International practices in the dietary management of fructose 1-6 biphosphatase deficiency.

BACKGROUND: In fructose 1,6 bisphosphatase (FBPase) deficiency, management aims to prevent hypoglycaemia and lactic acidosis by avoiding prolonged fasting, particularly during febrile illness. Although the need for an emergency regimen to avoid metabolic decompensation is well established at times of illness, there is uncertainty about the need for other dietary management strategies such as sucrose or fructose restriction. We assessed international differences in the dietary management of FBPase deficiency. METHODS: A cross-sectional questionnaire (13 questions) was emailed to all members of the Society for the Study of Inborn Errors of Metabolism (SSIEM) and a wide database of inherited metabolic disorder dietitians. RESULTS: Thirty-six centres reported the dietary prescriptions of 126 patients with FBPase deficiency. Patients' age at questionnaire completion was: 1-10y, 46% (n = 58), 11-16y, 21% (n = 27), and >16y, 33% (n = 41). Diagnostic age was: <1y, 36% (n = 46); 1-10y, 59% (n = 74); 11-16y, 3% (n = 4); and >16y, 2% (n = 2). Seventy-five per cent of centres advocated dietary restrictions. This included restriction of: high sucrose foods only (n = 7 centres, 19%); fruit and sugary foods (n = 4, 11%); fruit, vegetables and sugary foods (n = 13, 36%). Twenty-five per cent of centres (n = 9), advised no dietary restrictions when patients were well. A higher percentage of patients aged >16y rather than ≤16y were prescribed dietary restrictions: patients aged 1-10y, 67% (n = 39/58), 11-16y, 63% (n = 17/27) and >16y, 85% (n = 35/41). Patients classified as having a normal fasting tolerance increased with age from 30% in 1-10y, to 36% in 11-16y, and 58% in >16y, but it was unclear if fasting tolerance was biochemically proven. Twenty centres (56%) routinely prescribed uncooked cornstarch (UCCS) to limit overnight fasting in 47 patients regardless of their actual fasting tolerance (37%). All centres advocated an emergency regimen mainly based on glucose polymer for illness management. CONCLUSIONS: Although all patients were prescribed an emergency regimen for illness, use of sucrose and fructose restricted diets with UCCS supplementation varied widely. Restrictions did not relax with age. International guidelines are necessary to help direct future dietary management of FBPase deficiency.

A mechanistic investigation of the ruthenium porphyrin catalysed aziridination of olefins by aryl azides.

A mechanism for the aziridination of olefins by aryl azides (ArN3), promoted by ruthenium(ii) porphyrin complexes, is proposed on the basis of kinetic and theoretical studies. All the recorded data support the involvement of a mono-imido ruthenium complex as the active intermediate in the transfer of the nitrene moiety "ArN" to the olefin. The selectivity of the aziridination vs. the uncatalysed triazoline formation can be enhanced by fine-tuning the electronic features of the porphyrin ligand and the olefin/azide catalytic ratio. The DFT study highlights the importance of an accessible triplet ground state of the intermediate ruthenium mono-imido complex to allow the evolution of the aziridination process.

What Does The Blanking Period Blank?

In the management of paroxysmal, drug-refractory atrial fibrillation, pulmonary vein isolation has become a widely accepted treatment option. Currently, the arrhythmias following any form of myocardial ablation are not considered within a period of three months, known as "the blanking period". Although this period is authority- rather than evidence-based, it has become universally recognized. Indeed, several mechanisms play a role to determine the transient increased risk of post-procedural atrial tachyarrhythmias, occurring early after the procedure. Acute inflammatory changes may be responsible for immediate recurrence, since application of ablative energy on atrial tissue has a pro-inflammatory- and potentially arrhythmogenic effect. Atrial arrhythmias within the first 3 months after ablation are very common (35% to 65% of cases) and their significance as predictor of late recurrences is more significant during the first month. Furthermore, the current biological evidences indicate that the edema of the surrounding and ablated tissue is no longer present after 1 month. In our letter we advocate the reasons why a blanking period of four weeks should appear more reasonable, fostering its clinical importance and utility.

Unexplained hypoglycemia during continuous nocturnal gastric drip-feeding in a patient with glycogen storage disease type ia: is it a dumping-like syndrome?

A 5 years old boy affected with Glycogen Storage Disease type Ia (GSD-Ia) with previous optimal metabolic control developed severe erratic hypoglycemic episodes during continuous nocturnal gastric drip-feeding (CNGDF) administered by nasogastric tube. The episodes of hypoglycemia were not related to pump failure or human errors or wrong position of the tube in the gastrointestinal tract. Hyperinsulinism was also considered in this patient but it was excluded mainly because hypoglycemia was only nocturnal. Moreover, hypoglycemic episodes disappeared when CNGDF was stopped and he was fed with normal meals. The fact that hypoglycemia resolved after stopping CNGDF when nocturnal meals were introduced led us to hypothesize that CNGDF rich with simple carbohydrates might have been the cause of a sort of dumping-like syndrome. Dumping syndrome (DS) develops when a large amount of carbohydrate reaches the small intestine due to rapid gastric emptying (Tack et al. 2009; Hejazi et al. 2010). We suppose that CNGDF induced a disturbance of gastric motility with a gastric accumulation of fluids at a certain time of the night followed by a rapid voiding of the stomach leading to DS.

Human herpesvirus 7 is latent in gastric mucosa.

Chronic gastritis is associated frequently with persistent infection by Helicobacter pylori. However, not all patients with chronic gastritis have evidence of H. pylori infection, suggesting that other factors might contribute to the development of gastritis. The present study was undertaken to evaluate a possible etiologic role of human herpesvirus 7 (HHV-7). HHV-7 DNA was detected in about 80% of gastric biopsies, both in healthy mucosa from individuals without evidence of inflammation and in biopsies from patients with histologically confirmed chronic gastric inflammation. HHV-7 was present also in H. pylori negative samples, was associated specifically with gastric tissue and not with residual blood within the mucosa, and was present with high viral loads. HHV-7 DNA persisted in several patients also after remission of gastric inflammation and the viral presence did not correlate with specific symptoms. Analysis by RT-PCR showed that HHV-7 is transcriptionally inactive in chronic gastritis lesions. These observations show that gastric tissue represents a site of HHV-7 latent infection and a potential reservoir for viral reactivation.