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Biomedical subjects

P Singer

Publications and source records attributed to P Singer.

At least 199 records · Page 11Linked to original sources
PubMed1982

Adipose cell size in patients with essential hypertension.

The fat cell volume from subcutaneous adipose tissue of the anterior abdominal wall has been evaluated in 10 male patients with essential hypertension and in 10 male normotensive control subjects of normal body weight as well as in 9 male obese hypertensives. In both groups with normal weight no significant differences could be confirmed whereas in hypertensives with overweight the adipose cell volume was significantly increased. Thus, no evidence of enlarged adipocytes as a primary defect in patients with high blood pressure could be obtained. The results are discussed in view of obesity, hyperlipoproteinaemia (HLP), increased lipolysis, impaired glucose tolerance, and high insulin response which frequently are associated with essential hypertension and usually favour the accumulation of triglycerides in hepatocytes and adipocytes.

Adipose Tissue↗
PubMed1982

Effect of linoleic acid-rich diet on blood pressure, lipids, catecholamines, and dopamine -beta-hydroxylase in spontaneously hypertensive rats.

Spontaneously hypertensive rats (SHR) and normotensive Wistar rats were fed a linoleic acid-rich (LAR) and -deficient (LAD) diet for 22 weeks, respectively. Although linoleic acid (LA) and arachidonic acid (AA) in serum and liver triglycerides markedly increased after a LAR diet, LA was significantly lower and AA was higher in SHR when compared to normotensive control rats. Thus, the percentage of both fatty acids remained different like in animals fed a commercial diet. On the contrary, in SHR and normotensive rats fed a LAD diet no differences in the LA and AA content could be found between the groups. In these rats, however, n-3 fatty acids (eicosapentaenoic and docosahexaenoic acids) in serum triglycerides were increased. Blood pressure, serum triglycerides and total cholesterol appeared unchanged, whereas HDL-cholesterol was increased after a LAR diet. Dopamine, adrenaline and noradrenaline content as well as dopamine-beta-hydroxylase activity were augmented in adrenal glands of SHR fed a LAR diet. In spite of distinct biochemical alterations the genetically determined hypertension in rats could not be influenced by a long-lasting diet containing a high amount of LA which has been proved to be effective on lowering blood pressure in other hypertensive rat models.

Animals↗
PubMed1981

[Fatty acid composition of triglycerides in inflammatory liver diseases in diabetics with and without hyperlipoproteinemia].

In 228 patients with diabetes mellitus (130 diabetics without and 98 diabetics with hyperlipoproteinaemia) percutaneous liver punctures after Menghini as well as biopsies of the subcutaneous fatty tissue were carried out. From the biopsy specimens and from serum the fatty acid pattern of triglycerides was estimated. In 87 patients with chronic aggressive hepatitis and 37 patients with fibrosis no differences in the fatty acid composition could be found. According to the present findings there was no evidence of alterations in the supply of individual fatty acids caused by chronic hepatitis per se. However, it is to be taken into consideration that simultaneous liver steatosis can provoke marked changes in the fatty acid pattern of liver triglycerides. The best reference seems to be the size of the fat droplet in the hepatocytes. Its rise is associated with an increase of palmitic and oleic acid, whereas the percentage of arachidonic and eicosapentaenoic acid is decreased. It must be clarified by further studies, whether this reveals a general pathophysiological phenomenon or is restricted to diabetic subjects.

Adult↗
PubMed1981

The natural history of retinopathy in insulin-dependent juvenile-onset diabetes.

We determined the cross-sectional natural history of retinopathy by prospective study of 461 insulin-dependent juvenile-onset diabetics. In so doing, we compared the sensitivity of ophthalmoscopy, photography, and fluorescein angiography in detecting retinopathy. Photography was far more reliable than ophthalmoscopy in detecting early retinopathy and equivalent to angiography. Retinopathy was not present at diagnosis of diabetes. After a lag period, the prevalence of retinopathy rose in sigmoidal fashion, reaching 50% at just over seven years duration, and asymptotically approaching 90% at 17--50 years. Proliferative retinopathy was first seen at 13 years duration, and its prevalence rose to 26% at 26--50 years. From the natural history we computed the dimensions of a proposed clinical trial to test the effect of tight metabolic control in prevention of retinopathy.

Diabetes Mellitus, Type 1↗
PubMed1981

Central nervous system toxicity of intraventricularly administered gentamicin in adult rabbits.

To determine whether daily intraventricular injection of gentamicin sulfate would cause neurologic or morphologic abnormalities of the central nervous system, adult male rabbits were given gentamicin sulfate, 2 mg/kg, intramuscularly twice a day plus saline, 0.2 ml (group 1), or gentamicin, 0.05 mg/kg (group 2), 0.25 mg/kg (group 3), or 0.5 mg/kg (group 4), given as the sulfate intraventricularly once a day. The majority of the animals in group 4 developed neurologic abnormalities which progressed to death in animals that were not euthanized; neuropathologic studies revealed chemical ventriculitis and meningitis that were associated with high levels of gentamicin in the cerebrospinal fluid and tissue of the central nervous system. Similar neurologic and morphologic changes were seen in most animals of group 3 but not in rabbits of groups 1 and 2. The ototoxicity and nephrotoxicity of gentamicin are well known; these data indicate that it may be toxic to the central nervous system as well.

Animals↗
PubMed1981

Meanings of combat and the development of posttraumatic stress disorder.

The authors use the concept of "meanings of combat" to explain combat veterans' different reactions to war experiences, particularly the development of a posttraumatic stress disorder after combat. The authors present four case reports to illustrate some of the different meanings of combat and the ways such meanings relate to stress disorder and soldiers' adaptation before, during, and after combat.

Adaptation, Psychological↗
PubMed1981

Posttetanic potentiation in a patient with myasthenia gravis.

We studied a patient with clinically typical myasthenia gravis (MG) and high serum titer of antibodies to acetylcholine receptor. Unlike the usual response in MG, there was an increment in the amplitude of the electrical response (308% of control) after 10 seconds of voluntary tetanus. Posttetanic facilitation is usually less than 200% in MG and over 200% in Eaton-Lambert syndrome. However, there have been several other cases of typical MG with increments over 200%. Facilitation of this magnitude has also been seen with curare administration in animals and man. However, in myasthenia, as opposed to curare poisoning, competitive blocking is not thought to exist.

Autoantibodies↗
PubMed1980

Decrease of eicosapentaenoic acid in fatty liver of diabetic subjects.

Simultaneous biopsies of liver and subcutaneous adipose tissue have been carried out in 228 patients with diabetes mellitus. In liver triglycerides a marked variability of the fatty acid pattern in relation to fatty degeneration of liver parenchyma has been confirmed. In adipose tissue fatty acid pattern was relatively constant. The most striking finding was a high content of eicosapentaenoic acid in normal liver and its decrease with the rise of lipid droplet size in the hepatocytes. No correlation with the quantity of liver fat or inflammatory liver diseases could be ascertained. When diabetes was associated with hyperlipoproteinemia (HLP) the percentage of eicosapentaenoic acid was significantly less. From the results the suggestion is obvious that a diminution of eicosapentaenoic acid in hepatic triglycerides is associated with lipid accumulation in the liver cells. A local mechanism, possibly the antilipolytic potency of prostaglandins, may be responsible for the creation of lipid droplets in liver cells of patients with metabolic disturbances. The alterations of eicosapentaenoic acid should be considered in view of recent data on the antiaggregatory effect of this fatty acid and its possibly preventive role for atherosclerosis.

Adipose Tissue↗
PubMed1980

High postheparin lipolytic activity as a possible cause of hypotriglyceridemia in spontaneously hypertensive rats.

In male spontaneously hypertensive rats (SHR) and normotensive Wistar rats at 4, 8 and 20 weeks of age the postheparin lipolytic activity (PHLA) has been estimated. PHLA was significantly higher in all SHR than in age- and weight-matched controls, although it decreased with advancing age in both groups. The data are discussed with regard to hyperinsulinemia and hypotriglyceridemia in SHR ascertained by a previous study. It is assumed that in young SHR catecholamine-induced lipolysis provokes impaired glucose tolerance and higher insulin response after glucose load. Insulin enhancement can stimulate PHLA via increased synthesis of lipoprotein lipase. The resulting augmented uptake of triglycerides by adipose tissue is suggested to be a beneficial (adaptive?) mechanism to compensate a primary increase of lipolysis. The well-known lower adipose cell size and body weight in SHR in comparison to age-related normotensive control rats might indicate that this mechanism is insufficient to balance the triglyceride supply in these animals.

Animals↗
PubMed1980

The fatty acid pattern of serum triglycerides and FFA in patients with essential hypertension of different stages, athletes, and normal subjects.

The fatty acid pattern of serum triglycerides and FFA in normal untrained subjects, normotensive athletes, patients with labile and stable essential hypertension as well as in hypertensives with overweight and mild hypertriglyceridemia has been evaluated by gas liquid chromatography. The most striking differences revealed the linoleic acid in triglycerides being increased in athletes and in patients with labile hypertension in comparison with normotensive untrained controls and patients with stable hypertension. On the basis of these data an enhanced need of polyunsaturated fatty acids corresponding to probands with high physical activity has been assumed in patients with an early stage of essential hypertension. The differences of arachidonic acid were not so distinct. The results can be relevant with regard to the pathogenetic role of prostaglandin precursors in the development and course of essential hypertension and atherosclerosis.

Adult↗