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Biomedical subjects

D Powell

Publications and source records attributed to D Powell.

At least 109 records · Page 6Linked to original sources
PubMed1985

Broviac catheter sepsis: the natural history of an iatrogenic infection.

Between January 1982 and December 1983, 335 Broviac catheters placed in 270 infants and children were prospectively evaluated. The average duration of catheter life was 99.7 days, yielding a total accumulated experience of 33,394 catheter days. Blood culture-proven bacteremia occurred on 77 occasions (23%), an average of one spetic episode for every 434 days of catheter use. Temperature elevation was the only consistent clinical sign of infection occurring in 91% of the children. White blood cell counts remained within the normal range in the majority of patients. The differential counts were most helpful, however, documenting a significant increase in the number of immature neutrophils. The rise in band forms was frequently observed 24 to 48 hours before the onset of clinically evident sepsis. Platelet counts did not change significantly. Eighty-eight microorganisms were identified on blood culture. Eighty-three bacterial isolates were recovered (94%) and five fungi. The vast majority of patients (86%) had a single organism on blood culture but polymicrobial sepsis was observed on 11 occasions. Staphylococcus sp (38%) and Streptococcus sp (25%) species were most common. Of particular importance, 48% of coagulase negative staphylococci were nafcillin-resistant. Of the gram negative bacteria, Klebsiella (10%) and Pseudomonas (6%) species were most frequent. In 53 patients, antibiotic therapy was administered in an attempt to salvage the catheter. Bacteremia was controlled successfully in 39 (74%), and in the other 14 children, persistent sepsis dictated catheter removal. One patient (0.4%) died as a result of catheter-related sepsis.

Catheterization↗
PubMed1985

Immunoreactive substance P and LH-RH content in median eminence and pituitary gland during proestrus, oestrus, lactation and after anterior hypothalamic deafferentation.

Substance P (SP) and luteinizing hormone releasing hormone (LH-RH) content were measured by radioimmunoassay in median eminence of female rats, SP only in rats pituitary after decapitation on the day of oestrus (E), on the first and second day of dioestrus (D1 and D2), on the day of proestrus (P) and in "constant oestrus" (AD) caused by anterior hypothalamic deafferentation and in lactation (L). During four days of oestrus cycle the highest SP and LH-RH content of median eminence was found in dioestrus. Both during cyclic oestrus and "constant oestrus", SP and LH-RH were significantly lower than on the second day of dioestrus. These results may suggest the reciprocal functional relation of both hypothalamic peptides in the mechanism of the control of gonadotropin release. The highest LH-RH concentration of the median eminence was found in the animals on the 11th to 15th day of lactation, while the SP content in the median eminence of these animals is not significantly different from those of the remaining groups except the value for dioestrus (D2) rats. The SP content in pituitary of lactating rats was significantly higher than those of rats during cyclic or "constant oestrus".

Animals↗
PubMed1985

Differential expression of the mouse cholecystokinin gene during brain and gut development.

Cholecystokinin (CCK) is a neuropeptide found in brain and intestine. In this report, we have isolated a cDNA clone that encodes CCK from a mouse brain cDNA library. This cDNA clone has extensive homology to CCK precursors that have been sequenced previously. Southern blots of genomic DNA probed with this cDNA clone revealed single bands for each of eight different restriction enzymes, all of which could be accounted for by a single genomic clone, suggesting that the CCK gene is present as a single-copy gene in mice. RNA blots, primer extensions, and S1 nuclease protection assays have suggested that the same RNA start site is utilized in brain and in gut. Finally, we have shown, by using RNA blots and a radioimmunoassay specific for CCK, that CCK is expressed at maximum adult levels in intestine at birth but that adult concentrations of CCK and its mRNA are not reached in brain until much later in development.

Animals↗
PubMed1985

The management of patients in a phobia clinic.

Management of people in this phobia clinic is based on a theory that phobias result from misinterpretations of the effects of a natural process that generates fear in responses to imagined dangers as in a nightmare. With support, guidance, exposure, and information, phobic people learn in individual and group settings to confront, control, and understand their phobic experience.

Adaptation, Psychological↗
PubMed1984

Regulation of synthesis of the larval serum proteins of Drosophila melanogaster.

We have determined the relative amounts of subunits of larval serum proteins (LSPs) 1 and 2 during larval development in Drosophila melanogaster. These results indicate that synthesis of polypeptide subunits of LSP-1 and LSP-2 is coordinate: the proteins are first detected at the same time; they accumulate in a coordinate fashion; their RNAs are first detected at the same time; the RNAs also accumulate in similar relative amounts. Analyses of fat body polypeptides and fat body RNA indicate that synthesis of LSP-1 declines at a time when there are still substantial quantities of LSP-1 RNA in the cytoplasm. Cessation of LSP-1 subunit synthesis occurs before cessation of LSP-2 synthesis, indicating that at late times the genes (or mRNAs) for these two proteins are subject to different "switch-off" controls.

Adipose Tissue↗
PubMed1984

Pedigree study of familial Alzheimer disease.

Twenty-one families with familial Alzheimer disease were ascertained in a dementia clinic and assessed by multiple family interviews. Eight autopsies were reviewed. The age of onset varied from 25 to 85. Seven pedigrees showed evidence of 3 generation transmission. Paternal age of the founders of 4 lines which could be assessed was higher than controls.

Adult↗
PubMed1983

Platelet associated IgG and immune thrombocytopenia in lymphoproliferative and autoimmune disorders.

Thrombocytopenia is frequently encountered in patients with lymphoproliferative disorders (LPD) and systemic erythromatosus (SLE) and to a lesser extent in association with other diseases such as rheumatoid arthritis (RA), pernicious anaemia (PA) and autoimmune haemolytic anaemia (AIHA). This report attempts to document the incidence of thrombocytopenia in these disorders, other than that overtly due to malignant infiltration or marrow suppression by drugs and to demonstrate, that in a significant proportion antibody mediated immune destruction of platelets can be confirmed by positive platelet antibody tests. Platelet associated IgG (PAIgG) was measured in all patients by a quantitative enzyme linked assay. Platelet antibodies were found in 11 of 24 (46%) thrombocytopenic patients with LPD, 10 of 16 (62%) patients with SLE and thrombocytopenia, and in all patients with RA and PA who had low platelet counts at the time of study. In addition, elevated PAIgG levels were found in the following non-thrombocytopenic patients: 9 of 43 (21%) patients with LPD, 2 of 12 (17%) with SLE, 2 of 12 (17%) with AIHA, 2 of 39 (5%) with PA and 5 of 61 (8%) patients with RA. The nature and the role of raised PAIgG levels in diseases other than autoimmune thrombocytopenia is controversial. Our reasons for interpreting these as true platelet autoantibodies in this selected group of disorders and the clinical implications of our results are discussed.

Anemia, Hemolytic, Autoimmune↗
PubMed1983

A rat model for chemotherapy-induced male infertility.

The effects of chronic administration of cyclophosphamide and procarbazine on testicular function in the rat were examined. Cyclophosphamide produced disruption of the normal spermatogenic architecture that was dose and time dependent. Total ablation of the germinal epithelium was not achieved. Procarbazine produced more specific testicular damage. Multiple weekly injections of 100-200 mg/kg of procarbazine caused complete destruction of the spermatogenic cells, with no effect on Sertoli cells. Treated animals remained infertile for more than 4 months and showed no histologic evidence of recovery. This model may be useful for examining possible mechanisms to prevent spermatogenic damage associated with cancer chemotherapy in man.

Animals↗
PubMed1983

Hemoperfusion in a child who ingested diquat and died from pontine infarction and hemorrhage.

A 2 1/2 year old boy accidentally ingested the herbicide diquat. Progressive neurologic dysfunction preceded his death 143 hours after poisoning. Brain stem infarction and purpura were noted at post mortem and closely resembled the brain stem pathology in 3 of 7 adults who died after diquat ingestion. Renal, gastrointestinal and pulmonary involvement in this child also resembled that seen in adults after ingestion of diquat. Hemoperfusion was performed six times in an effort to lower the body diquat burden. Cellulose-coated, activated charcoal was first employed 40 hours postingestion and removed diquat from serum with clearances of 104 and 39 ml/minute at the initiation of hemoperfusion and 6 hours later, respectively. Serum diquat concentrations decreased rapidly during charcoal hemoperfusion. However, marked rebound in serum diquat concentrations were noted between charcoal treatments, indicating extensive sequestration of diquat by tissues. Thrombocytopenia and hypocalcemia, the major complications of charcoal hemoperfusion, were easily treated. Unlike charcoal, Amberlite XAD-4 resin hemoperfusion did not remove diquat from serum. Charcoal hemoperfusion may temporarily reduce serum diquat concentrations. Whether the early institution and daily performance of charcoal hemoperfusion will minimize diquat-induced damage to brain and other organs is not clear from this case and will only be determined in future studies.

Adolescent↗
PubMed1983

Substance P in obstetrics and gynecology.

The occurrence and distribution of the neurohormone substance P in the urogenital tract suggest a role for substance P in regulation of blood flow, smooth-muscle activity, and sensation. The distribution and pharmacologic effects of substance P in the brain suggest an involvement of substance P in regulating the release of gonadotropins and prolactin from the pituitary and in the gonadal-hypothalamic feedback. As substance P is also present in endocrine-like cells of the diffuse endocrine system in the urogenital tract, it may serve as a tumor marker for carcinoid and related tumors, particularly in the ovary and the uterine cervix. This review is limited to the distribution and effects of substance P in the female genital tract and its relevance in female reproduction.

Animals↗
PubMed1982

Continuous ambulatory peritoneal dialysis in children: comparison with hemodialysis.

The clinical and biochemical effects of continuous ambulatory peritoneal dialysis in 20 children and of hemodialysis in 16 children were compared over a 2 1/2-year period. Statistically significant differences between the treatment groups included higher hematocrit, higher serum carbon dioxide and cholesterol levels, large intake of calories and protein, and lower systolic blood pressure and rates of transfusion in the patients receiving continuous ambulatory peritoneal dialysis. These patients had more complications than the patients receiving hemodialysis, but hospitalization rates in the two groups were similar. The cost of continuous ambulatory peritoneal dialysis was +19,600 per patient-year; the cost of hemodialysis was +54,300 per patient-year; the cost of hemodialysis was +54,300 per patient-year. There were four treatment failures with continuous ambulatory peritoneal dialysis and one with hemodialysis. Patients treated with both forms of dialysis preferred continuous ambulatory peritoneal dialysis. We conclude that continuous ambulatory peritoneal dialysis is an important alternative to hemodialysis in children.

Blood Pressure↗
PubMed1982

Tumor regression and histologic clearance after neutron brachytherapy for bulky localized cervical carcinoma.

The response of bulky, advanced Stage 1B and early Stage II carcinoma of the cervix to neutron brachytherapy (NT and radiotherapy) was studied using combined NT radiation and extrafascial hysterectomy with histologic evaluation. Scheduling of neutron therapy relative to external beam photon therapy, tumor volume, tumor stage, tumor histology, and clinical tumor clearance were assessed in these studied. NT was easily combined with surgery in this study. Low stage tumors, small tumor volume and "early" neutron implants (scheduled within +/- one week of the start of fractionated radiation) showed more frequent histologic clearance of tumor. Long-term tumor control has been achieved and failures developed distance metastases without pelvic or local recurrence. This experience indicates that NT was effective for tumor clearance and control and represents and promising new modality for localized, advanced tumor therapy.

Adult↗