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Biomedical subjects

M Roy

Publications and source records attributed to M Roy.

At least 163 records · Page 9Linked to original sources
PubMed1994

Apolipoprotein E polymorphism and heterozygous familial hypercholesterolemia. Sex-specific effects.

The impact of apolipoprotein (apo) E polymorphism on interindividual variation in plasma lipid, lipoprotein, and apolipoprotein levels was studied in a sample of familial hypercholesterolemic (FH) patients (147 women, 116 men) with the same mutation, a > 10-kilobase deletion of the low-density lipoprotein (LDL) receptor gene. Each trait was adjusted for concomitants (age, age squared, height, weight, weight squared) for each sex separately before the apoE genotypic effects were estimated. The relative contribution of concomitants to sample variability was found to be very different in women and in men. Allelic variation in the apoE gene was shown to explain a statistically significant portion of the variability in adjusted lipid traits. Moreover, the contribution of apoE polymorphism was different between sexes. In women, there was significant variability (P < .01) among apoE genotypes for total cholesterol, LDL cholesterol, and total and LDL apoB. In men, significant variability (P < .01) was observed among apoE genotypes in very-low-density lipoprotein (VLDL) cholesterol and triglyceride levels. Women with the epsilon 3/2 genotype had significantly lower means for total cholesterol, LDL cholesterol, and LDL apoB than women with the epsilon 3/3 genotype (P < .05). In men, the mean VLDL cholesterol was significantly higher for the epsilon 2/2 genotype and was significantly lower for the epsilon 4/2 genotype than the mean for the epsilon 3/3 genotype (P < .05). Overall, the greatest influence was associated with the epsilon 2 allele, and the LDL cholesterol-lowering effect of this allele was present only in FH women. No statistically significant apoE effect was shown on lipoprotein(a) levels in either sex.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Granulometry and measurement of a aerosol drug deposit (fusafungine) in normal and pathological airways].

We measured with a laser velocimeter granulometric deposit of an aerosol anti-infectious agent, fusafungin, administered with a controlled inhalator. Total drug deposit was determined on the basis of a granulometric spectrum of the polydispered aerosol (mass mean aerodynamic diameter (MMAD) = 2.8 +/- 1.7 microns) and dispersion in the airways was estimated using the Stahlhofen model. We first compared deposits obtained with oral inhalation in 19 normal subjects and 20 patients with chronic obstructive lung disease. Total deposit in the airways of patients with chronic obstructive lung disease (82%) was not significantly different from that in normal subjects (85%). Estimated dispersion in normal airways was 27% in the alveoles, 8.4% in the tracheobronchic region and 23.5% in the extrathoracic regions. We then compared deposits after nasal inhalation in 22 normal subjects and 21 patients with rhinitis: nasal deposit was significantly greater in patients with rhinitis (54.5%) than in controls (44.7%). We conclude that such an inhalator can be adapted for local treatment of ENT infections and upper respiratory infections. Deposit is not modified in case of obstructive bronchopathy.

Adult↗
PubMed1994

Fallacies of the fine needle aspiration cytology of surgical lesions of liver.

Seventy-six cases of surgical hepatomegaly were subjected to fine needle aspiration cytology (FNAC) for initial diagnosis. Primary malignancies, as suspected clinically with adjunction of other investigative procedures, were 29 cases of whom 25 were confirmed by biopsy or therapy. Secondary deposits in liver were 27 of whom 15 were confirmed by therapy. Inflammatory lesions were 9 of whom 6 were confirmed by therapeutic response with specific therapy. Benign lesions were 10 of whom 5 were confirmed by surgery. Diagnosis of malignancies of liver is rather easier than that of benign lesions like hydatid cysts of liver which were Casoni's test negative; and hepatocellular adenoma, as the aspirate in the former is clear fluid and that of the latter is only normal looking liver cells. Thus, in respect of benign lesions of liver, FNAC diagnosis may be clinched after due consideration to the clinical findings, radiological and ultrasonographic findings and ultimately confirmed by exploration. Thus the fallacy lies in aspiration of normal looking liver cells whereby the histology may prove it to be hepatocellular adenoma, well differentiated hepatocellular carcinoma and secondary deposits where the exact site has not been hit. Ultrasonogram (USG) guidance helps in these cases where the same facility is available. This fallacy can again be avoided, where USG guidance is not available, by imparting due importance to clinical findings, USG findings and also by repeat smear.

Biopsy, Needle↗
PubMed1994

Absence of HTLV-I infection in some Indian populations.

A total of 946 adults belonging to ten population groups of Uttar Pradesh and West Bengal were screened for HTLV-I using a gelatin particle agglutination test. The percentage of seroreactive cases varied from 0 to 5.8 per cent. The overall prevalence of seroreactivity was 2 per cent. Of the 19 seroreactive cases, 15 were subjected to Western blot analysis, none could be confirmed. HTLV-I infection is, therefore, absent in these populations.

Adolescent↗
PubMed1994

Cytomegalovirus-related sequence in an atypical cytopathic virus repeatedly isolated from a patient with chronic fatigue syndrome.

An atypical virus, cytopathic for human and animal fibroblasts, was repeatedly cultured from a patient with chronic fatigue syndrome. Viral particles, suggestive of cytomegalovirus (CMV) were seen by electron microscopy. Infected cells did not, however, stain with antisera specific for CMV, herpes, simplex virus, or human herpes-virus-6. Polymerase chain reaction (PCR) assays for these viruses were also negative. Two distinct products of approximately 1.5 kilobase pairs were amplified from virally infected cells using the human T lymphotropic virus-II tax gene reactive primer, SK44, in low stringency PCR. Sequencing of one of the amplified products showed a region of highly significant partial homology with the UL34 gene of CMV. The sequence of the other PCR product did not correspond with CMV or any other virus. DNA was extracted from the material pelleted by ultracentrifugation of filtered culture supernatants. It migrated in agarose gels as a single band of approximately 20 kpb. The banded DNA was digested with EcoRI and cloned. A 2.2 kbp plasmid containing the CMV-related sequence identified within the PCR product was recovered. Sequencing of this plasmid extended the region of partial sequence homology with CMV to include a portion of the UL35 gene of CMV. Initial sequencing of additional plasmids has confirmed the partial relatedness to CMV. The data indicate a novel type of CMV-related "stealth" virus that is able to establish a clinically persistent human infection.

Adult↗
PubMed1993

In vivo CD40-gp39 interactions are essential for thymus-dependent humoral immunity. I. In vivo expression of CD40 ligand, cytokines, and antibody production delineates sites of cognate T-B cell interactions.

T-B cell interactions have a central role in the development of antibody responses. Upon activation, T helper (Th) cells express the ligand for CD40, gp39, which is essential for Th cell-dependent B cell activation. The cytokines produced by activated Th cells have a regulatory role in B cell differentiation. In this study, we investigated, using immunohistochemical techniques, the in vivo time course and localization of gp39 expression and cytokine production in relation to the specific antibody production. Both the immunization with keyhole limpet hemocyanin (KLH), a thymus-dependent (TD) antigen, and trinitrophenyl (TNP)-Ficoll, a thymus-independent type 2 (TI-2) antigen, induced Th cells to express gp39. The expression of gp39 was restricted to Th cells in the outer periarteriolar lymphocyte sheaths (outer-PALS) and around the terminal arterioles (TA). Incidentally, gp39+ Th cells were found in the corona of follicles, whereas gp39+ cells were never found in the germinal centers or marginal zones of the spleen. Maximum frequencies of gp39+ cells were observed 3 and 4 d after primary and secondary immunization with KLH. After injection of TNP-Ficoll, a marked increase in gp39+ cells was observed, confirming previous observations that activated T cells are involved in TI-2 antibody responses. Analysis of the in vivo cytokine production revealed that interleukin 2 (IL-2)-, IL-4- and interferon gamma (IFN-gamma)-producing cells (IFN-gamma-PC) developed according to similar kinetics as observed for gp39+ cells. IL-2-PC and IL-4-PC were present in higher frequencies as were IFN-gamma-PC in the immune response against TNP-KLH. Double staining experiments revealed gp39+ Th cells producing IL-2, IL-4, or IFN-gamma, suggesting that these cells were involved in both the initial activation as well as the differentiation process of B cells into antibody-forming cells. Dual immunohistochemical analysis revealed gp39+ T cells and cytokine-PC in close proximity to antigen-specific, antibody-forming B cells. In conclusion, this study shows that in vivo gp39 is expressed on activated Th cells after immunization with TD and TI-2 antigens. Furthermore, the time course and compartmentalization of gp39+ expression, cytokine production and antibody formation after immunization suggest that cognate T-B cell interactions and T cell-regulated B cell differentiation occur in the outer-PALS and around the TA of the spleen.

Animals↗
PubMed1993

Familial hypercholesterolemia in French-Canadians: taking advantage of the presence of a "founder effect".

The frequency of familial hypercholesterolemia (FH) in the Province of Quebec is twice that observed in most population samples. In the French-Canadian population, 5 mutations in the low density lipoprotein (LDL) receptor gene account for 76% of FH cases diagnosed using clinical and biochemical criteria. One of these mutations, a > 10 kilobase (kb) deletion at the 5' end of the gene involving the promoter and exon 1, is present in 60% of FH patients studied in Montréal. This high frequency is attributable to a "founder effect." Contribution to this founder effect included strategies in 17th century France for the settlement of a small number of pioneers, local incentives for early marriages and large families, and geographic and cultural isolation; these factors also favored endogamy. The > 10 kb deletion is present on only one haplotype in all patients studied so far (homozygotes and heterozygotes), a major advantage for studies relating phenotypic variation to haplotype variation in the normal LDL receptor allele of these hemizygous patients. Indeed, the presence of founder effects facilitates screening, genetic counseling, and treatment. It also confers a number of advantages for research: (1) the search for new causes of FH in the 24% unaccounted for to date; (2) the study of the geographic distribution of mutations and population movements; (3) the identification of gene-gene interactions in the etiology of disease; (4) the evaluation of factors modulating phenotypic expression and search for LDL-lowering genes; and (5) the study of genetic determinants of therapeutic response.

Consanguinity↗
PubMed1993

The regulation of the expression of gp39, the CD40 ligand, on normal and cloned CD4+ T cells.

Studies have established that gp39, the ligand for CD40, induces B cell cycle entry and is involved in the initiation of the humoral immune response. Expression of gp39 has been observed on normal, activated CD4+ T cells, activated lymph node cells; an activated Th1 clone, and an activated Th2 clone. Anti-CD3-activated CD8+ T cells did not express gp39; however, CD8+ T cells activated with PMA/ionomycin expressed gp39. The kinetics of anti-CD3-induced gp39 expression on a T cell clone and on splenic CD4+ T cells showed that gp39 was detectable at 4 h after activation, reaching maximal levels between 6 to 8 h postactivation and returning to near resting levels between 24 to 48 h. Lymphokines modulated the expression of gp39 on activated T cells. Expression of gp39 was inhibited by IFN-gamma on activated Th1, Th2, and CD4+ T cells; whereas TGF-beta inhibited gp39 expression only on the Th2 clone studied. All other lymphokines tested were without substantial effect. Differences in the expression of gp39 on activated naive and memory T cells were observed, as well as differences in requirements for optimal gp39 expression on these subsets. There are correlations between gp39 expression and effector function; however, anti-CD3-activated splenic CD4+ cells that express gp39 did not exhibit effector function. A comparison of the relative numbers of molecules of gp39 shows that activated Th1 clones express at least 20-fold the number of gp39 molecules/cell compared with activated splenic CD4+ cells. This may imply that density of gp39 on the activated T cells plays an important role in determining effector function.

Animals↗
PubMed1993

Mutations of low-density-lipoprotein-receptor gene, variation in plasma cholesterol, and expression of coronary heart disease in homozygous familial hypercholesterolaemia.

Variation in plasma-cholesterol concentration and the expression of coronary heart disease in patients with homozygous familial hypercholesterolaemia (FH) is well documented, but the underlying reasons for variation are not clearly defined. Because FH is caused by mutations at the low-density-lipoprotein-gene locus, we compared plasma-cholesterol concentrations in 21 FH homozygotes with either the greater than 10 kb deletion (promoter region and exon 1) (11 subjects) or the exon 3 missense (trp66-->gly) mutation (10 subjects) of the low-density-lipoprotein gene. Subjects with the greater than 10 kb deletion had a higher mean plasma-cholesterol concentration than those with the exon 3 mutations (26.7 vs 16.1 mmol/L; p = 0.000006), and there was no overlap in individual plasma-cholesterol concentrations between subjects in the two groups. Although the frequency of coronary heart disease was similar in the two groups, age-of-onset was earlier in subjects with the greater than 10 kb deletion (p = 0.059). Also, coronary deaths were more frequent (p = 0.044) and occurred at an earlier age (p = 0.009) in subjects with the greater than 10 kb deletion. Our results provide evidence that there is less variation in plasma-cholesterol concentrations among FH homozygotes when they are subdivided into groups according to low-density-lipoprotein-receptor-gene defect. Furthermore, differences in plasma-cholesterol concentrations are reflected in the severity of coronary heart disease expression.

Adolescent↗
PubMed1993

Genetic epidemiology of autosomal recessive spastic ataxia of Charlevoix-Saguenay in northeastern Quebec.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a disorder that has an elevated frequency in Saguenay-Lac-St-Jean (SLSJ) and Charlevoix, two geographically isolated regions in the past of northeastern Quebec. The incidence at birth and the carrier rate in SLSJ were estimated at 1/1,932 liveborn infants and 1/22 inhabitants, respectively, for the period 1941-1985. The mean inbreeding coefficient was twice higher and the mean kinship coefficient 3 times higher among the ARSACS families than among control families. In the SLSJ region, the birth places of the ARSACS individuals and their parents did not show a clustered distribution. The genealogical reconstruction suggests that the high incidence of ARSACS in SLSJ and Charlevoix is likely to be the result of a founder effect. Because the disease is apparently unknown elsewhere in the world and a high proportion of French Canadians presently living in eastern Quebec have ancestors coming from Perche, a small region in France, it also suggests that a unique mutation accounts for most, if not all, of the ARSACS cases known in these regions.

Consanguinity↗
PubMed1993

Study of enzyme polymorphism and haemoglobin patterns amongst sixteen tribal populations of central India (Orissa, Madhya Pradesh, and Maharashtra).

A survey was conducted to study the genetic differentiation among 16 tribal groups of Orissa, Madhya Pradesh, and Maharashtra belonging to different ethnic and linguistic affiliations. Sixteen hundred and fifteen blood samples from both sexes were tested for 5 red cell enzyme systems: ACP, ESD, PGD, GLO, LDH, and Hb pattern. Three hundred and nineteen male individuals were tested for G-6-PD enzyme deficiency. The distribution of the enzyme markers and Hb show a range of variation which are more or less within the Indian range. Cases of homozygous HbSS were detected in all the tribes except 3 tribes in Orissa. Two cases of LDH Cal-1 homozygote were found in two Dravidian language speaking Orissa tribes. The chi 2-values for testing the homogeneity of gene frequencies indicate a non-significant heterogeneity for all alleles in the individual system. Within population diversity seems to be larger than between population diversity. The degree of over all genetic differentiation as measured by GST value is 0.0154 +/- 0.0071.

Alleles↗
PubMed1993

Amrinone, in combination with norepinephrine, is an effective first-line drug for difficult separation from cardiopulmonary bypass.

A crucial element for weaning patients from cardiopulmonary bypass (CPB) rests on the selection of an appropriate therapeutic regimen. Amrinone, a phosphodiesterase III inhibitor, combines inotropic support with pulmonary and systemic vasodilatation, without increasing heart rate (HR) or myocardial oxygen consumption. These characteristics should be useful in the failing heart during weaning from CPB. Nineteen patients were included in this prospective, open-labelled, phase IV study when systolic blood pressure (DPAP) > 15 mmHg or central venous pressure (CVP) > 15 mmHg, during progressive separation from CPB. At that moment, CPB flow was increased to alleviate heart failure and amrinone administered as a bolus (0.75 mg.kg-1) followed by an infusion (10 micrograms.kg-1.min-1). Weaning from CPB was then resumed and haemodynamic variables (SBP, DPAP, CVP and HR) were compared with those measured at CPB flow when failure had first occurred. Failure to wean from CPB occurred at 57 +/- 28% of full pump flow. After the amrinone bolus, DPAP and CVP decreased by 20% and 21% respectively. Subsequently, 16 patients required the infusion of norepinephrine (4-8 micrograms.min-1) to maintain a SBP > 80 mmHg. Heart rate remained unchanged after the bolus of amrinone, after separation from CPB, and no arrhythmias were noted. Successful weaning from CPB was possible 12 +/- 8 min after the amrinone bolus. Weaning resulted in a cardiac index similar to that measured pre-bypass. Amrinone is rapidly effective during weaning from CPB and, in combination with norepinephrine, provides the necessary inotropic support during this unstable period.

Aged↗
PubMed1993

Response of MTX-resistant V79 cells to some DNA-damaging agents.

Three methotrexate (MTX)-resistant clones selected at 200 nM MTX have been isolated from UV-irradiated V79 cells and were marked M1, M2 and M3. Two further clones were also isolated by gradually exposing M1 to higher concentrations of MTX and marked M4 and M5, isolated at 1200 nM and 2400 nM MTX respectively. The frequency of the induction of MTX-resistant clones by UV light was found to increase significantly on treatment of the irradiated cells with either 3-aminobenzamide or caffeine. The resistant clones had the same sensitivity as the parental cells to UV light, but were resistant to gamma-rays, MNNG and H2O2. In MTX-resistant cells low-dose H2O2-induced repair function was absent. UV-induced mutation at the HGPRT locus was the same in MTX-resistant as sensitive cells, whereas for MNNG-induced mutation it was higher in resistant cells. The rate of SCE induction by UV light was higher in MTX-resistant cells compared to the parental ones, but was not significantly different for induction by MNNG and H2O2.

Animals↗
PubMed1993

Characterisation of methotrexate-resistant clones.

Three methotrexate (MTX)-resistant clones M1, M2 and M3 have been isolated from Chinese hamster V79 cells and characterised for aneuploidy, chromosomal aberrations, sister-chromatid exchange (SCE) mutation and transfection. Amplification of the dihydrofolate reductase (DHFR) gene in these clones has been established from (a) direct measurement of DHFR activity, (b) existence of double minute chromosomes and (c) homogeneously staining region (HSR) in chromosome number 2 by G-banding technique. Clone M1 on further exposure to gradually increasing concentrations of MTX gave rise to two more clones M4 and M5, resistant to 1200 nM and 2400 nM MTX, respectively. The levels of folate reductase activity in clones M4 and M5 were 21.90 units per 10(7) cells and 33.30 units per 10(7) cells, whereas the value was 13.90 units per 10(7) cells in clone M1 and 1.1 units per 10(7) cells in normal V79 cells. Increased chromosomal aberrations were observed in each of these clones in comparison to those in normal V79 cells. There was a correlation between the increase in DHFR activity and the increase in the level of background SCE as well as the increase in aneuploidy. However, background mutation frequency at the HGPRT locus remained unaffected though transfection frequency decreased.

Animals↗
PubMed1993

Idazoxan decreases estrogen-induced lordosis in female but not "hormone-independent" lordosis in male guinea pigs of an inbred strain.

This experiment examined whether the imidazoline idazoxan (which binds to alpha-noradrenergic receptors and to imidazoline-preferring sites) interferes with hormone-dependent or hormone-independent lordosis responses. Ovariectomized (ovx) Strain 2 female guinea pigs which were sexually receptive after receiving estradiol benzoate (EB; 3 micrograms/d for 3 days) were injected with either idazoxan (10 mg/kg) or with vehicle at 24 hr after the last EB injection. Idazoxan significantly decreased EB-facilitated lordosis responses in these females. Castrated Strain 2 males, which show lordosis behavior without gonadal hormone administration, were injected with the same dosage of idazoxan (10 mg/kg) or with vehicle. Idazoxan did not inhibit lordosis behavior in these males.

Adrenergic alpha-Antagonists↗