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Biomedical subjects

S Fisher

Publications and source records attributed to S Fisher.

At least 37 records · Page 2Linked to original sources
PubMed2001

Pilot study of sequential vinorelbine and cisplatin followed by docetaxel for selected IIIB and stage IV non-small cell lung cancer.

UNLABELLED: Vinorelbine, cisplatin and docetaxel are known to be efficacious in non-small cell lung cancer (NSCLC). This limited institution pilot study evaluated the novel strategy of sequencing active first line agents prior to progression. The primary objective of this study was to assess the toxicity profile in anticipation of a larger cooperative group standard phase II study. Patients with selected stage IIIB and IV NSCLC, Southwest Oncology Group (SWOG) performance status (PS) of 1 or less and measurable or evaluable disease were eligible. Treatment was cisplatin 100 mg/m(2) day 1 and 29, vinorelbine 25 mg/m(2) weekly for 8 weeks, followed by docetaxel 100 mg/m(2) every 21 days for four cycles if no progression. If grade IV neutropenia developed, G-CSF 5 mcg/kg/day was used in subsequent cycles. Of 18 eligible patients, 17 patients had stage IV disease with a median age of 66 years (range 48-80). Eight patients had a SWOG PS of 1, 10 had a PS of zero. Six of eighteen patients received all 8 weeks of vinorelbine/cisplatin and six of eight patients who went on to receive docetaxel received all four planned cycles; only two patients overall received all planned therapy. One grade III/IV event each of cardiotoxicity (myocardial infarction), renal toxicity (acute renal failure), anemia and thrombocytopenia occurred with vinorelbine and cisplatin, and 2 Grade IV hypersensitivity reactions, manifested by severe back pain with docetaxel occurred. Three deaths occurred during the study, all during treatment with vinorelbine and cisplatin: one due to neutropenic sepsis; one from a pulmonary embolism; and one secondary to severe hypoglycemia in a diabetic patient. Of the 16 patients evaluable for response after vinorelbine/cisplatin, there were two complete responses (12.5%) and three partial responses (19%) for an overall response rate of 31% (95% CI 8-58). One additional patient who received docetaxel experienced a partial response. Two patients remain alive (21+ and 18+ months, respectively). The 1-year survival was 44%. CONCLUSION: This sequence, as defined, was tolerated marginally well in patients with advanced NSCLC. Granulocytopenia was the major toxicity requiring dose adjustments throughout the sequence. Based on response rates and tolerability that were somewhat comparable to other regimens in this disease setting, a modified version of this program, adjusted to decrease the incidence of grade III and IV toxicity, was selected as one arm of a recent randomized phase II trial in the Southwest Oncology Group (SWOG), S9806, evaluating sequential therapy in advanced NSCLC.

Acute Kidney Injury↗
PubMed2001

IL-12, TNF-alpha, and hormonal changes during late pregnancy and early postpartum: implications for autoimmune disease activity during these times.

Clinical observations indicate that some autoimmune diseases, such as rheumatoid arthritis and multiple sclerosis, frequently remit during pregnancy but exacerbate, or have their onset, in the postpartum period. The immune basis for these phenomena is poorly understood. Recently, excessive production of IL-12 and TNF-alpha was causally linked to rheumatoid arthritis and multiple sclerosis. We studied 18 women with normal pregnancies in their third trimester and during the early postpartum period. We report that during the third trimester pregnancy, ex vivo monocytic IL-12 production was about 3-fold and TNF-alpha production was approximately 40% lower than postpartum values. At the same time, urinary cortisol and norepinephrine excretion and serum levels of 1,25-dihydroxyvitamin were 2- to 3-fold higher than postpartum values. As shown previously, these hormones can directly suppress IL-12 and TNF-alpha production by monocytes/macrophages in vitro. We suggest that a cortisol-, norepinephrine-, and 1,25-dihydroxyvitamin-induced inhibition and subsequent rebound of IL-12 and TNF-alpha production may represent a major mechanism by which pregnancy and postpartum alter the course of or susceptibility to various autoimmune disorders.

Adult↗
PubMed2001

Lack of ignorance to tumor antigens: evaluation using nominal antigen transfection and T-cell receptor transgenic lymphocytes in Lyons-Parish analysis--implications for tumor tolerance.

A substantial body of literature has described weak antitumor CTL responses in tumor-bearing hosts, and a number of authors have suggested that tumor tissue in some way sequesters antigen from the immune system, a failure of the tumor-specific immune response largely attributable to "ignorance." To evaluate this in a tumor model, we stably transfected murine tumor cell lines with genes coding for the nominal antigens influenza hemagglutinin (HA) or ovalbumin (OVA) and adoptively transferred HA- or OVA-specific T-cell receptor-transgenic, CD8-positive T cells into mice-bearing these tumors. Tumor antigen cross-presentation within draining lymph nodes (LNs) was then examined using Lyons-Parish analysis, detection of a proliferative response of 5,6-carboxyfluorescein diacetate succinimidyl ester-labeled CD8 T cells from T-cell receptor mice using flow cytometric analysis. Our studies demonstrate clearly that tumor antigens are constitutively presented in LNs draining tumors and can stimulate a T-cell proliferative response. This lack of ignorance was not simply attributable to the model chosen, because it was seen with three different cell lines, two different antigens, and two different mouse strains. Furthermore, it occurred regardless of whether these tumor antigens were expressed as cytoplasmic, transmembrane, or secreted proteins. When tumor antigens were present in low concentrations, antigen cross-presentation was not absent but simply delayed. Interestingly, tumor antigen cross-presentation remained localized to the LNs draining the tumor throughout the period of tumor growth. Curiously, in animals where tumors failed to grow, evidence of continued cross-presentation of the tumor antigen was seen up to 6 months after tumor inoculation. These data suggest that ignorance is not an explanation for the failure of the host immune system to respond to tumor antigens.

Animals↗
PubMed2000

Positron emission tomography scanning in malignant melanoma.

BACKGROUND: Several recent studies have demonstrated the low yield of anatomically based computed tomography scans in evaluating Stage III (American Joint Committee on Cancer) patients with malignant melanoma. The purpose of this study was to investigate the efficacy and clinical utility of functionally based positron emission tomography (PET) scans in the same patient population. METHODS: A prospective evaluation of 106 whole body PET scans obtained after injection of 2-fluorine-18, 2-fluoro-2-deoxy-D-glucose (FDG) was performed in 95 patients with clinically evident Stage III lymph node and/or in-transit melanoma. Areas of abnormality on FDG PET scanning were identified visually as foci of increased metabolic activity compared with background, and all positive foci were assessed pathologically. RESULTS: In this patient population, there were 234 areas that were evaluated pathologically of which 165 were confirmed histologically to be melanoma. PET scanning identified 144 of the 165 areas of melanoma for a sensitivity of 87.3%. The 21 areas of melanoma that were missed included 10 microscopic foci, 9 foci less than 1 cm, and 2 foci greater than 1 cm. There were 39 areas of increased PET activity that were not associated with malignancy for a 78.6% predictive value of a positive test. Of the 39 false-positive areas (false-positive rate of 56.5%), 13 could be attributed to recent surgery, 3 to arthritis, 3 to infection, 2 to superficial phlebitis, 1 to a benign skin nevus, and 1 to a colonic polyp. Pathologic evaluation of the remaining false-positive areas failed to reveal a definitive etiology for their increased activity on PET scan. With the application of pertinent clinical information, the predictive value of a positive PET scan could be improved to 90. 6%. The specificity of PET scanning in this study was only 43.5% because very few prophylactic lymph node dissections were performed. Thirty-six of the total 183 abnormal areas (19.7%) on PET scanning proved to be unsuspected areas of metastatic disease. These findings led to a change in the planned clinical management in patients after 16 of the 106 PET scans (15.1%). CONCLUSIONS: FDG PET scanning can be helpful in managing patients with Stage III melanoma in whom further surgery is contemplated. Although false-positive areas are not uncommon, PET scans did change the management of patients 15% of the time. PET's inability to identify microscopic disease suggests that it is of limited use in evaluating patients with Stage I-II disease.

Fluorodeoxyglucose F18↗
PubMed2000

Radioimmunotherapy with iodine (131)I tositumomab for relapsed or refractory B-cell non-Hodgkin lymphoma: updated results and long-term follow-up of the University of Michigan experience.

CD20-targeted radioimmunotherapy is a promising new treatment for B-cell non-Hodgkin lymphoma (NHL). We now provide updated and long-term data on 59 chemotherapy-relapsed/refractory patients treated with iodine (131)I tositumomab in a phase I/II single-center study. Fifty-three patients received individualized therapeutic doses, delivering a specified total-body radiation dose (TBD) based on the clearance rate of a preceding dosimetric dose. Six patients received dosimetric doses only. Dose-escalations of TBD were conducted separately in patients who had or had not undergone a prior autologous stem cell transplant (ASCT) until a nonmyeloablative maximally tolerated TBD was established (non-ASCT = 75 cGy, post-ASCT = 45 cGy). Fourteen additional non-ASCT patients were treated with 75 cGy. Unlabeled antibody was given prior to labeled dosimetric and therapeutic doses to improve biodistribution. Forty-two (71%) of 59 patients responded; 20 (34%) had complete responses (CR). Thirty-five (83%) of 42 with low-grade or transformed NHL responded versus 7 (41%) of 17 with de novo intermediate-grade NHL (P =.005). For all 42 responders, the median progression-free survival was 12 months, 20.3 for those with CR. Seven patients remain in CR 3 to 5.7 years. Sixteen patients were re-treated after progression; 9 responded and 5 had a CR. Reversible hematologic toxicity was dose limiting. Only 10 patients (17%) had human anti-mouse antibodies detected. Long-term, 5 patients developed elevated thyroid-stimulating hormone levels, 5 were diagnosed with myelodysplasia and 3 with solid tumors. A single, well-tolerated treatment with iodine (131)I tositumomab can, therefore, produce frequent and durable responses in NHL, especially low-grade or transformed NHL. (Blood. 2000;96:1259-1266)

Adult↗
PubMed2000

Human nerve growth factor protects common marmosets against autoimmune encephalomyelitis by switching the balance of T helper cell type 1 and 2 cytokines within the central nervous system.

Multiple sclerosis is a demyelinating disorder of the central nervous system (CNS), in which an immune attack directed against myelin constituents causes myelin destruction and death of oligodendrocytes, the myelin-producing cells. Here, the efficacy of nerve growth factor (NGF), a growth factor for neurons and oligodendrocytes, in promoting myelin repair was evaluated using the demyelinating model of experimental allergic encephalomyelitis (EAE) in the common marmoset. Surprisingly, we found that NGF delayed the onset of clinical EAE and, pathologically, prevented the full development of EAE lesions. We demonstrate by immunocytochemistry that NGF exerts its antiinflammatory effect by downregulating the production of interferon gamma by T cells infiltrating the CNS, and upregulating the production of interleukin 10 by glial cells in both inflammatory lesions of EAE and normal-appearing CNS white matter. Thus, NGF, currently under investigation in human clinical trials as a neuronal trophic factor, may be an attractive candidate for therapy of autoimmune demyelinating disorders.

Animals↗
PubMed2000

Comparative analysis of DNA flow cytometry and cytology of bladder washings: review of discordant cases.

DNA analysis is becoming an important diagnostic and prognostic adjunct test in urinary cytology. The aim of this study was to compare the results of DNA flow cytometry (FCM) with the cytologic diagnosis of bladder washings (BW). DNA ploidy was evaluated in 251 BW. In 65 cases, follow-up surgical biopsies were available. Cytology results were classified as positive and negative, and FCM results were categorized as diploid and aneuploid. Both tests were evaluated independently. Cases were defined as discordant if the cytology was negative and FCM was aneuploid, or if the cytology was positive and FCM was diploid. All discordant cases were reviewed, and positive predictive values (PPV) for FCM and cytology were calculated for cases with follow-up biopsy results. Cytologic evaluation classified 181 cases as negative, with 175 of them diploid and 6 aneuploid; and 70 as positive, with 53 of them diploid and 17 aneuploid. Overall, there were 59 discordant cases (23.5%, with a confidence limit of 18.2-28.8%). Of 6 aneuploid/cytology-negative cases, biopsies were available in 4 cases and showed one grade 1, two grade 2, and one grade 3 urothelial carcinoma (UC). Reanalysis of these 6 cytology specimens showed 1 case that should have been interpreted as positive (false negative), 4 true negatives, and 1 polyoma virus infection. Out of 53 diploid/cytology-positive cases, biopsies were available in 45 cases and showed nine grade 1, 14 grade 2, three grade 3 UCs, 11 UCs in situ, and eight negative biopsies. The PPV for cytology was 85%, and the PPV for FCM was 95%. We concluded that FCM, which requires a large number of cells, often cannot detect small aneuploid populations, which are present particularly in cases of UC in situ.

Adult↗
PubMed2000

HLA-G, -E, -F preworkshop: tools and protocols for analysis of non-classical class I genes transcription and protein expression.

Non-classical MHC class I HLA-E, -F, and -G molecules differ from classical class I histocompatibility antigens by specific patterns of transcription, protein expression, and immunological functions. Restriction of the expression pattern of these non-classical antigens may play a key role in modulation of immune responses during pregnancy and diseases but remains to be additionally defined. A specific component of the second International Conference on HLA-G and the 13th HLA-G Histocompatibility Workshop will be dedicated to the analysis of transcription and expression of non-classical class I genes in normal and pathological tissues. In a first step, referred to as the preworkshop, we here report the analysis and conclusions of a working group which was constituted to gather and validate optimal reagents and protocols allowing RT-PCR analysis of HLA-E, -F, -G transcript levels and flow cytometry and immunochemistry analysis of HLA-G expression in cells and tissues. As a result of this work, use of specific primers and probes detecting alternative transcripts of HLA-E, -F, and G have been validated in transfected cells expressing differential pattern of HLA class I antigens. Analysis of the specificity and affinity of collected antibodies has allowed definition of reagents to be proposed for immunochemistry and flow cytometry analysis of HLA-G expression in normal and pathological tissues during the workshop. This work has allowed constitution of an extended workshop group which is now initiating analysis of non-classical class I transcription and expression in various cells and tissues, a collective contribution that will additionally refine our view of the expression of these antigens in normal and pathological situations.

Antibodies, Monoclonal↗
PubMed2000

Developing the DSM-IV-DSM-IV criteria to identify adolescent problem gambling in non-clinical populations.

This paper presents a revised version of DSM-IV-J criteria for youth, the DSM-IV-MR-J, together with psychometric data stemming from its use in a major prevalence study of adolescent gambling and problem gambling. The case is made for further development and testing of current and emerging instruments to screen for problem gambling in youth, with the aim of establishing one internationally accepted gold standard measure.

Journal Article↗
PubMed2000

Measuring the prevalence of sector-specific problem gambling: a study of casino patrons.

This study is the first attempt to measure the prevalence of problem gambling attributable to a specific sector of the gambling industry. One thousand, one hundred and five casino patrons in 40 casinos in the UK were interviewed, face-to-face. Respondents were screened for problem gambling using a multiple response version of DSM-IV (DSM-IV-MR). The study found support for Eadington's (1988) hypothesis, that UK casinos could be largely sustained by regular players, among whom the prevalence of problem gambling is high. The study also found support for the hypothesis that, to the extent different gambling sectors are patronised by demographically different client groups, so the problem gamblers associated with them will reflect these client groups. The problem gamblers among the regular casino patrons were demographically distinct from the problem gamblers in the sample who showed a preference for other gambling forms. Other key findings support those found in other jurisdictions. Sector-specific prevalence studies may be the next step forward in epidemiological research on problem gambling. They have the major advantage of netting significantly more problem gamblers from much smaller samples than similar studies in the general population. They also have the potential to reveal the proportion of problem gamblers attributable to each sector, along with their demographic characteristics. Such information would result in more specific information being available for regulators seeking to minimise the social impact of problem gambling and those involved in the development of prevention and treatment strategies.

Journal Article↗
PubMed2000

Lack of human leukocyte antigen-G expression in extravillous trophoblasts is associated with pre-eclampsia.

Pre-eclampsia, a common complication of first pregnancies, is thought to result from a poorly perfused placenta and may reflect an abnormal maternal immune reaction to the hemiallogenic fetus. Human leukocyte antigen (HLA)-G, a major histocompatibility tissue-specific antigen expressed in extravillous trophoblast cells (fetal-derived), may protect trophoblasts from maternal-fetal immune intolerance and allow these cells to invade the uterus. Through RNA in-situ hybridization analysis, we studied the expression pattern of HLA-G in normal placentae and placentae from pregnancies complicated by severe pre-eclampsia. In normal placenta we found HLA-G expression in the anchoring extravillous trophoblasts with an increasing gradient of expression in the more invasive cells. However, in nine out of 10 pre-eclamptic placentae HLA-G expression was absent or reduced. We conclude that HLA-G is normally expressed in invasive trophoblasts and HLA-G expression is defective in most pre-eclamptic placentae. We propose that trophoblasts lacking HLA-G are vulnerable to attack by the maternal immune system. These defective trophoblasts will be unable to invade the maternal spiral arteries effectively, thereby developing vessels which cannot adequately nourish the developing placenta. This poorly perfused placenta may initiate the systemic cascade of events associated with pre-eclampsia.

Female↗
PubMed2000

Human cytomegalovirus infection of placental cytotrophoblasts in vitro and in utero: implications for transmission and pathogenesis.

Human cytomegalovirus (CMV) is the leading cause of prenatal viral infection. Affected infants may suffer intrauterine growth retardation and serious neurologic impairment. Analysis of spontaneously aborted conceptuses shows that CMV infects the placenta before the embryo or fetus. In the human hemochorial placenta, maternal blood directly contacts syncytiotrophoblasts that cover chorionic villi and cytotrophoblasts that invade uterine vessels, suggesting possible routes for CMV transmission. To test this hypothesis, we exposed first-trimester chorionic villi and isolated cytotrophoblasts to CMV in vitro. In chorionic villi, syncytiotrophoblasts did not become infected, although clusters of underlying cytotrophoblasts expressed viral proteins. In chorionic villi that were infected with CMV in utero, syncytiotrophoblasts were often spared, whereas cytotrophoblasts and other cells of the villous core expressed viral proteins. Isolated cytotrophoblasts were also permissive for CMV replication in vitro; significantly, infection subsequently impaired the cytotrophoblasts' ability to differentiate and invade. These results suggest two possible routes of CMV transmission to the fetus: (i) across syncytiotrophoblasts with subsequent infection of the underlying cytotrophoblasts and (ii) via invasive cytotrophoblasts within the uterine wall. Furthermore, the observation that CMV infection impairs critical aspects of cytotrophoblast function offers testable hypotheses for explaining the deleterious effects of this virus on pregnancy outcome.

Cells, Cultured↗
PubMed2000

Selected contribution: mechanical strain increases force production and calcium sensitivity in cultured airway smooth muscle cells.

Cultured airway smooth muscle cells subjected to cyclic deformational strain have increased cell content of myosin light chain kinase (MLCK) and myosin and increased formation of actin filaments. To determine how these changes may increase cell contractility, we measured isometric force production with changes in cytosolic calcium in individual permeabilized cells. The pCa for 50% maximal force production was 6.6+/-0.4 in the strain cells compared with 5.9+/-0.3 in control cells, signifying increased calcium sensitivity in strain cells. Maximal force production was also greater in strain cells (8.6+/-2.9 vs. 5.7+/-3.1 microN). The increased maximal force production in strain cells persisted after irreversible thiophosphorylation of myosin light chain, signifying that increased force could not be explained by differences in myosin light chain phosphorylation. Cells strained for brief periods sufficient to increase cytoskeletal organization but insufficient to increase contractile protein content also produced more force, suggesting that strain-induced cytoskeletal reorganization also increases force production.

Actins↗
PubMed2000

Collaboration between general practitioners and a child and adolescent mental health service.

OBJECTIVE: The aim of this project was to develop a collaborative working relationship between general practitioners and a child and adolescent mental health service (CAMHS). METHODS: The project focused on changing the policies and culture within CAMHS to be more GP aware and inclusive. The project also provided GPs with an accredited training package on common mental health problems. The impact of the project was determined through pre and post project surveys and interviews with GPs and mental health workers (case managers) respectively. RESULTS: There was a two-fold increase in communication between the two sectors and a 120% increase in shared care arrangements. There was a 144% improvement in GPs' perceptions of the helpfulness of public CAMHS. DISCUSSION: Implications for future collaboration are discussed. The results of this pilot study are encouraging and warrant replication and validation using standardised instruments. CONCLUSION: To create, enhance and extend the working relationships between GPs and public CAMHS requires strategies for change in both sectors.

Adolescent↗
PubMed1999

Beta-secretase cleavage of Alzheimer's amyloid precursor protein by the transmembrane aspartic protease BACE.

Cerebral deposition of amyloid beta peptide (Abeta) is an early and critical feature of Alzheimer's disease. Abeta generation depends on proteolytic cleavage of the amyloid precursor protein (APP) by two unknown proteases: beta-secretase and gamma-secretase. These proteases are prime therapeutic targets. A transmembrane aspartic protease with all the known characteristics of beta-secretase was cloned and characterized. Overexpression of this protease, termed BACE (for beta-site APP-cleaving enzyme) increased the amount of beta-secretase cleavage products, and these were cleaved exactly and only at known beta-secretase positions. Antisense inhibition of endogenous BACE messenger RNA decreased the amount of beta-secretase cleavage products, and purified BACE protein cleaved APP-derived substrates with the same sequence specificity as beta-secretase. Finally, the expression pattern and subcellular localization of BACE were consistent with that expected for beta-secretase. Future development of BACE inhibitors may prove beneficial for the treatment of Alzheimer's disease.

Alzheimer Disease↗
PubMed1999

The role of splenic irradiation in treating HIV-associated immune thrombocytopenia.

PURPOSE: To evaluate our experience in treating patients with HIV-associated thrombocytopenia using splenic irradiation. METHODS AND MATERIALS: From 1993 to 1998, 10 patients with HIV-related immune thrombocytopenia (ITP) were treated in our department with low-dose splenic irradiation. All patients had either failed more conventional treatment modalities or possessed some contraindication to them. RESULTS: Nine of 10 patients had at least a small, transient rise in their platelet counts, but only two received a substantial therapeutic benefit. Of these two, one died shortly after completing his course of radiation therapy while the other maintained near normal platelet counts up to approximately 3(1/2) years following treatment. There were no treatment-related morbidities and one patient was treated twice. CONCLUSION: While most patients with HIV-associated ITP may initially respond favorably to splenic irradiation with small rises in platelet count, few responses are likely to be sustained or provide clinically significant outcomes. Our results support those previously reported by others treating this same condition. What remains to be investigated is whether there are any prognostic indicators to help identify those patients most likely to respond to this treatment, thus enabling us to reserve splenic irradiation for those who might derive a substantial benefit from it.

Adult↗