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Biomedical subjects

A Alvarado

Publications and source records attributed to A Alvarado.

At least 19 recordsLinked to original sources
PubMed1992

Disruption of endothelial barrier function by lipolytic remnants of triglyceride-rich lipoproteins.

Remnants, resulting from the lipolysis of triglyceride-rich lipoproteins, injured cultured endothelial cells and resulted in decreased barrier function of the vascular endothelium. Endothelial cells were cultured on micropore filters. Albumin transfer across endothelial cell monolayers was measured after a 24-h exposure to media enriched with control or in vitro-lipolyzed samples of various hypertriglyceridemic (HTG) sera and its isolated lipoprotein (VLDL, LDL and HDL) and serum free protein (d greater than 1.21 g/ml) fractions. Compared with control cultures, neither control HTG serum nor its isolated lipoprotein and serum-free protein fractions had any effect on albumin transfer. In contrast, lipolyzed HTG (L-HTG) serum and all of its isolated lipoprotein fractions (L-VLDL, L-IDL, L-LDL and L-HDL) caused a marked decrease in endothelial barrier function, evidenced by a significant increase in albumin transfer across endothelial monolayers. The L-IDL and L-HDL fractions were more effective in increasing albumin transfer than the L-VLDL and L-LDL fractions. The extent of the L-IDL and L-HDL mediated increases in albumin transfer was concentration dependent. An exposure of 12 h was required for L-HDL to increase albumin transfer. The L-HDL mediated increase in albumin transfer was reversible only after a 12-h exposure at low concentrations. The free protein fraction from L-HTG serum had no significant effect on the barrier function of endothelial cells. The presence of normolipidemic HDL in culture medium prevented disruption of the endothelial barrier induced by L-IDL but not by L-HDL. The decrease in endothelial barrier function induced by lipolyzed samples of HTG serum or lipoproteins appeared to be correlated with the level of free fatty acids contained in lipolytic remnants. Enrichment of LDL, and in particular HDL, with fatty acid significantly increased albumin transfer. Compared with lipolyzed samples, sera/lipoproteins oxidized in vitro by Cu2+ ions had little effect on endothelial barrier function, which did not correlate with their respective thiobarbituric acid-reacting substance (TBARS) values. TBARS remained within normal range after L-HDL incubation with endothelial cells for up to 48 h. At most concentrations tested, exposure to lipolyzed but not oxidized lipoproteins resulted in morphological perturbations of cell monolayers. These data suggest that lipolytic remnants of triglyceride-rich lipoproteins may play an important role in the development of atherosclerosis by decreasing the barrier function of the vascular endothelium. The remnant-induced injury of the arterial wall may permit the entry of cholesterol-rich lipolytic remnants as well as LDL into the arterial wall.

Animals↗
PubMed1992

[Incidence and surgical treatment of extrahepatic abdominal hydatidosis].

From 1974 to May 1991, 417 patients with abdominal hydatid cyst disease were surgically treated. Twenty-eight patients had extrahepatic abdominal cyst disease (6.7%). Six patients had only extrahepatic disease where as 22 had associated hepatic and extrahepatic cysts. Most frequent sites were the peritoneum (52.7%), the spleen (22%) and pelvis (11%). Fourteen out of the 14 CT scans performed, detected the extrahepatic cysts. The preferred surgical technique was total closed cystectomy (in hepatic and extrahepatic cysts). Resection of the organ affected (8 splenectomies, 1 nephrectomy, 1 partial vertebral resection, 1 orchiectomy and 1 salpingo-oophorectomy) was also performed. There was no mortality and morbidity was 32.1%: 3 intraabdominal abscesses, 1 intraabdominal haemorrhage, 4 biliary fistulae and 1 partial necrosis of the large bowel. Only 3 patients (neither were treated with mebendazole) were reoperated on for recurrent peritoneal hydatic cyst.

Abdomen↗
PubMed1992

[Urethral lengthening with a tube flap (Kropp's operation) and gastrocystoplasty].

Gastrocystoplasty associated to a Kropp procedure in our experience has been an excellent alternative to improve the quality of life and renal function in patients with severe bladder dysfunction and urinary incontinence. Technically offers easy development of a gastrointestinal segment not requiring ureteral reimplantation or detubularization with the consequent excess of sutures required traditionally in these procedures. Also the postoperative care was smoother and shorter than previously using with the obvious advantage of less mucus production and no metabolic disturbances often present. Further catheterization might be performed through a physiological way obviating abdominal stomas.

Adolescent↗
PubMed1991

Detection of antibodies to mycoplasmas in South American camelids.

Indirect haemagglutination tests on sera from 757 South American camelids (alpacas, llamas and vicunas) carried out in the Andean region of Peru, revealed evidence of exposure mainly to Mycoplasma mycoides subspecies mycoides LC. The incidence of detectable antibodies to this mycoplasma in 554 alpacas was 5.0 per cent and in 141 llamas 15.6 per cent. Antibody to Mycoplasma capricolum and the F38 biotype was detected in 0.9 per cent and 0.2 per cent of alpacas, respectively. In a group of 62 vicunas only one reactor to both M m mycoides LC and M capricolum was observed. No reactors to M mycoides subspecies capri or M agalactiae were observed in the flocks examined. Antibodies to mycoplasma were also detected in nine out of 10 goat flocks tested. The incidence of antibodies to M m mycoides LC was 13.8 per cent, 3.8 per cent for M capricolum and 1.8 per cent for the F38 biotype. In a group of 110 sheep, six reactors (5.5 per cent) to M m mycoides LC and one (0.9 per cent) to F38 were observed. The implications of these results are discussed in relation to the involvement of mycoplasmas in existing disease in camelids in Peru.

Animals↗
PubMed1991

[Ureteroscopy. Experience and results].

Ureteroscopy is an Endo-urological procedure which has been practiced around the world in all teaching centers of Urology. It presents obvious advantages. Our experience has been satisfactory, not only due to the coordinated and joint work, but for the results obtained in behalf of our patients who went back to their regular activities shortly after. As all the new procedures, it has a learning curve which is given after the initial training has been acquired but its performance will give expertise, same as radiologic technology and the development of new instruments with smaller diameter and accessories which allow the easier access to ureter and lithotripsy.

Adolescent↗
PubMed1991

[Multifactorial analysis of patients with endometriosis in an institutional program of assisted reproduction].

It is a retrospective and transverse study with an analysis of results from patients submitted to intrauterine insemination (IIU), intratubal gamete transfer (GIFT) and in vitro fertilization and embryo transfer (FIVTE), at the Clinic of Assisted Reproduction, Instituto Nacional de Perinatología in Mexico City. From 134 cycles of patients submitted to IIU, 113 corresponded to women with diagnosis of sterility from non determined cause, and 21 to cases with endometriosis, and at least one permeable tube. From the first group, 22 pregnancies were obtained, for a monthly fertility rate of 19.4%; and from the second one, 12 pregnancies with a fertility rate of 56%. This, which is very high , may be explained by the relatively small number of cases in the second group, or else, by the influence of a previous medical treatment for endometriosis; the square Chi analysis shows a P less than 0.01 in the two groups. In the GIFT and FIVTE cases, from which 35 cycles were analyzed, per each procedure, there were 10 pregnancies, 9 for GIFT and one for FIVTE; the amount is very limited in order to obtain conclusions, but it seems that there is a proportional tendency in GIFT to less amount of pregnancies in women with endometriosis. The analysis of hormonal follow up did not show differences in the groups, and the averages may be useful to determine, early, the cancellation, or not, of an stimulation cycle. Finally, in FIVTE cases there is a diminution of fertilization index in women with endometriosis (53%), as compared with the cases without disease (80%).(ABSTRACT TRUNCATED AT 250 WORDS)

Cross-Sectional Studies↗
PubMed1990

Lack of association between thyroid function and mitral valve prolapse in Graves' disease.

1. To determine whether the association between mitral valve prolapse and Graves' disease is related to thyroid function, three groups of individuals were studied: 16 patients with Graves' disease and hyperthyroidism (hyperthyroid: T4 greater than 11.5 micrograms/100 ml), 16 patients with Graves' disease without hyperthyroidism (euthyroid: T4 less than 11.5 micrograms/100 ml), and 40 healthy individuals. The three groups were similar in age, sex distribution, and anthropometrical characteristics. 2. All patients were evaluated clinically and by M-mode and two-dimensional echocardiography to determine the presence of mitral valve prolapse. 3. The frequency of mitral valve prolapse was similar in the hyperthyroid (31%) and euthyroid patients (25%), but was higher than in the normal individuals (5%). The frequency of systolic murmur was higher in the hyperthyroid patients (75%) than the euthyroid patients (19%) or the normal subjects (0%); however, the presence of a murmur was not associated with mitral valve prolapse. Hyperthyroid (13%) and euthyroid (13%) patients had a higher frequency of clicks than the normal individuals (0%), and the presence of click was associated with mitral valve prolapse. 4. Although patients with Graves' disease have a higher frequency of mitral valve prolapse, this is not associated with thyroid function. The presence of a click but not the presence of a systolic murmur may be a clinical indicator of mitral valve prolapse in Graves' disease.

Adult↗
PubMed1989

Clinical evaluation of the Capronor contraceptive implant: preliminary report.

Capronor, a single-capsule, biodegradable, subdermal contraceptive that releases levonorgestrel over a 12- to 18-month period, has been evaluated in 48 healthy women, ages 18 to 40 years. Sixteen participants received a 2.5 cm capsule (12 mg of levonorgestrel), and 32 received a 4.0 cm capsule (21.6 mg of levonorgestrel). Serum levonorgestrel levels were significantly lower in the 2.5 cm group. Ovulation occurred in all cycles in the 2.5 cm group and in 26.3% of cycles in the 4.0 cm group. Levonorgestrel levels with the shorter capsule were too low for reliable contraception in all users, and 4 cm may be a minimal functional length. Bleeding patterns were regular in most women who ovulated and irregular in most remaining subjects. It is assumed that changes in cervical mucus and the endometrium contributed to effective contraception despite the frequency of ovulation.

Administration, Cutaneous↗
PubMed1988

Tryptophan 2,3-dioxygenase in chick embryo hepatocytes: studies in ovo and in culture.

Tryptophan dioxygenase is a hemoprotein in its active form, which has a relatively low affinity for heme. From previous studies in rats, the ratio of holoenzyme/total enzyme activity of tryptophan dioxygenase has been proposed to reflect the size of a "free" heme pool in hepatocytes. Chick embryo hepatocytes in ovo and in culture are other systems that have proven useful for study of hepatic heme metabolism and its control. Heretofore, there have been few studies of tryptophan dioxygenase activity in chick embryo hepatocytes. As part of studies on hepatic heme metabolism, using two different assays, we have measured tryptophan dioxygenase activity and percentage of heme saturation of the enzyme in chick embryo livers cells in ovo and in culture. One method of assay relies on endogenous formamidase to generate the final product, kynurenine, which is measured directly, whereas the other method uses a chemical hydrolysis step to form kynurenine which is further diazotized prior to measurement. The latter method is shown to be preferable for studies with chick embryo hepatocytes. In addition, we show that (i) tryptophan dioxygenase activity is present and can be increased by tryptophan and phenobarbital-like drugs in chick embryo hepatocytes in ovo; (ii) total enzyme activity falls markedly in cultured hepatocytes despite the presence of high concentrations of glucocorticoids in the culture medium; and (iii) under all conditions studied thus far in the cultures, the enzyme is nearly saturated with heme. Results are discussed in relation to regulation of heme metabolism in chick embryo hepatocytes.

Animals↗
PubMed1987

Cellular immunity and IgE levels in atopic patients.

Twenty young adult atopic patients and their matched controls were studied. Spontaneously generated and Con-A-induced suppressor T cell functions as well as Natural Killer (NK) activity against K-562 target cells, measured in a short-time 3H-thymidine uptake, were evaluated. Suppressor T cell activity in the patients was more than 2 SD lower than that found in the controls and there was, contrary to expectation, a direct correlation between suppressor function and serum IgE levels. Atopic patients showed a statistically significant lower NK activity than normal controls when related to a low IL-2 production. Both facts inversely correlated with the concentration of IgE in serum. We concluded that atopic patients' vulnerability to viral infections may be due to defective NK activity. Suppressor T cell function is abnormal in these patients. Both defects could be due to a faulty immunoregulatory helper function.

Adolescent↗
PubMed1986

A practical score for the early diagnosis of acute appendicitis.

We conducted a retrospective study of 305 patients hospitalized with abdominal pain suggestive of acute appendicitis. Signs, symptoms, and laboratory findings were analyzed for specificity, sensitivity, predictive value, and joint probability. The total joint probability, the sum of a true-positive and a true-negative result, was chosen as a diagnostic weight indicative of the accuracy of the test. Eight predictive factors were found to be useful in making the diagnosis of acute appendicitis. Their importance, according to their diagnostic weight, was determined as follows: localized tenderness in the right lower quadrant, leukocytosis, migration of pain, shift to the left, temperature elevation, nausea-vomiting, anorexia-acetone, and direct rebound pain. Based on this weight, we devised a practical diagnostic score that may help in interpreting the confusing picture of acute appendicitis.

Acute Disease↗
PubMed1984

Tracheal fenestration. An improved technique.

Tracheal fenestration consists of a skin-lined tracheocutaneous communication with two skin valves that provides rapid access to the tracheobronchial tree. The procedure was first described in 1956 but the operative technique is difficult, and results of the valvular stoma are complicated by poor healing and scar formation. For these reasons, I developed an improved technique with significant advantages over the original one. Certain physiologic considerations were discussed regarding the benefits of this operation. Tracheal fenestration has a sound basis in the treatment of respiratory insufficiency caused by chronic lung diseases with excessive secretion. It not only helps in the respiratory toilet of these patients but provides easy access for administration of oxygen and nebulized medications.

Humans↗
PubMed1981

Reciprocal incisions for closure of circular skin defects.

With the use of a circular incision, adequate safe margins are obtained and, at the same time, waste of sound skin is minimized. The main problem is that the resultant circular defect may prove to be very difficult to close. Several methods currently used to close a circular defect are described. The use of the reciprocal incisions provides a method of closure that adapts to the size of the lesion and to the anatomical characteristics of the skin. A detailed description of this technique is given for each of the reciprocal incisions (double S, bow tie, and combined V-incision). A geometrical analysis in reference to the size of th incision, waste of sound skin, length, profile, and plasticity of the suture line is presented. A model to measure the skin after closure of a circular defect is described. The real advantage in choosing one of the reciprocal incisions lies on the resultant profile and plasticity of the suture line. Finally, the practical application of the reciprocal incisions is discussed.

Dermatologic Surgical Procedures↗
PubMed1977

Modified Shumacker operation for correction of transposition of the great arteries.

Correction of the transposition of the great arteries can be accomplished with a modified Shumacker operation. This procedure has been demonstrated in cadavers to have many advantages over the techniques used by Mustard and by Angelini and Sandiford. At present these two operations provide the best clinical results in correction of transposition of the great arteries. The details of the modified Shumacker technique are described and the different advantages of this technique are discussed.

Catheterization↗
PubMed1976

Female sterilization using the tubal ring.

The surgical and early postoperative complications were evaluated in a study of 221 laparoscopies and 29 minilaparotomies in which tubal occlusions were performed with the application of tubal rings. For either procedure, complications were infrequent. None of the procedures had to be completed by another technique of tubal occlusion, and none of the patients required an extended hospitalization for the treatment of a complication. Among the 79 patients who have been followed up for more than 6 months, no pregnancies have been reported. The tubal ring technique appears to be safe and effective when used with either laparoscopy of minilaparotomy.

Adult↗