Molecular association in aqueous solutions of high molecular weight poly(N-vinyl-2-pyrrolidone)

A viscosimetric method was used to investigate the molecular association in aqueous solutions of poly(N-vinyl-2-pyrrolidone), (PVP), of molecular weight 700 000. Limiting viscosity numbers [η] and Huggins constants k_H of the polymer solutions were observed to decrease upon addition of denaturing agents such as thiourea and guanidinium sulfate. Guanidinium sulfate was found to be even more effective in its denaturing action as compared to urea and thiourea. The decrease in [η] and k_H values increased with increasing concentrations of the denaturing agents. This behaviour was explained on the basis of the rupture of bridges formed by water molecules among different PVP chains, hydrogen bonding being responsible for these intermolecular associations. While no change in the [η] values was observed for PVP in 2 M thiourea solutions upon increasing the temperature from 25°C to 35 and 45°C, for the same increase in temperature the [η] values of aqueous PVP solutions showed substantial decreases. This is also attributed to the breaking of hydrogen bonds existing between PVP molecules.     

Early impact of hormone replacement therapy on vascular hemodynamics detected via ocular colour Doppler analysis

Objective: To determine the effects of hormone replacement therapy (HRT) on ocular blood flow.

Study design: In a prospective controlled study, 40 healthy women who presented to the menopause clinic between December 2000 and December 2001 were randomly assigned into the study. The HRT-receiving group was administered estradiol 17-valerate 2 mg the first 11 days, and estradiol 17-valerate 2 mg plus ciproterone acetate 1 mg the next 10 days of the monthly cycle for 6 months. The control group did not receive any HRT for 6 months. The ocular colour Doppler analysis were performed at baseline and after 3 and 6 months. The ocular Doppler analysis was performed in the first half of the cycle in the HRT-receiving group.

Results: Central retinal artery and ophthalmic artery basal Doppler index (peak systolic velocity, end-diastolic velocity, resistive index and pulsatility index) values of the two groups at the beginning of the study did not show any statistically significant difference. Both the right and the left central retinal artery pulsatility index (PI) values of the study group, who received HRT at the end of the third and sixth months, showed a statistically significant decline (paired-samples test, P < 0.05), while the decrease in the resistive indexes was not significant.

Conclusion: These results suggest that 6 months of combined hormone replacement therapy with estradiol 17-valerate 2 mg plus ciproterone acetate 1 mg improves ocular vascular Doppler indices which may be a reflection of cerebral vascular status.     

Pancreatobiliary adenosquamous carcinoma (report of two cases)

Adenosquamous carcinomas are rare malignant tumors of the pancreas and periampullary region. We present two cases of pancreatic and periampullary adenosquamous carcinoma with clinicopathologic, histo- and immunohistochemical findings. A 51-year-old and a 48-year-old man presented with right upper quadrant pain of three months duration and jaundice for two weeks. Both cases had an elevation of liver enzymes and CA 19-9. In the first case, computerized tomography showed a 3 cm-mass at the pancreatic head. In the second one, endoscopic retrograde choledocopancreatography (ERCP) revealed a mass at the ampulla Vateri localization. A pancreatoduodenectomy was performed for both cases. Gross pathologic examination displayed a solid, gray-white colored 4 cm-tumor at the pancreatic head and a solid, pink-white colored, 2 cm-tumor at the periampullary region bulging into the duodenal lumen. Microscopically, both tumors were composed of solid nests of squamous cells with pearl formation and mucin-containing glandular cells and diagnoses were adenosquamous carcinoma. Furthermore, histo- and immunohistochemical findings were consistent with microscopic diagnoses.     

The “vaccine” hubbub: Viral load comparisons of SARS-CoV-2 Delta and Omicron variants against different vaccine–booster vaccine combinations

There is a significant body of evidence showing that efficient vaccination schemes against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is helping control the coronavirus disease 2019 (COVID-19) pandemic. However, this goal cannot be achieved without real world data highlighting the impact of vaccines against viral spread. In this study, we have aimed at differentially investigating the impact of COVID-19 vaccines (CoronaVac, Pfizer/BioNTech, Astra/Zeneca Oxford, Janssen) used in North Cyprus in limiting the viral load of Delta and Omicron variants of SARS-COV-2. We have utilized real-time quantitative polymerase chain reaction cycle threshold values (Ct values) as a proxy of viral load of the two SARS-CoV-2 variants. Our results indicate that the administration of at least two doses of the messenger RNA-based Pfizer/BioNTech vaccine leads to the lowest viral load (highest Ct values) obtained for both Omicron and Delta variants. Interestingly, regardless of the vaccine type used, our study revealed that Delta variant produced significantly higher viral loads (lower Ct values) compared with the Omicron variant, where the latter was more commonly associated with younger patients. Viral spread is a crucial factor that can help determine the future of the pandemic. Thus, prioritizing vaccines that will play a role in not only preventing severe disease but also in limiting viral load and spread may contribute to infection control strategies.     

Working with the bereaved: U.S. Army experiences with nontraditional families

This paper uses a postmodern family perspective to examine the interaction between Army Casualty Assistance Officers (CAOs) and the families of deceased soldiers. The data we examine are open-ended survey responses of CAOs (N = 188) who assisted bereaved families of soldiers killed in three unrelated air disasters. Five themes emerged from our analysis of the qualitative responses: postmodern family structures, contested definitions of “significant other,” language, diversity, and emotion. These themes appear to be related to the difficult demands associated with bereavement work. We argue that the experiences of the CAO are comparable to the experiences of others who may work with the bereaved (e.g., police officers, medical workers, and disaster workers) when working in similar familial contexts.     

Mesoatrial shunt in Budd-Chiari syndrome

BACKGROUND: The operations with proven effects on survival in Budd-Chiari syndrome are shunt operations and liver transplantation. PATIENTS AND METHODS: Between 1993 and 1999 (June), 13 cases of Budd-Chiari syndrome have been treated surgically. Four cases had concomitant thrombosis of the inferior vena cava; the others had marked narrowing of the lumen due to the enlarged caudate lobe. Mesoatrial (n = 12) or mesosuperior vena caval (n = 1) shunts were constructed with ringed polytetrafluoroethylene grafts. RESULTS: The median portal pressure fell from 45 (range 32 to 55) to 20 (range 11 to 27) cm H(2)O (P <0.001). Two patients died in the early postoperative period. One patient who did not comply with anticoagulant treatment had a shunt thrombosis in the second postoperative year. The other 10 patients are alive without problems during a median 42 (range 1 to 76) months of follow-up. CONCLUSION: Mesoatrial shunt with a ringed polytetrafluoroethylene graft is effective in Budd-Chiari syndrome cases with thrombosis or significant stenosis in the inferior vena cava.