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Biomedical subjects

J Clemens

Publications and source records attributed to J Clemens.

At least 19 recordsLinked to original sources
PubMed1992

Safety and immunogenicity of single-dose live oral cholera vaccine CVD 103-HgR in 5-9-year-old Indonesian children.

Oral vaccines offer great promise as public-health measures to prevent disease in less-developed countries. CVD 103-HgR, a genetically engineered, attenuated, Vibrio cholerae O1 strain has proved effective in industrialised countries. We have assessed the safety, immunogenicity, and excretion of this live cholera vaccine in children in north Jakarta, Indonesia. 412 children aged 5-9 years received single doses of 5 x 10(6), 5 x 10(7), 5 x 10(8), 5 x 10(9), or 1 x 10(10) colony forming units (CFU) of CVD 103-HgR or placebo (5 x 10(8) inactivated Escherichia coli K-12) with buffer. All doses were well tolerated. The 5 x 10(8) CFU dose, which is highly immunogenic in subjects in industrialised countries (greater than 90% seroconversion), elicited seroconversions of vibriocidal antibody in only 16% of Indonesian children. By contrast, a single 5 x 10(9) CFU dose of vaccine resulted in high rates (75% and 87%) of seroconversion with two different batches of vaccine. A batch prepared with a centrifugation step gave significantly higher geometric mean titres (16-fold increase over baseline) than did a batch in which there was a filtration step between fermentation and lyophilisation (10-fold increase over baseline). At a 5 x 10(9) CFU dose, CVD 103-HgR is well tolerated and highly immunogenic in Indonesian children and should therefore be further investigated for use as a one-dose live oral cholera vaccine in developing countries.

Administration, Oral↗
PubMed1992

An oral B subunit: whole cell vaccine against cholera.

During the last decade there has been a rapid progress in the development of new, much improved vaccines against cholera. These vaccines, which are given orally to stimulate the gut mucosal immune system, are based on either a combination of purified cholera toxin B (binding) subunit and killed cholera vibrios of Inaba and Ogawa serotypes and El Tor and classical biotypes (B subunit-whole cell vaccine, B-WC) or on a live attenuated mutant strain of Vibrio cholerae producing the B subunit (CVD 103-HgR). The safety of the oral B-WC cholera vaccine and the immunogenicity and protective efficacy of this vaccine against both cholera and diarrhoea caused by enterotoxigenic Escherichia coli have been extensively documented, e.g. in a large randomized, placebo-controlled field trial in 90,000 persons living in a cholera endemic area. The potential for inexpensive large-scale manufacturing of the B-WC vaccine has recently been much facilitated by the introduction of recombinant DNA technology for production of the B subunit component. This now gives promise that this vaccine could become a useful, cost-effective tool in future strategies to control cholera both in endemic situations and in relation to acute epidemic outbreaks.

Administration, Oral↗
PubMed1992

Cholera vaccines.

The currently licensed parenteral cholera vaccine has not been a useful public health tool in the control of cholera. Building on the knowledge that primary infection offers significant protection against reinfection and that mucosal immunity mediates this protection, several oral cholera vaccines have been developed. These vaccine candidates or future candidates derived using the techniques of molecular biology will no doubt contribute to the control of cholera.

Cholera↗
PubMed1991

Differential diagnosis of acute viral hepatitis using rapid, fully automated immunoassays.

We report the development of three rapid, fully automated immunoassays allowing the differential diagnosis of acute viral hepatitis. These assays detect HBsAg, IgM antibody to hepatitis B core antigen (IgM anti-HBc) and IgM antibody to hepatitis A virus (IgM anti-HAV) using the IMx instrument system. All IMx assays were run in less than 45 minutes and all steps were fully automated including specimen dilution steps. Specimens from blood donors, diagnostic and hospital patients, and individuals with a variety of infectious and immune diseases were tested for IgM anti-HAV (n = 1473) or for IgM anti-HBc (n = 1606) or for HBsAg (n = 9700) by the IMx and commercially available EIA and RIA. Each IMx assay showed 99.8% agreement with current EIA. Reproducibility in all hepatitis IMx assays was significantly better than that observed with manual or semiautomated assays; within-run and between-run % CV ranged from 2.2 to 4.8 and 3.5 to 10.3 respectively. In 29 acute hepatitis B patients studied, HBsAg and IgM anti-HBc were detected in the first available patient bleed collected from 0 to 4 week from the onset of symptoms. IgM anti-HBc persisted at reactive levels in the IMx assay for 1 to 24 weeks (mean 12.1 +/- 5.3 weeks) after the patient presented with symptoms. In individuals exposed to hepatitis A, IgM anti-HAV was detectable by IMx by 40 days post exposure (average 33.5 days) and IgM had declined to unreactive levels in IMx for all patients by from 3 to 6 months post exposure. These data demonstrate the use of these rapid IMx assays for differentiation of acute hepatitis A and B.

Acute Disease↗
PubMed1991

Evidence for recent diarrhoeal morbidity as a risk factor for persistent diarrhoea: a case-control study.

The association between persistent diarrhoea and 'recent morbidity' defined as that occurring within the two-month period immediately preceding the onset of persistent diarrhoea was investigated in a population-based case-control study in rural North India. In two separate matched case-control analyses children with persistent diarrhoea (cases) were compared to population controls (five controls matched to each case) and acute diarrhoeal controls (three controls matched to each case). After correcting for possible confounding variables, comparing children with persistent diarrhoea and matched population controls, presence of a recent diarrhoeal illness was significantly associated with persistent diarrhoea with an odds ratio (OR) 2.6 (95%) confidence interval (CI): 1.1-7.1; p less than 0.05); during infancy this OR was 5.2 (95% CI: 1.0-31.9; p less than 0.01). Comparing children with persistent diarrhoea to matched acute diarrhoeal controls, presence of recent diarrhoeal illness was associated with an OR of 5.1 (95% CI: 1.3-20.3) in favour of the episode becoming persistent; in infants this OR was 10.4 (95% CI: 1.1-132.4; p less than 0.001).

Acute Disease↗
PubMed1991

The clinical and immunologic response of Chilean infants to Haemophilus influenzae type b polysaccharide-tetanus protein conjugate vaccine coadministered in the same syringe with diphtheria-tetanus toxoids-pertussis vaccine at two, four and six months of age.

The safety and immunogenicity of a vaccine against Haemophilus influenzae type b consisting of purified polyribosylribitolphosphate conjugated to tetanus toxoid (PRP-T) was evaluated in 278 Chilean infants who were randomly assigned to one of three treatment groups: Group A, PRP-T mixed with diphtheria-tetanus toxoids-pertussis (DTP) vaccine in a single syringe and given as a single inoculation in one arm and placebo in the other arm; Group B, PRP-T given in one arm and DTP in the other arm; Group C, DTP given in one arm and placebo in the other. Infants were immunized at 2, 4 and 6 months of age and examined daily for 4 days after each immunization; serum PRP antibodies were measured at baseline and 2 months after each dose. The only adverse systemic reaction attributable to PRP-T beyond that caused by DTP alone was a 7 to 20% increase in febrile responses in the first 24 hours after the first and second doses of vaccine; the fevers were largely low grade and not accompanied by increased irritability, diminished activity or loss of appetite, compared with the group who received DTP without PRP-T. After the first dose 72% of infants who received PRP-T combined with DTP and 67% who received it in a separate arm attained antibody concentrations greater than or equal to 0.15 micrograms/ml. After two doses of PRP-T, 93 and 95%, respectively, had concentrations greater than or equal to 0.15 microgram/ml and after three doses 100% of infants who received PRP-T had such titers.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Bacterial↗
PubMed1991

Rotavirus-associated diarrhea in rural Bangladesh: two-year study of incidence and serotype distribution.

Stools were evaluated from 5,811 patient visits for treatment of diarrhea in Matlab, Bangladesh, between June 1987 and May 1989. The stools were analyzed to determine the distribution of serotypes of group A rotaviruses (RV). A total of 898 stool samples (15.5%) contained RV, as determined by using an enzyme-linked immunosorbent assay. RV isolates from 855 of these samples were serotyped by using serotype-specific synthetic oligonucleotide probes. A total of 558 (65.3%) could be assigned to specific serotypes: 166 (19.4%), 228 (26.7%), 39 (4.6%), and 125 (14.6%) belonged to serotypes 1 through 4, respectively; 12 (1.4%) hybridized with more than one serotype; and 285 (33.3%) failed to hybridize. RV diarrhea was evident throughout the year, with peaks in the dry winter months and in September 1988, coinciding with a major flood. RV was isolated from 46.6% of patients between 7 and 12 months old. Among children under 24 months of age with RV diarrhea, 1.2% (10 of 828) died. The corresponding percentage for children with diarrhea from all causes is 0.9% (29 of 3,301).

Bangladesh↗
PubMed1990

A population-based retrospective assessment of the disease burden resulting from invasive Haemophilus influenzae in infants and young children in Santiago, Chile.

Clinical discharge and laboratory records were reviewed in the seven government hospitals that provide care for 93% of the pediatric population of Santiago, Chile, to detect cases of meningitis and other invasive (bacteremia-associated) infections caused by Haemophilus influenzae. infections that occurred in children less than five years of age from January, 1985, through December, 1987, were recorded and matched with census data to calculate incidence rates. The incidence of meningitis and non-meningitis syndromes peaked in the 6- to 11-month age group and tapered sharply after 12 months of age. The city-wide incidence (ca. 21.6 cases/10(5) children less than 5 years of age) is one-third to one-half that reported for the general pediatric population in the United States. However, there is much evidence for under-reporting in Santiago. In Area Norte, served by Roberto del Rio Children's Hospital where H. influenzae has been a subject of research by pediatricians for years, the incidence of invasive H. influenzae infections (42.5/105) is approximately two-fold higher than the rest of Santiago. The cumulative proportions of episodes of H. influenzae disease occurring in successively older age groups closely parallel the pattern seen in the general United States pediatric population. Although only ca. 20% of all episodes occur during the first 6 months of life, nearly 80% of episodes are seen by 18 months of age. Based on the observed incidence rates, the apparent underreporting and the high city-wide case fatality of Hib meningitis (16%), invasive H. influenzae infections represent an important public health problem in Santiago, Chile.

Age Factors↗
PubMed1989

New cholera vaccines.

Development of improved cholera vaccines has progressed rapidly in recent years. An oral killed vaccine, designed to evoke antibacterial as well as antitoxic intestinal immunity, has proved to be completely safe and to protect against cholera for at least 3 years. This vaccine also confers substantial though more short-lasting immunity against diarrhoea caused by enterotoxigenic Escherichia coli. Significant progress has also been made towards developing a live attenuated cholera vaccine using recombinant DNA techniques. The advent of effective oral cholera vaccines gives hope for improved control of cholera in the Third World.

Administration, Oral↗
PubMed1989

User fees for health care in developing countries: a case study of Bangladesh.

In designing country health care programs to achieve the goals of the Alma Alta declaration of 'Health for All', developing countries have been confronted with the problem of increased health care needs and decreased available resources. Health economists have proferred several possible solutions to this fiscal shortfall, including cost-recovery measures through the imposition of user fees for curative services at government health facilities. Health care providers have been noticeably absent from discussions of the many possible implications of these fees; consequently, resultant programs and policies may be economically sound but may fail to place a sufficient emphasis on features designed to maintain and improve the health of the population. In the present paper we examine the possible impact of user fees on the health of individuals residing in Bangladesh, one potential candidate country for user fees. We note evidence that the existing government health care system appears already to be providing care to two of the most medically vulnerable groups in Bangladesh, the poor and women, and provide evidence that such fees may seriously interfere with maintaining this patient profile. We discuss the significant public health role that curative care provides for the individuals, their families and the wider community. We suggest that additional questions should be asked by health care providers, anthropologists and economists prior to institution of user fees in the government system and that such measures should first be introduced in an experimental format with a rigorous and comprehensive impact evaluation.

Bangladesh↗
PubMed1989

Periampullary neoplasms in von Recklinghausen's disease.

A case of neurofibromatosis is reported in a patient who was initially seen with obstructive jaundice caused by a carcinoid tumor originating from the ampulla of Vater. An extensive review of the literature suggests that patients with von Recklinghausen's disease are at significant risk for periampullary neoplasms of neural-crest and non-neural-crest origin. The tendency of those tumors to arise from the ampulla of Vater has diagnostic and therapeutic implications.

Adult↗
PubMed1989

General pharmacology of nizatidine in animals.

Nizatidine (N-[2-[[[2-[(dimethylamino)methyl-4-thiazolyl]- methyl]thio]ethyl]-N'-methyl-2-nitro-1,1-ethenediamine, LY139037, Axid) is a novel, potent, and selective H2-antagonist. The potential secondary pharmacologic effects of this agent on the cardiovascular, respiratory, gastrointestinal, renal, hepatic, autonomic, and central nervous systems as well as effects on circulating blood glucose and the acute inflammatory response were examined. Nizatidine was generally inactive in the tests conducted in mice, rats, guinea pigs, rabbits, and dogs. Nizatidine and the reference H2-antagonist, cimetidine, both produced effects upon the cardiovascular and respiratory systems by intravenous administration in anesthetized dogs at doses in excess of the intended clinical exposure. In summary, these studies confirm the selective pharmacologic activity of nizatidine and indicate a low potential for secondary pharmacologic side effects to be encountered clinically.

Animals↗
PubMed1989

Descriptive epidemiology of persistent diarrhoea among young children in rural northern India.

In order to determine the descriptive epidemiology of persistent diarrhoea in rural northern India, a cohort of 963 children aged 0-71 months was followed prospectively for 12 months through weekly household visits. The incidence of persistent diarrhoea was 6.3 per 100 child-years among those aged 0-71 months, and was highest (31 per 100 child-years) among those aged 0-11 months. There were no significant sex-related differences in the incidence of the disease, and the overall seasonal distribution of acute and persistent diarrhoea was similar. The persistence of diarrhoeal symptoms was significantly correlated with a higher initial mean stool frequency (P less than 0.01) and passage of gross blood with stools (P less than 0.001). Persistent diarrhoea was an important problem among children during the first 2 years of life. Established enteric pathogens were isolated during the initial illness in 46.4% of persistent and 55.4% of acute episodes. Pathogens isolated during persistent episodes included enterotoxigenic Escherichia coli (ETEC 9.3%), Salmonella spp. (4.7%), as well as campylobacter (4.7%), Shigella spp. (2.3%), Entamoeba histolytica (2.3%), and rotavirus (2.3%). Similar proportions of these pathogens were isolated also during episodes of acute diarrhoea. Multiple pathogens were isolated in 7% of the persistent and 5% of the acute episodes. E. coli that manifested aggregative adherence (EAEC-A) was more common (34.9% versus 12.3%) in persistent than acute episodes (P less than 0.01), and initial faecal excretion of EAEC-A was significantly associated with the persistence of a diarrhoeal episode.

Child↗
PubMed1988

The insulin-like growth factor-II (IGF-II) receptor of rat brain: regional distribution visualized by autoradiography.

The presence of insulin-like growth factor-II (IGF-II) in brain and cerebral spinal fluid prompted us to investigate the distribution of receptors for this peptide in rat brain slices. Human 125I-IGF-II (10 pM) was incubated for 16 h at 4 degrees C with thaw-mounted slices of rat brain from 11 different brain regions. Incubations in the absence or presence of excess unlabeled human IGF-II or insulin were performed and the labeled tissues were exposed to X-ray film for 4-7 days. Autoradiographs showed dense labeling in the granule layers of the olfactory bulbs, deep layers of the cerebral cortex, pineal gland, anterior pituitary, hippocampus (CA1-CA4, and dentate gyrus), and the granule cell layers of the cerebellum. Unlabeled IGF-II eliminated most of the binding in these brain regions while insulin produced only a minimal reduction in the amount of 125I-IGF-II bound. These results indicate that a neural receptor for IGF-II is uniquely distributed in rat brain tissue supporting the notion that this peptide might play an important role in neuronal functioning.

Animals↗