Prolonged corrected QT interval is associated with acute and chronic hyperinsulinemia in nondiabetic subjects.
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Acute Disease↗
Biomedical subjects
Leo Niskanen
Publications and source records attributed to Leo Niskanen.
Metabolic syndrome in patients with schizophrenia.
BACKGROUND: Our aim was to study the frequency of metabolic syndrome and associated factors in patients with schizophrenia. METHOD: The study group consisted of 35 outpatients with long-term schizophrenia defined by DSM-IV criteria. Patients were assessed for the presence of metabolic syndrome, which was defined by the criteria of the National Cholesterol Education Program. All patients were on antipsychotic medication. Data were collected from Jan. 1, 2001, to Aug. 30, 2001. RESULTS: Metabolic syndrome was found in 37% (N = 13) of the patients, and it was associated inversely with the total daily dose of, but not with any specific type of, antipsychotic drug. CONCLUSION: The results suggest that metabolic syndrome is common among patients with schizophrenia, and it may be far more common than in general populations.
Adolescent↗
Association between Chlamydia pneumoniae antibodies and intimal calcification in femoral arteries of nondiabetic patients.
BACKGROUND: Chlamydia pneumoniae, a gram-negative bacterium, has been suggested to be a risk factor for atherosclerosis. Calcium is a well-known component of atherosclerotic plaques, but it is uncertain whether infectious agents play a role in the calcification process of the arteries. PATIENTS: To address this issue we investigated the association of Chlamydia antibodies with intimal arterial calcification as assessed by soft tissue radiograms from the thigh region of 1373 nondiabetic Finnish individuals aged 45 to 64 years. RESULTS: At baseline, radiologically detectable intimal calcification in femoral arteries was found in 172 (27%) of 638 men and 43 (6%) of 735 women (P<.001). The presence of intimal artery calcifications was strongly related to conventional atherosclerotic risk factors and to Chlamydia antibodies. In Cox regression analysis, association of Chlamydia antibodies with intimal artery calcification persisted after extensive adjustment for other cardiovascular risk factors (P =.04). A dose-response relationship was observed between Chlamydia antibodies and intimal femoral artery calcification (P =.006). The presence of intimal artery calcification was strongly associated with an increased risk of future coronary heart disease mortality (P<.001). CONCLUSION: Chlamydia antibodies are strongly associated with intimal calcification of the femoral arteries.
Antibodies, Bacterial↗
Hyaluronan expression in differentiated thyroid carcinoma.
The extracellular polysaccharide hyaluronan (HA) controls cell migration, differentiation, and proliferation, and is supposed to contribute to the spreading of several human cancers. Little is known about the role of HA in the development and progression of differentiated thyroid carcinoma (DTC). The expression and prognostic value of HA were therefore evaluated in 204 consecutive patients with DTC. A biotinylated affinity probe specific for HA was applied to paraffin-embedded tumour samples to assay the expression of HA in carcinoma cells and in intra/peritumoural stroma. In a majority of the samples, a high percentage (>or=90%) of normal thyroid follicle epithelial cells were HA-positive. This high percentage was also found in 80 (47%) papillary carcinomas, but only in seven (21%) follicular carcinomas (p=0.004). Age (>60 years) of the patients was significantly associated with a low percentage of HA-positive cancer cells (p=0.013). Cancer cell-associated HA correlated significantly with the percentage of cells expressing total CD44 and its isoforms containing exons v3 and v6 (r=0.223-0.289, p<0.001 for all). The tumour stroma was always positive for HA. Stromal staining intensity did not differ markedly between papillary and follicular carcinomas. A strong stromal HA staining intensity was related to distant metastases (p=0.044), high pTNM stage (p=0.024), old age (>60 years) (p=0.043), and cancer-related mortality (p=0.001). In a log-rank univariate survival analysis, strong stromal HA staining intensity was related to DTC mortality (p=0.0007). Cancer cell-associated HA expression did not significantly correlate with patient survival. In Cox's multivariate survival analysis, age (>60 years, p=0.0164), gender (p=0.0251), and pTNM stage (p=0.0121) were significant independent prognostic factors for DTC-related death. These results suggest that strong stromal HA staining intensity is related to progression and unfavourable outcome in DTC patients, while the clinical factors remain more powerful in predicting DTC-related death.
Adolescent↗
Iris transluminance in type 2 diabetes.
PURPOSE: Cross-sectional analysis of iris transluminance in type 2 diabetic patients compared with control subjects, all followed in a cohort study. METHODS: A cohort consisting of a well-characterized group of 82 type 2 diabetic patients were followed for 10 years after diagnosis, as were 125 control subjects. The prevalence of iris transluminance was determined by transscleral transillumination and by grading of black-and-white positive prints at the 10-year examination. The frequency of diabetic retinopathy was prospectively determined by grading of fundus photographs at baseline and after five and 10 years. RESULTS: Iris transluminance was found in 27% of diabetic patients and 8.0% of control subjects (P = 0.001). The diabetic patients with more severe and short-term retinopathy more commonly had abnormal iris transluminance than those with no or only mild retinopathy (P < 0.05). Iris transluminance was not associated with intraocular pressure or glycemic control. CONCLUSIONS: In type 2 diabetic patients, abnormal iris transluminance tended to associate with more severe and short-term retinopathy. Therefore we assume that hypoxia is responsible for the defects in the pigment layer of the iris. Thus, abnormal iris transluminance may serve as a marker for rapidly progressive retinopathy.
Diabetes Mellitus, Type 2↗
Anthropometry, bioelectrical impedance and dual-energy X-ray absorptiometry in the assessment of body composition in elderly Finnish women.
In this study, the bioelectrical impedance analysis (BIA), skinfold thickness measurement (STM) and dual-energy X-ray absorptiometry (DXA), as a reference method, were compared with each other in the assessment of body composition in elderly (62-72-year-old) Finnish women (n=93). BIA had better agreement with DXA in the assessment of fat free mass (FFM, R2=0.70, Sres=2.1) and fat mass (FM, R2=0.93, Sres=2.3) than the STM (FFM, R2=0.62, Sres=2.4; FM, R2=0.89,Sres=2.8). There was quite a large variation in the estimates when different BIA prediction equations were used. The equation developed in this study, FFM (kg)=-128.06 + 1.85 x BMI-0.63 x weight + 1.07 x height - 0.03 x resistance +10.0 x waist-hip ratio, yielded a small and unbiased error (0.5 +/- 1.6 kg), with a small residual standard deviation (R2=0.83, Sres=1.6). However, error associated with the estimate of FM was positively related to the degree of FM. BIA(Heitmann) equation yielded unbiased estimates of both FFM and FM (FFM, R2=0.77, Sres=1.8; FM, R2=0.95, Sres=1.9). Both the STM and BIA (manufacturer's equation) resulted in error which was statistically significant and positively correlated with FFM and FM. These results indicate that BIA prediction equations, chosen with care, can improve the performance of equations based upon anthropometric measurements alone in the assessment of body composition in elderly women.
Absorptiometry, Photon↗
Gender influence on vasoactive hormones at rest and during a 70 degrees head-up tilt in healthy humans.
To evaluate the influence of age and gender on the neuroendocrine control of blood pressure in normal subjects, a 13-min 70 degrees head-up tilt (HUT) was applied after 3 h of recumbency to 109 healthy men and women aged 23-50 yr (age group I) and 51-77 yr (age group II). We found that age and gender had a significant influence on plasma norepinephrine (PNE) concentration at baseline and in the upright position. PNE was significantly higher in older men compared with the younger men and women of both age groups, suggesting a divergent age-related activation of the sympathetic nervous system between genders at baseline as well as during a sustained orthostatic challenge. There was no significant influence of age or gender on plasma epinephrine at baseline or during HUT. Plasma renin activity was significantly higher at baseline as well as in the upright position during HUT in elderly men than in women. Age or gender had no influence on plasma vasopressin (PAVP), and, regardless of age, nonhypotensive HUT induced an extremely modest increase in PAVP. The syncopal subjects displayed a hormonal pattern associating increased PNE and a surge in plasma epinephrine and PAVP minutes before syncope during HUT. The orthostatic intolerance appears not to be a feature of healthy aging per se. In healthy subjects, both age and gender modulate markedly the cardiovascular and neuroendocrine responses to an orthostatic challenge and must be taken into consideration, particularly when catecholamine responses are studied.
Adult↗
Carriers of an inactivating beta-cell ATP-sensitive K(+) channel mutation have normal glucose tolerance and insulin sensitivity and appropriate insulin secretion.
OBJECTIVE: Insulin release from the pancreatic beta-cells is controlled by ATP-sensitive K(+) (K(ATP)) channels, which consist of a hetero-octameric complex of four sulfonylurea receptor 1 (SUR1) and four Kir6.2 proteins. Mutations in the SUR1 gene are the major cause of congenital hyperinsulinemia (CHI). Despite the hereditary nature of CHI, studies of glucose homeostasis in heterozygous relatives of CHI patients are lacking. Theoretically, in the heterozygous state of the SUR1 gene mutation, only 1 of 16 K(ATP) channels consists of entirely normal subunits. The aim of our study was to investigate in vivo the glucose homeostasis of heterozygous SUR1 mutation carriers. RESEARCH DESIGN AND METHODS: We studied 8 parents of CHI patients, all 8 of whom were heterozygous for the inactivating SUR1 mutation V187D, and 10 matched control subjects. We evaluated glucose tolerance and insulin secretory capacity with oral and intravenous glucose tests, rates of whole-body glucose uptake with hyperinsulinemic-euglycemic clamps, C-peptide response to hypoglycemia during hyperinsulinemic-hypoglycemic clamp, and function of the K(ATP) channels with intravenous tolbutamide test. RESULTS: Carriers of the V187D substitution had normal glucose tolerance, normal tissue sensitivity to insulin, and no signs of inappropriate insulin secretion. The normal insulin response to tolbutamide indicated that heterozygosity for the V187D mutation did not impair K(ATP) channel function. CONCLUSIONS: We conclude that the heterozygous carriers of the SUR1 mutation had normal glucose metabolism and insulin secretion, indicating that carriers of recessive K(ATP) channel mutations are unlikely to be at an increased risk of hypoglycemia or other disturbances in glucose metabolism.
ATP-Binding Cassette Transporters↗
Does postmenopausal hormone replacement therapy affect cardiac autonomic regulation in osteoporotic women?
OBJECTIVE: Postmenopausal hormone replacement therapy (HRT) has been associated with reduced risk of cardiovascular disease; however, the mechanisms remain obscure, and it is not known whether this applies to regimens containing both estrogen and progestin. One possibility is that estrogen would act via enhancement of cardiac autonomic regulation. DESIGN: In this prospective, controlled study of 6-months duration, 22 osteoporotic, postmenopausal women in the intervention group were treated with combined estradiol hemihydrate corresponding to estradiol 2 mg and norethisterone acetate 1 mg with or without clodronate (HRT group). Nine women in the control group received clodronate only. Indices of heart rate variability (HRV) by power spectral analyses and baroreceptor sensitivity (BRS) by phenylephrine test were measured before and after 3 and 6 months of treatment. RESULTS: The total power of HRV remained identical within the groups, although it was higher at 3 and 6-month measurements in the control group than the HRT group. This was mainly due to lower very low frequency and high frequency power in the HRT group. However, no changes in the low frequency/high frequency-ratio of HRV, an index of sympathovagal balance, were observed between and within the groups. Further, during the intervention, no significant changes in BRS (baseline and 6 months: 5.0 +/- 2.1 and 5.1 +/- 2.5 ms/mmHg) within the HRT group was observed. CONCLUSIONS: The impact of estrogen and progesterone on cardiac autonomic regulation seems to be quite modest. Therefore, cardiac morbidity and mortality are probably not mediated by their effects on cardiac autonomic regulation. However, the effects of estrogen alone or more selective estrogen receptor modulators need yet to be clarified in future studies.
Anthropometry↗