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R Ballard

Publications and source records attributed to R Ballard.

At least 37 records · Page 2Linked to original sources
PubMed1992

Short forms of the Marlowe-Crowne Social Desirability Scale.

Three short forms of the Marlowe-Crowne Social Desirability Scale were constructed from the results of principal components analysis (N = 399). Those subscales were compared with short forms developed by previous researchers who used the same methodology. Examination of the subscales indicated that 13 of the scale's 33 items were isolated by at least two of the three reported studies. Those items were used to construct a composite subscale, which appeared to offer a useful alternative to the full scale. Further analysis of the subscale's contents, however, raised questions about the dimensionality of the Marlowe-Crowne scale. Caution was urged in the use and interpretation of both the full inventory and the short form until the meaning of scale scores can be clarified.

Bias↗
PubMed1991

Recombinant human erythropoietin in the anemia of prematurity: results of a placebo-controlled pilot study.

Experimental and clinical data implicate inadequate erythropoietin production as an important reason that infants acquire this anemia and suggest that recombinant human erythropoietin (r-HuEPO) might be used to treat or prevent it. We therefore randomly assigned 20 small premature infants (birth weight less than or equal to 1250 gm) who were highly likely to require erythrocyte transfusions for anemia of prematurity to receive 6 weeks of treatment with either intravenously administered r-HuEPO (at a dose of 100 units/kg twice each week) or a placebo. Hematologic measurements, transfusion requirements, and growth were followed during therapy and for 6 months thereafter. Treated (EPO) and control babies did not differ with respect to weight, hematocrit, overall mean absolute reticulocyte count, calculated erythrocyte mass, or rate of growth. However, reticulocyte counts increased earlier in patients given r-HuEPO. Six of ten babies in the EPO group, and 8 of 10 assigned to the control group, received at least one erythrocyte transfusion during treatment. For all infants the amount of blood sampled for laboratory tests was strongly predictive of the volume of packed erythrocytes transfused (r = 0.890; p = 0.0001). Of nine infants who had less than 20 ml packed erythrocytes removed for laboratory tests, none of four given r-HuEPO received a transfusion, whereas three of five infants assigned to the placebo group received one. No toxic effects were attributable to r-HuEPO, and no significant changes in leukocyte or platelet counts occurred during treatment. Reticulocyte counts were correlated with simultaneous platelet counts and were inversely related to absolute neutrophil counts in both study groups. We conclude that r-HuEPO administration is safe and feasible at the dose studied. Additional controlled trials utilizing higher doses of r-HuEPO and larger numbers of patients are justified.

Anemia, Neonatal↗
PubMed1989

Hypoxic-reperfusion injury in the inflamed human joint.

A series of experiments showed that, on exercise of the inflamed human knee, intra-articular pressure rises above synovial capillary perfusion pressure, causing intra-articular hypoxia; and that, on cessation of exercise, there is oxidative damage to lipids and IgG within the joint. These findings are consistent with the hypothesis that persistence of synovial inflammation can be due to exercise-induced hypoxic-reperfusion injury mediated by reactive oxygen species.

Adult↗
PubMed1988

Changes in the activity of skeletal muscle calcium-activated neutral proteinase (EC 3.4.22.17) and its specific inhibitor in chickens grown at different rates in response to graded levels of dietary protein.

1. Two experiments are reported in which the effect of alteration in growth rate on the levels of avian skeletal muscle calcium-activated neutral proteinase (EC 3.4.22.17) (CANP or calpain) and its specific inhibitor (calpastatin), a system thought to be implicated in myofibrillar catabolism, was studied by means of manipulation of dietary protein concentration. 2. In Expt 1 broiler chicks were given free access to diets containing 105, 149, 197 and 212 g protein/kg for 20 d. In Expt 2 the four dietary treatments were 119, 141, 182 and 227 g protein/kg diet given for 16 d. Chick growth rate and total leg skeletal muscle weight significantly increased (P less than 0.001) with increasing dietary protein concentration in both experiments. Total skeletal muscle protein increased with the level of dietary protein, the effect being significant (P less than 0.01 and P less than 0.001 in Expts 1 and 2 respectively). 3. Minced leg muscle was homogenized in low-salt buffers, and the extract chromatographed on DEAE-cellulose to separate proteinase and inhibitor activity. The partially purified CANP enzyme and inhibitor proteins were present at a concentration broadly consistent with literature reports, and their elution characteristics and Ca2+ concentration dependence were not varied by dietary protein concentration. 4. Both the muscle CANP and CANP inhibitor activities (units/kg muscle) exhibited upward trends with growth rate and increased muscle weight. However, these differences were not statistically significant (P greater than 0.05) and were not present at all when the results were expressed as units/g muscle protein.

Animals↗
PubMed1988

Effects of dietary zeolite and vitamin A on tibial dyschondroplasia in chickens.

Four experiments were conducted to determine the effects of dietary zeolites on tibial dyschondroplasia in chicks. All studies used a practical-type corn-soybean meal diet and male broiler chicks from 1 day to 14 or 16 days of age. Vitamin A was added to the diet in the first experiment at levels of 0 or 45,000 IU/kg in addition to full or half required levels of vitamin premix, and in the second experiment at levels of 0, 11,250, 22,500 and 45,000 IU/kg in addition to full requirement levels of vitamin premix. This was done in order to determine if vitamin levels affected expression of tibial dyschondroplasia and, if so, if this expression could be influenced by 1.0% dietary zeolite. A high level of dietary vitamin A caused a lower incidence of tibial dyschondroplasia in Experiment 1 but had no effect in Experiment 2. Zeolite at graded levels of 0, .25, .50, and 1.0% in Experiment 3 and at the 1.0% level in all other experiments consistently caused a higher bone ash and a lower incidence and number of birds exhibiting severe tibial dyschondroplasia. The addition of zeolite to the diet generally had no effect on body weight or gain:feed ratio but reduced tibial dyschondroplasia scores in two of the four experiments. In Experiment 4, the addition of dietary zeolite increased 47Ca absorption but did not influence biological half-life.

Aluminum Silicates↗
PubMed1985

Does indomethacin cause extension of intracranial hemorrhages: a preliminary study.

Thirty-six infants who had an intracranial hemorrhage (diagnosed by cranial ultrasound) within four days after delivery (mean age 2.4 +/- 0.9 (SD) days), were reexamined at three- to seven-day intervals for extension of their intracranial hemorrhage. Seventeen infants had a patent ductus arteriosus and were treated with indomethacin after the initial intracranial hemorrhage was diagnosed. The age for starting indomethacin was 3.8 +/- 1.1 days. Nineteen infants did not have a patent ductus arteriosus and did not receive indomethacin. Both the indomethacin-treated and nontreated groups were similar in birth weight, gestational age, Apgar scores, gender, incidence of respiratory distress, as well as the location and the degree of hemorrhage in the initial scans. Only one of 17 (6%) infants who received indomethacin v tow of 19 (11%) infants who did not receive it, had extension of their initial intracranial hemorrhage. Although indomethacin may alter platelet function, it does not appear to cause extension of a preexisting intracranial hemorrhage.

Cerebral Hemorrhage↗
PubMed1981

Developmental follow-up of hyperventilated neonates: preliminary observations.

A group of 13 newborn infants greater than 37 weeks' gestation were selected to be hyperventilated because of severe hypoxemia refractory to conventional mechanical ventilation, ie, failure to maintain PaO2 greater than 50 torr with an FIO2 of 1.0, despite PaCO2 less than or equal to 40 torr and pH greater than or equal to 7.40. Eleven survived; nine were available for follow-up evaluations. As a group, the nine infants were exposed to a PaCO2 less than or equal to 20 torr for 51.8 +/- 11.8 (mean +/- SEM) hours, to PaCO2 less than or equal to 15 torr for 11.8 +/- 3.3 hours, to a pH greater than 7.50 for 64.4 +/- 18.6 hours, and to a pH greater than or equal to 7.60 for 6.1 +/- 2.9 hours. One infant was lost to follow-up after a normal assessment at nine months. the other eight infants (seven AGA, one markedly SGA) were at least 1 1/4 years old at the time of evaluation. The seven AGA infants had a normal developmental quotient (mean 110 [range 96-130] by Stanford-Binet or Bayley assessment); the one SGA infant had a Bayley score of 89. All eight had normal neurologic examinations. These preliminary findings are reassuring with respect to neurologic and developmental outcome following prolonged hyperventilation.

Child Development↗
PubMed1980

A histological study of the carrageenan-induced granuloma in the rat lung.

Intralobular injection of 0.17 ml of 2% carrageenan, through a ventral slit in the trachea of rats, induced localised areas of inflammation with a high survival rate. This inflammation was characterised by immediate polymorphonuclear leucocyte (PMN) infiltration into the interstitial and alveolar spaces followed in 4 days by replacement of the PMNs by carrageenan-containing macrophages. Between days 10 to 70, the macrophages rapidly increased in size and accumulated numerous large vacuoles which stained for the presence of carrageenan. Several macrophages were so large that they each filled an entire alveolar space. From days 70 to 205, the macrophage appearance was unchanged except that the staining of their carrageenan-containing vacuoles was less metachromatic with toluidine blue. Fibrosis was first noted at day 205 and consisted of several small granulomas located near large airways and blood vessels. These granulomas had a central area filled with macrophages and a peripheral zone consisting of fibroblasts, new collagen, scattered macrophages and blood vessels. The morphology of the macrophages remained essentially unchanged from days 205 to 500 but by day 500, the macrophages were found only in numerous pockets within the inflamed lobe. They still stained positive for the presence of carrageenan at day 500. The extreme longevity of these macrophages and the lack of significant fibrosis may be due to the "un-naturalness", indigestibility, and low toxicity of the irritant, carrageenan. In addition, their size and numerous vacuoles may have inhibited their movement and subsequent removal from the lung. The paucity of significant fibrosis may be due to the lack or inhibition of a "fibroblast stimulating factor" released by the macrophages or possibly the collagen was degraded as soon as it was synthesised. This carrageenan-induced inflammation is a very suitable for the study of alveolar macrophages but appears to be inappropriate for the study of pulmonary fibrosis.

Animals↗
PubMed1980

Epidemiology and aetiology of urethritis in Swaziland.

The annual incidence of urethritis can be estimated to be at lest 3750 per 100,000 population in Swaziland. In a study of 109 males with symptomatic urethritis 80% had gonorrhoea, 6% non-gonococcal urethritis (ngu) and 14% were classified as having no 'objective' urethritis (less than 5 polymorphonuclear leucocytes per highpower field in the urethral smear). The relative frequency of gonorrhoea was 80 to 95% and of non-gonococcal urethritis 5 to 20 according to which criteria are used for patient selection and/or diagnosis of ngu. Chlamydia trachomatis was cultured in 3.4% of the cases with urethritis, comprising one positive culture in 70 patients with gonorrhoea, one in 5 with ngu, and one in 12 with no 'objective' urethritis. Seventy-one percent of patients, with a comparable percentage in each diagnostic group, had chlamydial antibodies when tested by the micro immunofluorescence test to pooled chlamydial antigens. Interpretation of the chlamydial serologic results indicates that lymphogranuloma venereum is probably endemic in the country, and that oculogenital chlamydial infections are not a problem; this corresponds with the low isolation rate of Chlamydia trachomatis in the urethritis cases. The study shows that the epidemiology and causes of urethritis are clearly of a different pattern to that seen in industrialised countries. This type of study is a sound basis for a simplified but effective urethritis control programme which can be implemented in the para-urban and rural health centres in developing countries.

Chlamydia Infections↗
PubMed1976

Interaction of mouse peritoneal macrophages with fixed rabies virus in vivo and in vitro.

The resistance of mice to intraperitoneal and intramuscular infection with fixed rabies virus increases with age. Treatment of mature animals with either silica, indian ink or antimacrophage serum, which are cytotoxic for macrophages, reduced their resistance to intraperitoneal, but not to intramuscular or intracerebral infection. Transfer of peritoneal macrophages from adults to syngeneic suckling mice delayed but did not prevent mortality from intraperitoneal infection: transfer of peritoneal macrophages to intramuscular sites of infection did not protect adult mice. Rabies virus was phagocytosed by peritoneal macrophages in culture but neither replicated nor induced interferon. Evidence of active intracellular destruction of virus was obscured by thermal inactivation at 37 degrees C. Less inactivation occurred at 33 degrees C. Infected macrophages from suckling mice, but not those from adult mice, spread infection to susceptible cells.

Age Factors↗
PubMed1976

Hydrocephalus secondary to intracranial hemorrhage in premature infants.

Premature (low birth weight) infants are particularly susceptible to intracranial hemorrhage. This frequently arises from the subependymal area and may dissect into the brain or into the ventricles. If the infant survives, hydrocephalus is a frequent sequela. Because of major improvements in the care of premature infants in recent years and the proliferation of intensive care nurseries, increasing numbers of low birth weight infants are surviving and developing hydrocephalus. Seven cases are described of infants who developed hydrocephalus following intracranial bleeding. Initially, ventricular and lumbar punctures were done to attempt to control head growth but this was unsuccessful. Two were treated with temporary external ventriculostomy which did not permanently control the hydrocephalus. Definitive treatment included ventriculo-atrial shunts using an expandable 'telescopic' cardiac catheter in two and ventriculoperitoneal shunts in five. The pathogenesis and management of the condition are discussed.

Cerebral Hemorrhage↗