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Biomedical subjects

E A Ross

Publications and source records attributed to E A Ross.

18 recordsLinked to original sources
PubMed1992

Axial myopia in eyes with optic nerve hypoplasia.

Given that abnormal visual experience during post natal development interferes with emmetropization, we proposed that eyes with hypoplastic optic nerves were predisposed to the development of refractive errors. Six of 14 patients with unilateral optic nerve hypoplasia and 5 of 22 patients with bilateral involvement had at least 4 D of myopia. Nine of the 11 patients with asymmetric bilateral involvement had relative myopia in the eye with the more abnormal optic nerve; none of the patients with symmetric bilateral involvement had a significant interocular refractive difference. Analysis of axial length measurements obtained in 10 of the 11 patients with high myopia showed a significant increase in total axial length. The presumed normal eye of patients with unilateral involvement was significantly smaller than the mean value for age-adjusted normals. We suspect that visual input to the central nervous system is one of the feedback signals involved in the regulation of ocular growth.

Adolescent↗
PubMed1992

Prevalence and mortality rate of congestive heart failure in the United States.

OBJECTIVES: The study was designed to determine the prevalence and mortality rate of congestive heart failure in noninstitutionalized men and women in the U.S. BACKGROUND: Congestive heart failure is a serious condition with significant morbidity and mortality. Earlier epidemiologic descriptions of congestive heart failure were constructed from small surveys, limited data, hospital records or death certificates. No nationally representative data from noninstitutionalized persons have been examined. METHODS: Data collected from the National Health and Nutrition Examination Survey (NHANES-I, 1971 to 1975) were used to determine the prevalence of heart failure on the basis of both self-reporting and a clinical definition. Mortality data were derived from the NHANES-I Epidemiologic Follow-up Study (1982 to 1986). RESULTS: The prevalence of self-reported congestive heart failure approximates 1.1% of the noninstitutionalized U.S. adult population; the prevalence of congestive heart failure based on clinical criteria is 2%. These estimates suggest that between 1 and 2 million adults are affected. Mortality at 10 and 15 years for those persons with congestive heart failure increases in graded fashion with advancing age, with men more likely to die than women. In the group greater than or equal to 55 years old, the 15-year total mortality rate was 39.1% for women and 71.8% for men. CONCLUSIONS: Congestive heart failure is a common problem in the U.S., with significant prevalence and mortality, both of which increase with advancing age. As the population of the U.S. becomes older, the health care impact of congestive heart failure will probably grow.

Adult↗
PubMed1992

Effects of ascorbic acid and pyridoxine supplementation on oxalate metabolism in peritoneal dialysis patients.

We studied the effect of vitamin C and B6 supplementation on oxalate metabolism in seven patients receiving chronic peritoneal dialysis therapy. The study was divided into three phases, each lasting 4 weeks. Plasma oxalate, total ascorbic acid, and pyridoxal-5'-phosphate (PLP) were measured at the end of each phase. Twenty-four-hour urinary excretion and dialysate removal rates of oxalate were also obtained. At the end of phase I (supplement-free period), plasma oxalate levels were markedly elevated at 47.6 +/- 7.1 mumol/L (437 +/- 66 micrograms/dL) (normal, 3.4 +/- 0.4 mumol/L [30.3 +/- 1.6 micrograms/dL]). Plasma total ascorbic acid levels were 62 +/- 6 mumol/L (1.0 +/- 0.1 mg/dL) (normal, 45 to 57 mumol/L [0.8 to 1.0 mg/dL]), while plasma PLP levels were markedly reduced to 24 +/- 5 nmol/L (normal, 40 to 80 nmol/L). Daily supplements of 0.57 mmol (100 mg) ascorbic acid orally (phase II) resulted in a 19% increase in the plasma oxalate levels to 57.8 +/- 6.1 mumol/L (520 +/- 55 micrograms/dL) (P less than 0.03), with a concomitant 60% increase in the plasma ascorbate levels (91 +/- 6 mumol/L [1.6 +/- 0.1 mg/dL], P less than 0.01). Plasma PLP values remained low. Finally, during phase III (0.57 mmol or 100 mg ascorbic acid plus 59.6 mumol or 10 mg pyridoxine HCI orally daily), plasma oxalate levels declined by 17% to 47.9 +/- 5.2 mumol/L (431 +/- 47 micrograms/dL) (P greater than 0.05 v phase II).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Ascorbic acid supplements in patients receiving chronic peritoneal dialysis.

Ascorbic acid supplements are commonly prescribed to patients with end-stage renal disease receiving peritoneal dialysis. To establish the need for ascorbic acid supplements, we evaluated seven chronic peritoneal dialysis patients during a supplement-free (phase I) period, and while receiving oral ascorbic acid (0.57 mmol/d [100 mg/d]) (phase II). Because of a proposed interaction with vitamin B6, patients were additionally supplemented with pyridoxine HCl (59.6 mumol/d [10 mg/d]) (phase III). Plasma levels and dialysate removal rates of total ascorbic acid and plasma pyridoxal-5-phosphate (PLP) were measured at the end of each phase. During phase I, plasma ascorbic acid levels (normal, 45 to 57 mumol/L [0.8 to 1.0 mg/dL]) declined slightly from 74 +/- 11 mumol/L (1.3 +/- 0.2 mg/dL) to 62 +/- 11 mumol/L (1.1 +/- 0.2 mg/dL) (P less than 0.02) at the end of the third week, and then remained stable to the end of the fourth week. Plasma ascorbic acid levels were no different in patients with or without residual renal function. With the addition of vitamin C supplements, plasma ascorbic acid levels increased by 45% of the baseline value at the end of phases II (P less than 0.001). The dialysate removal rate of ascorbic acid was 0.28 +/- 0.03 mmol/d (50 +/- 6 mg/d) at the end of phase I, and increased by 57% of the baseline value at the end of phases II (P less than 0.001). However, the peritoneal clearance of ascorbic acid remained unchanged during all phases the study. Pyridoxine depletion or repletion had no effect on plasma ascorbic acid levels (P greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Behavioral interventions to increase adherence in colorectal cancer screening.

This investigation was a randomized controlled trial to determine the impact of health education interventions on the return of mailed fecal occult blood (FOB) tests (FOBT adherence) in a colorectal cancer screening program. The study sample included 2,201 men and women aged 50 to 74 years who were members of an Independent Practice Association (IPA)-type health maintenance organization (HMO). Subjects were randomly assigned to a "usual care" Control Group (advance letter, screening kit, reminder letter), and Treatment Groups 1 (usual care + reminder call), 2 (usual care + self-held screening booklet + reminder call), or 3 (usual care + self-held screening booklet + instruction call + reminder call). Bivariate analysis revealed significant differences in adherence (P less than .001) across study groups: Control Group (27%), Group 1 (37%), Group 2 (37%), Group 3 (48%). In addition, a significant positive association between age and adherence (P less than .001) was found. Logistic regression analysis revealed an interaction between sex and treatment. Adherence among men in all treatment groups increased significantly (P less than .0001) in relation to Control Group males. Men in Group 3 also were more likely to adhere than those in Group 2 (P less than .01) or Group 1 (P less than .01). Among women, adherence was significantly higher in Group 3 than in Group 2 (P less than .03), Group 1 (P less than .025), or the Control Group (P = .0008). The primary reason cited for nonadherence was perceived inconvenience of the FOB testing procedure.

Aged↗
PubMed1990

Oxygen supplementation during exercise in cystic fibrosis.

Fourteen female and 22 male patients with cystic fibrosis (CF), 8 to 29 yr of age, performed two progressive exercise tests to exhaustion on a cycle ergometer, breathing normoxic air (21% O2) for one test, and hyperoxic air (30% O2) for the other test. The order of gas administration was randomized. Minute ventilation (VE), oxygen uptake (VO2), end-tidal CO2 tension (PETCO2), work rate, oxyhemoglobin saturation (SAO2), and heart rate (HR) were measured throughout the tests. The SaO2 of 11 patients at peak exercise was 90% or less ("Low Sat" group). The SaO2 of 23 patients remained above 90% throughout the exercise ("High Sat" group). Hyperoxic air minimized desaturation during exercise in the Low Sat group to 2 +/- 2% compared to a decrease of 10 +/- 5% with normoxic air. The decrease in saturation was not significant for the High Sat group (1 +/- 1% for both 21% and 30% O2). Peak work rate and VO2 did not differ significantly between normoxic and hyperoxic conditions. However, VE and HR at peak exercise tended to be lower, and PETCO2 was higher during peak exercise with 30% O2 than 21% O2 for both groups. During submaximal exercise, O2 desaturation was diminished and HR was significantly lower with supplemental O2, specifically in the Low Sat group. VE was significantly lower for both groups during submaximal exercise with hyperoxic air. The results suggest that O2 supplementation minimizes O2 desaturation and enables patients with CF to exercise with reduced ventilatory and cardiovascular work.

Adolescent↗
PubMed1990

Quality of well-being before and after antibiotic treatment of pulmonary exacerbation in patients with cystic fibrosis.

General quality of life has only recently been measured with an objective tool in patients with cystic fibrosis (CF), and there have been no reported attempts to document changes in patients' overall well-being over time, as patients deteriorate or respond to intervention. We applied the Quality of Well-Being scale (QWB) in 28 patients with CF before and after a two-week course of oral ciprofloxacin used to treat pulmonary exacerbations. There were significant correlations between changes in QWB and various pulmonary function test results; QWB vs FEV1: r = 0.4, p less than 0.03; QWB vs FVC: r = 0.5, p less than 0.01; and QWB vs SaO2: r = 0.4, p less than 0.05. Thus, the QWB can track changes in general well-being in CF patients over a brief time and detect changes associated with pulmonary exacerbation and its treatment.

Attitude to Health↗
PubMed1990

Peritoneal leucocyte response to bacterial peritonitis in patients receiving peritoneal dialysis.

We evaluated the quantitative peritoneal leucocyte response to antibiotic therapy in 25 CAPD patients with 57 episodes of bacterial peritonitis. Eighty-eight percent of the peritonitis episodes were initially treated with a first generation cephalosporin, but results of microbial sensitivity studies led to a change in the initial antibiotic regimen in 23 episodes. Overall, 47/57 (82%) episodes were cured by antibiotic therapy alone (responders), while 10/57 (18%) required removal of the peritoneal catheter as a curative procedure (nonresponder). Neither the duration of symptoms on initial presentation nor the status of being a nonresponder could be related to the baseline peritoneal leucocyte values, either the total (PLC) or polymorphonuclear counts (PMN). Since the baseline PLC and PMN showed a 500-fold variation, subsequent changes were expressed as a percent [PLC (%) and PMN-PLC (%)] of the baseline value. On day 3 of peritonitis, PLC (%) and PMN-PLC (%) were less in responders (26% and 10%) than nonresponders (251% and 254%) (p less than 0.001). Differentiation between responders and nonresponders based on PLC (%) and PMN-PLC (%) was associated with a high degree of sensitivity (90%) and specificity (90%). Similar results were obtained for day 4. These data suggest that the temporal pattern of PLC and PMN, when expressed as a percentage of the baseline value, may be useful in predicting those episodes of peritonitis which require removal of the peritoneal catheter.

Adult↗
PubMed1989

Complex microphthalmos.

Forty patients were diagnosed as having complex microphthalmos on the basis of a malformed globe with a total axial length measurement at least 2 SDs below the mean for age-similar controls. Three had anterior segment dysgenesis; 4, congenital lens abnormalities; 14, chorioretinal colobomas; 12, persistent hyperplastic primary vitreous; 4, retinal dysplasia; and 3, complex malformations due to ipsilateral facial malformations. Measurements of total axial length indicated that complex microphthalmos was congenital and that postnatal growth of the malformed eye was similar to that of normal eyes. In most patients the anterior segment length was normal, while in all patients the posterior segment length was at least 2 SDs below the mean. Corneal diameter correlated significantly with total axial length (r2 = .57) and decreased linearly as total axial length decreased. In most patients in whom measurements were obtained, the lens and corneal power were increased, thereby compensating for decreased total axial length. We propose that inadequate production of secondary vitreous is the cause of the microphthalmos, given that the posterior segment was disproportionately reduced in size and the secondary vitreous is its predominant component. Evidence that each of the various ocular malformations can influence the production of secondary vitreous is presented.

Abnormalities, Multiple↗
PubMed1989

Simple microphthalmos.

Simple microphthalmos was diagnosed in 22 patients on the basis of a normal-appearing eye and a total axial length at least 2 SDs below the mean for age. Anterior segment length was normal in most patients while posterior segment length was at least 2 SDs below the mean in all patients, indicating that disproportionate reduction in posterior segment length accounted for the microphthalmos. The normal values for total axial length, anterior segment length, and posterior segment length were determined from the analysis of axial length measurements obtained from age-similar controls. Ten patients had isolated microphthalmos. One of them was diagnosed as having nanophthalmos on the basis of microcornea, total axial length less than 18 mm, and absence of systemic disease. Twelve patients had associated systemic disorders, such as fetal alcohol syndrome, myotonic dystrophy, and achondroplasia, which implicated decreased size of the optic cup, altered vitreous proteoglycans, low intraocular pressure, and abnormal release of growth factors in the pathogenesis of microphthalmos.

Adult↗
PubMed1989

Bullous pemphigoid-associated nephropathy: report of two cases and review of the literature.

Bullous pemphigoid has previously been reported in association with a variety of renal lesions. Two additional cases are presented in this report in which the nephropathy preceded the onset of the skin disease: one case with membranous glomerulopathy and one case of renal allograft rejection with concurrent membranous pathology. Both patients had positive immunofluorescence of the skin, typical of bullous pemphigoid. Institution of systemic corticosteroid therapy resulted in a satisfactory clinical response and cessation of the blistering process. These cases and a review of the literature suggest that the occurrence of an immune process involving these two different basement membranes is not merely coincidental. Many cases have been described in which the severity of the skin lesions paralleled that of the renal disease. Although the possibility of multiple distinct autoimmune processes cannot be excluded, anti-basement-zone antibody interactions or allograft rejection-induced immune stimulation are possible unifying mechanisms for the simultaneous skin and renal involvement observed in these two cases.

Adult↗
PubMed1989

Vitamin B6 requirements of patients on chronic peritoneal dialysis.

Patients with chronic renal failure often develop vitamin B6 deficiency, which is of clinical concern because the multiorgan system manifestations are similar to those of uremia. Vitamin B6 deficiency in hemodialysis patients has been previously studied, but the need for daily pyridoxine supplementation in patients on chronic peritoneal dialysis (CPD) remains unclear. Therefore, we studied a group of 11 stable patients, nine on CAPD and two CCPD, to test for vitamin B6 deficiency and to establish daily requirements. Adequacy of vitamin B6 nutrition was assessed by measurement of plasma and dialysate effluent total vitamin B6 and pyridoxal 5'-phosphate (PLP), the latter using a very sensitive modification of the tyrosine apodecarboxylase enzyme assay. After four weeks without vitamin B6 supplements on a diet containing 1.3 +/- 0.2 mg vitamin B6/day (7.7 +/- 1.2 mumol/day), all patients had subnormal plasma PLP levels, 16 +/- 3 nmol/liter (nml 40 to 60), seven having a severe deficiency (less than or equal to 20 nmol/liter). Plasma total vitamin B6 levels (which includes non-PLP forms of the vitamin) were normal in all patients at baseline, 116 +/- 29 nmol/liter. Peritoneal losses were small, 8 +/- 2 nmol PLP/day and 545 +/- 61 nmol total vitamin B6/day. Supplementation with 5 mg/day oral pyrodoxine HCl for up to 16 weeks adequately repleted eight patients (65 +/- 7 nmol PLP/L), while three patients required 10 mg/day to achieve normal plasma PLP levels. During three episodes of peritonitis, dialysate losses of PLP did not increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The quality of well-being in cystic fibrosis.

Traditional outcome measures in CF include PFTs, exercise tests, and several scoring systems that depend on pulmonary status and are largely subjective. The Quality of Well-being scale (QWB) is a widely used tool for measuring quality of life by three subscales: mobility, physical activity, and social activity, with points assigned within each subscale. The QWB has been shown to be valid in patients with COPD. We administered the QWB scale to 44 patients with CF, aged 7 to 36 years, and examined the relationship between QWB and PFTs, and in 15 patients the QWB vs exercise performance (peak VO2) on a progressive cycle ergometer test. QWB was significantly correlated with each variable examined: QWB vs FEV1, r = 0.5518 (p less than .0001); QWB vs FEF25-75%, r = 0.4793 (p less than .001); QWB vs PEFR, r = 0.4018 (p less than .01); QWB vs peak VO2, r = 0.5778 (p less than .01). The QWB scale is an objective measure that is significantly correlated with measures of performance and pulmonary function in CF. The relationship is not one of identity; further, the QWB is broad based and takes into account general well-being, not just pulmonary health, adding an important dimension to the care of patients with CF.

Activities of Daily Living↗
PubMed1987

The plasma creatinine concentration is not an accurate reflection of the glomerular filtration rate in stable renal transplant patients receiving cyclosporine.

We studied 31 stable renal cadaver kidney transplant patients receiving cyclosporine (CyA) and prednisone for immunosuppression to determine what reduction in true glomerular filtration rate (GFR) was reflected by their mild elevation in plasma creatinine concentration (1.8 +/- 0.11 mg/dL). We measured both the creatinine clearance (60 +/- 4.32 mL/min/1.73 m2) and the true GFR using Technetium 99m-DTPA (44 +/- 2.72 mL/min/1.73 m2). The creatinine clearance overestimated true GRF by a mean of 38%, indicating that this percentage of creatinine reached the urine by tubular secretion rather than glomerular filtration. A similar degree of overestimation was found in a separate group of 14 patients receiving imuran for immunosuppression. In 23 patients receiving CyA in whom the serum creatinine concentration was less than 2.0 mg/dL, the mean DTPA clearance was 49.5 +/- 2.83 mL/min/1.73 m2. In stable renal transplant patients receiving CyA, a serum creatinine concentration at, or close to, the upper limit of the normal range may reflect markedly impaired renal function.

Adult↗
PubMed1987

Pulmonary leukosequestration without hypoxemia during hemodialysis.

Dialysis-associated hypoxemia is frequently of clinically significant magnitude and is incompletely understood. In order to investigate the hypoxemia directly we labelled a patient's white blood cells with 111Indium-oxine prior to hemodialysis with acetate or bicarbonate baths. Both dialysate buffers were associated with similar degrees of early peripheral neutropenia, complement activation and elevation of lactoferrin levels, with simultaneous lung localization of radionuclide activity. However, there was not widening of the alveolar to arterial oxygen gradient, or increased wasted ventilatory fraction during this early time period. Significant hypoxemia occurred later in the dialysis, was associated with a decreased respiratory exchange ratio and only occurred with the acetate dialysate buffer. Thus, initial pulmonary leukosequestration was documented but did not have an adverse impact on gas exchange. Hypoxemia during acetate dialysis occurred instead as a consequence of alveolar hypoventilation.

Humans↗
PubMed1975

Differntiation of primary from secondary varicose veins by Doppler ultrasound and strain gauge plethysmography.

The Doppler ultrasonic velocity detector and the strain gauge plethysmograph were used to differentiate qualitatively and quantitatively primary from secondary varicose veins. Studies were performed in 21 limbs of 14 normal persons, nine limbs of eight patients with varices secondary to deep venous disease. The latter group of patients was identified by ultrasonic evidence of venous reflux through imcompetent deep venous valves. There was no significant difference in the maximum venous outflow of the limbs of the three groups of persons as determined by plethysmography. The primary hemodynamic abnormality in patients with varicose veins was significant venous reflux through imcompetent venous valves. This reflux was obliterated by tourniquet compression of the varices in patients with primary varicose veins. However, secondary varicose veins are distinguished by persistent abnormal deep venous reflux after compression of the varices. These diagnostic techniques not only provide accurate noninvasive diagnostic information but also may facilitate determination of prognosis and therapy of patients with varicose veins.

Adult↗