Search PubMed⌕ Search

Biomedical subjects

J Nieto

Publications and source records attributed to J Nieto.

At least 19 recordsLinked to original sources
PubMed1998

Identification of one tachykinin- and two kinin-related peptides in the brain of the white shrimp, Penaeus vannamei.

This paper reports the purification of three myotropic neuropeptides from the white shrimp Penaeus vannamei. The central nervous systems of 3500 shrimps were extracted in an acidified solvent, after which four to five HPLC column systems were used to obtain pure peptides. A cockroach hindgut muscle contraction bioassay was used to monitor all collected fractions. The pure peptides were submitted to Edman degradation based automated microsequencing. Mass spectrometry and chemical synthesis confirmed the sequences. Ala-Pro-Ser-Gly-Phe-Leu-Gly-Met-Arg-NH2 (Pev-tachykinin, 934.1 Da) belongs to the tachykinin family with identified members in all vertebrate classes and some invertebrate classes: arthropods, annelids and molluscs. A very specific Pev-tachykinin antiserum was developed, which labels 4 neurosecretory cells in the brain. Ala-Ser-Phe-Ser-Pro-Trp-Gly-NH2 (Pev-kinin 1, 749.8 Da) and Asp-Phe-Ser-Ala-Trp-Ala-NH2 (Pev-kinin 2, 694.7 Da) are the first crustacean kinins. Pev-kinin 2 is the first kinin with a Trp-Ala-NH2 instead of a kinin-typical Trp-Gly-NH2 carboxyterminus.

Animals↗
PubMed1998

Morphologic changes and xanthine oxidase activity in the equine jejunum during low flow ischemia and reperfusion.

OBJECTIVE: To determine whether xanthine oxidase and dehydrogenase activities are altered during low flow ischemia and reperfusion of the small intestine of horses. ANIMALS: 5 clinically normal horses without histories of abdominal problems. PROCEDURE: With the horse under general anesthesia, a laparotomy was performed and blood flow to a segment of the distal jejunum was reduced to 20% of baseline for 120 minutes and was then reperfused for 120 minutes. Biopsy specimens were obtained before, during, and after ischemia for determination of xanthine oxidase and dehydrogenase activities, and for histologic and morphometric analyses. RESULTS: Percentage of xanthine oxidase activity (as a percentage of xanthine oxidase and dehydrogenase activity) was not altered during ischemia and reperfusion. An inflammatory response developed and progressed during ischemia and reperfusion. Mucosal lesions increased in severity after ischemia and reperfusion. Mucosal surface area and volume decreased during ischemia and continued to decrease during reperfusion. Submucosal volume increased slightly during ischemia, and continued to increase during reperfusion. CONCLUSIONS AND CLINICAL RELEVANCE: Evidence for conversion of xanthine dehydrogenase to xanthine oxidase during ischemia was not found. Factors other than production of reactive oxygen metabolites may be responsible for progressive epithelial loss, decrease in mucosal surface area and volume, and increase in submucosal volume observed in this study. Other methods of determining xanthine oxidase activity that detect the enzyme in sloughed epithelial cells should be used to better define the importance of this pathway in jejunal reperfusion injury in horses.

Animals↗
PubMed1997

Tertiary hyperparathyroidism after renal transplantation.

Tertiary hyperparathyroidism is considered as an autonomous proliferation state of the parathyroid glands with biological hyperfunction resistant to calcium/vitamin suppressor therapy. This phenomenon is thought to be secondary to monoclonal inactivation of tumoral growth suppression factor located on chromosome 11. Three patients, 13, 15, and 22 years of age, with chronic renal insufficiency of long evolution who presented with tertiary hyperparathyroidism following renal transplantation are described. The three patients underwent subtotal parathyroidectomy with consequent normalization of biochemical parameters of phospho-calcium metabolism in the first few weeks post surgery. Pathologic study showed adenoma in the affected glands with hyperplasia of the rest. We believe that in patients with long-term renal insufficiency an aggressive treatment, either medical or surgical, of secondary hyperparathyroidism which is continued after renal transplantation may be useful in preventing the development of tertiary hyperparathyroidism.

Adenoma↗
PubMed1997

Age-related differences in norfloxacin pharmacokinetic behaviour following intravenous and oral administration in sheep.

The pharmacokinetics of norfloxacin after intravenous (i.v.) and oral (PO) administration in lambs (n = 5) and adult sheep (n = 5) were studied. After i.v. administration (10 mg.kg-1) plasma concentrations were best fitted by a three-compartment open model in both age groups. Distribution volumes were significantly larger in lambs (approximate 4.0 fold difference between 4 week old and adult sheep). There was no significant difference (p < 0.05) between the groups in terms of elimination halflife but plasma clearance was significantly higher in lambs. Norfloxacin was poorly absorbed after oral administration (60 mg.kg-1) in sheep (F = 4.04%). Mean oral bioavailability was 73.51% in lambs (30 mg.kg-1). Norfloxacin elimination was faster in lambs after oral administration. MRTt was significantly prolonged in both age groups when compared with the respective data for i.v. administration.

Absorption↗
PubMed1997

The prevalence and severity of white matter lesions, their relationship with age, ethnicity, gender, and cardiovascular disease risk factors: the ARIC Study.

White matter lesions (WMLs) detected by cerebral magnetic resonance imaging (MRI) are putatively a consequence of cerebral hypoperfusion or ischemia. We investigated the prevalence, severity and correlates of WMLs in a population-based sample of 1,920 African-American and European-American men and women aged 55-72 years, during the second follow-up examination of the Atherosclerosis Risk in Communities Study. The spin density images from 1.5-tesla MRI scans were used to define WMLs using a 0-9 scale with 0 for normal and 9 for most severe WMLs. Age was positively associated with the prevalence (percent) and severity of WMLs. African-Americans had lower overall prevalence of WMLs, but a higher prevalence of relatively more severe WMLs, than European-Americans. After adjusting for age, sex, and ethnicity, WMLs were significantly associated with smoking, lower education, hypertension, systolic blood pressure, and pulse pressure, and weakly associated with diastolic blood pressure. The associations of smoking, alcohol intake, systolic and diastolic blood pressure, pulse, pressure, and hypertension were stronger in African-Americans than in European-Americans (p < 0.15 for interactions by ethnicity). This population-based MRI study documents significant relationships between several cardiovascular disease risk factors and WMLs. The findings suggest that such factors play a role in the pathogenesis of WMLs, an elements linked to hypoperfusion and/or fluid accumulation, which presumably lead to WMLs. African-Americans exhibited both a higher proportion of normal white matter and a higher proportion of relatively more severe WMLs than European-Americans.

Age Factors↗
PubMed1996

Characterization of Spanish Trichinella isolates by random amplified polymorphic DNA (RAPD).

The random amplified polymorphic DNA (RAPD) assay was used to find molecular markers able to distinguish Trichinella spiralis from T. britovi, the two recognized Spanish Trichinella species. Fourteen Spanish Trichinella isolates, as well as reference Trichinella isolates representing the five species T. spiralis (T1), T. nativa (T2), T. britovi (T3), T. pseudospiralis (T4) and T. nelsoni (T7) and the three other taxa Trichinella T5, Trichinella T6 and Trichinella T8 of the genus, were characterized by RAPD using both purified and crude DNAs from infective muscle larvae (ML) and seven arbitrary primers. Three primers yielded diagnostic RAPD markers for the Spanish T. spiralis and T. britovi isolates as well as for the Trichinella reference isolates analysed, and in the case of crude DNAs the results were obtained in few hours. In addition, the species-specificity of the diagnostic RAPD markers from Spanish Trichinella isolates was studied by cross-hybridization assays. These assays confirmed that the selected diagnostic DNA fragments were not species-specific, but showed potential differences in the copy number among the examined Trichinella genetic clusters.

Animals↗
PubMed1996

Effects of U-74389G, a novel 21-aminosteroid, on small intestinal ischemia and reperfusion injury in horses.

OBJECTIVE: To determine the effects of the 21-aminosteroid, U-74389G, on reperfusion of the equine jejunum, using total (TVO) and partial (PVO) vascular occlusion during the ischemic period. DESIGN: TVO: 16 healthy horses were randomly allotted to 3 groups-4 horses received the vehicle alone, 6 horses received a low dosage (3 mg/kg o body weight), and 6 horses a high dosage (10 mg/kg) of U-7438G. PVO: 10 healthy horses were randomly allotted to 2 groups--5 horses received the vehicle alone, and 5 horses received the low dosage (3 mg/kg) of U-74389G. PROCEDURES: TVO was induced for 1 hour followed by 2 hours of reperfusion. During PVO, blood flow was reduced to 20% of baseline for 2 hours, followed by 2 hours of reperfusion. For both models, either the vehicle alone or the drug was given 15 minutes prior to reperfusion. Samples were obtained before, during, and after ischemia for determination of myeloperoxidase (MPO) activity, malondealdehyde (MDA) concentration, concentration of conjugated dienes (PVO experiment only), and morphometric analysis. RESULTS: TVO: tissue concentration of MDA and MPO activity were not altered in any group by ischemia or reperfusion. During ischemia, mucosal volume and surface area were reduced. After reperfusion, no further reduction occurred. After initial decrease in submucosal volume during ischemia, there was a significant increase after reperfusion in the vehicle-only group (P < 0.05). PVO: there were no alterations in the concentration of either MDA or conjugated dienes. There was significant increase in the activity of MPO during ischemia and reperfusion (P < 0.05). These effects were similar for the vehicle-only and drug groups. During ischemia, there was a significant decrease in mucosal surface area and volume (P < 0.05), that was continued during reperfusion for the vehicle-only (P < 0.05). Submucosal volume increased during ischemia and reperfusion. CONCLUSIONS AND CLINICAL RELEVANCE: Reduced blood flow during ischemia (PVO group) caused continued loss in mucosal volume and surface area during reperfusion. At the dosage given, the 21-aminosteroid, U-74389G, was not effective in preventing continued reduction in mucosal volume and surface area after restoration of blood supply in the horses subjected to reduced blood flow.

Animals↗
PubMed1994

A laboratory model of canine leishmaniasis: the inoculation of dogs with Leishmania infantum promastigotes from midguts of experimentally infected phlebotomine sandflies.

Twenty-five dogs (beagles) were infected with Leishmania infantum by the intradermal inoculation of an estimated 5-8,000 metacyclic promastigotes harvested from the midguts of 320 experimentally infected P. perniciosus. Details are given of the methods of infecting the flies and harvesting the parasites. All dogs developed small, self-healing chancres at the sites of inoculation. Parasites were isolated from lymph nodes, bone marrow or spleen of 21 dogs, 12 of which developed signs of disease and raised IFAT litres to Leishmania. Nine of the 21 remained healthy over a five-year observation period. Six of the nine were shown to have a cell mediated immune response to Leishmania. No parasites were isolated from four of the 25 dogs, two of which had a demonstrable cell mediated immunity and another had low transitory IFAT titres. The fourth had chancres at the sites of inoculation. The results show that dogs can be readily infected with promastigotes from the midguts of sandflies. However, a high proportion develop a cell mediated immunity and show on signs of disease. It is suggested that serological surveys of dogs for canine leishmaniasis reveal neither the true prevalence of infection nor the intensity of transmission. The efficacy of controlling human visceral leishmaniasis caused by L. infantum by destroying seropositive dogs is questioned.

Animals↗
PubMed1994

Canine leishmaniasis: clinical, parasitological and entomological follow-up after chemotherapy.

Six naturally infected dogs [two with no signs of leishmaniasis ('asymptomatic'), two with a few signs ('oligosymptomatic') and two with many signs ('polysymptomatic')] were studied before and after chemotherapy. Another two, non-infected dogs were kept as controls. The dogs were studied clinically, haematologically and parasitologically five times over 11 months and their infectivity to sandflies was evaluated before and after the treatment. The 'asymptomatic' dogs were as infective to sandflies as the 'symptomatic' before treatment but all dogs were un-infective for at least a few months following chemotherapy. Treatment led to a temporary improvement in the clinical and biochemical condition of most of the dogs, the symptomatic dogs becoming asymptomatic, but parasitological cure was uncommon after 10 months' follow-up. There was often no correlation between clinical condition, parasitological condition and infectivity to sandflies. Some dogs from both the 'asymptomatic' and 'symptomatic' groups became infective to sandflies several months post-treatment.

Animals↗
PubMed1994

Successful therapy for cerebral phaeohyphomycosis due to Dactylaria gallopava in a liver transplant recipient.

A 68-year-old liver transplant recipient who was being treated with FK 506 and immunosuppressive steroid therapy was admitted to our medical center because of a tonic-clonic seizure. Computed tomography of the head revealed multiple discrete cerebral abscesses, and culture of fluid drained intraoperatively yielded a dematiaceous fungus. The isolate was susceptible to amphotericin B and itraconazole but was resistant to flucytosine and fluconazole. The patient was successfully treated with a prolonged course of amphotericin B colloidal dispersion and itraconazole, as evidenced by both clinical and radiographic resolution of disease over a 2-year follow-up.

Aged↗
PubMed1994

[Autoimmune hemolytic anemia associated with ulcerative colitis arising after colectomy].

Autoimmune hemolytic anemia is a rare, although not exceptional, complication of ulcerative colitis. This report presents a case of this association, which is noteworthy in that the hematologic picture appeared immediately after colectomy was performed due to colonic perforation. The features of the only three reported cases in which anemia developed after colectomy are reviewed, and the role of this surgical technique in the treatment of hemolytic anemia associated with ulcerative colitis is discussed. Although colectomy does not protect patients with ulcerative colitis from the onset of hemolytic anemia, we consider that proctocolectomy should be included among the therapeutic alternatives when this association is present, especially in the case of refractory colitis.

Adult↗
PubMed1993

Renal calcifications in patients with autosomal recessive polycystic kidney disease: prevalence and cause.

OBJECTIVE: We investigated the prevalence of renal calcifications in children with autosomal recessive polycystic kidney disease and studied the metabolic changes that could cause this complication. SUBJECTS AND METHODS: Nine patients with known autosomal recessive polycystic kidney disease were examined with sonography and CT and screened for biochemical evidence of metabolic causes of nephrocalcinosis. RESULTS: CT showed bilateral renal calcifications in seven of the nine patients. The two patients without renal calcifications were less than 1 year old. Four patients had only a few calcifications and three patients had many. The severity of the renal calcifications correlated with the degree of kidney failure. All patients with kidney failure were found to have urine acidification defects. Hypocitraturia was present in all patients. CONCLUSION: Our results show that renal calcifications are common in older children with autosomal recessive polycystic kidney disease. Hypocitraturia and the urine acidification defect resulting from kidney failure are the leading factors in the pathogenesis of the calcifications.

Adolescent↗
PubMed1992

Effect of cyclosporin A on proteinuria in patients with Alport's syndrome.

Eight patients with Alport's syndrome and massive proteinuria (129 +/- 60.57 mg/m2 per hour) were treated with cyclosporin A (CyA) for 8 months. The average dose of CyA administered to all patients was 4.21 +/- 0.26 mg/kg per day and blood CyA levels of 63.4 +/- 4.1 ng/ml were attained. In five patients, proteinuria abated during the 3rd week of treatment. In the remaining three, all of whom had low creatinine clearance (82.0, 46.0 and 43.2 ml/min per 1.73 m2 respectively), proteinuria persisted but at levels lower than before treatment: 32.5 +/- 15.9 mg/m2 per hour versus 183.3 +/- 29.7 mg/m2 per hour. No permanent decrease in creatinine clearance was observed in any of these patients throughout treatment. In those patients in whom proteinuria abated, it reappeared 2 weeks after discontinuation of CyA treatment. We observed no significant increases in angiotensin II plasma levels in our patients during CyA administration. Although we have shown that CyA will reduce massive proteinuria in patients with Alport's syndrome, we cannot yet recommend its use as a therapeutic measure.

Adolescent↗