Cloning and expression of the gene involved in Sanfilippo B syndrome (mucopolysaccharidosis III B)

Sanfilippo B syndrome is caused by a deficiency of alpha-N- acetylglucosaminidase, a lysosomal enzyme involved in the degradation of heparan sulphate. Accumulation of the substrate in lysosomes results in degeneration of the central nervous system with progressive dementia often combined with hyperactivity and aggressive behaviour. In order to clone the deficient gene, we purified the enzyme from human placenta and obtained amino acid sequence information. Alignment of one of the CNBr generated internal peptides to sequence from the database revealed the chromosomal location of the gene in the 5' upstream flanking region of the gene for 17-beta-hydroxysteroid-dehydrogenase at 17q21.1. The available DNA sequence was used to clone the cDNA coding for alpha-N- acetylglucosaminidase and analyse its gene structure. The gene is fully contained in the 5' upstream flanking region of the gene for 17-beta- hydroxysteroid-dehydrogenase and interrupted by five introns. The cDNA clone has a length of 2575 bp and encodes a protein of 743 amino acids. Chinese hamster ovary cells transfected with the cDNA construct show alpha-N-acetylglucosaminidase activity about 17-fold over background. This will allow correction studies with NAG deficient Sanfilippo B cell lines and facilitate the development of enzyme replacement therapy for these patients.      

New universal precaution aspiration tray

A new tray has been designed for use during procedures involving needles and other sharp objects. The tray includes a foam adhesive pad, marked into 10 sections, into which the sharp objects can be placed point first. After the procedure, the objects can be safely withdrawn by their handles and then discarded. The tray has been used in more than 250 procedures.     

Membrane properties of rat magnocellular neuroendocrine cells in vivo

Membrane properties of rat magnocellular neuroendocrine cells (MNCs) were examined during intracellular recordings in vivo. Current-clamp experiments revealed sustained outward rectification positive to −55 mV and transient outward rectification of depolarizing responses elicited from negative holding potentials. Trains of impulses were associated with a progressive increase of spike duration. Such features, which were not observed in neighboring non-neuroendocrine cells, are similar to those of MNCs in slices or explants of rat hypothalalus. In contrast, however, cells recorded in vivo were characterized by intense synaptic inhibition and a lower specific impedance than commonly observed from MNCs impaled in vitro.     

Comparison of deferral rates using a computerized versus written blood donor questionnaire: a randomized, cross-over study [ISRCTN84429599]

Background  

Self-administered computer-assisted blood donor screening strategies may elicit more accurate responses and improve the screening process.     

Successful treatment of refractory ascites in a child with transjugular intrahepatic portosystemic shunt

A 16-y-old boy who had undergone bone marrow transplantation for relapsed acute lymphoblastic leukaemia developed liver cirrhosis and refractory ascites, which did not respond to salt restriction, diuretics and abdominal paracentesis. Liver transplantation was not feasible because of poor nutritional status, pre-existing renal dysfunction and uncertainty about the prognosis of his leukaemia. The patient underwent a successful transjugular intrahepatic portosystemic shunt (TIPS), with immediate resolution of ascites, enabling cessation of diuretics and improvement in nutritional status. At 24 mo following TIPS there has been no re-accumulation of ascites. CONCLUSION: TIPS may have a role in the management of refractory ascites secondary to liver cirrhosis in selected children.     

埋没导引缝合针在双侧唇裂继发畸形修复中的应用

目的　探讨双侧唇裂继发畸形的解剖学修复。方法　采用埋没导引缝合针缝合法 ,对于引起畸形的主要因素 :鼻翼软骨向两侧移位 ,鼻降肌挛缩 ,口轮匝肌移位 ,鼻孔底瘢痕挛缩等进行彻底松解后 ,牢固准确地复位、固定 ,以恢复其正常的解剖关系。结果　自 1998年以来 ,共收治 2 6例双侧唇裂继发畸形患者 ,除 1例叉状皮瓣远端坏死外 ,余均顺利成功。随访 1～ 2年效果满意。结论　本手术不仅简单省时 ,而且能达到从解剖学角度修复畸形     

Use of an alpha-glucosidase inhibitor to maintain glucose homoeostasis during postprandial exercise in intensively treated Type 1 diabetic subjects.

AIM: We evaluated the effects of an alpha-glucosidase inhibitor, acarbose, on glucose homoeostasis during postprandial exercise in Type 1 diabetic subjects. METHODS: Seven Type 1 diabetic subjects with good glycaemic control on ultralente-regular insulin were randomized in a single blind cross-over study to acarbose 100 mg or placebo taken with a mixed meal (600 kcal, 75 g carbohydrates), followed 90 min later by 30 min of exercise at 50% maximum aerobic capacity. Glucose turnover was measured by tracer (d-[6,6,2H2]glucose) methodology, and intestinal glucose absorption was quantified using carbohydrate polymers labelled with [13C]glucose. RESULTS: Acarbose resulted in a significant decrease in the postprandial glycaemic rise (mean +/- SEM 2.9 +/- 0.6 vs. 5.0 +/- 0.7 mmol/l; P < 0.005) and in the glycaemic nadir during exercise (- 0.8 +/- 0.6 vs. 0.9 +/- 1.3 mmol/l below baseline; P < 0.05). Total glucose appearance increased similarly under the two treatments during the postprandial (27.0 vs. 27.9 micromol per kg per min) and exercise (33.9 vs. 33.5 micromol per kg per min) periods. Mean glucose absorption was significantly delayed by acarbose (7.8 vs. 10.2 micromol per kg per min; P < 0.02), but was compensated by the lack of postprandial suppression of hepatic glucose production (106% of basal hepatic glucose production vs. 81%; P < 0.006). Episodes of hypoglycaemia were no different (three vs. six). CONCLUSION: These results indicate that, in Type 1 diabetic subjects, acarbose results in a better glycaemic profile during postprandial exercise and suggest that it could lead to a lower risk of exercise-induced hypoglycaemia due to delayed glucose absorption and less suppression of hepatic glucose production.