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Biomedical subjects

D Huang

Publications and source records attributed to D Huang.

At least 235 records · Page 13Linked to original sources
PubMed1993

Diet and ethanol modulate immune responses in young C57BL/6 mice.

Chronic ethanol (ETOH) ingestion adversely affects the immunocompetence of alcohol abusers. ETOH directly impairs host defense mechanisms and indirectly modulates immunocompetence by interfering with the nutritional status of the alcoholic. It is not clear from the current literature, however, to what extent ETOH, nutritional status, or the combination of the two factors modulates immune mechanisms in chronic alcoholics. To date, most animal studies investigating the immunotoxicity of ETOH have neglected the dietary factors, which may have masked additional immunotoxic effects of ETOH. To examine these dietary factors, we fed mice three liquid ETOH diets with different dietary sufficiencies for 7 weeks and investigated various immune responses. Spleen cell number and secretions of immunoreactive interleukin-2 and tumor necrosis factor were totally independent of the diet, being affected only by ETOH. Body, spleen, and thymus weights, interferon-gamma secretion, and natural killer cell and phagocytic activities were modulated by ETOH as well as by diet. Natural killer cell and phagocytic activities were also directly affected by the nutritional quality of the diet. These results suggest that animal diets used in experimental studies of ETOH-induced immunomodulation must be planned and controlled carefully in order to single out the direct effects that ETOH has on the host defense system.

Alcoholism↗
PubMed1993

[The usefulness of serum antibody to Epstein-Barr virus-specific DNAase (EDAb) in early detection of nasopharyngeal carcinoma].

During a mass screening of nasopharyngeal carcinoma (NPC) in Guangzhou area, 224 out of 5030 normal individuals were found to be EDAb positive (anti-enzyme rate > or = 30%). Seventy seven of the 224 gave high antibody titter (anti-enzyme rate > 50%). After a 52-month follow-up, 14 NPC patients were picked up. All but one were from EDAb positive individuals and 9 patients were from those with high antibody titter. The relative risks of developing NPC were 279 and 562 for EDAb positive individuals and for those with high antibody titter, respectively. On the outpatient department, 98 patients with negative biopsy of the nasopharynx for cancer were divided into EDAb positive (n = 44) and negative (n = 54) groups. Within 3-month follow up, 39 NPC were diagnosed by multiple biopsies. 34 cases were from the first group (77.3%) while only 5 from the second group (9.3%). The occurrence rate of NPC in the first group was 8.3 fold as high as that in the second group. The results of the present studies indicate that EDAb assay is useful for early detection of NPC.

Adult↗
PubMed1993

Cataract: a critical problem in the developing world.

Cataract blindness is a major public health problem worldwide. Unlike other leading causes of blindness, cataract can be treated effectively with surgery. Demographic, social, and economic factors are important determinants of surgical treatment of this disorder in the developing world, resulting in the accumulation of very large numbers of unoperated cases. Because of many factors, the problem is really out of hand. In this paper, we try to raise awareness among optometrists of this major challenge. At the same time, because many individuals do not achieve good vision after surgery and because in most developing countries only one eye is operated upon, we emphasize the use of improved prognostic techniques to make the surgical outcome more predictable, avoiding nonproductive surgery and resultant disappointment on the part of all concerned. We feel optometry can play important roles in diagnosis, visual correction, and management of these patients, hopefully in cooperation with ophthalmic surgeons.

Blindness↗
PubMed1993

Laparoscopic trocar-assisted colpotomy.

Trocar-assisted transvaginal colpotomy was performed in 17 patients to remove large pathologic specimens during laparoscopic operations when the specimen could not be extirpated through the laparoscopic ports. Under direct laparoscopic visualization, colpotomy was performed using a 10- or 11-mm disposable trocar without the sleeve. The trocar was removed, a ring forceps was placed through the incision, the incision was enlarged, and the mass was grasped with the ring forceps and removed. This technique is safe, fast, and easy to perform. In addition, smoke is not created and potential electrocautery damage to pelvic structures is avoided.

Female↗
PubMed1992

Hepatitis B virus DNA integration and expression of an erb B-like gene in human hepatocellular carcinoma.

Southern blot studies on Hepatitis B Virus (HBV) DNA integration in 13 human hepatocellular carcinomas (HCCs) patients revealed the presence of several distinct HBV integration sites in different human liver disease patients. In one HCC patient the DNA fragment containing the HBV integration also hybridized to an erb B probe. The erb B/HBV co-migrating DNA fragment was cloned and sequenced, and showed that HBV DNA is integrated next to a cellular DNA fragment which is homologous to the tyrosine protein kinase domain of the human epidermal growth factor receptor gene and other cell surface receptor genes. The virus-integrated cellular DNA sequence is expressed in this HCC patient, suggesting a possible role for this gene in hepatocarcinogenesis.

Adult↗
PubMed1992

Immunosuppression induced by nitric oxide and its inhibition by interleukin-4.

Mice immunized with attenuated Salmonella typhimurium, strain SL3235, while protected against virulent challenge, are unable to mount in vivo and in vitro antibody responses to non-Salmonella antigens, such as tetanus toxoid and sheep red blood cells, and exhibit profoundly suppressed responses to B and T cell mitogens. Suppression of antibody responses is mediated by macrophage (M phi)-released soluble factors, and is completely reversed by treatment with interleukin (IL)-4. The present report identifies the suppressor factor as nitric oxide (NO), and provides evidence for a mechanism by which IL-4 abrogates suppression. Suppressed antibody responses correlated with high levels of NO secretion by splenocytes of SL3235-immunized mice. NO production was observed only in cultures consisting of the adherent cell fraction of immune splenocytes. Further, immunosuppression was reversed by NG-monomethyl-L-arginine (NMLA), a competitive inhibitor of NO synthesis, and was completely blocked by the addition of excess L-arginine. Treatment with IL-4, or anti-interferon (IFN)-gamma monoclonal antibody (mAb), also abrogated suppression. Optimal reversal of suppression was observed only when NMLA, IL-4, or anti-IFN-gamma mAb, was added at day 0 of the 5-day plaque-forming cell assay. Treatment with either IL-4 or anti-IFN-gamma mAb also lead to a sharp inhibition of NO production by immune spleen cells. Moreover, the addition of IL-4 to splenic adherent M phi inhibited their ability to generate NO. Our data characterize an immunoregulatory pathway, involving IFN-gamma and NO, by which M phi mediate immunosuppression and identify IL-4 as a potent inhibitor of this pathway.

Animals↗
PubMed1992

Exercise-induced hypoxemia in athletes: role of inadequate hyperventilation.

These experiments examined the exercise-induced changes in pulmonary gas exchange in elite endurance athletes and tested the hypothesis that an inadequate hyperventilatory response might explain the large intersubject variability in arterial partial pressure of oxygen (PaO2) during heavy exercise in this population. Twelve highly trained endurance cyclists [maximum oxygen consumption (VO2max) range = 65-77 ml.kg-1.min-1] performed a normoxic graded exercise test on a cycle ergometer to VO2max at sea level. During incremental exercise at VO2max, 5 of the 12 subjects had ideal alveolar to arterial PO2 gradients (PA-aO2) of above 5 kPa (range 5-5.7) and a decline from resting PaO2 (delta PaO2) 2.4 kPa or above (range 2.4-2.7). In contrast, 4 subjects had a maximal exercise PA-aO2 of 4.0-4.3 kPa with delta PaO2 of 0.4-1.3 kPa while the remaining 3 subjects had PA-aO2 of 4.3-5 kPa with delta PaO2 between 1.7 and 2.0 kPa. The correlation between PAO2 and PaO2 at VO2max was 0.17. Further, the correlation between the ratio of ventilation to oxygen consumption vs PaO2 and arterial partial pressure of carbon dioxide vs PaO2 at VO2max was 0.17 and 0.34, respectively. These experiments demonstrate that heavy exercise results in significantly compromised pulmonary gas exchange in approximately 40% of the elite endurance athletes studied. These data do not support the hypothesis that the principal mechanism to explain this gas exchange failure is an inadequate hyperventilatory response.

Adult↗
PubMed1992

Cardiac rehabilitation participation predicts lower rehospitalization costs.

The effect of participation in cardiac rehabilitation on medical costs was determined by measuring hospitalization charges for cardiac admissions over a 3-year period in 580 post-coronary event patients (58% after coronary bypass surgery, 42% after myocardial infarction), of whom 230 entered a cardiac rehabilitation program and 350 did not. Baseline left ventricular ejection fraction was similar in entrants and nonentrants (59.9% vs 59.5%). Over the 1 to 46-month follow-up period (mean 21 months), per capita hospitalization charges for participants in cardiac rehabilitation were $739 lower than charges for nonparticipants ($1197 +/- 3911 vs $1936 +/- 5459, p = 0.022). This was due to both a lower incidence of hospitalizations and lower charges per hospitalization. Inasmuch as groups differed with regard to age, sex, diagnostic category, and smoking status, data were adjusted for these baseline differences by means of analysis of covariance. Rehospitalization charges remained significantly higher in nonparticipants (p = 0.015). Because physician charges were not measured, the cost differential between groups is underestimated. Results of this study show an association between participation in comprehensive cardiac rehabilitation and lowered cardiac rehospitalization costs in the years after an acute coronary event.

Aged↗
PubMed1992

Incompletely resected advanced squamous cell carcinoma of the head and neck: the effectiveness of adjuvant vs. salvage radiotherapy.

Between 1982 and 1988, 441 patients were treated at the Medical College of Virginia for AJC Stage III and IV squamous cell carcinoma of the head and neck. We report here on 84 patients whose tumors were incompletely resected based on histopathological margins of 1 mm or less. Of these 84 patients, 49 were treated with surgery alone and 35 received immediate postoperative irradiation to doses of 50-70 Gy. The two patient groups are comparable with respect to stage of disease, age, male/female and racial ratios. This retrospective analysis, based on follow-up of 24-110 months, gives actuarial locoregional tumor control and survival data. The local control and disease-free survival rates in the combined modality group are significantly superior at the p = 0.0006 and p = 0.0003 levels, respectively, relative to the group treated with surgery alone. Patients in the combined modality group also experienced a significantly improved adjusted and overall survival, p = 0.005 and p = 0.01, respectively. The administration of postoperative irradiation was not associated with an increased rate of complications. The benefit of radiotherapy on survival was only seen when given as postoperative treatment but was lost in patients treated for salvage after tumor recurrence.

Adult↗
PubMed1992

Effects of anti-TNF monoclonal antibody infusion in patients with hairy cell leukaemia.

Tumour necrosis factor (TNF) can act as an autocrine growth factor for hairy cell leukaemia (HCL) cells. The TNF produced by the malignant clone may also inhibit normal haematopoiesis thereby contributing to the cytopenias observed in patients with the disease. We have studied the effects of infusing a murine monoclonal anti-TNF antibody in three patients with HCL. In two patients receiving 0.5 mg of antibody/kg on alternate days for 12 d, the drug was well tolerated. The third patient received 2 mg/kg on alternate days and developed symptoms of serum sickness by day 9. In two patients with severe B-lymphocytopenia, circulating CD19 and CD20 positive, B-cells were restored to normal, the majority of which were negative for the HCL-associated marker CD11c. B-lymphocyte recovery was associated with a rise in serum immunoreactive IL-6 and with an early rise in immunoreactive TNF. These short courses of anti-TNF MAb treatment had modest effect on the tumour burden, producing a reduction in splenomegaly in one patient. Exploration of the effects of more prolonged administration of higher dose anti-TNF antibody will only be feasible when less immunogenic MAbs are available.

Animals↗
PubMed1992

Validity of pulse oximetry during exercise in elite endurance athletes.

Eleven highly trained male cyclists [maximal aerobic power (VO2max) = 70.6 +/- 4.2 ml.kg-1.min-1] performed both high intensity constant load (90-95% VO2max) and incremental cycle exercise tests with arterial blood sampling to evaluate the accuracy of pulse oximeter estimates (%SpO2) of arterial oxyhemoglobin fraction of total hemoglobin (%HbO2). Three subjects also performed an incremental exercise test in hypoxic conditions (inspired partial pressure of O2 = 89, 93, or 100 Torr). Arterial %HbO2 was determined via CO-oximetry and ranged from 72 to 99%. Three Ohmeda 3740 pulse oximeters were used to estimate %HbO2, one on each ear lobe and a finger probe. The finger probe tended to provide the best estimate of %HbO2 during exercise: the mean %SpO2 - %HbO2 difference for 232 exercise observations was 0.52 +/- 1.36% (SD). Finger probe %SpO2 and %HbO2 were highly correlated [r = 0.98, standard error of the estimate (SEE) = 1.32%, P less than 0.0001]. The accuracy of pulse oximeters has been questioned during high-intensity exercise. When aerobic power was greater than 81% of VO2max (n = 75), the finger probe's mean error was -0.01 +/- 1.40%. Finger probe %SpO2 and %HbO2 were highly correlated (r = 0.97, SEE = 1.32%, P less than 0.0001). These results indicate that this pulse oximeter is a valid predictor of %HbO2 in elite athletes during cycle exercise.

Adult↗
PubMed1992

[Anti-inflammatory and analgesic actions of artificial and fermentative Ganoderma sinense (AFGS)].

Both AFGS and natural Ganoderma sinense (NGS) have obvious anti-inflammatory and analgesic effects for arthritis in rats induced by carrageenan and the pain reaction in mice induced by hot scalding as well as HAC-induced writhing. AFGS also can reduce the edematous swelling of mice's ears, reduce the capillary permeability of mice skin and obviously inhibit cotton pellets granuloma implanted in rats. It can promote cytophagy capacity of the reticular endothelial cells in mice. No irritation on the gastric mucosa in rats has been observed.

Animals↗