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The distribution of Merkel cells in human fetal hair follicles was studied using whole mounts of separated epidermis with attached hair follicles. The technique had the advantage of enabling the elucidation of the spatial relationships of Merkel cells with other cells in the skin. In a 16-week-old fetus the hair anlagen had formed one or two epithelial swellings of variable size. In a 17-week-old fetus sebaceous glands and the bulge of the hair follicle were recognizable and immunoreactive Merkel cells were present in the bulge and surrounding the acrotrichium (intraepidermal follicular canal). In a 20-week-old fetus the sebaceous gland and bulge were well formed and immunoreactive Merkel cells were concentrated in the bulge and infundibulum. In vertical sections of a 20-week-old fetus immunoreactive Merkel cells were also situated in the vicinity of the bulge. Arrector pili muscles were first observable in a 24-week-old fetus being weakly stained with anti-desmin antibody. In a 24-week-old fetus, nerves were also stained within the arrector pili muscles with S-100 protein antibody. In the presumptive arrector pili muscle immunoreactivity for S-100 protein developed before or at the same time as immunoreactivity for desmin. Merkel cells or their products in the bulge may serve as attractants for the growing arrector pili muscle which contain peripheral nerves. Following our report that dermal Merkel cells influence the formation of the dermal nerve plexus, perifollicular Merkel cells near the bulge may also play an inductive and growth-stimulative role for the perifollicular nerve plexus.

Abstract Somatic embryogenesis was induced in callus tissues derived from young flower buds of Panax notoginseng via callus within 18 weeks of culture. The mature somatic embryos were germinated on half-strength Murashige and Skoog's (MS) medium supplemented with gibberellic acid A₃(GA) and 6-benzyladenine (BA). The most suitable medium for optimal root formation proved to be MS medium supplemented with 1-naphthaleneacetic acid (NAA). Total DNA was extracted from the leaves of the regenerated plantlets of P. notoginseng. Analysis of random-amplified polymorphic DNA (RAPD) using 21 arbitrary oligonucleotide 10-mers, showed the genetic homogeneity of P. notoginseng. The amplification products were monomorphic for all of the plantlets of P. notoginseng regenerated by embryogenesis, suggesting that somatic embryogenesis can be used for clonal micropropagation of this plant.

We have quantitated a specific apoprotein of rat pulmonary surfactant using an electroimmunoassay and have examined its content in the lungs of alloxan-induced diabetic rats. Rat lung surfactant was purified and was used to raise antisera in rabbits. Antibodies against rat serum proteins were removed from the IgG fraction of the antiserum by means of affinity chromatography using rat serum-linked to Sepharose 4B. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of rat surfactant revealed the presence of one major protein, a molecular weight of about 16,000 dalton, and this protein was a non-serum protein and specific to the lung by immunological tests. It seems likely that the 16,000 dalton protein obtained in the present study is similar to the 11,000 dalton or to a fragment of the 34,000 dalton protein, reported by other investigators. Using the monospecific antiserum against this protein of rat surfactant, the apoprotein content of pulmonary surfactant in alloxan-induced diabetic rats was measured by means of rocket electroimmunoassay. The lungs of diabetic rats contained less of this apoprotein than the lungs of control rats. This finding suggests that diabetes mellitus may induce a disturbance of protein metabolism in the lungs, as well as of carbohydrates and phospholipids, which may cause pulmonary dysfunction in diabetic patients observed in our previous studies.

A laser-induced thermochemical reaction has been used to etch single crystalline magnetic ferrite for industrial application to recording-head processing. Scanning focused Ar-ion laser irradiation to ferrite in flowing aqueous solutions of KOH or H3PO4 resulted in etch rates of 350–400 µm/s with aspect ratios of up to 40. Metal-In-Gap (MIG) head structures with Sendust (FeAlSi) have been successfully fabricated using laser chemical processing. The MIG head fabricated by laser chemical processing showed better performance than that by conventional mechanical machining.

Prednisolone, a water-soluble glucocorticoid hormone, suppressed the secretion of interleukin-1 beta from human peripheral blood mononuclear cells in culture. The prednisolone-induced suppression of the monokine release was doserelated and the half maximal response was observed at 0.1 nM.