Human genital melanocytes as androgen target cells.

As some parts of human skin - such as genital and areolar skin - become pigmented after puberty, melanocytes in these regions are thought to be sex hormone target cells. We immunohistochemically localized androgen receptors in the nuclei of cultured human genital melanocytes by monoclonal and polyclonal antibodies. When these cells were incubated with [1,2-3H]-testosterone, the major metabolite in the medium was dihydrotestosterone and 5alpha-reduction predominated over 17beta-oxidation. Androgen receptor and type I 5alpha-reductase mRNAs could be detected in genital melanocytes by reverse transcriptase polymerase chain reaction. The tyrosinase activity was stimulated by the addition of androgen. This stimulation was antagonized by cyproterone acetate, whereas tyrosinase mRNA expression was not affected by androgen. These results indicate that human genital melanocytes are androgen target cells, and that androgen plays a role for pigmentation in the specific regional skin after puberty.

Growth stimulation of normal melanocytes and nevocellular nevus cells by gastrin releasing peptide (GRP).

In order to know the possible effects of gastrin releasing peptide (GRP) on nevus cells and melanocytes, we studied the effect of GRP on the proliferation of cultured human nevus cells and normal melanocytes. MTS assay showed that GRP stimulated the growth of viable melanocytes at 1000 ng/ml. GRP also stimulated the growth of nevus cells in a dose dependent manner and maximum stimulation was obtained at 100 ng/ml of GRP. GRP was less effective for growth stimulation of normal melanocytes than nevus cells. The cytoplasm of nevus cells were positively stained by polyclonal anti-GRP antibody. We also detected the expression of GRP and GRP receptor mRNAs in these cells by RT-PCR. These results suggest that GRP acts as an autocrine growth factor for nevus cells and normal melanocytes.

Minoxidil increases 17 beta-hydroxysteroid dehydrogenase and 5 alpha-reductase activity of cultured human dermal papilla cells from balding scalp.

Minoxidil is known to induce hair growth in male pattern baldness, for which development androgen plays a central role. We studied the effect of minoxidil on testosterone metabolism by cultured dermal papilla cells from balding or nonbalding scalp and dermal fibroblasts. In all three groups, 17beta-hydroxysteroid dehydrogenase activity was much higher than 5alpha-reductase activity. Minoxidil increased 17beta-hydroxysteroid dehydrogenase activity by nearly 40% (P < 0.001) in dermal papilla cells of balding scalp, whereas the effect was less marked in dermal papilla cells from nonbalding scalp and dermal fibroblasts. 5alpha-Reductase activity was also slightly increased by minoxidil in dermal papilla cells from balding scalp. Again, the effect on 5alpha-reductase activity was insignificant in the other two groups of cells. Whether such modification of testosterone metabolism in dermal papilla cells of balding scalp by minoxidil is related to its therapeutic effect remains unknown.

A repeat-batch membrane bioreactor with a phase inversion for the desaturation of isopropyl palmitate by a mutant Rhodococcus strain.

A repeat-batch membrane bioreactor was constructed for the novel bioconversion of isopropyl hexadecanoate to isopropyl cis-6-hexadecenoate by a Rhodococcus mutant. The addition of glutamate, thiamine, and MgSO(4) was very effective in improving not only the rate and yield of the bioconversion but also the maintenance of desaturation activity during cell recycling. An oil-in-water (O/W) type emulsion of the reaction medium was inverted to a water-in-oil (W/O) type by discharging the water phase from the reaction mixture. The continuous oil phase containing the product could effectively be recovered through a hydrophobic hollow-fiber module. By decreasing the oil-to-water ratio upon addition of fresh medium, the medium was spontaneously inverted again to an O/W type emulsion to proceed with the next conversion. The batch reaction coupled with the phase inversion could be repeated more than 13 times for over about 300 h operation. Finally, a highly purified product was obtained with high yield by the urea adduct procedure.

Valve replacement of childhood: follow-up results and complications.

This study concerned 18 cases of value replacement in patients than 15 years, between 1964 and 1980. In this period, there was a total of 30 such cases, but there were eight hospital deaths and four cases with less than two years postoperative observation. These 12 cases were excluded from the study. The average follow-up period of the 18 cases was eight years and nine months. During this period, six cases were associated with postoperative complications, which consisted of three cerebral emboli, two malfunctions of the implanted prostheses and one congestive heart failure. Three cases involved prosthesis-related death. Secondary implantations were performed in two cases; one for relative stenosis of the prosthesis and the other for calcification of the porcine xenograft. Physical activity in the 15 survivors has been excellent in all but two cases with arrhythmia and sequelae of cerebral damage due to surgery.

Double involvement of extramammary Paget's disease in the genitalia and axilla.

We here reported a case of an 82-year-old man with double involvement of extramammary Paget's disease in the genitalia and axilla. Physical examination revealed erythema and reddish tumors on the pubic area and scrotum and irregular-shaped erythema on the left axilla. The skin biopsy sample from the genital area showed Paget's cells in the epidermis and upper dermis. The specimen from the left axilla showed Paget's cells scattered in the epidermis but not in the dermis.

Histochemical observation and cellular distribution of ascorbic acid in persimmon leaves.

This study was carried out to resolve the discrepancy of data for the proportion of ascorbic acid and dehydroascorbic acid in persimmon leaves at the final stage of the season and to clarify their cellular distributions using histochemical and biochemical techniques. Fresh persimmon leaves were collected and used on July 31, September 5 and October 7, 1996. Ascorbic acid and dehydroascorbic acid in subcellular fractions were determined by the HPLC method that was found to be the most reliable for separation. The percent of dehydroascorbic acid in the total leaves was found to be almost constant (between 32 and 37%) in all preparations tested. In all preparations, more than 90% of the ascorbic acid and dehydroascorbic acid was found in the soluble fraction. The histochemical detection of ascorbic acid and an electron micrograph of persimmon leaf cells showed that the reactive color, after the reduction of silver nitrate under acidic conditions, in the leaves of all three preparations was mainly found on the face side of columned-type palisade parenchyma cells where chloroplasts were not rich and large vacuoles were seen. On the inner side of the palisade parenchyma cells where chloroplasts were the richest, only weak color development was observed. This study demonstrates that the percent of dehydroascorbic acid in persimmon leaves did not exceed 40% at least until October 7. It also shows that in persimmon leaf cells, ascorbic acid is mainly localized in the cytosol of palisade parenchyma tissue cells where large vacuoles are seen.

Effects of vitamin B12-deficiency on testes tissue in rats.

The state of vitamin B12-deficiency in rats was evaluated by determination of hepatic vitamin B12-dependent enzyme activities after the animals had fed on a vitamin B12-deficient soybean protein diet for 150 days. The effect of vitamin B12-deficiency on testicular tissue was also studied by morphological observations. Growth of vitamin B12-deficient rats was retarded and marked increase in urinary methylmalonic acid was observed. Vitamin B12 contents in the organs were depressed distinctly by the deficiency, especially in testes, vitamin B12 content decreased to 2.5 ng/g. Hepatic methionine synthase and methylmalonyl-CoA mutase activities showed striking depression to 5% of the control rats and extreme vitamin B12-deficiency was confirmed. Testes weight also showed marked decrease together with their relative weight per 100 g body weight. Morphological observations of testes of vitamin B12-deficient rats revealed atrophy of the seminiferous tubules and aplasia of sperms and spermatids. The above results proved that vitamin B12-deficiency affected rat testes, and suggested that the rat could be the animal model for elucidation of the mechanism of B12 action on testicular functions.

Effect of vitamin B12-deficiency on testicular tissue in rats fed by pair-feeding.

The effect of vitamin B12 (B12)-deficiency on testicular tissue was investigated through morphological observations of the rats which had been fed on a B12-deficient soybean protein diet by pair-feeding for 100 days. Testicular B12 content was depressed distinctly by the deficiency. Testes weight and their relative weight (weight per 100 g body weight) as well, decreased significantly as compared with those of pair-feeding control rats. Although the decrease in the testicular B12 content due to B12-deficiency was compensated by the administration of cyanocobalamin (CN-B12), alleviation of the decrease in testes weight and relative testes weight was not observed under the condition of the short-term CN-B12 administration. Morphological observations of the testicular tissue in B12-deficient rats revealed atrophy of the seminiferous tubules and aplasia of sperms and spermatids, while testicular findings in both ad libitum-feeding control rats and pair-feeding control rats were normal. There was a tendency for the decrease in seminiferous tubules showing spermatogenesis to be alleviated by administration of CN-B12. The above results indicate that the morphological changes in the testicular tissue are ascribable to B12-deficiency.

Vitamin B-12-deficiency affects immunoglobulin production and cytokine levels in mice.

To clarify the role of B-12 in the immunological function, serum C3, IgM, IgG, IgE contents, splenocytes expression of CD4, CD8, and CD4 positive intracellular IFN-gamma and IL-4 were examined in B-12-deficient mice, and the effect of the administration of CH3-B-12 was also studied. Serum C3, IgM and IgG contents were lower in B-12-deficient mice than in the control mice. On the other hand, serum IgE content was significantly higher in B-12-deficient mice, and the value in CH3-B-12 administered mice, administered CH3-B-12 to B-12-deficient mice for 48 h before the end of feeding period, showed a tendency to recovery. CD4+CD8- cells and CD4+CD8-/CD4-CD8+ ratio in splenocytes were significantly higher in B-12-deficient mice than in control mice. CD4+IFN-gamma+ cells was significantly lower in B-12-deficient mice than in control mice, and CD4+IL-4+ was significantly higher in B-12-deficient mice than in control mice. These results suggest that B-12-deficiency causes CD4+CD8-T cells shift from the T helper type 1 to the T helper type 2, which participate in the IgE production and elevates CD4+CD8-/CD4-CD8+ ratio. Thus, B-12 plays a role in maintaining the immune function in mice.

Changes in CD4+CD8-/CD4-CD8+ ratio and humoral immune functions in vitamin B12-deficient rats.

To clarify the role of vitamin B12 in the function of cell-mediated and humoral immune functions, the splenocytes expression of CD4, CD8 and serum C3, IgM, IgG concentrations were examined in vitamin B12-deficient rats, and the effect of the administration of methylcobalamin was also studied. The CD4+CD8-/CD4-CD8+ ratio in splenocytes was significantly higher in vitamin B12-deficient rats than in control rats (p < 0.05). The value in the 48 hours after methylcobalamin administration group, was within the normal range (p < 0.05). From these results, the elevation of the CD4+CD8-/CD4-CD8+ ratio by vitamin B12-deficiency was confirmed in rats. The serum C3, IgM and IgG concentrations were lower in the vitamin B12-deficient group than in the control group. These findings suggest that vitamin B12 plays a role in maintaining the immune function in rats.

Utilization of dietary protein in the vitamin B12-deficient rats.

Utilization of dietary protein in vitamin B12 (B12)-deficient rats was evaluated by determinating the content of plasma protein, urinary excretion of nitrogen compounds, and nitrogen-balance after the rats were fed on a B12-deficient soy bean protein diet by pair-feeding for 100 days. The severe B12-deficiency was confirmed in rats by a remarkable increase in urinary methylmalonic acid excretion and a remarkable decrease in the hepatic B12 level. Growth of B12-deficient rats was significantly retarded as compared both with ad libitum-feeding control rats and pair-feeding control rats. The growth retardation due to B12-deficiency was alleviated by the administration of 1 microgram/day of CN-B12 for 30 days. Plasma total protein and albumin levels in rats fed on a B12-deficient diet decreased, compared with those in pair-feeding control, and increase in urea-nitrogen was observed. The excretion of urinary nitrogen compounds, such as urea-nitrogen, allantoin, and creatinine, was significantly depressed by B12-deficiency compared with those in pair-feeding control. The administration of CN-B12 to B12-deficient rats for 30 days resulted in the recovery of the changes in plasma proteins and urinary excretion of nitrogen compounds. The above results suggested that the extreme B12-deficiency depressed the utilization of dietary protein in rats. Moreover, the decrease in urinary urea-nitrogen excretion was supposed to be due to the adaptation by the depression of the dietary protein utilization.

Serum C3 content in vitamin B(12)-deficient rats.

As a clue to clarifying the role of vitamin B12 (B12) in the function of the complement system, serum C3 content was determined in B12-deficient rats, and the effect of the administration of methylcobalamin (CH3-B12) on the serum C3 content was also studied. It was found that the serum C3 content in rats fed on a vitamin B12-deficient diet for 90 and 120 days significantly decreased compared with that in control rats. The administration of CH3-B12) restored the serum C3 content to control levels. The above results indicate that B12-deficiency depressed the serum C3 content and lowered humoral immunocompetence, and that these changes were ascribable to B12-deficiency.

Influence of CRT workstation on observer's performance.

The effects of the operability of the prototype CRT workstation and room illumination upon observer's performance were studied. In the experiment of reading CT images as a routine daily work at the CRT workstation, the average time required to analyse one CT image under a room illuminance of 100 lux was longer than that on the film viewbox. Prolongation occurred due mainly to the longer time required to retrieve and to arrange images as observers desired, and the limitation to the number of images simultaneously displayed on two CRT monitors. In the ROC studies to detect small pulmonary nodules on CRT images of computed radiography with imaging plate, illuminance around 170 lux showed the best result and a statistically significant difference (P less than 0.05) as compared with that of 480 lux. In addition to the radiologist's visual performance, room illumination must also be taken into consideration as it influences the observer's performance and diagnostic efficiency.

[Adenosquamous carcinoma originating from the thyroid gland--report of a case and review of the literature].

Adenosquamous cell carcinoma originating from the thyroid gland is extremely rare. Only a few cases have been reported by light-microscopic observations. Like pure squamous cell carcinoma of the thyroid gland, it is generally thought to originate from the thyroid follicular epithelium and to be concerned with squamous metaplasia of the follicular epithelium. In our case, papillary adenocarcinoma was found in the thyroid gland, with the transition to squamous cell carcinoma. Immunohistochemical study for thyroglobulin and keratin further implied he transition of adenosquamous cell carcinoma in the thyroid gland. The origins of squamous cells in thyroid carcinoma are briefly discussed.