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Biomedical subjects

T J Allain

Publications and source records attributed to T J Allain.

10 recordsLinked to original sources
PubMed1997

Changes in growth hormone, insulin, insulinlike growth factors (IGFs), and IGF-binding protein-1 in chronic fatigue syndrome.

Chronic fatigue syndrome (CFS) is characterized by severe physical and mental fatigue of central origin. Similar clinical features may occur in disorders of the hypothalamopituitary axis. The aim of the study was to determine whether patients with CFS have abnormalities of the growth hormone/insulinlike growth factor (GH-IGF) axis basally or following hypothalamic stimulation with insulin-induced hypoglycemia. We compared levels of GH, IGF-I, IGF-II, IGF-binding protein-1 (IGFBP-1), insulin, and C-peptide in nondepressed CFS patients and normal controls. We found attenuated basal levels of IGF-I (214 +/- 17 vs. 263.4 +/- 13.4 micrograms/L, p = .036) and IGF-II (420 +/- 19.8 vs. 536 +/- 24.3 micrograms/L, p = .02) in CFS patients and a reduced GH response to hypoglycemia (peak GH; 41.9 +/- 11.5 vs. 106.0 +/- 25.6 mU/L, p = .017). Insulin levels were higher (7.6 +/- 1.0 vs. 4.3 +/- 0.8 mU/L, p = .02) and IGFBP-1 levels were lower (19.7 +/- 4.6 vs. 43.2 +/- 2.7 mg/L, p = .004) in CFS patients compared with controls. This study provides preliminary data abnormalities of the GH-IGF axis in CFS. It is not apparent whether these changes are components of a primary pathological process or are acquired secondary to behavioral aspects of CFS such as reduced physical activity.

Adult↗
PubMed1996

The isoform-specific expression of the tri-iodothyronine receptor in osteoblasts and osteoclasts.

Hyperthyroidism is associated with an increase in both osteoblast and osteoclast activity. We have previously shown that, in vitro, osteoclasts do not respond directly to tri-iodothyronine to increase bone resorption but that the effect is mediated by another bone cell, probably the osteoblast. To investigate this issue further we have studied the isoform-specific expression of thyroid receptor (TR) protein in human osteoclasts derived from an osteoclastoma (giant cell tumour of bone) and the expression of TR mRNA and protein in the osteoblastic cell lines MG 63 and UMR 106. Three major TR receptor variants have been described; TR alpha 1 and TR beta are functional receptors whereas c-erbA alpha 2 is a non-functional variant. Northern blot analysis using [32P]-cDNA probes against human TR alpha 1, c-erbA alpha 2 and TR beta demonstrated specific binding of these probes to mRNA from MG 63 and UMR 106. mRNA for all three receptor variants was observed in both cell lines, in UMR 106 multiple mRNA transcripts were present for TR alpha 1 and TR beta. Immunohistochemical staining with antibodies recognizing a common TR alpha epitope and specific c-erbA alpha 2 and TR beta epitopes extended these observations by demonstrating receptor protein in both osteoblasts and osteoclasts. These findings are consistent with previous observations of TR expression in osteoblast-like-cells and are the first direct demonstration of TR in osteoclasts.

Animals↗
PubMed1996

Abbreviated Mental Test (AMT) in the elderly: shortcoming of an adapted AMT in Zimbabwe.

OBJECTIVE: To measure the abbreviated mental test (AMT)-and to determine factors which might influence this in a group of Zimbabwean elders. DESIGN: Community based cross sectional survey. SETTING: Randomly selected households within randomly selected villages and two high-density urban areas in north eastern Zimbabwe. SUBJECTS: 278 subjects aged 60 to 92 years (124 male, 154 female). INTERVENTIONS: A questionnaire, including the AMT, was administered, at home, by trained research nurses. MAIN OUTCOME MEASURES: AMT-literacy rates, visual acuity, social and demographic information. RESULTS: 128 (46pc) scored less than seven, a level normally associated with significant mental impairment. Only one subject was actually disoriented in time and place. Multiple regression analysis confirmed that increasing age, female sex, rural evidence, lack of formal education, reduced visual acquity and not currently living with a spouse were all independent factors associated with low AMT score. CONCLUSION: It was apparent that the AMT was not a valid tool for screening for confusion in Zimbabwean elderly, since the prevalence of senile-dementia is increasing in the developing world. It is important to develop a screening test for use in Zimbabwe which is sensitive but is independent of these confounding variables.

Aged↗
PubMed1995

A histomorphometric study of bone changes in thyroid dysfunction in rats.

Clinical studies in thyrotoxicosis reveal a state of high bone turnover leading, eventually, to osteoporosis. Recently there has been concern that thyroxine (T4) treatment may have a similar effect on bone. Rat models have been used to study the effects of T4 on bone, but the majority of studies have looked at the effects of T4 after only 3 weeks of treatment. The aim of this study was to evaluate histomorphometric changes in rats after 12 weeks of thyroxine overtreatment or 12 weeks of hypothyroidism compared with untreated control animals. Animals received either T4 200 micrograms/kg per day, 0.1% propylthiouracil, or vehicle for 12 weeks. Tetracycline was administered 1 week and 3 weeks prior to killing. Iliac crest bone was used for histomorphometry. Serum T4 measurements (taken at killing) confirmed hyper- and hypothyroidism in the appropriate animal groups (between group difference p < 0.001 by ANOVA). In hyperthyroid animals there was an increase in mineral apposition rate (MAR; 0.94 vs. 0.59 microns/day, p < 0.001) and mineral formation rate (MFR/BS; 0.24 vs. 0.12 x 10(-2) micron3/micron2 per day, p < 0.001) and a slight increase in eroded surfaces (ES/BS%; 1.54 vs. 1.36, p < 0.05) compared with controls, consistent with previous in vitro and in vivo observations. In hypothyroid rats there was a marked reduction in osteoid surfaces (OS/BS%; 1.7 vs. 24.8, p < 0.001) and MAR (0.3 vs. 0.59 micrograms/day, p < 0.001), a reduction in ES/BS% (0.51 vs. 1.36, p < 0.05), and an increase in cancellous bone volume (BV/TV%; 30.29 vs. 19.6, p < 0.05), suggesting that thyroid hormones are a requirement for normal bone turnover.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1995

A case of gram negative pericarditis in a patient with the Acquired Immunodeficiency Syndrome.

A diagnosis of pericarditis due to Escherichia coli was made in a 38 year old male patient with AIDS. The source of infection in this patient was not established. This case highlights the need to carry out a diagnostic pericardiocentesis in immunocompromised patients presenting with pericardial effusions and the importance of adequate antibiotic cover when treating such patients prior to microbiological confirmation of the causative organism.

AIDS-Related Opportunistic Infections↗
PubMed1992

Tri-iodothyronine stimulates rat osteoclastic bone resorption by an indirect effect.

Tri-iodothyronine (T3) increases bone resorption in vivo and in vitro. In order to understand further the mechanisms by which this occurs we studied the effects of T3 at concentrations in the range of 1 pmol/l-1 mumol/l on bone resorption by osteoclasts isolated from neonatal rat long bones. Osteoclasts were disaggregated and incubated either with or without UMR 106 cells or with mixed bone cells. We found that there was no effect of T3 on bone resorption by osteoclasts incubated alone or co-cultured with UMR 106 cells. However, in culture with mixed bone cells there was a significant relationship between the concentration of T3 and bone resorption (r = 0.54, P = 0.01). The greatest effect was observed at a T3 concentration of 1 mumol/l at which a 1.8-fold increase in resorption was seen compared with control (P less than 0.005; paired t-test). We conclude that the ability of T3 to increase osteoclastic bone resorption is not due to a direct action of T3 on osteoclasts but is mediated by another cell present in bone. The observation that UMR 106 cells are unable to mediate this effect suggests that either the mediating cell is not osteoblastic or the phenotype of UMR 106 does not conform to the phenotype of osteoblastic cells that mediate the T3 responsiveness of bone.

Animals↗