Spatiotemporal patterns of secretomotor neuron generation in the parvicellular neuroendocrine system

Spatiotemporal patterns of parvicellular neurosecretory neuron generation (birthdates) were determined in the young adult male rat using a triple fluorescence labeling method. The six classic phenotypes were identified in histological sections with rabbit antisera to neurotransmitters (or related enzymes), nuclear bromodeoxyuridine was detected with a mouse monoclonal antibody, and an axonal projection to the median eminence was determined with the fluorescent retrograde tracer fast blue. The vast majority of triply labeled neurons are generated between embryonic days 12-14, during the time when magnocellular neurosecretory neurons are also generated. This pattern of neurogenesis is distinct from the well-known 'outside-in' pattern of hypothalamic neurogenesis, where the peak of lateral zone birthdates occurs on embryonic days 12 and 13, the peak of medial zone birthdates occurs on embryonic days 14 and 15, and the peak of periventricular zone birthdates occurs on embryonic days 16 and 17. Thus, neuroendocrine motoneurons may constitute 'pioneer neurons' for the various anatomically distinct regions of the periventricular zone. In addition, many intermixed neurons that express the same neurotransmitters as parvicellular neurosecretory neurons but do not send an axon to the median eminence, also appear to be generated between embryonic days 12 and 14. What these results imply about mechanisms underlying neuroendocrine motor zone differentiation is discussed.     

Children referred for specialist care: a nationwide study in Dutch general practice

BACKGROUND: Insight into referral patterns provides general practitioners (GPs) and specialists with a frame of reference for their own work and enables assessment of the need for secondary care. Only approximate information is available. AIM: To determine how often, to which specialties and for what conditions children in different age groups are referred, as well as how often a condition is referred given the incidence in general practice. METHOD: From data of the Dutch National Survey of Morbidity and Interventions in General Practice, 63,753 new referrals (acute and non-acute) were analysed for children (0-14 years) from 103 participating practices (161 GPs) who registered. Practices were divided into four groups. Each group of practices participated for three consecutive months covering a whole year altogether. We calculated referral rates per 1000 children per year and referability rates per 100 episodes, which quantifies the a priori chance of a condition being referred for specialist care. RESULTS: The referral rate varied by age from 231 for children under 1 year old to 119 for those aged 10-14 years (mean 159). The specialties mainly involved were ENT, paediatrics, surgery, ophthalmology, dermatology and orthopaedics. Referrals in the first year of life were most frequently to paediatricians (123); among older children the referral rate to paediatricians decreased (mean 36). Referrals to ENT specialists were seen particularly in the age groups 1-4 (71) and 5-9 (53). For surgery, the referral rate increased by age from 19 to 34. Differences between boys and girls were small, except for surgery. The highest referral rates were for problems in the International Classification of Primary Care (ICPC) chapters: respiratory (28); musculoskeletal (25); ear (24) and eye (21). Referability rates were, in general, low for conditions referred to paediatrics and dermatology and high for surgery and ophthalmology. The variation in problems presented to each specialty is indicated by the proportion of all referrals constituted by the 10 most frequently referred diagnoses: from 35% for paediatrics to 81% for ENT; for ophthalmology, five diagnoses accounted for 83% of all referrals. CONCLUSIONS: The need for specialist care in childhood is clarified with detailed information for different age categories, specialties involved and variation in morbidity presented to specialists, as well as the proneness of conditions to be referred.     

The copper chaperone for superoxide dismutase

Copper is distributed to distinct localizations in the cell through diverse pathways. We demonstrate here that the delivery of copper to copper/zinc superoxide dismutase (SOD1) is mediated through a soluble factor identified as Saccharomyces cerevisiae LYS7 and human CCS (copper chaperone for SOD). This factor is specific for SOD1 and does not deliver copper to proteins in the mitochondria, nucleus, or secretory pathway. Yeast cells containing a lys7Delta null mutation have normal levels of SOD1 protein, but fail to incorporate copper into SOD1, which is therefore devoid of superoxide scavenging activity. LYS7 and CCS specifically restore the biosynthesis of holoSOD1 in vivo. Elucidation of the CCS copper delivery pathway may permit development of novel therapeutic approaches to human diseases that involve SOD1, including amyotrophic lateral sclerosis.     

Ionic strength effect on the thermal unfolding of alpha-spectrin peptides

In previous work, we have shown that the ionic strength-mediated differences found for the hydrodynamic dimensions of the human erythrocyte spectrin are not caused by secondary structural changes, but are caused more probably by subtle changes in tertiary interactions (LaBrake, C. C., Wang, L., Keiderling, T. A., and Fung, L. W.-M. (1993) Biochemistry 32, 10296-10302.). The substructure of spectrin has been suggested to be composed largely of triple alpha-helical bundle structural domains in tandem. In the present study, we used fluorescence and circular dichroism methods to study ionic strength effects on intact spectrin dimers and on recombinant peptides of spectrin domains of different lengths. We observed little ionic strength effect on the thermal unfolding temperature, Tm, values in these systems. However, we found that ionic strength-induced cooperativity in the unfolding processes was similar for the spectrin dimer and for peptides with two or three domains, as measured by entropy changes (DeltaSm). Although single-domain peptides exhibited rather variable DeltaSm values, depending on the specific domain, they showed little salt effects on the DeltaSm values themselves. This suggests that spectrin undergoes subtle ionic strength-induced conformational changes, probably near the interdomain regions of the molecule. These conformational changes may be responsible for the observed hydrodynamic and unfolding properties in intact spectrin under different ionic strength conditions. We suggest that recombinant peptides of various lengths may serve as models for studying the structural flexibility in spectrin.     

Parental antecedents of adult codependency

Two aspects of codependency were investigated among 442 undergraduates. First, parental antecedents were examined by subjects completing measures of codependency, perceived parental dysfunctions (compulsivity, chemical dependency, and codependency), and parental styles (coercion, control, and non-nurturance). As expected, correlations between adult codependency and parental coercion, control, non-nurturance, and maternal compulsivity were significant. However, correlations between codependency and parental chemical dependency were not significant. A multiple regression analysis identified parental codependency and maternal coercion as significant predictors of subject codependency. To examine the second aspect of codependency, which assumes that codependency was identified over 40 years ago by Karen Horney, subjects completed a loss of self measure which correlated highly with codependency.     

Over one-half billion years of head conservation? Expression of an ems class gene in Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa)

We report the isolation of an empty spiracles class homeodomain-containing gene, Cn-ems, from the hydrozoan Hydractinia symbiolongicarpus, the first gene of this class characterized in a lower metazoan. Cn-ems was found to be expressed in the head of gastrozooids, specifically in endodermal epithelial cells of the taeniolae of the hypostome. Cn-ems is not expressed in gonozooids, which lack taeniolae. Experimental conversion of the posterior region of the planula larva into head structures up-regulates expression of the gene. These findings establish that the association of ems-class genes with head structures preceded the evolution of bilateral symmetry.     

Genetic dissection of a mammalian replicator in the human beta-globin locus

The timing and localization of DNA replication initiation in mammalian cells are heritable traits, but it is not known whether initiation requires specific DNA sequences. A site-specific recombination strategy was used to show that DNA sequences previously identified as replication initiation sites could initiate replication when transferred to new chromosomal locations. An 8-kilobase DNA sequence encompassing the origin of DNA replication in the human beta-globin locus initiated replication in the simian genome. Specific deletions within the globin origin did not initiate replication in these chromosomal sites. These data suggest that initiation of DNA replication in mammalian cells requires specific sequence information and extend the replicon hypothesis to higher eukaryotes.     

Reactive arthritis in patients attending an urban sexually transmitted diseases clinic

OBJECTIVE: To assess the prevalence, clinical manifestations, associated genital infections, and HLA associations of reactive arthritis (ReA) among patients attending an urban sexually transmitted diseases (STD) clinic. METHODS: Using a standardized questionnaire, 271 consecutive adults, primarily black, with possible or proven Chlamydia trachomatis genital infection were screened for symptoms of ReA. A followup questionnaire was administered 6 weeks later by mail. Patients who reported at least 1 symptom were evaluated by a rheumatologist. HLA-B typing was performed on patients with objective ReA features. RESULTS: Nine of 217 patients (4.1%) with genital infection/inflammation had objective ReA features. Chlamydial or nongonococcal STD syndromes were diagnosed in 8 of these 9 patients (88%). Genital infection/inflammation was asymptomatic in 78% of patients with ReA features. HLA-B27 or other B7-cross-reactive group antigens were not associated with the occurrence of ReA. CONCLUSION: Nongonococcal genital infections, often asymptomatic, can trigger a relatively mild ReA in a larger number of exposed patients than previously thought, irrespective of the individual's HLA status.     

Measuring the progression of foreign-body reaction to silicone implants using in vivo MR microscopy

We used in vivo magnetic resonance (MR) microscopy to follow the growth of fibrous capsule as a foreign body reaction to silicone implants in rats. Anesthetized rats were imaged 1, 7, 14, and 28 days after silicone-coated MR imaging coils were sutured to their neck muscles. On the twenty-eighth day, rats were sacrificed and coils and adjacent tissues were removed en bloc and fixed in formalin, reimaged with MR, and sectioned for conventional histology. Three-dimensional (3-D) spin-echo [3DFT] acquisition gave in-plane resolution of 32 x 32 microns in vivo and 16 x 16 microns ex vivo. All MR images showed a diffuse band of elevated signal intensity between the silicone of the coil and adjacent tissue. The border of the hyperintense band was thin and not well defined at seven days post-implantation. From 7-28 days, the band showed relatively homogeneous signal intensity and its thickness increased 44% on the rectus muscle side and 78% on the subcutaneous side. The capsule thickness determined either by MR in vivo and ex vivo microscopy or conventional histology was not significantly different, and there was a significant correlation between thickness measurements among those methods. MR in vivo microscopy provides sufficient resolution and spatial information to serially evaluate the growth of the foreign body fibrous capsule over time, thus achieving greater accuracy and consistency in measurements.