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Biomedical subjects

P Yang

Publications and source records attributed to P Yang.

At least 361 records · Page 20Linked to original sources
PubMed1984

Polyamines and intestinal growth: absolute requirement for ODC activity in adaptation during lactation.

Ornithine decarboxylase (ODC), through the regulation of polyamine biosynthesis, is important in cell proliferation and differentiation. We followed intestinal mucosal ODC activity in lactating Lewis rats and correlated the ODC levels with the characteristic small intestinal adaptive changes accompanying lactation. During the first 14 days of lactation, mucosal ODC activity increased, with the maximal increase on day 5 corresponding to the time of maximal morphological intestinal adaptation. In animals given the specific inhibitor of ODC, alpha-difluoromethylornithine (DFMO), intestinal mucosal ODC activity was inhibited, and intestinal adaptation was suppressed, with marked diminution of the adaptive increase in mucosal weight and thickness especially in crypt depth. Our results suggest that ODC activity plays an essential role in mucosal hyperplasia during the intestinal adaptation accompanying lactation, possibly through the stimulation of crypt cell proliferation.

Adaptation, Physiological↗
PubMed1984

Esophageal Lewy bodies associated with ganglion cell loss in achalasia. Similarity to Parkinson's disease.

Achalasia and Parkinson's disease sometimes have similar clinical and neuropathologic features, including loss of esophageal peristalsis and neuronal loss within brainstem nuclei. We compared the neuropathologic features in autopsies of 8 achalasia patients, 22 Parkinson's disease patients (3 patients with dysphagia), and 50 age- and sex-matched controls. Degenerating ganglion cells in the esophageal myenteric plexus in 2 achalasia patients contained Lewy bodies, intracytoplasmic inclusions characteristically found in the brainstem in Parkinson's disease. Esophageal or colonic Lewy bodies were also found in 2 Parkinson's disease patients with dysphagia. No gastrointestinal tract Lewy bodies were identified in Parkinson's disease patients without dysphagia or in controls. One achalasia patient with esophageal Lewy bodies also had the inclusions and neuronal depigmentation in the vagal dorsal motor nucleus and substantia nigra, as seen in Parkinson's disease. Our findings indicate that a subset of achalasia and Parkinson's disease patients with dysphagia may have similar mechanisms of neuronal degeneration responsible for esophageal dysfunction.

Adult↗
PubMedDate not supplied

Aesthetic reconstruction of burn alopecia by using expanded hair-bearing scalp flaps.

Tissue expansion is one of the most important armamentaria for aesthetic scalp reconstruction after burn; however, the proper way to employ this technique for the scalp reconstruction usually presents a challenge to the plastic surgeon, especially in the case of a "sideburn" scenario or a large lesion, as with, for example, hemiscalp alopecia. In this article, 11 patients, with different degrees of hair-bearing scalp loss as a result of burn, and including four patients with hemiscalp alopecia were successfully treated by using tissue expansion. The results show that tissue expansion is a simple, safe, and efficient technique for aesthetic scalp reconstruction. Versatile design of the expanded scalp flap can distribute the expanded hair-bearing scalp properly in the reconstructed recipient site.

Adolescent↗
PubMedDate not supplied

Colonic lipomas: outcome of endoscopic removal.

Colonic lipomas are benign adipose tumors which are usually submucosal. With the increase in the number of endoscopic procedures being performed, these tumors are often detected incidentally at colonoscopy. Although the risks of removing these tumors have been recognized, numerous reports have documented safe removal by snare electrocautery. We have reviewed the clinical outcome and the endoscopic and histopathologic features of seven lipomas that were endoscopically removed over a 5-year period. Four patients recovered uneventfully, while three patients (42.8%) developed colonic perforation after the polypectomy. In the latter group, the lipomas were significantly larger than they were in the patients who did not develop colonic perforation (1.9 +/- 0.4 and 4.2 +/- 0.7 cm, respectively; p = 0.048). Furthermore, the polypectomy specimens from those patients who developed perforation all contained significant muscularis propria. Lipomatous polyps that are identified at endoscopy to be greater than or equal to 2 cm in diameter and to have a limited pedicle are at the greatest risk for endoscopic perforation.

Aged↗
PubMedDate not supplied

NMDA receptor antagonist disrupts acute and chronic effects of methylphenidate.

Methylphenidate (MPD) is a drug widely used for treating attention-deficit/hyperactivity disorder in children. Because of its extensive consumption and because it has pharmacological stimulant properties similar to amphetamine and cocaine, MPD has the potential of abuse. N-methyl-D-aspartate (NMDA) receptors are suggested to be involved in CNS effects of stimulants, and antagonists of the NMDA receptor can potentially alter the stimulants' effects. Dizocilpine (MK-801), a non-competitive antagonist of the NMDA receptor, has been reported to prevent sensitization elicited by repeated administration of amphetamine and cocaine. The objective of the present study was to use the tail-flick latency assay, rectal temperature, and body weight gain to assess effects of repetitive treatment of MPD and whether MK-801 treatment would alter these effects in Sprague-Dawley rats. It was found that: (Ia) Acute administration of MPD or MK-801 did not alter the tail-flick latency, (Ib) Repeated administration of MPD decreased tail-flick latency, while repeated administration of MK-801 had no significant effect on tail-flick latency, (Ic) MK-801 given prior to or with MPD reversed the chronic effect on tail-flick latency produced by MPD; (IIa) When both drugs were independently given, MPD elicited a decrease in rectal temperature, while MK-801 alone produced an increase in temperature, (IIb) When given together, MK-801 had a transient effect in blocking the sensitization to MPD but failed to reverse the sensitization of MPD once it had developed; and (III) Both MK-801 and MPD caused an unstable pattern of body weight gain. Hence, the results of this study in rats suggest that MK-801 can modulate non-motor effects of MPD.

Analgesics, Opioid↗
PubMedDate not supplied

A case report of frosted branch angiitis and its visual electrophysiology.

We reported a 5-years old boy with frosted branch angiitis in both eyes. The visual acuities of the two eyes were suddenly lost to 5/50. The fluorescein angiography, electroretinograms (ERGs) and pattern evoked potentials (PVEPs) had been tested at the acute and the recovery stage of the disease. At the onset of the disease, fluorescein angiography showed obvious dye leakage from dilated retinal veins. The PVEPs and whole field ERGs including rod, maximum, OPs and cone responses were seriously decreased and prolonged, indicating that the visual pathway's and retinal functions were greatly damaged. The patient had an excellent response to systemic prednisone. One month after the treatment, the visual acuities recovered to 60/50 in both eyes. The fluorescein angiography showed that leakage from blood vessels was diminished, but the lesions at macula and optic disc were persisted a longer time even to the end of treatment. Through 6 months medication, nearly all of the electrophysiological abnormalities had been resolved.

Administration, Oral↗
PubMedDate not supplied

Disordered eating in Japanese and Chinese female runners, rhythmic gymnasts and gymnasts.

Eating Attitude Test-26 (EAT-26) and self-administered questionnaires were used to survey eating attitudes and menstrual irregularity of Japanese (J) and Chinese (C) collegiate female runners (RUNs), rhythmic gymnasts (RGYMs), gymnasts (GYMs), and nonathletic controls (NAs). Athletes were recruited from several outstanding colleges for physical education and sport in each country. The prevalence of disordered eating (DE) was significantly higher in Japanese athletes (21% in JRUNs, 19% in JRGYMs, and 15% in JGYMs) than Chinese athletes (4% in CRUNs, 2% in CRGYMs, and none in CGYMs). Also, the prevalence of amenorrhea was very low in CRUNs (1%), CRGYMs (0%), and CGYMs (0%), as compared with their respective Japanese counterparts (JRUNs 22%, JRGYMs 10%, JGYMs 8%). There was no significant difference in the prevalence of DE and amenorrhea between Japanese and Chinese NAs. Multivariate logistic regression analysis using 10 independent variables regarding anthropometrics, athletics, weight and diet concern, and nationality indicated that high frequency of dieting during a lifetime, high athletic level and being Japanese were significant risks for the development of DE in athletes. It is concluded that the low prevalence of DE in the Chinese in this study is partly explained by the lack of socioculturally- and socioeconomically-imposed desire to be thin as well as by the low frequency of dieting during their lifetime.

Amenorrhea↗
PubMedDate not supplied

Pulmonary blastoma: an ultrastructural and immunohistochemical study with special reference to nuclear filament aggregation.

A case is presented of pulmonary blastoma occurring in the right upper lobe of a 25-year-old man without distinct clinical features and laboratory abnormality. Light microscopic analysis revealed that the tumor was composed of branching glands and morulae embedded in a primitive but bland mesenchyme. Immunohistochemically the epithelial cells were immunoreactive for cytokeratins, S-100 protein, protein gene product 9.5, chromogranin A, calcitonin, and Ki-67 (MIB-1); the mesenchymal cells were immunoreactive for vimentin, actin, cytokeratins, and Ki-67; and all the tumor cells were negative for p53, estrogen receptor protein, and human chorionic gonadotropin beta. Characteristically, many epithelial cells contained optically clear nuclei which were immunoreactive for biotin (M743). Electron microscopic analysis revealed that the optically clearing change was due to replacement of the central area of the nuclei by a mass of parallel-arranged 7- to 10-nm filaments, and biotin-immunoreactive products were mainly localized in the nuclear matrix. Additionally, spherical bodies were identified in the cytoplasm of the nuclear filament-aggregated cells, suggestive of an intimate pathogenetic association of the two morphological abnormalities. The similarity of the aggregated nuclear filaments to those observed in gestational endometrium and ovarian endometrioid carcinoma implies that a similar mechanism plays a role in the pathogenesis of these abnormalities.

Adult↗
PubMedDate not supplied

Ultrastructural heterogeneity of acquired intradermal melanocytic nevus cells.

The present ultrastructural evaluation of 12 acquired intradermal melanocytic nevi revealed that in contrast to the nested epithelioid melanocytic nevus cells of the upper dermis, the spindle nevus cells of the deep dermis showed perineurial differentiation, exhibiting a spindly configuration characterized by a melanosome-free cytoplasm that showed extremely slender bipolar contour and contained abundant intermediate filaments, a decreased number of cytoplasmic organelles, and, significantly, a fair number of plasmalemmal pinocytotic vesicles. The nevic corpuscles were found to consist of laminated slender cytoplasm showing subcellular conformation similar to that of the spindle nevus cells. By immunohistochemistry, many spindle nevus cells and nevic corpuscles were immunoreactive for nerve growth factor receptor. All the nevus cells were immunoreactive for vimentin and S-100 protein, and negative for protein gene product 9.5, epithelial membrane antigen, Leu-7, and myelin basic protein. Characteristically, protein gene product 9.5 immunohistochemistry revealed numerous immunoreactive axons intermingled with the spindle nevus cells in the deep portion. All the PGP9.5-immunoreactive axons were observed by immunoelectron microscope to be unmyelinated and always ensheathed by a thin cytoplasmic process of Schwann cells but not nevus cells. These findings indicate that differentiation plasticity exists in the various nevus cells, with the epithelioid nevus cells and the spindle nevus cells displaying more ultrastructural and immunophenotypical characteristics of melanocyte and perineurial cells, respectively, suggesting that a pluripotential cell of neural crest origin accounts for the histogenesis of this lesion.

Humans↗