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Biomedical subjects

C Perret

Publications and source records attributed to C Perret.

At least 127 records · Page 7Linked to original sources
PubMed1992

[Diabetes mellitus and pancreatic cancer: a case-control study in greater Montreal, Quebec, Canada].

In a population-based case-control study of dietary risk factors in French Canadians in Montreal, a total of 179 cases and 239 controls were interviewed between 1984 and 1988. It was found that the frequency of diabetes was almost three times higher in cases of pancreatic cancer (16%) than in the controls (6%), with an Odds Ratio (OR) of 2.52 and a Confidence Interval (CI) of 1.04-6.11. Fifty per cent of the pancreatic cancer cases had this disease before the cancer was diagnosed, compared with 71% of the controls at the time of the study. Those aged 50 years and over accounted for 75% of the cases and 71% of the controls (diabetic subjects); 68% of the cases were treated with a combination of diet and oral hypoglycemic agents compared with 86% of the controls. Insulin was used by 32% of the cases and 14% of the controls. These results suggest that diabetes may play a major role in the etiopathogenesis of pancreatic cancer in this urban population. A lot of controversy remains about the precise role of diabetes, and further studies are needed for a better assessment and understanding of the mechanisms of this association.

Adult↗
PubMed1991

DNase I-hypersensitive sites are associated, in a tissue-specific manner, with expression of the calbindin-D9k-encoding gene.

We have examined the chromatin structure of a 28-kb chromosomal region containing the gene (CaBP9k) encoding calbindin-D9k in different rat tissues. DNase I-hypersensitive sites (HSs) were probed with DNase I using an indirect end-labeling technique. Duodenal chromatin, where the gene is strongly expressed, contained one major HS (HS4) and three minor HSs (HS2, HS3 and HS5) near the promoter region. The HS4 was mapped just upstream from the promoter region and had the characteristics of a tissue-specific HS. The HS5 was located at the transcription start point, it included the TATA box and its presence was correlated with a promoter function. The duodenal chromatin contained two additional HSs, a major HS (HS1) located approx. 3.5 kb upstream from the cap site and a minor HS (HS6) in the second intron at +0.5 kb. Despite the marked effect of 1,25-dihydroxyvitamin D3 (DHD3) on the CaBP9k mRNA level, the pattern of HSs in duodenal chromatin was unchanged after stimulation with DHD3. The liver chromatin contained one major HS (HS1) identical to the duodenum HS1 (although this tissue does not express CaBP9k). It also contained a liver-specific HS (HS0) 0.1 kb upstream from HS1. The interaction of HS0 with HS1 could explain the absence of CaBP9k expression in the liver. Thus, specific sets of HSs are associated with various functional states of CaBP9k in a tissue-specific manner.

Amino Acid Sequence↗
PubMed1991

Family aggregation of cancer of the prostate in Quebec: the tip of the iceberg.

Cancer of the prostate is one of the most common cancers among males in North America. Although some causative factors have been suggested by several surveys, the etiology of this common cancer is poorly understood. In a case-control study of prostatic cancer in Greater Montreal, 21 of 140 patients with prostatic cancer (15.0%) gave a positive family history of the same cancer, as compared with two cases among 101 (2.0%) population-based controls. This indicates about an eightfold difference in occurrence of cancer of the prostate among first-degree family members of the case group with an odds ratio (OR) of 8.7 and 95% CI, 2.00-38.17. In this report we present the pedigrees of three families (two cases and one control) with four pathologically confirmed cases of cancer of the prostate in each family. This data suggest that a familial predisposition to prostatic cancer may become apparent in later decades of life. In these family aggregations, in addition to the genetic factors, environmental factors may also play an important role in the etiology of the same cancer among family members.

Aged↗
PubMed1991

Esophageal and mouth pressure during sniffs with and without nasal occlusion.

The sniff maneuver has recently been advocated for assessing inspiratory muscle strength. We characterized the relationship between mouth pressure (Pmo) and esophageal pressure (Pes) during sniffs performed with open, semi-occluded, and occluded nose. In seven normal subjects, pressure was simultaneously measured with a mouthpiece (Pmo) an esophageal balloon (Pes) during high- and low-intensity sniffs performed from FRC. With open nose, the mean ratio Pmo/Pes was 0.96 +/- 0.05 (mean +/- SE). The mean ratio Pmo/Pes was not significantly different in high- and low-intensity sniffs. With one nostril occluded, the mean ratio Pmo/Pes was 1.03 +/- 0.04. The ratio Pmo/Pes was significantly higher than with open nose for all sniffs (P less than 0.05) and low-intensity sniffs (P less than 0.01). With both nostrils occluded, the mean ratio Pmo/Pes was 1.06 +/- 0.03, with occasional marked overestimation of Pes by Pmo. We conclude that Pmo generally reflects Pes during sniffs performed with open and semi-occluded nose, but not with complete nasal occlusion.

Adult↗
PubMed1991

Tenascin expression in hyperproliferative skin diseases.

The expression of tenascin, a recently discovered extracellular matrix glycoprotein, was studied by immunohistochemistry in normal human skin and in a number of skin diseases with epidermal hyperproliferation such as psoriasis, basal cell carcinoma, Bowen's disease and solar keratosis. Tenascin expression in the upper dermis of normal skin was found to vary from almost absent to patchy along the basal membrane. Staining was continuous and intense around blood vessels, hair follicles and eccrine sweat ducts. In basal cell carcinoma a marked expression of tenascin was found in the tumour stroma, especially adjacent to the basal membrane surrounding the tumour cell nests. In Bowen's disease and solar keratosis, tenascin expression was found in the dermis next to the keratinocytes. In psoriasis the dermal papillae of clinically involved skin were intensely stained and a continuous band of tenascin was present in the upper dermis along the basal membrane. The distribution of tenascin differed from other known extracellular matrix components.

Animals↗
PubMed1991

Plasma levels of tumor necrosis factor in the adult respiratory distress syndrome.

The purpose of the study was to evaluate the role of tumor necrosis factor alpha (TNF alpha) in the pathogenesis of acute lung injury in critically ill patients. An immunoradiometric assay with an upper normal limit of 9 pg/ml was used to measure plasma TNF alpha levels (pl-TNF alpha) in 34 patients with adult respiratory distress syndrome (ARDS) and in 16 patients in whom, despite the presence of risk factors, ARDS did not develop. Pl-TNF alpha was elevated in 76% of the patients with ARDS (71 +/- 104 pg/ml) and in 48% of the at-risk patients (47 +/- 73 pg/ml); the difference between the two groups was not statistically significant. In 13 patients studied serially from the onset (Day 0) to the fifth day of ARDS, the peak pl-TNF alpha occurred later than Day 0 in seven subjects. Although the highest pl-TNF alpha levels were found in septic patients, moderately elevated values were also observed in 56% of nonseptic subjects. We conclude that plasma TNF alpha level is not a marker of ARDS but rather of shock and sepsis. These results do not exclude a pathogenic role of TNF alpha in acute lung injury since this cytokine could be produced and exert its effects within the lungs. The large incidence of abnormally high could be produced and exert its effects within the lungs. The large incidence of abnormally high plasma TNF alpha levels raises important questions on the role of this toxic cytokine in other disorders occurring in critically ill patients.

Adult↗
PubMed1991

Maximal sniff mouth pressure compared with maximal inspiratory pressure in acute respiratory failure.

Inspiratory muscle strength most often is better reflected by sniff Pes than PImax against occlusion. Furthermore, sniff Pes can be estimated noninvasively by the measurement of sniff Pmo in normal subjects and in patients with respiratory muscle weakness. The aim of this study was to compare sniff Pmo and P.PImax to assess inspiratory muscle strength in patients with acute respiratory failure. The highest pressure was produced by P.PImax in 61 percent of measurements, and by sniff Pmo in 39 percent. Above 35 cm H2O P.PImax yielded the highest pressure in 55 percent of cases and the ratio sniff Pmo/P.PImax was 1.20 +/- 0.54. Below 35 cm H2O, P.PImax yielded the highest pressure in 75 percent of cases and the ratio sniff Pmo/P.PImax was 0.76 +/- 0.35 (p less than 0.02). Thus, measurements of sniff Pmo and P.PImax complement one another for assessing inspiratory muscle strength. However, sniff Pmo underestimates inspiratory muscle strength in patients with severe inspiratory muscle weakness.

Acute Disease↗
PubMed1990

[Survival of HIV-positive patients hospitalized in intensive care for respiratory insufficiency and pneumocystis carinii pneumonia].

Respiratory failure secondary to Pneumocystis carinii pneumonia (PCP) is associated with high mortality in AIDS patients. In a search for prognostic indicators, we reviewed hospital charts of 13 AIDS patients admitted to our intensive care service from 1982 to 1989. Mortality rate was higher from 1982 to 1987 (4/5 patients) than later (3/8 patients). There was no significant difference between survivors and non survivors of this acute episode with regard to sex. HIV risk factors, time elapsed since AIDS diagnosis, vital signs (blood pressure, heart rate, respiratory rate), hemoglobin, white blood cell count, platelets, total and T4 lymphocytes, electrolytes, lactate dehydrogenase, P24 antigen Apache II and SAPS scores and corticosteroid treatment. Higher mortality was associated with more advanced age and an oxygen alveolar-arterial gradient greater than 65 mm Hg with an inspired fraction of oxygen of 0.21. We conclude that only the alveolo-arterial gradient could represent a prognostic indicator of practical interest. It is our belief that improvement since 1988 can be explained by earlier diagnosis and prompt treatment before development of severe lung alterations.

Acquired Immunodeficiency Syndrome↗
PubMed1990

[Lactic acidosis and hyperlactatemia].

Lactic acidosis is a relatively frequent acid-base disorder in a hospital setting. It is defined by the association of an arterial pH inferior to 7.35 and an arterial lactate level superior to 5 mmol/l. Classically, 2 types of acidosis are distinguished on the basis of their mechanisms of onset: the type A, with evident clinical signs of tissue hypoperfusion and the type B, more are, without apparent hypoxia. This last category is observed in various circumstances such as diabetes, acute liver failure, poisoning and, more rarely, inborn errors of carbohydrate metabolism. Treatment aims primarily at the correction of the cause. The efficacy of sodium bicarbonate is presently debated, considering the risk to worsen hyperlactatemia and to induce hyperosmolarity or rebound alkalosis. The administration of dichloroacetate, an activator of pyruvate dehydrogenase, permits to correct partially the lactic acidosis but is not harmless especially in case of prolonged administration. Other therapeutic modalities are evoked. Arterial lactate level is a reliable prognostic index of shock, because blood values do not depend only of the oxygen debt but also of the efficacy of hepatic and renal lactate uptake. Sequential measurements are recommended.

Acidosis, Lactic↗
PubMed1990

[Hospital morbidity and mortality of acute opiate intoxication].

The records of 188 consecutive patients admitted for acute opiate intoxication were analyzed retrospectively to evaluate the morbidity and mortality of opiates. The most frequently used of these drugs were heroin (127 cases) and methadone (41 cases). In 79 cases the opiate was associated with another psychodepressant, usually benzodiazepines, alcohol or barbiturates. Forty-seven percent of the patients were admitted in deep coma, with respiratory arrest in almost every case. The complications observed in 49 patients were: aspiration of gastric contents (n = 24), rhabdomyolysis (n = 22), often associated with myocarditis (n = 13), pulmonary edema (n = 16), convulsions (n = 10), left ventricular dysfunction (n = 5) and lesions of the peripheral nervous system (n = 4). All patients survived, except one who died of cardiac arrest before admission. It is concluded that acute opiate intoxication treated in hospital has an excellent prognosis for life provided no cardiac arrest occurs prior to admission. One quarter of the patients require prolonged stay in an intensive care unit because of complications. The other patients, even when deeply comatose on admission, spend less than 1 day in hospital owing to the specific antagonist available.

Acute Disease↗
PubMed1990

Molecular cloning and characterization of a rat intestinal sucrase-isomaltase cDNA. Regulation of sucrase-isomaltase gene expression by sucrose feeding.

To investigate the regulation of expression of intestinal sucrase-isomaltase (SI) complex in response to sucrose feeding, we isolated a cDNA (RPSI1) encoding partially the pro-SI of rat intestinal mucosa. The clone consists of 1929 mRNA-derived nucleotides, which covered the region including the C-terminal part of the isomaltase and the N-terminal part of the sucrase in the final SI complex. Nucleotide and amino-acid sequences of RPSI1 were compared with their corresponding regions in rabbit pro-SI. A greater similarity was found in sucrase parts than in isomaltase parts of the two species. Northern blot analysis revealed that the mRNA levels of SI increased rapidly after sucrose force feeding, while those of rats fed a carbohydrate-free diet did not. These changes in mRNA levels correlated with the corresponding enzyme activities. The results demonstrate that the induction of SI activities is directly associated with an increase in SI mRNA levels. Our results also suggest that circadian modulation of SI transcription may occur in basic SI gene expression.

Amino Acid Sequence↗
PubMed1990

Respiratory failure and unilateral caudal brainstem infarction.

We report clinicotopographic correlations in 2 patients with central hypoventilation and unilateral infarct in the caudal brainstem. One patient had nearly complete loss of ventilation involving both automatic and voluntary components. He showed no ventilator response during a CO2 retention test (PaCO2 62 mm Hg, PaO2 82 mm Hg), while consciousness was preserved until death. The infarct involved the reticular formation, nucleus tractus solitarius, nucleus ambiguus, and nucleus retroambiguus on the right but spared the dorsal motor nucleus of the tenth cranial nerve, and sensory and corticospinal tracts. The second patient showed hypoventilation more selectively involving automatic responses (Ondine's curse). The infarct involved the medullary reticular formation and nucleus ambiguus but spared the nucleus tractus solitarius. We suggest that unilateral involvement of pontomedullary reticular formation and nucleus ambiguus is sufficient for generating loss of automatic respiration, while associated lesion of the nucleus tractus solitarius may lead to more severe respiratory failure involving both automatic and voluntary responses.

Aged↗
PubMed1990

Interlimb coordination during fictive locomotion in the thalamic cat.

Efferent discharges in muscle nerves of the four limbs were recorded simultaneously during spontaneous fictive locomotion in thalamic cats with the goal of understanding how the central nervous system controls interlimb coordination during stepping. The onset of the bursts of activity in the nerve of a selected flexor muscle in each limb allowed the temporal and the phase relationships between the fictive step cycle of a pair of limbs to be determined. Our main results are the following: 1) the fictive step cycles of the two forelimbs are always strictly alternated whereas the phasing of the step cycles of either the two hindlimbs or pairs of homolateral or diagonal limbs is more variable; 2) the time interval between the onsets of the flexor bursts of one of the two pairs of diagonal limbs is independent of the step cycle duration; 3) distinct patterns of interlimb coordination exist during fictive locomotion; a small number of patterns of coordination involving all four limbs, which correspond to the walking and the trotting gaits in the intact cat, occur very frequently. The results demonstrate that the central nervous system deprived of phasic afferent inputs from the periphery has the capacity to generate most of the patterns of interlimb coordination which occur during real locomotion. They further support the view that the central pattern of interlimb coordination essentially results from diagonal interaction between a forelimb generator for locomotion and a hindlimb one.

Afferent Pathways↗
PubMed1990

Experimental study on the fractionation schedule for proton irradiation of uveal melanoma.

Greene melanoma in the anterior chamber of rabbits was irradiated by protons to find the isoeffect curve for proton irradiation fractionated into one, two, three or four doses. The isoeffect curve for tumor tissue remained constant between one- and three-dose fractionations and rose with four-dose fractionation. The isoeffect curve for normal tissue approximately followed the Ellis equation. Therefore, the optimal irradiation schedule should be in the range of three fractions because this best spares normal tissue while delivering a tumoricidal dose to the lesion. The relative reduction of the total dose from four- to one-dose fractions of intraoperative irradiation should be 20%.

Animals↗
PubMed1990

17 beta-estradiol stimulates the calbindin-D9k (CaBP9k) gene expression at the transcriptional and posttranscriptional levels in the rat uterus.

The 9 kilodalton vitamin D-dependent calcium-binding protein (CaBP9k), calbindin-D9k, is expressed in the intestine and uterus of mammals. Rat intestinal CaBP9k is a well documented expression of the steroid hormone like action of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3). In contrast exogenous 1,25-(OH)2D3 does not affect the concentration of uterine CaBP9k which is dependent on estrogen. We have analyzed the effect of 17 beta-estradiol on the regulation of CaBP9k gene expression in the uterus of mature ovariectomized rats. CaBP9k mRNA is undetectable in the uterus of mature ovariectomized rats. A single dose of 17 beta-estradiol results in a detectable level of CaBP9k mRNA at 1 h and a significant increase 3 h after injection. The maximal CaBP9k mRNA level is reached 6 to 12 h post injection. These results show that 17 beta-estradiol increases CaBP9k production by increasing CaBP9k gene transcription. Chronic 17 beta-estradiol administration results in a plateau of CaBP9k mRNA but in a large increase in CaBP9k concentration. The kinetic response to a single estradiol injection was similar in immature rats. This result shows that no cellular differentiation is required for the control of CaBP9k gene expression by 17 beta-estradiol. The uterine cells of immature rats are already competent to respond optimally to estradiol. There is a single 0.5 kilobase CaBP9k gene transcript in the rat duodenum. In contrast there are two estrogen-inducible CaBP9k mRNA species in the uterus of both the mature ovariectomized and the immature rats. The smallest species corresponds to the duodenal CaBP9k mRNA species, while the larger species is at least 50 nucleotides larger. However, a unique CaBP9k identical to that in the duodenum is expressed in the uterus.

Animals↗