Characterisation, mutation detection, and association analysis of alternative promoters and 5' UTRs of the human dopamine D3 receptor gene in schizophrenia

The dopamine D(3) receptor gene (DRD3) is a candidate for a number of psychiatric conditions including schizophrenia, bipolar disorder and alcohol and drug abuse. Previous studies have reported associations between polymorphisms in DRD3 and these disorders, but these findings may have reflected linkage disequilibrium with pathogenic variants that are further upstream. We have isolated and sequenced approximately 9 kb of genomic sequence upstream of the human DRD3 translational start site. Using 5' RACE, we have identified within this region three additional exons and two putative promoter regions which show promoter activity in three different cell lines. A 5' UTR identified only in lymphoblasts is spread over three exons and is 353 bp long. A second 5' UTR, found in adult and fetal brain, lymphocytes, kidney and placenta is spread over two exons and is 516 bp long. A 260-bp sequence within this 9 kb corresponds to a previously reported EST, but corresponding mRNA could not be found in the tissues above. The EST, 5' UTRs and putative promoter regions have been analysed for polymorphisms, revealing 10 single nucleotide polymorphisms, seven of which were tested for association in a large sample of unrelated patients with schizophrenia and matched controls. No associations were observed with schizophrenia. In addition we failed to replicate previous findings of association with homozygosity of the Ser9Gly variant. The results from this study imply that neither the coding nor the regulatory region of DRD3 plays a major role in predisposition to schizophrenia.

Gamma knife radiosurgery for recurrent trigeminal neuralgia

Object. Pain may fail to respond or may recur after initial gamma knife radiosurgery (GKS) for trigeminal neuralgia (TN). The authors examined their experience with performing a second GKS procedure in these patients.

Methods. Twenty-nine patients underwent repeated GKS for TN at our institution between March 1997 and March 2002. Questionnaires were mailed to patients to assess the degree of their pain relief and the extent of facial numbness. Nineteen patients responded. All patients underwent repeated GKS involving a single 4-mm isocenter directed at the trigeminal nerve as it exited the brainstem (mean maximum dose 23.2 Gy). At a mean follow up of 13.5 months after the second procedure, 10 patients (53%) were pain free and medication free. Four patients (21%) were pain free but elected to continue medication in reduced dose, and two patients (11%) had incomplete but satisfactory pain control and were still taking medication. There was new-onset facial numbness in eight patients (42%), rated as tolerable in all instances.

Conclusions. Patients with facial numbness had a greater likelihood of being pain free than those with no sensory loss. The authors observed no cases of corneal anesthesia, keratitis, or deafferentation pain.

Pharmacokinetics and bioavailability of trimethoprim-sulfamethoxazole in alpacas

The pharmacokinetics and bioavailability of trimethoprim-sulfamethoxazole (TMP-SMX) were studied in six healthy male-castrate alpacas (Lama pacos) after intravenous (i.v.) or oral (p.o.) drug administration of 15 mg/kg TMP-SMX using a crossover design with a 2-week washout period. After 90 days one group (n = 3) was given a p.o. dose of 30 mg/kg TMP-SMX and the other group (n = 3) was given a p.o. dose of 60 mg/kg TMP-SMX. After i.v. administration of 15 mg/kg of TMP-SMX the mean initial plasma concentration (C0) was 10.75 +/- 2.12 microg/mL for trimethoprim (TMP) and 158.3 +/- 189.3 microg/mL for sulfamethoxazole (SMX). Elimination half-lives were 0.74 +/- 0.1 h for TMP and 2.2 +/- 0.6 h for SMX. The mean residence times were 1.45 +/- 0.72 h for TMP and 2.8 +/- 0.6 h for SMX. The areas under the respective concentration vs. time curves (AUC) were 2.49 +/- 1.62 microg h/mL for TMP and 124 +/- 60 microg h/mL for SMX. Total clearance (Clt) for TMP was 21.63 +/- 9.85 and 1.90 +/- 0.77 mL/min kg for SMX. The volume of distribution at steady state was 2.32 +/- 1.15 L/kg for TMP and 0.35 +/- 0.09 L/kg for SMX. After intragastric administration of 15, 30 and 60 mg/kg the peak concentration (Cmax) of SMX were 1.9 +/- 0.8, 2.6 +/- 0.4 and 2.8 +/- 0.7 microg/mL, respectively. The AUC was 9.1 +/- 5, 25.9 +/- 3.3 and 39.1 +/- 4.1 microg h/mL, respectively. Based upon these AUC values and correcting for dose, the respective bioavailabilities were 7.7, 10.5 and 7.94%. Trimethoprim was not detected in plasma after intragastric administration. These data demonstrate that therapeutic concentrations of TMP-SMX are not achieved after p.o. administration to alpacas.

[Human infertility: meiotic genes as potential candidates]

Up to now, the identification of gene mutations causing infertility in humans remains poorly investigated. Temporal progression through meiosis and meiosis specific genes had been extensively characterized in yeast. Recently some mammalian homologous were found. The molecular mechanisms regulating entry into and progression through meiosis in mammals are still unknown. However, disruption of some meiotic genes in mouse showed an essential role of them in meiotic chromosome synapsis and gametogenesis. Moreover, the phenotype of gonads in null mutant mice for some meiotic genes (failure to initiate or blockage in meiosis, lack of gametes or small size of gonads...) could be strikingly similar to clinical observations found in human infertility. The aim of this study was to identify putative mutations in 5 meiotic genes of several clinically well-characterized patients who present unexplained infertility (normal karyotype, women with premature ovarian failure, men with azospermia and without Y micro-deletion). For this purpose, the exons of these 5 genes (DMC1, SPO11, MSH4, MSH5, CCNA1) were all amplified by PCR with specific primers and each amplified-exon was sequenced. Sequences were aligned in comparison to the human corresponding gene available in Genbank. Many heterozygous mutations were found in different genes. Two homozygous mutations were found in MSH4 and DMC1 genes in a young man presenting a testis vanishing syndrome and a woman presenting a premature ovarian failure, respectively. Consequences of such mutations will be examined and verified in model organisms (yeast, mouse) to check the relevance of the mutations in clinical setting.

The cost effectiveness of a nurse-led shared-care prostate assessment clinic

OBJECTIVE

Nurse-led prostate clinics (NPCs) have proved to be a highly effective method of assessing patients with lower urinary tract symptoms (LUTS) and most urology units now run such clinics. However, it was not known whether they are cost-effective and this analysis ansWers that question.

PATIENTS AND METHODS

During one year, a trained urology nurse assessed 1,080 patients in our NPC following GP referral using a standard pro forma. Costs included those incurred for the salary of a grade D nurse at 30 min per patient, all investigations, indirect charges and overheads. This was compared to the cost of seeing all patients in clinic directly, either by a consultant, staff grade urologist or registrar. Of these 1,080 patients, 350 were sent back to their GPs after NPC assessment.

RESULTS

The NPC cost of 44.25 pounds per patient compared favourably with an average medical out-patient clinic cost of 50.46 pounds per patient, yielding an actual annual saving of 6,706.80 pounds. Since a third of the patients assessed in the NPC were sent directly back to primary care, saving the cost of a medical follow-up appointment, the true savings in secondary care were 17,661.00 pounds (50.46 x 350pounds), giving a total annual saving of 24,367.80 pounds.

CONCLUSIONS

A nurse-led shared-care prostate clinic is a cost effective, thorough and speedy method of assessing men presenting with suspected bladder outflow obstruction. The approach used has a wider generic, cost-benefit potential for the NHS.

Sensitivity of the Procleix HIV-1/HCV assay for detection of human immunodeficiency virus type 1 and hepatitis C virus RNA in a high-risk population

The Procleix HIV-1/HCV Assay is a high-throughput nucleic acid test for the simultaneous detection of human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) RNA during blood donor screening. This study evaluated the clinical sensitivity of the Procleix assay and assessed the assay's ability to identify HIV-1- and HCV-infected individuals undetected by standard serologic tests. Plasma samples were obtained prospectively from 539 individuals at high risk for HIV-1 and HCV infection at seven clinics affiliated with Johns Hopkins University. Samples were tested in the Procleix HIV-1/HCV Assay and, if reactive, were then tested in the Procleix HIV-1 and HCV discriminatory assays to differentiate the source of viral RNA positivity. Of these 539 subjects, 287 (53.2%) tested reactive in the Procleix HIV-1/HCV Assay. In discriminatory assay testing, 12 of 287 subjects (4.2%) were reactive for HIV-1 RNA only, 260 (90.6%) were reactive for HCV RNA only, and 11 (3.8%) were coinfected with HIV-1 and HCV. The clinical sensitivity for samples tested neat was 100% for HIV-1 and 99.3% for HCV. Three subjects with Procleix HCV reactive/seronegative results seroconverted upon follow-up and were confirmed as Procleix HCV yield cases. The Procleix HIV-1/HCV Assay is a highly sensitive test that detects ongoing and early HIV-1 and HCV infection in a significant number of subjects at high risk for these diseases. Confirmation of Procleix yield cases upon follow-up demonstrated the ability of the Procleix HIV-1/HCV Assay to detect the presence of HIV-1 and HCV in blood earlier than standard serologic tests.

Cooling abolishes neuronal network synchronization in rat hippocampal slices

PURPOSE

We sought to determine whether cooling brain tissue from 34 to 21 degrees C could abolish tetany-induced neuronal network synchronization (gamma oscillations) without blocking normal synaptic transmission.

METHODS

Intracellular and extracellular electrodes recorded activity in transverse hippocampal slices (450-500 microm) from Sprague-Dawley male rats, maintained in an air-fluid interface chamber. Gamma oscillations were evoked by afferent stimulation at 100 Hz for 200 ms. Baseline temperature in the recording chamber was 34 degrees C, reduced to 21 degrees C within 20 min.

RESULTS

Suprathreshold tetanic stimuli evoked membrane potential oscillations in the 40-Hz frequency range (n = 21). Gamma oscillations induced by tetanic stimulation were blocked by bicuculline, a gamma-aminobutyric acid (GABA)A-receptor antagonist. Cooling from 34 to 21 degrees C reversibly abolished gamma oscillations in all slices tested. Short, low-frequency discharges persisted after cooling in six of 14 slices. Single-pulse-evoked potentials, however, were preserved after cooling in all cases. Latency between stimulus and onset of gamma oscillation was increased with cooling. Frequency of oscillation was correlated with chamber cooling temperature (r = 0.77). Tetanic stimulation at high intensity elicited not only gamma oscillation, but also epileptiform bursts. Cooling dramatically attenuated gamma oscillation and abolished epileptiform bursts in a reversible manner.

CONCLUSIONS

Tetany-induced neuronal network synchronization by GABAA-sensitive gamma oscillations is abolished reversibly by cooling to temperatures that do not block excitatory synaptic transmission. Cooling also suppresses transition from gamma oscillation to ictal bursting at higher stimulus intensities. These findings suggest that cooling may disrupt network synchrony necessary for epileptiform activity.

Gene therapy for prostate cancer delivered by ovine adenovirus and mediated by purine nucleoside phosphorylase and fludarabine in mouse models

A gene-directed enzyme pro-drug therapy (GDEPT) based on purine nucleoside phosphorylase (PNP), that converts the prodrug, fludarabine to 2-fluoroadenine, has been described, but studies are limited compared with other GDEPTs. We investigated the in vitro and in vivo efficacies of PNP-GDEPT for treating androgen-independent (AI) prostate cancer. The PNP gene controlled by Rous sarcoma virus (RSV) constitutive promoter was delivered using a recombinant ovine adenovirus vector (OAdV220) that uses a different receptor from human adenovirus type 5. In vitro, OAdV220 provided increased transgene expression over a comparable human Ad5 vector in infected AI, murine RM1 prostate cancer cells. Subsequent in vivo testing was therefore confined to OAdV220. Transduction of RM1 cells with OAdV220 before implantation in immunocompetent mice dramatically inhibited subcutaneous (s.c.) tumor growth when fludarabine phosphate was administered systemically and increased mouse survival in a dose-dependent manner. In tumor-bearing C57BL/6 mice, a single intratumoral injection of OAdV220 produced detectable PNP activity for at least 6 days and with prodrug, retarded the growth of aggressive RM1 s.c. tumors by 35% at day 14. There was a consistent trend to reduction of pre-established intraprostatic RM1 tumors. A similar regimen induced significant therapeutic efficacy in human PC3 xenografts. Thus, ovine adenovirus-mediated GDEPT using the PNP system was effective in vivo against AI prostate cancers, the aggressive murine RM1, and the human PC3 lines. Methods that improve viral dissemination and stimulate the immune system in vivo may further improve efficacy.

Sequential extracts of human bone show differing collagen synthetic rates

Type I collagen is the major bone protein. Little is known quantitatively about human bone collagen synthesis in vivo, despite its importance for the understanding of bone formation and turnover. Our aim was to develop a method that could be used for the physiological and pathophysiological investigation of human bone collagen synthesis. We have carried out preliminary studies in patients undergoing hip replacement and in pigs to validate the use of the flooding dose method using (13)C- or (15)N-labelled proline and we have now refined our techniques to allow them to be used in a normal clinical or physiological setting. The results show that the application of a flooding dose causes bone free-proline labelling to equilibrate with that of blood in pigs and human beings, so that only 150 mg of bone will provide enough sample to prepare and measure the labelling of three fractions of bone collagen (dissolved in NaCl, acetic acid and pepsin/acetic acid) which have the same relative labelling (1.0:0.43:0.1) as measured by GC-combustion-isotope ratio MS. The rates of incorporation were substantially faster than in skeletal muscle samples taken at the same time. The results suggest that different fractions of human bone collagen turnover at markedly higher rates than had been previously considered. This approach should allow us to discover how growth and development, food, activity and drugs affect bone collagen turnover and to measure the effects on it of ageing and bone disease.

Evaluation of the HemoCue plasma haemoglobin analyser for assessing haemolysis in red cell concentrates during storage

BACKGROUND AND OBJECTIVES

To evaluate the HemoCue plasma haemoglobin (Hb) analyser for determining supernatant Hb in red cell concentrates (RCC) during storage and compare this to a spectrophotometric method.

MATERIALS AND METHODS

Samples from RCC (n = 20) at days 0, 7, 21, 35 and 42 of storage were tested by both methods for supernatant Hb.

RESULTS

Results are given as median with range. There was a significant correlation (r = 0.97, P < 0.0001), but statistically significant difference between the two methods (0.72 (0.36-2.77) spectrophotometric vs. 0.70 (0.3-2.6) g/l HemoCue). However, the mean bias was negligible at 0.06 g/l. The HemoCue method gave a interassay coefficient of variation of 5.6% at 1.2 g/l and was linear to at least 20 g/l.

CONCLUSION

The HemoCue plasma haemoglobin analyser is a simple, rapid, reliable and accurate method for the determination of supernatant Hb in RCC at the end of storage and compares well to established methods for supernatant Hb measurement.

HFE mutations in an inflammatory arthritis population

OBJECTIVES

To determine the value of screening patients with inflammatory arthritis for haemochromatosis-associated mutations in the HFE gene.

METHODS

We screened 1000 patients with inflammatory arthritis and 1000 controls for the HFE gene mutations that are associated with haemochromatosis. The arthritis patients were diagnosed between 1989 and 1995 and their blood DNA was archived as part of the Norfolk Arthritis Register project.

RESULTS

Five out of 1000 (0.005) patients in the arthritis group were homozygous for the HFE C282Y mutation. This frequency is the same as the frequency of 5/1000 (0.005) for C282Y homozygosity observed in the normal population. It is slightly above the predicted frequency of homozygosity of 0.0044 derived from the gene frequency in the normal population.

CONCLUSIONS

These data suggest that most of the C282Y homozygotes occurred in this arthritis group by chance and that their arthritis was incidental to their HFE genotype. This implies that screening for HFE mutations among patients with inflammatory arthritis would infrequently identify patients whose arthritis might benefit from additional treatment.

Quantitative measurement of spinal brace use and compliance in the treatment of adolescent idiopathic scoliosis

The objective measurement of compliance with spinal bracing in adolescents with idiopathic scoliosis (AIS) is fundamental in the validation of clinical trials of bracing effectiveness, and in helping clinicians better understand reasons behind poor compliance. Current technology has been developed and tested for discrete, reliable and objective measurement of the times of day a brace is worn and consistency in its use. TLSOs were instrumented with data loggers measuring temperature at the skin/brace interface at 16 minutes intervals over a period of 88 days; between routine follow up and without patient interference. 10 female patients (age 14 years, sd 1.1) with AIS using spinal bracing as part of their treatment regime took part in the study over 15 months. Skin/brace interface temperature during periods of wear in the UK was >30 degrees C, ambient 23 degrees C, sd 4. Compliance ranged from 8-90%, average 65%. Patients tended to over estimate their compliance by 150% (sd 50%). There was no significant difference between weekday and weekend compliance but wear patterns differed. Nightwear was significantly greater than daywear. Patients with very good compliance only removed their brace for washing or exercise periods but where poor compliance was evident, the brace was only worn sporadically during the day. Temperature provides a clear signal of brace use and can be used for long-term data logging using discrete instrumentation, providing a tool to help identify and understand the reasons behind poor compliance.

Basaloid/follicular hyperplasia overlying connective tissue/mesenchymal hamartomas simulating basal cell carcinomas

BACKGROUND

Basaloid hyperplasia has been described overlying dermatofibromas as well as in the epidermis overlying nevus sebaceus. Although the morphology of these areas may resemble that of basal cell carcinoma (BCC), in the majority of cases aggressive behavior of the proliferation is not seen. In fact, the basaloid proliferation often shows follicular differentiation and may be stimulated and maintained by its relationship with the underlying stromal cells.

OBJECTIVE

We wanted to determine whether immunohistochemical staining for antibodies, which may suggest differences in pathogenesis, were different in basaloid hyperplasia overlying connective tissue/mesenchymal hamartomas and BCC.

METHODS

We report 3 cases of connective tissue/mesenchymal hamartomas with overlying basaloid hyperplasia, in which the areas of the basaloid proliferation showed follicular differentiation. Immunohistochemical stains included Ber-EP4, PCNA, Ki-67, Bcl-2, p53, SM-Actin, CD31, factor XIIIa, KP-1, and CD34.

RESULTS

There was a diffuse positive reaction for Ber-EP4 in all specimens and there was increased nuclear staining for PCNA and Ki-67. There was focal cytoplasmic staining for Bcl-2 in the areas of basaloid hyperplasia. Immunohistochemical staining for p53 showed only scattered positive cells except in a small focus in the areas of basaloid hyperplasia. The connective tissue component of all lesions showed diffuse staining for CD34 surrounding areas of basaloid hyperplasia in the mesenchymal component as well as in abundant S-100(+) nerves.

CONCLUSION

The areas of basaloid hyperplasia in these hamartomas exhibited an immature phenotype similar to that seen in both BCCs and follicular tumors; however, the patterns of proliferation markers, p53, Bcl-2, and the surrounding stromal cell markers were similar to those of benign follicular tumors. Thus the staining pattern for this group of antibodies suggests that areas of basaloid hyperplasia are not BCC.

Predicted impact on Victoria's ambulance services of a new major trauma system

BACKGROUND

In 1999, a new major trauma system was proposed for the state of Victoria, Australia. The guidelines for the new system were aimed at delivering major trauma cases to definitive trauma care in the least time possible. The aim of the present study was to analyse the potential effect of this system on Victoria's ambulance services.

METHODS

The present study modelled the workload of major trauma cases in Victoria's ambulance service for one year pre- and post-introduction of the guidelines. Cases were analysed regarding whether their first hospital destination would change under the proposed guidelines, and, subsequently, whether they would require interhospital transport to a higher level trauma service. The impact on the ambulance services was modelled as annual changes in distances travelled due to predicted changes in hospital destinations.

RESULTS

Analysis of the predicted changes indicated that, in general, Victoria's metropolitan and rural road ambulance crews would not be greatly affected. However, some metropolitan road crews may have to travel extra distances for up to 110 cases per year. The major impact was on air retrieval crews, where the annual number of interhospital transfers is predicted to increase from approximately 150 to 330.

CONCLUSIONS

The present study demonstrated that most of the impact of a new trauma system on Victoria's ambulance services could be readily absorbed into the current workload. However, it also highlighted areas affected disproportionately within the ambulance services; in particular, air retrieval. Such studies are important to enable the effective implementation of new trauma systems.