Use of E mu-PIM-1 transgenic mice short-term in vivo carcinogenicity testing: lymphoma induction by benzo[a]pyrene, but not by TPA

E mu-pim-1 transgenic mice are predisposed to develop lymphomas. Due to their low spontaneous tumour incidence and their increased sensitivity towards the lymphomagen ethylnitrosourea these mice may present an interesting model for short-term carcinogenicity testing. Here, we report on the further exploration of this transgenic mouse model with two additional carcinogens known to have, among others, the lymphohaematopoietic system as target, i.e. benzo[a]pyrene (B[a]P) and 12-O-tetradecanoylphorbol-13-acetate (TPA). B[a]P, given three times a week (by gavage) for 13 weeks at 4.3, 13 or 39 mg/kg body weight, resulted in a dose-related increase in lymphomas up to a 90% incidence in E(mu)-pim-1 mice during the observation period of 40 weeks. B[a]P also induced tumours of the forestomach within this observation period, though at a lower incidence and apparently equally effective in wildtype and transgenic mice. TPA, on the other hand, was unable to induce lymphomas (or tumours in any other organ) in either transgenic or wildtype animals within the observation period of 44 weeks, when applied dermally at the maximum tolerated dose of 3 microg/mouse, twice a week for 35 weeks. Molecular analysis showed that B[a]P-induced lymphomas in transgenic mice were of T-cell origin, 80% of which had elevated levels of c-myc expression. None of the lymphomas had increased N-myc expression and mutation analysis of the ras-gene family revealed a K-ras mutation in only one out of eight tumours investigated. Also, none of the lymphomas showed aberrant expression of p53 as determined by immunohistochemistry. It is concluded that the E mu-pim-1 mouse model will not be very suitable for short-term carcinogenicity testing in general: only genotoxic chemicals that have the lymphohaematopoietic system as target for carcinogenesis in wild- type mice, appear to be efficiently identified.      

Thoracic empyema: a study of 56 patients

Fifty seven children with thoracic empyema (37 boys and 20 girls) aged less than 12 years were seen at the University of Port Harcourt Teaching Hospital between January 1989 and December 1991. Staphylococcus aureus was the most common organism isolated from the pus of these patients (36 (63%) patients). Pseudomonas aeruginosa, the next most common organism, was isolated in 10 (18%) patients. The most common symptoms at presentation were acute illness with fever and cough (51 (89%) patients). All the patients were treated with closed intercostal tube drainage and appropriate antibiotics. Decortication was resorted to in only one patient. There were two deaths and the overall survival rate was 97%.     

Comparison of magnetometer and inductance plethysmography derived Konno-Mead diagrams during CO2 rebreathing

Magnetometers measure changes in antero-posterior diameters of the rib cage and abdomen while respiratory inductance plethysmography (RIP) measures changes in chest wall cross-sectional area. We compared Konno-Mead diagrams derived from isovolume calibrated magnetometers and RIP in the DC-mode during room air and CO2 rebreathing in the sitting and supine positions. Chest wall configurations obtained during quiet tidal breathing were similar in both sitting and supine positions. During CO2 stimulated breathing, however, derived chest wall configurations were at times dissimilar. The RIP per cent rib cage contribution to tidal volume was greater than that of magnetometers during room air and CO2 rebreathing in both sitting and supine positions. Changes in end expiratory levels measured by magnetometers and RIP during CO2 rebreathing are in general proportionate to each other; however, the magnetometers usually depicted quantitatively greater decreases in abdominal end expiratory levels during rebreathing. We conclude that the qualitative and quantitative assessment of chest wall configurations and volume displacement vary depending on the method used. RIP by including lateral wall motion may more accurately reflect compartmental displacements, while magnetometers by solely measuring antero-posterior diameter may better reflect changes in abdominal volume and thus diaphragm configuration.     

Mature spinal teratoma associated with thickened filum terminale

A 30-year-old man presented with an intradural spinal teratoma with thickened filum terminale manifesting as urinary and sexual disturbances, and low back pain persisting for 4 years. Spinal magnetic resonance imaging revealed thickened filum terminale containing a heterogeneously enhanced intradural lesion extending from the L-3 to L-4 levels and in contact with the conus medullaris. The filum terminale was incised and the tumor was totally resected. The histological diagnosis was mature teratoma consisting of three germ cell layers. The patient's complaints had completely resolved 6 months later.     

Influenza and respiratory syncytial virus morbidity among 0-19 aged group in Yunus Emre Health Center

The objective of the study was to determine the morbidity of influenza and respiratory syncytial virus (RSV) infection in the 0-19 years of age group with influenza-like illness among the outpatient cases. From 20 January to 31 March 2003 a total of 123 subjects with upper respiratory tract infection attended Yunus Emre Health Center. Ninety-one subjects fit the case definition of influenza-like illness, which consisted of acute fever of more than 38 degrees C, cough, and sore throat. After obtaining their consent, nasal swabs were taken for isolation of influenza and RSV. Of these, 10 were influenza A virus, 6 were influenza B virus and 20 were RSV. All of influenza virus A was typed as subtype H3N2. The rates of influenza virus among 5-9 and 1-4 years of age groups and of RSV among 1-4 years of age group were high. The average number of absentee days of schoolchildren with influenza was 3.33 days and of those with RSV infection was 1.43 days; this rate was calculated as 2.25 days for the influenza-like illness. Continuous surveillance and influenza vaccination for target groups are recommended for beneficial effects of reducing influenza morbidity and mortality in the community.     

The effects of environmental light--dark changes on experimental mild traumatic brain injury

OBJECTIVES: The aim of this study was to investigate the effects of environmental light-dark changes on the outcome of mild traumatic brain injury (MTBI) using an experimental rodent model. The functions of endogenous and exogenous melatonin on the outcome of injury were also investigated METHODS: Mild traumatic brain injury was experimentally induced in 56 male Sprague-Dawley rats using a weight-drop device. Animals were divided into four groups of 14 each as follows: (i) sham-operated (trauma only, normal day-night cycle), (ii) treated with melatonin (trauma+melatonin, normal day-night cycle), (iii) darkness-induced (trauma+48 h constant dark), and (iv) treated with melatonin and darkness-induced (trauma+48 h constant dark+melatonin). Melatonin (50 mg/kg) was administered, intraperitoneally, immediately after trauma. EEG recordings were taken at three time periods (pretrauma, immediately after trauma, and 48 h after trauma). Motor functions were tested pretrauma, 24 and 48 h post-trauma. Serum melatonin levels were determined pretrauma and 48 h post-trauma. Tissue samples from right frontal area were taken 48 h after trauma for light and electron microscopic examinations. CONCLUSION: Following MTBI light deprivation alone and light deprivation in combination with exogenously administered melatonin indicated significant neuroprotective effects. Although there may be other important pathways, darkness-induced elevation in endogenous melatonin secretion appears to play an important role in this neuroprotective outcome.