate site.

Derivatives of adenosine 5'-phosphate (AMP) have been synthesized in which the phosphoester (POCH2) grouping of AMP is replaced by PCH(R)CH2 where R is OC(O)Me, CH2NHCOMe, CH2NHCOEt, and CH2NHCOOR' (R' = Me, Et, and Pr). The 2',3'-O-isopropylidene and 2', 3'-di-O-acetyl derivatives of AMP were also prepared. All compounds were competitive inhibitors of rabbit muscle AMP aminohydrolase with enzyme-inhibitor dissociation constants (Ki values) of 330, 20, 17, 19, 16, 14, 260, and 105 muM, respectively. All compounds were substrates except those in which R was CH2NHCOEt and CH2NHCOOR' (R'=Me, Et, and Pr). The previously described allo and talo epimers of 5'-C-acetylaminomethyl-AMP and the allo epimer of 5'-C-propionylaminomethyl-AMP were substrates and competitive inhibitors with Ki values of 18, 47, and 42 muM, respectively. The talo epimer of 5'-C-propionylaminomethyl-AMP was not a substrate and was a noncompetitive inhibitor, Ki


Theoretical model-based equations for the linear free energy relationships of the biological activity of ionizable substances. 1. Equilibrium-controlled potency.

Because of the ambiguities of how to treat ionization in empirical equations which relate biological activity to partition coefficient by use of a (log P)2 term, a theoretical approach to the problem is proposed. Based on a simplified view of assays of potency following in vitro or continuous infusion administration of drugs, equations have been derived from a combination of mass law, equilibrium, and extrathermodynamic assumptions. In general form the equations which relate potency to partition coefficient (P) and degree of ionization (alpha) are the following. If the neutral form reacts with the receptor, log (1/C) =-log [1 + SIGMAM(DIPci) + sigman[aj/Pb(1-alpha4y]] + X. If the ionic form reacts with the receptor, log (1/C) =-log [1 + (1 - Alphan)/(alphan)[sigmam(diPci) + sigman[aj/Pb(1-alphaj)]]] + X. In this generalized model there are m nonaqueous compartments and n aqueous compartments of different pH. The parameters a, b, c, and d can be interpreted in terms of the model. The shape of the log (1/C) vs. log P curve may be asymptotic, linear, or composed of two portions of unequal slope which meet at an optimum or a bend. With the use of these equations it is possible to examine whether the ion or the neutral form is the active species and whether there is hydrophobic bonding to the receptor and/or an inert compartment. The models may be further extended to include terms other than log P and alpha.


Quantitative structure-activity relationships. 3.1 A comparison of different Free-Wilson models.

The Fujita-Ban model and the classical Free-Wilson model are shown to be linearly related: the de novo group contributions obtained by one model are linear transformations of those obtained by the other model. An example is given to illustrate this linear dependence. The Fujita-Ban model is characterized by a number of advantages as compared with the classical Free-Wilson model: no transformation of the structural matrix and no symmetry equations are necessary; all group contributions are based on an arbitrarily chosen reference compound, preferably the unsubstituted compound; the constant term, which is the theoretically predicted activity value of the reference compound, and the values of the group contributions are not markedly influenced by addition or elimination of a compound; the problem of linear dependence (the singularity problem) sometimes can be circumvented by preparation of a contracted matrix; if the unsubstituted compound is chosen as reference compound, the group contributions are numerically equivalent to Hansch-derived group contributions; therefore, the Hansch approach and the Fujita-Ban model can be combined to a mixed approach. Taking all these facts into consideration, the Frujita-Ban model is recommended as the most suitable approach for the calculation of de novo group contributions.


(-)-3-Isothujone, a small nonnitrogenous molecule with antinociceptive activity in mice.

(-)-3-Isothujone and (+)-3-thujone were examined for antinociceptive activity using the hot-plate and Nilsen tests. In the hot plate test (-)-3-isothujone (ED50 = 6.5 mg/kg) was found to be codeine-like and equipotent with (-)-delta9-tetrahydrocannabinol while the racemic material was essentially half as potent as the levoratatory isomer. (+)-3-Thujone was inactive in both antinociceptive tests as were several structural analogues of the 3-thujones. As with the THC's less antinociceptive activity was observed in the Nilsen test than in the hot-plate assay. Acute toxicities for the 3-thujones were determined and vastly improved synthetic procedures have been developed for two long-known but difficulty accessible 3-thujanols.


Optical isomers of 2-(2-ethoxyphenoxymethyl)tetrahydro-1,4-oxazine (viloxazine) and related compounds.

The optical isomers of 2-(2-ethoxyphenoxymethyl)tetrahydro-1,4-oxazine (viloxazine) and 2-(3-methoxyphenoxymethyl)tetrahydro-1,4-oxazine have been prepared and absolute configurations have been assigned. In their action on the central nervous system the S isomers are at least ten times more potent than the R isomers. The intermediate 4-benzyl-2-(p-toluensulfonyloxymethyl)tetrahydro-1,4-oxazine has been resolved. Its isomers provide a convenient starting point for the preparation of optical isomers of viloxazine analogues of known configuration.


Synthesis and biological properties of 4-amino- and 4-bromo-4-norpyridoxol. New approaches for the modification of the 4 position of vitamin B6.

4-Amino-4-norpyridoxol, a new key intermediate for the modification of the 4 position of vitamin B6, has been obtained by an unusual photochemical rearrangement of pyridoxal oxime. It has also been synthesized starting from 3,-alpha5-O-dibenzylpyridoxal, which was converted to 3,alpha5-O-dibenzylpyridoxamide. The latter, on Hoffman reaction, gave the desired 3,5-blocked 4-amino derivative. Several derivatives of this analogue have been prepared, and its existence in the amino tautomeric form has been established by NMR spectroscopy. A modified Sandmeyer reaction on 4-amino-4-norpyridoxol gave the 4-bromo analogue, which was found to be moderately active as an inhibitor of mouse mammary adenocarcinoma cells grown in cell culture, whereas the 4-amino analogue was not active at 10(-4)M. Other analogues containing electron-withdrawing and electron-donating substituents in the 4 position of pyridoxine were also tested.


Justice, welfare and health care.

Miss Telfer offers a new analysis, classifying health care into four systems, only one of which, the "laissez-faire" type, is unlikely to be acceptable today. The other three systems are defined here as "liberal humanitarian", "liberal socialist" and "pure socialist." Each is analysed for its content and for the views of its protagonists and antagonists. On these issues no dogma is proclaimed as the author says she has sought to "bring out some of the principles at issue in any discussion of the rights and wrongs of socialized medicine". This journal is surely the proper place for such a discussion as the worlds of the politician, of the economist, of the doctor and of the patient come to a point in the philosophies behind the aspect of medical ethics exemplified in the provision of medical services by the state. Miss Telfer also glances down the byways of the medicine of the market place.


The ethics of animal experimentation.

Animal experimentation arouses great emotion in many people, perhaps more especially in Britain, and this has increased as more sophisticated medical and non-medical animal experiments are demanded by modern research. The Cruelty to Animals Act of 1876 is the only legal regulation of experiments in animals, and many of its clauses are ambiguous. So in 1963 a committee of enquiry - the Littlewood Committee - was set up. Dr Lane-Petter examines the emotional and factual background to the enquiry, and discusses in an ethical context the usefulness and positive advantages of animal experiments compared with those of possible substitutes and in some detail three of the questions left unanswered by the Littlewood Committee.


Exorcism: a psychiatric viewpoint.

Doctors, for several reasons, should be concerned with exorcism is the view of Professor Trethowan, who in this paper, looks at the main features of exorcism as practised in the middle ages and now appearing in the modern world, as was seen in the recent Ossett case in Britain. He examines in some detail the nature of supposed demoniacal possession and describes its symptoms and signs. He also touches on the social, as opposed to the religious, background in which demoniacal possession flourished (not lacking in the world today), so leading to an examination of the psychodynamic aspects of demoniacal possession and the question of absolute evil. Finally he compares the techniques of exorcism and of modern psychiatric practice.


"The soft embalmer of the still midnight": a problem of prescribing hypnotics in general practice.

Was it euthanasia or was it even murder? That is the rather dramatic question with which the case history ends. However, none of those taking part in this conference had any doubts that it was neither murder nor euthanasia. But all had doubts as to whether the patient received the best care which the medical and allied professions can command. The barrister declared that in law there would have been no case to answer but the consensus of opinion of the other participants was that as no real diagnosis had been made the treatment was essentially superficial - ensuring sleep for the patient by prescribing barbiturates. The most fundamental criticism of the management of this patient was that individuals looked after her rather than an interdisciplinary team, some member of which might properly have sought to overrule Dorothy (the patient's daughter) when she took her mother away from a nursing home. However, what makes this case conference fascinating is not the facts of the case or the treatment so much as the avenues for moral and social discussion opened for the reader.


Fluctuation and relaxation analysis of monazomycin-induced conductance in black lipid membranes.

Fluctuation and relaxation analyses were performed on monazomycin-induced conductance of lipid bilayer membranes. With both methods a slow (sec) and a fast (msec) current component are apparent; however, the amplitude of the slow, voltage-dependent process is greater than that of the fast component in the step relaxation experiment and less in the fluctuation experiment. The fluctuation analysis showed principally a rapid voltage-dependent process which appears to be related to the multistate character of the conducting channel. The experimental results are interpreted in terms of a simplified kinetic model which is used to calculate relaxation and noise amplitudes.


2-Deoxyglucose transport by intestinal epithelial cells isolated from the chick.

Characteristics of 2-deoxyglucose uptake (2DG) by intestinal epithelial cells isolated from chickens were evaluated as a means of discriminating between the concentrative transport system for monosaccharides, associated with the mucosal brush border, and other possible routes of monosaccharide entry. 2DG was chosen as it is not a substrate for the mucosal transport system. The deoxysugar enters via a saturable pathway which is not Na+-dependent, is not inhibited by K+, does not accumulate solute against a concentration gradient; exhibits a high sensitivity to inhibition by phloretin; is relatively insensitive to phlorizin inhibition; and has low affinity [but high capacity relative to Na+-dependent mucosal transport of 3-O-methylglucose (3-OMG) and other monosaccharides]. These characteristics confirm those established in an earlier report for Na+-independent uptake of 3-OMG. Complications encountered in the use of 2DG as a test sugar include significant rates of metabolic conversion to an anionic form which presumably is a phosphorylated species. Methods for distinguishing between transport and subsequent metabolism are described. Inhibition of 2DG entry by several other sugars is described and inhibitory constants (K's) given for each.


Effect of transepithelial concentration gradients on the passive fluxes of sodium across toad bladder.

Bidirectional sodium fluxes across toad bladder were measured after eliminating active transport with ouabain. Mucosal sodium concentration, Cm, was progressively reduced (from 114 to 3 mM) while serosal sodium remained constant. Potential difference was maintained at zero by current passage. The ratio, Q, of the bulk permeability coefficient for sodium, P, to the tracer sodium permeability coefficient, P, was found to remain constant as Cm decreased. Equations were derived on this basis for bidirectional fluxes and for P and P as functions of Cm, which corresponded closely to the observed data. The explanation for the observed value of Q and its constancy under these conditions is uncertain.


On the mechanism of electrical coupling between cells of early Xenopus embryos.

The mechanism of electrical coupling between cells of early Xenopus embryos has been studied by examination of the nonjunctional membrane resistances and capacitances as a function of cleavage stage, the junctional and nonjunctional membrane resistances as functions of time during the first cleavage, and the electrical properties of the primitive blastocoel. The changes in membrane resistances and capacitances during the first two cleavages may be completely explained by the addition of new membrane, identical in specific resistance and capacitance to the original membrane, at a constant rate to furrows which are electrically connected to the perivitelline space. Microelectrode recording from the primitive blastocoel indicates that there is no electrical difference detectable between it and the perivitelline space. These results are discussed in the context of current theories of the mechanism of intercellular electrotonic coupling.


The mechanism of Na+ transport by rabbit urinary bladder.

The mechanism of Na+ transport in rabbit urinary bladder has been studied by microelectrode techniques. Of the three layers of epithelium, the apical layer contains virtually all the transepithelial resistance. There is radial cell-to-cell coupling within this layer, but there is no detectable transverse coupling between layers. Cell coupling is apparently interrupted by intracellular injection of depolarizing current. The cell interiors are electrically negative to the bathing solutions, but the apical membrane of the apical layer depolarizes with increasing Isc. Voltage scanning detects no current sinks at the cell junctions or elsewhere. The voltage-divider ratio, alpha, (ratio of resistance of apical cell membrane, Ralpha, to basolateral cell membrane, Rb) decreases from 30 to 0.5 with increasing Isc, because of the transport-related conductance pathway in the apical membrane. Changes in effective transepithelial capacitance with Isc are predicted and possibly observed. The transepithelial resistance, Rt, has been resolved into Ra, Rb, and the junctional resistance, Rj, by four different methods: cable analysis, resistance of uncoupled cells, measurements of pairs of (Rt, alpha) values in the same bladder at different transport rates, and the relation between Rt and Isc and between alpha and Isc. Rj proves to be effectively infinite (nominally 300 k omega muF) and independent of Isc, and Ra decreases from 154 to 4 omega muF with increasing Isc. In the resulting model of Na+ transport in "tight" epithelia, the apical membrane contains an amiloride-inhibited and Ca++-inhibited conductance pathway for Na+ entry; the basolateral membrane contains a Na+--K+-activated ATPase that extrudes Na+; intracellular (Na+) may exert negative feedback on apical membrane conductance; and aldosterone acts to stimulate Na+ entry at the apical membrane via the amiloride-sensitive pathway.


Diffusion and 1/f noise.

The noise associated with ion transport through porous membranes is considered as a diffusion process. This is confirmed experimentally by measuring the noise spectra associated with pores of known dimension. It is then shown that one dimensional diffusion through pores of variable length can produce approximate 1/f noise spectra, if the distribution of lengths is proportional to (length)-1.


Permeability of a cell junction during intracellular injection of divalent cations.

Divalent cations are microinjected into Chironomus salivary gland cells while the cell-to-cell passage of fluorescein (330 dalton) and electrical coupling are monitored. Injections of Ca and Mg that substantially depolarize the cells produce block or marked slowing fluorescein passage, accompanied by electrical uncoupling. Injections of Ca, Mg or Sr that cause little depolarization, and presumably smaller elevation of divalent cation concentration in the cytoplasm, produce block or marked slowing of fluorescein passage with little or no detectable electrical uncoupling. This partial uncoupling may reflect total closure of a fraction of the channels in junctional membrane or partial closure of all channels.


Potassium movement during hyperpolarization of cardiac muscle.

When a bundle of cardiac muscle cells is hyperpolarized, membrane current declines with time. Voltage clamp experiments on sheep and cat ventricular bundles showed that the magnitude of inward current depended on the external K+ concentration. Following prolonged hyperpolarization, membrane current near the resting potential was generally outward. The half-time of decay of this outward current was approximately 2.5 sec at -60mV. The potential measured in the absence of externally supplied current was generally more negative than it would have been without conditioning hyperpolarization. The half-time of recovery of the current response following hyperpolarization was also approximately 2.5 sec at -60 mV, a factor of approximately 3.7 slower than the preceding decline of inward current. The rate of recovery has only a slight temperature dependence (Q10 approximately equal to 1.2). The experimental results are consistent with the idea that during hyperpolarization K+ is depleted from approximately 3% of the total muscle volume, and that the replenishment of K+ occurs primarily by K+ diffusion from a much larger fraction of the extracellular space.


Mutants with reduced Ca activation in Paramecium aurelia.

Two heat-sensitive "pawn" mutants of Paramecium aurelia are capable of avoiding reactions when grown at 23 degrees C but not at 35 degrees C. Electrophysiological analyses show that Ca activation is reduces in the mutants even when they are grown at 23 degrees C. The maximal rate of rise and the peak of the evoked action potential (Ca-spike) in the mutants are smaller than those of wild type in a K-solution. After suppression of K conductance by either TEA+ or Ba++, the action potentials of the mutants peak at the same level as that of wild type. However, the maximal rate of rise of the mutants remains only about half that of wild type. Thus, the mutations affect Ca activation but not K activation. Incubation at a high temperature (35 degrees C) further reduces Ca activation to almost zero in the mutants but has little or no effect on wild type. This almost complete loss of Ca activation explains the lack of avoiding reactions when the mutants are grown at high temperatures. A double mutant containing two heat-sensitive mutations shows extremely reduced Ca activation even when grown at 23 degrees C.


Effects of continuous light and darkness on the eyes of the troglobitic salamander Typhlotriton spelaeus.

Larval Typhlotriton spelaeus collected from five caves in Pulaski Co., Missouri, were kept as larvae or induced to transform in darkness or continuous fluorescent illumination. Larvae maintained in darkness for 215 and 279 days had smaller eyes, smaller rod inner and outer segments, and fewer metaphase figures in the germinative zone of the neural retina than comparable larvae maintained in light (258 lux). Except for visual cell size, differences were small and for each characteristic exceptions were observed. One larva kept in light showed early retinal degeneration comparable to that in transformed adults to T. spelaeus. All larvae exhibited optomotor behavior both before and after the experiment. Among animals induced to transform by L-thyroxin and maintained in darkness 111 to 366 days, visual cell and pigment epithelium degeneration was more extensive and more frequent than in animals kept for the same length of time in light (237-298 lux). In darkness the frequency of animals with retinal degeneration increased between 111 and 366 days. In light some animals exhibited pigment epithelium reduction with normal visual cells, and others had free, pigmented cells in the subretinal space. These effects were not comparable to degeneration in darkness. Eyelids covered the eyes of only a few animals in both light and dark treatments. The extent of eyelid encroachment over the eye greater in darkness than in light. Most animals exhibited optomotor responses after experiments, but responses of animals kept in darkness were impaired in comparison to those of animals kept in light.


A staging system for forelimb regeneration in the axolotl, Ambystoma mexicanum.

A staging system has been devised for normal regeneration from the upper arm in the mature axolotl. It consists of seven externally definable stages: (1) Wound healing (WH): (2) Dedifferentiation (DD); (3) Early bud (EB); (4) Medium bud (MB); (5) Late bud (LB); (6) Palette (Pal), and (7) Digital outgrowth (DO). Serial histological sections of 38 regenerating limbs were used to correlate gross stages with microscopic events in the regenerative process.


Cytological observations of the ovarian epithelium in mammals during the reproductive cycle.

We have studied the ovarian epithelijm at various stages of the reproductive cycle in a number of mammalian species utilizing light microscopy, scanning microscopy, the freeze-fracture technique, transmission microscopy and by employing specialized tracers that use lanthanum and horseradish peroxidase. We found that the epithelial cells are joined by incomplete tight junctions, gap junctions, and desmosomes. The cytoplasmic matrix contains a large irregularly shaped nucleus, few microtubules, microfilaments, mitochondria, endoplasmic reticulum and a host of coated and non-coated vesicles of varying diameters. The saccules comprising the large Golgi complex and its companion vesicles are associated with a basal body-centriole complex: some of these saccules and affiliated vesicles are acid phosphatase positive. Surface modifications of ovarian epithelial cells include numerous microvilli, some of which have a bulbous tip, and plications of the lateral plasma membrane which are thought to accomodate volume changes of the ovary during follicular development. Many coated and non-coated endocytotic caveolae were found on these cells, particularly in the basal area. These caveolae internalized exogeneously administered horseradish peroxidase. We view the marked endocytotic activity as an efficient transport mechanism for partially removing substances from the interstitium of the ovary and the peritoneum.


Ultrastructure of the secretory cells of the submucosal glands in the human maxillary sinus.

Tissue samples obtained from the lateral wall of the maxillary sinuses of five patients were examined by light microscopical, histochemical, and ultrastructural techniques. Submucosal glands were tubulo-alveolar mixed glands. The acini consisted of either all serous or all mucous cells, or a mixture of both. Serous granules were stained by toluidine blue, or by hematoxylin and eosin (H and E), but showed little or no reaction with periodic acid-Schiff (PAS) or Alcian blue. Mucous granules were pale in toluidine blue or H and E preparations, and consisted primarly of acid mucosubstances, as demonstrated by their staining reaction with PAS and Alcian blue. At the electron microscope level, the serous granules were either homogeneously dense, or showed a substructure consisting of at least two layers of distincly different electron-opacity. Typical mucous droplets consisted of a fibrillar network dispersed in a translucent matrix. A second secretory product was present in the mucous cells in the form of elongated, membrane-bounded structures containing numerous parallel filaments, which measured about 55 A in diameter. The mucous droplets and the filamentous bodies appear to arise from the opposite faces of the Golgi complex in the mucous cells. The filamentous bodies showed a pronounced tendency to fuse with the mucous droplets. All acini were surrounded by a well-defined myoepithelial layer and contained intercellular nerve terminals.


Fine structure of the retinal epithelium and tapetum lucidum of the opossum (Didelphis virginiana).

The fine structure of the retinal epithelium has been studied by electron microscopy in the opossum (Didelphis virginiana). The retinal epithelium, over most of the retina, is typical of that in other vertebrates and consists of a single layer of heavily pigmented, cuboidal cells. These cells display extensive basal (scleral) infoldings and numerous apical (vitreal) processes which enclose photoreceptor outer segments. A semicircular area of the retinal epithelium in the superior fundus is further specialized as a tapetum lucidum. The reflecting material consists of a large quantity of lipoidal spheres scattered throughout the epithelial cells. Centrally in the tapetal area very few or no melanosomes are found, indicating a non-occlusible tapetum. Peripherally in be tapetum, the epithelial cells contain both reflecting material and melanosomes. As in the non-tapetal area, the epithelial cells of the tapetum display large amounts of smooth endoplasmic reticulum and numerous mitochondria. Bruch's membrane everywhere displays the usual pentalaminate structure described for most vertebrates. The choriocapillaris is also typical, in that numerous fenestrations are present in the endothelium bordering Bruch's membrane.


The structure of the hypothalamic inferior lobes of the blacktip reef shark: scanning and transmission electron microscopic observations.

The inferior lobes of the shark hypothalamus were examined with light, transmission and scanning electron microscopy. The cells bordering the floor of the lateral recess appear to be typical liquor-contacting neurons. With scanning electron microscopy (SEM) the apical ends of these cells are seen to bulge into the ventricular lumen. In contrast, the roof is lined by a more typical ependymal cell characterized by numerous cilia and microvilli. In addition, SEM reveals several kinds of supraependymal cells with processes that appear to penetrate the ventricular lining. A periventricular nucleus underlies the ependymal cells. Neurons of the periventricular nucleus contain numerous lipofuchsin granules. The rest of the inferior lobe consists of many neuronal fibers. The morphology of the hypothalamic inferior lobe is discussed in relation to its possible role in feeding and aggressive behavior in both elasmobranchs and teleosts.


Self complementarity in messenger RNA of collagen. I. Possible hairpin structures in regions coding for oligopeptides of glycine, proline (hydroxyproline) and alanine.

The periodic protein collagen is of special interest for the study of the relationship which exists between the structure of a protein and that of its mRNA, because oligopeptides containing glycine, proline (hydroxyproline) and alanine occur with great frequency in it. Collagen is particularly rich in these amino acids, which have codons containing only G and/or C in the obligatory first and second positions. If unlimited choice of codons for all amino acids were to occur, the stretch of mRNA coding for an alpha-chain should contain about 40% G and 31% C (Bachra et al., 1974). These high values suggest that a considerable degree of secondary structure will occur, unless selective codon use would result in the avoidance of G and C in optional third codon positions. In the present paper putative secondary structure formation in collagen mRNA was studied. This was done by studying the positions and frequencies of hairpin structures which could contain stem sections composed of the coding triplets of the above mentioned amino acids and hairpin sections of 4-40 bases. Calculation of the free energy contributions of such hairpin structures, using published values for the contributions of base-pair stacking, hairpin, bulge and interior loops and also taking into account the possible minimum number of base-pairs required for helix nucleation from a single-strand RNA (3 adjacent AU-pairs or 1 or 2 adjacent GC-pairs) led to the following conclusions. A considerable number of alternative, mutually exclusive hairpins can be constructed.


Elemental abundance as a factor in the origins of mineral nutrient requirements.

No element is found to be commonly required if it has an abundance of less than about 2 nM in the ocean, 20 mumoles/kg in the earth's crust, or 200 mumoles/100 moles Si in the cosmos. More than 40 elements are above these limits, but only 18 of them are commonly required (6 of these being dispensed with by some organism). It is postulated that all of the required elements fall under one of four hypotheses: H-I--a unique requirement dating from the origin of life; H-II--a unique requirement, acquired later; H-III--a primordial requirement which was satisfied by a number of elements, evolutionary adaptation being made to the most abundant member; H-IV--same as III, but a later acquisition. It is suggested that H, K (vs. Na), Mg (vs. Ca), C, N, O, P, S and Fe fall under H-I. Special requirements such as for B, Se and I fall under H-II. In H-III are K vs. Rb, Mg vs. Be(?), S vs. Se, Clvs. Br, H vs F(?), and Zn and Mn vs. various metals. In H-IV probably fall Ca vs. Sr, Na vs. Li (?), Mo vs. V, and Si vs. Ge. The most abundant heavy metal in the ocean is Zn, which may account for its utilization; other required heavy metals have special utility as electron carriers.


Criteria for optimising phylogenetic trees and the problem of determining the root of a tree.

The process of determining the optimal phylogenetic tree from amino acid sequences or comparable data is divided into six stages. Particular attention is given both to the criteria that are used when testing for the optimal tree and the problem of determining the position of the original ancestor. Four types of criteria for evaluating the optimal tree are considered: 1. parsimony (fewest total changes), 2. path lengths from an ancestor to existing species, 3. subtracting the difference between each pair of species as measured on the tree and as compared directly with the data ("excess differences"), 4. Moore Residual Coefficient. These criteria are examined on a set of test data and some of the reasons for the differences among them are discussed. For example, the "average percent standard deviation" weights excess differences unequally in inverse proportion to the square of the observed differences. The Moore Residual Coefficient and the "excess differences" will not necessarily give a value of zero when there are no duplicated changes unless there can only be two states for each character (i.e. binary data). The path length and difference criteria (as well as the Moore Residual Coefficient) give unequal weighting to the individual branches of the tree by counting some branches more times than others. Particularly because of this some criteria will reject trees that are equally parsimonious and the criteria are said to be invalid. However the criterion of parsimony is insensitive in that it can give the same value for several basic networks and it does not specify the position of the original ancestor, the root of the tree. The importance is emphasised of stating a model and examining its predictions before a criterion is chosen to select the best network. The number of rooted trees that can be derived from a basic network (or unrooted tree) is described in relation to how detailed a description of the original ancestor is required. Four methods are described for determining the position of the root of the tree or original ancestor. Each method depends upon some additional information to that used in constructing the basic network and the method chosen will depend on this additional knowledge.


Arsenic and cancer: the still unanswered question.

For some 2,500 years, arsenic was considered an important element of pharmacopeias and was praised for its medicinal qualities. However, an incidental link with cancer was suggested during the nineteenth century, and since that time a controversy has ensued with regard to the compound's tumorigenicity. Several epidemiological surveys, for example, have suggested that arsenic induces lung, liver, or skin cancer in humans. On the other hand, all experimental attempts to reproduce such neoplasms in laboratory animals have consistently failed, thereby denying support to the human data. Recently arsenic was reported to be mutagenic. However, because of the inconsistency of most mutagenesis findings at present, this also cannot be regarded as supporting evidence. Furthermore, a recent trend has been to consider arsenic as beneficial in cancer prevention and in maintaining the health of farm animals, and, perhaps, humans. A critical review of epidemiological and experimental data from the literature has been made in an attempt to present an objective picture of this controversial and sensitive question and to encourage further research, which may ultimately determine whether arsenic deserves its execrable reputation.


Effect of acute carbon monoxide poisoning on serum lactate dehydrogenase and creatine phosphokinase.

Young adult rats were exposed to 1,500 ppm CO in air for 2 hr. Blood carboxyhemoglobin (COHb) concentration immediately postexposure was 55.68 +/- 0.90%. Serum lactate dehydrogenase (LDH) activity peaked at 117% above control 2 hr postexposure, while serum creatine phosphokinase (CPK) activity was maximal at 132% above control immediately following termination of exposure. Serum LDH activity declined to control within 8 hr, while serum CPK undershot controls at 8 hr and returned to the control value by 24 hr.


A study of chromosomes of schistosomiasis patients under oxaminiquine (UK 4271) treatment.

Blood samples from 24 patients infested with Schistosoma mansoni were drawn immediately before and 2 days after the administration of a single therapeutic dose of 12-15 mg/kg oral oxaminiquine. Two-day lymphocyte cultures were obtained and about 100 mitoses from each blood sample were analyzed for chromosome aberrations. No significant differences were observed between the "before" and "after" cultures in the frequencies of aberrations resulting from spindle, chromatidic, or chromosome events. It is concluded that there is no reason to fear harmful effects on the chromosomes of patients from treatment with oxaminiquine.