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Biomedical subjects

A Paredes

Publications and source records attributed to A Paredes.

At least 37 records · Page 2Linked to original sources
PubMed1997

Alcohol and cocaine interactions and aggressive behaviors.

This chapter presents (1) a review of several studies on the relationship between violent/aggressive behavior and the use of cocaine and/or the use of alcohol; and (2) findings from our study of cocaine-dependent men, illustrating deviant and violent behavior before and during cocaine addiction careers. As had been found in previous research, use of alcohol and cocaine seemed to increase the likelihood of the cocaine users in our sample engaging in deviant or violent behaviors. The extent of deviant or violent behavior, in our sample, during periods of cocaine use, periods of cocaine-alcohol use, periods of alcohol use only, and periods of abstinence for both alcohol and cocaine are discussed. Changes in the nature of the deviant or violent behaviors prior to and after the onset of cocaine addiction are also described.

Adolescent↗
PubMed1996

Cloning of an aquaporin homologue present in water channel containing endosomes of toad urinary bladder.

Regulation of total body water balance in amphibians by antidiuretic hormone (ADH) contributed to their successful colonization of terrestrial habitats approximately 200-300 million years ago. In the mammalian kidney, ADH modulates epithelial cell apical membrane water permeability (Pf) by fusion and retrieval of cytoplasmic vesicles containing water channel proteins called aquaporins (AQPs). To determine the role of AQPs in ADH-elicited Pf in amphibians, we have identified and characterized a unique AQP from Bufo marinus called AQP toad bladder (AQP-TB). AQP-TB possesses many structural features common to other AQPs, AQP-TB is expressed abundantly in ADH-responsive tissues, including toad urinary bladder and skin as well as lung, skeletal muscle, kidney, and brain. In a manner identical to that reported for the mammalian ADH-elicited water channel AQP2, AQP-TB expression is increased significantly by intervals of dehydration or chronic ADH stimulation. However, expression of AQP-TB protein in Xenopus laevis oocytes does not significantly increase oocyte Pf. The lack of expression of functional AQP-TB water channels in oocytes may result from intracellular sequestration of AQP-TB due to the presence of a YXRF sequence motif present in its carboxyterminal domain.

Amino Acid Sequence↗
PubMed1994

Osmoregulatory changes in myo-inositol content and Na+/myo-inositol cotransport in rat cortical astrocytes.

Exposure of cortical astrocytes to 325, 350, or 390 mosM culture media for 48 h caused a 1.4-, 2.1-, and 3.5-fold increase, respectively, in cellular content of the compatible osmolyte myo-inositol. Elevated myo-inositol levels accounted for approximately 56-100% of the solute needed by the cells for complete volume regulation under hypertonic conditions. Myo-inositol accumulation was associated with 4-5-fold (peak rate) and 1.8-2-fold (steady-state rate) increases in the rate of Na(+)-dependent myo-inositol uptake when cells were acclimated to 390 mosM culture medium for 12 h or 24-96 h, respectively. When medium osmolality was elevated by 25 mosM, peak and steady-state increases in myo-inositol uptake of 1.7-fold and 1.3-fold, respectively, were observed. Exposure to 390 mosM medium for 12-48 h induced a 3-8-fold increase in cotransporter mRNA levels suggesting that the increase in myo-inositol uptake is brought about by increased cotransporter gene expression. Abrupt return of hypertonic cells to an isotonic medium induced a rapid increase in myo-inositol efflux and a return of cotransporter mRNA to control values in < 2 h. In contrast, the cotransporter remained fully activated at hypertonic levels for 16 h. Between 16-24 h after the transfer, the rate of myo-inositol uptake returned to control values. The remarkable sensitivity of the cotransporter to hypertonic stress indicates that upregulation of myo-inositol transport in glial cells is likely to occur in a variety of disease states that cause an elevation of plasma osmolality. Slow downregulation of the cotransporter may be responsible in part for the slow loss of myo-inositol and cerebral edema that occurs with too rapid correction of chronic plasma hypertonicity.

Animals↗
PubMed1994

Water channel vesicles from toad urinary bladder contain a family of proteins present in other tissues.

Antidiuretic hormone (ADH) stimulation causes the fusion and subsequent retrieval of cytoplasmic vesicles containing water channels (WCV) with the apical membrane of toad bladder granular cells. Previously, we showed that purified WCV contain 12 major protein bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. To identify various WCV proteins, we screened a panel of mouse monoclonal antibodies and characterized an immunoglobulin G1 monoclonal antibody, 5E5, that recognizes integral membrane WCV proteins of 38, 33, and 31 kDa. Immunocytochemistry and Western blot analyses show that 5E5 binds to multivesicular body endosomes shown previously to contain ADH water channels. In addition, 5E5 recognizes these proteins in selected cells of the skin, intestine, liver, kidney, spleen, and lung. However, 5E5 does not appear to recognize components of the water channel itself. We conclude that WCV contain several membrane proteins recognized by 5E5 that are present in certain cells of the other organs. Monoclonal 5E5 provides a probe to determine the structure and function of these endosomal proteins as well as their role in the ADH water permeability response.

Animals↗
PubMed1994

Cellular subsets and epithelial ICAM-1 and HLA-DR expression in human papillomavirus infection of the vulva.

Cryostat sections of 20 clinical condylomata of the vulva induced by human papillomavirus and 5 normal control biopsies were examined using immunohistochemistry. The results indicated that in vulvar papillomavirus infection the intraepithelial Langerhans' cells showed abnormal morphology and a significantly lower density than controls. CD1a positive Langerhans' cells were also observed in dermis of condylomata, suggesting an abnormal epithelial traffic of dendritic cells. T lymphocytes with a mean CD4/CD8 ratio of 0.25 and a mean density of 267 +/- 59 cells/mm2 of epithelial section were the main cellular infiltrate in vulvar papillomavirus infection. Most of the T cells were HLA-DR negative. Those condylomata with moderate to severe mononuclear infiltrate showed leucocyte function antigen 1 positive T cells forming small clusters in the lower epithelial half around the ICAM-1 positive keratinocytes. Vulvar warts also showed epithelial areas with overlapped ICAM-1 and HLA-DR expression. Scattered T gamma-delta and B lymphocytes, macrophages and NK cells were observed among the cells of the dermal infiltrate of vulvar condylomata.

Adult↗
PubMed1993

The molecular structure of the antidiuretic hormone elicited water channel.

Measurements of osmotic water permeability (Pf) have shown that the plasma membranes of human red cells and certain epithelial cells possess specialized water channels. Although these water channels have been characterized extensively using biophysical techniques, the proteins that compose these unique channels have only recently been identified. Antidiuretic hormone (ADH) stimulation rapidly increases collecting duct epithelial cell Pf by fusion of water channel-containing vesicles (WCV) with their apical membranes. The proteins of WCV from toad bladder and rodent kidney have been characterized. The principal proteins in toad bladder WCV are 55,000 daltons (55 kDa) and 53 kDa and span the lipid bilayer of these vesicles. Polyclonal antisera raised against the 55-kDa and 53-kDa proteins inhibit ADH-stimulated toad bladder Pf by 80% and recognize protein bands of 46, 38 and 30 kDa in mouse kidney. Purification of WCV from rat kidney reveals enrichment of the 46-kDa protein. Recently, a 28-kDa integral membrane protein (called CHIP-28) has been isolated from human red cells. It forms functional water channels in Xenopus oocytes and when reconstituted into proteoliposomes. Large amounts of CHIP-28 protein are present in epithelial cells of the proximal tubule and descending thin limb of Henle's loop. Molecular cloning efforts are underway to elucidate the structure and function of these candidate water channel proteins.

Animals↗
PubMed1993

Relationship between types of human papillomavirus and Langerhans' cells in cervical condyloma and intraepithelial neoplasia.

Planimetric and immunohistologic studies of Langerhans' cells were performed on epithelial sheets dissected from paired biopsy specimens removed from histopathologically normal and abnormal areas of cervices infected by the human papillomavirus. The results showed that epithelial lesions associated with human papillomavirus types classically not related to malignancy (such as types 6 and 11) showed a similar decrease in the Langerhans' cell number to that induced by types 16 and 18. This phenomenon was analyzed in condylomas and cervical intraepithelial neoplasia of low degree, in which human papillomavirus DNA was detected by Southern blot. On the other hand, a significant decrease was observed in Langerhans' cell number in areas of condyloma and cervical intraepithelial neoplasia compared to normal (control) areas from the same patients. It was also confirmed that Langerhans' cell density increases along with the grade of intraepithelial neoplasia.

Adult↗
PubMed1993

Renal bone disease in pediatric and young adult patients on hemodialysis in a children's hospital.

Renal bone disease has been well defined in adult patients receiving chronic dialysis and in children on peritoneal dialysis/continuous ambulatory peritoneal dialysis. However, little is known about the histologic features in patients undergoing chronic hemodialysis in a children's hospital center. Twenty one patients, aged 17.5 +/- 1.5 yr, on hemodialysis for 35 +/- 6 months underwent iliac crest bone biopsies and deferoxamine infusion tests. Nineteen of 21 patients were receiving oral calcitriol. The 21 patients were classified by histomorphometry as follows: osteitis fibrosa, 5; mild hyperparathyroidism, 3; normal histology, 3; aplastic, 6; and mixed lesions, 4. Four of 21 patients were surface positive for aluminum, and seven other patients stained positive for iron in bone. Serum parathyroid hormone (PTH) levels correlated directly with the bone formation rate (r = 0.84) and with eroded bone perimeter (r = 0.67). Eight of the nine patients with serum PTH levels above 125 pg/mL had marrow fibrosis. All patients with serum calcium levels < 10.0 mg/dL and serum PTH levels > 125 pg/mL had either osteitis fibrosa or mixed bone lesions--a group of patients that might benefit from aggressive vitamin D therapy. In contrast, an examination of patients with serum calcium levels > 10.0 mg/dL and serum PTH levels < 65 pg/mL correctly identified three out of three patients with aluminum-related bone disease. These findings suggest that measurements of serum intact PTH levels by the immunoradiometric assay method may be valuable in distinguishing high-turnover lesions from normal or low-turnover skeletal lesions in this population.

Adolescent↗
PubMed1993

Recent developments in alcoholism:molecular biology and behavior.

Following our initial observation that the A1 allele of the D2 dopamine receptor (DRD2) gene was associated with alcoholism, a number of studies, both in the United States and abroad, have attempted to replicate and extend this finding in different Caucasian populations. In nine independent studies containing a total of 491 heterogeneous alcoholics (less severe and severe) and 495 heterogeneous controls (assessed and unassessed for alcoholism), the prevalence of the A1 allele was 43.0% in the former group compared with 25.7% in the latter groups (odds ratio = 2.18, p < 10(-6). The prevalence of the A1 allele increased to 56.3% in a more homogeneous sample of 158 severe alcoholics (odds ratio = 3.32, p < 10(-8)). Moreover, the B1 allele of the DRD2 gene was also found to be significantly associated with severe alcoholism. Additional data are accruing which also implicate the DRD2 A1 and B1 alleles in substance use disorders other than alcoholism. If further studies continue to support the results currently available, they would indicate that the DRD2 gene is the most prominent single gene determinant of susceptibility to severe substance abuse. However, the larger role still appears to be played by a combination of environmental factors and as yet unidentified genes.

Alcoholism↗
PubMed1992

The role of alcohol in cocaine dependence.

The relationships between the patterns of alcohol and cocaine use are examined using information derived from the authors' research data and from the literature. Excessive alcohol drinking was very prevalent among males seeking treatment for cocaine dependence at a Veterans Administration hospital in West Los Angeles. Fifty percent met DSM-III-R criteria for alcohol dependence. The drug-related behaviors of patients with the diagnosis of dependence on cocaine only were compared with those of patients dependent on cocaine and alcohol. The progression of the cocaine addiction was not significantly different in those two groups. However, patients with dependence on cocaine and alcohol were more likely to be users of other drugs of abuse. Concerning psychosocial behaviors, both groups maintained employment and stable interpersonal relationships throughout significant periods of their addictive career. One year after drug treatment, both subsamples showed significant improvement in terms of cocaine and alcohol use and social adjustment. Research implications and the possibility that both dependent conditions may share neurobehavioral reinforcing mechanisms are discussed.

Adult↗
PubMed1992

Dual-diagnosis empirical and developmental-humanistic approaches.

The association between alcohol and/or drug dependence and major psychiatric conditions such as schizophrenia has received increased attention from the professional community. Terms such as "dual diagnosis" used to designate these clinical occurrences have become common, reflecting the interest mentioned. This chapter reviews the prevalence of the association between substance abuse and psychiatric disorder, the nature of the interactions observed, and some of the implications for patient care and health policy. Following this empirical perspective, we present a developmental-humanistic approach that has been used in the psychotherapeutic management of these problems. Our review of information on dual diagnosis suggests that the association between the two processes--substance abuse and psychiatric disorder--is not fortuitous or just the result of environmental conditions. There are complex physiopathological links at the neurobiological level that deserve research attention.

Alcoholism↗
PubMed1992

Assessment by planimetry of Langerhans' cell density in penile epithelium with human papillomavirus infection: changes observed after topical treatment.

Langerhans' cells could have an important role in the immune surveillance for the malignant transformation associated with certain viral infections. A planimetric study of Langerhans' cells was performed on epithelial sheets obtained from male and female patients who presented with human papillomavirus-induced condylomata. Preliminary epidemiological studies have indicated that after a human papillomavirus infection the risk of malignant transformation is higher in the cervix than in the penis. Our study was designed in such a way that the Langerhans' cell density observed in condylomata could be compared to that detected in adjacent normal areas from the same patients. The results showed that a highly significant decrease in Langerhans' cells occurred in male and female human papillomavirus infected genital tracts. In the penis the local treatment with 5-fluorouracil restored the normal Langerhans' cell density. The significance of these findings in relationship with malignant transformation is discussed.

Administration, Topical↗
PubMed1992

Effect of fluoxetine on alcohol consumption in male alcoholics.

To test the effect of inhibiting serotonin uptake on voluntary alcohol intake, 20 alcohol-dependent males were housed on a locked hospital ward with 60-ml drinks of 97.5 proof alcohol available in a fixed interval drinking decision paradigm 13 times each day. After a 3-day, single-blind placebo baseline period, 10 subjects each received the serotonin uptake blocker fluoxetine (up to 80 mg po daily) or placebo double-blind for 28 days. The fluoxetine group had a 14% lower alcohol intake during the 1st week only, associated with a lower proportion of requests for alcohol and less craving for alcohol (as rated by research staff). There were no significant effects in later weeks, nor any differences in scores on the Hamilton Depression and Anxiety Scales or the Hopkins Symptom Checklist.

Adult↗
PubMed1992

Osmoregulation of Na(+)-inositol cotransporter activity and mRNA levels in brain glial cells.

During plasma hypertonicity brain volume is regulated acutely by electrolyte uptake and chronically by accumulation of organic solutes such as inositol. Cultured rat C6 glioma cells, an astrocyte-like cell line, show a similar pattern of volume control. Volume regulatory accumulation of inositol requires external inositol, indicating that membrane transport plays a central role in this process. The inositol uptake pathway is Na+ dependent and exhibits Michaelis-Menten kinetics. Chronic hypertonic acclimation results in a twofold increase in the maximum velocity of the transporter without changing the Km. Hypertonic stress also results in a 17-fold increase in transporter mRNA. Elevation of mRNA levels precedes activation of the transporter by 4-6 h, suggesting that increased inositol uptake is mediated by synthesis and membrane insertion of new transport proteins. Reacclimation of hypertonic cells to isotonicity causes a rapid reduction of transporter mRNA levels to control levels within 4 h. In contrast, downregulation of transport activity does not begin until between 10 and 24 h after reexposure to isotonicity.

Animals↗