Biomedical subjects

S Ponce de Leon

Publications and source records attributed to S Ponce de Leon.

11 recordsLinked to original sources

PubMed1999

Impaired metoclopramide-induced pituitary prolactin release in men with human immunodeficiency virus infection.

To investigate whether metoclopramide-induced prolactin release is impaired in HIV-infected men, we studied 10 clinically healthy HIV-negative adult men (group 1) and 10 consecutive HIV-positive adult men (group 2) with anti-HIV antibodies confirmed by Western blot analysis and a CD4 cell count from 13 to 570x10(6)/L. After a 10- to 12-hour overnight fast, three basal blood samples were obtained at 15-minute intervals (-30, -15, and 0 minutes) and thereafter at 15, 30, 60, 90, 120, 180, and 240 minutes after a 10-mg intravenous bolus of metoclopramide. Duplicate serum prolactin concentrations were measured in each sample with commercially available radioimmunoassay kits. No significant differences between groups were observed in basal prolactin levels. Group 2 had lower serum prolactin concentrations than group 1 throughout the test (P< or =.002). The area under the prolactin curve (mean +/- SD) was also lower in group 2 than in group 1 (7156+/-1433 ng/mL/240 min vs. 12430+/-2454 ng/mL/240 min, P<.0001), and the area under the prolactin curve had a significant correlation with the CD4 cell counts (r = 0.7912, P<.001). These findings suggest that the hypothalamic dopaminergic tone, although present, was clearly diminished in these HIV-positive men regardless of their clinical stage.

Adult↗

PubMed1993

Influence of infarct-related artery patency on the indexes of parasympathetic activity and prevalence of late potentials in survivors of acute myocardial infarction.

OBJECTIVES: The purpose of this study was to determine whether infarct-related coronary artery patency influences myocardial electrical stability as measured by the prevalence of late potentials or heart rate variability. BACKGROUND: Several studies have suggested that loss of vagal activity is associated with an increased incidence of arrhythmic death after myocardial infarction. METHODS: A short-duration, high resolution electrocardiogram (ECG) was performed before hospital discharge in 175 patients with a first myocardial infarction. Seventy-three patients received thrombolytic therapy. All patients underwent coronary angiography. Coronary occlusion was defined as minimal or no anterograde flow. Eighty-eight patients (50.3%) had an occluded infarct-related artery. Sixty-two healthy subjects served as control subjects to determine the normal range of heart rate variability. RESULTS: Comparison between the control group and patients without patency of the infarct-related artery in the time domain and spectral analyses revealed in the latter patients a reduced heart rate variability (p < 0.0001) and a lower power spectrum density in both the 0.05- to 0.15-Hz band (p < 0.0001) and the 0.15- to 0.35-Hz band (p < 0.0001). The heart rate variability in patients with late potentials was lower than in those with a normal signal-averaged ECG. Those patients with spontaneous or thrombolysis-induced reperfusion have less occurrence of late potentials and higher parasympathetic activity than do patients with a closed artery. CONCLUSIONS: This study suggests that the patency of the infarct-related artery determines both the absence of late potentials and the preservation of vagal tone and may explain the reduction in mortality induced by thrombolytic therapy in myocardial infarction.

Adult↗

PubMed1991

Post-surgical nasal cellulitis outbreak due to Mycobacterium chelonae.

An outbreak of post-rhinoplasty nasal cellulitis due to Mycobacterium chelonae in a secondary care centre is described. A case-control study demonstrated that the use of inadequately sterilized surgical equipment in the Otorhinolaryngology Department was a risk factor. The causal organism was cultured from the equipment, from the surface of the operating theatre lamp, adhesive tape and from two of the hospital's general water tanks. Introduction of effective instrument sterilization methods, monitored with biological controls, the use of new air filters and cleansing and disinfection of hospital water tanks, were sufficient to control the outbreak. The antimicrobial susceptibilities of the causal organism were consistently different from those previously reported in M. chelonae.

Case-Control Studies↗

PubMed1990

Recovery of HIV antigen in peritoneal dialysis fluid.

We investigated the presence of HIV antigen in dialysis fluid of patients with end-stage renal disease (ESRD) undergoing continuous ambulatory peritoneal dialysis (CAPD), previously known to be infected with this virus. Sixteen adult patients and 6 adult volunteers were included in the study in 4 groups as follows: Group A: 3 patients on CAPD, previously known to be positive for serum HIV antibodies; Group B: 7 patients on CAPD, serum HIV negative; Group C: 6 AIDS patients without renal disease; and Group D: 6 healthy volunteers. Of the 3 patients of Group A, the HIV-1 Ag was positive in dialysis fluid in only 2. In 1, serum Ab and Ag were present, while in the others only serum Ab was detected. The samples from Group B were all negative for the viral antigen in dialysis fluid. We conclude that dialysis fluid of HIV-infected patients may contain the Ag and is therefore potentially infective. The presence of the HIV antigen was not constant, and was not related to antigenemia. It is possible that the presence of the Ag depends on local factors that influence viral replication or to alterations in the permeability of the peritoneal membrane. We discuss other possible factors that could influence the presence of viral Ag in peritoneal dialysis fluid.

Acquired Immunodeficiency Syndrome↗

PubMed1989

Relationship between antiphospholipid antibodies and recurrent fetal loss in patients with systemic lupus erythematosus and apparently healthy women.

We studied 199 patients with systemic lupus erythematosus (SLE) who had been at risk for recurrent fetal loss. Thirty-six had had recurrent fetal loss. These patients, plus a group of 38 healthy women with history of recurrent fetal loss and a group of healthy women who had had at least 3 pregnancies, were tested for antiphospholipid antibodies (APLA) of the 3 major immunoglobulin isotypes using an ELISA method with cardiolipin as antigen. Thirty of the 36 patients with SLE with recurrent fetal loss, 23 of the 163 patients with SLE without recurrent fetal loss, 3 of the 38 healthy women with recurrent fetal loss and no healthy woman with normal obstetric histories had APLA. In all but 3 of the patients with SLE with recurrent fetal loss these included APLA of the IgG isotype. Considering the odds ratio of having recurrent fetal loss as 1 for those patients with SLE without APLA, we found it to be 10.54 times higher in patients with SLE with high titer APLA. Titers of IgG APLA were also 3.2 times higher in patients with SLE with recurrent fetal loss than in those without. We conclude that recurrent fetal loss associates strongly with APLA of the IgG isotype.

Abortion, Habitual↗

PubMed1986

Control of emergence of multi-resistant gram-negative bacilli by exclusive use of amikacin.

Results of a three-year prospective study of amikacin as the only aminoglycoside used at the Instituto Nacional de la Nutrición "Salvador Zubirán" are presented. During the initial three-month baseline period, resistance to amikacin, gentamicin, and tobramycin among 870 gram-negative bacterial isolates was 3.2 percent, 17.4 percent, and 11.2 percent, respectively. In this period, the overall consumption of aminoglycosides was 69 percent for gentamicin, 30.5 percent for amikacin, and 0.5 percent for tobramycin. In the following period of exclusive amikacin use, sensitivity patterns of 9,344 gram-negative strains isolated over three years were recorded. During this period, amikacin constituted 99.3 percent of all aminoglycosides used. The percentage of gentamicin-resistant gram-negative strains declined to 7.4 percent (p less than 0.0001), whereas the percentage of amikacin-resistant strains did not change significantly. Quarterly trend analysis of aminoglycoside-resistant strains also demonstrated a significant decrease in gentamicin resistance (p less than 0.005) and an overall steady state of amikacin resistance. It is concluded that the exclusive use of amikacin was not accompanied by a significant increase in amikacin resistance during a three-year period, and may even lead to a decrease in resistance to gentamicin and tobramycin among most gram-negative organisms.

Amikacin↗

PubMed1986

Microbiologic studies of coagulase-negative staphylococci isolated from patients with nosocomial bacteraemias.

We studied 50 strains of coagulase-negative staphylococci (CNS) isolated from 50 patients with hospital-acquired bacteraemia, identified by prospective surveillance at the University of Virginia Hospital between March 1981 and September 1982. Using the Staph-Ident System for speciation, we found that 37 strains (74%) were Staphylococcus epidermidis, 7 (14%) Staph. hominis, 3 (6%) Staph. haemolyticus and 3 (6%) Staph. warneri. 33 (66%) of the strains produced slime and a higher proportion of the Staph. epidermidis group (75%) than the non-epidermidis group (46%), did so. Minimal inhibitory concentrations (MIC) were determined by a microdilution technique with 20 different antibiotics. There was no difference in geometric mean MICs between slime producers and non-slime producers within either the epidermidis or non-epidermidis group. The most potent antibiotics against Staph. epidermidis (MIC90 mg l-1) were rifampin (0.05), netilmicin (0.05), amikacin (2.9), thienamycin (0.75), teichomycin (0.85), vancomycin (1.0) and nafcillin (0.39). On the other hand strains were resistant to tobramycin (15), moxalactam (50), fosfomycin (greater than 64), and clindamycin (greater than 64). Overall, eight (16%) of the CNS strains were resistant to methicillin, three of which were Staph. haemolyticus. The non-epidermidis strains were more resistant than the Staph. epidermidis strains to most beta-lactam antibiotics. Differences in antibiograms indicate that speciation of CNS may prove useful for clinical and epidemiologic purposes.

Anti-Bacterial Agents↗

PubMed1984

Hospital-acquired bloodstream infections with Staphylococcus epidermidis. Review of 100 cases.

During a seven-year study period, 1976 to 1982, this prospective surveillance program detected 108 episodes of nosocomial bacteremia caused by coagulase-negative staphylococci (seven per 10,000 admissions). Chart reviews were subsequently performed in 100 patients primarily to define the patient population and determine outcome of infection. Seventy-two patients had at least two culture bottles that showed growth of coagulase-negative staphylococci plus one or more cultures that showed growth at another site or on a vascular catheter. Most of the patients were in the early or later stages of life: 20 were premature infants, 20 additional infants were under one year of age, and 35 patients were 50 years of age or older. Seventy-three patients were in intensive care areas at the time of the infection. The mortality for the 100 patients studied was 34 percent, with a rate of 9 percent per week after infection. Ninety-three patients had arterial or central lines in place prior to bacteremia and, in 36 reviewed, the mean duration of use of each type of catheter (5.1 days or more) was longer than recommended. In 56 percent of 46 catheters cultured semiquantitatively, there was growth of coagulase-negative staphylococci. The presence of coagulase-negative staphylococci in the blood is associated with significant mortality in hospitalized patients. No longer can their presence in the blood be disregarded as mere contaminants, especially in patients in critical care units.

Adolescent↗

PubMed1984

Polymicrobial bloodstream infections related to prolonged vascular catheterization.

Between June 15 and August 7, 1982, six patients in a medical ICU developed primary nosocomial bloodstream infections. Nine different organisms were isolated during this epidemic. In three patients, contamination of intravascular lines was documented; and in the other three, the relationship was strongly suggested. The infected patients were compared to three groups of randomly selected controls: group A from the epidemic period; group B from the pre-epidemic period; and group C from both periods and matched for underlying disease. The infected patients had indwelling arterial and pulmonary artery catheters in place almost twice as long (6.3 +/- 2.8 days and 6.8 +/- 3.9 days, respectively) as most controls. Our evidence suggests that the guideline for changing catheters may have been ignored when the resident house staff changed. This is the first outbreak related to vascular catheters in which several different organisms were involved; it represents a new type of epidemic related to a common technique problem rather than a common source reservoir.

Adolescent↗

PubMedDate not supplied

Hospital-acquired infections in intensive care unit patients: an overview with emphasis on epidemics.

Surveillance activities for the detection of nosocomial infections at the University of Virginia Hospital (Charlottesville, Virginia) and at hospitals participating in the Virginia Statewide Infection Control Program have focused on outbreaks and device-related infections which are potentially preventable. Eleven outbreaks of nosocomial infections were identified at the University of Virginia Hospital between January 1, 1978 and December 31, 1982 (9.8 outbreaks/100,000 admissions). Ten of the 11 were centered in critical care units. The 269 patients involved in the epidemics represented 0.2% of all hospital admissions and 3.7% of all patients who developed nosocomial infections. Eight of the 11 outbreaks involved infection of the bloodstream, and the 90 patients who developed a bloodstream infection as part of an epidemic represented 8% of all patients with nosocomial bloodstream infections identified during the five-year study period. The reservoir of the 11 outbreaks involved devices (5), contaminated cocaine (1), probable blood products (1), other patients (3), and nursing personnel (1). Forty-one percent of all nosocomial bloodstream infections and 41% of all nosocomial pneumonias occurred in intensive care units (ICUs). In 38 hospitals in the state of Virginia with ICUs and practitioners who voluntarily reported surveillance data between June 1, 1980 and May 31, 1982, there were 264,757 patients admitted and a crude infection rate of 3%. Of note is that 1,867 of the 7,407 nosocomial infections (25%) occurred in the ICU patients. Several factors point to a compelling argument that the highest priority in infection control resources be assigned to the prevention and control of ICU infections: ICU patients often have serious device-related infections and may be identified as high risk prior to infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Cross Infection↗

PubMedDate not supplied

[A 20-year-old epidemics].

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Acquired Immunodeficiency Syndrome↗