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Biomedical subjects

F Baker

Publications and source records attributed to F Baker.

At least 19 recordsLinked to original sources
PubMed1995

Peritonitis rate: traditional versus low calcium dialysate.

The results of nonrandomized retrospective studies have suggested that low calcium dialysate (LCD; ionized calcium concentration 1.25 mmol/L) is associated with a higher peritonitis rate than traditional dialysate (TD; ionized calcium concentration 1.75 mmol/L). For this reason, 86 consecutive new continuous ambulatory peritoneal dialysis patients were randomized, in a single-blind fashion, to TD or LCD for 1 year. The results were analyzed on an intention-to-treat basis, no matter what fluid or what modality of treatment was being used at the end of the year. The two groups were well matched at baseline. At 1 year, 28 of 43 TD patients were still on continuous ambulatory peritoneal dialysis (one had a catheter changed due to peritonitis), four had a working transplant, one had recovered renal function, nine had died, and one had been transferred to hemodialysis because of peritonitis. Twenty-seven of 43 LCD patients were on continuous ambulatory peritoneal dialysis (one catheter change), nine had a working transplant, six had died, and one was on hemodialysis. There were 17 proven (33 possible) peritonitis episodes in 417 patient-months in the TD group. In the LCD group, there were 17 (35 possible) episodes in 432 patient-months. The proven peritonitis rate was 0.49 episodes/patient/yr in the TD group versus 0.48 episodes/patient/yr in the LCD group (P = NS). In conclusion, there is no controlled evidence that LCD is associated with a higher incidence of peritonitis than TD.

Calcium↗
PubMed1994

In vitro parameters and treatment outcome in head and neck cancers treated with surgery and/or radiation: cell characterization and correlations with local control and overall survival.

PURPOSE: To determine whether in vivo parameters (surviving fraction at 2 Gy, alpha values, and calculated cell growth fraction) were predictive of the treatment outcome. METHODS AND MATERIALS: Biopsies were obtained from patients with a head and neck tumor. In vitro parameters were determined using the CAM plate assay. Cell characterization by cytogenetic analysis was performed on 19 different cell cultures. In 25 additional cell cultures, cell clonogenicity was tested using the Courtenay Mills assay. RESULTS: Biopsies were obtained from 156 patients with a head and neck tumor and the oropharynx was the predominant primary site. In vitro parameters were obtained in 113 cases (72%) (SF2 in 93 cases and calculated cell growth fraction in 103 cases). Cell characterization showed that cells in CAM plates were diploid with no clonal chromosome abnormalities and gave colonies in soft agar with a mean cloning efficiency of 1.610(-3). Only patients treated with surgery and/or radiation (76), were considered eligible for in vitro parameters and treatment outcome correlation studies. The mean follow-up is over 2 years (range 9-47 months). The local control rate was significantly higher (p = 0.04) for patients with alpha values above the cut-off point of 0.07 Gy-1 (69% vs. 38% at 2 years). The local control rate was also significantly higher (p = 0.04) for patients with calculated cell growth fraction values about the cut-off point of 0.06% (70% vs. 48% at 2 years). Moreover for these latter patients the overall survival rate was also significantly higher (p = 0.004) (54% vs. 26% at 2 years). It is worth noting that alpha and calculated cell growth fraction values below the cut-off points identified a small group of patients (about 20%) who were at a significantly high risk of local failure. From a pragmatic point of view, as only radiosensitivity or calculated cell growth fraction values could be obtained in a certain number of experiments due to technical reasons, the treatment outcome of patients who had either alpha and/or calculated cell growth fraction values below the cut-off levels (about 30% of all patients) was analyzed. This group of patients fared significantly worse (p = 0.02) in terms of local control (50% vs. 68% at 2 years) and (p = 0.04) overall survival (36% vs. 50% at 2 years). CONCLUSION: These results suggest that in vitro parameters using the CAM plate assay, might be useful in predicting the treatment outcome of patients with a head and neck tumor treated with surgery and postoperative radiation, or radiation alone. However, they must be considered as preliminary because the cut offs used in the study were chosen for exploratory purposes. Only a multivariate analysis including all clinical and biologic factors will allow us to draw any firm conclusions.

Carcinoma, Squamous Cell↗
PubMed1994

Psychosocial sequelae of bone marrow transplantation.

Bone marrow transplantation is a particularly arduous treatment and a source of considerable stress for patients and their families. Psychological sequelae include psychological distress, concern about loss of control, physical complications, sexual dysfunction, difficulties in social relationships, occupational disability, and financial consequences. Patient education that can help BMT recipients and their families know what to expect at the different stages of treatment may help alleviate anxiety and fear of the unknown. Communication should be individualized according to the needs of the particular patient and family. The patient's ability to use information should be considered in deciding what to convey to him or her. To be most effective, patient education should take place throughout the BMT process and should be multidisciplinary.

Anxiety↗
PubMed1992

Social support and quality of life of community support clients.

Two aspects of social support, availability and adequacy, were assessed for 729 severely mentally ill adults enrolled in seven state-supported Community Support Services (CSS) programs as part of repeated questionnaire surveys nine months apart. Perceived quality of life interviews with the clients were also conducted at both times. These interviews included the Bradburn Positive and Negative Affect Scales and the Satisfaction with Life Domains Scale (SLDS). Availability of social support was significantly correlated with positive affect over time, but not with negative affect at either point. Inadequacy of social support was significantly related to negative affect at both assessments. Both availability and adequacy of social support were significantly related to the SLDS at each time. Change in satisfaction with life domains was found to be related to both availability and, to a lesser degree, with adequacy of social support.

Adolescent↗
PubMed1992

The unstable Hb Hammersmith or alpha 2 beta 2(42)(CD1)Phe----Ser observed in an Indian child; identification by HPLC and by sequence analysis of amplified DNA.

We have identified the unstable hemoglobin variant present in a Chipewayan Indian patient with severe hemolytic anemia as Hb Hammersmith or alpha 2 beta 2(42)(CD1)Phe----Ser. Her parents were normal. Identification was greatly facilitated by the use of reversed phase high performance liquid chromatography for the isolation of the beta X chain and its tryptic fragments, and of sequence analysis of amplified DNA which readily identified a TTT(Phe)----TCT(Ser) mutation at codon 42.

Base Sequence↗
PubMed1992

Sexual satisfaction in survivors of bone marrow transplantation.

Of 157 (80%) adult survivors of bone marrow transplantation, 126 responded to a mailed survey 6-149 months after transplant concerning their ability to attain sexual satisfaction. Sixty-five percent of the subjects indicated some degree of sexual satisfaction (with 29% indicating a high degree of satisfaction). Thirteen percent were neutral and 22% were dissatisfied. Gonadal physiological disturbances were present in most subjects as a result of intensive treatments. Fifty-seven percent of women were receiving estrogen replacement, and only 40% had regular menses. Twenty-four percent of men had difficulty with erections and 13% had ejaculatory dysfunction. For men, difficulties with erection (r = 0.54, p less than 0.001) or ejaculation (r = 0.52, p less than 0.001) were associated with inability to attain sexual satisfaction. For women, loss of menses (r = 0.34, p = 0.008) was associated with inability to attain sexual satisfaction. Although few women had abnormally low serum estradiol (even with hormonal supplementation), and none of the 43 men tested had abnormally low serum testosterone, sexual satisfaction correlated with serum levels of estrogen in women (r = 0.42, p = 0.04) and serum testosterone in men (r = 0.28, p = 0.04). Forty-two subjects rated their level of sexual satisfaction before and after transplant. Post-transplant satisfaction was not associated with pretransplant satisfaction (r = 0.07, p = 0.67).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Health, functional status, and employment of adult survivors of bone marrow transplantation.

OBJECTIVE: To determine the health, functional ability, and employment status of adults who survive bone marrow transplantation. DESIGN: Inception cohort study. SETTING: Patients who received transplants at a single referral-based center. PATIENTS: Adults of 18 years of age or older who had received bone marrow transplants at least 6 months previously and who were not in a life-threatening relapse were surveyed a mean of 47 months after transplant (median, 37 months; range, 6 to 149 months). Of 171 eligible patients, 157 were contacted and 135 (86%) responded. MEASUREMENTS AND MAIN RESULTS: Patients completed a mailed survey. Medical records were also reviewed. Most patients (93%) reported they could do normal activities with minor or no physical problems (Karnofsky scores, greater than or equal to 80%). Global health was described as good to excellent by 67% of subjects. Most perceived social activities (80%) or physical functional abilities (67%) to be unimpaired or only slightly affected. Moderate or severe pain was uncommon (13%). Sixty-five percent had returned to full- or part-time employment, and one third of those who were not employed were attending school. Job discrimination and problems in obtaining insurance were reported by 23% and 39%, respectively. Among those who had been employed before illness, loss of employment was associated with lower social functioning, chronic graft-versus-host disease, greater job discrimination, and female gender using multivariate logistic regression. CONCLUSIONS: Most subjects surviving bone marrow transplant reported good to excellent health and functional ability. Three fourths were employed or enrolled in school. These outcomes are comparable to outcomes in survivors of cancer who received less intensive treatments.

Activities of Daily Living↗
PubMed1991

The density of clonogenic cells in human solid tumors.

Considering that tumors are maintained by clonogenic cells, and that the primary target in the therapy of cancer is the clonogenic cell, the density of clonogens in a tumor could become an important parameter in quantitating the response to therapy. Indirect methods for determining the density of clonogenic cells in human tumors based on the response of tumors to radiation suggest there are circa 1 X 10(5) clonogens per gram with a large range. Direct methods, based on the measurement of cloning efficiency of enzymatically disaggregated biopsies of human tumors in soft agar, suggest a clonogen density of approximately 1,500 clonogens per gram. As this value is inconsistent with the prior data, we chose to determine the density of clonogenic cells in human tumors by assaying the enzyme digest of biopsies of human tumors for clonogenic cells using an enriched monolayer clonogenic assay. We determined the average clonogen density to be 1.12 x 10(5) clonogens per gram with a large range. The agreement with the indirect method suggests that the enriched monolayer clonogenic assay supports the proliferation of the cell population responsible for maintaining the tumor.

Cells, Cultured↗
PubMed1991

A behavior setting assessment for community programs and residences.

Using the concept of person-environment fit to determine the effectiveness of residential and program placements for chronic psychiatric clients requires systematic and concrete information about these community environments in addition to information about the clients themselves. The conceptual and empirical development of the Behavior Setting Assessment (BSA), a measure based on Barker's behavior setting theory, is described. Use of the BSA with 28 residences (117 settings) and 11 programs (176 settings) from two community support systems demonstrated that all 293 settings assessed could be described and analyzed in terms of differences in their demands for self-care skills, food preparation and consumption, verbal/cognitive responses, and solitary or group activities. The BSA is an efficient measure for obtaining specific, concrete information about the behavioral demands of important community environments.

Activities of Daily Living↗
PubMed1991

Role retention and quality of life of bone marrow transplant survivors.

Bone marrow transplantation (BMT) offers the potential for survival of 50% or more for selected patients with malignant disease not controlled by other means. However, BMT introduces risks for psychological, social, and physical impairment and the potential for significant loss in one's ability to retain important role relationships. While there has been a sharp increase in the performance of BMTs in the past decade, there has been little research on its effects on long-term survivors. This paper presents the results of a follow-up survey of 135 survivors of BMT at the Johns Hopkins Oncology center. The ability of the survivors to maintain valued social roles is examined as this affects perceived quality of life. The main hypothesis of the paper, that role retention is significantly related to higher quality of life, is supported by significant correlations of role retention with quality of life as measured by the Satisfaction with Life Domains Scale, current and future life satisfaction on Cantril Self-Anchoring Ladders, and by the Bradburn Positive Affect Scale. While the Bradburn Negative Affect Scale was not significantly related to role retention, total negative mood as measured by the Profile of Mood States was inversely related to role retention at a statistically significant level.

Adaptation, Psychological↗
PubMed1991

Influence of nifedipine on cyclosporin A nephrotoxicity after unilateral nephrectomy in the spontaneously hypertensive rat.

1. Nifedipine ameliorates cyclosporin A-induced renal impairment in surgically intact (two-kidney) rats. This study investigates the effect of nifedipine on cyclosporin A nephrotoxicity in spontaneously hypertensive rats after either uninephrectomy or uninephrectomy with contralateral renal denervation. 2. Fourteen days after uninephrectomy pair-fed rats were injected for 14 days with cyclosporin A (25 mg/kg body weight) via the subcutaneous route and with nifedipine (0.1 mg/kg body weight) via the intraperitoneal route. Renal and systemic haemodynamics were measured in conscious unrestrained rats. 3. Whole-blood levels of cyclosporin A did not differ between groups (overall 352 +/- 22 ng/ml, means +/- SEM). After uninephrectomy, cyclosporin A decreased the glomerular filtration rate (olive oil versus cyclosporin A: 0.96 +/- 0.04 versus 0.70 +/- 0.06 ml min-1 100 g body weight, P less than 0.02) and effective renal plasma flow (1.94 +/- 0.10 versus 1.38 +/- 0.13, P less than 0.01), and increased renal vascular resistance [(20.2 +/- 1.8) x 10(4) versus (31.6 +/- 3.3) x 10(4) kPa l-1 s [(20.2 +/- 1.8) x 10(3) versus (31.6 +/- 3.3) x 10(3) dyn s cm-5], P less than 0.02] and mean arterial pressure (146.7 +/- 6.7 versus 167.3 +/- 2.9 mmHg, P less than 0.05). Neither renal denervation nor nifedipine prevented the reduction in glomerular filtration rate or effective renal plasma flow induced by cyclosporin A. 4. This study infers that the sympathetic nervous system does not play an active role in cyclosporin A nephrotoxicity and demonstrates that the concomitant administration of nifedipine to rats with reduced renal mass does not ameliorate cyclosporin A-induced renal impairment.

Animals↗
PubMed1991

Localization of recurrent medullary thyroid carcinoma with technetium-99m-methoxyisobutylnitrile scintigraphy: a case report.

This case report demonstrates the successful localization of metastatic medullary thyroid carcinoma with 99mTc-labeled methoxyisobutylnitrile (MIBI). Disease recurrence was initially localized using 201Tl and by immunoscintigraphy with 111In-labeled anti-carcinoembryonic antigen (anti-CEA) antibody fragments. Scintigraphy with 99mTc-MIBI yielded higher target-to-background ratios than 201Tl or 111In-anti-CEA. Technetium-99m-MIBI may be a useful agent in the localization of recurrent medullary thyroid carcinoma.

Carcinoma↗
PubMed1990

Housing environments and community adjustment of severely mentally ill persons.

This study examined relationships between the quality and appropriateness of housing environments and community adjustment of 729 deinstitutionalized severely mentally ill clients in a state-wide community support service program. Environmental measures included ratings of the physical condition of the client's residence, its adequacy for six key life activities, and the overall appropriateness of the residential setting for the client. Community adjustment measures included global level of functioning, degree of maladaptive behavior and client's perceived quality of life. Evidence is presented that quality and appropriateness of housing environments significantly affect aspects of client's community adjustment outcomes over a nine-month period.

Adult↗
PubMed1990

Effect of nifedipine on renal haemodynamics in an animal model of cyclosporin A nephrotoxicity.

1. This study investigates the effect of nifedipine on cyclosporin A nephrotoxicity in the spontaneously hypertensive rat. 2. Cyclosporin A, administered daily by subcutaneous injection at 25 mg/kg body weight for 14 days, induced a significant reduction in glomerular filtration rate (35.3%) and effective renal plasma flow (45.0%), and an increase in renal vascular resistance (219%). Using this regimen, tubular, glomerular or vascular morphological damage was not evident on light microscopy. 3. The administration of nifedipine simultaneously with cyclosporin A from day 1 prevented the characteristic decline in renal function and increase in renal vascular resistance. However, the administration of nifedipine to spontaneously hypertensive rats previously exposed to cyclosporin A for 7 days failed to improve renal haemodynamics. 4. This study suggests that the beneficial effect conferred by nifedipine on cyclosporin A nephrotoxicity is present only when treatment is initiated simultaneously with cyclosporin A.

Animals↗
PubMed1990

Risk communication about environmental hazards.

The development of the new field of risk communication of environmental hazards is briefly described and the term "risk communication" is defined. This is followed by a description of the eight basic steps in risk communication about environmental hazards including: 1) assessing the risk; 2) setting goals; 3) assessing the target audiences; 4) assessing the socio-cultural context; 5) choosing the approach; 6) constructing the communications; 7) implementing the risk program; and 8) evaluating the effects. In describing each step, relevant literature concerning risk communication is reviewed.

Communication↗
PubMed1989

2,3-Dihydro-5-benzofuranols as antioxidant-based inhibitors of leukotriene biosynthesis.

The enzymes that catalyze the oxidative metabolism of arachidonic acid have provided fertile ground for the development of useful therapeutic agents for nearly a quarter century. Inhibitors of the enzyme cyclooxygenase prevent the formation of the prostaglandins and thromboxanes and are clinically useful antiinflammatories and peripheral analgesics. More recently it has been discovered that the enzyme 5-lipoxygenase is the first step in the formation of a series of biologically important metabolites of arachidonic acid, the leukotrienes. Evidence suggests that an inhibitor of 5-lipoxygenase may be a useful therapeutic agent in the treatment of asthma, immediate hypersensitivity, and inflammation. Various antioxidants have been examined as inhibitors of 5-lipoxygenase in vitro. We were intrigued by recent reports that the 2,3-dihydro-5-benzofuranol ring system maximizes the stereoelectronic effects necessary for efficient hydrogen atom abstraction by peroxyl radicals. In this study we describe the synthesis of over 50 new 2,3-dihydro-5-benzofuranols and their biological evaluation as inhibitors of leukotriene biosynthesis in isolated human polymorphonuclear leukocytes. We show that the 2,3-dihydro-5-benzofuranol ring system, although not a potent inhibitor of leukotriene biosynthesis in itself, can provide a useful template for the design of antioxidant-based inhibitors of leukotriene biosynthesis. Furthermore, within a structural class the potency of a given analogue can be predicted on the basis of its overall calculated lipophilicity (log P). The data are interpreted in terms of a model in which the observed inhibition by this class of inhibitors is dependent on the intrinsic ability of the antioxidant to reduce the enzyme and on the fraction of the inhibitor that is partitioned into the membrane.

Antioxidants↗