FSH-induced aromatase activity in porcine granulosa cells: non-competitive inhibition by non-aromatizable androgens

The aim of this study was to examine the inhibitory effect of the non-aromatizable androgens on FSH-stimulated aromatase activity in porcine granulosa cells. The cells were isolated from medium-sized follicles (4-6 mm) of prepubertal pigs, and cultured under chemically defined conditions in the presence of FSH (1 microgram/ml, NIADDK-oFSH-S13) with and without the androgens for an initial 48-h induction period. Subsequently, the spent medium was replaced with fresh medium containing only testosterone as substrate and the cells were reincubated for a further 6 h. The conversion of this steroid to oestradiol-17 beta during this latter 'test' period was taken as a measure of the aromatase activity. The addition of 5 alpha-dihydrotestosterone (DHT) into cultures of FSH-stimulated cells during the induction period resulted in a definite dose-dependent inhibition (30-70%) of the aromatase activity expressed in the test period. This inhibitory action, of the mixed non-competitive type, is characterized by a decrease in the apparent Vmax and an increase in the Km value, suggestive of an androgen inhibition of FSH-stimulated aromatase synthesis. This inhibition was also shown by the other 5 alpha- and 5 beta-reduced androgens: 5 beta-androstanedione was the most effective, while DHT was the least. Other steroids such as pregnenolone and progesterone were inhibitory, but testosterone and diethylstilboestrol were stimulatory. These results suggest an important mechanism for the intrafollicular control of oestrogen synthesis, involving a possible reciprocal relationship between aromatase and 5 alpha-reductase activities.

Resurgence of hemorrhagic disease of the newborn: a report of three cases

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Fast diffusion along defects and corrugations in phospholipid P beta, liquid crystals

The diffusion of a fluorescent lipid analogue in liquid crystals of the anisotropic P beta, phase of dimyristoylphosphatidylcholine (DMPC) had been found to be highly variable, suggesting structural defect pathways. Fluorescence photobleaching recovery (FPR) experiments imply two effective diffusion pathways with coefficients differing by at least 100. This is consistent with fast diffusion along submicroscopic bands of disordered material ("defects") in the bilayer corrugations characteristic of this phase. Due to strains during transformation from the L alpha phase, the axis of the corrugations is ordinarily disrupted by mosaic patches rotationally disoriented within the mean plane of the molecular bilayers, although larger oriented domains are sometimes adventitiously aligned into microscopically visible striped textures. The corrugations are also systematically aligned along positive disclinations pairs or "oily streaks." Thus, fast diffusion occurs parallel to the disclination lines and along the textured stripes. FPR results yield an upper limit on the effective diffusion in the ordered material of D less than or equal to 2 X 10(-16) cm2/s at 22 degrees C, D less than or equal to 3 X 10(-17) cm2/s at 13 degrees C. In contrast the diffusion coefficient along defect pathways where disordered ribbons are aligned is D approximately 4 X 10(-11) cm2/s at 16 degrees C.

Alternating non-cross-resistant combination chemotherapy for small cell anaplastic carcinoma of the lung

The development of drug resistance limits the survival or patients with small cell anaplastic carcinoma of the lung (SCLC). The present study was undertaken to overcome this problem by administering two alternating noncross resistant combination chemotherapy regimens. One-hundred-one patients were entered on study, and 98 were evaluable, with a median onstudy time of 55+ weeks. All patients received the initial combination therapy of cyclophosphamide, methotrexate, and vincristine, alternating every three weeks with Adriamycin and VP16-213 (etoposide). Radiation therapy was not a standard part of protocol. Thirty-two patients had regional disease (LD), and 66 had extensive disease (ED). Overall, 76% of patients responded to this therapy with 30 (31%) complete remission (CR) and 44 (45%) partial remissions (PR); the respective CR and PR rates were 31% and 50% for LD, and 30% and 42% for ED patients. Myelosuppression was the principal toxicity with a leukocyte nadir of 2.0 X 10(9)/1 in 10% of cycles. Septicemia in six neutropenic ED patients with progressive disease contributed to the only treatment-related deaths. Patients entering CR had a median survival greater than 51 weeks (range, 8-150+); 58+ for LD and 49+ for ED patients. Patients in PR had respective median survivals of 33+ (overall), 43+ (LD), and 24+ (ED) weeks. Forty patients have had relapses with initial sites being local sites in 35%, and neurologic in 38%. Although this protocol has not discernibly delayed the onset of drug resistance, the problem should be considered when new protocols are designed in SCLC.

Four-drug combination chemotherapy for advanced cervical carcinoma

Thirty-one patients with advanced stage squamous cell carcinoma of the cervix were treated with the four-drug combination fluorouracil, doxorubicin, cyclophosphamide, and vincristine. Four patients achieved complete remission (13%) and 15 partial remission (45%). The only factor of adverse prognostic significance was poor initial patient performance. Median survival for the patients entering complete remission exceeded 54 weeks and was 43 weeks for patients achieving partial remission. Seven patients are still alive at 50 weeks. This represents a notable prolongation of survival compared with those patients who did not achieve remission. Toxicity for the combination was not excessive; myelosuppression and vincristine-induced neuropathy were the most prominent. These results are moderately encouraging and confirm the sensitivity of cervical carcinoma to systemic chemotherapy. Further studies to define the optimal use of chemotherapy in both advanced and earlier stages of disease are warranted.

Meningeal carcinomatosis in small cell carcinoma of the lung

Cerebral and meningeal metastases are increasingly important complications in small cell anaplastic carcinoma of the lung. In a study at this institution, 60 evaluable patients received intensive chemotherapy without prophylactic cranial irradiation or other prophylactic measures. The complete plus partial remission rate was 78 percent with a median survival of 49+ weeks (range eight to 106+ weeks) for those with a complete response and 18+ weeks (range six to 67 weeks) for those with a partial response, all of which are comparable to other reported series. In 11 patients (18 percent) meningeal carcinomatosis has developed. Forty-two percent of the patients with a relapse have exhibited meningeal carcinomatosis and in 27 percent of the patients with a relapse it was the only site of relapse. Cerebral metastases occurred in 27 percent of those who had a relapse, and in 12 percent this was the sole site of relapse. Simultaneous meningeal carcinomatosis and cerebral metastases occurred in 8 percent of the patients with a relapse. The median time to meningeal relapse was 27 weeks (range 12 to 60 weeks) compared with 25+ weeks (six to 106+ weeks) over-all, and the median survival was 28 weeks (range 14 to 82 weeks) compared with 25+ weeks (two to 106+ weeks) for the whole group with small cell carcinoma of the lung. Meningeal involvement in small cell carcinoma of the lung must now be considered a sanctuary site of equal importance to cerebral metastases. To prevent and treat this complication will necessitate evaluation of all available modalities, including cranial and spinal irradiation, intrathecal chemotherapy and systemic agents that readily cross the blood-brain barrier.

Methyl-CCNU, 6-thioguanine, and 5-fluorouracil in advanced colorectal cancer

Consecutive studies were undertaken in advanced colorectal adenocarcinoma, comparing two different schedules of the combination methyl-CCNU, 6-thioguanine, and 5-fluorouracil in 89 patients. The two schedules exhibited similar efficacies, with a combined complete and partial remission rate of 17%, a median response duration of 36+ weeks, and a median survival of 53+ weeks. Significant symptomatic benefit was seen in 52% of patients. Toxicity was predominantly hemopoietic and gastrointestinal, being acceptable overall, with only minor qualitative differences between the two protocols. These triple-drug regimens exhibit response rates and survival patterns comparable with those reported for other multidrug combinations and some single agents. It would appear that major improvements in the management of advanced-stage disease must await the availability of more efficacious agents used alone or in combination.

Industrial development and health in Malaysia

Industrial development in Malaysia is discussed in relation to impact on health. Trends in Malaysia are evaluated and the findings of some studies in Malaysia are reviewed.

Water and hermal diffusivity in a lipid-water smectic phase

We report the first application of light scattering to measurement of the hydrodynamic relaxation of inhomogeneities in water concentration within a multilamellar, or smectic A, phospholipid water system (dipalmitoyl) phosphatidyl choline). Although the relaxation process in the multilamellar phase is different from the diffusion process in liquid phases, the relaxation rate can be described in terms of a diffusion coefficient. For diffusion parallel to the lamellae, diffusion coefficients ranging from 8 x 10(-7) to 2 x 10(-5) cm2/s were measured over a range of temperature and water concentrations. We describe a model that expresses the diffusion coefficient in terms of the chemical potential for water inside the multilamellar phase and the effective thickness of a "free water zone." The deduced thickness of this free water zone is in good agreement with estimates from X-ray diffraction results. The activation energy for the diffusion process is also deduced from the data, and is found to decrease monotonically with increasing water concentration. We also found the thermal diffusivity to be about 10(-3) cm2/s with only a weak temperature and water concentration dependence. The experimental technique is a new version of forced Rayleigh scattering. The method uses the phase information of the scattered light to improve the ability to detect weak signals. Experimental details are reported.