Y chromosome haplogroup N in a Japanese population is classified into three subclades, and two DYS385 loci, a duplicated Y-STR, are duplicated again in subclade N-M1819

DYS385 is one of the major Y chromosome short tandem repeats (Y-STRs) in forensic genetics and exists as 2 copies in the human Y chromosome palindrome P4 region. In this study, we found that some samples were estimated to have ≥ 4 copies of DYS385 in Y chromosome haplogroup N in a Japanese population. Y chromosome haplogroup N is distributed widely in eastern/central Asia, Siberia, and eastern/northern Europe, and is also observed in Japan; however, little is known about haplogroup N subclades in the Japanese population. To reveal the link between increased DYS385 copy number and haplogroup N subclades, we sequenced single nucleotide polymorphisms to classify the subclades. As a result, the Japanese Y chromosomes of haplogroup N were classified into three subclades, and an increased DYS385 copy number was specific to subclade N-M1819* (N1b2*). These results are of use in forensic DNA analysis because Y-STR copy number is important for the interpretation of Y-STR typing results of male DNA mixtures and kinship analysis. We also found that DYS458.1 microvariants (DYS458 intermediate alleles with single-nucleotide insertion) were observed only in subclade N-CTS962 (N1b1b∼) samples. Given that previous studies reported that DYS458.1 microvariants are observed in Y chromosomes of haplogroup N in other populations, DYS458.1 might be used to infer haplogroup N subclades without limitation to the Japanese population. The results of this study will be beneficial not only to forensic genetics but also to anthropological studies.

Frequencies of D19S433 silent alleles in a Japanese population of 1501 individuals and their effect on likelihood ratios calculated in kinship tests

Although silent alleles in D19S433 typing using the GlobalFiler PCR Amplification Kit have been reported, the exact frequency of the D19S433 silent alleles in population data of 1501 Japanese individuals, which are widely used for the assessment of Japanese STR typing results, is unclear. In this study, we examined the exact D19S433 silent allele frequency in this population data. We newly observed the G32A variant causing silent alleles at D19S433 in five samples. Combining them with data including 30 samples with the variant reported previously, we determined that the total frequency of the silent alleles (i.e. the frequency of the G32A variant) in the 1501 Japanese samples was 0.0117 (35/3002). Using the D19S433 allele frequency data, we evaluated the effect of presence/absence information for the D19S433 silent allele on kinship tests. Likelihood ratios (LRs) were calculated for both simulated parent-child and full sibling cases, revealing that the LR may change by approximately 10^-2 to 10³ fold when the presence/absence of the D19S433 silent allele is revealed in a kinship test. Therefore, if a sufficiently large or small LR is obtained, there is little need to determine the presence/absence of the D19S433 silent allele in Japanese kinship tests using GlobalFiler. This study will be beneficial for the assessment of Japanese human identification and kinship test results using GlobalFiler.

Ratios and distances of pull-up peaks observed in GlobalFiler kit data

Short tandem repeat (STR) analysis is widely used for forensic examinations with a capillary electrophoresis instrument such as the 3500xL Genetic Analyzer. This instrument adapts multi-locus STR kits to examine up to 27 loci using a 6-fluorescent dye system and corrects the spectral overlap between each dye. However, inaccurate spectral correction can cause pull-up peaks. Here, we examined the pull-up peaks observed in GlobalFiler kit data in terms of their peak height ratios and distances from their parent allele peaks when using the 3500xL and the 3130xl Genetic Analyzers. With the 3500xL, 546 pull-up peaks were observed, and their pull-up ratios averaged 1.03 ± 0.32% (range 0.260-2.80%). Of the 546 pull-up peaks, 534 peaks (97.8%) were within ±1 bp from their parent allele peaks. Overall, the pull-up peaks toward adjacent shorter wavelength channels (e.g., from yellow to green) tended to be observed in the left side (shorter bp) of the corresponding parent allele peaks, and the opposite side tendency was observed for those pull-up peaks toward adjacent longer wavelength channels. These tendencies were also observed in the GlobalFiler data generated with the 3130xl and in the data obtained by injecting a J6 matrix standard with LIZ 500 or 600 v2 size standard into the 3500xL and 3130xl. Inspection of raw data revealed that the shift of pull-up peaks from their parent allele peaks was derived from sigmoid, pull-down, or slightly shifted pull-up shapes. Based on the obtained data, we propose a standard for assessment of questionable pull-up peaks.

Next-generation sequencing analysis of off-ladder alleles due to migration shift caused by sequence variation at D12S391 locus

In short tandem repeat (STR) analysis, length polymorphisms are detected by capillary electrophoresis (CE). At most STR loci, mobility shift due to sequence variation in the repeat region was thought not to affect the typing results. In our recent population studies of 1501 Japanese individuals, off-ladder calls were observed at the D12S391 locus using PowerPlex Fusion in nine samples for allele 22, one sample for allele 25, and one sample for allele 26. However, these samples were typed as ordinary alleles within the bins using GlobalFiler. In this study, next-generation sequencing analysis using MiSeq was performed for the D12S391 locus from the 11 off-ladder samples and 33 other samples, as well as the allelic ladders of PowerPlex Fusion and GlobalFiler. All off-ladder allele 22 in the nine samples had [AGAT]11[AGAC]11 as a repeat structure, while the corresponding allele was [AGAT]15[AGAC]6[AGAT] for the PowerPlex Fusion ladder, and [AGAT]13[AGAC]9 for the GlobalFiler ladder. Overall, as the number of [AGAT] in the repeat structure decreased at the D12S391 locus, the peak migrated more slowly using PowerPlex Fusion, the reverse strand of which was labeled, and it migrated more rapidly using GlobalFiler, the forward strand of which was labeled. The allelic ladders of both STR kits were reamplified with our small amplicon D12S391 primers and their mobility was also examined. In conclusion, off-ladder observations of allele 22 at the D12S391 locus using PowerPlex Fusion were mainly attributed to a relatively large difference of the repeat structure between its allelic ladder and off-ladder allele 22.

D5S818 Typing Discrepancy Between PowerPlex(®) Fusion and Other STR Kits Including GlobalFiler(®) Caused by a One-base Deletion in 31 Nucleotides Upstream of the Repeat Region

Short tandem repeat (STR) typing is widely used in forensic investigation. When the same DNA sample is analyzed with different STR typing kits, a typing discrepancy is occasionally observed. In this study, we examined the cause of a typing discrepancy in a sample at D5S818 locus. This sample was designated as 10, 12 using Identifiler(®) , Identifiler(®) Plus, GlobalFiler(®) , PowerPlex(®) 16HS, and PowerPlex(®) 18D, but as 9.3, 12 using PowerPlex(®) Fusion. Sequencing results indicated that the shorter allele in the sample had a deletion (U31Tdel) at 31 nucleotides upstream of the repeat region (AGAT)10 . This deletion was located in the binding site of the published D5S818 forward primer in PowerPlex(®) 16 and was only 9 and 11 nucleotides downstream of our estimated 5' end position of D5S818 forward primer in GlobalFiler(®) and PowerPlex(®) 18D, respectively. We also examined the effect of primer length on the heterozygous peak balance in this sample.

CTF1-51, a truncated carboxyl-terminal fragment of amyloid precursor protein, suppresses the effects of Aβ42-lowering γ-secretase modulators

The pathogenesis of Alzheimer's disease (AD) is correlated with the toxicity of amyloid β-peptide (Aβ), especially Aβ42. γ-Secretase modulators (GSMs) are compounds that alter production of Aβ42 without interfering with the physiological function of γ-secretase. Aβ42-lowering GSMs have been studied with the hope of using them as therapeutic or prophylactic drugs for AD. However, the mechanism of action of GSMs is not well defined. We examined the effect of Aβ42-lowering GSMs on model cells producing large amounts of Aβ42: CHO cells expressing CTF1-51, a precursor peptide of Aβ that is mainly cleaved into Aβ42. Our results indicate that the effect of GSM in the model was weak. Thus, we conclude that CTF1-51 cleavage mainly yields Aβ42 and suppresses the effects of some GSMs, a phenomenon that may be related to their mechanism of action.

Evaluation of the pancreas: a comparison of single thick-slice MR cholangiopancreatography with multiple thin-slice volume reconstruction MR cholangiopancreatography

OBJECTIVE

The purpose of this study was to assess abilities of single thick-slice MR cholangiopancreatography and multiple thin-slice multiprojection volume reconstruction (MPVR) MR cholangiopancreatography to evaluate diseases in and around the pancreas.

SUBJECTS AND METHODS

Eighty-nine patients underwent both single and MPVR MR cholangiopancreatography using a single-shot fast spin-echo technique. Image quality (five-point scale), visualization of the common bile and pancreatic ducts (three-point scale), stenotic, dilatational, or cystic changes of the pancreatic ducts, and other pathologic findings were evaluated.

RESULTS

Image quality was high for single and MPVR MR cholangiopancreatography (4.1+/-0.7 and 4.5+/-0.6, respectively). Misregistration was noted in 19 patients with MPVR MR cholangiopancreatography. Ducts on and around the greater duodenal papilla and the common bile duct were revealed better using MPVR than single MR cholangiopancreatography (p < .05). Overall sensitivity, specificity, and accuracy for detection of stenosis of the main pancreatic ducts were 83.3%, 93.6%, and 88.8%, respectively, using single MR cholangiopancreatography and 76.2%, 97.9%, 87.6%, respectively, using MPVR MR cholangiopancreatography. Dilatation of the pancreatic ducts (100%) and cystic changes (n = 17 and n = 19, respectively) were well seen using either single or MPVR MR cholangiopancreatography. Although stenotic changes of the nondilated main pancreatic ducts and their branches were difficult to evaluate using single (62.5% and 14.3%, respectively) or MPVR (43.8% and 21.4%, respectively) MR cholangiopancreatography, single MR cholangiopancreatography better depicted ductal continuity.

CONCLUSION

For evaluation of the pancreas, single and MPVR MR cholangiopancreatography provide complementary data; thus, we recommend using a combination of these two MR cholangiopancreatography techniques.

Evaluation of endoscopic ultrasonography as an indicator for surgical treatment of gastric cancer

BACKGROUND AND METHODS

Clinicopathological analysis of 346 patients with gastric cancer was made retrospectively and new criteria for the indication of a limited operation using endoscopic ultrasonography (EUS) was developed. Suggested new criteria for selecting gastric cancer patients for the limited operation were: (i) the cancer is located in the mucosa and the lymph nodes are not involved as indicated by EUS examination; (ii) the maximum size of the tumour is less than 2.0 cm; (iii) there are no multiple gastric cancers or simultaneous abdominal cancers; and (iv) the mucosal cancer of elevated type less than 2.0 cm is excluded because there are good indications for endoscopic mucosal resection.

RESULTS AND CONCLUSIONS

We applied these new criteria to 262 patients and found that the patients who had limited operation had the same prognosis and a better quality of life compared with patients who had the conventional operation.

[Clinical efficacy of MRCP for diagnosis of patients with pancreatic neoplasm]

We examined the usefulness of MRCP in pancreatic cancer compared with ERCP. Moreover, it examined in the same way in focal pancreatitis, too. We compare three findings of 1) main pancreatic duct, 2) branches of the stricture part, 3) side of tail main pancreatic duct about ERCP and MRCP. As for the branches of the stricture part, MRCP was poor compared with ERCP but as for the property of the side of the tail main pancreatic duct, MRCP excelled. The study of mass forming chronic pancreatitis was a similar result and was not the one, which excels ERCP in case of qualitative diagnosis. However, we thought that it was not invasively, suitable behind the digestive operation and digestive passage fault, in case of elapse observation and moreover that MRCP is suitable for pick up the pancreatic cancer in our clinic.

MR and CT cholangiography in evaluation of the biliary tract

OBJECTIVE

To compare MR and CT cholangiography (MRC and CTC) in evaluating the anatomy of the extrahepatic biliary tract and the pathology related to the gallbladder.

MATERIAL AND METHODS

Twenty-three patients underwent MRC and CTC with a biliary contrast medium for investigation of biliary disease. 3D displays of both were also obtained. Endoscopic retrograde cholangiography was performed in 17 patients, and the pathology of all 23 was evaluated.

RESULTS

Overall, the image quality was higher with CTC than with MRC (4.7 vs 3.9, p < 0.05). The cystic duct was demonstrated better by CTC than MRC (p < 0.05). Multiplanar reformation (MPR) and source images provided additional information to that obtained from 3D MRC and CTC images. Gallstones were revealed in 6 patients by CTC and in 5 of these 6 by MRC. In 2 patients with cholecystitis, CTC demonstrated gallbladder wall thickening but MRC did not. In 3 patients with adenomyomatosis. MRC demonstrated Rokitansky-Aschoff sinuses (RAS) while CTC demonstrated focal gallbladder wall thickening in all 3 and RAS in 1 of them.

CONCLUSION

Both MRC and CTC provided anatomical and pathological information about the biliary system. With both techniques, however, either MPR or source images proved necessary in addition for evaluating the biliary system anatomy and pathology. The gallbladder wall was depicted clearly in source CTC, but MRC is recommended for the evaluation of adenomyomatosis because it depicts RAS clearly.

Nonfunctional paraganglioma of the pancreas: report of a case

We report herein the case of a 61-year-old man found to have a rare nonfunctional paraganglioma of the pancreas. Interestingly, the preoperative data and images showed similar characteristics to neuroendocrine tumors of the pancreas. Both paragangliomas and neuroendocrine tumors of the pancreas belong to the category of Amine Precursor Uptake and Decarboxylation (APUD) tumors (APUDomas). Thus, it is important to examine the serum level of pancreatic endocrine hormones and a variety of peptides to differentiate paragangliomas of the pancreas from other pancreatic tumors. Paragangliomas of the pancreas grow slowly, so radical resection is recommended to achieve curability with a good prognosis.

A rare case of serous cystadenoma of the pancreas presenting with left-sided portal hypertension

We herein report the case of a 63-year-old woman with a serous cystadenoma of the pancreas presenting with left-sided portal hypertension secondary to isolated splenic vein occlusion. She was admitted to our hospital for sudden hematemesis. Emergency upper gastrointestinal endoscopy revealed hemorrhagic erosive gastritis and isolated varices in the gastric fundus. An abdominal angiographic study disclosed a large hypervascular tumor of the pancreatic tail which caused isolated splenic vein occlusion by tumor compression and formed large hepatopetal collaterals via the gastric varices. The patient underwent tumor resection with splenectomy and, as a result, the gastric varices disappeared and the postoperative course was uneventful. Left-sided portal hypertension secondary to splenic vein occlusion is an uncommon complication mostly associated with pancreatitis and pancreatic carcinoma. Although benign pancreatic neoplasms only rarely cause such a condition, the possibility of gastrointestinal bleeding due to this condition should be carefully taken into consideration when treating pancreatic disease.

Anterior extension of acute pancreatitis: CT findings

OBJECTIVE

The purpose of this study is threefold: (a) to specify the pathway of the extension of pancreatitis to the anterior abdominal wall, which is clinically famous as the Cullen sign; (b) to assess if this pattern of involvement affects a patient's prognosis; and (c) to seek its association with the inflammatory processes that take place in the vicinity of the pancreatic head.

MATERIALS AND METHODS

The CT findings of 277 patients with acute pancreatitis were retrospectively reviewed.

RESULTS

Inflammatory changes involved the anterior abdominal wall in 5 of 277 cases (1.8%) with acute pancreatitis. Inflammatory processes seemed to have been delivered to the anterior abdominal wall from the pancreatic head and the hepatoduodenal ligament and along the falciform ligament. The probable triggers of acute pancreatitis in such cases were endoscopic retrograde cholangiopancreatography in two cases, alcohol intake in one case, and one case unknown. Three of five cases had proven or suspected choledocholithiasis or cholelithiasis. All five patients got well after proper treatments for acute pancreatitis.

CONCLUSION

The results of our review suggest that the anterior extension of acute pancreatitis does not directly mean extensive retroperitoneal involvement of the phlegmon or pseudocysts nor fatal prognosis either and that this style of extension might be associated with inflammatory processes that occur around the pancreatic head.

[Enhanced delineation of the pancreatic duct in MR cholangiopancreatography (MRCP) with a combined use of secretin]

Magnetic resonance cholangiopancreatography (MRCP) is a method that can depict the main pancreatic duct non-invasively; however, its tendency to overestimate ductal stenosis is being noted. The authors used secretin to stimulate the output of pancreatic juice, which increased the signal of the main pancreatic duct and consequently minimized the occurrence of pseudostenosis artifacts in MRCP. MRCP images of 54 patients suspected of having pancreatic disease were visually evaluated by two observers before and after administration of secretin (1 clinical unit/kg). Improved delineation of the main pancreatic duct (68.5-59.3%, p < 0.05) and its side branches (40.7-29.6%, p < 0.05) was obtained with good interobserver agreement (kappa = 0.71-0.68).

Breath-hold MR cholangiopancreatography with a long-echo-train fast spin-echo sequence and a surface coil in chronic pancreatitis

PURPOSE

To assess heavily T2-weighted breath-hold magnetic resonance cholangiopancreatography (MRCP) for imaging the pancreatic duct in patients with chronic pancreatitis.

MATERIALS AND METHODS

Thirty-nine patients with chronic pancreatitis were examined with a breath-hold fast spin-echo (FSE) sequence employing an echo train length of 32 and with a surface coil. Results were compared with those of endoscopic retrograde cholangiopancreatography (ERCP).

RESULTS

MRCP showed the head, body, and tail of the pancreatic duct well in 79%, 64%, and 53% of cases, respectively. Agreement between MRCP and ERCP was 83%-92% in cases of ductal dilatation, 70%-92% in cases of ductal narrowing, and 92%-100% in cases of filling defects. Interobserver variation was low (kappa > 0.5) for most findings.

CONCLUSION

Breath-hold MRCP with an FSE technique depicts the pancreatic duct well in patients with chronic pancreatitis and demonstrates narrowing, dilatation, and filling defects with moderate to high accuracy.

[Breath hold MR cholangio-pancreatography (MRCP) using long echo train length fast spin echo sequence in combination with surface coil]

To test the feasibility of MR cholangio-pancreatography (MRCP) using long echo train length (32) fast spin echo sequence in combination with shoulder surface coil, 20 patients who had had ERCP were examined. Good correlations were acquired between the findings obtained by two modalities in terms of ductal strictures, dilatations and intraductal lesions. MRCP was considered to be an examination of choice in various kinds of pathologies affecting biliary duct as well as pancreatic duct for its non-invasiveness and reasonable image quality.

Clinical significance of serum ferritin determination for hepatocellular carcinoma

The clinical significance of serum ferritin as a serological marker of hepatocellular carcinoma (HCC) was studied. Fasting serum ferritin levels were measured in 343 patients with diseases of the liver, using a radioimmunoassay ferritin kit. Elevated ferritin levels were obtained in various liver diseases but hyperferritinemia could be more clearly interpreted by classifying ferritin levels according to serum iron or transaminase values. Significantly higher values were obtained in HCC than liver cirrhosis. Sensitivity for diagnosis of HCC increased by serial and simultaneous determinations of ferritin and alpha-fetoprotein because high ferritin levels were observed more often in low alpha-fetoprotein-producing HCC and also in HBsAg negative, alcohol related, small-sized HCC. Therefore, simultaneous determination of alpha-fetoprotein and ferritin seems to be useful for detection of HCC in high risk patients such as those with liver cirrhosis.

Diagnostic ability of hepatobiliary scintigraphy

Morphological aspects of biliary images were observed by the hepatobiliary scintigraphy using 99mTc-PI (pyridoxylidene isoleucine). Our study was made mainly on the diagnostic ability of the scintigram in various hepatobiliary diseases. Diagnostic findings were observed in 53.8% of the cases with intrahepatic stones and all cases with cholangioma. In the stone of the common bile duct and extrahepatic biliary cancer, the diagnostic findings were observed in 42.3% and 37.5% respectively. Hepatobiliary scintigraphy was less reliable for the diagnosis of the lesions in the gallbladder. The findings by hepatobiliary scintigraphy were as same as those by X-ray basically. In the cases showing the diagnostic finding by hepatobiliary scintigraphy, it seems to be possible to distinguish the stone from the cancer. Contrary to X-ray picture, scintigram is inferior in the image. So, it is necessary to perform ERCP or PTC to investigate fully the hepatobiliary lesions.