The early ontogeny of neuronal nitric oxide synthase systems in the zebrafish.

To examine a putative role for neuronal nitric oxide synthase (nNOS) in early vertebrate development we investigated nNOS mRNA expression and cGMP production during development of the zebrafish Danio rerio. The nNOS mRNA expression in the central nervous system (CNS) and periphery showed a distinct spatio-temporal pattern in developing zebrafish embryo and young larvae. nNOS mRNA expression was first detected at 19 h postfertilisation (h.p.f.), in a bilateral subpopulation of the embryonic ventrorostral cell cluster in the forebrain. The number of nNOS mRNA-expressing cells in the brain slowly increased, also appearing in the ventrocaudal cell cluster from about 26 h.p.f., and in the dorsorostral and hindbrain cell cluster and in the medulla at 30 h.p.f. A major increase in nNOS mRNA expression started at about 40 h.p.f., and by 55 h.p.f. the expression constituted cell populations in differentiated central nuclei and in association with the proliferation zones of the brain, and in the medulla and retina. In parts of the skin, nNOS mRNA expression started at 20 h.p.f. and ended at 55 h.p.f. Between 40 and 55 h.p.f., nNOS mRNA expression started in peripheral organs, forming distinct populations after hatching within or in the vicinity of the presumptive swim bladder, enteric ganglia, and along the alimentary tract and nephritic ducts. Expression of nNOS mRNA correlated with the neuronal differentiation pattern and with the timing and degree of cGMP production. These studies indicate spatio-temporal actions by NO during embryogenesis in the formation of the central and peripheral nervous system, with possible involvement in processes such as neurogenesis, organogenesis and early physiology.

Identification and distribution of nitric oxide synthase in the brain of adult zebrafish.

Nitric oxide (NO) is proposed to be involved in developmental and plastic processes. We investigated the presence and distribution of nitric oxide synthase (NOS) in the zebrafish (Danio rerio) using molecular and histochemical techniques. A partial gene sequence corresponding to the neuronal NOS isoform (nNOS) was identified, and in situ hybridization revealed cellular nNOS mRNA expression throughout the brain of adult zebrafish, distributed in distinct central nuclei and in proliferation zones. NOS immunoreactivity and nicotinamide adenine dinucleotide phosphate diaphorase activity partly coincided with the nNOS mRNA expression, however was present also in additional neuronal and non-neuronal cell types. The results indicate the occurrence of different NOS isoforms in the adult brain, of which nNOS may participate in neurotransmission, and in mechanisms related to the continuous growth and neuronal plasticity of the teleost brain.

[Invasive pneumococcal infections in children from Troms, Nordland and Sor-Trondelag 1980-95]. / Invasive pneumokokkinfeksjoner hos barn fra Troms, Nordland og Sør-Trøndelag 1980-95.

Invasive pneumococcal infections may be severe. We have examined epidemiology, risk factors and outcome of these infections. In the years 1980-95, 76 children below the age of 15 with invasive pneumococcal infections were admitted to the hospitals in the counties of Troms, Nordland and Sør-Trøndelag in Norway. The incidence rate in children 0-2 years old was 10.3 cases per 100,000 persons per year, and 1.8 in children 3-14 years. Of the patients 24 had meningitis and 52 bacteraemia. All bacteriological isolates were sensitive to benzylpenicillin. Seven patients died and five developed sequelae. Thirty-one of the children had risk factors prior to the infection. Children with hypo- or hyperventilation at the time of arrival, and/or impaired circulation fared worse than those with normal findings. Children with underlying risk factors have a much higher frequency of invasive pneumococcal infections than other children. Patients who had impaired circulation or ventilation on admission have a bad prognosis for healthy survival.

Clinical judgement as a basis for choice of recall interval in child dental care?

OBJECTIVE: Extending recall intervals can be an important strategy for making children's dental care more efficient. The purpose of this study was to describe the recall intervals that the clinicians decided were appropriate for children and adolescents when they were instructed to extend and individualise the routines based on clinical judgement. In addition, the effect on recall interval of the profession of the clinician (dentist or dental hygienist), the child's age and the need for fillings were studied. DESIGN: In a four week period in 1995, all dentists and dental hygienists in one county in Norway reported recall intervals for 2,513 children aged 3 to 18 years. RESULTS: The mean current interval since the previous examination was 17.1 months (SD = 4.7 months) and the mean proposed interval until the next examination was 16.4 months (SD = 4.4 months). Approximately 50% of children were evaluated by the clinicians to be suitable for recall intervals of 20 months or more and 10% were assessed as requiring a new examination within 12 months. The length of the current recall interval, the age of the child, whether or not the child received fillings, and whether the decision-maker was a dentist or a dental hygienist were statistically significantly associated with the length of the proposed recall interval. CONCLUSIONS: Basing recall intervals on clinical judgement resulted in intervals longer than 12 months for the majority of the children.

Age-related refractive shifts in simple myopia.

BACKGROUND: An understanding of physiologic age-related shifts in myopic refractive errors is important to the refractive surgeon for the interpretation of long-term results, surgical planning, and patient counseling. This study characterizes the refractive stability of adult simple myopia with a retrospective study of 413 eyes. METHODS: Approximately 74,000 patient records were analyzed to identify 208 adults with -1.00 to -6.00 diopters (D) of myopia who were followed for more than 20 years at the Spokane Eye Clinic. Amounts of myopic shift (increase in myopia) and hyperopic shift (decrease in myopia) were identified and analyzed within the population. The results were compared to long-term studies of radial keratotomy. RESULTS: The mean changes per patient age decade were: 20s, -0.60 D; 30s, -0.39 D; 40s, -0.29 D; 50s, +0.28 D; 60s, +0.41 D. Reanalyzed Prospective Evaluation of Radial Keratotomy (PERK) study 10-year postoperative data demonstrated progressively increasing hyperopic shifts per decade, at least to age 50. CONCLUSION: The normal adult population with simple myopia differs from the general population and consists of a population subgroup that is relatively stable and other subgroups that experience significant refractive shift. The hyperopic shift after radial keratotomy appears to be surgically induced and may be larger than previously thought.

Clinical responses to subgingival application of a metronidazole 25% gel compared to the effect of subgingival scaling in adult periodontitis.

A newly developed metronidazole 25% dental gel was compared with subgingival scaling in the treatment of adult periodontitis. 206 patients in 9 centres participated in the study. Probing pocket depth (PPD) and bleeding on probing (BOP) were recorded before treatment and 2, 6, 12, 18, and 24 weeks after the treatment. All patients had at least 1 tooth in each quadrant with a PPD of 5 mm or more. The treatments consisted of 2 applications of dental gel (days 0 and 7) in 2 randomly selected quadrants (split mouth design) and 2 sessions of subgingival scaling (1 quadrant on day 0, and 1 quadrant on day 7). Instruction in oral hygiene was given 2 weeks after completed treatment. The average PPD and the average frequency of BOP were calculated over all sites with initial PPD of 5 mm or more. PPD and BOP were thus, at each examination, calculated from the same sites. The mean PPD was 5.9 mm before gel application and 5.8 mm before scaling (p = 0.31). BOP was 88% in both treatment groups. 24 weeks after the treatment, PPD and BOP were significantly reduced in both groups and for both parameters (p < 0.01). PPD was reduced by 1.3 mm after gel application and 1.5 mm after scaling; BOP was reduced by 32% and 39%, respectively. The difference between the treatments was statistically significantly, but considered as clinically unimportant.