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Biomedical subjects

R A Perry

Publications and source records attributed to R A Perry.

At least 55 records · Page 3Linked to original sources
PubMed1987

Entanglement of embolised thrombus with an endocardial lead causing pacemaker malfunction and subsequent pulmonary embolism.

A 67 year old woman with a permanent pacemaker was admitted with pulmonary oedema and mitral valve incompetence two months after a myocardial infarction. Echocardiograms showed good left ventricular function and a large coil of apparent thrombus in the right atrium prolapsing into the right ventricle. Intermittent loss of pacemaker sensing and capture was noticed on admission and probably caused the supraventricular tachycardia and ventricular fibrillation that occurred before an exploratory bypass operation. At operation rupture of the papillary muscle was found and the mitral valve was replaced. A large piece of thrombus was retrieved from the right pulmonary artery. The right heart contained no clot and the pacemaker wire was not displaced. It is envisaged that the strand of venous thrombus was caught in the permanent pacing wire at the tricuspid valve level resulting in an unusual case of pacemaker malfunction. The eventual poor outcome was almost certainly influenced by the arrhythmias and pulmonary embolism caused by the clot and might have been avoided by early operation.

Aged↗
PubMed1986

Enterocyte migration in the foetal sheep small intestine.

The migration of enterocytes was studied in the small intestine of foetal sheep at 115 and 136 days of gestation in utero. The speed of migration in all cases was slower than that reported in the adult. At 115 days, the migration rate was 4.88 and 4.96 percent villus height/day for the proximal and distal small intestine, respectively. At 136 days, the migration rate was significantly increased (p less than 0.05) to 12.0 for the proximal and to 8.5%, for the distal small intestine. Rates of villus length increase were between 0.007 and 0.012 mm/day over the time course studied. The migration rates, expressed as millimeters per day, were between 0.23 and 0.76 mm/day, hence the rate of migration was much greater (between 3 and 16 times) than the villus growth rate.

Animals↗
PubMed1986

Immunocytochemical localization of pro gamma MSH, gamma MSH, ACTH and beta endorphin/beta lipotrophin in the fetal sheep pituitary: an ontogenetic study.

An immunocytochemical staining technique was used to localize four fragments [pro gamma MSH, gamma MSH, ACTH and beta endorphin/beta lipotrophin (beta endorphin/beta LPH)] of the proopiomelanocortin molecule in both the adult and fetal sheep pituitary. In the adult sheep anterior pituitary each fragment was localized in cells that were darkly stained, stellate and widely distributed throughout the gland. The same cells, identified in three serial sections, stained with anti-pro gamma MSH, anti-ACTH and anti-beta endorphin/beta LPH. In the fetal sheep anterior pituitary all the proopiomelanocortin derived fragments were present at 38 days gestation. Between about 90 and 130 days of gestation both adult type proopiomelanocortin cells (small, stellate) and uniquely fetal cells (large, columnar) were present. Both adult-type and fetal proopiomelanocortin cells were identified in serial sections of the fetal anterior pituitary, stained with anti-pro gamma MSH, anti-ACTH and anti-beta endorphin/beta LPH. The adult intermediate lobe was immunoreactive with anti-pro gamma MSH and anti-beta endorphin/beta LPH but not with anti-gamma MSH or anti-ACTH. The fetal intermediate lobe was immunoreactive with all four antisera from 60 days gestation.

Adrenocorticotropic Hormone↗
PubMed1985

Immunohistochemical localization of ACTH in the adult and fetal sheep pituitary.

Light microscope peroxidase-antiperoxidase immunohistochemistry has been applied to the pituitary of adult and fetal sheep from 40 to 145 days of gestation. In the adult, immunoreactive ACTH cells were darkly stained and angular with cytoplasmic processes surrounding neighbouring unstained cells. In the fetus, cells which stained for ACTH were observed in the pars distalis at 40 days. From approximately 90 days, two morphologically distinct ACTH-positive cell types were clearly discernible. The predominant type was large and variably stained. These cells usually occurred in clusters and were often arranged in palisades. The other type resembled ACTH-positive cells in the adult. After 130 days the population of large cells declined and completely disappeared before term in most fetuses. The pars intermedia showed a different pattern of staining. In the fetus, ACTH-positive cells were observed in this region after 60 days gestation and by 90 days almost all the pars intermedia cells were strongly stained. By contrast, the cells in the adult pars intermedia were only lightly stained.

Adrenocorticotropic Hormone↗
PubMed1984

The pathology of psittacine beak and feather disease.

Psittacine beak and feather disease is characterised by loss of feathers, abnormally shaped feathers and overgrowth and irregularity of the surface of the beak. The disease occurs in a number of psittacine species including the Sulphur-crested Cockatoo, Lovebirds , Budgerigars and Galahs . The abnormal appearance of feathers and beak is due to a dystrophic process within the epidermis of the feather and beak. The process consists of epidermal cell necrosis, epidermal hyperplasia and hyperkeratosis. Many of the feather abnormalities are due to retention of a hyperkeratotic feather sheath. A characteristic microscopic finding is the presence of macrophages containing purple intracytoplasmic inclusions in affected epidermis and feather pulp. The inclusions consist of aggregates of particles 17 to 22 nm in diameter. Similar but smaller inclusions occur in epidermal cells. In addition, non-suppurative inflammation occurs in the feather pulp. The findings are suggestive of a viral infection.

Animals↗
PubMed1984

Toxicologic studies in a fatal overdose of 2,4-D, mecoprop, and dicamba.

A suicidal poisoning committed by a 61-year-old woman, who ingested an unknown quantity of Killex, containing in aqueous solution 100 g/L of (2,4-dichlorophenox)acetic acid (2,4-D), 50 g/L of mecoprop, and 9 g/L of dicamba as amine salts is described. Quantitation of chlorophenoxy acids was performed by extraction from an acidified mixture and concentration before high performance liquid chromatography analysis. All three herbicides were separated in a phosphate buffer/acetonitrile mixture at 280 nm on a RP-8 column. Concentrations of herbicides found were: in blood--520-mg/L 2,4-D, 530-mg/L mecoprop, and 170-mg/L dicamba; in urine--670-mg/L 2,4-D and 520-mg/L mecoprop; in bile--340-mg/L 2,4-D, 530-mg/L mecoprop, and 140-mg/L dicamba; and in liver--540-mg/Kg 2,4-D, 500-mg/Kg mecoprop, and less than 100-mg/Kg dicamba. Liquid chromatography was found to be a reliable method for herbicide quantitation in biological tissues and fluids. The technique offered definite advantages over ultraviolet spectrophotometry and avoids the derivatization requirement for gas chromatography.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1983

Ultrastructural detection of the onset of pituitary thyrotroph sensitivity to lowered thyroid hormone concentrations in the fetal sheep.

The goitrogen methylthiouracil was administered orally to pregnant ewes of known gestational ages to induce hypothyroidism in both mother and fetus. Developing pituitary thyrotrophic cells were studied using electron microscopy to detect the earliest gestational age at which morphological changes occurred in response to lowered plasma thyroid hormone concentrations. At 50 days of gestation, the pituitaries of fetuses exposed to the goitrogen were indistinguishable from untreated control glands. However, at 58 days and subsequent ages, "thyroidectomy' cells were observed in pituitaries of all hypothyroid fetuses. These findings indicate that fetal sheep pituitary thyrotrophs are sensitive to lowered thyroid hormone concentrations by 58 days of gestation, suggesting that thyroid-thyrotroph interaction exists at this early stage of development.

Animals↗
PubMed1982

Ultrastructure of the pars intermedia of the developing sheep hypophysis.

Using light and electron microscopy, the morphogenesis of the pars intermedia of the sheep pituitary gland was examined in developing lambs between 26 days of gestation and the newborn stage. Following the establishment of contact between the anterior and posterior lobe primordia seen at 26 days, the connection with the pharyngeal roof disappeared by 31 days. The lumen of Rathke's pouch, which was a prominent cavity at the earlier stages, became inconspicuous by 40 days but progressively increased in size during gestation and, in some newborn animals, contained colloid material. At 40 days the pars intermedia consisted of a uniform population of undifferentiated cells. Cells with cytoplasmic granules were first identified at 50 days. The cytological appearance of granular cells at 70 days indicated increased synthetic activity and by 80 days they closely resembled adult glandular cells. At 100 days, membrane activity suggestive of exocytosis was first observed in granular cells; fenestrated capillaries were present, and early follicle formation between adjacent non-granular cells was seen. This apparent exocytotic release of granules was observed much more frequently between 100 days of gestation and the newborn stage than in adult pars intermedia cells. These findings indicate that glandular cells of the developing pars intermedia are actively engaged in synthesis, storage and secretion from an early stage.

Animals↗
PubMed1981

Ultrastructure of the pars intermedia of the adult sheep hypophysis.

Light microscopy of coronal sections of the sheep pars intermedia revealed a compact, incompletely lobulated V-shaped region about 15-20 cells thick, situated between the pars distalis and the pars nervosa. A prominent hypophysial cleft and follicles containing a colloid-like substance were seen. Using electron microscopy, five cell types could be distinguished: pars intermedia glandular cells, pars distalis-like glandular cells, interstitial cells, follicular cells and cleft lining cells. The polyhedral to pear-shaped pars intermedia glandular cells predominated. They contained dense-cored, membrane-bound granules near the Golgi complex, and larger, irregular vesicles with finely granular contents of varying electron density throughout the remaining cytoplasm; exocytotic release of granules was occasionally observed. Smaller numbers of cells resembling those seen in the pars distalis were scattered throughout the pars intermedia. Interstitial cells usually possessed elongated cytoplasmic processes which extended between the glandular cells, and were characterized by deeply indented nuclei, elaborate junctional complexes and an absence of cytoplasmic granules. Cells lining the follicles resembled the interstitial cells. The major cells bordering the hypophysial cleft were triangular in section and bore irregular microvilli on their free surface. The pars intermedia appeared to be less vascular than the remainder of the hypophysis and only occasional fenestrated capillaries were seen. Nerve profiles were rare.

Animals↗
PubMed1977

On the reactivities of the tryptophan residues of human alpha-lactalbumin to 2-hydroxy-5-nitrobenzyl bromide.

The reaction of human alpha-lactalbumin with the tryptophan reagent 2-hydroxy-5-nitrobenzyl bromide has been studied. This protein has 3 tryptophan residues (Trp-60, Trp-104 and Trp-118) all of which are accessible to the reagent at pH 2.7 or 7. Trp-60 of human alpha-lactalbumin is much more reactive than Trp-60 of bovine alpha-lactalbumin (Barman, T. E. (1972) Biochim. Biophys. Acta 257, 297-313). As with bovine alpha-lactalbumin, at pH 2.7, 2-hydroxy-5-nitrobenzyl bromide is specific for tryptophan but at pH 7 His-32 also reacts. When treated with the tryptophan reagent, both alpha-lactalbumins lose their specifier protein activities in the lactose synthase (UDPgalactose:D-glucose 4-beta-galactosyltransferase, EC 2.4.1.22) reaction.

2-Hydroxy-5-nitrobenzyl Bromide↗
PubMed1975

Histochemically detected differences in cultured sympathetic neurons.

Fetal or newborn rat and guinea-pig sympathetic ganglia were cultured in Rose chambers. After periods of up to 14 days in vitro, cultures were processed for catecholamine fluorescence or acetylcholinesterase histochemistry. The two types of neuron previously identified showed different histochemical reactions. The less frequent, smaller Type I cells contained catecholamine but did not stain for acetylcholinesterase. These cells may be immature. The more common Type II cells showed reactions for both catecholamine and acetylcholinesterase and in this respect resembled mature ganglion cells.

Acetylcholinesterase↗
PubMedDate not supplied

Distribution of trimipramine and its major metabolites in a fatal overdose case.

A fatality following ingestion of the tricyclic antidepressant trimipramine (Surmontil) is described. Quantitation was performed by high-performance liquid chromatography. Trimipramine and desmethyltrimipramine concentrations were 4.8 and 2.1 mg/L, respectively, in postmortem blood. The concentration of trimipramine, desmethyltrimipramine, and their respective 2-hydroxy metabolites were also measured in liver and urine. Analysis of gastric contents revealed a tricyclic antidepressant drug. These findings are compared to previously published reports of trimipramine-related fatalities.

Adult↗