Hydrolyzed collagen improves bone status and prevents bone loss in ovariectomized C3H/HeN mice.

SUMMARY: This study evaluates the effect of hydrolyzed collagen (HC) on bone health of ovariectomized mice (OVX) at different ages. Twenty-six weeks after the OVX procedure, HC ingestion was still able to improve significantly bone mineral density (BMD) and some femur biomechanical parameters. Moreover, HC ingestion for 1 month before surgery prevented BMD decrease. INTRODUCTION: HC can play an important role in preserving BMD before osteoporosis appears. The aim of this study was to evaluate the effect of HC on bone health of ovariectomized mice at different ages. METHODS: Female C3H mice were either OVX at 3 or 6 months and fed for 6 months (first experiment) or 3 months (second experiment) with diet including 0, 10, or 25 g/kg of HC. In the second experiment, one group received HC 1 month before surgery, and two groups received the supplementation immediately after surgery, one fed ad libitum and the other by gavage. Mice treated with raloxifene were used as a positive control. BMD, femur intrinsic and extrinsic biomechanical properties, and type I collagen C-terminal telopeptide were measured after 12 and 26 weeks. Food intake and spontaneous physical activity were also recorded. RESULTS: The OVX procedure increased body weight, while food intake decreased, thus suggesting that resting metabolism was decreased. Ingestion of 25 g/kg of HC for 3 or 6 months reduced bone loss significantly in, respectively, 3- and 6-month-old OVX mice. The lowest HC concentration was less efficient. HC ingestion for 3 months is as efficient as raloxifene to protect 3-month-old OVX mice from bone loss. Our results also demonstrated that HC ingestion before surgery prevented the BMD decreases. CONCLUSION: This study confirms that dietary collagen reduces bone loss in OVX mice by increasing the diameter of the cortical areas of femurs and can have a preventive effect.

Peripherally injected cholecystokinin-induced neuronal activation is modified by dietary composition in mice.

The aim of this study was to investigate the effect of long-term nutrient intake on the central response to the anorexigenic gut hormone CCK. C57BL/6 mice were fed one of three diets for 6 weeks: standard high carbohydrate (HC), high fat (HF), or high protein (HP). Assessment of brain response to cholecystokinin (CCK) by manganese-enhanced MRI (MEMRI) showed a reduction in neuronal activity both in an appetite-related area (ventromedial nucleus of the hypothalamus) and areas associated with reward (nucleus accumbens and striatum) regardless of diet. When comparing diet effects, while the HF diet did not induce any change in activity, reductions in MEMRI-associated signal were found in the paraventricular nucleus (PVN) and lateral hypothalamic area (LHA) when comparing the HP to the HC diet. In addition, a significant interaction was found between CCK administration and the HF diet, shown by an increased activation in the PVN, which suggests a decrease the inhibiting action of CCK. Our results put forward that the long-term intake of an HP diet leads to a reduction in basal hypothalamic activation while a high-fat diet leads to desensitization to CCK-induced effects in the hypothalamus.

Peripheral selection of V delta 1+ cells with restricted T cell receptor delta gene junctional repertoire in the peripheral blood of healthy donors.

To characterize the T cell receptor (TCR) repertoire expressed by the V delta 1+ gamma/delta T cell population, we have studied the V delta 1-J delta 1 junctional sequences from peripheral blood samples of healthy donors. We show that, surprisingly, this repertoire is restricted in most healthy adults, with a donor-specific and relatively stable pattern, whereas this repertoire remains unrestricted in infants, and is similar to that of thymocytes. These data contrast with the general assumption that the junctional repertoire of V delta 1+ gamma/delta T cells is extensive, and strongly suggest that peripheral recruitment of V delta 1+ cells bearing particular TCR occurs in humans during the postnatal stage.

Risk factors for mortality in patients with pulmonary infections with non-tuberculous mycobacteria: a retrospective cohort study.

BACKGROUND: Infections with non-tuberculous mycobacteria (NTM) represent an increasing problem. Their clinical relevance is still largely unknown as well as predictors for mortality in affected patients. The objective was to describe prevalence and clinical relevance of different NTM and to identify risk factors for mortality. METHODS: Retrospective cohort study of 124 patients with NTM detection between January 2001 and December 2011. Clinical characteristics like symptoms and radiological appearance were assessed at presentation. The primary outcome was all cause mortality during the follow-up period. Univariate and multivariate survival analyses using Cox proportional hazard models were employed for statistical analysis. RESULTS: Over the study period, the frequency of NTM isolation varied from 4 to 12 patients per year. Twenty-nine out of 124 patients (23%) had a clinically relevant infection, according to the criteria of the American Thoracic Society (ATS). Mycobacterium avium was isolated most frequently, but Mycobacterium kansasii, Mycobacterium malmoense and Mycobacterium xenopi had the highest clinical relevance. Symptoms were mostly diverse and non-specific. On radiology, cavities were observed more frequently than a nodular-bronchiectatic variant or consolidation. In 75% of all patients, follow up time was more than two years. Median survival was 6.5 years (95%CI = 2.7-10.3). Factors significantly influencing survival time were haemoptysis (HR = 0.2, 95%CI = 0.1-0.6) and a consolidation on imaging (HR = 5.1, 95%CI 1.4-18.2). CONCLUSIONS: The presentation of an infection with NTM can be diverse and depends mainly on the causative NTM pathogen. The most important predictor for increased mortality is the radiological appearance of a consolidation.

Practical aspects of indirect calorimetry in laboratory animals.

Oxidation of the energetic substrates by the body is associated with oxygen consumption, carbon dioxide production, and heat release specific to the nature of the energetic substrates being oxidized. Therefore, measurement of respiratory exchanges (indirect calorimetry) is a powerful method to investigate heat production of a living organism. In this article, we review the elementary principles of indirect calorimetry and describe the operating principle of the two most typical devices used to perform indirect measurements of energy expenditure in the laboratory animal: the closed-circuit and the open-circuit. We then discuss some practical aspects of the day-to-day use of these devices: respective advantages and limitations of each technique, data processing, calibration, correction for body-size, and computation of the energy expended for activity. In the second part, we review some of the standard formulas of indirect calorimetry that offer the possibility to obtain more precise information such as the rate of oxidation of carbohydrates (CHO), lipids and proteins if some hypotheses are made on the intensity of lipogenic, ketogenic, and gluconeogenic processes. Finally, a practical example of the measurement of energetic cost of activity and thermic effect of food in the rat is given.

Early induction of angiotensin I-converting enzyme in rat carotid artery after balloon injury.

Several studies have demonstrated the effectiveness of angiotensin I-converting enzyme (ACE) inhibitors in preventing the neointima formation found after denudation of the rat carotid artery by balloon injury. The aim of the present study was to determine the role of ACE in this model and to compare the treatment with the ACE inhibitor ramiprilat with that with the angiotensin II antagonist HR 720. The endothelial layer of the left carotid artery was removed using an inflated balloon catheter. Injured and control vessels were both submitted to histomorphological analysis and DNA content quantification at 2, 4, 6, 8, 12, and 14 days after injury. Evaluation of neointima thickening demonstrated a slow but steady increase of neointima that was significant after day 6 and reached 30% of the lumen in 2 weeks. This was paralleled by an increase in DNA content, which was significant 4 days after injury. ACE mRNA levels were quantified by polymerase chain reaction after reverse transcription. Measurement of ACE mRNA levels revealed a significant upregulation 2 and 8 days after injury, with no significant difference when compared with control tissue at later time points. ACE activity was also significantly enhanced at 2 and 8 days after injury, with no significant difference when compared with control tissue at later time points. In addition, the treatment with ramiprilat was more efficient in reducing neointima formation than that with HR 720. These data underlie the role of ACE in this model of restenosis. The early induction of ACE expression after endothelial injury but before significant changes in the vessel structure suggests that ACE activity might be one of the mechanisms that trigger neointima formation in the rat.

Physiological determinant of hunger, satiation, and satiety.

The initiation and cessation of feeding behavior is explained on the basis of the ischymetric hypothesis (from ISCHYROS meaning "Mighty One" or power). Cellular production of power or "Metabolisme de Fond" (MF) is measured continuously in terms of total body metabolism minus the metabolic costs of locomotion. A drop in MF signals the onset of eating. Eating initiates a rise in MF and when this signal peaks, the feeding process stops. Control of satiation is described in terms of recent neurophysiologic and neuroendrologic factors that influence MF.

Effectiveness and safety of bolus administration of alteplase in massive pulmonary embolism.

Animal studies have demonstrated that thrombolysis with recombinant tissue-type plasminogen activator (rt-PA) is accelerated and that bleeding is reduced when rt-PA is infused over a short period. Previous clinical studies in patients with venous thromboembolism have shown that rt-PA is an effective thrombolytic agent when administered by continuous infusion over 2 to 24 hours. Clinical experience of bolus rt-PA administration in patients with massive acute pulmonary embolism (PE) is, however, limited. A prospective open study was conducted in which 54 patients with massive PE (Miller index > or = 20 of 34) received a 10-minute infusion of rt-PA at a dose of 1 mg/kg. Perfusion lung scanning was used to assess the change in pulmonary perfusion after drug administration. At 48 hours and 10 days, the mean absolute improvements in the perfusion defect were 11 and 31%, respectively. In addition, a significant clinical improvement occurred within 2 hours in 11 of the 15 shocked patients. Five patients died (9%) as a result of persistent shock (3 patients), neurologic damage (1 patient) or intracranial bleeding (1 patient). Major bleeding occurred in 8 patients (15%). Long-term follow-up information was available for 44 of the 49 discharged patients: 2 had died and 12 (27%) complained of persistent exertional dyspnea, 7 of whom had an associated heart or lung disease or chronic thromboembolism at admission. These results suggest that a bolus regimen of rt-PA could provide a convenient approach to thrombolytic therapy in patients with massive PE.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficient coherent combining of widely tunable fiber lasers.

We have experimentally demonstrated coherent combining of 2 and then 4 fiber lasers, with respectively 99% and 95% combining efficiency. The combining method investigated here is based on a multi-arm resonator of interferometric configuration. In spite of its interferometric nature, the multi-arm laser operates without significant power fluctuations, even in an unprotected environment. This occurs when the arm length difference is large enough to introduce spectral modulations of period smaller than the laser bandwidth. We have also experimentally shown that the combining method is compatible with wavelength tuning. A Mach- Zehnder Fiber Laser was tuned over a wide spectral range of 60nm. Theoretically then, we confirm that the combining method can be scaled to a large number of lasers without decreasing the combining efficiency.

Limited small-cell lung-carcinoma - high complete response rate and survival with short intensive chemotherapy and extensive irradiation - results of a pilot-study.

Sixteen patients with limited small-cell lung carcinoma (SCLC) were treated with three monthly courses of intensive chemotherapy (cisplatin: 40 mg/m2/day (D), D1, D2 and D3; cyclophosphamide: 750 mg/m2/D, D4 and D5; adriamycin: 50 mg/m2/D, D5; vindesine: 2 mg/m2/D, D1 and D5; etoposide: 100 mg/m2/D, D1, D2 and D3; methylprednisolone: 120 mg/m2/D, D1 to D5). Thoracic and prophylactic brain plus spinal area irradiations were performed after completion of the third chemotherapy cycle. The complete response rate was 100%. Of these 16 patients, 7 experienced a relapse from 5 to 31 months after completion of treatment. The three-year survival rate was 54%. The main toxicities were hematological (neutropenia and thrombocytopenia) and digestive. We conclude from this pilot study that intensive five-drug chemotherapy is a highly effective regimen for limited SCLC. This intensive chemotherapy regimen and extensive irradiation is feasible without major toxicity. This type of intensive combined-modality program deserves further study to definitely establish its long-term efficacy in localized SCLC.

Metabolic rate and feeding behavior.

According to the ischymetric hypothesis, hunger is induced by the decrease of overall metabolic rate. In order to assess such a mechanism, it was necessary to monitor the muscular contraction-free metabolic rate designated "métabolisme de fond" (MF) in rats that were either resting or moving. MF was then examined in relation to either spontaneous or induced feeding patterns. A computerized open-circuit gas analysis system allowed us to monitor MF and behavior and to show that the onset of a spontaneous meal was preceded by a decrease of MF and its termination is preceded by a rebound of MF. Pharmacological blockade of utilization of both glucose and lipids enhanced feeding only to the extent that it reduced MF. These findings apply to pharmacotherapy because the anorexigenic effect of dexfenfluramine results from the enhancement of MF induced by the capacity of this drug to mobilize endogenous fat reserves and to so provide an endogenous meal that inhibits the exogenous meal. The ischymetric mechanism of hunger does not exclude important modulatory input from hormonal, circadian, and environmental factors in the control of feeding.

An analysis of the diagnostic methods for acute pulmonary embolism.

In spite of numerous sophisticated investigative procedures, acute pulmonary embolism (PE) is very frequently misdiagnosed. In order to improve the diagnostic approach to PE, the sensitivity and specificity of the commonly used methods were reviewed in a group of 421 patients with angiographically proved PE without associated cardio-pulmonary disease. The specificity of diagnostic procedures was, by decreasing order: positive pulmonary angiography (to affirm) = negative perfusion lung scan (to eliminate) greater than chest X-ray much greater than clinical symptoms, positive perfusion lung scan, ECG, blood gas, serum enzymes.

Substrate oxidation during exercise in the rat cannot fully account for training-induced changes in macronutrients selection.

This study investigated spontaneous dietary adaptation to regular exercise in relation to substrate oxidation measured during exercise. Male Wistar rats were offered permanent access to the three sources of macronutrients supplemented with minerals and vitamins. The rats remained sedentary or were trained daily during 3 weeks at moderate intensity (20 m x min(-1), 2 hours). Body weight, total caloric intake, and macronutrients selection were recorded throughout the experiment. Energy expenditure and substrate oxidation were measured before, during, and after an exercise identical for trained and untrained rats (10 m x min(-1) 1 hour). Training reduced body weight gain (2.27 v 5.57 g x day(-1)), increased protein intake (52.6% v 39.2%), and decreased carbohydrate intake (21.3% v 39.5%). Basal and running energy expenditure, as well as glucose and lipid oxidation, remained essentially comparable in trained and untrained rats. The relative contribution of glucose oxidation (Gox) to total energy expenditure decreased during exercise (52.2%, average of all rats) relative to before exercise (60.8%). Gox during exercise was positively correlated with resting Gox before exercise, showing that preexercise substrate oxidation was a strong determinant of running substrate oxidation. However, the slope was smaller for the trained than for the untrained rats, showing that exercise increases Gox less in trained rats than in untrained ones. We conclude from this study that, since food selection but not substrate oxidation changed following training, food intake adapted to substrate requirements induced by regular training and not the contrary. However, large differences remained between the mixture ingested, in which lipids accounted for only 26% of the energy, and the mixture oxidized during exercise, in which lipids accounted for 50.7% of the substrate oxidized. Such a difference may be related to metabolic requirements during the rest of the day and/or to the distribution of macronutrients intake relative to exercise. This question deserves further investigation with recording of macronutrients selection, energy expenditure, and substrate oxidation over 24 hours.

Hindlimb immobilization applied to 21-day-old mdx mice prevents the occurrence of muscle degeneration.

Dystrophin-deficient skeletal muscles of mdx mice undergo their first rounds of degeneration-regeneration at the age of 14-28 days. This feature is thought to result from an increase in motor activity at weaning. In this study, we hypothesize that if the muscle is prevented from contracting, it will avoid the degenerative changes that normally occur. For this purpose, we developed a procedure of mechanical hindlimb immobilization in 3-wk-old mice to restrain soleus (Sol) and extensor digitorum longus (EDL) muscles in the stretched or shortened position. After a 14-day period of immobilization, the striking feature was the low percentage of regenerated (centronucleated) myofibers in Sol and EDL muscles, regardless of the length at which they were fixed, compared with those on the contralateral side (stretched Sol: 8.4 +/- 6.5 vs. 46.6 +/- 10.3%, P = 0.0008; shortened Sol: 1.2 +/- 1.6 vs. 50.4 +/- 16.4%, P = 0.0008; stretched EDL: 05 +/- 0.5 vs. 32.9 +/- 17.5%, P = 0. 002; shortened EDL: 3.3 +/- 3.1 vs. 34.7 +/- 11.1%, P = 0.002). Total numbers of myofibers did not change with immobilization. This study shows that limb immobilization prevents the occurrence of the first round of myofiber necrosis in mdx mice and suggests that muscle contractions play a role in the skeletal muscle degeneration of dystrophin-deficient mdx mouse muscles.

A tryptophan-rich protein diet efficiently restores sleep after food deprivation in the rat.

Sleep depends on the quantity and quality of the diet. Several studies have shown that food deprivation results in a reduction in sleep duration. It has also been demonstrated that in the newborn, the supply of certain essential amino acids improves sleep through their action on the synthesis of specific neurotransmitters. The aim of the present study was to test if the quantity and/or quality of dietary protein could improve the recovery of sleep during re-feeding after caloric deprivation. Sleep parameters were compared in rats fed ad libitum, food restricted during 4 days, or reefed isocalorically after food restriction with three dietary regimens varying in terms of the amount (14% versus 30%) or quality (milk protein or alpha-lactalbumin) of protein. The results showed that sleep recovery, in particular slow-wave sleep, was improved in rats re-fed with alpha-lactalbumin. This result confirms the close relationship between feeding and sleep and suggest that alpha-lactabumin could be used to improve sleep in adult submitted to nutritional disturbances such as food restriction, shift work, Ramadan.

Pulmonary embolectomy: a 20-year experience at one center.

Between 1968 and 1988, 96 consecutive patients with acute massive pulmonary embolism underwent pulmonary embolectomy under cardiopulmonary bypass. The operative mortality rate was 37.5%. We analyzed 12 clinical and hemodynamic variables by univariate and multivariate analyses to assess the predictive factors of postoperative outcome. Multivariate analysis disclosed that cardiac arrest and associated cardiopulmonary disease were independent predictors of operative death. Long-term follow-up (range, 2 to 144 months; mean, 56 months) information was available for 55 of the 60 discharged patients: 6 had died, and 5 complained of persistent mild or severe exertional dyspnea (New York Heart Association class II). These results help assess the preoperative risk in patients undergoing pulmonary embolectomy. They also show that, in the few patients who do not benefit from optimal medical therapy, pulmonary embolectomy remains an acceptable procedure in view of the long-term results.

Spontaneous and 2DG induced metabolic changes and feeding: the ischymetric hypothesis.

A computer-controlled calorimeter which simultaneously measured respiratory exchanges, locomotor activity, and meal patterns, was used to study Total Metabolic Rate (TM), Locomotor Free Metabolic Rate (LFM), and Respiratory Quotient (RQ) in relation to spontaneous and 2DG induced Food Intake in freely-feeding rats. It appeared that spontaneous and 2DG induced feeding was preceded by a consistant drop of LFM starting about five minutes before a meal and reaching its nadir at the onset of a meal. The simultaneous determination of the RQ did not show any systematic change that would have reflected either a lipo- or a gluco-privic origin of the LFM drop and meal onset. Therefore, the results are in agreement with the ischymetric hypothesis of the control of food intake which proposes that the final signal triggering hunger and satiety is the intensity of cell power production (measured in this experiment through the LFM parameter) which is independent of the glucidic lipidic or protidic origin of the substrate(s) supplying power production.

Short-term control of feeding: limitation of the glucostatic theory.

In the rat, the short-term effect on spontaneous feeding of intravenous administration of either glucose or glucose plus insulin was investigated. The infusions lasted 4 hours and covered 170% of rats's previously measured spontaneous caloric intake, while control infusions of saline and saline plus insulin were also made. Feeding patterns in subjects' home cages were recorded. Glycaemia and glycosuria were measured in order to asses glucose utilization. When it was infused alone, glucose was utilized at 95% and so covered 160% of oral caloric requirements, while the reduction of oral intake was only 40%. When insulin was co-infused with glucose, utilization reached 100% and oral feeding was reduced by 70%. Saline infusions did not affect oral feeding, and insulin brought about the expected increase in feeding. It is proposed that the mechanism which sustains feeding should depend on multiple macronutrients utilization rather than on one specific chemical family. Furthermore, the fact that insulin has a clear-cut effect, despite its lipogenetic, i.e., metabolite-sequestering properties, favors the ischymetric hypothesis (based on cellular power-production), rather than the energostatic one (based on yields of nutrients).