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Biomedical subjects

M Ballard

Publications and source records attributed to M Ballard.

16 recordsLinked to original sources
PubMed2004

Periodically varying externally imposed environmental effects on population dynamics.

Effects of externally imposed periodic changes in the environment on population dynamics are studied with the help of a simple model. The environmental changes are represented by the temporal and spatial dependence of the competition terms in a standard equation of evolution. Possible applications of the analysis are on the one hand to bacteria in Petri dishes and on the other to rodents in the context of the spread of the Hantavirus epidemic. The analysis shows that spatiotemporal structures emerge, with interesting features which depend on the interplay of separately controllable aspects of the externally imposed environmental changes.

Animals↗
PubMed1999

Disturbance of cerebral function in people exposed to drinking water contaminated with aluminium sulphate: retrospective study of the Camelford water incident.

OBJECTIVE: To establish whether people exposed to drinking water contaminated with 20 tonnes of aluminium sulphate in the Camelford area of Cornwall in the south west of England in July 1988 had suffered organic brain damage as opposed to psychological trauma only. DESIGN: Retrospective study of affected people. PARTICIPANTS: 55 affected people and 15 siblings nearest in age to one of the group but who had not been exposed to the contaminated water were studied. MAIN OUTCOME MEASURES: Various clinical and psychological tests to determine medical condition and anxiety levels in affected people. Assessment of premorbid IQ (pFSIQ) with the national adult reading test, a computerised battery of psychomotor testing, and measurement of the difference in latencies between the flash and pattern visual evoked potentials in all participants. RESULTS: The mean (SE) pFSIQ was above average at 114.4 (1.1). The most sensitive of the psychomotor tests for organic brain disease was the symbol digit coding (SDC) test (normal score 100, abnormal <85). PARTICIPANTS performed less well on this test (54.5 (6.0)) than expected from their pFSIQ (P<0.0001) and a little less poorly on the averaged less discriminating tests within the battery (86.1 (2.5), P<0.0001). In a comparison with the 15 sibling pairs (affected people's age 41.0 (3.3) years v sibling age of 42.7 (3.1) years (P=0.36) the exposed people had similar pFSIQ (114.7 (2.1)) to their siblings (116.3 (2.1), (P=0.59) but performed badly on the symbol digit coding test (51.8 (16.6)) v (87.5 (4.9) for siblings, P=0.03). The flash-pattern differences in exposed people were greater than in 42 unrelated control subjects of similar age (27.33 (1.64) ms v 18. 57 (1.47) ms, P=0.0002). The 15 unexposed siblings had significantly better flash-pattern differences than their affected siblings (13.4 (2.4) ms v 29.6 (2.9) ms, P=0.0002). No effect of anxiety could be shown on these measurements from the analysis of the anxiety scores of exposed people. CONCLUSION: People who were exposed to the contaminated water at Camelford suffered considerable damage to cerebral function, which was not related to anxiety. Follow up studies would be required to determine the longer term prognosis for affected individuals.

Adolescent↗
PubMed1999

Impact of prenatal care with reduced frequency of visits in a residency teaching program.

OBJECTIVE: To determine if decreasing the number of prenatal visits for routine obstetric patients affects pregnancy outcome. STUDY DESIGN: A historical control study was designed to include 734 deliveries from January 1 to December 31, 1991, in women who had prenatal care per American College of Obstetricians and Gynecologists Committee Opinion no. 79, January 1990, guidelines for uncomplicated obstetric care. A prospective study cohort of women with 711 deliveries from January 1 to December 31, 1994, underwent prenatal care with modified guidelines to include: first visit at 6-12 weeks to confirm dating and obtain initial laboratory data, second visit at 16-20 weeks to obtain maternal serum alpha-fetoprotein screening, third visit at 24-28 weeks for 28-week laboratory data, fourth visit at 32 weeks, fifth visit at 36 weeks, sixth visit at 38 weeks, seventh visit at 40 weeks and weekly thereafter. Pregnancy outcomes included estimated fetal weight, gestational age at delivery, preeclampsia, Apgar score at one and five minutes and delivery mode. Neonatal outcomes, including stillbirth rate, preterm delivery rate, intraventricular hemorrhage rate, bronchopulmonary dysplasia and neonatal mortality, were evaluated. RESULTS: There were no statistically significant differences in perinatal or neonatal outcomes with decreased prenatal visits from an average of 12 per pregnancy to 8. CONCLUSION: Prenatal visits can be decreased in a teaching hospital in women with uncomplicated pregnancies from the standard number, 12-14 visits, to an average of 7 or 8 per patient without adverse perinatal outcomes.

Adult↗
PubMed1994

Individual differences in preschoolers' physiological and verbal responses to videotaped angry interactions.

Individual differences in selection of intensity of angry interactions and physiological and self-reported responses to interadult anger were examined in preschoolers (N = 34). Children watched two videotaped angry interactions between adults, while their heart rates and skin conductance responses and levels were monitored; then they were interviewed. Before the second argument, children were given the perceived choice of watching an intense or mild angry exchange. Individual differences in responding to the angry interactions were found. Both (a) children with relatively higher externalizing behavior problems and (b) boys who chose to watch intense anger had lower tonic heart rates; 80% of boys with externalizing problems chose to watch intense anger. Further, children who chose to watch intense anger (a) exhibited lower declines in heart rates upon the presentation of the argument, (b) perceived the actors as more angry, and (c) reported lower amounts of distress during the argument than those who chose mild anger.

Analysis of Variance↗
PubMed1992

Intraperitoneally injected cholecystokinin-octapeptide activates pica in rats.

Cholecystokinin-octapeptide (CCK-8) was injected intraperitoneally into rats to see if it could cause them to eat kaolin (clay)--a pica behavior which has been shown to indicate gastric distress. In the first study, a single large dose of CCK-8 (20 micrograms/kg) failed to produce pica. In the second study, 4 smaller doses of CCK-8 (8 micrograms/kg), 30 min apart, produced significant ingestion of kaolin compared to the baseline condition of vehicle injections. The pica was comparable to that observed in another group of rats given a toxic dose of LiCl (127 mg/kg, IP). It is concluded that intraperitoneal injections of CCK-8 can induce a state of gastric distress in the rat.

Animals↗
PubMed1990

Response to adults' angry behavior in children of alcoholic and nonalcoholic parents.

Children from alcoholic (COAs) and nonalcoholic (NCOAs) homes (N = 35; M age = 8.02 years) were presented with videotaped segments of angry and friendly interactions matched for mode of expression of affect (verbal, indirect, nonverbal, destructive or constructive, and aggressive or affectionate) and were interviewed following each segment. Children perceived all forms of expression of anger as more negative and expressed more anger and distress in response to them. Angry adults also were perceived as having more negative feelings toward children than friendly adults. Whereas male NCOAs responded with more anger than female NCOAs, male COAs responded with less anger than female COAs. COAs more often proposed solutions to adults' interactions than NCOAs; this primarily reflected a higher rate of indirect responses intended to make others feel better. Finally, COA status and problem behaviors were associated, but analyses indicated that higher incidences of marital discord in the homes of COAs accounted for this relation.

Alcoholism↗
PubMed1986

Work therapy and return to work.

In summary, data were selected for 1 year on patients treated in the Work Tolerance Program at the Hand Rehabilitation Center in Philadelphia. The type of information obtained has been used to obtain a profile of the patient population in the Work Tolerance Program. Statistical analysis was used, not only to formulate patient demographics, but also to evaluate the length of treatment of patients in the Work Tolerance Program. This period averaged 6 weeks. The statistical analysis also revealed there was significant interaction between the type of injury and the patient's diagnosis, and the rate of return to work. The patients with injuries to bone and nerve required longer periods of treatment until they returned to work than did patients with injuries to soft tissue or combination injuries. Our statistical analysis revealed that in 1982, 75 per cent of the patients in the Work Tolerance Program returned to work to regular or modified jobs. The length of time from injury to return to work was 63 per cent longer for patients with Workers' Compensation coverage than for patients with private insurance coverage. Because the statistical analysis that 60 per cent of the patients treated in the Work Tolerance Program were Workers' Compensation insured, and 80 per cent of the patients treated in the Work Tolerance Program were secondarily referred, it should be recognized that all patients with severe hand injuries would benefit from an immediate referral to a Hand Rehabilitation Center of excellence to facilitate their therapeutic management and expedite their recovery from time of injury to return to work. This study was restricted to the analysis of length of treatment and rate of return to work. Future studies should study the effect of early referral and the application of specific treatments.

Adult↗
PubMed1985

Onchocerciasis in Sudan: the Abu Hamed focus.

The current status of onchocerciasis in Abu Hamed, Northern Province, Sudan, was studied. Of 208 persons attending out-patient clinics in villages in this region, 71 were microfilariae-positive on skin snips or had palpable nodules. Microfilariae and worms in nodules were identified as Onchocerca volvulus. No microfilariae were seen in peripheral blood. Most nodules and microfilariae were found in the pelvic region, but the intensity of infection was uniformly low (av. less than 3 mf/mg). Despite this, signs of onchocercal dermatitis were common and severe, especially over the buttocks. Papular eruptions and scarring often appeared to lead to black-grey hyperpigmentation, but no cases were seen of the unilateral, hyper-reactive 'sowda' described in Arabs in Yemen. No microfilariae were detected in the eyes of any of the patients who had positive outer canthus snips. Serum retinol concentrations were normal but mildly elevated concentrations of serum IgG, IgM and IgA were detected in many patients. Immunoglobulin E values in a sample of 20 microfilariae-positive patients were markedly higher than normal, with most in the 4,000 to 15,000 U/ml range. Eosinophil levels in differential counts of peripheral blood from the 208 villagers were markedly elevated. In skin snip surveys of over 400 villagers and school pupils, sample prevalence rates of 2 to 17.5% were recorded. Simulium biting was seasonal (November to May) and peaked in March. Over-all, the results indicate that O. volvulus infection persists in the Abu Hamed region as a serious cause of skin disease in the absence of other complicating filariases.

Adolescent↗
PubMedDate not supplied

A parental perspective on the Honeylands Home Visiting Project for severely handicapped infants provided by three mothers of older handicapped children.

Three mothers of severely handicapped children, who had not attended Honeylands nor received any home visiting, were asked to attend and participate in the monthly group meetings for the second year of the three year project (Rayner 1978). They each then decided to visit a family with their home therapist. They comment on the responsibility undertaken by all parties to this work; parents, therapist and supportive team.

Adaptation, Psychological↗