Y+ and y+ L arginine transporters in neuronal cells expressing tyrosine hydroxylase

Arginine is a semi-essential amino acid that serves as sole substrate for enzymes involved in diverse cell processes including redox balance via nitric oxide synthase (NOS) and cell proliferation via arginase. Neurons that express nNOS require intracellular arginine to generate nitric oxide (NO). Using a TH+ neuronal cell line (CAD cells), we show that neuronal NO production is largely dependent on extracellular arginine. Although a small intracellular pool exists in CAD cells, the lack of mRNA for argininosuccinate synthase (AS), a rate limiting enzyme for arginine recycling, suggests that intracellular pools are not re-supplied by this mechanism in this sub-class of neurons. Rather, arginine is taken up from the extracellular media by two primary transport systems, the y+ and the y+ L systems. The expression of CAT1, CAT3, y+ LAT1 and y+ LAT2 mRNAs supports the presence of each system. CAD cell arginine transport is depressed by increased extracellular K+ levels and demonstrates that variations in membrane potential control neuronal arginine uptake. Short term exposure to the oxidizing agents, rotenone and Angeli's salt, but not FeSO4, increases arginine transport. The regulation of arginine uptake by physiological factors suggests that arginine supply adapts in a moment-to-moment fashion to the changing needs of the neuron.

Steroids, non-steroidal anti-inflammatory drugs, and sigmoid diverticular abscess perforation in rheumatic conditions

BACKGROUND

Corticosteroids and non-steroidal anti-inflammatory drugs are widely used for the treatment of rheumatic conditions, but their gastrointestinal damage significantly limits their use. Sigmoid diverticular abscess perforation (SDAP) is a very serious complication of diverticular disease.

OBJECTIVE

To determine the aetiology of large bowel SDAP in rheumatic conditions.

METHODS

64 patients with SPAD and 320 controls from a similar geographical area and of similar socioeconomic status were studied.

RESULTS

The results showed that independently of rheumatic diagnosis corticosteroid treatment is strongly associated with SDAP (OR 31.9 (95% CI 6.4 to 159.2; p<0.001), and non-steroidal anti-inflammatory drugs only weakly associated (OR 1.8 (95% CI 0.96 to 3.4); p = 0.069). A rheumatic diagnosis is also strongly associated with the development of SDAP (OR 3.5 (95% CI 1.9 to 6.7); p<0.001).

CONCLUSIONS

SDAP has serious implications for patients and consumes many healthcare resources. Patients and physicians should be warned of this potential complication.

Implantation of the Freehand System during initial rehabilitation using minimally invasive techniques

STUDY DESIGN

Series of four single subjects with and without intervention design.

OBJECTIVES

To describe a minimally invasive surgical technique used to implant the Freehand System during initial spinal cord injury (SCI) rehabilitation and to report rehabilitation outcomes of four recently injured adolescents using the Freehand System.

SETTING

Nonprofit children's hospital specializing in orthopedic and SCI care.

METHODS

Four subjects with C5 tetraplegia between 13 and 16 years of age and between 9 and 16 weeks following traumatic SCI underwent implantation of the Freehand System using minimally invasive surgical techniques. Outcomes on muscle strength, pinch force, hand function, performance of activities of daily living and satisfaction with and without the Freehand System were collected.

RESULTS

Each subject was successfully implanted with the Freehand System without perioperative complications and employed the Freehand System during therapy services and ad lib on the rehabilitation floor. At the last follow-up, every subject remained a motor candidate for the Freehand System. With the Freehand System, average lateral and palmar pinch force was 1.8 and 1.6 kg respectively; average pinch force without functional electrical stimulation (FES) was 0.29 kg. With the Freehand System, three subjects improved their rate of performance on The Upper Extremity Capabilities Questionnaire. All subjects increased their level of independence on The Quadriplegia Index of Function. On the Canadian Occupational Performance Measure (COPM) with the Freehand System, average performance and satisfaction scores improved for every patient. Three of the four subjects continued to use the system at home.

CONCLUSION

This case series demonstrates that the Freehand System can vastly improve hand function and performance of rehabilitation activities within days after a minimally invasive implant procedure during initial SCI rehabilitation. Satisfaction with the Freehand System beyond initial rehabilitation is evidenced by continued use at home.

Tuberculosis and HIV seroprevalence in Lambeth, Southwark and Lewisham, an area of South London

Since the mid-1980s the number of cases of TB notified within the U.K. has continued to rise although the contribution of HIV to this rise remains unclear. A 12-month prospective cohort study was conducted at chest and HIV clinics in four hospitals in Lambeth, Southwark and Lewisham (LSL), an area of South London, to determine the proportion of patients with culture-proven TB infected with HIV. Secondary aims were to determine the proportion of patients with TB and undiagnosed HIV at first presentation to chest clinics, to determine the proportion of patients presenting with TB as an AIDS defining illness (ADI) and to identify risk factors for co-infection with TB and HIV. In chest clinics, demographic data and left-over blood from patients aged 16 or over with culture-proven TB was collected, anonymised and HIV tested. In HIV clinics, demographic data on patients with TB already known to be HIV seropositive were also obtained. Twenty-one patients (13%, 95% CI-8-19%) of 159 with culture-proven TB were infected with HIV Four (3%) of 133 patients at first presentation to chest clinics had undiagnosed HIV; two were subsequently diagnosed. Of the 21 patients withTB and HIV, nine (43%) presented with TB as an ADI. Patients with TB and HIV were significantly more likely to be aged between 35 and 55 years compared to HIV seronegative patients [12/21 (57%) vs. 38/138 (28%), P=0.006]. None of the patients from the Indian Subcontinent were HIV seropositive [0/21 vs. 25/138 (18%), P=0.047]. At the present time, universal HIV testing of patients with culture-provenTB in chest clinics within the U.K. is unlikely to significantly reduce the number of patients with undiagnosed HIV.

Serum complexes of immunoglobulin A-alpha1 proteinase inhibitor in rheumatoid arthritis: association with current cigarette smoking and disease activity

OBJECTIVE

To investigate whether high levels of serum immunoglobulin A-alpha1 proteinase inhibitor (IgA-alpha1PI) complexes are primarily associated with cigarette smoking or the rheumatoid arthritis (RA) disease process itself.

METHODS

A case-control study consisting of 231 RA cases and 83 healthy hospital workers. A smoking history was taken for the study groups. The serum IgA-alpha1PI complex levels (arbitrary units, au) were determined using a sandwich ELISA. Erythrocyte sedimentation rate (ESR) and rheumatoidfactor (RF) measurements were recorded in each of the RA cases. The serum complex levels were compared between RA cases and controls matched for smoking history and between smokers and non-smokers in the RA cases and controls.

RESULTS

Mean serum IgA-alpha1PI complex levels were significantly higher in RA current smokers than in non-smoking RA patients (17.4 v 11.9 a.u., p = 0.0001). Similarly, mean serum complex levels were significantly higher in control current smokers than control non-smokers (18.8 v 11.5 a.u., p = 0.003). Seropositive RA cases had significantly higher complex levels than seronegative cases. Patients with erosive disease had higher levels than non-erosive patients, although significance was lost after correction for current smoking and RF positivity. There was an association between ESR and serum IgA-alpha1PI complex levels which was independent of current smoking. Overall, there was no significant difference in complex levels between RA cases and controls after correction for current smoking.

CONCLUSION

Raised serum IgA-alpha1PI complex levels are associated with current smoking in both RA and healthy controls. ESR levels in RA patients are also associated with serum complex levels independently of current smoking. Our data suggest that high IgA-alpha1PI complex levels can be generated either as a result of current smoking, or by an active disease process in RA patients.

Heavy cigarette smoking is strongly associated with rheumatoid arthritis (RA), particularly in patients without a family history of RA

OBJECTIVES

To investigate the potential relation between cumulative exposure to cigarette smoking in patients with or without rheumatoid arthritis (RA) and a positive family history of the disease.

METHODS

239 outpatient based patients with RA were compared with 239 controls matched for age, sex, and social class. A detailed smoking history was recorded and expressed as pack years smoked. Conditional logistic regression was used to calculate the association between RA and pack years smoked. The patients with RA were also interviewed about a family history of disease and recorded as positive if a first or second degree relative had RA. The smoking history at the time of the study of the patients with RA with or without a family history of the disease was compared directly with that of their respective controls. Patients with RA with or without a family history of the disease were also compared retrospectively for current smoking at the time of disease onset.

RESULTS

An increasing association between increased pack years smoked and RA was found. There was a striking association between heavy cigarette smoking and RA. A history for 41-50 pack years smoked was associated with RA (odds ratio (OR) 13.54, 95% confidence interval (95% CI) 2.89 to 63.38; p<0.001). The association between ever having smoked and RA was modest (OR 1.81, CI 1.22 to 2.19; p=0.002). Furthermore, cigarette smoking in the patients with RA without a positive family history of RA was more prevalent than in the patients with a positive family history of RA for ever having smoked (72% v 54%; p=0.006), the number of pack years smoked (median 25.0 v 4.0; p<0.001), and for smoking at the time of disease onset (58% v 39%; p=0.003).

CONCLUSIONS

Heavy cigarette smoking, but not smoking itself, is strongly associated with RA requiring hospital follow up and is markedly more prevalent in patients with RA without a family history of RA.

Implementation of antithrombotic management in atrial fibrillation

The aim of the study was to assess the extent to which published recommendations on the antithrombotic management of atrial fibrillation had been adopted into clinical practice in a busy district general hospital, and the impact of clinical audit on subsequent management. In the initial audit, 185 consecutive patients with atrial fibrillation were studied using their case notes to identify any further clinical risk factors for stroke. A management algorithm stratified patients with atrial fibrillation into high, moderate, or low risk of stroke according to the individual stroke risk factors. For patients at high risk, the correct treatment is warfarin unless there are specific contraindications. For patients at moderate risk, the correct management is aspirin unless there are specific contraindications. Patients at low risk should receive no thromboprophylaxis. The clinical risks of stroke and thromboprophylaxis on discharge from hospital were recorded. An extensive education programme on stroke prevention in atrial fibrillation was undertaken. Six months later a further 185 consecutive patients with atrial fibrillation were audited. Overall, a large proportion (306/370; 83%) of patients were at high risk of stroke. In the initial audit, antithrombotic management was correct in 89 patients (48%). In the follow up audit, antithrombotic management was correct in 135 patients (73%) (p < 0. 00001). If this improvement in management were extrapolated to all hospital patients in the United Kingdom, approximately 1400 strokes/year could be avoided. Despite broad consensus in recent publications, antithrombotic management of atrial fibrillation remains imperfect, with many patients exposed to unnecessarily high risk of stroke.

Old drug, new tricks: haloperidol inhibits secretion of proinflammatory cytokines

OBJECTIVES

It was noted that treatment of a patient with acute mania by haloperidol was associated with marked improvement in activity of rheumatoid arthritis. The objective of this study was to examine the effects of haloperidol on inflammatory cytokine release in vitro, as a potential mechanism to explain the in vivo anti-inflammatory effects of haloperidol.

METHODS

The effect of haloperidol on the production of inflammatory cytokines interleukin 1beta (IL1beta) and tumour necrosis factor alpha (TNFalpha) was measured in bacterial lipopolysaccharide stimulated whole blood cultures and on the promonocyte cell line THP-1, using commercial and in house enzyme linked immunosorbent assays to measure cytokine concentrations.

RESULTS

Haloperidol inhibited lipopolysaccharide stimulated production of both IL1beta and TNFalpha in vitro in a dose dependent manner and over a prolonged time period. Marked inhibition was seen over a range of concentrations of haloperidol from 0.5 microgram/ml to 50 microgram/ml, including those predicted to occur in the patient's blood.

CONCLUSIONS

Haloperidol treatment seemed to alleviate inflammation in rheumatoid arthritis. In vitro experiments would suggest that the mechanism is by direct inhibition of proinflammatory cytokine release. This phenomenon requires further investigation and may potentially lead to the development of novel treatment.