Induction of acrosomal exocytosis in chicken spermatozoa by inner perivitelline-derived N-linked glycans

In birds, the ovum is surrounded by a glycoprotein coat known as the inner perivitelline layer (IPVL), which is analogous to the mammalian zona pellucida and, as such, is the site of initial sperm binding and induction of acrosomal exocytosis (the acrosome reaction). In this study, we demonstrate that oligosaccharides isolated from chicken-IPVL glycoproteins are capable of inducing the acrosome reaction in chicken spermatozoa. Preparations containing only O-linked glycans were unable to induce the acrosome reaction whereas N-linked oligosaccharides released from the IPVL by PNGaseF treatment could induce the acrosome reaction. Addition of galactose to terminal N-acetyglucosamine residues suppressed the acrosome reaction-inducing capacity of the oligosaccharide preparation; however, this capacity could be restored by co-incubation with beta-galactosidase. This evidence suggests that the acrosome reaction-inducing factor is probably an N-linked oligosaccharide with terminal N-acetyl-glucosamine residues.

Regulation of STAT3 by direct binding to the Rac1 GTPase

The signal transducers and activators of transcription (STAT) transcription factors become phosphorylated on tyrosine and translocate to the nucleus after stimulation of cells with growth factors or cytokines. We show that the Rac1 guanosine triphosphatase can bind to and regulate STAT3 activity. Dominant negative Rac1 inhibited STAT3 activation by growth factors, whereas activated Rac1 stimulated STAT3 phosphorylation on both tyrosine and serine residues. Moreover, activated Rac1 formed a complex with STAT3 in mammalian cells. Yeast two-hybrid analysis indicated that STAT3 binds directly to active but not inactive Rac1 and that the interaction occurs via the effector domain. Rac1 may serve as an alternate mechanism for targeting STAT3 to tyrosine kinase signaling complexes.

Improved RNA extraction and one-tube RT-PCR assay for simultaneous detection of control plant RNA plus several viruses in plant extracts

A procedure was developed for simultaneous detection of plant RNA viruses and of plant RNA, as a control. RT-PCR amplification with primers designed for the detection of the plant mRNAs encoding malate dehydrogenase (MDH) and the large subunit of ribulose bisphosphate carboxylase oxygenase (RubiscoL) was used for the development of a plant extraction procedure that consistently yields extracts that can be amplified. The control amplification was used successfully on extracts from cane, leaf and/or bud tissues from grapevine, apple, raspberry, strawberry, peach, apricot, plum and wheat. Multiplex RT-PCR conditions were established for the simultaneous detection in grapevine extracts of either arabis mosaic virus, rupestris stem pitting associated virus and malate dehydrogenase mRNA, or grapevine virus A, grapevine virus B, grapevine leafroll associated virus-3, and RubiscoL mRNA.

Evidence of improving prognosis in heart failure: trends in case fatality in 66 547 patients hospitalized between 1986 and 1995

BACKGROUND

Contemporary survival in unselected patients with heart failure and the population impact of newer therapies have not been widely studied. Therefore, we have documented case-fatality rates (CFRs) over a recent 10-year period.

METHODS AND RESULTS

In Scotland, all hospitalizations and deaths are captured on a single database. We have studied case fatality in all patients admitted with a principal diagnosis of heart failure from 1986 to 1995. A total of 66 547 patients (47% male) were studied. Median age was 72 years in men and 78 years in women. Crude CFRs at 30 days and at 1, 5, and 10 years were 19.9%, 44.5%, 76.5%, and 87.6%, respectively. Median survival was 1.47 years in men and 1.39 years in women (2.47 and 2. 36 years, respectively, in those surviving 30 days). Age had a powerful effect on survival, and sex, comorbidity, and deprivation had modest effects. One-year CF was 24.2% in those aged <55 years and 58.1% in those aged >84 years. After adjustment, 30-day CFRs fell between 1986 and 1995, by 26% (95% CI 15 to 35, P<0.0001) in men and 17% (95% CI 6 to 26, P<0.0001) in women. Longer term CFRs fell by 18% (95% CI 13 to 24, P<0.0001) in men and 15% (95% CI 10 to 20, P<0.0001) in women. Median survival increased from 1.23 to 1. 64 years.

CONCLUSIONS

Heart failure CF is much higher in the general population than in clinical trials, especially in the elderly. Although survival has increased significantly over the last decade, there is still much room for improvement.

Changes in expression of the lysosomal membrane glycoprotein, LAMP-1 in interdigital regions during embryonic mouse limb development, in vivo and in vitro

Syndactyly, a failure of the digits to separate into individual units, affects about 8 to 9 per 1000 newborns and results from an aberration of the normal development of the interdigital tissues. Limb digit separation is the result of programmed cell death (apoptosis). Lysosomes play a role in the process of cell self-destruction. Our experiment was designed to test the hypothesis that the intensity of interdigital lysosomes increases during the separation of digits in vivo and in vitro. The primary mouse monoclonal antibody, 1D4B, detects the presence of lysosomes by identifying the LAMP-1 glycoprotein on the lysosome cell membrane. In our experiment this antibody immunodetected interdigital lysosome proteins in serial sections of limbs from Swiss-Webster mouse embryos, gestational ages E12.5 through E15, key developmental stages for digit separation. Digit separation was associated with an increase in intensity of lysosomal protein staining. In E12.5 limbs, the presence of lysosomes was enriched in the distal aspect of the interdigital tissue. However, the number of lysosomes markedly increased in the E13 and E14 limbs, including the entire length and width of the interdigital tissue in the E14 limbs. This lysosomal protein presence in E14 limbs was significant compared to E12.5, E13, and E15 limbs. By day 12.5, the mouse embryo limb is committed to digit separation. Addition of retinoic acid to the culture medium of limbs earlier in development, such as E12, results in induction of the process of digit separation. Cultured E12 limbs that did not receive an addition of retinoic acid, did not show digit separation. We conclude that in the limb development process, the enrichment in interdigit LAMP-1 proteins, may indicate a relationship between lysosomes, apoptosis, and digit separation. We also conclude that retinoic acid has an important role in digit separation in vivo, as shown in limb development, and demonstrated through the addition of retinoic acid to media of cultured tissues.

The dominant negative Ras mutant, N17Ras, can inhibit signaling independently of blocking Ras activation

Ras plays an important role in a variety of cellular functions, including growth, differentiation, and oncogenic transformation. For instance, Ras participates in the activation of Raf, which phosphorylates and activates mitogen-activated protein kinase kinase (MEK), which then phosphorylates and activates extracellular signal-regulated kinase (ERK), a mitogen-activated protein (MAP) kinase. Activation of MAP kinase appears to be essential for propagating a wide variety of extracellular signals from the plasma membrane to the nucleus. N17Ras, a GDP-bound dominant negative mutant, is used widely as an interfering mutant to assess Ras function in vivo. Surprisingly, we observed that expression of N17Ras inhibited the activity and phosphorylation of Elk-1, a physiological substrate of MAP kinases, in response to phorbol myristate acetate. The activity and phosphorylation of the MAP kinase hemagglutinin epitope (HA)-ERK1 were not affected by N17Ras in response to the same stimulus. Additionally, expression of N17Ras, but not L61S186Ras, a GTP-bound interfering mutant, inhibited MEK-induced Elk-1 phosphorylation, suggesting that inhibition of Elk-1 may be unique to GDP-bound Ras mutants. Finally, we observed that V12Ras-induced focus formation in NIH3T3 cells is inhibited by coexpression of GDP-bound Ras mutants, such as N17, A15, and N17N69. Therefore, N17Ras and V12 Ras may be codominant with respect to Elk-1 activation and cellular transformation. These results indicate that N17Ras appears to have at least two distinguishable functions: interference with endogenous Ras activation and inhibition of Elk-1 and transfomation. Furthermore, our data imply the possibility that GDP-bound Ras, like N17Ras, may have a direct role in signal transduction.

Investing in the future of cardiovascular nursing as a research based profession: an international perspective

While we all face problems with promoting research even at a local level we must not lose sight of how much there is to gain from learning from each other. Together, on an international basis, we can make more progress in alleviating the suffering of our patients. The "head in the sand" approach (even on a nice warm beach in Australia or California) will be of little benefit to our patients or ourselves in the future. We must do more to take the good, but rare, examples of international collaboration in cardiovascular nursing and make them commonplace!

Personality disorders and coping among anxious older adults

This study examined the interrelationships among anxiety, personality disorders, and coping strategies in anxious older adults (n = 28; age range = 55-89; mean = 66.0), nonanxious older adults (n = 100, age range = 55-79, mean = 64.6 ), and anxious younger adults (n = 132; age range = 17-30; mean = 20.2). Younger participants were college students and older participants were community-based family members of the students or recruits from local senior centers. Participants completed the Coolidge Axis II Inventory, the Coping Orientations to Problems Experienced scale, and the Brief Symptom Inventory. Results indicated that the prevalence of generalized anxiety states was relatively low and similar in both older and younger groups and dependent on measurement scale and criterion. At least one personality disorder was found in 61% of the older persons group; obsessive-compulsive, schizoid, and avoidant were the most frequently assigned personality disorders. Anxious older adults had elevated rates of dependent and avoidant personality disorder compared with nonanxious older adults. Younger anxious persons were found to have significantly greater personality dysfunction compared with older anxious persons. Finally, coping differences existed between older anxious and older nonanxious adults and between older anxious and younger anxious adults. Implications for diagnosis and treatment of anxiety in older adults were discussed.

Pegylated liposomal adriamycin: a review of current and future applications

Anthracyclines such as adriamycin have a broad spectrum of activity in human tumours, but are limited, to an extent, by their non-selective delivery to a host of normal tissues and hence, subsequent toxicity. The development of liposomes has offered a drug delivery system with significant potential to target tumours whilst sparing normal tissues. A significant breakthrough has been achieved by coating the liposome with polyethylene glycol (pegylation), and thus altering the pharmacokinetics of the drug considerably. In this review, the authors discuss the promising data now emerging with pegylated liposomal adriamycin, and also describe possible future applications.

Social class, race/ethnicity, and incidence of breast, cervix, colon, lung, and prostate cancer among Asian, Black, Hispanic, and White residents of the San Francisco Bay Area, 1988-92 (United States)

BACKGROUND

To date only eight US studies have simultaneously examined cancer incidence in relation to social class and race/ethnicity; all but one included only black and white Americans. To address gaps in knowledge we thus investigated socioeconomic gradients in cancer incidence among four mutually exclusive US racial/ethnic groups-- Asian and Pacific Islander, black, Hispanic, and white-- for five major cancer sites: breast, cervix, colon, lung, and prostate cancer.

METHODS

We generated age-adjusted cancer incidence rates stratified by socioeconomic position using: (a) geocoded cancer registry records, (b) census population counts, and (c) 1990 census block-group socioeconomic measures. Cases (n = 70,899) were diagnosed between 1988 and 1992 and lived in seven counties located in California's San Francisco Bay Area.

RESULTS

Incidence rates varied as much if not more by socioeconomic position than by race/ethnicity, and for each site the magnitude - and in some cases direction - of the socioeconomic gradient differed by race/ethnicity and, where applicable, by gender. Breast cancer incidence increased with affluence only among Hispanic women. Incidence of cervical cancer increased with socioeconomic deprivation among all four racial/ethnic groups, with trends strongest among white women. Lung cancer incidence increased with socioeconomic deprivation among all but Hispanics, for whom incidence increased with affluence. Colon and prostate cancer incidence were inconsistently associated with socioeconomic position.

CONCLUSIONS

These complex patterns defy easy generalization and illustrate why US cancer data should be stratified by socioeconomic position, along with race/ethnicity and gender, so as to improve cancer surveillance, research, and control.

Is health-related quality of life among older, chronically ill patients associated with unplanned readmission to hospital?

BACKGROUND

Assessment of health-related quality of life (HRQL) is being used increasingly to assess the impact of treatment.

AIMS

To determine if HRQL, assessed shortly after acute hospitalisation, is associated with readmission to hospital.

METHODS

In a prospective, longitudinal study, 163 chronically ill, medical and surgical patients (mean age 67.0+/-16.3 years) discharged to home following acute hospitalisation were studied. HRQL was assessed at one month post-hospital discharge using the MOS 36-Item Short-Form Health Survey (SF-36). Patients were followed-up for six months thereafter to determine subsequent incidence of unplanned readmission.

RESULTS

HRQL as measured by the eight health dimensions of the SF-36, for the entire cohort, was lower relative to age and gender matched norms for the local population (p<0.01). During study follow-up, 47 (35%) patients had an unplanned readmission and one patient died. Patients who had an unplanned readmission demonstrated both significantly lower physical (32.2+/-9.8 vs 38.6+/-10.1: p<0.001) and mental (45.1+/-12.7 vs 49.9+/-12.3: p=0.03) health component scores in comparison to the remainder of the cohort. On multivariate analysis, independent correlates of unplanned readmission were: 1) presence of formal home assistance (OR 6.4: p<0.01), 2) > or =five prescribed medications (OR 2.4: p=0.04), 3) > or =two admissions in the six months before follow-up (OR 4.3: p<0.01) and 4) an SF-36 physical component score of < or =40 (OR 2.2: p=0.05).

CONCLUSIONS

In this cohort of predominantly older and chronically ill patients recently discharged from acute hospital care, relatively lower SF-36 physical health component scores were independently associated with an increased risk of subsequent unplanned readmission.

Effects of a multidisciplinary, home-based intervention on unplanned readmissions and survival among patients with chronic congestive heart failure: a randomised controlled study

BACKGROUND

Hospital admissions among patients with congestive heart failure (CHF) are a major contributor to health-care costs. Previous investigations suggest that the therapeutic efficacy of pharmacotherapy in CHF may be improved by strategies incorporating home visits to identify and address factors precipitating deterioration and resultant readmission.

METHODS

Chronic CHF patients discharged home after acute hospital admission were randomly assigned usual care (n=100) or a multidisciplinary, home-based intervention (n=100), consisting of a home visit by a cardiac nurse 7-14 days after discharge. The primary endpoint of the study was frequency of unplanned readmission plus out-of-hospital death within 6 months.

FINDINGS

During 6 months' follow-up there were 129 primary endpoint events in the usual-care group and 77 in the intervention group (p=0.02). More intervention-group than usual-care patients remained event-free (38 vs 51; p=0.04). Overall, there were fewer unplanned readmissions (68 vs 118; p=0.03) and associated days in hospital (460 vs 1173; p=0.02) among intervention-group patients. Hospital-based costs were Australian $490,300 for the intervention group and A$922,600 for the usual-care group (p=0.16); the mean cost of the intervention was A$350 per patient, and other community-based costs were similar for both groups.

INTERPRETATION

A home-based intervention has the potential to decrease the rate of unplanned readmissions and associated health-care costs, prolong event-free and total survival, and improve quality of life among patients with chronic CHF.

Hemodynamic effects of basal and stimulated release of endogenous nitric oxide in isolated human lungs

Background-We compared the hemodynamic responses to inhibition or stimulation of endothelial nitric oxide (NO) release of isolated explanted lungs from transplantation recipients with pulmonary hypertension and in normotensive unallocated donor lungs. Methods and Results-Lungs from 10 patients with severe pulmonary hypertension (SPH) and from 16 patients with severe chronic obstructive lung disease (COLD) were studied. Fourteen normotensive lungs were studied as controls. The lungs were perfused at a constant flow. In protocol 1 N(G)-nitro-L-arginine methyl ester caused a similar rise in baseline pulmonary artery pressure (PAP) that was similar in SPH (+17.1+/-4.2 mm Hg; n=5), COLD (+15.5+/-4.8 mm Hg; n=8), and control lungs (+14.5+/-1.5 mm Hg; n=7). Arterial occlusion demonstrated that most of the changes with N(G)-nitro-L-arginine methyl ester were precapillary. The response to sodium nitroprusside (10(-8) to 10(-4) mol/L) was similar in all groups. In protocol 2, the lungs were preconstricted, and acetylcholine (10(-9) to 10(-5) mol/L) caused a lesser fall in PAP in both COLD and SPH lungs compared with control (-41.9+/-8.6%, -55. 7+/-7.6%, and -73.2+/-2.5%, respectively; P<0.05), whereas sodium nitroprusside (10(-5) mol/L) decreased PAP to initial levels in all lungs. Conclusions-Stimulated release of NO is impaired in arteries of lungs with plexogenic or hypoxemic pulmonary hypertension. In contrast, basal release of NO appears to be maintained.

Inhibition of the mitogen-activated protein kinase kinase superfamily by a Yersinia effector

The bacterial pathogen Yersinia uses a type III secretion system to inject several virulence factors into target cells. One of the Yersinia virulence factors, YopJ, was shown to bind directly to the superfamily of MAPK (mitogen-activated protein kinase) kinases (MKKs) blocking both phosphorylation and subsequent activation of the MKKs. These results explain the diverse activities of YopJ in inhibiting the extracellular signal-regulated kinase, c-Jun amino-terminal kinase, p38, and nuclear factor kappa B signaling pathways, preventing cytokine synthesis and promoting apoptosis. YopJ-related proteins that are found in a number of bacterial pathogens of animals and plants may function to block MKKs so that host signaling responses can be modulated upon infection.

The role of ST-segment monitoring in assessment of acute myocardial infarction

Continuous ST-segment analysis is an accurate and noninvasive tool for monitoring coronary artery patency in patients with acute myocardial infarction. This type of monitoring also is easy to use and cost-effective. The critical care nurse plays a pivotal role in initiating ST-segment monitoring, promptly detecting ST-segment changes, and rapidly intervening to achieve myocardial reperfusion.

Intravenous ganciclovir prophylaxis for cytomegalovirus in heart, heart-lung, and lung transplant recipients

Cytomegalovirus (CMV) disease has had a significant clinical impact on the heart, heart-lung and lung transplant recipients in our centre. CMV disease has been so severe with CMV antibody-negative heart-lung transplant patients receiving organs from CMV antibody-positive donors (CMV-mismatched patients) that in 1986 we adopted the policy of not transplanting CMV-positive organs into CMV-negative heart-lung or lung recipients. In December 1992, we instituted a policy of providing intravenous ganciclovir (5 mg/kg twice a day for 28 days) during the immediate postoperative period for CMV-mismatched heart recipients and CMV antibody-positive heart-lung and lung patients, who have been the patients at greatest risk of severe CMV disease in our centre. A placebo group was not employed because of ethical considerations, ganciclovir having been shown to be effective for the treatment of CMV infections among transplant patients. Compared with a historical control group of patients receiving no prophylaxis, prophylactic ganciclovir reduced the incidence of CMV infection (39 % vs 91 %, P = 0.0006) and CMV disease (17 % vs 74 %, P = 0.0004) among CMV antibody-positive heart-lung recipients. Prophylactic ganciclovir did not significantly reduce the incidence of CMV infection or disease among heart or isolated lung recipients. Ganciclovir was well tolerated, with few adverse reactions. In the case of heart-lung transplant patients, one month of intravenous prophylactic ganciclovir significantly reduced the incidence of both CMV infection and disease when compared with patients who received no prophylaxis. With the lung transplant and heart transplant patients, there were no significant differences between the prophylaxis and nonprophylaxis groups, although there was a consistent trend towards less infection and disease in the prophylaxis groups.

Kinase suppressor of Ras forms a multiprotein signaling complex and modulates MEK localization

Genetic screens for modifiers of activated Ras phenotypes have identified a novel protein, kinase suppressor of Ras (KSR), which shares significant sequence homology with Raf family protein kinases. Studies using Drosophila melanogaster and Caenorhabditis elegans predict that KSR positively regulates Ras signaling; however, the function of mammalian KSR is not well understood. We show here that two predicted kinase-dead mutants of KSR retain the ability to complement ksr-1 loss-of-function alleles in C. elegans, suggesting that KSR may have physiological, kinase-independent functions. Furthermore, we observe that murine KSR forms a multimolecular signaling complex in human embryonic kidney 293T cells composed of HSP90, HSP70, HSP68, p50(CDC37), MEK1, MEK2, 14-3-3, and several other, unidentified proteins. Treatment of cells with geldanamycin, an inhibitor of HSP90, decreases the half-life of KSR, suggesting that HSPs may serve to stabilize KSR. Both nematode and mammalian KSRs are capable of binding to MEKs, and three-point mutants of KSR, corresponding to C. elegans loss-of-function alleles, are specifically compromised in MEK binding. KSR did not alter MEK activity or activation. However, KSR-MEK binding shifts the apparent molecular mass of MEK from 44 to >700 kDa, and this results in the appearance of MEK in membrane-associated fractions. Together, these results suggest that KSR may act as a scaffolding protein for the Ras-mitogen-activated protein kinase pathway.

Using problem-based learning as part of general dental practice vocational training

The use of problem-based learning as part of a vocational training scheme for vocational dental practitioners is described and evaluated. Problem-based learning is currently viewed as an effective means of delivering medical education and has been adopted as a principal style of education by many undergraduate medical and dental schools around the world.