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Biomedical subjects

B O Spurlock

Publications and source records attributed to B O Spurlock.

13 recordsLinked to original sources
PubMed1989

Scanning electron microscopy of dysplastic Barrett's epithelium.

Twenty-six patients with Barrett's esophagus (BE) were followed prospectively by endoscopic examination and biopsy. Two biopsies were taken from each of 4 areas of BE. One was processed for light microscopy (LM) and one for scanning electron microscopy (SEM). Those in whom dysplastic BE was demonstrated by LM were reexamined at 6-mo intervals, and the others at yearly intervals. One patient had low grade dysplasia (LGD) by LM on entry, and in 2 others, LGD was recognized on the second examination. These changes have persisted in semiannual examinations over 3, 2, and 2 yr, respectively. SEM prints were examined without knowledge of LM findings, and features that might correlate with LGD by LM were sought. SEM findings were similar to those of Zwas et al. (Gastroenterology 90:1932, 1986) in that most glandular cells had surface features unlike either gastric or intestinal cells but unique to BE. In the patient with LGD on entry, there was an aggregate of very large cells covered by short microvilli with bald patches. In the other patients with LGD, there was more variation in size and shape of cells than in nondysplastic cases.

Adult↗
PubMed1989

The vacuolated glycogen-laden leukemic lymphocytes of a T-cell lymphoproliferative disorder.

In this report, we present a case of peripheral T-cell leukemia/lymphoma having mostly small- to medium-sized cells with abundant clear cytoplasmic vacuoles. The presentation at the time of diagnosis was one of leukemia/lymphoma. The phenotype of the leukemic cells of the peripheral blood was T1+, T11+, TQ1+, interleukin-2+, T3-, T4-, and T8-. The cells in the peripheral blood as well as those obtained from lymph node biopsy were strongly periodic acid-Schiff positive; the positivity was diastase sensitive. Electron microscopy confirmed the presence of glycogen in the cytoplasmic vacuoles. Serologic tests were negative for human T-cell lymphotropic virus type 1 antibody. The data presented in this article support the existence of a vacuolated variant of peripheral T-cell leukemia/lymphoma and further expand the morphological spectrum of T-cell lymphoproliferative disorders.

Aged↗
PubMed1988

Early effects of ionizing radiation on pulmonary endothelial angiotensin-converting enzyme and 5'-nucleotidase, in vivo.

We investigated the early phase of pulmonary endothelial injury in rabbits exposed to a single dose (30 Gy) of ionizing radiation to the chest, by measuring endothelium-bound ectoenzyme activities. Utilizing multiple indicator-dilution techniques, the metabolism of [3H]benzoyl-Phe-Ala-Pro (BPAP) and [14C]5'-AMP by angiotensin-converting enzyme (ACE) and 5'-nucleotidase (NCT), respectively, was studied during a single transpulmonary passage in conscious, chronically catheterized rabbits. From these data, the apparent kinetic constants Km and Amax were calculated. A significant (p less than 0.05) decrease in the metabolism of trace amounts of BPAP and 5'-AMP was observed at 2, 24, and 48 hr after irradiation. A similar decrease in the apparent first order rate constant (Amax/Km) of ACE was observed at 2 hr, but returned to control levels by 24 and 48 hr after irradiation. Apparent Km values of ACE for BPAP and NCT for 5'-AMP were elevated at 2, 24, and 48 hr post-treatment, whereas Amax (product of enzyme mass and the constant of product formation, kcat) of ACE was elevated at 2 and 24 hr but not at 48 hr, and Amax for NCT was elevated at 2 hr post-treatment only. Significant decreases in mean arterial blood pressure and pulmonary blood flow (Qb) at 2 hr post-treatment, and increases in Qb at 24 and 48 hr post-treatment were also recorded. No changes in endothelial structure were observed 2 hr after irradiation at the light or electron microscope level. We conclude that the early phase of radiation-induced lung injury includes changes in endothelial enzyme function in the absence of structural damage, as reflected in an apparent decrease in affinity of ACE and NCT for their substrates, allowing for the possibility that hemodynamic disturbances or their sequalae could also have contributed to the decrease in enzyme function.

5'-Nucleotidase↗
PubMed1987

Adherent platelets and surface microthrombi of the human aorta and left coronary artery: a scanning electron microscopy feasibility study.

As part of a feasibility phase of an investigator-initiated multicenter NIH supported study on the Pathobiological Determinants of Atherosclerosis in Youth (PDAY), we report observations on microthrombi and adherent platelets on the intima of the aorta and left anterior descending coronary artery. The long-term objective of this cooperative study is to define more precisely the pathogenesis of atherosclerosis during late childhood and early adulthood and to investigate the influence of selected risk factors known to be associated with clinically manifest disease in later life. Scanning electron microscopy (SEM) was utilized to survey broad areas of arterial intima. Of 109 specimens studied from 52 cases, microthrombi composed of a mixture of aggregated platelets and fibrin and measuring approximately 30-70 micron in size were observed in about 4% [corrected] of the specimens and in about 6% of the cases, while individually adherent platelets were observed in approximately 7% of the specimens and about 10% of the cases. Microthrombi and adherent platelets may be important in atherogenesis by stimulating proliferation of intimal smooth muscle cells through the release of a growth factor from platelets. This feasibility study has shown that SEM is a rapid and effective method for surveying large areas of arterial intima for the study of adherent platelets and microthrombi.

Adolescent↗
PubMed1982

Unusual cytoplasmic inclusion bodies in medullary carcinoma of the thyroid gland.

Medullary carcinoma of the thyroid from a 43-year-old patient showed 4 types of unusual cytoplasmic inclusion bodies ultrastructurally. Type 1 inclusion is composed of rod and doughnut-shaped bodies aggregated in the cytoplasma and not enclosed by a limiting membrane. Typical neurosecretory granules are intermingled with the rod and doughnut-shaped bodies. The doughnut-shaped bodies often have an electron dense core which is similar to the neurosecretory granules. The rod-shaped bodies are bounded by trilaminar unit membrane and have a slightly electron dense matrix. A centriole is often found associated with this type of inclusion. Type 2 inclusion is composed of small secretory granules and clear vesicles. These inclusions can be found either with or without surrounding membrane. Type 3 inclusion is a large osmiophilic body, or secondary lysosome, in which some degenerated organelles are discernible. Type 4 inclusion is a fragmented nucleus with condensation and margination of the chromatin, so-called karyorrhexis. Routine hematoxylin and eosin sections did not show each type of inclusion but semithin sections stained with Paragon suggested 4 different types of inclusions. Type 3 and 4 inclusions represent forms of degeneration and cell death in the tumor cells and probably represent a remote effect of radiation. Type 1 inclusion is not commonly associated with cell death and may represent a unique organellar aberration in these tumor cells. Type 2 inclusion is simply an aggregation of secretory granules and clear vesicles.

Adult↗
PubMed1981

Angiolymphoid hyperplasia with eosinophilia: report of a case with penile lesions.

A case of angiolymphoid hyperplasia with eosinophilia of the penis is reported. In addition to the proliferation of swollen endothelial cells with features of histiocytes ("histiocytoid endothelial cells"), the lesions also showed a remarkable proliferation of pericytes both in relation to formed vascular channels and away from them. The authors consider that the inflammatory component is associated with even the earliest stages in the development of the lesions and that it not be dismissed as secondary.

Adult↗
PubMed1981

A scanning and transmission electron microscopic study on an unusual pelvic tumor a case report.

A portion of a pelvic mass removed from a 38-year-old female, read out on frozen section as a papillary carcinoma with psammoma bodies, was submitted to the EM lab for routine processing. Transmission electron microscopy reveals the tumor mass to be composed of cuboidal and columnar epithelial cells with short apical microvilli and numerous sites of cellular attachments. That portion of the tumor processed for scanning electron microscopy, showed cells similar to those described above but an additional cell line containing numerous cilia were found scattered randomly throughout the entire sample. This finding prompted additional study of the original light and transmission samples to determine the nature of this neoplasm. Gross, microscopic, transmission and scanning micrographs will be presented to illustrate the merits of using multiple microscopic capabilities in the differential diagnosis of unusual tumors.

Adult↗
PubMed1975

A fine structure study of the anthocodium in Renilla mülleri. Evidence for the existence of a bioluminescent organelle, the luminelle.

A fine structure study of the anthocodium of the sea pansy, Renilla mülleri, was undertaken. The anthocodium, a known site of bioluminescence, was selected in order to determine whether a structural entity could be found which would satisfy the biochemical and physiological features associated with the known sites of bioluminescence in this animal. These sites, termed lumisomes, have previously been shown to be small (0.1-0.2 mum), membrane-enclosed vesicles which contain all the proteins necessary for bioluminescence and its immediate control. One of the lumisomal proteins is an intensely green fluorescent protein and has been used as a probe for the detection of the cellular sites of bioluminescence. This green fluorescence was associated only with gastrodermal cells. We report the identification of a unique morphological entity, restricted to the cells of the gastrodermis, which satisfies the biochemical and physiological requirements for bioluminescence in Renilla. It is a large (4-6 mum), membrane-bounded subcellular organelle comparable in size to a subcellular structure whose green fluorescence is typically associated with the in vivo bioluminescence. Furthermore, it is filled with smaller membrane-bounded vesicles which have the same size and shape as the lumisomes. We suggest that the organelle identified in this study be termed a luminelle.

Cnidaria↗
PubMed1975

Transmission electron microscopy of tissue prepared for scanning electron microscopy by ethanol-cryofracturing.

Tissue processed for scanning electron microscopy by ethanol-cryofracturing combined with critical point drying was embedded and sectioned for transmission electron microscopy. Study of specimens cut in a plane passing through the fracture edge indicated that preservation of cellular fine structure of fractured cells was excellent. Even at the most peripheral edge of the fracture there was no evidence that movement of cytoplasmic components occurred to distort the original structural organization of fractured cells. Lack of cytoplasmic detail in ethanol-cryofractographs has been due more to the nature of the fracturing of the tissue and to the obscuring effects of the metal coating than to structural deformation at the fracture edge or to limitations in resolving power of the scanning electron microscope used.

Animals↗
PubMed1974

Electron microscopy of young Candida albicans chlamydospores.

One- to three-day-old cultures of Candida albicans bearing chlamydospores were grown and harvested by a special technique, free of agar, and prepared for ultramicrotomy and electron microscopy. These young chlamydospores exhibited a subcellular structure similar to that of the yeast phase, e.g., cytoplasmic membrane, ribosomes, and mitochondria. Other structural characteristics unique to chlamydospores were a very thick, layered cell wall, the outer layer of which was continuous with the outer layer of the suspensor cell wall and was covered by hair-like projections; membrane bound organelles; and large lipoid inclusions. Only young chlamydospores less than 3 to 4 days old exhibited these ultrastructural characteristics.

Candida albicans↗