Healing the Children: medical missions

In 1993, I started documenting medical missions organised by the American-based, non-profit organisation Healing the Children (HTC). With 14 chapters in 21 states, HTC has helped tens of thousands of children worldwide since it was founded in 1979. The organisation arranges specialised medical treatment and surgical care for children whose families cannot afford it or whose communities do not offer it. HTC relies entirely on volunteers. In 1995, the northeast chapter of HTC alone provided more than $7.5 million in services to about 2300 children. HTC also provides treatment and assistance to disadvantaged children in US communities, arranges special care in the USA for children from nearly 60 countries, and recruits organisations to provide supplies and refurbished equipment to hospitals in underdeveloped countries. In October, 1994, I travelled with an HTC team of over 50 medical personnel on a cardiac trip to Guatemala City. More recently, in April, 1996, I documented a team of 11 who travelled to Cochahamba, Bolivia, to carry out soft tissue surgery.

A volumetric approach to virtual simulation of functional endoscopic sinus surgery

Advanced display technologies have made the virtual exploration of relatively complex models feasible in many applications. Unfortunately, only a few human interfaces allow natural interaction with the environment. Moreover, in surgical applications, such realistic interaction requires real-time rendering of volumetric data-placing an overwhelming performance burden on the system. We report on a collaboration of an interdisciplinary group developing a virtual reality system that provides intuitive interaction with volume data by employing real-time volume rendering and force feedback (haptic) sensations. We describe our rendering methods and the haptic devices and explain its utility of this system in the real-world application of Endoscopic Sinus Surgery (ESS) simulation.

Variation in the tumor necrosis factor-alpha gene promoter region may be associated with death from meningococcal disease

Tumor necrosis factor-alpha (TNF-alpha) plays a central role in the pathophysiology of sepsis. Levels of TNF-alpha are directly correlated with severity in meningococcal disease (MD). A polymorphism in the promoter region of the TNF-alpha gene is associated with differences in the secretion of TNF-alpha. The TNF2 allele is associated with higher constitutive and inducible levels of TNF-alpha secretion than is the TNF1 allele. To investigate whether possession of the TNF2 allele is associated with severity in MD, the frequency of TNF1 and TNF2 alleles in 98 children with MD was compared. There were more deaths among children who had the TNF2 allele (P = .03; relative risk [RR], 2.5; 95% confidence interval [CI], 1.1-5.7) than in those who did not. There was also an increased risk of severe disease in children with the TNF2 allele (P = .02; RR, 1.6; 95% CI, 1.1-2.3). Possession of the TNF2 allele predisposes to a worse outcome in children with meningococcal infection.

Demographic characteristics of the population of Greater Soweto, 1993

"This research note provides information and findings on some aspects of urbanisation in Greater Soweto. It outlines the demographic characteristics of the population, namely the characteristics of households; household preferences for services; perceptions on accommodation; age and gender profiles; education levels; the origin of the inhabitants and mobility in and migration to Greater Soweto. Some findings are particularly important for future planning of services and low-income or subsidised housing."

Acute tumor lysis syndrome in high grade lymphoblastic lymphoma after a prolonged episode of fever

Acute tumor lysis syndrome occurs in rapidly growing lymphoid malignancies, usually as a consequence of chemotherapy or corticosteroids. We present what appears to be the first reported case of tumor lysis occurring after a sustained episode of high fever of 42.0 degrees C in a patient with high grade lymphoblastic lymphoma and a high tumor burden.

Serological evidence for zoonotic hantaviruses in North Carolina rodents

In a survey of seven species of wild rodents (n = 423) collected between October 1993 and March 1994 from the three principal ecological biomes of North Carolina (USA), we found hantavirus antibodies in seven (2%) of 301 Peromyscus spp. Hantavirus antibodies were detected in P. leucopus and P. maniculatus captured from mountain and coastal island biomes. Three mice were positive for Sin Nombre virus, while four others had antibodies to Seoul virus or a related agent. Two mice serologically positive for Sin Nombre virus were collected from inside a private mountain domicile. We conclude that the risk of human exposure to hantaviruses in North Carolina resembles that for most other areas of the continental United States.

Translocation (3;3) in a patient with thrombocytopenia and erythroid dysplasia

We describe a case with a translocation between the two chromosomes 3 with breakpoints q21 and q26, associated with a unique constellation of hematologic abnormalities. Megakaryocytic dysplasia and peripheral thrombocytosis are the most common abnormalities associated with this chromosome abnormality. Our patient had acute myeloid leukemia (AML), thrombocytopenia, dyserythropoiesis, and an increased myeloid/erythroid ration but no mekakaryocytic dysplasia. Although multilineage involvement has been reported, erythrocyte dysplasia associated with thrombocytopenia and without megakaryocyte dysplasia appears to be extremely rare. Our case supports the speculation that #3 abnormalities with breakpoints q21 and q26 affect a pluripotent stem cell and suggests that megakaryocytic involvement may not be pathognomonic in hematologic abnormalities with t(3;3)(q21;26).

Systemic complications associated with bacterial tracheitis

The toxic shock syndrome, septic shock, pulmonary oedema, and the acute respiratory distress syndrome (ARDS) were recognised in four children with bacterial tracheitis. ARDS has not previously been reported in association with bacterial tracheitis. Prompt recognition of the severe systemic complications of bacterial tracheitis could lead to a decrease in the morbidity and mortality of this condition.

The influence of capsulation and lipooligosaccharide structure on neutrophil adhesion molecule expression and endothelial injury by Neisseria meningitidis

Host inflammatory response to meningococcal infection is believed to be a major determinant of disease severity. Isogenic mutants of Neisseria meningitidis serogroup B1940, which differ in expression of capsular polysaccharide and lipooligosaccharide (LOS), were used to examine host responses in a whole blood model of bacteremia and a model of endothelial injury. The parent organism caused significantly less neutrophil shedding of the adhesion molecule, L-selectin, than the three mutant organisms (P < .01) and was most resistant to the bactericidal activity of whole blood. Despite marked differences in bacterial adhesion to endothelial cells (P < .05), no damage was induced by organisms alone. Endothelial injury was observed when neutrophils were incubated with adherent, capsule-deficient organisms (P < .05). The degree of endothelial damage was related to the number of neutrophils adherent to the endothelium. Thus, bacterial capsulation and LOS structure can influence neutrophil activation and endothelial injury and, as such, may be important in the pathogenesis of meningococcal sepsis.

Assessment of the effect of candidate anti-inflammatory treatments on the interaction between meningococci and inflammatory cells in vitro in a whole blood model

A wide range of immunomodulating agents are now available which may be of benefit in reducing inflammatory cell activation in meningococcal sepsis. In order to facilitate selection of candidate anti-inflammatory agents for clinical trials, we have used an in vitro whole blood model to evaluate the effects on meningococcal induced neutrophil and monocyte activation, of dexamethasone, prostacyclin, pentoxifylline and a human IgM anti-lipid A monoclonal antibody (HA-1A). Known concentrations of heat and penicillin killed meningococci were added to whole blood and the time course of cellular activation was determined. Using elastase alpha 1-antitrypsin (elastase-alpha 1-AT) and TNF alpha production as markers of neutrophil and monocyte activation respectively, plasma levels of elastase-alpha 1-AT and TNF alpha were found to increase in a dose-dependent manner. Elastase-alpha 1-AT was detected early, with most release occurring between 15-30 min whereas TNF alpha was detected later, between 120-180 min. Dexamethasone, prostacyclin and pentoxifylline caused a dose-dependent inhibition of TNF alpha release but had no effect on elastase release. HA-1A had no effect on either TNF alpha or elastase release. This model may be useful in determining the sequence of inflammatory cell activation and in selecting candidate anti-inflammatory agents for evaluation in clinical trials.

Defective antigen processing associated with familial disseminated mycobacteriosis

To gain insights into a possible immune defect predisposing to disseminated mycobacteria infection, we studied three of six surviving children with disseminated Mycobacterium avium complex infection, who had no recognized form of immunodeficiency. We used mycobacteria isolated from the patients and diphtheria, tetanus and pertussis vaccine (DTP) to study antigen-specific T lymphocyte responses. We observed that interferon-gamma (IFN-gamma) production by T cells in response to antigens (both mycobacteria and DTP) in these patients with disseminated infection was greatly impaired. This defect did not seem to be the result of T cell unresponsiveness, as phytohaemagglutinin (PHA) stimulation was able to induce high levels of IFN-gamma comparable to those seen in control patients with localized infection. Further experiments showed that peripheral blood mononuclear cells (PBMC) from patients with disseminated infection were able to present influenza haemagglutinin (HA) peptides to specific T cell clones. However, this ability was lost when the whole HA protein was used as source of antigen. Taken together, these observations support the notion that the primary immune defect in these patients with disseminated mycobacterial infection rests in the antigen-processing functions of their antigen-presenting cells (APC). These findings may provide clues to the wider problem of susceptibility to mycobacteria and other intracellular pathogens and have implications in designing therapy for these patients.

Reservoir competence of the southeastern five-lined skink (Eumeces inexpectatus) and the green anole (Anolis carolinensis) for Borrelia burgdorferi

The reservoir competence of two lizard species, the southeastern five-lined skink (Eumeces inexpectatus) and the green anole (Anolis carolinesis), for Borrelia burgdorferi was evaluated. Skinks and anoles were exposed by needle inoculation or tick bite to B. burgdorferi. Xenodiagnosis with larval Ixodes scapularis and culture of tissues were used to asses infection and the ability of infected lizards to infect attached ticks. Both lizard species were susceptible to B. burgdorferi by both routes of exposure. Xenodiagnostic ticks acquired spirochetes while feeding on both species. One tick that dropped from a skink on the ninth day after exposure was infected. The remainder of xenodiagnostic ticks that acquired spirochetes fed three weeks after exposure of the lizards to the spirochete. Lizards remained infectious to attached ticks for at least five weeks. Overall, more than 20% of xenodiagnostic larvae fed on southeastern five-lined skinks acquired spirochetes. Individual skinks infected up to 34% of attached ticks. A smaller proportion of ticks feeding on green anoles became infected. Borrelia burgdorferi recovered from infected lizards retained their infectivity for mammalian hosts. The ability of the lizards to sustain a Borrelia infection and infect attached ticks suggests that they may play a role in the maintenance of spirochete transmission.

Cytokine production in varicella-zoster virus-stimulated lymphocyte cultures

Among varicella-zoster virus (VZV)-immune adults aged 20 to 35 years, T lymphocytes producing interferon-gamma (IFN-gamma) in response to a VZV antigen stimulus are eight times more numerous than those making interleukin-4 (IL-4). In persons over 55 years old, the frequency of IFN-gamma-making cells falls while the number of IL-4-making cells remains roughly constant. The persistence of IL-4-making cells may contribute to the maintenance of IgG antibodies to VZV with aging.

Evidence for exclusion of a mutation in NRAMP as the cause of familial disseminated atypical mycobacterial infection in a Maltese kindred

In mice, susceptibility to intracellular infections in inbred strains is controlled by a single locus, Lsh/Ity/Bcg, and the gene responsible has been cloned and designated Nramp (Natural resistance associated macrophage protein). We have identified a group of related children who appear to have a single gene defect, inherited recessively, which results in increased susceptibility to myocabacterial infection. The immunological defect observed in the affected children resembles that in mice homozygous for the Lsh/Ity/Bcg susceptible allele. To test the hypothesis that a mutation in NRAMP is responsible for the immunodeficiency observed in the affected children, we have typed eight markers in the region of human 2q34-q37 where NRAMP, the human homologue of Nramp, maps. We have shown discordance with the defect in one family and the chromosomes in the three affected children have different haplotypes making it unlikely that inheritance of an ancestral mutation in the NRAMP gene is the cause of increased mycobacterial susceptibility in this group of children.

Unusual lytic intraosseous meningioma

Lytic intraosseous meningiomas are rare. This unusual case presented a diagnostic and treatment challenge.

Morbidity and severity of illness during interhospital transfer: impact of a specialised paediatric retrieval team

OBJECTIVE

To evaluate the morbidity and severity of illness during interhospital transfer of critically ill children by a specialised paediatric retrieval team.

DESIGN

Prospective, descriptive study.

SETTING

Hospitals without paediatric intensive care facilities in and around the London area, and a paediatric intensive care unit at a tertiary centre.

SUBJECTS

51 critically ill children transferred to the paediatric intensive care unit.

MAIN OUTCOME MEASURES

Adverse events related to equipment and physiological deterioration during transfer. Paediatric risk of mortality score before and after retrieval. Therapeutic intervention score before and after arrival of retrieval team.

RESULTS

Two (4%) patients had preventable physiological deterioration during transport. There were no adverse events related to equipment. Severity of illness decreased during stabilisation and transport by the retrieval team, suggested by the difference between risk of mortality scores before and after retrieval (P < 0.001). The median (range) difference between the two scores was 3.0 (-6 to 17). Interventions during stabilisation by the retrieval team increased, demonstrated by the difference between intervention scores before and after retrieval, median (range) difference between the two scores being 6 (-8 to 38) (P < 0.001).

CONCLUSIONS

Our study indicates that a specialised paediatric retrieval team can rapidly deliver intensive care to critically ill children awaiting transfer. Such children can be transferred to a paediatric intensive care unit with minimal morbidity and mortality related to transport. There was no deterioration in the clinical condition of most patients during transfer.