Fiberoptic bronchoscopy induces platelet activation

The plasma membrane Ca²⁺-ATPase (PMCA) plays an essential role in maintaining low cytosolic Ca²⁺ in resting human platelets by extruding Ca²⁺ from the cytoplasm across the plasma membrane. Since PMCA is the main agent of Ca²⁺ efflux in platelets, it is a key point for regulation of platelet Ca²⁺ metabolism. PMCA has been shown to be an excellent substrate for the Ca²⁺-activated cysteine protease calpain, a major platelet protein that is turned on during platelet activation. The objectives of the present work were to determine if PMCA is degraded during thrombin- and collagen-mediated platelet activation, and if calpain is responsible. The kinetics of PMCA degradation during platelet activation were analysed using SDS polyacrylamide gel electrophoresis and immunoblotting. The role of calpain was tested using the calpain inhibitors calpeptin and ALLN. Platelet activation mediated by both collagen and thrombin resulted in degradation of 60% of platelet PMCA within 18 minutes. Calpeptin and ALLN significantly inhibited the rate and extent of PMCA degradation. We conclude that calpain-mediated degradation of PMCA during platelet activation likely contributes significantly to Ca²⁺ regulation and, therefore, to platelet function.     

Total pancreas divisum caused by ventral pancreas malrotation showing biliary pancreatitis

A 52-year-old man was admitted to our hospital complaining of abdominal pain. A blood test showed high serum levels of biliary enzymes and amylase. Surprisingly, a computed tomography scan revealed complete separation of the ventral and dorsal pancreas and swelling of the ventral pancreas with choledocholithiasis. Surgical cholecystectomy was performed to remove the bile duct stones after endoscopic removal was unsuccessful. The complete separation of the pancreatic parenchyma caused by ventral pancreas malrotation seen in this case is extremely rare, and may provide important information regarding embryologic development, deformity, and malfunction of the pancreas.     

Desmoplastic response in biopsy specimens of early colorectal carcinoma is predictive of deep submucosal invasion

PURPOSE: The aim of this study was to evaluate the role of histopathology of biopsy specimens in predicting depth of infiltration in early colorectal carcinomas before treatment. METHODS: Early colorectal carcinomas that had been resected surgically or endoscopically between 1984 and 1995 were analyzed. Histopathologic findings, including differentiation of adenocarcinoma and a desmoplastic response were investigated. RESULTS: One hundred nine early colorectal carcinomas consisted of 73 lesions of carcinomain situ, 13 submucosal carcinomas with minimum invasion, 8 lesions with moderate invasion, and 15 lesions with deep invasion. Of 73 carcinomain situ lesions, 72 (approximately 99 percent) showed well-differentiated adenocarcinomas and no desmoplastic response. Twelve (92 percent) of 13 submucosal carcinomas with minimum invasion also revealed well-differentiated adenocarcinoma without a desmoplastic response. Sixty-three percent (5/8)of lesions with moderate invasion revealed well-differentiated adenocarcinoma. None of the lesions had a desmoplastic response. Among lesions with deep invasion, 73 percent (11/15) demonstrated moderately differentiated adenocarcinoma, and 11 lesions had a prominent desmoplastic response (73 percent;P<0.01). CONCLUSIONS: These results suggest that if histopathologic findings of biopsy specimens taken from them before treatment demonstrated adenocarcinoma associated with a desmoplastic response, the lesions had at least deep invasion carcinomas. These lesions should be resected surgically. Submucosal carcinomas with minimum invasion, which have no desmoplastic response, could be treated endoscopically.     

Interstitial deletion of the proximal long arm of chromosome 4 associated with father-child incompatibility within the Gc- system: Probable reduced gene dosage effect and partial piebald trait

Gc-system typing by isoelectric focusing polyacrylamide gel electrophoresis and quantitative assays were carried out on a patient with a karyotype of 46,XY,del(4)(q12q21.1) and on his parents with normal chromosomes. Although a father-child incompatibility within the Gc-system suggested that its locus is on segment 4q12-13, the serum concentration of vitamin D binding protein in the patient and his father were only about half of that of his mother and control individuals. The possibility of interference of a silent allele in the child could not be excluded. Associated congenital partial leukodermia appeared to be an expression of a partial piebald trait.     

B cells expressing CD5 antigen are markedly increased in peripheral blood and spleen lymphocytes from patients with immune thrombocytopenic purpura

By two-colour flow cytometric analysis, we examined the proportion of B lymphocytes bearing CD5 cell surface antigen (CD 5+ B cells), which are capable of producing autoantibodies, both in peripheral blood and spleen from patients with chronic immune thrombocytopenic purpura (ITP). The percentage of CD5+ B cells in peripheral blood lymphocytes (PBLs) was significantly increased (P less than 0.005) in patients with ITP (3.7 +/- 2.2%, n = 30) as compared with normal controls (1.7 +/- 0.7%, n = 28). However, there was no correlation between the percentages of circulating CD5+ B cells and platelet counts. The percentage of splenic CD5+ B cells in ITP patients was much more increased (9.0 +/- 4.5%, n = 9), P less than 0.005) compared with that of other disorders (3.2 +/- 0.5%, n = 5). Furthermore, isolated splenic CD5+ B cells from two out of five ITP patients produced high levels of IgM-type, platelet-bindable antibodies (PBIgM) after stimulation with Staphylococcus aureus Cowan I (SAC), while CD5- B cells isolated from the same spleen or splenic CD5+ B cells from other non-autoimmune disorders failed to produce significant amount of PBIgM. In three ITP patients, no increase in PBIgM was detected despite SAC stimulation. The increased proportion of CD5+ B cells in peripheral blood and spleen, and their ability to produce anti-platelet antibodies indicate that they are directly involved in the autoimmune pathogenesis in ITP.     

Reduced hemoglobin and increased C-reactive protein are associated with upper gastrointestinal bleeding

AIM: To investigate the early upper gastrointestinal endoscopy(endoscopy) significantly reduces mortality resulting from upper gastrointestinal(GI) bleeding. METHODS: Upper GI bleeding was defined as 1a, 1b, 2a, and 2b according to the Forrest classification. The hemoglobin(Hb), and C-reactive protein(CRP) were examined at around the day of endoscopy and 3 mo prior to endoscopy. The rate of change was calculated as follows:(the result of blood examination on the day of endoscopy- the results of blood examination 3 mo prior to endoscopy)/(results of blood examination 3 mo prior to endoscopy). Receiver operating characteristic curves were created to determine threshold values. RESULTS: Seventy-nine men and 77 women were enrolled. There were 17 patients with upper GI bleeding: 12 with a gastric ulcer, 3 with a duodenal ulcer, 1 with an acute gastric mucosal lesion, and 1 with gastric cancer. The area under the curve(AUC), threshold, sensitivity, and specificity of Hb around the day of endoscopy were 0.902, 11.7 g/dL, 94.1%, and 77.1%, respectively, while those of CRP were 0.722, 0.5 mg/dL, 70.5%, and 73%, respectively. The AUC, threshold, sensitivity, and specificity of the rate of change of Hb were 0.851,-21.3%, 76.4%, and 82.6%, respectively, while those of CRP were 0.901, 100%, 100%, and 82.5%, respectively. CONCLUSION: Predictors for upper GI bleeding were Hb < 11.7 g/dL, reduction rate in the Hb > 21.3% and an increase in the CRP > 100%, 3 mo before endoscopy.     

Prognostic value of KRAS and BRAF mutations in curatively resected colorectal cancer

AIM: To investigate the prognostic role of KRAS and BRAF mutations after adjustment for microsatellite instability(MSI) status in Japanese colorectal cancer(CRC) population.METHODS: We assessed KRAS and BRAF mutations and MSI status in 813 Japanese patients with curatively resected, stage Ⅰ-Ⅲ CRC and examined associations of these mutations with disease-free survival(DFS) and overall survival(OS) using uni- and multivariate Cox proportional hazards models.RESULTS: KRAS and BRAF mutations were detected in 312(38%) of 812 and 40(5%) of 811 tumors, respectively. KRAS mutations occurred more frequently in females than in males(P = 0.02), while the presence of BRAF mutations was significantly associated with the female gender(P = 0.006), proximal tumor location(P 0.001), mucinous or poorly differentiated histology(P 0.001), and MSI-high tumors(P 0.001). After adjusting for relevant variables, including MSI status, KRAS mutations were associated with poorer DFS(HR = 1.35; 95%CI: 1.03-1.75) and OS(HR = 1.46; 95%CI: 1.09-1.97). BRAF mutations were poor prognostic factors for DFS(HR = 2.20; 95%CI: 1.19-4.06) and OS(HR = 2.30; 95%CI: 1.15-4.71). Neither the BRAF by MSI interaction test nor the KRAS by MSI interaction test yielded statistically significant results for DFS and OS.CONCLUSION: KRAS and BRAF mutations are associated with inferior survival, independent of MSI status, inJapanese patients with curatively resected CRC.     

Genotype Frequencies of the Human Platelet Antigen,Ca/Tu,in Japanese,Determined by a PCR-RFLP Method

Recently, the polymorphism of a new human platelet antigen, Ca/Tu, was shown to be derived from a G-A nucleotide substitution at base 1564 of GPIIIa cDNA, which leads to a single amino acid difference, Arg/Gln at amino acid 489 of GPIIIa. We developed a PCR-RFLP method to determine the genotypes of Ca/Tu and their frequencies in a Japanese population. Fifteen Ca/Tu^a donors comprising 1 Ca/Tu(a/a) homozygous donor and 14 Ca/Tu(a/b) heterozygous donors were found among the 314 random donors analyzed. The frequencies of Ca/Tu genes were 0.025 (Ca/Tu^a) and 0.975 (Ca/Tu^b). The present study showed that the frequency of Ca/Tu^a individuals in the Japanese (15/314) was approximately 7-fold higher than in the Finnish population (1/150) previously reported by Kekomäki et al. Therefore, attention must be given to the involvement of the Ca/Tu alloantigen in neonatal alloimmune thrombocytopenia and the refractoriness of platelet transfusion.