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Biomedical subjects

R Martin

Publications and source records attributed to R Martin.

At least 325 records · Page 18Linked to original sources
PubMed1996

Optimizing the time-frame for the definition of bleeding-related death after acute variceal bleeding in cirrhosis.

OBJECTIVE: To identify the best time-frame for defining bleeding-related death after variceal bleeding in patients with cirrhosis. DESIGN: Prospective long-term evaluation of a cohort of 155 patients admitted with variceal bleeding. SETTING: Eight medical departments in seven hospitals in north-eastern Italy. METHODS: Non-linear regression analysis of a hazard curve for death, and Cox's multiple regression analyses using different zero-time points. RESULTS: Cumulative hazard plots gave two slopes, the first corresponding to the risk of death from acute bleeding, the second a baseline risk of death. The first 30 days were outside the confidence limits of the regression curve for the baseline risk of death. Using Cox's regression analysis, the significant predictors of overall mortality risk were balanced between factors related to severity of bleeding and those related to severity of liver disease. If only deaths occurring after 30 days were considered, only predictors related to the severity of liver disease were found to be of importance. CONCLUSION: Thirty days after bleeding is considered to be a reasonable time-frame for the definition of bleeding-related death in patients with cirrhosis and variceal bleeding.

Adult↗
PubMed1996

In vitro activities of eight macrolide antibiotics and RP-59500 (quinupristin-dalfopristin) against viridans group streptococci isolated from blood of neutropenic cancer patients.

From January 1988 to December 1994, 66 consecutive blood culture isolates of viridans group streptococci collected from febrile neutropenic cancer patients were tested for antimicrobial susceptibilities by the agar dilution method. The antibiotics studied were erythromycin, clarithromycin, roxithromycin, dirithromycin, azithromycin, josamycin, diacetyl-midecamycin, spiramycin, and quinupristin-dalfopristin. A total of 26 (39.4%) strains were resistant to erythromycin with an MIC range of 0.5 to > 128 micrograms/ml. The strains were classified into three groups according to their penicillin susceptibility: 42 (63.6%) were susceptible, 8 (12.1%) were intermediately resistant, and 16 (24.3%) were highly resistant. The percentages of erythromycin-resistant strains in each group were 23.8, 62.5, and 68.8%, respectively. Streptococcus mitis was the species most frequently isolated (83.3%) and showed the highest rates of penicillin (40%) and erythromycin (43.6%) resistance. MICs of all macrolide antibiotics tested and of quinupristin-dalfopristin were higher for penicillin-resistant strains than for penicillin-susceptible strains. All macrolide antibiotics tested had cross-resistance to erythromycin, which was not observed with quinupristin-dalfopristin. Our study shows a high rate of macrolide resistance among viridans group streptococci isolated from blood samples of neutropenic cancer patients, especially those infected with penicillin-resistant strains. These findings make macrolides unsuitable prophylactic agents against viridans group streptococcal bacteremia in this patient population.

Anti-Bacterial Agents↗
PubMed1996

Total UK multi-centre experience with a novel arterial occlusion device (Duct Occlud pfm).

OBJECTIVE: To report the total UK multicentre experience of a novel arterial occlusion device (Duct Occlud pfm). DESIGN: Descriptive study of selected non-randomised paediatric patients with a variety of aortopulmonary connections. SETTING: Five UK tertiary referral centres for congenital heart disease. PATIENTS AND METHODS: Between March 1994 and February 1995, 57 children aged 2 weeks to 14 years (median 50 months) underwent attempted closure of their aortopulmonary connection. Fifty one had persistent arterial ducts and 9 of them had had a Rashkind umbrella device implanted. Five patients had superfluous modified Blalock-Taussig shunts (mBTS). In one there was also a native major aortopulmonary collateral artery (MAPCA). Another patient had a native major aortopulmonary connection (APC). Transcatheter occlusion was attempted in all cases through a 4 F delivery catheter. RESULTS: Devices were successfully deployed in 49/57 (86%) patients. Seven of 51 cases with persistent arterial ducts were judged too large for the device and a Rashkind umbrella was used. 40 (91%) of the 44 in whom the detachable coil device was used had complete occlusion at 24 hours on colour flow Doppler echocardiography. Devices were successfully deployed in all 6 remaining patients (4 mBTS, 1 mBTS + MAPCA, and 1 APC). Embolisation of a device occurred on 4 occasions. Two devices were not retrieved but caused no apparent clinical problems. CONCLUSION: This novel detachable coil type occlusion system compares favourably with other methods of transcatheter occlusion of native, residual, or surgically created aortopulmonary shunts. The delivery system allows its use in small children.

Adolescent↗
PubMed1996

Mapping of the gene for cleidocranial dysplasia in the historical Cape Town (Arnold) kindred and evidence for locus homogeneity.

Cleidocranial dysplasia (CCD) is an autosomal dominant disorder, features of which include a patient anterior fontanelle, a bulging calvarium, hypoplasia or aplasia of the clavicles, a wide public symphysis, dental anomalies, vertebral malformation, and short stature. The Cape Town kindred which is under our genetic management was originally described more than four decades ago and now consists of more than 1000 people. Following reports of rearrangements on chromosomes 6 and 8 in people with CCD, we have carried out linkage analyses between highly information microsatellite dinucleotide repeat markers in the rearranged regions and the disorder in a branch of this South African CCD kindred, consisting of 38 subjects, 18 of whom are affected. Maximum lod scores (at theta = 0.00) of 7.14 (for marker D6S459), 4.32 (TCTE), 4.99 (D6S452), 5.97 (D6S269), and 3.95 (D6S465) confirm linkage of the disorder to the short arm of chromosome 6. Our data indicate that the CCD gene is located within a minimal region of approximately 10 cM flanked by the marker D6S451 distally and D6S466 proximally. This information is vital towards isolating and characterising the gene for CCD, and is being used to construct a physical map of 6p21.1-6p21.3. More importantly, mapping of the locus in the South African kindred of mixed ancestry, in which the "founder" of the disorder was of Chinese origin, suggests that a single locus is responsible for classic CCD.

Child↗
PubMed1996

Quantitative aspects of interorgan relationships among arginine and citrulline metabolism.

The quantitative roles of the splanchnic region and the kidneys in whole body (WB) arginine and citrulline metabolism were assessed in postabsorptive mongrel dogs with primed constant intravenous infusions of [15N2-guanidino, 5,5-2H2]arginine and [13C-ureido]citrulline or [13C-guanidino]arginine and [15N]urea tracers. Isotope and metabolite concentration balances of arginine and citrulline were measured across the gut, liver, splanchnic region, and kidneys, together with WB arginine and citrulline fluxes and urea production rate. The WB citrulline flux and rate of citrulline to arginine (C-A) conversion were 16 and 9.4 mumol.kg-1.h-1, respectively. Concentration balance of citrulline across kidneys was +8.2 mumol.kg-1.h-1, and metabolism of citrulline by kidneys was 8.7 mumol.kg-1.h-1, which was derived about equally from intestine and liver. The appearance rate of citrulline-derived arginine in renal vein was 6.8 mumol.kg-1.h-1. These three separate estimates of C-A conversion within the kidneys were in good agreement, indicating 40% of blood C-A conversion occurring outside kidneys. These findings of interorgan metabolism are discussed in reference to the current knowledge derived largely from studies in laboratory rodents.

Animals↗
PubMed1996

The legislative and litigation history of special education.

Between the mid 1960s and 1975, state legislatures, the federal courts, and the U.S. Congress spelled out strong educational rights for children with disabilities. Forty-five state legislatures passed laws mandating, encouraging, and/or funding special education programs. Federal courts, interpreting the equal protection and due process guarantees of the Fourteenth Amendment to the U.S. Constitution, ruled that schools could not discriminate on the basis of disability and that parents had due process rights related to their children's schooling. Congress, in legislation now retitled the Individuals with Disabilities Education Act (IDEA), laid out detailed procedural protections regarding eligibility for special educational services, parental rights, individualized education programs (IEPs), the requirement that children be served in the least restrictive environment, and the need to provide related (noneducational) services. Decisions on instructional matters such as curricula and the elements of the IEP remain the province of local and state authorities. Advocates for students with disabilities have continually sought separate (categorical) funding for special education services. Current movements toward block grants rather than categorical programs and toward greater inclusion of special education students in general education classrooms raise concerns in some quarters about whether students with disabilities will continue to have full access to the special services they need. While the cost of special services may be an unexpressed criterion in many decisions made by school districts, nowhere does the IDEA explicitly allow cost to be considered. Where a service is necessary for an individual child, cost considerations would not allow a school district to escape its obligations to the child. However, in instances where more than one appropriate configuration of services is available to meet a child's needs, the school district may be allowed to consider the cost of different alternatives.

Adolescent↗
PubMed1996

[Side effects of influenza vaccination in patients over 60 years of age].

The purpose of this study was to investigate the various factors affecting the incidence of adverse reactions after influenza immunization with either a subunit or an inactivated whole-virus vaccine. A total of 1,959 nursing home residents in Geneva (mean age: 84 +/- 8 years, sex ratio: 3F/1M) were randomly allocated to the two vaccine groups. Results showed that the incidence of local adverse reactions could be reduced by using the subunit vaccine injected into the buttock or the internal aspect of the thigh, in preference to the deltoid muscle. Moreover, this study demonstrated that intramuscular injection lowers the risk of local reactions but tends to increase the incidence of general reactions. Implementation of these recommendations should reduce the frequency of side effects due to influenza vaccination and, consequently, raise the rate of acceptance and the immunization coverage of the populations exposed to risk.

Age Factors↗
PubMed1996

[Influence of genetic factors on multiple sclerosis].

Epidemiological studies have provided evidence for a genetic contribution to the susceptibility of multiple sclerosis (MS). One in six patients has at least one affected family member. The concordance rate is approximately 25% in monozygotic twins, and 3% in siblings, however the prevalence in adopted siblings is similar to the general population (0.1%) MS is thought to be a T cell-mediated autoimmune disease and therefore genes controlling the immune response have been studied intensively as potential susceptibility factors. The best documented association was found for genes of the human-leukocyte antigen complex. Other possible susceptibility genes may reside in the regions of the T cell receptors and the tumour necrosis factors. So far it is clear, that MS is a multifactorial disease in which several genes must be involved. Population genetics and molecular biology will help to characterise further these susceptibility factors.

Autoimmune Diseases↗
PubMed1996

Cross-modal correspondence between vision and olfaction: the color of smells.

Cross-modal sensory correspondences between vision and audition have been well described, but those between vision and olfaction have not. In Experiment 1, a method previously used to relate color names, mood names, and line elements was replicated and extended to describe odors by color. Significant color characterizations were found for all 20 test odors. Test-retest correlations showed color-odor correspondences to be as stable as nonodor measures after 2 years. In Experiment 2, new subjects matched Munsell color chips to the test odors. Thirteen odors had characteristic hues; there was significant variation in chroma and value. The selected Munsell hues corresponded to the color names endorsed in Experiment 1. Together, these experiments suggest the existence of robust correspondences between vision and olfaction.

Adolescent↗
PubMed1996

Physical and topographical mapping among Triticeae chromosomes.

Three principal approaches have been used in our laboratory to analyze Triticeae genomes. (i) Synteny analysis: synteny among different Gramineae genomes was studied employing the elegant system of the Agropyron chromosome-induced deletion lines of wheat. Deletion mapping, predominantly of the homoeologous group 7 chromosomes, has led to the construction of a high density physical consensus map of wheat. The integration of wheat, barley and oat RFLP markers proves the colinearity between the wheat A-, B- and D-genomes, the H-genome of barley, and the E-genome of Agropyron. (ii) Light microscopic in situ techniques: the recent improvement of a drop technique for plant protoplasts was crucial for the sensitivity enhancement of fluorescence in situ hybridization (FISH), the efficient preparation of plant chromosomes for high resolution scanning electron microscopy, mapping of low-copy sequences, and comparative in situ hybridization. A tandemly amplified repetitive sequence element from microdissected barley chromosomes has enabled the karyotyping of Gramineae genomes in a single step. We have isolated and characterized members of this element family from other Triticeae species using PCR. The significant interspecific sequence differences were useful to identify single plant genomes, chromosomes and chromosome segments via post-hybridization washes under different stringency conditions. These sequences are also useful for simultaneous double or triple hybridization experiments in an attempt to localize new sequences on specific chromosomes or chromosome segments. The physical mapping of the Sec-1 locus has been refined on the satellite of chromosome 1R of rye, and the syntenic locus on barley chromosome 1H was identified. (iii) Physical mapping of rDNA sequences by high resolution electron microscopy: a method was developed for in situ hybridization and signal detection using high resolution field emission scanning electron microscopy and a backscattered electron detector. Colloidal gold particles were localized on chromosome structures resembling the 30 nm fibre. An rDNA probe was located in the secondary constriction and the highly compact adjacent regions of barley chromosomes.

Chromosome Mapping↗
PubMed1995

Resistance to penicillin and cephalosporin and mortality from severe pneumococcal pneumonia in Barcelona, Spain.

BACKGROUND: Penicillin-resistant strains of Streptococcus pneumoniae are now found worldwide, and strains with resistance to cephalosporin are being reported. The appropriate antibiotic therapy for pneumococcal pneumonia due to resistant strains remains controversial. METHODS: To examine the effect of resistance to penicillin and cephalosporin on mortality, we conducted a 10-year, prospective study in Barcelona of 504 adults with culture-proved pneumococcal pneumonia. RESULTS: Among the 504 patients, 145 (29 percent) had penicillin-resistant strains of S. pneumoniae (minimal inhibitory concentration [MIC] of penicillin G, 0.12 to 4.0 micrograms per milliliter), and 31 patients (6 percent) had cephalosporin-resistant strains (MIC of ceftriaxone or cefotaxime, 1.0 to 4.0 micrograms per milliliter). Mortality was 38 percent in patients with penicillin-resistant strains, as compared with 24 percent in patients with penicillin-sensitive strains (P = 0.001). However, after the exclusion of patients with polymicrobial pneumonia and adjustment for other predictors of mortality, the odds ratio for mortality in patients with penicillin-resistant strains was 1.0 (95 percent confidence interval, 0.5 to 1.9; P = 0.84). Among patients treated with penicillin G or ampicillin, the mortality was 25 percent in the 24 with penicillin-resistant strains and 19 percent in the 126 with penicillin-sensitive strains (P = 0.51). Among patients treated with ceftriaxone or cefotaxime, the mortality was 22 percent in the 59 with penicillin-resistant strains and 25 percent in the 127 with penicillin-sensitive strains (P = 0.64) The frequency of resistance to cephalosporin increased from 2 percent in 1984-1988 to 9 percent in 1989-1993 (P = 0.002). Mortality was 26 percent in patients with cephalosporin-resistant S. pneumoniae and 28 percent in patients with susceptible organisms (P = 0.89). Among patients treated with ceftriaxone or cefotaxime, mortality was 22 percent in the 18 with cephalosporin-resistant strains and 24 percent in the 168 with cephalosporin-sensitive organisms (P = 0.64). CONCLUSIONS: Current levels of resistance to penicillin and cephalosporin by S. pneumoniae are not associated with increased mortality in patients with pneumococcal pneumonia. Hence, these antibiotics remain the therapy of choice for this disease.

Adult↗