Temperament in the rat: sex differences and hormonal influences on harm avoidance and novelty seeking

This study showed large and consistent individual differences in 64 rats (32 males) in the hole board and canopy test, which are considered to measure exploration and anxiety, respectively. Nonestrous females were more active than males and nose poked more in the hole board. In the canopy test, nonestrous females, compared with males, showed greater intraindividual variability in time spent outside the protective canopy. Estrous females spent significantly more time outside the canopy. Gonadectomy reduced nose poking in males and hole board locomotion in both sexes. Principal-components analysis disclosed 2 temperamental dimensions reflecting harm avoidance and novelty seeking. More males had high levels of psychometric harm avoidance, and fewer males than females had a low-harm-avoidance/high-novelty-seeking, sanguine profile.

Survival and differentiation of adult rat-derived neural progenitor cells transplanted to the striatum of hemiparkinsonian rats

We investigated the survival, distribution and differentiation capabilities of adult rat hippocampus-derived progenitor cells (AHPs) by grafting them into either the intact or dopamine (DA)-denervated adult rat striatum (ST). Furthermore, we tested the effects of the in vivo administration of retinoic acid (RA) on the differentiation of the grafted cells. AHPs, prelabeled in vitro with bromodeoxyuridine (BrdU) and primed with RA, were transplanted bilaterally into the ST of hemiparkinsonian rats. Twenty animals were divided in four groups: three groups received i.p. injections of RA (1.5 mg/kg/day) for 1, 2 or 4 weeks and one group received vehicle injections for 4 weeks. Approximately 60% of the implanted BrdU-immunoreactive (BrdU+) cells were present in either intact or lesioned ST after 5 weeks of transplantation, with a striking widespread radial distribution from the implantation site. The cells became morphologically integrated with the surrounding host tissue, with no evidence of tumor formation. Approximately 18% of the BrdU+ cells were immunoreactive for the glial precursor marker NG2 and occasionally BrdU+ cells co-expressed the neuronal marker TuJ1. This differentiation pattern was similar in the intact and DA-denervated ST. Although further research is needed to find more adequate methods to drive the differentiation of these cells toward the desired phenotypes, the survival, differentiation potential and widespread distribution throughout the ST observed in this study suggest that AHPs may be useful in treatment of degenerative disorders affecting the nervous system.

Managing antituberculosis drug therapy by therapeutic drug monitoring of rifampicin and isoniazid

BACKGROUND

Current therapeutic regimens with rifampicin and isoniazid have proven successful in treating tuberculosis, however, toxicity, therapeutic failure, relapse and multiple drug resistance are serious concerns. Optimizing drug dose using therapeutic drug monitoring (TDM) may be a better approach than administering therapy as a standard dose.

AIMS

To establish and evaluate a TDM service to optimize rifampicin and isoniazid therapy.

METHODS

A TDM service for rifampicin and isoniazid was established in November 1998. Drug concentration data were collected, with relevant information to interpret the results. The reason for the request, information on concomitant drug administration and a questionnaire to assess clinical response to the drug results were also obtained.

RESULTS

Ninety patient episodes were accepted for study. The rifampicin plasma concentrations showed significant scatter, with 46% of the rifampicin concentrations below the normal range and 2% above the normal range. Similarly, 48% of isoniazid concentrations were below the lower target of the normal range and 29% were above the upper normal limit. There was a greater proportion of isoniazid concentrations above the normal range in female patients.

CONCLUSION

Significant pharmacokinetic variability was observed for rifampicin and isoniazid in the patient population studied. Further, a substantial number of plasma concentrations fell outside the suggested normal range for both drugs. Isoniazid plasma concentrations were significantly higher in female patients compared with male patients. Despite these abnormal results, the dose of rifampicin and isoniazid was altered in only 17% of patients, however, many patients received follow-up education because of the drug result. The service was considered valuable by 83% of respondents to the questionnaire. While TDM of rifampicin and isoniazid is a valuable tool to optimize the dose of these drugs in some patients, there is an urgent need for concentration-effect studies and possibly education on the principles and practice of TDM for these drugs.

Spontaneous thoracic duct cyst

Spontaneous and asymptomatic supraclavicular thoracic duct cysts (lymphoceles ) are rare. Only five cases have been reported so far. They are more common after surgery or trauma and have been reported in the abdomen, mediastinum, pelvis and neck. They must be differentiated from other neck cysts as failure to recognise their attachment may result in the disastrous consequence of chylothorax. A high index of suspicion is necessary, and diagnosis usually can be established by fine-needle aspiration and suitable imaging. This case is reported along with a review of the literature and management options, including that of inadvertent damage to the thoracic duct.

Carbon monoxide poisoning and sensorineural hearing loss

Exposure to carbon monoxide is a well-recognized cause of morbidity and mortality. Both acute accidental poisoning and chronic exposure are associated with a range of adverse health effects. We report two cases of carbon monoxide poisoning with the associated phenomenon of sensorineural hearing loss. Although hearing loss as a result of acute carbon monoxide exposure has previously been described, here we emphasize the need to consider chronic exposure to carbon monoxide as a potentially reversible cause of sensorineural hearing loss if diagnosed and treated early.

Raised intracranial pressure and seizures in the neurological intensive care unit

BACKGROUND

The relationship between changes in intracranial pressure and incidence of subclinical seizures in patients requiring neurological intensive care is not fully understood. The aim of this study was to investigate if acute increases in intracranial pressure were accompanied by subclinical seizures.

METHODS

We prospectively studied 17 intensive care patients (11 male, aged 3-66 yr) who were selected from 85 patients requiring intracranial pressure measurement. Patients were selected to have a 30 min, 16-channel electroencephalogram (EEG) recorded when intracranial pressure remained increased despite preliminary treatments.

RESULTS

Diagnoses included head injury, intracranial haemorrhage, subarachnoid haemorrhage and sagittal sinus thrombosis. All patients had at least one acute episode of intracranial pressure increase. Pressures ranged from 90 to 440 mm H(2)O. Encephalopathic features (delta/theta rhythms and burst suppression) were noted on all EEGs. No seizure activity was recorded.

CONCLUSIONS

We conclude from this pilot study that seizures are an uncommon cause of acute raised intracranial pressure. To determine whether raised intracranial pressure causes seizures, long-term monitoring in a large cohort of intensive care patients would be necessary, studying patients with similar diagnoses and ages.

Heavy users of acute psychiatric beds: randomized controlled trial of enhanced community management in an outer London borough

BACKGROUND

Heavy users of psychiatric services, often defined as the population that uses the most beds, consume a large part of the resources used by the whole service, despite being relatively small in number. Any intervention that reduces heavy use is therefore likely to lead to significant savings, and enhancement of standard care using a form of intensive case management akin to assertive community treatment was thought to be a pragmatic strategy for testing in this group.

METHODS

The effectiveness of enhanced community management (ECM) was compared with standard care alone in heavy users, who represented the 10% of patients with the highest number of hospital admissions and occupied bed days over the previous 6.5 years in an outer London borough. One hundred and ninety-three patients were randomly assigned to ECM or standard care and their use of services was determined after 1 and 2 years, with assessments of costs, clinical symptoms, needs, and social function made before entry into the study and after 1 and 2 years.

RESULTS

Despite a 24 fold increase in community contacts in the study group, there were no significant differences between the two groups in any of the main outcome measures. Small savings on in-patient and day-hospital service costs were counterbalanced by the increased costs of outpatient and community care for the subjects assigned to ECM. Clinical outcome data derived from interviews in two-thirds of the subjects were similar in both groups.

CONCLUSIONS

Providing additional intensive community focused care to a group of heavy users of psychiatric in-patient services in an outer London borough does not lead to any important clinical gains or reduced costs of psychiatric care.

Posterior segment approach for subretinal transplantation or injection in the canine model

A posterior segment approach for cell transplantation or injection into the subretinal space of the dog has been developed. Controlled penetration to the subretinal space was achieved using a 29-gauge injection cannula, either blunted or with a 30 degrees sharpened bevel, and partially ensheathed with moveable plastic tubing. Depending on the injection volume used, the retina detached, and the fluid was reabsorbed within 1-3 weeks, although for smaller volumes the retina reattached within a matter of days. The optimal injection volume used was between 100 and 150 microl, or two injections of 55 microl each. By ophthalmoscopy following the surgery, it was possible to serially monitor the injection site and retinal bleb through fundus photography. Light microscopy demonstrates the distribution of stable, viable RPE cells in the subretinal space up to 6 months. The transplantation technique developed for the dog is atraumatic and free from any major surgical or clinical complications. It can be readily used to deliver cells or fluids to localized regions of the subretinal space.

Functional outcomes of orofacial myofunctional therapy in children with cerebral palsy

Though some anecdotal evidence supports the efficacy of orofacial myofunctional therapy in cerebral palsy and other disorders, controlled studies are very scant. This study was undertaken to examine the efficacy of orofacial myofunctional therapy in sixteen children diagnosed with spastic cerebral palsy. Following baseline measures, all children participated in a four-month therapy program, consisting of training the tongue, lips, and jaw muscles for adequate posturing and functioning. Post-therapy measures indicated significant improvement in functioning of lips, tongue, and jaw. Speech intelligibility of words also improved significantly as measured by two judges using a five-point rating scale. A significant correlation was found between tongue functioning and improvement in speech intelligibility; however no significant correlation was obtained between functioning of lips/jaw and speech intelligibility. Clinical implications regarding use of orofacial myofunctional therapy with cerebral palsied children are discussed.

Adenoviral vector-mediated beta-glucuronidase cDNA transfer to treat MPS VII RPE in vitro

PURPOSE

To develop an effective therapy for treating glycosaminoglycan (GAG) storage in mucopolysaccharidosis VII (MPS VII) retinal pigment epithelium (RPE) in vitro using adenoviral vector mediated human beta-glucuronidase cDNA (Ad-GUSB) transfer.

METHODS

Ad-GUSB was used to infect RPE at confluency. The transduction condition was optimized varying time of infection and number of infectious particles. The beta-glucuronidase (GUSB) activity was measured in transduced cells and media using a fluorogenic substrate. The GAG profiles were examined by metabolically labeling RPE with (35)Na(2)SO(4).

RESULTS

Transduced RPE, irrespective of species or disease status, expressed a high level of beta-glucuronidase. The expressed enzyme restored normal levels of GAGs in the RPE cells of homozygous affected MPS VII dogs by metabolizing stored GAGs. The over-expressed enzyme (>10 000 nmoles/hr/mg) failed to restore normal level of GAGs. A high level of GUSB expression was maintained in vitro at least nine weeks.

CONCLUSIONS

Adenoviral vector could mediate transfer of GUSB in MPS VII affected RPE and RPE of various species, and the expression was observed to be stable in vitro. However, controlled expression of GUSB was essential for the metabolism of stored GAGs to achieve normal levels.

A physician-pharmacist model for the surveillance of blood pressure in the community: a feasibility study

Hypertension is poorly managed. Hospital-based pharmacists working with physicians have been shown to improve the rate of achievement of "target" blood pressure in selected patients. It is unknown if such schemes can operate in the community and to what extent they would attract volunteers with poorly managed blood pressure. We assessed the feasibility of pharmacists to provide community-based, open-access, blood pressure monitoring. In addition, we describe the blood pressure profile of the group in comparison to that of the 1994 Health Survey of England (HSE). Pharmacists from six pharmacies were trained to deliver the service. Adults living within the postal districts of the pharmacies were invited, through an advertising campaign, to volunteer to have their blood pressure measured. Blood pressure data and information on treatment for hypertension and/or diabetes were collected on 263 registrants. Patients were advised to have their blood pressure managed by the general practitioner immediately (category 1), re-measured within 2-3 months (category 2) or in 12 months time (category 3). The mean (s.d.) blood pressure of patients in categories 1 (n = 16), 2 (n = 117) and 3 (n = 130) was 186(16)/97(29), 151(13)/94(9) and 139(22)/86(13) mm Hg respectively; P < 0.001. Ninety-one patients (35%) were in receipt of antihypertensive therapy. Forty-five percent of the treated group had controlled blood pressure (<160/95 mm Hg) compared with 30% in the HSE dataset. A large proportion of known hypertensive patients with poor blood pressure control who had visited their general practitioner within the previous 6 months were detected by the pharmacist-led service. Pharmacists operating an open-access blood pressure monitoring service may be of value in improving the management of hypertension.

Long-chain acyl-coenzyme A esters and fatty acids directly link metabolism to K(ATP) channels in the heart

ATP-sensitive K (K(ATP)) channels are inhibited by cytosolic ATP, a defining property that implicitly links these channels to cellular metabolism. Here we report a direct link between fatty acid metabolism and K(ATP) channels in cardiac muscle cells. Long-chain (LC) acyl-coenzyme A (CoA) esters are synthesized from fatty acids and serve as the principal metabolic substrates of the heart. We have studied the effects of LC acyl-CoA esters and LC fatty acids on K(ATP) channels of isolated guinea pig ventricular myocytes and compared them with the effects of phosphatidylinositol 4,5-bisphosphate (PIP(2)). Application of oleoyl-CoA (0.2 or 1 micromol/L), a naturally occurring acyl-CoA ester, to the cytosolic side of excised patches completely prevented rundown of K(ATP) channels, but not of Kir2 channels. The open probability of K(ATP) channels measured in the presence of oleoyl-CoA or PIP(2) was voltage dependent, increasing with depolarization. Oleoyl-CoA greatly reduced the ATP sensitivity of K(ATP) channels. At a concentration of 2 micromol/L, oleoyl-CoA increased the half-maximal inhibitory concentration of ATP >200-fold. The time course of the decrease in ATP sensitivity was much faster during application of oleoyl-CoA than during application of PIP(2). The effects of PIP(2), but not of oleoyl-CoA, were inhibited by increasing Ca(2+) to 1 mmol/L. Oleate (C18:1; 10 micromol/L), the precursor of oleoyl-CoA, inhibited K(ATP) channels activated by oleoyl-COA: Palmitoleoyl-CoA and palmitoleate (C16:1) exerted similar reciprocal effects. These findings indicate that LC fatty acids and their CoA-linked derivatives may be key physiological modulators of K(ATP) channel activity in the heart.

Gene therapy restores vision in a canine model of childhood blindness

The relationship between the neurosensory photoreceptors and the adjacent retinal pigment epithelium (RPE) controls not only normal retinal function, but also the pathogenesis of hereditary retinal degenerations. The molecular bases for both primary photoreceptor and RPE diseases that cause blindness have been identified. Gene therapy has been used successfully to slow degeneration in rodent models of primary photoreceptor diseases, but efficacy of gene therapy directed at photoreceptors and RPE in a large-animal model of human disease has not been reported. Here we study one of the most clinically severe retinal degenerations, Leber congenital amaurosis (LCA). LCA causes near total blindness in infancy and can result from mutations in RPE65 (LCA, type II; MIM 180069 and 204100). A naturally occurring animal model, the RPE65-/- dog, suffers from early and severe visual impairment similar to that seen in human LCA. We used a recombinant adeno-associated virus (AAV) carrying wild-type RPE65 (AAV-RPE65) to test the efficacy of gene therapy in this model. Our results indicate that visual function was restored in this large animal model of childhood blindness.

A randomized trial of nelfinavir, ritonavir, or delavirdine in combination with saquinavir-SGC and stavudine in treatment-experienced HIV-1-infected patients

PURPOSE

To evaluate the 24-week impact of saquinavir-enhancing antiretroviral therapy on viral replication in patients previously treated with nucleoside analogues with or without prior saquinavir hard-gel capsules (HGC).

METHOD

Patients were randomized in three groups to receive the following: Group 1-nelfinavir (750 mg tid), saquinavir soft-gel capsule (SGC) (800 mg tid), and stavudine (40 mg bid); Group II-ritonavir (400 mg bid), saquinavir-SGC (400 mg bid), and stavudine (40 mg bid); or Group III-delavirdine (400 mg tid), saquinavir-SGC (800 mg tid), and stavudine (40 mg bid). Viral loads, CD4 count, and safety were assessed over a 24-week period with an additional 6-month follow-up.

RESULTS

73 patients received randomized therapy; 14 of whom were SQV naïve, with a median baseline viral load of 3.6 log(10) and a CD4 count of 370 cells/mm(3). By 6 months, the median decreases in plasma viral loads were 0.26, 0.71, and 0.29 log(10) copies/mL for groups I, II, and III, respectively. The median increases in CD4 counts, for groups I, II, and III, were 52, 40, and 69 cells/mm(3) at 6 months, respectively. Changes in viral load and CD4 counts at 6 months and 1 year were not significantly different between the treatment groups. More patients discontinued therapy in the ritonavir arm (35%) for drug intolerance or toxicity compared to either the nelfinavir or delavirdine arms (15% and 5%, respectively). In a multivariate analysis, baseline viral load, younger age, and baseline saquinavir resistance were significantly associated with detectable viral load at 24 weeks.

CONCLUSION

The use of antiretroviral agents that pharmacokinetically boost saquinavir levels has a modest benefit in saquinavir-experienced patients.

Ataxia telangiectasia mutated is essential during adult neurogenesis

Ataxia telangiectasia (A-T) is an autosomal recessive disease characterized by normal brain development followed by progressive neurodegeneration. The gene mutated in A-T (ATM) is a serine protein kinase implicated in cell cycle regulation and DNA repair. The role of ATM in the brain and the consequences of its loss on neuronal survival remain unclear. We studied the role of ATM in adult neural progenitor cells in vivo and in vitro to define the role of ATM in dividing and postmitotic neural cells from Atm-deficient (Atm(-/-)) mice in a physiologic context. We demonstrate that ATM is an abundant protein in dividing neural progenitor cells but is markedly down-regulated as cells differentiate. In the absence of ATM, neural progenitor cells of the dentate gyrus show abnormally high rates of proliferation and genomic instability. Atm(-/-) cells in vivo, and in cell culture, show a blunted response to environmental stimuli that promote neural progenitor cell proliferation, survival, and differentiation along a neuronal lineage. This study defines a role for ATM during the process of neurogenesis, demonstrates that ATM is required for normal cell fate determination and neuronal survival both in vitro and in vivo, and points to a mechanism for neuronal cell loss in progressive neurodegenerative diseases.

A prodrug approach to the design of cRaf1 kinase inhibitors with improved cellular activity

Earlier we reported potent cRaf1 kinase inhibitors with a key acidic phenol pharmacophore that had, at best, adequate cellular efficacy. To improve the cellular potency, phenol isosteres and prodrugs were investigated. Many phenol isosteres were synthesized and tested, but failed to provide adequate enzyme potency. A prodrug approach resulted in a 2- to 17-fold improvement over the parent compound in cell-based efficacy.

Costs and characteristics of heavy inpatient service users in outer London

"Heavy users" is a new term often used to describe those who occupy a disproportionate number of psychiatric beds. In this study we identified the heaviest 10% (193) inpatient service users in one London borough over a 6 year period and compared these with a control group of 400 ordinary inpatient users. A weighting index was used to combine frequency of admission with duration. Heavy users were diagnostically and demographically similar to ordinary inpatient service users and only differed by their extensive use of services, about 3 times more than ordinary users in terms of health care costs, during the measured year. Their heavy use mainly depended on occupying hospital beds, and their use of outpatient, day patient and community services was relatively light.