Biomedical subjects
Publications and source records attributed to A M Elliott.
Exposure to infections in infancy may induce a sustained bias in the immune response. In our study, previous BCG immunisation was associated with a reduced prevalence of intestinal nematode infection.
We describe a woman with dyskeratosis congenita (DKC), microcephaly, and a purple discoloration of the tongue. The latter findings are not commonly described in males with DKC, have been reported in another female patient with this condition, and may represent the phenotype of an autosomal recessive entity of DKC. Results of X chromosome inactivation studies did not support X-linked DKC in our family. The additional findings of an affected brother and parental consanguinity support the hypothesis of autosomal recessive inheritance.
SETTING: Out-patient clinic, Entebbe, Uganda. BACKGROUND: It has been proposed that 'type 1' cytokines are essential in protective immunity to Mycobacterium tuberculosis and that suppression of 'type 1' or a switch to a 'type 2' profile is deleterious. We employed a simple assay to examine whether the dependence of the immunological responses to mycobacterial antigens on a range of explanatory factors could be determined in a population where tuberculosis is endemic. OBJECTIVE: To determine the relationship between the tuberculin skin test response and cytokine profile, and the effect of human immunodeficiency virus (HIV) infection. DESIGN: A cross-sectional study of 97 Ugandan adults (22 HIV-positive, 75 HIV-negative). Whole blood was stimulated in vitro using mycobacterial antigens (purified protein derivative [PPD] and culture filtrate proteins [CFP]). 'Type 1' cytokines (gamma interferon [IFN-gamma] and interleukin-2 [IL-2]), 'type 2' cytokines (IL-5 and IL-10) and tumour necrosis factor alpha (TNF-alpha) were measured in culture supernatants. RESULTS: Among HIV-negative subjects, a positive tuberculin skin test was associated with type 1 or mixed (type 1 + type 2) cytokine production, but a positive IFN-gamma response also occurred in a proportion of tuberculin skin test negative subjects (36% for PPD, 17% for CFP). In association with HIV infection, IFN-gamma responses to mycobacterial antigens were profoundly impaired (odds ratio [OR] 0.10 for PPD, 0.06 for CFP, P< or =0.001), but production of IL-2, IL-5 and TNF-alpha was relatively sustained, and IL-10 increased or sustained (OR 3.97 for PPD, P = 0.01, 1.14 for CFP, P = 0.99). CONCLUSION: The type 1/type 2 cytokine balance was not defined by the tuberculin skin test response, and may have a closer relation to protective immunity. IFN-gamma production was strikingly impaired in association with HIV infection, while production of type 2 cytokines was sustained or increased. Use of a simple assay allowed a large sample of subjects to be examined, producing epidemiologically meaningful results.
BACKGROUND: A randomized double-blind placebo-controlled trial was conducted to estimate the efficacy of preventive therapy for tuberculosis (TB) in HIV-infected adults in Lusaka, Zambia. The main outcome measures were the incidence of TB, mortality and adverse drug reactions. METHODS: During a 2 year period, 1053 HIV-positive individuals without evidence of clinical TB were randomly assigned to receive 6 months of isoniazid twice a week (H), or 3 months of rifampicin twice a week (R) plus pyrazinamide (Z), or a placebo. Therapy was taken twice a week and was self administered. Subjects presenting with symptoms during the follow-up period were investigated for TB. RESULTS: The 1053 subjects in the study were followed up for a total of 1631 person-years (median = 1.8 years). Twenty-nine subjects were taken off treatment as a result of adverse drug reactions. A total of 96 cases of TB/probable TB (59 TB and 37 probable TB) were diagnosed during the study period and 185 deaths were reported. One hundred and fifteen subjects (11%) did not return to the study clinic at any time after enrolment. The incidence of TB was lower in those subjects on preventive therapy (H and RZ groups combined) compared with those on placebo (rate ratio = 0.60, 95% CI: 0.36-1.01, P = 0.057), as was the incidence of TB/probable TB (rate ratio = 0.60, 95% CI: 0.40-0.89, P = 0.013). The effect of preventive therapy was greater in those with a tuberculin skin test (TST) of 5 mm or greater, in those with a lymphocyte count of 2x10(9)/l or higher, and in those with haemoglobin of 10 g/dl or higher. There was no difference in mortality rates between the preventive therapy and placebo groups. The effect of preventive therapy declined after the first year of the study so that by 18 months the rates of TB in the treated groups were similar to that in the placebo group. CONCLUSION: This study has demonstrated that preventive therapy with either twice weekly isoniazid for 6 months or a combination of rifampicin and pyrazinamide for 3 months reduced the incidence of TB in HIV-infected persons in Zambia. No effect was observed on mortality. The effect was greatest in persons who had a positive TST or a lymphocyte count of 2x10(9)/l or greater, indicating that preventive therapy may be more effective in people with less advanced immunosuppression. The limited duration of the protective effect reported in this study raises the question of the need for lifelong preventive therapy or re-prophylaxis.
We have studied two brothers with submicroscopic 22q11 deletion. One brother had findings suggestive of DiGeorge syndrome, while the other had milder anomalies, including polydactyly. Fluorescence in situ hybridization (FISH) showed a minor cell line with deletion 22q11 in the mother. To our knowledge, this is the first report of a deletion of 22q11 in two sibs with different phenotypes and apparent maternal mosaicism detected with FISH. This family illustrates the variability of the syndrome and further demonstrates the possibility of gonadal mosaicism for a microdeletion. Prenatal diagnosis may be offered after the birth of a child with a 22q11 deletion, even in the absence of parental chromosomal anomalies.
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Neopterin is a biochemical marker for the activation of the cell-mediated immune system. We measured neopterin, beta 2-microglobulin, and acute phase proteins in 31 HIV-seropositive and -seronegative Zambian patients with tuberculosis, using stored sera that had been obtained at the beginning and at end of antituberculosis treatment. In both HIV-seropositive and -seronegative patients neopterin and acute phase proteins were elevated when tuberculosis was initially diagnosed and fell during treatment. In contrast, the mean beta 2-microglobulin level increased during antituberculous therapy in the HIV-seropositive group. Serum neopterin levels at diagnosis were correlated with other parameters of disease activity (fever, anemia, and weight loss). In both groups, patients with persistently elevated neopterin levels at the end of treatment were more likely to suffer relapse of tuberculosis or other adverse health events in the subsequent follow-up period. Neopterin can be used to monitor the response to antituberculous therapy in both HIV-seropositive and -seronegative patients and may have a prognostic value for the patients' wellbeing in the follow-up period.
We report on a child with microcephaly, small facial and body size, and immune deficiency. The phenotype is consistent with Nijmegen breakage syndrome (NBS), with additional clinical manifestations and laboratory findings not reported heretofore. Most investigations, including the results of radiation-resistant DNA synthesis, concurred with the diagnosis of NBS. Cytogenetic analysis documented abnormalities in virtually all cells examined. Along with the high frequency of breaks and rearrangements of chromosomes 7 and 14, we found breakage and monosomies involving numerous other chromosomes. Because of some variation in the clinical presentation and some unusual cytogenetic findings, we suggest that our patient may represent a new variant of Nijmegen breakage syndrome.
We describe a female patient with multiple anomalies suggestive of a new syndrome. Manifestations include: VSD and ASD, mild developmental delay, conductive hearing loss, minor facial anomalies, thrombocytopenia, and radiological findings (including carpal fusion). Some of these manifestations may be present in the Keutel syndrome, IVIC syndrome, and the 10qter deletion syndrome. However, none of these syndromes can explain the spectrum of anomalies seen in our patient.
We describe a combination of multiple congenital anomalies, severe psychomotor retardation and symmetrical circumferential skin creases of arms and legs in a 4.5-year-old male. Craniofacial anomalies included: a high forehead, elongated face, bitemporal sparseness of hair, broad eyebrows, blepharophimosis, bilateral microphthalmia and microcornea, severe optic nerve hypoplasia, epicanthic folds, telecanthus, broad nasal bridge, puffy cheeks, microstomia, cleft palate, enamel hypoplasia, micrognathia, microtia with stenotic ear canals and posteriorly angulated ears. Head circumference was on the 10th centile and a CT scan showed dilated lateral ventricles. Intracranial pressure was not increased. Other abnormalities included: short stature, loose skin, hypotonia, pectus excavatum, inguinal and umbilical hernias, severe scoliosis, hypoplastic scrotum, long fingers and overlapping toes. Echocardiography showed tricuspid regurgitation. Chromosomes were apparently normal. Differentiation from "Michelin tire baby syndrome" and amniotic band sequence is discussed.
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We describe a male infant with findings typical of Schinzel-Giedion syndrome. Characteristic features include: midface retraction, widely patent fontanelles, hirsutism, choanal stenosis, hypospadias with chordae, club feet and broad ribs. The patient suffered from seizures and died at 14 months of age of fulminant bronchopneumonia. Pathological examination revealed steatosis in the liver as well as lipid vacuolization of the zona fasciculata of the adrenals.
Interactions between intracellular bacterial pathogens and their eukaryotic cellular hosts or targets are often studied with fluorescence-based techniques such as fluorescence microscopy and flow cytometry. We tested whether the intracellular bacterial pathogens L. monocytogenes, M. avium, M. tuberculosis, and S. typhimurium could be labeled by growth in broth containing the fluorochromes carboxy-X-rhodamine (CR), a hydrazine derivative of fluorescein (FH), and Lucifer Yellow CH (LY). Only Listeria were labeled by all three fluorochromes, Salmonella took up only FH, whereas M. avium and M. tuberculosis were labeled by FH and LY. In general, the fluorochromes did not affect bacterial growth or viability, although FH inhibited the growth of M. tuberculosis. Fluorescent Listeria and M. tuberculosis were used to demonstrate that FH- and LY-labeled bacteria were bright enough after phagocytosis by macrophages to distinguish phagocytic from nonphagocytic cells by flow cytometry. To test whether the fluorochromes might alter bacterial interactions with host cells, we measured both phagocytosis of fluorescent Listeria by macrophages and subsequent bacterial replication in these cells. In these experiments, labeled and unlabeled Listeria were phagocytosed similarly by macrophages and were not impaired in their ability to replicate within them. Thus, this method for fluorescence labeling of bacteria is useful for studying physiologic macrophage:bacteria interactions.
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We describe a 21-week-old fetus with a pattern of multiple congenital anomalies suggestive of the human homologue of the mouse mutant disorganization (Ds). Manifestations included facial asymmetry, thick eye brows, micrognathia, apparently lowset ears, an enormous abdominal wall defect, severe kyphoscoliosis, camptodactyly of the fingers, complete absence of the left lower limb, and absence of the lower part of the sacrum and coccyx, as well as left side of the pelvis. There was a disorganized appearance of the right foot with supernumerary digits and appendages and talipes equinovarus. No obvious amniotic bands or oligohydramnios were noted. Similar cases in the literature are reviewed and the clinical significance to genetic counselling is emphasized.