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Biomedical subjects

R Santos

Publications and source records attributed to R Santos.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1994

Preparative isolation of the lectin jacalin by anion-exchange high-performance liquid chromatography.

The lectin jacalin from Artocarpus integrifolia was purified to homogeneity in a single step by preparative anion-exchange high-performance liquid chromatography (HPLC). Selection of the optimum chromatographic parameters in gradient elution allowed a rapid procedure to be obtained for the qualitative and quantitative isolation of the most important alpha- and alpha'-jacalin components. A recovery of 27-33% was obtained from a total soluble extract using a polyacrylate-DEAE HPLC column. The identities of the two isolated polypeptides were established by N-terminal amino acid sequence analysis and from the IgA1 binding lectin activity.

Amino Acid Sequence↗
PubMed1994

Amniotic sac, fetal heart area, fetal curvature, and other morphometrics using first trimester vaginal ultrasonography and color Doppler imaging.

Ultrasonographic morphometric measurements were obtained with transvaginal ultrasonography from 121 patients with first trimester singleton pregnancies. Amniotic and gestational sac diameters, fetal heart area, and fetal length increased in a linear rate relative to crown-rump length, whereas the amniotic and gestational sac volumes increased at an exponential rate. The yolk sac exhibited a biphasic growth pattern with a peak at a crown-rump length of 3.5 cm. The ratio of crown-rump length to anteroposterior dimension increased over the first trimester, suggesting less curvature in older fetuses. In conclusion, vaginal ultrasonography permits accurate measurement of many new morphometric parameters.

Amnion↗
PubMed1994

Comparison of the selective aromatase inhibitor formestane with tamoxifen as first-line hormonal therapy in postmenopausal women with advanced breast cancer.

A total of 409 postmenopausal patients with advanced metastatic breast cancer were randomized to receive either formestane (Lentaron) 250 mg every 2 weeks by intramuscular injection, or tamoxifen 30 mg/day orally. Treatment continued until tumor progression. The groups were well matched for pretreatment characteristics including age, performance status, hormone receptor status (patients with known negative receptor status of their primary tumor were excluded), site and extent of metastases, disease-free interval, and previous primary and adjuvant therapy. Patients were assessed for antitumor efficacy at 3-monthly intervals using UICC criteria. Of the 348 patients evaluable for response, 33% had an objective response to formestane (14 complete and 43 partial responses), while 37% had an objective response to tamoxifen (10 complete and 54 partial responses). Median duration of response was 15 months for formestane and 20 months for tamoxifen; survival was 35 and 38 months respectively. There were no statistically significant differences between the treatments for all these variables, but time to disease progression and time to treatment failure significantly favoured tamoxifen. Systemic tolerability was excellent for both treatments. Local side effects due to intramuscular injection of formestane were mild and transient. In this comparative trial of first-line therapy for advanced breast cancer, formestane gave results comparable to tamoxifen for both efficacy and tolerability. We conclude that formestane is an effective and well tolerated addition to the therapeutic options available for the treatment of postmenopausal women with advanced breast cancer.

Adult↗
PubMed1994

[Laparoscopic hysterectomy. Initial experience].

The results of the first twelve cases of Laparoscopic Assisted Vaginal Hysterectomy, are presented. The indications for hysterectomy were myomatosis, suspicion of adenomyosis and endometriosis. The surgical technique is described in detail in which a combination of bipolar Kleppinger forceps and reusable scissors were employed. There were two intraoperative accidents. One subcutaneous emphysema of the left half of the abdominal wall, thorax, neck, face and upper limb. The second case was a damage to a branch of the left epigastric artery. The average time was 4 hours 31 minutes which includes 9 patients to which another surgical procedure was practiced. There was no significant bleeding in any of the patients. The postoperative complications were 1 hyponatremia that needed the use of an Intensive Care Unit and the other was periumbilical hematoma of 3 cm. of diameter. The patient was discharged on the one to three postoperative day with an average of two days. The average hospital fee was 35% higher than an abdominal hysterectomy. All the surgery were videotaped and later viewed by the patients. It was concluded that the laparoscopic assistance that is offered to the vaginal hysterectomy is particularly advantageous for hysterectomy especially in the cases where absence of genital prolapse, when uni or bilateral Adnexectomy is required, previous past history of abdomino-pelvic surgery, endometriosis and adhesions. This procedure should be included in the armamentarium of the Gynecological Surgeons but only after and appropriate training.

Adenoma↗