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Biomedical subjects

F Fabian

Publications and source records attributed to F Fabian.

At least 19 recordsLinked to original sources
PubMed1989

[The importance of early cholecystectomy in cholelithiasis for the prevention of carcinoma of the gallbladder].

The authors report on a series of 324 patients operated on for cholelithiasis. They summarize the histological findings obtained by detailed examination of the surgical specimens carried out by one pathologist. The relatively high rate (43%) of severe pathological changes in the gallbladder wall in emphasized as these may be sites of predilection for the development of carcinoma. Three cases of only histologically established carcinoma are briefly described. In two of them carcinoma developed on the basis of chronic fibroproductive cholecystitis. In the third case the gall bladder was not removed and thus histologically not examined. In the light of their findings, the authors strongly advocate early cholecystectomy, particularly in patients of advanced age groups.

Adult↗
PubMed1984

Effect of nucleotides, divalent cations and temperature on the tryptic susceptibility of myosin subfragment 1.

The kinetics of tryptic breakdown of the heavy chain of chymotryptic myosin subfragment 1 (S1) according to the following scheme (where the numbers represent approximate masses in kDa) are altered at 21 degrees C by divalent (Formula: see text) cations (Me2+) and by ATP, ADP, adenosine 5'-[beta, gamma-imino]triphosphate or PPi, with or without Me2+. ATP or its analogs slow step 2 and accelerate steps 3 and 4, while Me2+ accelerates step 2. ATP and its analogs decrease the amount of a transient 27-kDa peptide [Hozumi, T. & Muhlrad, A. (1981) Biochemistry 20, 2945-2950]. We have found direct evidence for the suggestion in this reference that the 27-kDa peptide is not an obligatory precursor of the 25-kDa fragment and that ATP or ADP suppresses the formation of the larger N-terminal fragment rather than accelerates its breakdown. Cross-linking of sulfhydryl groups located in the 20-kDa fragment leads to trapping of MgADP in the N-terminal 25-kDa peptide [Wells, J.A. & Yount, R.G. (1980) Biochemistry 19, 1711-1717]; this process affects the tryptic fragmentation of S1 similarly to, but less effectively than, nucleotides. Acts-S1 formation prevents the effect of ATP on fragmentation. At 37 degrees C S1 loses ATPase activity; tryptic digestion proceeds more rapidly and the 50-kDa and 25-kDa fragments are degraded to small peptides. Nucleotides protect against the effects of higher temperature by producing conformational changes not only in the 27-kDa N-terminal portion (containing the putative nucleotide binding site) of the heavy chain of S1 but also in the 50-kDa peptide.

Actomyosin↗
PubMed1980

Freezing and thawing of myosin with no alteration in ATPase activity.

Myosin can be frozen in liquid nitrogen (-70 degrees C) and stored at this temperature for 5 months with no loss in K+, Ca2+, or actin + Mg2+ -stimulated ATPase activities. Furthermore, myosin can be refrozen and thawed in this manner for at least 5 consecutive times with no alteration in ATPase activity.

Actins↗
PubMed1980

Epilepsy and complication after craniocerebral traumas.

Three hundred and seventy-two patients aged from 24-80 years were examined 10-15 years after past craniocerebral trauma. Of that number 355 subjects had concussion and 17 subjects brain contusion. Posttraumatic epilepsy was diagnosed by 8 cases (2.15%) only. It affected 4 females, aged from 40-60 years, and 3 males aged 30-48 years after the brain concussion, as well as 1 man, 30 years old, after the brain contusion. That first epileptic attack in 4 cases occurred after the lapse of 1-2 years, in 3 persons after the lapse of 6-10 months, and 1 patient having had brain contusion after 4 months. All posttraumatic patients were treated prophylactically with phenobarbital 0.1 twice a day for a period of several weeks.

Adult↗
PubMed1979

Comparison of Mg2+ vs Ca2+, K+ and actin-activation of myosin after trinitrophenylation.

While modification of six lysyl residues causes a near maximal decrease in Ca2+, K+, and actin + Mg2+ -activated myosin ATPase activities in rabbit skeletal muscle myosin, it takes nearly twice this number of modified lysyl groups to cause a similar alteration in canine cardiac myosin where trinitrophenylation is nonspecific. It appears that there are several rapidly reacting lysyl residues in cardiac myosin; the active site of cardiac myosin is protected by ATP after modification of a limited number of these rapidly reacting lysyl groups. In both myosins, after a charge modification of these rapidly reacting lysyl groups, 6 in rabbit skeletal muscle myosin and 10 in canine cardiac myosin, there is a decrease in Ca2+, K+, and actin + Mg2+ -stimulation of myosin but an activation of Mg2+ -stimulated myosin ATPase activity, thus making actin + Mg2+ -stimulated myosin ATPase activity more like activation with K+ or Ca2+ as compared to activation with Mg2+ alone.

Actins↗
PubMed1977

Relationship of age and sex to postheparin esterase activity.

Postheparin esterase (E. C. 3.1.1.1.) activity was studied in 130 women and 126 men in whom the medical findings were consistent with their age. The test subjects were divided into 5 age groups from 17 to 73 years. Postheparin esterase activity was found to be statistically significantly higher in men than in women. In men it was uncorrelated to age, while in women it rose with advancing age. Changes in postheparin esterase in women appear to be correlated to the hormonal state of the organism.

Adolescent↗
PubMed1976

Microheterogeneity in porcine pancreatic amylase preparations due to disulfide-sulfhydryl exchange.

There are two masked SH groups in pancreatic amylase (EC 3.2.1.1) which become reactive after removal of Ca ions, and then only due to fluctuation of the polypeptide chain. Carboxymethylation of the masked SH groups and isolation of the tryptic CM-peptides have shown that the reacting SH groups in active amylase preparations are not identical, depending on the method of preparation. The microheterogeneity is attributed to an SH-SS exchange reaction taking place during preparation. This exchange results in a mixture of two types of amylase molecules containing different SH groups. The tryptic peptides containing the SH groups have been detected from the radioautogram of the peptide may of the [14C] carboxymethylated protein digest. We identified the SH peptides present in native amylase, and those cysteinyl peptides which form an easily reducible disulfide in the vicinity of these thiol groups, and take part in the intramolecular SH-disulfide exchange.

Amylases↗