PubMed Health⌕ Search

Biomedical subjects

P Rivera

Publications and source records attributed to P Rivera.

At least 19 recordsLinked to original sources
PubMed1990

The first cases of Helicobacter pylori (Campylobacter pylori) reported from Costa Rica.

Two gastric antrum biopsies of each of 92 consecutive patients undergoing gastroendoscopy were studied. The first biopsy was cultured for Helicobacter (Campylobacter) pylori. The second specimen was fixed and processed for histopathological analysis. The bacteria were isolated from 34 (81%) of 42 patients with nonspecific chronic gastritis, 19 (90%) of 21 cases of duodenal or gastric peptic ulcer, and from 3 (23%) of 13 normal patients. The overall frequency of isolation was 62 (67%) of the 92 cases.

Adult↗
PubMed1989

Prevalence of depression in family caregivers.

Family caregivers who sought help to increase their coping skills (N = 158) and caregivers who volunteered for a longitudinal study of Alzheimer's disease (N = 58) were screened for depression. Among help-seekers, 46% had depression according to Research Diagnostic Criteria (RDC), but among non-help-seekers, only 18% met this criterion. In general, women were more depressed than men, but no major differences in the extent of depression were found in those who cared for more impaired persons.

Adaptation, Psychological↗
PubMed1989

Mannose-resistant hemagglutination, enzyme-linked immunosorbent assay, and immune electron microscopy for detection of K99 fimbrial antigen in Escherichia coli from calves.

Mannose-resistant hemagglutination (MRHA) was evaluated for identification of Escherichia coli with K99 fimbriae. The sensitivity and specificity of MRHA, relative to the enzyme-linked immunosorbent assay, were 21 and 79%, respectively. Disagreement between the tests may have been due in part to separation of pili from the cells, with resultant enzyme-linked immunosorbent assay-positive, MRHA-negative tests. MRHA was not useful as the sole means for the identification of E. coli with K99 fimbriae.

Animals↗
PubMed1986

[Morphological changes induced by ampicillin in Campylobacter].

Morphologic changes in Campylobacter fetus ssp. jejuni were evaluated as cultivated on thioglycollute broth, containing minimum of 0.1, 1.3 and 10 Ampicillin minimal inhibitory concentration (MIC). During the first four hours of incubation, no changes occurred in the presence of 0.1 MIC; but with the rest of the ampicillin doses, even at the first hour, a proportion larger than 5% of filament-policurved forms was found, and it increased with the incubation time. The greatest number of altered bacteria was found with the use of 10 MIC. No other morphologic changes were observed.

Ampicillin↗
PubMed1985

Effects of starvation and exercise on concentrations of citrate, hexose phosphates and glycogen in skeletal muscle and heart. Evidence for selective operation of the glucose-fatty acid cycle.

Concentrations of citrate, hexose phosphates and glycogen were measured in skeletal muscle and heart under conditions in which plasma non-esterified fatty acids and ketone bodies were physiologically increased. The aim was to determine under what conditions the glucose-fatty acid cycle might operative in skeletal muscle in vivo. In keeping with the findings of others, starvation increased the concentrations of glycogen, citrate and the fructose 6-phosphate/fructose 1,6-bisphosphate ratio in heart, indicating that the cycle was operative. In contrast, it decreased glycogen and had no effect on the concentration of citrate or the fructose 6-phosphate/fructose 1,6-bisphosphate ratio in the soleus, a slow-twitch red muscle in which the glucose-fatty acid cycle has been demonstrated in vitro. In fed rats, exercise of moderate intensity caused glycogen depletion in the soleus and red portion of gastrocnemius muscle, but not in heart. In starved rats the same exercise had no effect on the already diminished glycogen contents in skeletal muscle, but it decreased cardiac glycogen by 25-30%. After exercise, citrate and the fructose 6-phosphate/fructose 1,6-bisphosphate ratio were increased in the soleus of the starved rat. Significant changes were not observed in fed rats. The data suggest that in the resting state the glucose-fatty acid cycle operates in the heart, but not in the soleus muscle, of a starved rat. In contrast, the metabolite profile in the soleus was consistent with activation of the glucose-fatty acid cycle in the starved rat during the recovery period after exercise. Whether the cycle operates during exercise itself is unclear.

Animals↗
PubMed1985

[Campylobacter fetus ssp. jejuni, Aeromonas hydrophila, helicoidal bacteria and coronavirus in the murine intestine].

Intestinal contents of 28 laboratory-bred white mice and 6 wild-caught rats were extracted and observed with phase-contrast and transmission electron microscopy; cultures were made in Butzler agar and aeromonas, incubated in microaerobiosis, at 37 degrees C for 5 days. In three mice and two rats, helicoidal bacteria were observed, with 8 to 11 periplasmic fibers and terminal branches of 8 to 11 structures, similar to flagella. In one of the rats, coronavirus-like particles were observed. Campylobacter fetus ssp. jejuni was isolated in cultures from two mice and Aeromonas hydrophila from two rats.

Aeromonas↗
PubMed1984

[Study of bacterial motility and rate of movement using a closed circuit television].

Speed and motion patterns of Campylobacter fetus ssp. jejuni, Escherichia coli and Pseudomonas aeruginosa were recorded using a closed circuit television camera attached to a phase contrast microscope. A Sony video analysis system was used to stop frame videotape at 1/7th and 1/15th. Bacterial speeds were: Campylobacter 29.2 micron/s, E. coli 8.9 micron/s and P. aeruginosa 16.8 micron/s.

Campylobacter fetus↗
PubMedDate not supplied

Diagnostic and prognostic significance of beta 2-microglobulin during HIV infection.

The serum levels of beta 2-microglobulin (beta 2-m) were determined in 80 intravenous drug addicts (IVDA) with acquired immunodeficiency syndrome (AIDS), in 128 HIV-positive IVDA with persistent generalized lymphadenopathy (PGL) and in 44 HIV-seronegative IVDA. Seventy-two out of 80 (90%) AIDS patients had elevated serum beta 2-m levels and high levels of beta 2-m were also found in 105 of 128 (82%) HIV-infected subjects without AIDS. The mean beta 2-m level was significantly higher in HIV-infected patients with PGL than in HIV-negative IVDA. Nine out of 64 (14%) PGL patients developed AIDS in a period of 24-54 months. In these patients the mean beta 2-m level (5.16 +/- 2.37 mg/l), obtained from sera stored at the first observation, was significantly higher than in the other PGL patients (3.40 +/- 1.03 mg/l); in particular, 5 out of 7 PGL patients with beta 2-m levels greater than 5.0 mg/l showed an advanced disease.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Diagnosis of Helicobacter pylori: comparison of an urease test, histological visualization of curved bacteria and culture.

Helicobacter pylori was investigated in 189 patients for culture, microscopic visualization of campylobacter-like organisms (CLO) and a ten minute urease test. In 136 (72%) the bacteria was isolated, and in 98 of them CLO were histologically detected. Specificity, sensitivity, positive and negative predictive values of microscopic visualization of CLO were: 0.77, 0.73, 0.97 and 0.51, respectively; 98 culture-positive patients were urease test positive. Specificity, sensitivity, positive and negative predictive values of the urease test were: 0.83, 0.72, 0.92 and 0.54, respectively. Comparing the urease test with culture of H. pylori combined with microscopic visualization of CLO, its specificity, sensitivity, positive and negative predictive values were: 0.95, 0.71, 0.98 and 0.48, respectively. Probably, these values are not real, since bacteria different from H. pylori could be misclassified as CLO.

Clinical Enzyme Tests↗
PubMedDate not supplied

A low cost method to produce a gaseous environment for the isolation of Helicobacter pylori.

A low cost method (LCM) to produce a gaseous environment for the isolation of Helicobacter pylori, was compared with the standard Gas Park system. The LCM uses a carbonated antacid tablet, a plastic bag with tap water, a candle, and a wide-mouthed glass jar provided with a tight-fitting metallic screw cap and a rubber gasket. Antral gastric biopsies from 153 cases were incubated by duplicate on blood agar plates and treated with the two methods. In 95 cases the agent was isolated from both, and only from the standard method in 10 cases; the opposite condition was found in five cases, and 43 were negative. That difference is not significant (Pearson's chi 2 = 93.25 p > 0.05).

Aspirin↗