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Biomedical subjects

M Castro

Publications and source records attributed to M Castro.

At least 199 records · Page 11Linked to original sources
PubMed1993

Longitudinal evaluation of adrenocorticotrophin and beta-lipotrophin plasma levels following bilateral adrenalectomy in patients with Cushing's disease.

OBJECTIVES: Bilateral adrenalectomy may be indicated in patients with Cushing's disease in whom hypercortisolism is not resolved after pituitary microsurgery. However, Nelson's syndrome is a major long-term complication of such therapy. We have carried out a longitudinal study on patients with Cushing's disease who underwent bilateral adrenalectomy comparing plasma beta-lipotrophin (beta-LPH) with ACTH levels. PATIENTS AND METHODS: Seven patients unsuccessfully treated by pituitary surgery for Cushing's disease underwent bilateral adrenalectomy. Blood samples were collected on days 8 and 15 and at 1, 2, 3, 6, 9, 12, 18 and 24 months after adrenalectomy in all patients. Five patients were followed up for the longer periods of 30, 33, 39, 72 and 84 months respectively. Plasma ACTH and beta-LPH were determined by RIA after extraction. Pituitary CT scan was done at 6-8 month intervals. RESULTS: A pituitary tumour was detected in three patients at 14, 24 and 26 months after adrenalectomy respectively. The basal ACTH (range 8-21 pmol/l) began to rise between 15 and 30 days and exhibited a sharp increase with a range of 36-114 pmol/l at 3 months and a range of 53-187 pmol/l at 6-9 months after adrenalectomy. The ACTH levels in the three patients who later presented with a pituitary tumour were indistinguishable from those observed in the other patients up to 12 months after adrenalectomy. Only at 12 months or thereafter were their ACTH levels higher than in the other patients (958 +/- 252 vs 205 +/- 22 pmol/l). beta-LPH concentrations changed in parallel with ACTH levels. The ACTH levels correlated positively with beta-LPH levels (r = 0.76). CONCLUSIONS: In patients with Cushing's disease undergoing bilateral adrenalectomy, plasma ACTH and beta-LPH concentrations cannot predict the development of pituitary tumours until 12 months after surgery.

Adolescent↗
PubMed1993

Vitronectin binds to Pneumocystis carinii and mediates organism attachment to cultured lung epithelial cells.

Pneumocystis carinii attaches to alveolar epithelial cells during the development of pneumonia. Adhesive proteins found within the alveolar space have been proposed to mediate P. carinii adherence to lung cells. Vitronectin (Vn), a 75-kDa glycoprotein present in the lower respiratory tract, has substantial cell-adhesive properties and might participate in the host-parasite interaction during P. carinii pneumonia. To address whether Vn binds to P. carinii, we studied the interaction of radiolabeled Vn with purified P. carinii organisms. Vn bound to P. carinii, occupying an estimated 5.47 x 10(5) binding sites per organism, with an affinity constant, Kd, of 4.24 x 10(-7) M. Interestingly, the interaction of Vn with P. carinii was not mediated through the Arg-Gly-Asp cell-adhesive domain of Vn. Addition of Arg-Gly-Asp-Ser (RGDS) peptides did not inhibit binding. In contrast, Vn binding to P. carinii was substantially inhibited by the addition of heparin or by digesting the organisms with heparitinase, suggesting that P. carinii may interact with the glycosaminoglycan-binding domain of Vn. To determine whether Vn might enhance P. carinii attachment to lung epithelial cells, we studied the binding of 51Cr-labeled P. carinii to cultured A549 lung cells. Addition of Vn resulted in significantly increased binding of P. carinii to A549 cells, whereas a neutralizing anti-Vn serum substantially reduced the binding of P. carinii to A549 cells. These data suggest that Vn binds to P. carinii and that Vn might provide an additional means by which P. carinii attaches to respiratory epithelial cells.

Amino Acid Sequence↗
PubMed1993

Linear growth in thalassemic children treated with intensive chelation therapy. A longitudinal study.

The aim of our study was to investigate the effect of a definite schedule of treatment on the growth of children with beta-thalassemia major. Ten children (6 girls, 4 boys) participated in this longitudinal study. They were treated with transfusions to maintain the levels of hemoglobin above 10.5 g/dl from the time of diagnosis and desferrioxamine mesylate 40 mg/kg/day by subcutaneous pump, 5 days a week, during 7 +/- 1.4 years. The patients were followed up from the age at diagnosis (18.9 +/- 9.8 months) until they reached their adult bone age (19.1 +/- 1.6 and 20.8 +/- 0.8 years in girls and boys, respectively). We observed growth retardation before the age of 10 in 3 out of 4 boys and in 1 out of 6 girls. Between the ages of 10 and 15, the growth failure was evident in other children (1 boy and 2 girls), and became more marked in the above mentioned children. After the age of 15, amelioration of the growth failure was observed in relation to sexual maturity. Eight out of 10 patients attain normal stature in accordance with their target height. We had evidence of poor compliance with the chelation therapy in the 2 children of short adult stature. These patients had higher serum ferritin levels than the children with normal height within the study period: 4,461 +/- 1,469 and 1,429 +/- 479 micrograms/l respectively (p = 0.049). Our study reveals a positive effect of intensive chelation therapy on the linear growth in these patients.

Blood Transfusion↗
PubMed1993

Pneumocystis carinii induces the release of arachidonic acid and its metabolites from alveolar macrophages.

Pneumocystis carinii is an opportunistic organism that causes severe lung injury in immunocompromised hosts. Macrophage responses to P. carinii are poorly defined. Arachidonic acid (AA) and its metabolites are potent mediators of inflammation and have been implicated in host response to microorganisms. We therefore examined the production of eicosanoids from rat and rabbit alveolar macrophages stimulated with purified P. carinii. [14C]AA-labeled rabbit macrophages released 8.50 +/- 1.33% of the incorporated [14C]AA after 90 min in response to P. carinii (P = 0.0001 compared with unstimulated controls). In contrast, a similar number of rat alveolar macrophages exhibited a smaller but significant response to P. carinii, releasing 3.84 +/- 1.54% of their [14C]AA after 90 min (P = 0.001 compared with control). We further determined that P. carinii stimulated substantial production of prostaglandin E2 and concurrently a small amount of leukotriene B4 release from alveolar macrophages. To further investigate whether serum opsonization of P. carinii enhances these alterations in AA metabolism, we assessed the effect of P. carinii immune serum on P. carinii-induced AA release. P. carinii opsonized with this antiserum caused significantly greater AA release from rat alveolar macrophages than either unopsonized P. carinii or organisms opsonized with nonimmune serum. Previous studies suggest that P. carinii interacts with macrophage beta-glucan and mannose receptors. However, incubation of macrophages with P. carinii in the presence of either soluble beta-glucan or alpha-mannan failed to alter the release of AA from macrophages in response to P. carinii. Macrophage release of eicosanoids represents a potentially important host inflammatory response to P. carinii infection.

Animals↗
PubMed1993

Effect of air-supported, continuous, postural oscillation on the risk of early ICU pneumonia in nontraumatic critical illness.

STUDY OBJECTIVES: We hypothesized that continuous, automatic turning utilizing a patient-friendly, low air loss surface would reduce the incidence of early ICU pneumonia in selected groups of critically ill medical patients. DESIGN: Prospective, randomized, controlled clinical trial. SETTING: Medical ICU of a large community teaching hospital. PATIENTS: One hundred twenty-four critically ill new admissions to the medical ICU at Charity Hospital in New Orleans. INTERVENTIONS: Patients were prospectively randomized within one of five diagnosis-related groups (DRG)--sepsis (SEPSIS), obstructive airways disease (OAD), metabolic coma, drug overdose, and stroke--to either routine turning on a standard ICU bed or to continuous turning on an oscillating air-flotation bed for a total of five days. MEASUREMENTS AND RESULTS: Patients were monitored daily during the treatment period for the development of pneumonia. The incidence of pneumonia during the first five ICU days was 22 percent in patients randomized to the standard ICU bed vs 9 percent for the oscillating bed (p = 0.05). This treatment effect was greatest in the SEPSIS DRG (23 percent vs 3 percent, p = 0.04). Continuous automatic oscillation did not significantly change the number of days of required mechanical ventilation, ICU stay, hospital stay, or hospital mortality overall or within any of the DRGs. CONCLUSIONS: We conclude that air-supported automated turning during the first five ICU days reduces the incidence of early ICU pneumonia in selected DRGs; however, this form of automated turning does not reduce other measured clinical outcome parameters.

Beds↗
PubMed1993

[Food intolerance and irritable bowel syndrome of childhood: clinical efficacy of oral sodium cromoglycate and elimination diet].

Irritable bowel syndrome (IBS) is recognized to be a common cause of chronic diarrhea without failure to thrive in childhood. Several studies stressed the role of food intolerance as a major factor in the pathogenesis of IBS. The aim of this multicenter study was to investigate the offending role of food in IBS and to compare the therapeutic role of oral sodium cromoglycate versus elimination diet. 153 patients (mean age 4 years) with diarrhea (> 3 stools per day for four days in a week) and abdominal pain for about 10 months were enrolled in this trial. About half of the patients had a family history positive for atopy and 70% of the cases complained of intestinal symptoms after food ingestion. In 17% of the patients Skin Prick test (SPT) resulted positive to at least one food allergen and 87% of positive reactions to SPT was provoked by common foodstuffs. 87% of patients treated with elimination diet (rice, lamb, turkey, lettuce, carrots, sweet potatoes, pears, oil, tea, salt, mineral water, brown sugar) and 97% of patients treated with SCG (mean 63 mg/kg/day) for one month showed a significant improvement of intestinal symptoms. An elimination diet for several weeks can produce, beside a bad compliance (23% of patients admitted to our study didn't strictly follow diet regimen) also a nutritional deprivation. The results of this trial suggest that it's correct to investigate the role of food in children with diarrhea not due to organic diseases and diagnosed such as IBS and to use oral SCG to obtain the improvement of these symptoms.

Adolescent↗
PubMed1993

[Primary cardiac hemangioma. A case report and review of the literature].

A 26-years-old woman, without symptoms, was diagnosed of cardiac tumor by means of two-dimensional echocardiography, magnetic resonance imaging and angiocardiography. The tumor was removed underwent open-heart operation and cardiopulmonary bypass. Histologic study was suggestive of a capillary hemangioma. We present our experience with this case and a review of the literature.

Adult↗
PubMed1993

Comparison of maternal sera, cord blood, and neonatal sera for detecting presumptive congenital syphilis: relationship with maternal treatment.

The incidence of congenital syphilis has increased rapidly over the past few years. Most infected mothers and their newborns are asymptomatic at birth and diagnosis depends on serologic testing during pregnancy and at delivery. This study was initiated to compare maternal sera, cord blood, and neonatal sera for detecting presumptive congenital syphilis and to assess the role of maternal treatment (administration of penicillin to the mother at least 1 month before delivery) on the serologic results at the time of delivery. The serologic results from all live deliveries complicated by a positive maternal and/or neonatal test for syphilis during a 12-month period were compared using chi 2 analysis and multiple comparisons for proportions. Of 3306 livebirths, 73 (2.2%) were complicated by a positive maternal or neonatal serology. At delivery, the serologic test was positive in 68 (94%) of 72 maternal sera, 30 (50%) of 60 cord sera, and 43 (63%) of 68 neonatal sera. In the absence of maternal treatment, 95% of the maternal sera, 66% of the cord blood samples, and 86% of the neonatal sera were positive. If the mother had been treated, 94% of maternal sera, 36% of cord sera, and 39% of neonatal sera were positive. Cord blood and neonatal sera appear to be inferior to maternal sera for detecting prenatal exposure to syphilis. Cord serology is also inferior to neonatal serology at 2 to 3 days of age. The most effective way to identify newborns at risk for congenital syphilis is to obtain a maternal serologic diagnosis during pregnancy and to test maternal and neonatal sera at delivery.

Age Factors↗
PubMed1993

Down's syndrome and celiac disease: the prevalence of high IgA-antigliadin antibodies and HLA-DR and DQ antigens in trisomy 21.

Patients with Down's syndrome (DS) or celiac disease (CD) have altered immune systems. Autoimmune diseases have been described in both conditions; the coexistence of DS and CD has been occasionally reported, but a clear relationship has not been definitely established. In this study we determined IgA antigliadin antibodies (IgA-AGA) in 155 children with DS, and the results were compared with those of the control groups formed by 320 children affected by upper-respiratory tract infections and 115 children with gastrointestinal symptoms but with normal jejunal mucosa. High IgA-AGA levels were found in 26% of DS patients, in 1% of the first control group and in 10% of the second control group. Such differences are statistically significant. Twenty-one DS patients with high IgA-AGA levels and gastrointestinal symptoms underwent jejunal biopsy, and total villous atrophy was found in seven of them (33.33%). HLA-DR and -DQ antigens were also determined in 75 DS patients (20 with high and 55 with normal IgA-AGA levels), and the percentages of the different phenotypes were compared in the two groups and with those of a control group. No statistically significant difference was found, but DR3, DR7, and DQ2 alleles were always present in DS patients with jejunal atrophy. Our study confirms the data reported in the literature about higher levels of IgA-AGA in DS patients and the relatively high incidence of CD in this group of patients.

Adolescent↗
PubMed1992

Effect of a restricted diet on the in vitro glucose-induced insulin release of aging rats.

To study the effect of a sudden loss of body weight on the beta-cell function of aging rats, basal and glucose-induced insulin secretion was measured in pancreatic islets obtained from young (2-month-old), adult (12-month-old) and aging (24-month-old) rats, either fed ad libitum or fed a restricted diet (50% caloric restriction). Basal insulin secretion was similar in islets of young, adult and older rats. Glucose stimulated insulin release was significantly reduced in aging rats as compared to young animals. Animals fed a restricted diet showed a prolonged and higher secretory rate during first phase release when compared to animals fed ad libitum.

Aging↗
PubMed1992

Epidemiology of taeniasis and cysticercosis in a Peruvian village. The Cysticercosis Working Group in Peru.

To determine the prevalence of cysticercosis in a rural area where the disease is endemic, the authors studied the seroepidemiology of human and porcine cysticercosis in a Peruvian jungle community (Maceda, Peru) in 1988 using an enzyme-linked immunoelectrotransfer blot (EITB) assay. Of the 371 sampled inhabitants, 30 (8%) were seropositive, most of whom were asymptomatic. After niclosamide therapy, four Taenia species worms were identified in the seropositive group, compared with one in the control group (p = 0.06). Pigs were frequently infected: 44 of 133 (33%) were found positive for Taenia by tongue examination and 57 of 133 (43%) were positive by EITB. In 69% of the sampled households that had pigs, there was at least one seropositive pig. The number of pigs diagnosed positive by the tongue examination was significantly greater in households that had latrines than in those that did not. Cysticercosis is a common but usually asymptomatic infection that affects both humans and pigs in the high jungle areas of Peru.

Adolescent↗
PubMed1992

Effect of DL-propranolol on nitric oxide production in perfused rat hindquarters.

The effect of DL-propranolol on NO release in perfused rat hindquarters was studied by using oxyhemoglobin as a capture system to allow the quantitative assay of NO production. In some experiments the stable prostacyclin metabolite 6-keto-PGF1 alpha (6-keto) was simultaneously assayed. We observed that: (1) DL-propranolol induced an increase in NO and 6-keto release. The dextro isomer was inactive; (2) DL-propranolol-induced NO release was only slightly reduced by acetylsalicylic acid in a concentration that inhibits prostacyclin synthesis, and was abolished by the chemical removal of the endothelium with 3-3 cholamidopropyl dimethylammonium 1-propane sulphonate (CHAPS) applied before or during stimulation; (3) NG-nitro-L-arginine blocked DL-propranolol-induced NO production, an effect that was antagonized by L-arginine but not by its dextro isomer.

6-Ketoprostaglandin F1 alpha↗
PubMed1992

Acquisition of responsiveness to chemical carcinogens by rodent embryo fibroblasts expressing high levels of the c-myc proto-oncogene.

We investigated the ability of overexpression of the c-myc proto-oncogene to potentiate in vitro transformation by model chemical carcinogens. A mouse c-myc gene was introduced to C3H 10T1/2 and Rat 6 embryo fibroblast cell lines via a retroviral vector containing the gene for neomycin resistance. Our present work extends previous findings by showing that individual vectored C3H 10T1/2 clones have enhanced (two-fold to sevenfold) sensitivity to benzo[a]pyrene (BP) and N-methyl-N-nitro-N'-nitrosoguanidine (MNNG). Rat 6 clones acquiring the c-myc gene display various degrees of altered morphology. They form orderly but densely packed cells, grow to higher saturation density, and yield microcolonies in soft agar. The degree of altered growth properties is directly correlated with the level of c-myc expression. Transient exposure of c-myc-expressing clones to BP and MNNG induced the formation of distinct, large colonies in soft agar, whereas the untreated cells formed microcolonies and the parental Rat 6 cells remained single cells in soft agar. We also demonstrated that the degree of responsiveness to chemical carcinogens of the clones correlates with their ability to form microcolonies in soft agar. These cells overexpressing c-myc may be used as a model system to study the interaction between oncogenes and chemical carcinogens in the process of multistage carcinogenesis.

Animals↗
PubMed1992

Simultaneous reconstruction of infrarenal abdominal aorta and renal arteries.

From 1980 to 1990, 48 (4.7%) of 1,002 patients underwent elective aortic reconstruction and simultaneous renal artery reconstruction. Forty-five men and three women (mean age: 66.5 years) had 59 renal artery lesions (51 stenoses, six occlusions, one dysplasia, and one aneurysm) associated with 20 infrarenal aortic aneurysms and 28 aortoiliac occlusive lesions. One nephrectomy and 58 renal artery reconstructions were performed (35 prosthetic bypasses, 11 vein bypasses, six direct reimplantations, five transaortic endarterectomies, and one resection of an intrahilar aneurysm followed by autotransplantation). Operation was always indicated for the aortic lesions. Indication for renal artery repair was hypertension in 33 cases (17 associated with renal insufficiency) and one with isolated renal insufficiency. In the remaining 14 cases, surgery was deemed preventive. One patient died (2%). There were 12 nonfatal complications two of which were kidney failures requiring chronic extrarenal epuration. Routine follow-up arteriograms showed four postoperative renal artery occlusions. Mean follow-up was 35.8 months. Four patients were lost to follow-up; 10 died secondarily. Five year survival was 72.1 +/- 19.1%. Secondary patency of renal artery reconstruction was 89.5 +/- 9.4% at five years. Late results were favorable in 45% of patients with hypertension and in 39% of patients with renal insufficiency. Mortality in simultaneous aortic and renal artery reconstruction is not superior to that of isolated infrarenal aortic surgery.

Actuarial Analysis↗
PubMed1992

Adrenocorticotropin-corticosterone relationship during dexamethasone therapy in 17 alpha-hydroxylase deficiency.

A previous study in an untreated girl with 17 alpha-hydroxylase deficiency syndrome (17-OHDS) indicated that in the absence of cortisol production, ACTH and corticosterone (B) may interact to modulate the brain-pituitary-adrenocortical system. The ACTH-B interplay was further examined in this patient under dexamethasone therapy and after withdrawal of treatment. Plasma ACTH and B were highly correlated (r = 0.89) during two different schedules of dexamethasone treatment and two weeks off treatment at all blood sampling times (morning, afternoon or 24-h period). A logarithmic-sigmoidal relationship seems to exist between ACTH and B secretion. The time course of ACTH-B relationship early after withdrawal of therapy showed good parallelism between these two variables. Plasma B may be a useful guide for monitoring therapy in 17-OHDS. The present study also indicates the ACTH-B interplay feedback set-points.

Adolescent↗
PubMed1992

Adrenocortical dysfunction in paracoccidioidomycosis: comparison between plasma beta-lipotrophin/adrenocorticotrophin levels and adrenocortical tests.

OBJECTIVE: Paracoccidioidomycosis is an important cause of Addison's disease in South America. We have carried out an extensive and prospective study on paracoccidioidomycosis comparing glucocorticoid, mineralocorticoid and androgen function with adrenal regulators, ACTH/beta-LPH and plasma renin activity (PRA). PATIENTS AND METHODS: Forty-seven male patients with active paracoccidioidomycosis were studied consecutively together with 20 healthy controls. On day 1, plasma aldosterone and PRA levels were measured in blood samples obtained from patients in the supine and erect position. On day 2 at 0900 h, baseline plasma samples were taken for ACTH, beta-lipotrophin (beta-LPH), cortisol, corticosterone, aldosterone, androstenedione (delta 4-A) and dehydroepiandrosterone sulphate (DHEA-S). ACTH 1-24 (250 micrograms) was given i.v. and blood samples for these steroid assays were taken at 1 and 2 hours. RESULTS: Five patients (10%) had Addison's disease with high basal plasma ACTH and beta-LPH, and low cortisol levels after the ACTH test. In the remaining 42 patients, baseline ACTH and beta-LPH levels and plasma cortisol after ACTH were within the normal range. A high percentage of patients presented with reduced corticosterone (21% of patients) and aldosterone (23%) secretion and increased PRA (31%). Plasma delta 4-A (19%) and DHEA-S (50%) levels were also reduced. CONCLUSIONS: The frequency of Addison's disease among our patients with paracoccidioidomycosis was 10%. In addition, a subset of patients presented with adrenal dysfunction detected by mineralocorticoid or androgen tests. In parallel to pathological lesions a functional adaptation may occur during adrenal involvement in paracoccidioidomycosis.

Addison Disease↗
PubMed1992

Luteinizing hormone response to clomiphene citrate in central precocious puberty.

OBJECTIVE: The aim of the present study was to determine the LH response to clomiphene citrate administration in children with central precocious puberty and different bone ages to gain insight into the hypothalamic maturation mechanism. PATIENTS AND METHODS: Twelve children with untreated central precocious puberty were studied. Five had central nervous system lesions and seven had idiopathic central precocious puberty. Their chronological and bone ages ranged from 1.7 to 8.8 years and 3.5 to 13.5 years, respectively. Clomiphene citrate (3 mg/kg/day) was administered orally for 7 days. Blood samples were collected on days 0, 6 and 8. LH and FSH were determined by RIA. The results were compared with GnRH responses or with bone age. RESULTS: No increase over basal LH levels was detected in four patients, but increased LH levels were detected in the remaining eight during clomiphene administration. The shift from negative to positive responses was around 8-9 years bone age. The sum of LH responses (days 6 and 8) to clomiphene citrate, and particularly the 8th-day LH levels, were significantly correlated with their respective bone age (r = 0.83). However, the LH responses to GnRH were not significantly correlated with bone age or with LH responses to clomiphene. CONCLUSIONS: This study shows that the LH responsiveness to clomiphene citrate in central precocious puberty increases with skeletal maturation, indicating that the activation of the hypothalamic pubertal mechanism in central precocious puberty may progress in a gradual sequence. These changes in LH response to clomiphene in central precocious puberty mimic those observed with the development of normal puberty, but occur at a much earlier age.

Bone Development↗