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Biomedical subjects

M Rivera

Publications and source records attributed to M Rivera.

At least 109 records · Page 6Linked to original sources
PubMed1996

Influence of hypertension on early renal insufficiency in autosomal dominant polycystic kidney disease.

To determine the potential effect of hypertension on early renal function deterioration, 30 patients (13 normotensive and 17 hypertensive) with autosomal dominant polycystic kidney disease and initially normal renal function were retrospectively analyzed. The decline in renal function was estimated by the slope of the linear regression of creatinine clearance versus time. Analysis was made in terms of standardized slope (slope divided by its standard deviation, i.e., measured in standard deviation units). In the hypertensive group the mean standardized slope was significantly higher than in the normotensive group (-10.89 and -4.98, respectively; p < 0.001). The average mean arterial pressure was significantly lower in the normotensive group with respect to the hypertensive one (95 and 109 mm Hg, respectively; p < 0.0001). There was a significant negative linear relationship between the average values of systolic, diastolic, and mean arterial pressures and standardized slopes. The best prediction equation for renal function deterioration was obtained using a multiple linear regression model in which independent variables were maximum and average diastolic pressures. Therefore, prior to renal insufficiency, a high arterial pressure had a significant contribution to renal function deterioration.

Adult↗
PubMed1996

Effect of rHuEpo therapy in dialysis patients on endogenous erythropoietin synthesis after renal transplantation.

UNLABELLED: We have undertaken a prospective study to examine the effect of recombinant human erythropoietin (rHuEpo) therapy during dialysis on Epo levels after renal transplantation and to evaluate the impact of this therapy on the immediate graft function. Between December 1991 and December 1993, 91 renal transplant recipients were studied. There were 34 females and 57 males and the mean age was 38 years. Forty-two patients were treated during dialysis with rHuEpo due to anemia and 49 patients did not receive it. Endogenous Epo (eEpo), hemoglobin concentration, hematocrit level and serum creatinine were determined on days 0, 2, 4, 8, 15, 30, 60 and 180 after transplantation. Ferritin level was determined pretransplant and on day 60. RESULTS: Patients not treated with rHuEpo during dialysis experienced a transient increase in endogenous Epo after renal transplant that was not observed in treated patients (26 +/- 3.3 vs. 9 +/- 1.5 mU/ml, p < 0.001). The eEpo peak was similar in patients with early or delayed graft function (23 +/- 4.3 vs. 32 +/- 5.4 mU/ml, NS). The recovery of the anemia after a successful renal transplant took place in patients treated as well as those not treated with rHuEpo without significant differences. In the treated group, the pretransplant hematocrit level was similar in patients with early or delayed graft function (31 +/- 3.5% vs. 32 +/- 4.8%), but in the untreated group, the hematocrit level was lower in patients with early renal function (28.5 +/- 4% vs. 32 +/- 3%, p < 0.05). However, these patients also had a significantly shorter warm ischemia time (53 +/- 13.8 vs. 64 +/- 14.5 min). Fifty-two percent of the rHuEpo-treated patients and 36% of the untreated patients had delayed graft function. In conclusion, different courses of eEpo levels after renal transplant were observed depending on whether or not patients had been treated with rHuEpo during dialysis. Untreated patients experienced a transient increase which was not observed in the treated group. Immediate or delayed graft function did not modify eEpo levels. No association was found between rHuEpo therapy during dialysis and delayed graft function.

Adolescent↗
PubMed1996

Treatment of posttransplant lymphocele with povidone-iodine sclerosis: long-term follow-up.

Percutaneous transcatheter sclerosis with iodate-povidone has been proposed as a treatment of posttransplant lymphocele. We treated 19 lymphoceles with iodate-povidone, 10 of them totally resolved and 6 promptly recurred. Three recurrences were treated conservatively and in 3 the treatment was repeated with success. Therefore, we have a low recurrence and retreatment rate. Our total resolution rate was 100%. Complications due to the treatment were rare. In the long term no patient has developed any renal or perirenal complication related to iodine sclerosis. We conclude that iodine sclerosis is a safe and effective treatment of posttransplant lymphocele. We think that surgical procedures must be reserved to collections adjacent to renal hilum or inaccessible for safe puncturing.

Follow-Up Studies↗
PubMed1996

Soluble adhesion molecules in renal transplantation.

Serum levels of sICAM-1 and sVCAM-1 adhesion molecules as well as TNF cytokine were measured in 50 kidney transplant recipients [14 patients with stable graft function, 18 patients with acute rejection, 10 patients with CsA toxicity, 6 patients with ATN, and 2 patients with cytomegalovirus (CMV) disease] during the first 3 postoperative weeks. All the patients studied showed, on the first posttransplant day, elevated serum levels of sICAM-1 (260 +/- 53 ng/mL). Interestingly, all the patients with good graft function presented thereafter a reduction of sICAM-1 serum levels close to the normal values (185.2 +/- 40 ng/mL). In contrast, the group of patients with acute allograft rejection showed significantly increased serum levels of sICAM-1 (371.5 +/- 86 ng/mL; p < 0.001), 3-4 days before diagnosis of acute rejection. Although sVCAM-1 levels were increased in both acute graft rejection (2263 +/- 106) and CsA toxicity (1650 +/- 315) patients, such increase was not significant among either group of patients when the group with CsA toxicity was compared with either ATN (1320 +/- 204) or stable renal function (1089 +/- 167). No statistical differences in the levels of TNF were demonstrated between the different groups of patients studied. Our findings demonstrate that quantitative determination of serum sICAM-1 may be of predictive clinical value in transplanted patients with acute renal allograft rejection.

Cyclosporine↗
PubMed1996

Lower Abdominal Pain in a Perimenarchal Adolescent.

A 13-year-old girl presented to the emergency department with a 5-day history of lower abdominal pain and dysuria that coincided with the onset of her last menstrual period. Menarche occurred 4 months previously and previous cycles were normal. The CAT scan of the abdomen and pelvis revealed a uterus didelphis with obstruction. Abdominal pain was due to hematocolpos and hematometra. The left hemivagina was distended with hematocolpos, and left renal agenesis was also noted. The vaginal septum was removed surgically without complications and she continued to be monitored closely.

Journal Article↗
PubMed1996

["Ex-situ" reconstructive surgery of the renal arteries].

The paper sums up our experience with kidneys which have undergone "bench" extracorporeal arterial surgery. The reasons making this procedure necessary were: renal graft from corpse donor presenting multiple arteries or arterial lesions (12 cases); orthoptic kidneys with stenotic lesions or arterial aneurism (5 cases); transplanted grafts which developed renal artery stenosis (2 cases). Incidence of arterial thrombosis and ureteral fistula was significantly higher in the first group than in grafts where no "bench" surgery had been performed. Medium- and long-term actuarial survival, however, showed no difference. In the second and third groups, extracorporeal arterial reconstructive surgery is a technique with a high risk for the loss of the involved renal unit.

Adolescent↗
PubMed1996

[Sclerotherapy of post-renal transplantation lymphocele with percutaneous instillation of amidotrizoate].

Incidence of post-renal transplant (RT) lymphocele varies between 0.6% to 41% depending on the author. Therapeutical management of these entities is controversial. (Open or laparoscopic) surgical marsupialization of the peritoneal cavity, percutaneous drainage, and percutaneous sclerosis with povidone-iodine are all valid options to treat post-RT lymphocele. This paper presents two cases of symptomatic post-RT lymphocele not suitable for laparoscopic treatment, which were resolved by intracavitary instillation of Sodium Amidotrizoate 76%. The first case had been previously treated with povidone-iodine with no resolution, also maintaining a 500 ml/24h deficit. In the second case, instillation with Sodium Amidotrizoate 76% was considered first choice approach. In both instances the lymphocele deficit ceased with instillation intervals of 6 and 14 days, respectively. In brief, percutaneous sclerosis with Amidotrizoate can be a valid alternative for the treatment of post-RT lymphocele.

Adult↗
PubMed1996

[Bartonella henselae infection in immunocompetent patients: cat scratch disease].

BACKGROUND: Cat scratch disease, whose etiologic agent is Bartonella henselae, is a benign disease in immunocompetent subjects, characterized by lymphadenopathy of prolonged course and occasional involvement of other organs such as liver, spleen, central nervous system, eye and lung. In immunocompromised patients, the infection is bacteremic and disseminated. AIM: To report Chilean cases of cat scratch disease. PATIENTS AND METHODS: Ten children (seven male, aged between 6 and 13 years old) with histologically or serologically confirmed cat scratch disease are reported. RESULTS: Lymphadenopathy location was pre auricular in four cases, axillary in two, inguinal in two and epitrochlear in two. Three children had fever over 39 degrees C and two had a parinaud syndrome. Nine children had a history of cat scratch and one of a cat byte. Six had an erythrocyte sedimentation rate over 40. Lymph node ultrasound examination was a useful diagnostic tool. Two patients had splenic granulomas. Lymph node biopsies were obtained in four cases, showing a suppurative granulomatous lymphadenitis in all and a positive Warthin-Starry stain in two. Serology, done in patients without histological confirmation was positive with titles ranging from 1:64 to 1:8192. All patients had a satisfactory outcome with regression of lymphadenopathy. CONCLUSIONS: Infections by Bartonella hemselae occur in the Chilean population and must be considered in the differential diagnosis of regional lymph node enlargement.

Adolescent↗
PubMed1995

Biosynthetic preparation of isotopically labeled heme.

An efficient method for the preparation of isotopically enriched heme has been developed. This method utilizes a commercially available bacterial host and plasmid, into which a synthetic gene encoding for rat liver outer mitochondrial membrane cytochrome b5, a heme-binding protein, has been inserted. The method described in this report utilizes the efficient synthesis of the cytochrome b5 polypeptide together with the enhanced biosynthesis of heme brought about by addition of the first committed precursor in heme biosynthesis, delta-aminolevulinic acid. Apocytochrome b5 sequesters heme as the macrocycle is being synthesized in order to form holocytochrome b5, thus avoiding toxic concentrations of free macrocycle in the cell. Relatively high concentrations of free heme in the cell have been shown to stimulate excretion of heme precursors such as coproporphyrinogen and uroporphyrinogen (W. F. Harris III, R. S. Burkhalter, W. Lin and R. Timkovich, (1993) Bioorg. Chem. 21, 209-220), therefore causing isotopic dilution of the labeled material. The heme obtained using this methodology was determined to be > 85% enriched. Because the heme in cytochrome b5 is not covalently attached to the polypeptide, it can be extracted and used in other applications. Use of glutamate, a precursor of delta-amino-levulinate biosynthesis in Escherichia coli, did not result in high levels of isotopic incorporation into heme, thus pointing out to the importance of using a labeled precursor that is committed to heme biosynthesis in order to obtain high levels of isotopic labeling.

Aminolevulinic Acid↗
PubMed1995

Clinical, pathophysiologic, and microbiologic characterization of bronchiectasis in an aging cohort.

STUDY OBJECTIVE: Awareness of bronchiectasis on the part of clinicians has been low in recent years, although it was previously well recognized. We believe that bronchiectasis is underdiagnosed, and that current literature is skewed toward the esoteric etiologies of bronchiectasis. DESIGN: We reviewed the clinical, radiologic, microbiologic, and physiologic findings in 123 well-studied patients with proved bronchiectasis. SETTING: The University of Texas Health Center at Tyler Hospital and Clinics. MEASUREMENTS AND RESULTS: There were 38 men and 85 women with a mean (+/- SD) age of 57.2 +/- 16.7 years; 55% were lifetime nonsmokers. Diagnosis was confirmed with CTs of the chest in 56%, by bronchogram in 28%, and surgery with the remainder. Seventy percent of patients gave a history of an antecedent potentially causative event for the bronchiectasis, usually pneumonia. Symptoms of bronchiectasis included chronic cough with the production of purulent sputum, hemoptysis, recurrent fever, and pleurisy. The finding of crackles on chest examination was the rule (70%) with wheezing present in 34% of the group. Pulmonary function studies documented airway obstruction to be present in 54% of the lifetime nonsmokers. The chest radiographs were abnormal in 91.3%, showing fibrotic stranding and infiltrates. A variety of pathologic microbial flora, particularly Pseudomonas aeruginosa and other opportunistic organisms, were isolated from the sputum. Patients who had smoked had much the same picture as nonsmokers, although they had a greater degree of airway obstruction. CONCLUSIONS: A characteristic clinical picture of bronchiectasis emerges after review and evaluation of these data. Knowledge of this picture should allow ready recognition of the disease.

Adult↗
PubMed1995

Prevalence and standardized incidence rates of preclinical cervical pathology among 1,061 women sterilized with transcervical quinacrine hydrochloride pellets.

OBJECTIVE: To determine whether the incidence of in situ cervical carcinoma was increased among a cohort of women who received transcervical insertions of quinacrine hydrochloride pellets into the uterine cavity as a method of nonsurgical sterilization. DESIGN: Retrospective review of Papanicolaou (Pap) test results, comparing incidence of high-grade lesions among quinacrine acceptors with a comparison population. SETTING: Outpatient clinics, Santiago, Chile. SUBJECTS: Women attending a family planning clinic (quinacrine acceptors) and a comparison population from another area of Santiago. MAIN OUTCOME MEASURE: Incidence of in situ cervical carcinoma. RESULTS: During 3,668 woman-years of follow-up, 8 women in the quinacrine group were found to have in situ carcinomas for an age-adjusted rate of 2.62 per 1,000 woman-years. The incidence in a comparison population was 1.62 per 1,000 woman-years, but the difference was not statistically different. CONCLUSIONS: The age-standardized incidence of in situ carcinoma among the quinacrine sterilized women was not significantly different from the rate in a comparison population of women in Santiago. However, the study has a number of limitations.

Adolescent↗
PubMed1994

Bacterial bronchitis and bronchiectasis in human immunodeficiency virus infection.

BACKGROUND: Bacterial pneumonia and sinusitis are important causes of morbidity in patients with human immunodeficiency virus (HIV) infection. We noted an increased incidence of bacterial bronchitis and bronchiectasis in our patients with HIV infection. METHODS: This study was conducted on persons with HIV infection at a county hospital and clinic. Bronchiectasis was diagnosed by bronchogram and computed tomography in one patient and by computed tomography alone in two others. Bacterial bronchitis was defined by a Gram's stain showing an abundance of neutrophils with a predominance of one or more bacteria and by a confirmatory sputum culture. Bronchoscopy with broncho-alveolar lavage was performed in patients with bronchitis to eliminate other causes of bronchial inflammation. RESULTS: Eighteen episodes of bacterial bronchitis in 10 patients are described. The mean CD4 lymphocyte counts for these patients was 0.061 x 10(9)/L (range, 0.001 to 0.203 x 10(9)/L). The most common pathogens in 18 episodes of bacterial bronchitis were Haemophilus influenzae and Streptococcus pneumoniae (five episodes each) and Pseudomonas aeruginosa (four episodes). Response to antibiotic therapy was usually rewarding though recurrences were frequent. Three patients with well-defined bronchiectasis who appeared to have developed, or who became symptomatic during the course of, HIV infection are described. Their mean CD4 cell count was 0.03 x 10(9)/L (range, 0.024 to 0.037 x 10(9)/L). Haemophilus influenzae, Staphylococcus aureus, Pseudomonas cepacia, and P aeruginosa were recovered from these patients; the P aeruginosa was a mucoid strain. CONCLUSIONS: Recurrent bacterial bronchitis should be added to the list of bacterial infections that occur with increased frequency with HIV infection. Repeated bacterial bronchitis may lead to bronchiectasis, which may be more common in HIV infection than generally appreciated.

Adult↗