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Biomedical subjects

C Diaz

Publications and source records attributed to C Diaz.

At least 109 records · Page 6Linked to original sources
PubMed1992

Indications and results of hepaticojejunostomy in benign strictures of the biliary tract.

The postoperative and late results of 99 patients with benign strictures of the biliary tract are presented. Patients were classified according to Bismuth into 24 cases with lesion type I, 36 cases with type II, 35 cases with type III and 4 patients with type IV. All were submitted to hepaticojejunostomy with a long Roux-en-Y loop. The etiology of the strictures varied according to the type of stricture. In patients of type I, inflammatory and iatrogenic causes were observed. Among type II and III patients, previous cholecytocholedochal fistulas were the main cause, together with accidental section or ligature of the common bile duct. Operative mortality was absent in strictures of types I and II, while it was around 25% in cases of types III and IV. At late control, the best results were seen among patients with strictures of types I and II. We believe that the main factor determining the early and late outcome of these cases with benign strictures is the location of the stricture and the quality of the proximal duct.

Adult↗
PubMed1991

Attachment of Trypanosoma cruzi trypomastigotes to receptors at restricted cell surface domains.

We have used glutaraldehyde-fixed target cells to study the attachment phase of cell invasion by live trypomastigotes of Trypanosoma cruzi, and determined that attachment is polarized and receptor-mediated. T. cruzi trypomastigotes bind much less efficiently to confluent epithelial cells, which are polarized, than to sparse epithelial cells. When the tight junctions of confluent epithelial cells are disrupted by removing Ca2+ from the incubation medium before glutaraldehyde fixation, binding of T. cruzi increases. T. cruzi also shows preference for attachment underneath cells or to the edges of cells. The binding occurs within a few minutes, is saturable, and is influenced by the parasite developmental stage. Fab fragment derived from monoclonal antibodies that immunoprecipitate a 160-kDa molecule present only on the surface of trypomastigotes inhibit adhesion to fixed and live cells. Future characterization of the target cell receptors for this molecule and the use of fixed target cells should facilitate studies of the mechanisms involved in the initial interaction of T. cruzi with its host cells.

Animals↗
PubMed1991

Increased growth of myoblasts from hypertrophic muscles in syringomyelia.

Proliferation and differentiation of myoblasts from hypertrophic muscles were studied "in vitro" in two cases of syringomyelia with muscle hypertrophy (MH). Their myoblast growth was compared with that of muscle cells sampled on the contralateral side in the same patients and in control subjects. The effect of a circulating factor was tested using patient sera in place of fetal calf and horse sera. The results showed that MH cells were morphologically abnormal (giant and granular). MH myoblasts proliferated more rapidly than contralateral and normal myoblasts, their fusion was accelerated and the resulting myotubes synthesized higher levels of protein. MH sera increased these effects. Serum factors are therefore likely to be involved in "in vivo" muscle hypertrophy. These findings suggest that the pathogenesis of muscle hypertrophy in syringomyelia involves acquired abnormalities due to molecules released in response to neural lesions.

Adult↗
PubMed1991

Argentina's WHO Cancer Pain Relief Program: a patient care model.

We treat cancer pain patients at their homes, in collaboration with their relatives and primary physician. Assistance is free. Our team is monodisciplinary and trained volunteers are the liaison between team and patients. In 118 patients treated with our model between October 1987 and December 1988, we assessed the symptoms that moved them to seek assistance, their previous therapies, and the effectiveness of our intervention. The data obtained suggest that (a) in our country, the majority of cancer patients do not obtain effective pain and symptom control; (b) our model yields satisfactory pain control and improvement in quality of life; and (c) there is a need for centers that teach and practice terminal care; our model may be useful as a working outline for such centers.

Argentina↗
PubMed1991

Malathion and pyrethroid resistance in Culex quinquefasciatus from Cuba: efficacy of pirimiphos-methyl in the presence of at least three resistance mechanisms.

Use of malathion for mosquito control in Cuba for 7 years up to 1986 has selected for elevated non-specific esterase and altered acetylcholinesterase (AChE) resistance mechanisms in populations of the pest mosquito Culex quinquefasciatus Say. These mechanisms are still present in relatively high frequencies in the Havana area, despite the replacement of malathion by pyrethroid insecticides for the last 3 years in the mosquito control programme. Samples of Culex quinquefasciatus populations from within a 100 km radius of Havana had high levels of resistance to malathion and lower levels of resistance to propoxur, but there was little or no cross-resistance to the organophosphorus insecticide pirimiphos-methyl. Selection with malathion for twenty-two consecutive generations in the laboratory increased the level of malathion resistance to 1208-fold and propoxur level to 1002-fold, but the maximum level of pirimiphos-methyl resistance was only 11-fold. Pirimiphos-methyl is still operationally effective, despite the resistance mechanisms segregating, so this insecticide if used for control is unlikely to select either of the known resistance factors directly in the field population. Since 1986, pyrethroids have been used extensively, and low levels of pyrethroid resistance were detected in two of five field population samples tested. Malathion selection did not increase the level of pyrethroid resistance, which indicates that one or more distinct pyrethroid resistance factors are now being selected in the field populations of Culex quinquefasciatus.

Aerosols↗
PubMed1990

Antilymphoblast globulin, cyclosporine, and steroids in cadaveric renal transplantation.

In order to avoid cyclosporine (CsA) nephrotoxicity and rejection, especially during the early posttransplant periods, different immunosuppression regimens have been adopted. A prospective trial was conducted to evaluate the benefits of initially low CsA doses associated with antilymphoblast globulin and steroids in the first days after transplant, in comparison with higher doses of CsA and steroids. Between 1/86 and 1/88, two groups of first-cadaver renal transplant recipients were documented based on the immunosuppression regimen used. In group A (n = 50), oral CsA was started at 8 mg/kg/day and subsequent doses adjusted to maintain CsA whole-blood levels between 300 and 600 ng/ml. Horse ALG at 10 mg/kg was given the day after transplant and on alternate days to a maximum of 6 doses. After 3 doses, ALG was stopped if CsA blood levels were equal to or greater than 400 ng/ml. ALG dosage modifications were made in order to maintain peripheral CD3+ cells between 10 and 20%. Prednisone was given at 0.25 mg/kg/day. In group B (n = 50), oral CsA was started at 15 mg/kg/day. The CsA whole-blood levels were maintained between 300 and 800 ng/ml. Prednisone was administered at 0.5 mg/kg/day. The incidence of postransplant renal failure was the same in both groups (16%), but the duration of oliguria was lower in group A than in group B (3.3 +/- 2 vs. 16.2 +/- 10.7 days, P less than 0.05), as well as the incidence of acute rejection during the first 3 months (18% vs. 40%, P = 0.01. The cumulative doses of CsA and steroids were significantly lower in group A than in group B. Mean serum creatinine at 6 and 12 months remained similar in both groups. There was no difference between the 2 groups in the incidence of infection. There was no mortality in either group. The actuarial graft survival was significantly higher in group A than in group B at one (100% vs. 94%), two (97% vs. 87%), and three years (89% vs. 73%), respectively (P = 0.041). In summary, the triple regimen using simultaneously low-dose CsA, ALG, and steroids minimizes early graft dysfunction, provides efficient immunosuppression without severe infections, and gives good long-term patient and graft survival.

Adult↗
PubMed1990

A prospective study of chronic or recurrent headache in systemic lupus erythematosus.

This study was conducted to analyze the prevalence and features of chronic or recurrent headache in Systemic Lupus Erythematosus (SLE), and also the relationship of such headache with other manifestations of the disease. A total of 76 patients (69 women and 7 men) with a mean age of 40 years (r: 24-74 years) were included. An overall severity index for SLE was applied. Fifty-two patients (68%) presented headache, 27 (52%) being vascular and 25 (48%) muscle contraction type. Headache in general was more frequent after the onset of SLE (p less than .001). Prevalence of muscle contraction headache in particular was greater following manifestations of SLE. Family history of migraine was recorded in 54% of the patients with vascular headache. This antecedent was more common in patients in whom migraine started before the onset of SLE (p = .05). A greater number of neuropsychiatric symptoms was observed in the patients with vascular headache and family history (p less than .02). Patients with thrombocytopenia presented headache less frequently (p less than .05). Our results showed headache, of both vascular and muscle contraction types, to be frequent in SLE. We note that there is an increased frequency of muscle contraction headache after the onset of SLE, and that there is a migraine-like headache directly related to SLE. Migrainous patients with familial history have a greater probability to suffer neuropsychiatric manifestations. Finally, it is suggested that severity of SLE is not related to presence of headache.

Adult↗
PubMed1990

Application of a new phased-array ultrasound imaging catheter in the assessment of vascular dimensions. In vivo comparison to cineangiography.

Tomographic imaging techniques such as ultrasound can provide important information in the evaluation of vascular anatomy. Recent technical advances have permitted fabrication of a small (1.83 mm), phased-array, intravascular ultrasonic imaging catheter capable of continuous real-time, cross-sectional imaging of blood vessels. We used this imaging catheter to compare intraluminal ultrasound with cineangiography in the measurement of vascular dimensions in animals and to assess the intraobserver and interobserver variability of the technique. Segmental deformation of vessel anatomy was produced by stenoses created with a tissue ligature or by balloon dilation. The mean value for measurements of vessel diameter was 5.6 mm by cineangiography and 5.7 mm by intravascular ultrasound. The correlation between cineangiography and ultrasound was close (r = 0.98). Mean cross-sectional area by angiography was 28.8 mm2 and 29.6 mm2 (r = 0.96) by ultrasound. Percent diameter reduction produced by the stenoses averaged 48.4% by cineangiography and 40.1% by ultrasound, and the two methods correlated closely (r = 0.89). Correlation between cineangiography and ultrasound for vessel diameter and area before balloon dilation was closer (r = 0.92 and 0.88) than after balloon dilation (r = 0.86 and 0.81). This difference reflected an increase in measured vessel eccentricity following balloon dilation. These data demonstrate that intravascular ultrasound is an accurate and reproducible method for measurement of vascular diameter and cross-sectional area in vivo. Intravascular ultrasound is capable of accurately identifying and quantifying segmental deformation of vascular dimensions produced by either stenoses or balloon dilation.

Angioplasty, Balloon↗
PubMed1989

Recovery of motile sperm using the migration-sedimentation technique in an in-vitro fertilization-embryo transfer programme.

Sperm washing techniques, based on the swim-up principle used before inseminating the human oocyte in in-vitro fertilization and embryo transfer programmes (IVF-ET), usually require prior centrifugation which causes damage to the sperm cell. A technique is described for separating sperm at laboratory temperature based on sperm migration--sedimentation principles, using two concentric tubes and recovering 70-90% forward-moving cells. A group of 17 patients is presented who were managed with this method. The results were 85% fertilization rate, 4% polyspermia and six clinical pregnancies.

Cell Separation↗
PubMed1989

Neuronal typology of Gallotia galloti optic tectum.

The object of this work has been to show neuronal typology and stratification of the optic tectum in Gallotia galloti adult specimens so as to have a basic model for the neuronal genesis study. As methodology Nissl and Golgi-Stensaas technique were employed. Six strata have been identified that include 14 layers where the neuronal types can be included, poligonals, bipolar, monopolar and stellate types. The stratification of the optic tectum in the 14 layers is corroborated in Reptiles, a fact which is maintained in birds, and is reduced in amphibians, urodels, and fish here the reptil optic tectum presentes an extraordinary importance in the study of the auditive and visual vias in phylogeny.

Animals↗
PubMed1989

Synthesis and apparent secretion of prothymosin alpha by different subpopulations of calf and rat thymocytes.

Prothymosin alpha (ProT alpha), a polypeptide containing the sequence of thymosin alpha 1 (T alpha 1) at its NH2-terminus, has been isolated from calf thymocytes in a concentration in the order of that found in the whole thymic gland. As deduced from the analysis of their tryptic peptides, calf ProT alpha differs from the rat polypeptide at least in an alanine residue replacing valine at position 92. Thymocytes cultured in a radioactive medium exhibit an important secretory activity, ProT alpha being one of the products synthesized and exported to the culture medium. Large and small thymocyte subpopulations from calf and rat differ in their capacity to synthesize ProT alpha. The polypeptide is produced in a major concentration by large thymocytes. However, all the calf and rat thymocyte subpopulations show a similar capacity to secrete ProT alpha, the amount of the newly synthesized polypeptide recovered from cell culture supernatants being 80-90% of that found in thymocyte extracts.

Animals↗
PubMed1986

Caffeine intensifies taste of certain sweeteners: role of adenosine receptor.

Caffeine, a potent antagonist of adenosine receptors, potentiates the taste of some but not all sweeteners. It significantly enhances the taste of acesulfam-K, neohesperidin dihydrochalcone, d-tryptophan, thaumatin, stevioside, and sodium saccharin. Adenosine reverses the enhancement. Caffeine has no effect on aspartame, sucrose, fructose, and calcium cyclamate. These results suggest that the inhibitory A1 adenosine receptor plays an important local role in modulating the taste intensity of certain sweeteners and that several transduction mechanisms mediate sweet taste.

Adenosine↗
PubMed1986

Ill health and use of medical care. Community-based assessment of morbidity in children.

The purpose of this study was to assess the relationship between morbidity and ambulatory care utilization in a randomly selected sample of children with stable patterns of use of services in a prepaid multispecialty group practice. The unique features of the approach were a focus on long-term relationships (over 8 years) and on assessment of health status by a combination of parent reports, child reports, teacher reports, and physical examination. Domains of health status that were assessed included types and frequencies of health conditions and disability associated with them, functional status (physical health, mental health, social health, general well-being), school absence, vision and hearing screening, and physical abnormalities. Children with persistently high levels of use of services in a 6-year period (1974-79) were more likely to have health problems of all types, both concurrent and in a subsequent 2-year period (1980-81) than children with lower levels of use. As these findings were in agreement with those obtained in a study where morbidity was determined by diagnoses recorded in medical records, it is likely that the measures could be more generally useful to assess child health status in the community. Moreover, they distinguish groups of children who differ in their pattern of use of services and hence may be useful in the planning and budgeting of services for child populations.

Ambulatory Care↗
PubMed1986

Initial report of a mycotic aneurysm of the common iliac artery with compression of the ipsilateral ureter and femoral vein: a literature review and case report.

Iliac artery aneurysms are rare and the usual symptoms, pelvic pain and urological complaints, are nonspecific. We describe a patient with pelvic pain, intermittent urinary retention, and lower extremity edema. A right common iliac artery aneurysm was discovered during surgery after rupture had occurred. Pathologic examination revealed a mycotic process. This case demonstrates the obscure and unreported clinical features of iliac artery aneurysms. When this lesion is suspected, an angiogram should be performed promptly in an effort to prevent the predictable catastrophic consequences.

Journal Article↗