Direct measurement of hydrogen bonding in DNA nucleotide bases by atomic force microscopy.

We have used self-assembled purines and pyrimidines on planar gold surfaces and on gold-coated atomic force microscope (AFM) tips to directly probe intermolecular hydrogen bonds. Electron spectroscopy for chemical analysis (ESCA) and thermal programmed desorption (TPD) measurements of the molecular layers suggested monolayer coverage and a desorption energy of about 25 kcal/mol. Experiments were performed under water, with all four DNA bases immobilized on AFM tips and flat surfaces. Directional hydrogen-bonding interaction between the tip molecules and the surface molecules could be measured only when opposite base-pair coatings were used. The directional interactions were inhibited by excess nucleotide base in solution. Nondirectional van der Waals forces were present in all other cases. Forces as low as two interacting base pairs have been measured. With coated AFM tips, surface chemistry-sensitive recognition atomic force microscopy can be performed.     

Global Health Crisis,Global Health Response: How Global Health Experiences Prepared North American Physicians for the COVID-19 Pandemic

The COVID-19 pandemic plunged hospital systems into resource-deprived conditions unprecedented since the 1918 flu pandemic. It brought forward concerns around ethical management of scarcity, racism and distributive justice, cross-disciplinary collaboration, provider wellness, and other difficult themes. We, a group of medical educators and global health educators and clinicians, use the education literature to argue that experience gained through global health activities has greatly contributed to the effectiveness of the COVID-19 pandemic response in North American institutions. Support for global health educational activities is a valuable component of medical training, as they build skills and perspectives that are critical to responding to a pandemic or other health system cataclysm. We frame our argument as consideration of three questions that required rapid, effective responses in our home institutions during the pandemic: How can our health system function with new limitations on essential resources? How do we work at high intensity and volume, on a new disease, within new and evolving systems, while still providing high-quality, patient-centered care? And, how do we help personnel manage an unprecedented level of morbidity and mortality, disproportionately affecting the poor and marginalized, including moral difficulties of perceived care rationing?KEY WORDS: global health education, global health, medical education, COVID-19     

Zur Kasuistik des Sellheimschen Kastratoidismus

Ohne Zusammenfassung     

Plesiomonas shigelloides sepsis and splenic abscess in an adolescent with sickle-cell disease.

Plesiomonas shigelloides is a rare cause of self-limiting gastroenteritis. We report a case of extraintestinal P. shigelloides infection in an adolescent with sickle-cell disease who presented with bacteremia complicated by a splenic abscess. Despite the high mortality rate reported in extraintestinal P. shigelloides infection, the patient survived after drainage of the abscess and treatment with antibiotics.     

Magnetic cell sorting for enriching Schwann cells from adult mouse peripheral nerves

We have devised a simple method to purify mitotically active Schwann cells (SC) from peripheral nerves of adult mice. Nerves were predegenerated in vitro for 7 days and after dissociation cells were plated on poly-L-lysine/laminin coated dishes in N2 serum-free culture medium supplemented with forskolin and heregulin-beta1. Primary cultures were purified from contaminating fibroblasts by magnetic cell sorting (MACS) based on SC membrane specific expression of p75(NGFR) and enriched to about 99% of SC after MACS from 34 to 91% before sorting. After sorting, purified adult mouse SC were propagated for three passages until confluent to a total surface of 160 cm(2) per mouse (two sciatic and two trigeminal nerves). In addition, we show that this method can be used to purify tumoral SC from mouse NF2-related schwannomas.     

Determinants of willingness to donate living related and cadaveric organs: identifying opportunities for intervention

BACKGROUND: Although low rates of cadaveric organ donation have been attributed to potential cadaveric donors' concerns regarding their religious beliefs and mistrust of the health care system, it is unclear whether similar concerns are important to potential living related donors. It is also not known which factors might be most responsible for low rates of cadaveric and living related donation among the general public. METHODS: We conducted a cross-sectional study of households in Maryland, using a standardized telephone questionnaire, to assess factors associated with willingness to donate cadaveric and living related organs. We compared factors (demographic, cultural, attitudinal, and clinical) related to willingness to donate cadaveric organs with factors related to willingness to donate living related organs. In multivariate analyses, we assessed the independent relation of factors to willingness to donate cadaveric and living related organs, and we assessed the relative importance of these factors in explaining variation in the general public's willingness to donate. RESULTS: Of 385 participants (84% of randomized homes), 254 (66%) were extremely willing to donate to a sibling but only 179 (47%) had designated themselves a cadaveric donor on their drivers' licenses. In bivariate analysis, older age, comorbid conditions, mistrust in hospitals, and concerns about discrimination in hospitals were statistically significantly associated with less willingness to donate living related organs, although African-Americans, older age, lower education, lack of insurance, unemployment, comorbid conditions, and religion/spirituality were associated with less willingness to donate cadaveric organs. After adjusting for potential confounders, only mistrust in hospitals and concerns about discrimination remained strongly and independently associated with 50 to 60% less odds of willingness to donate living related organs [[relative odds [95% confidence intervals (CI)]: 0.4 (0.2-0.7) to 0.5 (0.3-1.0) and 0.4 (0.2-0.9), respectively]] although presence of dependents was associated with 70% higher odds of willingness to donate living related organs [relative odds (95% CI): 1.7 (1.0-3.0)]. In contrast, older age, employment status, religion/spirituality, and mistrust in hospitals were associated with 50 to 90% less odds of willingness to donate living related organs cadaveric organs [relative odds (95% CI): 0.3 (0.1-0.8), 0.4(0.2-0.8), 0.1 (0.1- 0.5) to 0.5 (0.2-0.9), and 0.3 (0.2-0.6), respectively]. Mistrust in hospitals and concerns about the surgical donation procedure contributed most to the variation in willingness to be a living related donor, although race contributed most to the variation in willingness to be a cadaveric donor. CONCLUSIONS: Many factors affect the general public's willingness to donate organs, but their relative contribution is different for living related versus cadaveric donation. Efforts to improve organ donation rates should be directed toward factors that are most important in explaining the existing variation in willingness to donate.     

Social and political factors influencing the functioning of regional health boards in British Columbia (Canada)

Health reform is associated with changes in the way the health system works and in the roles of major stakeholders, such as governments, health professionals, and the lay public. This paper reviews the immediate relevance of these social and political elements to health boards, particularly those with lay board members; source documents include peer-reviewed articles, and government documents and news releases in Canada especially. Also presented are the perceptions of 130 regional health board members in British Columbia (BC), Canada, who responded to our 1996 survey questionnaire. Two sets of social and political factors are identified and discussed in this paper. The first set deals with the composition of health board members (qualifications, representation, and selection). Our findings suggest that there is now less attention focusing on the composition of health boards in BC. This may contribute to a re-focusing of attention on the boards' effectiveness in working with stakeholders and in influencing the health system. The other set of social and political factors deals with the relations of health boards with key stakeholder groups. The responses to our questionnaire suggest that the health boards in BC may have had some success in addressing the concerns of various stakeholder groups. However, the respondents also suggested that the stakeholder groups needed to be more understanding and involved in the regionalization (decentralization) process. Health boards that have lay representatives, including regional health authorities in Canada, face similar social and political factors immediate to their operation.