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Biomedical subjects

J Lukac

Publications and source records attributed to J Lukac.

47 records · Page 3Linked to original sources
PubMed1979

Mechanism of liquefaction of the human ejaculate. II. Role of collagenase-like peptidase and seminal proteinase.

Collagenase-like peptidase and seminal proteinase were isolated from human testis and human seminal plasma. The effects of both enzymes upon proteins isolated from the human ejaculate were studied. Both enzymes degraded ejaculate proteins. The data suggest that collagenase-like peptidase is responsible for the first, and seminal proteinase for the second, phase of human ejaculate liquefaction in vitro.

Chromatography, Gel↗
PubMed1977

The metalloenzymic nature of collagenase-like peptidase of the rat testis.

Collagenase-like peptidase, an enzyme degrading synthetic collagenase substrate (PZ-pentapeptide), was purified from rat testes and its properties were examined. Its activity was strongly inhibited by chelating agents, such as EDTA and 1,10-phenanthroline. By chelation and exhaustive dialysis it was possible to obtain this enzyme in its inactive, metal-free form. The activity of the metal-free enzyme was partly recovered by treatment with zinc or manganese ions, while a combined zinc and manganese treatment resulted in complete recovery of enzyme activity.

Animals↗
PubMed1976

Calcium-binding protein in bull seminal vesicle secretion and seminal plasma.

A protein which showed high affinity for calcium ions was isolated from bull seminal vesicle secretion and seminal plasma. Its calcium-binding activity depended on the ionic strength and pH of the medium. The dissociation constant was 7-7 X 10(-7) M and there were 14 binding sites per protein molecule. The molecular weight of calcium-binding protein from bull seminal vesicle secretion, estimated by the gel filtration method, was 110,000. The protein may be involved in the regulation of the calcium ion level in seminal plasma.

Animals↗
PubMed1975

The coagulation of insoluble and basic proteins from rat siminal vesicle secretion with vesiculase: influence of collagenase-like peptidase from rat testis.

Proteins from the secretion of rat seminal vesicles were fractionated to yield (i) insoluble protein, (ii) basic proteins (soluble in the presence of urea) and (iii) neutral plus acidic proteins. The first two are necessary for the formation in vitro of a coagulum which is very similar to the copulatory plug. Collagenase-like peptidase from rat testis degrades both protein fractions and prevents coagulum formation.

Amides↗
PubMedDate not supplied

Immunocompetent cells and lymphocyte reactivity to mitogens in levamisole-treated brain tumor children.

This study investigated the influence of levamisole therapy on immunocompetent cells and lymphocyte reactivity to mitogens in 25 children with brain tumor. Eleven (11/25) patients were receiving chemotherapy and immunomodulating drug levamisole 3 months after neurosurgery, during maintenance chemotherapy, 2.5 mg/kg of body weight per os, for three consecutive days every 2 weeks, for 6-12 months. The proportion of lymphocytes, proportion and number of T- and B-lymphocytes and natural killer (NK) cells, as well as lymphocyte reactivity to mitogens were significantly lower in non-levamisole-treated patients than in the healthy controls (N = 18). Therapy with levamisole significantly augments the proportion of T lymphocytes, the number of T lymphocytes, NK cells, and the lymphocyte reactivity to concanavalin A (Con A). Depression of the NK cells and the lymphocyte reactivity to mitogens were much more pronounced in those patients who developed recurrences. Levamisole shortened the period of secondary immunodeficiency in immunocompromised children with brain tumor.

Adjuvants, Immunologic↗
PubMedDate not supplied

Evaluation of genital human papillomavirus infections by polymerase chain reaction among Croatian women.

Infection with specific human papillomavirus (HPV) types is the strongest risk factor in cervical carcinogenesis. In this study we analysed, by means of polymerase chain reaction (PCR), cervical specimens obtained from consenting women with abnormal Pap smears collected from 1996 to 1998. Consensus- and type-specific-primers directed PCR were used in order to detect the presence and to determine the most common HPV types: 6, 11, 16, 18, 31 and 33. Out of 1874 specimens, 1207 (64%) contained one or more HPV types. Approximately half HPVs were typed (621 out of 1207) and the others remained untyped (586 out of 1207), 51% and 49%, respectively. Beside low-risk HPV 6/11 (5%), the most frequently observed HPVs were high-risk HPV types, especially type 16 (12%), while HPV types 18 (2%), 31 (5%) and 33 (3%) were less frequent. The HPV positivity rate declined with age, although all HPV types were equally distributed in different age groups. The presence of HPV DNA significantly increased from 55% to 78% along with the severity of the cervical lesions, i.e. low- and high-grade squamous intraepithelial lesions (LSIL, HSIL). Undetermined HPV types, other than 6/11, 16, 18, 31 and 33 were equally distributed in LSIL and HSIL which indicates that they represent low- as well as high-risk HPV types. Our results indicated that HPV infections, especially those with HPV 16, represent a significant public health concern in Croatia.

Adult↗
PubMedDate not supplied

[Interferon in the treatment of solid tumors].

Discovered almost four decades ago, interferons were being investigated as potential anticancer agents from early sixties, because of their antiviral antiproliferative and immunomodulating properties and their relatively modest toxicity. Unlike very good effects on some lymphoproliferative disorders where complete durable remissions were observed, results of their application in solid tumors are not so unambiguous. Among large number of tumors investigated so far, the best, reproducible, although modest, activity was found against melanoma, renal cell carcinoma and Kaposi's sarcoma. There are still many doubts concerning their optimal doses, sequencing and schedules, most probably in combination with other biological response modifiers and/or cytotoxic agents, which have to be clarified in further clinical trials, together with investigation of more reliable biological indicators of response to interferons in vivo.

Humans↗
PubMedDate not supplied

Neutrophil and monocyte phagocytic functions in patients with colorectal adenocarcinoma during fluorouracil therapy.

Neutrophil and monocyte phagocytic functions, i.e % of phagocytic cells, ingestion and intracellular microbe killing were determined in 51 patients with colorectal adenocarcinoma, 43 with localized disease and 8 with distant metastases. Phagocytic functions were determined at the time of diagnosis, following surgery are before each of 6 cycles of fluorouracil chemotherapy. Four of six phagocytic parameters determined were decreased at diagnosis while all 6 decreased following surgery. During chemotherapy, neutrophil phagocytic activity recovered to normal value while all other neutrophil and monocyte functions remained decreased. Even so, neutrophil ingestion and monocyte phagocytic and bactericidal activities increased reaching from time to time values significantly higher than that found before the start of chemotherapy. The results showed significant alterations of neutrophil and monocyte phagocytosis in colorectal adenocarcinoma patients at the time of diagnosis, with further decrease following surgery. Fluorouracil chemotherapy did not exert suppressive effects on these functions; on the contrary, it seemed to support, or at least not to prevent, their partial recovery.

Adenocarcinoma↗