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Biomedical subjects

G Bouchard

Publications and source records attributed to G Bouchard.

At least 37 records · Page 2Linked to original sources

Multilocus markers for mouse genome analysis: PCR amplification based on single primers of arbitrary nucleotide sequence.

Polymerase chain reaction (PCR) based on single primers of arbitrary nucleotide sequence provides a powerful marker system for genome analysis because each primer amplifies multiple products, and cloning, sequencing, and hybridization are not required. We have evaluated this typing system for the mouse by identifying optimal PCR conditions; characterizing effects of GC content, primer length, and multiplexed primers; demonstrating considerable variation among a panel of inbred strains; and establishing linkage for several products. Mg2+, primer, template, and annealing conditions were identified that optimized the number and resolution of amplified products. Primers with 40% GC content failed to amplify products readily, primers with 50% GC content resulted in reasonable amplification, and primers with 60% GC content gave the largest number of well-resolved products. Longer primers did not necessarily amplify more products than shorter primers of the same proportional GC content. Multiplexed primers yielded more products than either primer alone and usually revealed novel variants. A strain survey showed that most strains could be readily distinguished with a modest number of primers. Finally, linkage for seven products was established on five chromosomes. These characteristics establish single primer PCR as a powerful method for mouse genome analysis.

Animals

Absorption of an alternate source of immunoglobulin in pups.

Newborn pups from 4 large litters were alloted to 6 groups to determine effect of time and route of administration on absorption of an alternate source of immunoglobulin. Selective absorption of specific classes of immunoglobulins was also investigated. The alternate source of immunoglobulin consisted of pooled serum that was administered either PO or SC. Control groups were either left with the dam (group C1) or fed milk replacer (group C2). Blood samples were collected from pups at birth and 24 hours. Immunoglobulin (IgA, IgG, IgM) concentrations were determined by use of radial immunodiffusion on samples of pooled serum, colostrum, and pups' serum (birth and 24 hours). Serum IgA concentration was less than the sensitivity of the procedure and was not included in the statistical analysis. Pups fed 8 ml of pooled serum at birth and 12 hours later (group T1) absorbed more (P less than 0.05) IgG and IgM than did group-C2 pups, but less (P less than 0.05) than did group-C1 pups. Pups fed 8 ml of pooled serum at 12 hours only had significant (P less than 0.05) increase of IgG concentration, but no absorption of IgM (P greater than 0.05) at 24 hours, compared with control pups (group C2). Pups administered 8 ml of pooled serum SC at birth (group SC1) had similar (P greater than 0.05) absorption of IgG and higher (P less than 0.05) absorption of IgM than did pups of group T1.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption

Polypoid cystitis, pyelonephritis, and obstructive uropathy in a cow.

Polypoid cystitis, pyelonephritis, and obstructive uropathy was found in a cow with hematuria, dysuria, and colic. The cow was treated with penicillin, multiple B vitamin supplementation, and isotonic sodium chloride. Polypoid cystitis, diagnosed in this cow by use of endoscopic examination, is a common response to chronic inflammation of the bladder and can lead to obstructive uropathy. Although endoscopic confirmation of this diagnosis may not always be feasible, recognition of corresponding clinical signs can allow timely, appropriate treatment.

Animals

Fertility in couples heterozygous for the tyrosinemia gene in Saguenay Lac-St-Jean.

A case-control study of 84 couples from Saguenay-Lac-St-Jean, jointly heterozygous for the tyrosinemia gene, was done to determine whether the birth of an homozygous child affected their fertility rates. The mean number of children born to tyrosinemia and control couples between 1940 and 1986 was not different (p greater than 0.05). The knowledge that tyrosinemia was an autosomal recessive disorder, with risk of recurrence in these families, did not appear to modify reproductive behaviour. Fertility fell significantly in both the tyrosinemia and control families in the period of observation. This change reflects the decline in fertility of French Canadians in general during this period.

Amino Acid Metabolism, Inborn Errors

Origin and diffusion of the myotonic dystrophy gene in the Saguenay region (Quebec).

A very high prevalence (approximately 1/475 in 1985) of myotonic dystrophy (Steinert disease) is observed in the Saguenay region, which is located in the north-east part of the Province of Quebec. For various reasons, however, the literature on the subject generally associates a high degree of selective disadvantage with this gene, which seems to contradict the Saguenay data. Using a computerized regional population register, we have reconstituted patients' genealogies and family biographies. We have thus been able to study the origin of the gene and to compare the demographic behavior of patients and controls. On the whole, patients seem to be very little disadvantaged compared to controls, in terms of reproduction as well as of geographical and occupational mobility.

Female

Genetic structure of the Saguenay, 1852-1911: evidence from migration and isonymy matrices.

The Saguenay is a region in northeastern Québec populated in the second half of the 19th century through migration from other parts of Québec. The present-day population of nearly 300,000 is the result of both immigration and high rates of intrinsic growth. This population has been of interest to geneticists because of the high incidence of certain hereditary diseases, notably spastic ataxia, tyrosinemia, agenesis of the corpus callosum, vitamin D-dependent rickets, and myotonic dystrophy. Parent-offspring migration and isonymy matrices were used to estimate random kinship using the Malécot model for six 10-year time periods from 1852-1911. Comparisons between two estimates of kinship--one from parent-offspring migration matrices (phi) and the other from isonymy (R)--and geographic distance were made using both product-moment and Mantel correlation. Comparisons of within- and between-subdivision kinship were made using nonparametric and Mantel correlation. Within-subdivision kinship from the phi matrix was also compared with kinship estimated from marriage dispensations for endogamous marriages. The estimates of random kinship from the parent-offspring matrices showed a good fit with geography. However, isonymy did not correlate well with geographic distance; and phi and R showed no correlation until the last two time periods, and the diagonal of phi did not correlate with the marriage dispensations. Examination of scatterplots of phi vs. R suggests that nonrandom migration during the process of settlement formation is responsible for the lack of correlation. While movement across space seems to be highly dependent on distance, nonrandom selection of migrants means that between-subdivision estimates of kinship based on migration are not congruent with those obtained by other methods. On the whole, genetic differentiation seems to have been low due to the high levels of movement between subdivisions and immigration. The weak dependence of genetic structure on geographic distances in the present population is demonstrated by mapping the geographic distribution of cases of three recessively inherited diseases.

Emigration and Immigration

[Spreading of the gene for myotonic dystrophy in Saguenay (Quebec)].

The prevalence of the myotonic dystrophy (Steinert disease) is about 1/475 in the Saguenay region, located in the North-east of the province of Québec (Canada). About 600 cases are currently known in a population of 285,000 inhabitants. This disease is an autosomal dominant disorder which causes a general muscular degeneration. Usually, it is also associated with a lower fertility, if not sterility, among the affected families. Another element of the phenotype is a higher infant mortality rate among cases. In the light of those traits, the very high prevalence of the disease in the Saguenay population becomes rather puzzling. It is the subject of this research. Using a computerized population register, we have been able to analyze the genealogies of the patients and their family history. In the overall, two basic factors account for the wide transmission of the gene: a) an immigration stream from a neighbouring region (Charlevoix) may have brought between 57 and 77 patients into the Saguenay since 1840; b) the cases proved to be by and large as fertile as controls (an average of 9.2 births among 85 affected families). The paper also presents a genealogical inference program used to ascertain cases among ancestors, along with data on the history of the gene, nuptiality, geographical and occupational mobility. In the overall, we have not been able to bring out an important selective disadvantage against the patients.

Female

Basic targets and the different epilepsies.

The follow up of 49 stereotactically operated epileptics is graphically demonstrated and the 79 operations in basic targets within the amygdala and the area of the anterior pole of the thalamus are described. The patients had valuable gaining in 80%; The continued developement of stereotactic methods in the future is urgent, so long as 30% of the epileptics respond poorly to drug therapy and only 5-10% are suitable to the traditional resection methods.

Adolescent

Thalamic evoked potentials to somatosensory stimulation in man.

Thalamic somatosensory evoked potentials (ThSEPs) were recorded by averaging technique from various thalamic structures during 59 stereotactic operations. From 372 records, response patterns and latency characteristics were analysed in relation to the intrathalamic localization. The findings can be summarized as follows. In N. ventro-caudalis (VC) and ventro caudalis parvocellularis (Vcpc) ThSEPs showed the most definite (and exclusively contralateral) responses characterized by a single positive (P1) deflection. The latency was shortest in VC (mean value, 17.5 msec) and in Vcpc (15.6 msec). Responses from N. centrum medianum (CM), parafascicularis (Pf) and limitans (Lim) were composed of early P1-N1 and of later P2-N2 components. The P1 latency was relatively consistent, with a mean value of 28.2 msec. Pulvinar responses showed a pattern similar to CM, with a mean P1 latency at 30.5 msec. Responses of N. dorsalis medialis (DM) were small, variable and longest, with a mean P1 latency of 54.2 msec. To ipsilateral stimulation, CM, Pul, DM and N. ventro-lateralis (VL) showed comparable wave forms. The possible role of the CM-Pf-Lim complex and of Pulvinar in the "extra-lemniscal" sensory system was considered. The usefulness of ThSEP recording to identify electrode locations in the thalamus is thus confirmed.

Adult

Evaluation of stereotactic thalamotomies for pain relief with reference to pulvinar intervention.

Stereotactic thalamotomies were carried out in 51 cases of malignant and 9 cases of other painful conditions. The patients were divided into two groups--those with a relatively small lesion created in the basal part of the CM nucleus and those with a larger lesion extending into the pulvinar. In total, 50% of the cases showed complete pain relief, 20% partial relief and 30% no effect. The group with pulvinar intervention showed better results, especially those with malignancies.

Follow-Up Studies