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Biomedical subjects

R Bertin

Publications and source records attributed to R Bertin.

At least 19 recordsLinked to original sources
PubMed1999

Effects of acute asphyxia at birth on subsequent heat production capacity in newborn pigs.

The effect of acute asphyxia at birth on subsequent ability to produce heat was investigated in 30 newborn pigs. A model of experimentally induced asphyxia consisting of the prevention of breathing within the first four minutes of life was used. Blood was sampled from an umbilical artery catheter within the first 75 minutes of life for blood gas, pH, glucose, lactate and catecholamine analysis. After the treatment and 24 hours later, heat production capacity, shivering intensity and rectal temperature were measured 10 degrees C below thermoneutrality. Effects on blood gas parameters were severe but transient whereas alterations in carbohydrate metabolism were maintained during the first 75 minutes (P < 0.05). Acute asphyxia at birth induced only minor alterations of thermoregulatory abilities during the first day of life: rectal temperature was lower one hour after birth (P < 0.05) and the postnatal increase in heat production capacity was less pronounced than in controls. It is suggested that the lower viability usually reported for piglets suffering from asphyxia during delivery is most likely to result from reduced vigour and colostrum intake, as well as altered carbohydrate metabolism early after birth.

Animals↗
PubMed1997

Effects of fasting and refeeding on energetic metabolism of cold acclimated rats.

In rats acclimated at 5 degrees C or 28 degrees C (thermal neutrality), overnight fasting induced decreases in body and brown adipose tissue (BAT) weights and led to a larger decrease in resting metabolism (RM) in the 5 degrees C rats than in the 28 degrees C group. Refeeding significantly enhanced RM (diet-induced thermogenesis) in a greater extent in 5 degrees C than in 28 degrees C rats. This effect was inhibited by propranolol (beta adrenergic receptor antagonist) in 28 degrees C but was only halved in 5 degrees C rats. The capacity for nonshivering thermogenesis as determined by norepinephrine infusion was reduced by fasting only in 28 degrees C group; it remained unchanged in cold acclimated rats despite the large lipid utilization induced by fasting.

Acclimatization↗
PubMed1997

[Value of external fixation in proximal tibial fractures].

PURPOSE OF THE STUDY: This study was a retrospective analysis of 39 proximal metaphyseal tibial fractures treated by Orthofix fixator in two trauma departments. MATERIAL AND METHOD: There were 28 men and 10 women with a mean age of 49.5 years. 13 pedestrians were stroked by a car and 18 had a traffic accident on a motorcycle. In 27 cases, the fracture was open with following Cauchoix grading: 15 types 2, 6 types 1 and 6 types 3. All fractures were partially or totally included in the proximal epiphyseal square of the AO system. 14 fractures were metaphyseal, 13 diaphyso-metaphyseal and 12 had an articular irradiation. All external fixations were performed using the Orthofix device, with image intensification. A partial weight bearing was allowed for 2.4 months as an average and full weight bearing at mean 3.7 months. 7 skin grafts, 2 micro surgical (latissimus dorsi) and 2 local flaps were necessary. RESULTS: In 3 patients this technique failed. 3 patients had an autologous bone graft at the metaphyseal and 2 at the diaphyseal fracture site. 30 patients healed without other procedure after an average delay of 5.5 months. During the healing and weight bearing time, 6 frontal deformities appeared and 5 flexion contractures were not reoperated. With a minimum follow up of one year (mean 3 years) 22 fractures had no deformity, 8 had a valgus deformity (5 degrees to 10 degrees) and 3 a varus deformity (6 to 17 degrees). For the 25 patients with an isolated proximal tibial fracture, 11 (44%) had an excellent functional result (no pain, full range knee motion, normal daily activity); 12 (48%) had a good result (episodic pain, minimally knee discomfort, flexion limitation). DISCUSSION: Orthofix fixator appear to be a good solution for comminuted fractures. These fractures have anatomical and epidemiological particularities. AO classification system is not useful; a new one is proposed. External fixator must be placed meticulously after closed fracture reduction.

Accidents, Traffic↗
PubMed1996

Effects of partial sympathectomy of brown fat or of adrenomedullectomy on catecholamine metabolism in cold-reared rats.

1) The aim of this work was to study the effects of surgical denervation of the interscapular brown adipose tissue (IBAT) and of bilateral adrenal demedullation on cold adaptation of rats. 2) After sympathectomy in the 28 degree C rats, there were substantial decreases in the IBAT NE basal level and turnover rate but no modifications in the heart and adrenals. In the 16 degree C rats there were also decreases in the basal level and turnover rate of the IBAT NE but, in addition, significant increases in levels and turnover rates of NE in the heart and of epinephrine in the adrenals. 3) Bilateral adrenal demedullation led to increases in the NE basal level and turnover rate in the IBAT and the heart in the 16 degree C rats; no effects were observed in the 28 degree C rats. 4) It is concluded that in rats born and reared in a mild cold environment a compensatory stimulation of catecholamine production and turnover rate occurs in some organs after a partial sympathectomy of BAT or bilateral adrenal demedullation.

Adipose Tissue, Brown↗
PubMed1996

Metabolic changes associated with sustained 48-hr shivering thermogenesis in the newborn pig.

Metabolic changes associated with sustained 48-hr shivering thermogenesis were studied in piglets maintained at 34 (thermoneutrality) or 25 degrees C (cold) between 6 and 54 hr of life. Despite their high shivering activity and elevated heat production, cold-exposed piglets exhibited a slightly lower rectal temperature than thermoneutral animals (-1.1 degrees C; P < 0.01) at the end of the treatment. The enhancement of heat production and shivering activity were associated with a decrease in muscle glycogen (-47%; P < 0.05) and total lipid content (-23%; P < 0.05), a reduction of blood lactate levels (P < 0.05) and an enhancement of muscle cytochrome oxidase activity (+20%; P < 0.05) which suggests that muscle oxidative potential was increased by cold exposure. Potential for capturing lipids (lipoprotein lipase activity) was also higher in the red rhomboideus muscle (+71%; P < 0.01) and lower in adipose tissue (-58%; P < 0.01) of the cold-exposed piglets. Measurements performed at the mitochondrial level show no changes in rhomboideus muscle, but respiratory capacities (state IV and FCCP-stimulated respiration) and intermyofibrillar mitochondria oxidative and phosphorylative (creatine kinase activity) capacities were enhanced in longissimus dorsi muscle (P < 0.05). These changes may contribute to provide muscles with nonlimiting amount of readily oxidable substrates and ATP necessary for shivering thermogenesis. A rise in plasma norepinephrine levels was also observed during the second day of cold exposure (P < 0.05).

Animals↗
PubMed1996

Effects of the level of asphyxia during delivery on viability at birth and early postnatal vitality of newborn pigs.

Newborn pigs (n = 117) were used to provide information on the relationships of degree of asphyxia during delivery, viability at birth, and some striking aspects of postnatal vitality including survival, interval between birth and first udder contact and between birth and first suckling, rectal temperature at 24 h of life (RT24), and growth rate over the first 10 d of life. The degree of asphyxia at birth was estimated from cord blood pCO2, pH, and lactate levels. Onset of respiration, heart rate, skin color, and attempts to stand during the first minute after birth were used to estimate the viability score. Neonatal asphyxia, i.e., decreased blood pH and increased blood pCO2 and lactate, was associated with the production of unusually high levels of catecholamines. The degree of asphyxia increased with late position in the birth order (P < .01) and was higher in piglets born posteriorly (P < 0.5). Further, the average blood pCO2 within a litter increased (P < .05) with litter size. The was an inverse relationship between the degree of asphyxia and the viability score (P < .001). Highly viable piglets reached the udder more rapidly (P < .001) and had a higher RT24 (P < .001) than those of low viability. Plasma glucose concentrations increased with blood pCO2 and plasma epinephrine concentrations (P < .001). Neonatal asphyxia reduced postnatal vitality by delaying the first contact with the udder (P < .03) and was associated with a lower RT24 (P < .05), growth rate (P < .001), and survival over 10 d (P < 0.06). These variables, i.e., interval between birth and first udder contact, RT24, and growth rate, were correlated with birth weight (P < .001); RT24 was also shown to decrease (P < .001) with the time taken to reach the udder. Overall, results suggest that piglet suffering from asphyxia during delivery are less viable at birth and less prone to adapt to extrauterine life.

Animals↗
PubMed1995

Spatial navigation of staggerer and normal mice during juvenile and adult stages.

Staggerer mutant mice were compared to normal mice of two different ages (2-6 mo) in two tasks requiring navigational skills in a circular maze visible platform condition and a T-maze. Staggerer mutants had higher latencies than normal mice in both tests. The performance of normal mice worsened with age for both tests. The aging factor interacted with the genotype factor only in the circular maze, where the mutant-nonmutant differential was wider among juvenile animals. In neither task was there evidence of a more pronounced impairment with aging in staggerer mutants. It remains to be determined in this mutant at more advanced stages of aging or in other models of chronic neural disease whether early neuropathology accelerates brain aging.

Aging↗
PubMed1995

Cold-induced changes in circulating levels of catecholamines and thyroid hormones are modulated by energy intake in newborn pigs.

Newborn pigs were kept at a low ambient temperature from 6 until 54 h of age and supplied with a limited (LI, 415 g (kg body weight)-1) or a high (HI, 655 g (kg body weight)-1) intake of milk. At the end of the treatment, both groups had similar deep body temperatures and metabolic rates. However, plasma adrenaline and noradrenaline levels were, respectively, 5.8- and 3.0-fold lower (P < 0.01) in HI than LI piglets, whereas plasma 3,5,3'-triiodothyronine (T3) was 1.5-fold higher (P < 0.01) in HI piglets. It is concluded that the hormonal control of cold-induced thermogenesis is modulated by energy intake, with catecholamines and thyroid hormones acting in a closely related and complementary manner.

Aging↗
PubMed1995

Hemodialysis-related lesions of the hand.

Chronic hemodialysis patients often have lesions of the hands characterized by distinctive etiopathogenic mechanisms and functional consequences. We conducted a prospective cross-sectional study in 116 patients with a mean age of 55.9 years and a mean hemodialysis duration of 8.17 years. Carpal tunnel syndrome was present in 28.4% of patients. Median nerve entrapment was bilateral in a large proportion of cases. Wasting of the lateral thenar muscles was often present at diagnosis, denoting advanced nerve compression. Amyloid was demonstrated in the carpal tunnel in 74% of cases of carpal tunnel syndrome. Digital flexor tendon lesions responsible for trigger finger or restriction of active flexion were seen in 21.5% of patients. Erosive arthropathy manifesting as deformities, pain and loss of function affected the distal interphalangeal joints in 11% of patients and the proximal interphalangeal joints or trapeziometacarpal joint in a smaller proportion of patients. Thirty per cent of patients had bony cysts located in the carpometacarpal area, carpal bones, or distal forearm bones; communication with the adjacent joint space was seen occasionally, and intracarpal derangement was a feature in some patients. Most patients had several types of lesions. The rate of occurrence of hand lesions increased markedly after ten years on hemodialysis, with devastating functional consequences.

Adult↗
PubMed1995

[Stabilization of the hindfoot by talonavicular arthrodesis. Results apropos of 50 cases].

UNLABELLED: Hindfoot stabilization can be obtained by an isolated talonavicular arthrodesis as well as a triple arthrodesis. MATERIAL: There were 27 cases of unstable neurological foot, 13 cases of Rhumatoid foot, 7 cases of flat feet and 3 cases of post-trauma arthritis of the talonavicular joint. The procedure was, in all cases, a talonavicular arthrodesis, associated in some cases to a lengthening of the Achilles tendon, tendon transfer and forefoot correction. METHOD: 50 cases were reviewed with a mean follow-up of 40 months. RESULTS: There were 18 per cent cases of non-union. This could be explained by 2 technical errors: bad cartilagenous resection of the surfaces and unstable bone fixation. No subtalar mobility was noted in all cases. Only one case had a midtarsal mobility associated to a non-union. 39 feet had a normal heel axation. In most cases functional improvement was significant with a painless gait. DISCUSSION: Hindfoot stabilization can be obtained by an isolated talonavicular arthrodesis. Non-union could be avoided by a better surgical technique and a cast immobilization of 2 and a half months. The pre-operative deformities should be reduced manually, because isolated fixed valgus and varus can not be corrected by an isolated talonavicular arthrodesis. In conclusion, the indications are: An early valgus deformity of the hindfoot in rhumatoid arthritis. The aim is to avoid a fixed valgus deformity. Neurological induced equino varus deformities specially after stroke and other reducible neurological deformities. Flat foot due to posterior tibialis insufficiency. Isolated arthritis of the talonavicular joint.

Adult↗
PubMed1994

Serotonin level and turnover rate in brown adipose tissue of developing rats.

The level and turnover rate (TR) of serotonin (5-HT) were determined in the brown adipose tissue (BAT) of rats born and reared at 28 degrees C and 16 degrees C. The serotonin/norepinephrine ratio was high in BAT of both groups for the first 2 days. Thereafter it fell. During the first 3 days, the TR was three times higher in 16 degrees C rats than in 28 degrees C rats. A similar difference was observed for the 5-HIAA/5-HT ratio during that period. It is concluded that 5-HT may act on BAT thermogenesis in cold-exposed pups but its mechanism of action is still hypothetical.

Adipose Tissue, Brown↗
PubMed1994

[Functional exploration of brown adipose tissue using beta3 agonists].

In view to utilize beta 3 adrenoceptor agonists for the investigation of body lipid metabolism, a study of the effects of BRL 37344 on the functional activity of the brown adipose tissue was performed in the Rat. It is known that this tissue is the principal site of heat production for nonshivering thermogenesis mainly due to the oxidation of fatty acids under the control of norepinephrine (NA) released from the sympathetic nervous system. In order to stimulate the activity of the tissue, rats were reared at 16 degrees C. When they were one month old, they were divided in two groups; one group received a surgical sympathectomy of the interscapular brown adipose tissue (TABI) (S group); the other group was sham-operated (T group). The resting metabolism was estimated by the continuous measurement of O2 consumption and CO2 release, at an ambient temperature of 25 degrees C. The animal capacity for nonshivering thermogenesis was determined by increased O2 consumption following i.p. administration of NA or BRL 37344. In the S group a large decrease in TABI NA content and a decrease in resting metabolism were observed. In both groups VO2 was increased by the two drugs; the increase was linearly related to the dose of BRL (between 2.5 to 10 micrograms/kg); but it was 3 times as high in the T group as in the S group. Moreover, the effect of BRL was 40 fold greater than the effect of NA. These results seem to indicate that, in cold reared rats, a part of nonshivering thermogenesis may be mediated by the beta 3 receptors of the brown fat. It may be concluded that the rats born in cold conditions are good models to study the role of beta 3 receptors in the energetic activity of this tissue very profuse in infant but not in adult man.

Adipose Tissue, Brown↗
PubMed1993

[Surgery of the foot in equinus deformity in hemiplegic adults].

The authors report the results of surgical treatment of the equinus deformity of the foot in adult hemiplegia performed on 23 patients with a long term follow-up for 20 of them. Surgical treatment required two phases. Firstly, a spasticity correction by scopiform neurotomy of the posterior tibial nerve: this operation had to be done 14 times because of the importance of the spasticity. Secondly, a phase of truly orthopaedic surgery which involved successively, a treatment of the equinus deformity by lengthening of the Achilles tendon, a restoration of the dorsal flexion by anterior muscle transfer and some complementary operations on the forefoot. An astragalo-scaphoid arthrodesis was associated in the 13 most recent cases. Results were subjectively judged very good or good for 17 patients. Objectively, walking appliances have been reduced, gait was more secure and a greater autonomy has been reached. However, the goals of this surgery are limited as it has no incidence on central interferent lesions and neuropsychological troubles resulting from brain damage. The quality of the result is, in other respects, conditional upon the gait pattern of the whole limb, particularly upon the importance of the flexion of the knee during the step cycle.

Achilles Tendon↗
PubMed1993

Postnatal development of nonshivering thermogenesis in rats: effects of rearing temperature.

A comparative chronological study (from 1 to 33 days post partum) was performed to establish the capacity for nonshivering thermogenesis (NST) in rats born and reared at 28 degrees C and at 16 degrees C. The resting metabolism measured at 33 degrees C was higher in the 16 degrees C rats than in the 28 degrees C rats from the 3rd day. When expressed per weight or per surface area units it was higher in 16 degrees C pups than in 28 degrees C pups until the end of the 3rd week. In fact the resting metabolism was significantly proportional to different powers of weight (W0.67 at 16 degrees C and W0.75 at 28 degrees C) during the suckling period. At birth, respiratory quotient (RQ) was the same in both groups (0.70); it increased slowly to the end of the 3rd week (about 0.80). During the 3rd week RQ was lower in 16 degrees C rats than in 28 degrees C animals. This indicates that 16 degrees C rats are more dependent on the milk supplied by their mother. After weaning there were no differences in RQ values (0.90). Rectal temperature was low in both groups on day 1 (about 32 degrees C). It increased until weaning when it stabilized at 37 degrees C. From day 1 to day 18, it was significantly lower in cold reared rats. The capacity for NST was measured by investigating the effect of an injection of norepinephrine (NE) on the metabolic rate at 33 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Acclimatization↗
PubMed1991

Effects of the rearing temperature on the temporal feeding pattern of the staggerer mutant mouse.

The temporal feeding pattern of the staggerer mutant mouse was tested under two thermal rearing conditions, 28 degrees C and 22 degrees C, and compared to that of the normal mouse. At a temperature of 28 degrees C, the mutants were observed to eat more than the normal mice did although they showed a drastic body weight deficit. At 22 degrees C, this peculiarity was still observed, but with an altered feeding pattern, wherein the mutants ate as much during both the dark and light phases.

Animals↗
PubMed1991

Catecholamine turnover in heart and adrenals of young rats: effects of rearing temperature.

1. A comparative chronological study (from birth to one month of age) was performed to establish the levels and turnover rates of catecholamines in the heart and adrenals of rats born and reared at 28 and 16 degrees C. 2. In the heart, cold induced marked increases of the norepinephrine level and turnover rate only from the second week of age. 3. In the adrenals there was considerable early stimulation of epinephrine production, but only in 28 degrees C rats. 4. The differences observed in the stimulation of the sympathetic nervous system according to the rearing temperature are possibly due to the behavior of the mother in warming the pups.

Adrenal Glands↗