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Biomedical subjects

J Ramirez

Publications and source records attributed to J Ramirez.

At least 19 recordsLinked to original sources
PubMed1992

Electrophysiological and morphological changes in rabbit retina after exposure to the light of the operating microscope.

Healthy adult rabbit eyes were exposed to up to 4 h of continuous illumination with moderate light intensity, as is produced by the lamp of an ophthalmic operating microscope. Electroretinograms were recorded before and after the long period of illumination. The depression of the waves in the electroretinograms observed just following light exposure recovered within 1 h to normal values. Electron microscopy of the retina revealed changes within the cells of the pigment epithelium. These results are discussed in view of their clinical implications in human patients.

Animals↗
PubMed1992

Chronic oral etoposide in non-small cell lung carcinoma.

25 consecutive inoperable or extended non-small cell lung cancer (NSCLC) patients (19 non-chemotherapy pretreated, 6 non-heavily pretreated) were given oral etoposide, 50 mg/m2/day for 21 successive days, every 4 weeks. 5 partial responses (PR), 9 disease stabilizations were achieved; the overall response rate of 20% (95% confidence interval, 4% to 36%) or 26% in non-pretreated patients. Median survival and PR duration probabilities were 6.7 months and 6.3 months, respectively. Alopecia excepted (96% of patients), non-haematological toxicity was mild. Haematological toxicity WHO grade II+III mainly consisted of leukopenia (28%).

Administration, Oral↗
PubMed1992

Effect of therapy with a new glucocorticoid, deflazacort, on linear growth and growth hormone secretion after renal transplantation.

Deflazacort is an oxazoline compound derived from prednisolone with similar antiinflammatory effects but fewer side effects. We studied changes in kidney function, growth velocity, weight/height ratio, and growth hormone secretion before and a year after substitution of deflazacort for methylprednisone in nine patients aged 9 to 15 years, 4 years after renal transplantation; all were in Tanner pubertal stage 1. Methylprednisone (mean +/- SEM: 0.2 +/- 0.02 mg/kg per day) was replaced by deflazacort (0.3 +/- 0.03 mg/kg per day) for a mean period of 15 months. Serum creatinine and calculated creatinine clearance did not change significantly during deflazacort treatment. Growth velocity increased from 1.5 +/- 0.3 to 3.2 +/- 0.5 cm/yr (p < 0.005) in the nine patients. Weight/height ratio decreased from 28.4% +/- 8.5% to 16% +/- 6.7% (p < 0.005). Cushingoid appearance decreased in all patients. Mean spontaneous growth hormone secretion increased from 2.5 +/- 0.4 to 4.4 +/- 1.2 ng/ml (p < 0.05). Our findings indicate that immunosuppressive treatment with deflazacort is as effective as methylprednisone and is associated with fewer side effects.

Body Height↗
PubMed1992

Isolated lung transplantation.

A clinical reality since 1981, lung transplantation is now generally accepted as a useful procedure for patients with end-stage lung disease. Early attempts at lung transplantation were marked by infection, rejection, and, in particular, bronchial dehiscence. Obliterative bronchiolitis, an airway-targeted form of chronic rejection, continues to be a problem. It is associated with all types of lung transplantation and is an important cause of late death. In the past few years advances in surgical technique, organ preservation and postoperative management have all contributed to improved survival and preservation of lung function. The shortage of suitable organ donors remains the limiting factor in clinical programs worldwide and curtails more widespread application of lung transplantation.

Humans↗
PubMed1991

Renal transplantation in patients with classical haemolytic-uraemic syndrome.

Eighteen records from children with renal transplants (RT) and classical haemolytic-uraemic syndrome (HUS) were reviewed. The mean oliguric period was 17.9 +/- 7.5 days; the interval between acute phase and end-stage renal disease (ESRD) was 9.3 +/- 5.2 years. HUS was the most frequent cause of renal transplantation (23.4%). There were no significant differences between patients with HUS and controls (children with RT but without HUS), regarding renal function, frequency of rejections, renal survival (HUS 65%, controls 57%) or patient survival (94.4% and 96.6%, respectively) after 9 years. None had clinical or histopathological evidence of HUS recurrence in the allograft. Of all children with living-related donors (LRD), renal survival after 3 years was longer for those who received cyclosporin A (CSA) (HUS and controls 86%) than for those who did not receive it (HUS 50%, controls 53%). Classical HUS is a frequent cause of ESRD in Argentina. The duration of the acute oliguric period is a good predictor of the likelihood of progression to chronicity. In the classical form of HUS there is no recurrence in the allograft. CSA and LRD can be used without risk in renal transplantation of children with classical HUS.

Child↗
PubMed1991

Evidence of hypothalamic-pituitary thyroid abnormalities in children with end-stage renal disease.

Patients with end-stage renal disease may have abnormalities of growth and of gonadal and thyroid hormones, so we attempted to determine the mechanisms that may be involved in the altered thyroid function. We evaluated serum thyroid hormone levels, their changes immediately after hemodialysis, the serum thyrotropin (thyroid-stimulating hormone (TSH) response to thyrotropin releasing hormone, and the circadian pattern of serum TSH in nine children with end-stage renal disease who were between 7 1/2 years and 17 years 1 month of age. Seven patients had been receiving hemodialysis for a median of 3.3 years; the other two were receiving continuous ambulatory peritoneal dialysis. Four patients had low serum total thyroxine (T4) values, and all nine had low free T4 values. Mean concentrations of total T4, free T4, and total triiodothyronine (T3), which were significantly less than normal before hemodialysis, returned to normal levels immediately after dialysis. Postdialysis thyroid hormone increases did not correlate with the decrease in weight or the increase in hematocrit observed immediately after dialysis. All but one patient had basal TSH levels within the normal range. Three patients had a deficient TSH response to thyrotropin releasing hormone, and the TSH response was prolonged in all of them. The mean (+/- SD) nocturnal TSH surge was 50 +/- 68%. Five of the eight patients studied had a nocturnal TSH surge below the normal range (95% confidence limits 47% to 300%). Serum free T4 values correlated with the TSH nocturnal surge (r, 0.73; p less than 0.05). Our findings support the hypothesis that some patients with end-stage renal disease have central hypothyroidism.

Adolescent↗
PubMed1991

Gas exchange during exercise in mild chronic obstructive pulmonary disease. Correlation with lung structure.

To investigate whether or not the pathologic features in the lungs of patients with chronic obstructive pulmonary disease (COPD) are related to the gas exchange response during exercise, we studied 17 patients (15 men, two women) with mild-to-moderate airflow obstruction (FEV1/FVC ratio, 59 +/- 3%), undergoing resective lung surgery, at rest and during submaximal exercise (71 +/- 5% predicted VO2max). During exercise, arterial PO2 increased (from 81 +/- 3 to 86 +/- 3 mm Hg, p less than 0.05) as a result of an overall improvement in VA/Q relationships. This improvement included an increase in the mean VA/Q ratios of both ventilation and blood flow distributions, and a more homogeneous ventilation distribution (logSD V, from 0.66 +/- 0.06 to 0.50 +/- 0.03; p less than 0.01; normal value, less than or equal to 0.6). The morphologic evaluation of the resected specimens disclosed a moderate degree of emphysema (emphysema score, 16 +/- 4) and mild abnormalities in membranous bronchioles (total pathology score, 107 +/- 8). At rest, significant correlations were found between the severity of the pathologic findings and both the degree of hypoxemia and the extent of VA/Q mismatching. During exercise, no relationship between bronchiolar abnormalities and gas exchange measurements was observed, whereas the severity of emphysema was correlated with PaO2 (r = -0.54, p less than 0.05). Both the overall increase in and the more efficient distribution of ventilation accounted for the improvement in VA/Q distributions during exercise. These changes were more pronounced in patients with a greater degree of bronchiolar abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Causes of the decrease in fluorescence due to proteolysis of alpha-casein.

Fluorescence decrease in casein solutions induced by proteolytic enzymes is mainly due to cleavage of alpha-casein, and in particular to alpha S1-casein, which is quantitatively the main component of commercial casein. Treatment of alpha-casein with o-iodosobenzoic acid, diminished its intrinsic fluorescence considerably and abolished the decrease in fluorescence induced by proteolytic cleavage. The carboxyterminal Trp at position 199 in alpha S1-casein contributes approximately 30% to the overall effect, while the Trp at position 164 contributes about 70%. Treatment of alpha-casein with cyanogen bromide lowered the initial fluorescence of the preparation, but, in the resulting fragment, trypsin still diminished some of the residual fluorescence. The velocity of decrease in fluorescence correlates with the distance from the Trp in position 164 at which the peptide bond is broken. This effect seems to be rather unique for the caseins, but particularly for alpha S1-casein; this is due to the existence of a Trp that is in the vicinity of hydrophobic amino acids and which upon hydrolysis, becomes exposed to a more hydrophilic environment.

Amino Acid Sequence↗
PubMed1990

Lung structure and gas exchange in mild chronic obstructive pulmonary disease.

To investigate the influence of pulmonary emphysema and small airways abnormalities on ventilation-perfusion (VA/Q) mismatching in mild chronic obstructive pulmonary disease (COPD), we studied 23 patients (mean predicted FEV1, 76 +/- 15%) before lung resection because of a localized neoplasm. Respiratory gas exchange and VA/Q distributions were measured while the patients breathed room air and 100% O2. Breathing room air, the AaPO2 was moderately increased (25 +/- 12 mm Hg) as was VA/Q mismatching, indicated by the dispersion (log SD) of both blood flow (Q) and ventilation (V) distributions (log SD Q, 0.78 +/- 0.3; and log SD V, 0.66 +/- 0.28, respectively) (normal range, 0.3-0.6). AaPO2, log SD Q, and log SD V all significantly correlated with the emphysema severity assessed morphologically from the resected lung specimens (r = 0.57, r = 0.62, and r = 0.45, respectively). Log SD V also significantly correlated with the severity of the inflammatory infiltrate of membranous bronchioles (r = 0.62). During 100% O2 breathing there was an increase in VA/Q mismatching (log SD Q rose to 1.12 +/- 0.08, p less than 0.001), suggesting release of hypoxic pulmonary vasoconstriction. This increase in VA/Q inequality was not significantly related to the severity of lung pathologic findings. We conclude that, in mild COPD, both pulmonary emphysema and small airways abnormalities contribute to VA/Q mismatch, the severity of emphysema being the major morphologic correlate of the increase in AaPO2.

Adult↗
PubMed1989

Leucine transport in plasma membrane vesicles of Saccharomyces cerevisiae.

Yeast plasma membrane vesicles were obtained by the fusion of liposomes with purified yeast membranes by means of the freeze thaw-sonication technique. Beef heart mitochondria cytochrome-c oxidase was incorporated into the vesicles. Addition of substrate (ascorbate/TMPD/cytochrome c) generated a membrane potential negative inside, and an alkaline pH gradient inside the vesicle, that served as the driving force for leucine transport. Both delta pH and delta psi could drive leucine transport. When delta pH was increased in the presence of valinomycin and potassium, at the expense of delta psi, leucine uptake increased by 10%.

Animals↗
PubMed1989

[Comparative study of Uromiron and 38% Lipiodol in sialography].

A comparative study was undertaken to assess the properties of uromiron and lipiodol 38%, which are used as radiopaque materials in sialographic techniques, on 25 young adult outpatients of both sexes that were seen at the Dental School, University of Chile, Santiago. It was found that, although the radiopaque properties of uromiron were less than lipiodol 38%, the can be improved by increasing the amount of material injected into the duct system of the salivary glands. Likewise, uromiron exhibited a proper biological tolerance and a rapid emptying time, therefore the use of uromiron in sialographic techniques seems to be a proper alternative to lipiodol 38%.

Adult↗
PubMed1989

[Hydrostatic sialography].

In the present paper we report our clinical experience with hydrostatic sialography, a modification of the conventional technique, which consist in introducing the contrast liquid into the salivary glands by means of gravity pressure. Additionally, a comparative study was done between both techniques. Our results are in accordance with those previously reported in the current literature i.e. the hydrostatic sialography is superior to the current technique, since does not allow the overinjection of the contrast liquid in the salivary gland and also is better tolerated by the patient. However, new experiences with the technique are needed, largely in patients with different diseases of the salivary glands in order to establish the usefulness of the latter in daily practice.

Adult↗
PubMed1988

Esophagectomy for complex benign esophageal disease.

We evaluated the use of total thoracic esophagectomy and replacement with stomach in a group of 21 patients between 1976 and 1986 who had undergone multiple unsuccessful esophageal operations. All patients had between one and four unsuccessful operations for benign esophageal disorders. Sixteen patients had primary motor disorders: achalasia in nine and esophageal spasm in seven. Of these patients, 11 also had recurrent gastroesophageal reflux and peptic esophagitis. Complicated reflux disease characterized by severe esophagitis, stricture, and impaired peristalsis without primary motor disorder occurred in five patients. In one patient a functionally impaired long-segment colon interposition was removed and replaced with stomach. Total thoracic esophagectomy and cervical esophagogastric reconstruction was done in all patients. The transhiatal approach was chosen for resection in 16 patients and thoracotomy was used in the other five. There was one perioperative death (5%), from massive aspiration 4 days after transhiatal esophagectomy. Other complications included transient anastomotic leak (three patients), tracheoesophageal fistula (one), recurrent nerve palsy (one), and transient hoarseness (two). Follow-up is complete between 1 and 10 years and reveals the following functional results: 12 patients good to excellent, seven fair, one poor. In this patient group in which multiple prior procedures have failed to improve severe incapacitating symptoms, we believe further attempts at hiatal reconstruction are unlikely to succeed. For this circumstance, we recommend total thoracic esophagectomy with the use of stomach as the replacement organ of choice.

Adult↗
PubMed1988

Radiographic bilateral cavitary lesions in lipoid pneumonia.

We report a case of lipoid pneumonia with pulmonary bilateral cavitated lesions. The diagnosis was based on the finding of abundant lipid-laden alveolar macrophages in bronchoalveolar lavage and the presence of histologic changes indicative of lipoid pneumonia in transbronchial lung biopsy.

Adult↗