Devil Facial Tumor Disease

Devil facial tumor disease (DFTD) is an emergent transmissible cancer exclusive to Tasmanian devils (Sarcophilus harrisii) and threatening the species with extinction in the wild. Research on DFTD began 10 years ago, when nothing was known about the tumor and little about the devils. The depth of knowledge gained since then is impressive, with research having addressed significant aspects of the disease and the devils' responses to it. These include the cause and pathogenesis of DFTD, the immune response of the devils and the immune evasion mechanisms of the tumor, the transmission patterns of DFTD, and the impacts of DFTD on the ecosystem. This review aims to collate this information and put it into the context of conservation strategies designed to mitigate the impacts of DFTD on the devil and the Tasmanian ecosystem.

Evidence for induction of humoral and cytotoxic immune responses against devil facial tumor disease cells in Tasmanian devils (Sarcophilus harrisii) immunized with killed cell preparations

Tasmanian devils (Sarcophilus harrisii) risk extinction from a contagious cancer, devil facial tumour disease (DFTD) in which the infectious agent is the tumor cell itself. Because devils are unable to produce an immune response against the tumor cells no devil has survived 'infection'. To promote an immune response we immunized healthy devils with killed DFTD tumor cells in the presence of adjuvants. Immune responses, including cytotoxicity and antibody production, were detected in five of the six devils. The incorporation of adjuvants that act via toll like receptors may provide additional signals to break 'immunological ignorance'. One of these devils was protected against a challenge with viable DFTD cells. This was a short-term protection as re-challenge one year later resulted in tumor growth. These results suggest that Tasmanian devils can generate immune responses against DFTD cells. With further optimization of immune stimulation it should be possible to protect Tasmanian devils against DFTD with an injectable vaccine.

Dietary vitamin D alters the response of the skin to UVB-irradiation depending on the genetic background of the mice

Ultraviolet B (UVB) irradiation of the skin has the benefit of causing the local production of previtamin D3 but also results in cutaneous DNA damage and suppression of the skin immune system (SIS). Strains of mice differ in their ability to be suppressed by UVB irradiation: BALB/c mice are considered "resistant" and C57BL/6 "sensitive". This study evaluated whether vitamin D-replete (D+) and deficient (D-) BALB/c and C57BL/6 mice differed in their cutaneous response to UVB irradiation. Immunosuppression was assessed by measuring the contact hypersensitivity (CHS) response, DNA damage and repair determined by counting thymine dimer positive keratinocyte nuclei, and cutaneous inflammation and epidermal hyperplasia evaluated by light microscopy. The suppression in the CHS response induced by the UVB irradiation was reduced in the D+ C57BL/6 mice compared with the D- C57BL/6 mice. Similarly there was a reduction in DNA damage and promotion of its repair in the D+ C57BL/6 mice compared with the D- C57BL/6 mice. A reduction in inflammation in female D+ C57BL/6 mice compared with D- C57BL/6 females also occurred. In contrast, the suppression in the CHS response, DNA damage and its repair, and inflammation induced by UVB irradiation were similar in the D+ and D- BALB/c mice. These results indicate that dietary vitamin D3 can reduce UVB-induced suppression of the CHS response depending on the genetic background of the mice, an effect that may relate to the reduction in DNA damage and an increase in its rate of repair.

Tumor-Specific Diagnostic Marker for Transmissible Facial Tumors of Tasmanian Devils

Devil facial tumor disease (DFTD) is a transmissible neoplasm that is threatening the survival of the Tasmanian devil. Genetic analyses have indicated that the disease is a peripheral nerve sheath neoplasm of Schwann cell origin. DFTD cells express genes characteristic of myelinating Schwann cells, and periaxin, a Schwann cell protein, has been proposed as a marker for the disease. Diagnosis of DFTD is currently based on histopathology, cytogenetics, and clinical appearance of the disease in affected animals. As devils are susceptible to a variety of neoplastic processes, a specific diagnostic test is required to differentiate DFTD from cancers of similar morphological appearance. This study presents a thorough examination of the expression of a set of Schwann cell and other neural crest markers in DFTD tumors and normal devil tissues. Samples from 20 primary DFTD tumors and 10 DFTD metastases were evaluated by immunohistochemistry for the expression of periaxin, S100 protein, peripheral myelin protein 22, nerve growth factor receptor, nestin, neuron specific enolase, chromogranin A, and myelin basic protein. Of these, periaxin was confirmed as the most sensitive and specific marker, labeling the majority of DFTD cells in 100% of primary DFTD tumors and DFTD metastases. In normal tissues, periaxin showed specificity for Schwann cells in peripheral nerve bundles. This marker was then evaluated in cultured devil Schwann cells, DFTD cell lines, and xenografted DFTD tumors. Periaxin expression was maintained in all these models, validating its utility as a diagnostic marker for the disease.

A Murine Xenograft Model for a Transmissible Cancer in Tasmanian Devils

The number of Tasmanian devils in the wild is rapidly declining owing to a transmissible cancer, devil facial tumor disease (DFTD). Although progress has been made to understand the spread of this disease, crucial research on the pathogenesis of DFTD has been limited because of the threatened status of the host species. Here, the authors describe the development of a NOD/SCID (nonobese diabetic / severe combined immunodeficiency) mouse model that reproduces DFTD and provides a much-needed model to undertake studies into this intriguing transmissible cancer. Histologically, the DFTD produced in NOD/SCID mice (xenografted DFTD) was indistinguishable from the DFTD identified in Tasmanian devils. At the protein level, all xenografted DFTD tumors expressed periaxin, a marker that confirmed the diagnosis of DFTD. The karyotype of DFTD in NOD/SCID mice reproduced similar chromosomal alterations as seen in diseased devils. Furthermore, each NOD/SCID mouse inoculated with cultured DFTD tumor cells developed tumors, whereas DFTD did not develop in any of the inoculated immune-competent BALB/c mice.

Mitogen-induced responses in lymphocytes from platypus, the Tasmanian devil and the eastern barred bandicoot

OBJECTIVE

As the platypus (Ornithorhynchus anatinus), the Tasmanian devil (Sarcophilus harrisi) and the eastern barred bandicoot (Perameles gunni) are currently at risk of serious population decline or extinction from fatal diseases in Tasmania, the goal of the present study was to describe the normal immune response of these species to challenge using the lymphocyte proliferation assay, to give a solid basis for further studies.

METHODS

For this preliminary study, we performed lymphocyte proliferation assays on peripheral blood mononuclear cells (PBMC) from the three species. We used the common mitogens phytohaemagglutinin (PHA), concanavalin A (ConA), lipopolysaccharide (LPS) and pokeweed mitogen (PWM).

RESULTS

All three species recorded the highest stimulation index (SI) with the T-cell mitogens PHA and ConA. Tasmanian devils and bandicoots had greater responses than platypuses, although variability between individual animals was high.

CONCLUSION

For the first time, we report the normal cellular response of the platypus, the Tasmanian devil and the eastern barred bandicoot to a range of commonly used mitogens.

Proteomics identifies enhanced expression of stefin A in neonatal murine skin compared with adults: functional implications

BACKGROUND

Skin develops through a process of epidermal proliferation, maturation, and remodelling of the epidermis and dermis. This period also involves the maturation of the skin immune system, such that antigen applied though the skin of a neonatal mouse always results in immunosuppression, whereas in adults, immunity will occur.

OBJECTIVES

Using proteomics, to identify proteins uniquely involved in the development of the skin and skin immune system.

METHODS

Proteins were extracted from whole skin of mice aged 4 and 21 days, and separated using two-dimensional electrophoresis.

RESULTS

Of the 25 proteins that were sequenced by peptide mass fingerprinting with matrix-assisted laser desorption/ionization-time of flight-mass spectrometry, three were known markers of keratinocyte differentiation and proliferation. These were cyclophilin A, epidermal fatty acid binding protein 5 and stefin A. Of interest were the two isoforms of stefin A, an intracellular protease inhibitor, found in neonatal skin. The strong expression of stefin A in neonates was confirmed by immunohistochemical analysis, suggesting an important role in the development of the epidermis. Additionally, Western blotting identified two larger isoforms in adult skin, revealing a change in the stefin A during development.

CONCLUSIONS

We propose that stefin A is involved in development of the skin, that development of the skin and of immune function is linked, and that stefin A has an important function in neonatal skin and potentially the neonatal immune response.

An influx of macrophages is the predominant local immune response in ovine pulmonary adenocarcinoma

Infection with a retrovirus, Jaagsiekte sheep retrovirus (JSRV), causes ovine pulmonary adenocarcinoma (OPA). The excess production of surfactant proteins by alveolar tumour cells results in increased production of pulmonary fluid, which is characteristically expelled through the nostrils of affected sheep. The immune response to JSRV and the tumour is poorly understood: no JSRV-specific circulating antibodies or T cells have been detected to date. The aim of the present study was to obtain phenotypic evidence for a local immune response in OPA lungs. Specific-pathogen free lambs were infected intratracheally with JSRV. When clinical signs of OPA were apparent, the lungs were removed at necropsy and immunohistochemistry (IHC) was performed on lung sections using a panel of mouse anti-sheep mAbs. No influx of dendritic cells, B cells, CD4, CD8 or gammadelta T cells was seen in the neoplastic nodules or in their periphery. MHC Class II-positive cells were found intratumourally, peritumourally and in the surrounding alveolar lumina. In the tumours, many of these cells were shown to be fibroblasts and the remainder were likely to be mature macrophages. In the alveolar lumen, the MHC Class II-positive cells were CD14-positive and expressed high levels of IFN-gamma. They appeared to be immature monocytes or macrophages which then differentiated to become CD14-negative as they reached the periphery of the tumours. A high level of MHC Class I expression was detected on a range of cells in the OPA lungs but the tumour nodules themselves contained no MHC Class I-positive cells. On the basis of these findings, it is proposed that the lack of an effective immune response in OPA could result from a mechanism of peripheral tolerance in which the activity of the invading macrophages is suppressed by the local environment, possibly as a consequence of the inhibitory properties of the surfactant proteins.

In vitro testing to diagnose venom allergy and monitor immunotherapy: a placebo-controlled, crossover trial

BACKGROUND

In people with a history of sting allergy, only prior reaction severity and older age are known to predict subsequent reaction risk. Furthermore, no diagnostic test other than a deliberate sting challenge has been found to identify people in whom venom immunotherapy (VIT) has been unsuccessful.

OBJECTIVE

We aimed to assess the utility of a number of in vitro tests to diagnose venom allergy and to monitor immunotherapy.

METHODS

During a double-blind randomized placebo-controlled crossover trial of Myrmecia pilosula ant VIT the following venom-specific tests were performed at enrolment, and at completion of treatment prior to a diagnostic sting challenge; leucocyte stimulation index (SI), IL-4 production, IgE RAST, histamine release test (HRT), leukotriene release test (LRT) and basophil activation test (BAT). Intradermal venom skin testing (VST) was also performed at trial entry.

RESULTS

Only VST and HRT identified those at risk of sting anaphylaxis in the placebo group. Although IgE RAST, leucocyte SI and IL-4 production, LRT and BAT all correlated well with intradermal VSTs, they did not predict sting challenge outcome. After successful VIT, venom-induced leucocyte IL-4 production tended to fall, whereas IgE RAST increased and a natural decline in HRT reactivity was reversed. A confounding seasonal affect on laboratory results was suspected.

CONCLUSION

The HRT warrants further assessment for diagnosis of venom allergy. Uninformative performance of the commercially available LRT and BAT tests may be due to pre-incubation with IL-3. None of the tests evaluated appear to be reliable markers of successful VIT.

Impaired CD40-signalling in Langerhans' cells from murine neonatal draining lymph nodes: implications for neonatally induced cutaneous tolerance

Cutaneous tolerance to antigens may be induced in mice through application of antigen during the first few days following birth. The mechanism governing this neonatally induced tolerance remains uncertain. We employed a contact hypersensitivity model to analyse dendritic cell (DC) function and the expression of classical and non-classical lymphocyte populations within the neonate. Examination of draining lymph node DC after antigenic challenge of the skin revealed these DC to be significantly deficient in their ability to stimulate antigen-specific T cell proliferation. Co-stimulatory molecule (CD40, CD80 and CD86) expression of these cells was deficient in comparison to adult DC, and functional tests revealed these cells to possess a critical absence of CD40 signalling. A numerical analysis of classical and non-classical lymphocyte expression demonstrated that while the neonatal spleen is devoid of T cells, the lymph nodes have a normal repertoire of T, B, gammadelta and CD4+CD25+ lymphocytes but an increased expression of natural killer (NK) cells. This study indicates that functionally deficient DC are likely contributors to neonatally induced cutaneous tolerance.

Mitochondrial cytochrome c release precedes transmembrane depolarisation and caspase-3 activation during ceramide-induced apoptosis of Jurkat T cells

Whilst the role of ceramide, a second messenger of the sphingolipid family, in the initiation of receptor-mediated apoptosis is controversial, a growing body of evidence is emerging for a role of ceramide in the amplification of apoptosis via mitochondrial perturbations that culminate in the activation of execution caspases. Treatment of Jurkat T cells with the cell-permeable analog, C(2)-ceramide, resulted in the rapid onset of apoptosis as evidenced by Annexin V-FITC staining of externalised phosphatidylserine residues. Cells bearing this early apoptotic marker had a reduced mitochondrial transmembrane potential (Delta(Psi)m) that was preceded by the release of cytochrome c from mitochondria. Subsequent activation of caspase-3 provides the link between these ceramide-induced mitochondrial changes and execution caspases that ultimately result in the physical destruction of the cell. Collectively these results demonstrate that ceramide signalling results in caspase-mediated apoptosis via mitochondrial cytochrome c release and are further supportive of the role of ceramide in the amplification of apoptosis.

Mitochondrial cytochrome c release precedes transmembrane depolarisation and caspase-3 activation during ceramide-induced apoptosis of Jurkat T cells

Whilst the role of ceramide, a second messenger of the sphingolipid family, in the initiation of receptor-mediated apoptosis is controversial, a growing body of evidence is emerging for a role of ceramide in the amplification of apoptosis via mitochondrial perturbations that culminate in the activation of execution caspases. Treatment of Jurkat T cells with the cell-permeable analog, C(2)-ceramide, resulted in the rapid onset of apoptosis as evidenced by Annexin V-FITC staining of externalised phosphatidylserine residues. Cells bearing this early apoptotic marker had a reduced mitochondrial transmembrane potential (Delta(Psi)m) that was preceded by the release of cytochrome c from mitochondria. Subsequent activation of caspase-3 provides the link between these ceramide-induced mitochondrial changes and execution caspases that ultimately result in the physical destruction of the cell. Collectively these results demonstrate that ceramide signalling results in caspase-mediated apoptosis via mitochondrial cytochrome c release and are further supportive of the role of ceramide in the amplification of apoptosis.

Acquisition of immune function during the development of the Langerhans cell network in neonatal mice

The immunological function of the Langerhans cell (LC) network in neonatal skin was examined by defining the development of cutaneous immunity relative to the structure, phenotype and function of the epidermal LC network in neonatal, juvenile and adult mice. Analysis of epidermal sheets showed the presence of major histocompatibility complex (MHC) II+, multilectin receptor DEC-205- cells within the epidermis of 3-day-old mice; both cell density and DEC-205 expression increased until day 14. When visualized with antibodies directed at MHC II, the network was poorly formed in 3- and 7-day-old mice, as there was a lower cell density and poor MHC II expression on dendritic processes, compared to mice at day14. Application of a fluorescent antigen to 3-day-old mice revealed that the LC were inefficient in transporting antigen to the draining lymph node. There was an improvement at day 7 and by day 14 comparable numbers of antigen carrying cells were detected in the lymph nodes of 6-week-old mice. The reduced antigen carriage in 3- and 7-day-old mice correlated with a poor contact sensitivity response. This was not simply due to failure to present antigen, but development of immunosuppression, as transfer of T cells from adult mice that were previously treated with antigen when they were 3 days old, to adult recipients resulted in antigen specific immunosuppression. Analysis of CD80 and CD86 expression showed that LC from day 3 skin expressed CD80, but not CD86 and application of antigen through this skin was inefficient in upregulating CD86. These findings indicate that when the neonatal LC network is poorly developed it is functionally immature and antigen applied through this 'functionally immature network' results in antigen specific immunosuppression.

Cell cycle arrest of hematopoietic cell lines after treatment with ceramide is commonly associated with retinoblastoma activation

BACKGROUND

Leukaemia cells differ from their normal counterparts in that their ability to properly regulate survival, proliferation, differentiation, and apoptosis is aberrant. Understanding the molecular mechanisms controlling cell proliferation and developing therapeutic strategies to correct nonfunctional regulatory mechanisms are emerging areas of medical research. Ceramide, a metabolite of membrane sphingomyelin hydrolysis, has recently emerged as a key regulator of cellular proliferation, differentiation, and apoptosis in leukaemia cells.

METHODS

Leukaemia cell lines were treated with a biologically active analogue of ceramide, C(2)-ceramide. Cell cycle status was assessed flow cytometrically using propidium iodide. Induction of apoptosis was confirmed by annexin V staining of externalised phosphatidylserine and retinoblastoma activation was determined by Western blotting.

RESULTS

C(2)-ceramide induced activation of retinoblastoma tumour suppressor protein, G(0)/G(1) cell cycle arrest, or apoptosis in leukaemia cell lines. In addition, these effects differed depending upon cell type, thus confirming the pleiotropic nature of the ceramide signalling pathway. Most cells studied responded to exogenous C(2)-ceramide by entering growth arrest, evidently resulting from activation of retinoblastoma protein, and by displaying some degree of apoptosis.

CONCLUSIONS

Taken together, these findings suggest that signalling via ceramide has novel therapeutic applications for treatment of leukaemia.

Recombinant urate oxidase for the prophylaxis or treatment of hyperuricemia in patients With leukemia or lymphoma

PURPOSE

To improve the control of hyperuricemia in patients with leukemia or lymphoma, we tested a newly developed uricolytic agent, recombinant urate oxidase (SR29142; Rasburicase; Sanofi-Synthelabo, Inc, Paris, France), which catalyzes the oxidation of uric acid to allantoin, a highly water-soluble metabolite readily excreted by the kidneys.

PATIENTS AND METHODS

We administered Rasburicase intravenously, at 0.15 or 0.20 mg/kg, for 5 to 7 consecutive days to 131 children, adolescents, and young adults with newly diagnosed leukemia or lymphoma, who either presented with abnormally high plasma uric acid concentrations or had large tumor cell burdens. Blood levels of uric acid, creatinine, phosphorus, and potassium were measured daily. The pharmacokinetics of Rasburicase, the urinary excretion rate of allantoin, and antibodies to Rasburicase were also studied.

RESULTS

At either dosage, the recombinant enzyme produced a rapid and sharp decrease in plasma uric acid concentrations in all patients. The median level decreased by 4 hours after treatment, from 9.7 to 1 mg/dL (P =.0001), in the 65 patients who presented with hyperuricemia, and from 4.3 to 0.5 mg/dL (P =.0001) in the remaining 66 patients. Despite cytoreductive chemotherapy, plasma uric acid concentrations remained low throughout the treatment (daily median level, 0.5 mg/dL). The urinary excretion rate of allantoin increased during Rasburicase treatment, peaking on day 3. Serum phosphorus concentrations did not change significantly during the first 3 days of treatment, decreased significantly by day 4 in patients presenting with hyperuricemia (P =.0003), and fell within the normal range in all patients by 48 hours after treatment. Serum creatinine levels decreased significantly after 1 day of treatment in patients with or without hyperuricemia at diagnosis (P =.0003 and P =.02, respectively) and returned to normal range in all patients by day 6 of treatment. Toxicity was negligible, and none of the patients required dialysis. The mean plasma half-lives of the agent were 16.0 +/- 6.3 (SD) hours and 21.1 +/- 12.0 hours, respectively, in patients treated at dosages of 0.15 or 0.20 mg/kg. Seventeen of the 121 assessable patients developed antibodies to the enzyme.

CONCLUSION

Rasburicase is safe and highly effective for the prophylaxis or treatment of hyperuricemia in patients with leukemia or lymphoma.

Prevention of autoimmunity by induction of cutaneous tolerance

Autoimmune gastritis develops in 20-60% of BALB/c mice following thymectomy at 3 days after birth (3dnTx). Previously we identified the gastric H+/K+ ATPase as the causative autoantigen and mapped the immunoreactive T cell epitope to a carboxyl-terminal peptide on the gastric H+/K+ ATPase beta subunit. Here we show that autoimmune gastritis can be suppressed by immunizing 3dnTx mice through neonatal skin with the beta subunit peptide, in combination with the contact sensitizer TNCB. When spleen cells were transferred from suppressed mice to nude mice a proportion of recipient mice developed gastritis. These results indicate that pathogenic T cells were still present in the 3dnTx mice but the absence of gastritis indicates that their activity can be regulated following induction of cutaneous tolerance by immunizing through neonatal skin. We propose that cutaneous tolerance is induced through mediation of immature Langerhans cells in neonatal skin and that this tolerance prevented the autoreactivity of pathogenic T cells. This procedure will have implications for strategies to suppress autoimmunity.

Carcinogen-modified dendritic cells induce immunosuppression by incomplete T-cell activation resulting from impaired antigen uptake and reduced CD86 expression

Exposure of the skin to environmental stimuli, such as chemical or physical carcinogens, modifies the local skin environment, including depletion of epidermal Langerhans' cells (LC). Any subsequent exposure of the LC-depleted skin to antigen results in the generation of antigen-specific tolerance. In this study we evaluated the antigen-bearing cells in the draining lymph nodes by capitalizing on the fluorescent nature of the contact sensitizer, fluorescein isothiocyanate (FITC). When FITC was applied to the skin of normal mice, two distinct populations of antigen-bearing cells were identified in the draining lymph nodes. They were classified as either FITChi or FITClo on the basis of their fluorescence intensity and thus the amount of antigen they internalized. Only FITClo cells were detected in the lymph nodes draining FITC-treated murine skin that had been depleted of epidermal LC by prior treatment with the complete carcinogen 9,10-dimethyl 1,2-benzanthracene (DMBA). Functional analysis of these cells revealed that the FITChi cells, but not the FITClo cells, induced antigen-specific T-cell proliferation. Further analysis of the FITClo cells from the DMBA-treated mice demonstrated that these cells had reduced levels of CD80 expression, had substantially reduced levels of CD86 expression and performed poorly as co-stimulator cells in an anti-CD3-mediated proliferative assay. Nonetheless these cells still induced early signs of T-cell activation and interleukin-12 production. Consequently the FITClo cells migrating from the LC-depleted skin, through a combination of reduced antigen presentation and reduced co-stimulatory activity, induced a state of unresponsiveness or anergy in the responder T cells in a similar manner to that observed when antigen presentation occurs in the absence of co-stimulation. We propose that these unresponsive, or anergic cells, account for the antigen-specific tolerance observed in these experiments.

A chronology of pain and comfort in children with sickle cell disease

OBJECTIVE

To examine the patterns of children's and caregivers' descriptions of pain and the comfort measures used to relieve the pain of sickle cell disease (SCD) at home and in the hospital.

DESIGN

Qualitative and quantitative techniques were used to obtain data. Participants were seen twice, first with and then without a vaso-occlusive episode. Multiple simultaneous methodological triangulation was used to integrate the findings from ethnographic interviews and observations as well as limited quantitative findings about pain and comfort measures used.

SETTING

A Midwestern children's hospital with a regional SCD service.

PARTICIPANTS

Twenty-one African American children and adolescents with SCD, aged 6 to 15 years, and 21 family caregivers.

RESULTS

An 8-phase chronology of pain and comfort was revealed from the data about pain and comfort in children with SCD. Although this chronology was an unexpected finding, it was consistent with the original aim of the investigation. Phase 1 (baseline) represented the usual state of the child's condition, which for most was free of pain. Phase 2 or the "pre-pain" state involved no vasoocclusive pain but the child began to show prodromal signs and symptoms of painful episodes, such as yellowing of the eyes or fatigue. Phases 2 through 7 involved increasing then decreasing levels of pain, including the pain start point (phase 3), pain acceleration (phase 4), peak pain experience (phase 5), pain decrease start point (phase 6), and steady pain decline (phase 7). A trip to the emergency department usually occurred during phase 5. In phase 8 (pain resolution), the pain had decreased to a manageable level so that the child could be discharged from the hospital. As pain increased and decreased, so did the number and variety of comfort measures.

CONCLUSIONS

A chronology of the pain and comfort experiences for children and adolescents during a vasoocclusive event of SCD emerged from the descriptive data of this study. Findings need to be examined further in larger, quantitative, longitudinal studies that examine more closely the duration, intensity, and character of pain at different times during vaso-occlusive episodes as well as the comfort measures used during specific phases of the pain event.

Pancreatoduodenectomy for neonatal myofibromatosis of the pancreas

Myofibromatosis is a rare congenital disorder consisting of one or more fibrous nodules in the skin, soft tissues, bones, and internal organs. The authors report the unique case of a newborn who presented with obstructive jaundice caused by a single myofibroma in the head of the pancreas that was treated successfully by pancreatoduodenectomy on the eighth day of life.

Ketorolac-induced irreversible renal failure in sickle cell disease: a case report

Nonsteroidal anti-inflammatory drugs are often used in the management of those with acute pain secondary to sickle cell disease due to potent analgesic effects along with a lack of addictive potential, respiratory depression, and central nervous system effects, as may occur with narcotics. Caution should be observed in the use of nonsteroidal anti-inflammatory drugs in patients with compromised renal function. We present a case of a 17-year-old sickle cell disease patient with an acute painful episode and normal renal function indices who subsequently developed irreversible renal failure and a perirenal hematoma following the administration of ketorolac, despite adequate hydration. Due to its inhibitory effect on prostaglandin-mediated vasodilation, we advise caution in the use of ketorolac for the pain management of sickle cell painful episodes. We recommend following the administration guidelines for ketorolac for renal-compromised patients in those with painful episodes of sickle cell disease, and if used in this patient population, renal function must be very closely monitored.

Induction of peripheral tolerance in neonatally thymectomized mice by immunization through chemical carcinogen-altered skin

BALB/c mice thymectomized 3 days after birth (3dnTx) are prone to the development of autoimmune gastritis. As this outcome may be a consequence of altered immunoregulatory mechanisms, we set out to determine the immunological status of these mice and their capacity to acquire antigen-specific peripheral tolerance. The latter was assessed by the capacity of these mice to suppress a contact sensitivity response to 2,4,6-trinitrochlorobenzene (TNCB) following treatment of the skin by the carcinogen, DMBA. The 3dnTx mice had a reduced number of CD4(+) and CD8(+) T cells and a reduced lymphocyte proliferative response to PHA, but a normal contact sensitivity response to TNCB. After treatment of the skin with DMBA these mice failed to develop contact sensitivity to TNCB. Adoptive transfer of splenocytes from these mice to naive mice transfered antigen-specific suppression, irrespective of whether the 3dnTx mice had developed autoimmune gastritis. We conclude that despite thymectomy at day 3 and the attendant immunosuppression, the capacity of BALB/c mice to generate antigen-specific peripheral tolerance to TNCB was retained. These results suggest that precursor T cells which mediate suppression to antigens such as TNCB are present in 3dnTx mice and that these cells are likely to have developed in the thymus and exported to the periphery before 3 days after birth.

Influence of penicillin prophylaxis on antimicrobial resistance in nasopharyngeal S. pneumoniae among children with sickle cell anemia. The Ancillary Nasopharyngeal Culture Study of Prophylactic Penicillin Study II

PURPOSE

To evaluate the consequences of prolonged prophylactic penicillin use on the rates of nasopharyngeal colonization with Streptococcus pneumoniae and the prevalence of resistant pneumococcal strains in children with sickle cell anemia.

METHODS

Nasopharyngeal specimens were obtained from children with sickle cell anemia (Hb SS or Hb S beta degrees thalassemia) at 10 teaching hospitals throughout the United States. These patients were participating in a prospective, randomized, placebo-controlled trial in which they were prescribed prophylactic penicillin before their fifth birthday and were randomized to prophylactic penicillin or placebo after their fifth birthday (PROPS II). The specimens were cultured for S. pneumoniae, and isolates were analyzed for antimicrobial susceptibility to nine commonly prescribed antimicrobial agents.

RESULTS

Of the 226 patients observed, an average of 8.4 specimens were collected per patient. From 1,896 individual culture specimens, 5.5% of the specimens were positive for S. pneumoniae; 27% of patients had at least one positive culture. Nine percent of the study patients had at least one isolate of penicillin intermediate or resistant pneumococci. There was no significant difference in the percent of positive cultures for S. pneumoniae in those patients given penicillin prophylaxis after 5 years of age (4.1%) compared with those patients given placebo after 5 years of age (6.4%). Likewise, there was no significant difference (p = 0.298) in the percent of patients with at least one positive culture for S. pneumoniae in the group given prophylactic penicillin after 5 years of age (21.8%) compared with the group given placebo after 5 years of age (28.3%). There was no difference between the penicillin and placebo groups in the proportion of patients with penicillin intermediate or resistant pneumococci, but there was a trend toward increased carriage of multiply drug-resistant pneumococci in children > 5 years of age receiving prophylactic penicillin compared to children > 5 years of age receiving placebo. The increased colonization rate with multiply drug-resistant organisms of children > 5 years of age receiving penicillin prophylaxis is not statistically significant.

CONCLUSIONS

The potential for continued penicillin prophylaxis to contribute to the development of multiply resistant pneumococci should be considered before continuing penicillin prophylaxis in children with sickle cell anemia who are older than 5 years of age. Added to the published data from PROPS II, which demonstrated no apparent advantage to continue prophylaxis, the data support the conclusion that, for children with no history of invasive pneumococcal disease, consideration should be given to discontinue prophylactic penicillin after their fifth birthday.

Chemical carcinogens and antigens contribute to cutaneous tumor promotion by depleting epidermal Langerhans cells

Epidermal Langerhans cells (LC) are an integral component of the skin immune system as they initiate immune responses to a variety of antigens, including tumor antigens. When skin is exposed to carcinogenic doses of ultraviolet-B irradiation, chemical carcinogens or tumor promoters there is a significant reduction of LC density. This causes the skin to be immunocompromised and provides an opportunity for aberrant cells to escape immune detection and develop into tumors. Consequently LC depletion is a key event associated with the pathogenesis of skin cancer. We propose that LC depletion contributes to tumor promotion and therefore any agents that reduce LC number, e.g. the contact sensitizing antigen 2,4,6-trinitrochlorobenzene (TNCB), may also contribute to tumor promotion. This proposal was evaluated in cutaneous carcinogenesis by treating mouse skin with a tumor initiating dose of the carcinogen 7,12-dimethylbenz[a]anthracene (DMBA) followed by a tumor promoter. The initiating dose of DMBA did not cause LC depletion or tumor development. However, if the DMBA-treated skin was then exposed to a concentration of TNCB that caused LC depletion, skin tumors developed. This is analogous to the classical initiator/promoter system with an LC-depleting dose of TNCB contributing to tumor promotion. Further, this promotion effect was independent of the commencement time of the promoter application, as 2% TNCB applied either 1 or 12 weeks after DMBA initiation induced tumor development. Analysis of the association of LC depletion with immunosuppression and tumor promotion, showed that these events were linked, irrespective of the agent that caused the depletion. It is therefore concluded that LC depletion and local immunosuppression are important aspects of tumor promotion in cutaneous carcinogenesis and non-carcinogenic agents may have tumor promoter activities.

Down-regulation of an established immune response via chemical carcinogen or UVB-altered skin

The ability to produce antigen-specific down-regulation of an established immune response was investigated in 2,4,6-trinitrochlorobenzene (TNCB)-immune mice by delivery of antigen through chemical carcinogen- or ultraviolet B (UVB)-treated skin. When TNCB-immune mice were treated on the dorsal trunk skin with 7,12-dimethylbenz(a)anthracene (DMBA) followed by TNCB there was an antigen-specific reduction in both contact sensitivity and antibody production. Further, immune mice that received spleen cells from naive syngeneic donors treated with DMBA followed by TNCB also exhibited a reduction in both contact sensitivity and antibody production. In contrast, mice treated with UVB irradiation followed by TNCB had a reduction in contact sensitivity but not antibody production. These results provide evidence that an ongoing immune response can be manipulated by immunization through a modified skin immune system. This may provide a beneficial approach for the treatment of autoimmune disease.

Failure of carcinogen-altered dendritic cells to initiate T cell proliferation is associated with reduced IL-1 beta secretion

The activation of T cells through presentation of antigen by dendritic cells (DC) relies on many factors, including the correct balance of cytokines in the immediate microenvironment. Antigen presentation by DC migrating from carcinogen-treated skin is impaired as evidenced by the failure of antigen-pulsed DC to initiate specific T cell proliferation. To elucidate mechanism(s) of DC dysfunction, DC migrating from carcinogen-treated skin were collected, pulsed with OVA, and cultured with antigen-specific autologous lymphocytes. Supernatants were assayed for the costimulatory cytokine IL-1 beta which influences the outcome of DC:T cell interactions. The dendritic cells migrating from carcinogen-treated skin that failed to induce T cell proliferation were unable to produce IL-1 beta. This may account for the abrogation of DC function following exposure to chemical carcinogens and provides an explanation for the inability of DC to induce a protective immune response to carcinogen-induced tumours.

P-glycoprotein mediated multidrug resistance and its implications for pathology

The discovery of P-glycoprotein has revealed a fundamental mechanism by which cancer cells evade chemotherapy and this principle has proven relevant to general cellular defence mechanisms in normal physiology. To date this knowledge has promised to improve current cancer chemotherapy through the manipulation of drug combinations according to the P-glycoprotein status of the tumor. Furthermore, the discovery of inhibitors of the protein may provide new therapeutic tools in the treatment of multidrug resistant neoplasia, provided the benefits are deemed greater than the potential detrimental side effects. When looking towards future therapies, however, we must also consider additional mechanisms which undoubtedly contribute to clinical drug resistance. Complete elucidation of this complex cellular defence network will hopefully translate into therapeutic opportunities to circumvent all mechanisms of multidrug resistance, thus positively impacting on patient survival.

Serotype-specific immunoglobulin G antibody responses to pneumococcal polysaccharide vaccine in children with sickle cell anemia: effects of continued penicillin prophylaxis

OBJECTIVES

(1) To determine serotype-specific IgG antibody responses to reimmunization with pneumococcal polysaccharide vaccine at age 5 years in children with sickle cell anemia and (2) to determine whether continued penicillin prophylaxis had any adverse effects on these responses.

STUDY DESIGN

Children with sickle cell anemia, who had been treated with prophylactic penicillin for at least 2 years before their fifth birthday, were randomly selected at age 5 years to continue penicillin prophylaxis or to receive placebo treatment. These children had been immunized once or twice in early childhood with pneumococcal polysaccharide vaccine and were reimmunized at the time of randomization.

RESULTS

Serotype-specific IgG antibody responses to reimmunization varied according to pneumococcal serotype but in general were mediocre or poor; the poorest response was to serotype 6B. The antibody responses were similar in subjects with continued penicillin prophylaxis or placebo treatment, and in subjects who received one or two pneumococcal vaccinations before reimmunization. The occurrence of pneumococcal bacteremia was associated with low IgG antibody concentrations to the infecting serotype.

CONCLUSIONS

Reimmunization of children with sickle cell anemia who received pneumococcal polysaccharide vaccine at age 5 years induces limited production of serotype-specific IgG antibodies, regardless of previous pneumococcal vaccine history. Continued penicillin prophylaxis does not interfere with serotype-specific IgG antibody responses to reimmunization.

Chemical carcinogens and antigens induce immune suppression via Langerhans' cell depletion

The ability of the chemical carcinogen dimethylbenz(a)anthracene (DMBA) to deplete Langerhans' cells (LC) from murine skin is crucial to the development of antigen-specific suppression. This depletion is a consequence of the LC recognizing the DMBA as antigenic and migrating to the draining lymph nodes to attempt to elicit T-cell activation. This depletion also occurred following exposure to high doses of the contact sensitizers 2,4-dinitrofluorobenzene (DNFB), 2,4,6-trinitrochlorobenzene (TNCB) and fluorescein isothiocyanate (FITC). However, LC depletion was not significant at lower doses, even though these doses were sufficient to induce strong contact sensitivity responses. Application of the contact sensitizer, DNFB, through skin depleted of LC (by pretreatment with either the carcinogen DMBA or the antigen TNCB) failed to induce contact sensitivity. This immune non-responsiveness was antigen specific, and could be transferred by spleen cells to naive mice, which were unable to respond to DNFB. Mouse skin treated with doses of TNCB, that did not cause LC depletion but still induced a normal contact hypersensitivity, retained its ability to initiate a normal immune response to DNFB. Together these findings demonstrate that carcinogens share some properties with antigens as they both cause LC depletion and interact with the immune system. Furthermore, it is this LC depletion, rather than carcinogen treatment, that is a critical factor which leaves the skin immunologically compromised and favours the induction of antigen-specific suppression.

Discontinuing penicillin prophylaxis in children with sickle cell anemia. Prophylactic Penicillin Study II

OBJECTIVE

To evaluate the consequences of discontinuing penicillin prophylaxis at 5 years of age in children with sickle cell anemia who had received prophylactic penicillin for much of their lives.

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Eighteen teaching hospitals throughout the United States.

PATIENTS

Children with sickle cell anemia (hemoglobin SS or hemoglobin S beta 0-thalassemia) who had received prophylactic penicillin therapy for at least 2 years immediately before their fifth birthday and had received the 23-valent pneumococcal vaccine between 2 and 3 years of age and again at the time of randomization. Of 599 potential candidates, 400 were randomly selected and followed for an average of 3.2 years.

INTERVENTIONS

After randomization, patients received the study medication twice daily--either penicillin V potassium, 250 mg, or an identical placebo tablet. Patients were either seen in the clinic or contacted every 3 months thereafter for an interval history and dispensing of the study drug. A physical examination was scheduled every 6 months.

MAIN OUTCOME MEASURES

The primary end point was a comparison of the incidence of bacteremia or meningitis caused by Streptococcus pneumoniae in children continuing penicillin prophylaxis versus those receiving the placebo.

RESULTS

Six children had a systemic infection caused by S. pneumoniae, four in the placebo group (2.0%; 95% confidence interval 0.5%, 5.0%) and two in the continued penicillin prophylaxis group (1.0%; 95% confidence interval 0.1%, 3.6%) with a relative risk of 0.5 (95% confidence interval 0.1, 2.7). All invasive isolates were either serotype 6(A or B) or serotype 23F. Four of the isolates were penicillin susceptible, and two (one from each treatment group) were penicillin and multiply antibiotic resistant. Adverse effects of the study drug were reported for three patients (nausea, vomiting, or both), one of whom was in the placebo group.

CONCLUSION

Children with sickle cell anemia who have not had a prior severe pneumococcal infection or a splenectomy and are receiving comprehensive care may safely stop prophylactic penicillin therapy at 5 years of age. Parents must be aggressively counseled to seek medical attention for all febrile events in children with sickle cell anemia.

Processing of complex antigens and simple hapten-like molecules by epidermal Langerhans cells

Langerhans cells (LCs) are antigen-presenting cells of the skin that trap small contact-sensitizing molecules and induce cutaneous hypersensitivity. LCs can present larger molecules but the mechanisms of processing have required investigation. A system combining in vitro culture of antigen with epidermal cells in the presence of inhibitors, followed by fixation and transfer of these antigen/drug-treated epidermal cells to naive mice, was developed to investigate the steps of antigen processing. Langerhans cells undertake similar, but not identical, pathways for the processing of simple and complex molecules. Complex molecules such as trinitrophenyl conjugated to ovalbumin (TNP-OVA) were internalized and modification required a chloroquine-sensitive proteolysis step and a cycloheximide-sensitive protein synthesis step. This modified product was actively recycled to the cell membrane as presentation was inhibited by blocking receptor translocation with either monensin or cytochalasin B. Small contact sensitizers such as trinitrophenyl did not undergo modification but required internalization and presentation was also inhibited by blocking receptor translocation.

Abrogation of afferent lymph dendritic cell function after cutaneously applied chemical carcinogens

Chemical carcinogens reduce cutaneous immunity, an event accompanied by alterations to the number and morphology of the resident epidermal Langerhans cell (LC) population. This study aimed to examine the functional capacity of LC and other dendritic cells (DC) that are migrating from carcinogen-treated skin via afferent lymphatic vessels. Generation and subsequent cannulation of prefemoral pseudoafferent lymphatic vessels in sheep allowed continuous collection of DC migrating from a defined area of carcinogen-treated skin. The ability of metrizamide-enriched afferent lymph DC to present antigen to autologous primed peripheral blood lymphocytes was used as an indicator of DC function. Topical application of the complete carcinogens 7,12-dimethylbenz[a]anthracene and benzo[a]pyrene abrogated the stimulatory capacity of migrating DC for periods of 8 weeks and 5 weeks, respectively, whereas the tumor promoter 12-O-tetradecanoylphorbol-13-acetate reduced DC function for less than 1 week. These findings favor tumor development in carcinogen-treated skin being enhanced due to impairment of DC immunological surveillance.

Functional asplenia in hemoglobin SC disease

The incidence of functional asplenia in sickle-hemoglobin C (SC) disease has not been defined, and the use of prophylactic penicillin to prevent life-threatening septicemia in this disorder is controversial. The percentage of red blood cells with pits (pit count) is a reliable assay of splenic function in other disorders but has not been validated in hemoglobin SC disease. To address these issues, we conducted a prospective, multicenter study of splenic function in persons with hemoglobin SC disease. Baseline clinical data were recorded, and red blood cell pit counts were performed on 201 subjects, aged 6 months to 90 years, with hemoglobin SC; 43 subjects underwent radionuclide liver-spleen scanning. Pit counts greater than 20% were associated with functional asplenia as assessed by liver-spleen scan, whereas pit counts less than 20% were found in subjects with preserved splenic function. Pit counts greater than 20% were present in 0 of 59 subjects (0%) less than 4 years of age, in 19 of 86 subjects (22%) 4 to 12 years of age, and in 25 of 56 subjects (45%) greater than 12 years of age. Other subjects with hemoglobin SC, who had previously undergone surgical splenectomy, had higher pit counts (59.7% +/- 9.5%) than splenectomized subjects without hemoglobinopathy (38.5% +/- 8.8%) or with sickle cell anemia (20.5% +/- 1.9%; P < .001). Two subjects with hemoglobin SC disease (not splenectomized), ages 14 and 15 years, with pit counts of 40.3% and 41.7% died from pneumococcal septicemia. These data indicate that functional asplenia occurs in many patients with hemoglobin SC disease, but its development is usually delayed until after 4 years of age. The pit count is a reliable measure of splenic function in hemoglobin SC disease, but values indicative of functional asplenia (> 20% in our laboratory) are higher than in other disorders. The routine administration of prophylactic penicillin to infants and young children with hemoglobin SC disease may not be necessary.

Murine retrovirus induces defects in the function of dendritic cells at early stages of infection

The infection and function of lymph node dendritic cells (DC) were analyzed at different time points of Rauscher leukemia virus infection in mice (3, 7, 14, and 21 days). Infection of DC was apparent after 3 days and significant infection (1-10% of the DC population) was documented after 7 days. DC from infected mice as early as 3 days postinfection had a reduced ability to stimulate allogeneic normal T cells in the mixed lymphocyte reaction. T cells did become infected during the coculture but block of cross-infection of T cells by zidovudine did not abolish the inhibitory effect. Other DC-dependent responses were also reduced on infection including DC-stimulated responses to influenza virus. ConA and PMA induced an increase in [Ca2+]i level in DC from control mice. A low baseline level of [Ca2+]i in DC from infected mice and reduced calcium mobilization upon ConA stimulation was found at all periods of infection. Ultraviolet-inactivated Rauscher leukemia virus failed to provoke significant changes in DC function in vivo. Six or 7 days after RLV infection DC expressed lower levels of Iad but not H2Dd molecules in parallel with lower expression of some adhesion molecules (CD18, CD54, CD44). No differences in expression of B7 surface antigen between control and infected mice were obtained. We did not find any evidence for the induction of apoptosis of naive syngeneic or allogeneic T cells by infected dendritic cells. The changes in DC function may have implications for the pathogenesis of retroviral infections including HIV infection.

Fatal pneumococcal septicemia in hemoglobin SC disease

We retrospectively examined the medical and autopsy records of seven previously unpublished cases of fatal pneumococcal septicemia in children with hemoglobin SC disease. The earliest death occurred in a 1-year-old child who had congenital heart disease with cyanosis; the other children were aged 3 1/2 to 15 years. Only one child had received pneumococcal vaccine or prophylactic penicillin therapy. All seven children had an acute febrile illness and rapid clinical deterioration despite parenterally administered antibiotic therapy and intensive medical support. Erythrocyte pit counts in two patients were 40.3% and 41.7%, respectively (normal, < or = 3.6%). Autopsy data from five cases showed marked splenic congestion without infarction in five, splenomegaly in four, and bilateral adrenal hemorrhage in three. These cases illustrate that functional asplenia predisposes some children with hemoglobin SC disease to the development of fatal septicemia after the age of 3 years. We conclude that pneumococcal vaccine should be administered to all children with hemoglobin SC disease and that acute febrile illnesses should be investigated promptly for the possibility of septicemia. The routine use of prophylactic penicillin therapy in infants and children with hemoglobin SC disease remains controversial.

Retrovirus-induced immunosuppression via blocking of dendritic cell migration and down-regulation of adhesion molecules

Dendritic cells (DC) within tissues may acquire and process antigens, carry them into lymph nodes and cluster and activate T cells. The ability of DC to acquire antigen and to migrate to lymph nodes was estimated during murine retroviral infection caused by Rauscher leukaemia virus (RLV). A novel mechanism of inducing immunodeficiency has now been identified. In mice infected with RLV, DC failed to migrate into lymph nodes following exposure of the skin to the contact sensitizer, fluorescein isothiocyanate. RLV infection of a proportion of DC both in skin and lymph nodes, shown by semi-quantitative polymerase chain reaction (PCR) and down-regulation of expression of adhesion molecules (CD54 and CD44) on the surface of Langerhans' cells, may contribute to the described phenomenon. A failure of DC migration could be an important immunosuppressive mechanism of RLV infection in mice and we speculate on a similar role for DC in human immunodeficiency virus-1 (HIV-1) infection in humans.

Langerhans cell migration patterns from sheep skin following topical application of carcinogens

Application of tumour promoters or complete chemical carcinogens to skin alters the density and/or morphology of epidermal Langerhans cells (LC). To examine the hypothesis that these chemical carcinogens alter LC migration kinetics from the epidermis, pseudoafferent lymphatic vessels draining defined areas of carcinogen treated sheep skin were cannulated and the number of LC migrating enumerated using indirect immunofluorescence and flow cytometry. The complete carcinogen benzo[a]pyrene (BP) and the tumour promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) caused an immediate two to four-fold increase in the rate of LC migration, while the tumour initiator urethane did not alter LC migration. The antigenicity of the carcinogens utilized was assessed in contact hypersensitivity experiments in mice. BP and TPA were mildly antigenic whereas urethane failed to initiate a contact hypersensitivity response in sensitized mice. It is concluded that the initial increase in LC migration from skin following the application of the tumour promoter TPA and the complete carcinogen BP is partly due to LC recognizing these carcinogens as antigens.

Langerhans cell alterations in cutaneous carcinogenesis

Analysis of the early stages of experimental skin cancer in mice has demonstrated that complete chemical carcinogens (e.g. DMBA or benzo(a)pyrene) and tumour promoters (e.g. TPA) but not tumour initiators (e.g. urethane) deplete or functionally alter epidermal Langerhans cells (LC). These changes result in altered local immunity as antigen presentation through LC depleted skin results in either immune tolerance due to the generation of suppressor T cells or anergy. Parallel studies in sheep have shown that, following the application of DMBA, depletion of LC is due to increased migration of these cells from the skin whereas tumour initiators did not alter LC migration. Likewise benzo(a)pyrene did not trigger enhanced LC migration from the epidermis. Experiments in mice suggest that part of this increased migration after the application of DMBA is due to the carcinogen being handled as an antigen by the epidermal LC. However, this fails to explain the prolonged migration which follows. The implication of these studies is that early in carcinogenesis, altered immune function occurs as a result of LC depletion/modification, allowing aberrant cells to proliferate in the absence of immune destruction.

Control of epidemic group A meningococcal disease in Auckland

AIM

To study group A meningococcal vaccine delivery to infants less than 2 years of age in Auckland in 1987 to control epidemic disease.

METHODS

Mechanisms of vaccine delivery and its facilitation are described. A detailed audit of delivery of vaccine to children less than two years using signed consent forms determined delivery source. This was the age group at highest risk, and poorly covered by routine childhood vaccines. Primary health care source of children presenting with disease was determined by telephone.

RESULTS

The epidemic of group A meningococcal disease in the winters of 1985 and 1986 abated most likely due to the vaccination of high risk children (3 months-13 years) in 1987. 90% of the target population were vaccinated. In south Auckland the majority (92%) of vaccine doses for children less than two years of age was delivered by the Plunket Society with Department of Health backing aided by community health workers. By contrast delivery by, general practitioners was greater in north-west and central Auckland (approximately 25%, of dose 1), especially after the publicity over possible side effects (approximately 50% of dose 2). Coverage for dose 1 of children < 2 years was similar (89%) in south Auckland. Of children presenting with meningococcal disease 1 in 4 did not have an identifiable general practitioner.

CONCLUSIONS

Vaccines to prevent serious paediatric illness are known to be highly cost effective. The best method of delivery of vaccinations may vary from area to area. Major community involvement including community health workers for the Maori and Pacific Island communities may have facilitated the dissemination of information in this campaign.

X;6 translocation in a child with congenital acute lymphocytic leukemia

A case of congenital acute lymphoblastic leukemia (ALL) displayed an X;6 translocation. This is the third reported case of ALL with an X;6 translocation. In addition, two of the three ALL cases occurred during infancy, at ages 2 months and newborn, and both translocations involved the band q15-16 region of chromosome 6. Anomalies of the long arm of chromosome 6, mainly interstitial and terminal deletions, have been reported as a recurrent karyotypic event in a significant number of ALL cases. The molecular basis and propensity of an X;6 rearrangement in this case of congenital ALL is unclear and merits further investigation. The similarities in this case and the other infant ALL case cited suggest that an X;6 rearrangement with a breakpoint in bands q15-16 of chromosome 6 is characteristic of a form of congenital ALL.

Identification of a novel latency-specific splice donor signal within the herpes simplex virus type 1 2.0-kilobase latency-associated transcript (LAT): translation inhibition of LAT open reading frames by the intron within the 2.0-kilobase LAT

Herpes simplex virus type 1 establishes latent infection in trigeminal ganglia of mice infected via the eye. A family of three colinear viral transcripts (LATs), 2.0, 1.5, and 1.45 kb, is present in latently infected ganglia. To characterize these LATs, lambda gt10 cDNA libraries were constructed with RNAs isolated from the trigeminal ganglia of latently infected mice. A series of recombinant bacteriophage were isolated containing cDNA inserts covering 1.7 kb of the 2.0-kb LAT. Splice junctions of the smaller LATs and the 3' end of the 2.0-kb LAT were identified by sequence analysis of RNA polymerase chain reaction products. No splice acceptor site, which does not support the hypotheses that the 2.0-kb LAT is an intron. However, the data are consistent with the possibility of a short leader sequence or multiple LAT transcription start sites. To generate the smaller 1.5- and 1.45-kb LATs, there is a 559-nucleotide intron spliced from the 2.0-kb LAT in strain F and a 556-nucleotide intron in strain 17+. The nucleotide sequences at the 5' and 3' ends of these introns are characteristic of spliced transcripts from eukaryotic protein-encoding genes, with one significant difference; i.e., the 5' end of the LAT intron is GC instead of the consensus sequence GT. This splice donor sequence is conserved in herpes simplex virus type 1 strains F, 17+, and KOS. Processing of the 2.0-kb LAT to form the spliced LATs preserves two open reading frames (ORFs) at the 3' end of the LATs; no new ORFs are created. Splicing of the LATs positions a 276-nucleotide leader sequence close to these ORFs and removes an intron that inhibits their translation in vitro. The novel 5' structure of the intron within the 2.0-kb LAT may be part of a control mechanism for transcription processing that results in splicing of the LATs only in sensory neurons during latent infection and reactivation but not during the viral replication cycle.

Clonal loss of INT-2 alleles in sporadic and familial pancreatic endocrine tumours

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Diffuse bony metastases at presentation in a child with glioblastoma multiforme. A case report

At initial diagnosis, an 11-year-old girl with glioblastoma multiforme (GBM) presented with diffuse osteoblastic metastases. Primary brain tumors rarely metastasize outside of the central nervous system (CNS) without prior neurosurgery. Extracranial spread at diagnosis has been previously documented in just two adults. Extracranial metastasis of a childhood glioma without prior neurosurgery at any time during the course of the disease is exceedingly rare. Spread to bone by gliomas is also infrequent, and when they occur, bony metastases are usually isolated to one or two sites in any given patient. The widespread osseous metastases in our patient have been reported in three prior cases of high-grade gliomas. This child's GBM likely reflects a highly aggressive variant with the potential to spread outside the CNS and with a predilection for bone. Oncologists should be aware that GBM may present in this fashion during childhood.