Changing demographics and immunity to vaccine preventable diseases in people with HIV in Ireland

BACKGROUND

HIV infection is associated with an increased risk of morbidity and mortality from vaccine preventable infections. This research describes, in the context of changing patient demographics, the seroprevalence of vaccine preventable viral infections among attendees of the largest centre for HIV positive patients in Ireland.

METHODS

Baseline serum IgG results for measles, mumps, rubella, varicella zoster virus (VZV) & hepatitis A, as well as hepatitis B sAg, cAb and sAb results, were retrieved for 2534 clinic attendees attending in 2018. Results were available for between 990 and 2363 attendees (39-93%), depending on the test, and were compared with 2013 clinic data.

RESULTS

There was a 35% increase in attendees in 2018 when compared to 2013. The largest increase was in attendees of South American origin. In 2018, males accounted for 73% of the entire cohort and the HIV acquisition risk for 48% of attendees was MSM. 47% of attendees were originally from Ireland. Among those tested, 33% were susceptible to at least one component of the MMR vaccine. 5% were VZV non-immune (significantly associated with younger age and the acquisition risk status of injection drug use). 21% were hepatitis A non-immune (significantly associated with younger age and being of European or South American origin). 32% were hepatitis B cAb seropositive (significantly associated with older age, injection drug use status and being originally from Africa). 3% demonstrated hepatitis B sAg positivity. 64% had hepatitis B sAb ≥ 10mIU.

CONCLUSION

In a cohort of attendees to an HIV clinic in a large urban setting, the susceptibility to several common vaccine preventable viral infections, in particular MMR and hepatitis A and B, was high. These results highlight the importance of proactive screening and immunisation to help protect this high risk patient group against vaccine preventable diseases.

The Current Use of Lumbar Puncture in a General Paediatric Unit

Aim This study evaluated the use of Lumbar Puncture (LP) in a general paediatric unit over a 3-year period. Methods Index patients, who had a successful LP, were identified from the microbiology database and failed LP procedures were identified from a chart review of the serum PCR database. Data abstracted included 1) patient age, 2) LP indication, 3) LP procedure outcome; classified as atraumatic, traumatic or failed, 4) grade of doctor undertaking the procedure and 5) the final diagnosis. Results We identified 104 paediatric patients, of whom 29(27.9%) were neonates. LP was indicated for the evaluation of acute undifferentiated illnesses, with 33 (31.7%) patients having fever without source beyond the neonatal period and 16 (15.4%) being neonates with fever. A CSF sample was obtained in 96 (92.4%) patients, with 71 (73.9%) being atraumatic. Successful LP was undertaken by Consultants in 4 (4.1%), Registrars in 83 (86.5%) and SHOs in 9 (9.4%) patients. 14 (14.6%) patients had positive CSF cultures with an additional 23 having positive cultures or serology (9 blood cultures, 11 urine cultures and 3 positive serum PCR). Conclusion Skill in LP performance is still required, to evaluate acute undifferentiated illness, in general paediatric units and ancillary methods to aid SHOs with LP skill development is desirable.

Indirect impact of rotavirus vaccination on viral causes of acute gastroenteritis in the elderly

BACKGROUND

Rotavirus is considered a childhood infection causing acute gastroenteritis however, it also causes disease in adults which may be underestimated due to less frequent testing in this age-group.

OBJECTIVES

To determine if paediatric rotavirus vaccination, introduced into Ireland in December 2016, affected the viral aetiology in those aged ≥65 yrs presenting with gastroenteritis in the pre- and post-vaccination years. Additionally, rotavirus genotypes in this age-group will be described.

METHODS

Faecal samples from 2015 to 2019 for the investigation of gastroenteritis were tested by real-time (RT-) PCR for norovirus, adenovirus, rotavirus, Rotarix, astrovirus and sapovirus. Rotaviruses were genotyped by multiplex real-time RT-PCR or hemi-nested RT-PCR and a proportion confirmed by sequencing.

RESULTS

22,593 samples from adults aged ≥65 yrs were tested and 2566 (11 %) had ≥1 virus detected. Of 2566 positive samples, norovirus was detected in 82 %, rotavirus 9 %, sapovirus 6 %, astrovirus 3 % and adenovirus 1 %. Rotavirus and norovirus infections decreased between pre and post-vaccine year groups p < 0.001, whereas sapovirus, astrovirus and adenovirus remained unchanged. Between 2015-16 and 2018-19, G2P[4] increased and G4P[8] decreased, p < 0.001. In 2015-2019 there were 37 rotavirus outbreaks. Five geriatric outbreaks were genotyped and caused by G4P[8] (n = 1), G1P[8] (n = 1), G2P[4] (n = 2) and G12P[8] (n = 1).

CONCLUSION

Rotavirus causes acute gastroenteritis in older people. Paediatric vaccination may have contributed to a decline in infections in the elderly; nevertheless, rotavirus continued to circulate in older people following vaccine introduction. Genotype distribution changed between the pre- and post-vaccine era however genotypes in outbreak and endemic settings were comparable.

The gut virome in Irritable Bowel Syndrome differs from that of controls

Irritable Bowel Syndrome (IBS), the most common gastrointestinal disorder, is diagnosed solely on symptoms. Potentially diagnostic alterations in the bacterial component of the gut microbiome (the bacteriome) are associated with IBS, but despite the known role of the virome (particularly bacteriophages), in shaping the gut bacteriome, few studies have investigated the virome in IBS. We performed metagenomic sequencing of fecal Virus-Like Particles (VLPs) from 55 patients with IBS and 51 control individuals. We detected significantly lower alpha diversity of viral clusters comprising both known and novel viruses (viral 'dark matter') in IBS and a significant difference in beta diversity compared to controls, but not between IBS symptom subtypes. The three most abundant bacteriophage clusters belonged to the Siphoviridae, Myoviridae, and Podoviridae families (Order Caudovirales). A core virome (defined as a cluster present in at least 50% of samples) of 5 and 12 viral clusters was identified in IBS and control subjects, respectively. We also identified a subset of viral clusters that showed differential abundance between IBS and controls. The virome did not co-vary significantly with the bacteriome, with IBS clinical subtype, or with Bile Acid Malabsorption status. However, differences in the virome could be related back to the bacteriome as analysis of CRISPR spacers indicated that the virome alterations were at least partially related to the alterations in the bacteriome. We found no evidence for a shift from lytic to lysogenic replication of core viral clusters, a phenomenon reported for the gut virome of patients with Inflammatory Bowel Disease. Collectively, our data show alterations in the virome of patients with IBS, regardless of clinical subtype, which may facilitate development of new microbiome-based therapeutics.

The role of rhinovirus infections in young children with cystic fibrosis

Rhinovirus (RV) is an important virus in children with chronic respiratory conditions such as asthma; however, little is known about its role in CF. Our aim was to examine the prevalence and clinical impact of different RV species in young children with CF. We collected clinical data and nasal swabs on patients at home and in the hospital setting. Parents filled out symptom diaries and collected nasal swabs when their children were symptomatic and asymptomatic. A novel RV typing PCR assay was used to determine the RV species present. We collected 55 nasal swab samples from ten preschool CF patients over a six month period. The quality of parent collected samples at home was sufficient for PCR analysis. RV was the most common virus detected in young children with CF. There was no difference in the frequency of RV species between symptomatic and asymptomatic subjects. However, parental home-sampling is an acceptable and feasible approach to monitoring young children with CF.

Diagnosis of rotavirus infection in a vaccinated population: Is a less sensitive immunochromatographic method more suitable for detecting wild-type rotavirus than real-time RT-PCR?

BACKGROUND

Diagnosis of wild-type rotavirus disease may be complicated by the detection of vaccine-derived virus which can be detected in stool samples following immunisation. We evaluate an immunochromatographic assay and real-time RT-PCR to determine which is more suitable for the detection of wild-type rotavirus.

OBJECTIVES

To compare the Ct values of wild-type rotavirus and Rotarix determined by real-time RT-PCR. To establish the Ct value corresponding to the limit of detection of the immunochromatographic Combi-Strip method (Coris, BioConcept).

STUDY DESIGN

Retrospective review of real-time RT-PCR Ct values was performed on 100 samples tested by a pan-rotavirus assay (n = 50 wild-type, n = 50 Rotarix). Secondly the limit of detection of the Combi-Strip assay was determined by testing; wild-type rotavirus (n = 33, Ct range 6.85-34.26) samples, Rotarix (n = 9, Ct range 20.86-34.26) samples and rotavirus negative (n = 21) samples.

RESULTS

The median Ct of 50 wild-type rotavirus was Ct 12.43; range 6.11-32.66 compared with the median of 50 Rotarix, Ct 29.09; range 18.91-35.28, p=<0.0001. The limit of detection of the Combi-Strip method was approximately Ct 18. The 21 rotavirus negative samples were negative by real-time RT-PCR and Combi-Strip.

CONCLUSIONS

We found the Ct value was significantly lower, and therefore the viral load higher, for wild-type rotavirus compared to detectable Rotarix. The Combi-Strip assay detects most wild-type infections; however, it lacks sensitivity to detect low-level wild-type rotavirus and, beneficially, is unlikely to detect Rotarix. It is not a more suitable method than real-time RT-PCR when a definitive rotavirus result is required.

Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

Lamivudine treatment and outcome in pregnant women with high hepatitis B viral loads

Perinatal transmission is the most common mode of hepatitis B virus (HBV) transmission and is a leading cause of chronic infection worldwide. Maternal treatment with lamivudine (LAM) can result in a rapid and significant reduction in HBV viral load (VL) and, thus, mitigate the risk of mother-to-child transmission (MTCT). The aim of this study was to retrospectively evaluate the safety of LAM treatment administered in the third trimester of pregnancy and determine the influence, if any, on infant outcome. The medical charts of all HBV surface antigen (HBsAg)-positive women eligible for treatment with LAM and who registered for antenatal care between 2007 and 2012 were retrospectively reviewed. During the 6-year period, 45 women met the criteria for LAM treatment. Thirty-six women (80 %) accepted treatment; the remaining women declined treatment (5), defaulted from care (3) or transferred to another maternity unit (1). The median duration of treatment was 11.4 weeks (range 5.3-17.4) and the median baseline VL was 1.4 × 10(8) IU/mL (range 1.8 × 10(7)-1.7 × 10(8)). The median VL at delivery was 2.3 × 10(5) IU/mL and 60 % of women achieved a VL reduction >2 log10 IU/mL before delivery. No cases of perinatal transmission occurred in the infants born to mothers who received treatment; however, one infant, born to a mother who defaulted from care, was HBV-infected at 8 months. The results suggest that LAM therapy in highly viraemic HBV-infected pregnant women could lower the rate of vertical transmission.

Effectiveness of 2010/2011 seasonal influenza vaccine in Ireland

We conducted a case-control study to estimate the 2010/2011 trivalent influenza vaccine effectiveness (TIVE) using the Irish general practitioners' influenza sentinel surveillance scheme. Cases were influenza-like illness (ILI) patients with laboratory-confirmed influenza. Controls were ILI patients who tested negative for influenza. Participating sentinel general practitioners (GP) collected swabs from patients presenting with ILI along with their vaccination history and other individual characteristics. The TIVE was computed as (1 - odds ratiofor vaccination) x100%. Of 60 sentinel GP practices, 22 expressed interest in participating in the study and 17 (28%) recruited at least one ILI patient. In the analysis, we included 106 cases and 85 controls. Seven controls (8.2%) and one influenza case (0.9%) had been vaccinated in 2010/2011. The estimated TIVE against any influenza subtype was 89.4% [95% CI: 13.8; 99.8%], suggesting a protective effect against GP-attended laboratory confirmed influenza. This study design could be used to monitor influenza vaccine effectiveness annually but sample size and vaccination coverage should be increased to obtain precise and adjusted estimates.

Industrial perspective: capturing the benefits of genomics to Irish cattle breeding

Genomics is a technology for increasing the accuracy with which the genetic merit of young potential breeding animals can be determined. It enables earlier selection decisions, thus reducing generation intervals and gives rise to more rapid annual rates of genetic gain. Recently, the cost of genomics has reduced to the point where it enables breeding-program costs to be reduced substantially. Ireland has been a rapid adopter of genomics technology in its dairy-cattle breeding program, with 40% of dairy-cow artificial inseminations in 2010 being from bulls evaluated using genomic information. This rapid adoption has been facilitated by a comprehensive database of phenotypes and genotypes, strong public funding support for applied genomics research, an international network of collaborators, a short path between research and implementation, an overall selection index which farmers use in making breeding decisions, and a motivated and informed breeding industry. The shorter generation interval possible with genomic selection strategies also allows exploitation of the already accelerating rate of genetic progress in Ireland, because elite young dairy bulls are considerably superior to the small numbers of bulls that entered progeny test 6 years ago. In addition, genomics is having a dramatic impact on the artificial-insemination industry by substantially reducing the cost of entry, the cost of operation, and shifting the focus of breeding from bulls to cows. We believe that the current industry structures must evolve substantially if Irish cattle farmers are to realise the full benefits of genomics and be protected from related risks. Our model for future dairy breeding envisages a small number of ‘next generation research herds’, 1000 ‘bull breeder herds’ and an artificial-insemination sector using 30 new genomically selected bulls per year to breed the bulk of replacements in commercial milk-producing herds. Accurate imputation from a low-density to a higher-density chip is a key element of our strategy to enable dairy farmers to afford access to genomics. This model is capable of delivering high rates of genetic gain, realising cost savings, and protecting against the risks of increased inbreeding and suboptimal breeding goals. Our strategy for exploiting genomic selection for beef breeding is currently focussed on genotyping, using a high-density chip, a training population of greater than 2000 progeny-tested bulls representing all the main beef breeds in Ireland. We recognise the need for a larger training population and are seeking collaboration with organisations in other countries and populations.

Potential role of asymptomatic kitchen food handlers during a food-borne outbreak of norovirus infection, Dublin, Ireland, March 2009

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First reported cases of human adenovirus serotype 14p1 infection, Ireland, October 2009 to July 2010

We report the first nine confirmed cases of human adenovirus 14p1 infection (HAdV-14p1), identified at different locations in Ireland between October 2009 and July 2010. These were the first notifications in Ireland and all were sporadic cases. Following these notifications, the Health Protection Surveillance Centre set up an enhanced surveillance system for HAdV-14p1infection. Seven cases were male and five were aged less than one year. Three patients died, giving a case fatality rate of 33%. It should be noted that cases presented here were diagnosed on presentation to hospital and may represent the severe end of the spectrum of HAdV 14 disease in Ireland.

First reported cases of human adenovirus serotype 14p1 infection, Ireland, October 2009 to July 2010

We report the first nine confirmed cases of human adenovirus 14p1 infection (HAdV-14p1), identified at different locations in Ireland between October 2009 and July 2010. These were the first notifications in Ireland and all were sporadic cases. Following these notifications, the Health Protection Surveillance Centre set up an enhanced surveillance system for HAdV-14p1 infection. Seven cases were male and five were aged less than one year. Three patients died, giving a case fatality rate of 33%. It should be noted that cases presented here were diagnosed on presentation to hospital and may represent the severe end of the spectrum of HAdV 14 disease in Ireland.

Data quality of 5 years of central norovirus outbreak reporting in the European Network for food-borne viruses

BACKGROUND

The food-borne viruses in Europe (FBVE) network database was established in 1999 to monitor trends in outbreaks of gastroenteritis due to noroviruses (NoVs), to identify major transmission routes of NoV infections within and between participating countries and to detect diffuse international food-borne outbreaks.

METHODS

We reviewed the total of 9430 NoV outbreak reports from 13 countries with date of onset between 1 January 2002 and 1 January 2007 for representativeness, completeness and timeliness against these objectives.

RESULTS

Rates of reporting ranged from a yearly average of 1.8 in 2003 to 11.6 in 2006. Completeness of reporting of an agreed minimum dataset improved over the years, both for epidemiological and virological data. For the 10 countries that provided integrated (epidemiological AND virological) reporting over the 5-year period, the completeness of the minimum dataset rose from 15% in 2003 to 48% in 2006. Two countries have not been able to combine both data types due to the structure of the national surveillance system (England and Wales and Germany). Timeliness of reporting (median days between the onset of an outbreak and the date of reporting to the FBVE database) differed greatly between countries, but gradually improved to 47 days in 2006.

CONCLUSION

The outbreaks reported to the FBVE reflect the lack of standardization of surveillance systems across Europe, making direct comparison of data between countries difficult. However, trends in reported outbreaks per country, distribution of NoV genotypes, and detection of diffuse international outbreaks were used as background data in acute questions about NoV illness and the changing genotype distribution during the 5-year period, shown to be of added value. Integrated reporting is essential for these objectives, but could be limited to sentinel countries with surveillance systems that allow this integration. For successful intervention in case of diffuse international outbreaks, completeness and timeliness of reporting would need to be improved and expanded to countries that presently do not participate.

Global gene expression during nitrogen starvation in the rice blast fungus, Magnaporthe grisea

Efficient regulation of nitrogen metabolism likely plays a role in the ability of fungi to exploit ecological niches. To learn about regulation of nitrogen metabolism in the rice blast pathogen Magnaporthe grisea, we undertook a genome-wide analysis of gene expression under nitrogen-limiting conditions. Five hundred and twenty genes showed increased transcript levels at 12 and 48 h after shifting the fungus to media lacking nitrate as a nitrogen source. Thirty-nine of these genes have putative functions in amino acid metabolism and uptake, and include the global nitrogen regulator in M. grisea, NUT1. Evaluation of seven nitrogen starvation-induced genes revealed that all were expressed during rice infection. Targeted gene replacement on one such gene, the vacuolar serine protease, SPM1, resulted in decreased sporulation and appressorial development as well as a greatly attenuated ability to cause disease. Data are discussed in the context of nitrogen metabolism under starvation conditions, as well as conditions potentially encountered during invasive growth in planta.

Molecular epidemiology of norovirus strains circulating in Ireland from 2003 to 2004

Since 2002, the burden of norovirus (NoV) infection in Ireland has increased. Outbreaks in institutional settings are the most common causing widespread disruption to health service delivery. This is the first national study of NoV in the Republic of Ireland and its aim was to identify the major NoV strains circulating in Ireland over a 13-month period between November 2003 and November 2004, inclusive. A prospective study screened faecal samples (n = 478) for NoV RNA. Positive samples (n = 116) were further analysed by a second PCR, targeted to the orf1/orf2 junction of the virus. Phylogenetic analysis was based on sequence alignments of this domain. GII/4 viruses represented 92.2% of sequences, 2.7% were GII/2, GII/3 and GGIIB cluster-like strains. The remaining 5.2% were of GI origin. NoV was detectable throughout the study period, although two peaks of infection were observed. The majority of infections were caused by a range of closely related GII/4 NoV strains.

Hepatitis C viral clearance in an intravenous drug-using cohort in the Dublin area

BACKGROUND

The rate of spontaneous HCV viral clearance is reported as 20-25% but recent data indicate a higher frequency in some cohorts. The rate of spontaneous clearance in intravenous drug users has not been reported in an Irish setting.

AIMS

To determine the rate of spontaneous hepatitis C viral clearance and genotype in an Irish intravenous drug-using cohort.

METHODS

Drug users attending five drug treatment clinics in the Dublin were investigated. Data were prospectively recorded from January 1997 to June 2001 and follow-up testing completed in 2003. There were 496 HCV antibody positive patients identified and assessed for HCV RNA clearance. All were HIV and hepatitis B negative, 68.8% were male.

RESULTS

HCV RNA negativity (viral clearance) was documented in 38% of patients. Viral clearance was 47.4% in females and 34.5% in males (p = 000.6). Clearance was independent of age or duration of intravenous drug use. Viral clearance as defined as two negative consecutive HCV RNA tests, a minimum of one year apart, was sustained in 82.2% at two-year follow-up, giving an overall viral clearance of 31.1%. HCV genotype 1 and 3 were most commonly identified at 48.8% and 48.5% respectively in those with chronic infection.

CONCLUSIONS

Spontaneous HCV viral clearance occurs at a higher frequency than previously reported. Genotype 1 and 3 are commonest in the patient cohort.

Contribution of an aspartate residue, D114, in the active site of clostridial glutamate dehydrogenase to the enzyme's unusual pH dependence

Glutamate dehydrogenase from Clostridium symbiosum displays unusual kinetic behaviour at high pH when compared with other members of this enzyme family. Structural and sequence comparisons with GDHs from other organisms have indicated that the Asp residue at position 114 in the clostridial enzyme may account for these differences. By replacing this residue by Asn, a mutant protein has been created with altered functional properties at high pH. This mutant protein can be efficiently overexpressed in Escherichia coli, and several criteria, including mobility in non-denaturing electrophoresis, circular dichroism (CD) spectra and initial crystallisation studies, suggest a folding and an assembly comparable to those of the wild-type protein. The D114N mutant enzyme shows a higher optimum pH for activity than the wild-type enzyme, and both CD data and activity measurements show that the distinctive time-dependent reversible conformational inactivation seen at high pH in the wild-type enzyme is abolished in the mutant.

In situ localization and in vitro induction of plant COPI-coated vesicles

Coat protein (COP)-coated vesicles have been shown to mediate protein transport through early steps of the secretory pathway in yeast and mammalian cells. Here, we attempt to elucidate their role in vesicular trafficking of plant cells, using a combined biochemical and ultrastructural approach. Immunogold labeling of cryosections revealed that COPI proteins are localized to microvesicles surrounding or budding from the Golgi apparatus. COPI-coated buds primarily reside on the cis-face of the Golgi stack. In addition, COPI and Arf1p show predominant labeling of the cis-Golgi stack, gradually diminishing toward the trans-Golgi stack. In vitro COPI-coated vesicle induction experiments demonstrated that Arf1p as well as coatomer could be recruited from cauliflower cytosol onto mixed endoplasmic reticulum (ER)/Golgi membranes. Binding of Arf1p and coatomer is inhibited by brefeldin A, underlining the specificity of the recruitment mechanism. In vitro vesicle budding was confirmed by identification of COPI-coated vesicles through immunogold negative staining in a fraction purified from isopycnic sucrose gradient centrifugation. Similar in vitro induction experiments with tobacco ER/Golgi membranes prepared from transgenic plants overproducing barley alpha-amylase-HDEL yielded a COPI-coated vesicle fraction that contained alpha-amylase as well as calreticulin.

In situ localization and in vitro induction of plant COPI-coated vesicles

Coat protein (COP)-coated vesicles have been shown to mediate protein transport through early steps of the secretory pathway in yeast and mammalian cells. Here, we attempt to elucidate their role in vesicular trafficking of plant cells, using a combined biochemical and ultrastructural approach. Immunogold labeling of cryosections revealed that COPI proteins are localized to microvesicles surrounding or budding from the Golgi apparatus. COPI-coated buds primarily reside on the cis-face of the Golgi stack. In addition, COPI and Arf1p show predominant labeling of the cis-Golgi stack, gradually diminishing toward the trans-Golgi stack. In vitro COPI-coated vesicle induction experiments demonstrated that Arf1p as well as coatomer could be recruited from cauliflower cytosol onto mixed endoplasmic reticulum (ER)/Golgi membranes. Binding of Arf1p and coatomer is inhibited by brefeldin A, underlining the specificity of the recruitment mechanism. In vitro vesicle budding was confirmed by identification of COPI-coated vesicles through immunogold negative staining in a fraction purified from isopycnic sucrose gradient centrifugation. Similar in vitro induction experiments with tobacco ER/Golgi membranes prepared from transgenic plants overproducing barley alpha-amylase-HDEL yielded a COPI-coated vesicle fraction that contained alpha-amylase as well as calreticulin.

Nurses' knowledge, experiences, and attitudes concerning living wills

A random sample of 974 registered nurses in Nova Scotia were surveyed during the 1995-96 registration year to determine their understanding of living wills legislation; their experiences, roles, and attitudes related to living wills; and their perceptions of the barriers to and resources for using living wills in their practice. Responses from 157 nurses indicated that they were unfamiliar with the Medical Consent Act, the Hospitals Act, and the Powers of Attorney Act. Although they revealed that they had a positive attitude towards living wills, and they identified nurses as the appropriate health professional to initiate discussions about living wills with patients, very few had any actual experience in this role. Respondents rated their understanding of living wills as low, and many indicated that they were uncomfortable discussing the topic with clients. Respondents saw both the individual nurse and the practice environment as barriers to the use of living wills, and they clearly indicated the need for interdisciplinary educational strategies to facilitate the use of living wills in their nursing practice.

Enhanced proliferation of CD4+ T cells induced by dendritic cells following antigen uptake in the presence of specific antibody

Afferent lymph dendritic cells bear an Fc gamma receptor which binds antigen/antibody complexes thereby enhancing uptake of antigen. In this report, we have addressed the question of whether the enhanced uptake of antigen results in augmented antigen presentation and T cell proliferation in in vitro secondary responses in sheep. Inclusion of affinity-purified IgG anti-ovalbumin antibody in cultures of afferent lymph dendritic cells, purified CD4+ T cells, and substimulating amounts of ovalbumin resulted in a five- to 169-fold enhancement of T cell proliferation. This effect was antigen-specific as replacement of the anti-ovalbumin antibody with an IgG anti-human serum albumin specific antibody did not cause enhanced T cell responses. The antigen-specific augmentation required intact antibody Fc portions as F(ab')2 fragments of the anti-ovalbumin antibodies were ineffective. The enhanced antigen presentation was found to be maximal with immune complexes in moderate antibody excess (three- to 30-fold), but still occurred at antibody/antigen ratios of 300. The augmented responses were inhibitable with anti-MHC Class II specific antibodies, indicating that at least some of the antigen taken in via Fc gamma receptors entered a Class II processing pathway. The results thus show that antigen uptake via Fc gamma receptors on dendritic cells results in functional augmentation of antigen presentation and T cell proliferation.

A dipeptidylpeptidase secreted by Fasciola hepatica

A dipeptidylpeptidase (DPP) was isolated from Fasciola hepatica by gel-filtration and ion-exchange chromatography. The exoproteinase is secreted by newly excysted juveniles, immature and mature flukes. The liver fluke DPP is a serine proteinase of molecular weight > 200 kDa and differs from previously characterized mammalian DPPs in its substrate preference and susceptibility to inactivation by inhibitors. The parasite DPP may function in the latter stages of the proteolytic digestion of host macromolecules. In this manner, the enzyme may be important in providing the parasite with dipeptides that could be absorbed through the intestine as nutrient.

Further enzymatic characteristics of a thylakoid protein kinase

The enzymatic characteristics of a protein kinase purified from thylakoids are further described. ATP (KM approximately 30 microM) and Mg2+ ion (greater than 1.0 mM) were required for activity, while ADP was a competitive inhibitor (Ki = 100 microM). Activity was 55% inhibited by the sulfhydryl inhibitor p-chloromercuribenzoate (1 mM) and was less sensitive to substituted maleimides. Lysine-rich histones (H1) were utilized as an exogenous phosphorylation substrate both by thylakoid-bound kinase and by isolated enzyme; threonine was predominantly phosphorylated by the in situ enzyme, whereas the isolated enzyme phosphorylated closely related serine residues as determined by peptide mapping. Detergents that proved useful in extracting the kinase from thylakoids markedly inhibited activity of the isolated enzyme, whereas Triton X-100 and 3-[(3-cholamidopropyl)dimethylammonio]-1-propane-sulfonic acid had little effect. The enzyme could be freed from detergent and behaved as an active monomer on size-exclusion chromatography. The phosphate contents of the light-harvesting chlorophyll a/b protein complex of photosystem II isolated from maximally phosphorylated thylakoid membranes of spinach and pea were equivalent to approximately 6% and approximately 19% phosphorylation, respectively. Corresponding values for nonphosphorylated membranes were approximately 3% and approximately 14.5%.

Phosphorylation of thylakoid proteins by a purified kinase

A simplified method is given for the purification of a 64-kilodalton protein kinase from spinach or pea thylakoid membranes (Coughlan, S., and Hind, G. (1986) J. Biol. Chem. 261, 11378-11385). In a heterogeneous reconstitution system comprised of purified kinase and washed thylakoids (having their intrinsic kinase inactivated or removed), endogenous light-harvesting pigment protein of photosystem II could serve as a substrate. Its phosphorylation did not require rebinding of kinase to the thylakoid membrane and, like the phosphorylation of solubilized pigment protein, was not under redox control. No reconstitution was observed upon replacing 64-kilodalton protein kinase with 25-kilodalton protein kinase (Coughlan, S., and Hind, G. (1986) J. Biol. Chem. 261, 14062-14068). Tryptic digestion of phosphorylated membranes removed the site of phosphorylation; the phosphorylated amino acid present in light-harvesting pigment protein and its tryptic peptide was threonine. Immunoglobulin from a polyclonal antiserum, raised against the purified enzyme, fully inhibited kinase activity toward solubilized and endogenous pigment protein. At higher titers, the antibody was effective in totally inhibiting the redox-sensitive phosphorylation of thylakoid proteins by endogenous kinase; inhibition profiles for phosphorylation of pigment protein and thylakoid proteins of 32, 16, and 9 kilodaltons were essentially identical. The 64-kilodalton protein kinase would thus appear to be responsible for all of the observed phosphorylation of thylakoid phosphoproteins.

The ferredoxin-NADP+ oxidoreductase-binding protein is not the 17-kDa component of the cytochrome b/f complex

The complex between ferredoxin-NADP+ oxidoreductase and its proposed membrane-binding protein (Vallejos, R. H., Ceccarelli, E., and Chan, R. (1984) J. Biol. Chem. 259, 8048-8051) was isolated from spinach thylakoids and compared with isolated cytochrome b/f complex containing associated ferredoxin NADP+ oxidoreductase (Clark, R. D., and Hind, G. (1983) J. Biol. Chem. 258, 10348-10354). There was no immunological cross-reactivity between the 17.5-kDa binding protein and an antiserum raised against the 17-kDa polypeptide of the cytochrome complex. Association of ferredoxin-NADP+ oxidoreductase with the binding protein or with the thylakoid membrane gave an allotopic shift in the pH profile of diaphorase activity, as compared to the free enzyme. This effect was not seen in enzyme associated with the cytochrome b/f complex. Identification of the 17.5-kDa binding protein as the 17-kDa component of the cytochrome b/f complex is ruled out by these results.