BDNF regulation under GFAP promoter provides engineered astrocytes as a new approach for long-term protection in Huntington's disease

Brain-derived neurotrophic factor (BDNF) is the main candidate for neuroprotective therapeutic strategies for Huntington's disease. However, the administration system and the control over the dosage are still important problems to be solved. Here we generated transgenic mice overexpressing BDNF under the promoter of the glial fibrillary acidic protein (GFAP) (pGFAP-BDNF mice). These mice are viable and have a normal phenotype. However, intrastriatal administration of quinolinate increased the number of reactive astrocytes and enhanced the release of BDNF in pGFAP-BDNF mice compared with wild-type mice. Coincidentally, pGFAP-BDNF mice are more resistant to quinolinate than wild-type mice, suggesting a protective effect of astrocyte-derived BDNF. To verify this, we next cultured astrocytes from pGFAP-BDNF and wild-type mice for grafting. Wild-type and pGFAP-BDNF-derived astrocytes behave similarly in nonlesioned mice. However, pGFAP-BDNF-derived astrocytes showed higher levels of BDNF and larger neuroprotective effects than the wild-type ones when quinolinate was injected 30 days after grafting. Interestingly, mice grafted with pGFAP-BDNF astrocytes showed important and sustained behavioral improvements over time after quinolinate administration as compared with mice grafted with wild-type astrocytes. These findings show that astrocytes engineered to release BDNF can constitute a therapeutic approach for Huntington's disease.

Localized perineal cutaneous nodules: a case of recurrent systemic anaplastic large-cell lymphoma

We report an unusual case of localized cutaneous nodules heralding the recurrence of systemic CD30+ anaplastic large-cell lymphoma (ALCL). A 47-year-old woman developed numerous violaceous nodules in the perineal and upper thigh area 3 years after multimodal treatment and complete remission of primary anaplastic large-cell CD30+ lymphoma. Using immunohistochemical and T-cell gene rearrangement analysis, a recurrence of her anaplastic large-cell lymphoma was diagnosed.

Targeted transgenesis at the HPRT locus: an efficient strategy to achieve tightly controlled in vivo conditional expression with the tet system

The tet-inducible system has been widely used to achieve conditional gene expression in genetically modified mice. To alleviate the frequent difficulties associated with recovery of relevant transgenic founders, we tested whether a controlled strategy of transgenesis would support reliable cell-specific, doxycycline (Dox)-controlled transgene expression in vivo. Taking advantage of the potent hypoxanthine-aminopterin-thymidine selection strategy and an embryonic stem (ES) cell line supporting efficient germ-line transmission, we used hypoxanthine phosphoribosyltransferase ( HPRT) targeting to insert a single copy tet-inducible construct designed to allow both glucocorticoid receptor (GR) and β-galactosidase (β-Gal) expression. Conditional, Dox-dependent GR and β-Gal expression was evidenced in targeted ES cells. Breeding ES-derived single copy transgenic mice with mice bearing appropriate tet transactivators resulted in β-Gal expression both qualitatively and quantitatively similar to that observed in mice with random integration of the same construct. Interestingly, GR expression in mice was dependent on transgene orientation in the HPRT locus while embryonic stem cell expression was not. Thus, a conditional construct inserted in single copy and in predetermined orientation at the HPRT locus demonstrated a Dox-dependent gene expression phenotype in adult mice suggesting that controlled insertion of tet-inducible constructs at the HPRT locus can provide an efficient alternative strategy to reproducibly generate animal models with tetracycline-induced transgene expression.

Acute toxicity testing in cultures of mouse neuroblastoma cells

Cultured mouse neuroblastoma cells (C1300) may be used as models for nerve cells since they have a number of properties in common with their normal counterparts in vivo. In order to test the possibility of using C1300 cells as alternative to experimental animals when testing for acute toxicity, cells (clone 41A3) were exposed to a number of common chemicals (CH3HgCl, CdCl2,HgCl2 ppDDT, n-butanol, benzene, dioxan, n-propanol, aceton and t-butanol). The toxic effect was quantified by measuring the degree of cell detachment in the cultures. The concentrations of chemicals that caused 25% of the total cell number to detach (TD25) were used for comparison with LD50 values. In spite of the very simplified situation in culture, where the toxicity of a substance is little or not at all influenced by factors like penetration, storage, metabolism and excretion a good correlation (corr. coeff. 0,98) was obtained between TD25 values and LD50 values. Good correlations between in vitro and in vivo tests have also been reported by others. One possible explanation to these findings could be simplified in vivo toxicokinetics of these substances when tested in high doses for general effects like animal death. If so, simple in vitro tests may be used for predicting acute toxicity of certain groups of substances.

Differential gene expression during terminal erythroid differentiation

Terminal erythroid differentiation in mammals is the process whereby nucleated precursor cells accumulate erythroid-specific proteins such as hemoglobin, undergo extensive cellular and nuclear remodeling, and ultimately shed their nuclei to form reticulocytes, which then become mature erythrocytes in the circulation. Little is known about the mechanisms that enable erythroblasts to undergo such a transformation. We hypothesized that genes involved in these mechanisms were likely expressed at restricted times during the differentiation process and used differential display reverse transcriptase polymerase chain reaction as a first step in identifying such genes. We identified three differentially expressed cDNAs that we termed late erythroblast (LEB) 1-3. None of these cDNAs were previously identified as being expressed in erythroblasts and their patterns of expression indicated they are likely to be involved in the differentiation process. LEB-1 cDNA was derived from the gene A330102K04Rik (approved gene symbol Apoll1), and shares homology with members of the apolipoprotein L family in humans. LEB-3 cDNA was derived from the novel gene D930015E06Rik, that has no known function. LEB-2 cDNA was derived from the gene ranBP16 (approved gene symbol Xpo7), a nuclear exportin. D930015E06Rik mRNA is also strongly expressed in the testis and was localized to a region of the seminiferous tubule where secondary spermatocytes and early spermatids are found, suggesting a role for D930015E06Rik in spermatogenesis as well as terminal erythroid differentiation. We have thus identified three genes not previously described as being expressed in erythroblasts that could be relevant in elucidating mechanisms involved in terminal erythroid differentiation.

Early Functional Loading of Brånemark Dental Implants: 5-Year Clinical Follow-up Study

BACKGROUND

Short-term clinical studies have indicated the possibility of one-stage surgery and early loading of machined titanium implants. However, long-term data comparing the outcome to the conventional two-stage technique are missing.

PURPOSE

A clinical and radiographic study was performed to compare the outcome of oral rehabilitation of the edentulous mandible by fixed suprastructures connected to implants installed according to either (1) a one-stage surgical procedure and early loading (experimental group--EG) or (2) the original two-stage concept (reference group--RG). The EG and RG comprised 16 and 11 subjects, respectively.

MATERIALS AND METHODS

The following specific inclusion criterion were adopted: (1) all patients had to consider themselves to be in good general health, (2) the amount of bone had to enable the installation of five to six, at least 10-mm long fixtures (Mk II fixtures; Nobel Biocare AB, Göteborg, Sweden) between the mental foramina, and (3) the patients had to be available for the follow-up and maintenance program. A total of 88 implants were placed in the EG compared to 30 in the RG. In the EG, fixed appliances were connected to the implants within 20 days following implant installation while the fixed appliances in the RG were connected about 4 months following fixture installation. At delivery of the suprastructures, all patients were radiographically examined, an examination that was repeated at the 18- and 60-month follow-ups.

RESULTS

The analysis of the radiographs from the EG disclosed that during the observation period, between 18 and 60 months, the mean loss of bone support amounted to 0.2 mm (SD = 0.4). The corresponding value observed in the RG was 0.0 mm (SD = 0.5). During the 60-month observation period, no fixture was lost in any of the two groups examined. The implants under study as well as those in the reference material were at all observation intervals found to be clinically stable.

CONCLUSIONS

This clinical study demonstrated that it is, at least based on a 5-year observation period, possible to successfully load via a permanent fixed rigid cross-arch suprastructure titanium dental implants soon after installation. However, such a treatment approach has to be strictly limited to the interforamina area of the edentulous mandible. Furthermore, the bone resorption was found to be within the same range around such implants as around implants installed and loaded according to the original two-stage protocol.

Evaluation of a macrofoam swab protocol for the recovery of Bacillus anthracis spores from a steel surface

A protocol to recover Bacillus anthracis spores from a steel surface using macrofoam swabs was evaluated for its accuracy, precision, reproducibility, and limit of detection. Macrofoam swabs recovered 31.7 to 49.1% of spores from 10-cm2 steel surfaces with a < or =32.7% coefficient of variation in sampling precision and reproducibility for inocula of > or =38 spores.

Tumor necrosis factor alpha promoter polymorphisms in patients with juvenile idiopathic arthritis

OBJECTIVE

To investigate the potential association of tumor necrosis factor-alpha (TNF) promoter alleles within subtypes of juvenile idiopathic arthritis (JIA) compared to healthy controls in a Caucasian population.

METHODS

TNF-alpha promoter polymorphisms at positions -163, -238, -244, -308, -376 were determined in 228 patients with JIA and 196 healthy individuals. Genomic DNA was isolated and a PCR fragment of about 500 base pairs of the TNF gene promoter were amplified by PCR. Detection of polymorphisms was achieved by a single sequencing procedure.

RESULTS

The TNF -238A allele was more frequent in the psoriatic arthritis JIA subgroup compared to healthy controls as well as to non-psoriatic JIA patients (p < 0.001, chi-square-test) and was associated with the more frequent occurrence of joint erosion (p < 0.05, chi-square-test). The frequency of the TNF -308A allele was significantly lower in patients with rheumatoid factor negative polyarthritis JIA patients compared to healthy controls, respectively (p < 0.05, chi-square-test). Joint erosions were detectable more often in rheumatoid factor negative polyarthritis JIA patients with the G/A genotype (80%) than in those with the G/G genotype (45%) (p = 0.20). The rare alleles at position -376 or at positions -163 and -244 were found very infrequently.

CONCLUSION

TNF promoter polymorphisms may play a role in the pathogenesis of JIA. The TNF-238A allele seems to be associated with juvenile psoriatic arthritis. The TNF-308A allele is less frequently found in rheumatoid factor negative but not in rheumatoid factor positive polyarthritis and may therefore be associated with a more severe disease, while the more common TNF-308G allele may be protective.

The South East Queensland Forests Agreement: Lessons for Biodiversity Conservation

In Australia, regional forest agreements formed the cornerstone of strategies for resolving disputes over the logging of native forests in the last decade of the twentieth century. These disputes, driven by an increasingly vocal and influential conservation movement, coincided with changes in the nature of relationships between Commonwealth and State Governments, with the Commonwealth adopting an increasing role in environmental management (Lane 1999). Following very public disputes about the renewal of export woodchip licenses from native forests (which culminated in log truck blockades of the Commonwealth Parliament, Canberra), the Commonwealth Government adopted regional forest agreements as the mechanism for achieving sustainable management of Australia?s native hardwood forests. This was underpinned by the National Forest Policy Statement (Commonwealth of Australia 1992), which outlined principles for ecologically sustainable management of the nation?s production forests. The Commonwealth and several State Governments reached agreement to develop regional forest agreements (RFAs) for the long-term management and use of forests in ten regions (Fig. 1) (Commonwealth of Australia 2004). Key goals of the agreement were to: reconcile competing commercial, ecological and societal demands on forests in a way that was consistent with the principles and goals of ecologically sustainable forest management (Davey et al. 1997, 2002; Lane 1999); and to establish a comprehensive, adequate and representative reserve system, based on the nationallyagreed JANIS criteria (JANIS 1997).

The marrow cell continuum: stochastic determinism

Traditional models of hematopoiesis have been hierarchical in nature. Over the past 10 years, we have developed data indicating that hematopoiesis is regulated in a continuum with deterministic and stochastic components. We have shown that the most primitive stem cells, as represented by lineage negative rhodamine(low) Hoechst(low) murine marrow cells are continuously or intermittently cycling as determined by in vivo BrdU labeling. When marrow stem cells are induced to transit cell cycle by in vitro exposure to cytokines, either IL-3, IL-6, IL-11, and steel factor or thrombopoietin, FLT3 ligand, and steel factor, they progress through cycle in a highly synchronized fashion. We have determined that when the stem cells progress through a cytokine stimulated cell cycle the homing, engraftment, adhesion protein, global gene expression, and hematopoietic differentiation phenotypes all change in a reversible fashion. This has led to the continuum model, in which, with cycle transit, chromatin is continually changing altering open transcription areas and providing a continually changing landscape of transcriptional opportunity. More recently, we have extended the changing differentiation profiles to differentiation into lung cells and found that non-hematopoietic differentiation also shows cycle related reversibly modulation. These observations all together support a continuum model of stem cell regulation in which the phenotype of the marrow stem cells is continually and reversibly changing over time.

54 COMPOSITION OF ALLANTOIC FLUID IN CATTLE PREGNANT WITH AI-, IVP-, OR NUCLEAR TRANSFER-GENERATED EMBRYOS

Abnormal placentation, pregnancy failure, and hydroallantois are associated with somatic cell nuclear transfer (SCNT) in cattle. Identification of diagnostic markers for abnormal placentation in early gestation would permit therapeutic intervention. Ultrasonography and transvaginal sampling of amniotic and/or allantoic (fetal) fluid enables regular monitoring of fetal health. We report on the composition of serial samples of fetal fluid from individual cows between Days 70–130 of gestation and the potential of steroid and electrolyte composition as an early diagnostic marker for the subsequent occurrence of hydroallantois in SCNT pregnancies in cattle. On Day 70, pregnancy rates were 50% and 60% for cows or heifers implanted with single in vitro-fertilized (IVP, 20/40) or SCNT (25/42) embryos, respectively, and 67% for pregnancies generated by artificial insemination (AI, 12/18). Resulting fetuses were either clones (SCNT) or offspring (IVP/AI) of a donor Holstein bull. Fetal fluids, sampled using ultrasound-guided transvaginal puncture, were collected on Days 70, 100, and 130 of gestation (n = 12 and 139 for amniotic and allantoic samples, respectively). Placental and fetal morphological data were collected following slaughter between Days 135–163 of gestation (n = 14, 20, and 10 for SCNT, IVP, and AI groups, respectively). Fetal fluids were analyzed for progesterone, estrone sulphate, sodium, chloride, potassium, creatinine, urea, calcium, magnesium and phosphate. Pregnancy outcomes for the SCNT group were retrospectively classified as: Fail 100 (pregnancies failing between Days 70–99; n = 6); Fail 130 (failing between Days 100–129; n = 5); Hydrops (greater than 10 L combined amniotic and allantoic fluid at postmortem between Days 135–163; n = 8) and SCNT Pregnant 150 (pregnant between Days 135–163; n = 6). IVP and AI pregnancies were classified as IVP or AI Pregnant 150. Fluid composition was analyzed by ANOVA on log-transformed data. On Day 70, allantoic progesterone and estrone sulphate concentrations were significantly higher (P < 0.05) for the SCNT cows compared to the IVP/AI Pregnant 150 cows. On Day 70, allantoic potassium, chloride, creatinine, and urea concentrations were significantly higher (P < 0.05) for the SCNT Hydrops cows compared to the IVP/AI Pregnant 150 cows. In addition, Day 70 allantoic creatinine and urea concentrations were significantly higher (P < 0.05) for the SCNT Hydrops cows compared to other SCNT groups. By Day 100, allantoic chloride, creatinine, and urea concentrations in SCNT Hydrops cows were significantly lower (P < 0.05) than in IVP/AI Pregnant 150 groups. We conclude that elevated Day 70 allantoic urea and creatinine concentrations are potential early diagnostic markers predicting hydroallantois in recipient cattle carrying SCNT fetuses. Further investigation of these markers in other somatic donor cell lines used for nuclear transfer is warranted to determine their general utility.

High ice nucleation temperature of zebrafish embryos: slow-freezing is not an option

Although fish embryos have been used in a number of slow-freezing cryopreservation experiments, they have never been successfully cryopreserved. In part this is because little is known about whether ice forms within the embryo during the slow-freezing dehydration process. Therefore, we examined the temperature of intraembryonic ice formation (T(IIF)) and the temperature of extraembryonic ice formation (T(EIF)), using a cryomicroscope. We used both unmodified zebrafish embryos and those with water channels (aquaporin-3 or AQP3) inserted into their membranes to increase permeability to water and cryoprotectants, examined at 100% epiboly to the 6-somite stage. In these experiments we examined: (1) the spontaneous freezing of (external) solutions; (2) the spontaneous freezing of solutions containing embryos; (3) the effect of preloading the embryos with cryoprotectants on T(IIF); (4) whether preloading the embryos with cryoprotectant helps in survival after nucleating events in the solution; and (5) the damaging effects of extracellular nucleation events versus solution toxicity on the embryos. The solutes alone (embryo medium--EM, sucrose culture medium, 1 M propylene glycol in EM, and 1 M propylene glycol in a sucrose culture medium) froze at -14.9 +/- 1.1, -17.0 +/- 0.3, -17.8 +/- 1.0, and -17.7 +/- 1.4, respectively. There was no difference amongst these means (P > 0.05), thus adding cryoprotectant did not significantly lower the nucleation point. Adding embryos (preloaded with cryoprotectant or not) did not change the basic freezing characteristics of these solutes. In all these experiments, (T(EIF)) equaled (T(IIF)), and there was no difference in the freezing point of the solutions with or without the embryos (P > 0.05). Additionally, there was no difference in the freezing characteristics of embryos with and without aquaporins (P > 0.05). The formation of intraembryonic ice was lethal to the zebrafish embryos in all cases. But this lethal outcome was not related to solution injury effects, because 88-98% of embryos survived when exposed to a higher solute concentration with no ice present. Taken together, these data suggest that slow-freezing is not a suitable option for zebrafish embryos. The mechanism of this high temperature nucleation event in zebrafish embryos is still unknown.

Preparations for the Safe Management of Severe Acute Respiratory Syndrome (SARS) Research Protocol Patients

ISSUE: The Warren G Magnuson Clinical Center (CC) strives to achieve a balance between its mission and worker and patient safety.

PROJECT: As part of its mission as one of the government's primary research facilities, the CC must be able to address epidemiologically significant public health concerns as they arise. After its initial description in the fall of 2002, the global threat of SARS became readily apparent. To address its mission, investigators working at the CC designed two protocols to study this new disease. To protect our patients and our staff, we quickly developed infection control guidelines based on what was known about the epidemiology and pathogenesis of this new disease.

RESULTS: We created a multidisciplinary team to identify risk points during the admission and treatment phases of these protocols. This group met once or twice weekly for 6 months. New policies and procedures were created which were patterned after the CDC guidelines but which met the unique needs of our existing infrastructure and patient populations. We created a new position (isolation monitor) to ensure compliance with infection control precautions. We also conducted a failure mode and effects analysis (FMEA) to identify additional areas of risk. Policies and procedures were reviewed by: 1) a multi-institute physician committee, 2) an external expert in hospital epidemiology, and 3) the CC Medical Executive Committee. Detailed practice sessions have been held to ensure compliance with these new and detailed precautions.

LESSONS LEARNED: Readiness for complex infectious diseases is multifaceted and requires advance planning and detailed assessments. Preparing for SARS has placed our organization in a much better position to deal with emerging airborne infectious diseases.

The amount of neurofilaments aggregated in the cell body is controlled by their increased sensitivity to trypsin-like proteases

Neurofilaments are synthesised and assembled in neuronal cell bodies, transported along axons and degraded at the synapse. However, in several pathological situations they aggregate in cell bodies or axons. To investigate their turnover when separated from their normal site of degradation, we used a previously described transgenic model characterised by perikaryal retention of neurofilaments, and compared the basic features of both neurofilament synthesis and degradation with that observed in normal mice. Despite the massive perikaryal aggregates, neurofilament transcript levels were found to be unchanged, whereas the total accumulation of neurofilament proteins was markedly reduced. Neurofilaments isolated from transgenic samples are more sensitive to both trypsin and α-chymotrypsin mediated proteolysis. Consistent with their greater in vitro sensitivity, trypsin immunolabeling of cell bodies was stronger in transgenic mice. These results show a novel mechanism to regulate the amount of neurofilaments when they abnormally aggregate.

Analysis of the costs of diagnosing cystic fibrosis with a newborn screening program

OBJECTIVES

To compare the cost of diagnosing cystic fibrosis (CF) through a newborn screening program with the traditional method and to estimate the cost of CF diagnosis if a national newborn screening program is implemented.

STUDY DESIGN

Surveys were conducted to determine the annual number of sweat tests in 1991 and in 2000 after implementation of statewide screening. A national survey of sweat test costs was used to estimate the annual expense for diagnosing CF in the United States through newborn screening.

RESULTS

Since the introduction of newborn screening for CF, the numbers of sweat tests ordered annually have decreased from 1670 to 804 (including 134 follow-up tests from screening). The current estimated annual cost of Wisconsin CF newborn screening and diagnosis is $4.58 per newborn infant. The estimated annual cost per newly diagnosed CF infant using the traditional method is $4.97 per newborn infant. If no additional sweat tests were ordered outside of the newborn screening program, the estimated annual cost of a Wisconsin CF newborn screening and diagnosis is $2.66 per newborn and $2.47 per newborn for a national CF newborn screening program.

CONCLUSIONS

A CF newborn screening program provides a potentially cost-saving alternative to the traditional method of diagnosis of CF.

Assessment of cognitive functioning in men who batter

The present investigation examined neuropsychological functioning in 50 male batterers court-ordered into treatment and 23 nonpatient controls. Subjects were administered a neuropsychological screening battery consisting of the Screening Test for the Luria-Nebraska Neuropsychological Battery, the Stroop Color and Word Test, two memory subtests from the Luria-Nebraska Neuropsychological Battery-III (Figural Memory and Delayed Figural Memory), and two subtests from the Halstead-Reitan Neuropsychological Battery (Trails A & B). Subjects were categorized as having neuropsychological dysfunction if their scores exceeded the statistical cut offs on two or more subtests. Results indicated that 24 (48%) of the male batterers exhibited cognitive dysfunction, as compared to only 1 (4.3%) of the nonpatient controls. Inspection of individual neuropsychological measures indicated poorer performance across all subtests for impaired male batterers as compared to both nonimpaired batterers and normal controls. In contrast, no significant differences on any of these measures emerged between nonimpaired male batterers and normal controls. Implications for the appropriate screening and treatment of male batterers are discussed.

Sleep disturbance after burn injury

This study describes sleep disturbance and related factors in a group of 74 patients at 1 week after discharge using a sleep problems questionnaire developed by the authors. Results indicated that a significant proportion of patients reported a problem with their sleep (73%). Several items were identified as highly prevalent, including frequent nighttime awakenings (87%), napping during the daytime (65%), sleeping alone (64%), experiencing pain during the night (62%), and difficulties with sleep onset (62%). Results suggest numerous possible interventions to improve patients' sleep quality. The usefulness of a more extensive questionnaire was also indicated.

Regulation of proliferation of prostate epithelial cells by 1,25-dihydroxyvitamin D3 is accompanied by an increase in insulin-like growth factor binding protein-3

The biologically active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) has been shown to regulate the proliferation of human prostate epithelial cell lines. Since the insulin-like growth factor (IGF) system is involved in the transformation process of epithelial cells, the following study was undertaken to determine if the IGF system, in particular IGF binding protein-3 (IGFBP-3), is altered by 1,25-(OH)2D3 in normal prostate epithelial cells as part of a mechanism for inhibition of transformation. Two cell systems were used in this study: (1) primary cultures of benign human prostate epithelial cells (PECs) and (2) an SV40-T immortalized prostate epithelial cell line (P153) that is non-tumorigenic. 1,25-(OH)2D3 was added to parallel sets of PECs and P153 cells in addition to the presence or absence of IGF-I or des(1-3)IGF-I. Treatment with 1,25-(OH)2D3 resulted in significant growth inhibition of both PECs and P153 cells. Furthermore, 1,25-(OH)2D3 inhibited IGF-induced proliferation, but this was partially reversed by high concentrations of IGF-I. Western ligand blots of condition media demonstrated a significant increase in IGFBP-3; likewise Northern blots demonstrated an increase in mRNA for IGFBP-3. Proliferation assays using an antibody designed to block the IGF-independent effects of IGFBP-3 failed to reverse the inhibitory effect of 1,25-(OH)2D3. Thus, IGFBP-3 acts in an IGF-dependent manner to inhibit cell growth of benign prostate epithelial cells.

Selected statistical issues in group randomized trials

Group randomized trials (GRTs) in public health research typically use a small number of randomized groups with a relatively large number of participants per group. Two fundamental features characterize GRTs: a positive correlation of outcomes within a group, and the small number of groups. Appropriate consideration of these fundamental features is essential for design and analysis. This paper presents the fundamental features of GRTs and the importance of considering these features in design and analysis. It also reviews and contrasts the main analytic methods proposed for GRTs, emphasizing the assumptions required to make these methods valid and efficient. Also discussed are various design issues, along with guidelines for choosing among them. A real data example illustrates these issues and methods.

A distal upstream enhancer from the myelin basic protein gene regulates expression in myelin-forming schwann cells

In peripheral nerves, large caliber axons are ensheathed by myelin-elaborating Schwann cells. Multiple lines of evidence demonstrate that expression of the genes encoding myelin structural proteins occurs in Schwann cells in response to axonal instructions. To gain further insight into the mechanisms controlling myelin gene expression, we used reporter constructs in transgenic mice to search for the DNA elements that regulate the myelin basic protein (MBP) gene. Through this in vivo investigation, we provide evidence for the participation of multiple, widely distributed, positive and negative elements in the overall control of MBP expression. Notably, all constructs bearing a 0.6 kb far-upstream sequence, designated Schwann cell enhancer 1 (SCE1), expressed at high levels in myelin-forming Schwann cells. In addition, robust targeting activity conferred by SCE1 was shown to be independent of other MBP 5' flanking sequence. These observations suggest that SCE1 will make available a powerful tool to drive transgene expression in myelinating Schwann cells and that a focused analysis of the SCE1 sequence will lead to the identification of transcription factor binding sites that positively regulate MBP expression.

Cochlear Implants in Five Cases of Auditory Neuropathy: Postoperative Findings and Progress

OBJECTIVES

To review our experiences with some of the preoperative and postoperative findings in five children who were diagnosed with auditory neuropathy and were provided with cochlear implants. We describe changes in auditory function, which enabled these children to have significant improvement in their hearing and communication skills.

STUDY DESIGN

Pre- and postoperatively, these children received complete medical examinations at Mayo Clinic, including related consultations in audiology, pediatrics, neurology, medical genetics, otolaryngology, psychology, speech pathology, and radiology.

METHODS

These children typically had additional medical and audiological examinations at more than one medical center. The hearing assessments of these children included appropriate behavioral audiometric techniques, objective measures of middle ear function, acoustic reflex studies, transient (TOAE) or distortion product (DPOAE) otoacoustic emissions, auditory brainstem responses (ABR), and, in some cases, transtympanic electrocochleography (ECoG). After placement of the internal cochlear implant devices (Nucleus CI24), intraoperatively we measured electrode impedances, visually detected electrical stapedius reflexes (VESR) and neural response telemetry (NRT). These intraoperative objective measures were used to help program the speech processor for each child. Postoperatively, each child has had regular follow-up to assure complete healing of the surgical incision, to assess their general medical conditions, and for speech processor programming. Their hearing and communication skills have been assessed on a regular basis. Postoperatively, we have also repeated electrode impedance measurements, NRT measurements, otoacoustic emissions, and electrical auditory brainstem responses (EABR). We now have 1 year or more follow-up information on the five children.

RESULTS

The five children implanted at Mayo Clinic Rochester have not had any postoperative medical or cochlear implant device complications. All of the children have shown significant improvements in their sound detection, speech perception abilities and communication skills. All of the children have shown evidence of good NRT results. All but case D (who was not tested) showed evidence of good postoperative EABR results. Otoacoustic emissions typically remained in the non-operated ear but, as expected, they are now absent in the operated ear.

CONCLUSION

Our experiences with cochlear implantation for children diagnosed with auditory neuropathy have been very positive. The five children we have implanted have not had any complications postoperatively, and each child has shown improved listening and communication skills that have enabled each child to take advantage of different communication and educational options.

Is it Alzheimer's? Neuropsychological testing helps to clarify diagnostic puzzle

This patient displayed a pattern of neuropsychological test results that indicated early Alzheimer's dementia. Using neuropsychological testing to make the diagnosis provided an answer for the patient, family, and psychiatrist, who all recognized a problem, and allowed for future planning. Recommendations for the patient included: psychoeducation and support for the patient and family assistance with planning for the future, including discussions of advance directives and financial management re-evaluation of the patient's ability to drive a motor vehicle a trial of a cholinesterase inhibitor such as donepezil or rivastigmine ongoing health maintenance, including periodic screening for depression and other psychiatric symptoms repeat neuropsychological assessment in 6 months to 1 year to assess rate of decline and confirm the diagnosis.

Evidence that smokeless tobacco use is a gateway for smoking initiation in young adult males

BACKGROUND

This study was designed to test the hypothesis that smokeless tobacco (SLT) serves as a gateway drug for smoking among young adult males. Methods. A cohort (n = 7,865) of U.S. Air Force recruits who claimed to have never smoked cigarettes was followed prospectively for 1 year. The participants were male, 32.9% were ethnic minorities, and their average age was 19.84 years (SD = 2.29). Among recruits entering basic military training, 403 (5.1%) reported current SLT use and 198 (2.5%) reported a past history of SLT use.

RESULTS

At the 1-year follow-up current SLT users were 233% more likely to have initiated smoking than nonusers (odds ratio = 2.33, 95% CI = 1.84-2.94). Similarly, recruits who reported past SLT use were 227% more likely to begin smoking than participants who had never used SLT (odds ratio = 2.27, 95% CI = 1.64-3.15). SLT use remained a potent predictor of smoking initiation in a multivariate logistic model that included demographic factors and other risk factors for initiation.

CONCLUSIONS

SLT use appears to be an important predictor of smoking initiation among young adult males. This study suggests that smoking prevention and cessation programs should also include strategies related to SLT use.

Cloning and functional expression in Escherichia coli of a cDNA encoding cardenolide 16'-O-glucohydrolase from Digitalis lanata Ehrh

A clone of cardenolide 16'-O-glucohydrolase cDNA (CGH I) was obtained from Digitalis lanata which encodes a protein of 642 amino acids (calculated molecular mass 73.2 kDa). The amino acid sequence derived from CGH I showed high homology to a widely distributed family of beta-glucohydrolases (glycosyl hydrolases family 1). The recombinant CGH I protein produced in Escherichia coli had CGH I activity. CGH I mRNA was detected in leaves, flowers, stems and fruits of D. lanata.

Disrupted development of the cerebral hemispheres in transgenic mice expressing the mammalian Groucho homologue transducin-like-enhancer of split 1 in postmitotic neurons

Transducin-like Enhancer of split (TLE) 1 is a mammalian transcriptional corepressor homologous to Drosophila Groucho. In Drosophila, Groucho acts together with bHLH proteins of the Hairy/Enhancer of split (HES) family to negatively regulate neuronal differentiation. Loss of the functions of Groucho or HES proteins results in supernumerary central and peripheral neurons. This suggests that mammalian TLE/Groucho family members may also be involved in the regulation of neuronal differentiation. Consistent with this possibility, TLE1 is expressed in proliferating neural progenitor cells of the central nervous system, but its expression is transiently down-regulated in newly generated postmitotic neurons. Based on these observations, we investigated whether persistent TLE1 expression in postmitotic neurons would perturb the normal course of neuronal development. Transgenic mice were derived in which the human TLE1 gene is regulated by the promoter of the Talpha1 alpha-tubulin gene, which is exclusively expressed in postmitotic neurons. In these mice, constitutive expression of TLE1 inhibits neuronal development in the embryonic forebrain leading to increased apoptosis and neuronal loss in the ventral and dorsal telencephalon. These results provide the first direct evidence that TLE1 is an important negative regulator of postmitotic neuronal differentiation in the mammalian central nervous system.

Neural response telemetry with the nucleus CI24M cochlear implant

OBJECTIVES

To review our intraoperative and postoperative testing protocol for cochlear implant patients. This study describes the methodologies and applications of a new technique called neural response telemetry (NRT) for the Nucleus CI24M cochlear implant system. NRT uses radiofrequency telemetry technology to measure the action potentials of the auditory nerve.

STUDY DESIGN

We have developed a specific protocol for intraoperative testing of the implant device before, during, and after implantation. This includes device integrity tests, visual detection of electrical stapedius muscle reflexes (VESR), and NRT.

METHODS

Our methodologies use the commercial software (Windows-based Diagnostic and Programming System [WIN-DPS] and NRT) for the Nucleus CI24M. We describe the details of our protocol used on all of the patients (14 adults and 14 children) who received CI24M implants at Mayo Clinic (Rochester, MN). Our protocol correlates the NRT threshold with the behavioral responses for each patient on at least four electrodes.

RESULTS

From August 1, 1998, to December 31,1998, we completed electrode integrity tests, NRT, and VESR testing intraoperatively on 12 patients with the Nucleus CI24M. We have measured normal implant function on all 28 of our CI24M patients with one exception. One of our children had a device failure after approximately 4 months as a result of head trauma. We have also obtained NRT results from an additional 10 patients postoperatively.

CONCLUSIONS

The measurement of device and electrode array function is quite simple with the CI24M software. These measurements can be obtained intraoperatively as well as postoperatively. We conclude that VESR and NRT measurements can be very helpful in programming for patients with cochlear implants, especially children, because they provides us with target settings for the speech processor.

Preparation of nuclear extracts from myelinating Schwann cells

Myelination of peripheral nerve fibres is performed by Schwann cells and is associated with the coordinate upregulation of lipid synthesis and multiple genes encoding myelin-specific proteins. Both the decision to enter into a myelinating phenotype and subsequently, the quantity of myelin that each Schwann cell elaborates appear to be controlled by axonal signals. Understanding of the relevant signaling pathways and the downstream transcription factors and cis elements that confer myelin gene expression is notably limited. In large part, this has resulted directly from a lack of methods for obtaining nuclear extracts from myelinating Schwann cells thus precluding the application of numerous powerful molecular techniques. In this report, we describe a method that overcomes this limitation for the myelinating Schwann cells in the sciatic nerves of the mouse. During the evolution of the method, its effectiveness was monitored using an oligonucleotide containing the binding site for KROX-20, a transcription factor known to be present in myelinating Schwann cells. Following technical development, the optimized protocol has proven to be entirely reliable and thus novel experimental strategies now can be applied to the investigation of the molecular mechanisms controlling gene expression in peripheral nerves.

Bioreactor development for tissue-engineered cartilage

The development of tissue engineered cartilage is emerging as a potential treatment for the repair of cartilage defects. By seeding chondrocytes onto poly-glycolic acid (PGA) biodegradable scaffolds within a convective-flow bioreactor, the synthesis of tissue-engineered articular cartilage has been recently demonstrated. The ability to cultivate and manipulate this cell-polymer construct to possess specific dimensions, as well as biochemical and biomechanical properties is critical for potential application as an in vivo therapy of damaged articular surfaces. Bioreactor design requirements for stages from research to development to commercialization are discussed. Advantages and limitations to various bioreactor designs are critiqued. These studies illustrate the ability to synthesize tissue-engineered cartilage under convective-flow conditions for potential human tissue repair.

The flat-top gene is required for the expansion and regionalization of the telencephalic primordium

The telencephalic vesicles form in the mouse embryo by the expansion of precursor regions in the anterior neural tube. Once the vesicles have formed, discrete dorsal and ventral territories can be recognized that later give rise to cortical and subcortical structures, respectively. To investigate the mechanisms that regulate the expansion and regionalization of the telencephalon, we have carried out a screen to identify recessive mutations that disrupt these events. We isolated a mouse mutant in which an early and critical step in development of the telencephalic vesicles is disrupted. Telencephalic primordia are present in flat-top embryos but they fail to progress to form the telencephalic vesicles. An increased rate of proliferation in the forebrain neurectoderm that accompanies telencephalic expansion in wild-type embryos fails to occur in flat-top embryos. Regionalization events that would normally take place during expansion of the primordia also fail to occur. Thus the phenotype of the flat-top mouse reveals that outgrowth of the telencephalic vesicles and their regionalization are coupled processes.

Interferon-gamma in progression to chronic demyelination and neurological deficit following acute EAE

The cytokine interferon-gamma (IFNgamma) is implicated in the induction of acute CNS inflammation, but it is less clear what role if any IFNgamma plays in progression to chronic demyelination and neurological deficit. To address this issue, we have expressed IFNgamma in myelinating oligodendrocytes of transgenic mice. MHC I immunostaining and iNOS mRNA were upregulated in their CNS, but such transgenic mice showed no spontaneous CNS inflammation or demyelination, and the incidence, severity, and histopathology of experimental autoimmune encephalomyelitis (EAE) were similar to nontransgenic controls. In contrast to control mice, which remit from EAE with resolution of glial reactivity and leukocytic infiltration, transgenics showed chronic neurological deficits. While activated microglia/macrophages persisted in demyelinating lesions for over 100 days, CD4(+) T lymphocytes were no longer present in CNS. IFNgamma therefore may play a role in chronic demyelination and long-term disability following the induction of demyelinating disease. Because IFNgamma may have neural as well as immune-infiltrating origins, these findings generate a new perspective on its role in the CNS.

Elevated intracellular calcium levels in cerebellar granule neurons of weaver mice

Weaver mice carry a mutation in the pore domain of the Girk2 (Kcnj6) gene. The mutation causes GIRK2 containing channels to lose ion selectivity and to become constitutively active. It is not known how this alteration in ion channel activity causes in cerebellar granule cells the defects in neurite extension, cell migration and induction of cell death that are characteristic of weaver mice. One possibility is that the mutation causes an inability to regulate intracellular calcium levels properly. We tested this hypothesis by measuring intracellular calcium levels in granule cells and Purkinje cells in slices from the cerebellum of weaver mice. We report here that weaver mice have increases in resting calcium levels in their granule cells, which may account for the multiple effects of the weaver mutation upon these cells.

The effect of WIC participation on small-for-gestational-age births: Michigan, 1992

OBJECTIVE

This study examined the relationship between enrollment in the Special Supplemental Nutrition Program for women, Infants, and Children (WIC) and delivery of small-for-gestational-age infants.

METHODS

WIC records were linked with birth certificates for 1992 full-term births; 41,234 WIC records and 18,34 non-WIC records were identified. Length of participation was defined by gestational age at enrollment. Logistic regression was used to examine the association between WIC participation and small-for-gestational-age births.

RESULTS

Odds ratios for small-for-gestational-age birth decreased with increasing length of enrollment in WIC.

CONCLUSIONS

Enrollment in WIC is associated with a lower prevalence of small-for-gestational-age deliveries.