Biocomplexity in a highly migratory pelagic marine fish, Atlantic herring.

The existence of biologically differentiated populations has been credited with a major role in conferring sustainability and in buffering overall productivity of anadromous fish population complexes where evidence for spatial structure is uncontroversial. Here, we describe evidence of correlated genetic and life history (spawning season linked to spawning location) differentiation in an abundant and highly migratory pelagic fish, Atlantic herring, Clupea harengus, in the North Sea (NS) and adjacent areas. The existence of genetically and phenotypically diverse stocks in this region despite intense seasonal mixing strongly implicates natal homing in this species. Based on information from genetic markers and otolith morphology, we estimate the proportional contribution by NS, Skagerrak (SKG) and Kattegat and western Baltic (WBS) fish to mixed aggregations targeted by the NS fishery. We use these estimates to identify spatial and temporal differences in life history (migratory behaviour) and habitat use among genetically differentiated migratory populations that mix seasonally. Our study suggests the existence of more complex patterns of intraspecific diversity than was previously recognized. Sustainability may be compromised if such complex patterns are reduced through generalized management (e.g. area closures) that overlooks population differences in spatial use throughout the life cycle.

The chest radiograph in cystic fibrosis: a new scoring system compared with the Chrispin-Norman and Brasfield scores.

BACKGROUND: Scoring systems for the chest radiograph in cystic fibrosis are used to compare patients and different treatment regimens, and to monitor respiratory disease in individual patients. The Northern chest radiograph score was designed to allow one person to assess the radiological features of lung involvement in cystic fibrosis in as simple, rapid and equally reproducible manner as the established Chrispin and Norman, and Brasfield scoring systems. METHODS: Forty five chest radiographs were scored by 10 physicians with a special interest in cystic fibrosis according to the Brasfield and Northern methods, and by five pairs of physicians according to the Chrispin-Norman criteria. Three individuals and two pairs rescored the radiographs after an interval of 3-5 months. The Northern score was performed with and without a lateral view, using the original posteroanterior radiograph. RESULTS: The Northern score showed a better agreement between observers for the ranking of the radiographs. It was equally well related to respiratory function tests, the Shwachman-Kulczycki score of overall clinical status, and in its discrimination between different radiographs as the other two scoring systems. The Northern score performed equally well with or without a lateral film. CONCLUSIONS: The Northern system fulfils the requirements of a chest radiograph score more successfully than the Chrispin-Norman or Brasfield systems, and does not require a lateral film.

Aspergillus fumigatus colonisation and population density of place of residence in cystic fibrosis.

The relation between antibody titres of aspergillus in patients with cystic fibrosis and the population density of their place of residence was investigated. Patients with high titres of antibodies to Aspergillus fumigatus were significantly more likely to live in an area of low population density. Living in a rural environment may predispose to A fumigatus colonisation.

Changes in nocturnal oximetry after treatment of exacerbations in cystic fibrosis.

Sleep related arterial oxygen desaturation has been described in clinically stable young adults with cystic fibrosis. The incidence and severity of nocturnal oxygen desaturation in children during infective exacerbations and the changes that occur with treatment were examined. Forty five children with proved cystic fibrosis, median age 8.9 years, admitted to the Regional Cystic Fibrosis Unit underwent clinical evaluation, spirometry, and measurement of peak flow and nocturnal oxygen saturation on admission and after 10 days' treatment. There was a significant improvement in all the above measurements, with the averaged overnight saturation changing from a mean (SD) 92.7 (2.7)% to 94.3 (2.0)%, mean (SE) difference 1.58 (0.37). The time spent with a saturation 4% or more below their clinic value showed a marked improvement from 122 (152) minutes on the first night to 21 (30.7) on the second, mean (SE) difference 101 (22.4). Eight young children could not perform pulmonary function tests, all desaturated on the admission night. Nocturnal hypoxaemia is a common finding in young cystic fibrosis patients during infective exacerbations but improves with treatment. Overnight oximetry is simple to perform, well tolerated, and identifies patients with marked nocturnal desaturation.

The value of serum IgG titres against Pseudomonas aeruginosa in the management of early pseudomonal infection in cystic fibrosis.

We report the results of a clinical trial. Patients enrolled had serum IgG titres against Pseudomonas aeruginosa above the control range. Assignment to the observation or treatment group was by minimisation. Significant signs or symptoms in any patient prompted antipseudomonal treatment. In addition, the treatment group received antipseudomonal treatment at intervals of four months until the serum IgG titre returned to the control range. P aeruginosa was isolated intermittently from patients in the main trial. Nineteen patients were enrolled (12 observation, seven treatment). After one year in the trial changes in parameters studied, including forced expiratory volume in one second, IgG titre, serum IgG concentrations, and frequency of P aeruginosa isolation had improved in the treated group and worsened in the observation group.

Acute severe deterioration in cystic fibrosis associated with influenza A virus infection.

BACKGROUND: The role of non-bacterial infection in respiratory exacerbations of cystic fibrosis has been studied less than that of bacterial infection. Some non-bacterial infections, such as influenza A, may be associated with acute respiratory deterioration and may be preventable. METHODS AND RESULTS: Three patients with cystic fibrosis showed severe deterioration in lung function and general wellbeing during the influenza A virus epidemic in the winter of 1989-90. Serological confirmation of influenza A virus infection was obtained in each case. CONCLUSIONS: As immunisation against influenza A virus is safe and provokes an adequate antibody response in patients with cystic fibrosis, it is concluded that patients with cystic fibrosis should be offered immunisation at the beginning of each influenza season. Rapid diagnostic tests and the use of antiviral drugs may have a prophylactic role in minimising lung damage.

First day serum creatine kinase BB isoenzyme in high-risk infants.

Serum creatine kinase BB (CK-BB) on the 1st day of life was measured by radioimmunoassay in 37 very low birth weight (VLBW) infants, 14 severely asphyxiated infants and 24 controls. The 31 survivors from the two high-risk groups were followed up for 12 months or more. VLBW non-survivors (n = 14) had significantly higher mean CK-BB levels than survivors (n = 23), (P less than 0.05). However, if only survivors were considered, CK-BB was a poor discriminator of outcome in either study group. First day serum CK-BB is not a useful predictor of neurodevelopmental outcome in surviving high-risk infants.

Pseudomonas cepacia: a new pathogen in patients with cystic fibrosis referred to a large centre in the United Kingdom.

Pseudomonas cepacia infection has become increasingly common among patients with cystic fibrosis in North America. In a large cystic fibrosis centre in the United Kingdom 11 cases have been identified during the last six years, with a maximum prevalence of 7% in 1988. Three patients have died, two of whom deteriorated rapidly shortly after acquisition of the organism despite intensive treatment with appropriate antibiotics. Analysis of possible causes of the increase in P cepacia infection suggested that neither patient to patient transmission nor the use of nebulised antibiotics was associated with an increased risk of infection.

Cystic fibrosis and allergic bronchopulmonary aspergillosis.

We have prospectively screened our patients with cystic fibrosis for allergic bronchopulmonary aspergillosis. Over a three year period eight patients were identified, an incidence of 5.8%. Patients were clinically well at the time of diagnosis (Shwachman scores 70-90, Chrispin-Norman chest x ray scores 2-15) and they responded rapidly to treatment with oral prednisolone. There has been little deterioration in their respiratory function and nutrition over the study period. We conclude that allergic bronchopulmonary aspergillosis is not uncommon in patients with cystic fibrosis. It is a potential cause of lung damage and prospective screening could lead to earlier detection and treatment.

The effectiveness of two methods for teaching a constraint-seeking questioning strategy to students with learning disabilities.

This study investigated the relative effectiveness of two methods of teaching an efficient questioning strategy to students with learning disabilities. The methods compared were (a) cognitive modeling alone in the use of constraint-seeking questions, and (b) cognitive modeling and verbalization in the use of constraint-seeking questions, involving explicit and consistent instruction and feedback. Sixty subjects with learning disabilities were assigned randomly to one of these two conditions (n = 30 in each group). A pretreatment and posttreatment design was employed, with the criterion variable being number of questions required to obtain the correct answers to two 20 questions games. Results indicated that both groups showed significant reductions from pretreatment to posttreatment in the number of questions required. The two methods of instruction did not differ significantly in effectiveness.

Fractional measurements of sweat osmolality in patients with cystic fibrosis.

After pilocarpine iontophoresis the change of sweat concentration during collection was studied by vapour pressure osmometry in 24 patients with cystic fibrosis and 24 healthy controls. There was a continuous but proportionate fall in sweat concentrations during the collection period. Mean (SD) initial sweat concentration in the control group was 154.4 (32.6) mmol/kg falling, after 50 microliters of sweat produced, to 92.9 (15.8) mmol/kg. In the cystic fibrosis group it was 315.9 (35.8) mmol/kg falling to 247.4 (24.9) mmol/kg. Despite different rates of fall in concentrations, separation of the two groups was maintained throughout. We conclude that there are implications for the potential improvement of the predictive value of the sweat test.

Cystic fibrosis and renal tubular acidosis.

A case is reported of a child who was born to consanguineous parents and who had the clinical features of two autosomal recessive conditions--cystic fibrosis and distal renal tubular acidosis.

Neonatal typhoid fever.

Three infants of Pakistani immigrant mothers developed typhoid fever in the neonatal period. All three survived, but two became chronic excretors of Salmonella typhi. The risk of an outbreak of typhoid fever in a maternity unit or special care baby unit is emphasized.