Disparate views of community in primary health care: understanding how perceptions influence success

The importance of community in primary health care (PHC) is evident in the role of community participation and in the types of programs that are routinely implemented (community health-worker [CHW] programs, community clinics, community-based disease-control programs). Few health care providers and program administrators, however, have considered the meaning of community. Instead, they frequently impose their own definition of community and assume that it corresponds to local realities. This is problematic because target populations may have different ideas about what a community is and how it functions. When disparate ideas of community exist, they can affect the implementation of PHC programs, leading to low rates of acceptance, participation, and utilization. Using two examples, a community clinic in El Alto, Bolivia, and a CHW program in Rio Branco, Brazil, this article discusses some of the problems that arise when local definitions of community do not correspond to programmatic definitions.     

PATH: a task for the inference of phylogenies

Phylogenetic Analysis Task in Husar (PATH) is a task for the inference of phylogenies. It executes three phylogenetic methods and automatically chooses the evolutionary model for each set of data. The output of the tasks shows the consensus trees together with full results obtained from all executed methods. AVAILABILITY: PATH is available at the German EMBnet node after registration via www at http://genome.dkfz-heidelberg.de     

Phosphoinositide binding inhibits alpha-actinin bundling activity

alpha-Actinin is an abundant actin-bundling and adhesion protein that directly links actin filaments to integrin receptors. Previously, in platelet-derived growth factor-treated fibroblasts, we demonstrated that phosphoinositides bind to alpha-actinin, regulating its localization (Greenwood, J. A., Theibert, A. B., Prestwich, G. D., and Murphy-Ullrich, J. E. (2000) J. Cell Biol. 150, 627- 642). In this study, phosphoinositide binding and regulation of alpha-actinin function is further characterized. Phosphoinositide binding specificity, determined using a protein-lipid overlay procedure, suggests that alpha-actinin interacts with phosphates on the 4th and 5th position of the inositol head group. Binding assays and mutational analyses demonstrate that phosphoinositides bind to the calponin homology domain 2 of alpha-actinin. Phosphoinositide binding inhibited the bundling activity of alpha-actinin by blocking the interaction of the actin-binding domain with actin filaments. Consistent with these results, excessive bundling of actin filaments was observed in fibroblasts expressing an alpha-actinin mutant with decreased phosphoinositide affinity. We conclude that the interaction of alpha-actinin with phosphoinositides regulates actin stress fibers in the cell by controlling the extent to which microfilaments are bundled.     

The periodontal pathogen Porphyromonas gingivalis harnesses the chemistry of the mu-oxo bishaem of iron protoporphyrin IX to protect against hydrogen peroxide

The major haem component in the black pigment of Porphyromonas gingivalis is the mu-oxo bishaem of iron protoporphyrin IX and formation and cell-surface binding of this haem species is proposed as an extracellular buffer against reactive oxidants [Smalley, J.W. et al. (1998) Biochem. J. 331, 681-685]. P. gingivalis cells grown in the presence of the mu-oxo bishaem were protected against H(2)O(2) compared to control cells grown without it. When added to the growth medium, soluble mu-oxo bishaem inactivated H(2)O(2) and supported cell growth. Cells carrying a surface layer of mu-oxo bishaem were less susceptible to peroxidation by H(2)O(2). Cell-surface haems were slowly destroyed during reaction with H(2)O(2). Binding of mu-oxo bishaem by P. gingivalis may aid survival during neutrophil attack through inactivation of hydrogen peroxide.     

Time course of vasodilation at the onset of repetitive skeletal muscle contractions

To characterize the vasodilatory response in the transition from a single skeletal contraction to a series of contractions, we measured the response of hamster cremaster muscle arterioles associated with four to five skeletal muscle fibers stimulated to contract for one, two, three, or four contractions (250-ms train duration) at 4-s intervals [15 contractions per minute (CPM)] for up to 12 s, at stimulus frequencies of 4, 10, 20, 30, 40, 60, and 80 Hz. To investigate the contribution of contraction frequency, we stimulated muscle fiber bundles at 30 or 60 CPM for 12 s at stimulus frequencies of 4, 20, and 60 Hz. Arteriolar diameters at the site of overlap with the stimulated muscle fibers were measured before and after each contraction. At 15 CPM at 4, 20, and 60 Hz, we observed a peak change in diameter following the first contraction of 1.1 +/- 0.1, 1.6 +/- 0.2, and 2.1 +/- 0.2 mum that almost doubled in response to the second contraction (2.0 +/- 0.1, 3.0 +/- 0.1, and 3.8 +/- 0.1 mum, respectively), but there was no further dilation following the third or fourth contraction. A similar response occurred at all stimulus and contraction frequencies tested. At 30 and 60 CPM at 60 Hz, the plateau after two contractions was followed by a further increase in diameter to a second plateau at 7-8 s. Therefore, the vasodilatory response in the transition from single to multiple contractions had components that were stimulation parameter dependent and independent and showed a plateauing behavior indicative of rapid changes in either the nature and/or concentration of vasodilators released or changes in vascular reactivity.     

Oxidative Inhibition of Protein Phosphatase 2A Activity: Role of Catalytic Subunit Disulfides

A molecular basis for the inhibition of brain protein phosphatase 2A (PP2A) activity by oxidative stress was examined in a high-speed supernatant (HSS) fraction from rat cerebral cortex. PP2A activity was subject to substantial disulfide reducing agent-reversible inhibition in the HSS fraction. Results of gel electrophoresis support the conclusions that inhibition of PP2A activity was associated with the both the disulfide cross-linking of the catalytic subunit (PP2A_C) of the enzyme to other brain proteins and with the formation of an apparent novel intramolecular disulfide bond in PP2A_C. Additional findings that the vicinal dithiol cross-linking reagent phenylarsine oxide (PAO) produced a potent dithiothreitol-reversible inhibition of PP2A activity suggest that the cross-linking of PP2A_C vicinal thiols to form an intramolecular disulfide bond may be sufficient to inhibit PP2A activity under oxidative stress. We propose that the dithiol–disulfide equilibrium of a vicinal thiol pair of PP2A_C may confer redox sensitivity on cellular PP2A.     

Creative teaching assistant organization to maintain an Integrative Physiology course with 440 students

We were recently challenged with trying to maintain the integrity and learning experience of our Physiology course, which included the use of long-answer, essay-style test questions, with a class size that increased over 2 yr by approximately 200 students. We reorganized the teaching assistant (TA) support structure in an attempt to keep the testing style and mark (or grade) the exams accurately, in a timely fashion, and provide feedback to the students that want it. Each of four TAs became experts in two sections of the course. To assess our success, TA time allocation for specific duties was recorded. Marking (or grading) accuracy was assessed by recording test data including the number of tests returned for remarking and how much marks changed by when a grade was reassessed. Student feedback was solicited to determine whether this structure provided adequate feedback and support to the students. TAs spent an average of 115 h and 35 min +/- 7 h 21 min of a total of 140 h contracted. On average, 13.2 +/- 0.5% of the tests were identified as being inaccurately graded by 4.2 +/- 0.7%. When asked to score whether the statement of assessment of students was fair, it scored 4.5 out of 5, where 5 equals strongly agree. When asked whether the course provided a worthwhile learning experience, the question scored 4.84 out of 5. Thus, we were successful at marking the exams accurately, in a timely fashion, and providing the necessary feedback, and we were successful at maintaining the objectives of the Physiology course with a class size of 440 students.     

Assessment of community support for Wolbachia-mediated population suppression as a control method for Aedes aegypti mosquitoes in a community cohort in Puerto Rico

Arboviral diseases transmitted by Aedes species mosquitoes pose an increasing public health challenge in tropical regions. Wolbachia-mediated population suppression (Wolbachia suppression) is a vector control method used to reduce Aedes mosquito populations by introducing male mosquitoes infected with Wolbachia, a naturally occurring endosymbiotic bacterium. When Wolbachia-infected male mosquitoes mate with female wild mosquitoes, the resulting eggs will not hatch. Public support is vital to the successful implementation and sustainability of vector control interventions. Communities Organized to Prevent Arboviruses (COPA) is a cohort study to determine the incidence of arboviral disease in Ponce, Puerto Rico and evaluate vector control methods. Focus groups were conducted with residents of COPA communities to gather their opinion on vector control methods; during 2018–2019, adult COPA participants were interviewed regarding their views on Wolbachia suppression; and a follow-up questionnaire was conducted among a subset of participants and non-participants residing in COPA communities. We analyzed factors associated with support for this method. Among 1,528 participants in the baseline survey, median age was 37 years and 63% were female. A total of 1,032 (68%) respondents supported Wolbachia suppression. Respondents with an income of $40,000 or more were 1.34 times as likely [95% CI: 1.03, 1.37] to support Wolbachia suppression than those who earned less than $40,000 annually. Respondents who reported repellant use were 1.19 times as likely to support Wolbachia suppression [95% CI: 1.03, 1.37]. A follow-up survey in 2020 showed that most COPA participants (86%) and non-participants living in COPA communities (84%) supported Wolbachia suppression during and after an educational campaign. The most frequent questions regarding this method were related to its impact on human and animal health, and the environment. Continuous community engagement and education efforts before and during the implementation of novel vector control interventions are necessary to increase and maintain community support.