Deficiencies of Vitamins in CAPD Patients: The Effect of Supplementation

Concentrations of the vitamins B₁, B₂, B₆, B₁₂, C, folic acid,A, E and ß-carotene were determined in blood and 24-hdialysate in 44 CAPD patients. Twenty-five of these patientswere studied during chronic treatment (mean 313 days, range60–1034 days). Nineteen patients were studied during training.In a longitudinal study, 11 patients were analysed again after77–507 (mean 238) days. In both patient groups a considerable portion of patients (11%–64%)had blood concentrations indicative of a deficiency of the vitaminsB₁, B₆, C and folic acid. The average concentrations of thesevitamins were normal in both groups. The only abnormal findingwas the mean EGOT activity being deficient in patients on chronictreatment. Mean concentrations of vitamin A were above normalin both groups. In the longitudinal study a significant increaseof vitamin B₂ and a decrease of vitamin B₆ in blood was found. When compared to 24-h excretion in normal urine, loss with 24-hdialysate was low for vitamin B₁, normal to relatively highfor vitamin B₂ and B₆, but extremely high for vitamin C andfolic acid. The vitamins B₁₂, A, E and carotenoids were hardlydetectable in the dialysate. In ten other patients the effect of daily supplementation with2 mg vitamin B₆, 100mg vitamin C and 400 µg folic acidwas analysed during a 16-week period. In all patients a significantincrease in blood concentrations was obtained. It is concludedthat these dosages were sufficient to maintain a normal statusof these vitamins in CAPD patients.     

Work-related injuries in minors

Since 1938, federal child labor laws have restricted employment of persons under 18 years old, in part to protect them from hazardous occupations. Workers' compensation claims reported to the Supplementary Data System of the Bureau of Labor Statistics were examined to define the current status of occupational injuries among minors. Data tapes from 1980 to 1983 were searched to identify all current claims for injuries and illnesses occurring in 1980 in persons under age 18. Injury rates were calculated using information about employment in 1979 available from the 1980 census. In the 24 states included in this study, 23,823 claims were reported for persons less than 18 years old. Of these claims, approximately 10% were from persons under age 16. Rates of injuries in 16- and 17 year olds were 12.6 per 100 full-time male workers and 6.6 per 100 full-time female workers. Serious injuries included fractures, dislocations, and amputations, accounting for 5.8%, 0.7%, and 0.6% of cases, respectively. California, the only state that coded whether injuries resulted in fatalities, reported 12 deaths in this age group. Machines and vehicles, many of which are restricted under child labor laws, accounted for 8.3% and 5.8% of claims. These data suggest that persons under age 18 years are not adequately protected from occupational injury. Further attention and, possibly, new preventive strategies are needed.     

A computerized approach to discipline-specific bibliographies in the allied health sciences

The traditional subject headings in Index Medicus and other standard indexes have frequently proved too broad for researchers in the allied health sciences. Therefore, the Physician Assistant Program at the University of Florida has developed a computerized bibliography program designed to expedite research by using a selected list of keywords as subject headings and subheadings tailored to the interests and concerns of the physician assistant profession. Each subject heading and subheading is translated into a numerical coding system that permits efficient data entry and rapid identification of items in the professional literature as well as reducing the incidence of operator error in data entry. The program can be used for review of the literature, curriculum design, identification of supplementary reading material for education courses, and identification of appropriate resources to enhance the study of the physician assistant profession. Through the development of discipline-specific keywords, the program can be tailored to the educational and research interests of any discipline in the allied health sciences or other educational fields.     

Zinc, copper, manganese, and iron balance of parenterally fed very low birth weight preterm infants receiving a trace element supplement

To evaluate a pediatric trace element supplement (Ped-El, Pharmacia) 18 metabolic balance studies were completed in 13 infants (mean birth weight 909 +/- 67 g, x +/- SEM; mean gestational age 27.2 +/- 1 weeks) who received total parenteral nutrition. The supplement supplied 40 micrograms/kg/day of zinc resulting in negative retention of 226 micrograms/kg/day. Copper infused at 20 micrograms/kg/day led to a positive retention of 8 micrograms/kg/day and an increase in serum Cu (p less than 0.05) not related to Cu intakes. Manganese infused at 40 micrograms/kg/day was nearly all retained (88 +/- 16% retention). Iron infused at 120 micrograms/kg/day led to a positive retention of 93 micrograms/kg/day. Although plasma ferritin and percent transferrin saturation were elevated, only plasma Fe values were correlated with Fe intake. This trace element supplement does not appear suitable for very low birth weight preterm infants.     

Prognostic significance of serum cholesterol in nursing home men

Serum cholesterol was measured in 129 men (average age 70.6; range 41-96) of a Veterans Administration Nursing Home, and was correlated with other items in an extensive clinical data base. Serum cholesterol was less than 150 mg/dl in 13% of the subjects, and was less than 160 mg/dl in 18%. Cholesterol greater than 280 mg/dl occurred in 8%. Serum cholesterol varied directly (p less than 0.02) with: body weight, serum albumin, serum total protein, serum sodium, ability to walk, and ability to feed oneself; and indirectly (p less than 0.02) with death rate, degree of functional dependence, and serum SGOT and LDH. Nursing home men with cholesterol less than 150 mg/dl had a death rate of 63% during the 14 months after the cholesterol analysis, compared to a death rate of 9% in men with cholesterol greater than 150 mg/dl (p less than 0.05). Death rate during the year after the analysis was 52% if cholesterol was below 160 mg/dl, compared to 7% if it was above this threshold (p less than 0.05).     

A human cell beryllium acute toxicity assay

A rapid, inexpensive beryllium acute toxicity assay using human erythrocyte ATP levels has been developed. The assay uses a photometric measurement of the luciferin-luciferase reaction in erythrocytes incubated in HEPES buffer with the tested toxicant. Incubation in HEPES significantly increases the sensitivity of erythrocytes to beryllium when compared to incubation in either plasma or physiological saline. After a one-hour incubation period in HEPES buffer and beryllium there is a loss of 50% of the erythrocyte ATP at 3 micrograms/ml of beryllium, and an 80% loss of ATP at 5 micrograms/ml of beryllium. The source of human erythrocytes does not appear to influence the test. Erythrocytes from 10 individuals, one with chronic beryllium disease and another with an acute sensitivity to beryllium, all gave similar biphasic dose-response curves to beryllium.     

ROLE OF NITRIC OXIDE IN THE CONTROL OF THE RENAL MEDULLARY CIRCULATION

1. Nitric oxide (NO) has been implicated as an important controller in the short- and long-term regulation of arterial pressure. Studies performed in our laboratory have demonstrated that chronic intravenous administration of the NO synthase inhibitor N^G-nitro-L-arginine methyl ester (L-NAME) selectively decreases renal medullary blood flow, causes sodium and water retention and leads to hypertension. 2. To determine the importance of the renal medullary effects in this model of hypertension, further studies were conducted to examine the influence of selective stimulation or inhibition of renal medullary NO on whole kidney function and cardiovascular homeostasis. With the use of a unique catheter to directly infuse into the renal medullary interstitial space, stimulation (bradykinin or acetylcholine) or inhibition (L-NAME) of renal medullary NO selectively increased or decreased renal medullary blood flow. 3. The changes in medullary flow in these experiments were associated with parallel changes in sodium and water excretion independent of alterations in renal cortical blood flow or glomerular filtration rate. 4. Studies were then undertaken to examine the long-term effects of selective NO inhibition in the renal medulla on cardiovascular homeostasis. Chronic infusion of L-NAME directly into the renal medullary interstitial space of uninephrectomized Sprague-Dawley rats led to a selective decrease in renal medullary blood flow that was sustained throughout the 5 day L-NAME infusion period. The decrease in medullary blood flow was associated with retention of sodium and the development of hypertension and the effects were reversible. 5. The data reviewed indicate that NO in the renal medulla has a powerful influence on fluid and electrolyte homeostasis and the control of blood pressure.