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Biomedical subjects

P Contreras

Publications and source records attributed to P Contreras.

At least 19 recordsLinked to original sources
PubMed2006

[Solid renal mass up to 4 cm. Analysis of the diagnostic procedures, TNM staging and surgical treatment].

OBJECTIVES: We perform a retrospective review of renal tumors operated with a maximum size of 4 cm to determine if the diagnostic methodology was adequate, the TMN staging prognostic accuracy (UICC 2002) and the goal surgical treatment. MATERIAL AND METHOD: Between 1984 to 2005, 78 renal units form 74 patients (4 bilateral synchronous) operated at the Service of Urology of the Hospital Alemán de Buenos Aires. Age distribution, sex, presentation form (incidental and symptomatic), diagnostic methodology, laboratory variables, surgical treatment (partial or radical surgery), histopathology, Fuhrman grade, tumor size, bilaterality, multicentricity, TNM staging, evolution and survival (Kaplan Meier) were analyzed. RESULTS: 78 renal units from a total of 192, 40.62% were analyzed. The median age was 58.72 years. 69% were male and 31% female. The presentation form was 91.90 % incidental and symptomatic 8.10% (Hematuria in 5 and lung metastasis in 1). The diagnosis was performing with ultrasound and CT scan 63 cases, in 4 was also used resonance magnetic imaging (RMI) and in 7 ultrasound and RMI. Arteriography was used in 11 cases, 3 showed tumor and 8 were normal. Biopsy was performing in 5 cases, all positive for clear cells carcinoma. Globular sedimentation was the only one laboratory abnormality in 12 cases. Surgical treatment was radical surgery in 35 renal units (44.87%) and conservative surgery in 43 units (55.13%). Pathology clear cells carcinoma (CCC) 79.48%, papillary carcinoma 1.28%, angiomyolipoma (AML) 8.97%, oncocytoma 7.69% and adenoma 2.56%. The Fuhrman grade was 1 in 76.19%; 2 in 20.63% and 3 in 3.18%. Bilateral tumor were found in 4 cases 2 CCC, 1 CCC and AML and 1 CCC and adenoma. Tumor median size was 2.93 cm. Staging was T1a 96.82%, T3a 1.59% and T3aM+ 1.59%. Follow-up could be made in 54 of 61 cases. At median follow-up of 52.25 months, 50 cases were disease free, 3 died by progression at 18, 33 and 82 months and all of them were symptomatic tumors, 1 died by a non related cause. Survival rate was 94%. CONCLUSIONS: 1)Ultrasound and CT scan obtained a highest diagnostic accuracy for solid renal mass. Biopsy in selective cases could contribute to achieve a correct treatment strategy. 2) Conservative surgery was the goal treatment in selected tumors up to 4 cm. and we believe that TNM staging should contemplate the presentation form to improve the prognostic value.

Adult↗
PubMed2002

A comparison between an in vitro method to determine carbohydrate digestion rate and the glycemic response in young men.

OBJECTIVE: This study examines the relationship between the results of in vitro determinations of carbohydrate digestion rates and the glycemic index. SUBJECTS: Ten healthy non smoking men, aged between 21 and 24-y-old, were selected to participate in the study. METHODS: Six different meals with similar levels of carbohydrates were assayed at breakfast in ten subjects and blood samples were obtained at 0, 15, 30, 60 and 120 min to determine glucose levels. The Englyst's enzymatic method was used in the in vitro study. The six meals were based in cereals (rice or spaghetti); legumes (lentil soup and beans with spaghetti); and potato (potato stew with meat and vegetables). RESULTS: The meals showed different glycemic indices: rice and spaghetti based meals had lower values (mean value 31.4 and 42, respectively); the intermediate values corresponded to lentil soup and the bean dish (49.3, and 76.8 respectively) and the higher glycemic index was shown by the potato based meal (82). CONCLUSIONS: A significant correlation was observed when the ratio of rapid carbohydrate digestion rate and the lente carbohydrate digestion rate was correlated with the glycemic index of the meals, but not when only the rapid carbohydrate digestion rate was considered. These results demonstrate a useful, simple and inexpensive method to estimate the biological response of high carbohydrate meals.

Adult↗
PubMed2001

Catecholamine levels in practitioners of the transcendental meditation technique.

With the aim of evaluating the sympathetic-adrenal medulla system in subjects practicing transcendental meditation (TM), their plasma catecholamine levels were determined at two different times of day. The study group consisted of 19 subjects who regularly practice either TM or Sidhi-TM technique, with a control group made up of 16 healthy subjects who had not previously used any relaxation technique. Catecholamine plasma levels were determined by high performance liquid chromatography, at 0900 and 2000 h. Morning and evening norepinephrine (NE) levels and morning epinephrine (E) levels were significantly lower in the TM group than in the control subjects (morning NE levels, pg/ml, mean+/-S.E.: TM group 136.6+/-13.0, control 236.8+/-21.0, P=.0001; evening NE levels: TM group 119.7+/-10.8, control 175.6+/-17.4, P=.009; morning E levels, pg/ml: TM group 140.2+/-10.6, control 196.7+/-23.8, P=.019). No differences were recorded for evening E levels and dopamine (DA) levels. No significant differences were found for catecholamine levels measured at different times of day in the TM group, demonstrating a lack of daily hormonal rhythm. Anxiety levels were similar in both groups. Based on the results obtained, it can be considered that the regular practice of TM has a significant effect on the sympathetic-adrenal medulla system. A low hormonal response to daily stress caused by sympathetic tone regulation through regular TM could explain our results, as well as the physiological and other effects related to the field of health described in those who practice meditation.

Adolescent↗
PubMed2001

Relative influence of age, resting heart rate and sedentary life style in short-term analysis of heart rate variability.

In order to assess the relative influence of age, resting heart rate (HR) and sedentary life style, heart rate variability (HRV) was studied in two different groups. The young group (YG) consisted of 9 sedentary subjects aged 15 to 20 years (YG-S) and of 9 nonsedentary volunteers (YG-NS) also aged 15 to 20. The elderly sedentary group (ESG) consisted of 16 sedentary subjects aged 39 to 82 years. HRV was assessed using a short-term procedure (5 min). R-R variability was calculated in the time-domain by means of the root mean square successive differences. Frequency-domain HRV was evaluated by power spectrum analysis considering high frequency and low frequency bands. In the YG the effort tolerance was ranked in a bicycle stress test. HR was similar for both groups while ESG showed a reduced HRV compared with YG. Within each group, HRV displayed a negative correlation with HR. Although YG-NS had better effort tolerance than YG-S, their HR and HRV were not significantly different. We conclude that HRV is reduced with increasing HR or age, regardless of life style. The results obtained in our short-term study agree with others of longer duration by showing that age and HR are the main determinants of HRV. Our results do not support the idea that changes in HRV are related to regular physical activity.

Adolescent↗
PubMed2000

[Scintigraphic pattern in a case of Tarlov cyst].

We report the case of a 40-year-old man remitted to our department with a history of lower back pain and sciatica with no history of trauma. The laboratory analyses showed normal values whereas plain radiographs showed a sacrum rarefaction area. A 99mTc-MDP bone scintigraphy was performed to evaluate the lumbosacral area. Planar images did not show any abnormality. SPECT images revealed photopenic abnormality in the second sacral vertebral right hemibody, with no peripherally increased radiotracer accumulation. Subsequent MRI and CT myelography demonstrated the nature of the photopenic area as secondary to vertebral erosion by sacral perineurial cyst (Tarlov cyst).

Adult↗
PubMed2000

Comparative study between children with and without cleft lip and cleft palate, part 1: cephalometric analysis.

OBJECTIVE: This study was conducted to compare craniofacial relationships, position, and curvature of the cervical spine between children with cleft lip and cleft palate who had been operated on and children without clefts. METHOD: This study was performed in 28 children with mixed dentition. They were divided into two groups. The study group included 14 children with unilateral operated cleft lip and cleft palate, ranging in age from 6 to 12 years, who clinically presented with a short upper lip, abnormal lip seal, and inhibition of sagittal development of the midface that was radiographically assessed. The control group included 14 children without clefts, ranging in age from 8 to 11 years. All of them had normal lip seal, nasal breathing, and a clinically normal body posture. DESIGN: A lateral craniocervical radiograph in a self-balanced natural head position in an erect posture, and without using a head holder, was taken for each child of both groups, with the mandible in maximum intercuspation and lips in habitual posture. The true vertical was marked on all the films. Specific angular and linear dimensions were used to assess the craniocervical relationships, as were the position of the cervical spine, its curvature, or both. RESULTS AND CONCLUSIONS: The study group presented a significant increase in the extension of the head on the neck, forward position of the cervical spine, and a decrease in the curvature of the cervical spine in comparison with the children without clefts. These results are more relevant considering that the study group also presented higher significant values of lower facial height than children without clefts.

Cephalometry↗
PubMed1999

Acute gastrointestinal effects of graded levels of copper in drinking water.

The objective of this study was to determine the acute gastrointestinal effects caused by the consumption of drinking water containing graded levels of added copper. Sixty healthy, adult women were randomly assigned to receive copper [Cu(II)] at four concentrations in their drinking water following a Latin-square design. Each group (n = 15) received tap water with no added copper, 1, 3, and 5 mg Cu/l of added copper sulfate for a 2-week study period, followed by 1 week of standard tap water. The subjects recorded their water consumption and gastrointestinal symptoms daily on a special form. The average daily consumption of water was 1.64 liters per subject, regardless of the amount of copper added. Final serum copper, ceruloplasmin, and liver enzymes were measured in all subjects and were not different from baseline concentrations. Twenty-one subjects (35%) recorded gastrointestinal disturbances sometime during the study, 9 had diarrhea, some with abdominal pain and vomiting, and 12 subjects presented abdominal pain, nausea, or vomiting. There was no association between copper levels in drinking water and diarrhea. However, nausea, abdominal pain, or vomiting were significantly related to copper concentrations in water. The recorded incidence rate of these symptoms was 5, 2, 17, and 15% while ingesting water with 0, 1, 3, and 5 mg Cu/l, respectively (overall [chi]2 = 11.3, p<0.01; Cu [less than/equal to]1 mg/l versus Cu [Greater than/equal to]3 mg/l, [chi]2, p<0.01). When subjects interrupted their consumption of drinking water with added copper, most symptoms disappeared. We conclude that under the conditions of the study, there was no association between aggregate copper in drinking water within the range of 0-5 mg/l and diarrhea, but a [Greater than/equal to]3 mg Cu/l level of ionized copper was associated with nausea, abdominal pain, or vomiting. Additional studies with sufficient numbers of subjects are needed to define thresholds for specific gastrointestinal symptoms with precision and to extrapolate these results to the population at large.

Adult↗
PubMed1999

[CEA, CA 19.9 and CA 195 in patients with colorectal carcinoma. ROC analysis].

The aim of this study was to assess the utility of determining serum levels of the CEA, CA 19.9 and CA 195 tumor markers in 906 patients with colorectal carcinoma for a 5-year follow-up period. In addition to calculating sensitivity and specificity for the common normal limits, the results were analyzed with RO curves. Sensitivity values for 90% and 95% specificity were also obtained. The results of the areas under the curve (CEA: 0.887; CA 19.9: 0.802; CA 195: 0.971) and sensitivities and specificities at different normality limits showed better behavior for CEA with respect to CA 19.9 and CA 195, the last two presenting similar results. CEA continues to be the best tumor marker to monitor patients with colorectal carcinoma.

Adenocarcinoma↗
PubMed1997

Immunological markers of disease progression in patients infected with the human immunodeficiency virus.

Identification of inexpensive and technically simple immunological tests useful in predicting the progression to AIDS in human immunodeficiency virus (HIV)-infected patients would be especially welcome in developing countries, in which 80% of HIV-infected patients reside and health budgets are low. In the current study, we evaluated CD4+ and total lymphocyte counts and the concentrations in serum of beta 2-microglobulin, p24 antigen, and immunoglobulin A (IgA) as predictors of disease progression in 74 Panamanian HIV-positive patients and 50 HIV-negative healthy individuals. Total lymphocyte and CD4(+)-cell counts for AIDS patients (1,451 +/- 811 cells/microliters, P < 0.001, and 238 +/- 392 cells/microliters, P < 0.0001, respectively and asymptomatic patients (2,393 +/- 664 cells/microliters, P > 0.05, and 784 +/- 475 cells/microliters, P < 0.001, respectively) were lower than those observed for healthy subjects (2,596 +/- 631 cells/microliters and 1,120 +/- 296 cells/microliters, respectively). The levels of beta 2-microglobulin and IgA in serum were significantly elevated in patients with AIDS (5.7 +/- 3.6mg/liter, P < 0.001, and 541 +/- 265 mg/dl, P < 0.0002, respectively) and asymptomatic infected subjects (3.4 +/- 2.1 mg/liter, P = 0.001, and 436 +/- 216 mg/dl, P < 0.0001, respectively) compared with the levels in healthy subjects (2.2 +/- 0.7 mg/liter and 204 +/- 113 mg/dl, respectively). Nonstatistically significant differences (P > 0.05) for concentrations of p24 antigen between asymptomatic infected patients (29 +/- 13 pg/ml) and AIDS patients (40 +/- 23 pg/ml) were observed. Total lymphocyte counts of 1,750 cells/microliters or less, CD4 counts of 200 cells/microliters or less, beta 2-microglobulin concentrations in serum of 4 mg/liter or higher, concentrations of IgA in serum of 450 mg/dl or higher, and the presence in serum of p24 antigen were correlated with elevated risks for developing AIDS. Monitoring both total lymphocytes and beta 2-microglobulin identified 91% of the AIDS patients; these assays may allow reductions in the annual number of CD4(+)-cell evaluations and the costs associated with monitoring both total lymphocytes and beta 2-microglobulin identified 91% of the AIDS patients; these assays may allow reductions in the annual number of CD4(+)-cell evaluations and the costs associated with monitoring the immune status of HIV-positive patients.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Endocytosis inhibition protects the isolated guinea pig heart against ouabain toxicity.

We have tested whether toxicity and uptake of ouabain are linked phenomena in isolated guinea-pig heart. We perfused toxic dose of either ouabain, dihydroouabain (hydrophilic cardiac steroids), ouabagenin or digitoxin (hydrophobic steroids) in conditions of endocytosis inhibited. We used two schemes of inhibition of endocytosis. First, we cooled the heart at 0-4 degrees C and exposed it 60 min to either 1 X 10(-6) M ouabain or 3 X 10(-7)M digitoxin. Upon rewarming, the heart exposed to ouabain relaxed with a shorter time constant than those exposed to digitoxin. Second, we perfused four receptor mediated endocytosis (RME) inhibitors at the same time that the cardiac glycosides. RME inhibitors significantly delayed the cardiac arrest caused by ouabain and dihydroouabain but they did not modify the toxicity of 3 X 10(-7)M digitoxin or 5 X 10(-6)M ouabagenin. None of RME inhibitors modified the toxicity of 0.5 mM K+ or zero Na+ saline solution. We suggest that the protection against ouabain toxicity brought by endocytosis inhibition, is related to the Na-pump recycling. We infer that besides the sarcolemmal exposed Na-pumps, the intracellular Na-pumps pool may be of importance for the pharmacological effects of digitalis steroids.

Animals↗
PubMed1996

Overnight dexamethasone pre-treatment improves the performance of the lysine-vasopressin test in the diagnosis of Cushing's syndrome.

OBJECTIVE: There is no endocrine test which is completely reliable for the confirmation of Cushing's syndrome and in separation of the various aetiologies. We have tested the hypothesis that overnight dexamethasone pre-treatment should result in a better performance of the lysine-vasopressin (LVP) test in the diagnosis of Cushing's syndrome. STUDY DESIGN AND PATIENTS: We studied 61 subjects, including 25 pituitary-dependent and 9 pituitary independent Cushing's (7 adrenal tumour and 2 ectopic ACTH syndromes), 18 euadrenal controls, 4 depressed subjects, and 5 cushingoid patients. The subjects received 1 mg of dexamethasone orally at 2300 h and the following morning they were given 10 IU of lysine-vasopressin im. MEASUREMENTS: Plasma cortisol (RIA) was measured at times -15, 0, 15, 30, 45, 60, 75, 90 and 120 minutes. RESULTS: The dexamethasone-modified LVP (Dx/LVP) test resulted in four patterns of cortisol response. The dexa sensitive pattern (positive suppression and negative response to LVP) was found in euadrenal subjects; the dexa insensitive pattern (negative suppression and positive response to LVP) was seen in Cushing's disease; a non-responsive pattern (negative suppression and negative response to LVP) was observed only in pituitary independent Cushing's; and an indeterminate pattern (positive suppression and positive response to LVP) was equivocal, being observed in 2 control subjects, 1 patient with Cushing's disease and 1 depressed patient. In separating control subjects from Cushing's syndromes the Dx/LVP test had 88.9% sensitivity, 100% specificity and 96.2% diagnostic accuracy; when the test was used to segregate Cushing's disease from control subjects we found 96.0% sensitivity, 100% specificity and 97.7% diagnostic accuracy. The performance variables for the Dx/LVP test in separating pituitary dependent from pituitary independent Cushing's were uniformly 100%. Depressed and cushingoid subjects did not differ from control subjects in their cortisol patterns during the test. Successful removal of the pituitary microadenoma in Cushing's disease was invariably followed by a reversal of the abnormal cortisol pattern (dexa insensitive) during the test to a dexa sensitive pattern indistinguishable from that of control subjects. CONCLUSION: These results confirm our hypothesis and suggest that an improved performance of any corticotroph stimulus (oCRH, LVP, AVP or desmopressin) in the diagnosis of Cushing's syndrome should result from pre-treatment with dexamethasone.

Cushing Syndrome↗
PubMed1995

[Cushing's syndrome: review of a national caseload].

Cushing's syndrome occurs rarely; in analyzing 50 cases studied at our institution we discuss the following aspects: syndromatic diagnosis, etiologic differentiation into the 3 categories of the syndrome, and therapeutic strategies for each variety. We postulate that non-endocrinologists should be responsible for the syndromatic diagnosis, easily done by using 2 simple tools: the measurement of basal free urinary cortisol and the performance of an overnight suppression of the adrenal axis with 1 mg of dexamethasone (Nugent's test). In contrast, the etiologic diagnosis and the therapeutic interventions should be strictly restricted to highly specialized institutions having well seasoned endocrinologists, a reliable endocrine laboratory, easy access to computed tomographies of the brain and abdomen as well as to nuclear resonance imaging of the brain. The usefulness of our in-house devised vasopressin challenge following overnight dexamethasone suppression for the etiologic diagnosis is highlighted. Neurosurgical expertise in the transsphenoidal approach to the pituitary gland as well surgeons well experienced in adrenal surgery are a must to offer a reasonable chance of success to patients with the syndrome. Forty one (82%) of the series were female patients, 78% were pituitary-dependent and 22% pituitary-independent Cushings. Six out of 8 (75%) of the adrenal tumors were carcinomas. Only 3 patients (6%) qualified as ectopic ACTH syndromes. The easiest variety to diagnose and treat was the adrenal adenoma (2 cases); adrenal carcinomas were always incurable. The ectopic ACTH syndrome was amenable to successful medical treatment with ketoconazole or surgical resolution with complete resection of the offending tumor (1 of 3 cases) or bilateral adrenalectomy (2 of 3 cases) Pituitary-dependent Cushings are quite tricky to diagnose and difficult to treat. Transsphenoidal resection of the offending microadenoma was successful in only 43.5% (10/23) of cases and we experienced 3 recurrences of the syndrome even after 8 years of successful removal of the pituitary adenoma. The remainder had to be cured by bilateral adrenalectomy. Seven out of 39 patients with Cushing's disease (18%) ultimately died for a variety of reasons; six out of 6 patients (100%) with adrenal carcinoma died of dissemination; two out of 2 adrenal adenomas cured and 1 out of the 3 ectopic ACTH syndromes died of dissemination of a malignant thymic carcinoma. We conclude that Cushing's syndrome is a serious, underdiagnosed disorder, which should be suspected and diagnosed by the non specialized physician and then referred to a specialized center for expert etiologic diagnosis and surgical therapy.

Cushing Syndrome↗
PubMed1995

[The effect of fluoxetine on insulin resistance in non diabetic obese patients].

Fluoxetine, a serotonin re-uptake inhibitor with antidepressive and appetite reduction effects, could improve insulin sensitivity. The aim of this work was to assess this effect of fluoxetine in obese subjects. We studied 12 subjects with a body mass index over 30, with a normal oral glucose tolerance test and not subjected to dietary restrictions. Insulin sensitivity using Bergman's minimal model, sex hormone binding globulin (SHBG) and insulin like growth factor binding protein 1 (BP 1) were evaluated before and after three weeks of treatment with 60 mg OD of fluoxetine. During treatment, subjects lost a mean of 1.9 kg. When compared with basal values, insulin sensitivity index (S1) improved significantly at the end of treatment (1.71 +/- 0.44 and 2.72 +/- 0.63 respectively), SHBG increased (28.9 +/- 5.1 and 18.2 +/- 3.4 nM/ml respectively) and BP 1 did not change (2.8 +/- 0.9 and 1.5 +/- 0.3 ng/ml respectively). The changes in insulin sensitivity did not correlate with weight changes (r = 0.4 NS). Weight or insulin sensitivity changes did not correlate with initial degree of insulin resistance. We conclude that the improvement in insulin sensitivity elicited by Fluoxetine is not related to weight changes and may be useful in the treatment of insulin resistant obese subjects.

Adult↗
PubMed1995

[Effect of a 17 beta estradiol gel preparation on hormone levels in menopausal women].

Different delivery forms of supplemental estrogens may differ in their hormonal effects. The aim of this study was to assess the effects of a daily dose of 2.5 g of 17 beta estradiol transdermal gel, given during four weeks, on hormone levels of six postmenopausal women. At the fourth week we observed a significant increase in estradiol and a decrease in FSH levels. Estrone levels also increased but the estradiol/estrone ratio was maintained in values over 1. No changes in SHBG or IGF1 levels were observed. Two patients that used the gel in the abdominal skin achieved lower estradiol levels (below 60 pg/ml). We conclude that the gel increased serum estradiol levels over 60 pg/ml in four of six women, that there is a big individual variability and the application zone could influence the serum estradiol levels achieved.

Administration, Cutaneous↗
PubMed1994

[Listeria infections and pregnancy].

One clinical case of lysteriosis during pregnancy, diagnosed in the puerperium period is analyzed. Both the mother and the newborn recovered favorably.

Adult↗
PubMed1994

[Improvement of insulin sensitivity associated with the prolonged use of Acipimox in ++a morbid obese patient].

Insulin sensitivity was estimated in a morbidity obese, insulin-resistant, glucose-intolerant patient before and after 4 weeks of treatment with Acipimox (250 mg t.i.d), an orally-administered, long-acting antilypolitic drug. The ensuing fall in circulating levels of fasting free fatty acids was associated with a clear amelioration of insulin resistance, as assessed by a minimal model analysis of a frequently sampled intravenous glucose tolerance test as well as by an oral glucose tolerance test. Similarly, this treatment brought about a reappearance of GH response to oral stimulation with clonidine. The evidence showing Acipimox-induced amelioration of insulin resistance in this patient without diet, exercise or weight loss should encourage exploring the potential utility of this drug in this type of patients.

Adult↗
PubMed1994

[The clinical estimate of adiposity is not a good predictor of insulin tissue sensitivity measured with a minimal model analysis].

Fifteen male volunteers, aged 30 to 40 years old, were classified according to body mass index (BMI) as lean (n = 5, BMI less than 20 kg/m2), normal (n = 5, BMI 20-25) or obese (n = 5, BMI over 30). Glucose intolerance was ruled out by a normal oral glucose tolerance test and insulin sensitivity (SI) and glucose effectiveness (SG) were estimated by a minimal model analysis of a frequently sampled intravenous glucose tolerance test modified by an intravenous insulin injection at minute 20. The MINMOD program was fed with 29 or 12 values (reduced sampling schedule). Despite a significant inverse correlation between BMI and SI (r = -0.533 p < 0.05), the latter parameter overlapped among groups and the correlation was lost when obese individuals were not considered. Waist/hip ratio correlated modestly with SI (r = -0.52 p < 0.05). SG did not correlate with BMI. Using the reduced sampling schedule. SI values had a correlation coefficient of 0.78 with those calculated using the usual sampling schedule, although they were 82% lower. We conclude that only a BMI of over 30 accurately predicts a low SI, and that waist/hip ratio does not have a better predictive power.

Adult↗