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Biomedical subjects

L Sutton

Publications and source records attributed to L Sutton.

At least 37 records · Page 2Linked to original sources
PubMed1998

Folate, vitamin B12, and serum total homocysteine levels in confirmed Alzheimer disease.

BACKGROUND: Recent studies suggest that vascular disease may contribute to the cause of Alzheimer disease (AD). Since elevated plasma total homocysteine (tHcy) level is a risk factor for vascular disease, it may also be relevant to AD. OBJECTIVE: To examine the association of AD with blood levels of tHcy, and its biological determinants folate and vitamin B12. DESIGN: Case-control study of 164 patients, aged 55 years or older, with a clinical diagnosis of dementia of Alzheimer type (DAT), including 76 patients with histologically confirmed AD and 108 control subjects. SETTING: Referral population to a hospital clinic between July 1988 and April 1996. MAIN OUTCOME MEASURES: Serum tHcy, folate, and vitamin B12 levels in patients and controls at entry; the odds ratio of DAT or confirmed AD with elevated tHcy or low vitamin levels; and the rate of disease progression in relation to tHcy levels at entry. RESULTS: Serum tHcy levels were significantly higher and serum folate and vitamin B12 levels were lower in patients with DAT and patients with histologically confirmed AD than in controls. The odds ratio of confirmed AD associated with a tHcy level in the top third (> or = 14 micromol/L) compared with the bottom third (< or = 11 micromol/L) of the control distribution was 4.5 (95% confidence interval, 2.2-9.2), after adjustment for age, sex, social class, cigarette smoking, and apolipoprotein E epsilon4. The corresponding odds ratio for the lower third compared with the upper third of serum folate distribution was 3.3 (95% confidence interval, 1.8-6.3) and of vitamin B12 distribution was 4.3 (95% confidence interval, 2.1-8.8). The mean tHcy levels were unaltered by duration of symptoms before enrollment and were stable for several years afterward. In a 3-year follow-up of patients with DAT, radiological evidence of disease progression was greater among those with higher tHcy levels at entry. CONCLUSIONS: Low blood levels of folate and vitamin B12, and elevated tHcy levels were associated with AD. The stability of tHcy levels over time and lack of relationship with duration of symptoms argue against these findings being a consequence of disease and warrant further studies to assess the clinical relevance of these associations for AD.

Aged↗
PubMed1998

Emergent/urgent therapeutic irradiation in pediatric oncology: patterns of presentation, treatment, and outcome.

PURPOSE: We reviewed all pediatric cases referred for emergent/urgent therapy (requiring treatment within 48 hours) to identify frequency, patterns of presentation, and efficacy of therapy. We defined five categories of emergent/urgent therapy based on irradiated site and/or signs: Group I, spinal cord compression; Group II, respiratory compromise; Group III, infradiaphagmatic distress; Group IV, intracranial signs; Group V, pain. MATERIALS AND METHODS: From 2/1/88-3/1/ 94, 104 children with 115 problems were referred by specialists at the Children's Hospital of Philadelphia. Diagnosis, nature of the emergency, and response were examined. Responses were categorized as complete resolution, improvement or stabilization, and progression. RESULTS: The 104 children represented 12% of referrals during the study period. The most common tumors were CNS PNET and gliomas (20%); and neuroblastoma (20%). Forty-five problems occurred with newly diagnosed tumors and 70 after progression. Ninety-one episodes were managed with radiation therapy and 24 with other modalities. Patients with spinal cord/cauda equina (n = 33) compression improved (55%) or stabilized (30%). Patients with respiratory compromise from thoracic (n = 14) or abdominal (n = 5) disease had a response rate of 72%. Eight patients in group III had a 66% response. In Group IV (n = 16), 63% had complete responses and 19% had stabilization. Group V (n = 15) patients had a complete or partial response of 93%. CONCLUSION: Approximately 10% of children referred for radiation therapy required emergent/urgent treatment. Eighty percent of patients achieved stabilization or showed improvement in signs and symptoms, indicating that radiotherapy is a valuable and reliable component of multimodal care in such situations.

Adolescent↗
PubMed1998

Pulmonary blood flow measured by inspiratory inert gas concentration forcing oscillations.

The aim of this study was to discover if the forced inspired inert gas sinewave technique could be used to measure pulmonary blood flow, using nitrous oxide as the indicator gas, following inotropic stimulation of the heart by dobutamine, in the presence of a constant alveolar ventilation. Cardiac output (range 1-4.5 L min(-1)) was measured in six dogs by thermodilution and by calculation from the sinusoidal expired partial pressures of argon and nitrous oxide using: (i) analytical equations and a conventional continuous ventilation three-compartment lung model, which did not include recirculation; and (ii) a digital simulation tidal ventilation lung model (Gavaghan and Hahn, 1996. Respir. Physiol. 106, 209-221) which was adapted to include nitrous oxide mixed-venous recirculation from a combined single viscera compartment. The continuous ventilation model calculations always underestimated thermodilution cardiac output, with the bias error increasing to almost -1 L min(-1) at the longest forcing periods, 4-5 min. In contrast, the tidal ventilation model calculations were in close agreement to thermodilution cardiac output, with biases of -0.04 and -0.26 L min(-1) at forcing periods of 2 and 3 min, respectively.

Administration, Inhalation↗
PubMed1998

Autologous hematopoietic stem cell transplantation as salvage treatment for advanced B cell chronic lymphocytic leukemia.

Given the generally poor outcome of advanced B cell chronic lymphocytic leukemia, experimental approaches are warranted, especially for younger patients in whom classical treatments have failed. We therefore conducted a prospective single-center study, using polychemotherapy (ESHAP) to prepare patients for hematopoietic stem cell collection and autologous stem cell transplantation as consolidation therapy. Twenty patients entered the study. An adequate response to ESHAP was obtained in 13 patients, and sufficient stem cells for grafting were obtained in eight of the 12 patients who underwent the collection procedure. Six of these grafted patients are alive in complete clinical remission a median of 30 months after transplantation. It should be noted that we were only able to graft 40% of the patients enrolled in this study, either because a new remission could not be obtained or because not enough hematopoietic stem cells could be collected. This argues for stem cell collection as soon as a first remission is obtained, even if the autograft is done later in the course of the disease.

Adult↗
PubMed1998

CCR5/delta(ccr5) heterozygosity: a selective pressure for the syncytium-inducing human immunodeficiency virus type 1 phenotype. NIAID AIDS Clinical Trials Group Protocol 241 Virology Team.

Mechanisms underlying the delay in dominance of syncytium-inducing (SI) phenotype HIV-1 (human immunodeficiency virus type 1) in vivo are unknown. Both random mutational events and selective pressures operative only late in the disease process have been suggested to underlie the shift from CCR5 to alternative coreceptor usage. Among the moderately advanced patients who entered AIDS Clinical Trials Group protocol 241, SI viral phenotype was more common among CCRS/delta(ccr5) heterozygotes (7/7, 100%) than among CCR5/CCR5 homozygotes (29/88, 33%; P < .001, Fisher's exact test). Other characteristics did not differ at study entry by CCR5 genotype, including median CD4 cell counts, plasma RNA levels, and infectious HIV-1 titers in circulating cells. These data indicate that CCR5/delta(ccr5) heterozygosity, which decreases cell-surface levels of CCR5 available to serve as an HIV-1 entry coreceptor, is a selective pressure for evolution of T cell line-tropic viruses that use an alternative coreceptor.

Adult↗
PubMed1998

Synergistic cytotoxicity of topoisomerase I inhibitors with alkylating agents and etoposide in human brain tumor cell lines.

To evaluate potential synergistic interactions between topoisomerase I (Topo I) inhibitors, i.e. camptothecin (CPT) and topotecan (TPT), and chemotherapeutic agents known to be active in treatment of brain tumors, in vitro studies were conducted with human glioma and medulloblastoma cell lines. Tumor cells were exposed to CPT or TPT alone or in combination with cisplatin, 4-hydroperoxycyclophosphamide (4-HC), BCNU or etoposide (VP-16). Cytotoxicity was assessed by colony formation assays. Drug interactions were evaluated by means of a novel analytical model which permits statistical evaluation over a range of dose combination. Experimental results were corroborated by published models of drug interaction. Our findings indicate that in vitro cytotoxic interactions in brain tumor cells between Topo I inhibitors and alkylating agents or etoposide depend on drug dose, dose schedule and tumor cell line. Treatment of DAOY medulloblastoma cells with CPT and either cisplatin, 4-HC or VP-16 produced significant synergistic cytotoxicity over a wide range of dose combinations. When VP-16 was administered after CPT, synergy was reduced to a narrow range of dose combinations. For U251 glioma cells, incubation with CPT and cisplatin or 4HC also produced synergistic cytotoxicity over a broad range of dose combinations. By contrast, antagonistic interactions were observed after administration of CPT with BCNU or VP-16. Treatment of U251 cells with CPT and cisplatin produced synergistic or antagonistic cytotoxicity depending on the dose combination used. These findings support a role for pharmacokinetic analysis in multiagent phase 11 trials involving Topo I inhibitors and have important implications for clinical trial design strategies.

Antineoplastic Agents↗
PubMed1998

Posttransplant lymphoproliferative disorders not associated with Epstein-Barr virus: a distinct entity?

PURPOSE: Organ recipients are at a high risk of posttransplant lymphoproliferative disorders (PTLD) as a result of immunosuppressive therapy. Most B-cell lymphomas are associated with Epstein-Barr virus (EBV) infection. We describe a morphologically and clinically distinct group of PTLD in 11 patients that occurred late after organ transplantation and were not associated with EBV. PATIENTS AND METHODS: There were seven kidney, three heart, and one liver transplant recipients (group I). The clinical manifestations, pathologic findings, treatment, and outcome were compared with those in 21 patients with EBV-associated PTLD treated in our institution (group II). EBV was detected with at least two techniques: Epstein-Barr-encoded RNA (EBER) in situ hybridization with EBER 1 + 2 probes, Southern blotting, and detection of latent membrane protein 1 (LMP1) expression by immunohistochemistry. RESULTS: The time between transplantation and the diagnosis of lymphoma ranged from 180 to 10,220 days in group I (mean, 2,234; median, 1,800) and from 60 to 2,100 days in group II (mean, 546; median, 180), and was significantly shorter in group II (P = .02). Among 19 tumors diagnosed within 2 years after the graft, 16 were associated with EBV; among 13 tumors diagnosed after more than 2 years, only five were associated with EBV. All of the B-cell PTLDs in group I were classified as monomorphic, meeting the criteria of B diffuse large-cell lymphoma (B-DLCL) with a component of immunoblasts, and genotyping confirmed their monoclonality. Three tumors were T-cell pleomorphic lymphomas. Tumor sites were mainly bone marrow and lymph nodes. Overall median survival was 1 month in group I and 37 months in group II, with two patients still alive in group I and nine in group II. The survival time was significantly longer in group II (P < .01). CONCLUSION: EBV-negative PTLD may be a late serious complication of organ transplantation. Half the tumors observed after kidney transplantation in our center were not associated with EBV and emerged after more than 5 years, which suggests the number of EBV-negative PTLDs in organ recipients might increase with time.

Adolescent↗
PubMed1998

Severe autoimmune hemolytic anemia in eight patients treated with fludarabine.

We have used fludarabine to treat 36 patients with various lymphoid malignancies, including 29 with chronic lymphocytic leukemia (CLL). All these patients were heavily pretreated, and FAMP was prescribed on a compassionate basis. Eight patients (22%) developed severe autoimmune hemolytic anemia (AIHA) during or after treatment, and one died. Five patients had no previous history of hemolysis. These cases confirm the high incidence of AIHA after FAMP and suggest that the use of highly effective lymphocytotoxic agents such as fludarabine in heavily pretreated patients increases the risk of AIHA in CLL and other lymphoproliferative disorders.

Aged↗
PubMed1997

Expansion of CD4+CD7- T cells, a memory subset with preferential interleukin-4 production, after bone marrow transplantation.

BACKGROUND: Inadequate reconstitution of CD4+ lymphocyte and interleukin (IL)-2 production defect are observed after bone marrow or peripheral blood stem cell transplantation (SCT). METHODS: We studied immune reconstitution after SCT in 33 consecutive patients who received allogeneic SCT (17 patients) or autologous SCT (16 patients). The aims were to assess the regeneration of the CD4+ T-cell subset with regard to helper cell differentiation. CD4+ T-cell subset regeneration and expansion of the CD4+CD7- subset were studied by immunofluorescence analysis. CD4+CD7- cell cytokine secretion was analyzed after cell sorting and costimulation of the CD3 and CD28 pathways, in enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction assays. RESULTS: We report a relative expansion of the CD4+CD7- subset within CD4+ T cells, detected as early as 1 month after bone marrow transplantation and decreasing after day 60. CD4+CD7- T cells preferentially expressed CD45RO and activation markers such as CD57, CD25, and HLA-DR. No relationship was observed between the CD4+CD7- expansion and transplant-related complications. We observed no significant IL-2 production in supernatants from sorted CD4+CD7- T cells, whereas IL-4 levels were comparable to those produced by cells from normal individuals. Autologous CD4+CD7+ cells showed little, if any, IL-4 production, and IL-2 production was lower than that by normal CD4+CD7+ T cells. Reverse transcription-polymerase chain reaction assays showed similar amounts of interferon-gamma transcripts in the two subsets; tumor necrosis factor-alpha, IL-4, and IL-10 transcripts were detected in CD4+CD7- T cells but not in their CD4+CD7+ counterparts. CONCLUSIONS: These data confirm the IL-2 production defect after bone marrow transplantation and suggest that the CD4+CD7- T-cell subset might be preferentially involved in the enhanced production of IL-4 and low production of IL-2. These data show that the early immune reconstitution in CD4+ T cells after SCT preferentially involves memory T cells with a Th0/Th2 differentiation that might participate in the T-helper cell defect.

Adult↗
PubMed1997

Early onset of immunoglobulin heavy chain gene rearrangements in normal human bone marrow CD34+ cells.

To characterize early B-cell precursors in humans, we correlated immunoglobulin heavy chain (IgH) gene rearrangement status with the CD34, CD19, and CD10 cell surface markers. Highly purified adult bone marrow (BM) cell fractions were obtained by two successive rounds of flow cytometric cell sorting, and IgH rearrangements were analyzed by polymerase chain reaction (PCR) amplification. Complete VDJH rearrangements were observed in the CD34+ CD19+ fraction, but not in the more immature CD34+ CD19- fraction. About one quarter of these rearrangements had an open reading frame, thus potentially permitting the synthesis of a mu chain. Partial DJH rearrangements were detected in both CD34+ CD19+ and CD34+ CD19- subsets, although they were less abundant in the latter. When triple labeling was used to better characterize the CD34+ CD19- population, DJH rearrangements were found to be present in the CD34(+) CD10+ CD19- fraction, but not in the more primitive CD34+ CD10- CD19-. These results indicate that IgH gene rearrangements occur in CD34+ BM cells and that they initiate in immature progenitors expressing the CD10, but not yet the CD19 surface antigen. Finally, the presence of IgH gene rearrangements in CD34+ BM cells provides a useful marker of clonality to evaluate the possible involvement of these cells in various B-cell lymphoid malignancies.

Adult↗
PubMed1997

Adjuvant chemotherapy for the treatment of intracranial ependymoma of childhood.

BACKGROUND: Current treatment for childhood intracranial ependymomas with surgery and radiation therapy (RT) yields 5-year survival rates ranging from 50-70% after complete resection to 0-30% after incomplete surgical resection. The role of chemotherapy in the treatment of ependymoma has not been established. In this pilot study, children with newly diagnosed intracranial ependymoma were treated with RT and chemotherapy using agents comparable to those found to be active in the treatment of intracranial ependymoma in infants. METHODS: Nineteen children age 3-14 years (median, 7.5 years) were treated with postoperative RT and chemotherapy. Chemotherapy was comprised of carboplatin, 560 mg/m2, with vincristine, 1.5 mg/m2, weekly for 3 weeks, alternating at 4-week intervals with ifosfamide, 1.8 g/m2, and etoposide, 100 mg/m2, for 5 consecutive days for a total of 4 cycles. RESULTS: The 5-year progression free survival (PFS) estimate was 74%. The extent of surgical resection was not a significant prognostic factor in this study. By contrast, ependymomas located in the posterior fossa were associated with a higher rate of progression (P = 0.036). Toxicity, limited predominantly to myelosuppression, was manageable. CONCLUSIONS: The PFS for children with postoperative residual ependymoma treated with RT and chemotherapy in this study was higher than published survival results for RT alone. These results suggest a role for multialkylator chemotherapy in incompletely resected intracranial ependymoma and provide the rationale for a randomized trial comparing this strategy with conventional postoperative RT.

Adolescent↗
PubMed1997

Phase II study of daily oral etoposide in children with recurrent brain tumors and other solid tumors.

Pre-clinical data and adult experience suggests that topoisomerase targeted anti-cancer agents may be highly schedule dependent, and efficacy may improve with prolonged exposure. To investigate this hypothesis, 28 children with recurrent brain and solid tumors were enrolled in a phase II study of oral etoposide (ETP). Patients were prescribed ETP at 50 mg/m2/ day for 21 consecutive days. Courses were repeated every 28 days pending bone marrow recovery. Evaluation of response was initially performed after 8 weeks and then every 12 weeks either by CT or MRI. Three of 4 patients with PNET (primitive neuroectodermal tumor)/medulloblastora achieved a partial response (PR). Two of 5 with ependymoma responded, one with a complete response and one with a PR. Toxicity was manageable with only 1 admission for fever and neutropenia in 120 cycles of therapy. Five patients had grade 3 or 4 neutropenia. One had grade 4 thrombocytopenia and one grade 2 mucositis and withdrew as a result. One patient had grade 2 diarrhea. Two patients who achieved a PR had received ETP as part of prior combination chemotherapy regimens. Daily oral etoposide is active in recurrent PNET/medulloblastoma and ependymoma. Toxicity is manageable and rarely requires intervention. Daily oral etoposide in combination with crosslinking agents should be considered in future phase III trials. Determination of activity in glioma and solid tumors is not complete.

Administration, Oral↗
PubMed1997

Oxygen transport with oscillations of inspired oxygen concentration.

A theoretical model predicts that forced inspiratory oxygen concentration oscillations can be used to recover cardiorespiratory data and elicit information about the oxygen transport system (Hahn, 1996). The effects of hypoxia on the penetration of these generated oxygen oscillations into arterial and venous blood were explored in dogs exposed to a graded severity of hypoxia. Continuously recorded sinusoidal oxygen oscillations in the respired partial pressure, blood tension and mixed-venous saturation show that the transmission of forced oxygen oscillations from the lungs to the arterial blood depends on the mean arterial saturation. When mean inspired oxygen is high enough to fully saturate arterial haemoglobin, an inspired oscillation can only be transmitted in the blood as an oscillation in oxygen tension. However, in the presence of arterial hypoxaemia, oscillations in both the oxygen saturation and partial pressure of arterial blood are observed. Under these conditions, the oxygen saturation and partial pressure oscillations are also transmitted to mixed-venous blood. Our data illustrates that the link between the arterial and mixed-venous oscillations is non-linear and dependent on the sigmoidal binding relationship between oxygen and haemoglobin.

Animals↗
PubMed1997

Allogeneic bone marrow transplantation for agnogenic myeloid metaplasia. French Society of Bone Marrow Transplantation.

Agnogenic myeloid metaplasia is a rare indication for allogeneic bone marrow transplantation (BMT). We have retrospectively studied 12 patients allografted for this disease within the French BMT group. Prior to BMT, the mean age was 40 years (range 14-49). Diagnosis was based on the Polycythaemia Vera Study Group criteria. Before BMT, 10 patients had been splenectomized, eight required transfusions, and four had received at least two lines of chemotherapy. Cyclophosphamide and total body irradiation was the main conditioning regimen used (n=8). The donor was an HLA-identical sibling except in one case where there was one HLA-DR mismatch. Acute graft-versus-host disease (GVHD) prophylaxis consisted of methotrexate and cyclosporine A. 11 patients engrafted with median times to achieve absolute neutrophil count > 0.5 x 10(9)/l and platelet count > 50 x 10(9)/l of 17 (range 12-44) and 29 (range 12-196) days respectively. One primary graft failure occurred. 10 patients developed grade II-IV acute GVHD, four developed extensive chronic GVHD. One patient relapsed 16 months post-BMT and was untreated and well 14 months later. Three patients died from the BMT procedure. In May 1996 the median follow-up was 25 months and the 4-year overall and event-free survivals were 71% and 59%, respectively. Thus, we conclude that extensive myelofibrosis is not associated with delayed engraftment, and that HLA-identical sibling allogeneic BMT can be considered in a small proportion of patients with agnogenic myeloid metaplasia.

Adolescent↗
PubMed1997

Endocrine outcome in long-term survivors of low-grade hypothalamic/chiasmatic glioma.

OBJECTIVE: We have evaluated the frequency of endocrine abnormalities in a large group of patients with hypothalamic/chiasmatic glioma (H/CG) and its correlation with the different forms of therapy. DESIGN: Descriptive retrospective study using case note review analysis. PATIENTS: The records of 68 children who survived H/CG were analysed. One third had neurofibromatosis. The mean age at tumour presentation was 5 years. The median time of follow-up was 3.6 years. Thirty-eight children received cranial radiation, of whom 17 also had surgery. Surgery was performed in a total of 24 patients. Fifteen patients received only chemotherapy. Eight children, all with neurofibromatosis, received no specific tumour treatment. MEASUREMENTS: Endocrine dysfunction was determined by clinical manifestations and biochemical evaluation of hypothalamic-pituitary function. RESULTS: Endocrine dysfunction occurred in 42% of the children. The most common disorder was GH deficiency (GHD). Of 50 children evaluated, 15 of the 19 with GHD received cranial irradiation (P < 0.05). HOwever, 15 children treated with more than 15 Gy grew normally. Precocious puberty was diagnosed in 11 patients. Nine patients, all treated with cranial irradiation, developed hypogonadotrophic hypogonadism. Of the 14 patients with hypothyroidism, 10 had surgery (P < 0.005). Hypoadrenalism and diabetes insipidus each occurred in eight patients, and were associated with multiple endocrine deficiencies and surgery. Endocrine deficiencies occurred in children with neurofibromatosis as frequently as children without neurofibromatosis but only when comparing those treated with cranial irradiation or surgery. CONCLUSIONS: Nearly all studies assessing the patients with different tumour therapy evaluate patients wit different tumour types. This study investigates a specific and large population of patients with H/CG and correlates the different form of treatment with the endocrine outcome. Precocious puberty, in children with this tumour, is probably due to tumour location rather than oncological therapy. Conversely, although endocrine deficiencies can be a result of tumour location, the major causes of endocrine abnormalities were field irradiation and tumour surgery. A notable finding not previously reported is that endocrine dysfunction occurs less often in neurofibromatosis patients treated conservatively. Furthermore, this study documents that a significant number of young children grew normally despite receiving brain irradiation of greater than 45 Gy.

Adolescent↗
PubMed1997

Sequential versus simultaneous combination antiretroviral regimens for the treatment of human immunodeficiency virus type 1 infection in vitro.

Two-, three-, and four-drug antiretroviral combinations in either simultaneous or sequential regimens were evaluated for their ability to suppress human immunodeficiency virus (HIV) type 1 replication in vitro. Zidovudine, lamivudine, saquinavir, and nevirapine were used at IC(90)s, IC(99)s, or IC(> or = 99)s in a CD4-positive human lymphoblastoid cell line (H9 cells) acutely infected with HIV-1. In sequential regimens, drugs were added at weekly intervals. In simultaneous regimens, all drugs were added on day 0. Increasing the number of drugs in a combination regimen both increased the degree of viral inhibition and delayed the time of breakthrough viral replication. Simultaneous regimens provided more profound and earlier viral inhibition than did sequential regimens. However, sequential addition provided relatively more durable viral inhibition than did simultaneous regimens when drug concentrations were low. The relative effectiveness of different HIV-1 therapeutic strategies depends on both the numbers and concentrations of the drugs used.

Anti-HIV Agents↗