Effect of tolbutamide on aminophylline-, 3,5-AMP-dibutyrate- or glucagon-induced insulin release from pancreatic islets after impairment of pyridine nucleotide metabolism caused by 6-aminonicotinamide (6-AN).

The effect of tolbutamide on pyridine nucleotides and insulin secretion stimulated by aminophylline, 3,5-AMP-dibutyrate or glucagon was studied in pancreatic islets of rats previously treated with 6-aminonicotinamide (6-AN), an inhibitor of pyridine nucleotide synthesis. After being incubated for 60 min in a Krebs-Ringer-Bicarbonate-Buffer in the absence of glucose, pancreatic islets of rats i.p. injected with 35 mg/kg of 6-AN 6 hrs before pancreas removal contained about 30% less NADP and NADPH than did islets of control rats. No changes of NDA or NADH were observed in islets of 6-AN-treated animals. Addition of 16.5 mM glucose led to an increase of NADH, NADPH and a decrease of NADP in islets of both groups of animals; NAD levels remained unchanged. In vitro addition of tolbutamide to islets of control rats did not affect the levels of NADPH or NADP in the presence of 5.5 mM glucose. When 16.5 mM glucose were present, a decrease of NADPH and an increase of NADP was obvious. No effect of tolbutamide on insular NADPH or NADP was observed in islets of rats previously treated with 6-AN be it in the presence of 5.5  or 16.5 mM glucose. In islets of 6-AN-treated rats insulin release in response to aminophylline or 3,5-AMP-dibutyrate in the presence of 5.5 mM glucose was significantly depressed, when compared to islets of untreated controls. Addition of tolbutamide increased insulin release due to aminophylline, 3,5-AMP-dibutyrate or glucagon islets of controls. Tolbutamide alone was without effect. In islets of 6-AN-treated rats aminophylline, 3,5-AMP-dibutyrate or glucagon stimulated insulin release only when tolbutamide was present. Our data suggest that there is no direct interference of tolbutamide with pyridine nucleotides of pancreatic islets, and that tolbutamide increases the secretory response of the beta-cell to aminophylline, 3,5-AMP-dibutyrate or glucagon when insulin release due to these agents is inhibited during decrease of insular NADP and NADPH, caused by 6-AN.


Effects of arecoline and cholinesterase inhibitors on cyclic guanosine 3',5'-monophosphate and adenosine 3'.5'-monophosphate in mouse brain.

In mice, Arecoline in vivo dose-dependently increased the cGMP concentrations of the cerebellum and the "cereberum" (= parts of cortex, hippocampus, hypothalamus, thalamus, striatum and midbrain) without influencing thecAMP levels. The cholinesterase inhibitors paraoxon and physostigmine caused an elevation only in "cerebrum", whereas the cGMP content of the cerebellum even decreased. Pretreatment with atropine prevented the rise in cGMP levels as well as the symptoms of cholinergic stimulation elicited by arecoline or paraoxon. Diazepam reduced cGMP levels below control values and blocked the effect of arecoline, while typical symptoms due to arecoline, e.g., tremor and salivation remained unaffected. The tripeptide prolyl-leucyl-glycinamide (MIF) had no effect on either cGMP values or the peripheral signs of cholinergic stimulation elicited by arecoline. The results show that elevation of cGMP in the central nervous system caused by cholinomimetic agents can be prevented not only by cholinolytics, blocking muscarinic receptors but also by influencing other mechanisms to be discussed.


The autoregulatory capability of Galen's rete cerebri and its connections.

The rete, a vascular system between the extra- and intracerebral arteries of certain animals, may have a variety of functions in different species. The calibres of the vessels of the rete and its arteries of supply have been measured under different conditions of blood pressure and PaCO2. It has been shown that the rete and its afferent arteries behave in an autoregulatory fashion down to a blood pressure of 60 mmHg. They also dilate with a rise in PaCO2. It has also been found that some parts of the system dilate even when the blood pressure drops lower than 60 mmHg. It is suggested that this autoregulatory capacity of extradural vessels limits the requirement for CSF spaces to change with blood pressure changes. A general rule has been sought which would link the known facts about cerebral autoregulation and the possession of extra- to intracranial anastomoses with the bodily shape and posture of the particular animal.


Infantile Gaucher's disease: glucocerebrosidase deficiency in peripheral blood leukocytes and cultured fibroblasts.

A patient with infantile Gancher's disease is described. A marked decrease of the activity of beta-glucosidase at the lower pH 4.2 was found in peripheral blood leukocytes, whereas in cultured skin fibroblasts the activity at both pH'S 4.2 and 5.2 was decreased. Examining the leukocytes of the heterozygous parents the activities of beta-glucosidase at both pH's were within the values of controls, but the ratio's of activity of pH 5.2 to that at pH 4.2 were increased lying between the ratio's from the patient and controls.


[Metabolic alkalosis. Compensation mechanisms in the light of new experimental data].

Changes in arterial blood and erythrocyte acid-base and electrolyte balance in the course of acute alkalinisation caused by bicarbonate loading showed that extracellular alkalosis has no significant effect on the concentration of intraerythrocyte bicarbonate concentration, though a marked increase in pH and electrolyte balance within the red cell is apparent. Erythrocyte alkalinisation may thus be seen as essentially due to the escape of H+ ions, while the entry of Na+ ions is the main device by which the law of electroneutrality is respected. The literature suggests that lactic acid offers a source of H+ ions for destruction of bicarbonate, whereas the diffusion of the ion lactate within the cell is compensated by the release of Cl-. In addition, the data now reported indicate that the red cell is a sufficiently valid model for the study of phenomena occurring within the intracellular compartment when a state of extracellular alkalinisation in created.


[Current evaluation of beta-adrenergic agents in the treatment of bronchial spasm].

The current status of beta-adrenergics in the treatment of bronchospasm is discussed. Personal experience is reviewed with special attention being paid to associations of the drugs on aminophylline, atropine and bechlomethasone dipropionate.


[Treatment of enuresis with Noveril].

The authors present their observations on treatment with Noveril of nocturnal enuresis in 49 children aged from 6 to 16 years. The drug is a derivative of dibenzodiazepine belonging to the group of thymoleptic agents with an action similar to that of imipramine. Noveril was given in doses from 20 to 100 mg daily during 3 to 9 weeks. In the final evaluation of the drug the frequency of enuresis before, during and after treatment was taken into account. In 25 cases an improvement was observed, usually in psychogenic nocturnal enuresis. Side effects included oral dryness, headaches and dizziness, and sleep disturbances observed in 4 cases. The tolerance of the drug was good. Noveril has a favourable effect in children with nocturnal enuresis, particularly of psychogenic origin.


Strontium, lead and nickel incorporation into mouse calvaria in vitro.

Incorporation of strontium, lead and nickel radioisotopes was studied in mouse calvaria in tissue culture. About 90% of the incorporated strontium and 5-12% of the lead were recovered in the mineral phase of the calvaria (hot acid soluble fraction), whereas the nickel was recovered mainly in the organic phase (hot alkali soluble fraction). Metabolic inhibition enhanced the incorporation, which indicated that the mineral metabolism of the calvaria comprised ionic exchange or secondary mineralization phenomenons independent of the activity of bone cells but, possibly, guided by a metabolically active bone membrane.


Persistent and transient distal renal tubular acidosis with bicarbonate wasting.

Bicarbonate titration studies were performed on two patients with bicarbonate wasting distal renal tubular acidosis (RTA; patients 1 and 2) and on three patients (3,4, and 5) with classic distal RTA. Daily requirements of alkali were 4.5 mEq/kg body wt in patient 1, a 3-year-old boy, and 16 mEq/kg in patient 2, a 5-month-old male infant. In contrast, only 1.5-2 mEq/kg/24 hr alkali were required in the three patients with classic distal RTA (age 8 1/2- 22 years). Patient 1 had glucose-6-phosphate dehydrogenase deficiency and patient 3 had inner ear deafness as an associated anomaly. In patient 2, the acidification defect was transient. Mean fractional excretion of bicarbonate (ChCO3-/Cin) times 100 at a plasma concentration of HCO3 below 20 mmol/liter was 5.1% in patient 1, 11.6% in patient 2, and 1.7% in patients 3-5. Minimal urine pH during the study was 7.38 in patient 1, 7.66 in patient 2, and 6.78-6.97 in the other patients. Values of net acid excretion at plasma HCO3 = 16 mmol/liter were strongly negative in patients 1 and 2 (-75 and -195 mumol/100 ml glomerular filtrate (GF), respectively) but slightly positive in the three patients with classic RTA (+3 to +20 mumol/100 ml GF). The two patients with bicarbonate wasting distal RTA were thus clearly separated from the group of patients with classic distal RTA.


Bilirubin interaction with ganglioside: possible mechanism in kernicterus.

Reaction of bilirubin with increasing amounts of ganglioside purified from neonatal brain significantly alters the spectral absorption of bilirubin in proportion to the quantity of ganglioside added. Increments in absorbance occur at 353 nm with a prompt but transient increase at 486 nm. A decrease in absorbance occurs which is most marked at 447 nm. When gangliosides are added to bilirubin (9.1 mug/ml or 0.016 muM/ml), the decrease in absorbance is essentially linear up to the highest concentration of purified ganglioside tested (182 mug/ml or 0.097 muM/ml), which represents a molar ratio of 6.1:1. The asymptotic nature of the bilirubin-ganglioside reaction as measured by the decrease in absorbance with time suggests a stoichiometric relationship between the two substances. An isosbestic point was demonstrated at 405 nm. Observations reported here suggest bilirubin reaction with ganglioside is at least a two-step process.


Effect of beta-adrenoreceptor stimulants on exercise-induced asthma.

Exercise-induced asthma can be prevented or minimized by beta-adrenoreceptor stimulating drugs, which may elicit bronchodilation before exercise has begun or may enhance thebronchodilating effect of more prolonged exercise. Recently introduced beta-adrenoreceptor stimulants have longer durations of action than isoproterenol, are effective following oral administration, and are selective for beta-adrenoreceptors.


Exercise-induced asthma and competitive athletics.

Although swimming is their optimum sport and exercise, asthmatics should be encouraged to embrace a full and varied program of sport and physical education. Sports exclusion should be infrequent as possible. Pre-exercise cromolyn sodium with significantly reduce exercise-induced asthma (EIA) and salbutamol may be administered pre-exercise should EIA supervene. "Warm-up" is recommended. The current ruling which classes selective beta2-adrenocepter agonists as doping agents in sports should be rescinded.


Kinesthetic figural aftereffects in acute schizophrenia: a style of processing stimuli.

The Kinesthetic Figural Aftereffect test was administered to 106 psychiatric inpatients to assess styles of stimulus processing in schizophrenia. Three conditions were used: (1) standard stimulus conditions at the acute phase; (2) standard conditions, 7 wk. later, to evaluate stability over time; (3) reversed stimulus conditions to assess kinesthetic figural aftereffect generality under different stimulus conditions. Results indicated that: (1) schizophrenics reduced stimuli, but differences between patient groups were not significant. (2) Kinesthetic figural aftereffect stability over time was shown by nonschizophrenics (p less than .01) but not by schizophrenic and borderline patients. (3) All diagnostic groups reversed kinesthetic figural aftereffect responses under reversed stimulus conditions, e.g., former "augmenters" tended to reduce more under agumenting conditions, suggesting the importance of the specific stimulus conditions. (4) Acute schizophrenics showed a stimulus-governed style. (5) The results raise questions about kinesthetic figural aftereffects as a measure of response style.


Use of mental imagery in psychotherapy: a critical review.

The paper presents arguments in favor of the use of mental imagery for therapeutic purposes. Several existing imagery approaches to psychotherapy are critically examined and suggestions for future inquiry are offered. The intimate relation between imagery and the affective-somatic processes is stressed.


The effects of calcium and magnesium on inhibitory junctional transmission in smooth muscle of guinea pig small intestine.

The membrane potential of smooth muscle cells in the circular layer of the guinea pig ileum was recorded using intracellular electrodes. Transmural stimulation, in the presence of atropine, caused a transient hyperpolarization, an inhibitory junction potential (IJP). IJP's are thought to result from the action of transmitter released from intramural inhibitory nerves. It has been reported that, in the guinea pig jejunum, the amplitude of the IJP resulting from field stimulation is not altered by changes in the calcium and magnesium ion concentration in the bathing solution. Experiments reported here have shown that the IJP amplitude decreased markedly on reducing the calcium ion concentration and or increasing the magnesium ion concentration. Indirect evidence is presented suggesting that the decrease in amplitude of the IJP is due to a decrease in the amount of transmitter released.


[Effect of potato starch on the level of volatile fatty acids and ammonia in sheep's rumen].

Two experiments were performed on adult sheep, which were given intraruminally potato starch in a single dose of 1500 g and in gradually increasing doses. The effect of starch on the level of volatile fatty acids, ammonia and the pH value was studied. In the rumen content, the level of pH slightly decreased and that of volatile fatty acids increased. Ammonia level decreased after starch administration. No lactic acid was found in the rumen content.


The influence of dopamine-beta-hydroxylase inhibitors on avoidance reaction in rat.

Dopamine-beta-hydroxylase inhibitors sodium diethyldithiocarbamate (DEDTC), disulfiram (DS), sodium dimethyldithiocarbamate (DMDTC), tetramethylthiuram disulfide (T) and alpha,alpha'-dipyridyl (DP) were studied for their influence on avoidance reaction in rat. These compounds were given in the doses inhibiting noradrenaline synthesis (decreasing the level of this amine in brain). They all inhibit avoidance reaction although certain differences were stated in the values of effective doses and in the power of action. DEDTC, DMDTC and DS appeared to be most effective. The results of experiments suggest that noradrenaline in brain has significant importance for the avoidance reaction in rats, similarly as it is assumed for dopamine.


Effect of nitrite on the phosphorolytic and hydrolytic glycogen decomposition in the heart and skeletal muscle.

Sodium nitrite produces indirectly an increase in glycogen phosphorolysis and hydrolysis both in the working heart muscle and in quiescent skeletal muscle. The results indicate this effect being related to catecholamines liberation as it never occurs after adrenalectomy, reserpine administration or beta-receptor blocking. The most significant effect of nitrite and adrenalin interaction consists in abolition of inhibiting influence of adrenalin upon glycogen hydrolysis which leads to significant increase in contribution of unphosphorylated sugars to the total pool of products liberated in a course of enhanced glycogenolysis process in the heart.


Potentiometric determination of theopaverin components in nonaqueous media.

Potentiometric method for determination of papaverine hydrochloride (PAP) and theobromine (Tb) in a mixture, without separation of the components was designed. Determinations were carried out in nonaqueous media, using solvents differentiating the strength of estimated bases.


IR analysis of crystalline samples of some urea derivatives.

The dependence of an IR spectrum of crystal samples of allantoin, barbital, chloroethylaminouracil (dopan), carbromal, 5-allyl-5-(beta-hydroxypropyl)-barbituric acid (ipronal) and theophyllin upon the method of crystals preparation was found after 3 months storage of crystals. There were no differences in the case of mephenytoin. The results obtained here demonstrate the possibility of an occurence of the majority of the analyzed substances as metastable polymorphic modifications in solid dosage forms. Furthermore, the IR identification of drugs requires crystallization of a substance from a particular solvent just before analysis.


[Value of the determination of gamma glutamyl transpeptidase in the detection of hepatic metastases of bronch-pulmonary cancers].

The authors have dosed gamma glutamyl transpeptidase in 42 patients with primary bronchopulmonary cancer, of whom 14 had liver metastases. In these 14 patients the level of gamma glutamyl transpeptidase was always high, except in 1 case; while in the remaining lot, a moderate and mostly belated increase was noticed in only 32 percent of cases. The dosing of gamma glutamyl transpeptidase present some interest in the detection of liver metastases in primary bronchopulmonary cancers, specially when coupled with the dosing of alcaline phosphatase. Interpretation of results should take into account the existence of an associated liver-gall bladder involvement and of a recent surgical operation; both factors being capable of raising the level of gamma glutamyl transpeptidase.


[Activity of certain dehydrogenases in accumulation and continuous-flow culture of paraffin-oxidizing yeast of the genus Candida].

Lability of NADP- and NAD-dependent glutamate dehydrogenases and malate dehydrogenases has been demonstrated during a change of the physiological activity of yeast Candida guilliermondii in the exponential phase of growth. Variations in the isoenzyme spectrum of the enzymes and total dehydrogenase activity of the yeast has been found during their transition from the accumulative to the continuous cultivation. Changes in the physiological state of yeast during their growth are accompanied by a rearrangement of the isoenzyme spectrum of malate dehydrogenase and glutamate dehydrogenases.


[Effect of temperature and the active acidity of the medium on the metabolism of reserve carbohydrates and the survivability of baker's yeast].

The effect of the cultivation temperature and active acidity of the medium on the contrent of trehalose and glycogen in baker's yeast was investigated. With the temperature growth from 20 to 40 degrees C the trehalose content in the cells increased, thus enhancing survivability of yeast during storage. The same results were observed upon temperature rise at the end of cultivation. pH of 4.5-5.0 intensified the synthesis of both reserve carbohydrates in baker's yeast.


[Torula thermophila, strain UzPT-1 a thermophilic producer of proteolytic enzymes].

The properties of the thermophilous fungus Torula thermophila producing proteolytic enzymes are described. Oprimal conditions for its cultivation are established. The maximum action of the preparation isolated from the culture liquid filtrate is at pH 9-11. The temperature maximum of the enzyme activity is 70 degrees C.


[Stableness of the alkaline protease of the fungus Torula thermophila strain UzPT-1 to heating and the action of Ca2+ ions].

Thermal stability of protease of the fungus Torula thermophila strain UzPT-1 was examined. The dependence of this property on the content of monomer and dimer forms in the preparation was also investigated. The preparations with a high content of the dimer form showed greater thermal stability in distilled water. The preparations/with the predominant monomer from retained thermal stability in buffer solutions at pH 8 and lost it in distilled water when stored in the cold (2-4 degrees C) for several days. The preparations which lost thermal stability upon ammonium sulphate precipitation recovered partially or completely after addition of Ca2+ ions at a concentration of 0.001 M.


[Separation and characteristics of the proteolytic enzymes of Bacillus subtilis].

The composition of two protosubtilins -- proteolytic enzymes of the enzymes isolated from submerged cultures of two Bacillus subtilis strains was investigated. Each of the preparations contained two proteinases that differed in their pH optimum. Conditions of chromatographic separation of two proteinases on CM-52 cellulose were tested. With the use of specific inhibitors and specific substrates it has been shown that one of the proteinases belongs to metal enzymes and is inhibited by ethylene diamine tetracetate (EDTA). Another proteinase, which is probably serine proteinase, is inhibited by diazopropine fluorophosphate (DFP). The isoelectric point of neutral proteinase is 8.15-8.20.


[Separation and characteristics of the acid proteinases from a surface culture of Aspergillus terricola].

The enzymic preparation isolated by ethanol precipitation from the aqueous extract of the surface culture of Aspergillus terricola was purified on biogel P-10, fractionated on SE-Sephadex. As a result, 10 fractions of acid proteinases that differed in pH optima and activity were obtained. After purification specific activity of some fractions per 1 mg protein increased 24-32-fold. The temperature optimum of the enzymes was at 50 degrees C and pH optimum at 2.5--2.8.


Receptor-dependent hydrolysis of cholesteryl esters contained in plasma low density lipoprotein.

Selective radioactive labeling of the cholesteryl esters contained within human plasma low density lipoprotein has allowed the study of the metabolism of these molecules in monolayers and extracts of cultured human fibroblasts. In monolayers of normal cells, binding of low density lipoprotein to its cell surface receptor was followed by rapid hydrolysis of the [3H]cholesteryl linoleate contained within the lipoprotein and accumulation of the liberated [3H]cholesterol within the cell. The stoichiometry of the degradative process suggested that the protein and cholesteryl ester components of the lipoprotein were hydrolyzed in parallel. Incubation of intact fibroblasts with chloroquine, a known inhibitor of lysosomal degradative processes, inhibited the hydrolysis of the lipoprotein-bound cholesteryl esters. Fibroblasts from subjects with the homozygous form of familial hypercholesterolemia, which lack functional low density lipoprotein receptors and thus are unable to take up this lipoprotein when it is present in the culture medium at low concentrations, were therefore unable to hydrolyze the lipoprotein-bound [3H]cholesteryl linoleate. However, cell-free extracts from these mutant cells were capable of hydrolyzing the lipoprotein-bound [3H]cholesteryl linoleate at the same rapid rate as normal cells when incubated at acid pH. These data illustrate the essential role of the low density lipoprotein receptor and of lysosomal acid hydrolases in the metabolic utilization of low density lipoproteins by cultured human fibroblasts.


ATP, cyclic AMP, and magnesium increase the affinity of rat striatal tyrosine hydroxylase for its cofactor.

Treatment of rat striatal tyrosine hydroxylase [tyrosine 3-monooxygenase; L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating); EC 1.14.16.2] with conditions optimal for protein phosphorylation results in the reduction of the tyrosine hydroxylase Km for the cofactor 6-methyltetrahydropterin from 0.50 mM to 0.16 mM. This reaction is dependent upon ATP, 3':5'-cAMP, and Mg++ and causes a marked decrease in the sensitivity to end-product inhibition. Other brain regions and the adrenal gland show a similar response.


[Production and properties of a beta-galactosidase preparation from Alternaria tenuis].

Different methods of the preparation of fungal beta-galactosidase from the 72-hour culture of Alternaria tenuis were tested: lyophilization of the culture liquid, precipitation with ethanol, acetone, ammonium sulphate. Optimal results were obtained with precipitation by 1.5 acetone volume. Studies of the properties of fungal beta-galactosidase demonstrated that the preparation retained its activity during 22 month storage at 5 degrees C. The fungal preparation had pH optimum at a more acidic zone (4.2 versus 6.9), was active in a wider pH range 2.8-5.7 and 6.2-7.5), had a much higher temperature optimum (65 degrees and 30 degrees) and better thermostability as compared with the yeast preparation. Data on other properties of the preparation are presented.


[Formation of dextranases by mycelial fungi and actinomycetes].

The dextranase activity of cultures of mycelial fungi of different genera and actinomycetes from the Chromogenes species of the Actinomyces genus was studied. About one third of the mycelial fungi and 8% of actinomycetes showed dextranase activity. The resulting extracellular dextranases demonstrated on endotypic pattern of action on the substrate. Actinomycete dextranases were several times more active than fungal dextranases and exhibited a significant activity in the neutral and weakly alkaline medium. Highly productive strains that are promising as dextranase producers were isolated.


Stabilization of electron spin resonance probes for photosynthesis studies.

The major obstacle to the study of functional/structural interrelationships of spinach chloroplasts by using spin labels has been the rapid loss of the electron paramagnetic resonance (EPR) signals upon illumination with visible light. The present study demonstrates that the addition of ferredoxin and NADP+ in the presence of N-tris(hydroxymethyl)methylglycine (Tricine) buffer at pH 7.1 or higher mitigates the rapid loss of Biradical X [N,N'-bis(1-oxyl - 2,2,5,5 - tetramethylpyrroline-3-carboxy)-1,2-diaminoethane] and Monradical A (2,2,5,5-tetramethyl-3-carbamidpyrroline-1-oxyl). However, the 5-line EPR spectrum characteristic of Biradical X in aqueous solution was changed to a dominantly 3-line spectrum within a few minutes after illumination in the presence of ferredoxin and NADP+. Analysis of the double integration of the first derivative EPR spectrum revealed no decrease in Biradical X concentration for more than 30 min of illumination. Our data suggest that Biradical X attaches to some soluble macromolecule(s) and that illumination of chloroplasts promotes such an attachment.


Specificity of substrate recognition by the EcoRI restriction endonuclease.

The substrate specificity of the EcoRI restriction endonuclease can be varied in vitro by changing the pH and the ionic environment of the reaction. Phosphodiester bond cleavage occurs at a DNA hexanucleotide sequence d(N-G-A-A-T-T-C-N)/d(N-C-T-T-A-A-G-N) when the ionic strength is high, 100 mM Tris-HCl, 50 mM NaCl, 5 mM MgCl2, and the pH is approximately 7.3. Lowering the ionic strength to 25 mM Tris-HCl, 2 mM MgCl2, and adjusting the pH to 8.5 reduces the recognition specificity of the EcoRI endonuclease to the tetranucleotide sequence, d(N-A-A-T-T-N)/d(N-T-T-A-A-N). The enzymatic activity responsible for this substrate recognition is referred to as EcoRI. Cleavage of pVH51 plasmid DNA under EcoRI conditions results in a number of partial digest fragments, some of which disappear slowly over a prolonged digestion period. This suggests that different recognition sites are cleaved at different rates. Comparison of DNA fragment patterns of modified and unmodified pVH51 DNA indicates that the canonical EcoRI sequence is the most rapidly cleaved site under EcoRI conditions. DNA modified in vivo by the EcoRI methylase is not cleaved by the EcoRI endonuclease under standard conditions, but is cleaved under EcoRI conditions at sites other than the standard EcoRI substrate.


Redox equilibria of liganded forms of methemoglobin.

We have examined the redox equilibria of azidomethemoglobin (low-spin) and fluoromethemoglobin (high-spin). We have derived a modified Hill equation which includes the tetramer--dimer equilibrium of the oxidized form, and also generalized the two-state model to incorporate ligand binding to the ferriheme. The pH dependence of the redox Hill's constant for fluoromethemoglobin is the same as that for methemoglobin, demonstrating that this dependence and the marked cooperativity achieved (n = 2.2) are not coupled to changes of the ferriheme spin state. The redox Hill's constant for azidomethemoglobin, however, is as large as the oxygenation Hill's constant (n approximately 2.7) and is also roughly pH independent.


Omega-aminoalkyl agaroses in the resolution of enzymes involved in regulation of glutamine metabolism.

Systematic examination of a homologous series of omega-aminoalkyl agaroses showed that the pentyl derivative (Seph-C5-NH2) was best suited for the retention and subsequent separation of several proteins involved in the regulation of glutamine metabolism in Escherichia coli, including: glutamine synthetase [EC 6.3.1.2; L-glutamate:ammonia ligase (ADP-forming)], ATP:glutamine synthetase adenylyltransferase (EC 2.7.7.42), the PII regulatory protein which regulates the adenylylation and deadenylylation activities of the adenylyltransferase, the UTP:PII protein uridylyltransferase, and the uridylyl removing enzyme which catalyzes the removal of uridylyl groups from uridylylated PII protein. Resolution of these proteins was achieved by gradually increasing the concentration of KCl in the eluant, which resulted in consecutive detachment of the proteins from the column. Proteins that co-elute from a DEAE-cellulose column can be resolved and further purified on epsilon-aminopentyl agarose, probably due to the fact that with the homologous series it is possible to adjust the contribution of hydrophobic interactions for optimal resolution.


Glutamine synthetase forms three- and seven-stranded helical cables.

When cobaltous ion is bound to glutamine synthetase [L-glutamate:ammonia ligase (ADP-forming), EC 6.3.1.2], the two-layered hexagonal molecules polymerize face-to-face, to form long strands. The strands then wind round each other to form three- and seven-stranded cables. The structures of these cables are not immediately evident from electron micrographs because of the confusing superposition of front and back portions of the cables. But optical diffraction and filtering by the procedure of Klug and DeRosier leads to interpretable images of the cables. Because a micrograph of the seven-stranded cable contains 24 views of the glutamine synthetase molecule, it is possible to reconstruct the three-dimensional electron density of a cable and its constituent molecules at a resolution of 30--50 A. This reconstruction confirms that the symmetry of a glutamine synthetase molecule is D6. It suggests that the single subunit is an oblate ellipsoid with its minor axis (about 48 A) roughly parallel to the 6-fold axis of the molecule and its major axis (about 63 A) perpendicular to the 6-fold axis of the molecule. The subunits of the two hexagonal layers of a molecule are eclipsed. Neighboring molecules along a strand also have their hexagonal faces together, but they are rotated about the strand axis by about 7 degrees with respect to one another, rather than being eclipsed. Six outer strands are coiled about a straight central strand, and each forms identical contacts with the central strand. Moreover, these contacts between central and outer strands are apparently similar to the contacts between neighboring outer strands.


31P magnetic resonance of tRNA.

We have observed well-resolved 31P resonances at 65 kG (109 MHz) in solutions of Escherichia coli tRNAGlu and yeast tRNAPhe. One resolved resonance, identified as the terminal phosphate, titrates with a pK = 6.35. Upon melting the yeast tRNAPhe in 0.1 M NaCl, without Mg++, the resolved peaks broaden and disappear in the vicinity of 35 degrees while the central cluster narrows drastically, shifts slightly, and loses its structure. Addition of Mg++ shifts one resolved peak and changes the shape of the cluster. The 31P lines are broader when observed at 65 kG than at 24 kG. The broadening is shown to come from chemical shift anisotropy which is estimated to be about 140 ppm.


Gene transfer to human cells: transducing phage lambda plac gene expression in GMI-gangliosidosis fibroblasts.

Genetic information from the bacterium Escherichia coli was transferred to human cells by means of the specialized transducing phage lambda plac carrying the bacterial z gene for the enzyme beta-galactosidase (geta-D-galactoside galactohydrolase, EC 3.2.1.23). As recipient cells, cultured skin fibroblasts from a patient with generalized gangliosidosis (GMI-gangliosidosis Type I) characterized by a severe deficiency of beta-galactosidase activity were used. The deficient human cells were incubated with the bacteriophage lambda plac or lambda plac DNA and beta-galactosidase activity was measured in order to detect gene transfer and acceptance of the prokaryotic information in the mammalian system for transcription and translation. The expression of the phage genome in the deficient fibroblasts could be demonstrated by detection of higher beta-galactosidase activity after incubation with phage lambda plac in three out of 19 experiments and in four out of 16 experiments after treatment with lambda plac DNA. Lambda plac DNA induced much higher enzyme activities than infective phage particles. Immunochemical and physicochemical assays could not distinguish the induced beta-galactosidase activity from that of the z-gene product of E. coli.


Bacteriophage T4 whiskers: a rudimentary environment-sensing device.

The 400 A filaments or "whiskers," which extend outward from the collar region of the phage, control retraction and extension of the tail fibers in response to certain environmental conditions. The tail fibers of normal phage retract in the absence of a required adsorption cofactor, at low pH, at low ionic strength, at low temperature, and at high concentrations of polyethylene glycol. The tail fibers of mutant whiskerless (wac) phage still retract under the first two conditions, but not the last three. Antibodies to whiskers neutralize T4, probably by fixing tail fibers in the retracted configuration. Phage with retracted tail fibers adsorb poorly to host bacterial cells, and their adsorption rate increases as the fibers become extended. These results suggest that one function of the whiskers is to retract the tail fibers and thereby prevent adsorption to host cells under certain conditions that might be unfavorable for production of phage progeny following infection.


Titration of sodium channels in canine gastric mucosa.

Net Na+ flux from mucosa to lumen, potential difference, and volume and plasma protein outputs were measured in vagally denervated, separated pouches of the dog's oxyntic or pyloric glandular mucosa when the pouches were irrigated with Na+-free solutions whose pH ranged from 1.5 to 12.2. The apparent permeability to Na+(P'Na) was calculated. P'Na is lowest when the mucosa is bathed with acid and increases 2- to 3-fold when the pH is raised to 10. In the range of pH 10.0--11.2 P'Na is greater by an order of magnitude, but volume output is small, and no plasma proteins are shed. When the pH is above 11.2 there is an abrupt increase in P'Na, and the mucosa sheds a large volume of fluid containing plasma proteins. The change effected by raising the pH to the range of 10.0--11.2 occurs within 10 sec, and it is reversible. The change effected by raising the pH above 11.2 also occurs within 10 sec, and it is partly reversible.


Influence of olfactory bulbectomy and the serotonergic system upon intermale aggression and maternal behavior in the mouse.

Biochemical parameters in the brains of olfactory bulbectomized male and female mice were studied in two experiments, followed by three experiments in which 5-HTP was injected into bulbectomized males and females to try to block abnormal behaviors. In Experiment 1 bulbectomized male and female mice had significantly less tryptophan hydroxylase in their brains than did sham controls. Neither 5-hydroxtryptophan decarboxylase nor tyrosine hydroxylase activity was affected. In Experiment 2 the rate of synthesis of 5-HT was significantly less in bulbectomized males and females. Since bulbectomy leads to increased pup killing by female mice, the objective of Experiments 3 and 4 was to see whether the injection of 5-HTP into bulbectomized females could block this behavior. The incidence of pup killing was not influenced, but in both studies the latency to kill was significantly prolonged. Olfactory bulbectomy eliminates aggressive behavior in male mice, and the purpose of Experiment 5 was to determine whether 5-HTP treatment could restore normal levels of aggression. No significant effect was found. The data suggest that a dual mechanism is needed to explain the behavioral abnomalities seen in the two sexes; the mechanism in the female appears to be serotonergic while that in the male is still unknown.


MSH affects regional perfusion of the brain.

With the single exception of the occipital cortex, the flow of blood to most regions of the brains of conscious, unrestrained rats was reduced within 10 min after intravenous administration of alphaMSH. Though these effects were transitory for most regions of the brain, perfusion of cerebellum, pons and medulla, hippocampus, and parietal cortex was still significantly low by 20 min. Assuming that flow changes reflect functional changes, these early responses to alphaMSH suggest an explanation for the effects of this hormone in which visual learning is improved.


Radioautographic localization of radioactivity in rat brain after intraventricular or intracarotid injection of 3H-L-prolyl-L-leucyl glycinamide.

Tritiated L-prolyl-L-leucyl-glycinamide was injected into the carotid artery or lateral ventricle of rats and the radioactivity localized by radioautography. After intracarotid administration, the radioactivity labeled the meninges, ependymal cells bordering the ventricles, and cells of the choroid plexus, as well as the median eminence and subfornical organ and thus may have reached the cerebrospinal fluid. After intraventricular injection, globus pallidus, indusium griseum, hippocampus, corpus callosum, and meninges. The results after intracarotid injection suggest that L-prolyl-L-leucyl-glycinamide may cross the blood brain barrier and the results after intraventricular injection suggest sites of localization which might be correlated with the previously reported effects of the tripeptide on the brain.


Early behavioral and catecholaminergic effects of 6-hydroxydopamine and guanethidine in the neonatal rat.

New born rats received 7 consecutive daily injections of 6-hydroxydopamine (6-OHDA) or guanethidine. Locomotor activity, measured at 3 day intervals, was differentially affected by these drugs, although neither drug elimination a characteristic pattern of ontogeny of locomotor activity. Differing neurochemical effects were also observed. 6-OHDA decreased tyrosine hydroxylase activity in cortex and cerebellum, increased it in the brainstem and had no effect on the hypothalamus. Guanethidine slightly elevated enzyme levels in all four brain regions, with the elevation in brainstem significant at 16 days of age. Regional brain changes in enzyme activity after 4 daily 6-OHDA injections beginning at 1, 5 or 9 days of age indicated that toxic effect of 6-OHDA upon catecholaminergic neurons was age dependent. These data are not consistent with a simple interpretation either in terms of maturational changes in blood brain barrier permeability to 6-OHDA or neuronal uptake of the drug. Further analyses of brainstem areas indicated that the increased brainstem enzyme activity after 6-OHDA was restricted to the pons.


Studies on accumulation of (14C)-mescaline in brain homogenates: effects of psychotropic and other agents.

Incubation of rat brain homogenates or 14,500 g pellet isolated from the homogenate with (14C)-mescaline was associated with accumulation of (14C)-mescaline in the pellet. 1.33 mumol/ml of chlorpromazine, trifluoperazine, fluphenazine, imipramine, desmethylimipramine, nortriptyline and amitriptyline inhibited the accumulation of mescaline. Lower concentrations (0.133-0.44 mumol/ml) of the psychotropic drugs were less effective. The tricyclic antidepressants were less potent than the tranquilizers. Although the trimethoxyphenylacetic acid (TMPA) levels of the pellet were also reduced by the psychotropic drugs, the TMPA:mescaline ratios were unchanged indicating that the drugs had no effect on the metabolism of mescaline. The inhibition of accumulation of mescaline by the high concentrations of tranquilizers may divert more of the hallucinogen to the receptor site. Thus, an explanation for the reported worsening of clinical syndrome of hallucinogenic poisoning by tranquilizers is provided.


Urinary purine levels in suicide.

A high-resolution liquid chromatographic system was utilized to analyze urine samples of twelve nonchemical suicide victims for the relative composition of ultraviolet-absorbing compounds. The analyses demonstrated a decrease in the output of uric acid, characteristic of severe depression, and an increase in the excretion of hypoxanthine. The excretion of 7-methylxanthine was found to be variable and xanthine was normal.


A comparison of the behaviour of human adult and foetal haemoglobins on oxidation.

The measurements of oxidation-reduction potentials at pH 7.0 and ionic strength of 0.1 revealed only a slight difference between human adult (HbA) and foetal haemoglobin (HbF) (161 and 145 mV), which  disappeared on increasing the ionic strength to 2.1. Kinetic data for the reactions with potassium ferricyanide and sodium nitrite of both haemoglobins in oxy- and carbonmonoxi-forms are presented at different excessive molar concentrations of oxidizing agents, in different environments at pH 7.0 and temperature ranging from 10--30 degrees C. The rate of HbF oxidation was considerably higher with both agents, despite vast differences in the reaction mechanisms.


On the significance of the increase in homovanillic acid (HVA) caused by antipsychotic drugs in corpus striatum and limbic forebrain.

The effect of various antipsychotic drugs on the blockade of dopaminergic receptors in striatum and limbic forebrain was examined by establishing dose-response curves for the increase in HVA and for the antagonism of d-amphetamine-induced rotation in rats with unilateral lesions of the substantia nigra. A good quantitative correlation was found between dopaminergic blockade in the striatum as reflected by the ED100 for striatal HVA increase and the ED50 for rotational antagonism and the occurrence of extrapyramidal side effects in man. The ED100 for the increase in HVA in the limbic forebrain showed the same rank order of potency as those in the striatum: Haloperidol greater than primozide greater than chlorpromazine greater than thioridazine greater than clozapine. The results thus demonstrate a very good correlation between the degree of dopaminergic blockade and the increase of extrapyramidal side effects in man, but suggest the possibility of a dissociation between dopaminergic blockade and antipsychotic activity.


Neurochemical evidence for tryptaminergic ascending and descending pathways in the spinal cord of the dog.

The brain and spinal cord of the chronic spinal dog contained higher levels of tryptamine than comparable regions of the intact dog. The most significant brain elevations were found in the cerebellum and mesencephalon. Further, tryptamine in the white matter of the spinal cord above the level of transection was higher than below. These findings have been interpreted as indicating that there are tryptaminergic pathways descending in the white matter of the spinal cord from the mesencephalon, cerebellum and rostral spinal cord. The level of tryptamine below the transection was not different from that found in the intact dog, suggesting that there are not only descending but ascending tryptaminergic pathways and that when the axons are transected. tryptamine accumulates proximal to the level of transection.


[Controlled research of the influence of Neoston on tracking performance, heart rate, sinus arrhythmia and on subjective rating of healthy subjects].

The influence of Neoston--a relatively new analgesic, antipyretic, and anti-inflammatory agent--on performance in different tracking tests, on heart rate, on sinus arrhythmia and on subjective rating was objectivated. 15 healthy male and female subjects, aged from 19 to 27 years, took part in the sessions lasting about 2 1/2 hrs each. Two times two pills Neoston or a placebo were taken orally 2 and 5 hrs before the tests, making a total of 2 g. Performance in tracking was poorer on the whole with Neoston than with placebo, but only up to a maximum of 5%. Except one measurement point out of 10 all differences between the tests with the active drug and placebo were not statistically significant at the level of 5%. Yet a relatively uniform trend suggests a certain but only a small damping effect of Neoston. When relating the data of the second and third session on the data of the first session of each day, damping effects could be made more obvious. Hereby the influence of Neoston on tracking performance could be demonstrated to exist also statistically significant but to be practically almost irrelevant. In physiological variables as well as in subjective rating only small differences between the drug and placebo condition were measured. When relating the results to comparable research on the effects of alcohol, tranquilizers and stimulants, it is concluded that with Neoston in the relatively high dosage as used here, no real detrimental effects on traffic safety are to be expected.


The actions of flunitrazepam (Rohypnol) on heart and respiratory rates and skin potential fluctuations during the sleep cycle in normal volunteers and neurotic patients with insomnia.

The actions of flunitrazepam (Rohypnol) were assessed on the sleep cycle, heart and respiratory rates and skin potential fluctuations of normal volunteers and neurotic patients with insomnia by means of all night recordings. The most conspicuous effect of flunitrazepam (2 mg p.o.) in the healthy subject's sleep cycle was an increase of the latency for the appearance of the first REM period. In the insomniacs the compounds was effective in inducing and maintaining sleep. Flunitrazepam diminished heart rates during the REM phases and significantly decreased the variability indices, this effect being more prominent in the normal subjects. Skin potential fluctuations during stages 2 and REM sleep were also decreased although tolerance developed rapidly in this connection.


Self-administration of CNS stimulants by dog.

Drug-naive dogs were trained to respond for intravenous infusions of either d-amphetamine, phenmetrazine, or methylphenidate until a stable response rate per 4-hr daily session was achieved. The magnitude of reinforcement (i.e., mg/kg/infusion) was then varied systematically across a wide range for each drug. An inverse relationship between unit dose and number of self-administered infusions per session was seen. Thus, total drug intake per session remained relatively constant and was independent of unit dose. Using a parallel line bioassay design, the relative potencies of d-amphetamine, phenmetrazine, and methylphenidate to maintain self-administration were estimated. By comparing the unit doses of d-amphetamine which yielded the same rate of self-administration it was found that 1 mg of phenmetrazine is equivalent to 0.1 mg of d-amphetamine. It was also determined that 1 mg of methylphenidate is equivalent to 0.75 mg of d-amphetamine. These data indicate the dog can be used to assess the reinforcing properties of psychomotor stimulants.


The composition and flow of parotid saliva during acute hyperkalaemia in sodium-deficient sheep.

Sheep were infused intravenously with 0-43 M-KCl at 2 ml/min for 2 hr while they were either sodium-replete or sodium-deficient after the unilateral loss of parotid saliva for 18 hr or 3 days. Salivary flow was depressed during potassium infusion and the flow rates observed at maximum hyperkalaemia were similar in all three states of sodium balance despite the large differences in flow rate before potassium infusion. The fall in salivary Na/K ratio during potassium administration was diphasic, the initial decline being slow and followed by a more rapid fall in the ratio. The duration of the initial period of slow decline in this ratio ranged from 75-105 min, 45-60 min, and about 15 min in the sodium-replete, mildly sodium-deficient and severely sodium-deficient states respectively. The decline in salivary flow during sodium depletion was associated with decreasing salivary bicarbonate concentration and increasing salivary phosphate and hydrogen ion concentrations with the concentration of chloride showing no consistent trend. During acute hyperkalaemia the chloride and phosphate concentrations were negatively correlated with salivary flow, the bicarbonate concentration was positively correlated with flow and the hydrogen ion concentration was unaltered. The sodium concentration of the saliva showed a statistically significant correlation with flow only when the sheep were severely sodium-deficient.


Characterization of soluble and microsomal adenosine 3',5'-monophosphate-dependent protein kinases from rabbit heart.

Cardiac microsomes contained an intrinsic adenosine 3',5'-monophosphate (cyclic AMP)-dependent protein kinase which stimulated phosphorylation of serine residue(s) of microsomal protein. The phosphorylated residues were associated with a microsomal protein component of 20,000 molecular weight as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Intrinsic phosphoprotein phosphatase activity of the microsomal membrane resulted in rapid dephosphorylation of these residues. Microsomes phosphorylated in the presence of cyclic AMP (10(-6) M) exhibited enhanced calcium uptake. We conclude that: 1) cardiac microsomes contain intrinsic cyclic AMP-dependent protein kinase(s) which phosphorylate a specific microsomal protein and phosphoprotein phosphatase(s) capable of dephosphorylating this protein, 2) phosphorylation of this protein enhances calcium uptake, 3) reversible phosphorylation of microsomal membrane may be an important mechanism for the regulation of calcium uptake of cardiac microsomes by cyclic AMP.


[The value of non-specific general therapy of shock caused by acute pancreatitis].

The shock in general, including that of acute pancreatitis, presents, according to our conception, as an energetic disease involving primarily the cell (by the intensive catabolic processes induced by the pancreatic lesion) and secondarily the most peripheral and mobile sector, that of the hemodynamic compartment. There is no etiological treatment of pancreatitis (the exceptions are very rare), and this is the reason for which we adopt a conservative attitude, and medical treatment, in the acute stage of the disease. The basic treatment of the shock of acute pancreatitis is considered to be the re-establishment of the circulatory volume with the aid of non-colloidal isotonic solutions that are given in large amounts (8-17 liters in a 24-hour period) under continuous perfusion. This technique is called hyperhydration or transrenal dialysis. Making use of this technique in the treatment of shock occurring in the course of acute pancreatitis the death-rate recorded was as low as 2,3% and the number of complications was very low.


Observations on the interaction of calcium and hydrogen ions on ATP hydrolysis by the contractile elements of cardiac muscle.

The ability of cardiac myosin, actomyosin, and myofibrils to hydrolyze ATP has been studied at varying hydrogen and calcium ion concentrations. The ATPase activity of dog cardiac myofibrils was measured over the pH range of 6.5-7.4, as the calcium ion concentration was varied from 0-1.5 X 10(-4) M. The ATPase of these myofibrils, and of rabbit cardiac myosin and actomyosin was also measured in the absence of ionic calcium over the pH range 6-9. The Km of MgATP of cardiac myofibrils was studied over the pH range 6.5-7.4. In the absence of calcium ions, myofibrillar, myosin, and actomyosin ATPase activities are maximal at pH 8.0. At any given calcium ion concentration, the myofibrillar ATPase is depressed by lowering pH. The results suggest that the influence of hydrogen ions on the ability of myofibrils to hydrolyze ATP is complex, and may not only be the result of a simple competition between hydrogen and calcium ions for binding sites on troponin.


The effect of temperature and mechanical work load on the intracellular pH and buffer capacity of cardiac muscle in rats.

The effect of temperature on hydrogen ions and buffer capacity in extracellular fluid differs from the effects in intracellular fluid. In our experiments cardiac hypertrophy was achieved by increasing the mechanical work load. It could be demonstrated that there is a certain correlation between buffering of hydrogen ions and mechanical activity of heart muscle.


Effect of H+ on force development of the heart muscle under acute respiratory failure by cyanide.

Force decay of slowly paced (12/min) isometric ventricular strips of frog heart at low temperature (+12 degrees C) was studied under standard cellular respiratory failure (3 mM NaCN). An exponential force decay obtained at pH0 6.0 was transformed to two-step decline by increasing the pH0. The rapid phase of the force decline was pH insensitive. The slope of the second slow phase was regulated by pH0 between 6.0 and 7.7 (force reduction to 50 percent was 7 min at pH 6.0 and more than 60 min at 7.7). This effect was partially blocked by citrate (1.5-3.0 mM). Data obtained are compared with pH values measured within the normal and ischemic myocardium and are discussed with respect to the role of proton accumulation and diffusion within the ischemic ventricular wall.


Calcium binding to cardiac sarcolemma.

Studies with a sarcolemma preparation from guinea pig hearts revealed two classes of Ca2+ binding sites: high affinity sites (Km' of 16 muM) and a 10-fold greater number of low affinity sites (Km' of 800 muM). Low affinity Ca2+ binding was inhibited by ruthenium red and verapamil, suggesting that these sites are located on the external side of the membrane. However, clear-cut competition between H+ and Ca2+ could not be demonstrated with isolated sarcolemma.


Labilization of lysosomes and mitochondria in situ by hypoxia and hypoxia-related factors.

Primary cultures of rat heart muscle and endothelioid cells were used to study the labilization of lysosomes and mitochondria by hypoxia, "hypoxia substitutes", and the in vivo-related factors of free fatty acid and pH. Subliminally-active levels tested were: hypoxia (1% O2/4 days), 5x10(-6)M sodium stearate: albumin in 6:1 ratio/30 min, KCN (1x10(-3)M/1 hr), 2 deoxy-glucose (3x10(-2)M/12 hr), acidosis (pH 6.9/30 min) and combinations. KCN plus 2-DG labilized the organelles in both cell types. Sensitivity to injury was in the order mitochondria greater than lysosomes and muscle cells greater than endothelioid cells.


Stimulus interaction in the responses of carotid body chemoreceptor single afferent fibers.

The characteristics of steady-state responses of single afferent fibers of carotid chemoreceptors to independent changes in arterial Po2, and Pco2 were investigated in cats. The arterial blood pressure was maintained within the normal limits (115-130 torr). Single chemoreceptor afferent fibers responded to changes both in arterial Po2 and Pco2. The relationship between the activity of chemoreceptors and changes in arterial Pco2 was linear at a constant arterial Po2. The two stimuli showed multiplicative interaction. The activity approached zero (threshold) as arterial Pco2 was decreased at a constant arterial Po2; a decrease in arterial Po2 decreased the arterial Pco2 threshold. These response characteristics of a single fiber suggest that the sensory receptor may be activated through a single mechanism by the two stimuli. The data fit into an idea that the mechanism may involve a conformational change in the membrane-bound polymeric chromophore group which reacts with O2 reversibly and shows a Bohr-shift.


Relationship between carotid chemoreceptor activity and ventilation in the cat.

The steady-state stimulus-response relations between arterial P02 and PCO2 and the mean activity of carotid chemoreceptors (single and multi-fiber) and ventilation were simultaneously recorded in 48 anesthetized cats. The carotid chemoreceptor activity varied linearly with the increase of arterial PCO2, below and above the normal value, at any given level of arterial P02. A decrease in arterial P02 increased the activity of the carotid chemoreceptors and increased its sensitivity to changes in arterial PCO2, showing multiplicative stimulus interaction. The authors also found that the response in ventilation during hypoxia to changes in arterial PCO2 below the normal value was smaller than that to changes above it, unlike the response of carotid chemoreceptors. This arterial PCO2 quasi-threshold for ventilation was, therefore, not due to a corresponding threshold for the activity of the carotid chemoreceptors but to a central mechanism. Above the central PaCO2 threshold, the ventilatory response to changes in PaCO2 and Pa02 resembled that of chemoreceptors but the ventilation dependent on hypoxia was greater than that could be directly accounted for by the activity of peripheral chemorecepors. A multiplicative interaction between the activity of peripheral chemoreceptors and central CO2 excitation appears to play a role in the regulation of ventilation.


Oxygen consumption and conservation during apnea in the anesthetized dog.

Apnea was initiated by clamping off the tracheal tube in 6 anesthetized dogs. Bradycardia, reduction in cardiac output and peripheral vasoconstriction developed gradually throughout the entire apneic period. O2 consumption during apnea was measured by monitoring the rate of O2  removal from the lung (VLO2), from the arterial blood (Va02), and from the venous blood (VV02). Total 02 consumption (VT02) was calculated by summing (VL02--Va02), VaQ2 and VV02-VL02, estimated by the product of arteriovenous O2 content difference and cardiac output, decreased continuously during apnea. At the end of 80 sec the rate of O2 removal from the lung was one-fourth of the pre-apneic rate, 5.29 +/- 0.51 ml-min-1kg-1. Oxygen disappearance form the blood was estimated by measuring arterial and venous O2 content at 20-sec intervals and by assuming a constant blood volume throughout the apneic period of 86 ml/kg, 25% of which is in the arterial tree and 75% of which is in the venous compartment. During the last 20 sec of an 80-sec apnea, VV02 represented 69% of VT02. The result indicated that VT02 during apnea was not significantly different from that of pre-apneic values. It is concluded from the present study that an oxygen conservation mechanism if existent, was not operative during an 80-sec apnea in the anesthetized dog.


Factors causing and reversing vasoconstriction in unventilated lung.

Vasoconstriction occuring a unventilated or hypoxic lung was studied in dogs and cats to elucidate mechanisms which both cause and reverse it. Lungs were perfused in vivo at constant pressure or constant blood flow; alternatively blood flow and pressure were measured with minimal operative interference. Stimulus-response curves of lung vessels to hypoxia showed a large response within the physiological range of P02 values. Vasoconstriction in unventilated lung caused by bronchial occlusion sometimes matched that caused by an equal degree of ventilation hypoxia but was sometimes greater. Responses to both stimuli varied widely between animals and in one animal at different times. This could be due to variable availability of a transmitter or variable presence of vasodilator substances. Both histamine and beta-adrenoreceptor stimulants caused pulmonary vasodilatation in unventilated lung. Histamine caused pulmonary vasoconstriction and vasodilatation in different circumstances which could be blocked respectively by H1 and H2 antihistamine drugs. Potent alpha- and beta-adrenoreceptor action on pulmonary vessels was demonstrated in both species. Alpha-adrenoreceptor blocking drugs caused dilatation and beta-adrenoreceptor blocking drugs caused vasoconstriction. The possible role of histamine and catecholamines in causing or reversing hypoxic vasoconstriction or in maintaining pulmonary vascular tone is discussed.


Oxygen uptake and blood respiratory properties of the caecilian Boulengerula taitanus.

In contrast to amphibians belonging to the orders Urodela and Anura, virtually no data exist on the respiratory physiology of the more primitive Apoda. This study concerns oxygen uptake and hemoglobin function in the caecilan Boulengerula taitanus, an apodan with fossorial habits. The oxygen uptake rate resembles that of other amphibians of similar size. The blood was high O2 capacity (14 vol%) and the erythrocytes are smaller, and the red cell count is greater than in other amphibians. The oxygen affinity of whole blood is high compared to other amphibians (P50 = 28 mm Hg at 25 degrees C and pH 7.6). The oxygen equilibrium curve is sigmoid (n = 1.79) and the Bohr factor is small (deltalog P50/deltapH = - 0.21). In 'stripped' hemoglobin solutions oxygen affinity increases strongly (P50 = 3.3 mm Hg at 25 degrees C and pH 7.6) and the temperature sensitivity is high (apparent deltaH=-19.4 kcal/mole), but the ATP and pH influences are too low to account for the difference in P50 compared to whole blood. The high oxygen capacity and oxygen affinity and the low Bohr factor may have adaptive significance to this fossorial amphibian.


Gastro-oesophageal acid reflux and sphincter pressure in normal human subjects.

Twelve-hour continuous recording of pH at the distal end of the oesophagus and manometric study of the basal gastro-oesophageal sphincter pressure were carried out in 26 normal human subjects. Eighteen of the 26 had 1-33 reflux episodes. The duration of each episode was shorter than 15 min in 16 of these 18 subjects. One single reflux episode lasting 15-30 min occurred in two, and one lasting 30-45 min was recorded in one. The total duration of low pH is expressed in percentages of the total time of recording and is dependent on the criteria used for low pH. On automatic analysis of the course of investigation, pH below 2.3 was found in five, pH below 3 in 17, and pH below 4 and 5, in 18 of the 26 subjects. Basal gastro-oesophageal sphincter pressure flutuated between 8 and 24 mmHg. The results of the study would suggest that in healthy, asymptomatic individuals the gastro-oesophageal barrier against reflux may be periodically incompetent. If contact between acid gastric contents and the oesophageal mucosa is a factor provoking the symptom heartburn, low oesophageal pH need not necessarily give rise to symptoms, i.e. the sensibility to low pH is either individual, or patients with symptoms have considerably more frequent and longer lasting episodes of reflux with low oesophageal pH than have normal subjects.


Elevation of serum gamma-glutamyl transpeptidase in end-stage chronic renal failure.

The serum gamma-glutamyl transpeptidase (GGT) was measured on 32 randomly selected patients about to commence or already on chronic haemodialysis. Raised values were found in 12 patients (37%). None of these patients had received drugs known to affect hepatic microsomes and all had normal liver function tests. The possible significance of this surprising finding is discussed.


Substance p: localization in the central nervous system and in some primary sensory neurons.

Antibodies to substance P with a high titer have been produced and used in immunohistochemical studies on the peripheral and central nervous system of the rat and the cat. Evidence was obtained for the localization of substance P in a certain population of primary sensory neurons, probably small nerve cells with unmyelinated processes. Substance P or a peptide similar to it was also observed in cell bodies in the medial habenula and in probable nerve terminals in many brain areas. The results give morphological support for a transmitter (or modulator) role of substance P in the nervous system.


Reproductive tract lesions in male mice exposed prenatally to diethylstilbestrol.

Sixty percent of the male offspring from pregnant mice treated with diethylstilbestrol during gestation were sterile. The affected animals had gonadal changes which included intra-abdominal or fibrotic testes, or both. Additionally, nodular masses in the ampullary region of the reproductive tract were observed in 6 of 24 animals; one of these appeared to be preneoplastic.


Lysinoalanine: presence in foods and food ingredients.

Lysinoalanine, N6-(DL-2-amino-2-carboxyethyl)-L-lysine, an unusual amino acid implicated as a renal toxic factor in rats, has been found in proteins of home-cooked and commercial foods and ingredients. Although it has been reported to occur in both edible and nonfood proteins only after alkali treatment, it has now been identified in food proteins that had not been subjected to alkali. Lysinoalanine is generated in a variety of proteins when heated under nonalkaline conditions.


Some factors affecting bone formation: a review.

Two separate methods exist at present to induce new bone formation. One utilises the implantation of specific materials, which may be of biological or non-biological origin. The other is based on the finding that bony tissue responds to very small electrical currents by stimulating osteogenesis at the negative electrode. This article discusses these methods in detail.


A modified reduced transport fluid for the preservation of Neisseria gonorrhoeae during transport.

Reduced transport fluid (RTF) was modified by altering its pH and by the addition of a yeast dialysate. This reduced transport yeast-containing fluid (RTYF) was shown to be superior to RTF in maintaining viability of Neisseria gonorrhoeae in cultures and in clinical material.


Benzodiazepines in psychiatry.

There are many difficulties in evaluating the efficacy of anxiolytic drugs, but their widespread and increasing clinical use confirms their effectiveness. The benzodiazepines, the most popular agents, offer certain advantages over the others. This article summarises the chemical properties and clinical effects of the benzodiazepines, and propose guidelines for the rational use of these agents in clinical practice.


Antimicrobial activity of human peritoneal fluid.

Cell free peritoneal fluids from 23 normal women had antimicrobial activity which was directed against gram-positive and gram-negative bacteria and also against yeasts. The activity was bacteriostatic or bactericidal and seemed to be due to the presence of a variety of factors which varied in their heat stability and dependence on complement. Lysozyme was present in the fluids but was not responsible for all the antimicrobial activity.


Orthotopic liver transplantation after preservation without perfusion for up to six hours: A controlled trial evaluating different preservation fluids in dogs and pigs.

The important extension of the ischemic period recently described with a simple hypothermic liver preservation method is attributed to the use of specific preservation fluids. However, there is no consensus about the optimal preservation fluid. In order to investigate the effect of the composition of the preservation fluid on the immediately postoperative transplant function and on subsequent long-term survival, orthotopic liver transplantations were performed in 13 dogs and 12 pigs. To reduce immunologic interference in postoperative transplant evaluation, donor and recipient pairs always were litter mates, the dogs being identical according to lymphocyte typing. The ischemic periods were 1, 3, and 6 hours. Four different preservation fluids were used with marked differences in ionic composition (extracellular vs. intracellular), pH, and osmolarity. Within each ischemic period group the sequence of experiments was randomized with respect to the different preservation fluids. Twenty-four animals survived the transplantation procedure. No differences were found between the preservation fluid groups. Postoperative function of all livers preserved for 6 hours was comparable to those with 1 hour ischemia. Three dogs and four pigs (six of seven with livers preserved for 3 to 6 hours) are still alive more than 1 year after transplantation. So consistently excellent liver function leading to long-term survival in 36 percent of cases can be obtained after liver transplantation with preservation up to 6 hours; for this result the composition of the preservation fluid is of minor importance.


Sympathectomy revisited: Dodo or phoenix?

Personal experience with temporary or permanent interruption of adrenergic impulses to brain, heart, kidney, pancreas, and the extemities is reviewed and certain concepts which were formulated long ago are re-emphasized. First, adrenergic blockade unmasks the cholinergic activity of the autonomic nervous system. This is apparent particularly when cardiac, renal, or pancreatic functions are studied under stress. Second, in the immediate treatment of cerebral, cardiac, or digital ischemia, the potentially reversible halo of edema around the irreversible necrosis is rapidly influenced by ganglionic blockade. And third, attention is called to the effect of adrenergic stimulation on sensory nerve endings which develop a higher threshold for pain when sympathetic fibers are interrupted. Although potent drugs inhibiting alpha and beta receptors or the release of catecholamines are widely in use, the obvious advantages of regional vs. systemic interruption of adrenergic impulses is pointed out. When the latter approach is pursued aggressively, the side effects are those of a total sympathectomy.


Purification and some properties of urokinase.

A method for efficient extraction of urokinase from human urine was established by using polyacrylonitrile synthetic fiber as an adsorbent. By a combination of this method and known methods for purification of proteins, such as gel filtration and ion-exchange chromatography, urokinase with a specific activity of 224,000 International Units per mg of protein was obtained. This sample showed homogeneity by ultracentrifugation, moving-boundary electrophoresis at pH 4.8 and 9.0 and polyacrylamide gel disc electrophoresis at pH 4.0, but was separated into five active fractions by isoelectric focusing and polyacrylamide gel disc electrophoresis at pH 9.4. This sample showed a single precipitin line in double radial immunodiffusion and immunoelectrophoresis using rabbit anti-urokinase serum. This precipitin line fused with that of the International Standard preparation of urokinase and its immunological identity was established. The molecular weight of this sample was 33,000, agreeing with that of the International Standard preparation. Its optimal pH as a plasminogen activator was approximately 8.8.


The effects of biguanides on thrombokinase, thrombin and trypsin.

A purified preparation of bovine thrombokinase (activated Factor X) loses the ability to hydrolyze TAME (p-toluenesulfonyl-L-arginine methyl ester) when it is incubated at 37 degrees in 0.25 M Tris. HCl buffer, pH 7.4 with lauroxypropyl biguanide, N1, N5-dimethyl, N1-lauroxypropyl biguanide, N1-p-chlorophenethyl, N5-phenethyl biguanide, or N1-methyl, N1-p-chlorobenzyl, N5-o,p-dichlorobenzyl biguanide. Activity is lost much more slowly when 0.15 M NaCl is also present. Lauroxypropyl biguanide is the most potent of the compounds tested, 0.22 mM causing thrombokinase to lose almost all of its activity in about 30 minutes at 37 degrees in pH 7.4 buffered saline. Topical bovine thrombin also loses activity when incubated with either of the lauroxypropyl biguanides but not with the diphenethyl or the dibenzyl compound. Instead, the latter biguanides accelerate thrombin's hydrolysis of TAME. The percent acceleration is not affected or only slightly decreased by the presence of 0.15 M NaCl or KCl, and it is also unaffected by incubating the enzyme with the compounds in buffered saline for 4 to 120 minutes. Purified bovine trypsin is stabilized by both lauroxypropyl and the diphenethyl biguanide when incubated at 37 degrees in pH 7.4 buffered saline for the 60 minute test period but neither compounds has any effect on its rate of hydrolysis of TAME. It is postulated that the enzymes first react rapidly and reversibly with all of the test biguanides and, depending upon the enzyme and the substrate, the rate of hydrolysis of the substrate is unaffected, accelerated or inhibited. The lauroxypropyl biguanides also undergo a second, slower reaction with both thrombokinase and thrombin that produces loss of enzymatic activity. The dibenzyl and diphenethyl biguanides also undergo this second slow reaction with thrombokinase but not with thrombin, and none of the biguanides undergo this second reaction with trypsin.


The influence of ascorbic acid on platelet structure and function.

To determine the effect on platelet behavior of transient exposure of platelets to ascorbic acid, studies of platelet function and ultrastructure were done before exposure to ascorbic acid at pH 6.5, during exposure to pH 6.5, and after restoration of pH to pre-acidification levels. The effect of ascorbic acid (A.A.) was compared to that of HCl and citric acid (C.A.). ADP- and collagen-induced aggregation of normal platelets were significantly impaired by both A.A. and C.A. but were less affected by HCl. The release of 14C-serotonin was significantly reduced by each agent. The ultrastructure of normal platelets brought to pH 6.5 by A.A. was normal. After neutralization, there was marked dilatation of the open channel system and loss of the disc shape. When platelets were brought to pH 6.5 by A.A., then neutralized, the aggregates which formed after stimulation by ADP or collagen were smaller than normal, the platelets were less closely approximated, and degranulation was less complete. The data show that exposure of platelets to ascorbic acid for short intervals impairs their function when measured after restoration of pH to levels compatible with maximal responses. Platelet survival studies using autologous platelets labelled with 51Cr in the presence or absence of ascorbic acid showed that the recovery of normal platelets was unaffected by ascorbic acid, whereas recovery of platelets from patients with idiopathic thrombocytopenic purpura, idiopathic thrombocythemia, and alcohol-related thrombocytopenia was markedly reduced. The injury resulting from the use of ascorbic acid in preparing platelets for studies of platelet survival in patients with disorders affecting platelets may impair the recovery of the cells, resulting in artifactual changes in the survival studies.


Hyperaggregability of platelets in thromboembolic disorders.

Platelet aggregability was measured using platelet rich plasma (PRP) collected from 197 clinical cases including 52 healthy volunteers. In 31 patients of acute stage of thrombosis (within 2 weeks from the onset), a significant enhancement of platelet aggregation measured 5 min after an addition of 3 and 10 muM ADP or 0.1 and 1 mug/ml of adrenaline to PRP (p less than 0.05, compared to the healthy group). Also a significant enhancement of secondary aggregation induced by adrenaline was observed (p less than 0.05). The enhancement was especially marked in the response induced by adrenaline. Such an enhancement was not observed in patients in the recovery stage of thrombosis, hypertension, angina pectoris and other miscellaneous diseases. There was no difference in the parameters related to the velocity of aggregation or intensity of primary aggregation between the diseased and the healthy group. In response induced by collagen (bovine achilles tendon, 0.3 and 1 mg/ml) any difference in the aggregation curve was not observed between the diseased and the healthy group. Such findings suggest a presence of an enhancement of ADP-release mechanism of platelets in acute thrombosis. Aslo a significance of adrenaline-induced platelet aggregation was proposed to detect platelet functions for analysis of mechanism of thromboembolic disorders.


Changes in plasma levels of LH, FSH and testosterone following the administration of synthetic luteinizing hormone-releasing hormone to cryptorchid patients.

The levels of LH, FSH and testosterone of three adult groups consisting of normal subjects, unilateral and bilateral cryptorcids were compared before and after LH-RH loading. It was found that both groups of cryptorchid had comparatively high plasma base line levels for both LH and FSH, particularly high in the bilateral group; and both groups responded to LH-RH loading. This indicates that their hypothalamo-hypophyseal systems were probably functioning normally. The plasma base line levels of testosterone were higher in unilateral cryptorchids than in the control group, and lowest in the bilateral cryptorchid group. But the reaction of testosterone levels to LH-RH loading was generally poor in both groups of cryptorchids, suggesting that, in cryptorchid cases, unilateral and bilateral, the capacity of the testicle to secrete testosterone is generally depressed, freeing central suppression. This probably accounts for the high values of plasma lh and FSH observed in such patients.


The depressor effect of dopamine on the electrical and mechanical activities of cat small intestine.

Effects of externally applied dopamine and other adrenergic stimulants on the electrical and mechanical activities of the cat small intestine were observed by using pressure electrodes. DOPA and dopamine reduced the spike and mechanical activities. The effects of dopamine were suppressed by treatment with phentolamine, phenoxybenzamine or propranolol. It seems that beta-response is predominant. Noradrenaline and adrenaline also blocked the spike generation and depressed the mechanical activity. Inhibitory actions caused by noradrenaline and adrenaline were blocked by adrenergic blockers. However, no significant effects of normetanephrine and metanephrine were detected. Dose-response curves for acetylcholine with and without dopamine, isoprenaline, phenylephrine and noradrenaline were obtained. The curves with adrenergic stimulants were shifted to higher concentrations of acetylcholine. Possible actions of dompanine were discussed in relation to adrenergic receptors of the cat small intestine. It is concluded that dopamine acts on alpha- and beta-receptors, and separate dopamine receptors could not be proposed by obtianed results.


An epidemiologic and serologic study of arboviruses in Lake Rudolf basin.

An epidemiologic and serologic study of arboviruses was done in 1972 in the basin of Lake Rudolf. The main object of this study was to demarcate the southern limit of the yellow fever epidemic which occurred from 1959 to 1962 in Southern Sudan and Ethiopia. Other purposes were to contribute to the inventory of arboviruses and their distribution in this region. The ethnic groups were studied: the Nyangatom and the Dassanetch in Ethiopia and the Turkana in northern Kenya. The results of tests on sera of the Nyangatom and the Dassanetch are practically identical: a high percentage of positive tests for group B. The Turkana on the other hand show a low percentage of positives. This is attributed to differences in the climatic characteristics of the two regions. The serological results suggest the presence of West Nile virus in the geographical areas inhabited by the three ethnic groups. The presence of Wesselsbron and probably Uganda S virus is suspected. Circulation of these viruses could be explained by the presence of Culex univittatus and other mosquitoes. As for yellow fever, the results suggest that the virus did not reach the areas studied, probably because of absence of efficient vectors.


Role of alpha-adrenergic receptor mechanism in closure of the internal urethral orifice during ejaculation.

The effects of autonomic drugs on closure of the internal urethral orifice during ejaculation were investigated in dogs. The closure of the internal urethral orifice was induced by the electric stimulation of the lateral fibers of the lower mesenteric plexus. The closing state of the orifice was measured with a latex balloon inserted into the orifice. The autonomic drugs were given into the aorta just above its bifurcation. From the results obtained in this study it was concluded that the closure of the internal urethral orifice during ejaculation is predominantly under the influence of the adrenergic nervous system, particularly through an alpha-adrenergic receptor mechanism.


Host defense mechanisms in the urinary tract.

In most episodes of urinary tract infection bacteria reach the bladder through the urethra and then may ascend to the kidneys through the ureters. Bacteria periodically enter the female urinary bladder from the urethra in small numbers. Whether infection ensues depends on the virulence and inoculum size of the microorganism and the adequacy of most defense mechanisms. Human urine is frequently inhibitory and sometimes bactericidal for the bacteria that cause urinary tract infection. Inhibition of bacterial growth coupled with voiding serves as a very effective antibacterial defense mechanism. In addition an intrinsic antibacterial defense mechanism has been demonstrated in the rat urinary bladder unrelated to urine flow. The medulla of the kidney is much more susceptible to infection than the cortex mainly related to its high osmolality. Certain abnormalities of the urinary tract interfere with host defense mechanisms and therefore predispose to urinary tract infection or make infection more difficut to eradicate once present. Some of these abnormalities are obstructive or neurological diseases of the urinary tract, vesicoureteral reflux, calculi, certain metabolic, hematologic, and vascular diseases, and pregnancy.


[Subastragalar dislocation of the foot].

An analysis of treatment in 22 patients with foot dislocation in the subastragalar joint is given. In fresh cases the dislocation could be easily reduced in a one-moment procedure under local anesthesia. As evidenced by the authors' findings in later terms arthrodesis of the subastragalar joint after operative correction of the foot deformity seems to be mostly effective.


[Acid-base values of porcine blood].

The main indices of acid-base balance of venous blood (v. auricularis extrema) were determined in 100 clinically disease-free pigs divided into categories with 20 animals each (piglets, pigs from 30 to 40 kg, pigs from 80 to 100 kg, sows, and boars). The Astrup method was employed for the determination of pH, pCO2, total CO2, BE, BB, AB in individuals, groups, and in the set as a whole. The Astrup PHM 71 and BMS 2 apparatuses were used. The results were summed up in a table and in graphs, including the Siggaard-Andersen curve nomogram. Statistical significance was calculated at p greater than 0.05. The average ABB values were determined in the set of 100 pigs; pH 7.306 +/- 0.013, pCO2 53.4 +/- 1.6 mmHg, total CO2 27.6 +/- 0.5, BE --1.0 +/- 0.4, BB 46.2 +/- 0.7, SB 23.5 +/- 0.4, AB 26.0 +/- 0.5 mEl-1.


[Effect of physical stress on the indices of acid-base homeostasis in pigs].

Investigated was the effect of physical stress--fixation with a cord at the collection of blood--on the values of the indexes of the acid-base homeostasis of the blood of pigs. It was found out that there existed two types of pigs reacting differently to physical stress. One is a labile type in which, after the stress, there occurs a rapid decrease of the pH of the blood, and the second is a stable type, in which the pH of the blood does not change. The decreasing of the pH in blood is more frequent in younger age categories of fattening pigs and gilts. Application of tranquillizers decreased, to a considerable extent, the occurrence of changes of the acid-base homeostasis of blood.


[Study of the enzyme activity of serum cystine aminopeptidase in man and animals in relation to the pH of the medium].

The authors studied the splitting dynamics of the synthetic chromogenic substrate (S-benzyl-L-cysteine-p-nitroanilide) specific of serum cystine aminopeptidase, depending on a wide range of pH (from 2.5 to 8.0) by means of an enzymatic serum system of pregnant women and selected animals (sheep, cows, sewer-rats), compared with non-pregnant controls. Examining the form of the enzymatic activity curves of the enzymatic system of women's and animal serum in dependence on pH, the authors revealed a characteristic bell-shaped course of the curve in the serum of pregnant women, as distinct from the sera of animals; the activity of cystine aminopeptidase in cows shows a two-peak course at pH from 3.5 to 4.0 and at pH from 6.5 to 7.0 while other animal species show irregularities with signs of the second peak. It follows from the results of the experiment that the main difference between pregnant and control animals is not the general increase of cystine aminopeptidase but a shift of the occurrence, or an increase of enzymatic activity at the given pH. The highest levels of cystine aminopeptidase were found in the blood sera of sewer-rats and lower in sheep and cows.


[Pathogenesis of aleutian mink disease. VII. Chronic hepatitis with bile duct proliferation].

Aleutian disease is a chronic persistent viral infection of mink characterized by hypergammaglobulinema, generalized plasmacytosis, sclerosing glomerulonephritis, polyarteritis, and plasma cell hepatitis with bile duct proliferation. The development of hepatic lesions was studied both light- and electron-microscopically in mink experimentally infected with Aleutian disease virus. Fifteen normal and 99 mink experimentally infected with Aleutian disease virus were used. Experimental mink were killed in intervals from 3 weeks to 23 months after infection, and liver sections were processed for both light- and electron-microscopic studies. Experimentally infected mink developed portal and intralobular lymphocytic and plasmacytic infiltrates in the liver 3 weeks after infection. Four to five weeks after infection there was evidence of early bile duct proliferation that began as an outgrowth of the portal bile ducts. Three to five months after infection a marked bile duct proliferation was present in some of the portal triads and adjacent liver lobules; but there was no tendency of these lesions to progress into biliary cirrhosis. Ultrastructural characteristics of proliferating bile duct cells were marked deformation, formation of multiple cell layers, reduction in the number of microvilli and desmosomes, and infiltration of the epithelial cells by lymphoid cells and plasmacytes. The hepatic lesions either develop by direct virus stimulation or by the deposition of virus-antibody complexes.


[Influence of gamma-rays on the general acidity and the water-soluble fatty acids of swine and cattle fats].

Studied were the changes in the total acidity and the amount of the water-soluble fatty acids in bovine and swine fats following the irradiation with gamma-rays. The treatment was effected by means of a 60Co source at 12--15 degrees C. The samples were kept at temperatures ranging from 2 to 4 degrees C, and from --18 to --20 degrees C in the course of 45 and 90 days, resp., being irradiated in the presence and absence of oxygen at rates of from 0.1 up to 2.0 Mrad. Results showed that gamma-treated at the rate of up to 2.00 Mrad produces no effect on the changes observed with the total acidity and the changes taking place during storage. The changes of the water-soluble fatty acids in the presence of oxygen, the type of fat, the temperature value, and the period of storage. The higher the irradiation rates used the greater the changes and shorter the time they need to take place. The presence of oxygen also proved of substantial importance for the changes in the amount of the watersoluble fatty acids. Bovine fats proved more sensitive to the changes referred to than swine fats.


[Mortality due to uremia resulting from chronic kidney diseases].

The investigation covers the necropsic material of the Pathological Anatomy Chair, Medical Academy-Sofia, with a total of 3519 necropsies for a period of 5 years (1968--1970). In that material, 285 cases with uremia were established, due to chronic renal diseases, which might be referred to 13 nozological entities. The highest number of cases are with chronic pyelonephritis (64,96 per cent). The chronic glomerulonephritis, though it ranks second, is considerably rarely met (9,47 per cent). Endemic nephropathy, according to the incidence, follows--4,21 per cent, nephropathy in diabetes mellitus--3,86 per cent, subacute glomerulonephritis--3,16 per cent, amyloidosis--2,81 per cent, hypertonic disease--2,81 per cent, malignant tumors of the kidneys--2,81 per cent cystic kidneys--2,10 per cent, lupus erythematosus--1,05 per cent, sclerodermia--0,70 per cent, myeloma disease--0,70 per cent and polyarteriitis nodosa--0,35 per cent. As to the chronic renal disease, most frequently met in the material discussed, the chronic pyelonephritis, the authors discuss the factors that played certain role in its development as well.


[Pulmonary function in papain induced emphysema in dogs (author's tranls)].

By intratracheal injection of the protease Papain to experimental animals parenchymal changes in the lung can be induced, that resemble human emphysema. Papain (dosage 26 to 112 mg, 1 to 4 injections) was given intratracheally to 8 bastard dogs, (weighing from 12.5 to 20 kg) during light general anesthesia. Pulmonary function was assessed in weekly intervals and related to morphologic changes in the lung. Static compliance of the lung and FRC measured during respiratory arrest were increased after papain, bronchial resistance, measured while artificially ventilated at constant pressure was also increased. Changes of static lung compliance and FRC were seen after the first administration of papain, but further increased with time of observation and after multiple doses of papain. Increase of resistance was not found before 5 weeks. At quiet breathing resistance was not increased at all. No significant changes were found of arterial pO2 and pCO2, pH, standard and actual bicarbonate, diffusion capacity for O2, tidal volume, minute ventilation and ventilatory rate. Morphological findings confirmed the changes described by others. Pulmonary function appears to be pathological at a time when morphology still seems to be normal. The question is discussed to what extent the model of experimental emphysema induced by proteolytic enzymes can contribute to the understanding of human pulmonary emphysema. Lung function in the course of experimental emphysema is compared with function in different clinical types of emphysema.


The p-hydroxylation of amphetamine and phentermine by rat liver microsomes.

1. The products of p-hydroxylation of amphetamine and phentermine by two different preparations of rat liver microsomes were identified and quantitatively determined. At low concentrations (muM) significant proportions of the substrates were metabolized to the p-hydroxy derivatives by an NADPH-dependent system. The enzyme system was inhibited by higher substrate concentrations (mM) and was not induced by either phenobarbital or 3-methylcholanthrene. 2. The properties of this in vitro system are consistent with reports on in vivo studies of this reaction.


Effect of mineral acids on iron bacteria.

The oxidative ability of Thiobacillus ferroxidans in the presence of different concentrations of H2SO4, HC1, HNO3, and their mixtures was investigated. Bacteriological oxidation of FeSO4 is expressed as a function of time and acid concentration. For each acid and for their mixtures lethal concentrations for T. ferroxidans were found experimentally. On the basis of the lethal concentration for each acid separately the lethal concentrations of their mixtures were computed and it was found that they are in good agreement with the experimental data.


[The effect of lumbar peridural anesthesia with catheter on the maternal and fetal acid-base status and the 1 minute apgar score (author's transl)].

Comparison of 650 deliveries with P.A. and of 928 deliveries without P.A. during the same period. PH from the umbilical artery and 1 minute Apgar score were studied in three groups of patients: 1.) All deliveries, 2.) Spontaneous vaginal deliveries without maternal or fetal risk, 3.) Operative vaginal deliveries. The only significant differences were found among the operative vaginal deliveries: The infants of the peridural group showed a higher incidence of pH-values above 7,2 than those of the non peridural group. Analysis of the maternal acid-base status showed less respiratory alcalosis and less metabolic acidosis in the peridural group. The neonates of this group showed a lower post partum metabolic acidosis than those in the non peridural group.


A rare type of low birthweight dwarfism: the Dubowitz syndrome.

Two patients with the Dubowitz syndrome are presented. This presumably recessive inherited syndrome was first defined by Grosse et al. (1971). So far 11 patients with this syndrome have been described. Major clinical findings are intrauterine and postnatal growth retardation, considerable microcephaly, mild mental retardation, hyperactivity, hyperextensibility of joints, eczema and a characteristic appearance of the face due to marked epicanthic folds, blepharophimosis, broadening of the bridge and tip of the nose and retrognathia. Minor anomalies as clinodactylyl of the firth digits, cutaneous syndactyly of toes, foot deformity, sacral dimple and cryptorchidism may be seen. The exclusion of the non genetic fetal alcohol syndrome presents serious diagnostic problems.


[Optimized determination and properties of NADPH-dependent glutathione reductase in serum. Studies on serum glutathione reductase, I. (author's transl)].

Reaction conditions were optimized for the determination of serum glutathione reductase, which has not yet been investigated systematically. Imidazole was found to be the most suitable buffer material; the highest glutathione reductase activity in serum was always obtained with imidazole/HCl buffer, which, in contrast to all other tested buffers, also resulted in the maximal enzyme activity without preincubation. In imidazole buffer, the pH-activity curve of serum glutathione reductase shows a broad optimum between pH 6.5 and 6.9. A GSSG concentration of 2 mmol/l and a NADPH concentration of 0.43 mmol/l gave maximal enzyme activity and a linear reaction over 10 min up to 20 U/l test solution. An investigation of serum glutathione reductase activity from 100 clinically healthy probands gave values between 20 and 50 U/l. In the optimized assay system the glutathione reductase in the serum reacts specifically with GSSG and NADPH.


Serum dopamine beta-hydroxylase: assay and enzyme properties.

A method for the estimation of dopamine beta-hydroxylase activity in human serum is described, based on a thin layer chromatographic separation of the substrate ([14C]tyramine) from the reaction product ([14C]octopamine). The basic properties of the human serum enzyme, investigated by this method are described.


Serum alpha-N-acetylglucosaminidase: determination, characterization, and corrective activity in Sanifilippo B fibroblasts.

Assays for the determination of serum alpha-N-acetylglucosaminidase (EC 3.2.1.50) activity are described employing p-nitrophenyl-N-acetyl-alpha-D-glucosaminide, phenyl-N-acetyl-alpha-D-glucosaminide, and UDP-N-acetylglucosamine as substrates. A log normal distribution of the serum enzyme activity was found. The determination of serum alpha-N-acetylglucosaminidase activity proved to be a valuable tool for the recognition of homozygous and heterozygous carriers of the Sanfilippo B gene.


The effect of heavy metal ions on the rate of decomposition of N-ethyl-N-nitrosourea and other carcinogenic N-nitrosamides.

The decomposition of ethylnitrosourea (ENU) in aqueous solution is enhanced by Cu2+ ions. Ni2+ shows a similar, but less pronounced effect. The decomposition rate of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), a compound known to be relatively stable in aqueous solution, is strongly enhanced by the addition of Cu2+ and to a smaller extent also by Ni2+ ions. On the other hand the stability of N-methyl-N-nitrosourethane is not influenced by heavy meatal ions. The influence of Cu2+ ions on the decomposition rate of ENU is similar to that of OH-anions, influencing the reaction kinetics on a molar basis. The increase in decomposition rate of ENU by copper ions is not seen in the presence of blood serum or other complexing agents. The results are discussed in relation to the known enhancement in toxicity and carcinogenicity of ENU by heavy metal salts in animal experiments.


[Gelelectrofocusing of protektin anti AHP from the albumin gland of Helix pomatia (author's transl)].

The protektin anti AHP from the albumine gland of Helix pomatia is a very interesting substance because of its ability to agglutinate erythrocytes of blood group A as well as group C streptococci. Purification is possible by reversible absorption on Sephadex G200. Isoelectric focusing in a sucrose density gradient is difficult, because the protein precipitates at the isoelectric point. The agglutinin, which is homogeneous in disk electrophoresis experiments (in an alkaline gel system as well as in an acidic one), shows around 9 bands in gelelectrofocusing. All components are able to agglutinate group C-streptococci. Complex formation between protein and ampholytes has been excluded by experiments in gels containing 7M urea. The region of the isoelectric points of the components is between pH 6 and pH 8. The inhomogeneity in gelelectrofocusing is caused probably by differences in the subunits of the protein molecule.