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Biomedical subjects

I Farkas

Publications and source records attributed to I Farkas.

At least 55 records · Page 3Linked to original sources
PubMed1988

Activation/dephosphorylation of rabbit muscle glycogen synthase by the catalytic subunits of protein phosphatase-1 and 2A.

Glycogen synthase a was purified from rabbit skeletal muscle by a procedure involving heparin-Sepharose chromatography. Glycogen synthase a was phosphorylated by the catalytic subunit of cAMP-dependent protein kinase to give synthase b1. Dephosphorylation and activation of synthase b1 was investigated using the catalytic subunits of protein phosphatase-1 and 2A. The dephosphorylation and activation of synthase b1 was biphasic with a larger rate constant for the initial phase. Analysis of tryptic phosphopeptides of glycogen synthase during the course of dephosphorylation revealed a faster initial phosphate release from site-2 by both phosphatases comparing to sites-1a and 1b. Ligand effects on synthase phosphatase reactions were also studied. Spermine was found to inhibit protein phosphatase-1 activity and to stimulate type-2A phosphatase using synthase b1 as substrate.

Animals↗
PubMed1987

Insoluble glycogen and its interaction with phosphorylase. A novel method for the purification of liver phosphorylase A.

Purified liver glycogen dissolved in Tris-HCl buffer (pH 6.8) was converted into an insoluble polymer by incubation with phosphorylase and glucose 1-phosphate. Elongation of the outer chains of glycogen did not alter the average molecular weight significantly as judged by sedimentation velocity measurements, but the spectrophotometric analysis of glycogen-iodine complexes showed marked differences. Insoluble glycogen could bind rabbit skeletal muscle and liver phosphorylases. The association of insoluble glycogen with phosphorylase could be treated as a distribution equilibrium between glycogen-bound and unbound phosphorylase. Based on the formation of an insoluble glycogen protein complex sedimentable even by low-speed centrifugation, a novel method has been developed for the purification of liver phosphorylase a in a homogeneous form.

Animals↗
PubMed1986

Hormonal regulation of phosphorylase phosphatase activity in rat liver.

The effect of glucagon and insulin on rat liver phosphorylase phosphatase activity in vivo was investigated. The activity of phosphatase was found to decrease following the administration of glucagon and increase with insulin in a reversible manner. No change was detected in the activity of heat-stable phosphatase inhibitors in the hormone-treated samples. Liver protein kinases (regulatory subunit of cAMP-dependent protein kinase and/or Ca2+-dependent phosphorylase kinase) are suggested to regulate the activity of hepatic phosphorylase phosphatase (type 1 and 2A).

Animals↗
PubMed1986

Relationships between serum FSH level and the size of testis in azoospermic patients.

Sixty-eight out of 700 patients proved to be azoospermic at our Andrology Clinic between 1981 and 1983. According to the serum FSH level and testis size, three main diagnostic groups were established: 1. patients with occlusion but testis size and FSH level normal; 2. patients with smaller testis size and increased FSH level and primary spermatogenetic disorder; 3. non-palpable testis and increased serum FSH level referring also to testicular disorder. No correlations were found between serum LH and testosterone levels and testicular volume.

Follicle Stimulating Hormone↗
PubMed1985

Effect of fructose 1-phosphate on the activation of liver glycogen synthase.

The activation (dephosphorylation) of glycogen synthase and the inactivation (dephosphorylation) of phosphorylase in rat liver extracts on the administration of fructose were examined. The lag in the conversion of synthase b into a was cancelled, owing to the accumulation of fructose 1-phosphate. A decrease in the rate of dephosphorylation of phosphorylase a was also observed. The latency re-appeared in gel-filtered liver extracts. Similar latency was demonstrated in extracts from glucagon-treated rats. Addition of fructose 1-phosphate to the extract was able to abolish the latency, and the activation of glycogen synthase and the inactivation of phosphorylase occurred simultaneously. Fructose 1-phosphate increased the activity of glycogen synthase b measured in the presence of 0.2-0.4 mM-glucose 6-phosphate. According to kinetic investigations, fructose 1-phosphate increased the affinity of synthase b for its substrate, UDP-glucose. The accumulation of fructose 1-phosphate resulted in glycogen synthesis in the liver by inducing the enzymic activity of glycogen synthase b in the presence of glucose 6-phosphate in vivo and by promoting the activation of glycogen synthase.

Animals↗
PubMed1983

[Gonadotropin treatment in corpus luteum insufficiency-induced functional sterility].

The authors report on gonadotropin treatment of 91 women who were infertile due to luteal dysfunction. As an effect of treatment there was an improvement of the corpus luteum function in 77 patients (84.6%), and 30 of them (33.0%) became pregnant. Application of HCG is recommended in cases if clomiphene treatment proved ineffective previously. Application of FSH and HCG is recommended at low level of estrogen.

Adult↗
PubMed1983

[Bile peritonitis after inadvertent bladder puncture as a rare complication of percutaneous transhepatic cholangiography with the Chiba needle].

A report is given about a rare complication after percutaneous transhepatic cholangiography: after inadvertent puncture of the gallbladder, bile peritonitis developed. Surgery was done immediately and the gallbladder, which was filled with stones, as well as stones from the choledochus were removed. The literature dealing with complications of percutaneous cholangiography is reviewed.

Aged↗
PubMed1983

[Pathologic relations and diagnostic difficulties in pancreatic and gallbladder diseases following gastric surgery].

The authors studied the diagnostic possibilities of biliary and pancreatic diseases in patients after different types of operation of the stomach. In these cases, too, ERCP and PTC are suitable methods of examination. The authors studied 28 patients after gastric surgery: Billroth I gastrectomy: 6 cases, Billroth II gastrectomy: 21 cases and gastroenterostomy without gastrectomy: 1 case. Technical difficulties in connection with ERCP arose only with patients after Billroth II gastrectomy and the examination was successful in 67% only of the patients. The rate of successful examination of the bile duct system can be improved with the help of PTC. Apart from the technical difficulties, the analysis of the clinical material revealed data on the connections between gastric surgery and the development of biliary and pancreatic diseases. A few of these are well known in literature, but the traction and torsion of the duodenum during the preparation of the duodenal stump or gastroduodenostomy can also lead to the ductal deformity and the development of biliary and pancreatic diseases.

Adult↗
PubMed1982

[Chronic calcifying pancreatitis].

During the last 4 years, 34 patients with calcification in the pancreatic region are observed. The clinical data were analysed retrospectively and the significance of the chronic calcifying pancreatitis was studied. The occurrence of the disease is on the rise all over the world, caused above all by the spread of alcoholism. The pathogenic factors, epidemiology, clinical symptoms and questions of diagnosis, differentiation and therapy are discussed. In the diagnostic procedure the native abdominal X-ray film and the ERCP are the most important methods. The progress of chronic pancreatitis can be showed down and the complaints decreased with early diagnosis, adequate therapy and if the pathogenic factors (alcohol, bile stones etc.) are eliminated.

Adult↗
PubMed1981

[The clinical significance of juxtapapillary diverticula: endoscopic and radiological study (author's transl)].

The significance of duodenal diverticula is studied, in particular with respect to the supposed role of juxtapapillary diverticular in the development of biliary and/or pancreatic diseases. Duodenal diverticula were found in 72 cases with the help of duodenoscopy and ERCP, i.e. in altogether 1% of the patients investigated by upper GI endoscopy. On the basis of their observations and the data reported in the literature, the authors conclude that the pathological role played by juxtapapillary diverticula in the development of biliary and/or pancreatic diseases is by obstructing the pancreatic juice and bile flow. Stones are frequently found in the common bile duct in patients with juxtapapillary diverticula. At biliary surgery the observed diverticulum, which impedes biliary flow, must be taken into consideration, too. In such cases the aim of surgery is to guarantee free biliary flow, without which the operation cannot be considered successful.

Aged↗
PubMed1981

[Differential diagnostic possibilities of the liver and bile duct cysts (author's transl)].

The authors examined the diagnostical possibilities of the liver and bile duct cysts with different origin. On the base of the literature and own experiences surveyed the specific signs and the diagnostic value of peritoneoscopy, liver biopsy, scintigraphy, angiography, gray-scale ultrasonography, ERCP and PTC in the hepato-biliary cysts. GSU is the most suitable method to demonstrate the cystous character, but the connection with the biliary tract can be verified by ERCP. Peritoneoscopy is the best procedure in the diagnosis of the polycystic liver; the congenital liver fibrosis can be recognized by biopsy, only. The hepato-biliary cysts can be separated preoperative with the parallel adoption of these methods, in the majority of cases.

Bile Duct Diseases↗
PubMed1980

The effect of DDVP, an organophosphorus pesticide on the humoral and cell-mediated immunity of rabbits.

The effect of daily oral administration of LD50 1/40, 1/20 and 1/10 of an organophosphate pesticide DDVP (Dichlorvos) was studied in rabbits for its effect on the humoral immune response after vaccination with Salmonella typhi, as well as on cell-mediated immunity. Serum antibody titers of treated animals showed a dose-dependent fall compared with the controls. The skin redness measured in the tuberculin test showed the same dose-dependent tendency.

Animals↗