Search PubMed⌕ Search

Biomedical subjects

S Anderson

Publications and source records attributed to S Anderson.

At least 631 records · Page 35Linked to original sources
PubMedDate not supplied

The role of stressors and psychosocial variables in the stress process: a study of chronic caregiver stress.

OBJECTIVE: An investigation was conducted 1) to examine the relative importance of stressor types (ie, daily hassles, caregiving-specific stressors, and life events) on the stress response, 2) to assess the stability of relationships between psychosocial variables and stress over a 6-month period, and 3) to explore how the nature and magnitude of the contributions made by stressors and psychosocial factors to the stress process varied according to the qualitative characteristics of the stress response (ie, anxiety, depression, and stress). METHODS: Fifty spousal caregivers of patients with dementia were recruited and asked to participate in a detailed psychosocial evaluation at 3-month intervals; the evaluation involved measurement of stressor frequency, psychosocial variables, and indices of the stress response (ie, anxiety, depression, and stress). RESULTS: The data revealed that the effects of stressors and psychosocial factors on the stress response were considerable (accounting for 49-63% of the variance in stress response measures). Furthermore, there was some evidence of stability in the effects of the stressor and mediator variables on the stress response. Specifically, the contributions of life events and caregiver difficulties were largely consistent at both 3 and 6 months, and the psychosocial factor of "reactive coping and self-appraisal" influenced all three stress response indices at both 3 and 6 months. CONCLUSIONS: There is some evidence of stability in the effects of stressors and psychosocial variables on the stress process over a 6-month period. However, it would also seem that the nature of the stress process differs according to the qualitative characteristics of the stress response.

Adaptation, Psychological↗
PubMedDate not supplied

Topotecan and liposomal doxorubicin in recurrent ovarian cancer: is sequence important?

A variety of agents have emerged to treat patients with recurrent epithelial ovarian cancer (EOC). Most patients receive both topotecan (T) and liposomal doxorubicin (D); however, there are no data regarding the benefit of a sequence-D followed by T (DT) or T followed by D (TD). We identified 89 consecutive patients with recurrent EOC, who received both D and T from January 1994 to January 2004 at Memorial Hospital. We compared the duration of treatment, toxicity, and overall survival (OS) for patients who received either DT or TD. Sixty-four patients received DT, and 25 patients received TD. The groups were balanced regarding age, stage, surgical debulking, platinum sensitivity, prior therapy, and intervening drugs between D and T. Median numbers of cycles on DT and TD were seven and six, respectively (P= 0.61); there was no difference in duration based on platinum sensitivity. Removal from therapy for toxicity was similar, DT (22%) and TD (36%) (P= 0.18). Finally, there was no difference in median OS based on sequence, DT (18.28 months) and TD (17.75 months) (P= NS). Platinum sensitivity did not affect median OS based on sequence. Based on duration, toxicity, and OS there is no advantage of one sequence of D and T when treating patients with recurrent EOC.

Adenocarcinoma↗
PubMedDate not supplied

Ras modulates commitment and maturation of 10T1/2 fibroblasts to adipocytes.

The positive association of the ras oncogene with human cancer and the recognition that malignancy may, in part, represent the imbalance between cell proliferation and differentiation have generated intense interest in the potential role of ras in cell differentiation. We investigated this possibility utilizing as a model system the differentiation of the mesenchymal cell line C3H 10T1/2 (10T1/2) to adipocytes, and a series of transfectants of 10T1/2 cells in which the level of the ras gene product (p21ras; Ras) can be effectively up- or down-modulated. In agreement with previous reports, we found that 10T1/2 cultures, propagated in the resting state for several weeks, spontaneously convert to fat cells at a very low frequency. Downmodulation of endogenous p21ras levels, as a consequence of expression of antisense ras, markedly increased the rapidity and frequency of adipose conversion (6- to 10-fold), which was equivalent in magnitude to that effected by the potent differentiating agent 5-azacytidine. Conversely, overexpression of ras completely inhibited cell differentiation. In addition, adipocytes derived from antisense-ras expressing lines were characterized by a decrease in hormone responsiveness, as well as an apparent deficiency in attaining the terminally differentiated state. These findings suggest that Ras may be a negative regulator of the decision-making step of fibroblast differentiation to adipocytes. In addition, Ras may play an essential positive role in the transduction of hormonal signals necessary for full adipocyte maturation during later progression along the differentiation pathway.

Adipose Tissue↗
PubMedDate not supplied

Ambulatory ventricular arrhythmias in patients with heart failure do not specifically predict an increased risk of sudden death. PROMISE (Prospective Randomized Milrinone Survival Evaluation) Investigators.

BACKGROUND: Ventricular arrhythmias are a frequent finding in congestive heart failure (CHF) patients and a cause of concern for physicians caring for them. Previous studies have reached conflicting conclusions regarding the importance of ventricular arrhythmias as predictors of sudden death in patients with CHF. This study examined the independent predictive value of ventricular arrhythmias for sudden death and all-cause mortality in PROMISE (Prospective Randomized Milrinone Survival Evaluation). METHODS AND RESULTS: Ventricular arrhythmias were analyzed and quantified by use of prespecified criteria on baseline ambulatory ECGs from 1080 patients with New York Heart Association (NYHA) class III/IV symptoms and a left ventricular ejection fraction </=35% enrolled in PROMISE. The relationship of ventricular arrhythmias and other clinical parameters to overall mortality and sudden death classified by an independent, blinded mortality committee was determined. There were 290 deaths, of which 139 were classified as sudden. Of the several measures of ventricular ectopy that were univariate predictors, the frequency of nonsustained ventricular tachycardia (NSVT) was the most powerful predictor and remained a significant independent predictor when included with other clinical variables in multivariate models of both sudden death mortality and non-sudden death mortality. However, multiple logistic analysis with models including the clinical variables with and without the NSVT variable demonstrated that the frequency of NSVT did not add significant information beyond the clinical variables. CONCLUSIONS: This study demonstrates that ventricular arrhythmias do not specifically predict sudden death in patients with moderate-to-severe heart failure. Thus, the finding of asymptomatic NSVT on ambulatory ECG does not identify specific candidates for antiarrhythmic or device therapy.

Arrhythmias, Cardiac↗
PubMedDate not supplied

Influence of antihypertensive therapy on development and progression of diabetic glomerulopathy.

Capillary hypertension is suggested to be the underlying cause of microvascular disease affecting the kidney, the retina, and other organs and tissues in diabetic patients and animals. Hyperglycemia causes an expansion of extracellular volume, which induces a vasodilatory response. Hemodynamic adaptation to vasodilation leads to an increase in intracapillary hydraulic pressure, which subsequently causes vascular damage. In experimental animals, restoration of capillary pressure to normal levels by ingestion of a low-protein diet or administration of an angiotensin I-converting enzyme inhibitor has been shown to prevent microvascular damage in the kidney, and dietary protein restriction limits injury in the retina as well. Atrial natriuretic peptide, which is secreted by atrial myocytes in response to volume expansion, may be involved in mediation of the hemodynamic adaptation (vasodilatory response) that results in diabetic microvascular disease.

Animals↗
PubMedDate not supplied

Hyperthermia treatment planning and temperature distribution reconstruction: a case study.

While a great deal of effort has been applied toward solving the technical problems associated with modelling clinical hyperthermia treatments, much of that effort has focused on only estimating the power deposition. Little effort has been applied toward using the modelled power depositions (either electromagnetic (EM) or ultrasonic) as inputs to estimate the hyperthermia induced three-dimensional temperature distributions. This paper presents a case report of a patient treated with hyperthermia at the Duke University Medical Center where numerical modelling of the EM power deposition was used to prospectively plan the treatment. Additionally, the modelled power was used as input to retrospectively reconstruct the transient three-dimensional temperature distribution. The modelled power deposition indicated the existence of an undesirable region of high power in the normal tissue. Based upon this result, amplitudes and phases for driving the hyperthermia applicator were determined that eliminated the region of high power and subsequent measurements confirmed this. The steady-state and transient three-dimensional temperature distributions were reconstructed for four out of the seven treatments. The reconstructed steady-state temperatures agreed with the measured temperatures; root-mean-square error ranged from 0.45 to 1.21 degrees C. The transient three-dimensional tumour temperature was estimated assuming that the perfusion was constant throughout the treatment. Using the computed three-dimensional transient temperature distribution, the hyperthermia thermal dose was computed. The equivalent minutes at 43 degrees C achieved by 50% (T50Eq43) of the tumour volume was computed from the measured data and the three-dimensional reconstructed distribution yielding T50Eq43 = 40.6 and 19.8 min respectively.

Arm↗
PubMedDate not supplied

Peripheral blood progenitor cell cycle kinetics following priming with pIXY321 in patients treated with the "ICE" regimen.

PURPOSE: Treatment with hematopoietic growth factors increases the percentage of hematopoietic progenitor cells in cell cycle. Following withdrawal of certain growth factors, preclinical data suggest that there is a transient fall in the percentage of progenitor cells in cycle below the baseline, thus providing a window to administer chemotherapy with reduced risk of myelotoxicity. PATIENTS AND METHODS: Patients with histologically confirmed, previously untreated neoplasia, were treated with pIXY321 by subcutaneous injection at a dose of 375 microg/m2 twice daily (total dose 750 microg/m2/day) for seven days (days -8 to -2), followed by a two-day rest (days -1 to 0). Patients received ICE (ifosfamide, carboplatin and etoposide) on days 1 to 3. On day 4, pIXY321 was resumed until hematologic recovery. Peripheral blood was collected on days -8, -2, -1, 1, and cell cycle distribution was determined using flow cytometry. RESULTS: Twenty patients were treated in this study and received a total of 54 cycles. Partial responses were observed in three of 13 patients with non-small cell lung cancer (23 percent) and two of five patients with small cell lung cancer (40 percent). Six of 15 patients had an increased number of cells in S+G2/M on day 1 of ICE following seven days of pIXY321 and two days off (days -1 to 0). The average increase was 63 percent (range 6-253). Seven patients had a decreased number of cells in S+G2/M. The average decrease was 55 percent (range 6.3-78). There were no significant differences among the fifteen patients with regards to the observed toxicity of the chemotherapy. DISCUSSION: pIXY321 in this schedule did not consistently decrease the percentage of cycling progenitor cells in the peripheral blood. Future studies should define whether other growth factors and/or schedules can synchronize progenitor cell cycling and protect the marrow compartment from cycle specific chemotherapy.

Adult↗
PubMedDate not supplied

The hospitalist.

Efforts to improve the efficiency and quality of hospital inpatient care have led to the movement to replace the primary care physician with the hospitalist as the inpatient physician of record. A hospitalist serves as the physician of record after accepting referrals of hospitalized patients from primary care physicians. The hospitalist then keeps the primary care physician informed of major healthcare decisions during the patient's entire hospital stay. One of the forces promoting the hospitalist movement is the assumption that inpatient care provided by a small number of physicians is less costly, of higher quality, and less variable than the care provided by primary care physicians who see patients only briefly once a day. Hospitalists are accessible throughout their shifts and can better respond to changing patient needs. With this model of care, hospitalists have taken a more proactive role in redesigning support-care systems based on the needs of the patient. Many perform quality improvement and utilization review, and engage in the development of clinical practice guidelines. Concern over the hospitalist model has focused on the break in continuity of care. Patients and their families may feel that they are losing a physician whom they know and for whom they have some level of comfort and confidence. As the hospitalist movement picks up momentum, so too does its expectation to improve and provide for quality end of life care.

Case Management↗
PubMedDate not supplied

Breast tumor recurrence following lumpectomy with and without breast irradiation: an overview of recent NSABP findings.

The latest findings from the NSABP B-06 trial on ipsilateral breast tumor recurrence (IBTR) continue to demonstrate that through 9 years of follow-up more patients treated with radiation remained IBTR free as compared to those receiving no radiation (P less than 0.001), regardless of age, nodal status, or tumor size. There is no significant difference in distant disease-free survival (DDFS) or survival between the two lumpectomy groups despite the highly significant difference in their probability of remaining IBTR free. A recent analysis shows that when a patient is diagnosed with an IBTR, the risk of distant metastatic disease increases, indicating that an IBTR is a marker for, not a cause of, distant metastatic disease. An IBTR indicates a greater risk for distant disease when the primary tumor was removed. Mastectomy or breast irradiation following lumpectomy eliminates or reduces the opportunity for identifying a marker of risk for distant disease, thus emphasizing the importance of an IBTR beyond the need for its removal. Since an IBTR is associated with a relative risk of 3.41 for the development of distant metastatic disease, systemic therapy subsequent to an IBTR should be considered. Evidence presented from recent NSABP studies indicates the value of systemic therapy for lowering the incidence of IBTR following lumpectomy and breast irradiation.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Ipsilateral breast tumor recurrence and survival following lumpectomy and irradiation: pathological findings from NSABP protocol B-06.

Ipsilateral breast tumor recurrence (IBTR) occurred in 42 of 488 (9%) pathologically evaluable patients enrolled in NSABP protocol B-06 with a mean potential follow-up of 103 months (range 68-161 months) following treatment for Stage I and II invasive breast cancer by lumpectomy and local breast irradiation (LXRT). IBTR were observed at or close to the same quadrant as the index cancers and their histologic types and nuclear grades were similar if not identical in 95 and 93%, respectively. This information confirms our earlier findings which indicated that multicentricity is of little or no clinical significance in the treatment of breast cancer by LXRT; breast cancers rarely if ever change their biologic potential once clinically detected; and lastly, most if not all IBTR represent residual cancer. Cox regression analyses revealed only a patient age less than 35 years to be significantly related to IBTR. No relationship between IBTR and so-called extensive intraductal component (EIC) or 31 other pathologic features of the index cancers was found. Overall survival was significantly related to nodal status (P = 0.01), nuclear grade (P = less than 0.001) histologic tumor type (P = 0.01) and IBTR (P = less than 0.001). This latter was considered as an indicator rather than instigator of distant disease and reduced survival since the latter is no different in patients treated by LXRT, lumpectomy alone after which IBTR is much more frequent, or mastectomy, which precludes its expression. We conclude that there are as yet no viable markers which would contraindicate treating patients with breast cancer by LXRT.

Adult↗
PubMedDate not supplied

Shifts in medical student beliefs about AIDS after a comprehensive training experience.

We evaluated the beliefs of second-year medical students regarding critical issues in the AIDS epidemic before and after an intensive two-day training symposium. Paired responses, collected for three consecutive years, were available for 187 students. Our results indicate that, although the students generally held progressive beliefs on prevention and public policy prior to training, a significant minority held views that differ from expert opinion. After the training experience, we observed substantial shifts of opinion on several issues. For example, among those who initially believed that physicians should record results of HIV testing in patient charts without patient permission, 45% shifted to disagreement. On mandatory premarital testing, 43% of those initially supporting it shifted to disagreement. On some issues, such as contact tracing, where expert opinion is less clear, student opinion moved very little overall. Over the three-year period, we found evidence of a trend towards less concern over HIV transmission to men from causal sex with infected female partners and a trend towards acceptance of glove-wearing when handling all blood specimens. In conclusion, we demonstrate that the beliefs of medical students concerning difficult issues posed by the AIDS epidemic can be changed substantially in the short-term by a specially designed intensive educational program. Reinforcement and persistence of these changes should now be a concern for medical educators.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Inspiring nursing students to mobilize communities in Nepal.

In 1987 nurse educators in Nepal implemented a revised certificate nursing curriculum oriented toward primary health care (PHC) and a bachelor of community health nursing (CHN) curriculum with emphasis on leadership in PHC. As both curricula included practical experience for nursing students in the community, the teachers had to strategize how to maximize both the students' learning and their contribution to community health. Below, how the educators encouraged reluctant students to not only participate in PHC activities but also change their negative attitudes about working in remote areas of Nepal.

Community Health Nursing↗
PubMedDate not supplied

Experimental development of a fixed volume, gravity draining, prosthetic urinary bladder.

A fixed volume, semi-rigid, gravity draining prosthetic urinary bladder has been developed in experimental animals. The conceptual model demands: 1) an encrustation resistant lumenal surface; 2) successful urothelial-prosthesis and bowel-prosthesis anastomoses; 3) a transcutaneous abdominal wall prosthesis that bonds with skin, muscle, bladder, and peritoneum which resists external and intraluminal bacterial challenge; and 4) an air permeable, fluid impermeable filter which allows passive filling and gravity evacuation of urine. The principles involved have been successfully tested in rodents, rabbits, swine, and dogs. To date two total alloplastic prosthetic bladders fabricated from Biolor II and Proplast have been inserted in mini-swine for 4 weeks.

Animals↗