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Biomedical subjects

A Sun

Publications and source records attributed to A Sun.

At least 91 records · Page 5Linked to original sources
PubMed1991

Mechanisms of depressed natural killer cell activity in recurrent aphthous ulcers.

Natural killer (NK) cell activity was studied serially in the peripheral blood obtained from 35 patients with recurrent aphthous ulcers (RAU) and from 46 age/sex-matched normal healthy controls. The NK cell activity was assayed by a 4-hr 51Cr release assay using K562 cells as targets. The results showed that the patients in remission (2 weeks of convalesence) had normal NK cell activity compared to that of normal controls. Four stages of evolution (early, exacerbation, postexacerbation, and convalescence) in these patients were further evaluated. Increased NK cell activity in the exacerbation of major aphthous ulcer was noted. In contrast, depressed NK cell activity in postexacerbation and in 1 week of convalescence was found at different effector/target (E/T) ratios. The depressed NK cell activity was interpreted as temporary and a secondary phenomenon in the immunopathogenesis of this disease. Partial restoration of depressed NK cell activity by adding recombinant interleukin-2 (rIL-2) suggests that other factors are also involved in the process or that IL-2 deficiency exists in RAU patients. However, no deficiency of plasma IL-2 and interferon-gamma (IFN-gamma) was noted. The percentage of large granular lymphocytes (LGL, NK/K) was correlated with NK cell activity, with both parameters being depressed in the postexacerbation of RAU patients. NK cell activity of RAU patients was still depressed after the depletion of plastic adherent cells. Suprisingly, in contrast to the remission stage, unresponsiveness to rIL-2 of normal NK cell activity in the exacerbation stage was found. The discrepancy was not associated with different subpopulations of NK heterogeneous cells. Immunopathogenesis of RAU on the NK-IFN-IL-2-IL-2R system needs further clarification.

Adolescent↗
PubMed1991

Strong association of HLA-DRw9 in Chinese patients with recurrent oral ulcers.

The frequency of HLA-DR and -DQ antigen occurrence was investigated in 80 Chinese patients with recurrent oral ulcers and 107 matched healthy control subjects of the same ethnic group. No significant differences in the presence of HLA-DQ antigens were found. However, the HLA-DRw9 antigen occurs more frequently in patients with recurrent oral ulcers (p less than 0.0001, corrected p less than 0.005) and may be considered as a genetic marker of the disease in the Chinese population.

Adult↗
PubMed1991

Xenotransplantation of microencapsulated fetal rat islets.

Fetal pancreatic islets were isolated from 21-day pregnant Wistar rats and enclosed in semipermeable alginate-polylysine-alginate capsules. Encapsulated islets that had been previously cultured for eight days in vitro were shown to secrete insulin in response to glucose challenge: low-glucose, high-glucose, and high-glucose + 3-isobutyl-1-methyl-xanthine (IBMX). Transplants of 800-1000 encapsulated cultured fetal islets into the peritoneal cavities of BALB/c mice with streptozotocin-induced diabetes restored normoglycemia for up to 171 days without immunosuppression. When the capsules were removed from 2 of the recipients they both quickly regressed to a diabetic state. Control groups of diabetic mice received unencapsulated, uncultured islets or empty capsules. The mortality rate among these animals was high and none experienced relief from hyperglycemia for longer than 6 days. These results demonstrate that cultured microencapsulated fetal rat islets of Langerhans can release insulin in response to an in vitro glucose challenge, and that transplants of these islets into diabetic mice can restore normoglycemia without the need for immunosuppressive therapy.

Alginates↗
PubMed1991

[Treatment of gynecological diseases by laparoscopic operation].

A series of 101 cases of gynecological diseases were treated laparoscopically by Nd: YAG laser (n = 68), electrocautery (n = 23) and microwave (n = 10) from September 1989 to November 1990 at PUMC Hospital in Beijing. This series included 64 patients with endometriosis, 17 with ectopic pregnancy, 13 with paraovarian cysts and other ovarian cysts; 4 with hydrosalpinx; 2 with subserosal myomata and 1 with polycystic ovary disease. All the operations were performed under local and topical anesthesia with procaine and dicaine respectively. Follow-up for 2-16 months revealed that, all the cases of endometriosis and other ovarian cysts produced good results. The patients of ectopic pregnancy were treated successfully by mere laparoscopy without laparotomy. No operative complications occurred. The technique, indications and characteristics of the operations are discussed.

Adult↗
PubMed1990

HLA-DR and DQ antigens in Chinese patients with oral lichen planus.

A study of HLA-DR and DQ typing in 44 patients with oral lichen planus (OLP) (28 women and 16 men) and in 107 normal controls of both sexes was performed by using Terasaki's oriental tray. Twenty-eight patients had erosive forms of lichen planus (OLPe). Serologic typing revealed a highly significant increase of HLA-DR 9 and Te 22 antigens in the patient group. Considering our findings and those in other autoimmune diseases, it is hypothesized that OLP is a localized autoimmune disease and the HLA-DR9 in Chinese takes the place of HLA-DR3 in Caucasians in carrying the genes which predispose to the development of autoimmune disease.

Epitopes↗
PubMed1990

Endobronchial tuberculosis--is corticosteroid treatment useful? A report of 8 cases and review of the literature.

Eight patients with endobronchial tuberculosis diagnosed on bronchoscopy were treated with antituberculosis drugs and a course of prednisone. The progress of the endobronchial lesions was assessed on repeated examinations. The course of the disease was variable and the endobronchial narrowing improved in two patients only. Hypersensitivity reactions associated with initiation of antituberculosis treatment may constitute a special group where corticosteroid is indicated. In other situations, the usefulness of corticosteroid for treatment of endobronchial tuberculosis is not well documented.

Adolescent↗
PubMed1990

Na(+)-H+ antiporter and Na(+)-(HCO3-)n symporter regulate intracellular pH in mouse medullary thick limbs of Henle.

To determine mechanisms of intracellular pH (pHi) regulation in mouse medullary thick limbs (MTAL), pHi was measured in MTAL suspensions and in the isolated perfused MTAL by use of 2',7'-bis(carboxyethyl)-5(6)carboxyfluorescein (BCECF). A method to obtain MTAL suspensions from the mouse outer medulla is reported. Characterization of suspensions with microscopy, anti-Tamm-Horsfall antibody labeling, measurement of O2 consumption, and adenosine 3',5'-cyclic monophosphate responses to antidiuretic hormone indicated that these suspensions were highly purified for viable MTAL tubules. The resting pHi was 7.41 +/- 0.02 (means +/- SE) in N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid-buffered media and 7.23 +/- 0.02 in CO2- HCO3(-)-buffered media, both at extracellular pH 7.4. MTAL tubules exhibited rapid pHi recovery from intracellular acidification. Recovery of pHi was dependent on luminal Na+ (apparent Km = 13.2 +/- 3.2 mM) and was inhibited by amiloride (apparent Ki = 10.6 microM), consistent with the activity of an apical Na(+)-H+ antiporter. Antiporter activity was enhanced by acidification and was diminished at the resting pHi. Recovery from intracellular alkalinization (rapid withdrawal of CO2- HCO3-) was sensitive to the stilbene anion transport inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, Cl(-)-insensitive, and Na(+)-sensitive, consistent with the activity of a Na(+)-(HCO3-)n symporter. Both transporters were significantly involved in steady-state pHi regulation in the presence of CO2- HCO3-. In contrast, the Na(+)-H+ antiporter played the dominant role in steady-state pHi regulation in the absence of CO2- HCO3-.

Animals↗
PubMed1990

A proposed clinical classification of pelvic endometriosis.

Two hundred and forty-four cases of pelvic endometriosis were diagnosed by laparoscopy between Jan. 1979 and Dec. 1986. Consulting the principles designated by the American Fertility Society (AFS) and Revised American Fertility Society (RAFS) classification, diseases were staged as mild, moderate and severe. The results of clinical classification were compared with those of laparoscopic classification. The conformance rate between clinical and RAFS classification was 74.2%. The pregnancy rates after operation were 69.2%, 42.9% and 38.5% among 94 patients clinically classified as mild, moderate and severe, respectively, as compared with 65.2%, 41.4% and 35.7% in terms of RAFS classification. The authors point out that laparoscopy is an excellent procedure for diagnosing and staging endometriosis. In hospitals where laparoscopic equipment is not available, clinical classification can be used as a substitute for staging those highly suspected of having endometriosis.

Endometriosis↗
PubMed1990

Surgical treatment for recurrent ovarian malignancies.

Eighty-nine cases of recurrent ovarian malignancies which had undergone surgical treatment were studied. Debulking surgery is of great value in the treatment of primary ovarian carcinoma, but for recurrent carcinomas success depends upon the pathological type. The 5-year survival rate was 75% for patients with immature teratomas, but only 6.1% for those with epithelial ovarian carcinomas and 3.6% with endodermal sinus tumors. Two cases of recurrent dysgerminoma were both alive and well more than 10 years after treatment. So repeated debulking is worthwhile for recurrent immature teratoma and dysgerminoma, while in cases of epithelial type or endodermal sinus tumors successful debulking surgery should be followed by some new kinds of adjuvant therapy, otherwise only failure will result.

Carcinoma↗
PubMed1989

Cell membranes impermeable to NH3.

Classically, there is a direct correlation between the lipophilic nature of a molecule and its rate of permeation across a biological membrane, so cell membranes should be more permeable to small, neutral molecules than they are to charged molecular species of similar size. Consequently, the distribution of NH+4 in biological systems is generally believed to be due to the rapid diffusion and equilibration of lipophilic NH3 across cell membranes and the accumulation of NH+4 to be governed by pH differences between compartments. Here we report that renal tubule cells from the medullary thick ascending limb of Henle have an apical membrane which is not only virtually impermeable to NH3, but is also highly permeable to NH+4. These remarkable properties have been incorporated into a model which explains how this renal epithelium can mediate vectorial movement of NH+4 between compartments of equal pH.

Ammonia↗
PubMed1989

Rapid hypertonic cell volume regulation in the perfused inner medullary collecting duct.

Differential interference contrast microscopic images were used to assess the cell volume regulatory increase (VRI) response of rat IMCD segments isolated from the mid-inner medullary region of pathogen-free Sprague-Dawley rats and perfused in vitro at 37 degrees C. In the absence of ADH. IMCD cells behaved in an osmometric fashion over the range of extracellular osmolalities 290 to 386 mOsm/kg H2O and had an osmotic space equal to 54.2% of total geometric volume. After initial shrinkage in hypertonic perfusing and bathing solutions (340 mOsm/kg H2O using sucrose), cell volume increased rapidly to the isotonic value only in tubules preincubated in ADH (100 microU/ml). The rates of VIR were: (-ADH) 0.0142 +/- 0.0046 nl.min-1.cm-1 or 0.30 +/- 0.10%/min and (+ADH) 0.7225 +/- 0.1278 nl.min-1.cm-1 or 15.42 +/- 2.31%/min (N = 4; P less than 0.01). An overshoot in cell volume was observed on return to isotonic media only in the ADH exposed tubules showing a hypertonic VRI response, indicating that IMCD cells accumulated solute during hypertonic VRI. In the absence of ADH, one mM dibutyryl cyclic AMP mimicked the effect of hormone on hypertonic VRI. This ADH-dependent VRI process required Na+ and (CO2 + HCO3-) in external media and was reduced or abolished by 0.1 mM amiloride, 0.1 mM 4,4'-diisothiocyanatostilbene-2,2-'-disulfonic acid (DIDS) in peritubular solutions. These data suggest that ADH-dependent, rapid hypertonic cell volume regulation in rat inner medullary collecting duct depends on NA+ uptake, which may be mediated by parallel Na+-H+ and an HCO3(-)-dependent. DIDS-sensitive pathway (such as, Cl+-HCO3- exchanger) in basolateral cell membrane. In addition, a luminal amiloride-sensitive pathway (most likely the cation-selective channel) may contribute to cell volume regulation in the rat IMCD.

Animals↗
PubMed1989

Anti-mucosal antibodies in recurrent aphthous ulcers.

Using indirect immunofluorescent antibody technique, anti-mucosal antibodies were evaluated in single or sequentially multiple sera from 21 patients with recurrent aphthous ulcers (RAU), 41 age/sex-matched healthy subjects, and 40 patients with miscellaneous oral mucosal diseases. Although anti-mucosal antibodies were found widely distributed in patients having oral mucosal diseases, there were significantly higher rates of positive anti-mucosal antibodies (15/21, 71%) and circulating intercellular substance (ICS) antibodies (14/21, 67%) in RAU patients as compared with either the healthy subjects or patients with miscellaneous oral mucosal diseases. Circulating ICS antibodies of IgG class were found to be significantly predominant in the active phase of 67% (14/21) RAU patients. The percentage decreased in the order of 25% (4/16) in the remission phase of one week, and to 10% (1/10) in the remission phase of two weeks. The presence of pemphigus-like antibodies might be elicited by the epidermal occult antigens released from damaged tissue and/or due to the transient immunoregulatory dysfunction caused by certain infectious agents.

Adolescent↗
PubMed1989

Luteal function in patients with endometriosis.

Nineteen patients with endometriosis were selected for investigation of luteal function as determined by serum progesterone (P) concentrations at different stages of the luteal phase, and by observation of basal body temperature (BBT) profiles and endometrial histological appearances. Sixteen cases were accompanied with infertility. All data were synchronized to the day of midcycle serum luteinizing hormone (LH) peak (D0) and analyzed accordingly. In the endometriosis group, mean serum P concentrations of early, mid luteal phases and the integrated P concentration of the whole luteal phase were significantly lower than in the control group. Five cases (26.3%) had low peak P values during mid-luteal phase and/or low integrated P levels. Delayed endometrial maturation was revealed in 10 of 16 cases (62.5%). Short luteal phase, as defined by BBT, was observed in 3 of 14 cases (21.4%). A total of 12 cases were screened for all three parameters, among them, ten (83.3%) had at least one abnormality and seven (58.3%) showed two aberrant results. In summary, the incidence of luteal phase defect was higher in the endometriosis group than in controls. The pathogenic mechanism of luteal phase defect and its role in infertility are discussed.

Adult↗
PubMed1988

Hypotonic cell volume regulation in mouse medullary thick ascending limb: effects of ADH.

Differential interference contrast microscopy was used in combination with standard electrophysiological techniques in the in vitro perfused mouse medullary thick ascending limb of Henle's loop (MAL) to evaluate the cell volume responses of this nephron segment during and following exposure to hypotonic media and to assess the role of antidiuretic hormone (ADH) and net salt absorption on the associated volume regulatory processes. Reductions in extracellular osmolality by 50 mosmol resulted in rapid increases in cell volume of approximately 20% with or without exposure to ADH. Cell volume recovery (volume-regulatory decrease, VRD) was much slower in the presence, than in the absence, of ADH. This hormone-mediated impairment of the VRD response could be overcome by the abolishment of net salt absorption with luminal 10(-4) M furosemide. An inverse linear relationship was observed between the rates of net salt absorption and VRD, indicating a finite ability of this nephron segment to enhance solute exit mechanisms whether induced by increases in transcellular traffic or by hypotonic cell swelling. Finally, returning to the isotonic media resulted in cell shrinkage under all conditions [+/- ADH and +(ADH and furosemide)] consistent with cell solute loss mediating VRD. However, recovery of cell volume back to the initial isotonic control value [post-VRD volume regulatory increase (VRI)] was only observed in ADH-treated tubules and was independent of net salt absorption. The post-VRD VRI response could be abolished by isohydric CO2-HCO3- removal or by addition of 10(-4) M amiloride to the peritubular medium. The latter results suggest that parallel Na+-H+ and Cl- -HCO3- exchangers located in basolateral membranes mediate the post-VRD VRI response.

Absorption↗
PubMed1987

Lack of effect of beta-endorphin on basal or glucagon-stimulated hepatic glucose production in vitro.

beta-Endorphin appears to have effects on hepatic glucose production in vivo. In order to determine whether beta-endorphin modulates glucose production directly, the effects of beta-endorphin on isolated rat hepatocytes were investigated. This permitted isolation of the effects of beta-endorphin from hormonal and/or neuronal influences. A significant dose-related stimulatory effect of glucagon (10(-10) to 10(-6) mol/L) on both hepatic glucose production and glycogen phosphorylase a activity was demonstrated. No effect of either physiologic (10(-11) to 10(-9) mol/L) or supraphysiologic (10(-6) mol/L) concentrations of beta-endorphin on these parameters, under basal or glucagon-stimulated conditions, could be detected. These results suggest that reported in vivo effects of beta-endorphin to inhibit hepatic glucose production were either indirect or centrally mediated.

Animals↗
PubMed1987

Lymphocyte function in patients with recurrent aphthous ulcers.

Lymphocyte proliferation (LP) responses to mitogens: phytohemagglutinin (PHA), concanavalin A (ConA) and pokeweed mitogens (PWM) were studied in 17 patients with recurrent aphthous ulcers (RAU) of minor type (MiAU) and 20 age/sex-matched healthy subjects. RAU patients elicited normal T-cell and B-cell responses to mitogens in comparison with healthy subjects. Proliferative responses were neither enhanced during active episodes of oral ulceration nor suppressed during periods of remission. It seems unlikely that non-specific lymphocyte dysfunction plays a major role in the pathogenesis of RAU.

Adult↗