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Wiktor SZ, Pate EJ, Rosenberg PS, Barnett M, Palmer P, Medeiros D, Maloney EM, Blattner WA. Mother-to-child transmission of human T-cell lymphotropic virus type I associated with prolonged breast-feeding. JOURNAL OF HUMAN VIROLOGY 1997; 1:37-44. [PMID: 10195229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
OBJECTIVES We assessed the risk of transmitting human T-cell lymphotropic virus type I (HTLV-I) through breast-feeding. STUDY DESIGN/METHODS To assess the risk of mother-to-child transmission of HTLV-I, 212 HTLV-I-seropositive women and 145 HTLV-I-seronegative women were enrolled in a prospective cohort study conducted in Kingston, Jamaica. Their offspring were examined at regular intervals, and HTLV-I serostatus was determined at each visit. RESULTS Twenty-eight of the 181 children with at least one postnatal visit born to HTLV-I-seropositive women (and none of the children born to HTLV-I-seronegative women) were persistently seropositive and were considered HTLV-I infected (Kaplan-Meier estimated cumulative incidence, 18%; 95% CI, 12%-24%). Among children observed for at least 24 months, 19 (32%) of 60 children breast fed for 12 months or longer were HTLV-I seropositive, compared with only 8 (9%) of 86 children breast-fed for less than 12 months (relative risk, 3.4; 95% CI, 1.7-6.9). Compared with children weaned at younger ages, transmission of HTLV-I was associated with continued breast-feeding of children who were 12 to 18 months of age (relative hazard, 6.4; 95% CI, 2.1-180.2) and older than 18 months (relative hazard, 18.1; 95% CI, 1.4-29.5). Transmission was also associated with higher maternal antibody titer (a possible marker of virus load), prolonged duration of ruptured membranes during childbirth, and lower maternal income. CONCLUSIONS These results suggest that limiting the duration of breast-feeding to less than 12 months for children born to HTLV-I-seropositive mothers may significantly reduce mother-to-child transmission of HTLV-I.
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Watson CG, Barnett M, Nikunen L, Schultz C, Randolph-Elgin T, Mendez CM. Lifetime prevalences of nine common psychiatric/personality disorders in female domestic abuse survivors. J Nerv Ment Dis 1997; 185:645-7. [PMID: 9345258 DOI: 10.1097/00005053-199710000-00011] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Cameron-Smith D, Habito R, Barnett M, Collier GR. Dietary guar gum improves insulin sensitivity in streptozotocin-induced diabetic rats. J Nutr 1997; 127:359-64. [PMID: 9039840 DOI: 10.1093/jn/127.2.359] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Although dietary recommendations for diabetics stress the need for increased carbohydrate and dietary fiber, the effectiveness of dietary fiber in improving insulin sensitivity remains controversial. The aim of this study was to compare the effects of a soluble fiber (guar gum) and an insoluble fiber (wheat bran) on insulin sensitivity in streptozotocin-induced (STZ) diabetic rats. Consequently, the rats were divided into two groups and one half were rendered diabetic with streptozotocin. The STZ diabetic and nondiabetic rats were further randomized and fed a diet containing dietary fiber (7 g/100 g diet) from either guar gum or wheat bran. The hyperinsulinemic clamp technique, combined with infusion of the glucose analog, 2-deoxyglucose (2DG), was utilized to examine insulin sensitivity. Bran-fed STZ diabetic rats were significantly (P < 0.001) hyperglycemic, which was ameliorated by guar gum. Insulin-mediated glucose disposal was increased by the guar diet compared with the bran diet in both the STZ diabetic rats [17.7 +/- 2.2 vs. 11.8 +/- 2.4 mL/(kg x min), P < 0.05] and the nondiabetic rats [20.5 +/- 2.8 vs. 15.5 +/- 1.5 mL/(kg x min), P < 0.05]. The accumulation of 2DG in peripheral muscles reflected the changes in insulin sensitivity with a trend for increased 2DG uptake in the majority of analyzed tissues in rats fed the guar diet, both nondiabetic and STZ diabetic, compared with the bran-fed rats. Accompanying these alterations in insulin sensitivity, guar gum suppressed food intake in the hyperphagic diabetic rats by 20% (P < 0.001). The present results demonstrate the effectiveness of guar gum in improving insulin sensitivity in STZ diabetic rats and suggest that reduced food intake may be an important mechanism of action of guar in hyperphagic diabetic rats.
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Sackin P, Barnett M, Eastaugh A, Paxton P. Peer-supported learning. Br J Gen Pract 1997; 47:67-8. [PMID: 9101685 PMCID: PMC1312906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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Barnett M, Habito R, Cameron-Smith D, Yamamoto A, Collier GR. The effect of inhibiting fatty acid oxidation on basal glucose metabolism in Psammomys obesus. Horm Metab Res 1996; 28:165-70. [PMID: 8740190 DOI: 10.1055/s-2007-979153] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We administered etomoxir (an inhibitor of fatty acid oxidation) for five days at a dose of 50 mg/kg/day to three groups of Psammomys obesus. Group A were normoglycemic and normoinsulinemic, group B were normoglycemic and hyperinsulinemic, and group C were hyperglycemic and hyperinsulinemic. When compared with group A, the hyperglycemic/hyperinsulinemic rats of group C had elevated hepatic glucose production (HPG) and elevated glucose uptake (Rg) in all tissues measured reaching statistical significance in white gastrocnemius, soleus and diaphragm. Five days of etomoxir treatment reduced the plasma glucose levels of group C. Etomoxir treatment reduced HGP and although the change was not significant, it was supported by significant reductions of Rg in several tissues including diaphragm, heart, small intestine, brain and white adipose tissue. Five days of etomoxir treatment also reduced the plasma insulin levels in group B and group C, when compared to the levels before treatment. These results demonstrate that inhibition of fatty acid oxidation significantly reduced hyperglycemia, hyperinsulinemia and Rg in some tissues in group C animals suggesting that elevated levels of fatty acid oxidation and increased glucose turnover may be associated with development of NIDDM in Psammomys obesus.
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Clough JE, Foster JA, Barnett M, Wichman HA. Computer simulation of transposable element evolution: random template and strict master models. J Mol Evol 1996; 42:52-8. [PMID: 8576964 DOI: 10.1007/bf00163211] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
It has been proposed that the most extensively studied mammalian retrotransposons replicate by some form of a master template model. This conclusion has been drawn largely from DNA sequence analysis and is based on phylogenetic tree topology, the presence and ordering of shared variants, the degree of divergence between elements within a subfamily, and the shape of the distribution of pairwise differences between elements. To investigate how robust these parameters are as predictors of the model of transposition, computer simulations of the two most extreme transposition models, the Random Template Model and the Strict Master Model, were carried out. A prototype of a computer simulator for studying retrotransposition is presented. The simulator is a versatile digital workbench that maintains DNA sequence data and allows manipulation of a range of factors including reverse transcriptase and in situ mutation rates, transposition template, and transposition rate. All parameters previously used as predictors of the model of transposition were markedly different for the two extreme models when evaluated using large sample sizes of sequences from experiments simulating up to 15 million years of evolution.
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Grigg A, Szer J, Skov K, Barnett M. Multi-organ dysfunction associated with high-dose carboplatin therapy prior to autologous transplantation. Bone Marrow Transplant 1996; 17:67-74. [PMID: 8673058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The specific contribution of high-dose carboplatin to regimen-related toxicity after autologous transplantation has been difficult to determine, particularly in patients receiving cyclophosphamide or ifosfamide. We report five cases of severe multi-system failure in patients receiving high-dose carboplatin in addition to other cytotoxics prior to autologous transplantation. Two of these patients did not receive ifosfamide or cyclophosphamide as part of their chemotherapy. The clinical picture consisted of early onset acute renal failure, arrhythmias and/or myocardial hypokinesia, mental obtundation and other neurological deficits and, in two patients, an acute myopathy. In the two patients in whom serum platinum was measured, levels were very high at the time of marrow infusion. All patients had received prior cisplatin therapy but showed either normal or only modestly impaired creatinine clearance before the transplant. These observations are consistent with a specific clinical syndrome associated with carboplatin toxicity and suggest that creatinine clearance may be inadequate as an indicator of potential renal failure when high-dose carboplatin is used.
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Johnston CM, Barnett M, Sharpe PT. The molecular biology of temperature-dependent sex determination. Philos Trans R Soc Lond B Biol Sci 1995; 350:297-303; discussion 303-4. [PMID: 8570695 DOI: 10.1098/rstb.1995.0165] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Many reptiles do not have heteromorphic sex chromosomes and for these species sex is determined during embryogenesis by the temperature of egg incubation rather than at conception. The phenomenon of temperature-dependent sex determination (TSD) was discovered almost thirty years ago, but few advances have been made towards the elucidation of its mechanism. In the past few years substantial progress has been made in the understanding of the molecular basis of XY chromosomal (genetic) sex determination (GSD) through the discovery of SRY. It is now possible to start comparing TSD with GSD. TSD is found in some evolutionarily ancient vertebrates and has been postulated to be the ancestral process from which GSD has evolved. If this is true then the two mechanisms may share a common molecular basis. This paper details the current knowledge of TSD, our progress on the investigation of the involvement of SRY-type proteins, and finally presents some of the problems that need to be resolved to gain an understanding of the molecular basis of TSD.
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Habito RC, Barnett M, Yamamoto A, Cameron-Smith D, O'Dea K, Zimmet P, Collier GR. Basal glucose turnover in Psammomys obesus. An animal model of type 2 (non-insulin-dependent) diabetes mellitus. Acta Diabetol 1995; 32:187-92. [PMID: 8590789 DOI: 10.1007/bf00838490] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The aim of this study was to examine whole-body glucose turnover and glucose uptake into individual tissues in Psammomys obesus. The animals were classified according to the level of circulating glucose and insulin in the fed state: group A was normoglycaemic and normoinsulinaemic (glucose < 8.0 mmol/l), insulin < 150 mU/l), group B was normoglycaemic and hyperinsulinaemic (glucose < 8.0 mmol/l, insulin > or = 150 mU/l), and group C was hyperglycaemic and hyperinsulinaemic (glucose > or = 8.0 mmol/l, insulin 150 mU/l). The animals were deprived of food for 6 h, after which they were anaesthetized and cannulated, using the jugular vein for infusions and the carotid artery for blood sampling. Whole-body glucose turnover was measured using a primed-continuous infusion of 6-[3H]-glucose and saline to quantitatively assess hepatic glucose production (HGP), glucose disposal (Rd), and the metabolic clearance rate of glucose (MCR). Following the 2-h infusion period, the glucose metabolic index (Rg') of individual tissues was measured using a fixed-dose bolus of 2-deoxy-[14C] glucose. Under the steady-state conditions of the experiment, HGP was assumed to be equal to Rd, and both variables were found to be significantly correlated to the fasting glucose concentration (r=0.534, P<0.05, n=19). On the other hand, MCR was found to be inversely correlated to the fasting plasma glucose concentration (r=0.670 P < 0.01, n=19). When the animals were divided into three groups as described above, HGP in group C animals was significantly elevated compared with group A (20.8 +/- 2.6 vs 12.7 +/- 0.6 mg.kg-1.min-1; P < 0.05), and MCR showed a tendency to be lower in group C than group A, although the difference was not statistically significant. HGP and MCR were not significantly different between groups A and B. Measurement of the glucose metabolic index in individual tissues showed that group C animals had significantly higher Rg' values in muscles and adipose tissues compared with those in group A (P < 0.05). In addition, Rg' in group B white gastrocnemius and soleus were significantly higher than in group A despite similar rates of HGP and levels of glycaemia. These findings suggest that an early increase in skeletal muscle glucose uptake and hyperinsulinaemia can be demonstrated in group B Psammomysobesus before significant hyperglycaemia.
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Yasunaga C, Cramer DV, Tuso PJ, Fujioka H, Barnett M, Yanaga K, Sugimachi K, Makowka L. Endothelial cell antigens associated with accelerated cardiac graft rejection in the rat. Transplant Proc 1995; 27:495-6. [PMID: 7879075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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61
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Barnett M. Medicine: business or profession? Plast Reconstr Surg 1994; 94:1094. [PMID: 7972471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Barnett M, Collier GR, Zimmet P, O'Dea K. The effect of restricting energy intake on diabetes in Psammomys obesus. INTERNATIONAL JOURNAL OF OBESITY AND RELATED METABOLIC DISORDERS : JOURNAL OF THE INTERNATIONAL ASSOCIATION FOR THE STUDY OF OBESITY 1994; 18:789-94. [PMID: 7894516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The aim of this paper was to determine whether restricting energy intake would reduce the elevated levels of glucose, insulin, cholesterol and triglyceride in diabetic Psammomys obesus (sand rat). Between 11 and 12 weeks of age Psammomys obesus were divided into three groups based on blood glucose and plasma insulin levels in the fed ad libitum state; group 1 was normoglycemic (4.4 +/- 0.3 mM) and normoinsulinemic (0.46 +/- 0.04 ng/ml), group 2 was normoglycemic (5.0 +/- 0.3 mM) and hyperinsulinemic (3.58 +/- 0.62 ng/ml) and group 3 was hyperglycemic (11.2 +/- 1.2 mM) and hyperinsulinemic (6.23 +/- 0.73 ng/ml). Energy intake was restricted to 67% of normal for 2 weeks before ad libitum feeding was resumed for a further 2 weeks. Animals in group 3 developed the most abnormalities when compared to group 1 including increased levels of food intake (16.3 +/- 0.5 vs 14.2 +/- 0.5 g/day, P < 0.05), body weight (192 +/- 5 vs 162 +/- 4 g, P < 0.05), triglycerides (1.5 +/- 0.2 vs 0.96 +/- 0.08 mM, P < 0.05), and cholesterol (2.8 +/- 0.2 vs 2.1 +/- 0.1 mM, P < 0.05). In group 3, food restriction was effective in reducing glucose levels (but not insulin) both during and following the restriction period respectively (11.2 +/- 1.2 vs 4.6 +/- 0.5, and 5.9 +/- 1.3, mM, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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Barnett M, Collier GR, Collier FM, Zimmet P, O'Dea K. A cross-sectional and short-term longitudinal characterisation of NIDDM in Psammomys obesus. Diabetologia 1994; 37:671-6. [PMID: 7958537 DOI: 10.1007/bf00417690] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The present study was undertaken to examine the cross-sectional and short-term longitudinal changes in glucose and insulin concentrations as well as measure the enzymatic activity of PEPCK and glycogen synthase in our Psammomys obesus colony. In the cross-sectional study, blood samples were taken from one group of animals at 19 weeks of age (n = 37) in the fed state and following a 4-h fast. In a separate group of 19-week-old animals (n = 69), samples were taken 1 h following an OGTT (1 g/kg body weight) in Psammomys subjected to a 16-h fast. In the longitudinal study, blood samples were taken from one group of animals in the fed state at 7, 11, 15 and 19 weeks of age. All of the cross-sectional data have described the classic inverted U-shaped curve (Starling's curve of the pancreas) in the relationship between glucose and insulin levels. This trend was also reflected by Psammomys subjected to the OGTT; a mild impairment in glucose tolerance was associated with an increase in the insulin response and a further impairment in glucose tolerance was associated with a reduction in the insulin response. Similar results were obtained following a 4-h fast. The short-term longitudinal glucose and insulin data revealed that of the 37 animals examined over the 12-week period, 16 progressed along the inverted U-shaped curve described by the cross-sectional data. Of the other animals, 8 remained unchanged, 7 were unclassifiable and 6 hyperglycaemic Psammomys developed normoglycaemia at the expense of elevated insulin levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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McGlave PB, De Fabritiis P, Deisseroth A, Goldman J, Barnett M, Reiffers J, Simonsson B, Carella A, Aeppli D. Autologous transplants for chronic myelogenous leukaemia: results from eight transplant groups. Lancet 1994; 343:1486-8. [PMID: 7911185 DOI: 10.1016/s0140-6736(94)92589-5] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Chronic myelogenous leukaemia (CML) can be cured by donor marrow transplant. Unfortunately, suitably HLA-matched related or unrelated donors are not available for the majority of patients. Transplant of stem cells derived from a patient's own marrow or peripheral blood (autologous transplant) avoids the need for an HLA-matched donor, is associated with a less complicated and shorter hospital course than donor transplantation, and has been successful in the treatment of other haematological malignancies. We report results of autologous transplants in 200 patients with CML at eight marrow transplant centres over seven years. This is the first multicentre analysis of autologous transplants for CML and reports on the largest number of patients studied to date. We show that autologous transplants provide a plateau in the survival curve not observed in conventional treatments. Autologous transplants are associated with a high engraftment rate, low mortality, and prompt return of both younger and older patients to normal activity levels. Our results suggest that autologous transplants provide an alternative to conventional treatment in the care of patients not eligible for donor transplant.
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Yasunaga C, Cramer DV, Chapman FA, Wang HK, Barnett M, Wu GD, Makowka L. The prevention of accelerated cardiac allograft rejection in sensitized recipients after treatment with brequinar sodium. Transplantation 1993; 56:898-904. [PMID: 8212214 DOI: 10.1097/00007890-199310000-00024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Brequinar sodium (BQR) is a novel immunosuppressive agent that is highly effective in preventing B lymphocyte-mediated antibody production. We have examined the effects of BQR treatment in sensitized recipients on graft survival, donor-specific antibody responses (IgM and IgG), and the appearance of immunopathological lesions present in the grafts. LEW rat recipients were sensitized with single ACI skin graft on day 7 and received heterotopic ACI cardiac grafts on day 0. The recipients rejected the cardiac grafts in an accelerated fashion at day 2.5 post-transplantation, compared to day 7.0 in unsensitized recipients. The animals were treated with low (3 mg/kg/day) or high (12 mg/kg/3x weekly) doses of BQR during skin graft sensitization and/or after challenge with ACI heart allografts. All groups treated with BQR showed significant prolongation of graft survival in the sensitized recipients. The best survival was observed following high-dose BQR therapy during both sensitization and effector phases (median survival time = 40.0 days, P << 0.001). Daily treatment with BQR (3 mg/kg/day) prevented IgM (but not IgG) antibody responses. Treatment with higher doses of BQR (12 mg/kg/3x weekly) before and after skin graft sensitization was effective in preventing both IgM and IgG production. In general, BQR treatment resulted in effective suppression of anti-donor antibody responses, stable graft function, and a reduction in the severity of the acute vascular lesions in the graft. The effectiveness of BQR in preventing accelerated graft rejection when used at 12 mg/kg/3x weekly was comparable to that seen with treatment of sensitized animals with CsA at 15 mg/kg/day for 30 days. Daily treatment with cyclophosphamide at 5 or 15 mg/kg/day was ineffective for preventing graft rejection in sensitized recipients. These results indicated that BQR may provide an important addition to treatment protocols designed to prevent transplantation rejection in presensitized patients. BQR has the ability to significantly inhibit host cellular and humoral immune responses to the donor graft and this facet of the immunosuppressive activity of the drug may be responsible for preventing this aggressive form of rejection.
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Yasunaga C, Cramer DV, Chapman FA, Wang HK, Barnett M, Wu GD, Makowka L. Cardiac graft rejection in hypersensitized recipients: prevention of antibody response and graft rejection using brequinar sodium. Transplant Proc 1993; 25:65-6. [PMID: 8516948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Yasunaga C, Cramer DV, Cosenza CA, Tuso PJ, Chapman FA, Barnett M, Wu GD, Putnam BA, Makowka L. Effect of brequinar sodium on in vivo antibody production. Transplant Proc 1993; 25:40-4. [PMID: 8516942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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69
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Ramsay D, Barnett M, Hüttner W. Identification of triplet levels by Zeeman studies of microwave-optical double resonance in the à 1A2-X̃ 1A1 system of thioformaldehyde. Chem Phys Lett 1993. [DOI: 10.1016/0009-2614(93)90061-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Eaves C, Udomsakdi C, Cashman J, Barnett M, Eaves A. The biology of normal and neoplastic stem cells in CML. Leuk Lymphoma 1993; 11 Suppl 1:245-53. [PMID: 8251904 DOI: 10.3109/10428199309047894] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Chronic myeloid leukemia (CML) has long served as a prototype malignancy for basic as well as clinical studies aimed at developing curative cancer treatment protocols. Well established features of chronic phase CML are its origin in a pluripotent stem cell, a now well defined molecular genetic basis involving the creation of a BCR-ABL fusion gene and evidence of resultant abnormalities in the mechanisms that normally control primitive hemopoietic cell proliferation. We have recently shown how the long-term marrow culture system can be adapted to quantitate and characterize a very primitive cell type in normal blood and marrow samples, as well as their normal and leukemic counterparts in patients with CML. This system has also been used to dissect mechanisms of normal progenitor regulation and to identify specific anomalies affecting leukemic (CML) progenitors. Our studies show that cells detected by their ability to initiate long-term cultures (LTC) of leukemic cells (i.e., CML LTC-initiating cells or LTC-IC) are differently distributed between marrow and blood by comparison to LTC-IC in normal individuals and, although functionally similar in terms of the number and differentiation types of clonogenic cells they produce, CML LTC-IC exhibit defective self-maintenance. Phenotypically these primitive leukemic cells are heterogeneous; the majority display features of activated/proliferating cells but a significant proportion do not. We have also documented heterogeneity in primitive CML cell responses to two factors that specifically and reversibly arrest the cycling of primitive normal hemopoietic cells; i.e., TGF-beta and MIP-1 alpha, to which CML cells are normally responsive and abnormally unresponsive, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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MESH Headings
- Blood Cells/pathology
- Bone Marrow/pathology
- Cell Differentiation/drug effects
- Cell Division/drug effects
- Chemokine CCL4
- Clone Cells/pathology
- Cytokines/pharmacology
- Fusion Proteins, bcr-abl/genetics
- Fusion Proteins, bcr-abl/physiology
- Hematopoietic Stem Cells/drug effects
- Hematopoietic Stem Cells/pathology
- Humans
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/blood
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Macrophage Inflammatory Proteins
- Monokines/pharmacology
- Neoplastic Stem Cells/drug effects
- Neoplastic Stem Cells/pathology
- Phenotype
- Transforming Growth Factor beta/pharmacology
- Tumor Cells, Cultured/drug effects
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Tuso P, Barnett M, Yasunaga C, Nortman D. Cystinuria and renal transplantation. Nephron Clin Pract 1993; 63:478. [PMID: 8459891 DOI: 10.1159/000187262] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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Barnett M, Collier GR, O'Dea K. The longitudinal effect of inhibiting fatty acid oxidation in diabetic rats fed a high fat diet. Horm Metab Res 1992; 24:360-2. [PMID: 1526621 DOI: 10.1055/s-2007-1003335] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This study was designed to examine the time-course of response to inhibition of fatty acid (FA) oxidation in rats rendered mildly diabetic with streptozotocin and fed a high fat diet (50% of energy derived from fat). Etomoxir, a specific carnitine palmitoyltransferase (CPT-1) inhibitor, was administered subcutaneously (12.5 mg/kg) to inhibit long chain fatty acid oxidation. Diabetic and non-diabetic control rats were maintained on the high fat diet. Following an overnight fast, glucose, free fatty acid (FFA) and triglyceride (TG) concentrations were determined after three days, one week and four weeks of treatment. The effect of Etomoxir treatment in reducing fasting glucose concentrations was not evident until after one week, while fasting FFA and TG concentrations were already reduced after three days treatment. All of these changes were maintained over the four week period (P less than 0.001), resulting in reduced levels of fasting plasma glucose (17.6 +/- 2.4 vs 22.3 +/- 1.9 mmol/l), fasting plasma TG (0.32 +/- 0.07 vs 0.98 +/- 0.14 mmol/l) and fasting serum FFA (1.52 +/- 0.26 vs 3.51 +/- 0.69 mEq/l). In addition, the improvements in glucose and lipid levels were accompanied by restored rates of growth towards that of non-diabetic control rats. These results suggest that the short term inhibition of FA oxidation improves fasting glucose, FFA and TG concentrations in diabetic rats fed a high fat diet.
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Manns A, Wilks RJ, Murphy EL, Haynes G, Figueroa JP, Barnett M, Hanchard B, Blattner WA. A prospective study of transmission by transfusion of HTLV-I and risk factors associated with seroconversion. Int J Cancer 1992; 51:886-91. [PMID: 1639536 DOI: 10.1002/ijc.2910510609] [Citation(s) in RCA: 167] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
To evaluate the risk of transfusion-related transmission of HTLV-I in Jamaica, a prospective study was initiated, prior to availability of a licensed HTLV-I serological screening assay. This information would prove useful in formulating strategies for blood-donor screening. We followed 118 pre-transfusion HTLV-I-negative transfusion recipients at monthly intervals post-transfusion for 1 year. Laboratory and questionnaire data were obtained at each visit to evaluate the clinical and immunological status of recipients. Cumulative incidence of HTLV-I seroconversion was estimated and risk-factor data associated with seroconversion among 66 HTLV-I-exposed transfusion recipients were analyzed. Seroconversion occurred in 24/54 (44%) of recipients of HTLV-I-positive cellular blood components, 0/12 recipients of positive non-cellular donor units and 0/52 recipients of HTLV-I-negative donor units. Significant risk factors associated with recipient seroconversion were receipt of a seropositive cellular blood component stored for less than one week [odds ratio (OR) = 6.34, 95% confidence interval (CI) = 1.83 to 21.92], male sex (OR = 4.79, 95% CI = 1.15 to 20.0) or use of immuno-suppressive therapy at time of transfusion (OR = 12.20, 95% CI = 0.95 to 156). Risk of blood-borne infection per person per year in Jamaica was estimated to be 0.009%. Our results confirm that blood transfusion carries a significant risk of HTLV-I transmission and that screening of donor blood effectively prevents HTLV-I seroconversion. Recipients at greatest risk for seroconversion were those who required multiple transfusions or who were receiving immunosuppressive therapy at the time of transfusion. These patients should be given priority in receiving selectively screened blood components, if universal blood-donor screening for HTLV-I is not possible.
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Abstract
Sprague-Dawley rats were surgically fitted with gastric fistulas and their intakes of 6% ethanol measured first with the fistula closed (normal drinking) and then on three test sessions with the fistula open (sham drinking). The rats were water deprived prior to the 1-h test sessions. On the second and third sham drinking sessions, intakes of alcohol were significantly increased above those in both the closed and first open fistula session. The effectiveness of the sham ingestion preparation to minimize absorption was shown by the much lower blood alcohol levels in sham compared with real drinking rats. Thus, reduction of the postingestive effects of alcohol leads to an acquisition of increased oral consumption. The similarities and differences between sham intakes of water and alcohol are discussed.
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Nelson CW, Snow FR, Barnett M, McRoy L, Wechsler AS, Nixon JV. Impending paradoxical embolism: echocardiographic diagnosis of an intracardiac thrombus crossing a patent foramen ovale. Am Heart J 1991; 122:859-62. [PMID: 1877463 DOI: 10.1016/0002-8703(91)90539-t] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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