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Biomedical subjects

L A Hill

Publications and source records attributed to L A Hill.

18 recordsLinked to original sources
PubMed1997

Nosocomial respiratory syncytial virus infections: prevention and control in bone marrow transplant patients.

OBJECTIVE: To assess the effectiveness of a multifaceted infection control strategy in limiting the nosocomial transmission of respiratory syncytial virus (RSV) infection to patients in a bone marrow transplant (BMT) unit. DESIGN: Before/after trial. SETTING: University-affiliated tertiary cancer center. PATIENTS: Adult BMT recipients hospitalized during two consecutive wintertime community outbreaks of RSV infection. INTERVENTIONS: An infection control strategy against nosocomial RSV infection was implemented in the BMT unit in February 1993. The strategy involved prompt identification, isolation, and cohorting of RSV-infected patients; prompt therapy with aerosolized ribavirin; use of masks and gloves by anyone entering an infected BMT patient's room; screening visitors for respiratory symptoms; restricting visitation by all children under 12 years of age and all family members and other visitors with RSV symptoms; and restricting symptomatic hospital staff from working in the BMT unit. RESULTS: After implementation of the multifaceted infection-control strategy, there were four cases of nosocomial RSV infection in 3,870 patient days (incidence density, 1.0 case/1,000 patient days) compared with 14 cases of nosocomial RSV infection in 3,152 patient days (incidence density, 4.4 cases/1,000 patient days) during the 1992-1993 RSV season (rate ratio, 4.4; 95% confidence interval [CI95]. 1.4-17.9: P < .01). This decrease in incidence occurred despite a comparable prevalence of community-acquired RSV cases between the two seasons (2.2% vs 3.2% in 1992-1993 and 1993-1994, respectively; prevalence ratio, 0.7; CI95, 0.2-2.1; P = 0.5). CONCLUSION: Institution of a multifaceted infection control strategy significantly reduced the frequency of nosocomial RSV infection in a high-risk group of adult BMT recipients.

Adult↗
PubMed1995

p53 mutations in nonmelanoma skin cancer of the head and neck: molecular evidence for field cancerization.

Multiple and distinct p53 mutations were detected by DNA sequence analysis in tumor and adjacent nonmalignant skin samples from eight patients with nonmelanoma skin cancer of the head and neck, providing unambiguous evidence for field cancerization. The mutations consisted of C-->T transitions at dipyrimidine sequences (30% of all single base substitutions), T-->C transitions (47%), and G-->T transversions (12%), suggesting that other carcinogens may act along with UV radiation in the development of nonmelanoma skin cancer. Patient interviews revealed that, in addition to substantial exposure to solar UV radiation, most had a history of smoking and were exposed to carcinogens from industrial or agricultural sources. These data show that extensive molecular epidemiological investigations are necessary to elucidate risk factors associated with the disease in localities where patients often report substantial exposure to environmental carcinogens.

Adult↗
PubMed1994

Prevention of central venous catheter-related infections by using maximal sterile barrier precautions during insertion.

OBJECTIVE: In many hospitals, the only sterile precautions used during the insertion of a nontunneled central venous catheter are sterile gloves and small sterile drapes. We investigated whether the use of maximal sterile barrier (consisting of mask, cap, sterile gloves, gown, and large drape) would lower the risk of acquiring catheter-related infections. DESIGN: Prospective randomized trial. SETTING: A 500-bed cancer referral center. METHODS: We randomized patients to have their nontunneled central catheter inserted under maximal sterile barrier precautions or control precautions (sterile gloves and small drape only). All patients were followed for 3 months postinsertion or until the catheter was removed, whichever came first. Catheter-related infections were diagnosed by quantitative catheter cultures and/or simultaneous quantitative blood cultures. RESULTS: The 176 patients whose catheters were inserted by using maximal sterile barrier precautions were comparable to the 167 control patients in underlying disease, degree of immuno-suppression, therapeutic interventions, and catheter risk factors for infections (duration and site of catheterization, number of catheter lumen, catheter insertion difficulty, reason for catheter removal). There were a total of four catheter infections in the test group and 12 in the control group (P = 0.03, chi-square test). The catheter-related septicemia rate was 6.3 times higher in the control group (P = 0.06, Fisher's exact test). Most (67%) of the catheter infections in the control group occurred during the first 2 months after insertion, whereas 25% of the catheter infections in the maximal sterile precautions group occurred during the same period (P < 0.01, Fisher's exact test). Cost-benefit analysis showed the use of such precautions to be highly cost-effective. CONCLUSION: Maximal sterile barrier precautions during the insertion of nontunneled catheters reduce the risk of catheter infection. This practice is cost-effective and is consistent with the practice of universal precautions during an invasive procedure.

Adolescent↗
PubMed1990

A new predictive equation for resting energy expenditure in healthy individuals.

A predictive equation for resting energy expenditure (REE) was derived from data from 498 healthy subjects, including females (n = 247) and males (n = 251), aged 19-78 y (45 +/- 14 y, mean +/- SD). Normal-weight (n = 264) and obese (n = 234) individuals were studied and REE was measured by indirect calorimetry. Multiple-regression analyses were employed to drive relationships between REE and weight, height, and age for both men and women (R2 = 0.71): REE = 9.99 x weight + 6.25 x height - 4.92 x age + 166 x sex (males, 1; females, 0) - 161. Simplification of this formula and separation by sex did not affect its predictive value: REE (males) = 10 x weight (kg) + 6.25 x height (cm) - 5 x age (y) + 5; REE (females) = 10 x weight (kg) + 6.25 x height (cm) - 5 x age (y) - 161. The inclusion of relative body weight and body-weight distribution did not significantly improve the predictive value of these equations. The Harris-Benedict Equations derived in 1919 overestimated measured REE by 5% (p less than 0.01). Fat-free mass (FFM) was the best single predictor of REE (R2 = 0.64): REE = 19.7 x FFM + 413. Weight also was closely correlated with REE (R2 = 0.56): REE = 15.1 x weight + 371.

Adult↗
PubMed1987

The effect of Pseudomonas aeruginosa cytotoxin and toxin A on human polymorphonuclear leukocytes.

After exposure to cytotoxin or toxin A of Pseudomonas aeruginosa, the ultrastructure of resting and phagocytosing human polymorphonuclear leukocytes (PMNL) and of cells of P. aeruginosa strain 1348A was studied by transmission (TEM) and scanning (SEM) electronmicroscopy, and by light microscopy (LM) after histochemical staining of cytoplasmic granules. Cytotoxin caused marked clumping and destruction of PMNL, pyknotic nuclear changes with bleb formation, and release of cytoplasmic granules; phagocytosis was markedly diminished. In contrast, after exposure to toxin A, PMNL phagocytosed actively, but their cytoplasmic pseudopodia were markedly irregular and their nuclei pyknotic. Colloidal-gold-labelled cytotoxin showed an affinity for the cytoplasmic membranes, nuclei and granules of PMNL. Cytotoxin had no apparent effect on cells of P. aeruginosa strain 1348A but there was polar separation of the cytoplasmic membrane in bacteria exposed to toxin A. Cytotoxin and toxin A appear to be important in the pathogenesis of infections caused by P. aeruginosa.

ADP Ribose Transferases↗
PubMed1987

Effect of Kupffer cell phagocytosis of erythrocytes and erythrocyte ghosts on susceptibility to endotoxemia and bacteremia.

The phagocytosis of erythrocytes by macrophages has previously been shown to depress macrophage function. In this study we compared the effect of the phagocytosis of erythrocytes and erythrocyte ghosts by Kupffer cells on the duration of the depression of complement receptor clearance function and host defense against endotoxemia and bacteremia. Phagocytosis of erythrocytes and erythrocyte ghosts was induced in rats by the injection of rat erythrocytes or erythrocyte ghosts coated with anti-rat erythrocyte immunoglobulin G (EIgG and GIgG, respectively). The hepatic uptake of EIgG and GIgG (17.4 X 10(8)/100 g) occurred during the first 30 min after injection. The digestion of phagocytized EIgG and GIgG, as assessed by electron microscopy, was complete at 24 and 3 h after injection, respectively. The depression of Kupffer cell complement receptor clearance function caused by EIgG and GIgG returned to normal by 6 h after injection of EIgG and by 3 h after injection of GIgG. Phagocytosis of EIgG depressed the survival rate after endotoxemia and bacteremia when endotoxin or bacteria were injected at 30 min after EIgG. The survival rate returned to normal when the endotoxin and bacteria were injected at 12 and 6 h after the EIgG, respectively. Phagocytosis of GIgG did not depress the survival rate after endotoxemia and bacteremia. Thus, compared with erythrocytes, erythrocyte ghosts are more rapidly digested after phagocytosis, depress complement receptor function for a shorter period of time, and cause less depression of host defense. These findings indicate that the contents of erythrocytes play an important role in the impairment of host defense caused by the phagocytosis of erythrocytes by Kupffer cells.

Animals↗
PubMed1987

Endothelial injury and pulmonary congestion characterize neurogenic pulmonary edema in rabbits.

The objectives of the present study were to determine whether an intracisternal injection of fibrinogen-sodium citrate, a model of neurogenic pulmonary edema (NPE), produces protein-rich or protein-poor pulmonary edema, and to determine whether the edema is associated with pulmonary vascular hypertension and pulmonary congestion. Fibrinogen (6-10 mg/ml) dissolved in 0.055 M sodium citrate was injected into the cisterna magna of six New Zealand White rabbits. Six additional rabbits were injected with saline to control for the effects of intracranial hypertension and pulmonary vascular hypertension. The fibrinogen-sodium citrate solution or sodium citrate alone, as opposed to saline, produced systemic and pulmonary vascular hypertension, pulmonary edema, hypoxemia, hypercapnia, and acidosis. The lungs from fibrinogen-injected rabbits were edematous, congested, and liverlike in appearance. Tracheal froth that was blood tinged and protein rich was present in five of the six rabbits. Microscopic examination of lung biopsies revealed erythrocytes and plasma in the alveoli and focal injury to the pulmonary microvascular endothelium. Fibrinogen-sodium citrate increased (P less than 0.05) the extravascular lung water (EVLW) (10.3 +/- 2.0 vs. 5.5 +/- 0.6 g, means +/- SE), lung blood weight (9.7 +/- 1.3 vs. 3.8 +/- 0.6 g), total dry lung weight (3.2 +/- 0.4 vs. 2.0 +/- 0.1 g), and the EVLW-to-blood-free dry lung weight ratio (7.0 +/- 0.8 vs. 4.0 +/- 0.3 g) from saline-control values. There was no difference in the blood-fre dry lung weight (1.4 +/- 0.1 vs. 1.3 +/- 0.1 g) between the two groups. These findings demonstrate that pulmonary congestion, pulmonary vascular hypertension, and focal endothelial injury contribute to the development of NPE.

Animals↗
PubMed1980

Detection of spermatozoal antibodies by radioassay: a comparative evaluation.

Antibodies to human spermatozoa were produced in rabbits and a portion of each rabbit antiserum was purified by ammonium sulfate fractionation. Fractionated and unfractionated antisera were used to compare a new indirect radioimmunoassay for spermatozoal antibodies with one indirect immunofluorescent, one microagglutination, and one macroagglutination assay. No significant difference in sensitivity was found when comparing the two agglutination assays. The indirect immunofluorescent antibody test appeared to be more sensitive than the agglutination tests, but endpoints were more difficult to interpret. The radioimmunoassay was the most sensitive procedure tested. The radioassay is not difficult to perform, but requires the preparation of a 125I-labeled antiglobulin reagent.

Animals↗