Venous thromboembolic risk and protein S deficiency: ethnic difference and remaining issues

Protein S deficiency is an autosomal dominant disorder that results from mutations in the protein S gene (PROS1). Inherited deficiency of protein S constitutes a risk factor for venous thromboembolism. Protein S functions as a nonenzymatic cofactor for activated protein C in the proteolytic degradation of coagulation factors V a and Villa. The frequency of protein S deficiency seems to differ between populations. More than 200 rare mutations in PROS1 have been identified in patients with protein S deficiency. Among the prevalent mutations within PROS1, the S460P substitution (known as Heerlen polymorphism) detected in Caucasians and the K196E substitution (known as protein S Tokushima) found in Japanese have been intensively studied for their structures and potential functions in the disorder of protein S deficiency. Until now, causative mutations in PROS1 have been found in only approximately 50% of cases with protein S deficiency. Co-segregation analysis of microsatellite haplotypes with protein S deficiency in families with protein S deficiency suggests that the causative defects in the PROS1 mutation-negative patients are located in or close to the PROS 1 gene. Large PROS 1 gene deletions have been identified in 3 out of 9 PROS 1 mutation-negative Swedish VTE families with protein S deficiency and 1 out of 6 PROS1 mutation-negative Japanese patients with protein S deficiency. Intensive sequencing of the entire PROS 1 gene, including introns, may be needed to identify the cryptic mutations in those patients, and these efforts might uncover the pathogenesis of protein S deficiency.     

Autoimmune pancreatitis associated with a large pancreatic pseudocyst that disappeared after corticosteroid therapy: a case report and literature review

A 51-year-old woman was admitted to our department because of upper abdominal pain. The serum IgG4 concentration was elevated, and abdominal computed tomography revealed diffuse enlargement of the pancreas associated with a large cyst, measuring 8 cm in diameter. Endoscopic retrograde cholangiopancreatography revealed narrowing of the main pancreatic duct (from the body to the tail), narrowing of the intrapancreatic bile duct, and dilatation of the bile ducts. The patient was given a diagnosis of autoimmune pancreatitis (AIP) associated with a pancreatic pseudocyst and intrapancreatic bile duct stenosis. Oral steroid therapy resulted in reduced pancreatic swelling, complete disappearance of the pancreatic cyst, and an improvement in biliary stenosis. AIP is rarely associated with pancreatic cyst, and only 13 cases, including ours, have been reported to date. In our patient, intense inflammation apparently led to cyst formation in association with AIP, which responded remarkably to corticosteroid therapy. Correct diagnosis of AIP associated with a pancreatic pseudocyst might save patients from undergoing unnecessary endoscopic and surgical procedures.     

Rendezvous gastrotomy technique using direct percutaneous endoscopic gastrostomy for transgastric cholecystectomy in hybrid natural orifice translumenal endoscopic surgery

Background/purpose

Transgastric access is a major route in natural orifice translumenal endoscopic surgery (NOTES); gastrotomy should be performed unless it would damage surrounding organs in the peritoneal cavity. This article describes a novel rendezvous gastrotomy technique over a direct percutaneous endoscopic gastrostomy (PEG).

Methods

In six live porcines, the gastrotomy involved applying a direct PEG through the abdominal wall into the stomach and exchanging to a needle trocar. An endoscopic balloon catheter was passed through the trocar by rendezvous technique. Then the inflated balloon and endoscope were advanced to the peritoneal cavity through the gastrotomy. Transgastric cholecystectomy was performed with a hybrid needle grasper through the same percutaneous site and the gastrotomy was closed with endoscopic clips.

Results

The rendezvous gastrotomy technique could reduce guidewire exchange. The success rate was 100% (6/6). Mean times for transgastric peritoneoscopy and cholecystectomy were 25.5 and 83.5 min. Mortality and morbidity was 0%. The addition of the extra trocar was unnecessary in all procedures.

Discussions/conclusions

The advantage of this introduction system includes the creation of controlled gastric perforation, which is easier to close. It provides reliable transgastric access and increases safety. It simplifies transgastric NOTES and provides less invasive hybrid NOTES procedure.     

Pneumocystis jiroveci pneumonia in patients with rheumatoid arthritis treated with infliximab: A retrospective review and case–control study of 21 patients

Objective

To establish proper management of Pneumocystis jiroveci pneumonia (PCP) in rheumatoid arthritis (RA) patients treated with infliximab. PCP has been observed in 0.4% of patients with RA treated with infliximab in Japan.

Methods

Data from patients with RA (n = 21) who were diagnosed with PCP during infliximab treatment and from 102 patients with RA who did not develop PCP during infliximab therapy were collected from 14 rheumatology referral centers in Japan. A retrospective review of these patients and a case–control study to compare patients with and without PCP were performed.

Results

The median length of time from the first infliximab infusion to the development of PCP was 8.5 weeks. At the onset of PCP, the median dosages of prednisolone and methotrexate were 7.5 mg/day and 8 mg/week, respectively. Pneumocystis jiroveci was microscopically identified in only 2 patients, although the polymerase chain reaction test for the organism was positive in 20 patients. The patients with PCP had significantly lower serum albumin levels (P < 0.001) and lower serum IgG levels (P < 0.001) than the patients without PCP. Computed tomography of the chest in all patients with PCP revealed ground‐glass opacity either with sharp demarcation by interlobular septa or without interlobular septal boundaries. Sixteen of the 21 patients with PCP developed acute respiratory failure, but all survived.

Conclusion

PCP is a serious complication that may occur early in the course of infliximab therapy in patients with RA. For the proper clinical management of this infectious disease, physicians need to be aware of the possibility of PCP developing during infliximab therapy.     

Screening of chondrogenic factors with a real‐time fluorescence‐monitoring cell line ATDC5‐C2ER: Identification of sorting nexin 19 as a novel factor

Objective

To establish a cell culture system for noninvasive and real‐time monitoring of chondrogenic differentiation in order to screen for chondrogenic factors.

Methods

The optimum reporter construct transfected into chondrogenic ATDC5 cells was selected by a luciferase reporter assay and fluorescence analysis during cultures with insulin. The established cell line was validated according to its fluorescence following stimulation with SOX proteins, bone morphogenetic protein 2 (BMP‐2), or transforming growth factor β (TGFβ) and was compared with the level of messenger RNA for COL2A1 as well as with the degree of Alcian blue staining. Screening of chondrogenic factors was performed by expression cloning using a retroviral expression library prepared from human tracheal cartilage. The expression pattern of the identified molecule was examined by in situ hybridization and immunohistochemistry. Functional analysis was performed by transfection of the identified gene, the small interfering RNA, and the mutated gene.

Results

We established an ATDC5 cell line with 4 repeats of a highly conserved enhancer ligated to a COL2A1 basal promoter and the DsRed2 reporter (ATDC5‐C2ER). Fluorescence was induced under the stimulations with SOX proteins, BMP‐2, or TGFβ, showing good correspondence to the chondrogenic markers. Screening using the ATDC5‐C2ER system identified several chondrogenic factors, including sorting nexin 19 (SNX19). SNX19 was expressed in the limb cartilage of mouse embryos and in the degraded cartilage of adult mouse knee joints during osteoarthritis progression. The gain‐of‐function and loss‐of‐function analyses revealed a potent chondrogenic activity of SNX19.

Conclusion

We established the ATDC5‐C2ER system for efficient monitoring of chondrogenic differentiation by fluorescence analysis, and we identified a novel chondrogenic factor (SNX19) using this system. This system will be useful for elucidating the molecular network of chondrogenic differentiation.

     

Epstein–Barr virus-positive diffuse large B-cell lymphoma carrying a t(9;14)(p13;q32) translocation

We, herein, report a 75-year-old man with lymphoma who initially presented with disseminated disease involving the lung, followed by temporal regression, and finally died of disease progression. Lymph-node biopsy showed a morphology of diffuse large B-cell lymphoma (DLBCL), containing CD30⁺ Reed–Sternberg-like cells. The lymphoma cells were stained by in situ hybridization (ISH) for Epstein–Barr virus (EBV)-encoded RNA, and the presence of the EBV genome was confirmed by the polymerase chain reaction. A cytogenetic study showed that the lymphoma cells carried a t(9;14)(p13;q32) translocation, and rearrangement of the PAX5 gene was determined by fluorescence ISH using a split signal probe. This case report is the first to identify t(9;14)(p13;q32) in EBV⁺ DLBCL of the elderly, which was very recently listed among subtypes of DLBCL.     

Blood–brain barrier transport of naloxone does not involve P-glycoprotein-mediated efflux

The blood–brain barrier (BBB) transport of naloxone, a potent and specific opioid antagonist, was investigated in rats using the brain uptake index method and the brain efflux index method. The apparent influx clearance of [³H]naloxone across the BBB was 0.305 mL/min/g brain. [³H]naloxone was eliminated from the brain with an apparent elimination half-life of 15.1 min after microinjection into the parietal cortex area 2 regions of the rat brain. The apparent efflux clearance of [³H]naloxone across the BBB was 0.152 mL/min/g brain, which was calculated from the elimination rate constant (4.79 × 10^?2 min^?1) and the distribution volume in the brain (3.18 mL/g brain). The influx clearance across the BBB was two times greater than the efflux clearance. The elimination of [³H]naloxone from the brain was not inhibited in the presence of the typical P-glycoprotein (P-gp) inhibitors such as quinidine, verapamil, vinblastine, and vincristine, indicating that naloxone is not a P-gp substrate in the rat. In vitro experiments by using human multidrug resistance 1 (MDR1)/P-gp overexpressing HeLa cells showed that the uptake of naloxone by the cells did not change in the presence of the P-gp inhibitors. In conclusion, the present results obtained from in vivo and in vitro studies suggest that P-gp is not involved in the BBB transport of naloxone. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:413–421, 2010     

Small GTPase Rnd1 is involved in neuronal activity-dependent dendritic development in hippocampal neurons

Rho family small GTPases are key regulators for neuronal morphogenesis including dendritogenesis. We recently have shown that Rnd1, a member of the Rho family, is highly expressed in brain during the synaptogenic stage and is involved in dendritic spine formation. However, the mechanism by which Rnd1 regulates dendritic development including spine morphogenesis remains unknown. Here we report that Rnd1, a member of the Rho family, plays a critical role in neuronal activity-dependent dendritic development in hippocampal neurons. Overexpression of Rnd1 promoted dendritic growth and branching in cultured hippocampal neurons. On the other hand, suppression of endogenous Rnd1 expression by RNA interference significantly inhibited neuronal activity-dependent dendritic development and this inhibitory effect was canceled by inhibition of RhoA effector ROCK. In addition, knockdown of Rnd1 also abolished dendritic development promoted by treatment with brain-derived neurotrophic factor in hippocampal neurons. Our findings demonstrate that Rnd1 is involved in signaling pathways of neuronal activity-dependent dendritic development.     

Formation of acellular cementum-like layers, with and without extrinsic fiber insertion, along inert bone surfaces of aging c-Src gene knockout mice

To investigate the long-term effects of c-src deficiency on skeletal and dental tissues, we examined the lower jaws and long bones of c-src gene knockout (c-src KO) mice by histological and histochemical methods. Numerous multinucleated osteoclasts were distributed throughout the mandible in 5-wk-old c-src KO mice, but by 14 wk they had almost completely disappeared from the alveolar bone, leaving tartrate-resistant acid phosphatase (TRAP)-positive layers along the bone surface. Deposition of osteopontin-positive mineralized tissue, reminiscent of acellular afibrillar cementum (AAC), was confirmed along the TRAP-positive bone surface at 14 wk. The layer progressively thickened up to 21 months. A comparable mineralized layer was noted along the trabeculae of long bones as thickened cement lines. In the periostin-rich areas of jaw bones, but not in the long bones, portions of AAC-like mineralized layers were often replaced with and/or covered by acellular extrinsic fiber cementum (AEFC)-like tissue. These data suggest that the deposition of AAC-like mineralized tissue is a general phenomenon that may occur along inert or slowly remodeling bone surfaces under conditions characterized by reduced bone-resorbing activity, whereas the induction of AEFC-like tissue seems to be associated with the expression of certain molecules that are particularly abundant in the microenvironment of the periodontal ligament.