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Biomedical subjects

W Freeman

Publications and source records attributed to W Freeman.

At least 19 recordsLinked to original sources
PubMed1997

Indocyanine green angiography of the peripapillary region in glaucomatous eyes by confocal scanning laser ophthalmoscopy.

PURPOSE: To investigate the peripapillary region in glaucomatous eyes by indocyanine green angiography. METHODS: Indocyanine green angiography of the optic disk and peripapillary region was evaluated by modified confocal scanning laser ophthalmoscopy in 22 eyes of 22 patients with glaucoma and in 10 normal eyes of 10 control patients with unilateral choroidal melanoma. The occurrence and extent of indocyanine green angiographic anomalies were correlated with optic disk morphology and the severity of glaucoma. RESULTS: In the 32 eyes of 32 patients, two types of peripapillary defects were identified in the late-phase angiograms. The first was hypofluorescent areas in the peripapillary region and was more common in eyes with glaucoma (P < .02); their occurrence and extent correlated with age (P < .01). In nine of the 17 eyes, alpha (peripheral) zone peripapillary atrophy corresponded with the areas of peripapillary indocyanine green hypofluorescene. The second defect, hypofluorescent halos adjacent to and extending around the full circumference of the optic disk margins, did not correlate with any of the study factors. CONCLUSIONS: Indocyanine green angiography showed areas of hypofluorescene in the peripapillary region in late-phase angiograms in 68% of glaucomatous eyes compared with 20% of control eyes. These hypofluorescent areas might be either of result of blockage of background fluorescence by pigment or caused by an absence of vascular tissue (choriocapillaris).

Adult↗
PubMed1996

Congenital cystic disease of the liver, pancreas, and kidney in a nubian goat (Capra hircus).

A congenital cystic disease of the liver, pancreas, and kidney was diagnosed in a 3-week-old female Nubian goat (Capra hircus). Gross and histologic features were similar to autosomal recessive polycystic kidney disease in humans and to previous reports of juvenile polycystic disorders in several animal species. Grossly, the lesions were confined to the liver and pancreas. The liver was severely enlarged and contained multiple fluid-filled cysts of various sizes. There was tortuous ectasia of the extrahepatic bile ducts. In the pancreas, multiple small cysts were disseminated throughout the parenchyma. Histologically, there was cavernous ectasia of the intra- and extrahepatic biliary system. Dilated intrahepatic biliary channels formed a branching and anastomosing pattern throughout the hepatic parenchyma and were often bordered by fibrous connective tissue. The pancreas had dilation of intra- and interlobular ducts. Renal cortical tubules and collecting ducts were ectatic. Congenital polycystic disorder has not been documented previously in the goat.

Animals↗
PubMed1994

Combination of ganciclovir and granulocyte-macrophage colony-stimulating factor in the treatment of cytomegalovirus retinitis in AIDS patients. The ACTG 073 Team.

The efficacy and safety of a combination of ganciclovir plus GM-CSF was evaluated in AIDS patients with cytomegalovirus retinitis. In phase A, patients were randomized to receive ganciclovir, 5 mg/kg every 12 h for 14 days followed by 5 mg/kg daily, with (n = 24) or without (n = 29) GM-CSF (1-8 micrograms/kg daily subcutaneously) to maintain absolute neutrophil counts between 2500 and 5000 cells/microliters. In phase B, after 16 weeks zidovudine was added to the regimen of 16 patients receiving ganciclovir plus GM-CSF and 20 receiving ganciclovir alone. At this stage, GM-CSF was added to the treatment protocol of any patient receiving ganciclovir plus zidovudine who became neutropenic. In phase A, patients in the ganciclovir plus GM-CSF group had significantly higher neutrophil counts than ganciclovir-alone patients (p = 0.0001). Overall, 12.5% of patients treated with GM-CSF developed neutropenia (absolute neutrophil counts < 500/microliters phase A and < 750/microliters phase B) compared with 45% of patients treated without GM-CSF. GM-CSF patients missed 10 of a possible 4705 scheduled doses of ganciclovir compared with 34 missed doses of a possible 6584 in the ganciclovir-alone group (p = 0.011). There was a trend, although not statistically significant, for patients in the GM-CSF group to experience delayed progression of their retinitis.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS-Related Opportunistic Infections↗
PubMed1994

Rates of change in peak expiratory flow and in diurnal variation in peak flow in patients recovering from acute severe asthma.

1. The rates of change in mean peak expiratory flow and in diurnal variation in peak flow were compared in 14 patients recovering from acute severe asthma. 2. Peak expiratory flow was measured on hospital admission, and at 6-hourly intervals for the next 3 weeks. 3. Diurnal variation in peak flow was assessed by measuring the following: amplitude (the highest minus the lowest peak expiratory flow during any given 24 h period), amplitude % mean (the highest minus the lowest peak expiratory flow during any given 24 h period divided by the mean peak expiratory flow over that period) and residual amplitude (the maximum variation about the mean peak expiratory flow during any given 24 h period). 4. Plots of diurnal variation in peak flow and peak expiratory flow against time were constructed for each patient. To enable comparison of changes in peak expiratory flow and diurnal variation in peak flow the data were transformed. 5. The rate of change for mean peak expiratory flow and for the three measures of diurnal variation in peak flow was assessed by fitting an exponential function to each set of data, and calculating the slope of the exponential curve halfway through the period of observation (10.5 days). 6. Median (range) slope for peak expiratory flow was 0.055 (0-2.57). The comparable value for amplitude was -3.15 (-1.27 to -4.22) (absolute median values compared, P = 0.0029), for amplitude % mean was -1.87 (-0.18 to -5.95) (P = 0.012) and for residual amplitude was -1.43 (-0.62 to -3.09) (P = 0.033).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1993

Endurance exercise capacity in adults with cystic fibrosis.

We have compared the maximal and endurance exercise capacities in 22 (15 male) adult cystic fibrosis (CF) patients with a resting oxygen saturation (SaO2) > or = 90%, with age and sex matched controls (CON). The maximum oxygen uptake (VO2max) and heart-rate were lower for the CF group whereas the maximum ventilation reached a higher percentage of predicted. Furthermore, for the CF group there was a relationship between the % predicted VO2max and measures of lung function, confirming a ventilatory limit to maximum exercise in patients with more severe disease and a near normal maximum exercise capacity in those with mild disease. Endurance capacity, defined as the duration of exercise at 80% of each individuals VO2max, was however similar for the two groups [CF: 22.21 (15.82) vs. CON: 24.94 (13.05) min]; despite the CF group exercising under less efficient ventilatory conditions. Endurance capacity was not related to the measurements of lung function. Of the seven CF patients desaturating at maximal exercise (SaO2 < 90%), five desaturated at a work load of 80% VO2max, whereas only one desaturated at 50% VO2max. This study confirms that with increasing severity of disease, maximal exercise capacity may be limited in adult CF patients, whereas endurance capacity (at the same relative work load) is unimpaired. Furthermore, CF patients who desaturate during a progressive maximal exercise test are likely to desaturate during constant work load exercise if the intensity is high but unlikely to do so if the intensity is low. The information from these exercise tests would be of value for prescribing individual training programmes and for evaluating the effects.

Adolescent↗
PubMed1993

Prevalence of diagnosed diabetes among American Indians and Alaska Natives, 1987. Estimates from a national outpatient data base.

OBJECTIVE: To estimate the prevalence of diagnosed diabetes among American Indians and Alaska Natives served by the IHS. RESEARCH DESIGN AND METHODS: This was a cross-sectional study of the 1987 IHS national outpatient data base. RESULTS: Prevalence rates of diagnosed diabetes determined from the IHS outpatient data base were consistent with recent studies of diabetes in different IHS areas. IHS-wide, age-adjusted prevalence was 69/100,000, or 2.8 times the U.S. rate. There was considerable variation in prevalence rates of diabetes throughout the country, with rates ranging from 15.3/100,000 in Alaska to 119.2/100,000 in southern Arizona. CONCLUSIONS: This study documented the high prevalence of diabetes among American Indians and Alaska Natives and the wide variation in rates between different tribal groups. This study also demonstrated the feasibility of using an outpatient data base to estimate rates of disease that have uniform methods of diagnosis and result in frequent clinic visits.

Age Factors↗
PubMed1992

The effect of ipratropium bromide on maximal exercise capacity in asthmatic and non-asthmatic men.

The effect of 0.5 mg nebulized ipratropium bromide (IB) on the cardio-respiratory responses to a progressive maximal cycle exercise test was compared with a matched placebo (P) in eight mild asthmatic and eight non-asthmatic men. The forced expiratory volume in l s (FEV1) in the asthmatic group was higher after ipratropium bromide both at rest [IB, mean 4.07 (SD 1.18) l versus P, 3.83 (1.29) l, P less than 0.05] and after exercise [IB, 3.64 (1.31) l versus P, 3.30 (1.40) l, P less than 0.02]. Since the percentage fall in the FEV1 after exercise was not significantly changed by ipratropium bromide [IB, -12 (11)% versus P, -16 (14)%], the improvement in the post-exercise FEV1 in the asthmatic group is attributable to the pre-exercise bronchodilatation. The resting and post-exercise FEV1 in the non-asthmatic group were also significantly higher after ipratropium bromide. However, neither group showed any differences in the cardio-respiratory, haemodynamic or subjective responses to the progressive maximum exercise test when ipratropium bromide was compared with placebo. These results demonstrate the absence of significant cardio-respiratory effects during exercise with this relatively high dose of ipratropium bromide, in patients with mild asthma and in non-asthmatic subjects. No ergogenic effect on maximal exercise performance was shown to question its use by asthmatic athletes engaged in high level competition.

Adult↗
PubMed1991

A multicenter study of Pneumocystis choroidopathy.

We studied 21 patients with the acquired immunodeficiency syndrome and presumed Pneumocystic carinii choroidopathy. The lesions were characteristically yellow to pale yellow in color, appeared at the level of the choroid, and were found in the posterior pole. They varied in size from 300 to 3,000 microns, initially increasing in number before treatment and eventually resolving after systemic antimicrobial therapy. Of the 21 patients, 18 (86%) had received inhaled pentamidine as prophylaxis against Pneumocystis pneumonia. Visual acuity and visual field testing showed little evidence of retinal destruction. Survival after the diagnosis of the choroidopathy ranged from two to 36 weeks. Pneumocystic choroidopathy offers an easily accessible clue to disseminated Pneumocystis infection. When comparing drugs for Pneumocystis prophylaxis, careful ocular examination can provide one indicator of the relative efficacy of protection against extrapulmonary disease.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Cardio-respiratory responses to exercise following treatment of acute severe asthma.

Asthmatic patients are encouraged to adopt a normal and active life-style. However, following treatment of acute severe asthma, patients may ask for advice about taking exercise. Serial measurements of the cardio-respiratory responses to continuous work load exercise, were made in asthmatic patients convalescing following hospital treatment of an acute exacerbation. Eighteen asymptomatic patients, (seven male) aged 18-48 years, were studied. The first test was performed within 1 week of admission, when the mean (SD) peak expiratory flow rate (PEFR) was 88 (20)% predicted normal and the arterial oxygen tension (PaO2) was 13.1 (1.4) kPa. No significant differences in the mean cardio-respiratory responses, from the last minute of exercise, were found during the 4-week study. There were no significant differences in the four tests, between the resting PEFR, lowest post-exercise PEFR or % change in PEFR. Also, there were no significant differences in the pre-exercise, end of exercise and recovery (10 min after exercise) PaO2, between the four tests. However, taking the four tests as a whole, significant relationships were found between the recovery PaO2 and the lowest post-exercise PEFR, expressed in absolute terms (r = 0.515, P less than 0.001), and as a percentage of predicted normal (r = 0.533, P less than 0.001); and also between the recovery PaO2 and the % change in PEFR after exercise (r = 0.299, P less than 0.05). It is suggested that a formal exercise test should be performed in convalescent asthmatics wishing to participate in active sports. Patients with exercise-induced asthma may then be identified and treated appropriately.

Acute Disease↗
PubMed1991

The effect of sustained-release theophylline in nocturnal asthma.

Nocturnal symptoms are common and often disabling in asthmatic subjects. Furthermore, they often persist, in spite of appropriate dosages of inhaled beta 2-agonists and topical steroids. In such a clinical situation, theophylline preparations may have a therapeutic role. This double-blind, placebo-controlled, cross-over trial was designed to evaluate the effectiveness of a twice-daily Bioavail slow-release theophylline capsule in a group of out-patient asthmatics, with a history of nocturnal and/or early morning wheeze or chest tightness. Theophylline was initially prescribed and monitored in an 'open' phase to obtain the drug dosage required to achieve a serum level in the therapeutic range of 10-20 mg/l. In the ten patients who completed the study, serum theophylline levels were stable throughout. During active treatment there was an improvement in morning peak expiratory flow rate (PEFR), and a reduction in measurements of diurnal variation. In addition, the bronchodilator response to an inhaled beta 2-agonist was preserved. Bioavail theophylline has thus been shown to be an effective agent in the management of adults with nocturnal asthma.

Adult↗
PubMed1990

The twenty-metre shuttle-running test: a combined test for maximal oxygen uptake and exercise-induced asthma?

A maximal multistage 'twenty-metre shuttle-running test' has already been developed to estimate maximal oxygen uptake (VO2 max). This field test requires little equipment or expertise, can be performed simultaneously by several subjects, and is widely used in physical education lessons. The present study assessed the potential for this test to provoke exercise-induced asthma in 73 schoolboys, aged 15-16 years. Measurements of the forced expiratory volume in one second (FEV1) were made at rest and 10 min after the twenty-metre shuttle-running test; exercise-induced asthma was defined as greater than a 10% fall in FEV1 after exercise. The pupils achieved 73 +/- 19 shuttles (mean +/- SD) giving a VO2 max of 47.0 +/- 5.3 ml kg-1 min-1. Exercise-induced asthma was documented in eight pupils (11%); two were known asthmatics who, despite taking pre-exercise B2 agonist treatment, had sharp falls in FEV1 (-25.4 and -25.6%); two had previously experienced occasional chest tightness or wheeze with exercise (-16.5 and -13.2% fall FEV1); but four were asymptomatic, with no previous asthmatic symptoms (-20.0, -18.2, -15.3 and -11.4% fall FEV1). This study has demonstrated the potential of the twenty-metre shuttle-running test to provoke exercise induced-asthma, and may therefore be a useful clinical test to assess for exercise-induced asthma when an estimate of VO2 max would also be helpful. Furthermore, physical education teachers should take basic precautions when using this test.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Endurance running performance in athletes with asthma.

Laboratory assessment was made during maximal and submaximal exercise on 16 endurance trained male runners with asthma (aged 35 +/- 9 years) (mean +/- S.D.). Eleven of these asthmatic athletes had recent performance times over a half-marathon, which were examined in light of the results from the laboratory tests. The maximum oxygen uptake (VO2max) of the group was 61.8 +/- 6.3 ml kg-1 min-1 and the maximum ventilation (VEmax) was 138.7 +/- 24.7 l min-1. These maximum cardio-respiratory responses to exercise were positively correlated to the degree of airflow obstruction, defined as the forced expiratory volume in 1 s (expressed as a percentage of predicted normal). The half-marathon performance times of 11 of the athletes ranged from those of recreational to elite runners (82.4 +/- 8.8 min, range 69-94). Race pace was correlated with VO2max (r = 0.863, P less than 0.01) but the highest correlation was with the running velocity at a blood lactate concentration of 2 mmol l-1 (r = 0.971, P less than 0.01). The asthmatic athletes utilized 82 +/- 4% VO2max during the half-marathon, which was correlated with the %VO2max at 2 mmol l-1 blood lactate (r = 0.817, P less than 0.01). The results of this study suggest that athletes with mild to moderate asthma can possess high VO2max values and can develop a high degree of endurance fitness, as defined by their ability to sustain a high percentage of VO2max over an endurance race. In athletes with more severe airflow obstruction, the maximum ventilation rate may be reduced and so VO2max may be impaired. The athletes in the present study have adapted to this limitation by being able to sustain a higher %VO2max before the accumulation of blood lactate, which is an advantage during an endurance race. Therefore, with appropriate training and medication, asthmatics can successfully participate in endurance running at a competitive level.

Adult↗
PubMed1990

Association between risk factors for coronary heart disease in schoolboys and adult mortality rates in the same localities.

Risk factors for coronary heart disease were compared in fifth year boys (15-16 years old) from two schools that were chosen from localities with a fourfold difference in adult mortality from coronary heart disease. One school was in an underprivileged urban locality in the area of increased incidence of heart disease ('high risk') and the other in a semi-rural affluent locality with an incidence of heart disease similar to the national average ('low risk'). Smoking, hypertension, hypercholesterolaemia, obesity, physical fitness, and inactivity were evaluated as risk factors for coronary heart disease. Smoking, increased body fat, poor diet, and physical inactivity were found increased among pupils from the school in the high risk area compared with those in the low risk area. Lipids, maximum oxygen uptake, and hypertension were similar in both schools. The risk of coronary heart disease seems to reflect the adult mortality rates in the area. To reduce the overall incidence of coronary heart disease, health education should be directed towards prevention of smoking, improving diets, and increasing amounts of activity among school children, with special attention directed toward children in regions where there is a high mortality from coronary heart disease among adults.

Adolescent↗
PubMed1990

Responses of asthmatic and non-asthmatic athletes to prolonged treadmill running.

Metabolic and cardio-respiratory responses of four asthmatic and four non-asthmatic athletes to two hours of treadmill running at 70 percent of maximal oxygen uptake are compared. The asthmatic group had pre-exercise airflow obstruction, as indicated by the lower forced expiratory volume in one second (FEV1) even after medication (2.90 +/- 0.661) compared to the non-asthmatic group (4.09 +/- 1.331). Changes in blood lactate, glucose and catecholamine concentrations as a result of the two hour run were similar for the two groups. However, the pattern of breathing was different. The asthmatics had a slower breathing frequency but a similar tidal volume to the non-asthmatics. Both groups had an increase in the ventilation rate over the two hour run. For the non-asthmatic group, this increase in ventilation was achieved by an increase in the breathing frequency (p less than 0.01), whereas tidal volume was reduced (p less than 0.05). The increase in the ventilation rate over the two hour run for the asthmatic group was brought about by a small increase in breathing frequency (p less than 0.05), whereas tidal volume was not changed. This maintenance of the tidal volume by the asthmatic athletes during endurance running may compensate for the airflow obstruction, and so allow successful participation in endurance running.

Adaptation, Physiological↗
PubMed1990

Effects of exercise on gas exchange in patients recovering from acute severe asthma.

The effect of exercise on gas exchange was studied in 17 patients (seven male and 10 female) recovering in hospital from acute severe asthma. On admission the patients (mean age 26 (SD 8) years) had a mean peak expiratory flow (PEF) of 26.8% (5.7%) predicted, a mean arterial oxygen tension (PaO2) of 8.63 (1.26) kPa, and a mean alveolar-arterial oxygen difference (A-aDO2) of 5.98 (1.34) kPa. Once resting symptoms had resolved (after 3.7 (1.6) days) patients performed a constant load exercise test (100 watts for men, 75 watts for women) on a bicycle ergometer for five minutes. PEF was measured before exercise and at five minute intervals for 30 minutes after exercise. Blood gas tensions were measured on capillary blood before, during, and 10 minutes after exercise. Treatment was not interrupted for this study. Mean PEF at rest was 87.6% (21.1%) predicted and showed no significant change after exercise. Mean PaO2 was 13.13 (1.37) kPa before exercise; it showed no significant change during exercise (13.93 (1.34) kPa) or 10 minutes after exercise (13.50 (2.15) kPa). Mean A-aDO2 also showed no change, being 1.82 (1.31) kPa before exercise, 1.79 (1.27) kPa during exercise, and 2.53 (0.93) kPa after exercise. It is concluded that moderate exercise carried out shortly after treatment for acute severe asthma is unlikely to result in worsening gas exchange during or after exercise if resting PEF, PaO2 and A-aDO2 have attained normal or near normal values.

Acute Disease↗