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Biomedical subjects

J M Hughes

Publications and source records attributed to J M Hughes.

At least 19 recordsLinked to original sources
PubMed1992

Menstrual function after tubal sterilization.

More than 10 million women in the United States have undergone tubal sterilization. There has been concern that this procedure may increase the risk of later menstrual dysfunction. The Collaborative Review of Sterilization (CREST) is a large, multicenter, prospective study of tubal sterilization in the United States. This report describes CREST participants who were interviewed immediately before sterilization and again in annual poststerilization interviews for up to 5 years between 1978 and 1988. The authors analyzed reported changes in six menstrual cycle characteristics for 5,070 women undergoing interval sterilizations. Longitudinal, multivariate regression was used to adjust for baseline menstrual function and other potential confounders. Five years after sterilization, 35% of the CREST participants reported high levels of menstrual pain, 49% reported heavy or very heavy menstrual flow, and 10% reported spotting between periods. In contrast to the fifth year, the first year of follow-up was similar to presterilization menstrual function; in the first year, 27% of participants reported high menstrual pain, 41% reported heavy menstrual flow, and 7% reported spotting. These findings may be affected by aging of the cohort and other study limitations, but they suggest that if tubal sterilization leads to changes in menstrual function, such changes may take some time to develop.

Adolescent↗
PubMed1992

Effects of increased inspired oxygen concentrations on exercise performance in chronic heart failure.

Exercise capacity in patients with stable heart failure may be influenced by prolonged drug treatment or exercise training, but acute interventions are generally thought to have little effect. Cardiorespiratory responses to exercise were studied in 12 consecutive patients with chronic congestive heart failure who underwent serial submaximal and maximal exercise tests at inspired oxygen concentrations of 21% (room air), 30%, and 50%. Mean (SD) exercise duration during progressive testing to maximum exercise capacity was prolonged from 548 (276) s on room air to 632 (285) s on 50% oxygen (p = 0.012). During steady-state exercise at 45 W, oxygen enrichment to 50% was associated with significantly increased arterial oxygen saturation (94.6 [1.9]% to 97.5 [1.3]%), and significantly reduced minute ventilation (36.1 [8.6] l/min to 28.1 [5.9] l/min), cardiac output (7.5 [2.3] l/min to 6.5 [1.9] l/min), and subjective scores for fatigue and breathlessness (13.9 [3.1] to 11.5 [3.5]) compared with room air intermediate changes were observed with 30% inspired oxygen. Increased inspired oxygen concentrations can improve exercise performance acutely and modify the ventilatory response to exercise in patients with heart failure. Hyperoxia reduces ventilatory response and circulatory demand while maintaining oxygen delivery at a given workload. The potential benefits of increased inspired oxygen concentrations in the treatment of chronic heart failure merit further assessment.

Adult↗
PubMed1992

The metabolism of noradrenaline in the sheep and the effect of dry matter intake upon the production of a metabolite, urinary vanillylmandelic acid.

1. The metabolism of noradrenaline was investigated in the sheep using 3H-noradrenaline injected subcutaneously or intravenously. 2. Analysis of urine collected over 24 hr showed that the bulk of 3H-noradrenaline was rapidly degraded and excreted via the urine. The principle metabolite was the conjugated amine as well as monohydroxy phenyl glycol and vanillylmandelic acid (VMA) previously reported for the rat. 3. Urinary VMA from lambs of two breeds noted for differences in fat (Southdown and Suffolk) increased curvilinearly with dry matter intake and there was a significant breed difference in regression with intake. 4. It is feasible that differences in noradrenaline production could contribute to differences in body composition between breeds.

Animals↗
PubMed1992

Total quality management in a 300-bed community hospital: the quality improvement process translated to health care.

Winter Park Memorial Hospital (Winter Park, Florida) began implementation of a well-strategized plan for total quality management (TQM) in 1987. Having no guidelines for applying TQM to health care but using the industrial quality management techniques of Philip Crosby Associates, Inc, the hospital made the transition and saved thousands of dollars in the process. This article describes the transition, especially the integral part played by the Medical Staff Quality Council in changing the hospital's culture.

Florida↗
PubMed1992

A chronic pulmonary syndrome associated with graft-versus-host disease after allogeneic marrow transplantation.

Of 143 consecutive patients who survived at least 6 months after bone marrow transplantation (allogeneic [n = 131]; syngeneic [n = 5]; or autologous [n = 7]) and whose pulmonary function was evaluated before and on at least 2 occasions after BMT, 29 (20%) developed a chronic pulmonary syndrome without evidence for an infectious etiology. Twenty-eight (97%) presented with cough and 22 (76%) with dyspnea; abnormal chest signs were crackles in 23 (79%) and wheeze in 22 (76%). Chest roentgenogram showed pulmonary infiltrates in 15 (52%) cases but was normal in 14 (48%). All patients had major reductions in lung volumes (forced expiratory volume in 1 sec [FEV1]; relaxed vital capacity [VC]; and alveolar volume [VA]), and/or diffusing capacity (pulmonary diffusing capacity [TLCO] and single-breath carbon monoxide coefficient [KCO]). The obstructive component varied with only 18 (62%) patients developing overt airways obstruction (FEV1/VC < 75%), and in 6 of this group the fall in lung volumes preceded the onset of airways obstruction. Open lung biopsy (n = 4) showed both bronchiolitis obliterans and chronic patchy interstitial pneumonitis. The development of this syndrome was associated with acute (P < 0.001) and chronic (P < 0.0001) graft-versus-host disease of other organ systems. Twenty-four (83%) patients had a partial or complete response to immunosuppressive agents. Six (21%) have died, five (17%) of pulmonary complications. We suggest that this syndrome may be a manifestation of chronic GVHD involvement of the lung.

Adolescent↗
PubMed1992

Quantification of right to left shunt at rest and during exercise in patients with pulmonary arteriovenous malformations.

BACKGROUND: Current treatment of patients with pulmonary arteriovenous malformations requires serial embolisations by means of steel coils or balloons. Measurement of right to left shunt is the most specific index of response to treatment. A new method of measuring shunt has been developed that is less invasive than traditional methods. METHODS: Right to left pulmonary shunt (expressed as percentage of cardiac output) was measured at rest in 19 patients with pulmonary arteriovenous malformations and six normal subjects by using intravenously injected albumin microspheres labelled with technetium-99m. The technique was compared with a simultaneous shunt measurement in subjects breathing 100% oxygen while they rested. The microsphere technique was adapted to measure the right to left shunt during exercise in 12 patients and five normal subjects with a new method of quantification. RESULTS: The mean (SD) shunt at rest as measured by the microsphere method was 23.2% (15.6%) in the patients and 2.7% (1.2%) in the normal subjects. When these values were compared with those of the 100% oxygen method the difference in mean values was 1% and the limits of agreement between the two methods -32% to +45%. The microsphere method is less invasive (arterial blood gas sampling is not required), quicker, and more comfortable for patients than the 100% oxygen method. In five of the normal subjects the mean (SD) 99mTc microsphere shunt increased from 2.9% (1.3%) at rest to 5.1% (2.9%) during exercise. In the 12 patients studied during exercise the shunt increased from 33.7% (12.7%) at rest to 41.7% (13.3%) during exercise in eight but decreased from 22.6% (2.4%) at rest to 17.6% (2.2%) during exercise in four. Arterial desaturation during exercise correlated with change in the size of the right to left shunt during exercise (r = +0.80). CONCLUSIONS: The microsphere method allows measurement of right to left shunt at rest and during exercise. Serial measurements at rest provide a simple, safe assessment of the physiological response to embolisation in patients with pulmonary arteriovenous malformations.

Adolescent↗
PubMed1992

Regional structure-function correlations in chronic obstructive lung disease measured with positron emission tomography.

BACKGROUND: Positron emission tomography, performed with isotopes of very short half life, can be used to relate local lung tissue density to local ventilation and to the ventilation:perfusion ratio. This method has been used in 10 patients with severe chronic airflow obstruction and differing values for carbon monoxide transfer factor (TLCO) and transfer coefficient (KCO). METHODS: Ventilation (VA) and the ventilation:perfusion ratio (V/Q), lung density, and blood volume were measured regionally in a single transaxial section at mid-heart level with the patients in a supine position. Alveolar volume, extravascular tissue lung density, and perfusion (Q) were derived. Twenty five regions with abnormalities in the ventilation images were analysed. RESULTS: Tissue density showed a negative correlation with the ratio V/Q (r = 0.55) and a positive correlation with Q (r = 0.59) and blood volume (r = 0.65). In four patients with a low carbon monoxide transfer factor (TLCO) and transfer coefficient (KCO) < 50% predicted many regions with low VA had low tissue density and normal or high V/Q. On the other hand, in four patients with TLCO and KCO > 50% predicted many regions with low VA had normal or high tissue density and low values of V/Q. The other two patients had patterns between these two extremes. Individual ratios between mean values of tissue density and V/Q had a positive correlation with KCO (% pred; r = 0.79). CONCLUSIONS: These findings link structural differences with distinctive functional patterns; they reinforce the view that bronchial inflammation or oedema predominate in some patients with chronic airflow obstruction, whereas alveolar destruction is the major feature in others.

Aged↗
PubMed1992

Abnormal lung function in polyurethane foam producers. Weak relationship to toluene diisocyanate exposures.

Exposures to toluene diisocyanate (TDI) were studied for effects on respiratory health of workers in two plants manufacturing polyurethane foams. Intensive personal monitoring was used to characterize job exposures. Of 4,845 12-min personal samples, 9% exceeded 5 ppb and 1% exceeded 20 ppb. Initial questionnaire and spirometry were obtained in 386 workers (88.7% of target population). Current smoking was associated with lower mean FEV1 and FEF25-75, but percent predicted (% pred) means were normal in all smoking categories. Multiple regression showed significant adverse effects of cumulative TDI exposure on initial level of FVC and FEV1 of current smokers, and an effect at borderline significance (p less than 0.063) on FEF25-75 over all smoking categories. Logistic regression showed that chronic bronchitis was more prevalent among those with higher cumulative exposures, after controlling for smoking, age, and sex. Methacholine (MCh) reactivity was associated with reduced airway function, -8.5% pred for FEV1 and -20.0% pred for FEF25-75. In 227 with adequate follow-up, the slopes of annual change were abnormal, for example, FEV1 of -67 ml/yr in current and -53 ml/yr in never smokers. Men had worse FEV1 declines than did women, -71 ml/yr versus -43 ml/yr. TDI exposure, lifetime or concurrent, had no significant effect on slopes, despite its demonstrated effects on initial level of lung function and on prevalence of chronic bronchitis.

Adult↗
PubMed1992

Effects of natriuretic peptides and neutral endopeptidase 24.11 inhibition in isolated perfused rat lung.

We have studied the acute effect of brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) on pulmonary vascular tone in normoxia and acute hypoxia in the absence and presence of a specific inhibitor of neutral endopeptidase 24.11 (NEI, UK 73, 967, candoxatrilat; Pfizer) in the isolated and blood-perfused rat lung preparation. Baseline pulmonary artery pressure (Ppa) was 16.4 +/- 0.3 mm Hg in lungs from normoxic control rats and 22.5 +/- 0.3 mm Hg in lungs from rats kept in hypoxia (FIO2 = 10%) for 7 days. Acute hypoxic pulmonary vasoconstriction (HPV delta Ppa) was similar in normoxic control rats (9.5 +/- 0.6 mm Hg) and chronically hypoxic rats (9.8 +/- 0.9 mm Hg). NEI at 0.07 and 0.2 mg had no effect on baseline Ppa or HPV delta Ppa. Synthetic BNP at 10 nM had no effect on baseline Ppa but produced a 2.8 +/- 0.2 mm Hg reduction in HPV delta Ppa alone and 2.7 +/- 0.2 mm Hg reduction in the presence of 0.07 mg NEI in normoxic control rats. In contrast, ANP at 10 nM produced a significantly greater decrease in HPV delta Ppa in the presence of 0.07 mg NEI (4.8 +/- 0.3 mm Hg, p < 0.05) compared with ANP alone (2.9 +/- 0.4 mm Hg), and similar results were also observed in chronically hypoxic rats. Thus, BNP has a vasodilator effect similar to that of ANP in the pulmonary circulation. Inhibition of neutral endopeptidase 24.11 augments the effects of ANP on HPV but does not influence the pulmonary vascular responses to BNP.

Animals↗
PubMed1992

Timing and magnitude of response of plasma aldosterone concentration to bolus adrenocorticotropin: importance of sodium balance in outpatient testing.

Plasma aldosterone concentration (PAC) response to ACTH is utilized in clinical and experimental protocols. However, PAC response to ACTH in normal subjects controlled for modifiers of PAC has not been established. Our report includes two experiments. In both, subjects were studied in the morning and were in sodium (Na+) balance prior to study on 4 g Na+ for phase I, and 2 and 8 g Na+ diets for phase II. Na+ balance was established by 24-h urinary Na+ (UNa+) in phases I and II, and also by fractional excretion of Na+ (FENa+) in phase II. After being supine for 60 min, subjects received 0.25 mg of iv bolus ACTH. PAC, plasma renin activity and plasma potassium (K+) were drawn every 30 min in phase I and every 15 min in phase II. The rise in PAC (rPAC) and correlation coefficients were calculated. In phase I, peak PAC occurred at 30 min, 1130 +/- 420 pmol/L, with a rPAC of 810 +/- 310 pmol/L. Twenty-four hour UNa+ was 86 +/- 45 mmol/24 h. In phase II, time and magnitude of peak PAC and rPAC were dependent on diet. Both occurred at 30 min for 8 g Na+: peak PAC was 640 +/- 210 pmol/L and rPAC was 440 +/- 190 pmol/L; and at 60 min for 2 g Na+: peak PAC was 1040 +/- 320 pmol/L and rPAC was 690 +/- 220 pmol/L. Correlation coefficients for rPAC and 24-h UNa+ was r = -0.44, P less than 0.05 and for rPAC and FENa+ was r = -0.46, P less than 0.05. In summary, in subjects supine for 60 min prior to iv bolus ACTH, Na+ balance is the most important determinant of PAC response. Both magnitude and timing of rPAC is influenced by Na+ balance. Finally, both 24-h UNa+ and FENa+ are valid for establishing pretesting Na+ status.

Adrenal Gland Diseases↗
PubMed1992

Risk of hepatitis B and human immunodeficiency virus transmission to a patient from an infected surgeon due to percutaneous injury during an invasive procedure: estimates based on a model.

The objective was to estimate the probability of sporadic hepatitis B virus (HBV) and human immunodeficiency virus (HIV) transmission to a patient from an infected surgeon due to percutaneous injury during an invasive procedure. Risk was estimated based on a model involving three probabilities: A, the probability that the surgeon will sustain a percutaneous injury during an invasive procedure; B, the probability that the sharp object causing the injury and now contaminated with the surgeon's blood will contact the patient's wound; and C, the probability that infection would be transmitted to the patient after such an exposure. The probability of transmission during one procedure is p = A x B x C. The probability of transmission to at least one patient during N procedures is 1-(1-p)N. Values for A, B, and C were estimated from prospective studies. The estimated probability of transmission from an infected surgeon to a patient during a single procedure is 0.00024-0.0024% for HIV and 0.024-0.24% for HBV if the surgeon is positive for hepatitis B e antigen (HBeAg). The estimated probability of transmission to at least one patient during 3,500 procedures (estimated to be performed during an HIV-infected surgeon's remaining working life) is 0.81-8.1% for HIV; 57-100% for HBV if the surgeon is an HBeAg carrier. These estimates represent population averages and may not necessarily apply to a particular procedure performed by a particular surgeon, for which the risk may be considerably lower or higher than the estimated average. This risk assessment, which is based on limited data and does not take clusters of transmission into account, predicts that the risk of sporadic HBV transmission from infected surgeons to patients due to percutaneous injury during an invasive procedure is small and that the risk of HIV transmission is less than that for HBV. More data are needed to understand both sporadic and epidemic transmission in order to further reduce patient risk.

Carrier State↗
PubMed1992

Inhibition of interleukin-5 gene expression by dexamethasone.

The effect of glucocorticoids on interleukin-5 (IL-5) gene expression was assessed in human peripheral blood mononuclear cells. IL-5 expression was stimulated by phytohaemagglutinin (PHA), IL-2, phorbol myristate acetate (PMA) or Ionomycin. A semi-quantitative assay for IL-5 gene expression was developed, based on RNA extraction and the polymerase chain reaction. IL-5 expression in response to PHA was profoundly inhibited by 10(-6) M dexamethasone, and significant inhibition was detected at doses of dexamethasone as low as 10(-9) M. When dexamethasone was added to the cells at the same time as PHA, the inhibitory effect could be detected as early as 3 hr. Dexamethasone at 10(-6) M also profoundly inhibited the IL-5 response to PMA and to IL-2, but the IL-5 response to Ionomycin was not significantly affected. These results suggest that dexamethasone may be capable of interfering with a pathway involving protein kinase C. There is increasing evidence that IL-5 may play a pathogenic role in asthma and other manifestations of acute hypersensitivity. The present findings indicate that inhibition of IL-5 expression may be one of the mechanisms whereby glucocorticoids exert their beneficial effects in diseases such as asthma.

Base Sequence↗
PubMed1991

The National Nosocomial Infections Surveillance System: plans for the 1990s and beyond.

The National Nosocomial Infections Surveillance (NNIS) System is an ongoing collaborative surveillance system among the Centers for Disease Control (CDC) and United States hospitals to obtain national data on nosocomial infections. This system provides comparative data for hospitals and can be used to identify changes in infection sites, risk factors, and pathogens, and develop efficient surveillance methods. Data are collected prospectively using four surveillance components: hospital-wide, intensive care unit, high-risk nursery, and surgical patient. The limitations of NNIS data include the variability in case-finding methods, infrequency or unavailability of culturing, and lack of consistent methods for post-discharge surveillance. Future plans include more routine feedback of data, studies on the validity of NNIS data, new components, a NNIS consultant group, and more rapid data exchange with NNIS hospitals. Increasing the number of NNIS hospitals and cooperating with other agencies to exchange data may allow NNIS data to be used better for generating benchmark nosocomial infection rates. The NNIS system will continue to evolve as it seeks to find more effective and efficient ways to measure the nosocomial infection experience and assess the influence of patient risk, changes in the delivery of hospital care, and changes in infection control practices on these measures.

Centers for Disease Control and Prevention, U.S.↗
PubMed1991

Nosocomial infection rates in adult and pediatric intensive care units in the United States. National Nosocomial Infections Surveillance System.

To determine which intensive care unit (ICU) infection rate may be best for interhospital and intrahospital comparisons and to assess the influence of invasive devices and type of ICU on infection rates, we analyzed data from the National Nosocomial Infections Surveillance System. From October 1986 to December 1990, 79 hospitals reported 2,334 hospital-months of data from 196 hospital units. The median overall infection rate was 9.2 infections per 100 patients. However, this infection rate had a strong positive correlation with average length of ICU stay (r = 0.60, p less than 0.0001). When patient-days was used in the denominator, the median overall nosocomial infection rate was 23.7 infections per 1,000 patient-days. Although there was a marked reduction in the correlation with average length of stay, this rate had a strong positive correlation with device utilization (r = 0.59, p less than 0.0001). To attempt to control for average length of stay and device utilization, we examined device-associated nosocomial infection rates. Central line-associated bloodstream infection rates, catheter-associated urinary tract infection rates, and ventilator-associated pneumonia rates varied by ICU type. The distributions of device-associated infection rates were different between some ICU types and were not different between others (coronary and medical ICUs or medical-surgical and surgical ICUs). Comparison of device-associated infection rates and overall device utilization identified hospital units with outlier infection rates or device utilization. These data show that: (1) choice of denominator is critical when calculating ICU infection rates; (2) device-associated infection rates vary by ICU type; and (3) intrahospital and interhospital comparison of ICU infection rates may best be made by comparing ICU-type specific, device-associated infection rates.

Adult↗
PubMed1991

Reassessment of the association between Guillain-Barré syndrome and receipt of swine influenza vaccine in 1976-1977: results of a two-state study. Expert Neurology Group.

Although the original Centers for Disease Control study of the relation between A/New Jersey/8/76 (swine flu) vaccine and Guillain-Barré syndrome (polyradiculoneuritis) demonstrated a statistical association and suggested a causal relation between the two events, controversy has persisted. To reassess this association, the authors obtained medical records of all previously reported adult patients with Guillain-Barré syndrome in Michigan and Minnesota from October 1, 1976 through January 31, 1977. To identify previously unreported hospitalized cases with onset of symptoms during this period, the authors surveyed medical care facilities. A group of expert neurologists formulated diagnostic criteria for Guillain-Barré syndrome and then reviewed the clinical records in a blinded fashion. Of the 98 adult patients from the original Centers for Disease Control study eligible for consideration, three were found to have been misclassified by date of onset and were excluded. Of the remaining 95, the 28 (29%) who did not meet the diagnostic criteria were equally distributed between the vaccinated group (18 of 60, 30%) and the unvaccinated group (10 of 35, 29%). In addition to the 67 remaining cases who met the diagnostic criteria, six previously unreported cases (three of whom had been vaccinated) were found and included in this analysis. The relative risk of developing Guillain-Barré syndrome in the vaccinated population of these two states during the 6 weeks following vaccination was 7.10, comparable to the relative risk of 7.60 found in the original study. These findings suggest that there was an increased risk of developing Guillain-Barré syndrome during the 6 weeks following vaccination in adults. The excess cases of Guillain-Barré syndrome during the first 6 weeks attributed to the vaccine was 8.6 per million vaccinees in Michigan and 9.7 per million vaccinees in Minnesota. No increase in relative risk for Guillain-Barré syndrome was noted beyond 6 weeks after vaccination.

Causality↗