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Biomedical subjects

A Porter

Publications and source records attributed to A Porter.

At least 37 records · Page 2Linked to original sources
PubMed1997

Personal and situational factors that predict coping strategies for acute stress among basketball referees.

The aim of this study was to establish the ways in which coping style and situational appraisals are related to the consistency of using approach and avoidance coping strategies for skilled Australian basketball referees (n = 133) after three game-related stressful events. The events, 'making a mistake', 'aggressive reactions by coaches or players' and 'presence of important others', were determined from previous research on sources of acute stress among basketball officials. Our findings indicated that: referees exhibited consistent avoidance, but not approach, coping styles; they used more avoidance than approach strategies; and they perceived stress to be positively correlated with approach, and negatively associated with avoidance, coping strategies. These findings suggest that individual differences exist in perceptions of stress (i.e. situational appraisals), controllability and coping styles among moderately and highly skilled basketball referees. The implications for teaching cognitive and behavioural strategies for effective coping with acute stress in basketball officiating are discussed.

Adaptation, Psychological↗
PubMed1997

Phase III trial of androgen suppression using goserelin in unfavorable-prognosis carcinoma of the prostate treated with definitive radiotherapy: report of Radiation Therapy Oncology Group Protocol 85-31.

PURPOSE: Although androgen suppression results in a tumor response/remission in the majority of patients with carcinoma of the prostate, its potential value as an adjuvant has not been substantiated. MATERIALS AND METHODS: In 1987, the Radiation Therapy Oncology Group (RTOG) initiated a randomized phase III trial of adjuvant goserelin in definitively irradiated patients with carcinoma of the prostate. A total of 977 patients had been accessioned to the study. Of these, 945 remained analyzable: 477 on the adjuvant arm and 468 on the observation arm. RESULTS: Actuarial projections show that at 5 years, 84% of patients on the adjuvant goserelin arm and 71% on the observation arm remain without evidence of local recurrence (P < .0001). The corresponding figures for freedom from distant metastases and disease-free survival are 83% versus 70% (P < .001) and 60% and 44% (P < .0001). If prostate-specific antigen (PSA) level greater than 1.5 ng is included as a failure (after > or = 1 year), the 5-year disease-free survival rate on the adjuvant goserelin arm is 53% versus 20% on the observation arm (P < .0001). The 5-year survival rate (for the entire population) is 75% on the adjuvant arm versus 71% on the observation arm (P = .52). However, in patients with centrally reviewed tumors with a Gleason score of 8 to 10, the difference in actuarial 5-year survival (66% on the adjuvant goserelin arm v 55% on the observation arm) reaches statistical significance (P = .03). CONCLUSION: Application of androgen suppression as an adjuvant to definitive radiotherapy has been associated with a highly significant improvement in local control and freedom from disease progression. At this point, with a median follow-up time of 4.5 years, a significant improvement in survival has been observed only in patients with centrally reviewed tumors with a Gleason score of 8 to 10.

Adenocarcinoma↗
PubMed1996

Conformal mixed neutron and photon irradiation in localized and locally advanced prostate cancer: preliminary estimates of the therapeutic ratio.

PURPOSE: To determine the incidence of chronic toxicity and the probability of biochemical and histologic complete response among patients with nonmetastatic prostate cancer, treated with three dimensional (3D) conformal mixed neutron and photon irradiation. METHODS AND MATERIALS: Between November 1991 and December 1994, 151 patients with prostate cancer were entered in three prospective dose-finding studies of conformal mixed neutron and photon irradiation. Patients with low stage, low to intermediate grade prostate cancer (T1-2NXM0, Gleason Score < or = 7) received 38 Photon Gy (PhGy) plus 9 (51 patients) or 10 (53 patients) Neutron Gy (NGy) to the prostate and seminal vesicles. Forty-seven patients with locally advanced prostate cancer (T3-4 N0-1 M0 and/or Gleason Score > or = 8) received 15 NGy + 18 PhGy to the prostate and seminal vesicles and 9 NGy + 18 PhGy to the pelvic lymph nodes. RESULTS: The median follow-up was 16 months (range: 3-30 months). There was no Grade 3-5 GI or GU toxicity recorded. At 20 months, the actuarial rates of Grade 2 GI morbidity were 6 and 29% for the 9-10 and 15 NGy protocols, respectively (p = 0.07). At 20 months, the incidences of Grade 2 GU morbidity were 4 and 16%, respectively (p = 0.08). Stiffness in flexing or abducting the hips was seen in 20 and 42% of patients receiving 9-10 and 15 NGy, respectively (p = 0.01). Potency was maintained in 65% of all patients. Among patients with an initial PSA < or = 10, 100% had a 12-month PSA < 2 and 78% < 1 ng/ml. Negative postradiation biopsies were seen in 30% of patients 6 months, 79% at 12 months, and 84% of patients at 18 months. CONCLUSION: The use of conformal mixed neutron and photon irradiation has been well tolerated with no severe bladder or rectal complications observed. However, because of the enhanced toxicity seen with 15 NGy, the current maximum dose levels of neutron irradiation have been limited to 11 NGy.

Adenocarcinoma↗
PubMed1996

Influence of diabetes mellitus and glycaemic control on the characteristics and outcome of common infections.

The aim of the present study was to elucidate the effect of diabetes and metabolic control on the presentation, sources, pathogens and outcome of common infections. Of 515 patients admitted to three departments of internal medicine because of a suspected acute infection, 132 (26%) had diabetes mellitus. Osteomyelitis was diagnosed in 3% of the diabetic patients and in 1% of patients without diabetes, and infection of the extremities in 7% and 0%, respectively (p = 0.003). Klebsiella sp. caused 24% of urinary tract infections in diabetic patients, versus 13% in patients without diabetes (p = 0.1). The percentage of Staphylococcus aureus infections in diabetic patients was 10% versus 5% in non-diabetic patients (p = 0.06). The gross mortality rate in the diabetic patients was 10%, and in patients without diabetes, 12%. In patients without fatal underlying disorders, mortality in the diabetic patients was 10% (2% in patients with glycosylated haemoglobin (GHb) lower than median, and 17% in patients with GHb higher than median) and in the non-diabetic patients 4% (p = 0.04). Five factors were independently and significantly related to mortality in diabetic patients: acute respiratory distress (very large odds-ratio [OR]), coma (OR 3.8, 95% confidence interval [CI] 1.0-14.3), GHb above the median (OR 3.3, 95% CI 1.8-6.2), the interaction between GHb and absence of a severe underlying disorder (OR 12.0, 95% CI 2.9-50.7) and duration of diabetes (OR of 1.072 for 1-year increment, and 1.42 for a 5-year increment). Choice of empiric antibiotic treatment in diabetic patients with suspected bacterial infection should take into account the preponderance of Klebsiella sp. and Staphylococcus aureus infections. The present results favour an association between poor glycaemic control and a fatal outcome of infectious diseases in diabetic patients.

Aged↗
PubMed1996

Multifractionated high-dose-rate brachytherapy with concomitant daily teletherapy for cervical cancer.

BACKGROUND: High-dose-rate (HDR) brachytherapy has been the preferred treatment for cervical cancer at Wayne State University since 1987. The outcome of the first 105 patients treated is analyzed. PURPOSE: To determine clinical efficacy of the HDR modality. METHODS: We reviewed 105 patients and evaluated the 88 patients treated for cervical carcinoma with HDR and external beam radiotherapy (EBRT) from August 1987 to December 1992. Patients received initial external radiation to the pelvis (total dose of 19.8 to 39.6 Gy in 11 to 22 fractions), followed by outpatient HDR brachytherapy (3 fractions/week, 386 cGy/fraction to Point A, total of 8 to 12 fractions) and concurrent daily EBRT (1.8 to 2.0 Gy) to lateral parametria. During the HDR period of treatment, step wedge transmission blocks were used to shield central pelvic tissue while treating peripheral pelvic tissues with EBRT. Patient distributions were as follows: 25, IB/IIA; 35, IIB/IIIA; and 28, IIIB/IVA. There were 56 African American and 32 Caucasian patients with mean age of 55 (range 19-89). The median follow-up was 33 months (range 20 to 76 months). Kaplan-Meier analysis was performed. RESULTS: Three-year survival rates were 88%, IB/IIA; 69%, IIB/IIIA; 56%, IIIB/IVA; and 72% overall. Local control was achieved in 71/88 (80%) of patients. Failure site was cervix or within the pelvis in 12 patients, distant metastasis only 17 patients, and combined local and distant in 5 patients. Of the failures, 82% (28/34) died within 2 years. There were 3 grade III/complications (3.4%). CONCLUSION: Results compare favorably with previous LDR experience.

Adult↗
PubMed1996

Two rules for early prediction of bacteremia: testing in a university and a community hospital.

BACKGROUND: Two rules (model 1 and model 2) were previously derived and prospectively validated at the same institution to predict the likelihood of bacteremia. The objective of the present study was to test and compare the performance of the rules in patients admitted to two sites of inpatient care: a university hospital and a community hospital. METHODS: Clinical and laboratory data (including the variables contained in the two models) were collected within 24 hours in all patients admitted to the Department of Medicine of the Beilinson Medical Center, a university hospital in central Israel, and Emek Hospital, a community hospital in northern Israel, because of an acute infectious disease. The scores of the models were compared with the results of blood cultures. RESULTS: The percentage of bacteremia was 15% in the university and 18.5% in the community hospital. The area under the receiver-operating characteristic curve was 0.56 + or - 0.04 SE for model 1, and 0.67 + or - 0.04 SE for model 2 in the university hospital; and 0.59 + or - 0.05 SE versus 0.63 + or - 0.04 SE, respectively, in the community hospital. At the best calibration, model 1 defined low-risk groups of 205 patients in the university hospital, and 66 patients in the community hospital, with prevalences of bacteremia of 13% and 15%. The high-risk groups defined by model 1 had prevalences of 30% and 32%. Model 2 defined low-risk groups with prevalences of bacteremia of 7% (8 of 114) and 8% (6 of 76); and high-risk groups with percentages of 29% and 38%. CONCLUSIONS: The overall accuracy of the two models deteriorated significantly. Both models defined groups at high risk of bacteremia, but the percentages of bacteremia and of death in the low-risk groups do not encourage withholding blood cultures in these patients. The failure of the two models points toward the need for external validation, and for monitoring performance of prediction models over time.

Adolescent↗
PubMed1995

12(S)-HETE is a mitogenic factor for microvascular endothelial cells: its potential role in angiogenesis.

12(S)-HETE [12(S)-hydroxyeicosatetraenoic acid] is a lipoxygenase metabolite of arachidonic acid. Treatment of murine-lung-derived microvascular endothelial cells (CD clone 4) with exogenous 12(S)-HETE promoted wound healing of injured endothelial cell monolayers. 12(S)-HETE, in a time- and dose-dependent manner, enhanced the growth of CD clone 4 cells. Thymidine incorporation assays demonstrated that 12(S)-HETE increased the DNA synthesis by > 4 fold. In addition, normal endothelial cell growth stimulated by serum could be dose-dependently inhibited by a select 12-lipoxygenase inhibitor (BHPP), suggesting that 12(S)-HETE is a physiological mitogenic factor for microvascular endothelial cells.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1995

Quality-adjusted survival analysis of malignant glioma. Patients treated with twice-daily radiation (RT) and carmustine: a report of Radiation Therapy Oncology Group (RTOG) 83-02.

PURPOSE: To quantify the quality of life of malignant glioma patients treated on a randomized Phase I/II trial of twice-daily radiation therapy (RT) and carmustine, using a modified quality adjusted survival (QAS) model, and to compare the QAS among assigned treatment arms. MATERIALS AND METHODS: The Radiation Therapy Oncology Group (RTOG) accrued 786 malignant glioma patients to a Phase I/II randomized dose escalation trial of twice-daily RT with carmustine from 1983 to 1989. Patients were randomized to one of four arms of hyperfractionated RT in 1.2 Gy twice daily (BID) fractions (64.8 Gy, 72.0 Gy, 76.8 Gy, or 81.6 Gy) or to either of two accelerated hyperfractionated RT arms in 1.6 Gy BID fractions (48.0 or 54.4 Gy). Although preliminary toxicity and survival data have been published, little information is available regarding the quality of these patients' lives during and following such therapy. QAS is a refinement of the methodology for assessing survival quality among breast cancer patients receiving adjuvant chemotherapy. The QAS method allows for inclusion of both improvement and decline in neurologic functional status. Patients were scored by the presence or absence of 15 neurologic signs and symptoms at on-study and at every follow-up. Within each category were gradations of severity, with the quality survival time (Q-TIME) adjusted according to any changes in these neurologic findings. The summation of all changes in signs and symptoms were weighted by 1/15th and incorporated into the QAS model as QAS = Q-TIME-TOX-RRX. TOX was the time spent with treatment-related toxicities, and RRX was the time spent in recovery from subsequent therapy. RESULTS: Of 747 evaluable patients, the average QAS time was 18.5 months. The average QAS for the hyperfractionated arms of 64.8 Gy, 72.0 Gy, 76.8 Gy, and 81.6 Gy were 15.6, 20.8, 10.0, and 13.7 months, respectively. For the accelerated hyperfractionated RT arms of 48.0 and 54.4 Gy, the average QAS times were 13.1 and 13.4 months. The QAS time of the 72.0 Gy arm was significantly longer than that of all other groups, except the 64.8 Gy arm. As expected, the QAS times were strongly discriminated by both age and Karnofsky Performance Scores (KPS) (p < 0.001). Younger patients and patients with high KPS benefited most from assignment to the 72.0 Gy arm; QAS time was not significantly longer in any treatment arm among patients over age 50 or with KPS scores of 80 or less. CONCLUSIONS: This quality-adjusted survival methodology can be successfully applied to malignant glioma patients and permits a quantitative assessment of the influence of investigational therapies on patient quality of life. This analysis confirms the potential benefit of intermediate dose (72.0 Gy) hyperfractionated RT for selected malignant glioma patients.

Adult↗
PubMed1995

Survey of brachytherapy practice in the United States: a report of the Clinical Research Committee of the American Endocurietherapy Society.

PURPOSE: To obtain reliable data on the extent of the brachytherapy practice in the United States by conducting a comprehensive survey of all facilities. METHODS AND MATERIALS: The Clinical Research Committee of the AES surveyed all 1321 radiation oncology facilities identified in the Patterns of Care Study (PCS) of the American College of Radiology (ACR). Multiple mailings and follow-up were made to obtain a high response rate. Survey responders and nonresponders were compared using chi-square tests. Summary statistics were reported. RESULTS: Of the 1321 facilities, 1054 responded (80%). Hospital-based and larger facilities had a statistically significant higher rate of response. Brachytherapy was being performed at 819 facilities (the median number of procedures = 21-50). Two hundred and two facilities did no brachytherapy. The common isotopes used were 137Cs (705 facilities), 192Ir (585 facilities), 125I (236 facilities), and 131I (194 facilities). The common brachytherapy techniques used were intracavitary (751 facilities), interstitial (536 facilities), intraluminal (310 facilities), and plaques (148 facilities). Remote afterloaded brachytherapy was used at 205 centers as follows: high dose rate (HDR) (164), medium dose rate (MDR) (5), and low dose rate (LDR) (36). Computerized dosimetry was most commonly used (790 facilities), followed by Patterson-Parker (104 facilities) and Quimby (72 facilities). The common sites treated were cervix (701 facilities), endometrium (565 facilities), head and neck (354 facilities), and lung (344 facilities). CONCLUSION: Data regarding brachytherapy practice has been obtained from a large percentage (80%) of all facilities in the United States. The majority (78-81%) of radiation oncology facilities perform brachytherapy; however, its use is restricted to gynecological implants in many of these centers. The results from this survey will be used to develop a pattern of care study and data registry in brachytherapy.

Brachytherapy↗
PubMed1995

Functional discrepancies between tumor necrosis factor and lymphotoxin alpha explained by trimer stability and distinct receptor interactions.

Tumor necrosis factor (TNF) and lymphotoxin alpha (LT alpha) are closely related cytokines which bind with nearly identical affinities to the same pair of cell surface receptors, p55 and p75TNFR. Therefore it is assumed that TNF and LT alpha are redundant cytokines. This study, however, demonstrates that TNF and LT alpha differ significantly with regard to their mitogenic and cytotoxic potentials. LT alpha's superior mitogenic effect could be explained by its formation of a more stable trimer. In contrast to the TNF trimer, which disintegrated under physiological conditions into biologically inactive monomers, the LT alpha trimer remained stable for several days. Accordingly, LT alpha more effectively induced fibroblast growth which demands long-term presence of the cytokine. TNF's superior cytotoxicity, which requires only short-term impact of the cytokine, could be attributed to a distinct interaction with the human p55TNFR. This was demonstrated in NIH 3T3 cells transfected with the human p55TNFR, where cytotoxicity is mediated exclusively by the transfected receptor. Although the p55ATNFR had virtually identical affinities for TNF and LT alpha, as defined by Scatchard analysis, it nevertheless discriminated between binding of each cytokine and showed a 200-fold enhanced cytotoxicity mediated by TNF.

3T3 Cells↗
PubMed1995

Atypical skeletal tuberculosis.

Tuberculosis remains a major cause of skeletal infection in many parts of the world. With the advent of acquired immune deficiency syndrome (AIDS) and mass emigration from underdeveloped to industrialized nations this past decade, a new patient population is being encountered in which extrapulmonary tuberculosis is not uncommon and atypical presentations may confuse the diagnosis. Our recent experience with an unusual presentation has prompted this report.

Adult↗
PubMed1995

Cephalad sacral resection with a combined extended ilioinguinal and posterior approach.

A combined anterior and posterior approach was used for the resection of a large tumor (a chordoma, a giant-cell tumor, an osteosarcoma, or a chondrosarcoma) of the cephalad part of the sacrum in twelve patients. The anterior aspect of the sacrum was exposed through an extended ilioinguinal approach, and the posterior aspect, through a midline approach. This widely extensile procedure permitted simultaneous visualization of the anterior, posterior, and circumferential aspects of the sacrum at the time of the osteotomy and facilitated the resection of these difficult lesions. At the time of follow-up (average duration for the eleven surviving patients, thirty-seven months; median, thirty months; range, twenty to sixty-nine months), ten patients were able to walk independently (four with the use of a cane) and one was confined to a wheelchair. One patient had died immediately postoperatively. The results of the present study indicate that a combined extended ilioinguinal and posterior approach can be used effectively for the wide resection of a tumor arising in the cephalad part of the sacrum.

Adult↗
PubMed1994

God's fools.

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Biological Evolution↗
PubMed1994

Helicobacter pullorum sp. nov.-genotype and phenotype of a new species isolated from poultry and from human patients with gastroenteritis.

Campylobacter-like organisms were isolated from the liver, duodenum and caecum of broiler and layer chickens, and from humans with gastroenteritis. They formed a unique DNA homology group and a polyphasic taxonomic analysis was made of 16 strains. Analysis of the nucleotide sequence of the 16S rRNA gene from seven of the strains identified them as belonging to a single species, within the genus Helicobacter. This conclusion was supported by the studies of relative DNA homology and of total protein electrophoretic patterns. The new species could be biochemically differentiated from other helicobacters and its ultrastructure in the electron microscope was typical of the genus except that the flagellum was not sheathed. We propose the name Helicobacter pullorum sp. nov. for this group. Like H. fennelliae or H. cinaedi it represents another non-gastric urease-negative Helicobacter species colonizing the lower bowel. Its isolation from the livers of chickens with vibrionic hepatitis is significant. We describe a species-specific PCR assay for H. pullorum sp. nov. which will facilitate its identification and further studies of its epidemiology.

Animals↗
PubMed1994

Nazi doctors.

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Anthropology, Cultural↗