Suppression of epithelial-mesenchymal transition and apoptotic pathways by miR-294/302 family synergistically blocks let-7-induced silencing of self-renewal in embryonic stem cells.

The embryonic stem cell (ESC)-enriched miR-294/302 family and the somatic cell-enriched let-7 family stabilizes the self-renewing and differentiated cell fates, respectively. The mechanisms underlying these processes remain unknown. Here we show that among many pathways regulated by miR-294/302, the combinatorial suppression of epithelial-mesenchymal transition (EMT) and apoptotic pathways is sufficient in maintaining the self-renewal of ESCs. The silencing of ESC self-renewal by let-7 was accompanied by the upregulation of several EMT regulators and the induction of apoptosis. The ectopic activation of either EMT or apoptotic program is sufficient in silencing ESC self-renewal. However, only combined but not separate suppression of the two programs inhibited the silencing of ESC self-renewal by let-7 and several other differentiation-inducing miRNAs. These findings demonstrate that combined repression of the EMT and apoptotic pathways by miR-294/302 imposes a synergistic barrier to the silencing of ESC self-renewal, supporting a model whereby miRNAs regulate complicated cellular processes through synergistic repression of multiple targets or pathways.

Structural and functional basis for JAK3-deficient severe combined immunodeficiency.

Mutations of the Janus family kinase JAK3 have been found to be responsible for autosomal recessive severe combined immunodeficiency (SCID) in humans. We report here the analysis of four new unrelated patients affected by JAK3-deficient SCID. The genetic defects were heterogeneous and included a large intragenic deletion as well as different point mutations, leading to missense substitutions, early stop codons, or splicing defects. We performed a series of studies of the biochemical events induced by cytokines on lymphoblastoid B-cell lines obtained from these patients. Abnormalities in tyrosine phosphorylation of JAK3 in response to interleukin-2 (IL-2) and IL-4 were present in all patients. Accordingly, IL-2-mediated phosphorylation of STAT5 was also absent or barely detectable. On the contrary, in all cases, we could show reduced but clear phosphorylation of STAT6 upon IL-4 stimulation. In one patient carrying a single amino acid change (Glu481Gly) in the JH3 domain of JAK3, we observed partially conserved IL-2 responses resulting in reduced but detectable levels of JAK3 and STAT5 phosphorylation. Interestingly, the patient bearing this mutation developed a substantial number of circulating CD4(+)/CD45RO+ activated T lymphocytes that were functionally impaired. In two cases, patients' cells expressed JAK3 proteins with mutations in the JH2 pseudo-kinase domain. A single cysteine to arginine substitution (Cys759Arg) in this region resulted in high basal levels of constitutive JAK3 tyrosine phosphorylation unresponsive to either downregulation by serum starvation or cytokine-mediated upregulation. The characterization of the genetic defects and biochemical abnormalities in these JAK3-deficient patients will help define the role of JAK3 in the ontogeny of a competent immune system and may lead to a better understanding of the JAK3 functional domains.

Developing indicators for the Medicare Quality Indicator System (MQIS): challenges and lessons learned.

BACKGROUND: The Medicare Quality Indicator System (MQIS), initiated in 1993, was intended to form the basis for the Health Care Financing Administration's (HCFA's; Washington, DC) hospital-based quality measurement system. The MEDSTAT Group (Washington, DC) established quality indicator development methods for five clinical conditions, including early-stage breast cancer, diabetes mellitus, and upper gastrointestinal and lower intestinal bleeding. DEVELOPMENT OF QUALITY INDICATORS: Five national expert panels were convened to identify scientifically based hospital processes of care related to positive patient outcomes, as described in research studies and/or broadly accepted by the medical and allied health professions as indicators of high-quality care. LESSONS AND CHALLENGES: One of the most important lessons learned was the need for a narrow clinical focus for each quality indicator module. If the focus was adequately narrowed, all other tasks could be accomplished more efficiently and less ambiguously. Also, selection of the expert panel chair should occur early because of the chair's pivotal contributions to the clinical focus selection, literature review, and development of draft quality indicators. Perhaps the most starting finding and biggest challenge was the paucity of scientifically sound literature to support the clinical topics; except for the breast cancer studies, most of the available literature was categorized as flawed to some degree. A critical challenge for development of quality indicators is to translate what has been learned from the best scientific efficacy studies into indicators of effective rather than efficacious care. CONCLUSIONS: In choosing quality indicators, disease incidence and potential for quality improvement are important parameters. Although the former is relatively easy to define, the latter is not.

Interleukin-4 signaling in B lymphocytes from patients with X-linked severe combined immunodeficiency.

Interleukin-4 (IL-4) is an important cytokine for B and T lymphocyte function and mediates its effects via a receptor that contains gammac. B cells derived from patients with X-linked severe combined immunodeficiency (X-SCID) are deficient in gammac and provide a useful model in which to dissect the role of this subunit in IL-4-mediated signaling. We found that although IL-4 stimulation of X-SCID B cells did not result in Janus tyrosine kinase-3 (JAK3) phosphorylation, other IL-4 substrates including JAK1 and IRS-1 were phosphorylated. Additionally, we detected signal transducers and activators of transcription 6 (STAT6) tyrosine phosphorylation and DNA binding activity in X-SCID B cells with a wide range of gammac mutations. However, reconstitution of these X-SCID B cells with gammac enhanced IL-4-mediated responses including STAT6 phosphorylation and DNA binding activity and resulted in increased CD23 expression. Thus, gammac is not necessary to trigger IL-4-mediated responses in B cells, but its presence is important for optimal IL-4-signaling. These results suggest that two distinct IL-4 signaling pathways exist.

Signaling via IL-2 and IL-4 in JAK3-deficient severe combined immunodeficiency lymphocytes: JAK3-dependent and independent pathways.

Both IL-2 and IL-4 bind to receptors containing the common gamma chain and JAK3. Although JAK3 is required for proper lymphoid development, the precise roles of this kinase in IL-2 and IL-4 signaling in lymphocytes have not been defined. Here, we have studied IL-2 and IL-4 signaling in B cell lines lacking JAK3. Although IL-2-induced phosphorylation of IL-2R beta, JAK1, and STAT5 all required the presence of JAK3, IL-4-mediated phosphorylation of JAK1, STAT6, and insulin receptor substrates 1 and 2 did not. However, IL-4-induced effects were clearly improved following JAK3 expression. These data indicate that IL-4 signaling occurs in the absence of of JAK3, but is comparatively inefficient. These findings may help in understanding the pathogenesis of the immunodeficiency that occurs with mutations of JAK3 and may suggest a mechanism for the pleiotropic effects of IL-4.

In vitro correction of JAK3-deficient severe combined immunodeficiency by retroviral-mediated gene transduction.

Mutations affecting the expression of the Janus family kinase JAK3 were recently shown to be responsible for autosomal recessive severe combined immunodeficiency (SCID). JAK3-deficient patients present with a clinical phenotype virtually indistinguishable from boys affected by X-linked SCID, a disease caused by genetic defects of the common gamma chain (gamma c) that is a shared component of the receptors for IL-2, IL-4, IL-7, IL-9, and IL-15. The specific interaction of JAK3 and gamma c represents the biochemical basis for the similarities between these two immunodeficiencies. Both forms of SCID are characterized by recurrent, severe infections leading to death in infancy unless successfully treated by allogeneic bone marrow transplantation. Because of the potentially lethal complications associated with allogeneic bone marrow transplantation and the frequent lack of suitable marrow donors, the development of alternative forms of therapy is highly desirable. To this end, we investigated a retroviral-mediated gene correction approach for JAK3-deficiency. A vector carrying a copy of JAK3 cDNA was constructed and used to transduce B cell lines derived from patients with JAK3-deficient SCID. We demonstrate restoration of JAK3 expression and phosphorylation upon IL-2 and IL-4 stimulation. Furthermore, patients' cells transduced with JAK3 acquired the ability to proliferate normally in response to IL-2. These data indicate that the biological defects of JAK3-deficient cells can be efficiently corrected in vitro by retroviral-mediated gene transfer, thus providing the basis for future investigation of gene therapy as treatment for JAK3-deficient SCID.

Mammography use in older women with regular physicians: what are the predictors?

Results of a longitudinal study of 1,050 women 65 years of age and older under the care of faculty internists demonstrate that individual and sociodemographic factors predict mammography use. The majority of the sample (79%) had received a mammogram within the past two years. Multiple logistic regression analyses of findings from a telephone survey showed that mammographic screening was significantly higher among women who had recently received a Pap smear, whose annual household incomes exceeded $30,000, and whose personal health care habits were preventively oriented; they used more preventive services such as routine dental care and engaged in more preventive behaviors such as seat-belt use and routine exercise. Mammography use was significantly higher among those 75 or younger. These findings suggest that enhancing patient preventive orientations should be part of interventions designed to increase screening. Medical Subject Headings (MeSH): appropriateness review, preventive health services, utilization, aged, Medicare.

Interleukins 2, 4, 7, and 15 stimulate tyrosine phosphorylation of insulin receptor substrates 1 and 2 in T cells. Potential role of JAK kinases.

The signaling molecules insulin receptor substrate (IRS)-1 and the newly described IRS-2 (4PS) molecule are major insulin and interleukin 4 (IL-4)-dependent phosphoproteins. We report here that IL-2, IL-7, and IL-15, as well as IL-4, rapidly stimulate the tyrosine phosphorylation of IRS-1 and IRS-2 in human peripheral blood T cells, NK cells, and in lymphoid cell lines. In addition, we show that the Janus kinases, JAK1 and JAK3, associate with IRS-1 and IRS-2 in T cells. Coexpression studies demonstrate that these kinases can tyrosine-phosphorylate IRS-2, suggesting a possible mechanism by which cytokine receptors may induce the tyrosine phosphorylation of IRS-1 and IRS-2. We further demonstrate that the p85 subunit of phosphoinositol 3-kinase associates with IRS-1 in response to IL-2 and IL-4 in T cells. Therefore, these data indicate that IRS-1 and IRS-2 may have important roles in T lymphocyte activation not only in response to IL-4, but also in response to IL-2, IL-7, and IL-15.

Health promotion and disease prevention for older adults: opportunity for change or preaching to the converted?

Health promotion and disease prevention for the elderly offer the potential for improving the quality of life for the growing population of older adults, while reducing the economic burden on the health system. Whether this potential can be realized depends, in part, on whether those older adults whose health behaviors put them at risk actually use preventive services when offered the opportunity. In 1988 the Health Care Financing Administration began a series of health promotion demonstrations to address health issues related to older adults. This article reports on program participation at one of the five demonstration sites. Over 1,900 community-dwelling Medicare beneficiaries who receive their health care through fee-for-service providers were enrolled in the demonstration. These enrollees were randomly assigned to control and experimental groups, with the latter offered health screening and promotion services. Nine hundred-seventy-three of the experimental subjects and 938 of the control subjects completed a lengthy telephone interview, which determined each person's use of preventive services and practices. Although all 973 experimental subjects were invited by letter and follow-up telephone calls to attend these free-of-charge, Medicare-provided sessions, not everyone attended. We analyzed 17 health behaviors of those who attended the first session and those who did not. Those engaging in these preventive behaviors were neither more nor less likely to attend the screening services. Thus, we found neither "favorable" nor "unfavorable" selection bias in the use of these preventive services.

Benzodiazepine use in older, community-dwelling southern Californians: prevalence and clinical correlates.

OBJECTIVE: To determine the use of benzodiazepines (BZDs) in an older, community-dwelling sample and to examine the sociodemographic and clinical correlates of BZD use. DESIGN: A cross-sectional study of 1752 elderly people (aged > or = 65 y) who completed a mailed medication survey and a telephone health status survey. PARTICIPANTS: Participants were invited to participate in a large Medicare demonstration project on prevention by their private physicians, who were also enrolled in the larger study. Participants had to be English-speaking, could not have dementia or a terminal illness, and had to give informed consent to participate in the study. MAIN OUTCOME MEASURES: Sociodemographic and health status variables that predicted BZD use were examined. Sociodemographic variables included age, gender, ethnicity, education, and income. Health status variables included functional status, with measures of mental, social, and physical health. Influenza immunization status was used as an indicator for preventive health services use and self-reported chronic illness was used as a measure of comorbidity. RESULTS: Twenty percent of the participants used BZDs at least twice in the past year. We found that those who used BZDs were more than twice as likely to take ten or more drugs, two-and-a-half times more likely to have difficulty falling asleep, and over twice as likely to be depressed. BZD users were also more likely to be white, to have a college education, and to have received a recent influenza shot, but were not more likely to be women when controlled for health status. CONCLUSIONS: Further clinical research should explore the relationship between BZD use among older patients and the BZD-associated adverse clinical factors we observed, as well as the association between multiple drug use and potential adverse outcomes in older BZD users.

Comparison of oral health ratings by dentists and dentate elders.

Previous studies suggest a discrepancy between the way dentists and patients measure oral health. The purpose of this study was to determine the relationship between a dentist's rating of an older dentate person's oral health and the patient self-rating using a single-item indicator, and to compare the clinical (i.e., number of teeth, caries, etc.) and subjective (problems with function, pain, etc.) factors that influence the rating. The study sample consisted of 776 older dentate people. Results showed that dentists judged subjects' oral health significantly more positively than the self-ratings. Approximately 30 percent of the elders rated their oral health identically to the dentist and half rated their oral health lower than the dentist. Bivariate comparisons showed that similar clinical and subjective variables were associated with the dentist and patient ratings. Multiple regression findings, however, highlighted differences in the factors that influenced the ratings. In addition, the proportion of variance accounted for by the clinical factors as opposed to the subjective factors was greater for the dentist rating (R2 = .28 of .33) than the subject self-rating (R2 = .18 of .43).

The relationship between dental utilization and preventive participation among a well-elderly sample.

Previous studies have shown that dental utilization by older people is lower than for the general population. This study hypothesizes that an elder's tendency toward participating in preventive health activities may be an important factor in explaining the likelihood of accessing the dentist. Subjects included 1,911 older individuals who enrolled in the UCLA Medicare Screening and Health Promotion Trial. All were interviewed about their utilization of preventive health services and participation in preventive behaviors. A recent dental visit was positively associated with all sociodemographic variables examined except age and sex. It was also related to health status questions and utilization of the preventive health services and health behaviors studied. Logistic regression analysis showed that both summary preventive health behavior and preventive service utilization variables were important factors in explaining a recent dental visit (model chi-square = 221.4, P = .001) along with income, not having a removable prosthesis, and perceiving the need for dental care. This study showed that dental utilization is related to older people's participation in other preventive activities. When in contact with older people, health care professionals should consider current oral and general preventive health status and encourage appropriate referral for preventive activities.

Patient-related predictors of rehabilitation use for community-dwelling older Americans.

OBJECTIVE: To determine patient factors that predict use of physical or occupational therapy (PT/OT) services by elderly people. DESIGN: Time-series study of the relationship of PT/OT use to a variety of characteristics present at baseline. PARTICIPANTS: Eight-hundred nine community-dwelling men and women aged 65 and older. SETTING: The Medicare Screening and Health Promotion Trial at UCLA. MAIN OUTCOME MEASURES: Use of PT/OT services, as reported in a telephone survey 1 year after initial information was obtained on the same subjects by the baseline telephonic survey. RESULTS: Fifteen percent of the sample used PT/OT within 12 months of baseline. In multiple logistic regression analysis, PT/OT use was significantly less frequent among racial minorities, less well educated groups, and the oldest age group. PT/OT use was higher among those who had both functional disability and the presence of arthritis, heart or lung disease, or a prior history of stroke. However, neither functional disability alone nor the presence of arthritis, cardiovascular or lung disease, in the absence of limited functioning, was associated with PT/OT use. Patients who had obtained a pneumococcal vaccination or used transportation services were also more likely to receive PT/OT. CONCLUSIONS: Our findings suggest that there may be important sociodemographic inequalities in the use of rehabilitation services and raise the possibility of inappropriate underuse in certain subgroups. Additional studies are needed to determine whether similar inequalities of PT/OT use are found in other populations and whether rehabilitation is effective in various subgroups.

Predictors of mortality in older patients following medical intensive care: the importance of functional status.

OBJECTIVE: We examined predictors of hospital and 6-month mortality in older Medical Intensive Care Unit (MICU) patients with particular attention to age and functional status. Age is generally thought to be strongly associated with intensive care outcomes, but this relationship may be confounded by age-related changes. These age-related changes may be approximated by changes in functional status (FS). DESIGN: We conducted a retrospective chart review and collected severity of illness data using the Acute Physiology Score (APS), pre-hospitalization FS dichotomized as limited or not limited, and hospital mortality. County death records were reviewed for 6-month mortality. SETTING: Three community hospital MICUs. PATIENTS: Four-hundred MICU patients aged 50 and older admitted during the study period. RESULTS: Limited FS was found in 42% of the 227 patients who had FS data in the chart. Mortality was significantly associated with APS, age, FS, immunocompromise state, comorbidity, and nursing home residence. In logistic regression analyses, while controlling for important variables, APS (P less than 0.001) and age greater than or equal to 75 with limited FS (P less than 0.05) were associated with hospital mortality. Six-month mortality predictors were APS (P less than 0.001), hospital (P less than 0.05), immunocompromised state (P less than 0.05) and age greater than or equal to 75 with limited FS (P less than 0.05). CONCLUSIONS: We found that among patients without functional limitations, the oldest group was no more likely to die than the youngest group. Age and functional status had a significant interaction: patients older than 75 years with functional limitations were almost six times more likely to die in hospital compared to the reference group of patients between 50-64 years old without functional limitations. We conclude that functional status is an important predictor of outcome in older MICU patients.

Differences in health status between older and younger homeless adults.

The Institute of Medicine has placed a priority on determining the special health-care needs of elderly homeless persons. As part of a community-based study of 521 homeless adults in two beach communities of Los Angeles, we compared the demographic characteristics and health of older (age rangek 50-78, n = 61) and younger (age range, 18-49, n = 460) homeless individuals. Compared with younger adults, older adults were more likely to be white (85% versus 61%), veterans (59% versus 27%), retired (36% versus 3%), and living in a vehicle (21% versus 8%). Older adults were more likely to report having a chronic disease (69% versus 49%), functional disabilities, no informal social contacts during the previous month (49% versus 27%), observed high blood pressure (42% versus 22%), elevated creatinine (11% versus 2%), and elevated cholesterol (57% versus 36%). Older adults were less likely to have a toothache (3% versus 30%), report psychotic symptoms (25% versus 42%), and to be illegal drug users (15% versus 55%). Although they are chronologically younger, the constellation of health and functional problems of older homeless adults resemble those of geriatric persons in the general population. We suggest that geriatricians could play a significant role in training other primary-care providers to evaluate and treat socially isolated older homeless adults in a more comprehensive way than is currently standard in practice (e.g., interdisciplinary team care and emphasis on functional status, rehabilitative medicine, and assessment for sensory impairment).

The early effect of Medicare's prospective payment system on the use of medical intensive care services in three community hospitals.

To assess the impact of Medicare's prospective payment system (PPS) on patient care and outcome from the medical intensive care unit (MICU), we reviewed the medical records of 400 MICU patients from three community hospitals: 200 patients were admitted before the PPS and 200 were admitted after the PPS. We sampled Medicare patients, aged 65 years and over, and non-Medicare comparison patients, aged 50 to 64 years, collecting data on case mix, treatment intensity and discharge disposition, hospital and six-month mortality, length of stay, and number of intensive care unit beds. After the PPS, the number of intensive care unit beds decreased 31%, without changes in MICU patients' illness severity or treatment intensity. Hospital length of stay decreased 15% in the Medicare group and 43% in the comparison group. For both Medicare and comparison patients combined, MICU length of stay decreased 14% and patients after the PPS were less likely to be discharged to go home. There were no significant changes in in-hospital or six-month mortality. Thus, clinically meaningful decreases in length of stay among seriously ill patients did not result in a change in in-hospital or six-month mortality.