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Biomedical subjects

F Dorey

Publications and source records attributed to F Dorey.

At least 91 records · Page 5Linked to original sources

Deep sepsis following total knee arthroplasty. Ten-year experience at the University of California at Los Angeles Medical Center.

Between September 1971 and May 1982, at the University of California at Los Angeles Medical Center, 821 total knee arthroplasties were performed in 604 patients, all of whom received perioperative antibiotics. Deep sepsis, proved by a positive culture of a specimen obtained by postoperative arthrocentesis, developed fourteen times in thirteen knees of twelve patients, an incidence of 1.71 per cent. In one of these patients, who had systemic lupus erythematosus and bilateral knee replacement, the right knee became infected with two distinct organisms on two different occasions (separated by ten months). The first infection was probably hematogenous while the second, developing after a dental procedure, definitely was. Over-all, five infections were hematogenous with an identified source and one other was suspected of having a hematogenous origin. The time from operation to the diagnosis of sepsis averaged 8.3 months over-all, but five of the fourteen infections were recognized less than two months after arthroplasty. For the six infections that were assumed to be hematogenous, the time from operation to the diagnosis of sepsis averaged 16.4 months. The major presenting symptom was pain in thirteen of the fourteen infections. The initial treatments of the fourteen infections consisted of intravenous antibiotics in all of them, primary removal of the prosthesis and so-called exchange arthroplasty after five days in one, removal of the prosthesis and fusion in one, arthrotomy and débridement in six, arthroscopic irrigation in three, and antibiotics alone in three (of which one was treated with an exchange arthroplasty after three weeks). At last follow-up, only four of the thirteen prostheses had been salvaged.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗

Retinal hemorrhage in retinopathy of prematurity associated with tocopherol treatment.

Two hundred eighty-seven infants were enrolled in a double masked, randomized, placebo controlled trial of early parenteral tocopherol given from day one. Among the 232 survivors with ophthalmologic follow-up, retinal hemorrhages occurred more frequently in the tocopherol group (16/111; 14.4%) than in the placebo group (8/121; 6.6%). The development of retinal hemorrhages correlated strongly with plasma tocopherol levels from three weeks to three months (P less than 0.05). Future studies of tocopherol should be aware of potential bleeding diatheses, and study this prospectively.

Cerebral Hemorrhage↗

The use of three baseline values in intervention studies: application to evaluation of immune modulation therapies.

In studying the effects of a treatment intervention on immunological parameters, we have found that three baseline values are a practical number to obtain on each patient. Three baseline values 1) increase the chances of detecting a statistically significant effect of the intervention, 2) provide an assessment of the daily variability of the assay and patients, and 3) enable the identification of individual patients who demonstrate significant changes associated with the intervention.

Drug Evaluation↗

Amiloride potentiation of differentiation of human promyelocytic cell line HL-60.

Cells of the human acute promyelocytic cell line HL-60 undergo differentiation when exposed to dimethyl sulfoxide (DMSO); in this report, amiloride, an inhibitor of passive intracellular Na+ flux, potentiated the DMSO-induced differentiation of HL-60 cells. This effect was seen at several concentrations of DMSO. Amiloride alone did not affect HL-60 differentiation. Various analogues of amiloride were tested for their ability to potentiate differentiation of HL-60 cells. The synergistic induction of myeloid differentiation by a membrane solvent (DMSO) and an Na+ transport inhibitor (amiloride) suggested membrane cation flux as being important in initiating differentiation.

Amiloride↗

The effect of plasma glucose variability on neonatal outcome in the pregnant diabetic patient.

Maternal glucose variability was studied in 154 pregnant diabetic patients hospitalized during the last month of their pregnancies. By means of several statistical analyses of the coefficient of variation for within-day plasma glucose variability, we found as follows. (1) There was a significant association between maternal glucose variability and neonatal outcome. (2) Patients with greater glucose variability had more episodes of hyperglycemia, but not hypoglycemia. (3) There was no correlation between maternal glucose variability and the birth weight of the infant. We are proposing the use of an index for glucose variability to monitor glucose control in pregnancy and predict neonatal outcome. Although absence of glucose variability will not ensure prevention of neonatal complications, there is a clear association between greater glucose variability and neonatal complications.

Birth Weight↗

Isoelectric focusing of human anti-diphtheria toxoid antibodies: identical spectrotypes of anti-fragment A antibodies with the same IgG subclass and light chain constant regions are expressed in multiple individuals.

The serum antibodies from humans booster-immunized with diphtheria toxoid were analyzed by isoelectric focusing. To restrict the antibody response, we visualized those antibodies that reacted to the Fragment A moiety of diphtheria toxin. Of the 100 normal human donors examined, 20 were estimated to be nonresponders to Fragment A. Sixty-three of the 80 donors who responded to Fragment A had restricted IgG-anti-Fragment A spectrotypes that consisted of three to eight distinct bands. Six series of repeat or shared spectrotypes were delineated among our donor population with repeat frequencies ranging from 0.025 to 0.312. We determined that the repeat spectrotypes were IgG1-kappa anti-Fragment A antibodies. Three percent of our donors had complex IgG-anti Fragment A spectrotypes consisting of greater than 10 bands. In some instances, the complex spectrotypes were composed of simple spectrotypes found among other donors. The complex IgG-anti Fragment A spectrotypes of these donors consisted of both IgG1 and IgG4-anti-Fragment A antibodies. From a statistical analysis, we calculate that only a limited number of IgG-anti-Fragment A spectrotypes are expressed in vivo after booster immunization. Our analysis suggests two groups of IgG-anti-Fragment A spectrotypes exist in our donor population. One IgG-anti-Fragment A spectrotype group is expressed randomly, and a second group is preferentially expressed among individuals in our donor population.

Antibodies, Bacterial↗

Suppression of natural killer cell cytotoxicity in the peripheral blood of patients receiving interferon therapy.

Lymphoblast interferon (IFN-alpha) was administered to patients with advanced stages of cancer in a phase I drug toxicity trial. IFN-alpha was given i.m. twice daily at 12-h intervals over a 7-day course of therapy in dosages ranging from 1.5 to 100 X 10(6) U/day. A total of 28 patients was studied, including 9 with breast carcinoma, 11 with other solid tumors, and 8 with lymphoid malignancies. Immune cell parameters were determined for each patient before, during, and up to 20 days after therapy. Leukopenia was evident after 1-2 days of IFN-alpha administration, became maximal after 6-7 days of therapy, and then returned to baseline values by day 13 post-therapy. Circulating natural killer (NK) cell activity was found to increase significantly by 2 h after the initial IFN injection, especially in patients receiving the higher dosages. However, most subjects demonstrated a return to baseline NK levels at 24 h despite the continued presence of elevated serum concentrations of IFN. By day 7 of therapy, NK-cell function was markedly depressed. Following cessation of IFN, NK levels rapidly returned to pretherapy baseline values. Changes in K-cell cytotoxic function (ADCC) tended to parallel those of NK-cell function. Although NK/K-cell function was affected by IFN therapy, no change in the percentage of circulating Fc receptor-bearing cells was found. This indicates that the cytotoxic cells were probably present in the circulation, but were not able to express their lytic function.

Blood Cells↗

Comparison of i. m. diazepam and hydroxyzine as premedicants.

The effectiveness of diazepam as premedication when administered by two different i.m. techniques was compared with hydroxyzine in 84 male and 101 female patients. Variables studied were relief of anxiety, sedation, acceptance by both patient and anaesthetist and pain at the injection site. Diazepam 20 mg in male and diazepam 10 mg in female patients administered by a Z-track injection technique were as effective premedicants as hydroxyzine 100mg i.m. In men diazepam was good as hydroxyzine regardless of the injection technique. In women the technique of injection of the diazepam was critical to achieving good results. The Z-track injection method decreased the amount of severe pain on injection in both sexes to levels similar to those achieved with hydroxyzine.

Adolescent↗

The use of an ROC curve to express quality of care results.

When a quality of care method which results in a continuous score is viewed as a screening device, it is possible to evaluate the efficiency and effectiveness of the score using assessment techniques usually applied to screening tests for disease. Using an independent standard (such as patient outcome) for determining which records truly represent inadequate medical care, for any quality score cutoff we can calculate the sensitivity and the specificity of the screening device for identifying inadequate care. An ROC curve allows the user of a screening test to select a threshold that takes into account both the estimated prevalence of inadequate care at the site and the relative importance placed on false positive and false negative errors. We used an ROC curve to examine the performance of criteria mapping, a chart review system. The criteria map method was employed to evaluate the disposition decision for 421 patients who came to 2 emergency departments with complaints of chest pain. The shape of the ROC curve generated from these data allows the user to evaluate the effect of choosing various cutpoints, acknowledging explicitly the tradeoffs between failure to review cases of inappropriate disposition and needless review of appropriate disposition.

Emergency Service, Hospital↗

Systemic administration of human leukocyte interferon to melanoma patients. I. Effects on natural killer function and cell population.

Natural killer (NK) cytotoxicity was assessed against K562 targets in 14 melanoma patients who received daily im doses of human leukocyte interferon (IFN) for 42 consecutive days. The most common pattern of NK activity was a decline from pretreatment levels 1 day after initiation of treatment, followed by increasing cytotoxicity with peak activity at day 7 and a subsequent gradual decline to pretreatment levels during the remaining weeks of treatment. This pattern was particularly apparent in patients who received 3 x 10(6) or 9 x 10(6) U IFN/day, while patients who received 1 X 10(6) U IFN/day tended to lack the decline at day 1 and maintained the elevated NK activity past day 7. Changes in NK activity could not be related to changes in absolute lymphocyte counts; to proportions of cells bearing membrane receptors for erythrocyte-antibody-complement, of cells bearing FC gamma receptor; or to clinical response to IFN.

Cytotoxicity, Immunologic↗

Activation of human NKCC by moderate exercise: increased frequency of NK cells with enhanced capability of effector--target lytic interactions.

In the present study we examined the mechanism of human natural killer cellular cytotoxicity (NKCC) augmentation by 5 min of moderate exercise and its interrelationship to in vitro interferon (IFN) activation. Cytotoxicity was measured by employing both a single-cell cytotoxic assay and a standard 3-hr chromium-51 (51Cr) release assay. The former was used to assess changes at the single NK cell--target cell level and the latter to assess changes in overall lytic capacity of a given population of NK cells. Several findings were obtained: (1) moderate exercise augmented NKCC in vivo by recruiting a 'new' population of active cytotoxic NK cells. (2) This 'new' population of active cells probably was derived from cells which can bind targets but are non-cytotoxic. (3) In a standard 51Cr-release assay, additional augmentation of these exercise-activated cells occurred in vitro following exposure to interferon. (4) This additional increase in cytotoxicity produced no alteration in the frequency of killer cells as viewed at the single cell level. (5) Thus interferon's capacity to increase further the overall lytic ability of exercise-activated NK cells was not due to its activation of an additional subset of pre-NK cells, but due to its increasing the capacity of effector--target lytic interactions (recycling) of the same set of NK and pre-NK cells.

Cytotoxicity, Immunologic↗

Depression of the generation of cell-mediated cytotoxicity by macrophage-like suppressor cells in bladder carcinoma patients.

Depressed T-lymphocyte function as assessed by delayed-type hypersensitivity reactions and in vitro proliferative response to mitogens is a characteristic finding in many types of solid tumors, including bladder carcinoma. Peripheral blood leukocytes from 16 patients with transitional cell carcinoma of the bladder were compared with age-matched, control subjects. Both the unfractionated leukocytes containing 10 to 30% monocytes and the lymphocyte-enriched preparations, obtained by monocyte depletion with iron filing ingestion, were analyzed. Mixed leukocyte culture-induced cytotoxicity was depressed in the patient group; the amount of depression was directly correlated to the extent of the disease. In patients who underwent surgical removal of tumor, the mixed leukocyte culture-induced cytotoxicity appeared normal. This mixed leukocyte culture-generated cytotoxic response was a more sensitive indicator of tumor effect than was the induced proliferative response. Removal of phagocytic or adherent monocytes from the responding cell population caused a significant increase in the generated cytotoxicity, especially in those patients with invasive disease. These suppressive effects could be partially reconstituted by quantitative addition of the separated monocytes back to the responding lymphocyte culture. The depressed lymphocyte-mediated cytotoxicity present in these bladder cancer patients was due, in a major part, to a circulating macrophage-like cell with active suppressor function.

Carcinoma, Transitional Cell↗

Comparison of immune derangements in patients with different malignancies.

Immune function was evaluated in 109 patients with carcinoma of the breast, bladder, head and neck, and lung. Patients with head and neck cancer showed the most profound derangements of immune function; patients with lung cancer showed no detectable abnormalities. Non-irradiated patients with disseminated head and neck cancer had significantly depressed lymphocyte counts (mean 1357/mm3, P less than .05), E-rosette forming cells (mean 770/mm3, P less than .05), and response to phytohemagglutinin (P less than .05) as compared to controls. This immunodeficiency was detected in patients with localized as well as advanced disease. Although significant differences were noted between patients with head and neck cancer and the other tumors, these differences were minimized by radiation therapy. All irradiated patients showed comparable degrees of immune dysfunction. Absolute Fc-receptor cells were depressed in all irradiated patients and in non-irradiated patients with disseminated breast cancer.

Adult↗

Interferon activation of "pre-spontaneous killer" (pre-SK) cells and alteration in kinetics of lysis of both "pre-SK" and active SK cells.

Interferon augments spontaneous killer cellular cytotoxicity (SKCC). This modulation may be vital in both tumor resistance and host viral defenses. To date, whether increased numbers of effector cells or activation of individual effector cells is responsible for this augmentation has not been established. Using a single cell assay where SK killing is directly visualized by the reading of trypan blue uptake at various time points by effector-target cell conjugates plated in agarose gel, we measured in vitro alterations in percentage of conjugate formation, number of active SK cells, and kinetics of SK cell lysis at the single cell level after 1 hr of interferon incubation. After interferon, there is no difference in number of cells that bind K-562 targets. This augmentation of cytotoxicity is due to both recruitment of new effector cells and an activation of the lytic process of both the new and already active SK cells.

Analysis of Variance↗