Regional and Systemic Platelet Function Is Altered by Myocardial Ischemia-Reperfusion

Background: Myocardial reperfusion after short durations of ischemia causes prolonged contractile dysfunction (myocardial stunning). Recently it has also been suggested that ischemia-reperfusion results in impaired coronary endothelial function. Since platelet function is, in part, regulated by an intact functioning endothelium, platelet function could be expected to change during ischemia-reperfusion. However, the effect of ischemia and reperfusion on regional and systemic platelet function is unknown. The purpose of this study was to determine the effect of a brief period of myocardial ischemia followed by reperfusion on regional and systemic platelet function. Methods: Fourteen swine in an open-chest model underwent left anterior descending coronary artery (LAD) occlusion for 15 minutes followed by 120 minutes of reperfusion. Platelet aggregability in response to 5 µM ADP was determined simultaneously in the femoral (systemic; N = 14) and great cardiac (regional; N = 9) venous blood at baseline, during occlusion, and at 40 and 90 minutes after reperfusion. LAD blood flow and regional myocardial function were determined by standard methods. Results: Hemodynamics remained stable in all animals. During LAD occlusion platelet aggregability, increased only in the regional coronary circulation (126% of baseline, p =.0001). At 40 minutes of reperfusion systemic platelet aggregahility decreased (86% of baseline, p =.0001) and subsequently increased at 90 minutes at reperfusion in both the systemic (127% of baseline, p =.0001) and regional circula. tions (156% of baseline, p =.0001). Ischemia was evident by the absence ofdistal LAD flow during occlusion that returned during reperfusion and a typical response ofmyocardial stunning in each animal (stunning time = 47.7 +/- 5.2 minutes). Conclusions: This study demonstrates that platelet function is not static during ischemia-reperfusion. Instead, during ischemia regional platelet aggregability is increased. Systemic and regional platelet aggregability also increase during myocardial reperfusion. The mechanism of these responses is unknown but may be related to regional endathelial dysfunction created by ischernia. The response observed could also be explained by the release of proaggregatory mediators in the connary and/or systemic circulation during ischemia-reperfusion. The relative hyeraggregability observed following reperfusion may be relevant for further investigations of coronary artery reocclusion occurring after the relief of myocardial ischemia.

Measuring coping strategies in an educational intervention for individuals with psychiatric disabilities

Coping is a critical theoretical concept believed to be a mediator for successful outcomes produced through a variety of different social work interventions. This article describes an approach used to measure coping with stressors and was designed specifically for an intervention, the Michigan Supported Education Research Project, aimed at providing support for people with psychiatric disabilities to pursue college or vocational education. Hypothetical scenarios were developed that matched the content of material covered in the program. Open-ended responses were elicited from program participants as part of an in-person interview. Key findings included a participation effect on the number of positive coping strategies of participants and a significant relationship among some coping strategies and later outcomes. Implications for social work practice and research are identified.

Bovine viral diarrhea virus quasispecies during persistent infection

Analysis of viral genome sequences from two calves persistently infected with bovine viral diarrhea virus revealed a quasispecies distribution. The sequences encoding the glycoprotein E2 were variable, translating to a number of changes in predicted amino acid sequences. The NS3 region was found to be highly conserved in both animals. The number of E2 clones showing variant amino acids increased with the age of the animal and comparison of the consensus sequences at the different time points confirmed differences in the predicted E2 sequences over time. The immune tolerance that allows the lifelong persistence of this viral infection is highly specific. It is likely that some of the variant viruses generated within these animals will differ antigenically from the persisting virus and be recognized by the immune system. Evidence of an immune response to persisting virus infection was gathered from a larger sample of cattle. Serum neutralizing antibodies were found in 4 of 21 persistently infected animals. Accumulations of viral RNA in the lymph nodes of all animals examined, particularly in the germinal center light zone, may represent antigenic variants held in the form of immune complexes on the processes of follicular dendritic cells.

Effectiveness of supported education for individuals with psychiatric disabilities: results from an experimental study

In recent years post-secondary education has been recognized as a viable option in the psychosocial rehabilitation of individuals with mental illness. This study reports the first evidence of effectiveness of a supported education demonstration project which used an experimental design to compare the effects of different model types. A total of 397 participants were assigned to one of three conditions: group, classroom, and individual (control). At graduation from the program significant differences in program participation rates were found; group members participated most, followed by classroom participants, then those assigned to the individual condition. Also, immediate, intermediate, and long term outcomes were examined. On four immediate outcomes (motivation, satisfaction, enjoyment, and learning) significant participation effects were found (high participants scoring highest, followed by moderate participants, and then non-participants). On two intermediate outcome (empowerment and school efficacy) condition differences were found (classroom scoring highest followed by group, then individual). Although no condition differences were found on behavioral outcomes, the percentage of individuals enrolled in school or vocational education was more than twice that reported at baseline. Overall, the results demonstrated success in engaging participants, affecting self-perceptions, and increasing enrollment in post-secondary education.

Consumers as mental health providers: first-person accounts of benefits and limitations

Community support programs are increasingly establishing paid service positions designated exclusively for consumers. Project WINS (Work Incentives and Needs Study), a hybrid case management-vocational program for individuals with severe mental illness, used consumers as peer support specialists (PSSs) to supplement professional roles. Semistructured interviews were conducted with PSSs about 12 months after their employment ended. They identified substantial personal benefits specific to consumer-designated roles (e.g., a "safe" employment setting with accommodations) and general benefits from employment. Problems described were just as numerous, encompassing attitudes toward assigned peers and costs to their own well-being. Critical commentary addressed program operations (structure, supervision, and training needs) and problems in the mental health system. The authors discuss the changed sense of self that service provider roles can create for consumers and suggest that mental health administrators provide anticipatory socialization for this service innovation throughout their agencies and ongoing supports for consumers in their new roles.

Noncytopathogenic bovine viral diarrhea virus (BVDV) reduces cleavage but increases blastocyst yield of in vitro produced embryos

The growing application of in vitro embryo production systems that utilize slaughterhouse tissues of animals of unknown health status conveys the risk of disease transmission. One pathogen of concern in this regard is bovine viral diarrhea virus (BVDV), and the objective of this study was to investigate the effect of BVDV on in vitro embryonic development. A bovine in vitro embryo production system was experimentally infected with BVDV at 2 stages: prior to in vitro maturation by incubating cumulus-oocyte complexes (COC) with virus (strain Pe515; titer 10(6.2) tissue culture infective dose (TCID)50/mL) or vehicle for 2 h, and then during in vitro culture by the use of BVDV infected granulosa cells. Exposure to BVDV throughout in vitro production reduced cleavage rates (P = 0.01) but increased (P = 0.05) the number of embryos that reached the 8-cell stage when expressed as a percentage of cleaved oocytes. Blastocyst yield was increased by the presence of virus when expressed as a proportion of oocytes (P = 0.0034) or of those cleaved (P < 0.0001). The percentage of total blastocyst yield on Days 7, 8 and 9 for the control and virus treatments was 20, 51, 29 and 29, 41, and 29%, respectively, indicating that the rate of blastocyst development was nonsignificantly faster in the virus-treated group (P = 0.06). These results indicate that the presence of non-cytopathogenic BVDV in an in vitro production system may reduce cleavage rates but allow those cleaved to develop to blastocysts at a higher rate.

Maternal recognition of foetal infection with bovine virus diarrhoea virus (BVDV)--the bovine pestivirus

BACKGROUND

Pestiviruses are the veterinary viruses with genome homology to human hepatitis C virus (HCV). This group includes classical swine fever virus (CSFV), border disease virus of sheep (BDV) and bovine virus diarrhoea virus (BVDV). There are some similarities in the pathology of all three virus infections; in utero transmission to the foetus can cause early embryonic losses, severe congenital abnormalities and, particularly with BVDV, lifelong persistent infections. In situ hybridisation studies have demonstrated virus within reproductive tissues and the germinal centres of lymphoid tissue.

OBJECTIVES

To examine the immune response of cattle throughout their pregnancy following infection with bovine pestivirus (BVDV) during the first trimester (before 110 days).

STUDY DESIGN

In two experimental studies, heifers were infected with BVDV before 98 days gestation. Their antibody response was monitored during the remainder of the pregnancy. In another study, the antibody response of pregnant cattle was monitored following a natural infection of BVDV on a farm. Calves of the dams from all these three studies were examined, following birth, for persistent BVDV infection.

RESULTS

It was observed that in dams carrying persistently infected foetuses, the immune response was markedly higher (13811 + 1273 U ELISA antibody) than in those dams carrying uninfected foetuses (2542+/-588 U ELISA antibody). These results were used to establish an antibody threshold (10000 U ELISA antibody) to predict the virus status of unborn calves during a farm outbreak of BVDV infection. The combined results of experimental and farm studies showed that in dams with low antibodies, 5/15 calves were infected whereas in dams with high antibodies, 17/19 calves were infected.

CONCLUSIONS

The predictive reliability of the assay appeared valuable but not secure. The ability of BVDV to infect the foetus with consequent maternal recognition, whilst remaining inaccessible to maternal immune exclusion, is a novel finding.

Genome instability in BVDV: an examination of the sequence and structural influences on RNA recombination

The cytopathogenic biotype of the pestivirus, bovine viral diarrhea virus, is frequently a product of nonhomologous recombination in the region of the genome encoding the viral NS2-NS3 proteins. The possibility that sequences or structures in this region contributed to a hotspot for RNA recombination was examined. A PCR-based strategy was used to examine viral genomic RNA isolated from tissue samples of cattle persistently infected with the noncytopathogenic biotype of the virus. Analysis of two different regions of the viral genome revealed that recombination was not restricted to particular sequences. Alignment of the genomic sequences undergoing recombination and examination of the predicted secondary structures of the participating RNAs revealed that the dissociation of partial, newly synthesized negative strand RNAs from the positive strand template occurred at many different sites on the molecule. Similarly, it appeared that the reassociation of the RNA polymerase complex with a second positive strand template was frequently influenced by short regions of homology between the nascent RNA strand and open secondary structures in the template molecule.

Harbinger. I: The development and evaluation of the first PACT replication

While Assertive Community Treatment (originally known as the PACT program) is now recognized around the world as an effective model for rehabilitation of persons with severe mental illness, this was not the case 20 years ago. Harbinger of Grand Rapids, in Kent County, Michigan, was the first replication of the PACT model which sought fidelity and included an experimental design for assessing effectiveness. The design and results are presented from an initial 30-month and a follow-up 66-month evaluation of Harbinger. The 30-month evaluation showed significant differences favoring Harbinger vs, the control group on independent living, employment, and client functioning. At 66-months, there were fewer experimental-control group differences. The differences in results are analyzed in terms of design and data collection problems, changes in the treatment environment for the control group, and the longitudinal course of mental illness. The discussion focuses on next steps in ACT research, utilizing program theory to better establish the mechanisms for successful intervention models.

Differences in dermal analogs influence subsequent pigmentation, epidermal differentiation, basement membrane, and rete ridge formation of transplanted composite skin grafts

This study evaluated the in vitro and in vivo function of composite skin equivalents based on two different dermal analogs. Keratinocytes derived from the same dark-skinned neonatal foreskins were seeded onto both acellular human dermis and fibroblast-contracted collagen gels. Each type of composite graft readily formed an epithelium in vitro. However, the undulating surface of the acellular dermis acted as a template and organized the seeded keratinocytes into a rete ridge-like pattern, whereas the smooth surface of the fibroblast-contracted collagen gels generated an epithelium with a linear basal layer. Moreover, when acellular dermis was used, the composite grafts demonstrated enhanced melanocyte proliferation. When transplanted to athymic mice, both composite grafts formed a fully differentiated human epidermis, but repigmentation of the grafts when acellular dermis was used was more extensive and only the epidermis on the fibroblast-contracted collagen gels showed signs of hyperproliferation at 6 weeks after grafting. These results demonstrate that the type of dermal analog incorporated into a composite skin graft can influence the subsequent functionality of the skin substitute.

Pretreatment with an inhibitor of mac-1 alters regional and systemic platelet function during ischemia-reperfusion in swine

Myocardial ischemia-reperfusion alters regional and systemic platelet function. The aim of our study was to elucidate the role of the Mac-1 receptor in changes of platelet function by using the leumedin, NPC-15669, an inhibitor of Mac-1 upregulation. In an open-chest swine model (n = 15), the treatment group (n = 6) received NPC-15669 (10 mg/kg loading dose over 12 min at the rate of 5 ml/min at the onset of left-anterior descending coronary artery occlusion, followed by constant infusion at 6 mg kg-1 h-1 during 90 min of reperfusion). Regional platelet aggregation (response to 5 microM ADP) increased after 15 min occlusion (126% of baseline) and at 90 min of reperfusion (156% of baseline). This increase in platelet aggregability was inhibited by NPC-15669 (83% of baseline after 15 min occlusion and 98% of baseline at 90 min reperfusion, both p < 0.001 compared to control). Systemic platelet function was not affected by NPC-15669 after 15 min occlusion (102% of baseline vs. 96% of baseline for control, p = NS). At 90 min of reperfusion platelet function was increased in controls (131% of baseline) and not affected by NPC-15669 (126% of baseline, p = NS). Myocardial neutrophil accumulation did not differ between the control and treatment groups. Inhibition of Mac-1 upregulation by NPC-15669 attenuates the increased regional platelet aggregability resulting from myocardial ischemia-reperfusion, with a less marked effect on the systemic response. The data suggest that Mac-1 may modulate regional platelet responses induced by ischemia-reperfusion. The increased aggregability of platelets during ischemia and reperfusion and its attenuation by inhibition of Mac-1 may be relevant for future strategies to reduce coronary arterial occlusion by platelet thrombi.

Detection of bovine viral diarrhoea virus antigen and RNA in oviduct and granulosa cells of persistently infected cattle

Large-scale in vitro bovine embryo production systems commonly use genital tracts obtained from an abattoir as a source of both cumulus-oocyte complexes and co-culture feeder cells. Tissues derived from this source may be contaminated with non-cytopathogenic bovine viral diarrhoea virus (BVDV) since, in several countries surveyed, approximately 1% of animals tested are persistently infected with this pathogen. Therefore, the use of such material in in vitro fertilization systems presents a potential risk for the transmission of BVDV to bovine embryos and via embryo transfer. This potential was investigated by obtaining oviduct epithelial cells and granulosa cells, which are commonly used as feeder cells, from cattle persistently infected with BVDV and examining them for the presence of BVD viral antigen (p80 non-structural protein and gp53 envelope glycoprotein) by indirect immunofluorescent histochemistry, and also viral RNA (encoding the p80 region) by in situ hybridization. In addition, titres of virus present in oviduct, ovary and blood were assayed by immunodetection on calf testis cell cultures. Luminal epithelial cells from the oviduct and primary cultures of granulosa cells and oviduct epithelial cells from such cattle were shown to contain both viral antigen and RNA. The susceptibility of both cell types to BVDV infection was further established by inoculating primary cell cultures of cells derived from cattle not infected with BVDV with a cloned isolate of non-cytopathogenic BVDV (Pe515). RNA encoding BVDV and the antigen were detected 12 h after inoculation.(ABSTRACT TRUNCATED AT 250 WORDS)

A rapid method for mRNA detection in single-cell biopsies from preimplantation-stage bovine embryos

Major questions concerning the control of development and gene expression at the cellular level are still unanswered. Nowhere is this more evident than during the earliest stages of development and embryogenesis. This study describes the detection of specific gene transcripts in single cells derived from bovine embryos. Following in vitro fertilization (IVF) and in vitro culture (IVC) of bovine embryos, small groups of cells and even single blastomeres from 32 to 64-cell embryos were micromanipulated into individual tubes for analysis of cytoplasmic RNAs. Reverse transcriptase-PCR was applied to cell lysates for the amplification of beta-actin mRNA transcripts. Primers were designed to flank an intron expected to be present within genomic DNA sequences, thus allowing for simple differentiation between DNA- and RNA-derived amplification products. Using a 50-cycle amplification profile, a 260 bp band could be seen as a PCR product derived from a single blastomere following electrophoresis in an ethidium bromide-stained agarose gel. The identity of the band was verified by DNA sequence determination and diagnostic restriction digestion. Lysates derived from single blastomeres in this way have been used for simultaneously phenotyping multiple RNA products. This capability allows the spatial analysis of gene expression and development within embryos from the earliest stages of cellular differentiation.

Youth risk behavior surveillance--United States, 1993

Priority health risk behaviors that contribute to the leading causes of mortality, morbidity, and social problems among youth and adults often are established during youth, extend into adulthood, and are interrelated. The Youth Risk Behavior Surveillance System (YRBSS) monitors six categories of priority health risk behaviors among youth and youth adults: behaviors that contribute to unintentional and intentional injuries, tobacco use, alcohol and other drug use, sexual behaviors, dietary behaviors, and physical activity. The YRBSS includes a national, school-based survey conducted by CDC and state and local school-based surveys conducted by state and local education agencies. This report summarizes results from the national survey, 24 state surveys, and nine local surveys conducted among high school students during February through May 1993. In the United States, 72% of all deaths among school-age youth and young adults are from four causes: motor vehicle crashes, other intentional injuries, homicide, and suicide. Results from the 1993 YRBSS suggest many high school students practice behaviors that may increase their likelihood of death from these four causes: 19.1% rarely or never use a safety belt, 35.3% had ridden during the 30 days preceding the survey with a driver who had been drinking alcohol, 22.1% had carried a weapon during the 30 days preceding the survey, 80.9% ever drank alcohol, 32.8% ever used marijuana, and 8.6% had attempted suicide during the 12 months preceding the survey. Substantial morbidity and social problems among adolescents also result from unintended pregnancies and sexually transmitted diseases including HIV infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Youth risk behavior surveillance--United States, 1993

PROBLEM/CONDITION

Priority health risk behaviors that contribute to the leading causes of mortality, morbidity, and social problems among youth and adults often are established during youth, extend into adulthood, and are interrelated.

REPORTING PERIOD

February through May 1993.

DESCRIPTION OF SYSTEM

The Youth Risk Behavior Surveillance System (YRBSS) monitors six categories of priority health risk behaviors among youth and young adults: behaviors that contribute to unintentional and intentional injuries, tobacco use, alcohol and other drug use, sexual behaviors, dietary behaviors, and physical activity. The YRBSS includes a national, school-based survey conducted by CDC and state and local school-based surveys conducted by state and local education agencies. This report summarizes results from the national survey, 24 state surveys, and nine local surveys conducted among high school students during February through May 1993.

RESULTS AND INTERPRETATION

In the United States, 72% of all deaths among school-age youth and young adults are from four causes: motor vehicle crashes, other unintentional injuries, homicide, and suicide. Results from the 1993 YRBSS suggest that many high school students practice behaviors that may increase their likelihood of death from these four causes: 19.1% rarely or never used a safety belt, 35.3% had ridden with a driver who had been drinking alcohol during the 30 days preceding the survey, 22.1% had carried a weapon during the 30 days preceding the survey, 80.9% ever drank alcohol, 32.8% ever used marijuana, and 8.6% had attempted suicide during the 12 months preceding the survey. Substantial morbidity and social problems among adolescents also result from unintended pregnancies and sexually transmitted diseases, including human immunodeficiency virus (HIV) infection. YRBSS results indicate that in 1993, 53.0% of high school students had had sexual intercourse, 52.8% of sexually active students had used a condom during last sexual intercourse, and 1.4% ever injected an illegal drug. Among adults, 67% of all deaths are from three causes: heart disease, cancer, and stroke. In 1993, many high school students practiced behaviors that may increase the risk for these health problems: 30.5% of high school students had smoked cigarettes during the 30 days preceding the survey, only 15.4% had eaten five or more servings of fruits and vegetables during the day preceding the survey, and only 34.3% had attended physical education class daily.

ACTIONS TAKEN

YRBSS data are being used nationwide by health and education officials to improve school health policies and programs designed to reduce risks associated with the leading causes of mortality and morbidity. At the national level, YRBSS data are being used to measure progress toward achieving 26 national health objectives and one of eight National Education Goals.

Weight control practices of U.S. adolescents and adults

OBJECTIVE

To estimate the prevalence of various weight-loss practices in U.S. adolescents and adults.

DESIGN

The Youth Risk Behavior Survey, a self-administered survey of a random sample of high school students in 1990 and the Behavioral Risk Factor Surveillance System, a random-digit dial survey in 1989.

SETTING

Thirty-eight states and the District of Columbia.

PARTICIPANTS

High school students (n = 11,467) and adults 18 years and older (n = 60,861).

RESULTS

Among high school students, 44% of female students and 15% of male students reported that they were trying to lose weight. An additional 26% of female students and 15% of male students reported that they were trying to keep from gaining more weight. Students reported that they had used the following weight control methods in the 7 days preceding the survey: exercise (51% of female students and 30% of male students); skipping meals (49% and 18%, respectively); taking diet pills (4% and 2%, respectively); and vomiting (3% and 1%, respectively). Among adults, 38% of women and 24% of men reported that they were trying to lose weight, whereas 28% of each sex reported that they were trying to maintain their weight.

CONCLUSIONS

Attempts to lose or maintain weight are very prevalent among both adolescents and adults, especially among females.

Characteristics of a retrovirus associated with Jembrana disease in Bali cattle

A virus causing Jembrana disease in Bali cattle (Bos javanicus) was demonstrated to have characteristics of a retrovirus. Reverse transcriptase activity was detected in virus purified by sucrose gradient centrifugation. Electron microscopic examination of tissue from the affected cattle indicated that the virus matured by C-type budding through the plasma membrane and into intracytoplasmic vacuoles of cells in lymphoid tissue, with the formation of circular enveloped virus particles ranging in diameter from 96 to 124 nm with an eccentric nucleoid. Western immunoblotting using sera from recovered animals demonstrated virus proteins of M(r) 100K, 45K, 42K, 33K, 26K, 16K and 14K. The 26K protein of Jembrana disease virus cross-reacted in Western blots with the 26K capsid protein of bovine immunodeficiency virus (BIV). The apparent morphogenesis, protein structure and antigenic relationship with BIV suggested the virus was a lentivirus.

Nucleotide sequence and expression in Escherichia coli of cDNAs encoding papaya proteinase omega from Carica papaya

We have cloned and sequenced two similar, but distinct, cDNAs from both fruit and leaf tissues of Carica papaya. The C-terminal portion of the predicted amino acid (aa) sequence of one of the clones has complete identity with the mature enzyme sequence of the cysteine proteinase papaya proteinase omega (Pp omega). The second clone contains ten individual bp changes compared with the first and encodes a protein with three single-aa substitutions, only one of which is located in the mature sequence, but most noticeably carries an additional 19-aa C-terminal extension. The clones encode pre-pro precursor isoforms of Pp omega. The former of these clones has been expressed in Escherichia coli using a T7 polymerase expression system to produce insoluble pro-enzyme which has been solubilized and refolded to yield auto-activable pro-Pp omega.

Changes in activity of porcine phospholipase A2 brought about by charge engineering of a major structural element to alter stability

We have modified the stability of porcine phospholipase A2 by charge engineering. The mutations are situated at the N-terminal of a major helix and are N89D and N89D/E92Q. This engineering has significantly altered the activity of the enzyme to aggregated and monomeric substrates. A N89D/E92K mutant is more stable but considerably less active than wild type. An N89D mutant is more stable and of similar activity to wild type. The substantial change in activity may be due to direct interaction of residue 92 with aggregated substrate or may be via second calcium binding. Second calcium binding may be more probable as activity against monomers is also affected. Additional calcium binding may therefore be an important way of manipulating the activity of phospholipase A2.

An inducible gene expression system for Neurospora crassa

Neurospora crassa acetyl CoA synthetase is highly induced when the growing mycelium is transferred from sucrose- to acetate-based medium. The inducible promoter of this gene has been isolated and used to control the expression of glutamate dehydrogenase. Transformants containing this expression cassette show gdh levels up to 25 times higher than the nontransformed host strain. This expression cassette will form the basis of a system of heterologous gene expression.

A novel method for the purification of porcine phospholipase A2 expressed in E. coli

Porcine phospholipaseA2 expressed in E. coli as a fusion protein was isolated, renatured and specifically cleaved by trypsin as described in (1). Active phospholipaseA2, was purified to homogeneity on a column of PBE-94 over a pH region 7.4-4.5. Using this method, several phospholipase A2 mutant enzymes have now been purified in a single step and all behaved identically during chromatofocusing. The method will therefore be extremely useful not only for those interested in understanding the structure-function relationships of phospholipaseA2 but also for preparing the enzyme in large quantities for industrial and pharmaceutical purposes.