Failure to prolyl hydroxylate hypoxia-inducible factor alpha phenocopies VHL inactivation in vivo.

Many functions have been assigned to the von Hippel-Lindau tumor suppressor gene product (pVHL), including targeting the alpha subunits of the heterodimeric transcription factor HIF (hypoxia-inducible factor) for destruction. The binding of pVHL to HIFalpha requires that HIFalpha be hydroxylated on one of two prolyl residues. We introduced HIF1alpha and HIF2alpha variants that cannot be hydroxylated on these sites into the ubiquitously expressed ROSA26 locus along with a Lox-stop-Lox cassette that renders their expression Cre-dependent. Expression of the HIF2alpha variant in the skin and liver induced changes that were highly similar to those seen when pVHL is lost in these organs. Dual expression of the HIF1alpha and HIF2alpha variants in liver, however, more closely phenocopied the changes seen after pVHL inactivation than did the HIF2alpha variant alone. Moreover, gene expression profiling confirmed that the genes regulated by HIF1alpha and HIF2alpha in the liver are overlapping but non-identical. Therefore, the pathological changes caused by pVHL inactivation in skin and liver are due largely to dysregulation of HIF target genes.

The architecture of active zone material at the frog's neuromuscular junction.

Active zone material at the nervous system's synapses is situated next to synaptic vesicles that are docked at the presynaptic plasma membrane, and calcium channels that are anchored in the membrane. Here we use electron microscope tomography to show the arrangement and associations of structural components of this compact organelle at a model synapse, the frog's neuromuscular junction. Our findings indicate that the active zone material helps to dock the vesicles and anchor the channels, and that its architecture provides both a particular spatial relationship and a structural linkage between them. The structural linkage may include proteins that mediate the calcium-triggered exocytosis of neurotransmitter by the synaptic vesicles during synaptic transmission.

Reference group data for the Reitan-Indiana Neuropsychological Test Battery for Young Children.

This study presents a data set for a reference group on the Reitan-Indiana Neuropsychological Test Battery for Young Children. The data set is based on a sample of 224 children, ages 5 to 8 years, referred to a special services cooperative for academic or behavioral concerns during the years 1980 through 1993. Data are presented in terms of sample size, means, standard deviations, diagnostic classifications, and population characteristics. Previously published data sets are reviewed in comparison to this newly acquired data set. Potential advantages of this data set include the larger sample, contemporary data collection, and a sample drawn from a United States school-referred population.

Prolonged cyclooxygenase-2 induction in neurons and glia following traumatic brain injury in the rat.

Cyclooxygenase-2 (COX2) is a primary inflammatory mediator that converts arachidonic acid into precursors of vasoactive prostaglandins, producing reactive oxygen species in the process. Under normal conditions COX2 is not detectable, except at low abundance in the brain. This study demonstrates a distinctive pattern of COX2 increases in the brain over time following traumatic brain injury (TBI). Quantitative lysate ribonuclease protection assays indicate acute and sustained increases in COX2 mRNA in two rat models of TBI. In the lateral fluid percussion model, COX2 mRNA is significantly elevated (>twofold, p < 0.05, Dunnett) at 1 day postinjury in the injured cortex and bilaterally in the hippocampus, compared to sham-injured controls. In the lateral cortical impact model (LCI), COX2 mRNA peaks around 6 h postinjury in the ipsilateral cerebral cortex (fivefold induction, p < 0.05, Dunnett) and in the ipsilateral and contralateral hippocampus (two- and six-fold induction, respectively, p < 0.05, Dunnett). Increases are sustained out to 3 days postinjury in the injured cortex in both models. Further analyses use the LCI model to evaluate COX2 induction. Immunoblot analyses confirm increased levels of COX2 protein in the cortex and hippocampus. Profound increases in COX2 protein are observed in the cortex at 1-3 days, that return to sham levels by 7 days postinjury (p < 0.05, Dunnett). The cellular pattern of COX2 induction following TBI has been characterized using immunohistochemistry. COX2-immunoreactivity (-ir) rises acutely (cell numbers and intensity) and remains elevated for several days following TBI. Increases in COX2-ir colocalize with neurons (MAP2-ir) and glia (GFAP-ir). Increases in COX2-ir are observed in cerebral cortex and hippocampus, ipsilateral and contralateral to injury as early as 2 h postinjury. Neurons in the ipsilateral parietal, perirhinal and piriform cortex become intensely COX2-ir from 2 h to at least 3 days postinjury. In agreement with the mRNA and immunoblot results, COX2-ir appears greatest in the contralateral hippocampus. Hippocampal COX2-ir progresses from the pyramidal cell layer of the CA1 and CA2 region at 2 h, to the CA3 pyramidal cells and dentate polymorphic and granule cell layers by 24 h postinjury. These increases are distinct from those observed following inflammatory challenge, and correspond to brain areas previously identified with the neurological and cognitive deficits associated with TBI. While COX2 induction following TBI may result in selective beneficial responses, chronic COX2 production may contribute to free radical mediated cellular damage, vascular dysfunction, and alterations in cellular metabolism. These may cause secondary injuries to the brain that promote neuropathology and worsen behavioral outcome.

Automatic acquisition of fiducial markers and alignment of images in tilt series for electron tomography.

Three-dimensional reconstruction of a section of biological tissue by electron tomography requires precise alignment of a series of two-dimensional images of the section made at numerous successive tilt angles. Gold beads on or in the section serve as fiducial markers. A scheme is described that automatically detects the position of these markers and indexes them from image to image. The resulting set of position vectors are arranged in a matrix representation of the tilt geometry and, by inversion, alignment information is obtained. The scheme is convenient, requires little operator time and provides an accuracy of < 2 pixels RMS. A tilt series of 60-70 images can be aligned in approximately 30 min on any modern desktop computer.

Diabetes risk factors in low-income Mexican-American children.

OBJECTIVE: To learn if Mexican-American children from low income neighborhoods have excess diabetes risk factors. RESEARCH DESIGN AND METHODS: The study involved 173 Mexican-American children aged 9 years. This is the age before type 2 diabetes usually develops in youths and where the disparity in body fat between Mexican-American and non-Hispanic white children is evident. The study also targets poor children because diabetes and being overweight are more common in Mexican-American adults from a lower than from a higher socioeconomic status. The diabetes risk factors measured were percent body fat, dietary fat intake, daily fruit and vegetable intake, and physical fitness. Body fat was measured by bioelectric impedance, dietary intake was measured by three 24-h dietary recalls, and physical fitness was measured by a modified Harvard step test. RESULTS: According to self-reported dietary recalls, Mexican-American children ate higher than recommended fat servings and had higher percent energy from fat and saturated fat. On the other hand, their reported daily fruit and vegetable intake was half of that recommended by national dietary guidelines. A large percentage of these children were at unacceptable physical fitness levels. Percent body fat was higher in these Mexican-American children than that reported for non-Hispanic white children. Finally, 60% of the children had a first- or second-degree relative with diabetes. CONCLUSIONS: Because diabetes is highly prevalent in Mexican-American adults, type 2 diabetes in increasing in Mexican-American youths, and diabetes risk factors are more common in Mexican-American children, a prudent measure would be to explore early-age diabetes risk factor prevention programs in this population.

Arithmetic disabilities and ADD subtypes: implications for DSM-IV.

This study investigated whether specific academic deficits were associated with attention-deficit disorder (ADD) subtypes. Twenty students (ages 8-12) with attention-deficit disorder with hyperactivity (ADD/H) were compared to 20 students with attention-deficit disorder without hyperactivity (ADD/noH). Group differences were compared using a MANCOVA, and paired t tests were used to compare within-group differences. Dependent variables for the within-group differences were four achievement subtest scores from the Woodcock-Johnson Psycho-Educational Battery-Revised: Letter-Word Identification, Passage Comprehension, Calculation, and Applied Problems. Consistent with much of the previous research, no significant between-group differences were found on the achievement measures. Significant differences did, however, appear in the six within-group comparisons, all involving lower performance on the Math Calculations subtest. For students with ADD/H, only one comparison (with Math Applied Problems) reached significance. Students with ADD/noH, however, had significantly lower scores on the Calculation subtest compared to all of the other achievement subtests. These results provided additional support for the hypothesis that inattention exerts a specific and deleterious effect on the acquisition of arithmetic computation skills. These findings have important implications for the diagnosis and treatment of ADHD as conceptualized in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV; American Psychiatric Association, 1994), because they suggest that students with ADHD-Predominantly Inattentive Type may be at increased risk for arithmetic calculation deficits.

Dissection of active zones at the neuromuscular junction by EM tomography.

We used EM tomography to examine the fine structure of the apparently amorphous electron dense material that is seen at active zones of axon terminals when viewed by conventional 2D electron microscopy. Serial 1-nm optical slices from 3D reconstructions of individual thin tissue sections reveal that the material is composed of an interconnecting network of elongate components directly linked to synaptic vesicles and the presynaptic membrane. Each vesicle at the active zone that lies adjacent to the presynaptic plasma membrane has several such connections. Information provided by reconstruction data may be useful in generating experiments aimed at understanding the mechanisms involved in the docking of synaptic vesicles and their exocytosis during synaptic transmission.

Behavioral and emotional problems of students with learning disabilities, serious emotional disturbance, or both conditions.

This study investigates the behavioral and emotional problems of children with learning disabilities (LD), serious emotional disturbance (SED), and LD/SED, using the Teacher Report Form (TRF) and Child Behavior Checklist (CBCL). The sample consisted of 217 students with LD, 72 with SED, and 68 with SED/LD, ages 6 to 18 (mean age = 11.5). The students with SED were rated more impaired than the students with LD on all TRF scales except Attention Problems, and on three of the eight CBCL syndrome scales. The children with LD differed from those with SED mainly in terms of severity of problems, not with respect to type of problem. It is concluded that students with co-morbid LD and SED are underidentified and underserved in special education systems.

Academic underachievement in ADHD subtypes.

Although a relationship between attention-deficit/hyperactivity disorder (ADHD) and academic underachievement has been widely reported, the nature of this relationship has not been specified. The present investigation addresses this relationship directly by comparing 24 students (20 males and 4 females) with ADHD and 20 students (15 males and 5 females) with attention-deficit disorder without hyperactivity (ADD/noH) referred to a university-based diagnostic clinic for comprehensive neuropsychological assessment. The students ranged in age from 6 years 0 months to 12 years 10 months. Consistent with previous reports, this study found that math achievement test scores for students with ADD/noH were significantly lower than those for students with ADHD. These findings support previous research suggesting the ADD/noH may represent a distinct ADD subtype. It is hypothesized that inattention interferes with students' ability to master abstract symbol systems, especially in the acquisition of basic arithmetic skills in the primary grades.

Use of the long vs short form of the speech sounds perception test in a school-age population.

A sample of 645 school-age children, ages 9 to 14 years, were administered independent forms of the Speech Sounds Perception Test for older children. 328 subjects took the complete test (SSPT-60) and 317 were administered only the first 30 items (SSPT-30). Comparison of mean errors indicated that significantly more errors were made by subjects given the SSPT-30. Decisions regarding the use of each form for school-age children are discussed.

How to improve allocation of support service costs.

Better accounting for support service costs at outpatient facilities involves distinguishing between fixed and variable expenses, then creating separate budgets for them. To simplify this step, financial managers can create a surrogate, such as the number of patient visits, to represent service activity. Once this is completed, separated costs are allocated by using criteria that recognize short-term and long-term service use.

Physician/school teacher collaboration. Some practical considerations.

Physician/school teacher collaboration is crucial if exceptional students are to receive appropriate educational services mandated by Public Law 94-142 and Public Law 99-457. There is little in the professional literature to guide physicians who may be interested in working more closely with school personnel. The present article provides specific suggestions and recommendations to private practitioners for initiating and managing interprofessional collaboration with school personnel.

Epilepsy and education: the pediatrician's expanding role.

School systems, teachers, health systems, and physicians are striving to assist students to reach their full potential. Physicians have an understanding of seizures and medications that should be shared with teachers. In turn, teachers know what parts of students' learning seem to be affected by their epilepsy; they also work with students every day and this gives them a unique perspective of changes in the patient's status. Epilepsy can profoundly affect the student-patient, the school, and the home. Pediatricians are in the unique position to share medical information with teachers and parents. By sharing this information, physicians encourage collaboration. Increased collaboration, in turn, helps to reduce the myths and fears surrounding epilepsy. It provides teachers with the information they use to plan instructional programs, and it improves physicians' decisions regarding diagnosis and treatment. Physician/teacher collaboration is generally advocated for patients-students in the "devastated" and the "compromised" groups. Collaboration is not necessary in patients without problems and it is probably preferable not to risk stigmatizing otherwise intact children by attaching the label "epilepsy" to them. When collaboration is indicated, teachers will need some way of organizing information about students' seizure, educational, medical, and psychosocial background. The appendix contains a list of questions grouped according to these categories. If teachers can answer these questions they will be well on the way to resolving the problems confronting the student with epilepsy. It is hoped that physicians will be available and willing to assist teachers and that teachers will seek their assistance.

Medical and educational literature on physician/teacher collaboration.

Recent changes in the education of exceptional children are placing new demands on physicians and teachers to work together. This article reviews the published educational and medical literature on physician/teacher collaboration. Articles from both fields contend that collaboration is necessary, desirable, and possible. As expected, all articles favor increased collaboration, however, specific guidelines to improve collaboration are surprisingly scarce. Suggestions to improve collaboration are provided.

Improving physician/teacher collaboration.

This paper describes a three-phase project designed to improve physician/teacher collaboration with exceptional school children. In phase 1, the school district's 54 special education personnel completed a 24-item questionnaire designed to identify communication and role-expectancy problems. Phase 2 consisted of a series of workshops in which physicians explained their evaluations and and treatments of exceptional children. In phase 3 a collaboration model linking the school district and a university-based medical center was developed and implemented. Questionnaire data, the collaboration model, and suggestions for other models are presented.

The prevalence of calcified upper urinary tract stone disease in a random population--Cumbernauld Health Survey.

It is difficult to obtain the true prevalence of stone disease in community. A proper random sample of a population has been studied and a figure of 3.83% of calcified stones have been found in 2,000 subjects. The significance of biochemical, bacteriological, skeletal and other surgical abnormalities is discussed. It is now possible to study individual groups within the population with respect to stone disease.