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Biomedical subjects

J Simon

Publications and source records attributed to J Simon.

At least 487 records · Page 27Linked to original sources
PubMed1985

Effects of V.M.H. lesions on plasma insulin in the goose.

The effects of bilateral electrolytic lesions of the ventromedial hypothalamus (V.M.H.) were examined in male geese. In addition to the known effects (hyperphagia, obesity and liver steatosis), V.M.H. lesions slightly increased plasma insulin level in the fasting and the fed state and largely enhanced insulin levels observed during an oral glucose and amino acid load. Therefore, V.M.H. lesions potentiate insulin release which may in turn participate in the development of hyperphagia and fattening in the goose as in mammals.

Animals↗
PubMed1985

Time-resolved photoelectric and absorption signals from oriented purple membranes immobilized in gel.

Kinetics of photoelectric and absorption response signals were measured on samples containing oriented purple membranes immobilized in polyacrylamide gel. The orientation and aggregation states of purple membranes remain constant independently of pH and ionic strength in such samples and the gel does not influence the proton pump. The 'gel method' described in this study enables direct investigation of proton pump of bacteriorhodopsin and a simultaneous measurement of absorption signals within a wide range of parameters of the solution surrounding purple membranes and offers possibilities for study of other types of membranes as well.

Acrylic Resins↗
PubMed1985

Unusual sites of schwannoma in the head and neck.

Two cases of schwannoma originating in unusual sites in the head and neck are reported. To the best of our knowledge ours is the first case of schwannoma in the nasopharyngeal area to be described. Schwannomas in the parotid area must be kept in mind in the differential diagnosis of parotid tumours. The pertinent literature is reviewed.

Child↗
PubMed1985

Fat and lean chickens: prefattening period and in vivo sensitivity to insulin, atropine, and propranolol.

Fat (FL) or lean (LL) chickens have been obtained by divergent selection. In previous studies, FL chickens were consistently hypoglycemic (slightly) and had high plasma levels of insulin in response to glucose or refeeding from 5 to 8 wk of age. In these, at 12-13 days of age before any difference in fattening can be demonstrated, FL chickens exhibit a better glucose tolerance pattern and enhanced glucose-induced insulin levels but normal insulin levels during refeeding. Plasma levels of alpha-NH2 nonprotein nitrogen, uric acid, free fatty acids, and potassium were neither consistent nor significantly different between lines. Atropine, at high dose, blocked the absorption of glucose and at low dose had no major effect on glucose-induced insulin release in either line. At 8 wk, sensitivity to and disappearance of exogenous insulin were normal in FL birds. Propranolol slightly decreased plasma glucose and inhibited the hypokalemic effect of exogenous insulin to the same extent in both lines. Cerebrospinal fluid glucose level and liver glycogen content were similar in both lines in the fasting or the fed state, but liver glycogen was restored faster after refeeding in the FL, at least in older birds.

Adipose Tissue↗
PubMed1985

Species susceptibility to the pulmonary toxicity of 3-furyl isoamyl ketone (perilla ketone): in vivo support for involvement of the lung monooxygenase system.

To explore a possible relationship between metabolism and lethality, the acute toxicity of naturally occurring perilla ketone (PK), 1-(3-furyl)-4-methyl-pentan-1-one, was examined in the uninduced mouse, hamster, rabbit, dog and pig. The LD50 (+/- SE), determined using intraperitoneal (ip) injection, for the mouse and hamster were low at 5.0 +/- .3 and 13.7 +/- .9 mg/kg, respectively. The rabbit died from an ip dosage of near 14 mg/kg and estimated ip LD50 dosages were quite high for the dog and pig, being 106 +/- 25 mg/kg and over 158 mg/kg, respectively. Dogs and the pig that died from ip injections of PK displayed varying degrees of midzonal and centrilobular liver damage and dogs also had elevated serum alkaline phosphatase and glutamic-pyruvic transaminase activities. In contrast, rodents and rabbits display only pulmonary toxicity from this agent. Cytochromes P-450 and b5 concentrations and NADPH-cytochrome c reductase activity were determined for the lung, liver and kidney of mice, hamsters, rabbits, dogs, swine, sheep and cattle. High correlation between lethality and enzyme concentration further supports the hypothesis that enzymatic bioactivation of PK is required for toxicity in all species.

Alanine Transaminase↗
PubMed1985

Perinatal piglets under sublethal concentrations of atmospheric carbon monoxide.

Perinatal exposure to atmospheric carbon monoxide at sublethal concentrations affected neonatal piglets negatively. Low total hemoglobin concentration and oxyhemoglobin saturation ratio were present at birth in piglets farrowed by gilts that had been exposed to carbon monoxide at 250 ppm from gestation d 109 on, but stillbirth rate was only 4.8%. Carboxyhemoglobin saturation ratio increased from .0 to 19.8 and 22.4% as carbon monoxide concentration rose from background (less than 5 ppm) to 200 and 250 ppm. Carbon monoxide affected neonatal piglets' behavior. Piglets exposed to atmospheric carbon monoxide at 250 ppm perinatally took longer to nurse for the first time than did counterparts under background or 200-ppm concentrations. Those under carbon monoxide at 250 ppm had compromised performance in behavior tests that measured a piglet's ability to orient itself in, maneuver in and investigate its environment, respectively.

Animals↗
PubMed1985

Laying performances, egg composition, and glucose tolerance of genetically lean or fat meat-type breeders.

Genetically fat and lean breeders were compared for laying performance and glucose tolerance. Laying females were fed ad libitum or restricted (85% ad libitum). Ad libitum-fed fat breeder hens (FL) were lighter and produced lighter eggs than lean hens (LL). However, the yolk percentage of the egg and yolk output were higher in FL. Differences in the glucose-insulin balance were consistently observed between lines in females at 203 and 326 days and in males at 203 days of age. The FL birds displayed lower plasma glucose and higher plasma insulin concentrations for a given plasma glucose level. Feed restriction reduced egg output, yolk output, yolk lipids, and plasma insulin levels during glucose tolerance in females at 326 days of age. Therefore, the glucose-insulin imbalance previously described in young FL birds persists in adults. The enhanced propensity of the FL to synthesize and deposit lipids also affects vitellogenesis. Insulin is also implicated in vitellogenesis.

Animal Feed↗
PubMed1985

Inhibition of histalog-stimulated gastric secretion by 40 749 RP, a new long-acting gastric antisecretory agent.

40 749 RP, an N-methyl-2-(2-pyridyl)-2,3,4,5-tetrahydro-2-thiophene carbothioamide derivative, is already known as a potent gastric antisecretory agent in animals and in man. In order to determine its duration of action, its activity was investigated on Histalog-stimulated gastric acid secretion in 6 healthy volunteers. The efficacy of a 2 mg/kg dose, compared with that of placebo, was potent, and remained the same when the drug was ingested 6 h before stimulation instead of 1 h. The duration of action of 40 749 RP is therefore longer than 6 h.

Adult↗
PubMed1985

Incidence and risk of coronary heart disease in an industrial population. A five-year prospective study.

In a large machinery factory a cohort of 3754 men aged between 40 and 50 years have been studied for 5 years. Total and coronary mortality rates have been determined and also the incidence of certain non-fatal states which required hospitalization due to various types of coronary heart disease (CHD), hypertension, brain apoplexy, diabetes mellitus and malignancies. Among the subjects exposed to CHD risk factors (RF), i.e. among smokers, hypertensive and hypercholesterolemic subjects, and among those who had a positive coronary family history and a positive cardiovascular (chest pain) questionnaire, both total and coronary mortality rates were several fold higher and they increased almost exponentially with increasing numbers of RF. Among the RF it was the cardiovascular (chest pain) questionnaire which had the highest prognostic value. Workmen manifested a higher total and coronary mortality than did the employees in the technico-economical professions (TEP). The highest mortality rate was found among the workmen employed in heavy manual occupation. In contrast the lowest total coronary mortality rate was observed in the TEP having little responsibility in their vocation and also among qualified workmen and specialized technical and scientifical workers.

Actuarial Analysis↗
PubMed1984

Pulmonary varices, benign congenital anomalies simulating perihilar masses of various etiologies.

Pulmonary varices are rare and relatively benign congenital malformations. These localized aneurysmatic dilatations of pulmonary veins drain normally to the left atrium. Their radiological appearance may simulate perihilar masses of neoplastic or granulomatous origin and pulmonary arteriovenous fistulae, thus, potentially leading to diagnostic pitfalls. The diagnosis is made during the venous phase of pulmonary angiography which is always necessary in order to avoid unnecessary surgical procedures. An illustrative case and discussion of the subject is presented herein.

Arteriovenous Fistula↗
PubMed1984

Ascending spinal axons that signal the position of the hindlimbs under static conditions: location and receptor input.

Psychophysical experiments have shown that signals from slowly adapting subcutaneous receptors are used to sense limb position under static conditions (i.e., when the joints are stationary). The ascending collaterals of the slowly adapting primary sensory neurons supplying the deep tissues of the hindlimb do not project to the brain via the fasciculus gracilis. In experiments on cats, we have found a population of axons in the lateral fasciculus that signal the position of the ipsilateral hindlimb with a slowly adapting discharge. In the lower thoracic cord these fibers lie between the spinocervical tract and the ventral roots. Although plentiful in the lower thoracic cord, they are sparse or absent below L3. In addition, a few position signaling axons with crossed input were found in the ventral part of the lateral white matter and in the ventral columns. Since the clinical evidence suggests that the spinal pathway for position sense is uncrossed, we propose that information used for conscious judgments of limb position when the joints are stationary initially ascends via the dorsal columns and then relays to the lateral fasciculus on the same side. These slowly adapting signals also may be used to judge limb position when the joints are moving. To determine whether this slowly adapting discharge originates from muscle or joint receptors, the tendons crossing the ankle joint were exposed but left in continuity and then pulled on while the joint was stationary. In this way individual lateral fascicular axons that signaled ankle flexion, extension, abduction or adduction could be shown to receive a strong excitatory input from muscle receptors. After the muscle tendons crossing the ankle joint were cut, tract fibers signaling ankle flexion, extension, abduction or adduction could no longer be found in this portion of the spinal white matter. Axons signaling clockwise or counterclockwise twist of the ankle were reduced in number but a few were still present. These results suggest that muscle receptors provide the predominant signal used to sense ankle flexion, extension, abduction and adduction and that receptors in articular tissues may signal ankle twist.

Afferent Pathways↗
PubMed1984

Signaling of ankle joint position by receptors in different muscles.

Plots were made of multiunit activity versus ankle joint position for receptors in each of the 12 muscles crossing the cat ankle joint, except peroneus tertius, by recording from populations of afferent fibers in muscle nerves. The discharge was measured 15 or 30 sec after terminating the movements that altered the position of the joint. These recordings were dominated by large-spike activity that would be expected to originate mainly from primary spindle endings. Seven of the 12 muscles also cross other joints. Their responses at a given ankle joint position were so altered by changes in the position of the knee or toe joints that they could not reliably signal the position of the ankle joint. As judged from multiunit recording, receptors in each of the five muscles specific to the ankle joint were influenced by more than one axis of ankle joint displacement. Single-unit recording from dorsal root filaments was used to determine whether primary or secondary spindle receptors in soleus and tibialis anterior could selectively signal one axis of ankle joint rotation. Individual soleus receptors were tested both on the flexion-extension axis and with a combined adduction-eversion movement. For 38 of the 70 soleus receptors examined (54%), firm adduction-eversion produced a level of activity greater than that caused by 10 degrees of flexion, and for 77% the level of activity was greater than that caused by 5 degrees of flexion. For 168 of the 184 tibialis anterior receptors studied (91%), firm abduction-inversion produced a level of activity greater than that caused by 10 degrees of extension. Thus few receptors were found that responded exclusively to one axis of rotation. One way in which the position of the ankle joint could be specified in the face of multiaxial receptor activity is by examining the receptor discharge from more than one muscle. A suggestion for how the nervous system might do this is given in the discussion.

Afferent Pathways↗
PubMed1984

The combined effects of dietary protein and fat on 7,12-dimethylbenz(a)anthracene-induced breast cancer in rats.

A 3 X 3 factorial experiment was conducted to examine how protein content (8, 16, 32% of kilocalories from casein) and fat content (12, 24, 48% of kilocalories from corn oil) interact to influence 7,12-dimethylbenz(a)anthracene (DMBA)-induced breast carcinogenesis in rats. Forty weanling Sprague-Dawley rats were assigned to each of 9 diets fed ad libitum. After 4 weeks each rat received DMBA (20 mg/kg) via gastric intubation. No substantial statistical interactions of protein and fat were observed on tumor incidence. Increasing dietary corn oil increased the percentage of rats with palpable tumors. Rats fed diets containing 12, 24 and 48% of kilocalories from corn oil showed 35, 49 and 70% tumor prevalence at necropsy, and the total number of tumors per fat level was 65, 81 and 182, respectively. Each doubling of dietary fat concentration approximately doubled the odds of a rat developing a tumor. Multiple tumors were more common with the highest corn oil intake. The odds of finding a second tumor in rats with one tumor increased by a factor of 7.5 when fat kilocalories were increased from 24 to 48% compared to a decrease of one-third when fat kilocalories were increased from 12 to 24%. Dietary corn oil significantly increased the prevalence of adenocarcinomas and adenomas but not fibroadenomas. Dietary protein did not significantly affect tumor prevalence. However, tumors palpated in rats fed 16% of kilocalories as protein regressed more frequently than in rats fed low or high protein diets. Multiple logistic-regression results indicate that, in addition to the response to dietary corn oil, tumorigenesis was increased in rats with greater ad libitum food consumption. This conclusion is supported by reanalysis that used direct rate adjustment and average partial association tests.

9,10-Dimethyl-1,2-benzanthracene↗