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Biomedical subjects

P R Fischer

Publications and source records attributed to P R Fischer.

At least 19 recordsLinked to original sources
PubMed2005

Causes of lead toxicity in a Nigerian city.

BACKGROUND: Up to 70% of young Nigerian children have been reported to have blood lead concentrations > or =10 microg/dl. AIMS: To better elucidate risk factors for lead toxicity among Nigerian families with children at risk for lead toxicity. METHODS: Two geographic wards in Jos, Nigeria were selected for study, one previously reported to have a high mean blood lead level (37 (SD 13) microg/dl) and one with a lower mean blood lead level (17 (SD 10) microg/dl) in young children. Data pertaining to potential risk factors for lead exposure were collected from children and adults in 34 households. RESULTS: The mean (SD) blood lead concentration of 275 subjects, aged 3 weeks to 90 years, was 8.7 (5.7) microg/dl (range 1-34 microg/dl); 92 (34%) had concentrations > or =10 microg/dl. In multivariate analysis, an age of 5 years and under, flaking house paint, residence near a gasoline seller, male gender, increasing maternal and paternal education, and use of a lead ore eye cosmetic were independently associated with greater blood lead concentration. Vehicle ownership was associated with reduced lead concentration. Compared with the low-lead ward, residence in the high-lead ward remained significantly associated with greater lead values, indicating that additional factors likely contribute to lead exposure. CONCLUSION: Although the cause of increased lead levels in Jos appears to be multi-factorial, several remediable sources contribute to lead exposure in Nigeria.

Adolescent↗
PubMed2004

The sick placenta-the role of malaria.

The human placenta is an ideal site for the accumulation of Plasmodium falciparum malaria parasites, and as a consequence serious health problems arise for the mother and her baby. The pathogenesis of placental malaria is only partially understood, but it is clear that it leads to a distinct epidemiological pattern of malaria during pregnancy. The objectives of this review are: (1) To review recent data on the epidemiology of malaria in pregnancy, with emphasis on placental malaria; (2) to describe the pathological changes and immunological factors related to placental malaria; and (3) to discuss briefly the functional consequences of this infection for the mother and her baby. The review attempts to bring together local events at the maternal-fetal interface which encompass immunological and pathological processes which relate to the epidemiological pattern of malaria in pregnancy in areas of both high and low malaria transmission. An integrated understanding of the epidemiological, immunological and pathological processes must be achieved in order to understand how to control malaria in pregnancy. The yearly exposure of at least 50 million pregnancies to malaria infection makes it the commonest and most recurrent parasitic infection directly affecting the placenta. These statistics and our limited understanding of its pathogenesis suggest the research priorities on this subject.

Cytokines↗
PubMed2000

Case-control study of factors associated with nutritional rickets in Nigerian children.

OBJECTIVE: Because the causes of nutritional rickets in tropical countries are poorly understood, we conducted a case-control study to determine factors associated with rickets in Nigerian children. STUDY DESIGN: We compared 123 Nigerian children who had rickets with matched control subjects. Dietary, demographic, anthropometric, and biochemical data were collected to assess factors related to calcium and vitamin D status, which might predispose children to rickets. RESULTS: Mean (+/- SD) daily dietary calcium intake was low in both children with rickets and control children (217 +/- 88 mg and 214 +/- 77 mg, respectively; P =.64). Children with rickets had a greater proportion of first-degree relatives with a history of rickets (14.6% vs 3.1%; P <.001), a shorter mean duration of breast-feeding (16.0 vs 17.3 months; P =.041), and a delayed age of walking (14 vs 12 months; P <.001). Among children with rickets, biochemical features suggestive of calcium deficiency included hypocalcemia, extremely low calcium excretion, and elevated 1, 25-dihydroxyvitamin D and parathyroid hormone values. Median 25-hydroxyvitamin D concentrations were 32 and 50 nmol/L (13 and 20 ng/mL) in children with rickets and control children, respectively (P <.0001). Only 46 subjects with rickets (37%) had 25-hydroxyvitamin D values <30 nmol/L (12 ng/mL). CONCLUSIONS: Vitamin D deficiency appears unlikely to be the primary etiologic factor of rickets in African children. Moreover, low dietary calcium intake alone does not account for rickets. Insufficient dietary calcium probably interacts with genetic, hormonal, and other nutritional factors to cause rickets in susceptible children.

Adolescent↗
PubMed2000

Radiographic scoring method for the assessment of the severity of nutritional rickets.

Radiographic changes of rickets are well characterized, but no method of grading the severity of these changes has been in general use. Consequently, it is difficult to compare objectively or follow radiographic improvement. We prospectively evaluated the utility and reproducibility of a scoring method for measuring the severity of rickets. A 10-point score for radiographs of wrists and knees was devised to assess the degree of metaphyseal fraying and cupping and the proportion of the growth plate affected. The score progresses in half point increments from zero (normal) to 10 points (severe). Four trained physicians independently scored radiographs on two separate occasions from 67 children with active rickets. A broad representation of mean radiographic scores was moderately correlated with alkaline phosphatase (r = 0.58). Interobserver correlation of radiographic scores was 0.84 or greater for all observer pairs and intraobserver correlation was 0.89 or greater for each observer. Researchers and clinicians should find the score useful to assess objectively the severity of rickets.

Alkaline Phosphatase↗
PubMed2000

Vitamin D receptor polymorphisms and nutritional rickets in Nigerian children.

Nutritional rickets is common in Nigeria where vitamin D deficiency is rare and dietary insufficiency of calcium is common. It occurs more commonly in siblings of affected children than of unaffected children. Postulating that vitamin D receptor (VDR) polymorphisms might relate to the susceptibility of some Nigerian children to develop rickets in the setting of low calcium intake, we compared the VDR genotypes, as determined by the presence or absence of Bsm I, Apa I, Taq I, and Fok I restriction enzyme cleavage sites, between 105 children with active nutritional rickets and 94 subjects representative of the community from which the rachitic children came. In the rickets group, the ff genotype was less common than in the community group, and the FF genotype was relatively increased (f allele frequency, 17% in rachitic children and 26% in the community group, p = 0.03). Neither individual allele frequencies for the other polymorphisms nor combinations of genotypes at different sites were different between the rachitic and community groups. Although it is not clear why a presumed better-functioning VDR variant (F allele) is associated with an increased risk of developing rickets, this study raises the possibility that VDR alleles might be important in determining an individual's susceptibility to developing rickets when faced with dietary calcium deficiency.

Adult↗
PubMed1999

A comparison of calcium, vitamin D, or both for nutritional rickets in Nigerian children.

BACKGROUND: Nutritional rickets remains prevalent in many tropical countries despite the fact that such countries have ample sunlight. Some postulate that a deficiency of dietary calcium, rather than vitamin D, is often responsible for rickets after infancy. METHODS: We enrolled 123 Nigerian children (median age, 46 months) with rickets in a randomized, double-blind, controlled trial of 24 weeks of treatment with vitamin D (600,000 U intramuscularly at enrollment and at 12 weeks), calcium (1000 mg daily), or a combination of vitamin D and calcium. We compared the calcium intake of the children at enrollment with that of control children without rickets who were matched for sex, age, and weight. We measured serum calcium and alkaline phosphatase and used a 10-point radiographic score to assess the response to treatment at 24 weeks. RESULTS: The daily dietary calcium intake was low in the children with rickets and the control children (median, 203 mg and 196 mg, respectively; P=0.64). Treatment produced a smaller increase in the mean (+/-SD) serum calcium concentration in the vitamin D group (from 7.8+/-0.8 mg per deciliter [2.0+/-0.2 mmol per liter] at base line to 8.3+/-0.7 mg per deciliter [2.1+/-0.2 mmol per liter] at 24 weeks) than in the calcium group (from 7.5+/-0.8 [1.9+/-0.2 mmol per liter] to 9.0+/-0.6 mg per deciliter [2.2+/-0.2 mmol per liter], P<0.001) or the combination-therapy group (from 7.7+/-1.0 [1.9+/-0.25 mmol per liter] to 9.1+/-0.6 mg per deciliter [2.3+/-0.2 mmol per liter], P<0.001). A greater proportion of children in the calcium and combination-therapy groups than in the vitamin D group reached the combined end point of a serum alkaline phosphatase concentration of 350 U per liter or less and radiographic evidence of nearly complete healing of rickets (61 percent, 58 percent, and 19 percent, respectively; P<0.001). CONCLUSIONS: Nigerian children with rickets have a low intake of calcium and have a better response to treatment with calcium alone or in combination with vitamin D than to treatment with vitamin D alone.

Alkaline Phosphatase↗
PubMed1999

Pseudoephedrine and air travel-associated ear pain in children.

BACKGROUND: Young children often appear bothered by ear pain during ascent and descent while traveling on commercial airplanes. While pseudoephedrine hydrochloride is effective in decreasing the risk for earache in adults with recurrent air travel-associated ear pain, such use in children has not been studied. OBJECTIVE: To assess the efficacy and side effects of prophylactic pseudoephedrine in children traveling by air. DESIGN: A placebo-controlled, double-blind clinical trial. SUBJECTS AND METHODS: Children aged 6 months to 6 years were included in this study. Pseudoephedrine hydrochloride (1 mg/kg body weight) or placebo was administered 30 to 60 minutes prior to departure on commercial air flights. Caregivers noted historical details and the degree of apparent ear pain, drowsiness, and excitability with ascent and descent. RESULTS: Ninety-one flights involving 50 children were studied, with ear pain being reported in 13 (14%) of flights. Ear pain was not associated with a history of air travel-associated ear pain, recent ear infection, or recent upper airway symptoms. Pseudoephedrine use was not associated with a decrease in ear pain during either ascent (4% with pseudoephedrine vs 5% with placebo; P approximately 1.00) or descent (12% with pseudoephedrine vs. 13% with placebo; P approximately 1.00). Pseudoephedrine use was, however, linked to drowsiness at takeoff (60% with pseudoephedrine vs. 27% with placebo; P = .003) but not at landing (P = .39). Treatment was not associated with excitability at takeoff (P = .09) or landing (P approximately 1.00). CONCLUSIONS: Ear pain is not uncommon in children traveling by commercial aircraft. The predeparture use of pseudoephedrine does not decrease the risk for in-flight ear pain in children but is associated with drowsiness.

Aircraft↗
PubMed1999

Nutritional rickets without vitamin D deficiency in Bangladesh.

To understand nutritional rickets in Bangladesh better, 14 rachitic and 13 'unaffected' children were evaluated. Seventy per cent of children with active rickets had no evidence of either vitamin D deficiency or familial rickets. Rickets in Bangladesh is probably related to calcium deficiency. Abnormalities in 'unaffected' children suggest that subclinical calcium insufficiency is common.

Bangladesh↗
PubMed1998

Absence of vitamin D deficiency in young Nigerian children.

OBJECTIVE: To determine the prevalence of vitamin D deficiency in young Nigerian children residing in an area where nutritional rickets is common. STUDY DESIGN: A randomized cluster sample of children aged 6 to 35 months in Jos, Nigeria. RESULTS: Of 218 children evaluated, no child in the study had a 25-hydroxyvitamin D (25-OHD) concentration <10 ng/mL (the generally held definition of vitamin D deficiency). Children spent an average of 8.3 hours per day outside of the home. Twenty children (9.2%) had clinical findings of rickets. Children with clinical signs of rickets were more likely to be not currently breast fed and have significantly lower serum calcium concentrations than those without signs of rickets (9.1 vs 9.4 mg/dL, respectively, P =.01). Yet, 25-OHD levels were not significantly different between those children with clinical signs of rickets and those without such clinical signs. CONCLUSION: Vitamin D deficiency was not found in this population of young children in whom clinical rickets is common. This is consistent with the hypothesis that dietary calcium insufficiency, without preexisting vitamin D deficiency, accounts for the development of clinical rickets in Nigerian children.

Breast Feeding↗
PubMed1998

Travel with infants and children.

The risks faced by children traveling internationally may be minimized by providing and applying advice about comfort, safety, skin protection, and food and water hygiene. Prior to travel, children should be current on standard immunizations and may receive several specialized vaccines. Antibiotics for the presumptive treatment of travelers' diarrhea are usually indicated, and malaria chemoprophylaxis may be safely administered even to young children. Evaluation and care following prolonged stays in foreign countries can decrease the burden of imported disease.

Bacterial Vaccines↗
PubMed1998

Short report: severe malaria associated with blood group.

The ABO blood groups are not linked to the incidence of simple malaria infection but have been associated with rosette formation. In an effort to see if clinically severe malaria is associated with blood group, 489 patients were studied in Zimbabwe. Patients with malaria and group A blood had lower hemoglobin levels and more risk of coma than did infected patients with other blood groups. In this population, severe malaria is associated with blood group.

ABO Blood-Group System↗
PubMed1997

Congenital malaria: an African survey.

Even in malaria-endemic areas, congenital malaria has been considered to be rare. Some recent reports suggest, however, that up to one fourth of newborns in some areas may be parasitemic. In an effort to determine current prevalence rates of congenital malaria, malaria smears were done on peripheral blood from 100 peripartum mothers and on cord blood from their offspring at each of seven sites spanning sub-Saharan Africa. The prevalence rate of maternal parasitemia was 15% overall and varied from 4% to 30% at the different sites. Congenital malarial infection was found in 7% of newborns, the prevalence rate varying from 0% to 23% at the different sites. There was no apparent relationship between the season of sampling and either the prevalence rates of parasitemia or the penetrance of malaria from mother to offspring. In summary, congenital malarial infection is not rare in sub-Saharan Africa, but the prevalence rate of neonatal parasitemia varies from site to site.

Africa↗
PubMed1997

HIV seroprevalence amongst pregnant women in northeastern Zaire.

To assess the seroprevalence of HIV in pregnant women in northeastern Zaire and factors that correlate with seropositivity, sequential blood sampling and interviews were performed on 700 women at antenatal clinics in northeastern Zaire. The seroprevalence of the 3 clinics surveyed varied from 0.3%-5.5%, rates being higher in more urban areas. Seropositivity was associated with greater education (P<0.001) and having a partner whose job involved travelling (P<0.001). No correlation was found with marital status, age, or gravidity. Women in northeastern Zaire are at a greater risk of being infected with HIV if they are well educated or have a husband who travels due to his work. Health education on HIV should be particularly directed at women who are well educated and at men who have 'mobile' jobs.

Democratic Republic of the Congo↗
PubMed1996

Nosocomial mumps: report of an outbreak and its control.

BACKGROUND: Mumps is a relatively uncommon disease in the United States, and nosocomial transmission of mumps is rare. METHODS: When a recently arrived Mexican immigrant became ill with mumps in a pediatric hospital in the United States, control measures and careful secondary case surveillance were instituted. Outbreak control included isolation of the patient with symptoms, seclusion of patients potentially incubating mumps virus, and immunization of susceptible patients and health care workers. RESULTS: A 3-year-old patient showed symptoms of mumps 18 days after onset of illness in the index patient. Two employees, a physical therapist and a nurse, became ill with mumps 20 and 28 days after the onset of illness in the index patient. No other hospital or community cases of mumps were identified. CONCLUSIONS: Outbreak control measures were incompletely successful in stopping the spread of mumps. Preadmission immunization of all patients and mumps-specific screening and vaccination of hospital employees might be indicated in such a situation, but such measures are neither easy nor inexpensive.

Adult↗
PubMed1996

Wistar rat-Plasmodium berghei model does not approximate human congenital malaria.

Until recently, congenital malaria was thought to be rare. Now, several reports suggest that more than 10% of newborns in some settings are parasitemic. The pathophysiology of transplacental transmission of Plasmodium is not well understood, and no animal model of congenital malaria exists. A rodent model of malaria in pregnant females, however, has been developed. In an effort to test the usefulness of this model in the study of congenital malaria, Wistar rats were injected intraperitoneally with approximately 10(6) NYU-2 strain Plasmodium berghei-infected erythrocytes at various times relative to conception. Perinatal maternal and neonatal blood was tested for the presence of parasites. Two rats infected preconceptually, 1 at 29 and the other at 11 days prior to mating, delivered aparasitemic pups. Fourteen rats were inoculated during gestation. Five of 5 rats infected on the fifth gestational day succumbed prior to delivery; 1 fetus was parasitemic. Offspring of females infected on the 9th, 10th, 12th, and 14th days of gestation were aparasitemic at birth. Four rats conceived after an initial Plasmodium infection had waned and were reinfected during pregnancy; none of their pups showed evidence of parasitemia. Thus, though rare, transplacental passage of malaria parasites can occur in rats. The Wistar rat-P. berghei model of gestational malaria, however, does not seem to be useful for the study of congenital malaria.

Animals↗