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Biomedical subjects

A Rodriguez

Publications and source records attributed to A Rodriguez.

At least 163 records · Page 9Linked to original sources
PubMed1998

Earlier onset of Alzheimer's disease in men with Down syndrome.

BACKGROUND: Virtually all individuals with Down syndrome (DS) have neuropathologic changes characteristic of Alzheimer's disease (AD) beginning at 40 years of age. Few studies have examined factors that influence age at onset of AD in DS. We investigated whether sex differences in age at onset and risk of AD among adults with DS are similar to those observed in the general population and whether the effect of sex on risk of AD is modified by apolipoprotein E (APOE) genotype. METHODS: A community-based sample of 111 adults with cytogenetically confirmed DS (34 to 71 years of age) was ascertained through the New York State Developmental Disabilities system. A semistructured interview with caregivers and review of medical records was used to ascertain the presence or absence of AD. APOE genotyping was carried out without knowledge of the subject's medical history or clinical diagnosis. RESULTS AND CONCLUSIONS: Both male gender and the presence of an APOE epsilon4 allele were associated with an earlier onset of AD. Compared with women, men with DS were three times as likely to develop AD. Compared with those with the APOE 3/3 genotype, adults with DS with the 3/4 or 4/4 genotypes were four times as likely to develop AD. No individual with an APOE epsilon2 allele developed AD. No evidence of interaction of sex and APOE genotype was found in risk of AD. The higher risk of AD in men may be related to differences in hormonal function between men and women with DS that are distinct from those in the general population.

Adult↗
PubMed1998

Prevalence of chronic medical conditions in adults with mental retardation: comparison with the general population.

We interviewed caregivers and reviewed medical records of 278 adults with mental retardation with and without Down syndrome, 45 to 74 years of age. Standardized morbidity ratios were used to compare frequency of medical disorders in these adults to frequency in the general population. In adults with mental retardation, the frequency of common age-related disorders was comparable to that in the general population, but there was an increased frequency of thyroid disorders, nonischemic heart disorders, and sensory impairment. Surveillance of health status and increased access to health care for screening and treatment of age-related disorders that are more frequent in adults with mental retardation would be important to prevent the development or delay the impact of these conditions and to promote healthy aging.

Adult↗
PubMed1998

Delta6- and delta5-desaturase activities in the human fetal liver: kinetic aspects.

Delta6- and delta5-desaturase activities were studied in human fetal liver microsomes obtained after legally approved therapeutic abortion. Enzyme activities were measured by a radiochemical method using reverse-phase high performance liquid chromatography (HPLC). Free and phospholipid fatty acids were assessed in each liver sample by a combination of thin-layer chromatography (TLC) and gas-liquid chromatography (GLC) procedures. The kinetic measurements showed higher delta6-desaturase activity for the n-3 series than for the n-6 series. Apparent Km of 6.5, 3.9, and 24.5 microM and Vm of 7.5, 9.1, and 24.4 pmol x min(-1) x mg(-1) were obtained, respectively, for 18:2n-6 delta6-, 20:3n-6 delta5-, and 18:3n-3 delta6-desaturases. Beyond 30, 20, and 60 microM of 18:2n-6, 20:3n-6, and 18:3n-3 concentration, respectively, the enzyme activity deviated from Michaelis-Menten kinetics, suggesting an inhibition by excess substrate which is unlikely to occur in vivo as endogenous substrate concentration is much lower. We observed a breakdown in linearity between desaturase activity and microsomal protein concentration beyond 4-5 mg microsomal protein, whatever the enzyme or substrate. Both this phenomenon and the inhibition due to excess substrate should be taken into account in the determination of delta6- and delta5-desaturase activities. Comparison of concentrations of the respective endogenous substrates and the kinetic constants of each enzyme suggested that the higher delta6-desaturase activity observed for the n-3 series than for the n-6 series is not physiologically relevant in human fetal liver.

Delta-5 Fatty Acid Desaturase↗
PubMed1997

The 18-wheeler mutation reveals complex antibacterial gene regulation in Drosophila host defense.

Mammals and insects employ similar Rel/NF-kappaB signaling cascades in their humoral immune responses. The mammalian interleukin-1 type I receptor (IL-1R) is one way of activating this cascade. The Drosophila Toll protein, whose cytoplasmic domain shows striking similarity to that of the IL-1R, acts in the humoral antimicrobial response. Here we demonstrate that a second IL-1R-related Drosophila protein, 18-Wheeler (18W), is a critical component of the humoral immune response. 18-wheeler is expressed in the larval fat body, the primary organ of antimicrobial peptide synthesis. In the absence of the 18W receptor, larvae are more susceptible to bacterial infection. Nuclear translocation of the Rel protein Dorsal-like immunity factor (Dif) is inhibited, though nuclear translocation of another Rel protein, Dorsal, is unaffected. Induction of several antibacterial genes is reduced following infection, relative to wild-type: attacin is reduced by 95%, cecropin by 65% and diptericin by 12%. Finally, 18-wheeler (18w) expression is induced in response to infection and, in addition to the receptor form, four immune-specific transcripts and proteins are produced.

Animals↗
PubMed1997

A diiodo-substituted 9-anthracenone.

The central ring of the anthrone system in 1,8-diiodo-10-hydroxy-10-(3-methylbut-3-en-1-ynyl)anthrac en-9(10H)-one, C19H12I2O2, has a boat conformation and the two outer rings form a dihedral angle of 41.1 (2) degrees. The I-C bond lengths are 2.094 (4) and 2.083 (4) A. The hydroxyl and carbonyl groups form an intermolecular hydrogen bond having an O...O distance of 2.853 (4) A.

Anthracenes↗
PubMed1997

Micellar Effects on the Reaction S2 O8 2- + Fe(CN)4 (bpy)2-

The reaction Fe(CN)4 (bpy)2- + S2 O8 2- has been studied in aqueous solutions of hexadecyltrimethylammonium chloride (CTAC) and bromide (CTAB), sodium dodecyl sulfate (SDS), dodecyl tricosaoxyethylene glycol ether (Brij35 ), and octylphenol(ethyleneoxide)9.5 ether (Triton X-100). The influence of changes in surfactant concentration on the reaction rate has been investigated. Experimental kinetic data show that the reaction rate is not affected by the presence of SDS, Brij35 , and Triton X-100 in the reaction medium within the surfactant concentration range studied. In CTAC and CTAB solutions the observed first order rate constant is much higher than that obtained in pure water, which can be explained by considering that the two anionic reactants are localized at the positively charged micellar surface. This is also in agreement with the observed decrease in the reaction rate when [cationic surfactant] increases. An increase in the surfactant concentration would provoke a decrease in the local concentration of the reagent in excess, S2 O8 2- ions, at the micellar surface, that is, at the reaction site, which would result in a decrease of the observed pseudo-first-order rate constant. Temperature was maintained at 298.2 K.

Journal Article↗
PubMed1997

Evaluation of the Revised European-American Lymphoma classification confirms the clinical relevance of immunophenotype in 560 cases of aggressive non-Hodgkin's lymphoma.

The Revised European-American Lymphoma (REAL) classification has been criticized for its emphasis on the unproven clinical relevance of immunophenotype. A worse prognosis for peripheral T-cell non-Hodgkin's lymphomas (PTCLs) has been inconsistently reported in part because the definition of PTCL has been imprecise (eg, T-cell-rich B-cell non-Hodgkin's lymphomas [TCRBCLs] have been misdiagnosed as PTCLs in the past) and because its correlation with other known prognostic factors has not been studied by multivariate analysis. We analyzed six protocols from 1984 to 1995 with Working Formulation intermediate grade and immunoblastic lymphomas (exclusive of mantle cell) and selected only those cases in which immunophenotyping was performed and was conclusive. Of a total of 560 evaluable patients, 68 were PTCLs (12%) and the remaining 492 (88%) were B-cell non-Hodgkin's lymphomas, including 16 TCRBCLs (3% of total). The 5-year failure-free survival (FFS) for PTCLs and B-cell large-cell lymphomas (BCLCLs) is 38% and 55%, respectively (P < .0001) and the 5-year overall survival (OS) is 39% and 262%, respectively (P < .001). The M.D. Anderson prognostic tumor score (MDATS) and International Prognostic Index (IPI) for all patients was calculated. With MDATS of less than 3 (good prognosis), the 5-year FFS for PTCL and BCLCL is 56% and 69%, respectively (P = .01), and the 5-year OS is 64% and 77%, respectively (P = .06). With MDATS of greater than 2 (poor prognosis), 5-year FFS for PTCL and BCLCL is 26% and 38%, respectively (P = .03), and the 5-year OS is 24% and 41%, respectively (P = .02). With an IPI of less than 3 (good prognosis), the 5-year FFS for PTCL and BCLCL is 49% and 64%, respectively (P = .001), and the 5-year OS is 55% and 71%, respectively (P = .013). With an IPI greater than 2 (poor prognosis), the 5-year FFS for PTCL and BCLCL is 11% and 35%, respectively (P = .044), and the 5-year OS is 10% and 40%, respectively (P = .011). Multivariate analysis shows that MDATS, IPI, and T-cell phenotype are totally independent and are the most significant predictors of FFS and OS. The 68 PTCLs include 45 PTCLs unspecified, 10 Ki-1 anaplastic (ALCL), 8 angioimmunoblastic, and 5 angiocentric lymphomas. Angiocentrics were usually refractory (1 of 5 remissions only). ALCL rarely relapsed late. We conclude that the immunophenotypic basis of the REAL classification is clinically relevant and that, although other prognostic features also influence outcome, the T-cell phenotype still remains an independent and significant prognostic factor.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Bilateral Candida parapsilosis endophthalmitis.

We describe a patient with bilateral, delayed endophthalmitis who underwent bilateral pars plana vitrectomy, total capsulectomy, intraocular lens exchange, intravitreal injection of amphotericin B, and oral fluconazole therapy. The long-term inflammation resolved, and vitreous cultures from both eyes yielded Candida parapsilosis. Histopathologic examination revealed sequestered yeast forms in the capsular bags.

Aged↗
PubMed1997

Rapid identification of Clostridium botulinum and botulinal toxin in food.

Samples of green beans and mushrooms were inoculated with a toxigenic strain of Clostridium botulinum type A and incubated anaerobically at 37 degrees C. At various time intervals, the seeded food samples were tested for the presence of botulinal toxin and C. botulinum by an agar plating method and an enzyme-linked immunosorbent assay. C. botulinum type A that appeared as lipase-positive colonies on selective agar plates, and its elaborated toxin, were identified in all seeded food samples within 1 to 2 d. This procedure can be adapted for rapid screening of suspected food samples.

Basidiomycota↗
PubMed1997

Body fluid homeostasis and cardiovascular adjustments during submaximal exercise: influence of chewing coca leaves.

The present study was undertaken to determine the haematological and cardiovascular status, at rest and during prolonged (1h) submaximal exercise (approximately 70% of peak oxygen uptake) in a group (n = 12) of chronic coca users after chewing approximately 50 g of coca leaves. The results were compared to those obtained in a group (n = 12) of nonchewers. At rest, coca chewing was accompanied by a significant increase in heart rate [from 60 (SEM 4) TO 76 (SEM 3) beats.min-1], in haematocrit [from 53.2 (SEM 1.2) to 55.6 (SEM 1.1)%] in haemoglobin concentration, and plasma noradrenaline concentration [from 2.8 (SEM 0.4) to 5.0 (SEM 0.5) mumol.l-1]. It was calculated that coca chewing for 1 h resulted in a significant decrease in blood [-4.3 (SEM 2.2)%] and plasma [-8.7 (SEM 1.2)%] volume. During submaximal exercise, coca chewers displayed a significantly higher heart rate and mean arterial blood pressure. The exercise-induced haemoconcentration was blunted in coca chewers compared to nonchewers. It was concluded that the coca-induced fluid shift observed at rest in these coca chewers was not cumulative with that of exercise, and that the hypovolaemia induced by coca chewing at rest compromised circulatory adjustments during exercise.

Adolescent↗
PubMed1997

Influence of gender and endogenous sex steroids on catecholaminergic structures involved in physiological adaptation to hypoxia.

Mechanisms underlying sex-related differences in adaptation to high altitude were investigated by assessing the turnover of dopamine and noradrenaline in structures of the chemoafferent pathway, i.e. carotid body and brainstem noradrenergic cell groups (A1, A5, A6, A2 to which chemosensory fibres project). The influence of gender was assessed in male and female rats reared at an altitude of 3600 m, whereas the influence of endogenous sex hormones was evaluated by castration. Haematocrit, red blood cell count and plasma erythropoietin levels were lower in females than in males (-5%, -15%, -53%, respectively). Dopamine and noradrenaline turnover were higher in female structures (carotid body: +51%; A2: +140%; A1: +54%; A5: +27%). Dopamine and noradrenaline turnover in carotid body and brainstem cell groups were differently affected by castration, i. e. enhanced by orchidectomy (carotid body: +134%; A2: +120%; A1: +69%; A5: +67%) but inhibited by ovariectomy (carotid body: -33%; A2: -92%). Orchidectomy elicited a reduction in haematocrit (-10%), haemoglobin concentration (-8%) and red blood cell count (-24%), whereas haematological status remained unaltered after ovariectomy. Therefore, both gender and endogenous sex steroids may control catecholamine activity differently in structures involved in the chemoafferent pathway, thus providing a neurochemical basis for sex-related differences in adaptation to hypoxia.

Adaptation, Physiological↗
PubMed1997

Differential effects of ventilatory stimulation by sex hormones and almitrine on hypoxic erythrocytosis.

In the absence of pulmonary disease, hypoventilation is considered to be the primary cause of Chronic Mountain Sickness, and there is some reason to believe that chronic administration of respiratory analeptics could be useful for treatment of this disease. The present study was intended to define comparatively the influence of two potent ventilatory stimulants, namely a combination of progesterone and estrogen and the pharmacological agent almitrine, on catecholaminergic structures implicated in the chemoreflex pathway and on hypoxia-induced polycythemia. Three groups of young male rats born and living at high altitude (3 600 m) were examined: untreated animals (n = 25), rats given ovarian steroids (progesterone plus 17beta-estradiol, n = 25) or almitrine (n = 25) for 6 weeks until sacrifice. Ovarian steroids or almitrine had pronounced neurochemical effects on the afferent chemoreflex circuitry. Both treatments inhibited norepinephrine (NE) and dopamine (DA) turnover in the carotid body, but central processing of chemosensory inputs differed between the two respiratory drugs. Ovarian steroids inhibited noradrenergic activity in the projection area of the chemosensory nerve fibers within the caudal portion (A2C) of the nucleus tractus solitarius (NTS). In contrast, almitrine stimulated neurochemical activity of other brainstem noradrenergic cell groups involved in cardiorespiratory control, i.e. , the rostral portion (A2R) of the NTS, the nucleus reticularis lateralis (A1), the nucleus olivaris superior (A5) and the locus ceruleus (A6). Although both treatments increased chemoreflex drive and ventilation, only sex hormones decreased erythropoietin (EPO) levels and the degree of polycythemia. These results suggest that stimulation of ventilation through activation of peripheral arterial chemoreceptors activation alone is not sufficient for reducing EPO levels and polycythemia. The better efficiency of female sex hormone treatment as compared to almitrine could be related either to the central effects of progesterone and estrogen and/or to the impact of these hormones on erythropoiesis at the kidney/bone marrow level.

Almitrine↗
PubMed1997

Cystic pyeloureteritis: review of 34 cases. Radiologic aspects and differential diagnosis.

OBJECTIVES: To refine the clinical and radiologic description of an unusual benign disease, cystic pyeloureteritis (CPU), consisting of the appearance of suburothelial cysts that raise the mucosa layer of the urothelium. We also studied its relationship with various types of inflammation, including chronic infection, that may be the stimulus for the appearance of CPU. METHODS: We compiled 34 cases of CPU covering the period 1976 to 1994, analyzing the clinical manifestations, diagnostic procedures, differential diagnosis, and evolution. RESULTS: There are no specific symptoms associated with the presence of cysts. The average age of the patients was 59 years (range 30 to 77). Urinary tract infection was detected in 18 (53%). The pyeloureteritis was unilateral in 27 (79%) and bilateral in 7 (21%) of the patients. The location of the cysts was as follows: 1 pyelic (3%); 6 pyeloureteral (18%); and 27 (79%) ureteral. Resolution of the radiologic alterations depends on the resolution of the associated pathology: infections, lithiasis, and obstruction. CONCLUSIONS: We conclude that CPU is a benign pathology with indolent evolution and variable duration; it is not associated with sequelae. Diagnosis is made on the basis of radiologic findings, mainly intravenous urography; in view of the minor entity of the pathology, biopsy is not advisable if the radiologic findings are conclusive.

Adult↗
PubMed1997

Enzyme changes in zymogen granules and in pancreatic secretion throughout long-term CCK treatment.

Pancreatic enzyme storage and secretion were studied in rats treated twice daily with s.c. injections (5 micrograms/kg) of CCK-8 for 3, 7, and 15 days. Isolated zymogen granules were analyzed by flow cytometry to determine their FSC (forward scatter), SSC (side scatter), and amylase and trypsinogen contents. DNA content, pancreatic weight, and both basal and stimulated pancreatic secretion under i.v. CCK infusion (1.25 micrograms/kg/h) were also studies. Two subsets of zymogen granules were identified by flow cytometry in both control and CCK-treated rats on the basis of FSC and SSC parameters: Z1 (smaller and less complex) and Z2. Both subsets displayed a high degree of heterogeneity with respect to their enzyme content per zymogen granule. During the first 7 days of CCK treatment, hyperplasia and hypertrophy developed in the rats together with changes in the zymogen granules, reflected by a significantly decreased FSC, and increased SSC, and an increase in the mean trypsinogen/amylase ratio per granule. A rise in pancreatic enzyme secretion, especially of trypsin, was observed. After 15 days of CCK administration, a simultaneous decrease in amylase content and increase in trypsinogen content per zymogen granule was observed. A desensitization of the pancreas to CCK happened after 15 days of CCK administration, reflected by a reduction of all the pancreatic functions that had been increased at shorter CCK administration periods. Nevertheless, trypsinogen appeared resistant to desensitization because its secretion significantly increased in response to an i.v. infusion of CCK. CCK treatment displayed a differential packaging of the enzymes in individual zymogen granules; the trypsinogen/amylase ration was significantly higher in Z2 zymogen granules than in Z1 subset throughout the treatment.

Amylases↗
PubMed1997

Genomic DNA repeat from Leishmania (Viannia) braziliensis (Venezuelan strain) containing simple repeats and microsatellites.

In this paper the Leishmania (Viannia) braziliensis complex is defined as containing all species of the actual subgenus Viannia. Organisms of the L. (V) braziliensis complex are the causative agents of localized human cutaneous and mucocutaneous leishmaniasis in South America, much of Central America and some ares of North America. In our search for better species and subspecies diagnostic probes we focused our research on repetitive DNA, since it provides a greater number of target sites for hybridization. In this work we report the isolation and sequencing of a 1.8 kb DNA region, LbJ38, which is probably tandemly repeated or dispersed at least 4 times along one chromosome and is naturally present in L. (V) braziliensis genomic DNA. This region contains microsatellites and simple repeat DNA sequences and was isolated by screening a genomic DNA cosmid library with complex- and species-specific probes. No homology was found with other Leishmania microsatellite or repetitive DNA. The utility of this repetitive sequence and primers derived from it in the identification of L. (V) braziliensis is demonstrated. As far as we are aware, this is the first report of sequence characterized repetitive microsatellite and GC rich simple repeat DNA from the nuclear genome of New World Leishmania.

Animals↗
PubMed1997

L-hydroxytryptophan amplifies pulsatile secretion of LH in the follicular phase of normal women.

OBJECTIVES: The hypothalamus possesses serotoninergic fibres which arise from neuronal cell bodies located in the raphe nuclei and have synapse on GnRH-secreting neurones. Hitherto, no firm evidence has been produced to support a role for serotoninergic control of LH in humans. Our first objective was to investigate whether pulsatile administration of L-5-hydroxytryptophan--the immediate precursor of serotonin--affects pulsatile LH secretion in the medium-late follicular phase of normal women. Since the results of the first experiment suggest that L-5-hydroxytryptophan amplifies LH release, our second objective was to investigate whether, in the absence of GnRH, L-5-hydroxytryptophan can release LH. This was done by studying LH response in patients with hypogonadotrophic hypogonadism of hypothalamic origin. PATIENTS: Twenty-two normal women (18-25 years old) and 8 patients with hypogonadotrophic hypogonadism (2 men with Kallmann's syndrome and 6 women with anorexia nervosa). DESIGN: Serum LH levels in the 22 subjects (reference population) were monitored at 10-minute intervals over an 8-hour period (1000-1800h) during medium-late follicular phase. In 7 of these subjects, serum LH levels were monitored in their next medium-late follicular phase while L-5-hydroxytryptophan was administered at hourly intervals from 1000 to 1800 h; the peripheral conversion of L-5-hydroxytryptophan to serotonin was inhibited by 150 mg of benserazide at 0930 and 1430h. To investigate whether, in the absence of GnRH, L-5-hydroxytryptophan can release LH, two patients with Kallmann's syndrome were monitored over a 7-hour period and 6 patients with anorexia nervosa over a 9-hour period. After a 2-5 hour control period the subjects received 150 mg of benserazide, and pulsatile L-5-hydroxytryptophan (every 30 minutes in the Kallmann's patients and every 45 minutes in the subjects with anorexia nervosa). MEASUREMENTS: LH pulses were identified and analysed according to number, amplitude, interpulse interval and pulse duration. RESULTS: In the normal women, L-5-hydroxytryptophan increased pulse amplitude (mean +/- SD; 3.02 +/- 1.42 IU/l vs. 1.75 +/- 0.98 IU/l before L-5-hydroxytryptophan and 1.90 +/- 1.04 IU/l in the reference population; P < 0.01 in both cases), but had no significant effects on pulse duration, interpulse interval or number of pulses. L-5-hydroxytryptophan had no effect on LH in patients with Kallmann's syndrome. In the anorexia nervosa group, the mean serum LH level increased significantly after L-5-hydroxytryptophan (3.90 +/- 2.46 IU/l vs. 3.06 +/- 1.23 IU/l, P < 0.001) but, as in Kallmann's patients, the three women in this group without residual LH pulsatility did not respond to L-5-hydroxytryptophan. CONCLUSION: Pulsatile administration of L-5-hydroxytryptophan increases LH pulse amplitude in the follicular phase of normal women. In the absence of GnRH, L-5-hydroxytryptophan does not stimulate pituitary LH secretion.

5-Hydroxytryptophan↗
PubMed1997

Abdominal injuries without hemoperitoneum: a potential limitation of focused abdominal sonography for trauma (FAST)

BACKGROUND: Focused abdominal sonography for trauma (FAST) relies on hemoperitoneum to identify patients with injury. Blunt trauma victims (BTVs) with abdominal injury, but without hemoperitoneum, on admission are at risk for missed injury. METHODS: Clinical, radiologic, and FAST data were collected prospectively on BTVs over a 12-month period. All patients with FAST-negative for hemoperitoneum were further analyzed. Examination findings and associated injuries were evaluated for association with abdominal lesions. RESULTS: Of 772 BTVs undergoing FAST, 52 (7%) had abdominal injury. Fifteen of 52 (29%) had no hemoperitoneum by admission computed tomographic scan, and all had FAST interpreted as negative. Four patients with splenic injury underwent laparotomy. Six other patients with splenic injury and five patients with hepatic injury were managed nonoperatively. Clinical risk factors significantly associated with abdominal injury in BTVs without hemoperitoneum include: abrasion, contusion, pain, or tenderness in the lower chest or upper abdomen; pulmonary contusion; lower rib fractures; hemo- or pneumothorax; hematuria; pelvic fracture; and thoracolumbar spine fracture. CONCLUSIONS: Up to 29% of abdominal injuries may be missed if BTVs are evaluated with admission FAST as the sole diagnostic tool. Consideration of examination findings and associated injuries should reduce the risk of missed abdominal injury in BTVs with negative FAST results.

Abdominal Injuries↗