The effect of oral folic acid upon plasma homocysteine, endothelial function and oxidative stress in patients with type 1 diabetes and microalbuminuria

AIMS

The purpose of this study was to investigate the effect of oral folic acid supplementation upon plasma homocysteine (HCY), endothelial function and oxidative stress on patients with type 1 diabetes and microalbuminuria to test the hypothesis that oral folic acid would lower plasma HCY and thereby improve endothelial function and reduce oxidant stress in this high-risk group of patients.

METHODS

We measured plasma HCY, forearm blood flow, total antioxidant status and whole blood glutathione at baseline and after 2 months treatment with oral folic acid or placebo in 16 patients with type 1 diabetes and microalbuminuria.

RESULTS

Plasma HCY fell by 25% in the folic acid group but there was no difference in endothelial function or markers of oxidant stress in the treatment group.

CONCLUSIONS

Oral folic acid supplementation successfully lowered plasma HCY levels in patients with type 1 diabetes and microalbuminuria, however this was not associated with improvements in endothelial function or markers of oxidant stress.

In vitro function of buffy coat-derived platelet concentrates stored for 9 days in CompoSol, PASII or 100% plasma in three different storage bags

BACKGROUND AND OBJECTIVES

The aim of the study was to compare the in vitro quality of buffy coat-derived platelet concentrates (PC) during extended storage in plasma or additive solution in three different storage bags.

MATERIALS AND METHODS

A pooled and split design was chosen so that identical PCs were produced in either 100% plasma, 70% PASII : 30% plasma or 70% CompoSol : 30% plasma (n = 6 each). This was repeated for three different manufacturers' platelet storage bags (Fresenius, Baxter and Pall). PCs were sampled on days 1, 5, 7 and 9 of storage and tested in vitro using a variety of tests of platelet function. For each bag type, storage in PASII or Composol was compared with plasma (data taken across the entire storage period), and differences occurring with time were analysed for all storage media.

RESULTS

The pH of all PCs was > 6.8 at day 9 of storage. In vitro platelet function, as assessed by markers of platelet activation and metabolism, of PCs stored in CompoSol appeared to be similar to that of PCs stored in plasma over 9 days of storage. In contrast, PCs stored in PASII tended to have significantly higher levels of platelet activation (almost a twofold increase in % platelets positive for CD62P by day 5) and lower hypotonic shock response (approximately 40%, by day 7) compared to either PCs stored in 100% plasma or 70% CompoSol. The magnitude of the differences observed between platelet storage media appeared to be dependent on the type of platelet storage bag with the highest degree of platelet activation and lowest hypotonic shock response values being observed in Fresenius bags in combination with PASII.

CONCLUSIONS

The maintenance of platelet function in vitro during extended storage of PCs in platelet additive solutions is dependent on the combination of type of additive solution and type of platelet storage bag. For all bag types studied, storage in PASII resulted in poorer platelet function in vitro.

33. How to steal a body

You are a medical student in 1820, training in anatomy has now become a prerequisite to graduation but there are limited cadavers available for dissection. Could you be a body snatcher? What about if you only took unclaimed bodies? What if you didn’t actually excavate, just helped drive the wagon? What would be your conditions before you would turn to a life of crime? Keep in mind that just by “borrowing” the occasional body you would provide yourself with ample opportunities to learn anatomy and also easily afford your tuition. If you do decide to go ahead and become a body snatcher you’re going to have to learn the classic modus operandi employed by the best in the business. First of all you want to do some daytime reconnaissance by attending the burial to see if any booby traps are being set for potential body snatchers. Next, you return at night with a wagon and drop two men off at the burial site. They then start digging a 3’X3’ hole until they hit the coffin. The body is carefully extracted and any identifying clothing or jewelry is removed and put back in the coffin before being reburied. Now you might be worried about retribution but you really don’t have much to fear. Townsfolk have been known to protest in front of medical schools but you’d have to deal with this even if you weren’t a body snatcher. If you end up going to court the worst that would happen is a fine that you could easily pay off by stealing another body or two. Highet MJ. 2005. Body snatching and grave robbing: bodies for science. History and Anthropology 2005; 16(4):415-440. MacGillivray R. Body snatching in Ontario. CBMH/BCHM 1988; 5:51-60. Ross I, Ross CU. Body snatching in 19th Century Britain: from exhumation to murder. British Journal of Law and Society 1979; 6(1):108-118.

Phase I trial of VNP40101M in children with recurrent brain tumors—A Pediatric Brain Tumor Consortium (PBTC) study

2059

Background: VNP40101M, a novel DNA alkylating agent and a potent inhibitor of alkylguanine alkyl transferase (AGT) in pre- clinical studies, was evaluated in a phase I study in children with recurrent brain tumors. Methods: VNP40101M was given intravenously (i.v) daily for 5 days q 6 weeks up to 8 cycles. Using the continual reassessment method, dose escalation was performed independently in pts stratified based on intensity of prior therapy (stratum I-less-heavily pre-treated; stratum II- heavily pre-treated). Dose limiting toxicities (DLTs) and responses were assessed at the end of the first and 2nd cycles of treatment, respectively. Correlative studies included pharmacokinetics and measurement of AGT activity in peripheral blood mononuclear cells (PBMC) before and after treatment. Results: 41 eligible pts (stratum I- 19, stratum II- 22; median age 9.3 yrs, range 0.9 to 21.5) were enrolled on this study. Dose levels (in mg/m2/day) evaluated in Stratum I were 45, 60, and 78 mg; In Stratum II 20, 30, 45, and 60 mg. DLT in evaluable pts was myelosuppression (grade IV neutropenia for > 7 days or any grade IV thrombocytopenia) and occurred in 4/16 pts in stratum I [45 mg (n=1/12), 60 mg (n=1/2), 78 mg (n= 2/2)] and 3/19 pts in stratum II [45 mg (n= 3/4), 60 mg (n=0/1), 30 mg (n= 0/12), and 20 mg (n= 0/2)] respectively. Other significant toxicities post first course included renal failure (n=2), pulmonary (n=2), and fatal infection (n=1). PK studies showed median (range) terminal half-life of 62 mins (7.3 to 522 min). The MTDs in stratum I and II were 45 mg/m2/day and 30 mg/m2/day daily for 5 days q 6 weeks, respectively. Objective responses were observed in one pt each with brain stem glioma and medulloblastoma respectively. PBMC AGT levels did not decrease following VNP40101M treatment. Conclusions: The recommended pediatric phase II dose of VNP40101M given i.v daily for 5 days q 6 weeks is 45 mg/m2/day in less-heavily treated and 30 mg/m2/day in heavily treated pts.

[Table: see text]

Accuracy of Cochlear Implant Recipients on Pitch Perception, Melody Recognition, and Speech Reception in Noise

OBJECTIVE

The purposes of this study were to (a) examine the accuracy of cochlear implant recipients who use different types of devices and signal processing strategies on pitch ranking as a function of size of interval and frequency range and (b) to examine the relations between this pitch perception measure and demographic variables, melody recognition, and speech reception in background noise.

DESIGN

One hundred fourteen cochlear implant users and 21 normal-hearing adults were tested on a pitch discrimination task (pitch ranking) that required them to determine direction of pitch change as a function of base frequency and interval size. Three groups were tested: (a) long electrode cochlear implant users (N = 101); (b) short electrode users that received acoustic plus electrical stimulation (A+E) (N = 13); and (c) a normal-hearing (NH) comparison group (N = 21). Pitch ranking was tested at standard frequencies of 131 to 1048 Hz, and the size of the pitch-change intervals ranged from 1 to 4 semitones. A generalized linear mixed model (GLMM) was fit to predict pitch ranking and to determine if group differences exist as a function of base frequency and interval size. Overall significance effects were measured with Chi-square tests and individual effects were measured with t-tests. Pitch ranking accuracy was correlated with demographic measures (age at time of testing, length of profound deafness, months of implant use), frequency difference limens, familiar melody recognition, and two measures of speech reception in noise.

RESULTS

The long electrode recipients performed significantly poorer on pitch discrimination than the NH and A+E group. The A+E users performed similarly to the NH listeners as a function of interval size in the lower base frequency range, but their pitch discrimination scores deteriorated slightly in the higher frequency range. The long electrode recipients, although less accurate than participants in the NH and A+E groups, tended to perform with greater accuracy within the higher frequency range. There were statistically significant correlations between pitch ranking and familiar melody recognition as well as with pure-tone frequency difference limens at 200 and 400 Hz.

CONCLUSIONS

Low-frequency acoustic hearing improves pitch discrimination as compared with traditional, electric-only cochlear implants. These findings have implications for musical tasks such as familiar melody recognition.

Tailored interventions based on sputum eosinophils versus clinical symptoms for asthma in children and adults

BACKGROUND

Asthma severity and control can be measured both subjectively and objectively. Sputum analysis for evaluation of percentage of sputum eosinophilia directly measures airway inflammation, and is one method of objectively monitoring asthma. Interventions for asthma therapies have been traditionally based on symptoms and spirometry.

OBJECTIVES

To evaluate the efficacy of tailoring asthma interventions based on sputum analysis in comparison to clinical symptoms (with or without spirometry/peak flow) for asthma related outcomes in children and adults.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register of Trials, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and reference lists of articles. The last search was on 31 October 2006.

SELECTION CRITERIA

All randomised controlled comparisons of adjustment of asthma therapy based on sputum eosinophils compared to traditional methods (primarily clinical symptoms and spirometry/peak flow).

DATA COLLECTION AND ANALYSIS

Results of searches were reviewed against pre-determined criteria for inclusion. Three sets of reviewers selected relevant studies. Two review authors independently assessed trial quality extracted data. Authors were contacted for further information but none were received. Data was analysed as "treatment received" and sensitivity analyses performed.

MAIN RESULTS

Three adult studies were included; these studies were clinically and methodologically heterogenous (use of medications, cut off for percentage of sputum eosinophils and definition of asthma exacerbation). There were no eligible paediatric studies. Of 246 participants randomised, 221 completed the trials. In the meta-analysis, a significant reduction in number of participants who had one or more asthma exacerbations occurred when treatment was based on sputum eosinophils in comparison to clinical symptoms; pooled odds ratio (OR) was 0.49 (95% CI 0.28 to 0.87); number needed to treat to benefit (NNTB) was 6 (95% CI 4 to 32). There were also differences between groups in the rate of exacerbation (any exacerbation per year) and severity of exacerbations defined by requirement for use of oral corticosteroids but the reduction in hospitalisations was not statistically significant. Data for clinical symptoms, quality of life and spirometry were not significantly different between groups. The mean dose of inhaled corticosteroids per day was similar in both groups and no adverse events were reported. However sputum induction was not always possible.

AUTHORS' CONCLUSIONS

Tailored asthma interventions based on sputum eosinophils is beneficial in reducing the frequency of asthma exacerbations in adults with asthma. This review supports the use of sputum eosinophils to tailor asthma therapy for adults with frequent exacerbations and severe asthma. Further studies need to be undertaken to strengthen these results and no conclusion can be drawn for children with asthma.

Clinical correlates of mitochondrial function in Huntington's disease muscle

Huntington's disease (HD) is caused by an abnormally expanded CAG repeat in the IT-15 gene, which encodes a widely expressed protein called huntingtin. Abnormalities of mitochondrial respiratory chain function, specifically complex II/III, have been identified in HD striatum and defects of energy metabolism have been demonstrated in vivo in skeletal muscle in both symptomatic and presymptomatic HD patients. We have investigated respiratory chain function using histochemical and biochemical methods in HD skeletal muscle from 12 patients and compared these with 12 age and sex-matched controls. The data from the HD patients were related to clinical parameters of HD including the Unified Huntington's Disease Rating Scale (UHDRS). There were positive correlations between CAG repeat years (a product of CAG repeat length and age) and both motor (P < 0.002) and cognitive (P < 0.01) scores of the UHDRS. There was no significant difference in the activities of complexes I to IV compared to age-matched controls. However, there were significant correlations for individual HD complex II/III activities with disease duration (P = 0.017), repeat years (P = 0.032), and cognitive scores (P = 0.019). There was also evidence from ultrastructural studies that inclusion formation may occur in HD muscle. These results provide additional evidence that mutant huntingtin influences mitochondrial complex II/III function in non-neuronal tissue (skeletal muscle) and suggest that muscle may be a potential marker of disease progression in HD.

Plasma homocysteine, oxidative stress and endothelial function in patients with Type 1 diabetes mellitus and microalbuminuria

AIMS

The purpose of this study was to examine the associations between endothelial function, plasma homocysteine and oxidative stress in patients with Type 1 diabetes mellitus (DM) and microalbuminuria compared with DM patients with normoalbuminuria and non-diabetic control subjects. We wished to test the hypothesis that increased cardiovascular risk in patients with Type 1 diabetes and microalbuminuria may be in part as a result of hyperhomocysteinaemia-mediated oxidative stress leading to impaired endothelial function.

METHODS

We measured forearm blood flow, total plasma homocysteine, total antioxidant status (TAOS) and whole blood glutathione in 31 DM patients, 16 with microalbuminuria and 15 with normoalbuminuria, and 15 non-diabetic control subjects.

RESULTS

Plasma homocysteine levels were significantly higher in the microalbuminuric diabetic patients compared with the normoalbuminuric patients and the control subjects. TAOS was significantly lower in the micoalbuminuric and normoalbuminuric diabetic patients compared with the control subjects, although TAOS levels were similar in both groups of diabetic patients. There was no difference in forearm blood flow between the groups and no association between measured endothelial function and antioxidant defence/oxidative stress and homocysteine in each group. There was no association between plasma total homocysteine and TAOS or whole blood glutathione within the groups.

CONCLUSIONS

We have found mild hyperhomocysteinaemia in microalbuminuric DM patients compared with normoalbuminuric DM patients and non-diabetic subjects and some evidence for reduced antioxidant defence in DM patients. These findings add to our understanding of the increased risk of vascular disease in patients with Type 1 diabetes.

Music Perception with Cochlear Implants and Residual Hearing

AIM

The aims of this study were to examine the music perception abilities of Cochlear Nucleus Hybrid (acoustic plus electric stimulation) cochlear implant (CI) recipients and to compare their performance with that of normal-hearing (NH) adults and CI recipients using conventional long-electrode (LE) devices (Advanced Bionics: 90K, Clarion, CIIHF; Cochlear Corporation: CI24M, CI22, Contour; Ineraid). Hybrid CI recipients were compared with NH adults and LE CI recipients on recognition of (a) real-world melodies and (b) musical instruments.

PATIENTS AND METHODS

We tested 4 Hybrid CI recipients, 17 NH adults, and 39 LE CI recipients on open-set recognition of real-world songs presented with and without lyrics. We also tested 14 Hybrid CI recipients, 21 NH adults, and 174 LE CI recipients on closed-set recognition of 8 musical instruments playing a 7-note phrase.

RESULTS

On recognition of real-world songs, both the Hybrid recipients and NH listeners were significantly more accurate (p < 0.0001) than the LE CI recipients in the no lyrics condition, which required reliance on musical cues only. The LE group was significantly less accurate than either the Hybrid or NH group (p < 0.0001) on instrument recognition for low and high frequency ranges.

CONCLUSIONS

These results, while preliminary in nature, suggest that preservation of low-frequency acoustic hearing is important for perception of real-world musical stimuli.

Acoustic plus electric speech processing: preliminary results of a multicenter clinical trial of the Iowa/Nucleus Hybrid implant

AIM

This communication details the latest preliminary results from an ongoing multicenter single-subject design clinical trial of the Iowa/Nucleus Hybrid 10-mm cochlear implant. Selection criteria, surgical strategies used for hearing preservation, and the benefits of preserved residual low-frequency hearing, improved word understanding in noise, and music appreciation are described.

PATIENTS AND METHODS

The device has been implanted in 48 individuals with residual low-frequency hearing.

RESULTS

Hearing preservation has been accomplished in 46/48 subjects. Acoustic speech perception has also been preserved. Combined acoustic plus electric speech processing has enabled most of this group of volunteers to gain improved word understanding as compared to their preoperative hearing with bilateral hearing aids. A subset of subjects with 12 months or more experience demonstrates CNC word understanding continues to improve more than 24 months after implantation. Improved word understanding in noise is also a benefit of acoustic plus electric speech processing.

CONCLUSIONS

The improvement of speech in noise and melody recognition is linked to the ability to distinguish fine pitch differences as the result of preserved residual low-frequency acoustic hearing. Both of these measures are very important in real life to the hearing impaired. Preservation of residual low-frequency hearing should be considered when expanding candidate selection criteria for standard cochlear implants.

Using a cross-coil to reduce RF heating by an order of magnitude in triple-resonance multinuclear MAS at high fields

Four different coil designs for use with MAS in triple-resonance multi-nuclear experiments at high fields are compared, using a combination of finite element analysis (FEA) software and NMR experiments, with respect to RF field strength per unit power and relative sample heating, as governed by mean E/B(1) within the sample region. A commercial FEA package, Microwave Studio 5.1 by Computer Simulation Technology (CST) is shown to obtain remarkably accurate agreement with the experiments in Q(L), L, B, E, and mode frequencies in all cases. A simplified treatment of RF heating in NMR MAS samples is derived and shown to agree with the NMR experimental results within about 10% for two representative stator designs. The coil types studied include: (1) a variable-pitch solenoid outside a ceramic coilform, (2) a conventional solenoid very closely spaced to the MAS rotor, (3) a scroll coil, and (4) a segmented saddle cross coil (XC) for (1)H with an additional solenoid over it for the two lower-frequency channels. The XC/solenoid is shown to offer substantial advantages in reduced decoupler heating, improved S/N, and improved compatibility with multinuclear tuning and high-power decoupling. This seems largely because the division of labor between two orthogonal coils allows them each, and their associated circuitry, to be separately optimized for their respective regimes.

Using the UK primary care Quality and Outcomes Framework to audit health care equity: preliminary data on diabetes management

BACKGROUND

The incentivization of UK primary care through the Quality and Outcomes Framework (QOF) has released an unprecedented supply of data that in theory could aid health equity audit and reduce health inequalities. The current system allows for 'exception reporting' whereby patients can be excluded from calculation of payment for reasons such as failure to attend review. We speculated that such exclusions could be linked to socioeconomic deprivation.

METHODS

We assessed 'exception reporting' rates for 15 diabetes indicators using 2004/05 QOF data for 49 general practitioner (GP) practices in Brighton and Hove and related it to a deprivation ranking for each practice.

RESULTS

The standardized diabetes prevalence was 26% higher (P < 0.001) in the highest compared to the lowest quintile of deprivation. Correlations between 'exception reporting' and deprivation were seen for 10 of the 15 diabetes indicators (r = 0.20-0.41, P < 0.05). Practices with a more deprived patient population were more likely to report 'exceptions' for QOF indicators, although there was no such relationship with the achievement of QOF targets.

CONCLUSIONS

Strategies to reduce health inequalities need to take into account that high levels of exception reporting, particularly in practices with deprived populations, may be disguising unmet need in those populations.

Acceptability of low molecular weight heparin thromboprophylaxis for inpatients receiving palliative care: qualitative study

OBJECTIVE

To find out what inpatients with advanced cancer who are receiving palliative care think about the effect of thromoprophylaxis on overall quality of life.

DESIGN

Qualitative study using audiotaping of semistructured interviews.

SETTING

Regional cancer centre in Wales.

PARTICIPANTS

28 inpatients with advanced metastatic cancer receiving palliative care and low molecular weight heparin.

MAIN OUTCOME MEASURES

Recurring themes on the effect of thromboprophylaxis on overall quality of life.

RESULTS

Major emerging themes showed that patients knew about the risks of venous thromboembolism and the purpose of treatment with heparin. Media coverage had raised awareness about venous thromboembolism, and many had previous experience of thromboprophylaxis. All found low molecular weight heparin an acceptable intervention, and many said that it improved their quality of life by giving them a feeling of safety and reassurance. Antiembolic stockings were considered uncomfortable and had a negative impact on quality of life. Patients were concerned that because they had advanced disease they might not be eligible for thromboprophylaxis.

CONCLUSION

Low molecular weight heparin is acceptable to inpatients with advanced cancer receiving palliative care and has a positive impact on overall quality of life. Antiembolic stockings are an unacceptable intervention in this patient group. Guidelines on thromboprophylaxis are urgently needed for palliative care inpatient units and hospices.

Refining the diagnosis of mitochondrial HMG-CoA synthase deficiency

Mitochondrial HMG-CoA synthase deficiency is an inherited metabolic disorder caused by a defect in the enzyme that regulates the formation of ketone bodies. Patients present with hypoketotic hypoglycaemia, encephalopathy and hepatomegaly, usually precipitated by an intercurrent infection or prolonged fasting. The diagnosis may easily be missed as previously reported results of routine metabolic investigations, urinary organic acids and plasma acylcarnitines may be nonspecific or normal, and a high index of suspicion is required to proceed to further confirmatory tests. We describe a further acute case in which the combination of urinary organic acids, low free carnitine and changes in the plasma acylcarnitine profile on carnitine supplementation were very suggestive of a defect in ketone synthesis. The diagnosis of mitochondrial HMG-CoA synthase deficiency was confirmed on genotyping, revealing two novel mutations: c.614G > A (R188H) and c.971T > C (M307T). A further sibling, in whom the diagnosis had not been made acutely, was also found to be affected. The possible effects of these mutations on enzyme activity are discussed.