Effects of cytoskeletal inhibitors on the accumulation of vincristine in a resistant human lung cancer cell line with high level of polymerized tubulin

We have previously established a vincristine resistant human lung cancer cell line (PC-9/VCR) by a stepwise exposure of parental line PC-9 to vincristine. In this study the resistant cells showed enhanced vincristine cytotoxicity in the presence of cytochalasin B and D. The increase in cytotoxicity was associated with an enhanced accumulation and a reduced efflux of vincristine. Colchicine and taxol had no effects on vincristine accumulation. Several cytoplasmic proteins were overexpressed in the resistant cells. The two major ones, with molecular weights of 58.8 kDa and 83.2 kDa, were shown by western blotting to be beta-tubulin and actin, respectively. The polymerized tubulin level in the resistant cells was significantly (p < 0.05) higher than that in the parental cells. These results suggest that the cellular cytoskeletons might play an important role in VCR resistance in the PC-9/VCR human lung cancer cell line.     

Improved autonomic neurocardial balance in short-term abstinent alcoholics treated with acamprosate

Standardized investigations on resting heart rate variability (HRV) should provide more information on acamprosate's human pharmacodynamic properties because acamprosate interacts with several neurotransmitter systems which are also involved in maintaining autonomic neurocardiac balance. We performed HRV measurements prospectively in 69 healthy controls and 19 chronic alcoholics to prove the hypotheses that: (1) compared to healthy controls, chronic alcoholics show disturbances in neurocardiac vagal function; and (2) in alcoholics, acamprosate treatment (6-8 days) should further decrease parasympathetic activity if acamprosate interacts with central gamma-aminobutyric acidA receptors in vivo. Cardiovagal dysfunction was initially present in 21% of the alcoholics. After treatment. however, their neurocardiac sympathetic-parasympathetic balance improved significantly.     

Steroid biosynthesis in the whelk, Buccinum undatum

Cell-mediated immunity (CMI) to homologous spermatozoal antigens was studied in sixty-two males following vasectomy of a duration of 1-10 years. A group of twenty-two normal, fertile non-vasectomized males was also included in the study. The inhibition in the leucocyte migration test (LMT), in the presence of spermatozoal antigen, was taken as an index of CMI. Twenty of the sixty-two vasectomized males (32.2 percent) showed a positive LMT reaction. When the results were analysed with reference to the duration of vasectomy, it was noted that four cases each (22.2 percent), showed a positive LMT reaction in the groups 0-2 years, and 3.5 years. On the other hand twelve cases gave a positive reaction in the group 6-10 years (46.1 percent). It appears that the incidence of CMI to spermatozoa increases with the duration in vasectomy.     

Electrical properties of pig colonic mucosa measured during early post-natal development

Microvillar membrane (Vm) and transmural (Vt) potential differences were measured in proximal colon taken from pigs at birth and up to 10 days of age. 2. Vm remained independent of the age of the animal provided it was measured in the absence of methionine. The over-all mean was -43-3 mV. Adding methionine to fluid bathing the mucosal surface of new-born pig colon caused a 9-8 mV depolarization of Vm and a 6-7 mV increase in Vt. These effects, which were Na+-dependent, were not seen in the 10-day-old animal. 3. Substituting SO4(2-) for Cl- in methionine-free medium caused a hyperpolarization in Vm. Increasing the concentration of K+ caused corresponding depolarization. Substituting choline for Na+ had no effect on VmCl- and K+ movement across the microvillar membrane together account for the bulk of the measured membrane potential. These results apply to all stages of development. 4. Na+ uptake across the microvillar membrane of the new-born pig colon was increased in the presence of methionine. This effect disappeared in older animals. Na+ uptake in the absence of methionine doubled during the first 24 h of post-natal life. This increase was maintained using colons taken from older animals. 5. Methionine depolarization of Vm in the new-born pig colon is probably caused by the electrogenic influx of Na+. The ability of the colon to actively concentrate methionine within tis mucosa disappears at the same time as methionine ceases to affect Vm and Vt. It is suggested that methionine and Na+ form a ternary complex with a carrier in the brush border of the new-born pig colon and that this carrier is lost or modified during early post-natal development.     

Contamination from 131I, 103Ru, and 239Np in the eluate of 99Mo-99mTc generators loaded with (n, gamma)-produced 99Mo

Iodine-131, ruthenium-103, and neptunium-239 are present as contaminants in the eluate of 99Mo-99mTc generators loaded with 99Mo prepared by thermal-neutron irradiation of enriched 98Mo. The elution pattern of each of these contaminants is determined, together with the amounts found in the eluate of all generators tested over a 7-month period.     

Hypertrophic osteopathy and dysgerminoma in a mare

A case of hypertrophic osteopathy is described in a mare with a vague history of abdominal discomfort over the preceding 12 months. Bony swellings were obvious in the pastern area of both forelegs. There was a dysgerminoma of the left ovary that had metastasised to several abdominal lymph nodes and had infiltrated the posterior vena cava. There was no gross thoracic involvement although there was histologic evidence of tumour metastasis in pulmonary arterioles.