Regulation of the resident chromosomal copy of c-myc by c-Myb is involved in myeloid leukemogenesis

c-myb is a frequent target of retroviral insertional mutagenesis in murine leukemia virus-induced myeloid leukemia. Induction of the leukemogenic phenotype is generally associated with inappropriate expression of this transcriptional regulator. Despite intensive investigations, the target genes of c-myb that are specifically involved in development of these myeloid lineage neoplasms are still unknown. In vitro assays have indicated that c-myc may be a target gene of c-Myb; however, regulation of the resident chromosomal gene has not yet been demonstrated. To address this question further, we analyzed the expression of c-myc in a myeloblastic cell line, M1, expressing a conditionally active c-Myb-estrogen receptor fusion protein (MybER). Activation of MybER both prevented the growth arrest induced by interleukin-6 (IL-6) and rapidly restored c-myc expression in nearly terminal differentiated cells that had been exposed to IL-6 for 3 days. Restoration occurred in the presence of a protein synthesis inhibitor but not after a transcriptional block, indicating that c-myc is a direct, transcriptionally regulated target of c-Myb. c-myc is a major target that transduces Myb's proliferative signal, as shown by the ability of a c-Myc-estrogen receptor fusion protein alone to also reverse growth arrest in this system. To investigate the possibility that this regulatory connection contributes to Myb's oncogenicity, we expressed a dominant negative Myb in the myeloid leukemic cell line RI-4-11. In this cell line, c-myb is activated by insertional mutagenesis and cannot be effectively down regulated by cytokine. Myb's ability to regulate c-myc's expression was also demonstrated in these cells, showing a mechanism through which the proto-oncogene c-myb can exert its oncogenic potential in myeloid lineage hematopoietic cells.

The p24 family member p23 is required for early embryonic development

The p24 family of type I integral-membrane proteins, which are localised in the endoplasmic reticulum (ER), the intermediate compartment and the Golgi apparatus, are thought to function as receptors for cargo exit from the ER and in transport vesicle formation. Members of the p24 family have been found in a molecular complex and are enriched in COPI-coated vesicles, which are involved in membrane traffic between the ER and Golgi complex. Although expressed abundantly, simultaneous deletion of several family members does not appear to affect cell viability and protein secretion in yeast. In order to gain more insights into the physiological roles of different p24 proteins, we generated mice deficient in the expression of one family member, p23 (also called 24delta1, see for alternative nomenclature). In contrast to yeast genetics, in mice disruption of both p23 alleles resulted in early embryonic lethality. Inactivation of one allele led not only to reduced levels of p23 itself but also to reduced levels of other family members. The reduction in steady-state protein levels also induced structural changes in the Golgi apparatus, such as the formation of dilated saccules. The generation of mice deficient in p23 expression has revealed an essential and non-redundant role for p23 in the earliest stages of mammalian development. It has also provided genetic evidence for the participation of p24 family members in oligomeric complexes and indicates a structural role for these proteins in maintaining the integrity of the early secretory pathway.

Intractable nausea, vomiting and diarrhea in a Mexican woman with No recent travel history

A 45-year-old Mexican woman with a history of noninsulin dependent diabetes mellitus (NIDDM), hypertension, and coronary artery disease presented to the hospital after 2 months of intractable nausea, vomiting and diarrhea-all made worse by eating and drinking. She reported fever, chills, anorexia and a documented 50-pound weight loss during this period. She denied the signs and symptoms of melena, hematochezia, steatorrhea or constipation. She also reported left leg pain and decreased sensation and strength of her left leg compared to the right leg. She had been hospitalized 2 weeks prior to admission with the same symptoms and a diagnosis of viral gastroenteritis. She was also treated for H. pylori, but subsequent biopsy results were negative by Steiner stain.

Risk factors for hepatitis C transmission in the Victorian population: a telephone survey

OBJECTIVE

To measure knowledge and prevalences of risk factors for hepatitis C infection in the Victorian community.

METHOD

Telephone survey of 757 Victorian householders aged 15+ years, March 1996.

RESULTS

An estimated 2.2% of Victorians have injected illicit drugs; 4.8% have tattoos and 49.6% have skin piercings; 11.4% received a blood transfusion before screening for HCV was introduced; 10.9% have had a test for HCV antibody. A majority of respondents perceived sexual contact and receipt of a transfusion to be risks for HCV transmission.

CONCLUSIONS

Risk factors associated with the spread of HCV are widespread in the Victorian community; however, the most important risk factor--injecting drug use--has low prevalence. Considerable uncertainty exists about risk factors for hepatitis C.

IMPLICATIONS

A very small percentage of Victorians are injecting drug users and therefore at highest risk of hepatitis C infection, therefore transmission control programs can be efficiently focused on this group. The Victorian community needs to be better educated about risk factors for hepatitis C, in particular that transfusions and blood donations are safe.

Diabetes management in a health maintenance organization. Efficacy of care management using cluster visits

OBJECTIVE

To evaluate the effectiveness of a cluster visit model led by a diabetes nurse educator for delivering outpatient care management to adult patients with poorly controlled diabetes.

RESEARCH DESIGN AND METHODS

This study involved a randomized controlled trial among patients of Kaiser Permanente's Pleasanton, CA, center who were aged 16-75 years and had either poor glycemic control (HbA1c > 8.5%) or no HbA1c test performed during the previous year. Intervention subjects received multidisciplinary outpatient diabetes care management delivered by a diabetes nurse educator, a psychologist, a nutritionist, and a pharmacist in cluster visit settings of 10-18 patients/month for 6 months. Outcomes included change (from baseline) in HbA1c levels; self-reported changes in self-care practices, self-efficacy, and satisfaction; and utilization of inpatient and outpatient health care.

RESULTS

After the intervention, HbA1c levels declined by 1.3% in the intervention subjects versus 0.2% in the control subjects (P < 0.0001). Several self-care practices and several measures of self-efficacy improved significantly in the intervention group. Satisfaction with the program was high. Both hospital (P = 0.04) and outpatient (P < 0.01) utilization were significantly lower for intervention subjects after the program.

CONCLUSIONS

A 6-month cluster visit group model of care for adults with diabetes improved glycemic control, self-efficacy, and patient satisfaction and resulted in a reduction in health care utilization after the program.

Bullous mastocytosis: a fatal outcome

A 6-week-old boy was referred with a generalized bullous rash since birth. Examination revealed bullous mastocytosis with initially no evidence of systemic involvement. Hepatosplenomegaly was noted at 6 months, and at 12 months he was found to have generalized lymphadenopathy. He developed bouts of vomiting associated with increased blistering. At 17 months he had sudden collapse following a brief bout of vomiting and was apneic and asystolic on arrival at the emergency department. The cause of death was attributed to massive hypotension secondary to mast cell degranulation. Although childhood mastocytosis has a favorable course in general, the subset of children with congenital bullous mastocytosis is at higher risk of sudden death and a more guarded prognosis should be given.

Age-related left ventricular function in the mouse: analysis based on in vivo pressure-volume relationships

Our study compared left ventricular (LV) function between senescent and young adult mice through in situ pressure-volume loop analysis. Two groups of mice (n = 9 each), 6-mo-old and 16-mo-old (senescent) mice, were anesthetized with urethan and alpha-chloralose, and their LV were instrumented with a Millar 1.4-Fr conductance micromanometer catheter for the acquisition of the pressure-volume loops. The senescent mice had a significantly decreased contractile function related to load-dependent parameters, including stroke volume index, ejection fraction, cardiac output index, stroke work index, and maximum derivative of change in systolic pressure over time. The load-independent parameters, preload recruitable stroke work and the slope (end-systolic volume elastance) of the end-systolic pressure-volume relationship, were significantly decreased in the senescent mice. Heart rate and arterial elastance were not different between the two groups; however, the ventricular-to-vascular coupling ratio (ratio of elastance of artery to end-systolic volume elastance) was increased by threefold in the senescent mice (P < 0. 001). Thus there were significant decreases in contractile function in the senescent mouse heart that appeared to be related to reduced mechanical efficiency but not related to arterial elastance.

A longitudinal study into the perceptions of caring among student nurses using multivariate analysis of the Caring Dimensions Inventory

A longitudinal study involving student nurses' responses to the Caring Dimensions Inventory (CDI) was carried out to investigate the development of perceptions of caring. This study continues previously reported work in which the development of the CDI was described. The current study was designed to see if the CDI could detect changes in perceptions of caring among student nurses as they progressed through their training. Data were collected on the same subjects at three points, each a year apart, throughout the study. A cohort of 168 student nurses entering training was recruited into the present study and data from the CDI was analysed using exploratory factor analysis. A four factor structure for perceptions of caring throughout the study was supported, with some evidence for a five factor structure at 24 months into the programme of nurse education. A professional and technical factor increased in congruence with a similar factor, identified in a previous study, throughout the present study and was used to provide factor scores for individual students. There was a statistically significant and moderately sized correlation between the score on this factor and the age of the student nurses. The five factor solution yielded a factor of accountability. Professional and educational consequences of the study are discussed along with the problem of attrition in longitudinal studies.