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Biomedical subjects

L Rice

Publications and source records attributed to L Rice.

At least 19 recordsLinked to original sources
PubMed1999

Neocytolysis contributes to the anemia of renal disease.

Neocytolysis is a recently described physiological process affecting the selective hemolysis of young red blood cells in circumstances of plethora. Erythropoietin (EPO) depression appears to initiate the process, providing the rationale to investigate its contributions to the anemia of renal disease. When EPO therapy was withheld, four of five stable hemodialysis patients showed chromium 51 (51Cr)-red cell survival patterns indicative of neocytolysis; red cell survival was short in the first 9 days, then normalized. Two of these four patients received oral 13C-glycine and 15N-glycine, and there was a suggestion of pathological isotope enrichment of stool porphyrins when EPO therapy was held, again supporting selective hemolysis of newly released red cells that take up the isotope (one patient had chronic hemolysis indicated by isotope studies of blood and stool). Thus, neocytolysis can contribute to the anemia of renal disease and explain some unresolved issues about such anemia. One implication is the prediction that intravenous bolus EPO therapy is metabolically and economically inefficient compared with lower doses administered more frequently subcutaneously.

Adult↗
PubMed1999

Use of real time pulsed field gel electrophoresis to guide interventions during a nursery outbreak of Serratia marcescens infection.

BACKGROUND: Pulsed field gel electrophoresis (PFGE) is a commercially available technique that can establish clonal relationships among many common hospital-derived organisms with a high degree of accuracy and can yield results in a sufficiently short time to guide interventions during an outbreak investigation. METHODS: The CHEF Genomic Bacterial DNA Plug Kit (Bio-Rad) was applied to an unfolding nursery outbreak of Serratia marcescens infections according to the manufacturer's guidelines. Bacterial genomic DNA was digested with XbaI or SpeI and separated on 1% agarose gels, and the isolates were grouped by restriction endonuclease patterns according to established standards. RESULTS: S. marcescens was isolated from nine patients in an intensive care nursery during an 8-week period. Initial PFGE analysis performed after identification of the first eight patients, when closure of the nursery was imminent, revealed that the epidemic was caused by two groups of four isolates each. In both instances the group was geographically contained, and the nursery remained open. A second PFGE analysis indicated that a ninth S. marcescens isolate, recovered in Week 8, was genetically unrelated to the other two. Surveillance during an additional 6 weeks revealed no new cases, and the epidemic was declared over. No cases of invasive S. marcescens infection were identified during the subsequent 10 months. CONCLUSION: Real-time PFGE determined that an apparent nursery outbreak of S. marcescens infection was, in fact, caused by three genetically distinct strains. This information allowed the nursery to remain open after other appropriate infection control measures had been imposed.

Cross Infection↗
PubMed1999

Multidisciplinary team dynamics in the production of problem-based-learning cases in issues related to older adults.

Two important goals in allied health education are to prepare future allied health professionals to function as members of interdisciplinary teams and to increase their awareness of issues related to the growing older adult population. The responsibility for achieving these goals rests on the faculty and administrators of allied health education programs, who may not themselves be proficient in either of these domains. A multidisciplinary team of health educators and administrators was brought together to produce six problem-based learning (PBL) cases related to older adults. Members of the team represented a variety of disciplines in health care, diverse philosophies of educational development, a variety of roles in allied health education, and differing levels of knowledge of issues related to older adults--parameters similar to those found in the members of an interdisciplinary healthcare team. The methods by which this multidisciplinary group functioned and the dynamics in attaining the goals of the project are presented.

Aged↗
PubMed1998

The clinical behavior of localized and multicentric Castleman disease.

BACKGROUND: Castleman disease, an unusual condition of unknown cause consisting of a massive proliferation of lymphoid tissue, remains a clinicopathologic diagnosis. Three histologic variants (hyaline vascular, plasma-cell, and mixed) and two clinical types (localized and multicentric) of Castleman disease have been described. OBJECTIVE: To analyze the clinical features, management, and outcome of patients with Castleman disease. DESIGN: Case series. SETTING: University referral hospitals. PATIENTS: All patients with Castleman disease who were seen at Texas Medical Center, Houston, Texas, between 1977 and 1995. INTERVENTIONS: Surgical excision for localized disease; surgery, combination chemotherapy, or prednisone for multicentric disease. MEASUREMENTS: Patients were identified according to initial presentation as having localized or multicentric Castleman disease. Patients within each group were further subdivided according to whether they had hyaline vascular, plasma-cell, or mixed disease. RESULTS: Data from 15 patients were analyzed. All 7 patients with localized disease underwent surgical excision and remain free of disease. The 8 patients with multicentric disease were further subdivided according to initial treatment: Three patients who received combination chemotherapy are currently alive and free of disease; 2 patients treated with prednisone are alive but have needed intermittent maintenance therapy for disease reactivations; and 2 patients treated with surgery only have died, 1 of infectious complications and 1 of non-Hodgkin lymphoma. CONCLUSIONS: Localized and multicentric Castleman disease are different clinical disorders with overlapping histologic features. Localized disease can be cured with surgery, but complete remissions in patients with multicentric disease have been achieved only with chemotherapy or prednisone given at the time of diagnosis.

Adolescent↗
PubMed1998

Increased von Willebrand factor binding to platelets in single episode and recurrent types of thrombotic thrombocytopenic purpura.

Extensive microvascular platelet aggregation is characteristic of thrombotic thrombocytopenic purpura (TTP). Previous studies have indicated that abnormalities of von Willebrand factor (vWf) are often present in TTP patient plasma. There has not been previously any direct evidence linking these abnormalities to the process of intravascular platelet aggregation in TTP. We used flow cytometry to analyze the binding of vWf to single platelets, and the presence of platelet aggregates, in the blood of 4 children with chronic relapsing (CR) TTP and 5 adults with single episode or recurrent TTP. vWf on the single platelets of CRTTP patients at all time points studied was significantly increased compared to controls, and was increased further as platelet counts decreased to levels below 40,000/microl. The single episode and recurrent adult TTP patients had platelet aggregates in the blood, as well as increased vWf on single platelets, before therapy commenced and thereafter until recovery was in process. In the one unresponsive single episode TTP patient, vWf on single platelets remained elevated, and platelet aggregates persisted, until her death. The platelet alpha-granular protein, P-selectin, was not increased on the single platelets of most TTP blood samples, suggesting that it is vWf from plasma (rather than from alpha-granules) that attaches to platelet surfaces in association with platelet aggregation. These results suggest that vWf-platelet interactions are involved in the platelet clumping process that characterizes TTP.

Adenosine Diphosphate↗
PubMed1998

Endometrial stromal sarcoma of the vulva arising in extraovarian endometriosis: a case report and literature review.

BACKGROUND: Extraovarian malignant transformation of endometriosis is a rare event; 52 cases have been reported. We describe the first published account in the world literature of an endometrial stromal sarcoma (ESS) arising in the vulva from a focus of endometriosis. CASE: A 34-year-old G4 P3 morbidly obese white female was seen with a 1-year history of a palpable lesion arising within the superior aspect of the left labium majus. Radical left hemivulvectomy with clitorectomy was performed. The histopathologic findings were consistent with ESS arising from endometriosis associated with the extrapelvic portion of the round ligament within the canal of Nuck. Twenty months later metatastatic ESS developed in the upper lobe of the right lung and the patient underwent wedge resection. Nine months later she developed a recurrent pulmonary nodule at the site of the previous wedge resection and underwent successful right pulmonary lobectomy. The patient was last seen in October 1995 and had no evidence of disease at that time. CONCLUSIONS: Since approximately 0.7-1.0% of patients with endometriosis have lesions that will ultimately undergo malignant transformation, consideration should be given to bilateral oophorectomy at the time of abdominal surgery in patients with significant endometriosis.

Adult↗
PubMed1998

Prostatectomy tissue for research: balancing patient care and discovery.

The application of modern technology in basic research often requires fresh tissue from human organs. The acquisition of this tissue challenges the anatomic pathologist to balance the needs of the basic scientist with the requirements of quality patient care. Our experience indicates that fresh tissue adequate for research can be obtained from neoplastic prostate glands without compromising patient care. The process requires dedicated, knowledgeable individuals and extensive documentation. Potential problems include low yield for research studies, loss of all residual carcinoma, compromise of the specimen margin, and unforeseen costs. Best collaborations occur in situations in which basic scientists and anatomic pathologists establish a working relationship and develop a mutually supportive means of funding.

Antineoplastic Agents, Hormonal↗
PubMed1997

Neocytolysis: physiological down-regulator of red-cell mass.

It is usually considered that red-cell mass is controlled by erythropoietin-driven bone marrow red-cell production, and no physiological mechanisms can shorten survival of circulating red cells. In adapting to acute plethora in microgravity, astronauts' red-cell mass falls too rapidly to be explained by diminished red-cell production. Ferrokinetics show no early decline in erythropolesis, but red cells radiolabelled 12 days before launch survive normally. Selective destruction of the youngest circulating red cells-a process we call neocytolysis-is the only plausible explanation. A fall in erythropoietin below a threshold is likely to initiate neocytolysis, probably by influencing surface-adhesion molecules. Recognition of neocytolysis will require re-examination of the pathophysiology and treatment of several blood disorders, including the anaemia of renal disease.

Adaptation, Physiological↗
PubMed1997

Increased cytotoxicity and phototoxicity in the methylene blue series via chromophore methylation.

The cytotoxic and photodynamic activities of the commercially-available biological stains methylene blue (MB), 1,9-dimethyl MB (Taylor's Blue) and a newly synthesised compound, 1-methyl MB, were measured against the murine mammary tumour cell line, EMT-6. Both 1-methyl MB and 1,9-dimethyl MB exhibited increased dark toxicity with concomitant higher phototoxicity compared to MB at a light dose of 7.2 J cm-2. While increasing the light dose as a function of the fluence rate increased the photocytotoxicity of MB, this had little effect on the methylated derivatives. In vitro chemical testing proved that successive methylation rendered the phenothiazinium chromophore both more resistant to reduction to its inactive leuco form, and also led to increased levels of singlet-oxygen production, thus providing a possible explanation for the increased toxicities of the methylated derivatives. Comparisons are made with the benzo[a]phenothiazinium photosensitizer, EtNBS.

Animals↗
PubMed1997

Aplastic anemia in eosinophilic fasciitis: responses to immunosuppression and marrow transplantation.

Eosinophilic fasciitis (EF) is a rare connective tissue disorder which is frequently associated with hematologic disorders, especially aplastic anemia (AA) and variants (amegakaryocytic thrombocytopenia). The prognosis for AA with EF has generally been poor, but a few reports suggest a role for immunosuppressive therapy. We have seen four cases of AA complicating EF. All received corticosteroids and anti-thymocyte globulin without any benefit. One patient died of bleeding and infection. A second achieved unmaintained partial remission after two courses of cyclosporine A, although he had difficulty with side effects. Two patients received bone marrow transplants and both initially engrafted well. One had received marrow from a phenotypically HLA-matched parent and died of late graft failure. The second transplanted patient appears to be the only reported case of long term cure of both the AA and EF. Our four patients constitute the largest reported series of AA with EF and shed light on clinical aspects of the disease, and on the pathogenesis, particularly on responsiveness to different therapies; furthermore, there are implications to the treatment of AA in general.

Adolescent↗
PubMed1996

Fatal cerebral venous thrombosis as the initial manifestation of the antiphospholipid syndrome.

We describe a patient with cerebral venous thrombosis (CVT) who presented with thrombocytopenia and persistent headache. The etiology of her CVT was determined to be the antiphospholipid syndrome (APLS) based on a prolonged dilute Russell viper venom test and elevated anti-cardiolipin IgG antibody. CVT has rarely been reported as the initial manifestation of the APLS. Despite supportive measures and anticoagulation, the patient expired. Clinicians should consider the possibility of CVT when coagulation abnormalities consistent with APLS are combined with neurologic symptoms. Early detection and treatment are crucial for a favorable outcome.

Adult↗
PubMed1995

Estrogen replacement therapy and progression of intimal-medial thickness in the carotid arteries of postmenopausal women. ACAPS Investigators. Asymptomatic Carotid Atherosclerosis Progression Study.

The effect of estrogen replacement therapy (ERT) on 3-year changes in carotid intimal-medial thickness (IMT) was explored using serial B-mode ultrasound measurements collected during 1989-1993 as part of the Asymptomatic Carotid Atherosclerotic Progression Study (ACAPS). Eligibility included increased IMT and elevated low density lipoprotein cholesterol. Of the 186 postmenopausal ACAPS women randomly assigned to receive either placebo or lovastatin, 34% reported use of ERT. Users tended to be younger than nonusers by an average of 3 years, to have more favorable high and low density lipoprotein cholesterol levels, and to be more likely to have had hysterectomies. Baseline blood pressure, body mass index, and cross-sectional IMT were similar among ERT users and nonusers. In the placebo group, IMT tended to progress among ERT nonusers but to regress among ERT users: Mean covariate-adjusted progression rates were 0.015 +/- 0.007 mm/year versus -0.012 +/- 0.012 mm/year, respectively (p = 0.05). This difference appeared to be independent of lipoprotein concentrations. Lovastatin was associated with an approximately 25% lowering of low density lipoprotein cholesterol among both ERT users and nonusers and had a marked impact on IMT progression (p = 0.004) in these women. ERT appeared to have little additional effect on IMT in women assigned to lovastatin. ERT may reduce or halt the progression of early atherosclerosis in women not receiving active lipid-lowering medication.

Adult↗
PubMed1994

Coming out, being out, and acts of virtue.

We examine three philosophical models for (gay) self-identity: utilitarianism (exemplified by Eichberg), deontologism (Mohr), and individualism (Spinoza). The first two, we argue, overlook the personal and multi-faceted nature of social relations. We argue that the framework of methodological individualism is better suited to deal with the issues of self-identity as they affect questions of whether, when, and how to come out, and being out. This framework suggests that there is no moral principle which could apply universally in regard to being out and that there are common situations in which it is not morally appropriate to come out or to be out at all.

Female↗