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Biomedical subjects

J Valenzuela

Publications and source records attributed to J Valenzuela.

At least 19 recordsLinked to original sources
PubMed1998

Development of a natural model of cutaneous leishmaniasis: powerful effects of vector saliva and saliva preexposure on the long-term outcome of Leishmania major infection in the mouse ear dermis.

We have developed a model of cutaneous leishmaniasis due to Leishmania major that seeks to mimic the natural conditions of infection. 1,000 metacyclic promastigotes were coinoculated with a salivary gland sonicate (SGS) obtained from a natural vector, Phlebotomus papatasii, into the ear dermis of naive mice or of mice preexposed to SGS. The studies reveal a dramatic exacerbating effect of SGS on lesion development in the dermal site, and a complete abrogation of this effect in mice preexposed to salivary components. In both BALB/c and C57Bl/6 (B/6) mice, the dermal lesions appeared earlier, were more destructive, and contained greater numbers of parasites after infection in the presence of SGS. Furthermore, coinoculation of SGS converted B/6 mice into a nonhealing phenotype. No effect of SGS was seen in either IL-4- deficient or in SCID mice. Disease exacerbation in both BALB/c and B/6 mice was associated with an early (6 h) increase in the frequency of epidermal cells producing type 2 cytokines. SGS did not elicit type 2 cytokines in the epidermis of mice previously injected with SGS. These mice made antisaliva antibodies that were able to neutralize the ability of SGS to enhance infection and to elicit IL-4 and IL-5 responses in the epidermis. These results are the first to suggest that for individuals at risk of vector-borne infections, history of exposure to vector saliva might influence the outcome of exposure to transmitted parasites.

Animals↗
PubMed1997

Involvement of calcium in the cardiac depressant actions of a garlic dialysate.

In order to elucidate a possible role for calcium on the negative cardiotropic effects of a garlic (Allium sativum L., Liliaceae) dialysate in rat atria we studied: (a) the effects of our extract 15 min after preincubation with high and low concentrations of extracellular calcium ([Ca2+]o) on left and right activity of rat atria. The negative inotropism of garlic dialysate increased with calcium 0.75 mM; in contrast, high level of calcium (4.5 mM) induced a significant reduction of this depressant effect. None of these treatments modified the negative chronotropism of garlic; (b) nifedipine (10(-9) to 10(-7) M, verapamil (10(-9) to 10(-7) M) and diltiazem (10(-9) to 10(-7) M) induced a concentration-dependent synergism of the log concentration-effect of garlic dialysate on left atria. Verapamil and diltiazem (10(-7)M), but not nifedipine increased the inhibitory chronotropism of garlic in right atria; (c) negative inotropic and chronotropic effects demonstrated by nifedipine (1 x 10(-10) to 1.1 x 10(-6) M) were antagonized as expected by preincubation with Bay K-8644. Depressant actions of garlic were not modified with this pretreatment. These results suggest that the negative inotropic effect of our garlic dialysate is related to [Ca2+]o availability. It is possible that a restriction of intracellular calcium contributes to this effect. However, the negative chronotropic effect of garlic is scarcely affected by these modifications.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1997

Helicobacter pylori infection in Chile.

This article summarizes studies designed to evaluate the role of Helicobacter pylori infection in Chile, described in 21 reports from nine centers in various Chilean regions published between 1985 and 1995. According to their data, H. pylori infection is quite frequent among patients with a variety of gastric conditions, including adults (43%-92%) and children (6%-100%). Levels of specific IgG antibodies to H. pylori are also elevated among patients with duodenal ulcers (100%) and gastritis (86%) as well as asymptomatic adults (75%). Combination therapy with three (but not two) drugs has been proved effective, with clinical improvement, ulcer cure, and H. pylori eradication occurring in well-controlled studies. Available evidence suggests that antibiotic resistance is not a major problem in treatment. The H. pylori reinfection rate is low (4.2% per year), suggesting that combination therapy with three drugs constitutes a cost-effective alternative for treating colonized symptomatic patients. Concurrent preliminary studies revealed that antibodies to VacA but not CagA proteins correlate with disease severity in Chilean patients. It can be concluded that local research assists local administrators of health resources to implement adequate policies to prevent, control, and treat H. pylori-related pathologies.

Chile↗
PubMed1997

Accidental radiation injury to the hand: anatomical and physiological considerations.

A case study describing an accident in Mexico caused by failure to de-energize an x-ray spectrometer prior to repair is presented. The evolution, medical management, and outcome of the radiation injury to the hand are briefly reviewed. A discussion follows, with radiation injury and thermal burns compared and contrasted. The anatomy and physiology of thick skin and the vascular system of the hand are reviewed so that the reader will have a better understanding of the role of vascular injury in the pathological process that leads to tissue atrophy and radiation necrosis. Hyperbaric oxygen therapy, sympathectomy, and other techniques for improving circulation in involved areas are reviewed.

Adult↗
PubMed1995

Multicenter trial of octreotide in patients with refractory acquired immunodeficiency syndrome-associated diarrhea.

BACKGROUND/AIMS: Diarrhea is a significant problem in patients with acquired immunodeficiency syndrome (AIDS). The aim of this study was to determine octreotide effectiveness in refractory AIDS-associated diarrhea. METHODS: In a 3-week protocol, 129 patients with a stool weight of > 500 g/day despite standard antidiarrheal therapy were randomized to receive octreotide or placebo (3:2 ratio). Octreotide dose was increased 100 micrograms weekly to a maximum of 300 micrograms three times a day based on weekly 72-hour stool collections. Subsequently, patients received open-label octreotide at doses of up to 500 micrograms three times a day. RESULTS: A 30% decrease in stool weight defined response. After 3 weeks, 48% of octreotide- and 39% of placebo-treated patients had responded (P = 0.43). At 300 micrograms three times a day, 50% of octreotide- and 30.1% of placebo-treated patients responded (P = 0.12). At a baseline stool weight of 1000-2000 g/day, 57% of octreotide- and 25% of placebo-treated patients responded (P = 0.06). Response rates based on CD4 counts, diarrhea duration, body weight, human immunodeficiency virus risk factor, and presence or absence of pathogens showed no benefit of octreotide. Adverse events were more frequent in the octreotide-treated group. CONCLUSION: In the doses studied, octreotide was not more effective than placebo in patients with refractory AIDS-associated diarrhea. This lack of effectiveness may be attributable to inadequate sample size, doses, and duration of study treatment.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Anti-arrhythmic profile of a garlic dialysate assayed in dogs and isolated atrial preparations.

The effects of garlic (Allium sativum L., Liliaceae) dialysate were studied on arrhythmias induced in anaesthetized dogs and on isolated left rat atria. Garlic dialysate suppressed premature ventricular contractions (PVC) and ventricular tachycardia (VT) in ouabain-intoxicated dogs as well as the ectopic rhythms induced by isoprenaline (10(-6) M) and aconitine (10(-8) M) on electrically driven left rat atria. The effective refractory period (ERP) and the sinus node recovery time (SNRT) of isolated rat atria were prolonged in a dose-dependent manner by the administration of this extract. Garlic dialysate decreased the positive inotropic and chronotropic effects of isoprenaline in a concentration-dependent manner. These last effects were increased by propranolol. The results suggest that garlic dialysate has a significant antiarrhythmic effect in both ventricular and supraventricular arrhythmias.

Aconitine↗
PubMed1993

Gallbladder dysfunction in diabetes mellitus.

To further elucidate the mechanism of impaired gallbladder emptying in diabetics with and without neuropathy, gallbladder function was assessed by ultrasonography following a medium-chain triglyceride (lipomul, 1.5 mg/kg) infusion into the duodenum and compared to that during intravenous infusion of cholecystokinin in diabetic women. Results were compared with five healthy control women. Mean (+/- SD) maximal percent gallbladder volume in diabetics following lipomul was reduced to 49 +/- 8% and after intravenous cholecystokinin to 47 +/- 9%, which was less than those in controls, 21 +/- 9% and 24 +/- 6%, respectively, but not significantly different. Further analysis of gallbladder emptying to lipomul differentiated two subgroups of diabetics: one subgroup (N = 5) had emptying comparable to controls (responders), while the other (N = 5) had very modest emptying (nonresponders). Two of the patients in the latter group had normal gallbladder emptying during exogenous cholecystokinin and their response would be compatible with visceral neuropathy. Blood levels of cholecystokinin, measured by bioassay, following lipomul and exogenous cholecystokinin were similar in controls and diabetics. Presence of diabetic neuropathy did not correlate with impaired gallbladder emptying. Follow up at 6 and 12 months of the three nonresponder diabetics revealed that no gallstones had developed and that two of them became responders to exogenous cholecystokinin.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Clinical characteristics of patients with multiple or giant peptic ulcers].

The incidence and clinical characteristics of multiple or giant ulcers (over 20 mm for duodenal ulcer or 25 mm for gastric ulcer) was evaluated among 1434 patients with peptic ulcers. For gastric ulcers, multiple and giant lesions were found in 27% and 14% of patients respectively. Among duodenal ulcers the corresponding figure were 16% and 2.4%. Patients with triple gastric ulcers have a greater incidence of massive bleeding. Patients with triple duodenal ulcers are older, have more massive bleeding and have a greater incidence of gastric retention and hypersecretion when compared to patients with single or double duodenal ulcers. Giant gastric ulcer was associated to a shorter history and more massive bleeding; giant duodenal ulcer was associated to older age, more massive bleeding and gastric retention, when compared to patients with common size ulcers.

Adult↗
PubMed1991

[Aseptic meningitis following spinal anesthesia. Report of a case].

Aseptic meningitis after lumbar puncture and spinal anesthesia is a rare but serious complication, whose acute onset and clinical symptoms mimic septic meningitis. A 33 year old woman presented this complication 5 h after an uneventful cesarean section under subarachnoid blockade. Though lumbar puncture revealed pleocytosis with negative Gram stains and cultures, she was treated with antibiotics and made a full recovery. The clinical picture, differential diagnosis and value of early lumbar puncture are discussed. The successful use of midazolam to treat psychomotor agitation in this patient is also reported.

Adult↗
PubMed1989

[Prevalence of esophageal and gastrointestinal symptoms in Chilean adults].

We surveyed 300 randomly selected presumable healthy adults for previously defined gastrointestinal and esophageal symptoms. Heartburn was the most common symptom, more frequent in females than in males (p less than 0.01). An association of esophageal symptoms to heartburn but not to smoking habit was found. Constipation was frequent in females and diarrhea in males. We conclude that esophageal symptoms are frequent in presumable healthy individuals.

Adult↗
PubMed1989

[Scintigraphic method for the study of painful shoulder syndrome: differential count].

Pain may be present in different sites in patients with a painful shoulder syndrome. We compared (scintigraphy) 56 patients with unilateral painful shoulder syndrome and 26 controls. A differential count index (DCI) was used to evaluate painful sites. Values (mean +/- SD) obtained for patients and controls at different sites were: acromioclavicular joint 1.53 +/- 0.33 vs 1.09 +/- 0.08 (p less than 0.005); * 1.30 +/- 0.39 vs 1.07 +/- 0.07 (p less than 0.01); scapular insertion of deltoid muscle 1.61 +/- 0.40 vs 1.10 +/- 0.10 (p less than 0.005); scapular insertion of trapezius muscle 1.31 +/- 0.21 vs 1.08 +/- 0.06 (p less than 0.005). Average number of painful sites for patients 40 years and older was 2.24 vs 1.58 for younger patients (p less than 0.005). Sensitivity and specificity for pain in the various sites was: * 50% and 90%: acromioclavicular joint 85% and 88%; scapular insertion of deltoid muscle 83 and 90%; and scapular insertion of trapezius muscle 71 and 80%, respectively.

Adult↗
PubMed1989

[Unusual sarcomas of the breast. Report of 3 cases].

Non phylloides sarcomas of the breast are infrequent malignant tumors that can be identified only at histologic examination since clinical presentation may not differ from the more frequent phylloides type. In addition to fibrosarcoma, leiomyosarcoma, rhabdomyosarcoma, angiosarcoma and liposarcoma, the stromal sarcoma of the breast has been recently identified. We report 3 such cases with heterologous components of osteosarcoma, chondrosarcoma and liposarcoma. A third case with an anti-sarcoma appearing post radiotherapy for breast carcinoma is also reported.

Adult↗
PubMed1987

Epidemiology of strongyles in ponies in Ontario.

The transmission of strongyles among 54 Shetland-cross mature ponies was examined from May 30 to November 22, 1983 when the ponies were on pasture and over the ensuing winter when they were in loose housing. Fecal and pasture herbage samples were taken fortnightly through the pasture season and periodically thereafter. Three foals born and reared on pasture were weaned and removed from pasture, two in early August and one in mid-September, and housed for a period before necropsy. Daily maximum and minimum air temperature and total precipitation were recorded. The mean fecal strongyle egg count was highest in the spring and early summer and lowest over the winter. Few larvae were found on the herbage in late May and their numbers were near zero by the third week in June. Subsequently, the numbers increased, were highest from late August through to mid-October and then declined and were low over the winter. Few strongyles were found in two foals removed earlier in the season, and many in the one later. The transmission of strongyles appeared to occur, therefore, principally from mid-summer to mid-fall.

Animals↗
PubMed1983

Recurrent ulcer after successful treatment with cimetidine or antacid.

This study was designed to compare the rates of duodenal ulcer healing and recurrence after treatment with cimetidine or antacid. Patients with endoscopically documented duodenal ulcer received cimetidine, 1200 mg daily, or Mylanta II, 7 oz daily, in a randomized, double-blind trial. For the 69 patients in each group who completed the healing phase of the trial, endoscopic ulcer healing was almost identical. At 2, 4, and 6 wk, the cumulative percent healed on antacid was 33%, 64%, and 80%, and on cimetidine it was 25%, 62%, and 86%. The 114 patients with healed ulcer were observed on no therapy and underwent additional endoscopy to detect recurrences when symptomatic or at 3, 6, and 12 mo. There was no difference in the frequency of recurrences between treatments. At 3 and 6 mo, the cumulative percentages of patients with recurrence were 29% and 56% after antacid therapy and 36% and 55% after cimetidine therapy. Some patient variables were associated with delayed ulcer healing or ulcer recurrence. These included sex, pain frequency, smoking, disease duration, and acid secretion.

Aluminum Hydroxide↗