Cryo-electron tomography reveals conserved features of doublet microtubules in flagella.

The axoneme forms the essential and conserved core of cilia and flagella. We have used cryo-electron tomography of Chlamydomonas and sea urchin flagella to answer long-standing questions and to provide information about the structure of axonemal doublet microtubules (DMTs). Solving an ongoing controversy, we show that B-tubules of DMTs contain exactly 10 protofilaments (PFs) and that the inner junction (IJ) and outer junction between the A- and B-tubules are fundamentally different. The outer junction, crucial for the initiation of doublet formation, appears to be formed by close interactions between the tubulin subunits of three PFs with unusual tubulin interfaces; other investigators have reported that this junction is weakened by mutations affecting posttranslational modifications of tubulin. The IJ consists of an axially periodic ladder-like structure connecting tubulin PFs of the A- and B-tubules. The recently discovered microtubule inner proteins (MIPs) on the inside of the A- and B-tubules are more complex than previously thought. They are composed of alternating small and large subunits with periodicities of 16 and/or 48 nm. MIP3 forms arches connecting B-tubule PFs, contrary to an earlier report that MIP3 forms the IJ. Finally, the "beak" structures within the B-tubules of Chlamydomonas DMT1, DMT5, and DMT6 are clearly composed of a longitudinal band of proteins repeating with a periodicity of 16 nm. These findings, discussed in relation to genetic and biochemical data, provide a critical foundation for future work on the molecular assembly and stability of the axoneme, as well as its function in motility and sensory transduction.

Environments, processes, and outcomes - using the LEPO framework to examine medical student learning preferences with traditional and electronic resources.

Changes in medical student learning preferences help drive innovation in teaching and require schools and commercial resources to quickly adapt. However, few studies have detailed the relationship of learner preferences to the environment and teaching modalities used in the pre-clerkship years, nor do they incorporate third-party resources. Our study attempts to analyze learner preferences by comparing the use of traditional and third-party resources. In 2017-18, a survey was distributed to medical students and residents at two accredited medical schools. Participants noted preferred styles of learning regarding lecture duration, timing, location, format, third-party resources, learner types and USMLE Step 1 scores. The 'Learning Environment, Learning Processes, and Learning Outcomes' (LEPO) framework [5] was used to examine learner preferences, with responses compared using the Mann-Whitney U and two proportion z-tests. A total of 329 respondents completed the survey: 62.7% medical students and 37.3% residents. The majority of participants identified their learning style by Kolb [6] as converging (33.0%) or accommodating (39.2%). Students preferred lectures 30-40 minutes long (43.3%), during morning hours (54.2%), in their own homes (52.0%), via online lectures with simultaneous drawings (56.0%), and classroom/podcast lectures with PowerPoint® presentations (54.3%). Overall, students rated third-party resource characteristics higher than traditional curricula, including effectiveness of teachers, length, quality, time of day, and venue (p < 0.001), but also preferred small group formats. Students reported animated videos (46.6%) and simultaneous drawings (46.5%) as the most effective means of retaining information. Understanding changing learner preferences is important in creating optimal curricula for today's students. Using the LEPO framework, this study identifies critical preferences in successfully teaching medical students, inclusive of commercial and traditional resources. These results can also help guide changes in pedagogy necessary due to the more recent COVID-19 pandemic.

Predictors of cancer screening among low-income primary care patients.

Although population-based studies report lower rates of cancer screening among racial/ethnic minorities than among Whites in the U.S., few studies have examined predictors of screening among low-income Hispanic, Black, and Chinese primary care patients. We examined utilization of mammography, Pap smear, digital rectal examination, fecal occult blood testing, sigmoidoscopy/colonoscopy, and prostate-specific antigen testing in 833 patients from 2 community health centers in New York City, ascertaining relationships between use of screening and race/ethnicity, income, education, years in the U.S., insurance, cancer risk perception, family disease history, and physician recommendation. Despite similar access to primary care, Hispanics and Blacks reported higher utilization rates of all screening tests than Chinese (p<.01). Physician recommendation and more years in the U.S. were associated with greater use of all screening services (p<.001), with physician recommendation most strongly associated with screening. Interventions to enhance screening by at-risk groups should emphasize both physician recommendation and culturally-sensitive patient education.

Prevalence of overweight and obesity in Chinese American children in New York City.

Childhood obesity has been a growing concern in recent years. The extent of obesity in various ethnic pediatric populations including Chinese Americans has not been fully explored. In this study, the prevalence of overweight and obesity in a Chinese American pediatric population (6-19 years) was determined through a chart review of 4,695 patients from a large community health center in New York City. Demographic characteristics including sex, age and immigrant status were used in a logistic regression to determine risk factors for obesity in this community. Overall, 24.6% of the children studied were overweight or obese (defined as BMI > or = 85th percentile for age and sex). Among US born boys aged 6-12 years, the combined prevalence of overweight and obesity was found to be as high as 40%. Further studies are needed to understand the complex interplay of factors that contribute to obesity in pediatric immigrant groups.

Acceptance of repeat esophagogastroduodenoscopy to detect gastric cancer in a Chinese immigrant cohort.

GOAL: To study the feasibility of using repeat esophagogastroduodenoscopy (EGD) to screen for Helicobacter pylori infection and gastric cancer in an Asian immigrant cohort. BACKGROUND: Immigrants in the United States (US) from countries with high per capita rates of gastric cancer remain at higher risk for gastric cancer. The existence of the possibly modifiable risk factor of H. pylori infection and the poor outcomes associated with late-stage disease make screening higher-risk groups with EGD an appealing possibility. It is unknown whether Asian immigrants in the US would accept an EGD-based strategy for gastric cancer screening. STUDY: Cross-sectional study of adult Chinese immigrants in New York City with dyspepsia who underwent EGD in an earlier gastric cancer detection study, who were offered a second EGD four years later. Our main outcome measure was acceptance or refusal of repeat EGD. RESULTS: Seventy-three of the 115 Chinese participants in the earlier study were successfully contacted for this current study. Twenty-three of 73 (32%) underwent repeat EGD. Leading reasons given for declining were lack of symptoms and lack of time. Significantly associated with acceptance of repeat EGD was the belief that EGD will find stomach cancer "nearly always" in someone who has it (P=0.0054; odds ratio=14.0, 2.1 to 94.2 95% confidence interval). CONCLUSIONS: Acceptance of repeat EGD for gastric cancer detection in a cohort of Chinese immigrants was relatively low despite the mitigation of cost and language factors, 2 major barriers to healthcare access. Relocation seemed to be a factor as well. In this population, perceptions of the benefits of EGD may influence acceptance of testing for cancer detection purposes.

Follow-up care after a diagnosis of Helicobacter pylori infection in an Asian immigrant cohort.

GOAL: To study the rate at which Helicobacter pylori infection is treated in an immigrant cohort after diagnosis by esophagogastroduodenoscopy (EGD). BACKGROUND: Gastric cancer is the second leading cause of cancer death worldwide, and is especially prevalent in East Asia; immigrants from this part of the world remain at higher risk. Infection with H. pylori is a known risk factor for gastric cancer. There have been no studies of completion of H. pylori treatment in immigrant populations. STUDY: Prospective cohort study of East Asian immigrants diagnosed with H. pylori infection who underwent EGD in a gastric cancer screening protocol. Our primary outcome was self-report or chart evidence of completion of treatment of H. pylori. RESULTS: Sixty-eight of the 126 participants (54%) tested positive for H. pylori infection on EGD. Forty-nine (72%) were seen for a follow-up visit at one of the clinics involved in the study. According to clinic records, 39 of these 49 participants (57% of all H. pylori-positive participants) were prescribed treatment. Only 31 participants (46%) completed treatment. Of possible explanatory factors, only having a "regular doctor" was significantly associated with treatment completion (odds ratio=5.6; 95% confidence interval, 1.2-25.0). CONCLUSIONS: In a sample of Asian immigrants, the rate of treatment of H. pylori infection, a potentially modifiable risk factor, was lower than expected. Having a "regular doctor" appeared to increase the likelihood of receiving appropriate follow-up care.

Smoking cessation interventions among Chinese Americans: the role of families, physicians, and the media.

This article describes the results from two studies of Chinese Americans. In one study, a convenience sample of patients completed face-to-face interviews to assess smoking patterns in the home, knowledge of tobacco, and ways in which health interventions could be communicated to the community. The other study involved two focus group discussions with the primary purpose of learning how spouses, health care workers, and the media can participate in smoking cessation interventions. A convenience sample of 795 patients at the Charles B. Wang Community Health Center in New York City's Chinatown was interviewed using face-to-face interviews. The focus group discussions were conducted using 15 volunteers. One discussion was conducted in Mandarin and the other in Cantonese. Although 92.7% of the respondents prefer people not smoke in the home, only 21% ban smoking with few exceptions. The focus group participants indicated that often the smoker is the oldest male and he also is the person who establishes the rules. Nearly half of the respondents receive most of their health-related information from their physician, and the focus group participants stated that physicians are highly regarded in their culture. Finally, the majority of respondents receive health-related information from Chinese language media. These results will assist in the planning of a smoking cessation intervention targeting Chinese Americans. The physician represents a key player in any intervention, and public health antismoking messages may be communicated effectively through Chinese language media.

Clinical deterioration in pediatric asthmatic patients after September 11, 2001.

BACKGROUND: New York City residents were exposed to a variety of inhaled substances after the collapse of the World Trade Center. Exposure to these substances might lead to an increase in asthma severity, with residential distance from Ground Zero predictive of the degree of change. OBJECTIVE: We sought to assess the effect of the World Trade Center collapse on local pediatric asthmatic patients. METHODS: We retrospectively reviewed the charts of 205 pediatric patients with established asthma from a clinic in lower Manhattan's Chinatown. Clinical data were obtained for the year before and the year after September 11, 2001. Measurements included numbers of visits, asthma medication prescriptions, oral corticosteroid prescriptions, weekly doses of rescue inhaler, and peak expiratory flow rates. Residential zip codes were used to compare the asthma severity of patients living within and beyond a 5-mile radius of Ground Zero. RESULTS: After September 11, 2001, these children had more asthma-related clinic visits (P = .002) and received more prescriptions for asthma medications (P = .018). No significant differences in oral steroid or rescue inhaler use were noted. Those living within 5 miles had more clinic visits after September 11, 2001 (P = .013); the increase in clinic visits for patients living more than 5 miles from Ground Zero was not significant. Mean percent predicted peak expiratory flow rates decreased solely for those patients living within 5 miles of Ground Zero during the 3 months after September 11, 2001. CONCLUSIONS: Asthma severity worsened after September 11, 2001, in pediatric asthmatic patients living near Ground Zero. Residential proximity to Ground Zero was predictive of the degree of decrease in asthma health.