Splenic lymphoma with villous lymphocytes involves B cells with extensively mutated Ig heavy chain variable region genes

Splenic lymphoma with villous lymphocytes (SLVL) is a recently defined subgroup of chronic B-cell lymphoproliferative diseases. The characteristic morphology of the tumor cells, together with phenotypic and cytogenetic findings, indicate that it is a distinct entity, but the nature of the cell or origin and its relationship to other low- grade lymphomas is unclear. For B-cell tumors, analysis of the variable region heavy chain (VH) genes used to encode the clonal Ig has shown marked differences between histologic categories, both in gene usage and extent of somatic mutation. An investigation of VH genes used in five typical cases of SLVL has shown somatic hypermutation from germline sequences in all cases, indicating that the cell of origin has been exposed to the hypermutation mechanism. However, no clonal heterogeneity was detectable, demonstrating that the tumor cell does not accumulate further mutations. These characteristics are similar to those found in mature postfollicular B cells, such as plasma cells. The distribution of mutations leading to replacement amino acids differed among the cases, with three of five cases showing clear evidence for antigen selection.     

Management of Hepatitis B Virus Infection in Liver Transplantation Setting; The Rising Concerns and Growing Hopes,Report From 10th Congress of the Iranian Society for Organ Transplantation, 2011, Shiraz,Iran

Hepatitis B infection is the main cause of liver related mortality in many countries including Iran. Liver transplantation in cirrhosis due to HBV infection before 1990 was an absolute contraindication. Recurrent infection was a significant event in post liver transplant setting and resulted in increased risk of graft failure and death except successful transplanted individuals. Advances in antiviral prophylaxis have now made graft reinfection majority patients as a rare event. Graft and patient survival have been improved significantly during the past two decades, and consequences of transplantation for hepatitis B virus are now superior to those achieved for most other indications. This has encouraged many centers including the major liver transplantation center of Iran, in Shiraz, to provide liver transplantation to more patients with HBV related end stage liver disease. Management of these patients begins before transplantation along with special care after transplantation. There are some myths and doubts in the management of these patients and one should always balance the cost and efficiency. One of the major concerns is the high economic and social cost of recurrence and all possible efforts should be performed to avoid the ominous consequences of reinfection. Having a clear scientific grasp on the management of HBV cirrhosis before and after liver transplantation, options and protocols, and changing the concept which HBV infected are contraindicated ones for liver transplantation, and future hopes in increasing patients survival after liver transplantation using the new nucleosides analogues and availability of hepatitis B immunoglobulin in the transplantation setting. This scientific report paper outlines the insights communicated at the HBV and liver transplantation symposium during 10th Congress of the Iranian Society for Organ Transplantation, May 2011, Shiraz, Iran.     

Long-term effects of nitrous oxide anaesthesia on laboratory and clinical parameters in elderly Omani patients: a randomized double-blind study

AIMS: This study examined the long-term effects of nitrous oxide anaesthesia on serum levels of cobalamin and folate, red cell folate levels and haematological parameters, and neurological status in elderly Omani patients. METHODS: Sixty-nine consecutive patients undergoing ophthalmic surgery were randomly and double-blind assigned to nitrous oxide or propofol anaesthesia. They met the following entry criteria: age 55 years or above, no major organ failure, no clinical signs or symptoms of cobalamin or folate deficiency, mean cell volume (MCV) 相似文献   

Construction of an MR/P fimbrial mutant of Proteus mirabilis: role in virulence in a mouse model of ascending urinary tract infection.

Proteus mirabilis, a cause of acute pyelonephritis, produces at least four types of fimbriae, including MR/P (mannose-resistant/Proteus-like) fimbriae. To investigate the contribution of MR/P fimbriae to colonization of the urinary tract, we constructed an MR/P fimbrial mutant by allelic exchange. A 4.2-kb BamHI fragment carrying the mrpA gene was subcloned into a mobilizable plasmid, pSUP202. A 1.3-kb Kanr cassette was inserted into the mrpA open reading frame, and the construct was transferred to the parent P. mirabilis strain by conjugation. Following passage on nonselective medium, 1 of 500 transconjugants screened was found to have undergone allelic exchange as demonstrated by Southern blot. Colony immunoblot, Western immunoblot, and immunogold labeling with a monoclonal antibody to MR/P fimbriae revealed that MrpA was not expressed. Complementation with cloned mrpA restored MR/P expression as shown by hemagglutination, Western blot, and immunogold electron microscopy. To assess virulence, we challenged 40 CBA mice transurethrally with 10(7) CFU of wild-type or mutant strains. After 1 week, geometric means of log10 CFU per milliliter of urine or per gram of bladder or kidney for the wild-type and mutant strains were as follows: urine, 7.79 (wild type) versus 7.02 (mutant) (P = 0.035); bladder, 6.22 versus 4.78 (P = 0.019); left kidney, 5.02 versus 3.31 (P = 0.009); and right kidney, 5.28 versus 4.46 (P = 0.039). Mice challenged with the wild-type strain showed significantly more severe renal damage than did mice challenged with the MR/P-negative mutant (P = 0.007). We conclude that MR/P fimbriae contribute significantly to colonization of the urinary tract and increase the risk of development of acute pyelonephritis.     

Medical service provider networks

In many countries, health insurers or health plans choose to contract either with any willing providers or with preferred providers. We compare these mechanisms when two medical services are imperfect substitutes in demand and are supplied by two different firms. In both cases, the reimbursement is higher when patients select the in‐network provider(s). We show that these mechanisms yield lower prices, lower providers' and insurer's profits, and lower expense than in the uniform‐reimbursement case. Whatever the degree of product differentiation, a not‐for‐profit insurer should prefer selective contracting and select a reimbursement such that the out‐of‐pocket expense is null. Although all providers join the network under any‐willing‐provider contracting in the absence of third‐party payment, an asymmetric equilibrium may exist when this billing arrangement is implemented.