Transient immunosuppression by FK506 permits a sustained high-level dystrophin expression after adenovirus-mediated dystrophin minigene transfer to skeletal muscles of adult dystrophic (mdx) mice

Adenovirus (AV)-mediated gene transfer into skeletal muscles of adult immune-competent animals has been limited by the fact that a cell-mediated immune attack of the host against transduced muscle fibers prevented efficient long-term transgene expression. More recently, various immunomodulating strategies have been shown to improve the longevity of transgene expression after AV-mediated gene transfer. In this study we treated adult dystrophic (mdx) mice with daily subcutaneous injections of the immunosuppressive drug FK506 (tacrolimus) over 5, 10, 30 and 60 days after AV-mediated dystrophin gene transfer and compared the transduction level with saline-injected mdx controls. We show that daily FK506 treatment after AV-mediated dystrophin gene transfer into adult mdx muscle results in the maintenance of the initial transgene expression for at least 2 months, even when FK506 treatment was discontinued after 1 month. This is in keeping with the marked reduction of inflammatory infiltrates and the reduced activation level (inducible nitric oxide synthase) of macrophages in adenoviral recombinant (AVR)-injected muscles of FK506-treated animals. Moreover, we find that FK506 efficiently suppresses the humoral immune response against both the vector proteins and the transgene protein product (dystrophin). Furthermore, we demonstrate that continuous FK506 treatment over 30 days significantly improves the efficiency of gene transfer when the same vector is readministered to an animal which had been transduced 20 days earlier. In conclusion, the data suggest that sensitization by the initial antigenic load of the AVR application plays a pivotal role in triggering the humoral and cellular immune response of the host, which can be significantly counteracted by relatively short-term immunosuppressive treatment. These findings have important implications for the design of future human trials for gene replacement therapy in Duchenne muscular dystrophy.

Cloning, chromosomal localization, physical mapping, and genomic characterization of HKR3

The Krüppel-type zinc finger proteins are members of a conserved family of transcription factors that are important in developmental regulation. Altered expression of several of these proteins has been implicated in human diseases, including cancer. We report the cloning, mapping, and characterization of the zinc finger gene Human Krüppel-Related 3 (HKR3). Genomic clones of HKR3 were isolated from a P1 library and localized to human chromosome subband 1p36.3 by human-rodent somatic cell hybrid mapping and fluorescence in situ hybridization. The gene was physically mapped to within 40 kb of D1S214 by YAC content and long-range restriction mapping. HKR3 spans 9.5 kb of genomic DNA and is contained in 11 exons. Sequencing defined each of the exon/intron splice site junctions and identified a CpG island in the 5' region of the gene. HKR3 is ubiquitously expressed in human tissues as at least two major transcripts, the shorter of which excludes a conserved finger-associated box and a putative acidic activation domain contained in the full-length transcript. HKR3 is a novel zinc finger gene that maps to a region of the genome commonly rearranged or deleted in human cancers.

Correlation of vacuous chewing movements with morphological changes in rats following 1-year treatment with haloperidol

Long-term treatment with the typical antipsychotic drug, haloperidol, can lead to a sometimes irreversible motor disorder, tardive dyskinesia (TD). It has been hypothesized that increased release of glutamate due to prolonged neuroleptic drug treatment may result in an excitotoxic lesion in specific neuronal populations within the basal ganglia, leading to TD. We reported that treatment with haloperidol for 1 month results in an increase in the mean percentage of striatal asymmetric synapses containing a perforated postsynaptic density (PSD) and that these synapses are glutamatergic. Using quantitative immunocytochemistry, we found that depending on how long the animals had been off haloperidol following subchronic (30 d) treatment, there was either a decrease (1 day off) or increase (3-4 days off) in the density of glutamate immunolabeling within the presynaptic terminals of synapses with perforated PSDs. Using a rat model for TD, animals in the current study were treated for 1 year with haloperidol and spontaneous oral dyskinesias (i.e. vacuous chewing movements, VCMs) were recorded. In these long-term treated animals we wanted to determine if there was a correlation between glutamate function, as measured by changes in synapses with perforated PSDs and the density of nerve terminal glutamate immunoreactivity, and VCM behavior. In drug treated rats which demonstrated either a high or low rate of VCMs, there was a significant increase in the mean percentage of asymmetric synapses in the dorsolateral striatum with perforated PSDs in both haloperidol-treated groups compared to vehicle-treated rats. There was a small but significant increase in the density of glutamate immunolabeling within striatal nerve terminals of the high VCM group compared to the low VCM group. There was, however, no difference in the density of glutamate immunolabeling between the high VCM group compared to the vehicle-treated animals. One reason for this lack of difference was partially due to a significant increase in nerve terminal area within the high VCM group compared to either the low VCM- or vehicle-treated groups. The larger nerve terminal size in the high VCM group may be due to a small but sustained increase in glutamate neurotransmitter release with the ability of the terminal to maintain its supply of glutamate, while the terminals in the low VCM group showed evidence of glutamate depletion. This finding would be consistent with the hypothesis that increased glutamatergic activity may be associated with TD.

The effect of preoperative tranexamic acid on blood loss after cardiac operations in children

Children undergoing cardiac operations in which cardiopulmonary bypass is used are at risk of significant postoperative blood loss. The acquired coagulopathy is complex but is thought to be due, in part, to excessive fibrinolysis. We examined the possibility of reducing postoperative blood loss in children by using the antifibrinolytic drug tranexamic acid. Using a prospective, randomized, double-blind study design, we administered a single dose of tranexamic acid (50 mg/kg intravenously) or saline placebo, before skin incision, in 88 children undergoing cardiac operations. Post-operative blood loss and fluid replacement were recorded for the next 24 hours. In addition, hemoglobin, platelet counts, and coagulation measures were recorded every 6 hours. When all patients were examined, there was no significant difference in postoperative blood loss between the treated and placebo groups (21.2 +/- 12 ml/kg per 24 hours, tranexamic acid, vs 27.2 +/- 20.3 mls/kg per 24 hours, placebo). However, when the children with cyanosis were analyzed separately, there was a highly significant difference in blood loss between the groups during the first 6 hours (11.2 +/- 3.7 ml/kg per 6 hours, tranexamic acid, vs 27.2 +/- 11.4 mls/kg per 6 hours, placebo; p < 0.002), as well as the overall 24 hour study period (23.7 +/- 7.5 mls/kg per 24 hours, tranexamic acid, vs 48.9 +/- 27.6 mls/kg per 24 hours, placebo; p < 0.02). Also significantly less blood and blood products were administered to the treated cyanosed group. Tranexamic acid produced a significant reduction in postoperative blood loss and blood product requirements in children with cyanosis undergoing heart operations. The drug had no effect in children without cyanosis or those requiring a second thoracotomy.

Activation of corticostriatal pathway leads to similar morphological changes observed following haloperidol treatment

Treatment with haloperidol, a dopamine receptor D-2 antagonist, for one month resulted in an increase in the mean percentage of asymmetric synapses containing a discontinuous, or perforated, postsynaptic density (PSD) [Meshul et al. (1994) Brain Res., 648:181-195] and a change in the density of striatal glutamate immunoreactivity within those presynaptic terminals [Meshul and Tan (1994) Synapse, 18:205-217]. We speculated that this haloperidol-induced change in glutamate density might be due to an activation of the corticostriatal pathway. To determine if activation of this pathway leads to similar morphological changes previously described following haloperidol treatment, GABA (10(-5) M, 0.5 microliters) was injected into the thalamic motor (VL/VM) nuclei daily for 3 weeks. This treatment resulted in an increase in the mean percentage of striatal asymmetric synapses containing a perforated PSD and an increase in the density of glutamate immunoreactivity within nerve terminals of asymmetric synapses containing a perforated or non-perforated PSD. Subchronic injections of GABA into the thalamic somatosensory nuclei (VPM/VPL) had no effect on the mean percentage of synapses with perforated PSDs but resulted in a small, but significant, increase in density of glutamate immunoreactivity. Using in vivo microdialysis, an acute injection of GABA (10(-5) M, 15 microliters) into VL/VM resulted in a prolonged rise in the extracellular level of striatal glutamate. The increase in asymmetric synapses with perforated PSDs and in glutamate immunoreactivity within nerve terminals of the striatum following either subchronic haloperidol treatment or GABA injections into VL/VM suggest that an increase in glutamate release may be a common factor in these two experiments. It is possible that the extrapyramidal side effects associated with haloperidol treatment may be due, in part, to an increase in release of glutamate within the corticostriatal pathway.

An analysis of engraftment kinetics as a function of the CD34 content of peripheral blood progenitor cell collections in 692 patients after the administration of myeloablative chemotherapy

The CD34 antigen is expressed by committed and uncommitted hematopoietic progenitor cells and is increasingly used to assess stem cell content of peripheral blood progenitor cell (PBPC) collections. Quantitative CD34 expression in PBPC collections has been suggested to correlate with engraftment kinetics of PBPCs infused after myeloablative therapy. We analyzed the engraftment kinetics as a function of CD34 content in 692 patients treated with high-dose chemotherapy (HDC). Patients had PBPCs collected after cyclophosphamide based mobilization chemotherapy with or without recombinant human granulocyte colony-stimulating factor (rhG-CSF) until > or = 2.5 x 10(6) CD34+ cells/kg were harvested. Measurement of the CD34 content of PBPC collections was performed daily by a central reference laboratory using a single technique of CD34 analysis. Forty-five patients required a second mobilization procedure to achieve > or = 2.5 x 10(6) CD34+ cells/kg and 15 patients with less than 2.5 x 10(6) CD34+ cells/kg available for infusion received HDC. A median of 9.94 x 10(6) CD34+ cells/kg (range, 0.5 to 112.6 x 10(6) CD34+ cells/kg) contained in the PBPC collections was subsequently infused into patients after the administration of HDC. Engraftment was rapid with patients requiring a median of 9 days (range, 5 to 38 days) to achieve a neutrophil count of 0.5 x 10(9)/L and a median of 9 days (range, 4 to 53+ days) to achieve a platelet count of > or = 20 x 10(9)/L. A clear dose-response relationship was evident between the number of CD34+ cells per kilogram infused between the number of CD34+ cells per kilogram infused and neutrophil and platelet engraftment kinetics. Factors potentially influencing the engraftment kinetics of neutrophil and platelet recovery were examined using a Cox regression model. The single most powerful mediator of both platelet (P = .0001) and neutrophil (P = .0001) recovery was the CD34 content of the PBPC product. Administration of a post-PBPC infusion myeloid growth factor was also highly correlated with neutrophil recovery (P = .0001). Patients receiving high-dose cyclophosphamide, thiotepa, and carboplatin had more rapid platelet recovery than patients receiving other regimens (P = .006), and patients requiring 2 mobilization procedures versus 1 mobilization procedure to achieve > or = 2.5 x 10(6) CD34+ cells/kg experienced slower platelet recovery (P = .005). Although a minimal threshold CD34 dose could not be defined, > or = 5.0 x 10(6) CD34+ cells/kg appears to be optimal for ensuring rapid neutrophil and platelet recovery.

Molecular characterization and chromosomal localization of DRT (EPHT3): a developmentally regulated human protein-tyrosine kinase gene of the EPH family

By screening a human fetal brain cDNA expression library using a monoclonal antiphosphotyrosine antibody and by 5' RACE procedures, we have isolated overlapping cDNAs encoding a receptor-type tyrosine kinase belonging to the EPH family, DRT (Developmentally Regulated EPH-related Tyrosine kinase gene). The DRT gene is expressed in three different size transcripts (i.e. 4, 5 and 11 kb). DRT transcripts are expressed in human brain and several other tissues, including heart, lung, kidney, placenta, pancreas, liver and skeletal muscle, but the 11 kb DRT transcript is preferentially expressed in fetal brain. Steady-state levels of DRT mRNA in several tissues, including brain, heart, lung and kidney, are greater in the midterm fetus than those in the adult. DRT transcripts are detectable at low levels in a human teratocarcinoma cell line (NTera-2), but its expression is greatly increased after the NTera-2 cells are induced to become postmitotic neurons (NTera-2N) by retinoic acid treatment. These data suggest that DRT plays a part in human neurogenesis. A large number of tumor cell lines derived from neuroectoderm express DRT transcripts, including 12 neuroblastomas, two medulloblastomas, one primitive neuroectodermal tumor and six small cell lung carcinomas (SCLC). Interestingly, several neuroblastoma cell lines with 1p deletion and one SCLC cell line express DRT transcripts of aberrant size (i.e. 3, 6 and 8 kb) in addition to those found in normal tissues. We mapped the DRT gene to human chromosome 1p35-1p36.1 by PCR screening of human-rodent somatic cell hybrid panels and by fluorescence in situ hybridization. As the distal end of chromosome 1p is often deleted in neuroblastomas and altered in some cases in SCLCs, these chromosomal abnormalities may have resulted in the generation of aberrant size transcripts. Thus, the DRT gene may play a part in neuroblastoma and SCLC tumorigenesis.

GM1 ganglioside administration partially counteracts the morphological changes associated with haloperidol treatment within the dorsal striatum of the rat

Haloperidol, a typical antipsychotic drug, causes an increase in the mean percentage of synapses within the situation containing a discontinuous, or perforated, postsynaptic density (PSD) following 1 month of treatment (Meshul et al. 1994). This effect is not observed with the atypical antipsychotic drug, clozapine, following subchronic administration (Meshul et al. 1992a). This morphological change is also associated with an increase in the density of dopamine D2 receptors. The synapses containing the perforated PSD are asymmetrical and the nerve terminals contain the neurotransmitter, glutamate, as demonstrated by immunocytochemistry. We have also shown that subchronic treatment with haloperidol (0.5 mg/kg per day, 30 days) results in a decrease in the density of glutamate immunoreactivity within asymmetric nerve terminals associated with perforated and non-perforated PSDs (Meshul and Tan 1994). This could be due to an increase in glutamate release, perhaps due to activation of corticostriatal synapses. Agnati et el. (1983a) reported that administration of GM1 ganglioside blocks the increase in dopamine D2 receptors following haloperidol treatment. GM1 has also been shown to attenuate the release of glutamate (Nicoletti et al. 1989). In order to determine if similar treatment with ganglioside could block the haloperidol-induced ultrastructural changes notes above, rats were co-administered GM1 (10 mg/kg per day) and haloperidol (0.5 mg/kg per day) for 30 days. We report that GM1 blocked the haloperidol-induced increase in striatal asymmetric synapses containing a perforated PSD, but had no effect on the increase in dopamine D2 receptors or the decrease in nerve terminal glutamate immunoreactivity. GM1, either alone or co-administered with haloperidol, also caused a small, but significant, increase in the density of all asymmetric synapses within the striatum. It is possible that the effect of GM1 in attenuating the haloperidol-induced change in glutamate synapses with perforated PSDs is primarily postsynaptic, since GM1 did not block the change in density of glutamate immunoreactivity within asymmetric nerve terminals.

Immunosuppression by FK506 markedly prolongs expression of adenovirus-delivered transgene in skeletal muscles of adult dystrophic [mdx] mice

Adenovirus-mediated gene transfer into skeletal muscles of adult immune competent animals has been limited by the fact that a cellular immune attack of the host against transduced muscle fibers prevented long-term transgene expression. In this study we treated adult dystrophic [mdx] mice with daily subcutaneous injections of the immunosuppressive drug FK506 (tacrolimus) over 10 and 30 days after adenovirus-mediated reporter gene transfer and compared the transduction level to saline-injected controls. After 30 days, transgene expression was no longer demonstrable in the control group, whereas it remained at about 70% of the 10-day transduction value in the FK506 treated group. In addition, we demonstrated a reduction in the number of CD3 and CD8 positive T-lymphocytes in the muscles of the immunosuppressed group compared to controls.

Laparoscopic Nissen fundoplication is a satisfactory alternative to long-term omeprazole therapy

A total of 168 patients with proven gastro-oesophageal reflux disease (GORD) receiving long-term medical therapy underwent laparoscopic Nissen fundoplication. The operation was converted to open fundoplication in four patients. All patients reported complete (92.3 per cent) or partial (7.7 per cent) relief of reflux symptoms 1 month after surgery. There were no associated deaths and the perioperative complication rate was 8.9 per cent. The mean(s.e.m.) length of operating time was 69.9(2.4) min and mean(s.e.m.) hospital stay 2.7(0.1) days. Symptom score assessment, 24-h oesophageal pH recording and lower oesophageal sphincter pressure showed significant (P < 0.0001) improvement 6 months after surgery in 85 evaluable patients. Before operation 37.5 per cent of the patients were considered symptomatically controlled on omeprazole and had excellent symptom control after surgery. This initial experience suggests that laparoscopic Nissen fundoplication is a safe and effective treatment for patients with GORD requiring long-term medication.

Insulin-like growth factor-I is related to glycemic control in children and adolescents with newly diagnosed insulin-dependent diabetes

To address the relationship of insulin-like growth factor-I (IGF-I) to diabetes control, we determined IGF-I levels in 137 subjects age 17 yr and younger with recently diagnosed insulin-dependent diabetes mellitus in a population-based cohort study between 3 and 11 months after diagnosis (mean 4.9 months). Initial determinations of IGF-I, 24-h urine C-peptide and microalbuminuria, age, sex, height, weight, body mass index, pubertal stage, and glycosylated hemoglobin (GHb) were obtained. IGF-I levels ranged from 11-439 ng/mL, were strongly related to age (r = 0.74, P < 0.001), and were higher in females than males at any given age (P < 0.01). IGF-I was inversely related to GHb (partial r = -0.43, P < 0.001) after adjustment for sex and age. The relationship between IGF-I and GHb did not change between age groups (< 6, 6-9, > or = 10 yr of age; P = 0.50), and it did not change between prepubertal and pubertal subjects (P = 0.95). IGF-I was not related to 24-h urine C-peptide or microalbuminuria. These results suggest that lower IGF-I levels are related to poorer metabolic control of diabetes in the period following insulin-dependent diabetes mellitus diagnosis in all young persons regardless of age or pubertal status.

A region of consistent deletion in neuroblastoma maps within human chromosome 1p36.2-36.3

Deletion of the short arm of human chromosome 1 is the most common cytogenetic abnormality observed in neuroblastoma. To characterize the region of consistent deletion, we performed loss of heterozygosity (LOH) studies on 122 neuroblastoma tumor samples with 30 distal chromosome 1p polymorphisms. LOH was detected in 32 of the 122 tumors (26%). A single region of LOH, marked distally by D1Z2 and proximally by D1S228, was detected in all tumors demonstrating loss. Also, cells from a patient with a constitutional deletion of 1p36, and from a neuroblastoma cell line with a small 1p36 deletion, were analyzed by fluorescence in situ hybridization. Cells from both sources had interstitial deletions of 1p36.2-36.3 which overlapped the consensus region of LOH defined by the tumors. Interstitial deletion in the constitutional case was confirmed by allelic loss studies using the panel of polymorphic markers. Four proposed candidate genes--DAN, ID3 (heir-1), CDC2L1 (p58), and TNFR2--were shown to lie outside of the consensus region of allelic loss, as defined by the above deletions. These results more precisely define the location of a neuroblastoma suppressor gene within 1p36.2-36.3, eliminating 33 centimorgans of proximal 1p36 from consideration. Furthermore, a consensus region of loss, which excludes the four leading candidate genes, was found in all tumors with 1p36 LOH.

Papilloedema and lymphocytic meningitis in a 68 year old man

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A European exchange scheme for junior doctors in internal medicine 1977-91: experiences of participants and organisers

A retrospective survey was undertaken of the participants in and the organisers of an exchange scheme for junior physicians which has operated since 1977 between leading hospitals in countries of the European Community and Switzerland. The exchange has clinical, research, educational and cultural objectives and the survey sought to record the experiences of participants and their chiefs of service and note the strengths and weaknesses of the scheme as well as problems encountered with it. Overall, the participants' reports of their experiences of the scheme were favourable. Chiefs of host departments were enthusiastic about the interaction between participants and the host institutions. The impact of the programme on the junior doctors' educational and career development was variable though generally positive; major career changes were rare, the common pattern being one of helpful focusing of career intentions. Problems were relatively infrequent, mostly related to poor briefing, finances and bureaucracy. Few general international differences of experience of the scheme emerged.

Initial report of a genome search for the affective disorder predisposition gene in the old order Amish pedigrees: chromosomes 1 and 11

Family data have suggested that some forms of major affective disorder are genetic. Certain of the Old Order Amish pedigrees have a familial form of the disease. In this report we present the results of genetic analyses under autosomal dominant mode of transmission with reduced penetrance and three different disease hierarchies. The pedigrees were genotyped with 28 markers from chromosome 1 and 23 markers from chromosomes 11. None of the markers result in a significantly positive lod score.

Testing the role of p53 in the expression of genetic instability and apoptosis in ataxia-telangiectasia

We have obtained initial evidence supporting a new model for the human disease ataxia-telangiectasia (A-T), in which the A-T and p53 genes play crucial roles in a signal transduction network that activates multiple cellular functions in response to DNA damage. Three of the model's predictions were tested. (1) Disrupting cell cycle checkpoints should increase spontaneous rates in normal cells. In order to interfere with the G1/S checkpoint, we transfected a normal cell line with vectors expressing either a dominant-negative p53ala143 mutant or a human papilloma virus E6 gene. These transformants showed 10-80-fold elevations in spontaneous recombination rates when compared with their parent. (2) A-T cells should be sensitive to DNA damage-induced apoptosis. Widespread apoptosis was detectable in four A-T fibroblast lines, but not two control lines, beginning 24 h after exposure to X-rays or streptonigrin, but not UV. Streptonigrin also induced widespread apoptosis in A-T lymphoblasts but not in control lymphoblasts. (3) Disruption of p53 function in A-T cells should increase their mutagen resistance by interfering with apoptosis. Stable transfection of either the p53143ala or the HPV18 E6 construct was associated with acquisition of streptonigrin and radiation resistance, while transfection with the p53143ala construct did not affect the streptonigrin sensitivity of a control cell line.