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M Gibbs

Publications and source records attributed to M Gibbs.

At least 37 records · Page 2Linked to original sources
PubMed1999

Confirmation of prostate cancer susceptibility genes using high-risk families.

Data from many types of studies support the hypothesis that strong familial components are involved in the etiology of prostate cancer. One way to access such genes is through the study of families with multiple affected family members and, in particular, families with individuals affected comparatively early in life. Several prostate cancer susceptibility loci have been described to date. Confirmation of the linkage and estimation of the proportion of families who are linked in large independent datasets is essential to understanding the significance of susceptibility genes. We explore the methodology used to perform such studies and the factors that can limit the ability to confirm linkage results. We report specifically the example of the HPC1 gene on 1q24-25.

Chromosome Mapping↗
PubMed1999

A comparison of the bioavailabilities of oral and intravenous ethanol in healthy male volunteers.

OBJECTIVES: Ethanol (EtOH), the antidote for methanol and ethylene glycol, is administered by the oral (PO) and intravenous (IV) routes. Serum concentrations (SCs) of 100 mg/dL or more are targeted for clinical effect. This study was completed to validate the assumption that there are minimal differences in SC achieved between these two routes. METHODS: Twenty healthy male volunteers were randomized to receive either PO or IV EtOH. Subjects abstained from EtOH for 48 hours before each phase. After a seven-day washout period, the subjects crossed over to the other group. Inclusion criteria were no history of medical problems, age between 21 and 40 years, and actual body weight within 10% of ideal weight. Baseline EtOH SCs were obtained before participation in each phase. Two hours after a standard breakfast, the subjects received 700 mg/kg of PO or IV EtOH. PO EtOH was administered as a 20% solution in juice over 10 minutes. IV EtOH, controlled by an infusion pump, was administered as a 10% solution over 30 minutes. Blood was drawn for EtOH SCs at 45, 75, 105, 135, 165, 225, 285, and 345 minutes after start of the dose. RESULTS: All initial EtOH SCs were 0. EtOH SCs were higher after IV administration. Mean peak SC was 103.6 mg/dL after IV administration and 71.3 mg/dL after PO administration (p<0.0001). Mean time to peak was 46.5 minutes after IV administration and 103.5 minutes after PO administration (p<0.0001). Total area under the curve was 17,440 min-mg/dL after IV administration and 13,875 min-mg/dL after PO administration (p<0.003). The order of treatments did not affect results (p>0.1). CONCLUSION: Significant differences exist between the SCs of EtOH as well as the times to peak SC after PO and IV administrations.

Administration, Oral↗
PubMed1999

Patient preference for oral sumatriptan 25 mg, 50 mg, or 100 mg in the acute treatment of migraine: a double-blind, randomized, crossover study. Sumatriptan Tablets S2CM11 Study Group.

BACKGROUND: Dosing recommendations for oral sumatriptan have ranged from 25 mg to 100 mg. Patient dose preferences are clinically relevant (perhaps moreso than traditional efficacy endpoints) and deserve study. METHODS: A multinational randomized double-blind crossover study was conducted over 18 weeks to assess patient dose preference, efficacy, and tolerability for oral sumatriptan (25 mg, 50 mg, and 100 mg) in the acute treatment of migraine; 257 patients treated three attacks, using a different dose for each. RESULTS: The 100 mg dose was preferred by 35% of patients, 31% the 50 mg dose, and 25% the 25 mg dose. Efficacy and speed of action were the two main reasons given for preferring the higher doses. Compared with the 25 mg dose, the 100 mg and 50 mg doses were significantly more likely to provide headache relief at 2, 3, and 4 h after dosing and complete headache resolution at 3 and 4 h after dosing (P < 0.027). Recurrence rates were similar for the three doses, ranging from 33% to 38%, though the median time to recurrence increased with dose, from 8.5 to 11.8 h. The 25 mg, 50 mg, and 100 mg doses were all well tolerated, with adverse event incidences of 19%, 21%, and 30%, respectively. CONCLUSIONS: Patients preferred the 50 mg and 100 mg doses of oral sumatriptan to the 25 mg dose, and the higher doses were more effective against migraine; however, the 25 mg and 50 mg doses were better tolerated than the 100 mg dose. Though the 50 mg dose probably has the best effectiveness-to-tolerability ratio, some patients clearly prefer a higher dose.

Acute Disease↗
PubMed1999

The fate of cryopreserved sperm acquired during vasectomy reversals.

PURPOSE: Intraoperative sperm banking has been recommended during vasectomy reversal. These specimens are maintained as insurance for possible future intracytoplasmic sperm injection. We evaluated the fate of specimens collected intraoperatively from 48 vasectomy reversal patients. MATERIALS AND METHODS: Of 75 men 48 (64.0%) agreed to intraoperative sperm banking during vasectomy reversal. A total of 135 vials of epididymal sperm, 81 vials of testicular tissue and 13 vials of vasal sperm were cryopreserved. RESULTS: Among couples who stored sperm 10 (20.8%) voluntarily discarded the specimens within 4 months of vasectomy reversal. Specimens from 31 couples (64.5%) remain in storage. Seven couples (14.6%) have used frozen sperm for intracytoplasmic sperm injection. In 3 of these couples the men were azoospermic after surgery, 2 men had 10,000 to 15,000 sperm per ml. in the ejaculate with limited motility and 2 had 1 to 2 million sperm per ml. with limited motility. The 7 women who underwent intracytoplasmic sperm injection ranged between 37 and 39 years old, which was older than the mean age of the remaining study group (32.7 years). With intracytoplasmic sperm injection fertilization was achieved in all cases and 20 of 47 eggs (42.5%) developed into embryos. Of 7 women 4 achieved biochemical pregnancies (57.1%) and 2 (28.6%) delivered newborns with epididymal sperm. Natural pregnancy occurred in 7 of 16 vasectomy reversal couples (43.7%) who were followed at least 18 months postoperatively but the time to pregnancy averaged 1 year. CONCLUSIONS: Cryopreservation of sperm collected at vasectomy reversal is recommended for patients undergoing vasoepididymostomy or vasovasostomy. The couples who used the cryopreserved sperm for intracytoplasmic sperm injection included husbands whose postoperative ejaculate remained azoospermic or severely oligospermic and wives who were approaching 40 years old. Only a limited number of couples (14.6% of the study group) have used the cryopreserved sperm but the delivered newborn rate (28.6%) was comparable to other intracytoplasmic sperm injection data. The natural pregnancy rate after vasectomy reversal was 43.7% but the time to pregnancy after surgery was lengthy (average 1 year). These findings may be helpful for counseling couples who are planning vasectomy reversal surgery and may be considering intraoperative sperm banking.

Adult↗
PubMed1998

Clinical, serologic, and immunogenetic features of familial idiopathic inflammatory myopathy.

OBJECTIVE: To describe the clinical, serologic, and immunogenetic features of familial idiopathic inflammatory myopathy (IIM) and to compare these with the features of sporadic IIM. METHODS: Clinical signs and symptoms, autoantibodies, HLA-DRB1 and DQA1 alleles, and GM/KM phenotypes were compared among 36 affected and 28 unaffected members of 16 unrelated families in which 2 or more blood relatives developed an IIM. In addition, findings in patients with familial IIM were compared with those in 181 patients with sporadic IIM. The families included 3 pairs of monozygotic twins with juvenile dermatomyositis, 11 families with other siblings or relatives with polymyositis or dermatomyositis, and 2 families with inclusion body myositis. RESULTS: The clinical features of familial IIM were similar to those of sporadic IIM, although the frequency of myositis-specific autoantibodies was lower in familial than in sporadic IIM. DRB1*0301 was a common genetic risk factor for familial and sporadic IIM, but contributed less to the genetic risk of familial IIM (etiologic fraction 0.35 versus 0.51 in sporadic IIM). Homozygosity at the HLA-DQA1 locus was found to be a genetic risk factor unique to familial IIM (57% versus 24% of controls; odds ratio 4.2, corrected P = 0.002). CONCLUSION: These findings emphasize that 1) familial muscle weakness is not always due to inherited metabolic defects or dystrophies, but may be the result of the development of IIM in several members of the same family, and 2) multiple genetic factors are likely important in the etiology and disease expression of familial IIM, as is also the case for sporadic myositis, but DQA1 homozygosity is a distinct risk factor for familial IIM.

Adolescent↗
PubMed1998

Truth, virtue and beauty: midwifery and philosophy.

In this paper, we outline three moments in the history of Western philosophy--Classical Greek, Modernity, Postmodernity--and the ways in which issues of truth, virtue and beauty have been understood within these philosophical formations. In particular, we investigate the ways in which notions of truth, virtue and beauty influenced the orthodoxy of birthing practices at these different moments. Finally, we examine current, critical reflections on the role of the intellectual in postmodern society and use these reflections as a heuristic for understanding the role of the contemporary midwife. We suggest that midwifery must reconcile two divergent demands. The first is to mobilise the positive, instrumental benefits of Western medical science to improve mortality and morbidity outcomes. The second is to remain sensitive to the cultural and social meanings attached to traditional birthing practices and to understand the roles these play in the well-being of mother and child.

Adult↗
PubMed1998

Cardiorespiratory responses and circulating metabolite concentrations in male and female adolescents during a simulated duathlon.

This study compared markers of the metabolic processes occurring in male and female adolescent triathletes from two age groups (over 15 years of age [O15] and under 15 years of age [U15]) during a laboratory based duathlon. Participants were tested on three separate occasions; two peak VO2 tests on a treadmill and cycle ergometer, and a third session involved a simulated duathlon (2 km run, 12 km ride and 4 km run for the O15 group or 1 km run, 8 km ride and 2 km run for the U15). Data collection included performance speed, cardiorespiratory responses and blood borne markers of exercise metabolism. The performance speeds selected by the two age groups did not differ. The mean relative percentage of VO2peak at which subjects participated were 79+/-3, 77+/-4%, for the O15 males and females, and 71+/-5 and 82+/-2%, for the U15 males and females, respectively. While the plasma metabolites of ammonia [NH3] and lactate [La] were not different between age groups and sex (p>0.05) there were however, higher concentrations recorded during the cycling phase when compared with the running phases (p < 0.05). The respective mean concentrations for NH3 and La were 80.5+/-5.6 microM, and 4.9+/-0.3 microM for cycling, and 56.3+/-2.7 microM, and 2.7+/-0.2 microM for the combined running phases.

Adolescent↗
PubMed1998

Testicular infarction in a patient with epididymitis.

To the authors' knowledge, this case is unique to the emergency medicine literature. Although testicular infarction from epididymitis is rare, it should be considered as a complication of severe or unresolving epididymitis. These patients should be placed on broad spectrum antibiotics, i.e., quinolones; color flow Doppler of the testes should be obtained; and urologic consultation should be considered for possible admission and surgical exploration.

Adult↗
PubMed1997

Construction of a panel of canine-rodent hybrid cell lines for use in partitioning of the canine genome.

We have constructed a collection of canine-rodent microcell hybrid cell lines by fusion of canine fibroblast microcell donors with immortalized rodent recipient cells. Characterization of the hybrid cell lines using a combination of fluorescence in situ hybridization and PCR analysis of canine microsatellite repeat sequences allowed selection of a panel of hybrids in which most canine chromosomes are represented. Approximately 90% of genetic markers and genes that were tested could be assigned to 1 of 31 anonymous canine chromosome groups, based on common patterns of retention in the hybrid set. Many of these putative chromosome groups have now been validated by linkage analysis. This panel of cell lines provides a tool for development of genetic, physical, and comparative maps of the canine genome.

Animals↗
PubMed1997

A linkage map of the canine genome.

A genetic linkage map of the canine genome has been developed by typing 150 microsatellite markers using 17 three-generation pedigrees, composed of 163 F2 individuals. One hundred and thirty-nine markers were linked to at least one other marker with a lod score > or = 3.0, identifying 30 linkage groups. The largest chromosome had 9 markers spanning 106.1 cM. The average distance between markers was 14.03 cM, and the map covers an estimated 2073 cM. Eleven markers were informative on the mapping panel, but were unlinked to any other marker. These likely represent single markers located on small, distinct canine chromosomes. This map will be the initial resource for mapping canine traits of interest and serve as a foundation for development of a comprehensive canine genetic map.

Animals↗
PubMed1997

Polymorphic repeats in the androgen receptor gene: molecular markers of prostate cancer risk.

We analyzed the polymorphic (CAG)n and (GGN)n regions within the androgen receptor gene from participants in a population-based case-control study of prostate cancer in middle-aged (40-64 years) Caucasian men. The associations between repeat lengths and risk of prostate cancer and the effects of confounding and modifying factors, such as age, family history of prostate cancer, and body mass index, were evaluated. DNA was available for 301 cases and 277 controls. The overall age-adjusted relative odds of prostate cancer associated with the number of (CAG) repeats as a continuous variable was 0.97 [95% confidence interval (CI), 0.92-1.03], suggesting a 3% decrease in risk of prostate cancer for each additional (CAG) repeat. Further analyses identified several subgroups at increased risk. These were men with less than the median number of CAG repeats (< 22) that were younger [< 60 years; relative odds (RO), 1.47; 95% CI, 0.96-2.25], had an affected first-degree relative (RO, 1.59; 95% CI, 0.62-4.14), or were relatively thin (Quetelet index < 24.4; RO, 2.21; 95% CI, 1.07-4.69). Although only the latter result was statistically significant, these results are provocative and support the hypothesis that (CAG)n array length is a predictor of risk for prostate cancer. Similar analyses of (GGN)n showed that with the exception of men with a family history of prostate cancer and those in the highest quartile of body mass index, men with < or = 16 repeats had higher risk estimates than did men with > 16 repeats. Overall, those men who had < or = 16 repeats had a significant elevation in risk (RO, 1.60; 95% CI, 1.07-2.41). When both repeat lengths were considered jointly, the subgroup with two short repeats (CAG, < 22; GGN, < or = 16) had a 2-fold elevation in odds (RO, 2.05; 95% CI, 1.09-3.84) relative to those with two long repeats (CAG, > or = 22; GGN, > 16). These data suggest that determination of both androgen receptor repeats within germ-line DNA may be useful in assessing an individual's risk of developing prostate cancer.

Adenocarcinoma↗
PubMed1997

Thoracic aortic dissection secondary to crack cocaine ingestion.

Thoracic aortic dissection is a rare but recognized complication of crack cocaine inhalation. It is thought to be triggered in some cases by transient severe elevations in blood pressure, causing a shear effect on the thoracic aorta. Unrecognized, it can result in high morbidity and mortality. A case of an unusual presentation of thoracic aortic dissection following crack cocaine ingestion is reported.

Adult↗
PubMed1997

Linkage analysis of 49 high-risk families does not support a common familial prostate cancer-susceptibility gene at 1q24-25.

Linkage of a putative prostate cancer-susceptibility locus (HPC1) to chromosome 1q24-25 has recently been reported. Confirmation of this linkage in independent data sets is essential because of the complex nature of this disease. Here we report the results of a linkage analysis using 10 polymorphic markers spanning approximately 37 cM in the region of the putative HPC1 locus in 49 high-risk prostate cancer families. Data were analyzed by use of two parametric models and a nonparametric method. For the parametric LOD-score method, the first model was identical to the original report by Smith and coworkers ("Hopkins"), and the second was based on a segregation analysis previously reported by Carter and coworkers ("Seattle"). In both cases, our results do not confirm the linkage reported for this region. Calculated LOD scores from the two-point analysis for each marker were highly negative at small recombination fractions. Multipoint LOD scores for this linkage group were also highly negative. Additionally, we were unable to demonstrate heterogeneity within the data set, using HOMOG. Although these data do not formally exclude linkage of a prostate cancer-susceptibility locus at HPC1, it is likely that other prostate cancer-susceptibility loci play a more critical role in the families that we studied.

Adult↗
PubMed1997

Chicken microsatellite markers isolated from libraries enriched for simple tandem repeats.

The total number of microsatellite loci is considered to be at least 10-fold lower in avian species than in mammalian species. Therefore, efficient large-scale cloning of chicken microsatellites, as required for the construction of a high-resolution linkage map, is facilitated by the construction of libraries using an enrichment strategy. In this study, a plasmid library enriched for tandem repeats was constructed from chicken genomic DNA by hybridization selection. Using this technique the proportion of recombinant clones that cross-hybridized to probes containing simple tandem repeats was raised to 16%, compared with < 0.1% in a non-enriched library. Primers were designed from 121 different sequences. Polymerase chain reaction (PCR) analysis of two chicken reference pedigrees enabled 72 loci to be localized within the collaborative chicken genetic map, and at least 30 of the remaining loci have been shown to be informative in these or other crosses.

Animals↗
PubMed1995

Phosphorylation changes following weakly reinforced learning and ACTH-induced memory consolidation for a weak learning experience.

The formation of a protein synthesis-dependent long-term memory stage in day-old chicks trained on a passive discriminated avoidance task has been shown to occur only with an adequate level of reinforcement, and is preceded by a significant change in the phosphorylation state of the forebrain synaptosomal membrane protein GAP43 protein. In the present study, it is shown that weakly reinforced training did not lead to formation of a long-term memory stage or to any change in phosphate incorporation into forebrain P2M protein bands. However, administration of ACTH immediately posttraining led to both the formation of the long-term memory stage and a preceding significant increase in the phosphorylation of GAP43. These findings are consistent with the view that a reinforcement-dependent neurohormone-mediated change to the phosphorylation of this synaptosomal membrane protein may be implicated in the triggering of long-term memory consolidation.

Animals↗