Genetic refinement and physical mapping of the CMT4B gene on chromosome 11q22

Charcot-Marie-Tooth disease type 4B (CMT4B) is a demyelinating autosomal recessive motor and sensory neuropathy characterized by focally folded myelin sheaths in the peripheral nerve. We recently mapped the CMT4B gene to a 5-cM interval on chromosome 11q22, using homozygosity mapping and haplotype sharing analysis on a large inbred pedigree. In the present study, we report the construction of a YAC-based transcript map across the 5-cM critical region, including 26 YACs, 35 STSs, and 52 ESTs. Furthermore, using 15 additional physically ordered microsatellite markers from the 11q22 region on the original inbred family, we were able to narrow the critical interval for the gene to 2 Mb, which is now flanked by markers D11S1757 and CHLC-GATA3B05. Finally, after computer analysis of the 33 ESTs assigned to the 2-Mb interval, we demonstrated that 21 different transcripts as well as 3 known genes might represent potential candidates for the disease.

Effects of glucose ingestion on cardiac autonomic nervous system in healthy centenarians: differences with aged subjects

BACKGROUND

Spectral analysis of heart rate variability (HRV) investigates the cardiac autonomic nervous system (ANS) activity. In particular, low frequency/high frequency (LF/HF) is considered an index of cardiac sympatho-vagal balance and is stimulated by glucose ingestion in healthy subjects. No studies have evaluated the effect of glucose ingestion on cardiac ANS in centenarians.

MATERIALS AND METHODS

In 30 healthy centenarians (HC) and 25 aged subjects (AS) power spectral analysis of HRV was investigated during an oral glucose ingestion.

RESULTS

Glucose ingestion rose LF/HF ratio in both groups studied. Such stimulatory effects were restrained to the first 60 min of the study. Independent of age, gender, body mass index (BMI) and fasting plasma norepinephrine and FT3 concentrations, HC had basal total power (1318 +/- 546 vs. 1918 +/- 818 msec2, P < 0.01), lower low frequency (LF) (33 +/- 21 vs. 50 +/- 11 n.u., P < 0. 03), and higher high frequency (HF) (74 +/- 18 vs. 43 +/- 15 n.u., P < 0.05) than AS. Consequently, LF/HF ratio (0.43 +/- 0.07 vs. 0.91 +/- 0.05, P < 0.02) was also lower in HC than in AS. In AS, but not in HC, the baseline LF/HF ratio correlated significantly with BMI (r = 0.48, P < 0.01), waist-hip-ratio (WHR) (r = 0.45, P < 0.02), fasting plasma insulin (r = 0.49, P < 0.01) and norepinephrine (r = 0.57, P < 0.02) concentration. Glucose ingestion was associated with a significant rise in LF/HF ratio in both groups studied but per cent changes in glucose mediated stimulation of LF/HF was lower in HC than in AS. In a control study, water administration did not affect power spectral parameters of HRV.

CONCLUSION

Our study demonstrates that basal- and glucose-stimulated LF/HF, an indirect index of cardiac sympatho-vagal balance, are lower in HC than in AS.

Vitamin E deficiency due to chylomicron retention disease in Marinesco-Sjögren syndrome

We report on 2 brothers (aged 19 and 12 years) with Marinesco-Sjögren syndrome who also had very low serum vitamin E concentrations with an absence of postprandial chylomicrons. The molecular study ruled out ataxia with isolated vitamin E deficiency, abetalipoproteinemia, and hypobetalipoproteinemia. The electron microscopy of the intestinal mucosa was consistent with a chylomicron retention disease. We speculate that both chylomicron retention disease and Marinesco-Sjögren syndrome are related to defects in a gene crucial for the assembly or secretion of the chylomicron particles, leading to very low serum levels of vitamin E.

Effects of insulin on the cardiac autonomic nervous system in insulin-resistant states

The effects of insulin infusion on cardiac autonomic nervous system (ANS) activity were investigated in healthy subjects (n=15) and in patients with various types of insulin-resistance, such as obese subjects (n=20) and those with hypertension (n=15) or type II (non-insulin-dependent) diabetes (n=22). Healthy subjects and patients underwent euglycaemic hyperinsulinaemic glucose clamp, and cardiac ANS and haemodynamic changes were investigated by continuous recording of heart rate variability by the Holter technique and by venous occlusion plethysmography respectively. At baseline, healthy subjects had the highest values for total spectral power and the low-frequency (LF) component, and the lowest value for the high-frequency (HF) component. In the pooled data (n=72), the fasting plasma insulin concentration was correlated with baseline total spectral power (r=-0.37; P<0.001) and the LF/HF ratio (r=-0. 35; P<0.003). Such correlations were still significant (P<0.01 for both) after adjustment for body fat and mean arterial blood pressure. In a multivariate linear stepwise analysis (n=72), a model including body fat, waist/hip ratio, fasting plasma glucose concentration and insulin-mediated glucose uptake explained 47% of the variability of the change in the LF/HF ratio, with body fat (t=-3.11; P<0.01) and insulin-mediated glucose uptake (t=-3.48; P<0. 008) being significantly and independently associated with insulin-mediated changes in the LF/HF ratio. Insulin infusion reduced the total spectral power and increased the LF/HF ratio in healthy subjects, but not in insulin-resistant patients. In conclusion, our study demonstrates that insulin fails to stimulate cardiac ANS activity in insulin-resistant patients, independently of the causes of insulin resistance.

Familial temporal lobe epilepsy autosomal dominant inheritance in a large pedigree from southern Italy

To further elucidate the inheritance pattern and range of phenotypic manifestations of benign familial temporal lobe epilepsy (FTLE), we report a large family recently identified in southern Italy. There were 8 patients (4 men), ranging in age from 31 to 68 years in three generations. One affected patient was deceased at the time of the study. Genealogical study strongly supported autosomal dominant inheritance with incomplete penetrance, as three unaffected individuals transmitted the disease. Clinical anticipation could not be assessed because of the ascertainment method. Male to male transmission occurred. Identifiable antecedents for seizures were present in only two patients, who had a simple febrile convulsion and a closed head trauma, respectively. Migraine was overrepresented in this family. Onset of seizures ranged from 17 to 52 years (mean: 27 years). All patients had weekly simple partial seizures suggestive of temporal origin with vegetative or experiential phenomena. Very rare partial complex seizures occurred in 6/7 patients. One had two generalized nocturnal seizures as well. Two had previously been misdiagnosed as having gastritis or panic attacks, and one had not been diagnosed. Interictal anteromesiotemporal spiking was seen in 5/7 patients, and occurred mostly during NREM sleep. Neurological examination, brain CT or MR scans were normal. Antiepileptic medication always controlled the seizures.

Genetic refinement and physical mapping of the CMT4B gene on chromosome 11q22

Charcot-Marie-Tooth disease type 4B (CMT4B) is a demyelinating autosomal recessive motor and sensory neuropathy characterized by focally folded myelin sheaths in the peripheral nerve. We recently mapped the CMT4B gene to a 5-cM interval on chromosome 11q22, using homozygosity mapping and haplotype sharing analysis on a large inbred pedigree. In the present study, we report the construction of a YAC-based transcript map across the 5-cM critical region, including 26 YACs, 35 STSs, and 52 ESTs. Furthermore, using 15 additional physically ordered microsatellite markers from the 11q22 region on the original inbred family, we were able to narrow the critical interval for the gene to 2 Mb, which is now flanked by markers D11S1757 and CHLC-GATA3B05. Finally, after computer analysis of the 33 ESTs assigned to the 2-Mb interval, we demonstrated that 21 different transcripts as well as 3 known genes might represent potential candidates for the disease.

The dopamine D2 receptor gene is a susceptibility locus for Parkinson's disease

The dopamine D2 receptor (DRD2) gene has been proposed as a candidate gene underlying several psychiatric and neurologic disorders. The aim of the present study was to examine if selected polymorphisms in the DRD2 gene are associated with Parkinson's disease (PD). We determined the allelic frequencies for four polymorphisms located in the DRD2 gene in a sample of 135 patients with PD and 202 normal control subjects. No significant difference was observed in the allelic frequencies between patients with PD and control subjects with regard to the -141C Ins/Del and the Ser311/Cys311 variants. On the contrary, the A1 allele of the TaqIA polymorphism and the B1 allele of the TaqIB polymorphism were more frequent in patients with PD than in control subjects (control subjects: TaqIA A1 = 14.6%, TaqIB B1 = 10.6%; patients with PD: TaqIA A1 = 20.7%, TaqIB B1 = 17.4%). Patients carrying the A1 allele or the B allele had an increased risk of developing PD (TaqIA, odds ratio: 1.71, 95% confidence intervals: 1.08-2.73; TaqIB, odds ratio: 1.83, 95% confidence intervals: 1.12-3.02). The TaqIA and TaqIB polymorphisms were in strong linkage disequilibrium, suggesting that these two polymorphisms convey the same information about the risk of presenting with PD. Genetic variation in the DRD2 gene may influence the risk of developing PD, thus confirming that the DRD2 gene is a susceptibility locus for PD.

Chronic vitamin E administration improves brachial reactivity and increases intracellular magnesium concentration in type II diabetic patients

Vascular disease accounts for the majority of the clinical complications in diabetes mellitus. As an exaggerated oxidative stress degree has been postulated as the link between diabetes mellitus and endothelial function, a possible positive effect of plasma vitamin E (Vit.E) administration on brachial reactivity could be postulated. Our study aims at investigating the possible effect of chronic Vit.E administration on brachial reactivity, oxidative stress indexes, and intracellular magnesium and calcium content in type II diabetic patients free of diabetic complications. Forty adult, type II diabetic patients were enrolled in the study, which was deigned as a double blind, randomized vs. placebo trial. At baseline all patients underwent the following tests: 1) anthropometric and metabolic examinations, 2) evaluation of oxidative stress indexes, 3) intracellular magnesium and calcium measurements, and 4) determination of arterial compliance and distensibility. Then, all patients were randomly assigned to Vit.E treatment at a dose of 600 mg/day (Evion Forte; n = 20) or placebo (n = 20) over 8 weeks. At the end of this treatment period, a complete reevaluation of the patients was made. Vit.E treatment was associated with a significant improvement in the percent change in brachial artery diameter (P<0.03) and oxidative stress indexes (P< 0.005). In the Vit.E group, the percent change in brachial artery diameter correlated positively with the percent change in oxidative stress indexes (oxidized/reduced glutathione, Trolox-equivalent antioxidant capacity, thiobarbituric acid reaction products, lipid peroxides) and intracellular cation content (magnesium and calcium). After adjustment for age, sex, body mass index, and wait/hip ratio, all of these correlations remained significant (P<0.03 for all). Furthermore, adjusting for glycosylated hemoglobin, plasma total cholesterol, and homeostatic model index, brachial artery diameter was still correlated with the percent change in oxidative stress indexes (P<0.04 for all). Nevertheless, the relationship between the percent change in brachial artery diameter and oxidative stress indexes was no longer significant after adjustment for intracellular Mg and Ca2+. In conclusion, our study demonstrates that chronic administration of Vit.E improves brachial artery reactivity in patients with type II diabetes mellitus. Such an effect seems mediated by a reduction in oxidative stress and a regulation of intracellular calcium and magnesium contents.

Apolipoprotein E polymorphisms and Parkinson's disease

The apolipoprotein E (APOE) gene polymorphism has been studied in Parkinson's disease (PD) with conflicting results. Recently, a newly described functional polymorphism in the regulatory region of the APOE gene, (-491 A/T), has been associated with late-onset Alzheimer's disease. We studied the association between these two polymorphisms of the APOE gene with PD in a sample of 126 PD patients and in 119 controls from the same geographic background. Allelic and genotypic frequencies were not different between PD cases and population controls for either the APOE or -491 A/T polymorphism. The age at onset of the disease was not different according to the specific genotypes of the two polymorphisms of the APOE gene.

Apolipoprotein E polymorphisms and the risk of nonlesional temporal lobe epilepsy

PURPOSE

To evaluate whether the inheritance of the apolipoprotein E (ApoE) epsilon4 allele is a risk factor for nonlesional temporal lobe epilepsy (TLE), and to determine whether the newly described -491 A/T ApoE polymorphism may independently affect the risk of nonlesional TLE.

METHODS

The study group consisted of 63 patients (35 women and 28 men; age at onset of epilepsy, 30.6 +/- 19.6 years; mean (+/-SD). All of them had received a diagnosis of nonlesional TLE after a detailed clinical, electroencephalographic, and brain magnetic resonance investigation. The ApoE polymorphisms were determined from blood samples by standard methods. The molecular study also was performed in 220 age- and sex-matched normal individuals.

RESULTS

There were no differences between TLE patients and controls in either allelic or genotypic frequencies of the ApoE and -491A/T polymorphisms. Moreover, no effect of ApoE or -491A/T polymorphisms was found on the age at onset and severity of epilepsy.

CONCLUSIONS

The allelic and genotypic frequencies of ApoE polymorphisms in Italian patients with nonlesional TLE are comparable to control values, indicating that ApoE polymorphisms are not a significant genetic risk factor for the occurrence of nonlesional TLE.

Baseline heart rate variability in healthy centenarians: differences compared with aged subjects (>75 years old)

Healthy centenarians have better anthropometric, endocrine, metabolic and immunological parameters than aged subjects (>75 years old). Heart rate variability (HRV) has been demonstrated to be a good index of the cardiac autonomic nervous system. It is not known whether there are any differences in cardiac autonomic nervous system activity between aged subjects and healthy centenarians. It is possible that differences in cardiac autonomic nervous system activity could represent one of a cluster of factors explaining the extreme survival of centenarians. Thus we aimed to answer the following question: is there any difference in baseline HRV parameters between aged subjects and healthy centenarians? Therefore power spectral analysis of HRV at baseline was investigated in 25 aged subjects (age > or = 75 years) and 30 healthy centenarians (age > or = 0 years). Anthropometric measurements were made in all subjects, fasting blood samples were drawn for metabolite determinations, and HRV was determined. Independent of age, gender, body mass index and fasting plasma noradrenaline and free 3,3',5-tri-iodothyronine concentrations, healthy centenarians had lower basal values for total power (1318+/-546 compared with 1918+/-818 ms(2); P<0.01) and the low-frequency component (33+/-21 compared with 50+/-11 normalized units; P<0.03) and a higher value for the high-frequency component (77+/-15 compared with 61+/-18 normalized units; P<0.05) than aged subjects. Consequently, the low-frequency/high-frequency ratio (0.43+/-0.07 compared with 0.91+/-0.05; P<0.02) was also lower in the healthy centenarians than in the aged subjects. Our study demonstrates that the basal low-frequency/high-frequency ratio, an indirect index of cardiac sympathovagal balance, is lower in healthy centenarians than in aged subjects.

A hypofibrinolytic state in overweight patients with cerebral venous thrombosis and isolated intracranial hypertension

Evidence suggests that isolated intracranial hypertension (iIH) is often associated with cerebral venous thrombosis (CVT). In eight patients referred to our Institution for iIH who were later shown to harbor CVT we have performed a comprehensive coagulation work-up, including genetic tests for inherited predisposition to thrombophilia, to clarify the etiology of sinus venous thrombosis. All subjects were women. All but one were overweight. There were high plasma concentrations of D dimer, thrombin-anti-thrombin complexes or prothrombin fragments 1 and 2, further supporting the neuroimaging diagnosis of CVT. Importantly, seven of eight cases had a raised level of plasminogen activator inhibitor 1, a well known inhibitor of fibrinolysis related to obesity. Tissue plasminogen activator levels were elevated accordingly. Factor V gene mutation was present in one subject, and the 20,210 prothrombin gene mutation was found in another individual. Three patients had elevated plasmatic levels of homocysteine. In conclusion, the present study provides solid evidence that impaired fibrinolysis probably related to overweight, acting in concert with other prothrombotic abnormalities, is involved in the pathogenesis of CVT presenting as iIH.

APOE and risk of cognitive impairment in multiple sclerosis

OBJECTIVES

The APOE gene polymorphism and the -491 A/T polymorphism in its regulatory region have been associated with an increased risk for developing Alzheimer's disease. We examined these polymorphisms in multiple sclerosis (MS) patients, to determine if a genetic predisposition may explain the risk for developing cognitive decline in MS.

MATERIAL AND METHODS

Eighty-nine relapsing-remitting and secondary progressive MS patients underwent to a full neuropsychological battery as well as to determination of APOE and -491 A/T polymorphisms. Genetic analysis was also performed in 107 population controls.

RESULTS

The APOE polymorphism was not associated with the risk of cognitive impairment in MS patients. The AA genotype of the -491 A/T polymorphism in the APOE regulatory region was more frequent in cognitively impaired than in cognitively preserved MS subjects.

CONCLUSION

The AA homozygous state of the -491 A/T polymorphism of the APOE regulatory region is associated with cognitive impairment in patients with MS.

Low plasma insulin-like growth factor-1 concentrations predict worsening of insulin-mediated glucose uptake in older people

OBJECTIVE

The relationship among insulin action, advancing age, and insulin like growth factor-1 (IGF-1) is poorly understood. To gain further insight, the predictive role that low plasma IGF-1 concentration may have on insulin- mediated glucose uptake in older persons was investigated.

DESIGN

The study was designed as a longitudinal, observational trial.

PARTICIPANTS

Fifty-eight healthy aged (73.1+/-9.4 years) subjects (31 males/27 females) were followed up for 12 months.

MEASUREMENTS

At baseline and at the end of the follow-up, insulin-mediated glucose uptake was assessed by euglycemic glucose clamp and plasma total IGF-1 and IGF-binding protein 3 (IGF-BP-3) in each subject, and concentrations were determined.

RESULTS

At baseline, plasma IGF-1 concentrations correlated with whole body glucose uptake (WBGD) (r = 0.39, P < .003), insulin-stimulated glucose oxidation (GOX) (r = 0.35, P < .009), and non-oxidative glucose metabolism (r = 0.37, P < .007). Such correlations were also independent of age, sex, body fat, and waist/hip ratio. Fasting plasma total IGF-1 concentrations (84+/-56 vs 63+/-44 microg/L, P < .040), plasma IGF-1/IGF-BP3 molar ratio (0.13+/-0.05 vs 0.10+/-0.03 P < .050), and WBGD (34.8+/-5.0 vs 23.1+/-4.6 micromol/kg x min, P < .010) were more elevated at baseline than at the end of the follow-up. Low baseline fasting plasma IGF-1 concentration (RR = 1.5, 95%CI = 1.3-1.7) and plasma IGF-1/IGFBP-3 molar ratio (RR = 1.4, 95% CI = 1.3-1.8) predicted a decline in WBGD. The predictive role of plasma IGF-1 on age-related decline in WBGD was independent of age, sex, body fat, waist/hip ratio, and degree of physical activity (model 1), or of fasting plasma free fatty acid and triglyceride concentrations, LDL/HDL ratio, and basal adjusted respiratory quotient (model 2). Finally, low plasma IGF-1 concentration predicts a decline in WBGD independent of body fat, free fatty acids, waist/hip ratio, and basal adjusted respiratory quotient (model 3).

CONCLUSION

Our study demonstrates that fasting plasma IGF-1 concentration may have a modulatory role on insulin action in older people. This finding might prompt an evaluation of the direct effect of IGF-1 administration on insulin sensitivity in older adults.

Dopamine D2 receptor gene polymorphism and the risk of levodopa-induced dyskinesias in PD

OBJECTIVE

To investigate whether polymorphisms in the genes for dopamine receptors D1 and D2 are associated with the risk of developing peak-dose dyskinesias in PD.

BACKGROUND

Peak-dose dyskinesias are the most common side effects of levodopa therapy for PD. The identified predictors may only partially account for the risk of developing peak-dose dyskinesias because a substantial proportion of patients never develop peak-dose dyskinesias. Genetic factors could play a role in determining the occurrence of peak-dose dyskinesias.

METHODS

A case-control study of 136 subjects with sporadic PD and 224 population control subjects. We studied three polymorphisms involving the dopamine receptor D1 gene and one intronic short tandem repeat polymorphism of the dopamine receptor D2 gene.

RESULTS

The polymorphisms of the dopamine receptor D1 gene were not associated with the risk of developing PD or peak-dose dyskinesias. The 15 allele of the polymorphism of the dopamine receptor D2 gene was more frequent in parkinsonian subjects than in control subjects. More important, the frequency of both the 13 allele and the 14 allele of the dopamine receptor D2 gene polymorphism was higher in nondyskinetic than in the dyskinetic PD subjects. The risk reduction of developing peak-dose dyskinesias for PD subjects carrying at least 1 of the 13 or 14 alleles was 72% with respect to the PD subjects who did not carry these alleles.

CONCLUSIONS

Certain alleles of the short tandem repeat polymorphism of the dopamine receptor D2 gene reduce the risk of developing peak-dose dyskinesias and could contribute to varying susceptibility to develop peak-dose dyskinesias during levodopa therapy.

Autosomal recessive hereditary motor and sensory neuropathy with focally folded myelin sheaths (CMT4B)

Hereditary motor and sensory neuropathy with focally folded myelin sheaths, or Charcot-Marie-Tooth neuropathy type 4B (CMT4B), is a distinct clinical and genetic entity belonging to the heterogeneous group of autosomal recessive demyelinating neuropathies. We first described a large inbred pedigree with 10 patients affected by CMT4B, which enabled us to uncover the genetic findings, clinical spectrum, and natural history of such a disorder. The clinical picture was characterized by infantile onset with progressive symmetric distal and proximal muscular weakness. Using homozygosity mapping and haplotype sharing analysis, we found evidence of linkage of chromosome 11q23. We then identified a second unrelated family in which two individuals were affected with CMT4B. Although the clinical findings were similar to those previously reported, we excluded the disease locus segregating in this smaller pedigree from the 11q23 region. We thus provided evidence for a second locus causing the CMT4B phenotype. All these findings indicate that CMT4B seems to be phenotypically quite homogeneous, but is genetically heterogeneous.

Emotion-induced myoclonic absence-like seizures in a patient with inv-dup(15) syndrome: a clinical, EEG, and molecular genetic study

We have described a clinical EEG and molecular genetic study of a 9-year-old boy with inv-dup(15) syndrome in whom seizures were induced by emotionally gratifying stimuli. The reflex seizures began 5-20 s after the onset of repeated cheek-kissing from his mother or after viewing of pleasant or funny events. They were characterized by bilateral discharges involving mainly the temporal regions and evolving into myoclonic absence-like seizures. Nonemotional stimuli, such as a pinch, sucking or rubbing his cheeks, or the sound of the kiss alone, failed to provoke seizures. The seizures were resistant to antiepileptic (AED) treatments. Molecular genetic investigations revealed a correct methylation pattern of the chromosomes 15, and three copies (two maternal and one paternal) of the segment 15q11-q13, including the GABRb3 gene. We hypothesize that an overexpression of cerebral gamma-aminobutyric acid (GABA)-mediated inhibition accounts for the severe epilepsy that we observed in this patient.

Pharmacodynamics of the long-duration response to levodopa in PD

OBJECTIVE

To determine the latency, magnitude, and duration of the long-duration response (LDR) to levodopa in PD in relationship to the administration of levodopa at different interdose intervals.

METHODS

In six patients with PD, two different 15-day treatment regimens were used in which the drug was administered with interdose intervals of 24 or 8 hours.

RESULTS

The LDR built up within a few days with either regimen, but a faster rate of administering levodopa shortened the latency to the appearance of a sustained LDR. Once a sustained response had been reached, the magnitude of the LDR showed a stable ceiling effect that was independent of the levodopa schedule. After discontinuation of treatment, the decay of the LDR was similar for both regimens.

CONCLUSIONS

The system underlying the LDR to levodopa may be completely saturated when a sustained response has been fully developed. The intervals between doses of levodopa shorter than the interval effective to reach a sustained LDR should not be used in the clinical management of patients with PD because the antiparkinsonian benefit deriving from the LDR is already maximal and briefer intervals do not provide a greater benefit.

Effects of different insulin infusion rates on heart rate variability in lean and obese subjects

The low-frequency to high-frequency ratio (LF/HF ratio) is an index of cardiac sympathovagal balance. We hypothesized that insulin might also stimulate the LF/HF ratio. Thus, 15 lean and 15 obese subjects were studied. Each subject underwent sequential hyperinsulinemic clamps (insulin infusion rate 0.50, 1, and 2 mU/kg x min) while the heart rate was recorded by the Holter technique continuously. Indirect calorimetry allowed determination of the respiratory quotient (Rq) and substrate oxidation. The leg blood flow (LBF), leg vascular resistance (LVR), and plasma norepinephrine concentration were also measured. In seven lean subjects, hyperinsulinemic clamps were repeated along with propranolol infusion (0.1 mg x kg(-1) as an intravenous bolus dose followed by continuous intravenous infusion of 0.5 mg x kg(-1) x min(-1) throughout the study). Lean subjects had better insulin action than obese subjects. Insulin infusion was associated with an increase of the deltaLF/HF ratio in both lean (P < .001 for time-dependent changes) and obese (P < .02 for time-dependent changes) subjects; however, the extent of insulin-mediated stimulation of the LF/HF ratio was greater in lean versus obese subjects. Insulin infusion did not significantly affect HF values in both groups. Independently of gender, body fat, changes in the plasma norepinephrine concentration, LBF, and LVR, the deltaLF/HF ratio at the end of the fastest insulin infusion (0.8 +/- 0.2 v 0.3 +/- 0.2, P < .04) was still greater in lean versus obese subjects. The deltaLF/HF ratio was also more stimulated during insulin versus insulin + propranolol infusion in lean subjects. In conclusion, insulin stimulates the LF/HF ratio in both lean and obese subjects and thus produces a shift in the cardiac autonomic nervous system activity toward sympathetic predominance.

Prognostic importance of insulin-mediated glucose uptake in aged patients with congestive heart failure secondary to mitral and/or aortic valve disease

Previous studies have demonstrated that insulin resistance is a common feature of congestive heart failure (CHF), but the clinical significance of such insulin resistance is still debated. We tested the hypothesis that insulin-mediated glucose uptake (IMGU) is a prognostic factor in CHF in aged patients. For this purpose 174 aged patients with CHF participated in a cross-sectional and a longitudinal study of 24 months' duration. In this latter study survival analysis was calculated comparing subjects at the first and second tertile of IMGU with those at third tertile. All subjects underwent anthropometric (body mass index, waist/hip ratio), cardiovascular (arterial blood pressure, 24-hour Holter monitoring, peak VO2, left ventricular ejection fraction, echocardiography), and metabolic (determination of fasting plasma glucose, insulin, catecholamine, free fatty acids, tumor necrosis factor-alpha concentrations, and assessment of IMGU by euglycemic hyperinsulinemic glucose clamp) investigations. In the cross-sectional study, IMGU correlated with age (r = -0.33, p <0.001), body mass index (r = -0.46 p <0.001), ventricular premature complexes (r = -0.78, p <0.001), left ventricular ejection fraction (r = -0.15, p <0.05), fasting plasma norepinephrine (r = -0.75, p <0.001), tumor necrosis factor-alpha (r = -0.45, p <0.001), free fatty acids (r = -0.54, p <0.001), and peak VO2 (r = 0.67, p <0.001). In the longitudinal study patients at the first and second tertile of IMGU had a lower probability of survival than patients at the third tertile (p <0.03). Cox regression analysis showed IMGU to be a prognostic factor independent of fasting plasma norepinephrine, tumor necrosis factor-alpha, free fatty acid concentration, New York Heart Association class, peak VO2, and left ventricle ejection fraction (relative risk 1.1, 95% confidence intervals 1.0 to 2.1). In conclusion, our study demonstrates that insulin resistance is a common feature of CHF most likely due to elevated plasma norepinephrine and tumor necrosis factor-alpha concentrations, and that IMGU is an independent prognostic factor in CHF.

Idiopathic generalized epilepsies with versive or circling seizures

OBJECTIVES

To describe the electroclinical features of the idiopathic generalized epilepsies (IGEs) with versive or circling seizures.

METHODS

Sixteen patients with versive or circling seizures and interictal electroclinical features of IGE were studied. Patients with insufficient clinical or imaging data, with a follow-up period less than 1 year or with partial seizures in addition to the versive or circling ones were excluded from the study. All patients underwent full interictal clinical and neurophysiological studies. The EEG patterns of 13 versive or circling seizures from 4 patients were also analyzed.

RESULTS

A specific IGE syndrome was recognized in 9 out of the 16 patients (56%). More specific, 1 patient had childhood absence epilepsy (CAE), 4 had juvenile absence epilepsy (JAE), and 4 had juvenile myoclonic epilepsy (JME). No specific IGE syndrome was recognizable in the remaining 7 patients (44%). These 7 patients had a juvenile epileptic syndrome (mean age at onset of seizures was 15.7 years) characterized by versive or circling seizures followed or not by generalized tonic-clonic fits. Three main EEG patterns were identified during versive or circling seizures: 1) generalized spike-and-wave discharges at 3-4 cps; 2) generalized polyspike-and-wave discharges at 1 to 2.5 cps beginning with generalized fast activity at 12-14 cps, and 3) generalized spike-and-wave discharges at 3-4 cps intermingled with fast activity at 12-14 cps. Most patients had good response to treatment on a single drug regimen (mainly valproic acid).

CONCLUSIONS

Versive or circling seizures may occur in the context of an IGE. Although many individuals share the features of different IGE syndromes including CAE, JAE and JME, a consistent number of patients, who show circling or versive seizures solely, remain without a specific syndromic diagnosis. When occurring in the context of IGE, circling or versive seizures do not worsen the prognosis.

Hyperekplexia in a patient with a brainstem vascular anomaly

OBJECTIVES

To describe a patient with a clinical picture suggestive of idiopathic hyperekplexia (IH), who was later found to harbour a subtle brainstem vascular anomaly.

PATIENT

A 35-year-old man, 4 years earlier, developed sudden jumping and falling in response to unexpected sensory stimuli.

RESULTS

Neurological examination was normal. Electromyography showed an excessively large and non-habituating motor startle response. There were no mutations of the alpha1 subunit of the inhibitory glycine receptor which cause hereditary hyperekplexia. Although all these findings were consistent with a diagnosis of IH, a blink reflex study showed an enhanced recovery curve suggestive of a brainstem lesion. A detailed MRI study revealed a subtle vascular anomaly involving the lower brainstem.

CONCLUSION

This is the first report of sporadic hyperekplexia related to a brainstem vascular anomaly. Subtle damage to the brainstem should always be excluded in patients with sporadic hyperekplexia, regardless of the coexistence of additional clear-cut neurological symptoms.

Loss of long-duration response to levodopa over time in PD: implications for wearing-off

OBJECTIVE

To determine the modifications of the long-duration response to levodopa in PD over a 1-year period.

BACKGROUND

The development of predictable motor fluctuations in PD has been attributed mainly to modifications over time of the short-duration response to levodopa, whereas the role of the long-duration response has not been widely investigated.

METHODS

In 17 patients with PD the authors examined prospectively both the short-duration response and the long-duration response to levodopa under standardized conditions on two different occasions separated by a period of approximately 1 year (11.7 +/- 3.6 months).

RESULTS

At the end of the follow-up period, the short-duration response increased in magnitude but did not change significantly in duration. A total of 24% of patients lost the long-duration response 1 year after their first examination, but a sustained long-duration response could be reestablished by shortening the interdose interval for levodopa intake. Moreover, the duration of the long-duration response after discontinuation of treatment became significantly shorter during 1 year.

CONCLUSION

Modifications of the long-duration response may have a pivotal role in generating a fluctuating response, and suggest that therapeutic strategies based on maintenance of the long-duration response should be sought to avoid the appearance of motor fluctuations.

Intralipid infusion combined with propranolol administration has favorable metabolic effects in elderly malnourished cancer patients

Previous studies have shown that an elevated basal metabolic rate (BMR) is present in elderly malnourished cancer patients. A possible dysfunction of the autonomic nervous system needs to be demonstrated. In aged weight-losing cancer patients (n = 40), aged non-weight-losing cancer patients (n = 30), and aged weight-losing noncancer patients (n = 18), the baseline BMR and heart rate variability were studied. Aged weight-losing cancer patients (n = 40) underwent bioimpedance analysis, ambulatory electrocardiographic monitoring with analysis of heart rate variability, and determination of the BMR. Then, the patients received infusion of Intralipid (Pharmacia, Uppsala, Sweden) without and with propranolol (6 days of 40 mg twice daily) administration. At baseline, a simple correlation between the BMR and the low-frequency component (LF) (r = .42, P < .006) and LF to high-frequency (HF) ratio (r = .51, P < .001) was found. After propranolol administration, the percent decline in the BMR was significantly correlated with the percent decline in the LF (r = .39, P < .01) and LF/HF ratio (r = .53, P < .001). The percent decline in the BMR was not correlated with the HF (r = .13, P < .34) or the plasma noradrenaline concentration (r = .21, P < .20) at any time. With regard to the BMR and substrate oxidation, 6-day propranolol administration plus Intralipid infusion produced the strongest decline in the BMR. This study demonstrates that autonomic nervous system dysfunction occurs and is responsible for the elevated BMR in elderly cancer patients, propranolol administration rectifies the autonomic dysfunction, and Intralipid infusion combined with propranolol administration is useful for enhancing the daily caloric intake without a strong increase in energy expenditure.

Mean arterial blood pressure and serum levels of the molar ratio of insulin-like growth factor-1 to its binding protein-3 in healthy centenarians

OBJECTIVE

Healthy centenarians have a greater molar ratio of plasma insulin-like growth factor-1 to insulin-like growth factor binding protein-3 than that of aged subjects. We investigated the question of whether differences in mean arterial pressure and in this plasma ratio were related in healthy centenarians.

SUBJECTS AND METHODS

We studied 52 subjects in total, 30 aged subjects (70-99 years) and 22 healthy centenarians (> 100 years) to determine differences in mean arterial pressure, endothelial function and intracellular cation levels.

RESULTS

In the healthy centenarians, the molar ratio of fasting plasma insulin-like growth factor-1 to its binding protein-3 was significantly correlated with mean arterial pressure (r = -0.66, P < 0.001). Baseline (19.3 +/- 1.5 versus 27.6 +/- 2.2 mumol/l, P < 0.05) and L-arginine-stimulated percentage increases in the plasma total nitrate: nitrite ratio (67 +/- 3.4 versus 48 +/- 4.5%, P < 0.03) were greater in the healthy centenarians than in the aged subjects. An L-arginine bolus elicited an increase in forearm blood flow which was correlated with the percentage increase in the plasma total nitrate: nitrite ratio (r = 0.79, P < 0.001) and with the fasting erythrocyte magnesium concentration (r = 0.80, P < 0.001) in healthy centenarians. Both correlations remained significant (P < 0.01) after adjustment for sex, body mass index and the waist: hip ratio. Moreover, the fasting plasma molar ratio of insulin-like growth factor-1 to its binding protein-3 was correlated with the percentage increase in forearm blood flow (r = 0.59, P < 0.005) and with the percentage increase in the plasma total nitrate: nitrite ratio (r = 0.54, P < 0.009) in healthy centenarians. The centenarians had higher baseline total erythrocyte magnesium and lower calcium concentrations than the aged subjects. The addition of insulin growth factor-1 to the incubation medium increased the total intracellular erythrocyte magnesium content and decreased the calcium content in both groups of subjects. Nevertheless, the percentage increase in total erythrocyte magnesium (33 +/- 3.8 versus 12 +/- 3.4%, P < 0.03) and decline in intracellular calcium (17 +/- 2.8 versus 8 +/- 3.1%, P < 0.02) concentrations were greater in the healthy centenarians than the aged subjects.

CONCLUSION

In healthy centenarians, insulin-like growth factor-1 may preserve endothelial function and modulate the intracellular cation content, thus contributing to a lower mean arterial pressure than that in aged subjects.

Mild non-lesional temporal lobe epilepsy. A common, unrecognized disorder with onset in adulthood

OBJECTIVE

To compare mild vs. severe non-lesional temporal lobe epilepsy (TLE).

METHODS

Data from 104 consecutive patients with non-lesional TLE were reviewed. Seventy-three of the 104 fulfilled the criteria for inclusion in this study of a follow-up period longer than three years at our Institute. Patients were considered to have a mild TLE if they were seizure free for at least three years after appropriate antiepileptic medication, or had rare (< or = 2/year) complex partial or secondarily generalized seizures for at least three years with or without appropriate antiepileptic therapy. Clinical, EEG and MRI data of mild vs. severe non-lesional TLE patients were compared on the basis of a cross-sectional study design.

RESULTS

Of the 73 patients with non-lesional TLE included in the study, 43 (59%) had mild TLE, and 30 (41%) had severe TLE. Duration of epilepsy was significantly shorter (mean 15.2 +/- 10.5 years vs. 26.4 +/- 13.2 years) and age at onset was significantly higher (mean 34.3 +/- 15.3 years vs. 7.8 +/- 6.8 years) in mild than in severe TLE group. Patients with mild TLE had also a significantly higher prevalence of positive family history of epilepsy (37.2% vs. 10%), and a significantly lower occurrence rate of febrile convulsions (FC) (4.7% vs. 33.3%), mesial temporal sclerosis (MTS) (6.9% vs. 36.7%), and intelligence deficiency (0% vs. 20%). In mild TLE there was also a significantly high rate (58.1 vs. 0%) of delayed diagnosis (from 1 to 28 years), because of misdiagnosis (39.5%) or no medical counseling (18.6%).

CONCLUSIONS

Mild non-lesional TLE is a common, unrecognized disorder mainly characterized by both onset in adulthood and high prevalence of familial history of epilepsy. The present findings suggest that mild non-lesional TLE may represent a clinical entity different from severe non-lesional TLE.

Spinal muscular atrophy due to an isolated deletion of exon 8 of the telomeric survival motor neuron gene

Patients with autosomal recessive spinal muscular atrophy (SMA) usually carry a homozygous deletion of exons 7 and 8 of the telomeric survival motor neuron (SMN(T)) gene, although an isolated deletion of SMN(T) exon 8 has never been found. We now report on 2 patients with the typical features of SMA types II and III, who carried a homozygous deletion of SMN(T) exon 8 but retained SMN(T) exon 7. Importantly, to exclude a sequence conversion event of telomeric exon 8, we amplified a fragment that spanned exons 7 and 8 of the SMN gene. The resulting 1,010-base pair (bp) fragments were subjected to nested polymerase chain reaction (PCR) of exon 7. The subsequent restriction analysis failed to show any products of telomeric exon 7, as the site for primer 541C1120 was lost in both alleles. These findings indicate a homozygous deletion of SMN(T) exon 8. Direct sequencing of the cloned 1,010-bp fragment further confirmed that these 2 SMA patients did not possess telomeric exon 8. The more severely affected child also showed a deletion of the neuronal apoptosis inhibitory protein (NAIP) gene. The present findings provide evidence that an isolated deletion of SMN(T) exon 8 is associated with the milder subtypes of SMA. Our data also demonstrate that the additional deletion of the NAIP gene exacerbates the severity of the disease.

Kufs' disease presenting as late-onset epilepsia partialis continua

A 64-year-old woman, who had no personal or family history of neurologic diseases, had an 18-month history of epilepsia partialis continua (EPC) associated with a moderate intellectual deterioration and subtle extrapyramidal rigidity. There was no photosensitive response. A thorough laboratory investigation was unremarkable. A biopsy of the rectal mucosa revealed abundant fingerprint profiles diagnostic of Kufs' disease (KD). Our case expands the clinical picture of KD and suggests that such a diagnosis should be considered in adult-onset EPC.

Lowering fatty acids potentiates acute insulin response in first degree relatives of people with type II diabetes

Studies have shown that a high plasma non-esterified fatty acid concentration may inhibit glucose induced insulin secretion in vitro and in vivo. The effect of lowering the fatty acid concentration on the acute insulin response was investigated in first degree relatives of people with Type II diabetes in a double-blind, randomised, placebo-controlled trial. Fifty first degree relatives of people with Type II diabetes volunteered for the study. Twenty five were given acipimox (250 mg/day, four times daily) and 25 placebo. The group treated with acipimox had a lower 2-h plasma glucose concentration (6.1 +/- 0.2 vs 7.7 +/- 0.3 vs mmol/l, p < 0.01); better insulin-mediated glucose uptake (35.4 +/- 0.5 vs 28.3 +/- 0.4 mumol/kg fat free mass per min, p < 0.01), acute insulin response (68 +/- 4.4 vs 46 +/- 7.3 mU/l, p < 0.01) and respiratory quotient (0.81 +/- 0.02 vs 0.77 +/- 0.03, p < 0.05); and a rise in the plasma glucagon (164 +/- 63 vs 134 +/- 72 ng/1, p < 0.05), growth hormone (1.31 +/- 0.13 vs 0.97 +/- 0.21 microgram/l, p < 0.03) and cortisol (325 +/- 41 vs 284 +/- 139 nmol/l, p < 0.05) concentrations. The difference in the acute insulin response persisted, even after adjustment for the 2-h plasma glucose concentration, insulin-mediated glucose uptake, the fasting plasma glucagon concentration and the growth hormone concentration (p < 0.05). In a subgroup of eight patients acipimox was compared with acipimox plus intralipid. The acute insulin response (44 +/- 5.1 vs 71 +/- 5.3 mU/l, p < 0.01) and the insulin-mediated glucose uptake (27.4 +/- 0.4 vs 36.7 +/- 0.5 mumol/kg fat free mass per min, p < 0.003) were lower with acipimox plus intralipid treatment than with acipimox alone. It is concluded that long term acipimox treatment lowers the plasma fasting free fatty acid concentration and improves the acute insulin response and the insulin mediated glucose uptake.

CAG repeat length and clinical features in three Italian families with spinocerebellar ataxia type 2 (SCA2): early impairment of Wisconsin Card Sorting Test and saccade velocity

We report on the clinical, neuropsychological, neurophysiological, computerized eye movement, magnetic resonance imaging (MRI) and molecular findings from 17 individuals affected with spinocerebellar ataxia type 2 (SCA2) belonging to three families. The average age at onset of the symptoms was 35.6, 11.9 (mean, SD) years. The mean age at onset of the symptoms in the parents was 44.8, 8.2 years, and in the offspring it was 28.7, 7.2 years. In 12 parent-child pairs, the mean anticipation was -15.75, 9.1 years (range -8.1 to -23.3 years, t = -4.9, P = < 0.002). The mutated SCA2 alleles ranged from 38 to 42 CAG repeats, while the normal alleles ranged from 22 to 24 repeats, with 97% of the alleles having 22 repeats. Small differences in the number of CAG repeats influenced the age at onset and rate of progression of the disease considerably. Indeed, patients presenting with their first symptom at an age of 35 years or later with a slower course of the disease harboured between 38 and 39 repeats. In contrast, patients carrying > or = 40 CAG repeats manifested the disease prior to 30 years of age and had a faster disease progression toward incapacity. The presenting symptom was always gait ataxia. Slow saccades occured from the beginning of the disease despite normal delay, accuracy and smooth pursuit eye movements. The neuropsychological study showed early and selective impairment of conceptual reasoning ability, as detected by the Wisconsin Card Sorting Test (WCST). It is noteworthy that a significant mutual relationship was observed between performance on the WCST and saccade velocity. All of these findings favour the hypothesis that the disease process of SCA2 in regions other than the cerebellum and brain stem affects severely and early those cortical structures involved in the control of both visually guided saccades and WCST performance.

Usefulness of latero-orbital electrodes in detecting interictal epileptiform activity--a study of 60 patients with complex partial seizures

OBJECTIVES

The use of latero-orbital (Lo) electrodes is a routine practice in any EEG laboratory to evaluate eye motion, but there are no data about their usefulness in revealing interictal epileptiform abnormalities.

METHODS

In 60 consecutive patients (27 men, 33 women, mean age 36.8 years, range 17-72) with complex partial seizures, we prospectively evaluated the utility of Lo electrodes in comparison with anterior temporal (AT) electrodes, for the detection of interictal epileptiform discharges (SW).

RESULTS

No epileptiform abnormality was seen in 4/60 patients. Both AT and Lo electrodes were significantly superior to 10-20 electrodes for detection of both patients and foci. Indeed, the standard 10-20 system alone allowed the detection of only 39 independent epileptiform foci in 35/56 (63%) patients, while AT and Lo electrodes were necessary for detection of 23 epileptiform foci in the remaining 21/56 (37%) patients. Importantly, there was no statistically significant difference in detection between AT and Lo electrodes.

CONCLUSIONS

Recordings from Lo electrodes are comparable to those from AT electrodes and are useful for localizing interictal temporal spiking activity. Lo electrodes may be substituted for basal electrodes in the day-to-day evaluation of patients with complex partial seizures.

Advancing age and insulin resistance: role of plasma tumor necrosis factor-alpha

In 70 healthy subjects with a large age range, the relationships between plasma tumor necrosis factor-alpha (TNF-alpha) and body composition, insulin action, and substrate oxidation were investigated. In the cross-sectional study (n = 70), advancing age correlated with plasma TNF-alpha concentration (r = 0.64, P < 0.001) and whole body glucose disposal (WBGD; r= -0.38, P < 0.01). The correlation between plasma TNF-alpha and age was independent of sex and body fat (BF; r = 0.31, P < 0.01). Independent of age and sex, a significant relationship between plasma TNF-alpha and leptin concentration (r = 0.29, P < 0.02) was also found. After control for age, sex, BF, and waist-to-hip ratio (WHR), plasma TNF-alpha was still correlated with WBGD (r = -0.33, P < 0.007). Further correction for plasma free fatty acid (FFA) concentration made the latter correlation no more significant. In a multivariate analysis, a model made by age, sex, BF, fat- free mass, WHR, and plasma TNF-alpha concentrations explained 69% of WBGD variability with age (P < 0.009), BF (P < 0.006), fat-free mass (P < 0.005), and plasma TNF-alpha (P < 0.05) significantly and independently associated with WBGD. In the longitudinal study, made with subjects at the highest tertiles of plasma TNF-alpha concentration (n = 50), plasma TNF-alpha concentration predicted a decline in WBGD independent of age, sex, BF, WHR [relative risk (RR) = 2.0; 95% confidence intervals (CI) = 1.2-2.4]. After further adjustment for plasma fasting FFA concentration, the predictive role of fasting plasma TNF-alpha concentration on WBGD (RR = 1.2; CI = 0.8-1.5) was no more significant. In conclusion, our study demonstrates that plasma TNF-alpha concentration is significantly associated with advancing age and that it predicts the impairment in insulin action with advancing age.

Oxidative stress and advancing age: results in healthy centenarians

OBJECTIVE

Our study aims at investigating the degree of oxidative stress in centenarians

DESIGN

Indices of oxidative stress (reaction products of malondialdehyde with thiobarbituric acid (TBARS) and lipid hydroperoxides (LPO)), and plasma concentrations of antioxidant defenses (plasma vitamin E and C concentrations and reduced/oxidized glutathione ratio (GSH/GSSG)) were determined.

SUBJECTS

Eighty-two subjects volunteered for the study. They were divided into three groups: (1) adults (<50 years of age, n=30); (2) aged subjects (70-99 years, n=30); (3) centenarians (age > or=100 years, n=22).

MEASUREMENTS

TBARS and LPO, plasma vitamin E and C concentrations, and plasma GSH/GSSG ratio were determined. Insulin action was assessed by euglycemic hyperinsulinemic glucose clamp.

MAIN RESULTS

TBARS (0.44+/-0.07 vs 0.31+/-.05 nmol malondialdehyde/mL plasma, P=.020) and LPO (0.36+/-0.05 vs 0.31+/-.04 micromol/L, P=.050) were lower in centenarians than in aged subjects. In contrast, plasma GSH/GSSG ratio (0.82+/-0.09 vs 1.17+/-.06, P=.010), vitamin C (72.3+/-4.6 vs 59.4+/-3.8 micromol/L P=.010), and vitamin E (29.1+/-2.2 vs 24.4+/-2.3 micromol/L P=.050) concentrations were more elevated in centenarians than in aged subjects. Differences in daily vegetable intake, in fasting plasma glucose and free fatty acid (FFA) concentrations, and in insulin action are significant determinants of degree of oxidative stress. A specific genetic background in centenarians might also provide a possible explanation.

CONCLUSIONS

The degree of oxidative stress is lower in healthy centenarians than in aged subjects.

Randomized trial comparing two different high doses of methylprednisolone in MS: a clinical and MRI study

OBJECTIVE

To assess the efficacy of two different high doses of intravenous methylprednisolone (IVMP) for the treatment of relapses in MS.

BACKGROUND

IVMP is the treatment of choice for MS relapses, but it is unknown whether its effects are dose related.

METHODS

We conducted a double-blind, randomized study. Follow-up included serial clinical and MRI recordings at baseline and at 7, 15, 30, and 60 days after the beginning of treatment. Outcome measures were the number of brain and cervical spinal cord MRI contrast-enhancing lesions, and the Expanded Disability Status Scale score.

RESULTS

Both treatment regimens improved clinical scores and reduced the number of MRI enhancing lesions during the follow-up period. The higher dose of IVMP was significantly more effective than the lower dose in reducing the number of MRI contrast-enhanced lesions at 30 and 60 days, mainly by decreasing the rate of new lesion formation.

CONCLUSIONS

The higher dosage of IVMP has a more powerful and prolonged action in maintaining blood-brain barrier integrity after a clinical relapse.

Effect of metformin on food intake in obese subjects

BACKGROUND

It has been hypothesized that metformin inhibits food intake, but in humans such effect needs to be demonstrated. Our study aims at investigating the effect of metformin administration on food intake in obese, non-diabetic, normotensive patients.

METHODS

Thirty patients underwent a double-blind, randomized study. Placebo (P; n = 15) and metformin (M; n = 15) were both given for 15 days, and food intake (FI) was recorded at baseline and in the last 4 days of each treatment period.

RESULTS

M administration allowed a stronger decline in body weight (BW) (-2.8 +/- 1.6 vs. -0.3 +/- 0.4 kg P < 0.01), body fat (BF) (-1.4 +/- 1.2 vs. -0.3 +/- 1.1 kg P < 0.01), plasma leptin concentration (-5.2 +/- 8.9 vs. -1.8 +/- 10.4 ng mL-1 P < 0.05) and FI (-642 +/- 491 vs.-70 +/- 1165 kJ per 24 h P < 0.01) than P. In M-treated subjects, changes in FI significantly correlated with those in BW (r = 0.63, P < 0.007) and BF (r = 0.74, P < 0.001). Independently of sex and change in BF, the changes in FI and in fasting plasma leptin concentration (r = 0.58, P < 0.01) were still correlated.

CONCLUSION

Our study suggests that metformin administration is useful to inhibit FI and to lower BW and BF in obese non-diabetic patients.

Myoclonic absence-like seizures and chromosome abnormality syndromes

PURPOSE

We explored the relationship between myoclonic absence seizures (MAS) and underlying chromosome disorders.

METHODS

Among 14 patients with MAS observed in three centers, 5 had typical cryptogenic myoclonic absence epilepsy (MAE), 2 had MAS associated with other seizure types (1 with signs of a neuronal migration abnormality and 1 with signs of a metabolic disorder), and 7 had MAS, with or without other seizure types, complicating a chromosome abnormality syndrome-2 with trisomy 12p, 4 with Angelman syndrome, and 1 with inv dup (15).

RESULTS

In the 7 patients with chromosomopathy, MAS appeared at a mean age of 2.9 years (range 4 months to 6 years 6 months), had a duration of 4-20 s, and were accompanied by reduced awareness and rhythmic myoclonic jerks involving proximal limb muscles. Ictal EEG showed 2- to 3-Hz generalized spike-and-wave discharges.

CONCLUSIONS

In these patients, MAS differed slightly from those of typical MAE: age of onset was earlier, absences were of shorter duration, and no clear increase in muscular tone was noted. Abnormal expression of genes codifying for the subfamily of K+ channels and for gamma-aminobutyric acid-3 subunit receptors (GABRB3), both located in the chromosome segments involved in the chromosomopathies presented by our patients, could be responsible for the same generalized seizure type. Chromosome analysis should be performed in patients with mental retardation and MAS, especially when the ictal pattern does not completely overlap that observed in MAE.

Genetic heterogeneity in autosomal recessive hereditary motor and sensory neuropathy with focally folded myelin sheaths (CMT4B)

Hereditary motor and sensory neuropathy with focally folded myelin sheaths, or Charcot-Marie-Tooth disease neuropathy type 4B (CMT4B), is a distinct clinical and genetic entity belonging to the heterogeneous group of autosomal recessive demyelinating neuropathies. We previously described a large pedigree with CMT4B and found evidence of linkage to chromosome 11q23. We now describe a second, unrelated family in which two individuals were affected with CMT4B. We exclude the disease locus segregating in this smaller pedigree from the 11q23 region as well as from most of the regions where other CMT loci have been mapped. We thus provide evidence for a second locus causing the CMT4B phenotype.

Plasma sex hormones are significantly associated with plasma leptin concentration in healthy subjects

OBJECTIVE

In humans a sexual dimorphism of plasma leptin concentration has been demonstrated but its significance remains to be established. Sex hormones may have a role.

PATIENTS

Eighty healthy, non-obese subjects (41M/39F) were studied.

MEASUREMENTS

In the whole group of subjects plasma sex hormones, leptin and insulin concentrations were determined, body fat content assessed by bioimpedance analysis, body fat distribution evaluated and insulin-mediated glucose uptake measured by euglycemic hyperinsulinemic glucose.

RESULTS

After adjustment for age, gender, amount of body fat, waist/hip ratio (WHR) and fasting plasma insulin concentration, fasting plasma leptin was still significantly correlated with plasma DHEAS (r = -0.30, P < 0.006), oestradiol (r = 0.53, P < 0.001) and testosterone (r = -0.43, P < 0.001) in all subjects (n = 80). Independently of age, amount of body fat and WHR, fasting plasma leptin concentration correlated with plasma oestradiol (r = 0.38, P < 0.01) and total testosterone (r = -0.58, P < 0.001) in males (n = 41) and with fasting plasma oestradiol (r = 0.48, P < 0.002) in females (n = 39). To investigate the independent contribution of anthropometric and hormonal variables to fasting plasma leptin concentration, a multivariate stepwise regression analysis with fasting plasma leptin concentration as dependent variable was made. In the entire group (n = 80), the whole model explained 43% of fasting plasma leptin concentration with fasting plasma insulin, total testosterone and oestradiol concentrations significantly and independently associated with plasma leptin concentration. In this model, fasting plasma DHEAS, testosterone and oestradiol explained 25% of the variability in plasma leptin concentration.

CONCLUSION

Our study demonstrates that plasma sex hormone concentrations are associated with plasma leptin concentration.

Preserved antilipolytic insulin action is associated with a less atherogenic plasma lipid profile in healthy centenarians

OBJECTIVE

Recent studies have demonstrated that centenarians have a preserved glucose tolerance and insulin action and a more favorable body composition and fat distribution than aged subjects. The strong relationship among glucose tolerance, insulin action, plasma lipid concentration, and lipoprotein metabolism would lead to the hypothesis that healthy centenarians may also have a less atherogenic profile than aged subjects less than 100 years old.

DESIGN

Investigation of the relationship between insulin action and lipid metabolism in healthy centenarians.

PARTICIPANTS

Fifty-six subjects were categorized into three groups: Adults (< or = 50 years old; n = 20); Aged (> or = 75 years old; n = 22); Centenarians (> or = 100 years old; n = 14). The latter represented a select group of individuals free of major age-related diseases.

MEASUREMENTS

Anthropometric measurements were made in all subjects, fasting blood samples were drawn for metabolite determinations, and an euglycemic glucose clamp was performed.

RESULTS

Compared with aged subjects, healthy centenarians appeared to have a less atherogenic plasma lipid profile. Fasting plasma LDL cholesterol (2.4 +/- 0.6 vs 3.7 +/- .6 mmol/L P < .010) was significantly higher in aged subjects than in centenarians, whereas fasting plasma HDL cholesterol (1.0 +/- 0.4 vs 1.7 +/- .4 mmol/L P < .005) had an opposite trend. In centenarians, insulin-mediated glucose uptake was greater (34.6 +/- 0.5 vs 23.3 +/- .05 mumol/Kg FFM x min P < .010) than in aged subjects and correlated with fasting plasma triglycerides, FFA, LDL, and HDL cholesterol, Apo B, and Apo A1 concentrations. Finally, insulin infusion suppressed plasma FFA concentration in similar ways in adults and centenarians.

CONCLUSION

Our study demonstrates that centenarians have a less atherogenic plasma lipid and lipoprotein profile than aged subjects.

Insulin resistance and advancing age: what role for dehydroepiandrosterone sulfate?

The relationship between insulin resistance and aging is still debated. This study aims to investigate the role that age-related differences in plasma dehydroepiandrosterone sulfate (DHEAS) concentration may have on insulin action. For this reason, 75 subjects (42 men and 33 women) with a wide age range (21 to 106 years) were studied. In all subjects, plasma DHEAS and total testosterone concentrations were measured and a euglycemic clamp was used, but substrate oxidation was not determined in centenarians (n = 15). Plasma DHEAS correlated with age (r = -.77, P < .001) and whole-body glucose disposal (WBGD) (r = .57, P < .001). After controlling for age, sex, body fat, and waist to hip ratio (WHR), the association between plasma DHEAS and WBGD was still observed (r = .31, P < .005). Comparing subjects at the third tertile versus those at the first and second tertiles of plasma age-adjusted DHEAS concentration, the former group showed a weaker association between WBGD and age (r = -.38, P < .05) than the latter group (r = -.43, P < .002). The difference between the two regression lines was also significant (P < .03). After controlling for sex, body fat, and WHR, the association between plasma DHEAS and WBGD was dependent on the age of the subjects, being strong in adults (n = 30, age < 50 years, r = .69, P < .001), weak in old subjects (n = 30, age 51 to 99 years, r = .23, P < .05), and absent in centenarians (r = -.05, P < .88). With the subjects divided by sex throughout the different age groups, the univariate association between plasma DHEAS and WBGD was present in females (r = .43, P < .01) but not in males (r = .17, P < .32). Plasma total testosterone and insulin-like growth factor-1 (IGF-1) concentrations declined with advancing age and were significantly correlated with DHEAS and WBGD. In a multivariate analysis with WBGD as the dependent variable, a model including age, sex, body fat, WHR, DHEAS, total testosterone, and IGF-1 explained 66% of WBGD variability, with DHEAS significantly and independently associated with WBGD (P < .004). In conclusion, the negative relationship between advancing age and insulin action seems related to plasma DHEAS concentration. Differences in plasma total testosterone and IGF-1 concentrations may provide a further contribution to the relationship between DHEAS and WBGD.

Association of fasting plasma free fatty acid concentration and frequency of ventricular premature complexes in nonischemic non-insulin-dependent diabetic patients

We investigated the association between free fatty acid (FFA) concentration and ventricular premature complexes (VPCs) in nonischemic patients with non-insulin-dependent diabetes mellitus using 3 approaches: cross-sectional analysis (n = 142), intervention including induction of elevated FFA levels with Intralipid heparin (n = 15), and reduction in FFA levels with Acipimox (n = 34) and a longitudinal follow-up study (n = 59). Patients at the third tertile of fasting plasma FFA concentration had the strongest increase in VPCs. Independently of age, sex, body mass index (BMI), waist/hip ratio, left ventricular mass index, glycated hemoglobin, fasting plasma insulin and triglyceride concentration, and daily physical activity, FFA concentration and VPCs were significantly correlated (r = 0.21 p <0.01). At multiple logistic regression analysis independently of age, sex, BMI, waist/hip ratio, left ventricular mass index, mean arterial blood pressure, glycated hemoglobin, fasting plasma insulin, triglycerides and potassium concentration, fasting plasma low-density lipoprotein/high-density lipoprotein cholesterol ratio, and daily physical activity, plasma FFA concentration was a significant determinant of VPCs (odds ratio 1.2, 95% confidence interval 1.0 to 2.3). Intralipid infusion (10% in 24 hours) (n = 15) and acipimox administration (250 mg, 4 times/day) (n = 34) increased, and decreased fasting plasma FFA concentration, respectively. In those studies, change in VPCs paralleled the effects on plasma FFA. In the longitudinal study (n = 59), plasma FFA concentration predicted the development of VPCs (RR 1.4 95% confidence interval 1.0 to 1.9) independently of age, sex, BMI, waist/hip ratio, left ventricular mass index, mean arterial blood pressure, fasting plasma triglyceride concentration, fasting plasma low-density lipoprotein/high-density lipoprotein cholesterol ratio, and daily physical activity. In conclusion, in nonischemic patients with non-insulin-dependent diabetes mellitus, plasma FFA concentration is associated with the frequency of ventricular premature complexes.

Action palatal tremor in a patient with primary intestinal lymphoma

We report the case of a 59-year-old man with primary intestinal T-cell non-Hodgkin's lymphoma who developed abnormal facial twitching synchronous with small palatal movements induced by attempts at speaking or swallowing. At rest, the electromyogram (EMG) showed no spontaneous muscular activity. Phonation triggered trains of synchronous, rhythmic EMG bursts at a frequency of 3-4 Hz lasting 10-20 s, with an average burst of 150 ms, which simultaneously involved palatal, facial, and neck muscles bilaterally with left-sided predominance. An enhanced blink reflex recovery curve was observed after stimulation of either side. Backaveraging electroencephalographic study revealed no activity that was time locked with the jerks. Axial T2-weighted magnetic resonance imaging showed an increased signal intensity and bilateral enlargement of the inferior olives. No antineuronal-specific antibodies were found in the blood or in the cerebrospinal fluid. All of these clinical findings were consistent with a symptomatic palatal tremor (PT). Because it was triggered by activation of cranial muscles, we termed this movement disorder action PT. To our knowledge, this is the first report of symptomatic PT displaying these features.

Glucose ingestion affects cardiac ANS in healthy subjects with different amounts of body fat

Low-to-high frequency ratio (LF/HF) is an indirect index of sympathovagal balance derived by heart rate spectral analysis. We investigated the effect of glucose ingestion on LF/HF in 17 healthy, normotensive young subjects (9 male, 8 female) with a wide body fat content range (body fat = 29 +/- 5.9%; range = 19-42%) and a normal thyroid hormone status. Before and after an oral glucose tolerance test (OGTT), the Holter technique and indirect calorimetry allowed us to determine heart rate and substrate oxidation in all subjects. At baseline, LF/HF correlated with body fat (r = 0.60, P < 0.005), waist-to-hip ratio (r = 0.57, P < 0.01), fasting plasma insulin (r = 0.55, P < 0.04), leptin (r = 0.56, P < 0.01), and norepinephrine (r = 0.58, P < 0.009) concentrations. Age-, body fat-, content-, and fat-free mass-adjusted respiratory quotient (r = 0.59, P < 0.007) and basal metabolic rate (r = 0.61, P < 0.001) were also correlated with basal LF/HF. Along with OGTT plasma glucose, insulin and norepinephrine concentrations and basal LF/HF significantly rose at 60 min and then declined throughout the test. Area under the curve (AUC) for LF/HF correlated with body fat (r = -0.66, P < 0.004), fasting plasma leptin concentration (r = -0.57, P < 0.01), glucose induced thermogenesis (r = 0.62, P < 0.001), glucose uptake (r = 0.59, P < 0.007), and AUC for plasma norepinephrine concentration (r = 0.63, P < 0.001). Water instead of glucose ingestion does not significantly affect LF/HF (n = 8). In conclusion, our study supports the hypothesis that glucose ingestion affects LF/HF and that such change is related to the amount of body fat.

Spontaneous remission of childhood epilepsy in two patients with focal extraopercular cortical dysplasia

Childhood-onset partial epilepsy caused by focal cortical dysplastic lesions (FCDLs) is often severe. A few patients reported with a favorable outcome had a normal neuropsychological examination, and FCDLs were always localized around the opercular region, suggesting that extent and location of the lesion may account for the favorable outcome. We report two patients with extraopercular FCDLs, who had a spontaneous remission of their childhood-onset epilepsy, despite a severe neurological deficit. A 22-year-old girl (patient 1) and a 16-year-old boy (patient 2), began to have partial seizures at the age of 9 years and 1 year respectively. On neurological examination, patient 1 had left hemiparesis and patient 2 had low IQ. Interictal EEG recordings revealed repetitive epileptiform discharges involving the right temporo-parietal or frontal areas in patients 1 and 2 respectively. MRI study showed focal cortical thickening or abnormal gyration located over the right parietal and frontal region respectively in patients 1 and 2, but failed to evidence T2 prolongation in the white matter beneath the dysplastic cortex. Optimal antiepileptic regimen always stopped seizures. Their long-term course was favorable, with remission of the seizures and normalization of EEG recordings, even 4-5 years after medication withdrawal. In conclusion, FCDLs may cause epilepsy with a benign course even in patient with mental retardation or neurological abnormalities. This may be related to a morphologically milder dysplastic lesion than found in patients with FCDLs and severe epilepsy.

Disappearance of periodic sharp wave complexes in Creutzfeldt-Jakob disease

Periodic sharp wave complexes (PSWC) are sensitive and specific of Creutzfeldt-Jakob disease (CJD). Once they have emerged, PSWC may exceptionally disappear in the terminal stage of the disease, as a consequence of the flattening of scalp electroencephalogram (EEG). We document the disappearance of PSWC in serial EEG during the clinical course in two women (57 and 70 years of age) with pathologically proven CJD. Despite PSWC disappearance, diffuse theta-delta activity was still well recognizable. Moreover, external stimuli failed to trigger PSWC. The absence of PSWC in CJD might be due to the timing and frequency of EEG recordings. PSWC disappearance should not be interpretated as evidence against the diagnosis of CJD.