Effect of 60 degrees head-up tilt on systolic time intervals in hypertensive patients.

Time course of systolic time interval (STI) variations during 60 degrees head-up tilt (HUT) was studied in 21 patients with essential hypertension and equal number of age-matched control subjects. ECG, Phonocardiogram and carotid pulse were recorded simultaneously on polygraph. Electromechanical systole (QS2), left ventricular ejection time (LVET), pre ejection period (PEP), PEP/LVET ratio and ejection fraction (EF) were determined immediately after and at 1, 2, 3, 4 and 5 min after the tilt. In hypertensive patients, basal values of PEP and PEP/LVET ratio were insignificantly higher whereas LVET and EF were insignificantly lower as compared to the control subjects. 60 degrees HUT produced significant decrease in LVET (P < 0.001) and EF (P < 0.001) and a significant increase in PEP/LVET ratio (P < 0.001) in control subjects. The changes in hypertensive subjects were similar in pattern but statistically insignificant. It is concluded that tilt-induced changes in STIs are blunted in hypertensive patients.

Detection of breast tumor associated mucin epitope on CAMA cell line using monoclonal antibody G3F1 generated against HMFG membrane.

The expression of breast tumor associated mucin epitope on CAMA cell line was detected employing the mouse MAB G3F1 generated against HMFG membrane. Immunocytochemical studies revealed that MAB G3F1 strongly reacted with 85% of breast cancer tissue sections with specific staining of apical cell membrane of malignant epithelial cells. The mucin antigen recognised by MAB G3F1 was detected by selectively extracting high molecular weight glycoprotein antigen from HMFG membrane using lectin affinity chromatography and gel filtration chromatography. Immunoprecipitation studies revealed that MAB G3F1 recognized a high molecular weight glycoprotein with an approximate molecular weight of 300kd. The expression of MAB G3F1 reactive antigen on CAMA cells was detected by immunocytochemistry and by immumoprecipitating 300kd antigen from 125I labelled Tx100 solubilized extract of CAMA cells. The results from these investigations suggest that CAMA cells express MAB G3F1 reactive antigen with tumor associated epitope, similar to tumor associated mucin epitope of HMFG membrane.

Anti-tumor activity of monoclonal antibody CIBCNSH3 generated to the human EGF receptor.

The overexpression of the human epidermal growth factor receptor (EGFR) has been demonstrated in many malignancies like squamous cell carcinoma of the head and neck, cervix, breast etc. which are most prevalent in India. This is often associated with poor prognosis and high mortality in these patients. Monoclonal antibodies generated against EGFR which inhibit binding of ligands like EGF to their receptor have anti-tumor activity and hence therapeutic application. One such monoclonal antibody designated as CIBCNSH3 generated in our laboratory has been found to recognize an epitope in the extracellular domain of EGFR by immunoprecipitation. By immunoperoxidase test this antibody exhibited strong reactivity to EGFR in head and neck cancers and breast cancers studied. It also inhibited the binding of Epidermal Growth Factor (EGF) to its receptor on MDA MB468 breast cancer cells rich in EGFR as revealed by competitive binding assay using 125I EGF, indicating its anti-tumor activity. The in vivo therapeutic efficacy has been demonstrated by injecting i.p. into tumor bearing mice 200 micrograms of the antibody for 4 consecutive days and then 100 micrograms twice a week resulting in complete regression of tumors of initial tumor size of 0.5-1.0 cm diameter. These results were compared with a control antibody against EGFR and also a nonspecific antibody which were administered to different groups of animals. In vivo studies performed using cell lines in culture like MDA MB468, MDA MB157 and HN5 with overexpression of EGFR revealed 98% cell death when incubated with different concentrations of the antibody. This monoclonal antibody seems to have a promising future application as therapeutic agent for tumors which overexpress EGFR.

Isolation of heparan sulfate proteoglycan from beneath the monolayers of rat hepatocytes and its binding to type IV collagen.

Primary cultures of rat hepatocytes maintained as monolayer in a serum-free medium synthesise and secrete sulphated proteoglycans. Nearly 5% of the total 35(S)-sulphated material was obtained in a soluble form from beneath the cell layer. A shift in gel filtration pattern on beta-elimination with alkali suggested that it is a sulphated proteoglycan. On ion exchange chromatography over Dowex AG 1 x 2, the major fraction was eluted with 1.25 M NaCl. Further, nearly 80% of the 35(S)-labeled material was susceptible to nitrous acid degradation and more than 90% of the material was resistant to chondroitinase ABC digestion suggesting that it is predominantly a heparan sulphate proteoglycan (HSPG). Since HSPG is a major component of basement membrane, its binding with collagen was studied by a solid phase binding assay. About 75% of the 35(S) HSPG bound to wells coated with type IV collagen whereas only about 20% bound to type I collagen at physiological pH. Binding to collagen IV was reduced by about 50% when free GAG chains were used indicating that the protein core is also involved in interaction with the collagen. These results indicate the possible role of this basal extracellular heparan sulphate proteoglycan in the basal lamina formation.