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Biomedical subjects

J Lambert

Publications and source records attributed to J Lambert.

At least 127 records · Page 7Linked to original sources
PubMed1998

Incomplete muscle activation after training with electromyostimulation.

Training with voluntary or electromyostimulation (EMS)-evoked eccentric contractions should produce complete muscle activation, since EMS and eccentric contractions preferentially recruit large motor units. Subjects (22 women ages 18-40) were randomly assigned to a voluntary (VOL; n = 8), EMS (n = 8), or control group. VOL and EMS groups trained the quadriceps at the same, increasing force levels 4 times/week for 6 weeks using voluntary or EMS-evoked eccentric contractions. VOL improved voluntary more than EMS-evoked eccentric strength. EMS improved EMS-evoked strength more than voluntary. EMS training improved EMS-evoked eccentric strength more than VOL training improved voluntary eccentric strength. EMS-evoked to voluntary force ratio increased from 0.57 (+/- 0.11) to 1.20 (+/- 0.35) in EMS and did not change in VOL (all changes p < .05). Six of eight EMS subjects produced greater EMS-evoked force posttraining, suggesting incomplete muscle activation after EMS training.

Adolescent↗
PubMed1998

Normal forces and myofibrillar disruption after repeated eccentric exercise.

To investigate the "rapid-adaptation" phenomenon, we examined force, neural, and morphological adaptations in 12 subjects who performed 100 eccentric contractions with the quadriceps muscle (bout 1) and repeated the same exercise after a 2-wk hiatus (bout 2). Two days after bout 1, quadriceps muscle strength and surface electromyographic (EMG) activity declined approximately 37 and 28%, respectively, in the control group (n = 6). At day 2 after bout 1, significant increases occurred in patellar tendon reflex amplitude (approximately 25%), muscle soreness (fivefold), and serum creatine kinase (220%), and 65 +/- 12% of the total number of pixels in the EMG indicated myofibrillar disruption. At day 7 after bout 1, all variables returned to normal. At day 2 after bout 2, no significant changes occurred in force, EMG, creatine kinase, or soreness, but reflex amplitude increased, and 23 +/- 4% of the total number of pixels in the EMG still indicated myofibrillar disruption. The results suggest that the rapid force recovery following eccentric exercise is mediated at least in part by neural factors and that this recovery may occur independently of cell disruption.

Adaptation, Physiological↗
PubMed1998

Toxic epidermal necrolysis associated with treatment for preterm labor.

We report a 29-year-old pregnant woman who developed toxic epidermal necrolysis at 29 weeks of gestation after administration of ritodrine, indomethacin and betamethasone. Toxic epidermal necrolysis is an unreported side effect of this widely used combination of medications. Since toxic epidermal necrolysis is a potentially fatal disease, awareness of a possible association is warranted.

Adult↗
PubMed1998

Differential protection in two transgenic lines of NOD/Lt mice hyperexpressing the autoantigen GAD65 in pancreatic beta-cells.

Although expressed at very low levels in islets of NOD mice, GAD65 is a candidate islet autoantigen. Two transgenic lines of NOD/Lt mice expressing high levels of human GAD65 from a rat insulin promoter were generated. Transgenes were integrated on proximal chromosome 15 of the A line and on the Y chromosome of the Y line. Transgenic A-line mice were obligate hemizygotes, since homozygous expression resulted in developmental lethality. A twofold higher level of hGAD65 transcripts in A-line islets from young donors was associated with higher GAD protein and enzyme activity levels. Y-line males developed diabetes at a similar rate and incidence as standard NOD/Lt males. In contrast, A-line mice of both sexes exhibited a markedly lowered incidence of diabetes. Insulitis, present in both transgenic lines, developed more slowly in A-line mice and correlated with a reduction in the ratio of gamma-interferon to interleukin-10 transcripts. Splenic leukocytes from young A-line donors transferred diabetes into NOD-scid recipients at a retarded rate compared with those from nontransgenic donors. Further, nontransgenic NOD T-cells transferred diabetes more slowly in NOD-scid recipients that were congenic for A-line transgenes as compared with standard NOD-scid recipients. Primed T-cell responses and spontaneous humoral reactivity to GAD65 failed to distinguish transgenic from nontransgenic mice. Quantitative differences in expression level or insertional mutagenesis are possible mechanisms of protection in the A line.

Adoptive Transfer↗
PubMed1998

Carotid artery stiffness is increased in microalbuminuric IDDM patients.

OBJECTIVE: In IDDM, the development of microalbuminuria, which is associated with an elevation in blood pressure within the normal range, is a risk factor for future cardiovascular disease. Vascular stiffness might be one of the factors involved because it increases systolic blood pressure and the workload of the heart. RESEARCH DESIGN AND METHODS: We investigated carotid artery stiffness with a noninvasive ultrasound method in 24 microalbuminuric and 53 normoalbuminuric IDDM patients and in 54 healthy control subjects. RESULTS: The distensibility coefficient, a measure of intrinsic vascular wall elasticity, was decreased in microalbuminuric IDDM (21.6 x 10(-3)/kPa) as compared with normoalbuminuric IDDM (24.8 x 10(-3)/kPa) and control subjects (25.9 x 10(-3)/kPa; P = 0.02). This result was based on a higher blood pressure in microalbuminuric patients. After correction for the difference in blood pressure, the distensibility coefficients were similar in the three groups. In the two diabetic patient groups taken together, age, blood pressure, female sex, diabetes duration, and cigarette smoking were determinants of a decreased distensibility. CONCLUSIONS: Blood pressure is a major determinant of increased arterial stiffness in microalbuminuric IDDM patients. Increased arterial stiffness may contribute to the accelerated progression of complications if concomitant hypertension exists.

Adolescent↗
PubMed1998

Ambulatory blood pressures and autonomic nervous function in normoalbuminuric type I diabetic patients.

BACKGROUND: In insulin-dependent diabetes mellitus (IDDM) patients with normal urinary albumin excretion (UAE) controversy exists about the presence of blood pressure (BP) elevation and an attenuation of BP decline during sleep. SUBJECTS AND METHODS: These issues were studied in 60 IDDM patients and 55 healthy control subjects with 24 h ambulatory blood pressure monitoring. In addition, in the IDDM patients two cardiovascular reflex tests were performed to study autonomic nervous function. RESULTS: 55 IDDM patients had 4.4/3.1 mm Hg higher 24 h systolic/diastolic pressures when compared with 55 healthy matched controls (P = 0.005/0.009). The diastolic BP decline during sleep was significantly attenuated in IDDM patients compared to healthy volunteers (18.9 vs 22.2%, P = 0.01). The maximum/minimum (max/min) ratio of the RR' interval of the lying to standing test (lower values indicating (incipient) parasympathetic dysfunction) was positively related to the decline of the diastolic BP during sleep in the diabetic patients. This relationship did not persist after adjusting for decline of heart rate during sleep. CONCLUSIONS: IDDM patients with normal UAE, compared with healthy control subjects, have higher BPs during both the waking and sleeping periods and a decreased diastolic BP decline during sleep. In these patients both the diastolic BP decline and the heart rate decline during sleep were related to the max/min ratio. These findings are consistent with the hypothesis that attenuation of diastolic BP decline during sleep is at least partly due to (incipient) damage to the parasympathetic nervous system, which, through a blunted heart rate decline, leads to a decreased decline of cardiac output during sleep.

Adult↗
PubMed1998

[Ataxic hemiparesis with cerebellar dysarthria due to an opercular lesion].

A 63 year-old-man, with an opercular infarct had a motor deficit with ataxic hemiparesis and cerebellar dysarthria. The motor deficit disappeared, but the cerebellar signs remained after three months. A voice instrumental analysis confirmed the cerebellar pattern of the dysarthria. CT and MRI showed the opercular lesion and the normality of the cerebellum and the pons. A volumic MRI analysis precised the localisation and the volume of the lesion. The oxygen consumption (CMRO2) was measured with PET and showed no cerebellar diaschisis. We propose that, in this case, the cerebellar dysarthria is the orofacial ataxic component of the hemiparesis. We suggest that it is related to disruption of the cortico-cerebellar tract, connecting the right orofacial frontal area of the primary motor cortex with the paravermal segment of the left cerebellar hemisphere.

Ataxia↗
PubMed1997

Probucol and multivitamins in the prevention of restenosis after coronary angioplasty. Multivitamins and Probucol Study Group.

BACKGROUND: Oxidizing metabolites generated at the site of coronary angioplasty can induce chain reactions that may lead to restenosis. Antioxidants may counter oxidative stress and modify neointimal formation and vascular remodeling. Experimental data and small clinical studies have suggested that antioxidants may prevent restenosis after angioplasty. In a double-blind, randomized trial, we studied whether drugs with antioxidant properties decrease the incidence and severity of restenosis after angioplasty. METHODS: One month before angioplasty, 317 patients were randomly assigned to receive one of four treatments: placebo, probucol (500 mg), multivitamins (30,000 IU of beta carotene, 500 mg of vitamin C, and 700 IU of vitamin E), or both probucol and multivitamins-all given twice daily. Patients were treated for four weeks before and six months after angioplasty. Patients received an extra 1000 mg of probucol, 2000 IU of vitamin E, both probucol and vitamin E, or placebo 12 hours before angioplasty, according to their treatment assignments. Base-line and follow-up angiograms were interpreted by blinded investigators using a quantitative approach. RESULTS: The mean (+/-SD) reduction in luminal diameter six months after angioplasty was 0.12 +/- 0.41 mm in the probucol group, 0.22 +/- 0.46 mm in the combined-treatment group, 0.33 +/- 0.51 in the multivitamin group, and 0.38 +/- 0.50 mm in the placebo group (P = 0.006 for those receiving vs. those not receiving probucol, and P = 0.70 for those receiving vs. those not receiving vitamins. Restenosis rates per segment were 20.7 percent in the probucol group, 28.9 percent in the combined-treatment group, 40.3 percent in the multivitamin group, and 38.9 percent in the placebo group (P = 0.003 for probucol vs. no probucol). The rates of repeat angioplasty were 11.2 percent. 16.2 percent, 24.4 percent, and 26.6 percent, respectively (P = 0.009 for probucol vs. no probucol). CONCLUSIONS: The antioxidant probucol is effective in reducing the rate of restenosis after balloon coronary angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed1997

A comparative analysis of weight to height and waist to hip circumference indices as indicators of the presence of cardiovascular disease risk factors. Canadian Heart Health Surveys Research Group.

OBJECTIVE: To determine the mathematic formula for weight, height and waist and hip circumference that is most closely correlated to cardiovascular disease risk factors. DESIGN: Population-based, cross-sectional surveys. SETTING: Five Canadian provinces, between 1990 and 1992. PARTICIPANTS: A probability sample of 16,007 men and women aged 18 to 74 years was selected using health insurance registration files in each province. Anthropometry was performed on 10,054 (63%) of these adults. OUTCOME MEASURES: The power of height in the body mass index (BMI, kg/m2) and of hip circumference in the ratio of waist to hip circumference (WC/HC) was varied from 0 to 3. Simple linear regression analysis for each age-sex group was used to examine the relation of each index to systolic and diastolic blood pressure (SBP and DBP), levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL) and high-density lipoprotein cholesterol (HDL), triglycerides (TRIG) and the ratio of TC to HDL. Values for the coefficient of determination (r2) were used to compare the fits of the models. RESULTS: The r2 values were generally low (< 0.27), but were greatest in the younger age groups (18-24 and 35-54 years) and in women. Waist circumference alone (WC/HC0) showed the best fit with SBP and DBP, whereas WC/HC0.5 was most closely related to HDL, TC/HDL and TRIG. None of the indices was closely associated with TC or LDL. Whatever the power of height used, the weight-height ratios showed weaker associations with the risk factors than the waist-hip ratios. CONCLUSIONS: WC and BMI correlate most closely with blood pressure and plasma lipid and may be the best simple anthropometric indices to include in the routine clinical examination of adults.

Adult↗
PubMed1997

Correlation between cardiovascular disease risk factors and simple anthropometric measures. Canadian Heart Health Surveys Research Group.

OBJECTIVE: To assess simple anthropometric measures as indicators of the concurrent presence of high blood pressure, dyslipidemia and diabetes mellitus in adults. DESIGN: Population-based, cross-sectional surveys. SETTING: Five Canadian provinces between 1990 and 1992. PARTICIPANTS: A probability sample of 16,007 men and women aged 18 to 74 years was selected using health insurance registration files in each province. This study is based on the 9826 adults (61%) for whom anthropometric measurements were obtained. OUTCOME MEASURES: Step-wise multiple logistic regression analysis was used to model the association between demographic, anthropometric and risk variables and the presence of high systolic and diastolic (DBP) blood pressure, elevated levels of total (TC), high-density lipoprotein (HDL) and low-density lipoprotein cholesterol, TC/HDL ratio, triglyceride levels (TRIG) and self-reported diabetes mellitus. RESULTS: Age group and sex are strongly associated with all three conditions. Sedentary lifestyle is significantly associated with high DBP, depressed HDL and elevated TC/HDL and TRIG. Anthropometric measures are moderately associated with all conditions. The measures of body fat (body mass index) as well as abdominal fat distribution (waist circumference and ratio of waist to hip circumference) play an approximately equal role. CONCLUSION: Patients' age, sex, level of physical activity, body fat and abdominal fat distribution can be used as indicators of the probability of high blood pressure, dyslipidemia and diabetes mellitus.

Adult↗
PubMed1997

[The Diagnostic Compass; a new contribution to diagnostics].

The Hospital Council has now issued a Diagnostic Compass besides the Pharmacotherapeutic Compass. Its objective is to contribute to a more rational and effective use of diagnostic examinations. The target group comprises physicians involved in using diagnostic tests. The information supplied is based on results of scientific research and don current habits, standards and guidelines. The book has two different approaches: clinical pictures and diagnostic tests. The two volumes are intended to supplement one another.

Diagnostic Techniques and Procedures↗
PubMed1997

A matrix-assisted laser desorption ionization time-of-flight mass spectrometry approach to identify the origin of the glycan heterogeneity of diptericin, an O-glycosylated antibacterial peptide from insects.

In a previous study, electrospray ionization mass spectrometry was used to analyze the structure of the O-glycopeptide diptericin, an antibacterial peptide from the fleshfly Phormia terranovae. Several glycoforms of diptericin differing in the length of their oligosaccharide chains were present at the final stage of purification. In order to determine the origin of this glycan heterogeneity, we analyzed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) the relative abundance of the different diptericin glycoforms in fractions obtained after each purification step, and directly in the hemolymph and in the fat body which produces diptericin. MALDI-MS clearly shows that the purification procedure had no effect on the O-linked oligosaccharide chains of diptericin, suggesting that diptericin is synthesized as a family of heterogeneous glycopeptides. In addition, in these experiments, differential mapping by MALDI-MS of the hemolymph and fat body tissue from bacteria-challenged and naive larvae allowed us to detect induced or repressed molecules which may be involved in the immune response of P. terranovae.

Amino Acid Sequence↗
PubMed1997

An intracellular calcium signal activates p70 but not p90 ribosomal S6 kinase in liver epithelial cells.

In the rat liver epithelial cell lines GN4 and WB, angiotensin II (Ang II) activates the Gq class of regulatory G-proteins, increasing intracellular calcium, protein kinase C activity, and protein tyrosine phosphorylation. We compared the ability of Ang II and other compounds that increase intracellular calcium (i.e. the calcium ionophore A23187 and thapsigargin) or protein kinase C activity (the phorbol ester 12-O-tetradecanoylphorbol-13-acetate) to activate p70 ribosomal S6 kinase (p70(S6K)) and p90 ribosomal S6 kinase (p90(RSK)). In GN4 cells, increasing intracellular calcium stimulated p70(S6K) activity in a rapamycin- and wortmannin- sensitive manner, but did not affect p90(RSK) activity. In contrast, 12-O-tetradecanoylphorbol-13-acetate strongly activated p90(RSK) but only weakly stimulated p70(S6K). The ability of calcium to activate p70(S6K) was confirmed by blocking the A23187-dependent activation through chelation of extracellular calcium with EGTA; the effect of thapsigargin was inhibited by the cell permeant chelator bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethyl ester (BAPTA-AM). Similarly, BAPTA-AM prevented the activation of p70(S6K) by Ang II, suggesting that this signal was largely calcium-dependent. In contrast, the Ang II-dependent activation of mitogen-activated protein kinase and p90(RSK) was not inhibited but was enhanced by BAPTA-AM. These results show that in GN4 cells, Ang II selectively activates p70(S6K) through effects on calcium, p90(RSK) through effects on protein kinase C. The activation of p70(S6K) by calcium stimuli or Ang II was independent of calmodulin but correlated well with the activation of the recently identified, nonreceptor calcium-dependent tyrosine kinase (CADTK)/PYK-2. Both calcium- and Ang II-dependent activation of p70(S6K) were attenuated by the tyrosine kinase inhibitor genistein, and activation of p70(S6K) was higher in GN4 than WB cells, correlating with the increased expression and activation of CADTK/PYK-2 in GN4 cells. In summary, these results demonstrate that intracellular calcium selectively activates p70(S6K) in GN4 cells, consistent with increased CADTK/PYK-2 signaling in these cells.

Amino Acid Sequence↗
PubMed1997

Endothelial dysfunction and pathogenesis of diabetic angiopathy.

OBJECTIVE AND METHODS: To review, from the clinical perspective, the contribution of dysfunction of the vascular endothelium to the pathogenesis of diabetic micro- and macroangiopathy. RESULTS: Available data indicate that endothelial dysfunction in diabetes complicated by micro- or macroalbuminuria (renal microangiopathy) is generalised. The close linkage between microalbuminuria and endothelial dysfunction is an attractive explanation for the fact that microalbuminuria is a risk marker for atherosclerotic cardiovascular disease in diabetes. Endothelial dysfunction precedes the occurrence of even early diabetic microangiopathy. However, it is not clear whether endothelial dysfunction is a feature of the diabetic state per se or whether additional factors are required to induce endothelial dysfunction given the presence of diabetes. Convincing data from animal and in vitro models exist to indicate that endothelial dysfunction in diabetes may be related to hyperglycaemic pseudohypoxia, activation of protein kinase C, increased expression of transforming growth factor-beta and vascular endothelial growth factor, non-enzymatic glycation, oxidative stress, activation of the coagulation cascade, increased expression of tumour necrosis factor-alpha, and high levels of insulin and insulin precursor molecules. However, the importance of these proposed mechanisms have not yet been extensively assessed in diabetes in man. CONCLUSIONS: Endothelial dysfunction plays a key role in the pathogenesis of diabetic angiopathy in man. The biochemical basis of endothelial dysfunction in diabetic man, however, has yet to be fully elucidated.

Albuminuria↗
PubMed1997

The structural components of music perception. A functional anatomical study.

This work explores the cerebral structures involved in the appreciation of music. We studied six young healthy subjects (right handed, French, without musical talent), using a high resolution PET device (CTI 953B) and 15O-labelled water. In three tasks, we studied the effects of selective attention to pitch, timbre and rhythm; a final task studied semantic familiarity with tunes (considered as divided attention for pitch and rhythm). These four tasks were performed on the same material (a tape consisting of 30 randomly arranged sequences of notes). We selected a paradigm, without a reference task, to compare the activations produced by attention to different parameters of the same stimulus. We expected that the activations recorded during each task would differ according to the differences in cognitive operations. We found activations preferentially in the left hemisphere for familiarity, pitch tasks and rhythm, and in the right hemisphere for the timbre task. The familiarity task activated the left inferior frontal gyrus, Brodmann area (BA) 47, and superior temporal gyrus (in its anterior part, BA 22). These activations presumably represent lexico-semantic access to melodic representations. In the pitch task, activations were observed in the left cuneus/precuneus (BA 18/19). These results were unexpected and we interpret them as reflecting a visual mental imagery strategy employed to carry out this task. The rhythm task activated left inferior Broca's area (BA 44/6), with extention into the neighbouring insula, suggesting a role for this cerebral region in the processing of sequential sounds.

Adult↗
PubMed1997

Acute human immunodeficiency virus type 1 disease as a mononucleosis-like illness: is the diagnosis too restrictive?

The purpose of this study was to describe the frequency and duration of clinical features at the time of acute human immunodeficiency virus type 1 (HIV-1) disease in 218 patients with documented symptomatic primary HIV-1 infection. The mean duration of acute HIV-1 disease was 25.1 days (median, 20.0 days) and did not differ by gender, age, and risk factor. The frequency and mean duration of clinical features occurring in >50% of patients were as follows: fever, 77.1% and 16.9 days; lethargy, 65.6% and 23.7 days; cutaneous rash, 56.4% and 15 days; myalgia, 54.6% and 17.7 days; and headache, 50.9% and 25.8 days. Only 15.6% of patients presented with a typical mononucleosis-like illness (MLI) defined as fever, pharyngitis or sore throat, and cervical adenopathy, and 10% had no features of an MLI. A meningitis-like syndrome occurred in 20 patients (9.2%). Acute HIV-1 disease is more diverse than previously reported, and the absence of fever or other MLI features does not rule out acute HIV-1 disease.

Acute Disease↗