Persistence of costly novel genes in the absence of positive selection.

Many genetic changes that ultimately lead to adaptive evolution come with a short-term cost expressed in terms of reduced survival and reproduction. In the absence of genetic drift, it is unclear how such costly mutations may persist. Here we experimentally demonstrate that parasites can promote the persistence of costly genetic variants. We employed a genetically engineered strain (GMMO) of the bacterium Pseudomonas fluorescens as a model of the acquisition of a new gene either through a major mutation or through horizontal transfer, and examined its persistence in different evolving communities comprising an ancestral strain and a lytic bacteriophage. Whereas competition resulted in the elimination of the GMMO, inclusion of the phage promoted GMMO persistence. We provide evidence for why this effect is due to the differential susceptibility of GMMO and ancestral bacteria to phage.

Experiencia quirurgica en coartación de aorta

La coartacion de la aorta es una defecto obstructivoque constituye el 8 por ciento del total de pacientes portadores de malformaciones cardiacas. En el presente trabajo se estudiaron 42 pacientes sometidos a cirugía por coartación de aorta desde enero de 1986 a noviembre de 1992, comprendidos entre 1 mes y 29 años , 33 hombres (78.5 por ciento) y 9 mujeres (21.5 por ciento), proporción de 3.7:1.0. Anatomicamente se encontró coartación yuxtaductal en 22 pacientes (52.3 por ciento), preductal3 (7.2 por ciento) de itsmo 12 (28.5 por ciento), con hipoplasia de arco 2 (4.8 por ciento), mixta 3 (7.2 por ciento) y coartación de aorta con otros defectos en 29 casos. Se utilizaron como técnicas quirurgicas: La anastomosis en 14 casos(33.4 por ciento), colocación de tubo en 3 (7.1 por ciento), Telles 14 (33.4 por ciento), aortoplasia 11(26.1 por ciento). De todos los pacientes estudiados, únicamente 8 presentaron compliaciones tempranas, 7 con crisis hipertensiva (16.6 por ciento) y 1 sección de conducto toraxico (2.3 por ciento), no se presentaron complicaciones tardias. Se plantea la utilidad de un diagnostico a menor edad e intervención quirurgica temprana.

[Extracorporeal lithofragmentation and of direct contact. Development of mathematical models for calculating the energy and predicting the fragmentation]. / Litofragmentación extracorpórea y de contacto directo. Desarrollo de modelos matemáticos para el cálculo de la energía y la predicción de la fragmentación.

The present experimental 'in vitro' study pursues the development of mathematical equations which, prior to lithofragmentation, would allow to estimate the amount of energy required and to predict the degree of fragmentation for each of the different sources of energy. A total of 114 calculi with 6 different compositions were analyzed by conventional X-rays (Rx), computerized axial tomography (CT) and dual X-ray densitometry (DO). Calculi were then fragmented using 4 different types of energy: electrohydraulic (LEH), piezoelectric (LEP), ultrasounds (US) and pulse laser (LAS). The correlation between imaging techniques parameters on the one side, and the amount of energy used and degree of fragmentation obtained on the other one, allow with a multiple linear regression analysis, both to develop mathematical equations to estimate the amount of energy required, and to predict the fragmentation rate.

Evidence for genetic heterogeneity in hereditary hydronephrosis caused by pelvi-ureteric junction obstruction, with one locus assigned to chromosome 6p.

Hereditary hydronephrosis (MIM 143400) is an autosomal dominant trait that causes unilateral or bilateral pelvi-ureteric junction (PUJ) obstruction. Linkage analysis was undertaken in 5 families with hereditary PUJ obstruction using the major histocompatibility complex locus as a test marker. The data as a whole supported a hereditary hydronephrosis locus on 6p. Maximal lod scores were 3.090 at a recombination fraction of 0.1 with full penetrance, and 2.486 at a recombination fraction of 0.1 with a penetrance of 90%. However, analysis of two point lod scores using the HOMOG program revealed significant evidence for genetic heterogeneity with one locus on 6p in 4 of the families, and a different locus in one family. After exclusion of this unlinked family, two point analysis gave a maximal lod score of 3.9 at a recombination fraction of 0.05 with full penetrance, and 4.2 at a recombination fraction of 0.0 with 90% penetrance. These data support the assignment of one of the loci for hereditary hydronephrosis to chromosome 6p.

Genuine hereditary hydronephrosis in a three-generation family. Clinicopathological and genetic implications with a review of the literature.

The clinical features and management of genuine hereditary hydronephrosis (GHH) in 4 members of the same family are presented. Genealogical studies provide evidence of a dominant autosomal inheritance with complete penetrance. All affected members of the family had inherited the same HLA haplotype through the male line. This finding, added to those from previous association studies with histocompatibility typing (in 3 families), lends support to the localization of the GHH gene/s in the 6p human chromosome. Based on our findings from the present familial study and on a review of the literature, we suggest that all first-degree relatives of children or adults with genuine hydronephrosis should be screened by ultrasound. Such a prospective screening, including fetal echography, will lead to earlier diagnosis and treatment of asymptomatic cases and, moreover, will identify GHH cases for possible genetic counseling with regard to the empiric recurrence risk.

[Xanthogranulomatous pyelonephritis. Retrospective study]. / Pielonefritis xantogranulomatosa (PXG). Estudio retrospectivo.

The incidence of PGX in our setting is low (0.67%). Middle-aged women comprise most of our cases. This disease process is usually unilateral; 53.2% of the present series had right-sided renal involvement. Over the past 17 years, 135 cases of histopathologically-documented XGP have been recorded at our hospital. Sixty-three cases were studied retrospectively. Patient history, symptoms and signs, and data gleaned from physical examination are presented. Similarly, patient outstanding pathogenetic features are described. Preoperative diagnosis of XGP is difficult. The availability of high resolution imaging techniques has enhanced diagnostic accuracy. Urinary cytology permits preoperative diagnosis with an accuracy rate of 80%. The postoperative prognosis is excellent.

Hyperparathyroidism in metastases of prostatic carcinoma: a biochemical, hormonal and histomorphometric study.

Secondary hyperparathyroidism can develop as a result of bone metastases from prostatic cancer, but this has not been studied from the multiple aspects of biochemistry, hormonal status and histomorphometry. In 20 patients with stage-D prostatic cancer, a transiliac bone biopsy was performed for histomorphometric study. In all of them, molecular parathormone (PTH-M) and osteocalcin were determined by radioimmunoassay together with other parameters considered to be biological markers of bone remodelling. Of these 20 patients, only 2 (10%) had elevated PTH-M (240 +/- 20.6 pmol/l), differing significantly from the other 18 (58.6 +/- 11.7 pmol/l) and from controls (60.4 +/- 7.2 pmol/l). In the high PTH-M patients, corrected calcium was low (7.8 +/- 0.4 mg/dl) as compared to normal PTH-M patients (9.2 +/- 0.5 mg/dl, p less than 0.001), and this was also the case for serum phosphorus (2.2 +/- 0.6 vs. 3.2 +/- 0.3 and 3.4 +/- 0.4 mg/dl, respectively p less than 0.001). Alkaline phosphatase was raised in the patient groups as compared to controls (p less than 0.001) and was higher in the high PTH-M group (362 +/- 58 vs. 224 +/- 62 U/l, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Osteocalcin, parathormone and hypercalciuria.

Osteocalcin synthesis is dependent on the influence of the renal vitamin D metabolite, 1,25(OH)2D3. This metabolite is an etiological factor in some hypercalciurias, and osteocalcin may thus be a parameter for discovering them. In turn, parathormone, which stimulates 1,25(OH)2D3 synthesis, is also implicated in the hypercalciurias. Mean molecular parathormone, osteocalcin, 24-hour calciuria and the calcium/creatinine and hydroxyproline/creatinine ratios were determined in urine samples obtained after a 12-hour fast from 18 patients with absorptive hypercalciuria and 11 patients with renal hypercalciuria out of a total of 62 patients with renal lithiasis. No changes were observed in osteocalcin or parathormone, indicating that neither is valid for the diagnosis of hypercalciuria. Significant differences were only found in the Ca/Cr ratio (p less than 0.001), which was higher (0.31 +/- 0.07 vs. 0.13 +/- 0.04 mg/mg) in renal hypercalciuria than in absorptive hypercalciuria. No changes in osteocalcin have been reported in the hypercalciurias, but variations in parathormone have been reported, therefore requiring further study and thought to understand the processes involved.