Dental material artifacts on MR images

Magnetic resonance (MR) imaging of the head and neck is becoming an important aid in evaluating pathologic conditions of the brain, midface, and pharynx. Certain dental materials cause artifacts during MR imaging of the lower midface. These artifacts can obscure the normal anatomy. This study describes the degree of artifact production caused by various materials commonly used in dental restorations. Of the materials tested, those causing artifacts were made of stainless steel, such as orthodontic bands used for braces, and pins or posts that are commonly drilled into teeth to provide structure or stability before filling. Materials used as temporary or permanent fillings or crowns--such as amalgam, gold alloy, aluminum, microfilled resin, and polyvinyl acrylics--did not cause artifacts in the images.     

Comparison of pulmonary and pleural responses of rats and hamsters to inhaled refractory ceramic fibers

The present study was designed to determine whether pleural fiber burdens or subchronic pleural fibroproliferative and inflammatory changes can help explain the marked interspecies differences in pleural fibrosis and mesothelioma that are observed following long-term inhalation of RCF-1 ceramic fibers by rats and hamsters. Fischer 344 rats and Syrian golden hamsters were exposed to RCF-1 for 4 h per day, 5 days per week, for 12 consecutive weeks. Lung and pleural fiber burdens were characterized during and after exposure. For all time points, approximately 67% of fibers associated with lung tissues from both rats and hamsters were longer than 5 microns in length. In comparison, fibers longer than 5 microns recovered from the pleural compartment, following a 12-week exposure and 12 weeks of recovery, accounted for 13% (hamsters) and 4% (rats) of the distribution. In the 12 weeks after the cessation of exposure, the number of fibers longer than 5 microns in length remained constant in the hamster at approximately 150 fibers per cm2 pleura. This was 2 to 3 times the corresponding fiber surface density in the rat. Significant pulmonary and pleural inflammation was detected at all time points and for both species. DNA synthesis by pleural mesothelial cells was quantified by bromodeoxyuridine uptake following 3 days of labeling. Labeling indices were higher in hamsters than in rats, both for RCF-1-exposed and filtered air-control animals and was highest for the parietal surface of the pleura. Significantly greater collagen deposition was measured in the visceral pleura of hamsters 12 weeks post-exposure but was not significantly elevated in rats. These findings demonstrate that subchronic inhalation exposure to RCF-1 induces pleural inflammation, mesothelial-cell turnover, pleural fibrosis, and an accumulation of fibers with a length greater than 5 microns in the hamster. The accumulation of long fibers in the pleural space may contribute to the pathology observed in the hamster following chronic inhalation of RCF- 1, whereas the presence of short, thin fibers may play a role in the acute-phase biological response seen in both species.      

伊贝母中伊贝碱甙C的分离和结构鉴定

自吉林栽培的伊贝母(Fritillaria pallidiflora Schrenk)中分得一种新的甾体生物碱甙,命名为伊贝碱甙C(yibeinosideC)。根据红外、质谱、氢谱、碳谱、¹H-¹HCOSY和¹H-¹³CCOSY谱确定其结构为22,26-环亚胺胆甾-6-酮-3-O-β-D-吡喃葡萄糖-(1→4)-β-D-吡喃半乳糖甙(1)。     

A novel protein tyrosine phosphatase gene is mutated in progressive myoclonus epilepsy of the Lafora type (EPM2)

Progressive myoclonus epilepsy of the Lafora type or Lafora disease (EPM2; McKusick no. 254780) is an autosomal recessive disorder characterized by epilepsy, myoclonus, progressive neurological deterioration and glycogen-like intracellular inclusion bodies (Lafora bodies). A gene for EPM2 previously has been mapped to chromosome 6q23- q25 using linkage analysis and homozygosity mapping. Here we report the positional cloning of the 6q EPM2 gene. A microdeletion within the EPM2 critical region, present inhomozygosis in an affected individual, was found to disrupt a novel gene encoding a putative protein tyrosine phosphatase (PTPase). The gene, denoted EPM2, presents alternative splicing in the 5' and 3' end regions. Mutational analysis revealed that EPM2 patients are homozygous for loss-of-function mutations in EPM2. These findings suggest that Lafora disease results from the mutational inactivation of a PTPase activity that may be important in the control of glycogen metabolism.      

Impaired growth in children with asthma during treatment with conventional doses of inhaled corticosteroids

We describe 6 (4F, 2M) prepubertal children with moderate asthma diagnosed at a mean age of 2.8 years. All patients were treated with inhaled corticosteroids in a dose of between 300 and 800 mcg of beclomethasone diproprionate (becotide) daily, given either as an aerosol or rotahaler. Mean height velocity SDS decreased from −0.8(range +0.5 to −2.0)to −3.2(range −1.3 to −4.8) when the dose was increased. Alternatively, when the dose was reduced or stopped, mean height velocity SDS increased from −3.2 (range −2.0 to −4.8) to +0.8 (range −1.2 to +2.7). Careful assessment of height velocity is indicated in all children receiving treatment with inhaled corticosteroids.     

Hypoglycaemia in congenital adrenal hyperplasia

Two young children with salt-losing congenital adrenal hyperplasia developed profound hypoglycaemia. In one child hypoglycaemia occurred after a prolonged fast and in the other it was precipitated by infection. This complication may be more common than the literature suggests, and emergency treatment with glucose or hydrocortisone, given by injection, should be given to any child with the disorder who suddenly or unexpectedly collapses.     

Global approach to hepatic metastases from colorectal cancer: indication and outcome of intra-arterial chemotherapy and other hepatic-directed treatments

Liver metastases of colorectal cancer is present in more than 20% of new diagnosed patients and in 40–60% of relapsed patients. It is a life-threatening prognostic aspect. Hepatic resection, when possible, is the best therapeutic modality, although the overall survival rate is still low (30%). Angiography and intraoperative ultrasonography are useful for resection. The number of hepatic metastases and the surgical margin are probably the most significant prognostic factors. Colorectal cancer may spread predominantly to the liver making regional treatment strategies viable options. Subtotal hepatic resections and segmentectomies are potentially curable procedures for single or small numbers of hepatic metastases without other sites of disease. However, there have been no prospective randomized trials comparing patients with unresected liver metastases and resected metastases. Regional chemotherapy with floxuridine seems usefull combined with hepatic resection or as palliative therapy. Gastric ulcer and biliary sclerosis are the main related toxicities. Patients with localized, unresectable hepatic metastases or concomitant bad medical condition may be candidates for radiation, percutaneous ethanol injection, cryosurgery, percutaneous radiofrequency, hypoxic flow-stop perfusions with bioreductive alkylating agents, hepatic arterial ligation, embolization and chemoembolization. These new hepatic-directed modalities of treatment are being investigated and may offer new approaches to providing palliation and prolonging survival. This review will report the possibilities of intra-arterial chemotherapy and other novel hepatic-directed approaches to the treatment of liver metastases from colorectal cancer.