Biomedical subjects

C Morin

Publications and source records attributed to C Morin.

At least 37 records · Page 2Linked to original sources

PubMed2001

Cortical activation by tactile and painful stimuli in hemispherectomized patients.

Hemispherectomized patients are able to perceive tactile and painful stimuli on their nonparetic as well as paretic body halves. We have used functional MRI to study the cortical mechanisms underlying this preserved somatosensory capacity. Nonpainful brushing and painful heat were applied to the skin of the legs in four hemispherectomized patients and, for comparison, in four normal subjects. Cortical activation was studied with a 1.5 T scanner using a BOLD (blood oxygen level dependent) protocol. All patients rated both the brushing and the heat pain as almost equally intense on each leg and the ratings were similar to those in normals. Brushing on the nonparetic leg activated primary and secondary somatosensory cortices (S1 and S2) in all patients, similar to findings in normals. Brushing on the paretic leg activated S1 in two patients and S2 in one of these patients. Heat pain activated S2, insular cortex and anterior cingulate cortex to a similar degree for both legs, but the activation was weaker in the patients than in the normals. For the individual patient, there was generally no obvious correlation between cortical activation as studied with the BOLD technique and psychophysical performance. The findings from tactile stimulation of the nonparetic leg, that the activation was similar to the contralateral activation in normals, suggest that tactile information processing in the hemisphere contralateral to the stimulation is independent of the corpus callosum. In contrast, the pain activation for the nonparetic leg was weaker than in normals, suggesting that pain activation in the hemisphere contralateral to the stimulation is dependent on transcallosal information processing. The latter finding was corroborated by a subnormal capacity for pain localization on the nonparetic foot in two of the patients. The findings from stimulation of the paretic leg show that areas typically involved in the processing of tactile and painful stimuli can be activated by ipsilateral pathways directly from the periphery. The tactile-evoked ipsilateral S1 activation may be due to subcortical reorganization, since it was not observed in the normal subjects.

Adult↗

PubMed2001

Evaluation of a modified sanitary napkin as a sample self-collection device for the detection of genital chlamydial infection in women.

A modified sanitary napkin was compared with endocervical swab and urine specimens for the detection of urogenital Chlamydia trachomatis infection. Endocervical swabs and/or first-catch urine were collected from 510 women at medical or community settings in Quebec City. Participants were also asked to wear a modified sanitary napkin (Ezy-Detek) during 4 consecutive hours and to bring it back to the clinic or mail it to the laboratory. Endocervical and urine specimens were tested using the Cobas Amplicor CT/NG assay (Roche Diagnostic Systems) according to the manufacturer's instructions, as were specimens collected with the napkin after adequate preparation. If the PCR test result was positive on the endocervical sample or on any two samples, a woman was considered to be infected. PCR testing results on paired samples were identical for 493 (96.6%) of 510 women. According to the definition given above, 58 (11.3%; 95% confidence interval [CI], 8.7 to 14.5%) women were infected with C. trachomatis. The sensitivity and specificity of PCR testing on modified sanitary napkin specimens were, respectively, 93.1% (54 of 58; 95% CI, 83.3 to 98.1%) and 98.9% (447 of 452; 95% CI, 97.4 to 99.6%) compared to 81.0% (47 of 58; 95% CI, 68.6 to 90.1%) and 100% (451 of 451; 95% CI, 99.2 to 100%) for urine specimens. The positive and negative predictive values were, respectively, 91.5% (54 of 59) and 99.1% (447 of 451) for the sanitary napkin specimens compared to 100% (47 of 47) and 97.6% (451 of 462) for urine samples. These results suggest that a modified sanitary napkin represents an effective noninvasive device for self-collection of specimens to detect urogenital C. trachomatis infection.

Adolescent↗

PubMed2001

Managing atypical squamous cells of undetermined significance in Papanicolaou smears.

OBJECTIVE: To assess strategies using repeated conventional Pap smear and human papillomavirus (HPV) DNA testing, alone or in combination, for identifying women with concomitant cervical intraepithelial neoplasia 2 and 3 (CIN 2/3) in women with atypical squamous cells of undetermined significance (ASCUS) in their Pap smears. STUDY DESIGN: A total of 360 women cytologically diagnosed with ASCUS were referred for colposcopy and underwent a repeat Pap smear, a biopsy when necessary and HPV testing using three different modes of detection of high-oncogenic-risk HPV types: 1, first-generation Hybrid Capture test (HC-1) (Digene Diagnostics, Gaithersburg, Maryland); 2, second-generation Hybrid Capture test (HC-2); and 3, polymerase chain reaction (PCR). RESULTS: Nineteen patients (5.3%) had histologic CIN 2/3. The sensitivity and specificity of the repeat Pap smear alone for the detection of CIN 2/3 were 73.7% and 62.9%, respectively, when referring all women with a repeat Pap smear using an ASCUS-positive threshold. The proportion of women referred for colposcopy was 39.0%. When HPV testing for high risk was used for identification of women with histologic CIN 2/3, sensitivity and specificity were, respectively, 68.4% and 85.9% for HC-1, 89.5% and 73.9% for HC-2 and 89.5% and 59.0% for PCR. The rate of referral for colposcopy of these three modes of HPV testing was 16.9%, 29.4% and 44.0%, respectively. The sensitivity and specificity for identification of women with concomitant CIN 2/3 using a combination of repeat cytology showing a low grade squamous intraepithelial lesion or high grade squamous intraepithelial lesion and/or a test positive for high-oncogenic-risk HPV group were, respectively, 94.7% and 73.2% when used in combination with HC-2. The referral rate of women for colposcopy of this combined strategy was 30.4%. CONCLUSION: As compared to the strategy using abnormal repeat Pap smear alone, those using high-risk HPV testing with Hybrid Capture showed statistically significantly higher specificities and lower proportions of women with ASCUS referred for colposcopy. In particular, a promising strategy would be to refer for colposcopy only women with repeat Pap smears showing squamous intraepithelial lesion and/or those positive for high-risk HPV detected by Hybrid Capture testing.

Adolescent↗

PubMed2000

Pain expression and stimulus localisation in individuals with Down's syndrome.

BACKGROUND: Individuals with Down's syndrome do not always exhibit signs of distress in reaction to noxious stimuli comparable with the general population. This pilot study was designed to measure the ability of individuals with Down's syndrome to detect and express sensation in comparison with healthy volunteers. METHODS: In the first test, the latency of pain detection to self-administered cold stimuli on the wrist and on the temple was measured. The second test was designed to assess ability to localise cold stimuli on sites on the hand, on the face, and in the mouth. FINDINGS: 75 control individuals and 26 individuals with Down's syndrome were tested. Individuals with Down's syndrome had significantly longer median latencies than controls: Down's syndrome median (quartiles) 28.7 s (1st 18.0, 3rd 47.6); controls 20.6 s (1st 12.4, 3rd 31.0); p=0.0005. In addition, more individuals with Down's syndrome had difficulties in localising the cold stimulus. The differences in distribution for precise localisation were significant for the hand (Down's syndrome [p<0.0005] 54%; control 99%), the mouth (31%; 84%), and the face (54%; 97%). INTERPRETATION: Individuals with Down's syndrome are not insensitive to pain. However, they do express pain or discomfort more slowly and less precisely than the general population. This implies that medical teams managing these patients should use pain-control procedures, even in the absence of obvious pain manifestations.

Adolescent↗

PubMed2000

Human papillomaviruses and vulvar vestibulitis.

OBJECTIVE: To assess the relationship between human papillomavirus (HPV) infection and vulvar vestibulitis syndrome. METHODS: From November 1995 to December 1997, 135 women with vulvar vestibulitis were compared with 322 controls who had no evidence of vulvar vestibulitis. Human papillomavirus DNA was amplified by polymerase chain reaction and detected with liquid-capture molecular assay. RESULTS: Human papillomavirus DNA was found in 29.6% of cases and in 23.9% of controls (relative risk [RR] 1.4; 95% confidence interval [CI].8, 2.2). The prevalence of HPV tended to decrease with increasing duration of pain among cases. Thus, prevalences were 37. 5%, 29.6%, and 22.0% for pain durations of 3-6 months, 7-12 months, and 13-24 months, respectively (P =.14). Prevalence of HPV also tended to increase with pain intensity among cases, but that association was not statistically significant (P =.57). Prevalence percentages for women with low, moderate, or severe pain were 27.5%, 28.8%, and 34.4%, respectively. Prevalence of HPV was slightly higher in cases with the most severe pain (34.4%) than in controls (23.9%) (RR 1.8; 95% CI.8, 4.0). In cases with the most pain in the shortest time (3-6 months), prevalence of HPV was double that of controls (50% versus 23.9%) (RR 3.5; 95% CI 1.0, 12.7; P =.054). CONCLUSION: There was little support for the idea that HPV might be related to vulvar vestibulitis.

Adult↗

PubMed2000

Differences between the sexes in post-surgical pain.

It has been shown that women have a lower pain threshold and lower tolerance to some forms of experimental pain then men. However, the evidence that clinical pain is perceived differently by the two sexes is not yet as strong. The placement of intraoral implants is a highly controlled surgical procedure that we have used to investigate this possibility. Forty-eight edentulous (without teeth) subjects (27 females), aged from 35 to 63 years, received two titanium implants in the anterior mandible under local anesthesia. After the surgery, subjects completed a pain diary three times each day, rating pain intensity and unpleasantness on 100 mm visual analog scales (VAS). Once a day, they chose verbal descriptors from the McGill Pain Questionnaire (MPQ). Age of subjects, duration of surgery, the amount of local anesthetic used and the amount of pain medication taken were not statistically different for the two groups (P>/=0.32). Results showed that the senior surgeon produced significantly less pain than a 4th year resident (P=0.04). Although there were no significant differences between sexes for mean daily ratings of intensity or unpleasantness over time (P>/=0.10), most women experienced the highest intensity of pain during the day, while most men had higher pain in the evening (P=0.025). Also, the relative unpleasantness (unpleasantness/intensity ratio) increased significantly with time for males, but not for females (P=0.016). Males and females did not differ in the total number of words chosen from the MPQ (P=0.61), or in the averaged Pain Rating Index (PRI) (P=0.53). However, women used significantly more evaluative words than men (P=0.04), suggesting that woman found the overall intensity greater. These results indicate that women find post-surgical pain more intense than males, but that men are more disturbed than women by low levels of pain that last several days.

Adult↗

PubMed2000

Synthesis and evaluation of fructose analogues as inhibitors of the D-fructose transporter GLUT5.

We have examined the specificity and binding-site spatial requirements of the fructose transporter GLUT5. Interaction with a series of fructofuranosides and fructopyranosides suggests that both furanose and pyranose ring forms of D-fructose combine with GLUT5. The epimers of D-fructose all have low affinity for GLUT5 suggesting that the transporter requires all hydroxyls to be in the fructo-configuration. Similarly there is poor tolerance of all allyl derivatives of D-fructose except 6-O-allyl-D-fructofuranose. Therefore, the C-6 position offers the most suitable position for development of affinity probes and labels for exploring GLUT5 biochemistry.

Animals↗

PubMed2000

Syntheses of R and S isomers of AF-DX 384, a selective antagonist of muscarinic M2 receptors.

Enantiomers of 5,11-dihydro-11-[2-[2-[(N,N-dipropylaminomethyl)piperidin-1- yl]ethylamino]-carbonyl]-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one (AF-DX 384) 1, have been synthesized from (S)-(+) and (R)-(-)-2-[N,N-dipropylaminomethyl]piperidine 4. The enantiomeric excess of 1 has been determined by capillary electrophoresis by using the alpha-highly sulphated cyclodextrin (alpha-HSCD) as chiral selector within the running electrolyte. (S)-(+)-(4) was prepared from (S)-(-)-pipecolic acid in a 4-step procedure (overall yield: 30%, ee: 99%) and (R)-(-)-AF-DX 384 from (R)-(+)-pipecolic acid. The (R)-(-) isomer exhibited in vitro a 23-fold higher affinity than its enantiomer (S)-(+) towards muscarinic receptors of subtype 2.

Animals↗

PubMed2000

Comparative study of the in vitro characteristics of osteoblasts from paralytic and non-paralytic children.

STUDY DESIGN: Cerebral palsy is known to provoke a high loss of bone in children and adults. The potential interest of human osteoblastic cell culture for assessing the osteoblastic function in metabolic bone disorders has been demonstrated by many previous studies. Few studies have attempted to evaluate the capacities of osteoblasts isolated from immobilized or normal bones by in vitro culture methods. Moreover, a few teams did make the distinction between young spastic and flaccid patients. OBJECTIVES: We attempted to characterize mature osteoblasts (OB) and bone marrow-stromal cells (BM) originating from 56 immobile and normal children. Spastic and flaccid patients formed the paralytic group. SETTING: France. METHODS: Osteoblasts and bone marrow cells were isolated from iliac crests obtained during pelvic osteotomies of young control and paralytic patients. The in vitro viability, proliferation and differentiation parameters of the cells from paralytic patients were compared with those of cells coming from normal controls. RESULTS: No significant differences in the cell proliferation parameters were observed between the two groups. Only initial cell viability before inoculation was lower for the paralytic group, compared to the control group. On the other hand, contrary to expectations, we found that fresh and thawed OB cells from flaccid patients synthesized more osteocalcin and more collagen respectively than those of the spastic and control groups. Opposite results were obtained from BM cultures. CONCLUSION: A negative feedback mechanism by systemic or local factors, which is not conserved in vitro but controls the in vivo osteocalcin and collagen synthesis of flaccid paralytic OB cells, is hypothesized. Because these flaccid patients are known to have a high fat/lean mass, we suggest that leptin may be the potential regulating factor implicated in the hypothesized negative feedback mechanism.

Bone Marrow Cells↗

PubMed1999

On the analogy between forskolin and D-glucose.

2-O-Acetyl-D-glucose was synthesized in order to evaluate the influence of an acyl group on the binding with the glucose carrier protein (GluT); as its affinity neighbours that of glucose itself, the glucose-forskolin analogy appears to be coincidental and several explanations are proposed.

Adipocytes↗

PubMed1999

Design and synthesis of a redox-active Tc-99m radiopharmaceutical with ferrocenedithiocarboxylate [FcCS = Fe(C5H4CS2)(C5H5)-].

The synthesis, at tracer level, of two Tc-99m complexes having the same chemical composition and structure, but differing by one electron in the total electron counting, is reported. These compounds have been prepared by reacting [99mTcO4]- with the piperidinium salt of the ligand ferrocenedithiocarboxylate {[Fe(II)(C5H4CS2)(C5H5)]- = FcCS}, in the presence of N-methyl S-methyldithiocarbazate as donor of N3-groups, and triphenylphosphine or SnCl2 as reducing agents. The formation of the neutral complex [99mTc(N)(FcCS)2] (compound A) and of the monocationic, mixed-valence complex [99mTc(N)(FcCS) (FcCS)]+ (compound B) {FcCS = [Fe(III)(C5H4CS2)(C5H5)]} was obtained in high yield. Both complexes comprise a terminal Tc triple bond N multiple bond and two FcCS ligands coordinated to the metal center through the two sulfur atoms of the -CS2 group, but they differ in the oxidation state of one of the two iron atoms of the coordinated FcCS ligands. In complex A, the two Fe atoms are both in the +2 oxidation state, while in B, one Fe atom is in the +2 and the other is in the +3 oxidation state. Thus, B is a mixed-valence Fe(II)-Fe(III) complex. B is easily converted into A by one-electron exchange with various reductants such as triphenylphosphine and excess SnCl2. Biodistribution studies in rats showed that complexes A and B are mostly retained in lungs and liver without any significant uptake in organs such as heart and brain.

Animals↗

PubMed1999

Differential effects of morphine on pain and temperature perception in human volunteers.

Electrophysiological and behavioral evidence suggests that morphine may have a differential effect on nociceptive and thermal pathways. In this study, we explored the perceptual consequences of these differential actions by examining the effect of a low morphine dose (0.08 mg/kg) on pain and temperature sensations arising from cutaneous thermal stimuli. In a double-blind placebo-controled study, we compared the perceived temperature intensity and perceived pain intensity and unpleasantness of noxious and innocuous heat and cold applied to the face of human subjects, with and without low doses of systemic morphine. The results showed that morphine modified pain-related sensations. In contrast, perceived thermal intensity of both noxious and innocuous heat or cold stimuli was unchanged by low-dose morphine administration. These findings suggest that low doses of morphine have a differential effect on pain and temperature sensations arising from the same stimulus, and thus that these sensations could be subserved by different neuronal populations. Copyright 1999 European Federation of Chapters of the International Association for the Study of Pain.

Journal Article↗

PubMed1999

Stroke-like episodes in autosomal recessive cytochrome oxidase deficiency.

Stroke-like episodes, defined as periods of acute localized neurological dysfunction during which brain imagery suggests cerebral ischemia but vascular anatomy is normal, occurred in 3 patients with autosomal recessive Saguenay-Lac St-Jean (SLSJ) cytochrome oxidase (COX) deficiency. The patients developed focal neurological deterioration and frontal hypodensities on cerebral computerized tomography (CT). Arteriography, performed in 1 patient during an acute episode, showed normal vascular anatomy. Nevertheless, capillary shunting was evident both in regions that appeared abnormal on the initial cerebral CT study and in regions that appeared normal but subsequently developed Leigh disease. Stroke-like episodes did not exacerbate systemic acidosis, and acidotic decompensations occurred independently of stroke-like episodes. In conclusion, stroke-like episodes occur in autosomal recessively inherited congenital lactic acidoses as well as in those caused by mitochondrial DNA mutations. In some cases, acute localized neurovascular changes occur in regions that subsequently develop Leigh disease.

Brain↗

PubMed1999

Effects of resveratrol on the rat brain respiratory chain.

The aim of this work was to investigate the possible effects of resveratrol on the mitochondrial respiratory chain in rat brains. Isolation of mitochondria was performed at 4 degrees C using differential centrifugation. Mitochondrial respiration rate (0.4 mg of protein/ml) was determined by measuring mitochondrial oxygen consumption with a Clark electrode at 37 degrees C. Respiratory control ratio (RCR) was evaluated as the state 3/state 4 ratio of oxidative phosphorylation with substrates adenosine 5'-diphosphate (ADP) and malate plus glutamate, respectively in the presence and in the absence of resveratrol. The rate of oxygen consumption by the different complexes was checked using rotenone (2 microM), malonate (10 mM), antimycin A (1 microM), potassium cyanide (KCN) (0.3 mM) and oligomycin (10 microM) to inhibit complexes II, III, IV, V and I, respectively. Moreover, enzyme activity determinations were checked as follows: the activities of complexes II-III were measured as the rate of cytochrome c reduction at 550 nm (37 degrees C) successively triggered either by succinate (complexes II and III) or by decylubiquinol (DUQH2) (complex III), in the presence and in the absence of resveratrol. Adenosine 5'-triphosphate (ATP) synthase activity was checked as ATP hydrolysis (ATPase) at 37 degrees C for 10 min from purified mitochondria on Percoll gradient. The inorganic phosphate (Pi) concentration was measured by the Fiske and Subbarow method. When complexes I to V were activated by glutamate plus malate, resveratrol (10(-11) - 10(-4) M) significantly decreased RC (p < 0.001) following a biphasic curve with two EC50 values, 0.162 +/- 0.072 microM and 24.5 +/- 4.0 microM, representing about 56% of total oxygen consumption inhibition. We also observed a concentration-dependent effect on state 3 with two EC50 values, 2.28 +/- 0.87 nM and 27 +/- 5 microM respectively. On the other hand, resveratrol inhibited state 4 following a concentration-dependent curve with an EC50 of 37 +/- 11 microM. When complex IV operated alone, resveratrol (100 microM) did not modify oxygen consumption compared with control, indicating that this molecule did not inhibit complex IV. Thus resveratrol inhibits the mitochondrial respiratory chain through complexes I to III. In order to confirm these data, we measured the enzymatic activity of ubiquinol cytochrome c reductase alone and in the presence of resveratrol. In the presence of disrupted mitochondria, after freeze thawing cycles (three times), resveratrol inhibited about 20% of complex III activity. These results suggest that resveratrol and DUQH2 could be competitive on complex III. Resveratrol significantly inhibited ATPase activity (p < 0.001) following a biphasic curve with two EC50 values, 0.39 +/- 0.15 nM and 23.1 +/- 6.4 microM, both representing about 80% of oligomycin-dependent ATPase total activity. Resveratrol was effective as a protecting agent on the three models of oxidation. On lipid peroxidation of brain synaptosomes induced by the Fenton reaction, it was three times more potent than DUQH2. Its effectiveness in reducing 1,1-diphenyl-2-picryl hydrazyl radical (DPPH degrees) showed a stoichiometry of two, indicating that two hydrogen atoms of resveratrol were abstracted by the process. Resveratrol was also able to scavenge the superoxide anion (O2 degrees) generated from rat forebrain mitochondria in a concentration dependent manner. In conclusion, resveratrol can decrease complex III activity by competition with coenzyme Q. This property is especially interesting as this complex is the site where reactive oxygen substances (ROS) are generated. By decreasing the activity of complex III, resveratrol cannot only oppose the production of ROS but can also scavenge them.

Adenosine Triphosphatases↗

PubMed1999

[Treatment of idiopathic scoliosis in children during the growth period].

Idiopathic infantile and juvenile scoliosis have potential for extreme worsening. Orthopaedic treatment should be started as soon as the progressivity of the scoliosis is proven. In some infantile curves healing is possible, but in most cases the aim of the orthopaedic treatment will be to avoid spinal fusion at the end of growth. In some malignant infantile scoliosis, curves are rapidly out of the orthopaedic treatment control, and in such cases early surgery could be discussed.

Child↗

PubMed1999

Ultrasound assessment of the acetabulum in the infant hip.

One hundred and fifty infant hips were studied using simultaneous ultrasonography and radiography. The reliability of measurement was found to be similar for alpha angle and d/D ratio. However, the acetabular index correlated much better with the d/D ratio than with the alpha angle. In fact, in hips where the d/D ratio exceeded 56%, radiographs could be dispensed with. Besides, the use of a sector scanner or a linear-array tranducer was found to make no significant difference to the correlation between the acetabular index and the d/D ratio. Sonographic assessment of acetabular development in the infant should permit a reduction in the number of radiographs required during screening and follow-up.

Acetabulum↗

PubMed1999

[Industrial progress concerning latex allergy in surgery].

Latex allergy has been well described in the literature, but it remains a constant worry for high-risk groups. We wish to show that the manufacturing industry has made real progress in response to this iatrogenic pathology. The high-risk groups are defined, in addition to the allergies with which they are associated: foodstuffs, ethylene oxide, airborneallergens. The criteria necessary to have available high-quality sterile surgical gloves are stated: they must be either hypo-allergenic or non-allergenic dependent upon the circumstances of use, they must guarantee protection against the transmission of infection and allow the medical practitioner complete freedom of movement. In the same way urinary catheters for intermittent probing, penile sheaths and condoms are mentioned. Powder must definitely be eliminated from any medical glove, because it can both be a vector for latex particles and can be the cause of granulomas in the abdominal cavity. The European Community standards (CE) and the recommendations of the American Associations of Allergology are explained. Sterilization by gamma irradiation is one sign of real progress, outperforming ethylene oxide which is too allergenic. The composition of the gloves must ensure an effective barrier against both allergens and infections. Pre-lubricated latex-free urinary catheters, penile sheaths and latex-free condoms represent substantial improvements for the population at risk. Since 1995 considerable progress has been made by the manufacturing industry in response to the needs of both allergologists and surgeons.

Drug Industry↗

PubMed1998

Glucocorticoids decrease cytochrome c oxidase activity of isolated rat kidney mitochondria.

The importance of mitochondria is rising as a target in pathologic processes such as ischemia. We have investigated the effects of hydrocortisone, prednisolone, dexamethasone and triamcinolone on oxidative phosphorylation, Ca2+ fluxes, swelling and membrane potentials in isolated kidney mitochondria. The measurement of respiration state 3 showed a significant decrease in presence of glucocorticoids whereas the other respiration states were not modified. When mitochondria were uncoupled and either the complexes III and IV or the complex IV were stimulated, the O2 consumption was decreased by glucocorticoids. These results suggest the cytochrome c oxidase is a target of the glucocorticoid effect on the respiratory chain. Indeed, the other mitochondrial functions investigated were unchanged, ruling out a direct effect on Ca2+ fluxes or swelling. A regulation of cytochrome c oxidase activity by glucocorticoids will be of particular interest in pathology involving metabolic insult.

Animals↗