Carbon dioxide insufflation vs. conventional saline irrigation for peroral video cholangioscopy

BACKGROUND AND STUDY AIMS

Recent studies have evaluated the efficacy of peroral cholangioscopy (POCS) for diagnosis of biliary diseases. In order to obtain clear images with POCS, saline irrigation, which is performed to replace yellow bile, is carried out for an extended duration. The aim of this study was to evaluate the feasibility of replacing saline irrigation with CO₂ insufflation during POCS.

PATIENTS AND METHODS

A total of 36 patients who had bile duct lesions and were due to undergo POCS were enrolled in the study. Of these patients, 18 underwent POCS using saline irrigation followed by CO₂ insufflation, and 18 patients underwent the reverse approach. The two methods were compared with regard to the time required to obtain a clear endoscopic image and the quality of the images.

RESULTS

The median time required to obtain a clear endoscopic image using CO₂ insufflation (5.0 min) was significantly shorter than that required for saline irrigation (22.5 min; P < 0.001). The quality of the endoscopic images obtained was similar in 27 cases. However, CO₂ insufflation provided better images in four cases that showed an abundance of mucin or biliary sludge, and saline irrigation was superior to CO₂ insufflation in five cases that showed severe stricture with bleeding and tall papillary lesions.

CONCLUSIONS

CO₂ insufflation during POCS can reduce procedure time and simplify cholangioscopy. The overall image quality was similar to that obtained with conventional saline irrigation.

Development of a thick CdTe detector for BNCT-SPECT

As well known, it is difficult to know the exact treatment effect of boron neutron capture therapy (BNCT). It depends on the irradiation time, which is changed rather flexibly. At present, it is once fixed before BNCT. Then the actual stopping time is adjusted during BNCT by some means like activation foils. The author's group hence started development of a single-photon emission computed tomography (SPECT) system for BNCT to know the effect of BNCT in real time. By adopting a side surface (1×2 mm(2)) of a CdTe detector (1×2×20 mm(3)) as radiation entrance window, acceptable spatial resolution and high detection efficiency were simultaneously achieved. Also in about 30 min acceptable number of counts for 478 keV gamma-rays could be expected. In addition, employing a Schottky type detector the energy resolution could be improved. Discrimination of 478 keV and annihilation gamma-rays would thus be successfully made. In the next phase, it is planned to design and develop an array type detector to be implemented in the BNCT-SPECT system.

Endoscopic hemostasis using covered metallic stent placement for uncontrolled post-endoscopic sphincterotomy bleeding

Severe bleeding following endoscopic biliary sphincterotomy (EBS) can sometimes be difficult to manage, resulting in the need for an invasive intervention. The aim of this study was to retrospectively evaluate the feasibility and efficacy of endoscopic hemostasis using covered self-expandable metallic stents (SEMSs) for severe post- EBS bleeding. Eleven patients with bile duct stones underwent standard EBS using a standard sphincterotome-based technique at 4 endoscopic units of a university-affiliated hospital and a general hospital. Monotherapy or combined therapy were used to achieve hemostasis with either balloon tamponade, hypertonic saline epinephrine injection, or endoclip placement. When active bleeding could not be controlled, covered SEMSs were placed across the major papilla. Emergency endoscopy was performed on the day of admission or the subsequent day (ranging from 6 to 35 h after admission). Bleeding was classified as mild in 6 cases (54.5 %) and moderate in 5 (45.5 %). A covered SEMS 10mm in diameter and 6 cm long was placed across the papilla. After placement, complete hemostasis was achieved. The mean duration of stent placement was 8.2 days (range 5–10 days), and the SEMS was successfully removed in all cases. Although the present study has the limitations of a small sample size and lack of control patients, covered SEMS placement for endoscopic hemostasis may be useful in selected patients with uncontrolled post-EBS bleeding.

Partial paternal uniparental disomy of chromosome 6 in monozygotic twins with transient neonatal diabetes mellitus and macroglossia

Transient neonatal diabetes mellitus (TNDM) usually develops within the first few weeks of life and resolves at a median age of 3 months. In most of the cases, TNDM is caused by the over-expression of a paternally expressed imprinted PLAGL1 locus on chromosome 6q24. The most frequent manifestation other than TNDM is intrauterine growth retardation (IUGR), and in some cases macroglossia. We investigated monozygotic twins who had macroglossia without IUGR. Both of the twins developed insulin-dependent hyperglycemia within the first week of life, which subsequently resolved. DNA profiling with polymerase chain reaction amplification was performed for polymorphic microsatellite markers of chromosome 6. The six informative markers, located between 6p24 and 6q15, showed normal biparental inheritance. However, the six distal informative markers, located between 6q23.2 and the 6q telomeric region, showed the absence of a maternal allele and the presence of a single paternal allele. The monosomy of the 6q telomeric region was not confirmed by chromosome banding showing 46, XX. These findings provide further evidence that partial paternal uniparental disomy of chromosome 6 (pUPD6) causes TNDM. The phenotypes other than diabetes observed in patients with partial pUPD6 may differ from those observed in patients with complete pUPD6.

Characterization of aortic aneurysms in cardiovascular disease patients harboring Porphyromonas gingivalis

OBJECTIVE

Porphyromonas gingivalis was recently shown to cause intimal hyperplasia in a mouse model by a novel cholesterol-independent mechanism, suggesting to be a pathogen-specific feature of cardiovascular diseases. The aim of this study was to characterize the clinical and histopathological features of aortic aneurysms in cardiovascular disease patients harboring oral P. gingivalis.

SUBJECT AND METHODS

Aortic aneurysm specimens were collected from 76 Japanese patients who underwent surgery, of whom dental plaque specimens were also collected from 31 patients. Bacterial DNA was extracted from each specimen to detect P. gingivalis by polymerase chain reaction. Histopathological analyses of the aortic aneurysm specimens, including immunohistochemical staining for embryonic myosin heavy chain isoform (SMemb) and S100 calcium-binding protein A9 (S100A9), were also performed.

RESULTS

The number of aneurysms occurring in the distal aorta was significantly higher in subjects positive for P. gingivalis in dental plaque compared with those who were negative. The expressions of S100A9 and SMemb were also significantly greater in the subjects positive for P. gingivalis in dental plaque. On the other hand, there were no significant differences in adipocellular accumulation between the groups.

CONCLUSIONS

These results suggest that aortic aneurysms in patients harboring oral P. gingivalis have greater expression of S100A9 and proliferative smooth muscle cells, which was different from the present patients without oral P. gingivalis.

Reexamination of diversifying selection of polymorphic allozyme genes by using population cages in Drosophila melanogaster

Several investigators have reported increased heterozygosity for allozyme markers in laboratory experiments simulating a variable environment and have concluded that there is diversifying selection for allozyme variants. We found no change in heterozygosity in 28 large population cages where temperature, food, and light were each set at three levels, two constant and one variable, in a factorial design. Specifically, there was no change in heterozygosity when 0, 1, 2, or 3 factors were variable. The discrepancy between our negative results and earlier positive ones is that our experiments were started from a large caged population of flies which had been maintained for 6 years-long enough to be very near to linkage equilibrium. We suggest that the earlier results may have been the result of linkage between neutral, or nearly neutral, allozyme markers and selected loci or in some cases, inversions.

Repressor of P elements in Drosophila melanogaster: Cytotype determination by a defective P element carrying only open reading frames 0 through 2

The P element is a type of transposable element in Drosophila melanogaster. Characteristics of the syndrome of "hybrid dysgenesis" are due to transposition of P elements, and the molecular mechanism for regulation of this transposition has been unknown. In this study a Q strain (which carries only defective P elements in its genome but still is able to repress the transposition of complete P elements although defective in transposase activity) was used to determine the structure of the P element with this repressor (or P cytotype-determining) domain. Examination of the cytotype and structure of the P elements of particular strains with reduced copy number of P elements showed that the P element with a repressor domain was defective, being deleted between bases 1991 and 2448. This region corresponds to most of the third intron [between open reading frame (ORF) 2 and ORF 3] as well as half the ORF 3 of an intact P element. Therefore ORF 3 was deemed to be unnecessary for repressor production.

The Genetic Structure of Natural Populations of DROSOPHILA MELANOGASTER. Xiv. Effects of the Incomplete Dominance of the IN(2LR)SM1 (Cy) Chromosome on the Estimates of Various Genetic Parameters

Recent reports (Mukaiet al. 1974; Katz and Cardellino 1978; Cockerham and Mukai 1978) have indicated that the Cy chromosome is not always dominant over its homologous chromosome with respect to viability. Thus, the genetic parameters previously estimated using viabilities determined by the Cy method are biased. In the present paper, the biases of the estimates for the polygenic mutation rate, the degree of dominance and the homozygous load are examined. The results indicate that the biases for the mutation rate and the degree of dominance are small and that the estimate of the homozygous load relative to the average viability of the population is not biased.

Methylation-sensitive genome scanning

Imprinted genes in mammals are expressed exclusively from one of the parental alleles (1-6). This is regulated by parental-allele-specific CpG methylation. For example, H19 is methylated exclusively on the paternal allele, which is repressed, and is expressed exclusively from the maternal allele, which is unmethylated. Therefore, one way to find imprinted genes is searching for parental-allele-specific CpG methylation. Southern analysis using methylation-sensitive restriction enzymes could be used for such a purpose. However, usually only one gene can be analyzed by one Southern analysis. Moreover, Southern analysis requires one DNA probe for each analysis. These facts indicate at least 300 Southern analyses using 300 different probes are required to find only one imprinted gene, because the population of imprinted genes is estimated to be 0.3%. Therefore, this kind of analysis is not appropriate for searching for new imprinted genes, and the development of a new method that can simultaneously analyze thousands of genes was required.

Molecular analyses of bacterial DNA in extirpated heart valves from patients with infective endocarditis

BACKGROUND/AIMS

Infective endocarditis (IE) is caused by a microbial infection of the endothelial surface of the heart. Although blood culture examinations are commonly used to determine the associated bacterial species, molecular techniques, which enable rapid identification of targeted bacterial species, have recently been applied in clinical cases.

METHODS

Nine heart valve specimens from IE patients (six subacute cases and three acute cases) were extirpated and collected, then bacterial DNA was extracted. Bacterial species in the specimens were determined by two different molecular methods and the results were compared with those from a conventional blood culture technique. In addition, a comparison between the two molecular methods was carried out using known numbers of six streptococcal species.

RESULTS

The conventional blood culture method revealed the bacterial species in eight cases, while one was found to be negative. Multiple species were identified in most of the cases by both molecular methods; however, those specified by one method were not always consistent with those specified by the other. Furthermore, the species determined by the blood culture technique were not always identified by the molecular methods. We also found that the two molecular methods used in the present study were extremely sensitive to detect from 1 to 100 cells of individual oral streptococcal species.

CONCLUSION

Our results suggest that species specified by molecular methods may have disseminated incidentally into the bloodstream, so interpretation of such results should be carefully undertaken in clinical situations.

Frontal bone window improves the ability of transcranial color-coded sonography to visualize the anterior cerebral artery of Asian patients with stroke

The frontal bone window (FBW) is a promising approach in evaluating the anterior cerebral artery. The goal of the present study was to determine the rates of detection of the basal cerebral arteries by using the FBW alone and a combination of the FBW with the temporal bone window (TBW) in 163 patients. The combined application improved detection rates of A1 (58.6% versus 46.0%, P = .001) and A2 (43.6% versus 6.7%, P < .001) compared with the TBW alone.

Persistent supercurrent atom chip

Rubidium-87 atoms are trapped in an Ioffe-Pritchard potential generated with a persistent supercurrent that flows in a loop circuit patterned on a sapphire surface. The superconducting circuit is a closed loop made of a 100 microm wide molecular-beam epitaxy-grown MgB2 stripe carrying a supercurrent of 2.5 A. To control the supercurrent in the stripe, an on-chip thermal switch operated by a focused argon-ion laser is developed. The switch operates as an on/off switch of the supercurrent or as a device to set the current to a specific value with the aid of an external magnetic field. The current can be set even without an external source if the change is in the decreasing direction.

Optical gain spectra for near UV to aquamarine (Al,In)GaN laser diodes

Optical gain spectra presented for (Al,In)GaN laser diodes with lasing wavelength ranging from UV (375 nm) to aquamarine (470 nm) show a strong increase in inhomogeneous broadening, caused by Indium composition and quantum well width fluctuations which increase with Indium mole fraction. These gain spectra provides a standard data set for the calibration of microscopic many-body simulations. We demonstrate by comparison with basic simulations that the different assumptions of a global constant carrier density or of global constant quasi-Fermi levels for electrons and holes lead to a strikingly different dependency of optical gain on carrier density. For constant quasi-Fermi levels the threshold carrier density becomes insensitive to inhomogeneous broadening for realistic parameters. This is in agreement with the observation that the threshold current is nearly independent over the wavelength range from near UV to aquamarine.