Comparison of endoscopic balloon dilatation potency using balloons size more or less than 15 mm in the treatment of large bile duct stones: a clinical trial study

AIM

The present study was performed on patients with large bile duct stones to compare clinical outcomes and complications of balloon dilatation treatment between two sizes of balloons, < 15 mm and ≥ 15 mm.

BACKGROUND

in 1982, the endoscopic papillary balloon dilatation (EPBD) method was presented by Staritz to reduce bleeding and perforation risk of large bile duct stones.

METHODS

Patients with large bile duct stones admitted to Taleghani hospital from December 2018 to December 2019 who were the candidates for balloon dilation with limited sphincterotomy. Patients were randomly divided into two groups. In group B, a ≥ 15 mm balloon was used, and in group A, a balloon <15 mm was used. The clinical results of balloon dilation and its complications were recorded and compared.

RESULTS

Most patients had 1 or 2 large bile duct stones, and there was no significant difference in the number of stones. Extraction was successful in 92.8% of group B and 85.7% of group A without significant differences (P = 0.8). Pancreatitis, hemorrhage, cholangitis, and perfusion occurred in 8%, 4.2%, 1.4%, and 2.8% of group B subjects and also in 10%, 2.8%, 0%, and 1.4% of group A subjects, respectively, and the difference between the two groups was not significant.

CONCLUSION

Generally, this study results showed that balloon size did not have a significant effect on the success rate of bile duct stones. Moreover, considering the lack of significant association between balloon dilatation size and the occurrence of post-endoscopic complications such as pancreatitis, it seems that large-size dilatation has no serious clinical risk.

Enhanced Control of Transient Raman Scattering Using Buffered Hydrogen in Hollow-Core Photonic Crystal Fibers

Many reports on stimulated Raman scattering in mixtures of Raman-active and noble gases indicate that the addition of a dispersive buffer gas increases the phase mismatch to higher-order Stokes and anti-Stokes sidebands, resulting in a preferential conversion to the first few Stokes lines, accompanied by a significant reduction in the Raman gain due to collisions with gas molecules. Here we report that, provided the dispersion can be precisely controlled, the effective Raman gain in a gas-filled hollow-core photonic crystal fiber can actually be significantly enhanced when a buffer gas is added. This counterintuitive behavior occurs when the nonlinear coupling between the interacting fields is strong and can result in a performance similar to that of a pure Raman-active gas, but at a much lower total gas pressure, allowing competing effects such as Raman backscattering to be suppressed. We report high modal purity in all the emitted sidebands, along with anti-Stokes conversion efficiencies as high as 5% in the visible and 2% in the ultraviolet. This new class of gas-based waveguide device, which allows the nonlinear optical response to be beneficially pressure-tuned by the addition of buffer gases, may find important applications in laser science and spectroscopy.

Single-shot reconstruction of spectral amplitude and phase in a fiber ring cavity at a 80 MHz repetition rate

Femtosecond pulses circulating in a synchronously driven fiber ring cavity have complex amplitude and phase profiles that can change completely from one round-trip to the next. We use a recently developed technique, combining dispersive Fourier transformation) with spectral interferometry, to reconstruct the spectral amplitude and phase at each round-trip and, thereby, follow in detail the pulse reorganization that occurs. We focus on two different regimes: a period-two regime in which the pulse alternates between two distinct states and a highly complex regime. We characterize the spectral amplitude and phase of the pulses in both regimes at a repetition rate of 75.6 MHz and find good agreement with modeling of the system based on numerical solutions of the generalized nonlinear Schrödinger equation with feedback.

Intraosseous transcutaneous amputation prostheses versus dental implants: a comparison between keratinocyte and gingival epithelial cell adhesion in vitro

Infection is the primary failure modality for transcutaneous implants because the skin breach provides a route for pathogens to enter the body. Intraosseous transcutaneous amputation prostheses (ITAP) are being developed to overcome this problem by creating a seal at the skin-implant interface. Oral gingival epithelial cell attachment creates an infection-free seal around dental implants. However, this has yet to be achieved consistently outside of the oral environment. Epithelial cells attach to metal substrates by means of hemidesmosomes and focal adhesions. Their density per unit cell is an indicator of attachment strength. We postulate that gingival epithelial cells express more hemidesmosomes and focal adhesions at earlier time points, compared with epidermal keratinocytes, and this increased speed and strength of attachment may be the reason why an infection-free seal is often achieved around dental implants but less frequently around ITAP. The aim of this study was to compare epidermal keratinocyte with oral gingival cell attachment on titanium alloy in vitro, to determine whether these two cell types differ in their speed and strength of attachment. We aimed to test the hypothesis that gingival cells up-regulate focal adhesion and hemidesmosome formation at earlier time points compared with extra-oral keratinocytes. To test this hypothesis we cultured epidermal keratinocytes and oral gingival cells on titanium alloy substrates and assessed cell attachment by focal adhesions and hemidesmosome expression at 4, 24, 48 and 72 hours. Formation and expression of hemidesmosomes temporally lagged behind that of focal adhesions in both cell types. Gingival derived cells up-regulated focal adhesion and hemidesmosome expression at earlier time points compared with epidermal keratinocytes. Hemidesmosome expression in oral gingival cells was 3 times greater compared with epidermal keratinocytes at 4 hours. Our findings indicate that earlier attachment may be key to the success of the dental implant transcutaneous interface.