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Biomedical subjects

J L Griffin

Publications and source records attributed to J L Griffin.

At least 19 recordsLinked to original sources
PubMed1991

Flow cytometry of fine needle aspirations of the Sprague-Dawley rat testis: defining normal maturation and the effects of multiple biopsies.

Quantitative assessment of spermatogenesis by flow cytometry reproducibly correlates with histological examination. Flow cytometry of fine needle aspirates from the testis was used to analyze normal spermatogenesis of Sprague-Dawley rats. Aged matched male weanlings were divided into 3 groups: group 1-5 rats underwent bilateral percutaneous aspiration of the testes with a 22 gauge Chiba needle on postpartum days 19, 24, 30 and 40; group 2-5 rats aspirated on days 24, 30 and 40, and group 3-4 rats aspirated on days 30 and 40. This sequential approach allowed for evaluation of normal spermatogenesis and the effects of repeated fine needle aspiration on spermatogenesis. Deoxyribonucleic acid distribution analysis by flow cytometry correlates with haploid (1N), diploid (2N), tetraploid (4N) and S phase cell populations. These cell populations were evaluated and comparisons among each group were made at all biopsy times. No significant differences in mean 2N, 4N or S phase cell populations in single versus repeat biopsied testes were detected. However, there was a significant increase in the 1N population at 30 days post partum in the repeat biopsy group (p = 0.037), which normalized by day 40. This increase in 1N corresponds to the beginning of meiosis, which is maximal between postpartum days 30 and 40, and occurs earlier in the repeat biopsied testis. Repeat fine needle aspiration of the testis can be performed without significantly affecting spermatogenesis in the "weanling" rat. This provides a useful technique in the future investigations of the time related effects of varicocele, chemotherapy and toxicologic drugs on spermatogenesis.

Animals↗
PubMed1990

Mitochondrial myopathy caused by long-term zidovudine therapy.

Both infection with the human immunodeficiency virus type 1 (HIV) and zidovudine (formerly called azidothymidine [AZT]) cause myopathy. To identify criteria for distinguishing zidovudine-induced myopathy from that caused by primary HIV infection, we reviewed the histochemical, immunocytochemical, and electron-microscopical features of muscle-biopsy specimens from 20 HIV-positive patients with myopathy (15 of whom had been treated with zidovudine) and compared the findings with the patients' clinical course and response to various therapies. Among the zidovudine-treated patients, the myopathy responded to prednisone in four, to the discontinuation of zidovudine in eight, and to nonsteroidal anti-inflammatory drugs in two. Numerous "ragged-red" fibers, indicative of abnormal mitochondria with paracrystalline inclusions, were found in the biopsy specimens from the zidovudine-treated patients but not in those from the other patients. The number of these fibers appeared to correlate with the severity of the myopathy. All the patients, regardless of whether they had been treated with zidovudine, had inflammatory myopathy characterized by degenerating fibers, cytoplasmic bodies, and endomysial infiltrates consisting of CD8+ cells (mean +/- SD, 60.7 +/- 6.4 percent) and macrophages (39.2 +/- 6.4 percent) associated with Class I major histocompatibility complex (MHC-I) antigens (HLA-A, -B, and -C antigens) in the muscle fibers. The numbers and percentages of CD8+ cells and macrophages were similar in both the zidovudine-treated and the untreated HIV-positive patients. Specimens obtained on repeat muscle biopsy from two patients in whom the myopathy responded to the discontinuation of zidovudine showed remarkable histologic improvement. We conclude that long-term therapy with zidovudine can cause a toxic mitochondrial myopathy, which coexists with a T-cell-mediated inflammatory myopathy that is restricted to MHC-I antigen, and is indistinguishable from the myopathy associated with primary HIV infection or polymyositis in HIV-seronegative patients.

AIDS-Related Complex↗
PubMed1990

Bubble-induced dysfunction in acute spinal cord decompression sickness.

Five anesthetized dogs undertook a chamber dive, on air, to 300 feet of seawater for 15 min. After the dive, spinal cord decompression sickness was detected by recording a reduced amplitude of the somatosensory evoked potential compared with predive base-line values. After the diagnosis of decompression sickness and rapid perfusion fixation of the animal, the spinal cord was removed and examined histologically. Numerous space-occupying lesions (SOL) that disrupted the tissue architecture were found in each cord, mainly in the white matter. The size and distribution of the SOL were determined using computerized morphometry. Although SOL occupied less than 0.5% of the white matter volume, we tested a number of algorithms to assess whether the SOL may have been directly involved in the loss of spinal cord function that followed the dive. We determined that the loss of somatosensory evoked potential amplitude may be attributed to the SOL if 30-100% of the spinal cord fibers that they displaced were rendered nonconducting. A number of possible mechanisms by which SOL may interfere with spinal nerve conduction are discussed.

Animals↗
PubMed1988

Myosin ATPase intermediate density fibers for diagnosis of reinnervation.

Myosin ATPase (pH 9.4) differentiates two muscle fiber types in healthy human muscle, while diseased muscle often contains intermediate density fibers (IDFs). We evaluated the possibility that, since almost all IDFs in pathologic muscle biopsies are changing type after reinnervation by a motor axon of the opposite type, IDFs are useful in diagnosis. In a retrospective study of 208 muscle biopsies, IDFs were seen as often as were esterase-positive angular atrophic fibers (EPAAFs). In denervation identified by EMG and by histopathology, EPAAFs and IDFs were found much more often than were other indicators. Of biopsies diagnosed without use of IDFs as minimal histologic change or no pathologic diagnosis, 16% had IDFs with sparse EPAAFs and 21% had IDFs without EPAAFs, suggesting mild denervation with rapid reinnervation. IDFs correlate well with EPAAFs, identifying reinnervated versus denervated fibers. Type grouping reveals completed reinnervation change that may be many years old, while IDFs are changing type when biopsied and thus reveal recent reinnervation and preceding denervation. IDFs usefully belong with the histochemical indicators used to evaluate muscle disease.

Biopsy↗
PubMed1988

Fine structure and taxonomic position of the giant amoeboid flagellate Pelomyxa palustris.

Specimens of Pelomyxa palustris from five collecting sites had numerous nonmotile flagella. The structures are called flagella because of morphological similarities to flagella and because P. palustris has affinities with amoeboid flagellates. Flagella were photographed on living cells and studied by transmission and scanning electron microscopy. From 64 to 742 flagella per cell were estimated from scanning electron microscopy of ten cells 204 to 1269 micron in length. The nonmotile flagella arise from basal granules which were, in one strain, surrounded by radiating electron-dense microtubules. This strain also had excess axonemal microtubules. Abundant cytoplasmic microtubules were arranged in several different patterns. In about half of the P. palustris cells in which nuclei were studied, microtubules were either apposed to the nuclear membrane in a parallel alignment (with some also radiating) or radiating from the nuclear membrane (with none parallel). Bacteria associated with nuclei were of three characteristic types: Gram-negative rods, Gram-positive rods, and large rods. All nuclei within a given trophozoite had similar perinuclear features. Recent proposals for separation of Pelomyxa to its own phylum (based on its proposed primitive, unique nature) can not be justified. Pelomyxa is a complex, highly specialized organism adapted to live in a specific fresh-water environment. Mastigamoebid amoeboid flagellates of the genera Mastigamoeba, Mastigella, Mastigina, and possibly Dinamoeba are placed with Pelomyxa within the order Pelobiontida Page, 1976, emend., containing two families. Pelomyxidae Schulze, 1877, and Mastigamoebidae Goldschmidt, 1907.

Amoeba↗
PubMed1978

Myoadenylate deaminase deficiency: a new disease of muscle.

Five cases of a new disease presented with muscular weakness or cramping after exercise; three of the cases also had an elevated serum creatine phosphokinase. Muscle biopsies were histologically normal but lacked adenylate deaminase by stain and solution assay, while the erythrocyte isozyme was normal. A clinical diagnostic test has been developed, and the human enzyme was separated by acrylamide-gel electrophoresis.

AMP Deaminase↗
PubMed1977

Electron microscopy of negatively stained jackbean urease at three levels of quaternary structure, and comparison with hydrodynamic studies.

Electron microscopy, with sodium phosphotungstate as negative stain, has been carried out on purified jackbean urease prepared at three levels of quaternary structure: (a) A1 urease, Mr = 240 000, S20,W = 11.5 S (b) alpha urease, Mr = 480 000, S20,w = 18.3 S (c) polymers of alpha urease above the tetramer stage. The compatibility of the images from level to level leaves no doubt that the enzyme itself is being visualized, and the following geometry is suggested by electron microscopy: A1 molecules are cyclic trimers, which pair up in eclipsed position across a 1-nm cleft to form the hexameric alpha, which displays D3 (or 32) symmetry of a trigonal prism. Polymers consist of alpha molecules aligned with their clefts coplanar and an angle of 120 degrees between each triplet of 3-fold axes. These features correspond reasonably well with sedimentation and electrophoretic studies of the solvated enzyme, which have indicated a hemispherical A1, a spherical alpha, and string-of-beads polymers. Sedimentation constants of the urease polymers up through the pentamer level were found to be compatible with the rosette, straight-chain, and zig-zag forms seen in the electron microscope, and with the suggested protomer arrangement in A1 and alpha urease.

Macromolecular Substances↗
PubMed1977

Orientation of Euglena gracilis by electromagnetic fields: theory and experiment.

Computer data derived from theoretical treatments of the orientation of ellipsoidal particles in alternating fields is compared with experimental data from microscopic studies on Euglena gracilis, and elongated free-living flagellate. Computed data based upon a theoretical treatment by SAITO, SCHWAN and SCHWARZ showed good agreement with experimental results, predicting the relationship between cellular orientation, the frequency of the impressed field, and the conductivity of the suspending medium.

Computers↗
PubMed1975

Utility of the Mini-Mult with parents of emotionally disturbed children.

In order to determine the potential usefulness of the Mini-Mult as a screening instrument with parents of emotionally disturbed children, two studies were conducted. In the first study 128 MMPI profiles were rescored for the Mini-Mult and comparisons with MMPI were made. In the second study 50 parents were administered both the MMPI and the Mini-Mult. Results of both studies indicate that the Mini-Mult is not a good screening instrument with parents of emotionally disturbed children.

Adult↗
PubMed1975

The Mini-Mult with criminal psychiatric patients.

In order to determine the usefulness of the Mini-Mult with criminal psychiatric patients, 107 MMPI profiles were rescored for the Mini-Mult and compared with the standard MMPI. Correlations between the two test forms were high but eight of the eleven means of the scales on the Mini-Mult were significantly different from the MMPI. A modest correspondence between indexes of psychopathology and scale peaks was found. Results were interpreted as indicating that the use of the Mini-Mult is not justified with this population.

Adult↗