[Reduction of radiation dosage by using digital luminescence radiography on a hand phantom]

PURPOSE

How much can the radiation dose be reduced for hand radiography by using digital luminescence radiography (DLR)?

METHODS AND MATERIALS

A hand phantom (3M) with a cyst, two fractures and an "amputation" was digitally exposed in an anterior-posterior orientation using DLR (ADC-70, Agfa). The tube current time product (mAs) was reduced gradually while keeping the voltage constant. The surface entrance dose was measured by a Dosimax sensor (Wellhöfer). Five investigators evaluated the images for characteristics and critical features, pathological findings, visual resolution and contrast.

RESULTS

The surface entrance dose at 50 kV/5 mAs was 31 microGy. The images could be evaluated very well down to an average dose of 36% (11 microGy); sufficient images were obtained down to an average dose of 26% (8 microGy). The resolution of the line pairs was the same or reduced by 1 level depending on the investigator. Contrast was assessed as being very good to sufficient.

CONCLUSION

For the sufficient exclusion of a fracture the dose can be reduced to at least 39%, for the sufficient assessment of bony union and possible inflammatory changes to at least 42%, to position check and foreign body search to at least 23%. By DLR the following question-referred mAs-product at 50 kV are stated: fracture exclusion 2 mAs, bony union, arthritis and osteomyelitis 2.2 mAs, position check and foreign body search 1.25 mAs.

Neurotrophic factors cause activation of intracellular signaling pathways in Müller cells and other cells of the inner retina, but not photoreceptors

PURPOSE

Intravitreal injection of brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF), or basic fibroblast growth factor (FGF2) promotes survival of photoreceptors exposed to various types of insults, but it is not known if these survival-promoting effects occur by direct action of the factors on photoreceptors or indirectly through the activation of other cells. In this study, the authors have sought to address this issue by determining which cells in the retina show evidence of activated intracellular signaling pathways acutely and at longer time points after intravitreal injection of these agents.

METHODS

Retinas were removed from C57BL/6J mice at 1, 6, or 24 hours after intravitreal injection of 1 microg of human BDNF, rat CNTF, human FGF2, or human transforming growth factor-alpha (TGFalpha), and immunohistochemically stained for phosphorylated extracellular signal-regulated kinase (pERK), phosphorylated cAMP responsive element binding protein (pCREB), or c-fos. Retinal organ cultures were incubated with 10 ng/ml of BDNF, CNTF, FGF2, or TGFalpha for 10 or 30 minutes or 1, 3, or 6 hours and then immunohistochemically stained for pERK, pCREB, or c-fos.

RESULTS

Intravitreal injection of BDNF, CNTF, or FGF2 resulted in a rapid increase in pERK immunoreactivity in Müller cells and a rapid increase in c-fos immunoreactivity in Müller, amacrine, and ganglion cells. Immunoreactivity for pERK and c-fos returned to baseline in all retinal cells at 6 or 24 hours after injection, but there was increased staining for glial fibrillary acidic protein (GFAP) in Müller cells at these time points. At no time after injection was there any staining for pERK or c-fos in photoreceptors. Similarly, retinal explants treated with FGF2, BDNF, or CNTF showed increased staining for pCREB, pERK, and c-fos in cells of the inner retina, but not photoreceptors.

CONCLUSIONS

These data support the hypothesis that BDNF, CNTF, and FGF2 exert their effects on photoreceptors by acting indirectly through activation of Müller cells and perhaps other nonphotoreceptor cells.

Laser-assisted percutaneous endoscopic neurolysis

Endoscopic lysis of adhesive scar utilizing a steerable fiberoptic scope is currently being performed by a growing number of physicians. Various techniques and medications are presently being used to lyse epidural adhesions as a way of improving refractory lumbar radiculopathies. We present a case report discussing laser-assisted endoscopic lysis with radiographic images before and after laser-assisted neurolysis. We were able to demonstrate improvement in the filling of the nerve root with epidural contrast after the laser lysis of scar. This correlated with improvement in pain without neurologic deficit. The laser may represent a useful adjunct in the treatment of pain due to epidural fibrosis.

Cell death in age-related macular degeneration

The cellular and molecular mechanisms underlying the death of photoreceptors and other retinal cells in age-related macular degeneration (AMD) remain poorly understood. Some of the questions for which answers need to be sought, and which are explicitly or implicitly addressed in this article include: (1) how do patterns of cell death in AMD compare, qualitatively and quantitatively, with "normal" cell death in aging retinas, and with cell death in retinitis pigmentosa (RP) and its animal models; (2) is apoptosis involved in AMD; (3) is there any evidence that rods are necessary for cone survival; (4) if the answer is yes, is there evidence that rods produce one or more survival-promoting factor(s) that act directly on cones; (5) are the effects of rods upon cones exclusively mediated by diffusible factors, or do they also involve contact-mediated interactions; (6) is there any evidence that photoreceptors regulate the survival and/or function of RPE and Müller cells, as well as the interactions between these cells and cones; (7) are trophic factors and their receptors in the macula different from those in other parts of the retina; and (8) are toxic mechanisms involved in the onset and progression of cell death in AMD? Clear cut answers to most of these (and related) questions about cell death in AMD are not yet available. The goal of this article is to summarize discussion that should help in the formulation of suitable hypotheses, amenable to experimental analysis. To provide a platform for such discussion, we present an overview of progress made in recent years in the analysis of other retinal degenerations and of neuronal degenerations in other regions of the CNS. We conclude with an overview of concepts and speculation derived from our current research.

Intravenous lidocaine, amantadine, and placebo in the treatment of sciatica: a double-blind, randomized, controlled study

BACKGROUND AND OBJECTIVES

Sciatica is a neuropathic pain syndrome caused by compression and/or inflammation of spinal nerve roots by herniated disc material, and its treatment is therefore usually aimed at reducing compression and inflammation. Studies have shown that both systemic local anesthetics and N-methyl-D-aspartate (NMDA) receptor antagonists may produce analgesia in a variety of neuropathic pain syndromes. The present study evaluated the analgesic efficacy of i.v. infusions of the local anesthetic lidocaine, the NMDA receptor antagonist amantadine, and a placebo in sciatica.

METHODS

Thirty patients with sciatica, as confirmed by physical examination and imaging studies, were enrolled in a randomized, double-blind, three-arm crossover trial. Infusions of amantadine (2.5 mg/kg), lidocaine (5 mg/kg), and a placebo were administered over a 2-hour period, 2-7 days apart from each other. Spontaneous pain (visual analog scale) and evoked pain (straight leg raise) were measured every 30 minutes for 3 hours.

RESULTS

Lidocaine reduced spontaneous pain as compared with amantadine and with the placebo for all measurements and at a significant level at the 30 (P < .05), 120, and 180 (P < .01) minute time points. Maximal pain reduction from the baseline was 62 +/- 7% for lidocaine, 43 +/- 7% for amantadine, and 47 +/- 7% for the placebo. Straight leg raise test also significantly improved with lidocaine (from 30 to 37 degrees; P < .05), as compared to amantadine (34-36 degrees) and to the placebo (32-34 degrees). All three treatments were relatively well tolerated.

CONCLUSIONS

Intravenous lidocaine, rather than amantadine, reduces both spontaneous and evoked sciatic pain.

Varicella complicated by group A streptococcal sepsis and osteonecrosis

A 5-year-old boy presented with primary varicella zoster virus infection, group A streptococcal sepsis, toxic shock, and multisite osteonecrosis. An association between osteonecrosis and group A streptococcal sepsis has not been previously reported. Clinical recognition with supportive radiologic and pathologic findings are presented. Therapeutic guidelines are suggested.

Activin family members in the developing chick retina: expression patterns, protein distribution, and in vitro effects

We have investigated whether the activin family of growth factors is involved in the regulation of retinal cell differentiation. Immunocytochemistry and in situ hybridization have shown that activin/inhibin subunits alpha, betaA, and betaB; receptors II and IIB; follistatin; and a follistatin-like gene are expressed in different regions of the chick embryo retina in developmentally regulated patterns. When tested in dissociated retinal cultures, activin did not appear to affect cell survival or proliferation, but it exerted marked inhibitory effects on the differentiation of photoreceptors, while stimulating the differentiation of nonphotoreceptor neurons; both effects were concentration-dependent and follistatin-sensitive. The results are consistent with the possibility that activin family members play significant roles in the regulation of retinal development.

Comparison of immunogenicity of two hepatitis A vaccines--VAQTA and HAVRIX--in young adults

Two new hepatitis A vaccines have been developed, and their immunogenicity tested using different immunoassays. The present study was designed to compare the immunogenicity of these two hepatitis A virus (HAV) vaccines--VAQTA and HAVRIX--as determined by seroconversion rates and anti-HAV titers, and using the same immunoassay. Healthy volunteers (15-30 y), seronegative for anti-HAV, were randomized in an open single center study to four groups of 20-21 vaccinees each, to receive either a 25 U or a 50 U dose of VAQTA, or HAVRIX at 720 EU or 1440 EU/dose, administered at 0, 1 and 6 m or at 0 and 6 m, respectively. Four weeks after primary immunization, seroconversion rates were 100% for VAQTA and 95% for HAVRIX, following injection of 50 U or 1440 EU, respectively (p = NS) and anti-HAV GMTs were 40 and 37 mIU/ml for VAQTA and HAVRIX, respectively. At 6 months, prior to the booster dose, seroconversion rates were 100% for both vaccines, with anti-HAV GMTs of 111 and 70 mIU/ml for VAQTA and HAVRIX, respectively (P < 0.05). At month 7, four weeks after the only booster injection, using the two dose regimen, anti-HAV titers were 2212 and 1511 mIU/ml for VAQTA and HAVRIX, respectively (P < NS). Using three doses of 25 U/dose of VAQTA or 720 EU/dose of HAVRIX at 0, 1 and 6 m did not produce any clinically evaluable advantage over the two dose regimen for either vaccine. No significant adverse events were observed using either vaccine. In summary, both vaccines have similar immunogenicity demonstrated using identical immunoassays for evaluation. These results also confirm the outstanding immunogenicity of a single dose of either of the HAV vaccines and support their use in pre- and possibly postexposure prophylaxis against hepatitis A virus infection.

Comparison of immune reactivity and pharmacokinetics of two hepatitis B immune globulins in patients after liver transplantation

Hepatitis B virus (HBV) immune globulin (HBIg) administration will prevent HBV graft reinfection in HBV patients after orthotopic liver transplantation (OLT). However, the expenditure for such prophylaxis is extremely high ranging between $2,000 to $10,000 per month in various countries for an undefined period and presumably for life. As a consequence, there is a need for introduction of additional and less expensive modes of treatment. In a preliminary clinical trial a new HBIg preparation has been shown to induce longer lasting levels of circulating antibodies to hepatitis B surface antigen (anti-HBs) in patients after OLT compared with previous experience with conventional HBIg preparations. In the present study the pharmacokinetics of this new HBIg, OMRI-Hep-B, were studied and compared with a conventional, licensed preparation, Hepatect. Fifteen post-OLT patients (2-8 years post-OLT, 18-62 years of age, 6 men, 9 women) were treated intravenously with 49 doses of OMRI-Hep-B or Hepatect given at least once, alternately, at 10,000 to 14,000 units per injection ( approximately 130 IU/kg body weight). The new HBIg was well tolerated and no adverse effects were observed. Administration of OMRI-Hep-B was shown to induce high and long-lasting levels of circulating anti-HBs antibodies and greater areas under the curve (AUC) compared with the conventional preparation. Thus, anti-HBs half-life was 22 +/- 1.3 days for OMRI-Hep-B recipients and 13 +/- 1.3 days for Hepatect recipients (P <.001). Time to reach trough anti-HBs levels of 150 mIU/mL was significantly longer after administration of OMRI-Hep-B than after Hepatect (79 +/- 4.5 and 52 +/- 3.8 days, respectively; P <.001). In summary, the pharmacokinetic profile of the new HBIg, and in particular its prolonged elimination half-life, may reduce the cost of administration by approximately 30% and improve the quality of life of patients by extending the interval between repeated immune globulin injections.

Chronic pain in Holocaust survivors

There is limited research on the connection between the Holocaust and chronic pain, despite evidence suggesting that medical and psychological sequelae are common in survivors. The goals of this study were: (1) to define Holocaust survivors' (n = 33) chronic pain characteristics as manifested 50 years after the war, (2) to compare survivors with controls (n = 33) who did not experience World War II atrocities, and (3) to investigate the connection between past trauma and chronic pain. Data were collected through questionnaires that included a detailed medical and pain history, visual analog scale (VAS), McGill Pain Questionnaire (MPQ), Beck Depression Inventory (BDI), Symptom Check List-90 (SCL-90), and Pain Disability Index (PDI). A comparison of variables between the two groups was conducted using multivariate analysis of variance (MANOVA) and ANOVA, and canonical discriminant analysis. Results showed that Holocaust survivors reported higher pain levels (73 +/- 18 vs. 56 +/- 21; P < 0.005), more pain sites (4.5 6 2.8 vs. 2.7 6 1.4; P < 0.05), and significantly higher depression scores (17.6 +/- 8.4 vs. 9.2 +/- 4.6; P < 0.001); they tended to utilize more medical services (5.9 +/- 3.0 vs. 5.1 +/- 2.8). Nonetheless, survivors did not regard themselves more disabled as compared with controls. They reported a higher activity level as measured by walking distance capacity, and spent significantly fewer hours resting (4.3 +/- 3.6 vs. 7 +/- 4.6; P < 0.05). This paradoxical combination of high pain intensity, moderate to severe depression, and high activity level characterizes Holocaust survivors' chronic pain. It is conceivable that by remaining active Holocaust survivors fight back their pain, distress, and depression. These findings suggest that Holocaust atrocities affect survivors' chronic pain even years later.

Developmental neuronal death is not a universal phenomenon among cell types in the chick embryo retina

The goal of this study was to investigate whether all the cell types present in the chick embryo retina undergo developmental neuronal death. Apoptosis was investigated in retinal sections at different developmental stages, processed either with propidium iodide, which stains pyknotic nuclei intensely, or with terminal transferase-mediated deoxyuridine triphosphate (d-UTP)-biotin nick-end labeling (TUNEL). Internucleosomal DNA fragmentation was investigated in tissue extracts by agarose gel electrophoresis. TUNEL-positive (T+) cells and pyknotic nuclei were first detectable in the ganglion cell layer (GCL) around embryonic day (ED) 8 and peaked at ED 10. In the inner nuclear layer (INL), T+ and pyknotic cells first appeared on ED 8, reached maximum frequency on ED 11, and were largely absent after ED 14. DNA ladders were observed at all the stages, when T+ and pyknotic cells were abundant, but not on ED 4, when only scattered dead cells were observed histologically. Dying cells were virtually never detected in the outer nuclear layer (ONL) from ED 4 to postnatal day 2. After unilateral midbrain ablation on ED 5, there was a striking increase in the number of pyknotic and T+ cells in both the GCL and in the INL of the contralateral eye but not in the ONL. The absence of apoptotic cell death in the ONL during normal development and after tectal ablation shows that developmental death is not universal among the various cell populations present in the chick embryo retina and raises questions regarding mechanisms controlling both photoreceptor survival and the matching of pre- and postsynaptic elements in the outer plexiform layer of this species.

Comparison of treatments of persistent conduct problems in primary school children: a preliminary evaluation of a modified cognitive-behavioural approach

OBJECTIVE

Treatment for persistent conduct problems in primary school children was developed using a modification of cognitive-behavioural therapy (MCBT). Its effectiveness was evaluated by comparing it with conjoint family therapy (FT) and eclectic therapy (ET).

METHOD

Children with persistent conduct problems were randomly assigned to one of three treatment groups. They were assessed prior to treatment and then 6 months after. Measures included symptoms of the child; parents' mental health; stress of parenting; family functioning; and parental relationship. In addition, parents' and children's perception of the therapy were assessed and a treatment record was developed to track the treatment process.

RESULTS

Thirty-two children were recruited for the study. No statistically significant differences were found in terms of effectiveness between the three groups. In terms of parents' perception of the therapy, there was no difference on the perception of the qualities of the therapists, but on the perception of therapy MCBT was considered to be higher in cognitive-behavioural orientation.

CONCLUSION

Further research using a larger sample is required to evaluate MCBT. The study supports the idea that controlled treatment studies can be carried out within busy mental health services.

The NMDA receptor antagonist amantadine reduces surgical neuropathic pain in cancer patients: a double blind, randomized, placebo controlled trial

Neuropathic pain is often severe, persistent, and responds poorly to analgesic medications. Recent evidence suggests that N-methyl-D-aspartate (NMDA) receptor antagonists may be effective in the treatment of neuropathic pain. The present trial was designed to test the efficacy of acute administration of the NMDA receptor antagonist amantadine in relieving surgical neuropathic pain in patients with cancer. The study sample consisted of 15 cancer patients with the diagnosis of surgical neuropathic pain. Two 500 ml infusions of either 200 mg amantadine or placebo were administered over a 3 h period, in a randomized order, 1 week apart from each other. Spontaneous and evoked pain were measured for 48 h before treatment, during treatment, and for 48 h following treatment. An average pain reduction of 85% was recorded at the end of amantadine infusion vs. 45% following placebo administration. The difference in pain relief between the two treatments was statistically significant (P = 0.009). Mean pain intensity remained significantly lower during the 48 h following amantadine treatment as compared with the 48 h prior to treatment (31% reduction; P = 0.006), whereas no such effect was found with the placebo (6% reduction; P = 0.40). Amantadine, but not the placebo, also reduced 'wind up' like pain (caused by repeated pinpricking) in four patients. We conclude that amantadine infusion is a safe and effective acute treatment for surgical neuropathic pain in cancer patients. Further trials with long-term oral or parenteral amantadine treatment should be conducted.

Preschool behaviour problems in a multicultural Australian urban area

OBJECTIVE

This paper reports on a survey of behaviour problems in a sample of 4-year-old preschoolers from the western suburbs of metropolitan Melbourne. This region consists of a diverse multicultural population and families from lower socio-economic status (SES) backgrounds.

METHODOLOGY

Nineteen preschools participated in the study and information was obtained for 743 preschool children (Refer to MS) age=4.7 years). Parents were asked to complete the Preschool Behaviour Questionnaire (PBQ) and additional questions referring to demographic and family information. Teachers were also asked to complete the PBQ on each of the children. Three factors were extracted from the PBQ (anxious-fearful, hostile-aggressive, hyperactive), and also a combined externalising behaviours factor.

RESULTS AND CONCLUSIONS

Findings indicated lower levels of behaviour problems in this sample compared to that of other Australian studies. Boys showed higher rates of externalising behaviour problems than girls. The relationships between behaviour problems and language difficulties, ethnicity, and socio-economic status are discussed.

Identification of two rds/peripherin homologs in the chick retina

PURPOSE

To identify possible homologs of mammalian rds/peripherin in chick photoreceptors.

METHODS

An embryonic day-15 chick retinal library was screened by polymerase chain reaction with degenerate oligonucleotide primers derived from conserved segments of the mammalian retinal degeneration slow (rds) mRNA. The resultant amplification products were used to isolate cDNAs, containing complete coding regions. These clones were studied by nucleotide sequence, Northern blot, and in situ hybridization analyses.

RESULTS

Two new homologs of rds/peripherin were discovered: crds1 and crds2. The predicted crds1 protein is 78%, and the predicted crds2 protein is 54%, identical to mammalian rds/peripherin. The crds1 mRNA is an abundant 4.4-kb species present in photoreceptors. The crds2 mRNA is of similar size but is much rarer. No homologs of rom1 were identified in our screen. Developmentally, the crds1 mRNAs were first detectable at embryonic day 18.

CONCLUSIONS

Crds1 likely represents the chick ortholog of mammalian rds/peripherin, whereas crds2 is a more distant homolog. Both share an elongated C-terminal domain, an unusual feature compared with other members of the rds family.

Neurological complaints after unsuccessful spinal anaesthesia as a manifestation of incipient syringomyelia

The medical literature sometimes reports neurological complications after spinal or epidural anaesthesia. In a few cases, the onset of symptoms can be a sign of a pre-existing disease without a primary connection with regional anaesthesia. In the following case report, the patient complained of paraesthesias in both legs after a failed spinal anaesthesia, even though the needle had been placed intrathecally. Only neurological examination and nuclear magnetic resonance imaging revealed the presence of syringomyelia.

Suppression of human hepatoma in mice through adoptive transfer of immunity to the hepatitis B surface antigen

BACKGROUND/AIMS

Adoptive transfer of immunity against hepatitis B surface antigen (HBsAg) has previously been shown to occur in mice and humans through transplantation of bone marrow cells from donors immunized against HBsAg (anti-HBs) to non-immune recipients. In the present study we evaluated the effect of adoptive transfer of immunity to HBsAg on the growth of HbsAg-secreting hepatocellular carcinoma (HCC) xenografts in athymic mice.

METHODS

Immunocompetent mice were immunized with recombinant HBsAg. Bone marrow cells from anti-HBs+ mice were injected intravenously to irradiated athymic Balb/c mice which had been previously transplanted subcutaneously with Hep3B human hepatoma cells. Treatment groups included mice receiving bone marrow transplantation from HBV-immunized (anti-HBs positive) and non-immunized (anti-HBs negative) donors.

RESULTS

At 9 weeks post bone marrow transplantation, tumor volume and serum alpha-fetoprotein levels in athymic mice receiving HBV-immune bone marrow cells were 11.5 mm3 and 363 ng/ml, respectively, as compared to 1579 mm3 and 19,000 ng/ml, in recipients of non-immune bone marrow transplantation (p<0.005). T-cell depletion of antiHBs+ immune bone marrow prior to transplantation decreased the anti-tumor effect but did not abolish it. A mild nonspecific, bone marrow-derived, graft versus tumor effect was observed in mice transplanted with human hepatoma cells that do not express HBsAg.

CONCLUSIONS

Adoptive transfer of immunity to HBV facilitates suppression of experimental human HCC expressing HBsAg. This effect is the result of a combination of specific anti-viral surface antigen effect and a nonspecific graft versus tumor effect.

Pax-6, Prox 1, and Chx10 homeobox gene expression correlates with phenotypic fate of retinal precursor cells

PURPOSE

To study the expression patterns of the homeobox genes Pax-6, Prox 1, and Chx10 during chick retinal development in vivo and in vitro.

METHODS

Sections of paraformaldehyde-fixed, paraffin-embedded eyes were obtained at a range of developmental stages. In situ hybridization was carried out on tissue sections using digoxigenin-labeled sense and antisense RNA probes that recognize chicken Pax-6 and Prox 1 (whose sequences were already available), and chicken Chx10 (which was cloned and sequenced as part of this study). Selected developmental stages were also studied by immunocytochemistry with antibodies against Pax-6 and Prox 1, and by Northern blot analysis using 32P-labeled probes.

RESULTS

Until embryonic day (ED) 5, in situ hybridization shows widespread, diffuse distribution of all three genes. Between ED 6 and ED 8, however, they acquire distinct, topographically specific patterns of expression. The Prox 1 signal is predominantly expressed in the prospective horizontal cell layer of the neuroepithelium, decreases vitreally, and is absent from ganglion cells and the prospective photoreceptor layer. Pax-6 is strongly expressed only in the prospective ganglion-cell and amacrine-cell regions at the same stages, and is not detected in prospective photoreceptors. Chx10 expression becomes concentrated in the future bipolar-cell region of the inner nuclear layer. Similar patterns are maintained by ED 15 through ED 18, after cell differentiation has taken place. Pax-6 and Prox 1 immunoreactive materials showed nuclear localization and a pattern of laminar distribution equivalent to that seen by in situ hybridization.

CONCLUSIONS

These results suggest that the differentiated fate of retinal precursor cells may be influenced by Pax-6, Prox 1, or Chx10, this hypothesis is now being tested using dissociated chick embryo retinal cell cultures.

The bZIP transcription factor Nrl stimulates rhodopsin promoter activity in primary retinal cell cultures

In vitro DNA binding assays and transient transfection analysis with monkey kidney cells have implicated Nrl, a member of the Maf-Nrl subfamily of bZIP transcription factors, and the Nrl response element (NRE) in the regulation of rhodopsin expression. We have now further explored the role of the NRE and surrounding promoter elements. Using the yeast one-hybrid screen with integrated NRE and flanking DNA as bait, the predominant clone obtained was bovine Nrl. Recovery of truncated clones in the screen demonstrated that the carboxyl-terminal half of Nrl, which contains the basic and leucine zipper domains, is sufficient for DNA binding. To functionally dissect the rhodopsin promoter, transient expression studies with primary chick retinal cell cultures were performed. Deletion and mutation analyses identified two positive regulatory sequences: one between -40 and -84 base pairs (bp) and another between -84 and -130 bp. Activity of the -40 to -84 region was shown to be largely due to the NRE. On co-transfection with an NRL expression vector, there were 3-5-fold increases in the activity of rhodopsin promoter constructs containing an intact NRE but little or no effect with rhodopsin promoters containing a mutated or deleted NRE. Nrl was more effective than the related bZIP proteins, c-Fos and c-Jun, in stimulating rhodopsin promoter activity. The -84- to -130-bp region acted synergistically with the NRE to enhance both the level of basal expression and the degree of Nrl-mediated trans-activation. These studies support Nrl as a regulator of rhodopsin expression in vivo, identify an additional regulatory region just upstream of the NRE, and demonstrate the utility of primary retinal cell cultures for characterizing both the cis-acting response elements and trans-acting factors that regulate photoreceptor gene expression.

Child Behaviour Checklist classification of behaviour disorder

OBJECTIVE

The aim of this study was to determine the applicability of the published clinical cut-off scores of the Child Behaviour Checklist (CBCL) for the classification of behaviour disorders.

METHODOLOGY

Child Behaviour Checklists were obtained for 1342 subjects newly referred to the six major mental health centres in Melbourne. The normative community sample of 1002 7-, 12- and 15-year-olds was drawn from a school-based asthma prevalence study.

RESULTS

The mean total problem T-score for the children referred to mental health centres was 67 and was above the clinical range for all age groups. Using referral to psychiatric services as the gold standard, the sensitivity and specificity of the CBCL using a cut-off of > or = 60, was 77.4 and 83.2%, respectively. This compares favourably with the sensitivity of 68% and specificity of 82% for the American sample. Using a cut-off score of > or = 63, the sensitivity was 70.5% and the specificity was 88.6%. The referred and community samples differed with respect to socio-economic status, family structure and mothers' level of education. Fifty-two per cent of the clinically referred children lived with both parents, compared with 89% of the community sample.

CONCLUSIONS

While there are some limitations to this study in terms of both the clinic and community sample, support is provided for the usefulness and applicability of the recommended CBCL cut-off scores in an Australian population.

Psychosocial and family functioning in children with insulin-dependent diabetes at diagnosis and one year later

Examined the initial impact and subsequent adjustment to the diagnosis of insulin-dependent diabetes mellitus (IDDM). Children between 1 and 14 years of age and their families were assessed several weeks after diagnosis and again a year later using standardized measures of child behavior, parental mental health, and family functioning. Immediately after diagnosis, the children and both parents exhibited mild symptoms of psychological distress but these had largely resolved at 12-month follow-up. The impact of IDDM diagnosis on family functioning varied with informant, SES, and the age of the child, with an overall tendency for families to become less flexible over the year. Findings suggest that most children and their parents exhibit satisfactory individual adjustment after a period of initial stress but family functioning is affected in complex ways. Serial follow-up of the cohort is planned to establish whether the current findings are predictive of longer term outcome.

Correlations between terminal mitosis and differentiated fate of retinal precursor cells in vivo and in vitro: analysis with the "window-labeling" technique

We have investigated with high resolution the timing of retinal precursor cell commitment to specific differentiated fates, using an in ovo modification of the in vitro "window-labeling" technique (A. M. Repka and R. Adler, J. Histochem. Cytochem. 40, 947-953, 1992a). The method involves an initial injection of tritiated thymidine into chick embryos, followed a specific number of hours later by an injection of bromodeoxyuridine (BrDU); cells born during this period are identified by being labeled with thymidine but not with BrDU. We used this method to determine, in a narrow region adjacent to the choroid fissure, the fate of cells born during defined 5-hr intervals between Embryonic Days (ED) 4-8. All the cohorts gave rise to heterogenous differentiated populations, indicating that time of cell birth is not a major cell fate determinant. A progressive restriction in the developmental potential of precursor cells, however, was suggested by the observed decrease in the number of different populations generated during each 5-hr period from ED 4 to 8, and supported also by dissociated cell culture experiments investigating the fate of cells born at different developmental stages. Microenvironmental influences were tested in vitro using cells windowed-labeled in ovo for 5 hr on ED 5. After spending at least 72 hr within the retina before their isolation for culture, these cells mimicked their in vivo fate, giving rise predominantly to nonphotoreceptor neurons; a completely different behavior was observed when the cells were isolated after shorter exposures to the retinal microenvironment, when they gave rise predominantly to photoreceptors. Together with data demonstrating that differential cell death cannot account for these results, our results are consistent with the hypothesis that cell fate determination occurs after the time of terminal mitosis.