Non-seasonality of births in Tierra del Fuego (Chile)

Tierra del Fuego is situated at the southern tip of the American continent, which conditions its environmental and climatic characteristics. The colonizing population arrived, at the end of the 19th century, from other Chilean regions (particularly from Chiloe) and diverse European countries, especially Britain and Croatia, but also Germany, Spain and Italy. In the present study, the existence of a seasonal pattern in 5430 births registered in the Chilean population of Tierra del Fuego from 1890 to 1995 was analysed. The analysis showed no seasonal distribution of births in the periods 1890-1920 and from 1946 to the present day, a phenomenon rarely reported in the literature. The absence of seasonality in birth distribution could be related to the great diversity in the origins of the population's families, the constant renovation of this and the declining importance of the administrative capital of the province of Tierra del Fuego, Porvenir, in favour of Punta Arenas, capital of the Magellanic region. In the period of maximum development of the capital of the province, a seasonal pattern was detected with a peak in April and a trough in October, which corresponds with a maximum of conceptions in July and, in general, during the early southern winter and a decline in births from late spring to mid-summer, with a trough in January. This birth distribution is interpreted as a subordination of activity and social life to the annual sheep cycle. In addition to temporal trends, the influence on the observed patterns of environmental parameters, father's occupation, seasonality of marriage and the origin of the parents were analysed.     

MR imaging assessment of juxta cortical edema in osteoid osteoma in 28 patients

Osteoid osteoma (OO) is a benign skeletal neoplasm. Twenty-eight patients with proven OO were studied with MRI regarding soft tissue involvement which was diagnosed when high proton-density and T2-weighted signal intensity and low signal intensity on T1-weighted images were found close to bone. Most tumors were located in the femur and tibia; 6 cases diaphyseal, 12 metaphyso-diaphyseal, and 10 epiphyseal. In relation to the cortex, 15 were located centrally or in its outer margin. Soft tissue involvement was found in 15 patients (53.6 %). A statistical relationship was found between soft tissue involvement and the tumor's location with regard to the cortex, being more frequent in peripherally located tumors. Therefore, soft tissue involvement is a frequent finding in peripherally located OO. Received 30 December 1996; Revision received 21 April 1997; Accepted 16 June 1997     

Secretory antibody directed against rotavirus in human milk--measurement by means of enzyme-linked immunosorbent assay.

Human milk contains antibodies to a variety of enteropathic agents. We utilized the method of enzyme-linked immunosorbent assay to investigate anti-rotavirus secretory IgA in 113 human milk and colostral specimens from a rural area in Guatemala, 32 colostral specimens from an urban area of Costa Rica, and 12 from an urban area of the United States. Anti-rotavirus SCIgA was found in all colostral samples and in 94% of the milk specimans. Both the absolute concentration of anti-rotavirus SCIgA and concentration relative to total SCIgA were highest in colostrum, falling to lower but detectable levels from one week to two years after birth. No significant differences were noted in the results from the specimens from the three different geographic areas. The possible role of this antibody in immunity to rotavirus infections is discussed.     

Differences in genetic changes between multiple myeloma and plasma cell leukemia demonstrated by comparative genomic hybridization.

To analyze the genomic differences between multiple myeloma (MM) and plasma cell leukemia (PCL), a total of 30 cases were studied by comparative genomic hybridization (CGH). In five cases with a low proportion of plasma cells (PC) in bone marrow, an enrichment of PC was performed by using immunomagnetic beads conjugated with the monoclonal antibody B-B4. In 24 out of the 25 MM (96%) and in all five PCL (100%) patients DNA copy number changes were identified by CGH analysis; in the MM case without chromosomal imbalances, the immunomagnetic enrichment of PC had failed. The most recurrent changes in MM patients were gains at chromosomes 15q (48%), 11q (44%), 3q (40%), 9q (40%) and 1q (36%). By contrast, all PCL patients showed gains in 1q. Losses of chromosomal material were significantly more frequent in PCL than in MM patients (P = 0.03): losses on 13q in 80% of PCL vs 28% of MM; and on chromosome 16 in 80% vs 12%, respectively. In addition, PCL patients showed losses of 2q and 6p that were not present in MM. The CGH data show differences in chromosomal imbalances between MM and PCL.     

Prevalence of gestational diabetes mellitus: variations related to screening strategy used

OBJECTIVE: To determine the prevalence of gestational diabetes mellitus in a large general obstetric population and its variations depending on the presence of risk factors, and to evaluate how the gestational diabetes screening strategies applied might modify the observed prevalence in the population. DESIGN: A retrospective cohort study. METHODS: The study population was a total of 2574 pregnant women. Information about risk factors, screening and diagnosis of gestational diabetes was obtained. Frequency of risk factors under the American College of Obstetrics and Gynecologists (ACOG) and the American Diabetes Association (ADA) criteria, and observed and expected prevalence of gestational diabetes mellitus were calculated and compared for statistical significance. RESULTS: Age > or = 30 years, family history of diabetes, obesity and previous fetal macrosomia were the most frequent risk factors. Under ACOG recommendations, 45% of our general obstetric population would have been exempt from gestational diabetes mellitus screening, as compared with only 15.5% under ADA guidelines. Sixty-five patients were diagnosed as having gestational diabetes mellitus, giving an overall prevalence of 2.5% (confidence interval 2.0-3.2). Among the low-risk women, prevalence values were 0.6% and 0.5% respectively under ACOG and ADA criteria, whereas for those presenting one or more risk factors rates were 4% and 2.9% respectively. CONCLUSIONS: In our general obstetric population, gestational diabetes mellitus prevalence was found to be approximately six times lower among low-risk gravidae than among the high-risk subjects, suggesting that selective screening might be beneficial. Nevertheless, selective gestational diabetes mellitus screening under ADA criteria seems to entail the same disadvantages as the selective screening strategies without any apparent benefits.     

Evidence of nosocomial Stenotrophomonas maltophilia cross-infection in a neonatology unit analyzed by three molecular typing methods.

OBJECTIVE: To characterize the epidemiological relationships among Stenotrophomonas maltophilia isolates in the neonatology unit of our institution over a 4-month period in which an increased number of isolates was observed. SETTING: The neonatology ward in a 2,000-bed university hospital in Madrid, Spain. DESIGN: A retrospective molecular epidemiological analysis using three different typing methods, arbitrarily primed polymerase chain reaction (PCR), pulsed-field gel electrophoresis, and enterobacterial repetitive intergenic consensus-PCR, was performed with 11 isolates obtained from seven neonates over a 4-month period. Presumed unrelated isolates also were included as controls. A similarity dendrogram was obtained, to analyze the genetic relatedness among the isolates. RESULTS: All isolates from the neonates, except one, showed a remarkably high homology among their typing patterns for the three methods assayed and clustered in the relatedness dendrogram at 96% similarity. The unrelated strains selected as controls were unclustered. The index case was considered to be a newborn who had an S. maltophilia isolate from a culture drawn on the day of admission to the neonatology unit and which was included in the clustered similarity group. CONCLUSIONS: Such a high genetic similarity among the isolates, together with the presence of an index case who had been colonized or infected by S. maltophilia before arrival at our institution, constitutes the first evidence of nosocomial cross-transmission of this microorganism.