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Biomedical subjects

F Thomas

Publications and source records attributed to F Thomas.

At least 289 records · Page 16Linked to original sources
PubMed1984

Pulmonary artery catheter occlusion as an indication of pulmonary embolus.

Two patients with respiratory failure had consistently reproducible findings on insertion of flow directed pulmonary artery catheters which led to the subsequent diagnosis of pulmonary embolus. Occlusion of the catheter tip and development of a rising "overwedge" tracing on deflation of the balloon may mean the catheter tip has become embedded in clot. When combined with the inability to obtain a wedge tracing, the deflation "overwedge" tracing should alert the physician to the possibility of unsuspected pulmonary embolus.

Aged↗
PubMed1984

CT detection of occult pneumothorax in head trauma.

A prospective evaluation for occult pneumothorax was performed in 25 consecutive patients with serious head trauma by combining a limited chest CT examination with the emergency head CT examination. Of 21 pneumothoraces present in 15 patients, 11 (52%) were found only by chest CT and were not identified clinically or by supine chest radiograph. Because of pending therapeutic measures, chest tubes were placed in nine of the 11 occult pneumothoraces, regardless of the volume. Chest CT proved itself as the most sensitive method for detection of occult pneumothorax, permitting early chest tube placement to prevent transition to a tension pneumothorax during subsequent mechanical ventilation or emergency surgery under general anesthesia.

Craniocerebral Trauma↗
PubMed1984

The influence of in situ repair systems on survival of several irradiated parenchymal cell types.

Radiation survival curves are presented for several normal parenchymal cell types irradiated in situ or in vitro. The data presented indicate that the in situ survival parameters for a specific cell type cannot be simply extrapolated from the results of either in vitro assays or rapid in vivo clonal transplantation assays. The data suggest that the D0 and terminal slope of in vitro survival curves can reflect those parameters for cells left in situ, but the shoulder width and the n value cannot. This appears to be due to the inability of the in vitro environment to support two major forms of repair that occur in situ, i.e. the "contact effect" and in situ repair (ISR). ISR is a form of potentially lethal damage repair (PLDR) that occurs when certain cells are allowed to remain in situ following irradiation. ISR is characterized by an increased shoulder in the survival curve without a change in slope and it has been observed in rat mammary, thyroid and liver epithelia.

Adolescent↗
PubMed1983

Characteristics of the acquired immunodeficiency syndrome (AIDS) in Haiti.

To identify the characteristics of the acquired immunodeficiency syndrome (AIDS) as it occurs in Haiti, we studied 61 previously healthy Haitians who had diagnoses of either Kaposi's sarcoma (15), opportunistic infections (45), or both (1) established in Haiti between June 1979 and October 1982. The first cases of Kaposi's sarcoma and opportunistic infections in Haiti were recognized in 1978-1979, a period that coincides with the earliest reports of AIDS in the United States. We do not believe that AIDS existed in Haiti before this period. The types of opportunistic infections and the clinical course in Haitians with Kaposi's sarcoma and opportunistic infections were similar in most aspects to those in patients with AIDS in the United States. The median age of Haitians with Kaposi's sarcoma and opportunistic infections was 32 years, and 85 per cent were men. The interval between diagnosis and death was six months in 80 per cent of the patients. Diarrhea was the most common reason for seeking medical attention in patients with opportunistic infections. Lymphopenia and skin-test anergy were observed in 86 and 100 per cent of patients, respectively. Potential risk factors (bisexual activity or blood transfusions) were identified in 17 per cent of male and 22 per cent of female patients. Demographic information suggests that patients belonged to all socioeconomic strata of Haitian society.

Acquired Immunodeficiency Syndrome↗
PubMed1983

The risk of infection related to radial vs femoral sites for arterial catheterization.

To evaluate risk factors for infections associated with indwelling arterial catheters, 186 catheters were randomly allocated for either femoral or radial insertion in 155 critically ill patients. Femoral catheters were easier to insert and it was easier to obtain blood specimens from them. Rates of local infection at the insertion sites and rates of positive catheter-tip cultures were similar for femoral and radial catheters. Evidence of local infection was not predictive of a positive catheter-tip culture. Percutaneously inserted femoral and radial artery catheters had a similarly low incidence of catheter-associated infections. There was only one catheter-related infection, and no cultured catheter was judged the cause of bacteremia. Routine prophylactic replacement of arterial catheter systems may be unnecessary in critical care units where rates of arterial catheter-associated infections are low.

Adult↗
PubMed1982

Correlation between postmortem ethanol levels in the blood and the testicle. A computerized study of 633 determinations.

This study emphasizes the value of the presence of ethanol in the testicle. It proves particularly useful in cases where blood and urine are no more present in the body. In 633 cases where blood or urine were still available, a highly positive correlation between the blood, alcohol and the amount of alcohol present in the testicle could be demonstrated, thus confirming the research carried out in the Department of Legal Medicine as far back as 1943. An attempt is further made to assess the possible influence of such factors as putrefaction, submersion or post-traumatic anemia on this correlation.

Cadaver↗
PubMed1982

Evidence for the repair of potentially lethal damage in irradiated bone marrow.

The effects on cell survival of maintaining bone marrow cells (CFU-S) in situ following irradiation and before assay by transplantation was investigated. When the CFU-S cells are maintained in situ following irradiation survival drops and plateaus at about 9 h post-irradiation. Evidence is presented that this decrease in survival may be due to potentially lethal damage repair (PLD) inhibition caused by post-irradiation in situ holding. This effect on PLD repair is different than that usually found in cells in vitro and in vivo tumors in that it mainly alters the shoulder rather than the slope of the survival curve of CFU-S cells. It is different than PLDR found in vivo for normal mammary and thyroid gland epithelial cells because in situ holding decreases rather than increases the survival of CFU-S cells. Evidence is also presented that the radiation survival curve for in situ bone marrow cells (CFU-S) may not have a shoulder.

Animals↗
PubMed1982

Differential effects of intravenous anaesthetic agents on cell-mediated immunity in the Rhesus monkey.

Considerable evidence has accumulated to implicate general anaesthetic agents as a cause of post-surgical immune depression. In the present study we evaluated the immuno-suppressive effects of three in vivo administered anaesthetic agents on cellular immune function in sub-human primates which did not undergo surgery. Normal rhesus monkeys received a minimal anesthetic dose of ketamine HCl, meperidine HCl, or sodium pentobarbital. Peripheral blood mononuclear cells were assayed for mitogen-induced lymphocyte proliferative responses and cell-mediated cytotoxicity (CC), including antibody-dependent CC, spontaneous CC and alloimmune CC. In vivo administration of the three agents caused significant reduction in lymphocyte functional capabilities. Within 30 min after administration of ketamine HCl or sodium pentobarbital, cytotoxic effector function was significantly depressed, with variable recovery occurring at 48 hr; cytolytic effector function was not impaired after meperidine HCl or in untreated controls. Ketamine HCl selectively suppressed effector function; mitogen-induced lymphocyte proliferative responses were not suppressed. Monkeys given meperidine HCl showed stable effector function and depressed lymphocyte proliferative function. Effects from sodium pentobarbital were non-selective, with reduced cytotoxic and proliferative lymphocyte functions. In summary, this study shows that intravenous anaesthetic agents are immunosuppressive in primates and exhibit disparate effects on afferent and efferent expressions of cellular immunity.

Anesthetics↗
PubMed1979

Effect of rabbit anti-human thymocyte globulin on lymphocyte subpopulations and functions following allotransplantation in the rhesus monkey.

The survival time of skin allografts from RhLA-nonidentical, unrelated donors was increased from a mean of 7.69 days in controls (n = 20) to a mean of 32.53 days in rhesus monkeys (n = 21) receiving a total dose of 250 mg of rabbit anti-human thymocyte globulin (RATG) per kg. Immunological monitoring studies were performed on the peripheral blood of mononuclear cells in control and treated monkeys. After administration of RATG, the percentage of E rosette-forming cells (E-RFC) was greater than 90% depressed, and the percentage of EAC rosette-forming cells was increased 5-fold in the circulation. Significant numbers of RATG-coated cells were detected only during the first week after RATG treatment. The percentage of E-RFC recovered to pretreatment levels within 3 to 4 weeks after RATG treatment, although the absolute E-RFC count remained depressed for 2 to 3 months. In addition, the in vitro proliferative responsiveness to polyclonal mitogens and to allogeneic lymphocytes remained greater than 80% depressed for 2 to 3 months after RATG treatment. The incidence of post-transplant-specific antidonor lymphocyte-mediated cytotoxicity (LMC) was similar in controls (85%) and RATG-treated monkeys (81%), and the appearance of LMC was correlated (r = 0.711) with partial recovery of absolute ERFC counts in the treated group. The appearance and peak of LMC were delayed (P less than 0.001) in RATG-treated monkeys, but preceded and correlated with rejection. Prior to rejection, the serum of RATG-treated monkeys inhibited LMC. Antibody-dependent cellular cytotoxicity appeared after rejection in the majority of recipients in both groups. The appearance and peak of antibody-dependent cell-mediated cytotoxicity (ADCC) were delayed (P less than than 0.001) in RATG-treated monkeys, but did not exhibit a significant correlation with the time of rejection.

Animals↗
PubMed1979

Macrophage-related suppressor cells in human renal transplant recipients.

In this study 66 renal transplant recipients were studied by in vitro immunologic monitoring assays in an attempt to delineate some immune reactivity parameters which migh explain the successful long-term survival of HLA incompatible allografts. Ninety percent of the recipients were found to be responsive to their specific donors in one-way mixed lymphocyte culture assays, indicating the presence of antigen reactive proliferating T cells. In contrast, studies of the in vitro generation of cytotoxic T cells showed that 73% of the long-term recipients demonstrated a marked hyporesponsiveness to the donor in cell-mediated lympholysis (CML) assays. Longitudinal studies indicated that specific CML hyporesponsiveness to the donor developed after transplantion. In the majority of recipients, CML hyporesponsiveness could be related to a suppressor cell phenomenon, since recipient mononuculear cells specifically suppressed the CML reactivity of third-party cells to the donor. Recipient CML hyporesponsiveness to the donor could be abrogated by removal of recipient adherent cells, most of which were monocytes or macrophages. The suppressor cell effect on CML is postulated to be related to macrophages which are either acting independently or under the regulation of suppressor T cells. These studies are among the first to suggest that suppressor cell regulation of relevant effector T cell activity may be important in the facilitation of successful human renal transplantation.

Cell Adhesion↗