Richard B. Wilson

Modified thiocarbohydrazide procedure for scanning electron microscopy: routine use for normal, pathological, or experimental tissues.

A modified thiocarbohydrazide (TCH) technique to cross-link osmium layers has resulted in a reliable method for preparing a wide variety of soft biological tissues for scanning electron microscopy without the use of evaported metal. The technique works equally well on tissues with smooth surfaces and those with abrupt changes in contour or cut surfaces, as in biopsy or autopsied material or pathologically altered tissues, and thus has wide applicability. Small surface structures and junctional areas between cells are distinct. In addition, thin cells such as alveolar endothelium in the lung exhibit a transparent property, allowing the visualization of cells within the capillary lumen while retaining adequate contrast for study of the capillary wall itself. Absence of an evaporated metal coat makes the removal of tissue from the scanning electron microscope specimen easy for embedding and examination of the same material with the transmission electron microscope.

CW electrooptical properties of InGaAsP(λ = 1.3 µm) buried-heterostructure lasers

The fabrication procedure, electrical properties, optical-bean characteristics, spectral characteristics, and temperature dependence of emission wavelength and threshold of InGaAsP buried-heterostructure (BH) lasers emitting at 1.3 μm are described. The dimensional requirements for fundamental-transverse mode operation have been determined. BH devices are characterized by low threshold currents, fundamental transverse mode operation, linear light output, and narrow spectral width. For 380 μm long devices threshold currents of 40 mA, slope efficiencies of 18 percent, forward resistance of 5 Ω, and T 0 values of 75 K have been attained.

The pathogenesis of hemorrhage in the lung of the hamster during acute leptospirosis

The pathogenesis of lung hemorrhage in hamsters was studied during the early stage of leptospirosis. Hemorrhage was seen in all hamsters at 48 h when the count was only 2.3×104 leptospires/g of lung tissue. The lungs showed a much lower count/g of tissue than either the liver or blood throughout moat of the 96 h observation period. The formation of blebs characteristically caused by toxic substances was seen in the capillary endothelium and occasionally in the capillary epithelium. The low number of leptospires in the lungs as determined by culture, light and electron microscopy and the bleb formation of the lung capillaries support the concept that a toxic factor(s) is responsible for the hemorrhagic manifestations of leptospirosis.

Osteogenic and sarcomatoid differentiation of a renal cell carcinoma

Sarcomatoid renal cell carcinoma is an uncommon renal tumor, and osteogenic differentiation has been reported in only a few of these tumors. The authors report such a case with radiographic, light microscopic, and electron microscopic findings, which demonstrate that the sarcomatiod areas of the tumor are derived from the malignant epithelial cells, retaining epithelial features such as desmosomes and lumina with microvilli. The use of electron microscopy is important in the establishment of this diagnosis.

Central Nervous System Involvement in Congenital Visceral Fibromatosis

Congenital visceral myofibromatosis is an uncommon disorder characterized by multiple tumors of myofibroblastic origin in the neonatal period. The natural history of the disorder has been well delineated. The myofibroblast is the cell of origin of the tumor. This is a report of a patient in whom multiple mesenchymal tumors occurred in the CNS as well as in other organs. Light and electron microscopic findings of the CNS lesions are similar to those of the somites and viscera.

Nephropathy-Gonadal Dysgenesis, Type 2: Renal Failure in Three Siblings With XY Dysgenesis in One

The nephropathy-XY gonadal dysgenesis syndrome in a 17-year-old phenotypical female with focal glomerulosclerosis was associated with renal failure in two sisters, one with crescentic glomerulonephritis at 27 months, and one with membranoproliferative glomerulonephritis at 10 years. Neither the propositus or the siblings had the distinctive mesangial sclerosis of nephropathy-XY dysgenesis, type 1 (Drash syndrome). The association of nephropathy-XY dysgenesis with familial nephritis of heterogeneous pathology suggests that nephropathy-XY dysgenesis, type 2, may relate to separate genetic loci for XY dysgenesis and glomerulopathy or reflect a loss of protection against familial renal disease when the Y chromosome is absent or defective.

Monolithic integration of InGaAsP heterostructure lasers and electrooptical devices

Monolithically integrated InGaAsP heterostructure lasers (\lambda = 1.3 \mum) coupled to low-loss InGaAsP waveguides are described. The integrated InGaAsP etched-mirror lasers are fabricated using liquid-phase epitaxy and a new material-selective chemical etching technique. The integrated devices have been operated as optically coupled lasers, photodiodes, and resonant optical amplifiers. For lasers with two etched mirrors, differential transfer efficiencies as high as 8 percent have been measured for waveguide-coupled laser-photodiode pairs. The waveguide-coupled InGaAsP lasers with12.5 \times 300 \mum contact stripes and two etched mirrors have room-temperature threshold currents as low as 580 mA pulsed. Similarly fabricated etched-mirror lasers without the waveguide layer have threshold currents as low as 280 mA pulsed (25 μm stripewidth). In order to obtain lower threshold currents and stable transverse-mode characteristics, InGaAsP buried-heterostructure (BH) lasers with chemically etched mirrors have been fabricated. The etched-mirror BH lasers have threshold currents as low as 160 mA pulsed. Evaluation of the etched-mirror reflectivity for the material-selective-etched lasers yielded an estimated reflectivityR = 0.01-0.03and scattering lossS = 0.6-0.8. Similar evaluation of a BH laser with non-material-selective-etched mirrors gave an estimated reflectivityR = 0.11and scattering lossS = 0.4. Analysis of the mode reflectivity of nonideal double-heterostructure laser mirrors shows that the reflectivity is limited by misalignment (tilt) of the etched mirrors.

Structure of the pancreas in Syrian hamsters

The Syrian hamster is a suitable animal model for the study of pancreatic neoplasms of ductal origin. Therefore, the present study was performed to obtain basic information on the pancreas of this spe

Isolation of a New, Pink, Obligately Thermophilic, Gram- Negative Bacterium (K-2 Isolate)

A pink, obligately themophilic (60 C), gram-negative, nonmotile, nonsporeforming, rod-shaped bacterium with a deoxyribonucleic acid base ratio of 64 to 65 mol% guanine plus cytosine has been repeatedly isolated from slightly alkaline, man-made and natural thermal aquatic environments. This bacterium (K-2 isolate) does not appear to have been described previously and it has been deposited with the American Type Culture Collection as an unidentified bacterium with the accession no. 27599.

Isolated granulomatous gastritis: treatment with corticosteroids

Granulomatous disease of the stomach is a rare disorder with multiple causes. We successfully treated a patient who had granulomatous disease that was confined to the gastric antrum with corticosteroids. We believe this is the first such report.