L-cysteine ethylester reverses the adverse effects of morphine on breathing and arterial blood-gas chemistry while minimally affecting antinociception in unanesthetized rats

L-cysteine ethylester (L-CYSee) is a membrane-permeable analogue of L-cysteine with a variety of pharmacological effects. The purpose of this study was to determine the effects of L-CYSee on morphine-induced changes in ventilation, arterial-blood gas (ABG) chemistry, Alveolar-arterial (A-a) gradient (i.e., a measure of the index of alveolar gas-exchange), antinociception and sedation in male Sprague Dawley rats. An injection of morphine (10 mg/kg, IV) produced adverse effects on breathing, including sustained decreases in minute ventilation. L-CYSee (500 μmol/kg, IV) given 15 min later immediately reversed the actions of morphine. Another injection of L-CYSee (500 μmol/kg, IV) after 15 min elicited more pronounced excitatory ventilatory responses. L-CYSee (250 or 500 μmol/kg, IV) elicited a rapid and prolonged reversal of the actions of morphine (10 mg/kg, IV) on ABG chemistry (pH, pCO2, pO2, sO2) and A-a gradient. L-serine ethylester (an oxygen atom replaces the sulfur; 500 μmol/kg, IV), was ineffective in all studies. L-CYSee (500 μmol/kg, IV) did not alter morphine (10 mg/kg, IV)-induced sedation, but slightly reduced the overall duration of morphine (5 or 10 mg/kg, IV)-induced analgesia. In summary, L-CYSee rapidly overcame the effects of morphine on breathing and alveolar gas-exchange, while not affecting morphine sedation or early-stage analgesia. The mechanisms by which L-CYSee modulates morphine depression of breathing are unknown, but appear to require thiol-dependent processes.

Diversity of the free helical rim flap: A case series tailoring the microsurgical technique to esthetically optimize full-thickness nasal defect reconstructions

INTRODUCTION

The free helical rim (FHR) flap offers like-with-like reconstruction for full-thickness nasal defects. A case series of nasal reconstruction using an FHR flap was presented, detailing surgical steps and refinements, as well as functional and esthetic outcomes.

METHODS AND MATERIALS

This is a retrospective cohort study of composite nasal defect reconstruction with FHR flap from August 2018 to March 2020. Descriptive data were analyzed by SPSS software.

RESULTS

Six cases were recruited, four were unilateral alar defects, one was hemi-nose, and one was ala plus tip. The average size of the defect was 2.5 × 2.8 cm2. Three FHR flaps were designed with retrograde pedicles and three with anterograde pedicles. The facial artery and veins were the recipient vessels in all cases. Vascular grafts were used in all six cases. Descending branch of the lateral circumflex femoral (DLCxF) artery and vein functioned as interposition vascular conduits in five cases. Superficial forearm vein grafts were used in one case. One patient needed flap re-exploration due to venous congestion. One patient had partial flap necrosis due to delayed infection, and one developed delayed wound dehiscence in the irradiated wound. The average follow-up was 18 months.

CONCLUSION

The FHR flap has consistent vascular anatomy. It can be raised as an anterograde or retrograde flap for a contralateral or ipsilateral inset. FHR flap can be used in extensive composite nasal defects. This case series demonstrates that interposition vascular grafts are invariably needed and the possibility of using forearm vessels as grafts instead of DLCxF artery and vein.

D-Cysteine Ethyl Ester Reverses the Deleterious Effects of Morphine on Breathing and Arterial Blood-Gas Chemistry in Freely-Moving Rats

Cell-penetrant thiol esters including the disulfides, D-cystine diethyl ester and D-cystine dimethyl ester, and the monosulfide, L-glutathione ethyl ester, prevent and/or reverse the deleterious effects of opioids, such as morphine and fentanyl, on breathing and gas exchange within the lungs of unanesthetized/unrestrained rats without diminishing the antinociceptive or sedative effects of opioids. We describe here the effects of the monosulfide thiol ester, D-cysteine ethyl ester (D-CYSee), on intravenous morphine-induced changes in ventilatory parameters, arterial blood-gas chemistry, alveolar-arterial (A-a) gradient (i.e., index of gas exchange in the lungs), and sedation and antinociception in freely-moving rats. The bolus injection of morphine (10 mg/kg, IV) elicited deleterious effects on breathing, including depression of tidal volume, minute ventilation, peak inspiratory flow, and inspiratory drive. Subsequent injections of D-CYSee (2 × 500 μmol/kg, IV, given 15 min apart) elicited an immediate and sustained reversal of these effects of morphine. Morphine (10 mg/kg, IV) also A-a gradient, which caused a mismatch in ventilation perfusion within the lungs, and elicited pronounced changes in arterial blood-gas chemistry, including pronounced decreases in arterial blood pH, pO2 and sO2, and equally pronounced increases in pCO2 (all responses indicative of decreased ventilatory drive). These deleterious effects of morphine were immediately reversed by the injection of a single dose of D-CYSee (500 μmol/kg, IV). Importantly, the sedation and antinociception elicited by morphine (10 mg/kg, IV) were minimally affected by D-CYSee (500 μmol/kg, IV). In contrast, none of the effects of morphine were affected by administration of the parent thiol, D-cysteine (1 or 2 doses of 500 μmol/kg, IV). Taken together, these data suggest that D-CYSee may exert its beneficial effects via entry into cells that mediate the deleterious effects of opioids on breathing and gas exchange. Whether D-CYSee acts as a respiratory stimulant or counteracts the inhibitory actions of µ-opioid receptor activation remains to be determined. In conclusion, D-CYSee and related thiol esters may have clinical potential for the reversal of the adverse effects of opioids on breathing and gas exchange, while largely sparing antinociception and sedation.

High-power structured laser modes: manifestation of quantum Green's function

The distributions of resonant frequencies in an astigmatic cavity are theoretically confirmed to be analogously equivalent to the quantum energy structures of two-dimensional commensurate harmonic oscillators. In the first part [Opt. Lett.45, 4096 (2020)OPLEDP0146-959210.1364/OL.399251] of this two-part series study, the lasing modes were verified to reveal a variety of vortex array structures. Here, in the second part of this two-part series study, the lasing modes are confirmed to agree very well with the quantum Green's functions that correspond to a bundle of Lissajous figures in the high-order regime.

High-power structured laser modes: direct generation of a vortex array

The frequency degeneracy induced by the astigmatism in a nearly hemispherical cavity is originally exploited to generate vortex array laser modes with the output power up to 300 mW. The inhomogeneous Helmholtz equation is employed to derive the wave function for manifesting the characteristics of the lasing modes. The theoretical wave function explicitly reveals the role of the Gouy phase in the formation of vortex arrays. Numerical analyses are further performed to confirm that the thermal lensing effect in the laser crystal assists the lasing transverse order to increase with increasing pump power. It is believed that the high efficiency enables the present laser modes to be useful in the applications of structured vortex beams.

Integral-based parallel algorithm for the fast generation of the Zernike polynomials

The integral representation of the Zernike radial functions is well approximated by applying the Riemann sums with a surprisingly rapid convergence. The errors of the Riemann sums are found to averagely be not exceed 3 ×10^-14, 3.3×10^-14, and 1.8×10^-13 for the radial order up to 30, 50, and 100, respectively. Moreover, a parallel algorithm based on the Riemann sums is proposed to directly generate a set of radial functions. With the aid of the graphics processing units (GPUs), the algorithm shows an acceleration ratio up to 200-fold over the traditional CPU computation. The fast generation for a set of Zernike radial polynomials is expected to be valuable in further applications, such as the aberration analysis and the pattern recognition.

Origin of continuous curves and dotted spots in laser transverse modes with geometric structures

The transverse structures of geometric modes in degenerate laser resonators with large astigmatism are systematically investigated by starting from the Gaussian wave packet formulation with ray-wave connections. The overlapping degree D between Gaussian wave packets is derived as an analytic expression that manifests the critical overlapping with D=1. The transverse patterns are confirmed to display a structure of continuous curves or dotted spots, depending on D>1 or D<1, respectively. A thorough comparison between experimental results and numerical calculations is performed to validate the theoretical analysis.

Generalized wave-packet formulation with ray-wave connections for geometric modes in degenerate astigmatic laser resonators

The parametric equations for periodic rays in degenerate astigmatic laser resonators are derived in a generalized way. The derived parametric equations clearly reveal the formation of Lissajous geometric modes with phase variation along the propagation. Using the representation of a quantum coherent state, a generalized wave-packet formula is derived to connect with the periodic rays of geometric modes. The derived wave-packet formula is not only validated through comparing with various experimental patterns, but also is directly exploited to manifest the spatial asymmetries of Lissajous lasing modes due to a highly transmissive output coupler.

Underwater polypectomy without submucosal injection for colorectal lesions ≤ 20 mm in size-a multicenter retrospective observational study

BACKGROUND

Underwater polypectomy (UWP) of large (≥ 20 mm) colorectal lesions is well described, but reports of UWP for lesions ≤ 20 mm in size, which account for > 95% of polyps encountered in routine clinical practice, are limited. We assessed the feasibility of UWP in routine practice across various sites for colorectal lesions ≤ 20 mm in size.

METHODS

A multicenter retrospective study was performed on pooled data from nine colonoscopists at 3 U.S., 1 Taiwanese and 2 Italian sites. Outcomes related to UWP on lesions ≤ 20 mm in size were analyzed.

RESULTS

In 117 patients, UWP netted 169 lesions. Polypectomy by hot (HSP, 54%) or cold (CSP, 41%) snare, and cold forceps (CFP, 5%) were performed successfully without endoscopic evidence of residual neoplasia or immediate clinically significant adverse events. The majority (74.6%) were tubular adenomas; 60.9% were from the proximal colon. Histopathologic margins were positive in 4 and unavailable in 26 CSP and 24 HSP specimens. The remainder had negative resection margins on pathologic reports.

CONCLUSION

UWP for colorectal lesions ≤ 20 mm in routine practice across multiple sites confirms the feasibility and acceptability of this technique. Improvement of resection outcomes by UWP in routine practice deserves further evaluation in a randomized controlled trial.

Wave representation for asymmetric elliptic vortex beams generated from the astigmatic mode converter

An analytical wave representation is derived to express the asymmetric elliptic vortex beams generated by using an astigmatic mode converter to transform the asymmetric Hermite-Gaussian modes. The effect of the spatial asymmetry on the elliptic vortex beam can be straightforwardly considered in the analytical wave representation. A detailed comparison with experimental intensity patterns and phase structures is made. The good agreement between experimental results and theoretical analyses confirms the characterization and generation of the asymmetric elliptic vortex beams.

Exploring elliptical vortex beams with the spatial damping effect

A general integral formula is analytically derived to represent the wave function of elliptical vortex modes. The derived formula can be straightforwardly employed to take account of spatial damping to explore vortex structure. Spatial damping is found to cause the central degenerate singularity of the circular vortex mode to be split into several singularities with different topological charges. For the non-circular vortex beam, the influence of spatial damping on the distribution of singularities is not significant. Theoretical analyses are confirmed to agree very well with the experimental measurements.

Generating high-power asymmetrical Laguerre-Gaussian modes and exploring topological charges distribution

We employ an off-axis pumped Nd:YVO₄ laser and control the reflectance of output coupler to directly generate asymmetrical Hermite-Gaussian (HG) modes with various transverse orders. By using an astigmatic mode converter, the generated asymmetrical HG modes are straightforwardly transformed into asymmetrical Laguerre-Gaussian (LG) modes with a crescent-like shape. The average output power of all the crescent-shaped LG modes can exceed 1W at the pump power of 4W. Furthermore, experimental results are theoretically verified by resonant modes derived from the inhomogeneous Helmholtz equation with the localized source distribution. Theoretical resonant modes are also used to explore the dependence of the phase structures of LG modes on the system loss. As the loss increases, it is found that the singularities at the origin will be rearranged and new singularities are formed in the outside region with average orbital angular momentum remaining unchanged.

Characterization and generation of high-power multi-axis vortex beams by using off-axis pumped degenerate cavities with external astigmatic mode converter

The generalized geometric mode with several high-order Hermite-Gaussian (HG) beams localized on ray periodic orbits in the degenerate resonator is generated by an off-axis pumped Nd:YVO₄ laser, by performing beam transformation via an astigmatic mode converter, the generalized geometric modes are found that can be converted into the multi-axis vortex beams with the bundled-rings structures. Experimental results reveal that the generated multi-axis vortex beams can preserve quite stable beam structures even under high-power operation. Moreover, the radius of the bundled rings for the multi-axis vortex beams can be flexibly adjusted by the off-axis pumping to lead to vortex structures with easily controlled orbital angular momentum distribution. The good agreement between the experimental and theoretical results of propagation evolution for the astigmatic transformation of generalized geometric modes further verify the feasibility of using the proposed system to realize various high-powered, multi-center vortex beams with good reliability and predictability.

Mobile nucleic acid amplification testing (mobiNAAT) for Chlamydia trachomatis screening in hospital emergency department settings

Management of curable sexually-transmitted infections (STI) such as Chlamydia can be revolutionized by highly sensitive nucleic acid testing that is deployable at the point-of-care (POC). Here we report the development of a mobile nucleic acid amplification testing (mobiNAAT) platform utilizing a mobile phone and droplet magnetofluidics to deliver NAAT in a portable and accessible format. By using magnetic particles as a mobile substrate for nucleic acid capture and transport, fluid handling is reduced to particle translocation on a simple magnetofluidic cartridge assembled with reagents for nucleic acid purification and amplification. A mobile phone user interface operating in tandem with a portable Bluetooth-enabled cartridge-processing unit facilitates process integration. We tested 30 potentially Chlamydia trachomatis (CT)-infected patients in a hospital emergency department and confirmed that mobiNAAT showed 100% concordance with laboratory-based NAAT. Concurrent evaluation by a nontechnical study coordinator who received brief training via an embedded mobile app module demonstrated ease of use and reproducibility of the platform. This work demonstrates the potential of mobile nucleic acid testing in bridging the diagnostic gap between centralized laboratories and hospital emergency departments.

Extracting trajectory equations of classical periodic orbits from the quantum eigenmodes in two-dimensional integrable billiards

The trajectory equations for classical periodic orbits in the equilateral-triangular and circular billiards are systematically extracted from quantum stationary coherent states. The relationship between the phase factors of quantum stationary coherent states and the initial positions of classical periodic orbits is analytically derived. In addition, the stationary coherent states with noncoprime parametric numbers are shown to correspond to the multiple periodic orbits, which cannot be explicable in the one-particle picture. The stationary coherent states are further verified to be linked to the resonant modes that are generally observed in the experimental wave system excited by a localized and unidirectional source. The excellent agreement between the resonant modes and the stationary coherent states not only manifests the importance of classical features in experimental systems but also paves the way to manipulate the mesoscopic wave functions localized on the periodic orbits for applications.

Exploiting broad-area surface emitting lasers to manifest the path-length distributions of finite-potential quantum billiards

Broad-area vertical-cavity surface-emitting lasers (VCSELs) with different cavity sizes are experimentally exploited to manifest the influence of the finite confinement strength on the path-length distribution of quantum billiards. The subthreshold emission spectra of VCSELs are measured to obtain the path-length distributions by using the Fourier transform. It is verified that the number of the resonant peaks in the path-length distribution decreases with decreasing the confinement strength. Theoretical analyses for finite-potential quantum billiards are numerically performed to confirm that the mesoscopic phenomena of quantum billiards with finite confinement strength can be analogously revealed by using broad-area VCSELs.

Clinical manifestations in patients with alpha-fetoprotein-producing gastric cancer

BACKGROUND

Patients with alpha-fetoprotein (afp)-producing gastric cancer have a high incidence of liver metastasis and poor prognosis. There is some controversy about clinical manifestations in these patients.

METHODS

Our study enrolled patients who, before surgery, had gastric cancer with serum afp exceeding 20 ng/mL [afp>20 (n = 58)] and with serum afp 20 ng/mL or less [afp≤20 (n = 1236)]. Clinical manifestations were compared between the groups.

RESULTS

Early gastric cancer was more frequent (30.1% vs. 4%) and advanced gastric cancer was less frequent (69.9% vs. 96%) in the afp≤20 group than the afp>20 group (p < 0.001). Liver and lymph node metastasis occurred less frequently in the afp≤20 group (4.4% vs. 27.6%, p < 0.001, and 60.7% vs. 91.4%, p < 0.001, respectively). The 1-, 3-, 5-, and 10-year survival rates of afp≤20 patients were 75.2%, 53.4%, 45.8%, and 34.6% respectively. The 1-, 3-, 5-, and 10-year survival rates of patients with afp greater than 20 ng/mL, but 300 ng/mL or less, were 46.7%, 28.9%, 17.8%, and 13.3% respectively. The 1-, 3-, and 5-year survival rates of patients with serum afp greater than 300 ng/mL were 15.4%, 7.7%, and 0% respectively. The independent predictors for survival time were afp concentration, age, peritoneal seeding, liver metastasis, lymph node metastasis, vascular invasion, TNM stage, curative surgery, serosal invasion, and Lauren classification.

CONCLUSIONS

Patients with high serum afp had a high frequency of liver and lymph node metastasis and very poor prognosis. More aggressive management with multimodal therapy (for example, chemotherapy, radiotherapy) might be needed when treating such patients.

Survivin SNP-carcinogen interactions in oral cancer

In Taiwan, oral cancer is causally associated with environmental carcinogens. Survivin is an anti-apoptotic protein and is generally considered a marker of malignancy. The current study explored the combined effect of survivin gene polymorphisms and environmental carcinogens on the risk and clinico-pathological development of oral cancer. Five single-nucleotide polymorphisms (SNPs) of survivin genes from 439 male patients with oral cancer and 424 male control participants (who did not have cancer) were analyzed. The survivin -31GG, +9194 GG, and +9809 TT homozygotes exhibited higher risk for oral cancer compared with the corresponding ancestral genotype, after adjustment for related confounders. The survivin -31, +9194, and +9809 SNPs combined with betel quid chewing and/or tobacco consumption could robustly elevate susceptibility to oral cancer. The distribution frequency of the -31 G: +9194 A: +9809 T haplotype was significantly higher in oral cancer patients than in control participants. These results suggest that survivin gene polymorphisms and their interactions with environmental carcinogens may increase susceptibility to oral cancer in Taiwanese men.

ABBREVIATIONS

AOR, adjusted odds ratio; CI, confidence intervals; PCR, polymerase chain-reaction; SNP, single-nucleotide polymorphisms.

Assessment of intervention measures for the 2003 SARS epidemic in Taiwan by use of a back-projection method

OBJECTIVES

To reconstruct the infection curve for the 2003 severe acute respiratory syndrome (SARS) epidemic in Taiwan and to ascertain the temporal changes in the daily number of infections that occurred during the course of the outbreak.

METHOD

Back-projection method.

RESULTS

The peaks of the epidemic correspond well with the occurrence of major infection clusters in the hospitals. The overall downward trend of the infection curve after early May corresponds well to the date (May 10) when changes in the review and classification procedure were implemented by the SARS Prevention and Extrication Committee.

CONCLUSION

The major infection control measures taken by the Taiwanese government over the course of the SARS epidemic, particularly those regarding infection control in hospitals, played a crucial role in containing the outbreak.

Is submucosal epinephrine injection necessary before polypectomy? A prospective, comparative study

BACKGROUND/AIMS

Polyps of the gastrointestinal tract are usually removed due to their link to bleeding, obstruction and malignancy. However, complications may occur following polypectomy. The aim of this study was to assess whether submucosal epinephrine injection before polypectomy could reduce the incidence of bleeding and perforation.

METHODOLOGY

Between June 1997 and November 1999, patients with sessile polyps of the gastrointestinal tract found in our endoscopic unit were randomized to receive submucosal epinephrine injection (epinephrine group) or no injection (control group) before polypectomy. In the epinephrine group, epinephrine (1:10,000) was injected surrounding the stalk of the polyp until the mucosa was blanched and bulged. The patients were observed for complications in the following month.

RESULTS

A total of 120 patients with 151 sessile polyps were enrolled in this study. In the epinephrine group, 75 polyps (n = 68) were randomized to receive epinephrine injection before polypectomy. In the control group, 76 polyps (n = 61) underwent polypectomy without epinephrine injection. In both groups, there was no significant difference in clinical features including the sizes of the polyps and their stalks, the location of polyps and the pathological diagnosis. There were a total of nine episodes of post-polypectomy hemorrhage, two in the epinephrine group and seven in the control group (2/75 vs. 7/76) (P = 0.07). One case in the epinephrine group experienced delayed bleeding (4 days later). Immediate hemorrhage occurred less in the epinephrine group than that in the control group (1/75 vs. 7/76, P = 0.03). There was one case of perforation in each group.

CONCLUSIONS

Epinephrine injection prior to polypectomy is effective in preventing immediate bleeding.

The organic precursors affecting the formation of disinfection by-products with chlorine dioxide

The object of this research was to study the formation of disinfection by-products by using chlorine dioxide (ClO2) as a disinfectant reacting with different properties of organic substance in natural aquatic environment. The adsorbent resin (XAD-4, XAD-7) was used to divide the organic matters in raw water into three groups. The influence of the function groups on structure, reaction tendency, and formation of disinfection by-products generated by the reaction of these organic substances with chlorine dioxide was explored. The experimental results show that the three different organic groups formed using adsorbent resin were hydrophobic substance, hydrophilic acid, and non-acid hydrophilics in proportions of 43%, 41%, and 16%, respectively. Within the raw water in our study, the hydrophilic substance had a higher distribution proportion than that described in general articles and journals, which indicates that this water was contaminated with pollution from human beings. The exploration of the reactivity of the three different organic substances with chlorine dioxide shows that the unit consumption of disinfection agent per unit organic matters (represented by ClO2/DOC) is in the following sequence hydrophobic substance > hydrophilic substance > non-acid hydrophilics. It indicated that larger molecular organic precursors had larger consumption of disinfectant. We also discovered that after the reaction of the three different organic substances with chlorine dioxide, the largest amount of disinfection by-products were generated by the non-acid hydrophilics.

Progression of active trachoma to scarring in a cohort of Tanzanian children

Risk factors for the incidence of scarring are needed to inform trachoma control programs in countries hyperendemic for this blinding disease. A cohort of pre-school children with constant, severe trachoma, and an age, sex, and neighborhood matched cohort of children without constant severe trachoma were followed for seven years to determine the incidence of scarring. The incidence of scarring in the children with constant severe trachoma was 29.2% versus 9.6% in the comparison group. In a model adjusting for multiple factors, significant predictors of scarring were increasing age, female, and constant severe trachoma (OR = 4.85, 95% CL = 2.05, 11.40). Infection with C. trachomatis at follow up was also associated with scarring in both groups of children. It is likely that these children have a different host response to infection, and represent a subgroup at high risk for the blinding complications of trachoma. Reducing exposure to infection in the community through antibiotics and changes in hygiene practices is still the most promising control strategy.

OmpA genotypic evidence for persistent ocular Chlamydia trachomatis infection in Tanzanian village women

BACKGROUND

Trachoma is still a significant problem in the developing world. Adult women are at higher risk of developing scarring and trichiasis, the potentially blinding sequelae, compared to men. In part, the higher risk may be due to more frequent infections in women because of their frequent contact with children, the main reservoir of C. trachomatis infection. However, other factors associated with infection, particularly constant infection, in adult women need to be identified.

METHODS

A group of 118 women who were infected with C. trachomatis and 118 women who were not infected, but of similar age and trachoma status, were identified in 1996 from a population-based sample of women age 16 and older from eleven villages in Kongwa, Tanzania. This group of 236 was re-contacted three years later to ascertain trachoma status and determine infection status using polymerase chain reaction-enzyme immunoassay (PCR-EIA). Positive samples at both time points were examined for serovar and genotype shift, using ompA sequencing information.

RESULTS

Of the original 236 women, 165 (70%) completed exams in 1999. Fifty-eight (35%) of the 165 women were excluded from this analysis because they received antibiotic treatment for trachoma in the six months prior to the second exam. Infection at baseline was the most important predictor of infection three years later (Age-adjusted odds ratio (95% confidence interval) 6.6 (1.8-24.4)). A total of 17 women (16%) were infected at the two examinations, and of the 15 for whom genotyping could be done, 11 (73%) were infected with the same ompA genotype at both time points. Chronically infected women were more likely to have trichiasis, scarring, and active trachoma at baseline than those never infected or infected only once. Only 41% of the chronically infected women were living in houses with infected pre-school children, but 24% were in houses with no children. Four of ten women with trichiasis developed incident corneal opacity over the three years.

CONCLUSIONS

The data provide evidence for persistence of infection in a sub-group of women. The strongest predictor of infection at follow-up was baseline infection, and most were infected with the same genotype at both time points. For women with persistent infection, at least half were either not living with children or not living with infected children, suggesting that continual re-exposure from a close family member was less likely. Chronic infection is likely related to both exposure and immunological factors, and these need to be further identified. Inclusion of women in community-based treatment programs, regardless of whether a child is present in the house, is likely to be important in preventing the progression of inflammatory trachoma and scarring to trichiasis.

A 3-day anti-Helicobacter pylori therapy is a good alternative for bleeding peptic ulcer patients with Helicobacter pylori infection

BACKGROUND/AIMS

One-week triple therapy has been recommended as a standard regimen for eradicating Helicobacter pylori infection. The emergence of antibiotic-resistant strains, adverse drug effects, poor compliance and high cost of therapy add problems to the management of these patients. In this study, we assessed whether a 3-day triple therapy could be effective in eradicating Helicobacter pylori infection in bleeding peptic ulcer patients.

METHODOLOGY

Peptic ulcer patients with Helicobacter pylori infection were enrolled in this study. Patients enrolled at the outpatient department (group A) received a 7-day oral regimen: bismuth subcitrate colloid 300 mg + amoxicillin 500 mg + metronidazole 250 mg four times per day. Patients who were admitted to the wards due to peptic ulcer bleeding (group B) received a 3-day regimen including omeprazole 40 mg intravenously every 6 hours, amoxicillin 500 mg + metronidazole 250 mg orally four times daily after hemostasis had been achieved. Patients of both groups received omeprazole 20 mg once per day or cimetidine 400 mg twice daily per os for at least-one month after anti-Helicobacter pylori therapy. We followed every patient endoscopically two months after anti-Helicobacter pylori therapy.

RESULTS

From June 1997 to April 1999, a total of 57 patients (30 in group A and 27 in group B) with gastric or duodenal ulcer and Helicobacter pylori infection completed anti-Helicobacter pylori therapy. Two months after anti-Helicobacter pylori therapy, peptic ulcer was found to be healed with a scar in 26 (86.7%) of group A and 23 (85.2%) of group B (P > 0.1). The eradication rates of Helicobacter pylori in the two groups were not significantly different in an intention-to-treat analysis [group A: 78.8% (26/33), 95% CI: 64.9-92.7%; group B: 80% (24/30), 95% CI: 65.7-94.3%, P > 0.1] and in a per protocol analysis [group A: 86.7% (26/30), 95% CI: 74.5-98.9%, group B: 88.9% (24/27), 95% CI: 77.1-100.7%, P > 0.1]. Fewer side effects occurred in group B (3/30) than those in group A (7/33) (P > 0.1).

CONCLUSIONS

In patients with peptic ulcer bleeding a 3-day anti-Helicobacter pylori therapy is a good alternative for eradicating Helicobacter pylori infection.

The effect of density-dependent treatment and behavior change on the dynamics of HIV transmission

In this work, we propose a model for heterosexual transmission of HIV/AIDS in a population of varying size with an intervention program in which treatment and/or behavior change of the infecteds occur as an increasing function of the density of the infected class in the population. This assumption has socio-economic implications which is important for public health considerations since density-dependent treatment/behavior change may be more cost-saving than a program where treatment/behavior change occurs linearly with respect to the number of infecteds. We will make use of the conservation law of total sexual contacts which enables us to reduce the two-sex model to a simpler one-sex formulation. Analytical results will be given. Unlike a similar model with linear treatment/behavior change in Hsieh (1996) where conditions were obtained for the eradication of disease, we will show that density-dependent treatment/behavior change cannot eradicate the disease if the disease is able to persist without any treatment/behavior change. This work demonstrates the need to further understand how treatment/behavior change occurs in a society with varying population.

Determinants of trachoma endemicity using Chlamydia trachomatis ompA DNA sequencing

A six-year prospective study of Chlamydia trachomatis infection and ocular disease in Tanzanian village children was conducted to identify the determinants of trachoma endemicity using sequencing of ompA. Overall, 749 conjunctival samples were obtained, with 176 children sampled in both 1989 and 1995. 31.1% (233/749) were positive by PCR-enzyme immunoassay, and 76% (176/233) of the positives were sequenced in variable domains (VD) 1 to 4 (22 children in both 1989 and 1995). Twenty-six ompA genotypes of serovar A, and 19 of B/Ba were identified, and only 20% of genotypes identified in 1995 matched those found in 1989. In particular, B/Ba genotypes exhibited a 15-base region in VD 2 with increased nucleotide substitution, and these types were associated with age and water availability. Homotypic infection and infection with multiple genotypes and high chlamydial load did predict subsequent severe trachoma (odds ratio (OR) = 10.14, 95% confidence interval (CI): 1.71, 60.23; OR = 6.40, 95% CI: 0.75, 54.41; OR = 6.74, 95% CI: 0.82, 55.38, respectively). And, multitypic infection was clustered with residence of village and associated with familial cattle ownership. In conclusion, high ompA polymorphism and the inability of some hosts to clear infection with the same ompA genotype suggest two distinct but converging mechanisms of endemic severe trachoma.

The formation of disinfection by-products in water treated with chlorine dioxide

In this study, chlorine dioxide (ClO(2)) was used as an alternative disinfection agent with humic acid as the organic precursor in a natural aquatic environment. The major topics in this investigation consisted of the disinfection efficiency of ClO(2), the formation of disinfection by-products (DBPs), and the operating conditions. The results indicated that the pH value (pH 5-9) did not affect the efficiency of disinfection while the concentration of organic precursors did. The primary DBPs formed were trihalomethanes (THMs) and haloacetic acids (HAAs). The distribution of the individual species was a function of the bromide content. The higher the ClO(2) dosage, the lower the amount of DBPs produced. The amount of DBPs increased with reaction time, with chlorite ions as the primary inorganic by-product.

Empirical Bayes approach to estimating the number of HIV-infected individuals in hidden and elusive populations

In this paper we estimate the numbers of intravenous drug users (IVDUs) and commercial sex workers (CSWs) in Thailand infected with human immunodeficiency virus (HIV) who have not developed acquired immunodeficiency syndrome (AIDS) directly from the semi-annual HIV serosurveillance data of Thailand from June 1993 to June 1995. We propose a 'generalized removal model for open populations' for estimating HIV-infected population size within a hidden, elusive, and perhaps high-risk population group, for all sampling time when capture probabilities vary with time. We apply empirical Bayes methodology to the generalized removal model for open populations by using the Gibbs sampler, a Markov chain Monte Carlo method. No assumption on the size of the hidden population in question is needed to implement this procedure. The statistical method proposed here requires very little computing and only a minimum of two sets of serosurvey data to obtain an estimate, thereby providing a simple and viable option in epidemiological studies when either powerful computing facilities or abundant sampling data are lacking.

The formation and control of disinfection by-products using chlorine dioxide

In this study, chlorine dioxide (ClO2) was used as an alternative disinfectant with vanillic acid, p-hydroxybenzoic acid, and humic acid as the organic precursors in a natural aquatic environment. The primary disinfection by-products (DBPs) formed were trihalomethanes (THMs) and haloacetic acids (HAAs). Under neutral conditions (pH = 7) for vanillic acid, more total haloacetic acids (THAAs) than total trihalomethanes (TTHMs) were found, with a substantial increase during the later stages of the reaction. In the case of p-hydroxybenzoic acid, the amount of THAAs produced was minimal. Raising the concentration of ClO2 was not favorable for the control of THAAs in low concentrations of vanillic acid. ClO2 could reduce the total amount of TTHMs and THAAs for higher concentration of vanillic acid. It was found that the humic acid treatment dosage was not significant. Under alkaline conditions (pH = 9), the control of TTHMs and THAAs for the treatment of vanillic acid was better and more economical, however, an appreciable amount of inorganic by-products were observed. Under the same alkaline condition, the control of THAA for the treatment of p-hydroxybenzoic acid was not beneficial and for the treatment of humic acid was not significant.

Behaviour change and treatment of core groups: its effect on the spread of HIV/AIDS

A general model is considered for treatment and behaviour change of the Human Immunodeficiency Virus (HIV) infected in a highly sexually active core group of female commercial sex workers (CSWs) and a 'bridge population' of young unpartnered males. In this model, the spread of HIV/AIDS in the community is carried out mainly through the sexual interaction between the core group and the bridge population which acts as a bridge for the spread of disease to the general population. We will consider the effect of treatment of the infected and/or the subsequent behaviour change when targeted toward the core group and the bridge population. Analytical results will be given for a strategy which targets treatment and behaviour change at either the core group or the bridge population. Numerical examples are also provided to illustrate the biological significance of the treatment/behaviour change and its effect on the threshold parameter values. The results show that if the contact rates and transmission probabilities of the treated individuals are sufficiently reduced, the treatment/behaviour change can eradicate the disease provided that the level of treatment in the infected population is sufficiently high. However, an ill-planned treatment program which fails to meet the required reductions in contact rate or transmission probability could have a detrimental effect on the spread of the epidemic.

Risk factors for trachoma: 6-year follow-up of children aged 1 and 2 years

The authors investigated the long-term stability of risk factors in predicting the presence of active trachoma and severe inflammatory trachoma in 176 children in Kongwa, Tanzania, who were aged 1 and 2 years in 1989 and were available for follow-up in 1995. Familial cattle ownership, living more than 2 hours away from a water source, and facial cleanliness at both time points were associated with the presence of active trachoma at both time points (odds ratio (OR) = 2.58, 95% confidence interval (CI): 1.15, 5.79; OR = 3.07, 95% CI: 1.23, 7.64; and OR = 0.52, 95% CI: 0.26, 1.03, respectively). An association of familial cattle ownership with facial cleanliness and water accessibility was observed. Having a clean face at both time points was associated with lower odds of active trachoma at both time points for children in non-cattle-herding families (OR = 0.40, 95% CI: 0.18, 0.87). Living more than 2 hours away from a water source at both time points increased the odds of active trachoma at both time points in children of cattle-herding families (OR = 8.00, 95% CI: 1.99, 32.10). Noticeably, severe inflammatory trachoma at baseline predicted mortality in children from villages in which trachoma was less common (OR = 3.75, 95% CI: 1.09, 12.98). The results suggest that risk factor reduction could diminish persistent disease.

Intravenous pretreatment with magnolol protects myocardium against stunning

Magnolol, an antioxidant, has been reported to possess various protective effects on the cardiovascular system. However, its effect on myocardial stunning has not been elucidated. The purpose of this study was to investigate the antistunning effect of magnolol by evaluating the recovery of regional myocardial function after 10-minute coronary artery occlusion in anesthetized, open-chest rabbits. There was no significant hemodynamic change after intravenous infusion of magnolol. Systolic wall thickening fraction (WThF) measured with an epicardial Doppler sensor in animals pretreated with normal saline and vehicle solution remained significantly depressed (60 +/- 7% and 77 +/- 4% of baseline WThF, respectively) 3 hours after coronary artery reperfusion (CAR). Pretreatment with magnolol (10(-7) and 10(-6) g/kg, intravenous infusion) significantly enhanced the recovery of systolic wall thickening fraction (98 +/- 1 and 99 +/- 1% of baseline WThF, respectively) 60 minutes after CAR. This study demonstrated that intravenous pretreatment with magnolol protected myocardium against stunning.

Life-threatening haemorrhage from a sternal metastatic hepatocellular carcinoma

Rupture of the tumour is a catastrophic complication of hepatocellular carcinoma. The prognosis in patients with a ruptured hepatocellular carcinoma is usually unfavourable. We describe a 46-year-old man who suffered from visible massive tumour haemorrhage due to a hepatitis B-related hepatocellular carcinoma that metastasized to the sternal bone. The prominent tumour mass was bulging over the anterior chest wall on the sternum of the patient, and bled spontaneously. This episode of life-threatening haemorrhage was stopped by surgical ligation of the bleeding site. Palliative radiotherapy shrank the tumour mass size and prevented further possible bleeding. This is likely to be the first reported case with a visible spontaneous tumour bleeding from a sternal metastatic hepatocellular carcinoma.

Kinetics of Fe(III) reduction by ascorbic acid in aqueous solutions

The reaction of Fe(III) and ascorbic acid (AA) in food products and digestive tracts affects the efficiency and uptake of these two nutrients. We investigated the kinetics of Fe(III) reduction by AA at pH 5 and 6 in a model system at 25 degrees C. The results indicate that the reduction of Fe(III) by AA is of zero order with respect to AA. The reaction order with respect to Fe(III) cannot be represented by a simple kinetic model at pH 5 or 6. The major stage of the reduction (about 80%, stoichiometrically), however, could be represented by a general equation of -d[Fe(III)]/dt = k[Fe(III)],(1. 811) where k is a rate constant and [Fe(III)] is the total ferric concentration. The rate constant decreased 1 order of magnitude as pH increased from 5 to 6. Aging of Fe(III) solution slows its reduction rate at pH 6 but not at pH 5.

Determination of carbon dioxide evolution rates using a novel noninstrumental microrespirometer

A novel noninstrumental microrespirometer was developed to determine carbon dioxide evolution rates of solid or liquid samples at microL/h levels accurately and rapidly. The respirometer is based on the simple principle of acid-base titration at a steady-state of carbon dioxide absorption/evolution. The structure and operation of the microrespirometer are simple and the cost is modest in comparison to instrumental methods. The microrespirometer is suitable for laboratory studies and field routine examinations of food, agricultural, and environmental samples.

The pH and anion effects on the heterogeneous photocatalytic degradation of o-methylbenzoic acid in TiO2 aqueous suspension

This investigation used UV light of 365 nm and titanium dioxide in aqueous suspension to study the photocatalytic reaction of o-methylbenzoic acid under the influence of pH values, anion additives and the varieties of titanium dioxide. From experimental results, under the condition of 5 g/l TiO2, pH 3 and light intensity of 2.45 mW/cm2, 0.1 mM of o-methylbenzoic acid could be completely decomposed in 2 h. The reaction was faster with lowering pH, and was found to be apparent first-order following Langmuir-Hinshelwood model. In the presence of anion additives, the inhibitive effect of chloride ions was larger than that of sulfate ions under acidic condition for Degussa brand titanium dioxide, but without influence using Janssen brand. Both brands, however, promoted the mineralization of o-methylbenzoic acid (o-MBA).

Detection of pork in heat-processed meat products by monoclonal antibody-based ELISA

An enzyme-linked immunosorbent assay (ELISA) using a monoclonal antibody to a porcine thermal-stable muscle protein was developed for detection of pork in cooked meat products. The assay specifically detects porcine skeletal muscle, but not cardiac muscle, smooth muscle, blood, and nonmuscle organs. No cross-reactivity was observed with common food proteins. Validity of the assay was evaluated with laboratory formulated and commercial meat samples. The detection limit was determined as 0.5% (w/w) pork in heterologous meat mixtures. Overall, intra- and inter-assay coefficients of variation were 5.8 and 7.9%, respectively. The accuracy in analyzing market samples was 100% as verified by product labeling and confirmed by a commercial polycolonal antibody test kit.

Incidence of trichiasis in a cohort of women with and without scarring

BACKGROUND

Blindness from trachoma is a significant problem for many underdeveloped countries. While active trachoma is common in children, trichiasis, the potentially blinding sequella, develops in adulthood and affects mainly women. Little is known about factors associated with the development of trichiasis.

METHODS

The 7-year incidence of trichiasis and its association with ocular chlamydia infection was examined in a cohort of women from a hyperendemic area. A total of 4,932 women 18 years and older, living in 11 villages in Central Tanzania, were examined in 1989. A follow-up examination in 1996 was performed on all women with scars living in six of the 11 villages and on a random sample of women without scars from the same villages. Trachoma was graded clinically, chlamydia infection was ascertained at follow-up using polymerase chain reaction-enzyme immunoassay (PCR-EIA).

RESULTS

A total 523 of the women with scars and 503 of the women without scars were re-examined. Forty-eight of the women with scars (incidence, 9.2%) and three of the women without scars (0.6%) developed trichiasis in the 7-year period. Prevalence of chlamydia infection was significantly higher in the group with scars (11.7% versus 7.1%). Trichiasis cases were more likely to be older, and to have chlamydia infection at follow-up odds ratio (95% confidence interval) 2.5 (1.1-5.7).

CONCLUSION

The 7-year incidence rate in the population with scars was high, over 1% per year. Ocular chlamydia infection was more common in the group with scars at baseline and was also associated with being a trichiasis case, suggesting the importance of potentially long-term chlamydia infection in the progression to trichiasis. Antibiotic distribution programmes for trachoma control should include women with scars.

Will Helicobacter pylori affect short-term rebleeding rate in peptic ulcer bleeding patients after successful endoscopic therapy?

OBJECTIVE

Helicobacter pylori (H. pylori) can augment the pH-increasing effect of omeprazole in patients with peptic ulcer. A high intragastric pH may be helpful in preventing recurrent hemorrhage by stabilizing the blood clot at the ulcer base of bleeding peptic ulcer patients. Therefore, we hypothesized that omeprazole may reduce short-term rebleeding rate in these patients with H. pylori infection after initial hemostasis had been obtained.

METHODS

Between July 1996 and December 1998, 65 bleeding peptic ulcer patients (24 gastric ulcer, 41 duodenal ulcer) who had obtained initial hemostasis with endoscopic therapy were enrolled in this trial. Thirty (46.2%) of them were found to have H. pylori infection by a rapid urease test and pathological examination. For all studied patients, omeprazole was given 40 mg intravenously every 6 h for 3 days. Thereafter, omeprazole was given 20 mg per os (p.o.) once daily for 2 months. A pH meter was inserted in the fundus of each patient under fluoroscopic guidance after intravenous omeprazole had been administered. The occurrence of rebleeding episode was observed for 14 days.

RESULTS

In patients with H. pylori infection, intragastric pH (median, 95% confidence interval [CI]: 6.54, 5.90-6.68) was higher than in those without H. pylori infection (6.05, 5.59-6.50, p < 0.001). However, the patients with rebleeding (2 vs 3), volume of blood transfusion (median, range: 1000 ml, 0-2250 vs 750, 0-2000), number of operations (0 vs 1), mortality caused by bleeding (0 vs 0), and hospital stay (median, range: 6 days, 3-14 vs 7, 5-16) were not statistically different from those without H. pylori infection.

CONCLUSIONS

Omeprazole does increase intragastric pH in bleeding peptic ulcer patients with H. pylori infection. However, the presence of H. pylori infection does not affect the short-term rebleeding rate in these patients.

Recurrent spontaneous bacterial empyema in cirrhosis: a case report

Spontaneous bacterial empyema occurs in about 0.4% of cirrhotic patients, but recurrent attack has rarely been reported. Herein we report a case of repeat episodes of spontaneous bacterial empyema. The patient presented with fever, shortness of breath and three episodes of spontaneous bacterial empyema (accompanied by septic shock in two episodes) within six months. Chest roentgenography showed massive right-side pleural effusion. Thoracentesis yielded pleural effusion containing a neutrophil count of more than 500/microliter. A blood culture grew non-O1 Vibrio cholerae in one episode and the pleural effusion culture grew Aeromonas hydrophila. A chest-tube was inserted during the latest episode due to a low pH and glucose concentration in the pleural fluid. The patient recovered well after medical treatment. The etiology, diagnosis and management of spontaneous bacterial empyema are discussed.

Development of a monoclonal antibody specific to cooked mammalian meats

Detection of species adulteration in ground meat products is important for consumer protection and food-labeling law enforcement. This study was conducted to develop monoclonal antibodies (MAbs) that can be used in an enzyme-linked immunosorbent assay (ELISA) for rapid detection of any cooked mammalian meats in cooked poultry products. Soluble muscle proteins extracted from cooked pork (heated at 100 degrees C for 15 min) were used as the antigen to immunized mice for developing the MAb. One that was developed, MAb 2F8 (IgG2b class), strongly reacted with cooked meat of five mammalian species (beef cattle, hogs, sheep, horse, and deer) but did not react with any cooked poultry (chicken, turkey, and duck) or raw meats. At least 0.5% by weight of pork, beef, lamb, and horse meats in a chicken-based mixture could not detect using the indirect ELISA with MAb 2F8. The MAb 2F8 is useful in a single initial screening test to detect the presence of five nonpoultry meat adulterants in cooked poultry products.

Severe disease in children with trachoma is associated with persistent Chlamydia trachomatis infection

The immediate study objective was to determine if variable disease severity in children with trachoma could be attributable in part to host variation in the ability to clear Chlamydia trachomatis infection. Identification of sibling cohorts with these variant phenotypes would be useful for immunogenetic studies. A weekly survey for 3 months in a trachoma-hyperendemic village using detection of chlamydial DNA and grading of disease severity indicated that 62% (33/53) of children had at least one infection episode. Of those, 64% (21/33) who were persistently infected had both significantly higher mean chlamydial DNA loads and more severe trachoma than did sporadically infected children. Of importance, duration of infection differed between siblings in 60% (6/10) of families. The results suggest that chlamydial load and duration of infection determine the chronic nature of severe disease in trachoma and that host variable efficiency for chlamydial clearance between siblings is in part determined by host variation.

Esophageal reflux after total or proximal gastrectomy in patients with adenocarcinoma of the gastric cardia

OBJECTIVES

To demonstrate gastroesophageal reflux induced by proximal gastrectomy and to report preventive measures, such as total gastrectomy followed by Roux-en-Y esophagojejunostomy.

METHODS

Thirteen patients underwent proximal gastrectomy (PG), and six patients underwent total gastrectomy (TG). Two of the 13 patients who received PG later underwent completion total gastrectomy. All patients were followed with endoscopy, radionuclide scintigraphy, and 24-h pH monitoring.

RESULTS

Endoscopic examination revealed evidence of esophagitis in all PG group patients; however, none of the TG group had esophagitis. Prolonged esophageal transit was observed in 11 patients (10 in the PG group, one in the TG group). Increased residual fraction was found in 10 patients (nine in the PG group, one in the TG group). An increase in the retrograde index was found in 14 cases (11 in the PG group, three in the TG group). Positive enterogastroesophageal reflux was identified in 11 patients (eight in the PG group, three in the TG group). Twenty-four hour pH monitoring resulted in 10 positives (10 in the PG group, none in the TG group).

CONCLUSIONS

Frequently, proximal gastrectomy will lead to significant gastroesophageal reflux and, subsequently, to varying degrees of esophagitis. The clinical symptoms are usually characteristic. However, the severity of esophagitis and the mechanism of reflux can be determined only by integrated interpretation of a reflux study. The study should include endoscopy, radionuclide scintigraphy, and 24-h pH monitoring. Although a total gastrectomy with Roux-en-Y diversion can reduce the incidence of acid reflux, neutral enteroesophageal reflux may be observed during a radioactive isotope study. Fortunately, neutral refluxes rarely cause esophagitis. A proximal gastrectomy should be avoided in adenocarcinoma of the gastric cardia, except in early cancer. Symptomatic palliation can be relieved by medication. However, completion total gastrectomy is the only effective method for eradicating unrelenting symptoms.

A two-sex model for treatment of HIV/AIDS and behaviour change in a population of varying size

In this work, we propose a model for heterosexual transmission of HIV/AIDS incorporating a community-wide screening and treatment programme. We will investigate various consistency assumptions about the conservation of heterosexual contacts, which will enable us to reduce this two-sex model to a simpler one-sex formulation. In all cases analytical results will be given with threshold parameters obtained for the persistence of disease, the persistence of total populations, and the persistence of infective populations. By comparing the theoretical results for the different variations of our model, we hope to shed some light on the effectiveness of the prevention and control measures that are needed to deal with the emerging AIDS epidemic in Third World communities with growing populations.

A model for HIV in Asia

A model is proposed in which the spread of HIV/AIDS in the community is mainly due to the sexual interaction between a core group of female prostitutes and young unmarried males. Several threshold parameters are obtained that determine persistence of endemic proportions, persistence of total population, and the persistence of infective population given the extinction of endemic proportions in a population tending to infinity. Conditions are given for the existence of multiple endemic equilibria as well as the existence of multiple stable equilibria with separatrix and their asymptotic behavior and biological significance are discussed. In all cases, global analysis is accompanied by bifurcation diagrams, and numerical examples are provided for some particular cases of interest. This model was proposed with the recent rapid growth of the HIV/AIDS epidemic in Asia in mind.