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Biomedical subjects

N Fontaine

Publications and source records attributed to N Fontaine.

At least 19 recordsLinked to original sources
PubMed2001

Diabetes Screening in Canada (DIASCAN) Study: prevalence of undiagnosed diabetes and glucose intolerance in family physician offices.

OBJECTIVE: To assess the prevalence of undiagnosed diabetes and glucose intolerance in individuals > or =40 years of age who contacted their family physician for routine care. RESEARCH DESIGN AND METHODS: The study used a stratified randomized selection of family physicians across Canada that was proportional to provincial and urban/rural populations based on Statistics Canada Census data (1996). Consecutive patients > or =40 years of age were screened for diabetes. If a casual fingerprick blood glucose was >5.5 mmol/l, the patient returned for a fasting venous blood glucose test. If the fasting blood glucose was 6.1-6.9 mmol/l, a 2-h 75-g post-glucose load venous blood glucose was obtained. Results of these tests were used to classify patients in diagnostic categories. RESULTS: Data were available for 9,042 patients. Previously undiagnosed diabetes was discovered in 2.2% of the patients, and new glucose intolerance was found in an additional 3.5% of patients. Overall, 16.4% of patients had previously known diabetes. The decrease in fasting plasma glucose criterion from 7.8 to 7.0 mmol/l resulted in a 2.2% versus a 1.6% prevalence of new diabetes. Several risk factors were reported in a significantly greater proportion of patients with new glucose intolerance and either new and known diabetes compared with the normal glucose tolerance group of patients. CONCLUSIONS: Routine screening for diabetes by family physicians is justified in patients > or =40 years of age, given the finding of previously undiagnosed diabetes in 2.2% of these patients and newly diagnosed glucose intolerance in an additional 3.5% of these patients. Another 16.4% of primary care patients > or =40 years of age have known diabetes. This has important implications regarding health resources and physician education.

Adult↗
PubMed2000

Contrast and glare testing in the assessment of visual performance of candidate eyes for penetrating keratoplasty.

PURPOSE: To determine whether visual acuity (VA) measurements performed at low levels of contrast and glare are a better diagnostic tool for determining whether corneal clouding warrants surgery. METHODS: Fifty-nine subjects were recruited from among the candidates for corneal graft. Monocular VA was measured with three Regan contrast VA charts: 96, 25, and 11%, with and without glare provided by the Brightness Acuity Tester (BAT). The discriminative ability of the tests was estimated using the area (AR) under receiver operating characteristic (ROC) curves. Associations between the different VA tests and the Visual Function Index (VF-14) score were studied, using Spearman coefficients. RESULTS: When comparing candidate eyes with contralateral eyes with corneal disease, lower contrasts VA tests provided greater discriminative power. VA measurements made with glare also tended to provide greater discrimination. In fact, discrimination was best with 11% contrast VA with glare, but "testability" was poor. The most practical test in a clinical setting, which retained high discriminative ability (0.798), was the 25% contrast VA with glare. The eye with the best VA correlated strongly with the VF-14, especially at 25% contrast without glare, resulting in an Rs of -0.729. CONCLUSION: Twenty-five percent contrast VA with BAT could help the practitioner to decide whether a corneal transplant is warranted when symptoms of reduced vision are more important than what high-contrast VA might indicate.

Adult↗
PubMed1999

The VF-14 index of functional visual impairment in candidates for a corneal graft.

PURPOSE: To validate the Visual Function-14 (VF-14) index of functional visual impairment in candidates for a corneal graft. METHODS: One hundred thirty-four patients who were candidates for a corneal graft participated in this study between August 1996 and February 1997. Demographic, ocular history, best-corrected visual acuity, and detailed ocular examination data were collected. Functional visual impairment information was obtained by telephone interviews using the following: VF-14, SF-36 (Short Form-36, a more generic measure of general health function), and Visual Symptom Score, and four questions measuring the overall amount of trouble with vision, dissatisfaction with vision, ocular pain, and discomfort. RESULTS: The average age of corneal graft candidates was 64 +/- 18 years (range, 18 to 90 years) and 60% were women. The most frequent corneal disease was pseudophakic bullous keratopathy (41%). Ocular comorbidities included glaucoma or ocular hypertension (30%) and cataract (19%). The mean best-corrected visual acuity of the eye scheduled for surgery was 1.33 +/- 0.56 logMAR whereas the best eye best-corrected visual acuity was 0.36 +/- 0.44 logMAR. The mean VF-14 score was 73% +/- 26%, and the internal consistency was high, with a Cronbach alpha value of 0.94. The VF-14 correlated strongly with the best eye best-corrected visual acuity. It also correlated strongly with the Visual Symptom Score, the global measures of trouble and dissatisfaction with vision. Candidates for a corneal graft had low scores for all eight general health concepts evaluated with the SF-36, and the VF-14 correlated with seven of the eight SF-36 subscales. CONCLUSION: The VF-14 is a valid measure of functional visual impairment in candidates for a corneal graft. The Visual Symptom Score and the SF-36 are also useful indices in such patients.

Adolescent↗
PubMed1999

Variation of mucin distribution in the rat intestine, caecum and colon: effect of the bacterial flora.

The influence of the intestinal microflora on mucin types was studied in the small intestine, caecum and colon of conventional (CV) rats as compared to germ-free (GF) rats. A colorimetric method was used on purified water-soluble mucin extracted from mucosal scrapings and contents. Variations occurred between the three anatomical sites both in the mucosas and intestinal contents of GF rats. In CV rats, the presence of the bacterial flora led to different effects depending on the intestinal site: in the small intestinal mucosa, neutral and sulphomucins values were higher whereas sialomucin was much lower. Conversely, sialomucin was higher in the caecal and colonic mucosas and contents whereas sulphated mucins were decreased significantly in caecal contents and caecal and colonic mucosas. These variations in the contents may reflect the bacterial mucolytic activity and the effect of bacterial metabolites on the mucosa.

Animal Feed↗
PubMed1997

Anaesthetic management of caesarean section in a parturient with acute myelodysplastic syndrome.

A 34-year-old pregnant woman developed a myelodysplastic syndrome during pregnancy which resulted in a refractory anaemia and an extreme thrombocytopenia. The report describes the anaesthetic management of elective caesarean section and successful childbirth in this patient. Following replacement therapy with packed red cells and platelets, general anaesthesia was used for the procedure.

Journal Article↗
PubMed1997

Optical performance of aspheric concave ophthalmic lenses: the effect of vertex distance.

Variations of power errors in the periphery of concave aspheric lenses were assessed as a function of vertex distance. Comparisons were made between the performance of different types of spherical lenses and that of aspheric lenses (-6.00 and -8.00 D lenses were used). Off-axis measurements were made by means of a modified focimeter, which enabled rotation of the lens around the center of the vertex sphere. Reduction of the vertex sphere's radius from 27 to 23 mm simulated a 4-mm decrease in vertex distance. Results of the measurements are compared with a computed model. These results indicate that off-axis performance is more affected by a reduction of vertex distance in the case of aspheric lenses compared to spherical lenses. Resulting increases in oblique astigmatism (OA) and mean oblique error (MOE) are at the limit of clinical acceptance. The importance, for the practitioner, of respecting the vertex distance selected for a specific aspheric design when fitting this type of lens is emphasized.

Computer Graphics↗
PubMed1996

Intestinal mucin distribution in the germ-free rat and in the heteroxenic rat harbouring a human bacterial flora: effect of inulin in the diet.

A colorimetric method was used on water-soluble mucin extracted from mucosal scrapings and contents of the caecum and the colon of five germ-free (GF) rats and five heteroxenic (HE) rats harbouring a human flora (GF rats associated with a human flora). These rats were fed on a diet containing either 100 g sucrose/kg or 100 g inulin/kg. Histological stains, periodic acid-Schiff, alcian blue pH 2.5 and alcian blue pH 0.5 were used to discriminate between neutral, acidic and acidic sulphated mucins respectively. Spectrocolorimetric assays led to a calculated absorbance value for 1 mg of the initial mucin extract. Each mucin type was compared between treatments. The caecal contents of GF rats contained more acidic mucin than sulphomucin, which was present in the same proportion as neutral mucin. Their colonic contents contained more acidic mucins than sulphomucin, which in turn was more abundant than neutral mucin. Their caecal mucosa mucin distribution differed from that of the contents: very little acidic mucin was present and neutral and sulphomucin proportions were of the same order of magnitude. Inulin increased the amount of neutral mucin in the caecal contents and of sulphated mucins in the colonic contents and increased the amounts of neutral and acidic mucins in the caecal mucosa. Mucin distribution in the HE rats was very different from that in the GF rats: the caecal contents contained a high proportion of acidic mucins and very little sulphomucin. The same distribution of mucins was observed in the colonic contents. The caecal mucosa contained less acidic mucin and more sulphomucin than the caecal contents. Inulin decreased acidic mucins and increased sulphated mucins in the caecal contents and increased neutral and sulphated mucins in the colonic contents. Inulin increased sulphomucin in the caecal mucosa and decreased acidic mucin in the caecal and colonic mucosas. The very low amount of mucin that was recovered in the colonic mucosa suggests that, in the presence of the bacterial flora and associated with inulin in the diet, mucin was extensively released from the mucosa to the colonic lumen. This might be related to the bacterial metabolites produced.

Animals↗
PubMed1994

[Selective determination of different types of gastrointestinal mucins:use of histochemical reagents].

A method, transposed from the mucin histochemical stainings, was proposed to evaluate neutral, acidic and sulphated mucins by spectrocolorimetry. Stainings used were periodic acid/Schiff (PAS), Alcian blue (AB) pH 2.5, and Alcian blue (AB) pH 0.5. Mucin samples were extracted from mucosal scrapings, from intestinal contents of germ-free rats or from commercial pig gastric mucin. A mucin-enriched fraction was obtained and lyophilised and the protein content was determined. Each mucin type was spectrophotometrically analysed after staining and precipitation by slightly modified Carnoy fixative. The histochemical stainings used here, after modification by Carnoy fixative treatment, were, as shown by electrophoretic controls, specific for mucin types contained in these mucins without protein contaminant interference.

Alcian Blue↗
PubMed1987

Importance of cereal phytase activity for phytate phosphorus utilization by growing pigs fed diets containing triticale or corn.

In contrast to corn, wheat and triticale exhibit high phytase activities. This enzyme enhances phytic phosphorus availability, as demonstrated in pigs given wheat diets. To study the utilization of triticale phosphorus in pigs, the importance of dietary phytase content and the mineral and bone disorders related to high phytate feeding, a nutritional experiment was carried out in 12 growing pigs fed either a corn- or a triticale-based diet for 6 wk. The diets were almost identical except for the cereal component; their phosphorus contents were low (0.4%) and mainly phytic. The following parameters were measured: calcium and phosphorus balances, bone and plasma contents of calcium and phosphorus, plasma vitamin D metabolites and parathyroid hormone (PTH), bone bending moments and intestinal phosphatase activities. Both diets provoked a phosphorus deficiency, but hypophosphatemia occurred less rapidly, hypercalciuria and hypophosphaturia were less marked and phosphorus availability was greater when the triticale diet was fed. This was attributed to the high phytase content of triticale because intestinal phytase and alkaline phosphatase activities were similar in pigs fed either diet. Calcium absorption was not modified by calcium retention was greater for pigs fed triticale and led to higher bone scores. In conclusion, the higher the phytase activity of the diet, the greater the phytate P availability and the lower the bone-mineral disorders.

6-Phytase↗
PubMed1986

Effects of vitamin D on calcium regulation in vitamin-D-deficient pigs given a phytate-phosphorus diet.

1. Vitamin-D-deficient pigs were fed on a phytate-phosphorus diet and treated with vitamin D3 (+D) to examine the time-course of adaptative changes in plasma minerals, vitamin D metabolites, parathyroid hormone (PTH) and calcium balance and intestinal Ca-binding protein (CaBP). 2. The 5-week vitamin D repletion (25 micrograms cholecalciferol/kg diet) regimen restored plasma Ca, P and alkaline phosphatase (EC 3.1.3.1) to normal, decreased PTH and markedly and rapidly increased plasma 25-hydroxycholecalciferol (25-OHD, sevenfold after 4 d) and 1,25-dihydroxycholecalciferol (1, 25(OH)2D3, 1.8-fold after 4 d). 3. CaBP concentrations were markedly elevated all along the digestive tract, especially in the distal regions. 4. Ca absorption and retention were enhanced (fourfold and sixfold respectively) by the +D diet. 5. The improved Ca absorption, coupled with increased CaBP and 1,25(OH)2D3 levels, suggest that vitamin D metabolism in phytate-P-fed pigs is sensitive to the depressed Ca availability due to phytate feeding. It also indicates that CaBP may play an important role in the adaptation of Ca absorption. 6. Persistent hypercalciuria indicates that mineral metabolism was still affected by the phytate nature of the dietary P in spite of the vitamin D treatment.

Alkaline Phosphatase↗
PubMed1986

[Elsewhere and otherwise.].

The network of mental health services is constantly in movement. From a relatively simple model it has become a complex service with a multiple ideology, its results are indetermined and have now to be revised. While commenting on the elaboration of a politic in mental health, the authors describe an experience where the mental health services in a Montreal region were diversified and reorganised in sub-regions. They then give an idea of the situation, the arms hoped for, the organisational mode, and the sub-regions; the main problems encountered are identified as well as the stakes and the areas of action. They uncover the particularities and the different realities that are the mainstay of the Greater Montreal.

English Abstract↗
PubMed1985

[Absence of effect of vitamin D on intestinal phytase and alkaline phosphatase: relation with phytic phosphorus in the pig].

At least two-thirds of the phosphorus ingested by pigs is in the form of phytates. Two intestinal vitamin D-sensitive enzymes, alkaline phosphatase and phytase, might be involved in phytate-P digestion. The effects of dietary vitamin D upon the two intestinal phosphatases and P utilization in pigs fed a high phytate-P diet are reported here. Fourteen vit. D-depleted pigs (25-hydroxy vit. D: about 2 ng/ml plasma) were divided into two groups fed the same basal diet containing 0.6% P (of which 80% was phytic) and 0.6% Ca. One group (+D) was supplemented for 5 weeks with vit. D (1 000 IU D3/kg diet) and the other (-D) received none. P absorption and retention was two times higher in +D pigs than in -D animals (balance technique), and tibia X-ray pictures showed a lower bone density with the -D diet than with the +D diet. Surprisingly, vit. D supplementation had no effect on either of the mucosal enzymes (phytase and alkaline phosphatase). It may be concluded that vit. D improves phytate-P absorption via a mechanism which does not involve an increase in the activity of the intestinal phosphatases.

6-Phytase↗
PubMed1985

[Comparative effects of magnesium deficiency and overload on calcium and phosphorus metabolism in the growing pig].

This study was designed to assess the influence of dietary magnesium on calcium and phosphorus metabolism in growing pigs. 18 4-month-old pigs received either an Mg-deficient (40 ppm), an Mg overload (5,600 ppm) or a control Mg diet (1,000 ppm) for 70 days. The following parameters were measured: kinetics of plasma concentrations of Ca, phosphates, Mg and alkaline phosphatase (AP), absorptions, urinary and fecal excretions, retentions of Ca, P and Mg, soft tissue and bone mineral contents (BMC), and intestinal mucosal CaBP (calcium-binding protein) and AP activities. Dietary Mg level had no effect on calcium and phosphorus metabolism as far as Ca and P absorptions and retentions, BMC, intestinal CaBP and plasma levels of Ca, P and AP are concerned. Mg overload significantly decreased urinary P excretion and increased kidney P content, but did not change fecal P excretion. Jejunal AP activity was slightly decreased in Mg-deficient pigs. The plasma, bone, urinary, fecal, absorbed and retained Mg varied linearly with Mg intake (r: 0,85-0.96). In Mg-deficient pigs, hypomagnesemia appeared after 1 week and its severity did not increase with time. In Mg-overloaded pigs, hypermagnesemia occurred very late and was limited. This suggests that, in the growing pig, dietary Mg has little or no effect on Ca-P metabolism. It may also be concluded that growing pigs are rather resistant to Mg deficiency since no clinical symptoms were observed.

Alkaline Phosphatase↗
PubMed1977

[Effect of sorbitol on the activity of alkaline phosphatases isolated from different areas of rat small intestine].

To elucidate by which way sorbitol (S) increases Ca absorption, the action of (S) on the alkaline phosphatases (A.P.) isolated from duodenum, jejunum and ileum of the young rat is studied. At pH = 9,8 A. P activation by (S) is the most pronounced with ileal A.P. At each studied pH (greater than or equal to 8) the ability of A. P to phosphorylate (S) is observed constantly. A diffusional system transfer of Ca is proposed involving the intervention of a A. P under the inhibiting control of phosphates. This inhibition would be suppressed by the A. P transphosphorylating action toward (S).

Alkaline Phosphatase↗
PubMed1977

[Strong increase in hepatic and blood histamine levels after partial hepatectomy in rats].

The histamine rates, when established by fluorometry, according to the method of Shore, in the residual liver and in the whole blood of Wistar-Commentry male rats, quickly increase after partial hepatectomy carried out as described by Higgins and Anderson. The levels reach a peak 24 h after hepatectomy, then progressively lower, and on the 4th day are almost equal to the rates of control or sham operated animals.

Animals↗
PubMed1977

[Effects of tritoqualine on hepatic and blood levels of histamine after partial hepatectomy in rats].

Looked as a specific inhibitor of histidin-decarboxylase, tritoqualine has been injected subcutaneously to Wistar rats immediately after partial hepatectomy and, then, once in 24 hours until 72 hours. It has thus provoked : an unexpected, but transient rise (reaching its apex 3 hours after the operation) of the hepatic and blood histamin concentrations ; then, the expected decrease (more durable and greatest at 48 hours) of the same concentrations. Therefore, an effect of tritoqualine on the liver regeneration might be expected, whether histamin plays some part in this phenomenon.

Animals↗