Search PubMed⌕ Search

Biomedical subjects

J Lambert

Publications and source records attributed to J Lambert.

At least 163 records · Page 9Linked to original sources
PubMed1995

Randomized trial of intake of fat, fiber, and beta carotene to prevent colorectal adenomas.

BACKGROUND: Epidemiologic evidence of associations between the high intake of fat and low intake of dietary fiber, beta carotene, and other dietary constituents and the risk of colorectal neoplasia has been inconsistent and has not provided a sufficient basis for recommendations concerning the dietary prevention of large-bowel cancer in humans. PURPOSE: We conducted a clinical trial to assess the effects on the incidence of adenomas of reducing dietary fat to 25% of total calories and supplementing the diet with 25 g of wheat bran daily and a capsule of beta carotene (20 mg daily). METHODS: We performed a randomized, partially double-blinded, placebo-controlled factorial trial in which half the patients were assigned to each intervention, resulting in seven intervention groups and one control group. Eligibility criteria included histologic confirmation of at least one colorectal adenoma and confidence expressed by the colonoscopist that all polyps had been removed. Dietary changes were individually initiated and monitored by dietitians and research nurses. At surveillance colonoscopy, the size and location of all polyps were recorded, and their histology was later centrally reviewed. Among 424 patients who were randomly assigned in the trial, 13 were found to be ineligible upon histologic review. Among the remaining 411, complete outcome data were collected from 390 at 24 months and from 306 at 48 months. All P values are from two-sided tests of statistical significance. RESULTS: There was no statistically significant prevention of total new adenomas with any of the interventions. We found a statistically non-significant reduced risk of large adenomas (> or = 10 mm) with the low-fat intervention: At 24 months, the odds ratio (OR) adjusted for potential confounders = 0.4 and 95% confidence interval (CI) = 0.1-1.1; at 48 months, OR = 0.3 and 95% CI = 0.1-1.0. Less and statistically nonsignificant reductions in the risk of large adenomas were found with wheat bran: At 24 months, OR = 0.8 and 95% CI = 0.3-2.2; at 48 months, OR = 0.8 and 95% CI = 0.3-2.5. Patients on the combined intervention of low fat and added wheat bran had zero large adenomas at both 24 and 48 months, a statistically significant finding (P = .03). CONCLUSIONS: Because only small numbers of patients were studied, our finding that the combination of fat reduction and a supplement of wheat bran reduced the incidence of large adenomas in this randomized, controlled trial must be treated with caution. The results do suggest, however, that these interventions may reduce the transition from smaller to larger adenomas, a step that may critically define those adenomas most likely to progress to malignancy.

Adenoma↗
PubMed1995

Coronary artery disease in heterozygous familial hypercholesterolemia patients with the same LDL receptor gene mutation.

BACKGROUND: Familial hypercholesterolemia (FH), an autosomal codominant disease, is characterized by high levels of LDL cholesterol and a high incidence of coronary artery disease (CAD). To date, genetic heterogeneity has hindered the proper assessment of the relation between risk factors and CAD in FH patients. METHODS AND RESULTS: We studied the association between CAD and common risk factors in a sample of 263 French Canadian FH patients (147 women, 116 men) carrying the same > 10-kb deletion of the LDL receptor gene. Thirty-five women and 54 men had CAD. The mean age of onset of CAD was 45.6 +/- 12.7 years in women and 38.8 +/- 9.4 years in men. Multiple logistic regression analyses were performed to test the association between CAD and age, tendon xanthomas, cigarette smoking, hypertension, diabetes mellitus, apolipoprotein E polymorphism, total plasma cholesterol, triglycerides, VLDL cholesterol, LDL cholesterol, HDL cholesterol, and lipoprotein(a) [Lp(a)]. In FH women, significant multivariate predictors were age (odds ratio, 1.10 for 1 year; P < .0001), VLDL cholesterol (odds ratio, 3.85 for 1 natural log unit; P < .002), and LDL cholesterol (odds ratio, 1.42 for 1 mmol/L; P < .02). In FH men, age (odds ratio, 1.08 for 1 year; P < .0001) and HDL cholesterol (odds ratio, 0.14 for 1 mmol/L; P = .05) were significant predictors of disease. Lp(a) was not a significant predictor in univariate or multivariate analyses. CONCLUSIONS: This study suggests that increased risk of CAD in FH is not solely due to elevated LDL cholesterol levels and demonstrates a sex-specific lipoprotein influence on CAD in a large sample of FH patients carrying the same LDL receptor gene defect.

Adult↗
PubMed1995

Insect immunity. The inducible antibacterial peptide diptericin carries two O-glycans necessary for biological activity.

A bacterial challenge of larvae of the dipteran insect Phormia terranovae induces the rapid synthesis of diptericin, an antibacterial polypeptide, previously characterized at the amino acid level and indirectly by cDNA cloning studies. This 82-residue polypeptide consists of an N-terminal proline-rich domain and a central and C-terminal glycine-rich domain. Using liquid chromatography coupled to electrospray ionization-mass spectrometry, we demonstrate here that this molecule is more complex than anticipated and carries two O-substitutions on threonine residues, one in the proline-rich domain (residue 10) and one in the glycine-rich domain (residue 54). These substitutions consist of identical trisaccharides: glucose-->galactose-->N-acetylgalactosamine-->(threonine). Treatment of diptericin with O-glycosidase, which selectively removes the substitutions without altering the polypeptide proper, abolishes the antibacterial activity, indicating that this posttranslational modification is essential for biological activity of the polypeptide. We also show that diptericin is posttranslationally modified by a C-terminal amidation.

Amino Acid Sequence↗
PubMed1995

Topographic EEG activations during timbre and pitch discrimination tasks using musical sounds.

Successive auditory stimulation sequences were presented binaurally to 18 young normal volunteers. Five conditions were investigated: two reference tasks, assumed to involve passive listening to couples of musical sounds, and three discrimination tasks, one dealing with pitch, and two with timbre (either with or without the attack). A symmetrical montage of 16 EEG channels was recorded for each subject across the different conditions. Two quantitative parameters of EEG activity were compared among the different sequences within five distinct frequency bands. As compared to a rest (no stimulation) condition, both passive listening conditions led to changes in primary auditory cortex areas. Both discrimination tasks for pitch and timbre led to right hemisphere EEG changes, organized in two poles: an anterior one and a posterior one. After discussing the electrophysiological aspects of this work, these results are interpreted in terms of a network including the right temporal neocortex and the right frontal lobe to maintain the acoustical information in an auditory working memory necessary to carry out the discrimination task.

Adolescent↗
PubMed1995

Disorders of auditory identification in dementia of the Alzheimer type.

Fifteen patients with probable DAT and 18 matched controls were given tests that required the identification of verbal (phonemes and words) and non verbal (sounds and melodies) stimuli. In all tests, DAT patients made significantly more errors than controls. Errors predominated in non verbal tests in both groups. DAT patients (and, to a lesser degree, control subjects) made almost exclusively acoustic errors in word-identification, while errors in the identification of sounds and melodies could be either semantic or acoustic. Some categories of errors were observed predominantly in DAT patients. These results suggest that, in addition to their cognitive impairment, DAT patients have a specific deficiency of central auditory perception.

Aged↗
PubMed1995

Food habits of French Canadians in Montreal, Quebec.

OBJECTIVES: Since the 1960's, marked sociocultural and economic changes have affected lifestyle, religious practices, and family structure among French Canadians in Quebec. Recent nutritional assessment was unavailable, despite indications of change. METHODS: A survey was carried out in 1988 in a representative sample living in Greater Montreal, to obtain current data on food habits, nutrient intakes and sociodemographic factors, using interviewer-administered questionnaires and seven-day food records. RESULTS: Some 845 families (1450 individuals from different age groups) were studied in two phases: summer/fall and winter/spring. Mean household size in the study population was 2.7. Among adults, extremes of educational level were observed, with 33% having elementary school only and 28% having completed university. On average, each household spent $CAN 89.90 a week for food, $26.00 for tobacco, and $13.50 for alcohol. Breakfast was eaten regularly by 90% of subjects while 96% ate lunch and 99% ate dinner. Morning snacks were consumed by 36% and afternoon snacks were taken by 50%. Milk was consumed with breakfast by 24% of respondents, with lunch by 19%, and with dinner by 24%. On weekdays, 81% of subjects ate their main meals at home, while on weekends this figure was 95%. Time spent for meals varied by meal, and was slightly longer on weekends. Specialty diets, including vegetarianism, were followed by 7% of the study subjects, while 22% adhered to health-related diets. CONCLUSIONS: The food record analyses revealed adequate nutrient intakes overall in relation to the 1990 Canadian Recommended Nutrient Intakes, although further investigation is needed before addressing dietary quality in specific age-sex groups. Protein comprised 16% of energy, fat 38%, and carbohydrates composed 45% or 46% for males and females, respectively. Subsequent analyses will evaluate nutrient intakes in relation to health and sociodemographic indicators in this population.

Adolescent↗
PubMed1995

Availability of 0.3% ofloxacin ointment and solution in human conjunctiva and aqueous humor.

Ofloxacin 0.3% ophthalmic solution or ointment was administered preoperatively to 13 patients undergoing cataract surgery. Mean drug concentrations in conjunctival biopsies were 2.62 and 6.55 micrograms/gm and in aqueous humor samples were 0.36 micrograms/mL and 0.43 micrograms/mL, for ointment and solution respectively. Mean conjunctival concentrations of ofloxacin achieved MIC90 values for 419 gram-positive and gram-negative organisms previously analyzed.

Aged↗
PubMed1995

A PET study of the functional neuroanatomy of writing impairment in Alzheimer's disease. The role of the left supramarginal and left angular gyri.

A dissociation in the central processes of spelling, with preferentially lexical over phonological impairment, frequently affects patients with early Alzheimer's disease. The aim of this work was to test whether dissociations in the language domain in Alzheimer's disease can be exploited with PET to assess the neural basis of cognition. To this end, we studied the functional neuroanatomy of writing impairment in Alzheimer's disease by means of PET measurements of the local cerebral glucose utilization and neuropsychological tests specially designed to assess the phonological and lexical components of writing. We analysed the performance in written spelling of irregular words and non-words of 11 right-handed patients with mild-to-moderate Alzheimer's disease. For each patient, we calculated a residual phonological score and a residual lexical score, based on a cognitive interpretation of the errors according to the item category. In each of these 11 patients, using PET, we measured the resting-state utilization of glucose in the left supramarginal gyrus and the left angular gyrus, two cortical regions selected a priori because of their presumed role in the central processes for spelling, and identified on CT scans obtained according to stereotaxic references and coregistered with PET. To assess the relationships between the neuropsychological scores and the metabolic data, we used the 'ratio paradigm', the sensitivity of which has been previously documented in cognitive-metabolic correlative PET studies of Alzheimer's disease that were less focused than the present study in both cognitive and anatomical terms. We found a highly significant positive correlation between phonological score:lexical score neuropsychological ratios and corresponding supramarginal gyrus:angular gyrus metabolic ratios. These findings further support the role of these two left-sided temporo-parietal regions in the central processes of writing and show that the neuropsychological dissociations in early Alzheimer's diseases can be exploited to further our understanding of the functional neuroanatomy of cognitive operations. The role of focal, as compared with more diffuse, brain damage in the development of impaired written language of central origin in Alzheimer's disease is also discussed.

Aged↗
PubMed1995

Effect of the inhibitor of nitric oxide synthase, NG-nitro-L-arginine methyl ester, on cerebral and myocardial blood flows during hypoxia in the awake dog.

The increase in cerebral blood flow (CBF) elicited by moderate hypoxia in anesthetized animals is little attenuated by nitric oxide (NO) synthase inhibitors. However, in previous studies, the effects of NO synthase inhibitors may have been altered by anesthetics. Consequently, we studied the effects of the NO synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), on cerebral and myocardial blood flows during hypoxia in the awake dog. Regional CBF and myocardial blood flows (MBF) were measured under normoxia and hypoxia in 16 beagle dogs after an intravenous (IV) injection of either saline (control, n = 8) or L-NAME 20 mg/kg (n = 8). One week after thoracotomy for catheter insertion, awake dogs were studied during three periods: normoxia and after 2 and 4 h of normocapanic hypoxia in an environmental chamber (FIO2 = 0.10, FICO2 = 0.035, balance N2). At each stage, a bolus injection of L-NAME or saline was followed 15 min later by left atrial injection of radiolabeled microspheres (141Ce, 103Ru, 46Sc) for regional CBF and MBF. After the dogs were killed, the brain and the heart were fixed in 10% formaldehyde, dissected by region and weighed, and radioactivity was measured in a gamma counter. During hypoxia, Pao2 was approximately 45 mm Hg with normal Paco2. In the control group, CBF increased by 45% after 2 h and 48% after 4 h of hypoxia; MBF increased by 69% and 60%, respectively. L-NAME prevented the CBF increase during hypoxia and the MBF increase after 2 h of hypoxia; after 4 h of hypoxia the measurement of MBF was confounded by cardiac dysfunction. These results suggest that NO plays a role in cerebral vasodilation during hypoxia in the awake animal.

Animals↗
PubMed1995

Vessel wall properties of large arteries in uncomplicated IDDM.

OBJECTIVE: Patients with insulin-dependent diabetes mellitus (IDDM) are at high risk for cardiovascular disease. Arterial distensibility and compliance are vessel wall properties of large arteries. Altered large artery wall properties can be an early feature of vascular dysfunction. This study investigates vessel wall properties in 30 patients with uncomplicated IDDM and 30 matched healthy control subjects. RESEARCH DESIGN AND METHODS: Vessel wall properties of the elastic common carotid (CCA) and the muscular femoral (FA) and brachial arteries (BA) were measured with a vessel wall movement detector system. Blood pressure and heart rate were recorded simultaneously with a semiautomated device. Aortic pulse wave velocity was estimated from the carotido-femoral transit time. RESULTS: Blood pressure (IDDM patients: 118 +/- 10/69 +/- 5 mmHg), pulse pressure (IDDM patients: 49 +/- 8 mmHg), and heart rate (IDDM patients: 65 +/- 9 beats/min) were similar in IDDM patients and control subjects. No statistically significant changes between IDDM patients and control subjects were found for diameter, distensibility, and compliance of the elastic CCA and the muscular BA. Distensibility (IDDM patients: 16.9 +/- 6.4 10(-3)/kPa; control subjects: 22.4 +/- 11.8 10(-3)/kPa) of the muscular FA was decreased in IDDM (P < 0.05). However, FA compliance (IDDM patients: 0.80 +/- 0.23 mm2/kPa; control subjects: 0.94 +/- 0.41 mm2/kPa) and FA diameter (IDDM patients: 7.87 +/- 1.10 mm; control subjects: 7.57 +/- 1.11 mm) did not differ statistically between IDDM patients and control subjects. Aortic pulse wave velocity was the same in IDDM patients and control subjects (IDDM patients: 5.1 +/- 0.6 m/s). No relation was found between vessel wall properties and duration of disease, actual glucose level, and HbA1c for all three arteries (CCA, BA, and FA). But the groups might have been too small to draw conclusions. CONCLUSIONS: The results of the present study show that in this group of patients with uncomplicated IDDM, vessel wall properties of elastic and muscular large arteries were not obviously reduced when compared with healthy control subjects. However, distensibility of the FA was lower in IDDM patients. Early atherosclerotic changes in IDDM frequently occur at this site. A difference related to the duration of diabetes could not be excluded.

Adolescent↗
PubMed1995

Utility of measurement of gentamicin release from PMMA beads in wound drainage fluid after in-vivo implantation.

Acute or chronic osteomyelitis in 188 patients was treated by surgical debridement and filling of the cavity with gentamicin-PMMA beads. The gentamicin concentration was measured in the total drainage fluid of the first postoperative day. There was no correlation between this concentration and the amount of implanted beads. It is impossible to predict preoperatively the gentamicin concentration which will be obtained in situ. The measurement of gentamicin concentration in the total drainage fluid of the first postoperative day and its comparison to the minimal bactericidal concentration of responsible pathogens, allow very early assessment of the effectiveness of the local antibiotherapy and if necessary, adaptation, of systemic antibiotherapy.

Exudates and Transudates↗
PubMed1995

Gastric acid-related disorders: GORD and peptic ulcer disease.

Gastro-oesophageal reflux disease (GORD) and peptic ulcer disease share similar clinical features, both have a high prevalence in the Australian community and both are associated with gastric acid secretion. In recent years there has been a considerable improvement in understanding of the pathogenesis of these conditions, leading to more effective therapy. The management of these disorders with particular reference to general practice will be reviewed.

Adult↗
PubMed1994

Purification and in vitro activity of a truncated form of ANFA. Transcriptional activator protein of alternative nitrogenase from Azotobacter vinelandii.

The ANFA protein is the transcriptional activator of the sigma 54-dependent anfHDGK operon, which codes for the structural genes of the third nitrogenase system in Azotobacter vinelandii. We have purified, in soluble active form, an N-terminally truncated form of the protein, delta ANFA, which activates transcription from the anfH promoter and other sigma 54-dependent promoters in a purified transcription system. Sequences upstream of the anfH promoter and the presence of the integration host factor protein stimulate transcription, and we have shown that delta ANFA binds to sites situated between 200 and 300 base pairs upstream of the anfH promoter. In common with other sigma 54-dependent activators, ANFA has a highly conserved ATP binding motif in its central domain, and we have demonstrated that ATP or GTP is required for productive complex formation and that the purified truncated protein has a constitutive ATPase activity, which is presumably required to drive open complex formation.

Adenosine Triphosphatases↗
PubMed1994

Midwifery defined by physicians, nurses and midwives: the birth of a consensus?

OBJECTIVE: To describe the form of midwifery practice preferred by physicians practising obstetrics, nurses providing maternity care and midwives. DESIGN: Mail survey conducted in 1991. SETTING: Province of Quebec. PARTICIPANTS: A systematic random sample of 844 physicians, 808 nurses and 92 midwives; 597, 723 and 92 respectively completed the questionnaire, for an overall response rate of 80%. MAIN OUTCOME MEASURES: Midwife training options, range of responsibilities, location of midwifery care, relationship to other maternity care providers and degree of autonomy. RESULTS: Most of the physicians, nurses and midwives surveyed agreed that if midwifery was legalized, midwives should have a university degree, provide basic care to women with normal pregnancy and delivery, provide prenatal and postnatal care in hospitals and community health centres, perform delivery in hospitals and work in close collaboration with the other maternity care professionals. Disagreement existed concerning the level of university training required, the need for training in nursing first, the scope of medical intervention performed by midwives, out-of-hospital delivery, the autonomy of midwives and control over their practice. CONCLUSION: Some consensus on midwifery practice exists between physicians, nurses and midwives. In jurisdictions where opposition to midwives is strong, such consensus could serve as the starting point for the introduction of midwifery.

Attitude of Health Personnel↗