Biomedical subjects

T R Silveira

Publications and source records attributed to T R Silveira.

At least 19 recordsLinked to original sources

PubMed2004

Management of vascular complications after pediatric liver transplantation.

Sixty-five children underwent liver transplantation (LTx) from March 1995 to December 2002. Cirrhosis due to biliary atresia was the main indication, and hepatic artery thrombosis (HAT) the most common vascular complication (n = 5). Other vascular problems were portal vein thrombosis and stenosis. Another patient developed hepatomegaly and ascites due to a late stenosis of the left hepatic vein anastomosis. The two cases of venous stenosis were successfully treated by percutaneous angioplasty. One graft with HAT was saved, but four children died awaiting retransplant.

Adolescent↗

PubMed2002

Hepatitis C virus infection and assisted reproduction.

BACKGROUND: In assisted reproduction, hepatitis C virus (HCV) transmission may pose a risk for the baby, technicians, and gametes or embryos from non-contaminated parents. This study aimed at determining the prevalence and risk factors for HCV infection in a group of infertile couples. METHODS: HCV infection was investigated in 409 patients attending the infertility clinic at Hospital de Clínicas de Porto Alegre, Brazil, between 1997 and 1998. Serum was screened for anti-HCV using ELISA and for hepatitis B surface antigen (HBsAg) using an enzyme-linked fluorescent assay (ELFA). HCV infection and semen viraemia was also investigated using HCV RNA detection. RESULTS: The overall prevalence of anti-HCV was 3.2% (8/248) among women and 3.7% (6/161) among men. All subjects were negative for hepatitis B virus (HBV) and human immunodeficiency virus (HIV). From the 14 HCV-positive patients, two were lost, and serum was collected from the remaining 12 patients for assessment of HCV RNA, resulting in five HCV-positive cases (one woman and four men). Only one of the HCV-positive men had viraemia levels >500 000 RNA copies/ml. There was a significant risk associated with being HCV-positive in women with HCV-positive male partners (P < 0.001). In male patients, the correlation between use of intravenous drugs and HCV-positivity was also significant (P < 0.001). CONCLUSIONS: Since the risk for vertical and laboratory HCV infection is not well determined, and HCV prevalence is not negligible in this group, we recommend that infertile patients be screened before assisted reproductive techniques.

Adolescent↗

PubMed2002

Potentiation of carbon tetrachloride hepatotoxicity by pentosan polysulfate in rats.

Few data are available in the literature regarding the effect of pentosan polysulfate (PPS) on normal and fibrotic rat livers. In addition, the combination of PPS and carbon tetrachloride (CCl4) has not been studied so far. The objective of this study was to assess the effect of PPS on rat livers treated or not with CCl4 for the induction of liver fibrosis. The study consisted of four stages: 1) hepatic fibrosis induction with CCl4 (N = 36 rats); 2) evaluation of the effect of PPS on CCl4-induced hepatic fibrosis (N = 36 rats); 3) evaluation of the effect of higher doses of PPS in combination with CCl4 (N = 50 rats); 4) evaluation of the presence of an enzymatic inductor effect by PPS (N = 18 rats) using the sodium pentobarbital test which indirectly evaluates hepatic microsomal enzyme activity in vivo. Adult (60 to 70 days) male Wistar rats weighing 180 to 220 g were used. All animals receiving 0.5 ml 8% CCl4 (N = 36) developed hepatic fibrosis, and after 8 weeks they also developed cirrhosis. No delay or prevention of hepatic fibrosis was observed with the administration of 5 mg/kg PPS (N = 8) and 1 mg/kg PPS (N = 8) 1 h after the administration of CCl4, but the increased hepatotoxicity resulting from the combination of the two substances caused massive hepatic necrosis in most rats (N = 45). PPS (40 mg/kg) alone caused hepatic congestion only after 8 weeks, but massive hepatic necrosis was again observed in association with 0.5 ml CCl4 after 1 to 4 weeks of treatment. Unexpectedly, sleeping time increased with time of PPS administration (1, 2, or 3 weeks). This suggests that PPS does not function as an activator of the hepatic microsomal enzymatic system. Further studies are necessary in order to clarify the unexpected increase in hepatotoxicity caused by the combination of CCl4 and high doses of PPS, which results in massive hepatic necrosis.

Animals↗

PubMed2000

[Liver transplantation]

OBJECTIVE: To review the clinical aspects and the theoretical basis of liver transplantation in children, focusing mainly pre and post surgical periods. METHODS: References were obtained from computerized search in the National Library of Medicine (Medline), recent review articles, and personal files. RESULTS: Great development has occurred in surgical techniques, in organ preservation, in postoperative care, and in immunosuppression methods after the first liver transplantation surgery took place in a child with biliary atresia in 1963. Liver transplantation has become an efficient therapy, widely accepted and used in all age groups. It is a very complex procedure, with many professionals involved and with several legal, ethical and economical implications. We review in this article the clinical aspects before transplantation, including indications, contraindications, clinical and laboratory evaluations, as well as postsurgical aspects, both in the immediate period, after the 1st week, and the long-term outcome, discussing the complications and the treatment of each. CONCLUSIONS: Liver transplantation has dramatically improved the survival of pediatric patients with chronic hepatic diseases. Patients of liver transplantation in the pediatric age group present today survival rates of 90% in the different transplantation centers.

Journal Article↗

PubMed1999

Hepatitis B seroprevalence in Latin America.

The seroprevalence of hepatitis B was investigated in over 12,000 subjects in six countries of Latin America: Argentina, Brazil, Chile, the Dominican Republic, Mexico, and Venezuela. Each study population was stratified according to age, gender, and socioeconomic status. Antibodies against hepatitis B core antigen (anti-HBc) were measured in order to determine hepatitis B infection. The highest overall seroprevalence was found in the Dominican Republic (21.4%), followed by Brazil (7.9%), Venezuela (3.2%), Argentina (2.1%), Mexico (1.4%), and Chile (0.6%). In all the countries an increase in seroprevalence was found among persons 16 years old and older, suggesting sexual transmission as the major route of infection. In addition, comparatively high seroprevalence levels were seen at an early age in the Dominican Republic and Brazil, implicating a vertical route of transmission.

Adolescent↗

PubMed1998

Histopathological diagnosis of intra- and extrahepatic neonatal cholestasis.

The histopathology of the liver is fundamental for the differential diagnosis between intra- and extrahepatic causes of neonatal cholestasis. However, histopathological findings may overlap and there is disagreement among authors concerning those which could discriminate between intra- and extrahepatic cholestasis. Forty-six liver biopsies (35 wedge biopsies and 11 percutaneous biopsies) and one specimen from a postmortem examination, all from patients hospitalized for neonatal cholestasis in the Pediatrics Service of Hospital de Clínicas de Porto Alegre, were prospectively studied using a specially designed histopathological protocol. At least 4 of 5 different stains were used, and 46 hepatic histopathological variables related to the differential diagnosis of neonatal cholestasis were studied. The findings were scored for severity on a scale from 0 to 4. Sections which showed less than 3 portal spaces were excluded from the study. Sections were examined by a pathologist who was unaware of the final diagnosis of each case. Bile tract permeability was defined by scintigraphy of the bile ducts and operative cholangiography. The F test and discriminant analysis were used as statistical methods for the study of the hepatic histopathological variables. The chi-square method with Yates correction was used to relate the age of the patients on the date of the histopathological study to the discriminatory variables between intra- and extrahepatic cholestasis selected by the discriminant function test. The most valuable hepatic histopathological variables for the discrimination between intra- and extrahepatic cholestasis, in decreasing order of importance, were periportal ductal proliferation, portal ductal proliferation, portal expansion, cholestasis in neoductules, foci of myeloid metaplasia, and portal-portal bridges. The only variable which pointed to the diagnosis of intrahepatic cholestasis was myeloid metaplasia. Due to the small number of patients who were younger than 60 days on the date of the histopathological study (N = 6), no variable discriminated between intra- and extrahepatic cholestasis before the age of 2 months and all of them, except for the portal expansion, were discriminatory after this age. In infants with cholestasis, foci of myeloid metaplasia, whenever present in the liver biopsy, suggested intrahepatic cholestasis. Periportal ductal proliferation, portal ductal proliferation, portal expansion, cholestasis in neoductules, portal cholestasis and portal-portal bridges suggested extrahepatic obstructive cholestasis.

Biliary Atresia↗

PubMed1993

Association between HLA and extrahepatic biliary atresia.

The etiopathogenesis of extrahepatic biliary atresia (EHBA) remains undefined. There are clinical and pathological suggestions supporting the idea that EHBA could consist of at least two forms: the congenital (embryonic or fetal) and the acquired (perinatal) types. To test the hypothesis that susceptibility to this disease would be influenced by host genetic factors, we studied the human leukocyte antigen (HLA) system in 55 patients with and without major extrahepatic congenital anomalies. We found, especially in those without associated malformations, a significantly higher frequency of HLA-B12, of haplotypes A9-B5 and A28-B35, and of their disequilibrium values, as compared with the 8th International Histocompatibility Workshop controls. This study suggests that immunogenetic factors may play a role in determining susceptibility to EHBA, and the different HLA frequencies in those with and without anomalies lend support to the hypothesis that biliary atresia may be an etiologically heterogeneous disorder.

Biliary Atresia↗

PubMed1992

The relative importance of familial, reproductive and environmental factors in biliary atresia: etiological implications and effect on patient survival.

1. The clinical records of 237 patients with extrahepatic biliary atresia (EHBA) attending King's College Hospital, London, between March 1973 and October 1985 were analyzed in terms of familial and reproductive factors, as well as of their possible effect on patient survival. 2. The male:female ratio was 0.93, and the ages of the patients' mothers and fathers were significantly higher than would have been expected from sibship data. Similarly, the number of first-born children having EHBA was less than expected. 3. In a subsample of 189 mothers, the obstetrical histories of women who had children with associated EHBA (20% of the total) showed: 1) a higher frequency of illness before and during pregnancy; 2) a higher level of pharmaceutical drug consumption during pregnancy, and 3) more fetal losses, especially in the gestation immediately preceding the patient's birth. 4. Age at death (average 15.1 +/- 13.2 months) and survival rates depend critically on surgical intervention and were not related to the presence or absence of extrahepatic malformations or to the type of atresia. 5. The present observations, taken together with those of others, indicate that problems in the reproductive process or exposure to noxious environmental agents may be etiological factors in associated EHBA.

Adolescent↗

PubMed1991

Congenital structural abnormalities in biliary atresia: evidence for etiopathogenic heterogeneity and therapeutic implications.

The clinical, surgical, laboratory and histological data of 237 children with extrahepatic biliary atresia were reviewed. Forty-seven patients (20%) had associated congenital anomalies, and of these, 28 had cardiovascular, 22 digestive and 19 splenic malformations. Of the 19 patients with splenic malformations, 13 showed the polysplenia syndrome and two had asplenia. Chromosome studies were performed in eight children, six having associated anomalies, and two of them showed karyotype abnormalities (46,XX,del 18 p- and 49,XXXXY). These observations indicated that biliary atresia could be subdivided into four distinct etiopathogenic subgroups, three involving a congenital form that could arise through a malformation, a disruption or a chromosome abnormality, and the remaining to agents active in the perinatal period (the acquired form). The surgical outcome in 171 patients operated on by an experienced surgeon was not influenced by the presence of anomalies but by the timing of surgery. Seventy-one percent of 24 patients operated on by 8 weeks of age were jaundice-free as opposed to only 34% of those who had later surgery (p less than 0.01).

Abnormalities, Multiple↗

PubMed1991

A randomized trial of chemotherapy followed by pelvic radiation therapy in stage IIIB carcinoma of the cervix.

Because of the poor results in stage III B carcinoma of the cervix with standard treatment using radiotherapy alone, we designed a randomized trial to determine whether administration of chemotherapy before pelvic irradiation would improve survival. Between May 1984 and August 1986, 107 patients with previously untreated squamous cell carcinoma were randomly assigned, after stratification by age (less than 50 v greater than 50 years), extent of parametrial involvement (unilateral v bilateral), and lymphangiographic findings (negative v positive) to pelvic radiotherapy (RT; arm A) or three cycles of chemotherapy (CT; bleomycin, vincristine, mitomycin, and cisplatin [BOMP]), followed by the same radiotherapy regimen (CT + RT; arm B). The groups were balanced by age, performance status, extent of parametrial involvement, bulkiness of cervical disease, nodal involvement, and presence of hydronephrosis. Minimal follow-up is 34 months. A complete local response was observed in 32.5% of the patients in arm A and in 47% of the patients in arm B (P = .19). Overall 5-year survival rates were 39% for the RT arm and 23% for the CT + RT approach (P = .02). Toxicity was severe in arm B and included fatal pulmonary toxicity in four patients. Locoregional and distant failures were similar in both groups. We conclude that, despite a satisfactory response rate, neoadjuvant BOMP chemotherapy adversely affects survival in stage III B cervical cancer and is associated with unacceptable toxicity.

Aged↗

PubMed1991

Extrahepatic biliary atresia and twinning.

1. Four pairs of discordant twins were observed in a series of 237 extrahepatic biliary atresia patients ascertained in London. 2. The twinning prevalence (1.7%) was as expected considering the ethnic composition of the sample. 3. Out of a total of 17 other twin pairs reported in the literature, only one was concordant for the disease. Since only 17 instances of familial cases have been described, the conclusion is that any influence of genetic factors in this condition is likely to be manifested indirectly, possibly in the form of increased susceptibility of the biliary epithelium to infectious or toxic agents.

Biliary Atresia↗

PubMed1986

Adenoid cystic carcinoma of salivary glands. A study of 61 cases with clinicopathologic correlation.

Sixty-one cases of adenoid cystic carcinoma of the head and neck region, excluding the ear canal, lacrimal glands, larynx, esophagus, and trachea, were studied, and their different clinicopathologic aspects were analyzed. Adenoid cystic carcinoma occurred more commonly in the minor salivary glands; the palate was affected in 31% of the cases. The fifth decade of life was the age at which patients were most commonly affected, and there was a slight predominance of white women. In most patients a mass was the main complaint; in 63% the duration of symptoms was 1 year or less. Forty-one patients had Stages 3 or 4 disease when first seen, and 51.7% of the patients died of disease, with a mean survival period of 35.4 months. Three basic patterns of growth, solid, cribriform, and tubular, were identified in the histopathologic examination of the cases. Other pathologic aspects analyzed were cellular pleomorphism, mitotic activity, necrosis, vascular invasion, and perineural infiltration. The study revealed a positive correlation between location of the tumor, clinical staging, duration of symptoms, and histologic pattern of growth with the prognosis of the lesion. Tumors located in the minor salivary glands, those in which the duration of symptoms was less than 1 year, and those that showed advanced clinical staging and a predominantly solid pattern of growth had an extremely poor prognosis. Surgery is the treatment of choice of adenoid cystic carcinoma, and microscopically free surgical lines of resection must be obtained. Radiation therapy, although not curative, plays an important role in prolonging survival.

Adolescent↗

PubMed1983

Upper gastrointestinal fiberoptic endoscopy in pediatric patients.

Upper gastrointestinal fiberendoscopy in pediatric patients is done safely and under local anesthesia in most instances. This study of 47 children confirmed the value of fiberendoscopy in establishing the etiology of upper gastrointestinal hemorrhage and the presence of esophageal varices. It also contributed significantly to the management of patients with disphagia, pyrosis, epigastric pain, and ingestion of foreign bodies. No significant morbidity was caused.

Abdomen↗

PubMedDate not supplied

Mucoepidermoid carcinoma of salivary glands: a clinicopathologic study of 46 cases.

Forty-six cases of mucoepidermoid carcinoma (MEC) of the salivary glands were reviewed with an emphasis on the clinicopathologic aspects and prognosis of the tumors. MEC occurred in a wide age range, with few cases being diagnosed in childhood. Its peak of incidence was in the fifth decade and it involved major and minor salivary glands with equal frequency; the parotid gland was the gland most commonly affected. Presence of a mass was the most common complaint of all 46 patients. About 64% of the patients presented with stages 3 and 4 disease. Three distinct histologic grades were found after analyzing cellular pleomorphism, mitotic activity, and presence of necrosis. This study showed that clinical staging and histologic grading are the most important factors influencing survival and they seem to be independent of each other. Other variables found to be important in prognosis were age, sex, and the development of recurrent disease after surgery. Surgery with total resection of the tumor was the most effective treatment in our cases and adjuvant radiotherapy proved to be of little value in improving survival of MEC in our series of cases, considering that the patients in whom this type of treatment was used had unfavorable clinicopathologic factors.

Adolescent↗

PubMedDate not supplied

[Hepatitis A and hepatitis B seroprevalence in 4 centers in Brazil].

The prevalence of antibodies to hepatitis A and B virus was assessed in 3,653 subjects across four regions of Brazil. The anti-HAV and anti-HBc seroprevalence were 64.7% and 7.9%, respectively. The highest anti-HAV (92.8%) and anti-HBc (21.4%) rates were seen in the Northern region. In other regions, anti-HAV seroprevalence over 90% was only reached in the more elderly, indicating an intermediate endemicity and a significantly higher anti-HAV prevalence was seen in the low socioeconomic group between 1-30 years. With respect to anti-HBc seroprevalence an increase was seen in adolescents and there was a significantly higher anti-HBc prevalence in the lower socioeconomic group between 1-20 years. A 3.1% anti-HBc prevalence was seen in one-year-old infants, suggesting a vertical transmission. The major findings of this study indicate that the pre-adolescent and adolescent population in some Brazilian cities are at greatest risk from both hepatitis A and B infection, but for different reasons.

Adolescent↗

PubMedDate not supplied

[Soroepidemiology of Varicella in Brazil - results of a prospective cross-sectional study]

OJECTIVES: Varicella has more serious consequences in adolescents and adults. Recent reports from Europe and Asia show an increasing number of adolescents and young adults being seronegative. As there is only limited data on varicella zoster virus (VZV) seroprevalence in Brazil and to facilitate the strategy for varicella vaccination we conducted a VZV seroprevalence study in Brazil. METHODS: This population-based, cross sectional seroepidemiology study was performed in 4 different regions of Brazil. The studied population was stratified according to gender, age and socioeconomic status. VZV IgG antibodies were analyzed by ELISA. RESULTS: 3,879 subjects aged 1-40 years were included into the study. The overall anti-VZV seropositivity rate across all age groups and centers in Brazil was 85.4%. There was a strong age relationship. Especially in the South East and South seroprevalence was low in the age group 1-5 years (44.5% and 57.8%, respectively) while in the North the rate was 88.9%. Overall, Varicella infection was independent of the socioeconomic level, but in the youngest age groups (1-10 years) seroprevalence rates were significantly lower in the high/medium socioeconomic class for most regions. Clinical history of chickenpox correlates well with anti- VZV seropositivity with a predictive value of 95.1% CONCLUSIONS: In preadolescence a substantial proportion of the Brazilian population is susceptible to Varicella infection, and a considerable part of the adolescents and young adults remain VZVseronegative and are thus also at risk.

Journal Article↗

PubMedDate not supplied

[Polysplenia syndrome associated to neonatal hepatitis]

OBJECTIVE: To report the unusual association between neonatal hepatitis and polysplenia syndrome.METHODS: Clinical, biochemical, histopathological, surgical and image analysis methods were used.RESULTS: The 36 days old patient presented hyperbilirubinemia with increase of direct reacting bilirubin and high alkaline phosphatase. The physical examination evidenced jaundice and hepatomegaly. The chest X-ray showed situs inversus and dextrocardia. Abdominal ultrasonography presented an increase in liver volume, mainly at the right lobe. There were two cystic lesions at the liver with absence of intrahepatic biliary tract dilatation. Absence of splenomegaly. Biliary scintigraphy didn't show any excretion of radioisotope to the duodenum while transoperative cholangiography presented contrast medium flowing to the duodenum lumen. During laparotomy it was possible to observe polysplenia, abdominal aorta to the right of the lower vena cava, gallbladder at the left lobe of the liver, appendix on the left side of the abdomen and sigmoid colon on the right side. The hepatic wedge biopsy was compatible with idiopathic neonatal hepatitis.CONCLUSION: The finding of polysplenia syndrome in patients with neonatal cholestasis doesn't necessarily indicate the recurrent presence of extrahepatic biliary atresia.

Journal Article↗

PubMedDate not supplied

[Follow-up of pediatric patients evaluated for liver transplantation].

OBJECTIVE: To analyze the evolution of pediatric patients chosen for hepatic transplantation. METHODS: A review was made of the clinical charts of the first 65 children and adolescents with chronic liver disease, aged 5 months to 19 years (X = 6.8%), chosen for liver transplantation during the period of August 1994 to March 1996. Data refer to the patients' demographic characteristics, etiology of their liver disease, their psychosocial situation and of their parents, and their clinical and laboratorial evaluation. According to the severity of the disease, patients were classified as active (waiting for a donor), in evaluation, inactive (compensated liver disease), and excluded for psychosocial or medical conditions, or because of bad indication. RESULTS: Eight patients (12%) received transplantation, and one of them died. Seven (11%) died when in evaluation or waiting for a donor. Ten patients (15%) were excluded from the waiting list: 6 for social problems, and 4 for medical problems. No patient was excluded for bad indication. Six patients are in the active list, waiting for donor. The other 23 patients (35%) are in evaluation, and 11 (17%) are classified as inactive in the waiting list. CONCLUSIONS: Eleven patients (17%) were not operated on due to the advanced stage of the liver disease. We emphasize the necessity of organ donation, and the early contact of the patients with a reference center.

English Abstract↗