Effect of different levels of oral pyridoxine supplementation on plasma pyridoxal-5'-phosphate and pyridoxal levels and urinary vitamin B-6 excretion

Plasma pyridoxal-5'-phosphate and pyridoxal levels increased significantly (p less than 0.05) when single, oral bolus doses of pyridoxine were increased from 10 to 25 and from 25 to 50 mg in nine female volunteers. However, when the dose was increased to 100 mg, plasma pyridoxal-5'-phosphate levels did not differ significantly from those recorded after the 50 mg dose. Within 3 h plasma pyridoxal levels rose with a factor of 3.85 compared with the 50 mg dose but high pyridoxal levels were eliminated from the circulation. Renal clearance of pyridoxal remained a constant, low percentage (less than 2.0%) of each pyridoxine supplement in spite of the observed very high circulating pyridoxal levels. Pyridoxine supplementation is discussed in relation to circulating pyridoxal-5'-phosphate and pyridoxal availability for cellular metabolism.     

Prefrontal Responses during Proactive and Reactive Inhibition Are Differentially Impacted by Stress in Anorexia and Bulimia Nervosa

Binge eating is a distressing, transdiagnostic eating disorder symptom associated with impulsivity, particularly in negative mood states. Neuroimaging studies of bulimia nervosa (BN) report reduced activity in frontostriatal regions implicated in self-regulatory control, and an influential theory posits that binge eating results from self-regulation failures under stress. However, there is no direct evidence that psychological stress impairs self-regulation in binge-eating disorders, or that any such self-regulatory deficits generalize to binge eating in underweight individuals (i.e., anorexia nervosa bingeing/purging subtype; AN-BP). We therefore determined the effect of acute stress on inhibitory control in 85 women (BN, 33 women; AN-BP, 22 women; 30 control participants). Participants underwent repeated functional MRI scanning during performance of the Stop-signal anticipation task, a validated measure of proactive (i.e., anticipation of stopping) and reactive (outright stopping) inhibition. Neural and behavioral responses to induced stress and a control task were evaluated on 2 consecutive days. Women with BN had reduced proactive inhibition, while prefrontal responses were increased in both AN-BP and BN. Reactive inhibition was neurally and behaviorally intact in both diagnostic groups. Both AN-BP and BN groups showed distinct stress-induced changes in inferior and superior frontal activity during both proactive and reactive inhibition. However, task performance was unaffected by stress. These results offer novel evidence of reduced proactive inhibition in BN, yet inhibitory control deficits did not generalize to AN-BP. Our findings identify intriguing alterations of stress responses and inhibitory function associated with binge eating, but they counsel against stress-induced failures of inhibitory control as a comprehensive explanation for loss-of-control eating.SIGNIFICANCE STATEMENT Binge eating is a common psychiatric syndrome that feels uncontrollable to the sufferer. Theoretically, it has been related to reduced self-regulation under stress, but there remains no direct evidence for this link in binge-eating disorders. Here, we examined how experimentally induced stress affected response inhibition in control participants and women with anorexia nervosa and bulimia nervosa. Participants underwent repeated brain scanning under stressful and neutral conditions. Although patient groups had intact action cancellation, the slowing of motor responses was impaired in bulimia nervosa, even when the likelihood of having to stop increased. Stress altered brain responses for both forms of inhibition in both groups, yet performance remained unimpaired. These findings counsel against a simple model of stress-induced disinhibition as an adequate explanation for binge eating.     

Vitamin B6 nutritional status in asthma: the effect of theophylline therapy on plasma pyridoxal-5'-phosphate and pyridoxal levels

Plasma pyridoxal-5'-phosphate concentrations were significantly lower (p less than 0.001) in a group of 28 asthmatic women when compared to 33 controls. Plasma pyridoxal levels in the two groups were not different. Theophylline was administered to a group of 17 volunteers and resulted in large reductions in plasma pyridoxal-5'-phosphate levels, while plasma pyridoxal levels and urinary 4-pyridoxic acid excretion were unaffected by theophylline therapy. An in vitro study showed that theophylline did not interfere with the high performance liquid chromatography assay for pyridoxal-5'-phosphate, indicating that theophylline could affect liver metabolism of vitamin B6.     

The direct quantification in whole serum of HDL subfractions

A method is described for the direct electrophoretic separation in human serum of three HDL subfractions and the quantification of the cholesterol content of these by means of gas-liquid chromatography. Used in conjunction with established procedures for the separation of total HDL, VLDL and LDL on agarose gels (with gas-liquid chromatography quantification of cholesterol in each band) the procedure affords comprehensive information on lipoprotein metabolism in patients. Two technicians can process 10 samples per day, making the method suitable for semi-large scale screening of patients such as may occur in clinical trials or to evaluate in greater detail lipoprotein patterns of patients suspected of having lipoprotein abnormalities on the basis of simpler screening methods. Results obtaind by the method correlate well with those obtained by means of ultracentrifugation.     

Investigation into a school enterovirus outbreak using PCR detection and serotype identification based on the 5' non-coding region

A summer camp was followed by an outbreak of illness involving around 90 children. Investigations included individual questionnaires, inspection of the camp facilities, and laboratory analysis of water and clinical samples. Contamination of drinking and swimming water was demonstrated. An enterovirus was detected by polymerase chain reaction (PCR) and/or culture in 4/4 cerebrospinal fluid samples, 9/15 (60%) stool samples from symptomatic children and 2/9 (22%) stool samples from asymptomatic children. The virus was identified as an echovirus 3 by sequencing and phylogenetic analysis of a short 5' non-coding region (NCR) PCR product. Viruses from the outbreak clustered closely and an echovirus 3 from a temporally associated non-outbreak case could be readily distinguished. Despite the lack of a standardized approach, direct molecular detection and identification of enteroviruses is an efficient epidemiological tool. Here the 5'-NCR was successfully used for both detection and 'serotyping', and the close genetic relatedness of isolates was proven.     

Transverse arch hypoplasia may predispose patients to aneurysm formation after patch repair of aortic coarctation

BACKGROUND: Thoracic aortic aneurysm after patch repair of aortic coarctation is a potentially lethal complication. We hypothesized that transverse arch hypoplasia in association with patch repair of aortic coarctation predisposes aneurysm formation. METHODS: A retrospective analysis was performed on all patients undergoing isolated aortic coarctation repair at the University of Virginia Health Systems between 1970 and 1995. Of 244 repairs, 38 patients underwent patch repair. These 38 patients were divided into two groups. The aneurysm group (n = 15) had aortic aneurysms develop at the repair site, which required aneurysmectomy. The nonaneurysm group (n = 23) did not have any aneurysms develop. Univariate analysis and Fisher's exact text were used to identify factors that independently predict aneurysm formation. RESULTS: Univariate analysis demonstrated aortic arch hypoplasia associated with patch repair independently predicts future aneurysm formation (p < 0.01). Patients who had an aneurysm develop also had a similar incidence of bicuspid aortic valves, mild restenosis, and late hypertension compared with patients in the nonaneurysm group. CONCLUSIONS: Aneurysm formation after patch repair of aortic coarctation develops into a subgroup of patients. Aortic arch hypoplasia associated with coarctation independently predicts future aneurysm formation.     

Usage of antimicrobial agents in a private primary healthcare setting in South Africa

Objective The aim of this study was to investigate the prescribing of antimicrobials in a private primary healthcare setting in South Africa. Setting A group of private primary healthcare clinics in South Africa. Method A retrospective, drug utilisation study was conducted on nine clinics that were randomly selected from 33 clinics situated in different geographical areas of South Africa, and whose data were electronically available. Data were obtained from the central database of the private primary healthcare provider and extracted for the period January 1, to December 31, 2001. Key findings The study population consisted of the total patient population (n = 83 655) who visited the clinics during this one‐year period. The total number of medicine items prescribed was 515 976 at a total cost of R1 716 319 ($17 163). Of these, antimicrobials represented 18.69% (n = 96 421) of all medicine items prescribed at a cost of R1 045 108 ($10 451) (60.89%). Antimicrobials were prescribed during 72.72% of consultations at the nine clinics during the one‐year period. The antimicrobials most frequently prescribed were penicillins (38.17%) followed by sulphonamides (22.49%), antiprotozoals (9.88%) and tetracyclines (9.34%). The most common diagnoses for which antimicrobials were prescribed were viral influenza, upper respiratory tract infections, hypertension, acute bronchitis, and common cold. Conclusions The high percentage of antimicrobial prescribing obtained in this study could indicate excessive use of antimicrobials in the private primary healthcare setting. The prescribing of antimicrobials in respiratory tract infections could indicate overuse and inappropriate use of these agents. This could have an effect on the health of the patients needing care, and the general budget for healthcare services. It is recommended that further investigations on the prescribing protocols of antimicrobial usage be done.