Biomedical subjects

R Sandoval

Publications and source records attributed to R Sandoval.

At least 19 recordsLinked to original sources

PubMed1997

Cellular mechanism of aminoglycoside tolerance in long-term gentamicin treatment.

In the rat, nephrotoxicity results from uptake of gentamicin at the apical membrane of proximal tubule (PT) cells. However, during continuous gentamicin treatment, the PT epithelium has been shown to recover. The mechanism(s) of cellular recovery and development of tolerance remains unknown. Therefore, we undertook studies designed to characterize cellular adaptations that occur during long-term gentamicin (LTG) treatment. After 19 days of gentamicin treatment, electron microscopy morphological evaluation revealed cellular recovery with an apparent mild decrease in height and number of microvilli. Enzymatic analysis of LTG PT membranes showed that apical and basolateral membranes had essentially returned to normal. Analysis of apical membrane lipid content revealed persistent statistically significant (P < 0.01) elevations in phosphatidylinositol (PI). In vivo immunogold morphological studies and biochemical studies in LTG rats revealed that endocytosis of gentamicin was selectively reduced, whereas the markers of fluid-phase (horseradish peroxidase) and receptor-mediated (beta2-microglobulin) endocytoses were unaffected or increased. Biochemical analysis showed that, although gentamicin binding to apical membranes isolated from LTG rats increased greater than twofold (P < 0.05) over membranes from untreated rats, in vivo cellular uptake, quantified with [3H]gentamicin, was reduced. Western blot analysis of LTG apical membranes and immunofluorescent staining of perfusion-fixed LTG kidneys showed no change in megalin levels or its apical membrane localization. These data imply that recovery of PT cells from and tolerance to LTG treatment involve a selective inhibition of gentamicin uptake across the apical membrane. They indicate that the mediators of gentamicin endocytosis were affected differently: PI levels increased, whereas megalin levels did not change. We conclude that selective inhibition of gentamicin uptake during LTG treatment is not affected by a reduction in PI or megalin levels. We postulate that trafficking of gentamicin and/or gentamicin-containing endocytic structures is reduced in LTG rats, allowing cells to develop tolerance to gentamicin.

Adaptation, Physiological↗

PubMed1995

Psychometric characteristics of the Wender Utah Rating Scale (WURS): reliability and factor structure for men and women.

The goals of this study were to examine the factor structure of the Wender Utah Rating Scale (WURS), to evaluate potential gender differences in factor composition, and to assess the reliability of the scale. The WURS was completed by 310 fathers and 305 mothers of children referred for evaluation of Attention-Deficit Hyperactivity Disorder (ADHD). For males, a five-factor solution (Conduct Problems, Learning Problems, Stress Intolerance, Attention Problems, Poor Social Skills/Awkward) accounted for 72 percent of the variance. There was also a five-factor solution for females (Dysphoria, Impulsive/Conduct, Learning Problems, Attention and Organizational Problems, Unpopular) which accounted for 71 percent of the variance. Symptoms of inattention and impulsivity loaded on separate factors for both men and for women. Test-retest reliability was examined with a different sample of 57 adults who completed the WURS on two separate occasions, 1 month apart. The WURS demonstrated satisfactory internal consistency and temporal stability, and it may be a useful tool for the study of ADHD in adults.

Adolescent↗

PubMed1995

Mal de Meleda.

A case of mal de Meleda originating in Chile is reported. The patient had no history of consanguinity and cases could not be detected in four generations of the patient's family. The palmoplantar keratoderma was progrediens and transgrediens, with distant hyperkeratotic plaques of the knees and elbows. The nails, hair, and teeth were normal.

Adult↗

PubMed1994

Psychometric properties of the children's atypical development scale.

The Children's Atypical Development Scale (CADS) is a 53-item rating scale designed to measure unusual behaviors in children. Principal-factor analysis on a clinic-referred and pediatric sample of 474 children resulted in a four-factor solution: Communication Deficits, Lability, Social Relatedness Deficits, and Preoccupation. The CADS is internally consistent and has adequate temporal stability. CADS factor scores were differentially associated with parent and teacher rating scales, IQ, and Continuous Performance Test errors. The scale shows promise as a clinical and research tool for assessing atypical behaviors associated with pervasive developmental disorder and other neurobehavioral disorders.

Adolescent↗

PubMed1994

Pigmented follicular cyst.

A pigmented follicular cyst is an infrequent variant of an epithelial cyst which has rarely been reported since it was first described about 10 years ago. The condition consists of a single pigmented lesion which occurs predominantly in adult men, and is usually located on the head and neck region. We report an example of a pigmented follicular cyst, which was located in the axilla.

Adult↗

PubMed1994

[Experience with prostaglandins E2 in intracervical gel and intravaginal tablets in fetal deaths].

Our clinical experience with E2 prostaglandins in intracervical gel and vaginal tablets to induce deliveries or abortions with dead fetuses is presented. The overall success rate of 50 patients was 70%, excluding 9 cases of anencephalos fetuses; the rate is increased to 77.7% in the cases of retained abortions and to 78.3% in the cases of dead fetuses in uterus after 20 weeks of gestation.

Abortion, Induced↗

PubMed1993

Psychotropic treatment of chronic fatigue syndrome and related disorders.

BACKGROUND: Chronic fatigue syndrome (CFS) and fibromyalgia frequently are associated with symptoms of major depression. For this reason, antidepressants have been used in treatment of these disorders; however, little direction has been provided into this application in psychopharmacology. METHOD: First, nine studies were reviewed regarding the relationship of the symptoms of fatigue and depression. Next, 23 reports (12 double-blind studies, 7 open studies, and 4 case reports) were reviewed for the effectiveness of therapy as assessed by global response and improvement of both depression and pain. Studies were differentiated by type of controls, as well as by alleged mechanism of action of the pharmacologic agent. RESULTS: Disturbances in brain neurochemistry shared by CFS and major depression may serve as a basis for the effectiveness of some antidepressants in CFS. Response to some antidepressants in patients with CFS or fibromyalgia may occur at doses lower than those used in major depression, e.g., amitriptyline 25-75 mg/day. We further found that the more serotonergic treatments (e.g., clomipramine) were more successful in alleviating pain than depression, whereas catecholaminergic agents (e.g., maprotiline, bupropion) seemed particularly effective for symptoms of associated depression. CONCLUSION: To maximize response of the physiologic and psychological consequences of the disorder, more investigation is needed to replicate the apparent findings that relate the neurochemical impairment underlying CFS and fibromyalgia to the type of antidepressant mechanism.

5-Hydroxytryptophan↗

PubMed1992

Bupropion treatment of fluoxetine-resistant chronic fatigue syndrome.

Chronic fatigue syndrome (CFS) includes many symptoms of major depression. For this reason, many antidepressants have been used to treat the symptoms of this disorder. Among the more recently released antidepressants are fluoxetine and bupropion. In this open study, nine CFS patients who either could not tolerate or did not respond to fluoxetine showed significant response when administered 300 mg/day of bupropion for an 8-week period in both rating of HDRS (t = 4.80, p < 0.01) and BDI (t = 2.48, p < 0.05). Furthermore, bupropion improvement in Hamilton Depression Rating Scale correlated significantly with change in plasma homovanillic acid (HVA) (r = 0.96, p < 0.01). Plasma total methylhydroxyphenolglycol (MHPG) also increased significantly during bupropion treatment (t = 2.37, p = 0.05). Measures of T1 microsomal antibodies also decreased over treatment time; increases in natural killer cell numbers correlated inversely with change in plasma levels of free MHPG (r = -0.88, p < 0.05). Bupropion responders were more likely to have trough blood levels above 30 ng/ml (chi 2 = 3.6, p = 0.05).

Adult↗

PubMed1992

[Strategy for monitoring and implementing methods for correcting child growth and development in rural areas of Sonora. Mexico].

An appropriate health technology to facilitate child growth and development in a rural area is presented and documented. Because mother's adequate behavior related to child's care does not produce immediate behavioral or physical changes it is necessary to create a long term social system of consequences. This was achieved joining a longitudinal measurement system with a program to train mothers to identify and deal with health and development issues. During four years, data were collected on weight-length development and morbidity twice a year and simultaneously skills were taught to diagnose treatment and prevent growth and development problems. After the third session child development and anthropometry data became the base of a system to assess maternal behavior, providing consequences for links in the behavior chains associated with child care. This system made organization and participation of the community in primary health care programs more likely, which implied a better score in each child growth and development chart.

Adult↗

PubMed1991

Beta-galactosidase fused to the hydrophobic domain of cytochrome b5 spontaneously associates with liposomes.

Since liver microsomal cytochrome b5 spontaneously associates with liposomes and membranes by means of its C-terminal hydrophobic domain (HP), chimeric proteins containing HP prepared by genetic fusion might also spontaneously associate with liposomes or cellular membranes. Synthetic DNA corresponding to the hydrophobic domain of cytochrome b5 was enzymatically fused in-frame to cloned DNA corresponding to the C-terminus of the Escherichia coli enzyme, beta-galactosidase. This protein, LacZ:HP, synthesized in E. coli and purified from a crude E. coli membrane extract, was shown to spontaneously associated with liposomes, as does cytochrome b5. Association is rapid and stable in the presence of salt and high pH and the fusion protein behaves as an integral membrane protein. LacZ:HP can be readily and extensively purified from crude extracts by association with liposomes and this procedure may provide a convenient purification scheme for proteins not otherwise readily purified, for example polypeptides from cloned gene fragments to be used for antibody production. These hybrid proteins may represent a new potentially useful class of polypeptides capable of hydrophobic interactions with membranes.

Amino Acid Sequence↗

PubMed1990

Diagnostic methods for peripheral arterial disease in the San Luis Valley Diabetes Study.

Peripheral arterial disease (PAD) is a frequent complication of diabetes mellitus. In the first phase of the San Luis Valley Diabetes Study, diagnostic criteria for PAD were evaluated in 607 controls and 343 diabetics. Normal ranges, and the lowest 2.5 percentile of the distribution of ankle/arm systolic blood pressure ratios were derived from a non-diabetic subset of the population with a very low probability of PAD. From this subgroup, abnormal ankle/arm ratios were defined as less than: 0.94 at rest, 0.73 after exercise, and 0.78 after reactive hyperemia. Using these criteria, PAD was identified in 130 subjects from the study population of 950 (prevalence of 13.7%). In contrast, a history of intermittent claudication, or an absent pulse in the extremity were uncommon findings in the study population, and thus had a low sensitivity and positive predictive value for PAD diagnosed by vascular laboratory criteria. We conclude that vascular laboratory tests provide a useful, and objective means of determining the prevalence of PAD in a geographically-based population of diabetic and control subjects.

Arteriosclerosis↗

PubMed1989

NIDDM and prevalence of nasal Staphylococcus aureus colonization. San Luis Valley Diabetes Study.

Previous studies of hospitalized and ambulatory patients have found a higher prevalence of Staphylococcus aureus nasal colonization in diabetic than nondiabetic subjects. We examined this association in a geographically based study among 551 residents of the San Luis Valley of Colorado and found no statistically significant increase in the relative risk of nasal S. aureus colonization in 188 non-insulin-dependent diabetic (NIDDM) versus 363 nondiabetic subjects (relative risk 1.3, 95% confidence limits 0.9-1.8). Adjustment for confounding by age, sex, ethnicity, county of residence, and frequency of hospitalizations or physician visits in the previous year did not affect the results. Among the diabetic subjects, S. aureus colonization was not associated with type of treatment for diabetes, level of glucose control, clinical duration of diabetes, or frequency of hospitalizations or physician visits in the previous year. In this population-based study, diabetes mellitus did not increase S. aureus nasal colonization, suggesting that factors other than diabetes mellitus may have caused the higher colonization rate found in previous clinic-based studies.

Colorado↗

PubMed1989

[Malignant pleomorphic fibrous histiocytoma of the lung. A clinical case].

A 44 year old woman presented with a bloody sputum, associated to bilateral lung nodules resembling metastatic lung carcinoma. The diagnosis of pulmonary malignant pleomorphic fibrous histiocytoma was made through an open lung biopsy. Histological considerations and a literature review related to this rare condition are induced.

Adult↗

PubMed1970