Genomic analysis of inbreeding level, kinship and breed relationships in Creole cattle from South America.

The conservation of animal genetic resources refers to measures taken to prevent the loss of genetic diversity in livestock populations, including the protection of breeds from extinction. Creole cattle populations have suffered a drastic reduction in recent decades owing to absorbent crosses or replacement with commercial breeds of European or Indian origin. Genetic characterization can serve as a source of information for conservation strategies to maintain genetic variation. The objective of this work was to evaluate the levels of inbreeding and kinship through the use of genomic information. A total of 903 DNAs from 13 cattle populations from Argentina, Bolivia and Uruguay were genotyped using an SNP panel of 48 K. Also, a dataset of 76 K SNPs from Peruvian Creole was included. Two inbreeding indices (FROH and Fhat2) and kinship relationships were calculated. In addition, effective population size (Ne), linkage disequilibrium, population composition and phylogenetic relationships were estimated. In Creole cattle, FROH ranged from 0.14 to 0.03, and Fhat2 was close to zero. The inferred Ne trends exhibited a decline toward the present for all populations, whereas Creole cattle presented a lower magnitude of Ne than foreign breeds. Cluster analysis clearly differentiated the taurine and Zebu components (K2) and showed that Bolivian Creole cattle presented Zebu gene introgression. Despite the population reduction, Creole populations did not present extreme values of consanguinity and kinship and maintain high levels of genetic diversity. The information obtained in this work may be useful for planning conservation programmes for these valuable local animal genetic resources.

Diversity of Acanthocephala parasites in Neotropical amphibians.

Acanthocephalans constitute a small taxonomic group related to rotifers and specialized in a parasitic lifestyle. Anurans act as paratenic and definitive hosts and infections always occur trophically. Our objective is to describe and summarize the richness of acanthocephalans in Neotropical anurans. We conducted a literature review in the main research databases, compiling data published until August 2021. We identified 66 articles with records of acanthocephalan-anuran association, 53.03% were carried out in Brazil. We detected 108 species of anurans from 11 families parasitized by acanthocephalans. With the exception of Bufonidae, Hylidae and Leptodactylidae, which are relatively well-studied families, interaction with acanthocephalans remains largely unexplored for most anuran species. We found six families of acanthocephalans: Centrorhynchidae, Echinorhynchidae, Oligacanthorhynchidae, Cavisomidae, Neoechinorhynchidae and Plagiorhynchidae. Centrorhynchidae and Echinorhynchidae presented the largest number of taxa associated with anurans. The largest number of records corresponded to acanthocephalans in the larval stage (cystacanths), for which anurans act as paratenic hosts. We observed a lack of specific taxonomic resolution in the identifications of most reports, because a large part of the records in the larval stage make morphological identification difficult. Brazil, Mexico, Paraguay, Argentina, Ecuador and Peru are the countries with the most records, while Costa Rica, Venezuela, Colombia, Chile and Uruguay exhibited the lowest publication numbers, resulting in gaps in the distribution of acanthocephalans. We expanded the known number of anuran species parasitized by acanthocephalans, compared to the last published review. Overall, we aim to contribute to the understanding of diversity within this intriguing but understudied group.

Concordancia inter e intraobservador en la medida de los agujeros maculares por tomografía de coherencia óptica / Inter- and intra-observer agreement in the measurement of macular holes by optical coherence tomography

Antecedentes y objetivo El agujero macular de espesor completo (AMEC) es una lesión foveal causada por un defecto del espesor completo de la retina neurosensorial. En su diagnóstico y en la indicación de tratamiento quirúrgico se tiene en cuenta la medida del agujero según la herramienta proporcionada por la OCT. Dicha medida puede ser realizada por varios oftalmólogos a lo largo del seguimiento de un paciente. El objetivo de este estudio es averiguar si existe variabilidad intraindividual e interindividual en dichas mediciones. Material y métodos Revisión retrospectiva de imágenes de b-scans de OCT con diagnóstico de AMEC. Se realizaron mediciones del diámetro mínimo del AMEC mediante la herramienta manual disponible en el DRI-Triton (Topcon, Japón) en las escalas 1:1 y 1:2, en días diferentes, por 2 especialistas en retina y 2 residentes. Se compararon dichas mediciones para valorar la correspondencia interobservador e intraobservador Resultados Se analizan 34 imágenes. Para la variabilidad intraobservador se obtuvo un índice de correlación superior a 0,98 en todos los casos. Para la variabilidad interobservador, el coeficiente de correlación intraclase fue de 0,94 (IC del 95%, 0,91-0,97) para la escala 1:1, y de 0,94 (IC del 95%, 0.91-0,97) para la escala 1:2. Conclusiones Los valores del tamaño de los AMEC medidos por OCT son reproducibles entre oftalmólogos especialistas y residentes y son independientes de la escala de la imagen en la que se realice dicha medición (AU)

Background and objective A full-thickness macular hole (FTMH) is a foveal lesion caused by a defect in the full thickness of the neurosensory retina. Its diagnosis and the indication for surgical treatment take into account the measurement of the hole according to the tool provided by the OCT. This measurement can be performed by several ophthalmologists during the follow-up of a patient. The aim of this study is to find out whether there is intra-individual and inter-individual variability in these measurements. Material and methods Retrospective review of OCT b-scan images with a diagnosis of FTMH. Measurements of the minimum diameter of the FTMH were performed using the hand-held tool available on the DRI-Triton (Topcon, Japan) at 1:1 and 1:2 scales, on different days, by 2retina specialists and 2residents. These measurements were compared to assess inter-observer and intra-observer correspondence. Results Thirty-four images were analysed. For intra-observer variability, a correlation index higher than 0.98 was obtained in all cases. For inter-observer variability, the intra-class correlation coefficient was 0.94 (95% CI: 0.91-0.97) for the 1:1 scale, and 0.94 (95% CI: 0.91-0.97) for the 1:2 scale. Conclusions OCT-measured AMEC size values are reproducible between ophthalmic specialists and residents and are independent of the imaging scale at which the measurement is made (AU)

Response of cows with osteomalacia grazing sub-tropical native pastures to phosphorus supplementation with loose mineral mix or feed blocks.

Osteomalacia outbreaks often occur in cattle grazing native pastures in regions with endemic phosphorous (P) deficiency. This study evaluated the responses of two groups of cows, initially with clinical signs of chronic P deficiency, to P supplements (100 g P/kg) offered ad libitum for 13 weeks as a loose mineral mix (LMM group) or the same mineral mix offered as blocks (BMM group). Half of the cows in each group were categorized as 'with' or 'without' severe osteopenia according to a test that depended on the resistance to penetration of a needle through the left lateral process of the L4-L5 lumbar vertebra. The groups grazed two paddocks that were switched each 3 weeks. The liveweight, supplement intakes, and the P-concentrations in soil, forage, blood, and external cortical bone (ECB) of the ribs were measured. The bicarbonate-extractable P in soil was 3.5 mg/kg. The mean of total P in forage (0.95 g/kg/DM), inorganic P in serum (iP, 0.96 mmol/L), and total P in the ECB of the ribs (85 mg/mL) at the beginning of the experiment were all low and consistent with severe chronic P deficiency. The P supplementation allowed clinical recovery in 18/20 cows with their serum and ECB P and calcium approaching normal values and in the two remaining cows the only sign was abnormal gait. Cows consumed more of the LMM than BMM supplement (means 8.3 and 6.6 g P/day, respectively). After 13 weeks cows initially classified as 'with severe osteopenia' and supplemented with LMM had higher (P < 0.05) final liveweight (difference = 21.6 kg), iP (difference = 0.74 mmol/L), bone Ca (difference = 65.7 mg/mL) and bone P (difference = 26.5 mg/mL) concentrations and lower (P < 0.01) final serum Ca/iP ratio (difference = -0.65) than cows with severe osteopenia but supplemented with BMM. The treatment of severe P deficiency cows grazing P deficient sub-tropical grasslands by P supplementation for 13 weeks was more effective with LMM than BMM.

Analysis of Doberman Pinscher and Toy Poodle samples with targeted next-generation sequencing.

Next-generation sequencing (NGS) technologies have enabled the identification of many causal variants of genetic disorders, the development of parentage tests and the analysis of multiple traits in domestic animals. In this study, we evaluated the performance of a Canine Targeted Genotyping-by-Sequencing (GBS) custom panel (Thermo Fisher Scientific, Waltham, Ma, USA) in a cohort of 95 dog DNA samples, comprising 76 Doberman Pinschers and 19 Toy Poodles from Argentina. The used panel included 383 targets (228 parentage SNVs, 137 genetic disorder markers and 18 trait markers). While paternity analysis showed correct duo (97.4%; LOD > 2.98E+13) and trio (100%; LOD > 2.20E+15) parentage assignment, the panel resulted still insufficient for excluding close relatives in inbred populations. In this sense, close relatives were wrongly assigned as parents in 12.6% of duos and 0.3% of trios. We detected 17 polymorphic markers (genetic disorders, n = 4; hair type, n = 3; coat color, n = 10) and estimated their allele frequencies in the studied breeds. The accuracy of targeted GBS results were evaluated for three markers that were associated with Progressive rod-cone degeneration, von Willebrand disease type 1 and dilated cardiomyopathy by pyrosequencing and Sanger sequencing genotyping, showing 94-100% concordance among assays. The targeted GBS custom panel resulted cost-effective strategy to study the prevalence of genetic disorders and traits in a large number of samples and to analyze genetic interactions between previously reported variants. Once assays based on AgriSeq technology were standardized, their uses are a good strategy for large-scale routine genetic evaluation of animal populations.

Evolución cognitiva en la etapa escolar de un grupo de niños con retraso global del desarrollo / Cognitive evolution in the school stage of a group of children with global developmental delay

Introducción: Existen pocos estudios sobre la evolución del retraso global del desarrollo (RGD), por lo que se cuestiona su valor pronóstico. Objetivo: Describir la evolución cognitiva en la edad escolar de niños con diagnóstico inicial de RGD. Pacientes y Métodos: Estudio observacional, transversal, con análisis prospectivo y retrospectivo. Fueron incluidos niños de seis a once años de edad, con diagnóstico previo de RGD. La variable punto final fue la presencia o no del déficit cognitivo (menor a dos desvíos estándares en las pruebas cognitivas), se realizó análisis con el paquete estadístico R. Resultados: Se estudiaron 150 pacientes con diagnóstico inicial de RGD, 86 con compromiso leve y 64 moderado-severo. El déficit cognitivo persistió en 75 pacientes (50%), 34.8% en el grupo leve y 70.3% en el moderado-severo Del resto, un 13% tuvo rendimiento promedio, un 20%, limítrofe y el 17% perfil discrepante. El análisis univariado identificó cuatro factores de riesgo asociados a persistencia del compromiso cognitivo: el grado de compromiso inicial moderado/severo (OR 4,59, 2,24-9,78), el tiempo de tratamiento menor a tres años (OR 2,30 1,02-5,34), las necesidades básicas insatisfechas (OR 1,62 0,76-3,47) y la presencia de síndrome genético (OR 2,99 1,09-8,99). El modelo de regresión logística con mayor poder explicativo incluyó estas cuatro variables (p 0.9998). Conclusiones: La trayectoria cognitiva mostró un 50 % de persistencia del déficit cognitivo. El grado de compromiso inicial, la duración del tratamiento, las necesidades básicas insatisfechas y la presencia de un síndrome genético asociado mostraron asociación con la persistencia del mismo (AU)

Introduction: Studies on the outcome of global developmental delay (GDD) are scarce, and therefore, their prognostic value is questionable. Objective: To describe the cognitive outcome at school age of children initially diagnosed with GDD. Patients and Methods: Cross-sectional, observational study with a prospective and retrospective analysis. Children between six and 11 years of age with a previous diagnosis of GDD were included. The endpoint variable was the presence or not of a cognitive deficit (two standard deviations below the mean on cognitive tests). Analyses were performed using the R Statistical Software. Results: 150 patients with an initial diagnosis of GDD were studied, 86 with mild and 64 with moderate-to-severe involvement. The cognitive deficit persisted in 75 patients (50%); 34.8% of whom were in the mild and 70.3% in the moderate-to-severe group. Of the remaining patients, performance was average in 13%, borderline in 20%, and the profile was discrepant in 17%. Univariate analysis identified four risk factors associated with persistence of the cognitive deficit: initial moderate-to-severe degree of the deficit (OR 4.59, 2.24-9.78), treatment duration less than three years (OR 2.30, 1.02-5.34), unsatisfied basic needs (OR 1.62, 0.76- 3.47), and presence of a genetic syndrome (OR 2.99, 1.09-8.99). The logistic regression model with the strongest explanatory power included these four variables (p 0.9998). Conclusions: In 50% the cognitive course showed a persistent cognitive deficit. The degree of initial compromise, treatment duration, unsatisfied basic needs, and presence of a genetic syndrome were associated with persistence of the deficit. (AU)

A pilot study describing physical activity in persons with schizophrenia spectrum disorders (SSDS) after an exercise program.

Despite the well known mental and physical health benefits of exercise, persons with schizophrenia spectrum disorders remain sedentary. While the exercise barriers (i.e., lack of motivation, poor concentration, sedative effects of medication, poverty, and lack of access to exercise education/programs) of persons with SSDs are numerous, lack of motivation is considered foremost among them. Exercise interventions have been shown to improve exercise behavior, but there is a need for longitudinal documentation of physical activity after interventions conclude. This pilot study describes the physical activity level of 22 persons with SSDs 14 to 34 (mean 22) months after the conclusion of an exercise intervention provided in a randomized controlled trial (RCT). Eighteen months after the RCT, 22 participants wore pedometers daily for one week without altering their activity. Experimental participants walked more steps and covered more distance on average than control participants on six of the seven days. This pilot study is among the first to document the physical activity level of persons with SSDs after exercise intervention. While our findings confirm the low activity level of persons with SSDs reported by others, experimental participants demonstrated higher activity levels than controls on most days. Future studies should increase the sample size and recruit participants from multiple sites to enhance power and generalizability.

Tumores odontogénicos a células fantasmas. Conceptos actuales y aporte de 10 nuevos casos / Odontogenic tumours ghost cell tumors. Actual concepts and reports of 10 new cases

Se presentan 10 nuevos casos de neoplasias odontogénicas a células fantasmas del archivo de la Cátedra de Anatomía Patológica de la Facultad de Odontología de la UDELAR de Montevideo, Uruguay. Estos tumores constituyeron el 0,08% del total de biopsias del Servicio y el 2,9% de todas las neoplasias odontogénicas registradas. Nueve fueron tumores odontogénicos quísticos calcificantes y uno fue tumor dentinogénico a células fantasmas. Ocho casos fueron centrales y dos periféricos (uno, quístico y el otro, sólido).Se registraron las características clínicas, radiográficas e histopatológicas y se compararon con otros trabajos de la literatura internacional (AU)

This paper reports 10 new cases of ghost cell odontogenic tumors retrieved from the files of the Oral Pathology Service of the Faculty of Dentistry (UDELAR), Montevideo, Uruguay. These tumors accounted for 0.08% of total biopsies and 2.9 % of all registered odontogenic neoplasms. Nine cases were calcifying cystic odontogenictumors (CCOT) and one dentinogenic ghost cell tumor (DGCT), eight in central and two in peripheral locations(one cystic and one solid variant).Clinical, radiographic and histopathological features are presented and compared with reported cases in literature (AU)

Delecion 22q11.2: características de un grupo de pacientes atendidos en el Hospital Juan P. Garrahan / 22q11.2 deletions: features of a group of patients seen at the Juan P. Garrahan Hospital

El síndrome de Deleción 22q11.2 afecta el aparato cardiovascular, la inmunidad, las funciones endocrinológicas, la cavidad oral, el desarrollo neurocognitivo, con un fenotipo particular debido a una anomalía cromosómica. Objetivo: evaluar las características clínicas y citogenéticas de pacientes atendidos en forma multidisciplinaria, a través de un estudio observacional, descriptivo, transversal e interdisciplinario de una cohorte en seguimiento. Se diagnosticaron 194 pacientes con microdeleción 22q11.2, M 95/ F 99, con un rango etario: 0 a 192m (4días-16 a) y una mediana: 23m, el signo más constante fue la facies característica que se observó en un 100%, el 72,5% presentó malformación cardiovascular, 74,7% mostró defectos en su cavidad oral y el 30,5% hipoacusias. La mayoría de los pacientes evidenciaron compromiso de su neurodesarrollo en forma global, con retraso y trastorno de lenguaje. Se detectaron alteraciones en la inmunidad en el 64,31% con disminución de los linfocitos T, hipocalcemia en 36,8% y defectos urológicos en un 14,7%. Entre los diagnósticos citogenéticos se observó además dos pacientes con traslocaciones cromosómicos de novo que involucraban la microdeleción y un paciente con la deleción en mosaico. Los estudios parentales evidenciaron un 10% de casos heredados. La población estudiada mostró una clínica y frecuencia de anomalías similar a la referida en la bibliografía a excepción de los trastornos auditivos y urológicos que se vieron con menor frecuencia mientras que la prevalencia de alteraciones neurocognitivas fue mayor. La complejidad y variabilidad del síndrome requiere un manejo multidisciplinario.

22q11.2 deletion syndrome may affect the cardiovascular and immune systems, endocrine functions, the oral cavity, and neurocognitive development with a peculiar phenotype due to the chromosomal anomaly. Objective: To evaluate the clinical and cytogenetic features of patients followed-up by a multidisciplinary team in an observational, descriptive, cross-sectional and interdisciplinary cohort study. We diagnosed 194 patients with a 22q11.2 microdeletion, M 95/ F 99, with an age range of 0 to 192 months (4 days-16 years) and a me-dian age of 23 months. Characteristic facies was observed in 100% of the patients, cardiovascular malformation in 72.5%, oral cavity abnormalities in 74.7%, and hearing loss in 30.5%. The majority of the patients showed global impairment of neurological development, such as developmental delay and language disorders. Alterations in the immune system with a low T-lymphocyte count were found in 64.31% of the patients, hypocalcemia in 36.8%, and urinary abnormalities in 14.7%. Among the cytogenetic diagnoses, two patients were found to have de novo chromosome translocations involving the microdeletion and one patient had a mosaic deletion. Stud-ies in parents showed that the disease was inherited in 10% of the cases. Clinical findings and rate of anomalies in the study population were similar to those reported in the litera-ture, except for hearing loss and urinary disorders that were less frequently found, while the prevalence of neurocognitive impairment was higher. The complexity and variability of the syndrome warrants a multidisciplinay approach.

The relationship between daily steps and body composition in postmenopausal women.

PURPOSE: The purpose of this study was to examine the relationship between pedometer-determined physical activity (PA) measured in steps per day and adiposity in postmenopausal women. METHODS: Ninety-three women aged 60.9 +/- 5.8 years participated in the study. Relative body fatness was determined by the measurement of height, body mass, percent body fat, trunk fat, and waist and hip circumference. Each subject wore a pedometer for 14 days after testing to measure daily steps. Correlation coefficients were calculated to examine the relationship between average steps per day and adiposity variables. Subjects were grouped according to PA tertiles. ANCOVA, with age as the covariate, was used to determine whether adiposity varied across activity groups. RESULTS: Significant inverse associations (p < 0.001) were found between average steps per day and all adiposity variables (r ranging from -0.487 to -0.368). Relationships remained significant after controlling for the influence of age and caloric intake. Also, there was a significant difference in adiposity variables among PA tertiles, with higher values found in the less active groups. CONCLUSIONS: We demonstrated that postmenopausal women who take more daily steps have more favorable adiposity profiles. Additionally, the average body mass index (BMI) of the women in the active category (accumulating an average of 10,023 +/- 240 steps per day) was in the recommended range (24.1 +/- 0.9 kg/m(2)).

Mitotic polyploidization in trophoblast giant cells of the alpaca.

Genome multiplication is a typical feature of trophoblast giant cell (TGC) development in many species. Elevated nuclear DNA contents can be achieved by modified cell cycles with a complete lack of mitosis (endoreduplication) or with incomplete mitoses. The aim of this study is to characterize genome multiplication in the alpaca TGC. Placental tissues of gestation days 150, 264 and 347 (near term) and term placentae were processed for light microscopy and for transmission electron microscopy. Each TGC showed many nuclear profiles. Observation of serial sections revealed that TGCs are truly multinucleate with several highly lobulated nuclei. Feulgen staining showed that TGC nuclei have a higher DNA content than nuclei of other trophoblast cells. The number of argyrophilic nucleolar organizer regions (AgNORs) in nuclear profiles of TGC was between 15 and 100, while other trophoblast cells showed 1 or 2 AgNORs. Large multipolar mitotic figures with maximal diameters of 80 mum were observed in the alpaca placentas on gestation days 264 and 347. No cytokinesis was seen in TGC. The results show that the mode of genome multiplication in the alpaca TGC is mitotic polyploidization. Subsequent acytokinetic mitoses may lead to an accumulation of chromosomes and centrioles in TGC. With increasing ploidy levels, the shape of these polyploidizing mitoses becomes more irregular. The restitution of nuclei after these complex multipolar mitoses is likely to result in the irregular nuclear shape in TGC.

Developmental changes at the materno-embryonic interface in early pregnancy of the alpaca, Lamos pacos.

This study analyses the manner in which trophoblast cells adhere to uterine epithelium and the subsequent interactions that contribute to the establishment of epitheliochorial placentation in the alpaca Lama pacos. Specimens at the luteal and follicular phases and at 22, 26, 30 and 45 days of pregnancy (op) were processed for morphological studies. On day 15 op, the blastocysts are completely free within the uterine lumen, with implantation starting around day 20. On days 22 and 26 of gestation, the trophoblast is apposed to the epithelial surface of the uterus, with areas of contact and adhesion by means of complex interdigitation. Implantation sites occur prevalently in the left uterine horn, but an expanded trophoblast also occupies large extensions of the right horn, where the maternofetal interaction shows peculiar areas of apposition. As development continues, attachment areas become more extensive. On days 30 and 45, many secretory granules can be seen in the uterine epithelium, while giant multinucleate cells appear interposed between the remaining trophoblast cells, showing intense alkaline phosphatase activity, deposits containing iron and PAS-positive granules. Placental lactogen hormone is not present within the cytoplasm of the binucleate or multinucleate trophoblast cells. By day 30 of gestation, the trophoblast layer is lined by an extraembryonic connective tissue that by day 45 is well vascularized, thus indicating the starting point of placental formation. Fetal and maternal capillaries indent the epithelium and the trophoblast, narrowing the specialized areas of exchange, which occur along the entire maternofetal interface, characterizing the diffuse nature of this placenta.

Dietary antioxidants and lung cancer risk: a case-control study in Uruguay.

To examine the protective role of dietary antioxidants (carotenoids, vitamin C, vitamin E, glutathione, and flavonoids) in lung cancer risk, a case-control study involving 541 cases of lung cancer and 540 hospitalized controls was carried out in Uruguay. The relevant variables were energy adjusted using the residuals method and then categorized in quartiles. Adjusted odds ratios (ORs) for antioxidants were calculated through unconditional logistic regression. With the exception of lycopene and vitamin C, the remaining antioxidants were associated with significant reductions in risk of lung cancer. Of particular interest was the inverse association between dietary glutathione and lung cancer [OR of quartile with highest intake compared with lowest quartile = 0.42, 95% confidence interval (CI) = 0.27-0.63]. Also, carotenoids and vitamin E were associated with significant reductions in risk of lung cancer (OR = 0.43, 95% CI = 0.29-0.64 for total carotenoids and OR = 0.50, 95% CI = 0.39-0.85 for vitamin E). A joint effect for high vs. low intakes of beta-carotene and glutathione was associated with a significant reduction in risk (OR = 0.32, 95% CI = 0.22-0.46). It could be concluded that dietary antioxidants are associated with a significant protective effect in lung carcinogenesis and that the inverse association for glutathione persisted after controlling for total vegetables and fruits.

Inferencia de parametros estadisticos de los grupos sanguineos O A B y el factor Rh en el departamento de Cochabamba / Statistical parameters of blood groups O, A, B and factor Rh in Cochabamba

Se determinaron los grupos sanguineos O, A, B y el FactorRh en 20.611 personas del departamento de Cochabamba. Se tomaron muestras dirigidas de diversas areas geograficas habitadas por grupos poblacionales de distinta influencia racial y de areas autoctonas. Se hicieron comparaciones e inferencias de los datos obtenidos entre la poblacion de la ciudad de Cochabamba,las provincias, las poblaciones autoctonas (tribus de los Yuracares) y los datos proporcionados por el Autor A. Guyton en el libro Fisiologia Medica y el autor B., Houssay en el libro Fisiologia Humana. La distribucion de los datos finales es: Grupos sanguineos ( por ciento ): O:74.6; A:19.3; B:5,2; AB:0,9. Factor Rh: Positivo 98,9; Negativos: 1,1

Spectral alterations in Rhodobacter capsulatus mutants with site-directed changes in the bacteriochlorophyll-binding site of the B880 light-harvesting complex.

Site-directed mutagenesis has suggested that conserved histidine and alanine residues in the alpha-subunit of the B880 (LHI) antenna complex of Rhodobacter capsulatus (alpha His32 and alpha Ala28) form part of the bacteriochlorophyll binding site (Bylina, E.J., Robles, S.J. and Youvan, D.C. (1988) Isr. J. Chem. 28, 73-78). Spectroscopic characterization of chromatophores from alpha Ala28 mutants at 77 K revealed: (i) red shifts in B880 absorption and emission maxima of approximately 6 and 10 nm, respectively, with a serine exchange; (ii) red shifts of 3 nm with a glycine exchange; (iii) and no significant shifts with a cysteine exchange, despite a reduction of approximately 50% in B880 level. The strains with the serine and glycine exchanges showed characteristic fluorescence polarization increases over the red-edge of the B880 band, suggesting that the absorption red shifts arose from altered pigment-protein interactions rather than from increased oligomerization states that would be expected to show markedly diminished and red shifted rises in polarization (Westerhuis, W.H.J., Farchaus, J.W. and Niederman, R.A. (1993) Photochem. Photobiol. 58, 460-463). Excitation spectra of strains with alpha His32 to glutamine and alpha Ala28 to histidine exchanges, thought to be depleted in B880, revealed low levels of a 'pseudo-B880' complex with blue-shifted maxima and fluorescence polarization rises; when excited directly into this component, the former strain showed an emission spectrum similar to that of B880. An essentially wild-type electrochromic carotenoid response was observed only in the B880-containing mutants, since membranes isolated from the B880-depleted strains exhibited an increased permeability to ions.

Effects of phospholipase A2 digestion on the carotenoid and bacteriochlorophyll components of the light-harvesting complexes in Rhodobacter sphaeroides chromatophores.

The instantaneous electrochromic response of carotenoids associated with the B800-850 light-harvesting complex of Rhodobacter sphaeroides has been used widely as an intrinsic probe of membrane potential. In the present study, the structural basis for this phenomenon was examined by phospholipase A2 digestion of chromatophores from R. sphaeroides strain NF57G, containing B800-850 as the sole pigment-protein complex. The major phospholipase-induced alterations of the overall carotenoid absorption spectrum were characterized by an absorbance loss and a blue shift that were accompanied by a decrease in absorbance at 800 nm and a red shift in the B850 absorbance band. In wild-type chromatophores, the electrochromic carotenoid response induced by both flash illumination and a K+ diffusion potential was diminished by approximately 60% after 1 h of digestion. The initial loss of the carotenoid response was correlated specifically to the hydrolysis of phosphatidylethanolamine, and was shown to arise from effects exerted directly upon the electrochromically active carotenoid pool, possibly by alterations in the spatial relationship between the field-sensitive carotenoids and the polarizing permanent field. In phospholipase A2-digested NF57G preparations in which the B800 band was diminished by nearly half and the carotenoid response was abolished, no significant changes in the efficiency of energy transfer from carotenoids to bacteriochlorophyll were detected at 77 K, suggesting that the electrochromically active carotenoids are not energetically linked to B800 bacteriochlorophyll.

Grupos sanguineos y el factor Rh en el Departamento de Cochabamba / Blood groups and the Rh factor in the Departament of Cochabamba

Se denominan los grupos sanguineos y factor Rh en 9.817 personas del Departamento de Cochabamba. El estudio que se constituye en la primera parte de uno mas amplio, tomo en cuenta diversas areas geograficas y de distinta influencia racial dentro del mencionado departamento. Los datos obtenidos senalan la siguiente distribucion para los grupos sanguineos 72,6// el O, 20,6// para el A, 5,8// para el B y 1// para el AB. En cuanto al factor RH positivo 98,3// y negativo 1,7//. Los resultados muestran significativas diferencias con la informacion referida a paises europeos y del norte del Continente Americano.

Laryngeal cancer in Uruguay (1958-1981). An epidemiologic study.

According to international comparative data on age-adjusted death rates, male mortality caused by laryngeal cancer in Uruguay is ranked second in the world. This fact has prompted the authors to study time trends and to perform cohort analysis of all deaths due to larynx cancer during the 1958 to 1981 period. Localization as well was investigated by means of incident cases taken from Registry of the University Hospital (1960-1981). Trend analyses have shown an increase in age-adjusted death rates among men. This was largely due to the older age of patients. Cohort analysis showed a decline in mortality among younger patients. As far as anatomic location is concerned, a marked predominance of supraglottic cancer was observed. This was particularly high among those belonging to the low-income group.