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Biomedical subjects

J L Rocha

Publications and source records attributed to J L Rocha.

At least 19 recordsLinked to original sources
PubMed2004

Acute hemiplegia associated with cat-scratch disease.

Cat scratch disease (CSD) is an infectious illness caused by a Gram-negative rod named Bartonella henselae. Typical CSD is characterized by a small skin lesion at the site of a scratch or a bite, followed by regional lymphadenopathy, one to two weeks later. Atypical forms may present as ocular manifestations, neurological manifestations, hepatosplenic involvement and vertebral osteomyelitis. Among neurological complications, encephalopathy is by far the most common. Other neurological manifestations are very rare. We report a case of an 11-year-old boy, with a posterior cervical lymphadenopathy and fever. Cat scratch disease was diagnosed and treated after a positive "Whartin-Starry" stain on lymph node biopsy. Two weeks after treatment, the patient was readmitted presenting an acute episode of left hemiplegia. A brain MRI demonstrated a right subcortical fronto-parietal lesion with no contrast enhancement. Complete recovery was observed after corticosteroid treatment.

Acute Disease↗
PubMed2004

Y-chromosome haplotypes in azoospermic Israeli men.

Among azoospermic and severely oligozoospermic men, 7-15% present microdeletions of a region on the long arm of the Y chromosome that has been called AZF (azoospermia factor). Because these deletions present varying relative frequencies in different populations, we decided to ascertain whether their presence was correlated with specific Y-chromosome haplotypes. For that, we evaluated 51 infertile Israeli men, 9 of whom had microdeletions in AZF. Haplotypes were identified using a hierarchical system with eight biallelic DNA markers. We also checked for the presence of the deletion marker 50f2/C, which was absent in all seven patients with isolated AZFc deletion and also in the one patient with isolated AZFb deletion, suggesting that these microdeletions overlap. As expected, haplogroup J was the most common (47%), followed by equal frequencies of haplogroups Y* (xDE, J, K), P* (xR1a, R1b8), K* (xP), and E. In six patients with AZFc deficiencies of comparable size, three belonged to haplogroup J, two belonged to haplogroup P* (xR1a, R1b8), and one belonged to haplogroup R1a. Also, there were no significant differences in the haplotype frequencies between the groups with and without microdeletions. Thus we did not identify any association of a specific haplogroup with predisposition to de novo deletion of the AZF region in the Israeli population.

Chromosomes, Human, Y↗
PubMed2001

Predictors of marker-informativeness for an outbred F2 design.

Generalization of the polymorphism information content (PIC) index to represent marker informativeness (MI) for a three-generation F2 design requires that two additional sources of non-informativeness be added to the PIC formula: the probability of matings between like-heterozygous F1 individuals, of which one is non-informative; and that of matings between like-heterozygous F1 individuals, which are both fully informative but where line of origin of the same alleles is reciprocal. Given the dense marker-maps currently available for some species, this F2 informativeness parameter constitutes the natural criterion for marker selection in F2 designs, and two computer programs to predict MI from grandparental marker-genotypes were developed for an F2 population originating from two divergent selection lines of outbred mice (F approximately 0.2). A total of 403 markers had been genotyped for the F0 grandparents (n=31), and 14 markers had also been genotyped in the complete pedigree including 559 F2 individuals. One program was based on assumptions of random-mating (RM), while the other (PED) accounted for the pedigreed mating structure. For the 403 markers, the correlation between MI from RM and from PED was 0.95, and the average deviation between the two predictions was 0.005 MI units (MI ranged from 0 to 1). Correlations between predicted and realized MI for the 14 fully genotyped markers were 0.97 for PED and 0.94 for RM, while the corresponding average of deviations between predicted and actual values were 0.01 and 0.04, respectively. Absolute deviations from realized MI never exceeded 0.09 and 0.16 for PED and RM, respectively. Simulated optimization of the mating system to maximize average MI of 28 markers on one chromosome led to improvements in the range of 15-20% average MI (0.07-0.09 MI units). The degree of relative advantage conferred by the F2 generalization of the PIC index over the traditional index was found to be of minor significance.

Animals↗
PubMed2001

Disaster mitigation and preparedness on the Nicaraguan post-Mitch agenda.

Nicaragua provides an example of how a major disaster, in this case Hurricane Mitch, can transform the national agenda for disaster mitigation and preparedness. Hurricane Mitch was a reminder of how extremely disaster prone Nicaragua is, and also how neoliberal reforms have weakened governmental response capacity. In the face of critiques of how governmental policies had affected preparedness and response, discussions of this transformation became a highly politicised process where the debate over alternative development models tended to overshadow the original calls to strengthen risk management. Progress can be seen in some areas, such as disaster mitigation through environmental management. This study of NGO roles, and their relations with other key actors, draws attention to the need to anchor improved risk management in local-level NGO-government collaboration. Structures are being put into place to achieve this aim, but dependence on donor financing raises questions regarding the longer-term sustainability of these efforts.

Community Participation↗
PubMed2000

Central venous sinus thrombosis following mastoiditis: report of 4 cases and literature review.

The frequency of mastoiditis and its complications have declined since the advent of antibiotics. Among all complications, transverse sinus thrombosis is the least frequent, although it may have the highest mortality rate. Before the introduction of surgery and antibiotic treatment, mortality was close to 100%. Previous administration of antibiotics may lead to changes in the clinical presentation of venous sinus thrombosis that make diagnosis more difficult, in spite of greatly improved imaging methods. This article reports 4 confirmed cases of venous sinus thrombosis complicating mastoiditis that were diagnosed and treated at Nossa Senhora das Graças Hospital, Curitiba--PR from June, 1999, to February, 2000. All 4 cases were documented by magnetic resonance imaging. Each patient recovered after treatment with antibiotics and anticoagulation. No surgical intervention was necessary. Diagnosis of the complication requires a high level of clinical suspicion and then evaluation by mastoid CT and cranial MRI.

Adult↗
PubMed1999

Molecular analyses of the vasopressin type 2 receptor and aquaporin-2 genes in Brazilian kindreds with nephrogenic diabetes insipidus.

Nephrogenic diabetes insipidus (NDI) is associated with germline mutations in two genes: vasopressin receptor type 2 (V2(R)) in X-linked NDI, and the water channel aquaporin-2, in autosomal-recessive disease. Genetic heterogeneity is further emphasized by reports of phenotypically abnormal individuals with normal structural genes. We analyzed both genes in five Brazilian families and the aquaporin-2 gene in two Swedish families with clinical and laboratory diagnosis of NDI, by a combination of denaturing gradient gel electrophoresis (DGGE) and direct DNA sequencing. A novel polymorphism in the aquaporin-2 gene (S167S), but no disease-associated mutations in any tested individual from all seven families, was detected. In two Brazilian families, frameshift mutations were detected in the V2(R) gene: one leading to a premature stop after codon 36 and the other to a longer peptide (462 aa instead of the 373 aa wild-type protein). In two other Brazilian families, probable disease-associated missense mutations were detected: an alanine to proline at codon 163 (A163P) and an asparagine to aspartic acid at codon 85 (D85N). In one Brazilian family, both genes were structurally normal and the aquaporin-2 gene was also normal in the two Swedish kindreds. This report further extends the mutational spectrum of NDI and suggests that there are other mutational or epigenetic events inactivating the two known genes or even novel genes that underlie NDI.

Adolescent↗
PubMed1999

Inverse paradoxical embolism in a patient on chronic hemodialysis with aortic bacterial endocarditis.

We present a 45-year-old patient on chronic hemodialysis who suffered aortic endocarditis by Staphylococcus haemolyticus after bacteremia associated with a venous catheter, which was used temporarily during the maturing phase of a Cimino-Brescia arteriovenous fistula in the left forearm. Three weeks after starting antibiotic therapy, the patient suffered a septic pulmonary embolism. The catheter had been removed 4 weeks before the embolism. Thrombophlebitis of lower limbs, infection or thrombosis of the vascular access, and the involvement of right-sided cardiac structures were all discarded. We assumed that the pulmonary episode was probably a consequence of the paradoxical passage of embolic material, detached from the aortic valve, from arterial to venous circulation through the arteriovenous fistula.

Aortic Valve↗
PubMed1999

Impaired kidney transplant survival in patients with antibodies to hepatitis C virus.

BACKGROUND: With a few exceptions, most published studies do not show an influence of antibodies to the hepatitis C virus (HCV) on the success of a kidney transplant. METHODS: We studied all our renal transplant recipients who had received kidneys from cadaver donors (n = 335) and had been treated with quadruple immunosuppression (steroids, azathioprine, and antilymphocyte antibodies, followed by cyclosporin). We had information on the status of the hepatitis C antibodies before and/or after the transplant in 320 cases (95.5%; in 300, pre-transplant). Patients with HCV antibodies before and/or after the transplant were considered to be HCV positive (HCV+). RESULTS: The HCV+ patients had more time in dialysis and a greater number of transfusions, hyperimmunized cases, and re-transplants. The evolution in the first post-transplant year was similar in both groups, but afterwards, the HCV+ patients had proteinuria more often as well as worse kidney function. The survival rate of the graft was significantly less in the HCV+ cases: 90.6, 68.3 and 51.0% at respectively 1, 5 and 10 years, compared with 91.5, 84.7 and 66.5% in HCV-patients (P<0.01). The patient survival rate was: 96.4, 87.0, and 71.9% in the HCV+ patients at 1, 5, and 10 years, compared with 98.2, 96.0 and 90.0% in the HCV- cases respectively (P<0.01). The differences remained the same in stratified studies according to time spent in dialysis or pre/post-transplant evolution of HCV antibodies, even when immunologically high-risk patients were excluded. In multivariant analysis, the presence of HCV antibodies acted as a independent prognostic factor for the survival of the kidney and the patient: 3.0 (1.8-5.0) and 3.1 (1.2-7.8) odds-ratio (95% of the confidence interval), respectively. The main cause of death among HCV+ patients was cardiovascular; there was no apparent increase in mortality rate due to infections or chronic liver disease. The loss of organs was mainly due to chronic nephropathy or death with a functioning kidney. CONCLUSION: The presence of hepatitis C antibodies, before or after transplantation, is associated with a worse long-term survival rate for both the patient and the transplanted kidney in our patients treated with quadruple therapy.

Adult↗
PubMed1998

Continuous intravenous intradialysis versus intravenous postdialysis erythropoietin therapy in chronic haemodialysis patients: a randomized, controlled, crossover study.

BACKGROUND: Subcutaneous recombinant human erythropoietin seems to be more effective than intravenous administration. Local pain, however, may diminish patient compliance with the subcutaneous route. Recently continuous intravenous intradialysis administration of rHuEpo has been reported to be more efficacious in stimulating erythropoiesis than the usual postdialysis intravenous bolus. METHODS: We conducted a randomized, controlled, crossover study on stable chronic haemodialysis patients to compare the efficacy of continuous intradialysis rHuEpo therapy with intravenous postdialysis administration. Twenty patients were selected and randomly assigned to receive rHuEpo either postdialysis (control phase) or by continuous intradialysis perfusion (slow Epo phase) for 12 weeks. After this period, patients were switched to the alternative method for 12 additional weeks. The erythropoietin dose remained unchanged during the study. Haematocrit was monitored weekly and iron metabolism, serum Epo, and vitamins were measured monthly. Urea kinetics and iPTH measurements were performed every 3 months. RESULTS: Three patients were excluded because of unrelated problems. The final mean haematocrit was unchanged from previous basal values in both phases and no statistical differences were found for any parameter between the groups. No differences were found in iron metabolism nor in urea kinetic parameters. CONCLUSIONS: Continuous intravenous intradialysis administration of rHuEpo is not more effective than an intravenous postdialysis bolus as rHuEpo maintenance therapy in stable chronic haemodialysis patients.

Adolescent↗
PubMed1998

Blood groups and milk and type traits in dairy cattle: after forty years of research.

This study addresses the utility of 11 blood groups as selection aids in Holstein breeding schemes and considers issues inherent to the approach of resolving quantitative variation into components that are due to quantitative trait loci. The data consisted of predicted transmitting abilities of 22,614 bulls, first lactation information on 1,924,171 cows, and type scores on 447,800 cows. Linear models were fitted under male half-sib designs, female half-sib designs, and granddaughter designs as well as under the assumption of direct effects of the markers. The evolution of allele frequencies through time was determined, and previous research results were synthesized according to criteria of consistency of biological significance. The inconsistency of results across studies and analytical designs alludes to the importance of the intrinsic nonadditivity of genetic and biological phenomena to quantitative trait locus detection and marker-assisted selection. In our analyses, three associations met the criteria of consistency--a C blood group effect on rump angle, an L effect on milk yield and composition traits, and an S effect on milk fat yield. The M locus appears to be directly associated with effects on milk and protein yields. An enhanced understanding of the biochemical and physiological bases of quantitative genetics should be a long-term objective of this type of genetic analysis.

Animals↗
PubMed1998

Trait-based analysis in dairy cattle using blood group polymorphisms.

The potential of trait-based analysis to detect quantitative trait loci was investigated using blood group polymorphisms as the marker systems and milk and type traits in Holstein cattle as the quantitative traits. Within large half-sib families, animals were ranked on their predicted transmitted abilities or phenotypes, and blood group allele frequencies were compared between the upper and lower 5% tails of the distributions. Genotype frequencies within large families were also examined for evidence of selection. All of the major effects that had previously been detected using linear model analyses were identified by the trait-based analyses of a C blood group effect on rump angle, an L effect on milk yield and composition traits, an S effect on milk fat yield, and a direct effect of the M locus on milk and protein yields. These results provide additional support for the biological validity of these associations and also demonstrate the utility of trait-based analysis for the detection of quantitative trait loci within existing dairy breeding programs. However, just as in the linear model analyses, an analytical strategy should be utilized that allows the identification of the effects that are consistent across environments and genetic backgrounds.

Alleles↗
PubMed1997

A novel polymorphism in the coding region of the vasopressin type 2 receptor gene.

Nephrogenic diabetes insipidus (NDI) is a rare disease characterized by renal inability to respond properly to arginine vasopressin due to mutations in the vasopressin type 2 receptor (V2(R)) gene in affected kindreds. In most kindreds thus far reported, the mode of inheritance follows an X chromosome-linked recessive pattern although autosomal-dominant and autosomal-recessive modes of inheritance have also been described. Studies demonstrating mutations in the V2(R) gene in affected kindreds that modify the receptor structure, resulting in a dys- or nonfunctional receptor have been described, but phenotypically indistinguishable NDI patients with a structurally normal V2(R) gene have also been reported. In the present study, we analyzed exon 3 of the V2(R) gene in 20 unrelated individuals by direct sequencing. A C-->T alteration in the third position of codon 331 (AGC-->AGT), which did not alter the encoded amino acid, was found in nine individuals, including two unrelated patients with NDI. Taken together, these observations emphasize the molecular heterogeneity of a phenotypically homogeneous syndrome.

Diabetes Insipidus, Nephrogenic↗
PubMed1996

Sporadic cardiac myxomas and tumors from patients with Carney complex are not associated with activating mutations of the Gs alpha gene.

Cardiac myxomas are rare tumors that may be encountered sporadically or in the context of the Carney complex. The molecular basis for the development of cardiac myxomas and Carney complex tumors is unclear. Pathological myocardial function and myocardial hypertrophy have been associated with alterations in the heterotrimeric GTP-binding proteins. The postulated proto-oncogenic character of the gene encoding the alpha sub-unit of the stimulatory GTP-binding protein Gs alpha (gsp) in pituitary and thyroid tumors, the finding of identical somatic gsp mutations in the myocardium of patients with McCune-Albright syndrome, and the associated endocrine anomalies of the Carney complex prompted us to investigate the occurrence of activating missense mutations in the Gs alpha gene in 10 sporadically occurring atrial myxomas and in 8 tumors from 7 patients with Carney complex. No gsp mutations could be demonstrated by using the polymerase chain reaction and denaturing gradient gel electrophoresis complemented by direct DNA sequencing. Thus, activating Gs alpha mutations neither are associated with the development of atrial myxomas, nor can be demonstrated in other tumors from patients with Carney complex. The significance of these mutations in the myocardium of asymptomatic patients with McCune-Albright syndrome remains to be determined.

Adult↗
PubMed1992

Interaction of parasitism and nutrition in goats: effects on haematological parameters, correlations, and other statistical associations.

Weaned wether goats (n = 144) approximately 6 months of age were placed in a 2 x 3 factorial experiment to test the effects and interaction of two levels of nutrition (growth+maintenance, NUT1; and twice growth+maintenance, NUT2) and three levels of Haemonchus contortus burden (0, 500, and 2000 larvae administered every 2 weeks; W0, W500, and W2000, respectively) on packed cell volume, red blood cell count, total serum protein and leukocytes. The statistical analysis revealed clear and proportionate differences among levels of infection for all variables. A significant (P < 0.05) nutritional effect was also found associated with all the variables except leukocytes. Nutrition by worm load interactions were found for packed cell volume and leukocytes. The neutrophil/lymphocyte ratio was higher in the NUT1-infected animals, leading to the nutrition by worm load interaction for leukocytes. An analysis for the different leukocyte types revealed significant (P < 0.05) differences among infection levels for lymphocytes, while nutrition level was found to be a significant effect for basophil count and immature white cells. Several significant correlations were observed between pairs of variables. Faecal egg output could be predicted from actual worm count in three of the four necropsy periods. The clear differences observed for blood parameters were not present in production traits, suggesting that physiological thresholds may play an important role in framing the metabolic activity of biological organisms. Total serum protein was the best indicator of these effects on production parameters.

Animal Feed↗