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Biomedical subjects

R Santos

Publications and source records attributed to R Santos.

At least 19 recordsLinked to original sources
PubMed1998

Modification of Saccharomyces cerevisiae thermotolerance following rapid exposure to acid stress.

Thermotolerance was induced in cells of Saccharomyces cerevisiae YPH499 pre-exposed, during 10 min and in the presence of glucose, to a mild acid-stress with HCl at pH 3.5. Thermotolerance was not induced in cells exposed to a severe acid stress by 50 mM acetic acid at pH 3.5, or HCl at pH 2.5 or pH 2.0. Yeast cells pre-incubated under glucose starvation were found to be more tolerant to a lethal heat stress than cells pre-incubated in glucose-supplemented media, despite the pH value of the media (range 2.0-6.5) and the type of acidulant used (HCl or acetic acid). Moreover, the high thermotolerance exhibited by cells pre-incubated at pH 6.5 for 10 min under glucose starvation was not significantly modified by the acidification of the pre-incubation medium. Results are discussed based on the effect that glucose and a mild or severe acid stress have on plasma membrane H+-ATPase activity and on cytosolic pH values, estimated in a previous work.

Acetic Acid↗
PubMed1998

Principles for Sustainable Governance of the Oceans

Pressures being exerted on the ocean ecosystems through overfishing, pollution, and environmental and climate change are increasing. Six core principles are proposed to guide governance and use of ocean resources and to promote sustainability. Examples of governance structures that embody these principles are given.

Journal Article↗
PubMed1998

Genome diversity in temperate bacteriophages of Oenococcus oeni.

The genome structure of six bacteriophages of Oenococcus oeni was compared. Two distinct groups with no apparent restriction site conservation were defined. In members of the alpha group (fOgML34, fOg4029, fOg30 and fOg218) a 7.5 kb region containing the origin of DNA packaging (cos) was highly conserved. Stretches of DNA heterogeneity could also be assigned to particular regions and were mostly evident in the right area of the genomes. fOg44 and fOgPSU1 (beta group) were indistinguishable in the left half of their genomes, including cos, but were markedly dissimilar in other regions. Strong labelling signals detected in cross-hybridizations involving members of different groups were confined to fragments centrally located in their physical maps. The attachment site (attP) of fOg44 was assigned to this conserved region. It is suggested that recombination events at this location may have been important in generating the observed diversity of oenophage genomes.

Bacteriophages↗
PubMed1998

[Current concepts in maxillo-facial surgery].

The authors make a brief and concise overview of the evolution of maxillofacial surgery over the last decades namely the concepts and methods used. Some case reports are presented which illustrate the application of the current methodology with the purpose of covering various fields of application (traumatologic, othognatic and tumoural). The need for an interdisciplinary assessment of these patients is discussed.

Adolescent↗
PubMed1997

Severe latex allergy after a vaginal examination during labor: a case report.

There has been an alarming increase in latex allergy, which can be a potential cause of occupational atopic disease. Physicians should be aware of this entity in high-risk groups and in patients with other allergies. A 32-year-old pregnant woman, with an allergy to orange juice, was first seen with a 39-week pregnancy in the labor room, where she had on two occasions a severe atopic reaction when examined with a latex glove. A latex allergy was suspected, and management with hydrocortisone resulted in remission of symptoms. Two hours later a vaginal delivery was performed with nonlatex, nonvinyl gloves. A week later immunoglobulin E antilatex antibodies determined by radioallergosorbent test were still positive at 585 IU. It is concluded that symptoms of latex allergy may develop in high-risk groups or in those with other known allergies. Because of the increasing frequency of this entity, physicians should take greater care and give more attention to the clinical history, as well as be aware of this possibility in these groups of patients.

Adult↗
PubMed1997

Mechanisms underlying degeneration of cryopreserved vascular homografts.

OBJECTIVE: To analyze the mechanism(s) underlying homograft degeneration, we designed an experimental model in which the behavior of cryopreserved autografts and homografts, as well as fresh autografts, implanted in the same animal was compared. METHODS: A cryopreserved homograft was implanted in the aorta of 14 sheep. The excised aortic autologous segment was then subjected to cryopreservation, and 1 to 8 weeks later it was implanted 1 to 2 cm below the cryopreserved homograft. The intermediate segment of the native aorta, the fresh autograft, was dissected at this point. Animals were put to death at different times and the implanted segments were harvested together with a portion of native aorta. Histologic and immunohistochemical analyses, as well as cell viability assessments, were then performed on the explanted segments. Similar studies were also conducted on fragments of cryopreserved autografts and homografts before implantation. RESULTS: With the exception of a partial loss of the endothelium, cryopreserved specimens retained cell viability and morphologic integrity before implantation. Explanted cryopreserved homografts showed profound changes affecting all strata, as well as a decline in cell viability. Lymphocyte infiltrates were found up to 12 months after implantation. Endothelium was always absent in cryopreserved homografts. However, a reendothelialization of the cryopreserved autografts was observed. After an initial period of neuronal degeneration, reenervation of the cryopreserved autograft segment occurred 6 to 12 months after the operation. Findings regarding the fresh autografts were similar to those of the cryopreserved autografts. CONCLUSION: Our results suggest that the immunologic reaction rather than the cryopreservation process is responsible for the degenerative process occurring in cryopreserved homografts.

Animals↗
PubMed1997

Anatomical and echocardiographic correlates of normal cardiac morphology in the late first trimester fetus.

OBJECTIVES: To describe the normal cardiac morphology as seen by transvaginal ultrasound imaging in the first trimester fetus and to compare it with the morphology of the heart as seen by microdissection at the same gestational age. DESIGN: In 53 mothers undergoing early sonography, the fetal heart was examined and the images recorded. The gestational age range was 5-12 weeks of gestation, which represents 21 to 70 days after conception. Images were analysed frame by frame and compared with the anatomy of embryos and fetuses at the same gestational ages. RESULTS: After the 9th week of gestation, four cardiac chambers, the aortic origin, and the pulmonary artery could be identified on cross sectional echocardiography in conjunction with colour flow Doppler. At 9 weeks, the apex pointed anteriorly and the right ventricle and pulmonary artery lay to the right of the midline. By the 11th week of gestation, the apex pointed to the left and the pulmonary artery lay to the left of the midline as in the older fetus. Between 9 and 12 weeks' gestation the aorta was larger than the pulmonary artery. These findings were confirmed in the microdissected hearts. CONCLUSIONS: The current quality of ultrasound images obtained using transvaginal transducers in the first trimester fetus allows the study of fetal cardiac anatomy. Some of the later developmental changes can be demonstrated. As technology improves further the details of earlier cardiac morphogenesis may also become visible.

Dissection↗
PubMed1997

[Severe syndrome of ovarian hyperstimulation. Incidence, value of criteria of risk factors and preventive methods].

Statistical analysis; square Chi test, Pearson, were practiced, from 1994 to 1996. There were 368 hyperstimulated cycles; three SHOS cases without risk factors and 28 cases with risk factors without SHOS. Risk factors presented were: average seric estradiol 6643.59 +/- 2320 pg/ ml; average follicles: 26.6 +/- 6.9; ovules recuperated by aspiration: 19.32 +/- 9.1. There were five groups according to preventive methods: albumin (13 patients, coasting (one patient); albumin-coasting (11 pacientes); albumin-embryo freezing (3 patients); embryo freezing (one patient). None of the patients presented SHOS.

Analysis of Variance↗
PubMed1996

Age and the ovarian follicle pool assessed with transvaginal ultrasonography.

OBJECTIVE: We tested whether transvaginal ultrasonography could detect the age-related decrease in follicle counts that has been observed in autopsy studies. STUDY DESIGN: Thirty-one healthy volunteers in three age groups (22 to 25, 30 to 33, and 39 to 42 years) underwent ultrasonography in the follicular and luteal phases of the menstrual cycle. At the conclusion of the study the 124 ovarian scans were randomly ordered and antral follicles > or = 2 mm were counted by an evaluator unaware of age. Ordinary least-squares linear regression was used to estimate the associations of age with the total antral follicle count and with ln (1 + follicle count). RESULTS: The numbers of antral follicles > or = 2 mm decreased by about 60% between 22 and 42 years. Age-related decreases were similar for both phases of the cycle and held for both smaller (2 to 3.5 mm) and larger (>3.5 mm) follicles. CONCLUSION: We hypothesize that ultrasonographically derived counts of follicles provide a measure of reproductive age that may help to predict age-related phenomena.

Adult↗
PubMed1996

Autosomal dominant cataracts of the fetus: early detection by transvaginal ultrasound.

Cataracts are lens opacities that account for approximately 10% of blindness in children. We report on four consecutive pregnancies in a woman at risk for recurrent autosomal dominant cataracts in which extensive ultrasound studies were helpful in establishing the correct diagnosis. The normal appearance of the fetal lens is that of a ring with a central sonolucency, but in cases of cataracts the lens appears hyperechogenic to various degrees. In the first pregnancy, normal lenses were seen at 15 postmenstrual weeks and, at birth, the baby girl had normal lenses. In the second pregnancy, the male fetus was affected by a left-sided cataract and a right-sided anophthalmia which were diagnosed at 16 postmenstrual weeks. The histological examination of the specimen from the aborted fetus correlated with the sonographic diagnosis. The third pregnancy, also a male fetus, had bilateral cataracts suspected at 14 weeks, but the final diagnosis was made at 19 weeks and confirmed at 21 weeks. The couple opted to terminate the pregnancy and the histology confirmed the presence of congenital cataracts. In the fourth pregnancy, we diagnosed asymmetry of the orbital sizes and bilateral cataracts at 15 weeks. In conclusion, the diagnosis of fetal cataract from the second trimester of pregnancy is possible and imaging of the fetal lenses should be part of the routine anatomical survey. Since the exact onset of fetal cataracts is uncertain at present, in cases at risk, serial sonograms may be indicated.

Adult↗
PubMed1996

Carcinoid tumor and the nephrotic syndrome: a novel association between neoplasia and glomerular disease.

Various malignancies are associated with the paraneoplastic evolution of the nephrotic syndrome. Renal biopsy in these instances frequently shows membranous glomerulonephritis. We describe a patient who had metastatic bronchial carcinoid tumor with development of microscopic hematuria and subsequent nephrotic syndrome in conjunction with another paraneoplastic process, a malignancy-related neuropathy. A decline in actual glomerular filtration rate led to percutaneous renal biopsy, which revealed fine holes in the glomerular basement membrane and focal capillary corrugation. Electron microscopy showed numerous small subepithelial dense deposits and fusion of foot processes, confirming the diagnosis of stage I membranous nephropathy. We believe this is the first published case of true carcinoid tumor associated with the nephrotic syndrome and a specific paraneoplastic glomerular lesion. Carcinoid tumor should be considered in the spectrum of malignancies associated with paraneoplastic development of the nephrotic syndrome.

Basement Membrane↗
PubMed1996

Delay in progression of bone metastases in breast cancer patients treated with intravenous pamidronate: results from a multinational randomized controlled trial. The Aredia Multinational Cooperative Group.

PURPOSE: Bone metastases are a major cause of morbidity in breast cancer, resulting in complications that include pain, loss of mobility, pathologic fracture, and tumor-induced hypercalcemia (TIH). Inhibition of osteoclast-mediated bone destruction using bisphosphonates represents a promising new management approach. PATIENTS AND METHODS: Breast cancer patients with bone metastases were randomly allocated to receive chemotherapy alone (152 patients) or chemotherapy plus pamidronate 45 mg in 250 mL of saline as a 1-hour intravenous infusion every 3 weeks (143 patients). Whenever possible, treatment continued until progression of disease (PD) in bone appeared on radiographs or bone scan. Time to PD in bone and pain reduction according to a self-assessment six-point scale were selected as primary end points. PD in bone was verified during extramural review (EMR) of all imaging studies by blinded observers, and these data were used as the main efficacy criterion. Analgesic intake, World Health Organization (WHO) performance status, and complications of bone metastases (radiotherapy, TIH, fractures, orthopedic surgery) were also compared in the two groups. RESULTS AND CONCLUSION: At EMR, median time to PD in bone was increased by 48% in patients who received pamidronate (249 v 168 days; P = .02, Wilcoxon test). Marked pain relief, defined as a two-point decrease lasting for > or = 6 weeks, was reported by 44% of pamidronate patients and by 30% of controls (P = .025, chi 2 test). The infusions (median, nine per patient; range, 0 to 39) were well tolerated, with no major toxicities reported. Pamidronate by repeated infusion can significantly slow the progression of bone metastases and reduce attendant morbidity.

Adult↗
PubMed1996

[Hyponatremia as a complication of laparoscopic hysterectomy. Report of a case].

The case of a 42 years old woman, who had laparoscopic hysterectomy and seven hours after presented with a convulsive crisis and later a coma status, secondary to hyponatremia. Hyponatremia causes, are discussed, as well as its relationship with syndrome of inadequate secretion of antidiuretic hormone, diagnosis, management, prognosis factors and risk.

Adult↗
PubMed1995

Histologic and genetic assessment of explanted allograft valves.

A possible way of analyzing the immune response triggered by the allograft and the cellular viability is to compare immunocompetent and immunosuppressed patients, such as those having valve replacement and heart transplantation, respectively. These groups differ in immunosuppression therapy, preparation methods, valve hemodynamics. In the present study, we investigated polymerase chain reaction-amplified DNA flanking hypervariable (CA)n regions obtained from valve leaflets taken from patients having valve replacement or heart transplantation and performed a histologic analyses of the cells. In addition, we assessed an autograft valve to compare the hemodynamic effects on the cellular composition of the valve leaflet. We conclude that leaflet cellularity of the heart transplantation and autograft patients is superior to that of the valve replacement patients. These differences were consistent with the occurrence of an immune response in the valve replacement group, which was prevented or abrogated by immunosuppressive therapy administered to the heart transplantation group. However, it cannot be excluded that preparation procedures have a long-term effect on the extracellular matrix, leading to deterioration of cell adhesion and homing conditions.

Adult↗
PubMed1995

Amantadine stimulates sexual behavior in male rats.

The effects of amantadine on sexual behavior, penile erection, and seminal emission of male rats was studied. Amantadine significantly decreased latency of mounts in all doses (1.25 to 50 mg/kg), and decreased the number of mounts and intromission latency at the highest doses used. The lowest dose of amantadine significantly increased ejaculation latency and intromission frequency, while higher doses significantly reduced it, which indicates a biphasic response of the drug. Additionally, seminal emission, erections, and genital grooming were significantly induced by amantadine. Amantadine-induced seminal emissions were impaired by spinal cord transection, which suggests the involvement of supraspinal structures in the drug action. Haloperidol and atropine sulphate significantly reduced seminal emissions and penile erections induced by amantadine. These results demonstrate that amantadine stimulates sexual behavior and genital reflexes in male rats and suggest a facilitatory effect of the drug that probably involves different mechanisms of action.

Amantadine↗
PubMed1995

The allograft valve in heart transplantation and valve replacement. Genetic assessment of the origin of the cells by means of deoxyribonucleic acid profiles.

Assessment of the cellular origin of allograft valves is essential in comprehending their biologic behavior and in improving preparation methods. In this study we retrospectively analyzed 10 allografts obtained from patients who underwent valve replacement or heart transplantation. Histologic evaluation and deoxyribonucleic acid amplification by polymerase chain reaction technology with fluorescence labeled primers was performed on different parts of the valve leaflets. Automated analyses of the obtained amplimers showed in the heart transplantation group the presence of receptor cells interspersed with native donor cells in three cases. Preliminary results for the valve replacement group are inconclusive as yet.

Adult↗