Biomedical subjects

D S Chi

Publications and source records attributed to D S Chi.

78 records · Page 5Linked to original sources

PubMedDate not supplied

Hematological and immunological acute mental stress responses of people who are severely and profoundly mentally retarded.

Relocation stress may be one factor increasing the mortality rate of people who are severely and profoundly retarded (S/P MR) when they transfer from institutional to community living arrangements. However, no research exists concerning acute stress effects with groups who are S/P MR. In this project, 28 residents of a state facility for those with S/P MR were exposed to five-minute structured educational tasks. Venous blood samples were drawn before and after the stressor. Granulocytes, red blood cells, hemoglobin, and plasma protein increased while monocytes decreased after stress. Immune cell subsets did not change significantly. Hemoconcentration, an important factor in thrombosis and ischemia, may relate to relocation stress in S/P MR populations. Methodological factors limit generalization but additional research with larger samples, more indices of stress, more poststress blood samples, and additional stressors are encouraged.

Acute Disease↗

PubMedDate not supplied

Effects of stress and blood type on cortisol and VLDL toxicity preventing activity.

Past research has associated ABO blood type and mental stress with cardiovascular risk. We studied the effects of blood type (A vs. O) coupled with a mirror drawing stressor on very low density lipoprotein toxicity-preventing activity (TxPA) and plasma cortisol levels. Exposure to the stressor significantly decreased TxPA and increased cortisol for the total group of 25 older adult males. However, the stress response patterns of the 15 blood type A males were different from those of the 10 type O subjects. The blood type A group had higher initial levels of TxPA and cortisol as well as quicker stress recovery rates than the type O group. ABO blood type may be an important behavioral hematologic variable to assess in studies concerning biochemical stress response or cardiovascular risk.

ABO Blood-Group System↗

PubMedDate not supplied

The cardiovascular and metabolic complications of HIV infection.

With the advent of more effective therapies for human immunodeficiency virus (HIV) infection, HIV-infected patients are living longer and cardiovascular disease is becoming more obvious in this population. Patients with HIV infection represent one of the most rapidly developing groups with cardiovascular disease globally. Cardiovascular disease complicating HIV infection is likely to contribute to burgeoning healthcare costs. Pericarditis, myocarditis, cardiomyopathy, atherosclerotic coronary vasculopathy, arterial aneurysms, pulmonary hypertension, and endocarditis occur with increased frequency in these patients. Pericardial tamponade, dilated cardiomyopathy, endocarditis, and vasculopathy can lead to fatal outcomes in this population. The advent of cardiomyopathy heralds a very poor prognosis in patients infected with HIV. Coronary vasculopathy without obvious risk factors can lead to myocardial ischemia in young patients infected with the virus. Moreover, the protease inhibitors used to treat HIV infection induce a syndrome of lipodystrophy and dyslipidemia that may be associated with accelerated atherosclerosis as well as insulin resistance. All these factors contribute to increased cardiovascular morbidity and mortality in the HIV-infected population. HIV infection, opportunistic infections, secreted viral proteins such as gp120 (envelope protein) or Tat (transactivator of viral transcription), and cytokines elaborated during the course of HIV infection of the immune system all contribute to pathogenesis of these disorders. Further basic and clinical studies are required to understand the pathogenesis of cardiovascular complications and develop appropriate management strategies for these patients.

Anti-HIV Agents↗

PubMedDate not supplied

Phase II study of tirapazamine plus cisplatin in patients with advanced or recurrent cervical cancer.

The aim of this study was to evaluate the activity and toxicity of a tirapazamine (TPZ)/cisplatin drug combination in patients with stage IV or recurrent cervical cancer. The chemotherapy was administered for a maximum of eight cycles every 21 days. TPZ was administered intravenously at 330 mg/m(2) over a 2-h infusion, followed 1 h later by cisplatin intravenously at 75 mg/m(2) over 1 h on day 1. All patients received antiemetics including dexamethasone, ondansetron, and lorazepam. Subsequent doses were unchanged, reduced, or omitted according to observed toxicity and protocol guidelines. Response evaluation was performed every two cycles. Thirty-six patients with stage IV or recurrent cervical cancer were treated. Ninety-four percent of patients had prior radiotherapy. Two patients had prior chemotherapy. There were two complete responses and eight partial responses (27.8%). An additional 11 patients (30.6%) had stable disease as their best response. Response rate was greater in tumors outside of the previously radiated field (44.4% vs 11.1%). The median time to progression was 32.7 weeks. The most frequent grade 3 or 4 adverse events were nausea, vomiting, and fatigue, which occurred in 30.6%, 25%, and 22% of subjects, respectively. Anemia was the most frequent grade 3 or 4 hematologic toxicity at 8.3%. We conclude that the combination of cisplatin and TPZ was reasonably well tolerated in patients with recurrent or advanced cervical cancer. Further evaluation of this drug combination may be warranted.

Adult↗

PubMedDate not supplied

Inhibition of a chicken B-cell lymphoma by suppressor T-cells from agammaglobulinemic chickens.

The growth of B-cell lymphoma, LSCC-RP9, in culture was inhibited by spleen cells from bursa-immunized agammaglobulinemic (A-gamma) chickens. This inhibition was mediated by suppressor T-cells. The growth of transplantable LSCT-RP6 B-cell lymphoma was suppressed in A-gamma chickens, while that of the control SPCT-RP11 T-cell tumor was not affected. Furthermore, the incidence and growth of the LSCT-RP6 tumor in normal recipients were decreased when it was co-transplanted with spleen cells from bursa immunized A-gamma chickens. The results suggest that suppressor T-cells inhibit the growth of B-cell lymphoma.

Agammaglobulinemia↗

PubMedDate not supplied

Differential effects of streptozotocin and streptozotocin-induced diabetes mellitus on tumor metastases and growth in mice.

Diabetic mouse serum was found to be toxic to F-10 melanoma cells in vitro. However, when F-10 cells were injected intravenously into streptozotocin-induced diabetic mice there was a significant increase in the number of lung tumors. Contrarily, when streptozotocin was injected after F-10 cells there was a 5-fold decrease in lung metastases. Reversal of the diabetes in these mice by nicotinamide or insulin injection did not increase the lung metastases. Solid tumors (resulting from the subcutaneous injection of F-10 cells) grew at similar rates in both control and diabetic mice. Streptozotocin injected after F-10 cells resulted in a 6 day delay in the appearance of solid tumors. Triglycerides, the toxic factors in vitro, were elevated to similar extents in both tumor-bearing control and diabetic mice. Most of the differences in tumor growth between control and streptozotocin injected mice were attributable to the antitumor activity of streptozotocin, rather than the diabetic state.

Animals↗