Biomedical subjects

Delia Bethell

Publications and source records attributed to Delia Bethell.

7 recordsLinked to original sources

PubMed2005

Fatal Plasmodium falciparum malaria causes specific patterns of splenic architectural disorganization.

The spleen is critical for host defense against pathogens, including Plasmodium falciparum. It has a dual role, not only removing aged or antigenically altered erythrocytes from the blood but also as the major lymphoid organ for blood-borne or systemic infections. The human malaria parasite P. falciparum replicates within erythrocytes during asexual blood stages and causes repeated infections that can be associated with severe disease. In spite of the crucial role of the spleen in the innate and acquired immune response to malaria, there is little information on the pathology of the spleen in human malaria. We performed a histological and quantitative immunohistochemical study of spleen sections from Vietnamese adults dying from severe falciparum malaria and compared the findings with the findings for spleen sections from control patients and patients dying from systemic bacterial sepsis. Here we report that the white pulp in the spleens of patients dying from malaria showed a marked architectural disorganization. We observed a marked dissolution of the marginal zones with relative loss of B cells. Furthermore, we found strong HLA-DR expression on sinusoidal lining cells but downregulation on cordal macrophages. P. falciparum infection results in alterations in splenic leukocytes, many of which are not seen in sepsis.

Adult↗

PubMed2004

Impact of improved vaccination programme and intensive care facilities on incidence and outcome of tetanus in southern Vietnam, 1993-2002.

Unvaccinated individuals throughout the world are vulnerable to tetanus, but there are few data regarding the impact of focused vaccination programmes and modern intensive care facilities on the disease, particularly in the developing world. The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam admitted 2422 patients with tetanus aged > or =1 year between April 1993 and December 2002, during which time vaccine coverage and treatment facilities improved. The proportion of children < or =10 years old admitted with tetanus fell from 11.1 to 5.6% over the 10 year period (P = 0.002). The proportion of women aged 20-40 years fell from 10.1 to 1.2% (P < 0.001). Mortality rates fell from a maximum of 27.81% in 1994 to 10.04% in 2002 (P < 0.001). Thus, a marked reduction in tetanus incidence has occurred in age groups specifically targeted by the national vaccination programme. However, tetanus continues to be a major cause of morbidity and mortality in individuals outside the target population. Improved intensive care facilities, such as mechanical ventilation and low-cost infection control procedures are associated with a significant reduction in mortality.

Adolescent↗

PubMed2004

Resolution of orbitocerebral aspergillosis during combination treatment with voriconazole and amphotericin plus adjunctive cytokine therapy.

Orbitocerebral aspergillosis has a very high fatality rate and cure is unusual. We describe the successful management of a child with cereberal aspergillosis who had a dramatic response to therapy with a combination of liposomal amphotericin and voriconazole with adjunctive cytokine therapy during immunosuppresive chemotherapy for acute lymphoblastic leukaemia.

Amphotericin B↗

PubMed2004

Evaluation of an algorithm for integrated management of childhood illness in an area of Vietnam with dengue transmission.

OBJECTIVES: To determine whether nurses, using the WHO/UNICEF algorithm for integrated management of childhood illness (IMCI), modified to include dengue infection, satisfactorily classified children in an area endemic for dengue haemorrhagic fever (DHF). METHODS: Nurses assessed and classified, using the modified IMCI algorithm, a systematic sample of 1250 children aged 2 months to 10 years (n = 1250) presenting to a paediatric hospital in Dong Nai Province, Vietnam. Their classification was compared with that of a paediatrician, blind to the result of the nurses' assessment, which could be modified in the light of simple investigations, e.g. dengue serology. RESULTS: In children aged 2-59 months (n = 859), the nurses were able to classify, using the modified chart, the presenting illness in >99% of children and found more than one classification in 70%. For the children with pneumonia, diarrhoea, dengue shock syndrome, severe DHF and severe disease requiring urgent admission, the nurse's classification was >60% sensitive and >85% specific compared with that of the paediatrician. For the nurse's classification of DHF the specificity was 50-55% for the children <5 years and in children with definitive dengue serology. Alterations in the DHF algorithm improved specificity at the expense of sensitivity. CONCLUSION: Using the IMCI chart, nurses classified appropriately many of the major clinical problems in sick children <5 years in southern Vietnam. However, further modifications will be required in the fever section, particularly for dengue. The impact of using the IMCI chart in peripheral health stations remains to be evaluated.

Algorithms↗

PubMed2002

Axonal injury in cerebral malaria.

Impairment of consciousness and other signs of cerebral dysfunction are common complications of severe Plasmodium falciparum malaria. Although the majority of patients make a complete recovery a significant minority, particularly children, have sequelae. The pathological process by which P. falciparum malaria induces severe but usually reversible neurological complications has not been elucidated. Impairment of transport within nerve fibers could induce neurological dysfunction and may have the potential either to resolve or to progress to irreversible damage. Beta-amyloid precursor protein (beta-APP) immunocytochemistry, quantified using digital image analysis, was used to detect defects in axonal transport in brain sections from 54 Vietnamese cases with P. falciparum malaria. The frequency and extent of beta-APP staining were more severe in patients with cerebral malaria than in those with no clinical cerebral involvement. Beta-APP staining was often associated with hemorrhages and areas of demyelination, suggesting that multiple processes may be involved in neuronal injury. The age of focal axonal damage, as determined by the extent of the associated microglial response, varied considerably within tissue sections from individual patients. These findings suggest that axons are vulnerable to a broad range of cerebral insults that occur during P. falciparum malaria infection. Disruption in axonal transport may represent a final common pathway leading to neurological dysfunction in cerebral malaria.

Adult↗

PubMed2002

Meningococcal vaccines.

The successful introduction of a protein-polysaccharide conjugate vaccine against serogroup C meningococci into the UK infant immunization schedule, in combination with a catch-up campaign for individuals less than 18 years of age, has seen virtually all group C disease eliminated in childhood. From being a devastating disease with a very high mortality, the possibility of eradicating invasive meningococcal disease now seems eminently feasible. Since similar technology is likely to facilitate prevention of disease caused be serogroup A, Y and W135 meningococci, the major hurdle in achieving the goal of eradication is development of a safe and immunogenic vaccine against serogroup B infections. Outer membrane vesicle vaccines remain in development and further trials are anticipated. Through the recent availability of the meningococcal genome sequence, many new vaccine candidates are being identified and there is increasing optimism that a solution to the problem can be found.

Animals↗

PubMed2002

Susceptibility to dengue hemorrhagic fever in vietnam: evidence of an association with variation in the vitamin d receptor and Fc gamma receptor IIa genes.

Dengue is an increasingly important cause of morbidity and mortality in the tropics, with more than a billion people at risk each year. Immunologic enhancement is thought to contribute to disease pathogenesis. Only a very small proportion of infected individuals develop life-threatening dengue hemorrhagic fever (DHF). In a large case-control study with 400 DHF patients and 300 matched controls, we have assessed five polymorphic non-HLA host genetic factors that might influence susceptibility to DHF. The less frequent t allele of a variant at position 352 of the vitamin D receptor (VDR) gene was associated with resistance to severe dengue (P = 0.03). Homozygotes for the arginine variant at position 131 of the Fc gammaRIIA gene, who have less capacity to opsonize IgG2 antibodies, may also be protected from DHF (one-tailed P = 0.03). No associations were found with polymorphisms in the mannose binding lectin, interleukin-1 (IL-4), and IL-1 receptor antagonist genes. Further studies to confirm these associations are warranted.

Base Sequence↗