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Biomedical subjects

L Toth

Publications and source records attributed to L Toth.

At least 37 records · Page 2Linked to original sources
PubMed1987

Ischemia-induced neuronal cell death, calcium accumulation, and glial response in the hippocampus of the Mongolian gerbil and protection by propentofylline (HWA 285).

The localization and timing of cellular calcium loading and glial cell reaction in relation to selective death of hippocampal neurons was studied in Mongolian gerbils following transient forebrain ischemia. Two days after a 5-min period of ischemia, heavy calcium staining was histochemically demonstrated in circumscribed groups of nerve cells, located in the transition zone between the CA1 and CA3 areas. This preceded complete neuronal cell death that was quantitatively assessed by measuring the intensity of Nissl staining. After a 12-min period of ischemia, extensive calcium loading was observed in conjunction with severe neuronal damage throughout the CA1 region as well in the dorsal nuclei of the thalamus. The extent of calcium staining decreased with time and was not seen at stages later than 7 days. Already at 2 days after a 5-min period of ischemia, a strong increase of glial fibrillary acidic protein immunoreactivity was seen. This indicates a marked and early hypertrophy of astrocytes that was not accompanied by an obvious proliferation. Neither the astrocytic response nor the neuronal calcium accumulation were observed in gerbils pretreated with propentofylline, HWA 285 (10 mg/kg, i.p.) 15 min before bilateral carotid artery occlusion. Also, the decrease of Nissl staining in the CA1 area after 5 and 12 min of ischemia was considerably less pronounced and did not significantly differ from sham-operated controls.

Animals↗
PubMed1987

Effect of partial versus complete pancreatic denervation on pancreatic secretion.

The aim of this study is to compare the effect of various stimuli on pancreatic secretion in two groups of dogs, one undergoing interruption of the cholinergic and adrenergic branches to the pancreas (long arc reflexes), and the second group undergoing total denervation of the pancreas by its isolation from stomach and duodenum (short arc reflexes). Stimulation of pancreatic secretion was accomplished by (a) hormonal, by i.v. secretin and CCK/PZ and (b) reflex stimulation by intraduodenal administration of fat (Na oleate) or amino acids (Aminosyn). After a few weeks of collected data in stimulated controls, the dogs were divided into two groups: (A) Four dogs underwent proximal truncal vagotomy, celiac ganglionectomy, and stripping of the common hepatic and gastroduodenal arteries for 2-3 cm. (B) Four dogs underwent the same procedures, but in addition the pancreas was dissected away from its vascular and nervous attachments to the duodenal wall and pyloric region, as well as from its mesenteric and peritoneal attachments. All animals were then tested with secretin, Cholecystokinin/pancreozymin (CCK/PZ), intraduodenal fat, and intraduodenal amino acids. The data obtained indicate that secretion of pancreatic bicarbonate is dependent on intact local duodeno-pancreatic nervous reflexes. Fat and amino acids stimulate the secretion of bicarbonate only when the attachments of the pancreas to the stomach and duodenum are intact. Stimulation by secretion or CCK, being humoral-hormonal mediators, appears not to be affected by the local denervation.

Amino Acids↗
PubMed1986

The effect of hypovolemic shock on pancreatic secretion.

A vascular pathogenesis of pancreatitis has been postulated in diabetics, the aged, Ortner's Syndrome, and various low-flow states. This report studies canine pancreatic secretion in a preparation of hypovolemic shock produced by controlled hemorrhage maintained for varying durations. Pancreatic secretion was collected by cannulation of the main pancreatic duct in anesthetized dogs. Secretin was administered by continuous intravenous (i.v.) infusion of 4 U/kg/h. Four 15-min samples of pancreatic juice were collected. Then the dogs were bled by arterial line withdrawing 25-30% of total blood volume or until the mean blood pressure dropped to about 60 mmHg. Blood was collected in heparinized containers for reinfusion. Blood samples for amylase and 15-min samples of pancreatic juice for volume, bicarbonate, and enzymes were obtained during hypovolemia as well as during and following restoration of the blood volume. Hypovolemia induced significant decreases in pancreatic flow, bicarbonate and amylase secretion, parameters which increased after reinfusion but never returned to pre-shock levels. Increasing the period of hypovolemia increased the inhibition of pancreatic flow, increased blood amylase elevation, and resulted in visible pancreatic edema. We conclude that pancreatic secretion is diminished by hypovolemia, that this is initially reversible when hypovolemia is brief, but that the disturbance of function progresses to inflammatory pathology when hypovolemia is prolonged.

Amylases↗
PubMed1986

The effect of steroid administration on pancreatic secretion during and after hypovolemic shock.

In a previous report from this laboratory, 1 h of hypovolemia induced a significant decrease in pancreatic flow, bicarbonate and enzyme secretion. These parameters recover after restoration of blood volume, but never return to pre-shock levels. Furthermore, increasing the period of hypovolemia produced further decreases in pancreatic flow and bicarbonate secretion only. Enzyme secretion, however, rose significantly, probably due to leakage of protein through damaged cell membranes. Prolonged hypovolemia was also accompanied by visible edema. This model of secretory changes induced by fixed periods of hypovolemic shock is ideal to study the effect of steroids on secretion and to assess its possible cytoprotective properties against early induced ischemia pancreatic pathology. Pancreatic secretion was collected by cannulation of the main pancreatic duct in 12 anesthetized dogs. Secretin was administered by continuous intravenous (i.v.) infusion at 4 U/kg/h. Four 15-min samples of pancreatic juice were collected. Then the dogs were bled, withdrawing 25-30% of total blood volume or until the mean blood pressure dropped to about 60 mmHg. At this point, 30 mg/kg of methyl prednisolone were given in 50 cm3 of NaCl i.v. to six animals. Blood samples for amylase and 15-min collections of pancreatic juice for volume, bicarbonate and enzymes were obtained during hypovolemia, as well as during and following the restoration of blood volume. The responses of the two groups differed as follows: (1) Instead of the increase in protein enzyme secretion seen in the non-steroid group with increased duration of hypovolemia, steroid-treated dogs displayed a significant decrease in protein output.(ABSTRACT TRUNCATED AT 250 WORDS)

Amylases↗
PubMed1985

The pathogenesis of pancreatic pseudocysts--a canine experimental model.

In summary, an experimental model that mimics the pseudocyst formation in man was produced in dogs. The following conditions were met: encapsulated cyst containing pancreatic juice; an actively secreting pancreas with hyperamylasemia and pancreatitis; a ductal communication; and more pronounced effects with partial pancreatic ductal obstruction.

Amylases↗
PubMed1983

Use of chromatofocusing to distinguish estradiol receptor from ovarian-dependent and -independent rat mammary tumors.

Cytosol estradiol receptor from MTW9-D (ovarian dependent) and MTW9-MtT (ovarian independent) rat mammary tumors were fractionated by chromatofocusing, a procedure which separates proteins on an ion-exchange column as a function of isoelectric point. Receptor from MTW9-D usually fractionated as three peaks with mean pH at peak height of 7.5, 6.8, and 6.0. The intermediate peak at pH 6.8 was present in 90% of MTW9-D tumors examined but in only 20% of MTW9-MtT tumors. Treatment of cytosols with 20 mM sodium molybdate or 50 mM leupeptin did not change the chromatofocusing profiles. The pI 6.8 fraction of receptor bound quantitatively to DNA-cellulose after ammonium sulfate precipitation, while receptor in the other two peaks bound much less. The quantitative binding of a fraction of estradiol receptor characteristic of MTW9-D to DNA is consistent with the greater binding of unfractionated cytosol receptor from MTW9-D to DNA than the binding of receptor from MTW9-MtT. Sucrose gradient analysis of the pI 6.8 receptor showed a sedimentation coefficient slightly less than ovalbumin with a Stokes radius of 26 A as determined by agarose chromatography. The correlation of receptor binding to DNA with response to ovariectomy might make this form of receptor a potential marker of hormonal responsivity in mammary tumors.

Animals↗
PubMed1983

Pancreatic intraductal pressure: II. Effects of autonomic denervation.

The effects of autonomic denervation, local anaesthesia, and electrical stimulation on pancreatic intraductal pressure were studied in a group of dogs. Pressure studies were performed via a catheter placed in the distal pancreatic duct and by a transsphincteric route. Periampullary application of lidocain produced a decrease in the distal pancreatic duct pressure. Bilateral vagal section resulted in a significant pressure decrease while celiac ganglion plexus denervation produced additional pressure decreases. Electrical stimulation of the ampullary region resulted in a significant pressure increase. With transsphincteric pressure studies, bilateral vagotomy did not produce a significant pressure change, while celiac plexus denervation and pancreatic duct perfusion with lidocainin resulted in a moderate decrease in pressure. Electrical stimulation of the completely denervated perampullary region resulted in a significant pressure increase. These results suggest that the autonomic nervous system may affect the pancreatic ductal pressure, via its action on the sphincter mechanism of the main papilla, as well as on the ductal system. Local duodenopancreatic reflexes may play an additional role in controlling pancreatic duct pressure.

Animals↗
PubMed1982

Hypoalpha-hyperbeta-lipoproteinemia in a patient with coronary artery disease and occlusive peripheral arterial disease.

This study describes a variant of hypo-alpha-lipoproteinemia in a 57-year-old male patient. The total plasma cholesterol level was 258 mg/dl with 64% in esterified form. The concentration of triglycerides was 205 mg/dl. The lipoprotein electrophoretic pattern revealed the absence of alpha-lipoproteins, whereas the other lipoproteins showed an intermediate electrophoretic mobility. The concentration of HDL cholesterol (heparin: MgCl2 precipitation) was extremely low (3 mg/dl). The activity of lecithin; cholesterol acyltransferase (LCAT) and the postheparinlipolytic activity were within the normal range. Determination of apolipoproteins revealed a marked deficiency of both apoprotein A-I (17 mg/dl) and apolipoprotein A-II (11 mg/dl). The concentration of apolipoprotein-B was elevated (186 mg/dl). Unlike the clinical manifestations of Tangier disease, our patient did not show skin lesion, abnormal tonsils, hepatosplenomegaly, peripheral neurologic abnormalities or corneal deposits. Also in contrast to Tangier disease our patient had coronary artery disease with myocardial infarction accompanied with severe occlusive peripheral arterial disease.

Apoproteins↗
PubMed1982

[Age dependency of pulmonary artery pressure after myocardial infarction at rest and during exercise (author's transl)].

Functional disorders of the left ventricle at rest and under 6 minutes lasting bicycle ergometer exercise of 50 W were studied in 249 patients after myocardial infarction. By means of well defined circumstances, measurement of pulmonary artery diastolic pressure with floating catheter allows evaluation of left ventricular enddiastolic pressure. The upper borderline of this pressure is 20 mmHg which was reached in 45% of patients in the age group under 40, in 75% in those who are 60 and older. Independent to other exercise limiting factors, like angina, ischemic ECG-changes, augmented heart volume, congestive heart failure or critical extrasystoles, it could be shown that measurement of pulmonary artery pressure in these cases is the base for rational therapy like administration of digitalis, vasodilator drugs or beta-adrenergic blocking agents. Furthermore it can be predicted wether physical training could be usefull or dangerous.

Adult↗
PubMed1978

[Significance of pulmonary artery diastolic pressure after myocardial infarction for physical training (author's transl)].

Functional disorders of the left ventricle after myocardial infarction at rest and with exercise can be evaluated with right heart floating catheter by measuring pulmonary artery diastolic pressure. 45% of 200 patients with myocardial infarctions did not tolerate bicycle exercise test with a work load of 50 Watt during 6 minutes. A routine digitalisation of these patients without strict indication did not improve the results. The upper borderline to admit a physical training program is a pulmonary artery diastolic pressure of 20 mm Hg; this should be realised otherwise additional complications have to be expected in long term follow up. The effects of digitalis should be controlled with floating catheter observations in these patients too. There are some indications, that it is possible with the same technique to evaluate hemodynamic responses on psychological strain. Measurements of pulmonary artery diastolic pressure after myocardial infarction open a wide field for individual therapy from drugs to physical training and even to behaviour therapy for stressfull situations.

Adult↗