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Biomedical subjects

M Lima

Publications and source records attributed to M Lima.

At least 19 recordsLinked to original sources
PubMed2001

Demography and population dynamics of the mouse opossum (Thylamys elegans) in semi-arid Chile: seasonality, feedback structure and climate.

Here we present, to the authors' knowledge for the very first time for a small marsupial, a thorough analysis of the demography and population dynamics of the mouse opossum (Thylamys elegans) in western South America. We test the relative importance of feedback structure and climatic factors (rainfall and the Southern Oscillation Index) in explaining the temporal variation in the demography of the mouse opossum. The demographic information was incorporated into a stage-structured population dynamics model and the model's predictions were compared with observed patterns. The mouse opossum's capture rates showed seasonal (within-year) and between-year variability, with individuals having higher capture rates during late summer and autumn and lower capture rates during winter and spring. There was also a strong between-year effect on capture probabilities. The reproductive (the fraction of reproductively active individuals) and recruitment rates showed a clear seasonal and a between-year pattern of variation with the peak of reproductive activity occuring during winter and early spring. In addition, the fraction of reproductive individuals was positively related to annual rainfall, while population density and annual rainfall positively influenced the recruitment rate. The survival rates were negatively related to annual rainfall. The average finite population growth rate during the study period was estimated to be 1.011 +/- 0.0019 from capture-recapture estimates. While the annual growth rate estimated from the seasonal linear matrix models was 1.026, the subadult and adult survival and maturation rates represent between 54% (winter) and 81% (summer) of the impact on the annual growth rate.

Animals↗
PubMed2001

Association of CD4+/CD56+/CD57+/CD8+(dim) large granular lymphocytic leukemia, splenic B-cell lymphoma with circulating villous lymphocytes, and idiopathic erythrocytosis.

In this paper we report a rare association of a splenic marginal zone B-cell lymphoma with villous lymphocytes and a T-cell large granular lymphocytic leukemia coexpressing CD4 and CD8 as well as CD56 and CD57 natural killer-associated markers in an asymptomatic patient investigated because of an occasional finding of erythrocytosis and leukocytosis in routine blood analysis. We also discuss the possible reasons for this particular association.

Aged↗
PubMed2001

Influence of surgical reduction of intraocular pressure on regions of the visual field with different levels of sensitivity.

PURPOSE: To determine whether the ability to document improvement in visual fields after intraocular pressure (IOP) reduction can be enhanced by focusing on regions of the field with different levels of sensitivity. DESIGN: Cohort study. METHODS: This is a retrospective study. SETTING: Yale Eye Center. STUDY POPULATION: The visual fields (Octopus G2) of 30 eyes of 30 patients undergoing trabeculectomy. OBSERVATION PROCEDURE: Visual fields were evaluated a mean of three months before and 7.8 months after surgery. MAIN OUTCOME MEASURES: Change in sensitivity between the preoperative and postoperative visual fields (Delta S) was evaluated globally by comparing all 59 points of sensitivity and regionally in three groups according to preoperative sensitivity (pre-S): 25% of highest, 50% intermediate, and 25% of lowest points of sensitivity. Improvement in Delta S was also correlated with preoperative mean defect (pre-MD), percent intraocular pressure (IOP) reduction (Delta IOP%), and patient's age. RESULTS: Six visual fields showed improvement in Delta S when evaluated globally and nine showed improvement in pre-S subgroups. Of the latter, all nine showed improvement in the subgroup with the lowest pre-S, and two in the intermediate subgroup, but none in the subgroup with the highest pre-S. Combining the subgroups with the lowest pre-S and the highest Delta IOP% was associated with the highest mean Delta S. CONCLUSION: The ability to document improvement in visual fields following surgical reduction of IOP may be enhanced by focusing on subgroups of test points with lower baseline sensitivity.

Adult↗
PubMed2001

Immunophenotypic analysis of the TCR-Vbeta repertoire in 98 persistent expansions of CD3(+)/TCR-alphabeta(+) large granular lymphocytes: utility in assessing clonality and insights into the pathogenesis of the disease.

At present, a major challenge in the initial diagnosis of leukemia of large granular lymphocytes (LGLs) is to establish the clonal nature of the expanded population. In the present study we have analyzed by flow cytometry immunophenotyping the TCR-Vbeta repertoire of 98 consecutive cases of persistent expansions of CD4(+) or CD8(+bright) CD3(+)/TCR-alphabeta(+) LGLs and compared the results with those obtained in molecular studies of TCR-beta gene rearrangements. Fifty-eight cases were considered to be monoclonal in molecular studies whereas in the remaining 40 cases there was no evidence for monoclonality (11 cases were considered oligoclonal and 29 polyclonal). The TCR-Vbeta repertoire was biased to the preferential use of one or more TCR-Vbeta families in 96% of cases, a total of 124 TCR-Vbeta expansions being diagnosed: one TCR-Vbeta expansion in 71 cases and two or more TCR-Vbeta expansions in 23 cases. The highest TCR-Vbeta expansion observed in each case was higher among monoclonal (74 +/- 19%) as compared to nonmonoclonal cases (24 +/- 14%) (P = 0.001), as did the fraction of LGLs that exhibited a TCR-Vbeta-restricted pattern (86 +/- 16% and 42 +/- 23%, respectively; P = 0.0001); by contrast, the proportion of cases displaying more than one TCR-Vbeta expansion was higher in the latter group: 7% versus 48%, respectively (P = 0.001). Results obtained in oligoclonal cases were intermediate between those obtained in polyclonal and monoclonal cases and similar results were observed for CD4(+) as for CD8(+bright) T-cell expansions. TCR-Vbeta families expressed in CD8(+bright) T-cell-LGL proliferations showed a pattern of distribution that mimics the frequency at which the individual TCR-Vbeta families are represented in normal peripheral blood T cells. Assuming that a given proliferation of LGLs is monoclonal whenever there is an expansion of a given TCR-Vbeta family of at least 40% of the total CD4(+) or CD8(+bright) T-cell compartment, we were able to predict clonality with a sensitivity of 93% and a specificity of 80%. By increasing the cut-off value to 60%, sensitivity and specificity were of 81% and 100%. In summary, our results suggest that flow cytometry immunophenotypic analysis of the TCR-Vbeta repertoire is a powerful screening tool for the assessment of T-cell clonality in persistent expansions of TCR-alphabeta(+) LGLs.

Adolescent↗
PubMed2001

Natural selection at the MJD locus: phenotypic diversity, survival and fertility among Machado-Joseph Disease patients from the Azores.

Machado-Joseph Disease (MJD) is an autosomal dominant neurodegenerative disorder of adult onset, associated with the expansion of a (CAG)n tract in the coding region of the causative gene, localized on 14q32.1. Machado-Joseph Disease shows non-Mendelian features typical of other triplet repeat disorders, including clinical heterogeneity, variable age at onset and anticipation. Three phenotypes have been proposed (clinical types 1, 2 and 3). Type 1 is associated with early age at onset and a high repeat number of the CAG sequence, and Types 2 and 3 have later onset and lower numbers of CAG repeats. This paper investigates whether there is selection against the MJD gene, acting through differential survival. nuptiality and fertility associated with clinical type and age at onset. The study sample comprised 40 MJD patients from the Azores (Portugal) having fully documented reproductive histories and known dates of death. The proportion of married patients of each clinical type increased from 0.22 among Type 1 patients, to 0.40 in Type 2 and 0.95 in Type 3. Age at onset and length of survival were also associated with marital status, with the married cases having later mean age at onset and longer mean survival time. In the whole sample, clinical type was associated with fertility, with significantly fewer children born to Type 1 patients. Among married patients clinical type was not associated with age at marriage, reproductive span or number of children. No reduction of fertility was detected among married patients in whom the onset of MJD was below the age of 50. The authors' interpretation of these results is that the high-repeat CAG haplotypes associated with early age at onset and clinical Type 1 are selected against through reduced survival and fertility. The fertility component of selection is mediated by nuptiality rather than marital fertility.

Adolescent↗
PubMed2001

Antenatal diagnosis and early laparoscopic treatment of a rare variation of androgen-insensitivity syndrome.

Androgen-insensitivity syndrome (AIS) (Testicular feminisation or Morris syndrome) is characterised by external female genitalia and bilateral testes with a normal male karyotype. This kind of syndrome is transmitted recessively. Presence of hypoplastic and short "pseudo-vagina" is one of the characteristics of this syndrome. We report here a case of AIS in which there was a well-formed vagina (6 cm). The case was diagnosed antenatally and managed laparoscopically.

Adult↗
PubMed2001

Laparoscopic surgery of diaphragmatic diseases in children: our experience with five cases.

AIMS: In paediatric surgery the laparoscopic approach can be used to repair diaphragmatic anomalies originating from the abdomen or containing abdominal viscera. Candidates for laparoscopic correction are children with mild symptoms and good respiratory and haemodynamic conditions. The authors present their experience with 5 patients treated successfully for different types of diaphragmatic lesions. PATIENTS AND METHODS: Five children were treated laparoscopically since 1998. Two true Morgagni-Larrey hernias, one recurrent left Bochdalek hernia, one diaphragmatic dysontogenetic cyst and one huge congenital sliding and rolling hiatal hernia. All the herniated viscera were repositioned in the abdomen and the defects--including the diaphragmatic hole at the level of the dysontogenetic cyst--were directly sutured without the use of a mesh. RESULTS: All patients are healthy without signs of recurrence observed at chest X-ray after a follow-up of 3 months to 1 year. DISCUSSION: Under specific conditions the laparoscopic approach can be an effective and more advantageous alternative to laparotomy for diaphragmatic congenital diseases in a paediatric population.

Child↗
PubMed2001

Disease knowledge and attitudes toward predictive testing and prenatal diagnosis in families with Machado-Joseph disease from the Azores Islands (Portugal).

OBJECTIVE: Machado-Joseph disease (MJD) reaches its highest prevalence world-wide in the Azores, thus constituting a public health problem in these islands. The aim of the study was thus to (1) determine the level of knowledge about the disease; (2) estimate the expected level of request for predictive testing, and (3) analyse the intentions of at-risk individuals concerning their reproductive decisions. METHODS: A questionnaire on these points was distributed to 42 affected and 36 at-risk individuals. RESULTS: As expected, the educational level of the respondents was significantly associated with the level of knowledge about the disease. The survey indicated that 83.3% of the at-risk individuals would make use of predictive test and that 77.8% would make use of prenatal diagnosis. Of the latter, 36.1% would terminate pregnancy if confronted with a positive result for the fetus. CONCLUSIONS: The level of knowledge about MJD in the Azorean families is considered to be fair. Although the actual behavior can prove to be different from the intentions put forward by at-risk individuals based solely on the results of this study we can estimate that the request for a predictive test would be quite high. The intentions expressed by at-risk individuals seem to indicate that the prenatal diagnosis will have an effect on their reproductive decisions. Results obtained certify the importance of implementing genetic testing for MJD in the Azores.

Attitude to Health↗
PubMed2000

Ancestral origins of the Machado-Joseph disease mutation: a worldwide haplotype study.

Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disorder originally described in families of Portuguese-Azorean ancestry. The cloning of the MJD1 gene allowed identification of the disease in many other populations, and MJD is now known to be the most common cause of dominant spinocerebellar ataxia. The hypothesis that its present world distribution could result from the spread of an original founder mutation has been raised, both at historical and molecular levels. In the present study, we tested this hypothesis by linkage-disequilibrium analysis of tightly linked polymorphisms and by haplotype comparison, in 249 families from different countries. We typed five microsatellite markers surrounding the MJD1 locus (D14S1015, D14S995, D14S973, D14S1016, and D14S977), and three intragenic single-base-pair polymorphisms (A(669)TG/G(669)TG, C(987)GG/G(987)GG, and TAA(1118)/TAC(1118)). The results show two different haplotypes, specific to the island of origin, in families of Azorean extraction. In families from mainland Portugal, both Azorean haplotypes can be found. The majority of the non-Portuguese families also share the same intragenic haplotype seen in the families coming from the island of Flores, but at least three other haplotypes were seen. These findings suggest two introductions of the mutation into the Portuguese population. Worldwide, the sharing of one intragenic haplotype by the majority of the families studied implies a founder mutation in MJD.

Alleles↗
PubMed2000

Distant enhancers stimulate the albumin promoter through complex proximal binding sites.

The albumin-alpha-fetoprotein locus epitomizes the main features of transcriptional regulation of fetal and adult hepatocyte-specific genes: developmentally regulated promoters and strong distant enhancers. Full enhancer activity required only a proximal albumin-promoter region containing the TATA box, hepatic nuclear factor 1 (HNF1), and nuclear factor Y (NF-Y) sites. Deletion of the HNF1 site abrogated enhancer and promoter activity, whereas methylation of the site reduced all activity by about 3-fold. Deletion of the NF-Y site attenuated activity by about half, but much of the activity could be replaced by juxtaposition of an upstream region (designated distal element IV). Gel shift and competition analysis demonstrated that binding of architectural factors overlapped NF-Y binding. Moreover, a mutation that eliminated NF-Y binding but only minimally perturbed the surrounding region did not affect enhancer function. In plasmids with a second promoter, the enhancers simultaneously stimulated both albumin and alpha-fetoprotein promoters with minimal competition, but surprisingly some mutations in the albumin promoter attenuated expression from both promoters, whereas another uncoupled their expression. With single promoters, the function of the proximal promoter region was controlled by three parameters in the following hierarchy: HNF1 binding > local architecture > NF-Y binding, but integrated two-promoter function had a much greater dependence on NF-Y.

Albumins↗
PubMed2000

Immunophenotypic aberrations, DNA content, and cell cycle analysis of plasma cells in patients with myeloma and monoclonal gammopathies.

We describe the immunophenotypic and gross DNA defects in 55 patients with myeloma and 50 patients with monoclonal gammopathy and review the literature on this subject (MedLine, 1994-2000). Our data confirmed previous reports indicating that in myeloma nearly all marrow plasma cells are abnormal (98.7 +/- 8.1%). In monoclonal gammopathy the fraction of abnormal plasma cells was 35.0 +/- 32.8%. In both myeloma and monoclonal gammopathy, the most frequent aberrant phenotypic features consisted of absence of expression of CD19, strong expression of CD56, and decreased intensity of expression of CD38; aberrant expression of CD10, CD20, CD22, or CD28 was observed in less than one-third of myeloma cases. The vast majority of cases had two or more phenotypic aberrations. In the DNA studies, 7% of myeloma cases were biclonal and 93% of cases were monoclonal. In those studies with only one plasma cell mitotic cycle, 37% had normal DNA content and 63% were aneuploid (hyperploid, 61%; hypoploid, 2%). The mean percentages of plasma cells in S- and G2M phases were 4.9 +/- 8.5 and 4.4 +/- 6.9%, respectively. Thirty-eight percent of cases had more than 3% of plasma cells in S phase. In monoclonal gammopathy, the DNA index of abnormal plasma cells ranged from 0.89 to 1.30 and the percentage of diploid (31%) and aneuploid (69%) cases was not different from the results found in myeloma. The differences in percentage of abnormal plasma cells in S- (7.4 +/- 8.6%) and G2M-phases (2.4 +/- 1.7%) in patients with monoclonal gammopathy were not statistically significant.

Adult↗
PubMed2000

Recurrent posttraumatic urethrovaginal fistula: a new application for ASTRA.

The authors describe the results of an application of the surgical technique called ASTRA (anterior sagittal transrectal approach) in the case of a 16-year-old girl with a posttraumatic urethrovaginal fistula. The young girl with a posttraumatic urethrovaginal fistula had recurrence after 4 surgical attempts at closure performed by the vaginal approach before it was definitively corrected with the ASTRA. Two years after the ASTRA operation the patient is well with a complete restitution of function confirmed by a voiding cystourethrogram and urodynamic and rectal manometric tests. The successful recovery confirmed that ASTRA may be an excellent method of treating the developmental or acquired anomalies of the perineal region.

Adolescent↗
PubMed2000

Cardiocirculatory changes during videolaparoscopy in children: an echocardiographic study.

We examined cardiovascular changes associated with intra-abdominal insufflation in 20 children (mean age 6.1+/-4.7 years, ASA physical status I or II) undergoing laparoscopic surgery with general anaesthesia using echocardiography with a transthoracic approach. Intra-abdominal pressure never exceeded 10 mmHg. Systolic blood pressure, diastolic blood pressure, endtidal CO2, peak, and mean airway pressure increased during intra-abdominal insufflation (P < 0.001). Pneumoperitoneum was associated with increases (P<0.001) in left ventricular enddiastolic volume, left ventricular end-systolic volume and left ventricular endsystolic meridional wall stress. In addition, before, during and after intra-abdominal insufflation, left ventricular fractional shortening and left ventricular ejection fraction, underwent slight, insignificant changes. Pneumoperitoneum in children has a major impact on cardiac volumes and function, mainly through the effect on ventricular load conditions. The sharp increase in intra-abdominal pressure affects both preload and afterload, while systolic cardiac performance remains unchanged.

Anesthesia, General↗
PubMed2000

Laparoscopic repair of Morgagni-Larrey hernia in a child.

Primary laparoscopic repair of Morgagni-Larrey hernia has been described in adult patients but not in children. This is the first report of primary laparoscopic correction in the pediatric age group without using a prosthesis. A Morgagni-Larrey hernia was found incidentally in a 3-year-old-girl. Laparoscopic correction of the defect was performed. After 6 months the patient is doing well. The chest radiograph shows complete resolution of the hernia. The laparoscopic approach allowed repair the hernia with minimal invasiveness. Laparoscopic correction is not difficult except for those hernias in which dense adhesions are present.

Child, Preschool↗