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Biomedical subjects

S Murthy

Publications and source records attributed to S Murthy.

At least 109 records · Page 6Linked to original sources
PubMed1990

Phase Ia-Ib trial of an anti-GD3 monoclonal antibody in combination with interferon-alpha in patients with malignant melanoma.

A phase Ia-Ib study was undertaken to treat melanoma patients with a constant dose of the anti-GD3 monoclonal antibody, R24, in combination with increasing dose levels of recombinant interferon-alpha (rHuIFN alpha-2a). Fifteen patients were treated on days 1-5 and 8-12 with a continuous 6-h i.v. infusion of R24 (8 mg/m2) and escalating i.m. doses of rHuIFN alpha-2a. Peripheral blood lymphocytes were obtained at multiple times before and during treatment and monitored for changes in lymphocyte subpopulations and changes in natural killer and antibody-dependent cellular toxicity functional activity. There were no consistent changes in most immune parameters; however, there was a decrease from pretreatment levels in the suppressor T cell (CD8+, CD11b+) subset and a dose-dependent decrease in the helper/inducer (CD4+, Leu-8+) T cell subset. The peak serum concentration of R24 was reached on day 5 of the study and was 9.4 micrograms/ml. During the second week of treatment, peak serum levels of R24 fell to less than 4 micrograms/ml. This finding was related to the development of human antimouse antibody, which would be detected as early as day 8 of the study. Binding of mouse Ig (R24) within the tumor bed was observed in 5 of 12 biopsy specimens. The maximal tolerated dose of the combination was dose level IV, in which patients received 8 mg/m2 of R24 and 50 x 10(6) units of rHuIFN alpha-2a on days 1-5 and 8-12 of treatment.

Adult↗
PubMed1989

Phase I clinical trial of interleukin 2 and alpha-interferon: toxicity and immunologic effects.

Because recombinant interleukin 2 (rIL-2) and recombinant alpha-interferon (rIFN-alpha) exhibit synergistic antitumor activity in C3HMT1820 T-cell lymphoma and B16 melanoma tumor systems, we have performed a Phase I study of this combination in 55 patients with advanced malignancies for whom no standard therapy exists. Successive groups of greater than or equal to 4 patients have been entered into 12 dose levels (1A-3D), with dose levels 1-3 referring to doses of rIL-2 of 0.1, 0.5, and 2.0 x 10(6) units/m2, respectively, and dose levels A-D referring to doses of recombinant human alpha 2a-interferon (rHuIFN-alpha 2a) of 0, 0.1, 1.0, and 10.0 x 10(6) units/m2. Both agents were given on Mondays, Wednesdays, and Fridays, with rIL-2 being given as i.v. bolus injections and rHuIFN-alpha 2a being given intramuscularly. Myelosuppression was dose-limiting and was related primarily to the dose of rHuIFN-alpha 2a. The maximum-tolerated dose level was reached at a dose of rIL-2 of 2.0 x 10(6) units/m2 and of rHuIFN-alpha 2a of 10.0 x 10(6) units/m2 (dose level 3D). At this dose level, 3/6 patients developed grade 3 neutropenia (absolute granulocyte count less than 1 x 10(9)/liter). Myelosuppression was transient, with no documented infections being associated with neutropenia. Hypotension was mild; a single patient was treated with a vasopressor, but all other cases of hypotension responded to fluid administration. No significant pulmonary toxicity was produced. Fever, chills, and malaise were universal but not dose-limiting. Three partial responses and one minor response were observed in patients with malignant melanoma, renal cell carcinoma, and breast cancer. Immunological studies suggested that natural killer activity was related to both the dose of rIL-2 and the dose of rHuIFN-alpha 2a, with natural killer activity being positively related to the dose of rIL-2 and maximal at the lowest dose of rHuIFN-alpha 2a of 0.1 x 10(6) units/m2.

Adult↗
PubMed1989

Effects of phospholipid or cholesterol enrichment of rat intestinal brush border membrane on membrane order and transport of calcium.

Calcium uptake by brush border membrane vesicles from rat small intestine measured under initial rate conditions comprises both saturable and nonsaturable components. Because the brush border is a lipid bilayer and may be sensitive to changes in membrane lipid, vesicles were treated with liposomes to enrich phospholipid (PL) or cholesterol (C) content above that of the control (Reference) vesicle. The effects of the changes in lipid composition on membrane fluidity were determined from fluorescence anisotropy (r) of diphenylhexatriene. Compared with Reference vesicles, liposome-treated vesicles showed decreased Vmax for saturable and KD for nonsaturable uptakes. Liposome treatment changed vesicle phospholipid composition compared with Reference vesicles. Liposome-treated vesicles had similar phospholipid composition but differed in greater cholesterol content of C- compared with PL-vesicles. Mean Vmax and KD were lower in C- than PL-vesicles, but the difference did not reach statistical significance, although fluidity was significantly lower in C- than PL-vesicles. The mechanism of inhibition of saturable calcium uptake in PL- and C-vesicles was uncompetitive. Thus, lipid composition is crucial for determining calcium uptake: any change from native lipid composition decreased transport. Fluidity, measured by the conventional probe diphenylhexatriene, did not correlate with calcium uptake by Reference compared with liposome-treated vesicles.

Animals↗
PubMed1989

SpermCheck: a simplified screening assay for immunological infertility.

SpermCheck (Bio-Rad Laboratories, Hercules, CA), a new screening test for regional surface antibodies on motile sperm, uses monodispersed latex microspheres of uniform size as a vehicle to link rabbit antihuman immunoglobulins (IgA, IgG, IgM) and provides both negative and positive control sera, as well as sufficient buffer for sperm preparation in ambient CO2 atmosphere. When compared with reference data available for the immunobead test (IBT), the direct protocol (semen) for SpermCheck yielded 94.4% sensitivity with 100% specificity; the indirect protocol (serum) provided a sensitivity of 100% with 94.7% specificity. The microspheres of SpermCheck maintain a nearly uniform concentration per volume, with none to negligible clumping. The greater difference between the optical densities of latex and cytoplasm allows use of a light microscope for the rapid assessment of the percent of regional binding rather than the phase-contrast microscope required for the IBT. SpermCheck eliminates many difficulties encountered with the IBT, making SpermCheck a convenient screening assay for use in the physician's office.

Antibodies↗
PubMed1988

Ultra-short-acting beta-adrenergic blockers.

The ultra-short-acting beta-adrenergic blockers are parenteral agents that can be rapidly titrated in clinical situations where immediate beta-adrenergic blockade is warranted. The effects of those drugs rapidly dissipate after termination of treatment, providing an important safety feature. Esmolol, the prototype drug of this class, is approved for treatment of supraventricular tachyarrhythmias but also has potential use in treatment of patients with perioperative hypertension and acute myocardial ischemia.

Adrenergic beta-Antagonists↗
PubMed1988

Modification of CaCo-2 cell membrane fatty acid composition by eicosapentaenoic acid and palmitic acid: effect on cholesterol metabolism.

Membrane fatty acid composition of CaCo-2 cells was modified by incubating the cells for 8 days in medium containing 100 microM eicosapentaenoic acid or palmitic acid. The effect of membrane fatty acid changes on cholesterol metabolism was then studied. Cells incubated with eicosapentaenoic acid had significant changes in membrane fatty acid composition with an accumulation of 20:5 and 22:5 and a reduction in monoenoic fatty acids compared to cells grown in palmitic acid. Intracellular cholesteryl esters could not be detected in CaCo-2 cells grown in the presence of the n-3 polyunsaturated fatty acid. In contrast, cells incubated with the saturated fatty acid contained 2 micrograms/mg protein of cholesteryl esters. Cells grown in eicosapentaenoic acid, however, accumulated significantly more triglycerides compared to cells modified with palmitic acid. The rate of oleic acid incorporation into triglycerides was significantly increased in cells incubated with eicosapentaenoic acid. CaCo-2 cells modified by eicosapentaenoic acid had lower rates of HMG-CoA reductase and ACAT activities compared to cells modified with palmitic acid. The incorporation of the two fatty acids into cellular lipids also differed. Palmitic acid was predominantly incorporated into cellular triglycerides, whereas eicosapentaenoic acid was preferentially incorporated into phospholipids with 60% of it in the phosphatidylethanolamine fraction. The data indicate that membrane fatty acid composition is significantly altered by growing CaCo-2 cells in eicosapentaenoic acid. These modifications in membrane fatty acid saturation are accompanied by a decrease in the rates of cholesterol synthesis and cholesterol esterification.

Adenocarcinoma↗
PubMed1987

In vivo identification of multiple promoter domains of adenovirus EIIA-late promoter.

The transcriptional control elements of the Adenovirus (Ad) type 5 EIIA-late (L) promoter were analyzed in the context of the viral chromosome. Promoter mutants constructed in vitro [deletion and linker-scanning (LS)] were re-introduced into the non-essential EIII region of an Ad5 variant which lacked the EIA gene. They were then analyzed in human 293 cells for EIA-dependent and in HeLa cells for EIA-independent transcription. These studies revealed that a minimum of approximately 157 bp upstream from the Cap site are sufficient for the efficient transcription of this promoter in the presence or absence of the EIA gene products. Within the 157-bp sequence, multiple control elements can be identified. These are (i) a sequence block between -55 and -21 which contained a sequence resembling the TATA box and an Sp1 recognition site 5'-TGGGCGTGGT-3', (ii) a sequence block between -84 and -67 which contained a second Sp1 recognition sequence, 5'-CGGGCGGGAT-3' and a 5'-CCAAT-3' box in the non-coding strand and (iii) a 56-bp sequence block between -157 and -101 which contained a 5'-CCAAT-3' sequence in the non-coding strand. The transcriptional pattern of the LS mutants in 293 cells was very similar to that of HeLa cells suggesting that neither of the EIA gene products interact with EIIA-L promoter directly to modulate transcription. A purified Sp1 protein protected DNA sequences from -56 to -33 which includes the Sp1 recognition sequence closer to the cap site whereas the distal Sp1 recognition sequence showed a very weak affinity for the Sp1 factor.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenovirus Early Proteins↗
PubMed1986

Viral-encoded small RNAs in herpes virus saimiri induced tumors.

DNA sequences from the left terminus of herpes virus saimiri L-DNA are essential for the oncogenic and transforming potential of the virus, but these sequences are not required for replication. RNA derived from 0.0 to 6.7 map units (7.4 kbp) on the herpes virus saimiri genome was studied by Northern blot hybridization and by nuclease protection analyses. Although several poly(A)-containing RNAs were detected from this region in permissively-infected monolayer cells in vitro, these RNAs could not be detected in cells taken directly from viral-induced lymphomas nor in the lymphoblastoid tumor cell line 1670. Instead, these transformed T-cells expressed four small RNAs of approximately 73, 105, 110 and 135 nt derived from this region. These small RNAs were not detected at all during the course of lytic infection of monolayer cells. Thus, synthesis of these RNAs is stringently regulated in a cell-type specific manner. Genomic coding sequences for each of these small RNAs were mapped to 0.5-1.2 kbp DNA fragments stretched over 4.3 kbp of viral genetic information. These findings together with the biological properties of mutants with deletions in this region have led us to speculate that one or more of these small RNAs play an essential role in cell growth transformation by herpes virus saimiri.

Animals↗
PubMed1985

Additive cytotoxicity of adriamycin and a naturally occurring growth inhibitor extracted from bovine aorta.

A factor of nominal molecular weight 6K-10K Daltons, isolated from bovine aorta, has previously been shown to inhibit neovascularization and tumor growth in vivo and the growth of some tumor cells as well as endothelial cells in culture. This factor, termed A-10, was tested alone and in combination with Adriamycin against TA3Ha mammary adenocarcinoma cells in tissue culture. It was found to have cytotoxicity additive to that of Adriamycin in inhibiting the growth of these cells. In vitro and animal studies show that the sequence of Adriamycin----A-10 is superior to either agent alone in delaying the appearance of palpable tumors after subcutaneous injection of 10(5) pre-treated tumor cells in the tail of strain A mice. While the growth rate of the primary tumor was not affected by such treatment, survival was prolonged to a greater degree by the this sequence than by either of these agents used alone. A-10 treatment reduced the number of metastases to the adrenal gland but not to lung, liver, or lymph nodes. It did, however, reduce the size of metastases to para-aortic lymph nodes.

Animals↗
PubMed1979

Aarskog syndrome: significance for the surgeon.

A familial syndrome of short stature associated with facial dysplasia and congenital anomalies was reported by Aarskog in 1970. Subsequently, at least 53 patients in 13 affected families have been reported. The family to be described came under investigation following referral of one of the nine siblings to the surgical clinic at Childrens Hospital of Los Angeles for the evaluation of a right inguinal hernia. Recognition of the syndrome and further evaluation of the remaining siblings led to the diagnosis of several genital anomalies requiring surgical correction.

Abnormalities, Multiple↗
PubMedDate not supplied

A dual role for involucrin in the epidermis-ultrastructural localization in epidermis and hair follicle in humans and transgenic mice.

Transgenic mice expressing human involucrin (hINV) have an abnormal hair coat appearance. To understand this phenotype, we used immunoelectron microscopy to examine hINV distribution in the hair follicle and epidermis. In human epidermis, hINV is first observed in the cytoplasm of spinous and granular layer cells. In transition cells, it is equally distributed between the cytoplasm and the nascent cornified envelope, while in the corneocytes it is largely cornified envelope-associated. In transgenic mice, the pattern of expression is similar except that much more antigen appears to be present. An important finding is the presence of hINV in hair follicle structures--low levels in the hair and high levels in the inner root sheath (IRS). The distribution of hINV is comparable in human and transgenic mouse follicles; however, much higher levels are observed in the mice. In contrast, hINV is not detected in cells of the outer root sheath (ORS). Thus, hINV is differentially expressed in two related and contiguous tissues, the epidermis and the ORS. Based on these results we conclude that hINV is a specific product of differentiated IRS cells that is localized at the cell envelope, suggesting a function as a cross-linked constituent of IRS cell envelope. These results suggest that hINV may have a dual role in epidermis, as a cross-linked structural protein in the epidermal corneocyte and the hair follicle IRS.

Animals↗
PubMedDate not supplied

Phase II trial of circadian infusion floxuridine (FUDR) in hormone refractory metastatic prostate cancer.

Circadian administration of chemotherapy has been reported to decrease toxicity and possibly enhance efficacy. Between March 1991 and December 1993, 18 evaluable patients with progressive, hormone-refractory metastatic prostate cancer were treated in this phase II trial of circadian infusion floxuridine (FUDR). The drug was delivered through a central venous catheter using a CADD-Plus computerized pump such that approximately 70% of the drug was administered between 3 and 9 p.m. and the rest (30%) was administered between 9 p.m. and 3 p.m. The dose of FUDR was 0.15 mg/kg/day x 14 days every 4 weeks. A total of 79 complete cycles was administered. Two of 18 evaluable patients (11.1%) had decreases in PSA lasting five and eight months. No objective responses or improvement in bone scans was noted. The major toxicity observed was diarrhea. Although circadian infusion FUDR is feasible and tolerable, it has limited activity in hormone refractory prostate cancer.

Antimetabolites, Antineoplastic↗