Biomedical subjects
Publications and source records attributed to J A Pérez.
Allele frequencies for 18 STR autosomal loci (D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820, D16S539, TH01, TPOX, CSF1PO, Penta D, Penta E, D19S433, D2S1338 and SE33) were obtained from a sample of 191-500 unrelated individuals from Costa Rica, Central America.
We analyzed preoperative factors related to postoperative mortality after liver transplantation among a cohort of 268 consecutive liver transplant patients over 6 years. We studied the impact of 10 recipient variables, 14 donor features, and three operative aspects. We also studied the correlation with death and survival using various predictive scores (Child, Cordoba Score, MELD, and UCLA). Univariate analysis showed that the factors with a significant association with postoperative mortality were the use of noradrenaline in the donor, total ischemia time (>12 hours), and transplant indication (hepatitis C virus versus the rest). Multivariate analysis of mortality showed the impact of female donor sex, recipients over >60 years, recipient albumin less than 2.8, and total graft ischemia time more than 12 hours. Univariate analysis of 1-year survival showed a statistically significant relation with D/R gender similarity, as well as donor GOT (>170) and GPT (>140) values. Multivariate analysis of 1-year survival showed donor GOT (>170) and donor/recipient gender similarity to be significant. Concerning the prediction models, Child-Pugh (AB versus C) best determined postoperative mortality (P < .006), MELD was predictive of 1-year survival (P < .03). The most important variables related to postoperative mortality were total ischemia time over 12 hours, recipient albumin less than 2.8, and age above 60 years. The variable with most impact on 1-year survival was the degree of graft hepatocyte lesion as determined by GOT. The Child-Pugh system is still the best indicator of postoperative mortality, although MELD may also be a good predictor of survival.
1. On a private property with a stable population of wild red-legged partridge (Alectoris rufa) and an appropriate habitat for the survival of the species, reinforcement repopulations were carried out in the months of October and November for two consecutive years using 5- to 6-month-old birds reared on a commercial game farm. 2. Of the 36 released birds, none was still alive by the following spring's breeding period. Mean survival time was 9.4 d in the first year and 7.6 d in the second year. 3. Seventy-two per cent of mortality was attributable to predation, 11% to hunting and 17% to doubtful causes of death, accidents and starvation. 4. Post-release mean dispersion was 377.8 m in the first year and 526.3 m in the second. Mean home range was 7.1 ha in the first year and 5.4 ha in the second. 5. The production systems and handling practices of commercial game farms may have modified some anti-predator ethological patterns and strategies, which might make it more difficult for the birds to adapt and integrate into the wild, resulting in reduced survival due to premature mortality.
On a private property with a stable population of wild Red-Legged partridge (Alectoris rufa) and an appropriate habitat for the survival of the species, reinforcement repopulations were carried out using 54 birds that were 2 to 3 mo old and reared on a commercial game farm. This study aimed to evaluate the effectiveness of repopulations, the behavior in the wild of released partridges, and the possible causes of success or failure of reinforcement population operations. The releases were carried out during August and September of 2 consecutive years. All birds were equipped with radio transmitter collars to determine their behavior after release. Two release methods were used in yr 1: an acclimatization cage (AC) method and a direct release method on the day of the birds arrival (DR). The aim of the release in yr 2 was to collect data to determine the influence of year conditions using the DR method. Of the 54 released birds, none remained alive by the time of the reproductive period in the following spring. The mean survival time was 16.79 d for the AC method and was 11.89 and 5 d for the DR method in yr 1 and 2, respectively. Of the recorded mortalities, we assigned 81.13% to predation, 7.55% to hunting, and 11.32% to unknown causes of death, accidents, or starvation. Repopulation was not successful at providing a long-term increase in partridge numbers, with most birds falling victim to predation within 1 mo of release. Dispersion is the maximum distance from the release point at which each bird was located. The postrelease mean dispersion was 437.65 m for the AC method and was 647.57 and 266.07 m for the DR method in yr 1 and 2, respectively.
We genotyped 24 biallelic sites and 5 microsatellites from the non-recombining portion of the Y chromosome in 652 males from the Canary Islands. The results indicate that, contrary to mtDNA data, paternal lineages of the current population are overwhelmingly (>90%) of European origin, arguing for a highly asymmetric pattern of mating after European occupation. However, the presence of lineages of indisputable African assignation demonstrates that an aboriginal background still persists (<10%). On the basis of distribution and dating of some of these lineages we derived a genetic perspective of settlement processes of the archipelago in two stages, congruent with anthropological, archaeological and linguistic findings.
Injury to a large-caliber artery transurethral resection of a bladder tumor is a rare but serious complication. It is important that an anesthesiologist be able to detect such an injury, in order to include it among the many differential etiological diagnoses for shock. A 75-years-old man reported hematuria. An ultrasound image of the bladder showed many neoformations consistent with a diagnosis of multiple bladder neoplasms, and transurethral endoscopy was performed under subarachnoid anesthesia. Acute hypotension, bradycardia and shock developed 30 minutes into the procedure. The diagnosis was hypovolemic shock due to acute intraoperative hemorrhage, and exploratory laparotomy revealed an opening in the common iliac artery. The rupture was sutured. In spite of administration of crystalloids, colloids, blood products and vasoactive agents, a second operation was required due to hemodynamic instability. The patient died in the intensive care unit.
The Pichia anomala LEU2 gene (PaLEU2) was isolated by complementation of a leu2 Saccharomyces cerevisiae mutant. The cloned gene also allowed growth of a Escherichia coli leuB mutant in leucine-lacking medium, indicating that it encodes a product able to complement the beta-isopropylmalate dehydrogenase deficiency of the mutants. The sequenced DNA fragment contains a complete ORF of 1092 bp, and the deduced polypeptide shares significant homologies with the products of the LEU2 genes from S. cerevisiae (84% identity) and other yeast species. A sequence resembling the GC-rich palindrome motif identified in the 5' region of S. cerevisiae LEU2 gene as the binding site for the transcription activating factor encoded by the LEU3 gene was found at the promoter region. In addition, upstream of the PaLEU2 the 3'-terminal half of a gene of the same orientation, encoding a homologue of the S. cerevisiae NFS1/SPL1 gene that encodes a mitochondrial cysteine desulphurase involved in both tRNA processing and mitochondrial metabolism, was found. The genomic organization of the PaNFS1-PaLEU2 gene pair is similar to that found in several other yeast species, including S. cerevisiae and Candida albicans, except that in some of them the LEU2 gene appears in the reverse orientation.
The Pichia anomala invertase gene (INV1) was introduced at different copy numbers into a sucrose-nonfermenting mutant of Saccharomyces cerevisiae and expressed from its own promoter sequences. The level reached in the production of invertase by the transformants (up to 540 units/10(10) cells) was in agreement with the INV1 gene dosage. Two forms of multimeric active and glycosylated invertase displaying different subcellular locations and molecular masses could be detected in the transformants. One was found to be present in the culture medium and in the periplasm, and the other could only be detected inside the cell. Each of the two heterologous forms of invertase was shown to be an oligomer composed of identical subunits. The difference found in the apparent molecular masses of their monomers (81.5 and 78.3 kDa, respectively) seems to be due to the size of their N-linked oligosaccharide chains (on average 2.4 and 1.9 kDa, respectively), since the number of sugar chains (9) and the molecular mass of the protein moiety (60.5 kDa) are identical in both forms. The shorter size of their oligosaccharides must also be the reason for the lower apparent molecular masses of the heterologous invertases when compared with the enzyme purified from P. anomala. The hypoglycosylated invertase accumulated within the cells of the transformants to an unusual level (up to 130 units/10(10) cells). Such accumulation of active enzyme inside the cells, as well as its underglycosylation, could be due to intrinsic properties of the P. anomala invertase that are determined by the particular primary structure of its protein moiety.
Variation of seven Y-chromosomal DNA polymorphisms, one microsatellite (DYS19), and six biallelic markers (DYS287, DYS271, SRY-2627, SRY-1532, 92R7, and M9), were studied in males from Northwest Africa. To evaluate the degree of differentiation in this region, males from neighboring areas such as the Iberian Peninsula and sub-Saharan Africa were also typed. The results show a large number of paternal lineages of Northwest African origin (over 75%), supporting a long-term population continuity in the area. When the analysis of molecular variance (AMOVA) was performed both on the microsatellite and biallelic marker combinations or haplogroups, a large degree of differentiation among areas was revealed. In spite of these geographic differences, some gene flow between areas was detected by the presence of haplogroups with other geographical origins.
A model for the prediction of eicosapentaenoic acid (EPA) productivity from Phaeodactylum tricornutum cultures that takes into account the existence of photolimitation and photoinhibition of growth under outdoor conditions is presented. The effects of the external irradiance on the culture surface, the average irradiance inside the culture, and the light regime at which the cells are exposed on pigments and EPA content are studied. The chlorophyll content decreases exponentially with the average irradiance, whereas the carotenoids content increases linearly with the external irradiance due to a higher extension of photoinhibition. A decrease in the fatty acid content of the biomass with irradiance on reactor surface is observed when photoinhibition becomes relevant. The average irradiance within the culture mainly influenced the fatty acid profile of the biomass. As the average irradiance becomes higher, percentages of saturated and monounsaturated fatty acids decrease, increasing the portion of EPA. By taking into account the different relationships among pigment and EPA content with the irradiance, the variation in EPA productivity over the year can be simulated as a function of average and external irradiance. For the two photobioreactors employed the maximum EPA productivity is attained in spring and fall (30 mg L(-1) day(-1) for tube diameter 0. 06 m and 50 mg L(-1) day(-1) for tube diameter 0.03 m). In winter, the biomass productivity is limited by low light availability although the EPA content is maximum. In summer, the biomass productivity is higher although the EPA content diminished by photoinhibition; the higher the dilution rate, the lower the minimum. Thus, the conditions that increase the biomass productivity and the polyunsaturated fatty acids content are in opposition, the optimum being reached by operating under photolimitation with high growth rates in order to produce a high proportion of polyunsaturated fatty acids.
The detection and determination of s-triazines, atrazine-desethyl and aziprotryne by cyclic voltammetry and an amperometric method using a metallic copper electrode and a glassy carbon electrode are described. The concentrations of atrazine-desethyl and aziprotryne in 0.1 M NaOH solutions were determined using the oxidation signal corresponding to the Cu(0)/Cu(I) redox process. The detection level calculated for these s-triazines were 0.3 and 0.5 microg/mL of analyte, respectively. The glassy carbon electrode was shown to give sensitive reduction response to aziprotryne in flow injection mode. No special activation was required for the glassy carbon electrode. A detection limit of 0.2 microg/mL (20 ng aziprotryne) was obtained for a sample loop of 0.1 mL at a fixed potential of -1.0 V (vs. Ag/AgCl) in 0.1 M HCl and a flow rate of 3.5 mL/min. Furthermore, the glassy carbon electrode showed stable response in such a system, and the relative standard deviation was only 2.7% using the same surface, and 6.3% using different surfaces. The method developed was applied to the determination of aziprotryne in environmental and tap water samples; using a prior solid-phase extraction step, aziprotryne concentrations lower than 1.0 ng/mL could be measured.
Inhaled acetaldehyde may induce bronchoconstriction in asthmatic subjects and provides a new method to investigate airway responsiveness. The objective of the study was to determine whether acetaldehyde was a more specific stimulus than methacholine in differentiating asthma from chronic bronchitis with or without airflow limitation. Bronchial provocation challenges with methacholine and acetaldehyde were performed in 62 asthmatics and in 59 smokers with chronic bronchitis (32 with chronic bronchitis alone and 27 with chronic bronchitis and coexisting chronic obstructive pulmonary disease (COPD)). The response to both bronchoconstrictor agents was measured by the provocative concentration required to produce a 20% fall in forced expiratory volume in one second (FEV1; PC20). The two types of challenge yielded a similarly high level of sensitivity (100% for methacholine and 92% for acetaldehyde) in revealing airway hyperresponsiveness in asthma. However, bronchoprovocation with acetaldehyde yielded considerably greater specificity (95%) than bronchoprovocation with methacholine (24%) in separating asthma from chronic bronchitis. In subjects with asthma, methacholine and acetaldehyde responsiveness were weakly but significantly correlated (r=0.42, p=0.001) but no correlation was found between airway responsiveness to acetaldehyde and baseline FEV1 (r=0.13, p=0.33). These findings suggest that the demonstration of bronchoconstriction in response to acetaldehyde may be a more specific test than methacholine in the differentiation of asthma from chronic bronchitis. Furthermore, methacholine and acetaldehyde hyperresponsiveness are not reflecting the same pathophysiological process in the airways.
In this paper, we report a method for isolation of high molecular weight DNA from Leishmania promastigotes. This technique is especially indicated for small-scale purification of DNA suitable for the construction of highly representative genomic libraries. In our protocol, lysis buffer is compatible with RNase treatment, avoiding an additional precipitation step and consequent shearing of DNA. In order to prove the quality of the DNA isolated by this method, a Leishmania braziliensis genomic library was constructed, and an L. braziliensis KMP-11 gene was cloned after screening the library with a heterologous probe.
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BACKGROUND: Psychotic symptoms appear during the course of Alzheimer's disease, but their frequency and intensity vary according to different studies and their nature remains unsettled. OBJECTIVES: To study the frequency and intensity of psychotic symptoms in two transversal series of patients with Alzheimer's disease and analyze its relationship with the duration of the disease and severity of cognitive impairment. PATIENTS AND METHODS: This study has been carried out in patients suffering from probable Alzheimer's disease (NINDS-ADRDA criteria). The stage of the disease was determined according to FAST, and the intensity of cognitive impairment in Mini Mental State Examination was classified as mild, moderate or severe. Frequency and intensity of psychotic symptoms (delusions, hallucinations and misidentifications) were determined by means of semistructured interviews (BEHAVE-AD 78 patients and CUSPAD 69 patients). The results obtained in these three groups of patients were compared through ANOVA variance analysis and mean contrast. Variance and covariance analysis were done to determine the relationship between psychotic symptoms and other variables (degree of cognitive impairment, length of evolution and stage of the disease). For this purpose, the patients with Alzheimer's disease but without psychotic symptoms were considered as control and compared to patients with psychotic symptoms. RESULTS: Nearly half the patients had psychotic symptoms. Delusions appeared earlier and were more frequent than hallucinations and misinterpretations. The more severe was the cognitive impairment, the more frequent and intense were psychotic symptoms, but the difference was significant only in cases with severe cognitive impairment. Hallucinations appeared mainly in patients with advanced dementia and were related firstly with the intensity of functional and cognitive impairment and secondly with the duration of the disease. CONCLUSIONS: Mild psychotic symptoms, especially delusions, appear early during the course of Alzheimer's disease. The frequency and intensity of these symptoms increase in parallel with the functional and cognitive impairments caused by the disease. Hallucinations, which appear mainly when the dementia is severe, can be considered as an evolutive marker of the process. Psychotic symptoms differ from those occurring in other disorders, either neurologic or psychiatric in nature.
Thyroid lymphoma represents less than 1% of malignant thyroid tumors and its diagnosis is difficult. We report a 25 years old woman, admitted with the diagnosis of diffuse euthyroid goiter and thyroid cancer. She was subjected to a subtotal thyroidectomy and the pathological study of the surgical piece showed a Hodgkin lymphoma, subtype nodular sclerosis. The patient was treated with three cycles of chemotherapy, using cyclophosphamide, vincristine, procarbazine, prednisone, doxorubicin, blemycin, vinblastin and radiotherapy. She refused to continue treatment after the third cycle and after 3 years and 5 months of follow up, is well and free of disease.
This report explains a rapid procedure (approximately 50 min) for the isolation of highly purified total RNA from Leishmania promastigotes based on extraction with acidic phenol. The simplicity of the manipulations required make this method ideal for processing multiple samples; the quality of the RNA obtained is suitable for reverse transcription polymerase chain reaction analysis.
A new continuous epitope of hepatitis A virus (HAV) was defined in the VP3 protein. Convalescent sera recognised the synthetic peptide 3110-3121 (FWRGDLVFDFQV). The replacement of the arginine, glycine, or aspartic acid at positions 112, 113, or 114, respectively by other amino acids induced the loss of synthetic peptide recognition by human convalescent sera, thereby confirming the presence of an epitope in the original VP3(110-121) sequence. Shorter VP3 peptides such as VP3(110-119). VP3(110-117), and VP3(110-116) and a tandem repeat of VP3(111-116) failed to react with convalescent sera, indicating the importance of the entire peptide in the epitope structure. The maximum inhibition of human convalescent binding to HAV by the VP3(110-121) peptide was around 60%, and 50% inhibition was achieved at a peptide concentration of 2.3-2.4 micrograms/ml. Antibodies generated by this peptide bound to intact HAV and neutralised its infectivity. Antipeptide antibodies inhibited convalescent serum binding to HAV. Monoclonal antibodies H7C27 and MAK-4E7 inhibited completely binding of the antipeptide antibodies to HAV.