Search PubMed⌕ Search

Biomedical subjects

J C Alvarez

Publications and source records attributed to J C Alvarez.

At least 37 records · Page 2Linked to original sources

Transabdominal surgical approach in the management of renal tumors involving the retrohepatic inferior vena cava.

Multiple reports over the last decade have documented the clear superiority of surgery over other alternative treatments in the management of renal cell carcinoma with extension into the inferior vena cava (IVC). Controversy persists, however, regarding the management of tumor thrombus that extends retrohepatically, but not entering the right atrium. In this report, we retrospectively review our experience with the use of a feasible transabdominal technique without any form of bypass or anticoagulation for safe removal of renal tumor involving the retrohepatic IVC. From 1988 to 1998, 132 patients with renal cell carcinoma underwent radical nephrectomies at the urology service of our hospital. Five patients (3.8%) had retrohepatic venous extension through the renal vein into the IVC. Our transabdominal approach was accomplished by complete mobilization of the liver, control of the hepatocaval connection, total vascular exclusion of the IVC without heparin administration, removal of the tumor thrombus, and primary closure of the longitudinal vena cavotomy. From our results, we found the transabdominal approach with total vascular exclusion of the IVC to be satisfactory, with no early deaths, acceptable morbidity, and a remarkable limitation of blood loss and transfusion requirements.

Adult↗

[Thyroid cancer treatment].

INTRODUCTION: Thyroid diseases are common although cancer is rare. There are some controversial issues concerning the extent of surgical treatment of thyroid cancer. MATERIALS AND METHODS: We have studied 614 cases of thyroidectomy inducing 82 of mostly papillary and follicular thyroid cancers. RESULTS AND DISCUSSION: We observed that differentiated thyroid cancer has a predilection for the right lobe and one third of papillary tumors are multifocal. We have seen that fine needle aspiration cytology is the most useful preoperative study. Intraoperative frozen biopsy has a good specificity but sensitivity is low in our series, specially for follicular neoplasms. The treatment in our series consisted in total thyroidectomy and, in differentiated cancers, postoperative I-131. Survival is very good for differentiated cancers. Prognosis is poor for anaplastic carcinoma in the short term.

Adolescent↗

Argentine plants as potential source of insecticidal compounds.

CH2Cl2 and MeOH extracts of 15 Argentine plants used locally as insecticides, were evaluated for their insecticidal activity. Chenopodium multifidum L. (Chenopodiaceae); Flaveria bidentis (L.) O.K. (Compositae); Aristolochia argentina Gris. (Aristolochiaceae) and Tagetes erecta L. (Compositae) showed a significant activity against Sitophilus oryzae.

Analysis of Variance↗

CSF 5-HIAA levels are lower in impulsive as compared to nonimpulsive violent suicide attempters and control subjects.

BACKGROUND: We studied CSF 5-HIAA and HVA concentrations in violent suicide attempters and examined their relationship with depression, anxiety, and impulsivity. METHODS: CSF 5-HIAA and HVA concentrations were determined very shortly after hospital admission and compared to those of a matched control population. Clinical evaluation was performed concomitantly; the level impulsivity was evaluated by the Impulsivity Rating Scale (IRS). RESULTS: Twenty-three patients and 23 control subjects were included. According to the IRS, 14 patients were classified as impulsive, including all patients suffering from personality disorders, and 9 as nonimpulsive, with a main DSM-IIIR diagnosis of melancholia. CSF 5-HIAA concentrations in the suicide group were significantly lower than in control subjects. This difference was entirely due to the impulsive suicide attempters. There was an inverse correlation between the IRS score and CSF 5-HIAA (r = -.47, p = .02) and only a trend for HVA (r = -.41, p = .078) levels in the suicide group. CONCLUSIONS: This study of a group of violent suicide attempters distinguished a subgroup of patients diagnosed with personality disorder with high impulsivity scores and a subgroup of patients with the main diagnosis of severe depression. CSF 5-HIAA was significantly lower in impulsive violent attempters than in nonimpulsive violent attempters, therefore desintangling violence from impulsivity and linking this biologic abnormality to impulsivity.

Adult↗

Low blood cholesterol and low platelet serotonin levels in violent suicide attempters.

AIM OF THE STUDY: This study investigated the possible connection between serum cholesterol levels and platelet serotonin (5-HT) content in violent suicide attempters and matched controls. METHODS: Blood samples for cholesterol and platelet 5-HT levels were obtained from 17 drug-free patients within 3 days after the suicide attempt. RESULTS: Serum cholesterol and platelet 5-HT levels in the suicide attempters were significantly lower than in the controls; however, we did not find any significant correlation between these two variables. Indeed, three clinical dimensions are present in this patient group: suicidality, violence, and impulsiveness. Because we did not find a difference in cholesterol and platelet 5-HT levels between impulsive and nonimpulsive patients, these two indexes may more reflect the dimension of suicidality and/or violence. CONCLUSIONS: Further investigation is necessary to study the dependence of these two peripheral abnormalities within the context of violent suicidal behavior.

Adult↗

Simultaneous measurement of dopamine, serotonin, their metabolites and tryptophan in mouse brain homogenates by high-performance liquid chromatography with dual coulometric detection.

A new rapid and sensitive high-performance liquid chromatography (HPLC) method for the simultaneous determination of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), 3-methoxytyramine, 5-hydroxytryptamine (serotonin), 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid and tryptophan has been developed and applied to mouse frontal cortex, caudate nucleus and dorsal raphe assays. A dual coulometric detector was used with detection at +0.25 and +0.55 V, which allowed the determination of tryptophan. Detection limits for all compounds (0.8-9.0 pg per injection, depending on the compounds) were useful for this application. Owing to great sensitivity of the method, the brain tissue samples can be very small, less than 2 mg. Linearity of standards was excellent (r > 0.999 in all cases). Intraday and interday precisions for samples analytes were generally acceptable (intraday assay CV < 8.7% and interday assay CV < 7.0% except for DOPAC and 5-HIAA, which was 11.4% for the low concentrations). Average recoveries of standard additions to sample analytes were > 90%. Attention was paid to stability of standard and sample analytes when stored at +4 degrees C or at -70 degrees C with two different homogenizing agents (0.1 M HClO4 with 10(-7) M ascorbic acid and 0.05 M HClO4 without ascorbic acid). This simple, rapid and efficient method can be used as a basic research tool for modification of brain neurotransmitters in experimental pharmacological protocols for following psychotropic drug treatments in animals.

Animals↗

Plasma serotonin level after 1 day of fluoxetine treatment: a biological predictor for antidepressant response?

RATIONALE: Antidepressant treatments present a delayed onset of action. OBJECTIVE: The present study investigated whether plasma or serum serotonin, 5-hydroxytryptamine (5-HT), could predict clinical improvement. METHODS: Biological parameters were determined after a 4-week drug-free period (day 0) and 1, 14 and 28 days after the beginning of the treatment with fluoxetine 20 mg daily in depressed patients. Clinical evaluations were assessed on days 0, 14 and 28. RESULTS: One day after a single dose, the mean values of plasma 5-HT (5.4 +/- 2.6 nmol/l) and serum 5-HT (484 +/- 215 nmol/l) were not statistically different from basal mean values (4.5 +/- 2.5 nmol/l and 523 +/- 263 nmol/l, respectively). The repeated treatment significantly reduced serum 5-HT to 34% (P = 0.002) and 17% (P = 0.0004) of pretreatment values after 14 and 28 days of treatment, respectively; plasma 5-HT was also reduced significantly to 28% and 15% of pretreatment values (P < 0.05 in both cases). At day 28, four of the eight patients responded by showing a reduction in MADRS score of at least 50% of the baseline score. No correlation was found between pretreatment values of serum or plasma 5-HT and clinical evolution, even if a tendency (P < 0.07) to lower serum 5-HT pretreatment values was observed in responders. Plasma 5-HT after 1 day of treatment was significantly different between responders and non-responders: the plasma 5-HT concentration in responders was 3.4 +/- 1.7 nmol/l versus 7.4 +/- 1.6 nmol/l in non-responders (P = 0.02). Moreover, plasma 5-HT levels after 1 day of treatment were positively correlated to the final MADRS score (r = +0.89, n = 8, P = 0.003) and inversely correlated to its change from the initial score (r = -0.76, n = 8, P = 0.02). CONCLUSION: These preliminary data show that fluoxetine and norfluoxetine might influence 5-HT peripheral venous blood parameters and that plasma 5-HT after 1 day of treatment might be a biological predictor for antidepressant response.

Adult↗

Differential changes in brain and platelet 5-HT concentrations after steady-state achievement and repeated administration of antidepressant drugs in mice.

The aim of the study was to compare in male NMRI mice the simultaneous evolution of blood serotonin (5-HT) concentrations, which correspond to 99% of platelet 5-HT content, and 5-HT parameters in the dorsal raphe, caudate nucleus and frontal cortex after clomipramine, fluoxetine and moclobemide treatments. After steady-state concentrations of the three compounds were reached, the 5-HT levels were significantly enhanced vs. saline-treated mice in the three brain areas studied. Tryptophan (TRP) levels in the three brain areas were significantly increased with clomipramine and fluoxetine but not with moclobemide. A significant decrease in the metabolite 5-hydroxyindoleacetic acid (5-HIAA) levels was observed only with moclobemide. After 14 days of treatment, 5-HT levels in all areas studied were found to be enhanced only with moclobemide while TRP and 5-HIAA levels were not different under the three drug regimes from those of controls. After 21 days of treatment, 5-HT levels were found enhanced only with moclobemide in the nerve terminal regions. An important depletion in platelet 5-HT content was observed after clomipramine and fluoxetine treatments at day 14 and day 21 and a significant increase was observed after moclobemide treatment at day 14 with a return to initial values after 21 days. Our results show significantly different effects between central and peripheral indices of 5-HT metabolism according to time and to the antidepressant assessed: (i) an enhancement of total tissue 5-HT levels in the three brain areas studied after steady-state achievement of the 3 antidepressants, (ii) the return to initial values of brain 5-HT levels after repeated administration of the two 5-HT re-uptake inhibitors, consistent with the presence of brain adaptative mechanisms, with a concomitant dramatic decrease of platelet 5-HT content and (iii) an apparent gradual attenuation of the brain and periphery MAOI-A effect induced by moclobemide with 5-HT levels remaining elevated only in 5-HT nerve terminal regions.

Animals↗

Decreased platelet serotonin transporter sites and increased platelet inositol triphosphate levels in patients with unipolar depression: effects of clomipramine and fluoxetine.

BACKGROUND: The central serotonergic system has been implicated in the pathophysiology of depression and in the mechanism of the action of antidepressant drugs. The human platelet has been proposed as a peripheral model of central serotonergic neurons. METHODS: Six peripheral serotonergic parameters were determined simultaneously in 27 patients with unipolar depression before and after 2, 4, and 12 weeks of clomipramine or fluoxetine treatment according to the psychiatrist. RESULTS: In patients with depression versus matched control subjects, platelet [3H]paroxetine binding sites were found to be significantly decreased (2.10 +/- 0.70 versus 3.88 +/- 0.77 fmol/10(9) platelets; P = .0001), platelet serotonin (5-HT) content was found to be significantly decreased (1.90 +/- 1.52 versus 2.74 +/- 1.12 nmol/10(9) platelets; P = .001), and platelet inositol triphosphate levels were found to be significantly increased (2.85 +/- 0.70 versus 1.85 +/- 0.77 fmol/10(9) platelets; P = .0001). No significant difference between patients and control subjects was found for platelet [3H]-lysergic acid diethylamide ([3H]LSD) binding sites, aggregation tests with 5-HT or adenosine diphosphate and plasma 5-HT levels. Treatment with both clomipramine and fluoxetine gradually further reduced the density of platelet [3H]paroxetine binding sites and induced a dramatic decrease in platelet and plasma 5-HT levels. With clomipramine, the decreased blood 5-HT levels are associated with increased platelet [3H]LSD binding sites and aggregation responses. After 12 weeks, nonresponders to both treatments had platelet inositol triphosphate levels that were still increased (2.81 +/- 0.75 fmol/10(9) platelets) when responders levels were not different from those of control subjects (1.41 +/- 0.45 versus 1.70 +/- 0.25 fmol/10(9) platelets). CONCLUSIONS: Drug-free patients with depression had simultaneously decreased 5-HT transporter (5-HTT) sites and overstimulated phosphoinositide signaling systems. Clomipramine and fluoxetine treatments, which further decreased the density of 5-HTT sites, allowed platelet inositol triphosphate levels to return to normal values only in responders.

Adult↗

Spanish population data on the loci D13S317, D7S820, and D16S539 generated using silver staining (SilverSTR III Multiplex).

A set of 212 samples from unrelated Spanish Caucasians living in Andalucia (southern Spain) were analyzed with a new commercially-available kit for multiplex amplification of 3 STR loci (D13S137, D7S820, and D16S539), manual denaturing polyacrylamide gel electrophoresis and silver staining. These three loci are of special interest for the forensic community since they are a part of the 13 CODIS-core STR loci. The results show that the loci D13S317 and D16S539 meet Hardy-Weinberg expectations (HWE), but the locus D7S820 did not meet HWE (p = 0.003). However, there was no detectable departures from independence (i.e., linkage disequilibrium) between any pair-wise combination of loci. The D7S820 data were further investigated. The excess homozygosity was due to an excess of D7S820 10, 10 homozygotes. To determine if the allele frequency data are meaningful and can be applied to forensic identity cases, the Spanish D7S820 allele frequency data were compared with four other Caucasian sample populations. The D7S820 allele frequencies were statistically similar; thus, the results support that the allele frequency data can be used reliably for estimating DNA profile frequencies.

Alleles↗

Fluorescent multiplex analysis of nine STR loci: Spanish population data.

A total of 171 Caucasians living in Andalucia (southern Spain) have been typed for nine short tandem repeat (STR) loci by multiplex PCR amplification using a commercially available kit (Profiler Plus; Perkin-Elmer, Norwalk, CT, USA) and semi-automatic electrophoresis (ABI Prism 377 DNA Sequencer, Applied Biosystems, Foster City, CA, USA). The kit enables typing of the STR loci D3S1358, VWA, FGA, D5S818, D13S317, D7S820, D8S1179, D21S11, and D18S51. All loci, except D7S820, meet Hardy-Weinberg equilibrium. Because of the large number of loci that can be analyzed, the power of discrimination (PD) is greater than 0.99999, and the probability of exclusion (PE) reaches 0.99991 in our population sample.

Alleles↗

Determination of fluoxetine and its metabolite norfluoxetine in serum and brain areas using high-performance liquid chromatography with ultraviolet detection.

A high-performance liquid chromatography (HPLC) method using only 0.1 ml of serum or homogenate from brain areas has been developed for the determination of fluoxetine (FLU) and its metabolite, norfluoxetine (N-FLU), with ultraviolet detection at 227 nm. The small volume of sample required in this method allows studies in small animals, such as mouse. The method provides recoveries of up to 90% for both compounds. Acceptable coefficients of variation were found for both within-run and day-to-day assays. The limit of detection was 5.0 ng/ml. No interferences were found with tricyclic antidepressant drugs and benzodiazepines, which allows this method to be used in clinical studies, Pharmacokinetic parameters for the two compounds are reported in mouse serum, frontal cortex and caudate nucleus. We also report the values of FLU and N-FLU in serum from humans who were treated once daily with 20 mg of FLU, obtained after 1, 14 and 28 days of treatment.

Animals↗

Neuronal loss in human medial vestibular nucleus.

The data concerning the effects of age on the brainstem are inconsistent, and few works are devoted to the human vestibular nuclear complex. The medial vestibular nucleus (MVN) is the largest nucleus of the vestibular nuclear complex, and it seems to be related mainly to vestibular compensation and vestibulo-ocular reflexes. Eight human brainstems have been used in this work. The specimens were embedded in paraffin, sectioned, and stained by the formaldehyde-thionin technique. Neuron profiles were drawn with a camera lucida at x330. Abercrombie's method was used to estimate the total number of neurons. We used the test of Kolmogorov-Smirnov with the correction of Lilliefors to evaluate the fit of our data to a normal distribution, and a regression analysis was performed to determine if the variation of our data with age was statistically significant. The present study clearly shows that neuronal loss occurs with aging. The total number of neurons decreases with age, from 122,241 +/- 651 cells in a 35-year-old individual to 75,915 +/- 453 cells in an 89-year-old individual. Neuron loss was significant in the caudal and intermediate thirds of the nucleus, whereas the changes in the rostral third were not significant. The nuclear diameter of surviving neurons decreased significantly with age. There is a neuron loss in the MVN that seems to be age-related. It could help explain why elderly people find it hard to compensate for unilateral vestibular deficits. The preservation of neurons in the rostral third could be related to the fact that this area primarily innervates the oculolmotor nuclei; these latter neurons do not decrease in number in other species studied.

Adult↗

Metastatic squamous cell carcinoma in cervical lymph nodes from an unknown primary tumour: prognostic factors.

The aim of this retrospective review is the study of the prognostic factors related to cervical metastases of squamous cell carcinoma from an unknown primary tumour. Sixty-seven patients were selected and surgery and postoperative radiotherapy was the treatment used. Nineteen tumours were subsequently found (27%). The 5-year actuarial survival rate of all patients was 22%. Survival rates were significantly related to lymph node stages and to the histological degree of differentiation. Nevertheless, actuarial survival rates were not related to the appearance of the primary tumour (P = 0.07). In our series, the single most important prognostic factor was the neck stage. The value close to statistical significance observed when the primary tumour subsequently appeared (P = 0.07), suggests that this could worsen the prognosis.

Actuarial Analysis↗

Dandruff as a potential source of DNA in forensic casework.

Dandruff is a clinical alteration of the skin that consists histologically of orthokeratotic clumps with minute parakeratotic foci found in inflammatory pathologies such as seborrheic dermatitis and psoriasis. Therefore, some nucleated cells should be found in dandruff and hence there is a possibility that forensically typeable DNA could be extracted from dandruff. Because of a particular case in which we were involved, a study was carried out to determine whether or not DNA could be extracted from dandruff, and if the two most widely used extraction techniques (Chelex and organic) would be applicable. Results show that sufficient quantities of DNA (more than 30 to 40 ng) can be obtained from as little as 1.0 to 1.5 mg of dandruff. Both methods yield DNA, although the organic procedure seems to yield more (72.5 ng Chelex vs. 183.3 ng organic). All the DNA samples extracted were typed correctly for the loci HUMTH01 and HUMvWA. Therefore, dandruff can be considered a potential source of DNA for forensic identification.

Clothing↗

Morphometric analysis of the human vestibular nuclei.

BACKGROUND: Cytoarchitectural investigations of the vestibular nuclei have been undertaken in different species of mammals. These data provide a description of the general architecture of the nuclei but limited information about quantitative characteristics of their cell population. We have recently obtained data about the morphometric parameters of the vestibular nuclei neurons in some species. The application of quantitative image analysis techniques to the research of the cellular morphology in the vestibular area of humans might provide basic information to compare with data from animal studies, taking into account the observed correlation between physiological and morphological properties of vestibular neurons. METHODS: The characteristics of the major vestibular nuclei in humans have been studied with light microscopic techniques in serially cut sections. Camera lucida drawings of the vestibular nuclei and their neurons were made and subjected to computerized image analysis. For each vestibular nucleus, information was obtained about topography, morphological characteristics (i.e., location, volume, and length), and the number and morphometric parameters of their neurons (cross-sectional areas, maximum and minimum diameters). Morphometric data about cell parameters were statistically analyzed by comparing the populations within different parts of each nucleus and from different nuclei. RESULTS: Among the vestibular nuclei, the medial, which is the largest, has the greatest number of neurons, and the interstitial, the least. The lateral and interstitial nuclei contain the largest cells, and the descending nucleus has the smallest cells. The superior nucleus contains cells of intermediate size. The size of cells decreases in a rostrocaudal direction in the medial, lateral, and descending nuclei, the opposite trend being observed in the superior nucleus. Within the superior and medial nuclei, there are discrete areas with cells with distinctive characteristics. CONCLUSIONS: These results suggest that, just as most of the anatomical characteristics of the second-order neurons found in animals have been preserved in humans, so the physiological mechanisms observed in the vestibular system of animals should apply to humans.

Adult↗