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Biomedical subjects

S M Chang

Publications and source records attributed to S M Chang.

At least 109 records · Page 6Linked to original sources
PubMed1995

Sarcomas subsequent to cranial irradiation.

The development of sarcoma subsequent to cranial irradiation is a rare but serious and potentially fatal event. We describe seven patients who had undergone cranial irradiation (range, 1600-6000 cGy) to treat their primary disease and who developed sarcomas within the irradiated field. The median time from radiation therapy to the development of a sarcoma was 8 years (range, 4 to 15 yr). Fibrosarcomas developed in four patients, and malignant fibrous histiocytomas developed in three. Despite aggressive treatment, the prognosis was poor; the median survival from the diagnosis of sarcoma was 19 months. Sarcoma should be considered in the differential diagnosis of a new lesion or a lesion that progresses several years after radiation therapy.

Adolescent↗
PubMed1995

Pineoblastoma in adults.

This is the first report of a series of adults (> 16 years of age) with pineoblastomas who had their entire neuraxis staged at the time of diagnosis. Between 1975 and 1992, seven men and four women with histologically proven pineoblastomas were evaluated at the University of California, San Francisco. The median age at diagnosis was 36 years (range, 17-59 yr). All patients presented with symptomatic hydrocephalus. One patient had a complete surgical resection, eight had subtotal resections, and two had biopsies only. One patient refused any treatment or follow-up review and died 6 months after diagnosis. The five patients with positively staged disease had progression either focally or in the spine 8 to 49 months (median, 10 mo) after initial diagnosis and died 1 to 20 months after recurrence; the median overall survival time from the date of surgery was 30 months. In contrast, all five patients with negatively staged disease were alive without disease progression after a median of 26 months of follow-up. Our retrospective review shows that the extent of disease at diagnosis seems to be an important prognostic factor for pineoblastomas, as is true for medulloblastomas and other primitive neuroectodermal tumors. Initial staging should include examination of the cerebrospinal fluid and magnetic resonance imaging of the spine. Although patients with pineoblastomas are often treated with adjuvant systemic chemotherapy after craniospinal irradiation, the benefits of this approach are unclear.

Adolescent↗
PubMed1995

Comparison of amlodipine and quinapril on ambulatory blood pressure and platelet function in hypertension.

The effect of calcium channel blocker (CCB), amlodipine (5-10 mg/day) and angiotensin-converting enzyme (ACE) inhibitor, quinapril (10-40 mg/day) on ambulatory blood pressure (ABP), rheological and platelet function in hypertension were compared in this randomised double-blind placebo-controlled cross-over study. This study was preceded by 4 weeks placebo run-in period and the total duration of the study was 28 weeks. Casual and 24 h ABP, plasma renin activity (PRA) and plasma aldosterone (PA) concentration as well as metabolic and platelet function were determined before and at the end of each drug therapy. A total of 27 patients completed this study. Casual BP was significantly reduced after amlodipine or quinapril treatment, but there was no change in heart rate. Regarding the 24 h ABP, amlodipine produced a fall from 145 +/- 8/94 +/- 7 to 130 +/- 13/85 +/- 10 mm Hg (P < 0.001 for both SBP and DBP). Quinapril also caused a reduction from 144 +/- 10/94 +/- 7 to 134 +/- 12/88 +/- 8 mm Hg (P < 0.001 for both SBP and DBP). Neither amlodipine nor quinapril produce any significant change in heart rate. The level of 6-keto-prostaglandin Fl alpha (6-Keto-PGFl alpha) was increased from 36.8 +/- 4.4 to 45.1 +/- 2.5 pg/ml (P < 0.05) and no significant change of thromboxane B2(TXB2) was noted after amlodipine treatment. PRA was increased from 1.24 +/- 0.31 to 1.62 +/- 0.41 ng/ml/h (P < 0.05) after quinapril treatment. Other biochemical parameters were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Activity and behavioral development in stunted and nonstunted children and response to nutritional supplementation.

It is frequently assumed that undernutrition in young children leads to poor development through reduced activity. 3 groups of 26 1-year-old stunted children were studied: nutritional supplementation, supplementation with psychosocial stimulation, and controls. 26 nonstunted comparison children were also studied. Activity levels were measured by extensive observation in the homes, and development using 4 subscales of the Griffith's Mental Development Scales. Initially, stunted children were less active than nonstunted ones (p < .01), but after 6 months they caught up regardless of treatment. The mental ages of the stunted children were lower than those of the nonstunted children initially, and improved with either treatment. Initially, activity levels made a significant contribution to the variance in the locomotor subscale only, but not 6 months later. Activity did not predict change in development over 6 or 12 months, nor did change in activity over 6 months predict change in development over 12 months.

Child Behavior Disorders↗
PubMed1994

Androgen-independent cancer progression and bone metastasis in the LNCaP model of human prostate cancer.

Our laboratory has previously reported on the derivation of LNCaP cell sublines from LNCaP tumors maintained in castrated and intact athymic male mice. These LNCaP sublines differ from the parental line in tumorigenicity and androgen dependence. This paper demonstrates that one of these sublines acquired metastatic potential. When inoculated either s.c. or orthotopically, the C4-2 subline metastasized to the lymph node and bone with an incidence of 11-50%. Interestingly, the incidence of osseous metastasis was higher in castrated than in intact male hosts. We evaluated the chromosomal, immunohistochemical, and biochemical characteristics of the LNCaP sublines derived from C4-2 tumors that metastasized to the lymph node and bone. Cytogenetic analysis showed that all sublines were human and shared common marker chromosomes with the parental LNCaP cells. This experimental human prostate cancer model may permit, for the first time, the study of the molecular mechanisms underlying human prostate cancer metastasis.

Animals↗
PubMed1994

Malignant peripheral nerve sheath tumor: a study of 21 cases.

BACKGROUND: Malignant peripheral nerve sheath tumor (MPNST) is an aggressive tumor of neural origin. To improve our experience with this rare tumor, we reviewed 21 patients seen during a 12-year period at the pathological department of Taichung Veterans General Hospital. METHODS: Clinical data including age, sex, presence or absence of von Recklinghausen's disease, tumor location and size, presenting symptoms, surgical management and surveillance were summarized. Microscopically, we examined necrosis, mitosis, differentiation, the resection margin, and the presence or absence of neurofibromatous component. RESULTS: There were 15 males and 6 females with age range of 9-86 years. Seven cases were associated with neurofibromatosis and 14 cases were solitary MPNST: Patients with coexistent neurofibromatosis were younger (mean age at diagnosis, 32 years) than patients with solitary MPNST (mean, 60.2 years). Tumors of the former group tended to be centrally located. Anaplastic alteration was found in the recurrent tumors of two patients both of whom died of the disease. Of the 21 cases, epithelioid differentiation and osteoid metaplasia were seen in two tumors respectively by optical microscopy. Patients with von Recklinghausen's disease and large incompletely resected tumors had the most dismal prognosis. Of five patients with neurofibromatosis who were observed for more than two years, only one survived and no recurrence was found. The remaining four patients died within 3-9 months. However, of 14 cases of solitary MPNST, only two patients died of disease and ten of them had survived beyond two years. CONCLUSIONS: Our work revealed that patients with von Recklinghausen's disease, a large unresectable centrally located tumor with diffuse anaplastic alteration, had frequent recurrences and poor prognosis. Aggressive surgical procedure with free resection margin is suggested. Malignant transformation should be highly suspected when a painful, rapidly growing tumor developed.

Adolescent↗
PubMed1994

Diffuse pigmented villonodular synovitis of the shoulder: a case report.

Pigmented villonodular synovitis (PVNS) of the shoulder is an uncommon disorder with unknown etiology. It is characterized by synovial proliferation and hemosiderin deposition into the synovial tissues of the affected joints. PVNS affects mainly the knee joint and shoulder involvement is rare. There are only 12 cases of shoulder involvement reported in the English-language literature. A case of PVNS of the shoulder with simultaneous rotator cuff tear is presented and the literature is reviewed.

Humans↗
PubMed1993

Structure-activity relationships of serotonin transport: relevance to nontricyclic antidepressant interactions.

A transfectant cell model was used to examine the structure-activity relationships of serotonin (5-hydroxytryptamine, 5-HT) transport. The findings suggest that 5-HT interacts largely with nonpolar and sterically-confining environments on the transport system, and that a particular spatial coordination of the amino and phenyl groups (separated by an alkyl backbone) is important for transport interaction. Molecular modelling analyses revealed that this motif is also present in the structures of several nontricyclic antidepressants and specific inhibitors of 5-HT transport, as well as adrenergic agents which also possess 5-HT transport-inhibitory activities. While this amino-phenyl coordination motif seems to be a necessary structural requisite for transport interaction, and therefore likely to be part of the transport pharmacophore, additional phenyl rings present in some of the nontricyclic antidepressants may help to account for their relatively higher affinities in 5-HT transport interaction.

Animals↗
PubMed1993

Cross-reactive lysis of human targets infected with prototypic and clinical human immunodeficiency virus type 1 (HIV-1) strains by murine anti-HIV-1 IIIB env-specific cytotoxic T lymphocytes.

To evaluate the ability of murine anti-human immunodeficiency virus type 1 (HIV-1) IIIB env cytotoxic T lymphocytes (CTL) to recognize and lyse HIV-1-infected cells, we have constructed a human cell line (Hu/Dd) expressing both the CD4 receptor and the murine H-2Dd major histocompatibility complex (MHC) class I protein. This cell line can be productively infected with HIV-1 and can also function as a target for murine CD8+, class I MHC-restricted CTL directed against the envelope glycoprotein of HIV-1 IIIB. The ability of BALB/c anti-HIV-1 IIIB env CTL to specifically recognize and lyse Hu/Dd target cells infected with divergent HIV-1 strains was tested by using both prototypic and clinical HIV-1 strains. CTL generated by immunization of mice with syngeneic cells expressing either the native or V3 loop-deleted (delta V3) envelope glycoprotein from HIV-1 IIIB were able to recognize and specifically lyse Hu/Dd target cells infected with the HIV-1 prototypic isolates IIIB, MN, WMJ II, SF2, and CC as well as several HIV-1 clinical isolates. These results demonstrate that CTL determinants for HIV-1 env exist outside the hypervariable V3 region, anti-HIV-1 IIIB env CTL appear to recognize common determinants on diverse HIV-1 strains, and classification of HIV-1 strains based on neutralizing antibody reactivities does not appear to correspond to CTL recognition and lysis. The results suggest that the cell-mediated components of the immune system may have a broader recognition of divergent HIV-1 strains than do the humoral components.

Animals↗
PubMed1993

Glomus tumor of the stomach: a case report.

The histologic and ultrastructural features of a gastric glomus tumor are presented with a brief review of the literature. Initially interpreted as carcinoid, the tumor occurred in a 41-year-old female who was first diagnosed by radiological examination and microscopic histological study of an endoscopic biopsy specimen. Glomus tumor was confirmed by further study of multiple sections of a surgical specimen and by electron microscopy. Correct identification of this essentially benign, very rare gastric tumor can prevent unnecessary radical operative procedures.

Adult↗
PubMed1992

Oxytocin and bovine parturition: a steep rise in endometrial oxytocin receptors precedes onset of labor.

Oxytocin receptors were measured in myometrium and intercaruncular endometrium of cows during pregnancy and parturition. Concentrations of estradiol-17 beta, estrone, and progesterone in peripheral blood were also measured. Receptor concentrations in the endometrium rose almost 200-fold from Day 20 to term (p < 0.0001, ANOVA), from 40 +/- 11 to 7300 +/- 1430 fmol/mg protein. Myometrial receptor concentrations increased 10-fold from 180 +/- 36 fmol/mg on Day 20 to 1850 +/- 360 fmol/mg protein at term (p < 0.0001, ANOVA). During labor, endometrial receptors (6600 +/- 1300 fmol/mg) remained at prelabor values, whereas myometrial receptor concentrations had decreased to 1190 +/- 316 fmol/mg (not significant) and declined further postpartum. Plasma concentrations of progesterone declined from 4-5 ng/ml to about 2 ng/ml between Days 250 and 282 and dropped to < 0.2 ng/ml shortly before delivery. Plasma concentrations of estrone and estradiol-17 beta were below 10-20 pg/ml until Day 230. Estrone concentrations were significantly (p < 0.05) increased by Day 250 and estradiol-17 beta by Day 270, and then both rose rapidly. During labor, plasma estrone was 1135 +/- 245 pg/ml and plasma estradiol-17 beta was 226 +/- 131 pg/ml. The molar ratio of estrone and estradiol-17 beta to progesterone rose from less than 0.01 to 4.4 during labor, and was correlated with oxytocin receptor concentrations in endometrium (r = 0.5160, p < 0.001), but not those in myometrium (r = 0.0122). The regulation of oxytocin receptors by ovarian hormones in the two tissues may therefore differ.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Concentration of oxytocin receptors in the placenta and fetal membranes of cows during pregnancy and labour.

The concentrations of oxytocin receptors were measured in intercaruncular and caruncular endometrium, fetal cotyledons, chorioallantois and amnion during pregnancy and parturition in cows. Tissues were obtained on days 20 (endometrium only), 50, 100, 150, 200, 225, 250, 275, at term (days 280-284), during labour and within 24 h after calving. Receptor concentrations in intercaruncular endometrium were low on day 20 of pregnancy, 39 +/- 11 fmol mg-1 protein. By day 50, receptor concentrations had increased more than tenfold to 572 +/- 52 fmol and rose steadily until day 250 and then levelled off at about 4500 fmol mg-1. Shortly before parturition, on day 282 +/- 1, a further rise to 7300 +/- 1418 fmol mg-1 was observed, these concentrations were maintained throughout labour. By contrast, caruncular endometrial receptor concentrations remained low until term, mean 145 +/- 15 fmol mg-1, and then rose to 720 +/- 163 fmol mg-1 during labour (cervix 17 cm--fully dilated). Fetal cotyledons and membranes had very low oxytocin receptor concentrations during most of pregnancy, on average only 20 fmol mg-1 protein. At term and during labour, receptor concentrations were significantly increased in both tissues. Mean concentrations during labour were 163 +/- 36 fmol mg-1 for cotyledons, 270 +/- 61 fmol mg-1 for chorioallantois and 311 +/- 121 fmol mg-1 for amnion.(ABSTRACT TRUNCATED AT 250 WORDS)

Allantois↗
PubMed1992

[Effect of gossypol on the proliferation of rat prostate cells studies in vivo and in vitro].

The effect of gossypol on prostate cells of rat was studied both in vitro and in vivo. For in vivo study, mature male Sprague Dawley rats were given gossypol orally, 5 mg/day, 5 times a week for one month. Then the prostates were examined histologically. By adding gossypol to the culture system directly, NbE-1 cells were used in vitro study. Several parameters, including histological structure, cell growth, DNA synthesis and mitotic cycle of cells were measured by different methods. The prostate size and weight in experimental rats decreased and significant differences between acini in controls and gossypol treated animals were noted. Acini of control prostate were full of protruding folds constituted by columnar epithelial cells, whereas, the most of the acini in treated animals were composing of cubic or square epithelial cells and epithelial folds were rarely seen. Thus, acini with normal appearance were about 14% less than that in controls. In the in vitro experiments, both cell proliferation and DNA synthesis decreased from 0 to 80% and from 0 to 90% respectively, when the concentrations of gossypol were increased from 0 to 20 micrograms/ml. It seems that 10 micrograms/ml of gossypol could cause the most significant inhibition in these two cellular functions. The cell mitotic assay showed that in treated groups, the cell number of S phase was decreased from 43 to 31%, this fact indicated that the inhibition on cell proliferation caused by gossypol might be due to preventing cells to enter S phase. Besides, inhibition effect on the proliferation of prostatic epithelial cells was dosage dependent and related to the duration of treatment.

Animals↗
PubMed1991

Intracranial lipoma in the medulla oblongata.

Intracranial lipoma in the medulla oblongata has been rarely reported. Only two cases have been documented in the literature. This report concerns a patient who complained of nuchal soreness and an unstable gait for 6 months. An olivelike lipoma, arising from the posterior aspect of the medulla oblongata and embedded in the lower cranial nerves, was found at suboccipital craniectomy and posterior laminectomy of C1-2. Partial removal of the lipoma was performed for decompression; radical removal would have been hazardous. The clinical symptoms subsided postoperatively. The computed tomography scan and magnetic resonance image proved useful for properative diagnosis.

Aged↗
PubMed1991

Nutritional supplementation, psychosocial stimulation, and growth of stunted children: the Jamaican study.

The benefits of nutritional supplementation, with or without psychosocial stimulation, on the growth of stunted children were evaluated. Children aged 9-24 mo with lengths less than -2 SD of the National Center for Health Statistics references (n = 129) were randomly assigned to four groups: control, nutritional supplementation, stimulation, and both interventions. A fifth group with lengths greater than -1 SD was also enrolled. Length, weight, head and arm circumferences, and triceps and subscapular skinfold thicknesses were measured on enrollment and 6 and 12 mo later. Multiple-regression analysis was used to determine the effects of the interventions in which age, sex, initial status, initial dietary intake, and several socioeconomic variables were controlled for. Stimulation had no effect on growth and there was no interaction between the interventions. After 12 mo supplemented children had significantly increased length, weight, and head circumference (all P less than 0.01). The effects of supplementation were not cumulative but occurred in the first 6 mo.

Female↗