Contrasting dynamics in the same plant-herbivore interaction

Long-term studies of two-species interactions under field conditions are unusual; most long-term field studies are of single species dynamics (1-6). Concurrent long-term studies on the dynamics of the same two interacting species in different locations are very rare. This result has led to the tacit assumption that different cases of the same two-species interaction would involve essentially quantitative differences (e.g., context-specific differences in the numeric values of demographic parameters like fecundity or death rates). Here, we show that for one of the best-known two-species systems (ragwort and cinnabar moth), this finding does not hold. The interaction between the plant and its herbivore is fundamentally different in coastal dunes in The Netherlands and in grasslands in Southeast England. In the first case, the dynamics are cyclic and the interaction involves both direct and delayed density dependence; in the second case, the insect has little impact on plant dynamics and there are no time lags in density dependence. The difference is caused by differences in the importance of seed-limitation in plant recruitment in the two locations.     

Reducing dose at barium enema: radiographers do it digitally

It has been previously shown that, whilst radiographers in our hospital can undertake barium enema examinations with the same degree of diagnostic accuracy as consultant radiologists, there was a dose penalty to the patient arising from the use of a restrictive protocol requiring radiographers to take a series of plain radiographs for reporting purposes. For the past 3 years radiographers at this hospital have worked to a new protocol that replaces all routine radiographs with digital spot films. In the present study, dose-area product (DAP) measurements for 801 barium enema examinations performed by consultant radiologists and radiographers, using the revised protocol, were analysed and compared to ascertain whether there were still significant differences in radiation dose to the patient depending on the category of staff performing the examination. All examinations were reported by a consultant radiologist. The radiologists' reports were analysed against the known outcomes to compare the diagnostic accuracy of the examination when carried out by the two categories of staff. This study shows that using a modified protocol, in which digital spot films replace the series of overcouch radiographs for reporting, our radiographers are able to perform barium enemas without dose penalty to the patient, and without compromizing diagnostic accuracy. Means with 95% confidence intervals for DAP in the two groups were 9.8 Gycm(2) (9.4-10.3 Gycm(2)) and 10.7 Gycm(2) (10.2-11.1 Gycm(2)) for radiographers and radiologists, respectively.     

Nasal inflammation and chronic ear disease in Australian Aboriginal children

Objective : Chronic middle ear disease is common in Aboriginal children, and may be linked to nasal inflammation and Eustachian tube dysfunction. The pattern of nasal inflammation is unknown. The study reported here was performed to define the role of allergy and infection in causing nasal inflammation in Aboriginal children with chronic middle ear disease.
Methodology : Thirty-one Aboriginal children aged between 3 and 7 years underwent clinical assessment, audiometry and allergy skin tests. Nasal swabs for bacterial culture and cytology were performed during the winter and again in spring to identify any seasonal variation. A randomized trial of nasal beclomethasone for 8 weeks was conducted in children with abnormal tympanometry to identify the effect of therapy upon nasal cytology.
Results : Twenty-six of the 31 children had abnormal tympanograms. Average hearing levels were reduced in nine children. Pathogenic organisms were isolated from most children: Streptococcus pneumoniae (82%), Haemophilus influenzae (79%), Moraxella catarrhalis (39%) and Staphylococcus aureus (29%). Eight of the 31 children (26%) were atopic. Nasal cytology disclosed a marked neutrophil infiltrate (80% of cells) during the winter, which fell significantly in spring to 52% of cells. Only two subjects had nasal eosinophilia of >10%. There was no effect of beclomethasone on nasal cytology.
Conclusions : Chronic ear disease in Aboriginal children is associated with nasal inflammation, neutrophil infiltration and the presence of bacteria. These features suggest respiratory infection as the main cause of chronic nasal inflammation in Aboriginal children with middle ear disease. There is a seasonal variation in the severity of the nasal infiltrate, consistent with increased infections during winter. Despite a high prevalence of atopy, allergic nasal disease was uncommon.     

Pericardial effusion complicating a percutaneous central venous line in a neonate

A premature infant developed pericardial effusion four days after the insertion of a 25-gauge silastic percutaneous central venous catheter. The effusion contained parenteral nutrition fluid and resolved rapidly after withdrawal of the catheter. Pericardial effusion is a potential complication of percutaneous, as well as surgically placed, central venous catheters.     

Mental health and psychosocial functioning in adolescents with congenital heart disease. A comparison between adolescents born with severe heart defect and atrial septal defect

Twenty-six adolescents, aged 13–18 years, with severe congenital heart disease were matched for sex, age and living area with 26 adolescents with repaired atrial septal defect and regarded as physically fit. These two groups were compared according to somatic condition, psychopathology, psychosocial functioning and chronic family difficulties. A higher rate of psychiatric problems in the complex group, an association between psychosocial functioning and physical capacity, as well as an association between psychosocial functioning and chronic family difficulties were observed. These findings suggest that physical capacity is of crucial importance for mental health and functioning of adolescents with congenital heart disease. The association with chronic family difficulties also suggests that a comprehensive biopsychosocial approach is necessary in the treatment and rehabilitation of these patients.     

Auxology and response to growth hormone treatment of patients with intrauterine growth retardation or Silver-Russell syndrome: analysis of data from the Kabi Pharmacia International Growth Study

Using the database from the Kabi Pharmacia International Growth Study, 105 patients with intrauterine growth retardation (IUGR) (82 males, 23 females) and 45 with Silver-Russell syndrome (SRS) (32 males, 13 females) with persistent postnatal growth failure were studied. Patients with IUGR had a birth length and birth weight more than 2 SD below the mean for gestational age. Their height deficit at the start of GH treatment was -3.0 SDS at a median chronological age of 8.7 years and a median bone age of 7.0 years. Mean paternal and maternal heights were 166 and 153 cm, respectively. The median dose of GH was 0.5 IU/kg/week, given at a median frequency of five injections/week. The median height SDS for chronological age after 1, 2 and 3 years of GH treatment were -2.5, -2.1 and -1.9, respectively. In the 45 patients with SRS, median chronological age and median bone age at the start of treatment were 6.7 and 3.2 years, respectively, and mean paternal and maternal heights were 167.5 and 160 cm, respectively. The median dose of GH was 0.7 IU/kg/week, given at a median frequency of six injections/week. The median height SDS for chronological age at the start of treatment and after 1, 2 and 3 years were -3.5, -2.9, -2.8 and -2.2, respectively. Although the criteria used by physicians when diagnosing SRS were not controlled or verified in this study, it appears that patients with SRS can be differentiated from those with IUGR with persistent growth failure by their reduced bone age for chronological age at the start of treatment, and by the fact that patients with SRS tended to be born to parents of normal height. GH treatment in both groups induced catch-up growth, though long-term follow-up studies will be required to assess the effects of treatment on final height.     

Urinary albumin excretion and transcapillary escape rate of albumin in malignancies

Transcapillary escape rate of albumin was determined in 22 patients with different malignancies. In addition, urinary albumin excretion rate was measured in 24-h urine samples using a sensitive immunoassay. Increased urinary albumin excretion was defined as ≥20 μg/min according to conventional standards. Renal glomerular filtration and tubular function was estimated by⁵¹Cr-EDTA plasma clearance and urinary beta 2-microglobulin, respectively. Median urinary albumin excretion rate was 15.0 μg/min (range 6–510 μg/min) and the frequency of increased urinary albumin excretion was 41%. This agrees with other studies showing increased albuminuria in several types of malignant diseases. Patients with advanced disease (tumour, node, metastasis (TNM) stage II–IV) had a significantly higher urinary albumin excretion rate than patients with localized disease (TNM stage I). Serum creatinine, glomerular filtration rate and urinary beta 2-microglobulin were all within normal limits. Median transcapillary escape rate of albumin was 5.5%/h (range 2–8%/h) and this level is comparable with values in healthy subjects. There was no significant difference in transcapillary escape rate between patients with elevated urinary albumin excretion and the normoalbuminuric group. Median value of the absolut outflux of albumin was 10.6 g/h with similar levels in patients with increased urinary albumin excretion and patients with normoalbuminuria. Our results indicate a high prevalence of minor glomerular dysfunction with a slightly elevated urinary albumin excretion in patients with malignancies. The normal endothelial function, as estimated by the transcapillary escape rate of albumin, suggests an overal unaffected capillary permeability and increased urinary albumin loss appears to be an isolated renal phenomenon in cancer patients.     

Expression of tyrosine hydroxylase in cerebellar Purkinje neurons of the mutant tottering and leaner mouse.

In situ hybridization histochemistry, Northern blot analysis and immunohistochemistry were used to examine tyrosine hydroxylase (TH) mRNA concentrations and immunoreactivity in the locus coeruleus and cerebellum of the tottering (tg/tg), leaner (tgla/tgla), compound heterozygous (tg/tgla) and wild type control (+/+) mice, bred on a C57BL/6J background. Cerebellar Purkinje neurons, long considered to be GABAergic, showed high levels of TH mRNA in the caudal vermis and the lateral hemispheres of the cerebellum of tg/tg, tg/tgla, and tgla/tgla mice. Analysis of grain density over individual Purkinje cells showed significantly greater concentrations of TH mRNA in tg/tg, tg/tgla, and tgla/tgla mice as compared to +/+ wild type control mice. Comparison of adult (greater than or equal to 2 months) and young, pre-seizure (less than or equal to 3 weeks) mutant mice showed Purkinje cells densely labelled for TH mRNA at both ages, suggesting that TH gene expression in Purkinje cells is independent of the onset of seizures. Northern blot analysis confirmed the findings from the in situ hybridization studies, demonstrating a single band identical to TH mRNA. Immunohistochemistry confirmed the presence of TH protein in Purkinje cells of the caudal vermis and the lateral hemispheres of the cerebellum in both control and mutant mice. Quantitation of mRNA for TH and the coexisting neuropeptide, galanin, in the locus coeruleus detected no significant differences between adult tg/tg, tg/tgla and +/+ control mice. The present findings demonstrate that the classically GABAergic Purkinje cells in the cerebellum express low levels of TH, and that the mutant tottering and leaner strains of mice express extremely high levels of mRNA and protein for TH.