A 16-week randomized controlled trial of a fish oil and whey protein-derived supplement to improve physical performance in older adults losing autonomy-A pilot study

Background

Low functional capacity may lead to the loss of independence and institutionalization of older adults. A nutritional intervention within a rehabilitation program may attenuate loss of muscle function in this understudied population.

Objective

This pilot study assessed the feasibility for a larger RCT of a nutritional supplementation in older adults referred to an outpatient assessment and rehabilitation program.

Methods

Participants were randomized to receive a supplement (EXP: 2g fish oil with 1500 IU vitamin D3 1x/d + 20-30g whey protein powder with 3g leucine 2x/d) or isocaloric placebo (CTR: corn oil + maltodextrin powder) for 16 weeks. Handgrip and knee extension strength (using dynamometry), physical performance tests and plasma phospholipid n-3 fatty acids (using GCMS) were evaluated at weeks 0, 8 and 16; and lean soft tissue mass (using DXA), at weeks 0 and 16.

Results

Over 2 years, 244 patients were screened, 46 were eligible (18.9%), 20 were randomized, 10 completed the study (6 CTR, 4 EXP). Median age was 87 y (77–94 y; 75% women) and gait speed was 0.69 m/s; 55% had low strength, and all performed under 420m on the 6-minute walk test, at baseline. Overall self-reported compliance to powder and oil was high (96% and 85%) but declined at 16 weeks for fish oil (55%). The EXP median protein intake surpassed the target 1.2–1.5 g/kg/d, without altering usual diet. Proportions of plasma phospholipid EPA and DHA increased significantly 3- and 1.5-fold respectively, at week 8 in EXP, with no change in CTR. Participants were able to complete most assessments with sustained guidance.

Conclusion

Because of low eligibility, the pilot study was interrupted and deemed non-feasible; adherence to rigorous study assessments and to supplements was adequate except for long-term fish oil. The non-amended protocol may be applied to populations with greater functional capacity.

Trial registration

ClinicalTrials.gov NCT04454359.

Acute hyperaminoacidemia does not suppress insulin-mediated glucose turnover in healthy young men

Elevated circulating amino acids (AA) concentrations are purported to cause insulin resistance (IR) in humans. To quantify hyperaminoacidemia effects on insulin-mediated glucose turnover in healthy men, we performed 2-stage pancreatic clamps using octreotide with glucagon and growth hormone replacement. In the basal stage, insulin was infused to maintain euglycemia at postabsorptive levels. During the clamp stage, insulin was raised to postprandial levels, glycemia clamped at 5.5 mmol/L by glucose infusion, and branched-chain AA (BCAA) maintained at either postabsorptive (Hyper1; n = 8) or postprandial (Hyper2; n = 7) by AA infusion. Glucose turnover was measured by d-3-[³H]glucose dilution. Octreotide suppressed C-peptide; glucagon, growth hormone, and glycemia were maintained at postabsorptive levels throughout. Insulin did not differ at postabsorptive (72 ± 5 vs. 60 ± 5 pmol/L; Hyper1 vs. Hyper2) and increased to similar concentrations at basal (108 ± 11 vs. 106 ± 14) and clamp stages (551 ± 23 vs. 540 ± 25). Postabsorptive BCAA were maintained during Hyper1 and increased >2-fold (830 ± 26 µmol/L) during Hyper2. Endogenous glucose production was similarly suppressed (0.95 ± 0.16 vs. 1.37 ± 0.23 mg/kg lean body mass/min; Hyper1 vs. Hyper2) and basal glucose disposal (3.44 ± 0.12 vs. 3.67 ± 0.14) increased to similar levels (10.89 ± 0.56 vs. 11.11 ± 1.00) during the clamp. Thus, acute physiological elevation of AA for 3 h did not cause IR in healthy men. Novelty: A 2-step pancreatic clamp was used to quantify the effect of AA on insulin sensitivity in humans. Acute physiological elevation of circulating AA to postprandial levels does not cause IR in healthy men.

A 16-week Randomized Controlled Trial of a Fish Oil and Whey Protein-Derived Supplement to Improve Physical Performance in Older Adults Losing Autonomy – A Pilot Study

Objectives

Loss of autonomy is often the trigger for institutionalization of older adults. A nutritional intervention within a rehabilitation program may attenuate loss of muscle mass and function to enable continued autonomy in this understudied group of seniors. Objectives: 1) To assess the feasibility of a combined nutrient supplementation intervention with regards to recruitment, compliance, and completion of assessments in older adults losing autonomy; 2) to characterize this specific population.

Methods

Seniors taking part in a rehabilitation program were randomized to an intervention with a supplement (EXP: 2 g fish oil (EPA+ DHA) with 1500 IU vitamin D3 1x/d+ 20–30 g whey protein powder with 3 g leucine 2x/d) or placebo (CTR; corn oil and maltodextrin powder) for 16 weeks. Lean soft tissue mass (LM) and physical function were assessed. LM (DXA) was measured at weeks 0 and 16, handgrip and knee extension strength (dynamometry), physical performance tests and plasma phospholipid n-3 fatty acids (GCMS) were evaluated at weeks 0, 8 and 16.

Results

Over 2 y, 244 patients were screened, 46 were eligible (18.9%; 95% CI: 15.0, 22.8), 20 were randomized, 10 completed the study (n = 4 in EXP; n = 6 in CTR). Median age was 87 y (77–94 y; 75% women), 35% had low LM, 35% were frail, 85% were using a walking aid daily and physical performance was low, at baseline. Overall self-reported compliance to powder was 96% (95% CI: 83, 108) and to oil, 85% (95% CI: 63, 107). The EXP median protein intake alone surpassed the target 1.2–1.5 g/kg/d for older adults, without altering usual diet. Proportions of EPA and DHA increased significantly 3- and 1.5-fold respectively at week 8 in EXP, with no change in CTR. Participants were able to complete most assessments with sustained guidance.

Conclusions

Because of low eligibility limiting the pool of potential patients, the pilot study was interrupted as deemed non-feasible; however, compliance to supplements and the rigorous study assessments was high. Solutions to address recruitment, such as more liberal eligibility criteria, need to be considered in the design of a large-scale RCT before it can be carried out in this challenging population.

Funding Sources

Helen McCall Hutchison Award and Réseau québécois de la recherche sur le vieillissement of FRQS.

Leucine Supplementation Does Not Alter Insulin Sensitivity in Prefrail and Frail Older Women following a Resistance Training Protocol

BACKGROUND

Frailty is a clinical condition associated with loss of muscle mass and strength (sarcopenia). Although sarcopenia has multifactorial causes, it might be partly attributed to a blunted response to anabolic stimuli. Leucine acutely increases muscle protein synthesis, and resistance training (RT) is the strongest stimuli to counteract sarcopenia and was recently shown to improve insulin sensitivity (IS) in frail older women. Discrepancies exist regarding whether chronic supplementation of leucine in conjunction with RT can improve muscle mass and IS.

OBJECTIVE

The aim of this double-blinded placebo-controlled study was to determine the effects of leucine supplementation and RT on IS in prefrail and frail older women.

METHODS

Using the Fried criteria, 19 nondiabetic prefrail (1-2 criteria) and frail (≥3 criteria) older women (77.5 ± 1.3 y; body mass index (kg/m2): 25.1 ± 0.9) underwent a 3-mo intervention of RT 3 times/wk with protein-optimized diet of 1.2 g·kg-1·d-1 and 7.5 g·d-1 of l-leucine supplementation compared with placebo l-alanine. Pre-/postintervention primary outcomes were fasting plasma glucose, serum insulin, and 4-h responses to a standard meal of complete liquid formula. Secondary outcomes of resting energy expenditure using indirect calorimetry and body composition using dual-energy X-ray absorptiometry were obtained. Paired t tests analyzed pooled data, and 2-factor repeated-measures ANOVA determined supplementation, training, and interaction effects.

RESULTS

No significant time, group, or interaction effects were observed for postprandial areas under the curve of serum insulin or plasma glucose or for resting energy expenditure in l-leucine compared with l-alanine. Total lean body mass increased and percentage body fat decreased significantly for both groups postintervention (0.76 ± 0.13 and -0.92 ± 0.33 kg, respectively; time effect: P < 0.01).

CONCLUSIONS

IS was not affected by RT and leucine supplementation in nondiabetic prefrail and frail older women. Therefore, leucine supplementation does not appear to influence IS under these conditions. This trial was registered at clinicaltrials.gov as NCT01922167.

Neurocognitive and Hormonal Correlates of Voluntary Weight Loss in Humans

Insufficient responses to hypocaloric diets have been attributed to hormonal adaptations that override self-control of food intake. We tested this hypothesis by measuring circulating energy-balance hormones and brain functional magnetic resonance imaging reactivity to food cues in 24 overweight/obese participants before, and 1 and 3 months after starting a calorie restriction diet. Increased activity and functional connectivity in prefrontal regions at month 1 correlated with weight loss at months 1 and 3. Weight loss was also correlated with increased plasma ghrelin and decreased leptin, and these changes were associated with food cue reactivity in reward-related brain regions. However, the reduction in leptin did not counteract weight loss; indeed, it was correlated with further weight loss at month 3. Activation in prefrontal regions associated with self-control could contribute to successful weight loss and maintenance. This work supports the role of higher-level cognitive brain function in body-weight regulation in humans.

Academic stress and personality interact to increase the neural response to high-calorie food cues

Psychosocial stress is associated with an increased intake of palatable foods and weight gain in stress-reactive individuals. Personality traits have been shown to predict stress-reactivity. However, it is not known if personality traits influence brain activity in regions implicated in appetite control during psychosocial stress. The current study assessed whether Gray's Behavioural Inhibition System (BIS) scale, a measure of stress-reactivity, was related to the activity of brain regions implicated in appetite control during a stressful period. Twenty-two undergraduate students participated in a functional magnetic resonance imaging (fMRI) experiment once during a non-exam period and once during final exams in a counter-balanced order. In the scanner, they viewed food and scenery pictures. In the exam compared with the non-exam condition, BIS scores related to increased perceived stress and correlated with increased blood-oxygen-level dependent (BOLD) response to high-calorie food images in regions implicated in food reward and subjective value, such as the ventromedial prefrontal cortex, (vmPFC) and the amygdala. BIS scores negatively related to the functional connectivity between the vmPFC and the dorsolateral prefrontal cortex. The results demonstrate that the BIS trait influences stress reactivity. This is observed both as an increased activity in brain regions implicated in computing the value of food cues and decreased connectivity of these regions to prefrontal regions implicated in self-control. This suggests that the effects of real life stress on appetitive brain function and self-control is modulated by a personality trait. This may help to explain why stressful periods can lead to overeating in vulnerable individuals.

Insulin resistance of protein anabolism accompanies that of glucose metabolism in lean, glucose-tolerant offspring of persons with type 2 diabetes

OBJECTIVE

To test whether protein anabolic resistance is an early defect in type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

Seven lean, normoglycemic T2D offspring (T2D-O) and eight matched participants without family history (controls; C) underwent a 3-hour hyperinsulinemic (40 mU/m²/min), euglycemic (5.5 mmol/L) and isoaminoacidemic clamp. Whole-body glucose and protein kinetics were measured with d-[3-³H]glucose and l-[l-¹³C]leucine, respectively. Plasma amino acids were measured by liquid chromatography-tandem mass spectrometry.

RESULTS

Fasting glycemia and glucose kinetic variables did not differ between groups. Clamp decreases in glucose rate of appearance were not different, but rate of disappearance increased 29% less in T2D-O, to a significantly lower rate. Fasting leucine was higher in T2D-O, but kinetics did not differ. Clamp increases in leucine oxidation and decreases in endogenous rate of appearance (protein breakdown) were equal, but in T2D-O, non-oxidative rate of disappearance (protein synthesis) did not increase and net balance (synthesis-breakdown) did not become positive as in C.

CONCLUSIONS

Resistance of whole-body protein anabolism (synthesis and net balance) accompanies resistance of glucose uptake in T2D-O. Mechanisms responsible, possible roles in the increased risk of developing diabetes, and its potential impact on long-term protein balance require definition.

Adiponectin-SOGA Dissociation in Type 1 Diabetes

CONTEXT

Circulating adiponectin is elevated in human type 1 diabetes (T1D) and nonobese diabetic (NOD) mice without the expected indications of adiponectin action, consistent with tissue resistance.

OBJECTIVE

Adiponectin stimulates hepatocyte production of the suppressor of glucose from autophagy (SOGA), a protein that inhibits glucose production. We postulated that due to tissue resistance, the elevation of adiponectin in T1D should fail to increase the levels of a surrogate marker for liver SOGA, the circulating C-terminal SOGA fragment.

MAIN OUTCOME MEASURES

Liver and plasma SOGA were measured in NOD mice (n = 12) by Western blot. Serum adiponectin and SOGA were measured in T1D and control (Ctrl) participants undergoing a three-stage insulin clamp for the Coronary Artery Calcification in T1D study (n = 20). Glucose turnover was measured using 6,6[(2)H2]glucose (n = 12).

RESULTS

In diabetic NOD mice, the 13%-29% decrease of liver SOGA (P = .003) and the 30%-37% reduction of circulating SOGA (P < .001) were correlated (r = 0.826; P = .001). In T1D serum, adiponectin was 50%-60% higher than Ctrl, SOGA was 30%-50% lower and insulin was 3-fold higher (P < .05). At the low insulin infusion rate (4 mU/m(2)·min), the resulting glucose appearance correlated negatively with adiponectin in T1D (r = -0.985, P = .002) and SOGA in Ctrl and T1D (r = -0.837, P = .001). Glucose disappearance correlated with adiponectin in Ctrl (r = -0.757, P = .049) and SOGA in Ctrl and T1D (r = -0.709, P = .010). At 40 mU/m(2)·min, the lowered glucose appearance was similar in Ctrl and T1D. Glucose disappearance increased only in Ctrl (P = .005), requiring greater glucose infusion to maintain euglycemia (8.58 ± 1.29 vs 3.09 ± 0.87 mg/kg·min; P = .009).

CONCLUSIONS

The correlation between liver and plasma SOGA in NOD mice supports the use of the latter as surrogate marker for liver concentration. Reduced SOGA in diabetic NOD mice suggests resistance to adiponectin. The dissociation between adiponectin and SOGA in T1D raises the possibility that restoring adiponectin signaling and SOGA might improve the metabolic response to insulin therapy.

Protein and glucose metabolic responses to hyperinsulinemia, hyperglycemia, and hyperaminoacidemia in obese men

OBJECTIVE

In insulin-resistant states, resistance of protein anabolism occurs concurrently with that of glucose, but can be compensated for by abundant amino acid (AA) provision. This effect and its mechanism were sought in obesity.

METHODS

Pancreatic clamps were performed in 8 lean and 11 obese men, following 5-h postabsorptive, 3-h infusions of octreotide, basal glucagon, and growth hormone, with clamped postprandial-level insulin, glucose, and AA. Whole-body [1-(13) C]-leucine and [3-(3) H]-glucose kinetics, skeletal muscle protein ((2) H5 -phenylalanine) fractional synthesis rates, and insulin signaling were determined.

RESULTS

Clamp Δ insulin and Δ branched-chain AA did not differ; fasting glucagon and growth hormone were maintained. Glucose uptake was 20% less in obese concurrent with less Akt(Ser473) , but also less IRS-1(Ser636/639) phosphorylation. Stimulation of whole-body, myofibrillar, and sarcoplasmic protein synthesis was similar. Whole-body protein catabolism suppression tended to be less (P=0.06), resulting in lesser net balance (1.09 ± 0.07 vs. 1.31 ± 0.08 μmol [kg FFM(-1) ] min(-1) , P=0.048). Increments in muscle S6K1(Thr389) phosphorylation were less in the obese, but 4E-BP1(Ser65) did not differ.

CONCLUSIONS

Hyperaminoacidemia with hyperinsulinemia stimulated protein synthesis (possibly via nutrient signaling) normally in obesity, but suppression of proteolysis may be compromised. Whether long-term high protein intakes could compensate for the insulin resistance of protein anabolism remains to be determined.

Increase in the Thermic Effect of Food in Women by Adrenergic Amines Extracted from Citrus Aurantium

OBJECTIVE

To compare the thermic response to a meal between men and women of varied body composition and to determine whether adrenergic amines extracted from citrus aurantium (CA) induce an increase in metabolic rate and enhance the thermic response to the meal.

RESEARCH METHODS AND PROCEDURES

In 30 healthy weight-stable subjects (17 women, 13 men; BMI: 20 to 42 kg/m2), body composition was determined by bioimpedance analysis followed by resting energy expenditure for 20 minutes, and the thermic effect of food (TEF) of a 1.7-MJ, 30-gram protein meal was determined intermittently for 300 minutes by indirect calorimetry. In a subset of 22 subjects, the TEFs of CA alone and when added to the same 1.7-MJ meal were determined. Blood pressure and pulse before and throughout the studies and catecholamine excretion were determined.

RESULTS

TEF was significantly lower in women than men (152 +/- 7 vs. 190 +/- 12 kJ and 8.8 +/- 0.4% vs. 11.0 +/- 0.7% of meal), independently of age and magnitude of adiposity. The thermic response to CA alone was higher in men, but, when added to the meal, CA increased TEF only in women and to values no longer different from men. CA had no effect on blood pressure and pulse rate but increased epinephrine excretion by 2.4-fold.

DISCUSSION

A 20% lower TEF in women suggests a diminished sympathetic nervous system response to meals, because with CA, TEF increased by 29% only in women. However, this acute response may not translate into a chronic effect or a clinically significant weight loss over time.

Antihyperglycaemic medication modifies factors of postprandial satiety in type 2 diabetes

AIM

Type 2 diabetes is characterized by hyperglycaemia, delayed gastric emptying and a blunted response of gut hormones during feeding that may modulate satiety. We hypothesized that it is associated with more hunger when treated by medication.

METHODS

We studied nine type 2 diabetic men (A1C: 6.7+/-0.3%, waist circumference: 104+/-4 cm) after an overnight fast, during 5 h in response to a 2.88 MJ breakfast, twice, in a crossover design, with or without antihyperglycaemic agents. Satiety ratings, thermic effect of meal, gastric emptying, plasma concentrations of gut peptides, leptin, insulin and substrates and intake from a subsequent buffet were determined.

RESULTS

With medication, fasting and postprandial plasma glucose levels were lower but area under the curve (AUC) did not vary vs. without medication. Gastric emptying was shortened, branched chain amino acids (BCAA) AUC and thermic effect were lower, and postprandial glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine (PYY3-36) were maintained at higher levels beyond 4 h. Correlations were significant between duration of diabetes and fasting ghrelin (r=0.779, p=0.013) and peak insulin (r=-0.769, p=0.016), 5-h postmeal ghrelin and peak glucose (r=0.822, p=0.007), 5-h glucose and GLP-1 (r=-0.788, p=0.012), and 5-h hunger scores and energy intake at buffet (r=0.828, p=0.006). Without medication, fullness scores correlated with BCAA levels. Visual analogue scale scores, ghrelin and leptin levels did not differ between studies.

CONCLUSIONS

The decrease in factors associated with postprandial satiety with treatment is counterbalanced by higher GLP-1 and PYY3-36. Medication may normalize the link between perception of hunger and subsequent food intake.

Determinants of whole-body protein metabolism in subjects with and without type 2 diabetes

OBJECTIVE

Whole-body protein metabolism is abnormal in suboptimally controlled type 2 diabetes and obesity. We hypothesized that glycemia, insulin resistance, and waist circumference modulate these alterations in type 2 diabetes and, to a lesser extent, in individuals without type 2 diabetes.

RESEARCH DESIGN AND METHODS

In 88 lean and obese subjects without and 40 with type 2 diabetes on an inpatient protein-controlled isoenergetic diet for 7 days, whole-body protein turnover was measured using the fed-fasted 60-h oral (15)N-glycine method. Nitrogen flux was determined from urinary (15)N urea and protein synthesis, breakdown and net balance calculated. Indexes of diabetes control, resting energy expenditure (REE), and body composition were assessed.

RESULTS

Higher protein turnover in obese subjects was further increased, and net balance was lower in type 2 diabetes. Waist-to-hip ratio and ln homeostasis model assessment of insulin resistance (HOMA-IR) explained 40% of the variance in flux in type 2 diabetes; fat-free mass and lnHOMA-IR explained 62% in subjects without type 2 diabetes. Overall, fasting glucose explained 16% of the variance in net balance. In type 2 diabetes, net balance correlated negatively with fasting glucose in men and positively with hip circumference in women.

CONCLUSIONS

Kinetics of whole-body protein metabolism are elevated, and net balance is diminished in type 2 diabetes, independently of obesity. Elevated flux is associated with greater visceral adiposity, REE, and insulin resistance of glucose. In type 2 diabetic men, these alterations worsened with magnitude of hyperglycemia. In type 2 diabetic women, larger hip circumferences may protect against such alterations. Our findings suggest that dietary protein requirements may be greater in type 2 diabetes to offset a reduced net balance, aggravated as glycemia increases, especially in men.

Malignant transformation of a solitary fibrous tumor of the liver and intractable hypoglycemia

Sarcomas of the liver are rare. We report a case of intractable hypoglycemia secondary to a solitary fibrous tumor that underwent malignant transformation into a fibrosarcoma. A 70-year-old man presented with a hepatic mass and tumor-associated hypoglycemia which was resistant to medical management. Blood tests were remarkable only for elevated serum insulin-like growth factor (IGF)-2. The hypoglycemia resolved following resection of a solitary fibrous tumor surrounded by a high-grade fibrosarcoma. Real time reverse transcriptase polymerase chain reaction (RT-PCR) measured elevated levels of IGF2 mRNA in both the solitary fibrous tumor and the fibrosarcoma. Immunoblotting demonstrated a series of bands in the size range of pro-IGF2. Unfortunately, disseminated metastases developed 1 year later, concurrent with a recurrence of hypoglycemia, marked again by elevation of serum IGF2. Solitary fibrous tumors of the liver have a real risk of malignant transformation. The severity of the tumor-associated hypoglycemia may parallel the tumor burden and activity. The syndrome is the systemic effect of IGF2 secreted by the tumor. Surgery can treat the hypoglycemia syndrome and the underlying malignancy.

Influence of Adiposity in the Blunted Whole-Body Protein Anabolic Response to Insulin With Aging

BACKGROUND

Although insulin resistance of glucose is often reported with aging, that of protein metabolism is still debated. We tested if the insulin sensitivity of protein metabolism parallels that of glucose and is altered with aging.

METHODS

Whole-body (13)C-leucine and (3)H-glucose kinetics were measured in the postabsorptive state and during an hyperinsulinemic, euglycemic, isoaminoacidemic clamp in 12 young men (age: 27 +/- 1 years; body mass index [BMI]: 23 +/- 1 kg/m(2)), 11 young women (age: 25 +/- 1 years; BMI: 21 +/- 1 kg/m(2)), 9 elderly men (age: 70 +/- 1 years; BMI: 26 +/- 1 kg/m(2)), and 10 elderly women (age: 69 +/- 2 years; BMI: 23 +/- 1 kg/m(2)).

RESULTS

Postabsorptive leucine flux rates adjusted for fat-free mass (FFM) were not different between elderly and young participants. During the clamp, leucine flux and protein synthesis rates increased less in the elderly participants, and protein breakdown decreased equally. Thus, the net anabolic (protein balance) response to hyperinsulinemia was lower in elderly versus young participants (p =.007) and was highly correlated with the clamp glucose rate of disposal (r = 0.671, p <.001), indicating insulin resistance of protein concurrent with that of glucose. From regression analysis, FFM explained 73% of the variance in the anabolic response. Age explained an additional 3%, but was accounted for by markers of adiposity. FFM and percent body fat collectively explained 79% of the variance.

CONCLUSION

Both reduction in absolute FFM and increased adiposity, intrinsic to the aging process, are associated with an altered anabolic action of insulin in stimulating protein synthesis. This alteration may contribute to the progressive muscle loss with aging.

Elevations of plasma methylarginines in obesity and ageing are related to insulin sensitivity and rates of protein turnover

AIMS/HYPOTHESIS

Increased circulating methylarginines (MA) have been linked to the metabolic syndrome to explain endothelial dysfunction and cardiovascular disease risk. Proteins that contain MA are regulatory and release them during catabolism. We hypothesised that increased protein turnover in insulin-resistant states contributes to an increase in circulating MA. MATWERIALS AND METHODS: We performed hyperinsulinaemic, euglycaemic, and isoaminoacidaemic experiments on 49 lean, obese and elderly subjects, with measurements of the kinetics of glucose and protein metabolism. Plasma MA, i.e. asymmetrical dimethylarginine (ADMA), symmetrical dimethylarginine (SDMA), and N -monomethyl-L-arginine (NMMA), lipids and body composition were measured.

RESULTS

Insulin resistance of glucose and protein metabolism occurred in obese and elderly subjects. ADMA concentrations were 29 to 120% higher in obese and 34% higher in elderly than in lean subjects. SDMA were 34 and 20% higher in obese than in lean and than in elderly subjects, respectively. NMMA were 32% higher in obese than in lean subjects. ADMA differed by sex, being higher in men, namely by 1.75x in obese men and by 1.27x in elderly men. Postabsorptive ADMA (r=0.71), SDMA (r=0.46), and NMMA (r=0.31) correlated (all p<0.05) with rates of protein flux. All three MA correlated negatively with clamp glucose infusion rates and uptake (p<0.001). ADMA and SDMA correlated negatively with net protein synthesis and clamp amino acid infusion rates (p<0.05). All MA also correlated with adiposity indices and fasting insulin and triglycerides (p<0.05).

CONCLUSIONS/INTERPRETATION

Obesity, sex and ageing affect MA. Elevations of the three MA in obese, and of ADMA in elderly men, are related to increased protein turnover and to lesser insulin sensitivity of protein metabolism. These interrelationships might amplify insulin resistance and endothelial dysfunction.

The influence of sex on the protein anabolic response to insulin

We hypothesize that sex influences whole-body protein anabolism in the postabsorptive state and in response to hyperinsulinemia. Kinetics of 3-(3)H-glucose and (13)C-leucine were studied in 16 men and 15 women after energy- and protein-controlled diets, before and during a hyperinsulinemic, euglycemic, isoaminoacidemic clamp. In the postabsorptive state, women had 20% higher rates of leucine Ra (protein breakdown) and nonoxidative Rd (synthesis) adjusted for fat-free mass than men but net leucine balance was as negative. In response to hyperinsulinemia, leucine oxidation rates increased only in women and the change in net leucine balance was less than in men. Net leucine balance during the clamp correlated with rates of glucose disposal. Thus, women showed greater protein turnover rates when adjusted for fat free mass in the postabsorptive state, and lesser insulin sensitivity of protein anabolism and net protein accretion. A relationship exists between the protein anabolic response to insulin and the insulin sensitivity of glucose metabolism.

Whole-body protein anabolic response is resistant to the action of insulin in obese women

BACKGROUND

Obesity is associated with insulin resistance of glucose and lipid metabolism.

OBJECTIVE

We sought to determine the effects of obesity on the insulin sensitivity of protein metabolism.

DESIGN

Whole-body [(13)C]leucine and [(3)H]glucose kinetics were measured in 9 lean and 10 obese women in the postabsorptive state and during a hyperinsulinemic, euglycemic, isoaminoacidemic clamp.

RESULTS

In the postabsorptive state, the leucine endogenous rate of appearance (catabolism), normalized for fat-free mass, was 11% greater and the nonoxidative rate of disappearance (synthesis) was 8% greater in the obese than in the lean women, but net balance was 29% more negative (P < 0.05). Clamp amino acid and glucose infusion rates were significantly lower in the obese women than in the lean women (0.65 +/- 0.02 compared with 0.85 +/- 0.04 and 5.7 +/- 0.3 compared with 9.1 +/- 0.5 mg x kg fat-free mass(-1) x min(-1), respectively; P < 0.0001 for both), and their rates correlated positively (r = 0.635, P = 0.005). During hyperinsulinemia, synthesis was stimulated less and net leucine balance was much lower in the obese women than in the lean women (-0.08 +/- 0.06 and 0.30 +/- 0.03 mumol x kg fat-free mass(-1) x min(-1), respectively; P < 0.0001). The percentage change in net leucine balance correlated negatively with all adiposity indexes. Plasma free fatty acids were less suppressed and the respiratory quotient was lower in the obese women than in the lean women.

CONCLUSION

Obese women show a blunted protein anabolic response to hyperinsulinemia that is consistent with resistance to the action of insulin on protein concurrent with that on glucose and lipid metabolism.

[Phalloidian toxins]

The phalloidian toxins are very complex. The classification proposed by Wieland distinguishes between the various amatoxins and phallotoxins. The authors study successively: Methods of isolation, the general structure and chemical composition, their localization and concentration in mushrooms. This is an analytical study of the phallotoxins and amadoxins. Various experimental intoxication protocols using total extracts of the toxins purified with different doses and different animals have revealed the main signs of experimental intoxication with phallotoxins. This is characterized especially by hepatic and renal lesions. The phallotoxins have a more specific action on the cell membrane and metabolism. The amatoxins have a more specific action on the cell nucleus and protein synthesis. The action on DNA dependent RNA polymerases is particularly characteristic.

The prediction of resting energy expenditure in type 2 diabetes mellitus is improved by factoring for glycemia

BACKGROUND

Predictive equations have been reported to overestimate resting energy expenditure (REE) for obese persons. The presence of hyperglycemia results in elevated REE in obese persons with type 2 diabetes, and its effect on the validity of these equations is unknown.

OBJECTIVE

We tested whether (1) indicators of diabetes control were independent associates of REE in type 2 diabetes and (2) their inclusion would improve predictive equations.

DESIGN

A cross-sectional study of 65 (25 men, 40 women) obese type 2 diabetic subjects. Variables measured were: REE by ventilated-hood indirect calorimetry, body composition by bioimpedance analysis, body circumferences, fasting plasma glucose (FPG) and hemoglobin A(1c). Data were analyzed using stepwise multiple linear regression.

RESULTS

REE, corrected for weight, fat-free mass, age and gender, was significantly greater with FPG>10 mmol/l (P=0.017) and correlated with FPG (P=0.013) and hemoglobin A(1c) as percentage upper limit of normal (P=0.02). Weight was the main determinant of REE. Together with hip circumference and FPG, it explained 81% of the variation. FPG improved the predictability of the equation by >3%. With poor glycemic control, it can represent an increase in REE of up to 8%.

CONCLUSION

Our data indicate that in a population of obese subjects with type 2 diabetes mellitus, REE is better predicted when fasting plasma glucose is included as a variable.

Parieto-temporal rhythms in the 6-9 Hz band recorded in epileptic patients with depth electrodes in a self-paced movement protocol

OBJECTIVES

Description of 6-9 Hz rhythmic electrical activity observed on recordings from electrodes implanted in the cortex of epileptic patients undergoing presurgical evaluation.

METHODS

Recordings were obtained from 74 patients with multilead electrodes in the frontal, parietal and temporal cortex. The motor task consisted of a self-paced fist clenching movement at approximately 10 s intervals. Events within a window extending from 4 s before to 1 s after movement EMG onset were analyzed.

RESULTS

(i) Spindle-like rhythmic activity at 6-9 Hz was observed in 29 patients. (ii) This activity was located in the inferior parietal and superior temporal areas. (iii) Enhancement of rhythmic activity occurred when patients were asked to perform the motor task. (iv) A striking tendency to phase-locking of rhythmic oscillations on consecutive trials was noted during the 3-2 s epoch before movement EMG onset.

CONCLUSION

Whether this intracerebrally recorded 6-9 Hz rhythmic activity belongs to the mu-alpha class or is a special type of theta, and if it is related to the epileptic process or to drug treatment remain open to discussion. Motor-task related enhancement and phase-locking suggest that this activity may be one more indicator of movement preparation.

Steep early negative slopes can be demonstrated in pre-movement bereitschaftspotential

OBJECTIVES

The study presents data suggesting that the classic bereitschaftspotential hides in its early component (BP1) steep increases of negativity which precede the movement at varying intervals in repeated trials.

METHODS

In 12 volunteers, surface EEG from Fz, Cz, C3, C4, and Pz electrodes and EMG from the flexor digitorum communis were recorded during self-paced wrist flexions. Two hundred trials were collected from each subject. The single trials were grouped for averaging in two different ways. In the first one, single trials for each subject were used to create individual averages. In the second, all single trials were divided into groups according to the point in time of small steep negative shift from the baseline detected on sweeps before the movement and time group averages were created. The identification of small shifts was based on the comparison of calculated mean amplitudes in the first and the second half of the 1 s time window moved along the time axis.

RESULTS

The small negative shifts were identified in 97.2% of analyzed records. In each subject, their position on the time axis varied considerably. Individual averages exhibited the characteristics of classical readiness potential, i.e. slow early component, steep late component, laterality over motor cortices. On the other hand, all time group averages (26) displayed an early steep negative shift followed by plateau which, about 0.5 s before the movement, gave rise to the second, late steep negative shift. The slope values calculated in the definite segments of averaged curves were used as a measure of the amplitude of these shifts over various brain areas. MANOVA showed a significant effect of the electrode position both in the case of early slopes (F(4,115)=9.7; P<0.000) and in the case of late slopes (F(4,115)=22.5; P<0.000). In both cases, the largest value was demonstrated under Cz electrode. In contrast to the late slopes, the values of early slopes did not exhibit laterality and suggested greater importance of pre-frontal regions in their formation.

CONCLUSION

We have suggested that the formation of steep early negative shifts from the baseline in time group averages was due to synchronization of a mental process which, under classical averaging procedure, was dispersed uniformly throughout the pre-movement period.

Event-related potentials, CNV, readiness potential, and movement accompanying potential recorded from posterior thalamus in human subjects. A SEEG study

Intracranial recordings were obtained from three patients with intractable chronic pain who underwent analgesic electrical stimulation of the contralateral thalamus. Multilead electrode made it possible to record from several thalamic nuclei. The electrode was targeted into the ventroposterolateral (VPL) nucleus of the thalamus. During separate recording sessions, the following tests were performed: somatosensory evoked potentials (SEP) of the median or posterior tibial nerve, event-related cognitive potentials (auditory oddball P3 wave), readiness potential (RP) and contingent negative variation (CNV) using auditory warning (S1) and visual imperative (S2) stimuli. The movement accompanying potential (MAP), which was present in the VPL in all but one of the recordings, behaved as a far-field potential. Recordings obtained from the VPL confirmed its established role as a relay nucleus, processing somatosensory information to the primary somatosensory cortex. The VPL generated the 'thalamic' SEP, which was the only potential regularly recorded in this nucleus. In the recordings from one patient (No. 3), auditory and visual evoked potentials of the CNV protocol, peaking at approximately 300 ms, were obtained from the VPL and appeared to be generated in situ. Neither RP, CNV nor 'oddball' ERPs appeared in the VPL. From the pulvinar, only a visually evoked potential was recorded. Oddball P3, RP, CNV, and middle and long latency auditory and visual potentials (evoked in the CNV paradigm) appeared to be generated 'dorsally' to the VPL, probably in the nucleus posterolateralis (PL). This structure may therefore be involved in both the processing of afferent information and in cognitive operations.

Synchronizing effect of clock rhythm on the 'when to move' decision in repeated voluntary movements

In 13 volunteers, surface EEGs from F(z), C(z), C(3), C(4), and P(z) electrodes and EMG from the flexor digitorum communis were recorded during an experimental task in which the performance of wrist flexion was linked with the selection of a clock sound. In the epoch from 4 to 1 s before movement, more than 95% of the records exhibited a small negative shift from the baseline. The position of these shifts on the time axis made it possible to create groups of time trials. The average EEG curves from these groups showed one prominent negative shift from the baseline, which could be related to the position of particular clock sounds. The slope values of these shifts were highest under the F(z) and C(z) electrodes. We suggested that these negative shifts coincided with 'when to move' decisions, which preceded the execution of the movement at varying intervals.

Intracerebral recording of potentials accompanying simple limb movements: a SEEG study in epileptic patients

OBJECTIVES

Slow potentials appearing during simple repetitive acral limb movement were investigated. Twenty-six patients suffering from drug resistant partial epilepsies and explored with implanted intracerebral electrodes were examined using two protocols.

METHODS

In 18 patients, readiness potential (RP), in 13 patients contingent negative variation (CNV), and in 7 patients both protocols, were tested. The recordings from leads with evident pathological EEG activity were excluded from evaluation. The results concerning the slow potentials preceding the movements in RP and CNV protocols have already been published.

RESULTS

The movement-accompanying slow potentials (MASP) were polyphasic or monophasic, started before or during the movement. In the primary motor cortex they followed the pre-movement potentials depending on the protocol: in the RP paradigm they were present only contralateral to the movement, but were bilateral in the CNV protocol. In other areas they either followed the potentials preceding the movement, in some cases with opposite polarity, or they occurred alone. MASP was recorded in motor and supplementary motor, premotor and prefrontal, midtemporal, somatosensory, superior parietal and cingular cortices. The cingular cortex was heavily involved in the self-paced movements but rarely in the cued movements.

CONCLUSION

The major involvement of the cingular gyrus contrasted with the absence of slow potentials in temporal limbic structures. MASP is evidently a heterogenic phenomenon. Its genesis could be involved in a spread of information through the relevant structures.

Presence of very early events preceding self-paced movements in epileptic patients. An intracerebral exploration

In epileptic patients explored with depth electrodes kept within the brain for several days ("chronic conditions") to localize their focus, recordings were taken from the less perturbed deep brain areas, before and during the execution of self-paced movements. A few deep leads (some of which were located in areas which did not display a classical readiness potential) showed that phasic paroxystic events very often occurred 2,000 ms and, sometimes, even about 3,000 ms before the movement (movement-related events, MREs). This finding suggests that the preparation of a "voluntary" self-paced movement may begin well before the appearance of the readiness potential or, alternatively, that intracerebral paroxystic spikes delay the decision making. This type of phasic process may be undetectable in scalp recording from normal subjects and only be revealed when some brain structures have become hyper-reactive due to the epileptic process.

The early component of the premovement readiness potential and its behavioral determinants

Fifteen healthy subjects were asked to randomly select a tick of a mechanical clock which was operating throughout the experiment and to flex their wrist at the chosen tick. The individual averages of EEG recordings collected during the period of the putative decision to begin the task exhibited steep slopes of negativity followed by plateaus. These slopes preceded the selection of the signal sound at varying intervals, the longest interval was 3 s. The grand average of individual averages depicted a waveform whose shape was identical to the early component of the classical readiness potential. Another interesting finding came from experiments with mental counting of clock sounds, which demonstrated that the generation of the first mentally-counted number is preceded by a distinct negative potential shift.

Differences in pain medication use in stroke patients with aphasia and without aphasia

BACKGROUND AND PURPOSE

While individuals with stroke are known to experience pain for a variety of reasons including premorbid conditions and stroke-specific sequelae, there are some groups of individuals with stroke, who because of aphasia, are unable to express their pain. This study investigated whether there exists an association between severity of aphasia and overall pain medication use as indicated (1) by the proportion of individuals medicated according to aphasia severity and (2) by the dosage of pain medication used according to aphasia severity.

METHODS

The study involved a retrospective chart review of 207 charts of patients with stroke admitted to the Jewish Rehabilitation Hospital (JRH), Laval, Canada. Patients were classified into three groups according to level of expressive aphasia: those without aphasia, those with mild-to-moderate aphasia, and those severe aphasia. Information on medications used primarily for pain management was elicited for the first 21 days and the last 5 days of hospitalization. Any substitution, increase, elimination, or addition of pain medication during hospitalization was also monitored.

RESULTS AND CONCLUSIONS

While the findings indicate that pain medication prescriptions were similar for all patients, a significantly smaller number of individuals with aphasia received pro re nata (prn) "as required" pain medication when compared with those without aphasia, for the first 21 days and for the last 5 days of hospitalization at the JRH. Similarly, when daily dose was monitored for the same time periods, individuals with aphasia were found to have received less medication for pain than those without aphasia.

Can epileptologists without access to intracranial EEG use reliably the International League Against Epilepsy classification of the localization-related epileptic syndromes? A stereo-electroencephalographic study

The goal of the present study was to investigate the reliability of clinical and electroencephalographic (EEG) criteria for the classification of localization-related epileptic syndromes as listed in the Proposals of Revised Classification of Epilepsies and Epileptic Syndromes 1989 (ICE). ICE distinguishes between multiple syndromes within epilepsies of a given lobe. Intracranial recordings were the main element in the development of the revised ICE. Considering that most epilepsy centers have no access to such invasive techniques for precise anatomic localization, it was of interest to assess how accurately the seizure origin could be determined from the scalp EEG and clinical data as reported in ICE. In this retrospective study, we compared the accuracy of the topographic diagnosis made by two groups of physicians evaluating the same patients-one group with and the other without access to results of stereo-EEG (SEEG). Medical files of 87 patients with intractable localization-related epilepsy were analyzed: 38 with frontal, 37 with temporal, 10 with parietal, and 2 with occipital lobe epilepsy were included in the study. All patients underwent previous SEEG and successful cortectomy. Minimum follow-up was 5 years. In most cases, noninvasive techniques and criteria suggested by ICE allowed topographic diagnosis of focal epilepsies according to brain lobe involvement. More detailed diagnosis, localizing the origin of critical activity within a lobe, was often unreliable. Further data are required for a definition of the epileptogenic zone. A spatiotemporal evaluation of critical events, including the intracranial EEG recording, remains the best method for topographic diagnosis of localization-related epilepsy.

The impact of a decision process upon scalp recorded premovement potential

Twelve normal subjects were asked to select one finger after a warning signal and to move it. Using different modes of averaging the EEG responses, it is shown that: (i) the selection of a finger is accompanied by a distinct negative slow potential consisting of a rapid set-up and a following plateau which is the most prominent under the Fz electrode, and (ii) the decision process, when dispersed within a large interval in repeated trials, gives rise to a slow progressive increase of negativity resembling the early component of premovement slow cortical potential from the classical self-paced paradigm.

[Multiple cortical photolesions and penicillin epileptogenic focus. Study of a model in rabbits]

Inactivation of an epileptogenic focus by dividing it into sub-unities unable to maintain epileptic activity has been demonstrated in animals. Based on these experiments, multiple subpial transections have been performed in patients suffering from partial drug-resistant epilepsies when resection of the epileptogenic cortex was not possible. In order to develop a new surgical technique for such epilepsies, the authors present an initial study of multiple cortical laser photolesions on the rabbit brain. The aim of this study is to assess the histological lesions created on the cortex with a laser at a chronic stage, and to compare the electrical paroxysmal activity of a penicillin focus on the laser irradiated cortex and on the non radiated cortex in the same animal. Twenty-five adult albino rabbits were used for this study. Both hemispheres of 19 rabbits have been exposed; 14 to 35 photolesions in a network were performed on one hemisphere using a 1.064 microns wavelength Nd-YAG laser. Six to twenty-one days later, a penicillin-induced focus was created on both hemispheres, a corticographic study was performed, and each animal was sacrificed for histological study of the brain. For the 6 last animals a high-power 0.805 micron wavelength diode laser was used with the same protocol. Histological study was solely performed in order to compare the effects of both lasers. In 11 animals electrocorticographic control was reliable. Time to first spike occurrence after penicillin application was significantly increased on the treated hemisphere as compared to the untreated one (1' to 14'30" and 10" to 6', respectively; p < 0.01) and the number of spikes per minute at early and late counts was significantly smaller on the treated hemisphere as compared to the untreated one (1 to 29 and 2 to 70, respectively; p < 0.02). Histologically the lesions appeared as cone-shaped coagulation necrosis surrounded by an area of macrophagic reaction, angiogenesis and gliosis. With the diode laser, some lesions included ischemic changes extended in the white matter. This study demonstrated the possibility of creating limited and reproducible photolesions using the laser light energy, without extensive destruction of the cortex. These lesions were reaching from one third to the totality of the cortical depth, depending on laser exposure parameters. This study also demonstrated that these photolesions arranged in a network and at a chronic stage were associated with a significantly reduced paroxysmal activity of a penicillin focus when compared to intact cortex. Since such lesions did not totally isolate cortical sub-unities, spiking was still recorded from the irradiated cortex, but at a lower rate, suggesting a disorganization of the local neuronal network responsible for paroxysmal activity.

Readiness potentials related to self-initiated movement and to movement preceded by time estimation: a comparison

Two procedures for eliciting premovement potentials were compared: (1) the estimation of a 3 s interval elapsed after a warning auditory signal, and (2) classical "self-pacing". Eleven healthy right-handed subjects participated in the experiment, EEG records from scalp electrodes placed at CZ, C3+ and C4+ were analyzed. It has been shown that both procedures induced similar premovement potentials except that in the first procedure the early component of the potential was longer. The time estimation itself induced a negative slow potential consisting of a rapid set-up and a subsequent plateau.

Intracerebral recordings of slow potentials in a contingent negative variation paradigm: an exploration in epileptic patients

While exploring epileptic patients with intracerebral multilead electrodes, we applied a forewarned reaction time task with two successive sound stimuli, a paradigm that is known to elicit a contingent negative variation (CNV). The second, imperative sound stimulus was followed by a hand or a foot movement. Eleven patients suffering drug-resistant partial epilepsies were tested. The slow potentials developing during the time between the two stimuli were usually not typical CNVs (sometimes comprising multiple successive components with distinct polarities). Such "CNV-like" potentials were obtained from two main cortical zones: a central one including premotor, motor, supplementary motor, postcentral and cingulate areas; and a temporal zone, mainly including the auditory cortex and its vicinity, and in some cases the amygdala. This restricted localization contrasted with the broader extent of the CNVs on the scalp. Intracerebral CNV-like events were obtained from both hemispheres, independent of the side of the performed movement. In some patients, readiness potentials (RPs) were also recorded for comparison and displayed a more restricted extent, being present only on the contralateral motor cortex and bilaterally in the supplementary motor areas. Our data suggest that the last part of the CNV cannot just be identified with the RP.

Intracerebral recording of movement related readiness potentials: an exploration in epileptic patients

Readiness potentials (RPs) preceding voluntary self-paced limb movements were recorded intracerebrally in 13 patients suffering drug resistant, intractable epilepsy. Multilead depth electrodes were positioned using the Talairach's coordinate system; they allowed simultaneous recording from the external and mesial cortices and from the interposed white matter during self-paced unilateral hand or plantar flexions. Our intracerebral explorations have shown RPs in the primary motor cortex (MC) contralateral to the movement and in both supplementary motor areas (SMAs), indicating that at least 3 cortical sites become active before the movement. At variance with the scalp RPs recorded in the same patients, the intracerebral potentials were either negative, or positive, depending on the recording site. No consistent differences in duration and time of onset could be established between the MC and the SMA RPs, at least with the used time resolution. RPs were only occasionally observed in the parietal cortex and hippocampus and none were recorded from the amygdala, the temporal, temporo-occipital, prefrontal, frontal and cingular cortices. The wide topographical distribution of the scalp RPs may not be fully explained by the above intracortical findings, leaving the possibility that other generators exist, whose locations remain to be determined.

Laminar analysis of the origin of the various components of evoked potentials in slices of rat sensorimotor cortex

In slices of rat sensorimotor cortex, extracellular field potentials evoked by electrical stimulation of the white matter were recorded at various cortical depths. In order to determine the nature of the various components, experiments were performed in 3 situations: in a control perfusion medium, in a solution in which calcium ions had been replaced by magnesium ions to block synaptic transmission, and in cortices in which the pyramidal neurons of layer V had been previously induced to degenerate. In the control situation, the response at or near the surface was a positive-negative wave. From a depth of about 150 microns downwards, the evoked response consisted usually of 6 successive components, 3 positive-going, P1, P3 and P6 and 3 negative-going, N2, N4 and N5. P1 and N4 were apparent in superficial layers only. The amplitude of the remaining waves was variable in the cortex but all diminished near the white matter. The early part of the surface positive wave arises from a non-synaptic activation of superficial elements, probably apical dendrites. The late part of the surface positive wave and the negative wave are due to the synaptic activation of neurons located probably in layer III. The large negative wave N2 represents principally the antidromic activation of cell bodies and possibly of proximal dendrites of neurons situated in layers III, IV and V, though the compound action potentials of afferent and efferent fibers may contribute to a reduced part to its generation. The late components N4 to P6 are post-synaptic responses. The negative component N5, the amplitude of which is largest in layers III and IV, represents excitatory responses of neurons located at various depths in the cortex. The nature of the positive component P6 is less clear, although the underlying mechanism might be inhibitory synaptic potentials.

Suppression of motor seizures after specific thalamotomy in chronic epileptic monkeys

In the monkey with a chronic motor epileptogenic focus, thalamic lesions restricted to the anterior part of the ventro-postero-lateral nucleus produced a long-lasting improvement, leading in most cases to almost complete seizure suppression. This improvement was attributed to the interruption of a long-loop recurrent excitatory mechanism, involving muscular afferents which are known to relay in the thalamic region where lesions were produced. The specific nature of this effect was suggested by the preliminary results of lesions performed in thalamic regions with non-specific cortical projections. Compared with the pre-lesional situation in which focal activity resulted in permanent motor troubles, the post-lesional state did not show any additional motor deficit. It is concluded that such lesions could be a new approach to controlling intractable motor epilepsies in man.

Penicillin epileptogenic focus in the rat: requisites for transcortical reflex triggering

Epileptiform discharges elicited by natural or electrical stimulations, proprioceptive or cutaneous, were studied in the rat with an experimental acute focus induced by penicillin application in the motor area. EEG paroxystic spikes were easily triggered with restricted foci (0.5 to 1 mm2) located in the representation area of the stimulated region. However, despite the large overlap of sensory and motor cortical limb areas in the rat, EEG spikes, either spontaneous or triggered, were followed by muscular jerks only with much larger foci: at least 2 and 4 mm2, respectively, for anterior and posterior limb areas. Cutaneous stimulations were the most efficient in discharge production; however, discharges were triggered indifferently by muscular or cutaneous afferent fibers in about three-fourths of the cases. The temporal relation between EEG spike and myoclonic jerk were very close. A latency analysis (delay between triggered EEG spike and EMG response, parallel latency fluctuation of both phenomena, delay between spontaneous EEG spike and jerk) supported the hypothesis that a transcortical reflex mechanism, rather than a spinal excitability rebound, was involved in the jerk genesis. Iontophoretic ejection of penicillin within layers III-IV resulted in the development of electroclinical paroxysms. However, similar penicillin ejection within layer V, did not allow efferent discharge production. It is concluded that the involvement of a large surface or volume of cortical tissue is required to produce efferent discharges following EEG paroxysms. This observation is likely related to the unexpectedly wide representation of individual muscles at the motor cortical level.

A reappraisal of rat motor cortex organization by intracortical microstimulation

The organization of the motor cortex was reinvestigated with intracortical microstimulation, in light-anaesthetized (ketamine) rats. A posterolateral (PL) vibrissae area was found in addition to the rostral one, and blinks of the contralateral eyelids were elicited from a part of this PL area. Several cortical representations such as neck or tail were largely overlapping with neighbouring areas. Vegetative effects (mainly myosis and swallowing) were obtained from a medial cortical strip. Within the PL vibrissae area, a topical arrangement related to the vibrissal rows was observed, whereas in the leg areas, no individual representation of muscles could be evidenced. These results are compared with the maps previously published, and discussed in terms of specificity, musculotopy and overlapping of motor areas.

[Nasogenial flaps]

A large epidermoid carcinoma of the lower lip in an elderly patient was treated by excision followed by reconstruction by means of a double nasogenial flap. The postoperative course was complicated by necrosis and then rejection of the flap. Spontaneous healing assisted by local treatment produced a satisfactory functional as well as esthetic result.

The transcortical reflex triggered by cutaneous or muscle stimulation in the cat with a penicillin epileptic focus: relative importance of regions 3a and 4

After establishment of a cortical penicillin epileptic focus in the cat, stimulation of an anterior paw muscle can evoke a late myographic response (LMR) in the same muscle via a transcortical reflex. It is shown here that (1) an LMR can also be obtained with cutaneous stimulation in the region of the muscle; (2) an LMR cannot be elicited when the focus in on area 3a; (3) after inactivation of area 3a by TTX, the motor cortex evoked potential and spike thresholds are increased for proprioceptive but not for cutaneous stimulation, and the LMR persists. It is concluded that area 4 is the critically important structure for the triggering of an LMR. The results concerning area 3a are discussed in terms of this region's efferent connections to the motor cortex and to the spinal cord.

[Proprioceptive afferents of the transcortical reflex in motor epilepsy:localisation of their thalamic relay in the cat (author's transl)]

In the Cat with a penicillin motor focus, a transcortical reflex (RTC) can be triggered by stimulation of the muscle or the cutaneous branch of the radial nerve (DR - SR). We tried here to identify at a suprabulbar level, the proprioceptive pathway involved in triggering RTC. Cerebellar ablation did not modify the reflex. On the other hand reversibly inactivation of a rostral-dorso-medial part of VPL (VPLr) receiving short latency proprioceptive afferents, reversibly abolished the TRC elicited through DR stimulation, while SR stimulation was still effective. It is thus assumed that muscle and cutaneous afferents responsible for eliciting the RTC run in parallel pathways with distinct relay zones within the VPL nucleus.U

[Transcortical reflexes of proprioceptive origin and motor epilepsy (author's transl)]

The long-loop reflex involved in the triggering of paroxysmal activities by proprioceptive afferents is examined in monkeys with a chronic alumina focus and in cats with an acute penicillin focus. Electrical stimulation of a tibial nerve in monkeys as well as muscle stretch in cats elicit a cortical 'evoked spike', i.e., an evoked potential followed by an epileptic spike, accompanied by one or two motor bursts in the muscles concerned. With a very small acute focus, this transcortical reflex is shown to be quite topical: muscles in the vicinity are not affected. Relationships between evoked spike and myoclonic jerk are examined and it is shown that motor efferents usually follow the pyramidal tract. The concept of a transcortical reflex of proprioceptive origin is discussed on the basis of data collected from these models.