Monitoring the spread of myxoma virus in rabbit Oryctolagus cuniculus populations on the southern tablelands of New South Wales,Australia. III. Release,persistence and rate of spread of an identifiable strain of myxoma virus

An identifiable strain of myxoma virus was introduced into four local populations of wild rabbits Oryctolagus cuniculus on the southern tablelands of New South Wales (NSW) and its spread in the presence of other field strains was monitored for 6 months. The main vector in this region was considered to be the European rabbit flea Spilopsyllis cuniculi. Each population of rabbits was of a high density and living in groups of warrens covering areas from 59 to 87 hectares. Rabbits occupying centrally located warrens were inoculated with the virus in late September or early October (spring) and the subsequent appearance of myxomatosis across the sites monitored by trapping, shooting and visual observations. Samples, taken from rabbits with myxomatosis, were examined by polymerase chain reaction (PCR) that allowed identification of the introduced strain. On all four sites the introduced virus spread from the inoculated rabbits in the centrally located warrens to rabbits in surrounding warrens. On Sites 1 and 3, this spread continued across the entire site persisting for at least 118 and 174 days respectively. On Sites 2 and 4, the virus was detected for 78 and 62 days respectively and the subsequent inability to detect the introduced virus correlated with the appearance of an unrelated field strain. Using three different methods of calculation, rates of spread ranged from 3.7 to 17.8 m d(-1).     

Monitoring the spread of myxoma virus in rabbit Oryctolagus cuniculus populations on the southern tablelands of New South Wales,Australia. I. Natural occurrence of myxomatosis

A survey of rabbit populations in the southern tablelands of New South Wales, Australia, was carried out to establish the pattern of occurrence of myxomatosis in preparation for a deliberate release of myxoma virus. Myxomatosis was first detected in December and cases were found on most sites through to May. The serological profiles of rabbit populations suggested that their susceptibility to myxoma virus was generally low in winter and highest in spring and summer reflecting the presence of increasing numbers of susceptible young rabbits. This was consistent with the pattern of rabbit breeding, as determined from the distribution of births and reproductive activity in females and males, which occurred maximally in spring and early summer. The serology and age structure of rabbit populations on sites suggested that some rabbit populations can escape an annual myxomatosis epizootic. Although fleas were present on rabbits throughout the year and therefore not considered to be a limiting factor in the spread of myxomatosis, their numbers peaked at times coincident with peak rabbit breeding. It was concluded that mid to late spring was an optimal time for a deliberate release.     

Beta-platelet-derived growth factor receptor mediates motility and growth of Ewing's sarcoma cells

The Ewing's sarcoma family of tumors (ESFT) contain a translocation, t(11;22), which results in the novel oncogenic fusion protein EWS/FLI1. Platelet-derived growth factors (PDGF) and their receptors (PDGFR) are involved in the induction and proliferation of numerous solid tumors and are the potential candidates for novel targeted antitumor therapy. Since a relation was reported between PDGF-C and EWS/FLI1, we sought to characterize the PDGF signaling pathway in ESFT. Eight out of nine ESFT cell lines were found to express significant levels of beta-PDGFR. Interestingly, none of the tested cell lines expressed alpha-PDGFR, which is the receptor isotype required for PDGF-C binding. By immunohistochemical staining 47 of 52 (90.4%) archival tumor samples from patients with ESFT were positive for beta-PDGFR. ESFT cell lines were treated with PDGF-AA or PDGF-BB ligands to evaluate downstream signaling. Autophosphorylation of beta-PDGFR and tyrosine phosphorylation of PLC-gamma, PI3Kp85 and Shc were detected only in PDGF-BB-stimulated cells that express beta-PDGFR. Receptor function was further evaluated using chemotaxis assays that showed TC-32 cell migration towards PDGF-BB. A specific PDGFR kinase inhibitor AG1295 blocked beta-PDGFR activation, downstream signaling, growth in cell culture and chemotaxis of TC-32 cells. AG1295 also delayed tumor formation and prolonged survival in an ESFT animal model. We conclude that ESFT express beta-PDGFR and that this is a functional and potentially crucial signaling pathway. Therefore, beta-PDGFRs may provide a novel therapeutic target in ESFT that can be utilized to design better treatment modalities.     

Tumor expression of 4-1BB ligand sustains tumor lytic T cells

Inadequate costimulation by solid tumors is generally believed to induce immune tolerance during primary tumor growth. We looked for tumor-specific immunity vs. tolerance in patients with Ewing's sarcoma. Circulating T cells from patients with progressively growing Ewing's tumors displayed MHC restricted tumor-induced proliferation and robust tumor lysis. Tumor-reactive T cells reside within the memory CD3+CD8+ subset and are CD28-/4-1BB+. Autologous Ewing's tumors expressed 4-1BBL, and tumor-induced T cell proliferation and activation required costimulation by 4-1BBL. Stimulation of PBL with anti-CD3/4-1BBL, but not anti-CD3/anti-CD28 induced tumor lytic effectors. Similarly, in a xenograft model, anti-CD3/4-1BBL expanded T cells controlled primary growth and prevented metastasis of autologous tumors while nonactivated and anti-CD3/anti-CD28 activated CD8+ cells did not. These results question prevailing models of tumor induced tolerance accompanying progressive tumor growth; rather, we show coexistence of progressive tumor growth and anti-tumor immunity, with costimulation provided by the tumor itself. They further demonstrate a potential new therapeutic role for 4-1BBL mediated costimulation in expanding tumor reactive CTLs for use in the adoptive immunotherapy of cancer.     

Fractures in pediatric Ewing sarcoma

PURPOSE: To determine the incidence, timing, and clinical significance of long-bone fractures in children with Ewing sarcoma family of tumors (ESFT). PATIENTS AND METHODS: We retrospectively reviewed 93 consecutive cases of ESFT of the long bones seen at a single institution over the course of a 37-year period. RESULTS: Fracture occurred in 14 (15%) of 93 patients with long-bone ESFT, most commonly in the femur. Approximately 30% of patients with tumors of the femur had fractures at some point in the course of their disease. The incidence of fracture was highest among patients with tumors of the proximal third of the femur (50%); these fractures were usually present at the time of initial diagnosis. Nine (64%) of the 14 fractures occurred after the start of radiotherapy, and three of these were associated with either local recurrence or second malignancy. CONCLUSIONS: Patients with femoral ESFT are at high-risk for fracture. If fractures occur after the completion of therapy, recurrence or second malignancy should be suspected.     

Temporal bone histopathological and quantitative analysis of mitochondrial DNA in MELAS

OBJECTIVES/HYPOTHESIS: Although hearing loss is common in MELAS (syndrome of mitochondrial encephalopathy, lactic acidosis and stroke-like episodes), the histopathology of the temporal bone has not been reported. The majority of cases of MELAS are linked to a mitochondrial DNA (mtDNA) mutation at nucleotide 3243. In MELAS, normal mtDNA and mutant mtDNA coexist in a heteroplasmic manner. The purpose of the study was to report the otopathological findings from two patients with MELAS and quantitative mtDNA analysis in the inner ear of one of these patients. STUDY DESIGN: Basic scientific histopathological examination and quantitative mtDNA analysis of the temporal bone. METHODS: Temporal bones were embedded in celloidin and sectioned for light microscopic study. Graphic reconstruction of the cochlea was performed using the method described by Schuknecht. For quantitative mtDNA analysis, total DNA from the membranous part of the inner ear was collected, amplified by polymerase chain reaction, and digested with the restriction enzyme. The percentage of mutant/total mtDNA was measured by the ratio of fluorescence intensity. RESULTS: Histopathological examination revealed severe degeneration of the stria vascularis and degenerative change of spiral ganglion cells in both patients. The quantitative DNA studies showed that the proportion of mutant to wild-type mtDNA was similar in both histologically affected and histologically unaffected tissues within the inner ear. CONCLUSION: Dysfunction of the stria vascularis and spiral ganglion cells causes sensorineural hearing loss in MELAS.     

The use of B vitamin supplements and peripheral arterial disease risk in men are inversely related

Peripheral arterial disease (PAD) causes morbidity and is associated with mortality. B vitamin intake has been inversely associated with coronary heart disease, but their effects on PAD are not known. We examined prospectively the relationships between dietary folate, vitamin B-6 and B-12 and PAD risk in 51529 male U.S. health professionals, aged 40 to 75 y, who answered a detailed 131-item questionnaire to assess diet and vitamin supplement use. The study population consisted of 46036 men free of PAD, cardiovascular disease and diabetes at baseline followed for 12 y during which we documented 308 incident PAD cases. For every 400 microg/d increment of folate intake, the multivariate adjusted PAD risk decreased by 21% [relative risk (RR) = 0.79, 95% CI 0.64-0.96]. Men in the top category of folate intake (median = 840 micro g) were at 33% lower risk of PAD than men in the bottom category (median = 244 microg) (RR = 0.67, 95% CI 0.45-0.96, P-value, test for trend = 0.03) after multivariate adjustment. There were weak inverse associations between intake of vitamin B-6 and PAD risk (RR = 0.70, 95% CI 0.48-1.02, P-value, test for trend = 0.06) and B-12 (RR = 0.77, 95% CI 0.54-1.11, P-value, test for trend = 0.12). These results suggest that higher consumption of folate may contribute to the prevention of PAD.     

Clinical profile of HIV infection

OBJECTIVE: To study the clinical profile of human immunodeficiency virus (HIV) infection in children. DESIGN: Prospective. SETTING: HIV clinic at a pediatric tertiary care center in an urban metropolis. METHODS: From August 1994 onwards, 285 HIV positive children were referred to the HIV clinic. These included those intramural deliveries born to HIV positive mothers, those referred from other centers with a positive HIV ELISA (enzyme-linked immunosorbent assay) test and those screened routinely at our center in view of transfusion dependence and found to be HIV positive. After informed consent from either parent, the HIV status of all referred patients was retested by ELISA. RESULTS: Two hundred and thirteen (74.73%) patients were below the age of five years. Vertical transmission as the route of infection was documented in 247 (86.66%), 33 (11.57%) were infected through blood and in 5 (1.75%), the mode of transmission could not be ascertained. The clinical features noted were protein energy malnutrition in 127 (44.56%), pulmonary and extrapulmonary tuberculosis in 84 (29.47%), hepatosplenomegaly in 82 (28.77%), persistent generalized lymphadenopathy in 67 (23.50%), skin lesions in 63 (22.10%), chronic diarrhea in 43 (15.08%), oral thrush in 42 (14.73%), pyrexia of unknown origin in 36 (12.63%), chronic lung disease in 32 (11.22%), chronic hypertrophic parotitis in 27 (9.47%), chronic ottorrhea in 26 (9.12%), recurrent lower respiratory tract infection in 24 (8.42%), neurological manifestations of non-tuberculous origin in 13 (4.56%) and Pneumocystis carinii pneumonia in 11(3.88%). Forty-eight (16.84%) were asymptomatic, 30 (10.52%) died of AIDS during the study period and 39 (13.68%) have been lost to follow up. CONCLUSION: Vertical transmission was the commonest mode of infection. Perinatally infected children become symptomatic by five years of age. Protein energy malnutrition, hepatosplenomegaly and persistent generalized lymphadenopathy were common presenting features. Tuberculosis was the major co-infection. Chronic hypertrophic parotitis and chronic lung disease were distinguishing features of this study. Encephalopathy was associated with poor outcome.     

Validation of outcomes survey for adults with chronic suppurative otitis media

Currently, there is no valid, disease-specific outcomes measure to evaluate health impact and treatment effectiveness for patients with chronic suppurative otitis media (CSOM). The Chronic Ear Survey (CES) is a new, disease-specific outcomes measure for CSOM that was administered in a prospective manner to 91 patients with CSOM. It was then validated according to established criteria for reliability, validity, and sensitivity to clinical change by correlation with objective data and self-assessment questionnaires such as the Hearing Handicap Inventory for Adults (HHIA) and the generic 36-Item Short-Form Health Survey (SF-36). Significant correlations between subscale scores of the CES and audiometric data and between subscale scores of the HHIA and SF-36 were found. The standardized response mean for the CES total score was 0.42, indicating moderate sensitivity to clinical change. Overall, results demonstrated that the CES is a reliable and valid instrument for investigation of health status and health-related quality-of-life outcomes.     

Middle ear pathology can affect the ear-canal sound pressure generated by audiologic earphones

OBJECTIVE: To determine how the ear-canal sound pressures generated by earphones differ between normal and pathologic middle ears. DESIGN: Measurements of ear-canal sound pressures generated by the Etymtic Research ER-3A insert earphone in normal ears (N = 12) were compared with the pressures generated in abnormal ears with mastoidectomy bowls (N = 15), tympanostomy tubes (N = 5), and tympanic-membrane perforations (N = 5). Similar measurements were made with the Telephonics TDH-49 supra-aural earphone in normal ears (N = 10) and abnormal ears with mastoidectomy bowls (N = 10), tympanostomy tubes (N = 4), and tympanic-membrane perforations (N = 5). RESULTS: With the insert earphone, the sound pressures generated in the mastoid-bowl ears were all smaller than the pressures generated in normal ears; from 250 to 1000 Hz the difference in pressure level was nearly frequency independent and ranged from -3 to -15 dB; from 1000 to 4000 Hz the reduction in level increased with frequency and ranged from -5 dB to -35 dB. In the ears with tympanostomy tubes and perforations the sound pressures were always smaller than in normal ears at frequencies below 1000 Hz; the largest differences occurred below 500 Hz and ranged from -5 to -25 dB. With the supra-aural earphone, the sound pressures in ears with the three pathologic conditions were more variable than those with the insert earphone. Generally, sound pressures in the ears with mastoid bowls were lower than those in normal ears for frequencies below about 500 Hz; above about 500 Hz the pressures showed sharp minima and maxima that were not seen in the normal ears. The ears with tympanostomy tubes and tympanic-membrane perforations also showed reduced ear-canal pressures at the lower frequencies, but at higher frequencies these ear-canal pressures were generally similar to the pressures measured in the normal ears. CONCLUSIONS: When the middle ear is not normal, ear-canal sound pressures can differ by up to 35 dB from the normal-ear value. Because the pressure level generally is decreased in the pathologic conditions that were studied, the measured hearing loss would exaggerate substantially the actual loss in ear sensitivity. The variations depend on the earphone, the middle ear pathology, and frequency. Uncontrolled variations in ear-canal pressure, whether caused by a poor earphone-to-ear connection or by abnormal middle ear impedance, could be corrected with audiometers that measure sound pressures during hearing tests.