Binding of different antigen-enzyme and antibody-enzyme conjugates by intracellular antibodies in cytoplasm and Golgi complex of plasma cells

Summary Intracellular immunoglobulins in plasma cells were characterized by antigen-enzyme conjugates and anti-immunoglobulin antibody-enzyme conjugates applied in a double immunocytochemical approach. After their assemblage, immunoglobulins in the cytoplasm of anti-TNP antibody producing plasma cells can be demonstrated both by TNP-enzyme conjugates and by anti-immunoglobulin ( or chain specific) antibody-enzyme conjugates. Once arrived in the Golgi complex (GC) detection with TNP-enzyme conjugates remains possible, but anti-immunoglobulin antibody-enzyme conjugates did not bind to a detectable degree. Similar results were obtained in experiments where immunoglobulin-enzyme conjugates were used both as an antigen-enzyme conjugate and as an antibody-enzyme conjugate.     

Avidin-HRP conjugates in biotin-avidin immunoenzyme cytochemistry

Avidin-HRP conjugates were prepared, analysed and tested for avidin-biotin immunocytochemistry. Suitable biotinylation of enzymes, antigens and antibody was obtained by reacting biotin at equimolar ratio to epsilon aminogroups in proteins. The avidin-biotin interaction was used for immunocytochemical detection of phenomena in the field of immunology, i.e. immune complex trapping, specific antibody forming cells and in serology for the cytochemical detection of human auto-antibodies to basement membrane components. Avidin-HRP conjugation using the two step glutaraldehyde method gave a very small amount of monomeric, low molecular weight conjugate with excellent performance. Avidin-HRP conjugation using the periodate method was modified at two points. The first modification concerns the molar ratio of avidin to HRP in the reaction mixture which was brought to about equimolarity. The second modification concerns the periodate concentration which was decreased five fold, ten fold and twenty fold. Decreasing the periodate concentration decreased the amount of polymeric conjugate. Optimal amounts of monomeric, low molecular weight conjugate were obtained with a ten fold decrease of the periodate concentration. Comparable cytochemical results were obtained with monomeric conjugates obtained using both preparation methods.     

Avidin-HRP conjugates in biotin-avidin immunoenzyme cytochemistry

Summary Avidin-HRP conjugates were prepared, analysed and tested for avidin-biotin immunocytochemistry. Suitable biotinylation of enzymes, antigens and antibody was obtained by reacting biotin at equimolar ratio to epsilon aminogroups in proteins. The avidin-biotin interaction was used for immunocytochemical detection of phenomena in the field of immunology, i.e. immune complex trapping, specific antibody forming cells and in serology for the cytochemical detection of human auto-antibodies to basement membrane components. Avidin-HRP conjugation using the two step glutaraldehyde method gave a very small amount of monomeric, low molecular weight conjugate with excellent performance. Avidin-HRP conjugation using the periodate method was modified at two points. The first modification concerns the molar ratio of avidin to HRP in the reaction mixture which was brought to about equimolarity. The second modification concerns the periodate concentration which was decreased five fold, ten fold and twenty fold. Decreasing the periodate concentration decreased the amount of polymeric conjugate. Optimal amounts of monomeric, low molecular weight conjugate were obtained with a ten fold decrease of the periodate concentration. Comparable cytochemical results were obtained with monomeric conjugates obtained using both preparation methods.In honour of Professor P. van Duijn     

Zinc stabilizes the SecB binding site of SecA

The molecular chaperone SecB targets preproteins to SecA at the translocation sites in the cytoplasmic membrane of Escherichia coli. SecA recognizes SecB via its carboxyl-terminal 22 aminoacyl residues, a highly conserved domain that contains 3 cysteines and 1 histidine residue that could potentially be involved in the coordination of a metal ion. Treatment of SecA with a zinc chelator resulted in a loss of the stimulatory effect of SecB on the SecA translocation ATPase activity, while the activity could be restored by the addition of ZnCl2. Interaction of SecB with the SecB binding domain of SecA is disrupted by chelators of divalent cations, and could be restored by the addition of Cu2+ or Zn2+. Atomic absorption and electrospray mass spectrometry revealed the presence of one zinc atom per monomeric carboxyl terminus of SecA. It is concluded that the SecB binding domain of SecA is stabilized by a zinc ion that promotes the functional binding of SecB to SecA.     

A temperature-regulated replicon-based DNA expression system

We present a temperature-regulated, alphavirus replicon-based DNA expression system. The system is regulated by a viral temperature-sensitive RNA-dependent RNA replicase, creating a temperature-dependent RNA amplification loop. Because of this positive feedback, the system exhibits both low background and high inducibility. We observed 700-fold induction in transiently transfected cells, and over 104-fold induction in stably transfected cells. The high stringency of inducibility allowed the generation of stable cell lines expressing a highly toxic protein upon temperature shift. These data suggest that the present expression system could simplify bioprocess engineering strategies, especially in situations where the cloned protein has detrimental effects on host cell metabolism.     

Effects of multidisciplinary integrated care on quality of care in residential care facilities for elderly people: a cluster randomized trial

Background:

Sophisticated approaches are needed to improve the quality of care for elderly people living in residential care facilities. We determined the effects of multidisciplinary integrated care on the quality of care and quality of life for elderly people in residential care facilities.

Methods:

We performed a cluster randomized controlled trial involving 10 residential care facilities in the Netherlands that included 340 participating residents with physical or cognitive disabilities. Five of the facilities applied multidisciplinary integrated care, and five provided usual care. The intervention, inspired by the disease management model, consisted of a geriatric assessment of functional health every three months. The assessment included use of the Long-term Care Facility version of the Resident Assessment Instrument by trained nurse-assistants to guide the design of an individualized care plan; discussion of outcomes and care priorities with the family physician, the resident and his or her family; and monthly multidisciplinary meetings with the nurse-assistant, family physician, psychologist and geriatrician to discuss residents with complex needs. The primary outcome was the sum score of 32 risk-adjusted quality-of-care indicators.

Results:

Compared with the facilities that provided usual care, the intervention facilities had a significantly higher sum score of the 32 quality-of-care indicators (mean difference − 6.7, p = 0.009; a medium effect size of 0.72). They also had significantly higher scores for 11 of the 32 indicators of good care in the areas of communication, delirium, behaviour, continence, pain and use of antipsychotic agents.

Interpretation:

Multidisciplinary integrated care resulted in improved quality of care for elderly people in residential care facilities compared with usual care.

Trial registration:

www.controlled-trials.com trial register no. ISRCTN11076857.The quality of care provided in residential care facilities is under pressure worldwide.¹ Facilities are frequently understaffed, and the complexity of care needed by residents increases while expertise of staff does not necessarily keep pace.^2,3 Although most care organizations want to innovate and improve quality of care, many lack expertise or financial resources needed to do so.^4,5 Family physicians are responsible for medical care in residential care facilities in the Netherlands. However, they do not regard themselves as suited for systematic management of chronic diseases and disabilities associated with frail health.⁶About 10% of elderly people aged 75 or older in the Netherlands live in residential care facilities.^7,8 These facilities were established to offer sheltered living for elderly people who are disabled but still relatively healthy. Because of the growing elderly population, the characteristics of elderly people living in residential care facilities have become more comparable to those of people in nursing homes, who need complex care. Residential care facilities in the Netherlands are comparable to residential care facilities in Canada, are publicly funded and are subject to government inspection and approval. Over 70% of the residents need professional care, such as assistance with activities of daily living, nursing care (e.g., medication, wound care) and housekeeping. They have multiple chronic diseases and associated disabilities.^9–12Effective interventions for chronic illnesses generally rely on a multidisciplinary team approach. The elements of this approach include structured geriatric assessment, protocol-based regulation of medications, support for self-reliance and intensive follow-up. The closely related disease management model comprises coordination of care, steering of the care process and patient empowerment.¹³ This model is strongly recommended by Bodenheimer and colleagues to improve the health and quality of life of chronically ill patients.¹⁴ However, no studies have as yet been undertaken to evaluate the effects of disease management on functional health and quality of care for elderly people in residential care facilities who have physical or cognitive disabilities.We developed an approach to multidisciplinary integrated care inspired by the disease management model. The objective of our study was to determine the effects of multidisciplinary integrated care on quality of care and quality of life for elderly people in residential care facilities.     

Au sujet de la fermentation du glucose parPl. Tetani

Résumé et conclusions Les recherches deTasman etPondman confirment et amplifient les n?tres. La souche 132 fait fermenter 100% de glucose et donne des variantes qui ne font plus fermenter le glucose comme toutes les souches dePl. tetani, qui ont été étudiées avant eux et sous cet angle. Les filaments longs etGram-négatifs qu'ils ont pris pour une contamination sont des cadavres de bactéries dont la population est arrivée à la phase de mortalité logarithmique.     

Plasmodium berghei: gametocyte production, DNA content, and chromosome-size polymorphisms during asexual multiplication in vivo

In this study the DNA content and the karyotype of clones of Plasmodium berghei, which differed in the capability to produce gametocytes, were determined. The DNA content per haploid genome was established by cytofluorometric methods after staining of the haploid merozoites with DNA-specific fluorescent dyes. Field inversion gel electrophoresis was used to establish the number and size of the chromosomes. Parasites of a high gametocyte producer clone (original HP) and a low producer clone (original LP) contained 13 to 14 chromosomes in the size range of 0.5-3.8 megabase. In four independent experiments parasites of the original HP clone were maintained in mice and were mechanically transmitted for prolonged periods of time (up to 90 weeks). During the transmission period the capability to produce gametocytes decreased in all four lines. After mosquito transmission of parasites from these low producer lines, the gametocyte production returned to the level of the original HP clone. The total DNA content per haploid genome of low producer parasites was not significantly different from that of HP parasites. During prolonged periods of asexual multiplication of the HP clone in vivo, changes in the relative size of several chromosomes were detected. Mosquito transmission of the original HP clone did not result in a change of the karyotype. However, novel karyotypes were readily observed after mosquito transmission of parasites of the low producer lines. The decrease of the capability to produce gametocytes did not necessarily involve detectable changes in DNA content or in karyotype.