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At least 19 recordsLinked to original sources
PubMed1989

Hb Chad or alpha 223(B4)Glu----Lys beta 2 observed in members of a Surinam family in association with alpha-thalassemia-2 and with Hb S.

Three different hemoglobinopathies, i.e. Hb S, Hb Chad [alpha 23 (B4)Glu----Lys], and alpha-thalassemia-2 (-3.7) have been observed in eight members of a family from Surinam. The proposita had all three abnormalities, while her mother and four of her half-brothers had Hb Chad together with an alpha-thalassemia-2 heterozygosity or homozygosity. Gene mapping and dot-blot analysis of amplified DNA identified a G----A mutation in codon 23 of the alpha 2 alpha 1 hybrid gene resulting in the Glu----Lys substitution. The quantity of the alpha-Chad chain averaged 31.5% in its carriers with an additional alpha-thalassemia-2 heterozygosity [-alpha Chad(-3.7 kb)/alpha alpha], and 43% in the two carriers with an additional alpha-thalassemia-2 homozygosity [-alpha Chad (-3.7 kb)/-alpha (3.7 kb)]. These quantities are considerably higher than those reported for families from Chad, China, and Japan; the low levels of 14.5-24% Hb Chad in members of previously reported cases suggest a mutation on a chromosome with two alpha-globin genes [alpha alpha Chad/alpha alpha or alpha Chad alpha/alpha alpha].

Adult↗
PubMed1990

Changes in the pancreatic A-, B- and D-cell populations during development of diabetes in spontaneously diabetic Chinese hamsters of the Asahikawa colony (CHAD).

We investigated the pathological changes in pancreatic islets during the development of diabetes in spontaneously diabetic Chinese hamsters of the Asahikawa colony (CHAD), using morphometric analysis and specific immunocytochemical methods. We also investigated the relationships between changes in islet cell composition and the hormonal changes in the plasma and pancreas. Plasma and pancreatic insulin levels were significantly lower in diabetic hamsters than in pre-diabetic hamsters. However, plasma insulin levels in the pre-diabetic hamsters were significantly higher than those in the hamsters from the non-diabetic control strain, although the pancreatic insulin content in the pre-diabetics was significantly lower than that in the non-diabetics. Since even a severely diabetic CHAD is alive for many months after the onset of the disease without injections of insulin, its clinical course seems to be close to that of type 2 human diabetes. In contrast, plasma and pancreatic glucagon levels were significantly higher in diabetic hamsters than in non-diabetics and pre-diabetics. There were significantly positive correlations between plasma and pancreatic insulin, and plasma and pancreatic glucagon levels in CHAD (P less than 0.01). On the other hand, no significant differences in the pancreatic somatostatin content were found among the non-diabetics, pre-diabetics, and severe diabetics. Significant correlations were found between plasma and pancreatic hormone levels (except for somatostatin) and the advance of diabetes in CHAD (P less than 0.01). Morphometric analysis by planimeter revealed that islets in the severe diabetics were 25% smaller than in the pre-diabetics. Significantly less B-cell area within the diabetic islets was found when compared with the non-diabetic and pre-diabetic islets. Significantly larger A- and D-cell areas within the diabetic islets were found compared with the non-diabetic and pre-diabetic islets. There was a significant correlation between the areas of the three types of cell within the islets and the severity of diabetes (P less than 0.01). It is suggested, therefore, that the pancreatic islet function in CHAD is closely associated with the morphologic changes in islet endocrine cells. The elevation of plasma and pancreatic glucagon levels and the marked increase of the A-cell area within the islets from severely diabetic CHAD may reveal an absolute increase of A-cell numbers.

Animals↗
PubMed1984

Cisplatin-MECY (methotrexate-leucovorin rescue plus cyclophosphamide) versus cisplatin-CHAD (cyclophosphamide, hexamethylmelamine, doxorubicin, and cisplatin) as initial chemotherapy in stage III-IV ovarian adenocarcinoma.

Thirty-three patients with advanced-stage ovarian adenocarcinomas, with no prior chemotherapy, were treated with weekly cisplatin (DDP) for four courses followed by five monthly courses of one of two randomly assigned multidrug combinations. These combinations were high-dose methotrexate-leucovorin plus cyclophosphamide (MECY) or cyclophosphamide, hexamethylmelamine, doxorubicin, and DDP (CHAD). Patients with no clinically measurable disease after 6 months of therapy were evaluated by laparoscopy. In the absence of disease progression at the time of the laparoscopy the study design called for a repeat cycle of four weekly DDP courses and another five monthly courses of the assigned multidrug combination. All patients with no evidence of disease after 1 year of treatment had a second-look laparoscopy which, if negative, was followed by a second-look laparotomy. This report includes all of the consecutively entered patients observed for a minimum of 1 year or to death. DDP-MECY and DDP-CHAD were similarly active for overall response rates and complete response rates according to laparoscopic criteria. However, DDP-MECY had a statistically significantly lower relapse rate (P less than 0.02) and a statistically significantly higher negative second-look laparotomy rate than did DDP-CHAD. Using all entered patients, with no exclusions from analysis, eight of 17 patients (47%) treated with DDP-MECY had negative second-looks after 1 year of treatment. This compares with one of 16 (6%) negative second-looks in patients treated with DDP-CHAD (P less than 0.02). The high negative second-look rate with DDP-MECY is exciting. Positive cytologic washings at the 6-month laparoscopic evaluation were highly predictive that residual disease would be found at the 1-year second-look surgery. Only one patient with positive peritoneal cytology after 6 months of treatment was found to have a negative second-look after 1 year of therapy.

Adenocarcinoma↗
PubMed1995

The first australopithecine 2,500 kilometres west of the Rift Valley (Chad)

The first sites with Pliocene and Pleistocene mammals west of the Rift Valley in Central Africa in northern Chad were reported in 1959 (ref. 1), and documented the presence of mixed savannah and woodland habitats. Further sites and a probable Homo erectus cranio-facial fragment were subsequently discovered. In 1993 a survey of Pliocene and Pleistocene formations in the Borkou-Ennedi-Tibesti Province of Chad (B.E.T.) led to the discovery of 17 new sites in the region of Bahr el Ghazal (classical Arabic for River of the Gazelles) near Koro Toro. One site, KT 12 (15 degrees 58'10"N, 18 degrees 52'46"E) yielded an australopithecine mandible associated with a fauna biochronologically estimated to be 3.0-3.5 Myr old. Australopithecine species described since 1925 are known from southern Africa and from sites spread along the eastern Rift Valley from Tanzania to Ethiopia (Fig. 1). This new find from Chad, which is most similar in morphology to Australopithecus afarensis, documents the presence of an early hominid a considerable distance, 2,500 km, west of the Rift Valley.

Adult↗
PubMed1979

The CHAD and HAD regimens in advanced ovarian cancer: combination chemotherapy including cyclophosphamide, hexamethylmelamine, adriamycin, and cis-dichlorodiammineplatinum(II).

Combination chemotherapy consisting of hexamethylmelamine, adriamycin, and cis-dichlorodiammineplatinum(II) was given to 27 patients with advanced epithelial ovarian cancer whose disease had progressed while receiving therapy including alkylating agents. Eighteen patients (67%) had objective partial or complete remissions for a projected median duration of 7 months. Based on this high level of activity in this poor-risk group, the three drugs were combined with cyclophosphamide in a four-drug regimen (CHAD) for initial therapy suitable for outpatient administration. Nineteen of 21 evaluable patients (90.4%) receiving CHAD responded. Complete clinical remissions were noted in ten patients (47.6%) and were confirmed at "second-look" laparotomy in two of these. An additional five patients without evaluable disease after initial surgery are free from relapse at 4--15 months. Toxicity was only moderately severe; 28% of the patients had wbc counts less than 2000/microliters at some point. Nephrotoxicity from cis-dichlorodiammineplatinum(II) was almost completely prevented by a 2-hour outpatient regimen of hydration and diuresis. A prospective randomized trial is planned comparing CHAD to melphalan in previously untreated women with advanced ovarian cancer.

Adult↗
PubMed1991

[Note on the lessons of rinderpest control in Chad since 1935].

The policy of rinderpest control in Chad has passed through various phases over sufficiently long periods to validate certain concepts such as that of the usefulness of perifocal vaccination of populations which have not been previously vaccinated. After studying the reliability of data regarding livestock, vaccinations and pathology and after having reviewed the various types of vaccine used, it can be concluded that perifocal vaccination, even in conjunction with the systematic vaccination of young, has not enabled rinderpest to be brought under control in Chad. Only systematic livestock vaccination can control and eradicate the disease. A table illustrates the vaccination operations and monitoring systems used.

Animals↗
PubMed1995

[Comparison of the pathogenic effect in mice between stocks of Trypanosoma evansi from Mauritania and from Kenya, Niger, Chad and China].

The pathogenicity to mice of a stock of Trypanosoma evansi from Mauritania has been compared to that of stocks from Kenya, Niger, Chad and China, using doses of 5.10(5), 2.10(6) and 5.10(6) trypanosomes per mouse. The survival of mice inoculated with stocks from Kenya, Niger and China is short, on average 2.1 to 6.5 days. Mice inoculated with stocks from Mauritania and Chad survive longer, 12.5 to 22.7 days, depending on the dose.

Animals↗
PubMed2025

Integrated Seroprevalence and Genome-Based Study of SARS-CoV-2 Viral Strains in N'Djamena: Insights Into Chad's COVID-19 Epicenter.

The COVID-19 epidemic has shown regional variations in transmission and outcomes. As a primary hotspot in Chad, N'Djamena is crucial for comprehensive epidemiological investigation. Our study employed two methodologies: seroprevalence data collection and whole-genome sequencing of SARS-CoV-2 strains. This dual approach assessed population exposure and virus genetic diversity. Seroprevalence data indicated broader exposure than confirmed cases suggested, and genome sequencing identified multiple strains, including globally recognized variants of concern. Integrating these data provided insights into transmission dynamics, potential herd immunity thresholds, and the impact of specific variants on disease progression. Our findings underscore the importance of integrated, multidisciplinary research in infectious disease epidemiology and inform targeted public health strategies, including social measures and vaccination, to combat infectious diseases in N'Djamena.

Humans↗
PubMed1979

[Preventive aspects and problems of a rural health project in Chad--the need for health motivation].

Some of the main difficulties encountered in health work in developing countries depend on the sociocultural conditions. Health animatiod until now) of rural health care. Its implementation requires the training and recycling of existing health personnel as well as of parts of the population. It includes the concept of "barefoot doctor", which corresponds well to the prevailing priority health needs. One should note potential difficulties, however, for example in regard to the way the barefoot doctor is to be remunerated (the author discusses some possibilities). It isn't easy either, in practice, to mobilize the community through health education and to obtain its participation in prevention and health promotion measures. The crucial element is to win its confidence. The author describes his practical experiences in Chad in this respect. Health animation stimulates the responsabilization and the development of a prospective outlook in people, and can thus make an important contribution to their overall development efforts. It is necessary to fight factors which slow down such an evolution, among which certain habits as well as obstacles of an administrative nature.

Chad↗
PubMed1995

The 1990 meningococcal meningitis epidemic of Sarh (Chad): how useful was an earlier mass vaccination?

A large outbreak of meningococcal meningitis (Serogroup A) occurred in southern Chad in 1990. We describe the epidemic in the town of Sarh, where a mass vaccination against meningococcal meningitis had taken place two years before, in 1988 (estimated coverage: 66%). Early warning that an epidemic was imminent was given at the end of February, following more than 15 recorded cases per 100,000 population on 3 consecutive weeks. This threshold proved to be adequate to predict the outbreak. A total of 721 cases were recorded at Sarh hospital and at a nearby health centre. Direct agglutination tests confirmed that Neisseria meningitis serogroup A was the only causative agent. The overall incidence rate in this population of 80,000 was 0.9%. The highest weekly incidence rate was 186 cases per 100,000 population. The mean age of the patients was 12.6 years and age-specific incidence rates ranged from 0.23% to 1.42%. The male/female sex ratio was 1.36. Overall, the mortality among hospitalized patients was 7.9%. Mortality increased during the epidemic. The major risk factor for dying was the delay until reaching hospital. Only 4 out of 29 interviewed parents said that their child had been vaccinated two years before. Among adult patients this proportion was 12/38 (32%). Because of the small numbers and because of the impossibility to check the vaccination records it was not possible to assess precisely the impact of earlier mass vaccination. However, the previous mass vaccination did not prevent this major epidemic and its impact is likely to have been unimportant.

Adolescent↗
PubMed1995

Priorities in global measles control: report of an outbreak in N'Djamena, Chad.

In N'Djamena, capital of Chad, measles vaccination coverage of 12-23-month-old children fell from 61% in 1990 to 15% in 1993. A community survey of measles after an outbreak in 1993 showed that among children < 5 years of age, the mean monthly attack rate was 37 per 1,000 (95% CI, 32-43) and the mean case fatality rate was 7.4%. Measles incidence was highest (77/1,000/month) in children aged 9-11 months and fell among children > 3 years of age. Incidence rates were high (56/1,000/month) among 6-8-month-old children, but only 3 deaths occurred in this age group. Measles vaccine efficacy, estimated by comparing attack rates in unvaccinated and vaccinated children, was 71% (95% CI, 59-80%). Extrapolation of the results to the city population indicated that an estimated 19,000 cases and > 1,000 measles-associated deaths occurred in 1993. This preventable morbidity and mortality, in a city where coverage was formerly among the highest in Africa, shows the need for sustained global commitment to preventive health care.

Age Distribution↗
PubMed1976

Blood polymorphism frequencies in the Sara Majingay of Chad.

Blood samples of 258 Sara Majingay of Ndila (Southern Chad) were analysed. Phenotype and allele frequencies are given for 22 polymorphisms. For each of these, the Majingay are compared to a number of other African populations. Then they are included in a set of 8 African populations between which multivariate distances for 25 alleles at 9 loci are computed. A two-dimensional representation is derived from the matrix of distances, and is discussed. It bears the stamp of gene flow in central Ethiopia, where an Arab admixture is evident, and in Southern Africa, where a reciprocal gene flow has marked the gene pools of Khoisan and Bantu speakers to a varying degree. The Majingay stand relatively near to the Bedik, another population of West-Central Africa. The non-Arab or non-Khoisan components of the gene pool of the other populations do not seem to differ largely from the gene pools of the West-Central African populations.

Acid Phosphatase↗
PubMed1990

[Hyperthyroidism in Chad and its treatment. 16 cases of which 10 were treated surgically in 1984-1985 in N'Djamena].

Sixteen patients with thyrotoxicosis were admitted during a period of eighteen months (1984-1985) in Central Hospital of N'Djamena (Chad). Clinical features, laboratory investigations are reported. Ten patients had a surgical treatment:subtotal thyroidectomy. A review of literature in Africa was made. Whereas thyrotoxicosis was rare among Africans before 1970, there has been an increase of frequency for twenty years. Many hypotheses are proposed, among them the possibility of the role of Epstein-Barr's virus, frequent in Africa.

Adolescent↗
PubMedDate not supplied

[Epidemiological aspects of human African trypanosomiasis in south Chad].

The authors are recording results of a clinical, parasitological and immunological sample survey about african human trypanosomiasis in the South Chad where old focus has been reexplored. In 1988 the situation ever remains as a problem in some areas (Tapol, Ranga) where high prevalence rates are found again.

Adolescent↗