Cytokine expression in feline osteoclastic resorptive lesions

Feline osteoclastic resorptive lesions (FORL) of the teeth are common in cats, and lead to pain, destruction of the periodontal ligament, and tooth loss. The expression of interleukin (IL)-1 beta and IL-6 mRNA was higher in teeth with FORL than in normal teeth (P<0.01 and P<0.001, respectively), but no such differences were found between pathological and normal gingival tissue samples. There were no differences between teeth affected with FORL and normal teeth in respect of the expression of receptor activator of NF kappa B ligand (RANKL) mRNA or osteoprotegerin (OPG) mRNA. However, OPG mRNA expression was higher in gingival tissue associated with teeth affected with FORL than in normal gingival tissue (P<0.05), whereas the reverse was true of RANKL mRNA expression (P<0.05). OPG mRNA expression was significantly higher in teeth than in femoral and alveolar bone (P<0.001). RANKL and OPG mRNAs were detected in all tissues examined. The data suggest that the elevated expression of IL-l beta and IL-6 mRNA plays a role in the mediation of osteoclast activity in advanced FORL. In contrast, OPG and RANKL do not appear to regulate osteoclasts in advanced disease. The results also suggest that OPG and RANKL mRNA play a role in mediating inflammatory responses in gingival cells, and that OPG has an inhibiting effect on tooth resorption.

Selective and signal-dependent recruitment of membrane proteins to secretory granules formed by heterologously expressed von Willebrand factor

von Willebrand factor (vWF) is a large, multimeric protein secreted by endothelial cells and involved in hemostasis. When expressed in AtT-20 cells, vWF leads to the de novo formation of cigar-shaped organelles similar in appearance to the Weibel-Palade bodies of endothelial cells in which vWF is normally stored before regulated secretion. The membranes of this vWF-induced organelle, termed the pseudogranule, are uncharacterized. We have examined the ability of these pseudogranules, which we show are secretagogue responsive, to recruit membrane proteins. Coexpression experiments show that the Weibel-Palade body proteins P-selectin and CD63, as well as the secretory organelle membrane proteins vesicle-associated membrane protein-2 and synaptotagmin I are diverted away from the endogenous adrenocorticotropic hormone-containing secretory granules to the vWF-containing pseudogranules. However, transferrin receptor, lysosomal-associated membrane protein 1, and sialyl transferase are not recruited. The recruitment of P-selectin is dependent on a tyrosine-based motif within its cytoplasmic domain. Our data show that vWF pseudogranules specifically recruit a subset of membrane proteins, and that in a process explicitly driven by the pseudogranule content (i.e., vWF), the active recruitment of at least one component of the pseudogranule membrane (i.e., P-selectin) is dependent on residues of P-selectin that are cytosolic and therefore unable to directly interact with vWF.

Coagulation changes in individuals with sickle cell trait

Sickle cell disorders, such as Hb SS and Hb SC, are associated with a hypercoagulable state that may contribute to the vaso-occlusive episodes observed in the disorders. To what extent increased coagulation activity occurs in individuals with sickle cell trait has had limited study. Because such information may help clarify clinical and pathologic findings that may occur in these individuals and may be useful in clarifying the hypercoagulable state in sickle cell disease, we have examined individuals with Hb AS to determine the extent that increased coagulation activity does occur. We measured d-dimers, thrombin-antithrombin (TAT) complexes, prothrombin fragment 1.2 (F1.2), absolute blood monocyte levels, proteins C and S, and isotypes of antiphospholipid antibodies in individuals with Hb AS and in matched controls (Hb AA). Results showed that d-dimers, TAT, and F1.2 were increased significantly above normal levels. Absolute blood monocyte levels were increased. The d-dimers, TAT, F1.2, and monocyte counts showed significant increasing trends through groups of increasing severity (Hb AA, Hb AS, Hb SC, and Hb SS). Our study shows that individuals with Hb AS have increased coagulation activity, with d-dimers, TAT, and F1.2 being consistent indicators. The measures of coagulation activity in Hb AS are lower than in patients with Hb SC and Hb SS disease. These results extend our previous observation that the degree of coagulation activation parallels the degree of disease severity among sickle cell genotypes. The findings suggest that monocytosis, with the possible expression of monocyte-derived tissue factor, and the associated hypercoagulable state are driven by disease severity.

A kinetic microassay for glutathione in cells plated on 96-well microtiter plates

We describe a modified enzymatic, kinetic, glutathione microassay based on the original macroassay described by Tietze and modified by Anderson. It is coupled with the Triton X-100 lysis and an acid extraction that can be performed in 96-well microtiter plates. The microassay can be read in a microplate reader equipped with a standard 405 nm filter. Intracellular glutathione levels are not significantly different when comparing the proposed Triton X-100 lysis and acid extraction method from those found with the cellular homogenization and acid extraction method typically employed. By combining a rapid sample extraction method, which can be done on the microtiter plate, with an assay based on the technology of a microplate reader, we have devised a rapid, reproducible, inexpensive and easy to use GSH microassay that can process several hundred samples daily and will be useful in studies where many replicate samples are required. We have successfully used this method to monitor glutathione status in a human cell line exposed to organochlorine pesticides and cells exposed to naturally occurring mixtures of metals extracted from aquatic sediments.

Short report: codon 125 polymorphism of CD31 and susceptibility to malaria

Platelet-endothelial cell adhesion molecule 1 (PECAM-1/CD31) has been identified as an endothelial cell receptor of Plasmodium falciparum-infected erythrocytes. The significance of adhesion of infected erythrocytes to this receptor in malaria infection has not been determined. We have therefore studied the association of the functional mutation CTG-->GTG (Leu-->Val) in codon 125 of the Cd31 gene with severe disease in 2 case-control studies of malaria in Madang Hospital, Papua New Guinea, and in Kilifi District Hospital, Kenya. We analyzed data from 442 cases and controls from Papua New Guinea and data from 396 cases and controls from Kenya. The codon 125 polymorphism was not associated with severe malaria in either study. We conclude that the presence of CTG-->GTG (Leu-->Val) substitution in codon 125 in CD31 is not associated with protection from severe malaria, and we suggest that selective forces other than malaria may maintain this high-frequency polymorphism.

Single capacitive discharge utilizing an auxiliary shock in the coronary venous system reduces the defibrillation threshold

Auxiliary shocks (AS) from electrodes sutured to the left ventricle (LV) prior to primary biphasic shocks (PS) have been shown to reduce defibrillation thresholds (DFT). Two capacitors are required to generate these waveforms. We investigate delivery of AS from one capacitor using a novel waveform. The epicardial surface of the LV is accessed transvenously via the middle cardiac vein (MCV) avoiding a thoracotomy.

METHODS

A defibrillation electrode was placed in the right ventricle (RV) and superior vena cava (SVC) in 12 pigs (37+/-2 kg). A 50x1.8 mm electrode was inserted in the MCV through a guide catheter. A can was placed in the left pectoral region. A monophasic AS (100 microF, 1.5 J) was delivered along one pathway before switching to deliver a biphasic waveform (40% tilt, 2 ms phase 2) along another. DFTs (PS+AS) were assessed using a binary search. Two configurations not incorporating AS acted as controls. DFTs were compared using repeated measures analysis of variance.

RESULTS

DFTs of the four novel configurations (AS/PS) were: RV-->Can/MCV-->Can=14.9+/-3.7 J, MCV-->Can/RV-->Can=17.2+/-5.7 J, RV-->SVC+Can/MCV-->SVC+Can=13.4+/-4.6 J, MCV-->SVC+Can/RV-->SVC+Can=17.1+/-5.9 J. Delivering AS in the RV followed by PS in the MCV reduced the DFT (RV-->Can (19.9+/-7.3 J, P<0.01) and RV-->SVC+Can (19.2+/-6.0 J, P<0.05)).

CONCLUSIONS

Delivering AS prior to PS in the MCV reduces the DFT by up to a third compared to conventional configurations of RV-->Can and RV-->SVC+Can. This is possible using only a single capacitor and an entirely transvenous approach to the LV.

Pre-operative electrocardiograph examination

The leading cause of death following surgery is a cardiac event, and an electrocardiogram is the most common pre-operative test to investigate coronary artery disease. Fifty adults, who required an electrocardiogram, undergoing general surgical procedures, were recruited into this pilot study, which investigated the examination rate of electrocardiographs by doctors pre-operatively. Each tracing was folded in one corner and a paperclip prevented full pre-operative viewing without its removal. Results suggest that 30% of ECGs were not opened and the records of 58% patients overall had no mention of the ECG having been performed. Further analysis showed no correlation with the examination rate of the electrocardiograph with patient age or fitness. If this reflects normal clinical practice, it is sub-optimal use of resources and warrants further audit.

Overexpression of connexin 43 in skeletal myoblasts: Relevance to cell transplantation to the heart

OBJECTIVE

Skeletal myoblast transplantation is a promising strategy for treating end-stage heart failure. One potential problem in the development of functional, synchronously contracting grafts is the degree of intercellular communication between grafted myoblasts and host cardiomyocytes. Thus it is expected that enhancement of intercellular gap junction formation would result in improved efficiency of skeletal myoblast transplantation. In this study we investigated whether myoblasts overexpressing connexin 43, a major cardiac gap junction protein, would enhance this intercellular communication.

METHODS AND RESULTS

L6 rat skeletal myoblast cell lines overexpressing connexin 43 were generated by means of gene transfection and clonal selection. Connexin 43 overexpression of these myoblasts, which continued both in undifferentiated and differentiated states (up to 17-fold greater protein level in comparison with control-transfected myoblasts, as measured with Western blotting), was observed on cell surfaces where gap junctions should exist. Both dye microinjection and scrape loading with fluorescent dyes showed enhancement in intercellular dye transfer between connexin 43-transfected myoblasts compared with that found in control-transfected cells. Morphologically, these myoblasts fused and differentiated into multinucleated myotubes more rapidly, demonstrating a higher level of cellular creatine kinase activity as a marker of myogenic differentiation throughout the culture period compared with that of control-transfected myoblasts.

CONCLUSIONS

We have generated connexin 43-overexpressing skeletal myoblast cell lines that resulted in improved formation of functional intercellular gap junctions, which could be relevant to synchronous contraction of grafted myoblasts in the heart. In addition, these cells demonstrated more rapid differentiation, which would also be advantageous in a graft for transplantation to the heart.

Investigation of microcontact transfer of proteins from a selectively plasma treated elastomer stamp by fluorescence microscopy and force microscopy

Selective plasma treatment of the recessed regions of the elastomer stamps is shown to alter the resultant protein patterns. Fluorescence microscopy is demonstrated to be an excellent tool to discriminate between regions of microcontact printed fluorescent dye-labelled albumin in polystyrene. Atomic force microscopy and shear force microscopy are used to provide high-resolution images of the patterned protein layers. The formation and characteristics of the patterns formed by these alternative strategies is discussed.

Prediction of mortality by exercise echocardiography: a strategy for combination with the duke treadmill score

BACKGROUND

In studies generally involving short follow-up, exercise echocardiography has been shown to predict composite end points. We sought to study the prediction of mortality with this test and to devise a strategy for combination with standard exercise testing.

METHODS AND RESULTS

Clinical, exercise testing, and echocardiographic data were collected in 5375 patients (aged 54+/-14 years, 3880 men) undergoing exercise echocardiography. The Duke treadmill score was derived from the results of treadmill exercise testing. Resting left ventricular (LV) function and the presence and severity of ischemia were interpreted by expert observers. Follow-up at 10.6 years (mean 5.5+/-1.9 years) was complete in 5211 patients (97%). The Duke score classified 59% of patients as low risk, 39% as intermediate risk, and 2% as high risk. Resting LV dysfunction was present in 1445 patients (27%), and the exercise echocardiogram was abnormal in 2525 patients (47%). Death occurred in 649 patients (12%). Over the first 6 years of follow-up, those with normal exercise echocardiograms had a mortality of 1% per year. Ischemia was an independent predictor of mortality. In sequential Cox models, the predictive power of clinical data was strengthened by adding the Duke score, resting LV function, and the results of exercise echocardiography. Exercise echocardiography was able to substratify patients with intermediate-risk Duke scores into groups with a yearly mortality of 2% to 7%.

CONCLUSIONS

A normal exercise echocardiogram confers a low risk of death, and positive results are an independent predictor of death; ischemia is incremental to other data. This test may be particularly useful in patients with intermediate-risk Duke treadmill scores.

Adenosine- and verapamil-sensitive ventricular tachycardia in the newborn

Two neonates presented with sustained, monomorphic VT. Transesophageal electrophysiological studies demonstrated that the VTs were initiated with burst atrial pacing in one and noninducible in the other, and both terminated with burst atrial pacing and with adenosine. Oral verapamil suppressed the VTs in both. Following discontinuation of verapamil at 1 year of age, both children remain free of tachycardia recurrence at 3 and 4 years of age. These cases suggest that cAMP-mediated triggered activity may be responsible for some VTs in infancy.

A normal sonogram does not exclude malrotation

We present case reports of three recent patients to reinforce the argument that upper gastrointestinal series is the method of choice with which to document malrotation. It has been 9 years since there was a major discussion of this subject in the literature. Ultrasonography cannot confidently exclude malrotation. Radiographic study with contrast continues to be the best diagnostic tool.

Developing an integrated nursing team approach

Nursing Standard recently published a literature search that explored different models of integrated nursing and more traditional models of community nursing in primary care (Baileff 2000). Models of change for implementing integrated nursing were also examined. This article aims to explore the development of an integrated nursing team in a healthcare centre in Northampton.

Sexual practices of HIV discordant and concordant couples in Rwanda: effects of a testing and counselling programme for men

As part of a longitudinal investigation, the husbands and cohabiting male partners of 684 Rwandan women were recruited to participate in an HIV testing and counselling programme. All of the women and 256 of the men (37%) had previously received standard testing and generic counselling services. In this project, all of the men participated in an extensive, male-focused counselling programme. This included 428 men who were receiving testing and counselling for the first time. Interview responses indicated that rates of condom use during sexual intercourse increased dramatically at the one-year follow-up assessment for the serodiscordant couples. This effect was especially strong for couples whose male partners were receiving testing and counselling for the first time. Rates of condom use also increased substantially in seroconcordant HIV-positive couples whose partners had both been tested previously. Women in couples with at least one seropositive partner reported lower rates of coercive sex by their male partners after they completed the counselling programme. Male-focused and couple-focused testing and counselling programmes appear to be effective in reducing risky sexual behaviours in heterosexual couples, even if one or both partners have received testing and counselling services previously.

Novel alleles at the lymphotoxin alpha (LTalpha) locus mark extended HLA haplotypes in native Africans

Genetic variations at the closely related tumor necrosis factor alpha (TNFalpha or TNF) and lymphotoxin alpha (LTalpha, formerly TNFbeta) loci have been well documented in various human populations, and several haplotypes spanning the MHC class I and class II loci are known to carry specific TNF alleles. Genotyping of the TNFc microsatellite within the first intron of LTalpha in 285 Rwandans and 319 Zambians revealed two predominant alleles, c1 at frequencies of 0.598 and 0.683 and c2 at 0.384 and 0.307, respectively. Overall, the distribution of TNFc genotypes containing the major alleles conformed well to the Hardy-Weinberg equilibrium in both cohorts. Two previously unrecognized minor TNFc alleles were also detected: the first, designated c0, was found in 10 native Africans and was the only allele present in 10 chimpanzees; the second, designated c3, was seen in 6 other African patients. Further genotyping at loci for HLA class I, class II, and for transporters associated with antigen processing, subunit 1 (TAP1) in those 16 individuals suggested a tight, stable extended haplotype involving c0 and 26Asn (LTalpha)-TNF3 (TNF promoter -238A and -308G)-DRB1*1503-DQB1*0602-TAP1.2 (333Val)-TAP1.4 (637Gly). The c3 allele was observed on another extended haplotype with 26Thr (LTalpha)-TNF1 (TNF promoter -238G and -308G)-DQB1*0102-DQB1*0501-TAP1*0101 (333Ile and 637Asp). The c3-tagged haplotype further extended to Cw*15 at the HLA class I C locus, but no specific A or B alleles could be unambiguously assigned. Positive associations between c2 homozygosity and HIV-1 seronegative status in both Rwandans and Zambians (odds ratio = 2.03 and 2.00, p = 0.04 and 0.07, respectively) had little effect on the haplotype assignments. These findings suggest a preferential expansion of the human TNFc dinucleotide (CT/AG) repeat sequence and further imply the existence of two extended MHC lineages that have not been disrupted by recombinations.

Use of Hoechst 33342 staining to detect apoptotic changes in bovine mononuclear phagocytes infected with Mycobacterium avium subsp. paratuberculosis

Mycobacterium avium subsp. paratuberculosis is an intracellular pathogen of macrophages that causes a chronic enteritis (Johne's disease) in ruminants. The purpose of this study was to determine whether M. avium subsp. paratuberculosis infection causes apoptosis in bovine monocytes. Using Hoechst 33342 staining, we observed increased numbers of apoptotic monocytes within 6 h of infection with M. avium subsp. paratuberculosis, and these numbers increased further at 24 and 48 h. This effect appeared to require viable bacilli, because monocytes infected with heat-killed M. avium subsp. paratuberculosis did not exhibit a significant increase in apoptosis. Preincubation of monocytes with bovine growth hormone prior to infection with M. avium subsp. paratuberculosis did not significantly alter the number of apoptotic cells.

TAPI polymorphisms in several human ethnic groups: characteristics, evolution, and genotyping strategies

Genetic variations in the locus encoding the transporter associated with antigen processing, subunit 1 (TAP1), were systematically studied using samples from Caucasians, Africans, Brazilians, and compared with data from chimpanzees. PCR-amplified genomic sequences corresponding to the 11 exons were analyzed by single-strand conformation polymorphism (SSCP) and sequencing. Six nonsynonymous and 2 synonymous single nucleotide polymorphisms (SNPs) were found to be common in one ethnic group or another, and they involved codons 254 (Gly-GGC/Gly-GGT) in exon 3, 333 (Ile-ATC/Val-GTC) in exon 4, 370 (Ala-GCT/Val-GTT) in exon 5, 458 (Val-GTG/Leu-TTG) in exon 6, 518 (Val-GTC/Ile-ATC) in exon 7, 637 (Asp-GAC/Gly-GGC), 648 (Arg-CGA/Gln-CAA) and 661 (Pro-CCG/Pro-CCA) in exon 10. At each SNP site the sequence listed first was predominant in all ethnic groups. Several SNPs segregated on the same chromosome regardless of populations and species. Together, the SNPs produced 5 major human TAP1 alleles, 4 of which matched the officially recognized alleles *0101, *02011, *0301, and *0401; the 5th allele differed from each of those by at least 4 SNPs. Overall, TAP1*0101 was the predominant allele in all ethnic groups, with frequencies ranging from 0.667 in Zambians to 0.808 in US Caucasians. The TAP1*0401 frequency showed the greatest difference between Africans (0.221-0.254) and Caucasians (0.033), with Brazilians (0.058) fitting in the middle. Consistent with earlier work based on Caucasians and gorillas, *0101 appeared to be the newest human TAP1 allele, suggesting a dramatic spread of *0101 into all human populations examined. Characterization of TAP1 polymorphisms allowed the design of a PCR-based genotyping scheme that targeted 7 SNP sites and required 2 separate genotyping techniques.

Characteristics of HLA class I and class II polymorphisms in Rwandan women

OBJECTIVE

To define HLA class I and class II polymorphisms in Rwandans.

METHODS

PCR-based HLA genotyping techniques were used to resolve variants of HLA-A, B, and C to their 2- or 4-digit allelic specificities, and those of DRB1 and DQB1 to their 4- or 5-digit alleles.

RESULTS

Frequencies of 14 A, 8 C, and 14 B specificities and of 13 DRB1 and 8 DQB1 alleles were >/=0.02 in a group of 280 Rwandan women. These major HLA factors produced 6 haplotypes extending across the class I and class II regions: A*01-Cw*04-B* 4501-DRB1*1503-DQB1*0602 (A1-Cw4-B12- DR15 - DQ6), A * 01 - Cw * 04 - B * 4901 -DRB1 * 1302-DQB1*0604 (A1-Cw4-B21-DR13-DQ6), A*30 - Cw*04 - B*15 - DRB1*1101 - DQB1*0301 (A19-Cw4-B15-DR11-DQ7), A*68-Cw*07-B* 4901-DRB1*1302-DQB1*0604(A28-Cw7-B21- DR13 - DQ6), A*30 - Cw*07 - B*5703 - DRB1* 1303-DQB1*0301(A19 - Cw7 - B17 - DR13 - DQ7), and A*74-Cw*07-B*4901-DRB1*1302-DQB1* 0604 (A19-Cw7-B21-DR13-DQ6), respectively. Collectively, these extended haplotypes accounted for about 19% of the total. Other apparent class I-class II haplotypes (e.g., Cw*17-B*42-DRB1*0302-DQB1*0402, Cw*06- B*58-DRB1*1102-DQB1*0301, and Cw*03- B*15-DRB1*03011-DQB1*0201) did not extend to the telomeric HLA-A locus, and other 3-locus class I haplotypes (e.g., A*68-Cw*04-B*15, A*74-Cw*04-B*15, and A*23-Cw*07-B*4901) completely or partially failed to link with any specific class II alleles.

DISCUSSION

Frequent recombinations appeared to occur between the three evolutionarily conserved HLA blocks carrying the class I and class II loci. The HLA class I profile seen in Rwandans was not directly comparable with those known in the literature, although the class II profile appeared to resemble those in several African populations. These data provide additional evidence for the extensive genetic diversity in Africans.