Acute Reduction in Left Ventricular Function Following Transcatheter Mitral Edge-to-Edge Repair.

Background Little is known about the impact of transcatheter mitral valve edge-to-edge repair on changes in left ventricular ejection fraction (LVEF) and the effect of an acute reduction in LVEF on prognosis. We aimed to assess changes in LVEF after transcatheter mitral valve edge-to-edge repair for both primary and secondary mitral regurgitation (PMR and SMR, respectively), identify rates and predictors of LVEF reduction, and estimate its impact on prognosis. Methods and Results In this international multicenter registry, patients with both PMR and SMR undergoing transcatheter mitral valve edge-to-edge repair were included. We assessed rates of acute LVEF reduction (LVEFR), defined as an acute relative decrease of >15% in LVEF, its impact on all-cause mortality, major adverse cardiac event (composite end point of all-cause death, mitral valve surgery, and residual mitral regurgitation grade ≥2), and LVEF at 12 months, as well as predictors for LVEFR. Of 2534 patients included (727 with PMR, and 1807 with SMR), 469 (18.5%) developed LVEFR. Patients with PMR were older (79.0±9.2 versus 71.8±8.9 years; P<0.001) and had higher mean LVEF (54.8±14.0% versus 32.7±10.4%; P<0.001) at baseline. After 6 to 12 months (median, 9.9 months; interquartile range, 7.8-11.9 months), LVEF was significantly lower in patients with PMR (53.0% versus 56.0%; P<0.001) but not in patients with SMR. The 1-year mortality was higher in patients with PMR with LVEFR (16.9% versus 9.7%; P<0.001) but not in those with SMR (P=0.236). LVEF at baseline (odds ratio, 1.03 [95% CI, 1.01-1.05]; P=0.002) was predictive of LVEFR for patients with PMR, but not those with SMR (P=0.092). Conclusions Reduction in LVEF is not uncommon after transcatheter mitral valve edge-to-edge repair and is correlated with worsened prognosis in patients with PMR but not patients with SMR. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT05311163.

2-year outcomes of MitraClip as a bridge to heart transplantation: The international MitraBridge registry.

BACKGROUND: In the first report from the MitraBridge registry, MitraClip as a bridge to heart transplantation (HTx) proved to be at 1-year an effective treatment strategy for 119 patients with advanced heart failure (HF) who were potential candidates for HTx. We aimed to determine if benefits of MitraClip procedure as a bridge-to-transplant persist up to 2-years. METHODS: By the end of the enrollment period, a total of 153 advanced HF patients (median age 59 years, left ventricular ejection fraction 26.9 ± 7.7%) with significant secondary mitral regurgitation, who were potential candidates for HTx and were treated with MitraClip as a bridge-to-transplant strategy, were included in the MitraBridge registry. The primary endpoint was the 2-year composite adverse events rate of all-cause death, first hospitalization for HF, urgent HTx or LVAD implantation. RESULTS: Procedural success was achieved in 89.5% of cases. Thirty-day mortality was 0%. At 2-year, Kaplan-Meier estimates of freedom from primary endpoint was 47%. Through 24 months, the annualized rate of HF rehospitalization per patient-year was 44%. After an overall median follow-up time of 26 (9-52) months, elective HTx was successfully performed in 30 cases (21%), 19 patients (13.5%) maintained or obtained the eligibility for transplant, and 32 patients (22.5%) no longer had an indication for HTx because of significant clinical improvement. CONCLUSIONS: After 2-years of follow-up, the use of MitraClip as a bridge-to-transplant was confirmed as an effective strategy, allowing elective HTx or eligibility for transplant in one third of patients, and no more need for transplantation in 22.5% of cases.

Changes in demographics, treatment and outcomes in a consecutive cohort who underwent transcatheter aortic valve implantation between 2005 and 2020.

INTRODUCTION: Transcatheter aortic valve implantation (TAVI) has matured to the treatment of choice for most patients with aortic stenosis (AS). We sought to identify trends in patient and procedural characteristics, and clinical outcomes in all patients who underwent TAVI between 2005 and 2020. METHODS: A single-centre analysis was performed on 1500 consecutive patients who underwent TAVI, divided into three tertiles (T) of 500 patients treated between November 2005 and December 2014 (T1), January 2015 and May 2018 (T2) and June 2018 and April 2020 (T3). RESULTS: Over time, mean age and gender did not change (T1 to T3: 80, 80 and 79 years and 53%, 55% and 52% men, respectively), while the Society of Thoracic Surgeons risk score declined (T1: 4.5% to T3: 2.7%, p < 0.001). Use of general anaesthesia also declined over time (100%, 24% and 1% from T1 to T3) and transfemoral TAVI remained the default approach (87%, 94% and 92%). Median procedure time and contrast volume decreased significantly (186, 114 and 56 min and 120, 100 and 80 ml, respectively). Thirty-day mortality (7%, 4% and 2%), stroke (7%, 3% and 3%), need for a pacemaker (19%, 22% and 8%) and delirium (17%, 12% and 8%) improved significantly, while major bleeding/vascular complications did not change (both approximately 9%, 6% and 6%). One-year survival was 80%, 88% and 92%, respectively. CONCLUSION: Over our 15 years' experience, patient age remained unchanged but the patient risk profile became more favourable. Simplification of the TAVI procedure occurred in parallel with major improvement in outcomes and survival. Bleeding/vascular complications and the need for pacemaker implantation remain the Achilles' heel of TAVI.

Clinical consequences of consecutive self-expanding transcatheter heart valve iterations.

OBJECTIVE: To compare early clinical outcomes after transcatheter aortic valve implantation (TAVI) with three consecutive generations of self-expanding valves (SEVs). METHODS: Clinical endpoints of consecutive patients who underwent TAVI with CoreValve, Evolut R or Evolut PRO were included in a prospective database. RESULTS: TAVI was performed with CoreValve (n = 116), Evolut R (n = 160) or Evolut PRO (n = 92). Evolut R and Evolut PRO showed a tendency towards lower permanent pacemaker implantation (PPI) rates compared to CoreValve (CoreValve 27% vs Evolut R 16% vs Evolut PRO 18%, p = 0.091). By multivariable regression analysis CoreValve had a significantly higher risk for PPI (odds ratio (OR) 2.79, 95% confidence interval (CI) 1.31-5.94, p = 0.008) compared to Evolut R, while Evolut R and PRO were similar. Severe paravalvular leakage (PVL) occurred only with CoreValve, but no significant difference was observed in moderate PVL (10% vs 8% vs 6%, p = 0.49). CoreValve had a tendency towards a higher risk for more-than-mild PVL as compared with the Evolut platform (R + PRO) (OR 2.46, 95% CI 0.98-6.16, p = 0.055). No significant differences in all-cause mortality (7% vs 4% vs 1%, p = 0.10), stroke (6% vs 3% vs 2%, p = 0.21) or major vascular complications (10% vs 12% vs 4%, p = 0.14) were observed. CONCLUSIONS: TAVI with self-expanding valves was safe, and device iterations may result in a lower need for PPI. More-than-mild PVL seemed to occur less often with repositionable technology.

Transcatheter mitral valve repair in proportionate and disproportionate functional mitral regurgitation-insights from a small cohort study.

BACKGROUND: Functional mitral regurgitation (FMR) can be subclassified based on its proportionality relative to left ventricular function and end-diastolic volume. FMR proportionality could help identify responders to transcatheter edge-to-edge mitral valve repair (MitraClip) in terms of residual FMR and/or clinical improvement. METHODS: This single-centre retrospective cohort study evaluated the feasibility of determining FMR proportionality in symptomatic heart failure patients with reduced left ventricular function who were treated with MitraClip for ≥ moderate-to-severe FMR. Baseline proportionate (pFMR) and disproportionate FMR (dFMR) were distinguished. Patient characteristics and MitraClip procedural outcomes were described. RESULTS: From an overall cohort of 81 eligible FMR patients, 23/81 (28%) had to be excluded due to missing transthoracic echocardiogram parameters, 22/81 were excluded based on FMR severity. The remaining cohort, of 36/81 patients (44%), could be classified into dFMR (n = 26) or pFMR (n = 10). Conduction disorders were numerically increased in dFMR. All cases requiring > 2 clips were in the dFMR group and absence of FMR reduction occurred more frequently with dFMR. POINT OF VIEW/CONCLUSION: Important limitations in terms of imaging acquisition affect the translation of the FMR proportionality concept to a real-world data set. We did observe different demographic and FMR response patterns in patients with proportionate and disproportionate FMR that warrant further investigation.

MitraClip in secondary mitral regurgitation as a bridge to heart transplantation: 1-year outcomes from the International MitraBridge Registry.

BACKGROUND: Patients awaiting heart transplantation (HTx) often need bridging therapies to reduce worsening and progression of underlying disease. Limited data are available regarding the use of the MitraClip procedure in secondary mitral regurgitation for this clinical condition. METHODS: We evaluated an international, multicenter (17 centers) registry including 119 patients (median age: 58 years) with moderate-to-severe or severe secondary mitral regurgitation and advanced heart failure (HF) (median left ventricular ejection fraction: 26%) treated with MitraClip as a bridge strategy according to 1 of the following criteria: (1) patients active on HTx list (in list group) (n = 31); (2) patients suitable for HTx but awaiting clinical decision (bridge to decision group) (n = 54); or (3) patients not yet suitable for HTx because of potentially reversible relative contraindications (bridge to candidacy group) (n = 34). RESULTS: Procedural success was achieved in 87.5% of cases, and 30-day survival was 100%. At 1 year, Kaplan-Meier estimates of freedom from the composite primary end-point (death, urgent HTx or left ventricular assist device implantation, first rehospitalization for HF) was 64%. At the time of last available follow-up (median: 532 days), 15% of patients underwent elective transplant, 15.5% remained or could be included in the HTx waiting list, and 23.5% had no more indication to HTx because of clinical improvement. CONCLUSIONS: MitraClip procedure as a bridge strategy to HTx in patients with advanced HF with significant mitral regurgitation was safe, and two thirds of patients remained free from adverse events at 1 year. These findings should be considered exploratory and hypothesis-generating to guide further study for percutaneous intervention in high-risk patients with advanced HF.

Activity-based matrix metallo-protease enrichment using automated, inhibitor affinity extractions.

An automated inhibitor affinity extraction method for the activity-based enrichment of matrix metallo-proteases (MMPs) is presented. Samples containing purified MMP-12 were first extracted at different flow rates in a syringe pump setup, using cartridges packed with an MMP inhibitor affinity sorbent based on an immobilized hydroxamic acid containing peptide (PLG-NHOH) with mumol/L MMP affinity. Faster extractions, a reduced number of manual manipulations, and higher extraction yields (98.9%-99.3%) were obtained over the whole flow rate range compared to batch extractions. Application of the method to synovial fluid from a rheumatoid arthritis patient followed by gelatin-zymography revealed a strong enrichment of distinct MMPs from this biological sample that were not clearly visible in the original sample. The use of an auto-sampler and a solid-phase extraction (SPE) workstation allowed full automation of the extraction procedure with the potential for on-line coupling to further sample preparation and analytical steps. MMP-12 extractions were optimized showing that ligand density is an important factor with a clear extraction yield optimum around 5 to 7.5 mmol/L. Conditioning of the stationary phase for 1 week prior to use resulted in a further slight increase in extraction yield. Under optimal conditions, an extraction yield of 99.5% was reached with a cartridge contact time of only 13 s for MMP-12. The efficacy of the extraction method for activity-based MMP profiling was further improved by the use of a broad-spectrum MMP inhibitor with nmol/L affinity (TAPI-2). This resulted in an increased extraction yield for all tested MMPs. For MMP-1, -7, -8, -10, -12, and -13 extraction yields of at least 98.8% were obtained, while for MMP-9 (full length and catalytic domain) an extraction yield of at least 96.1% was reached.

Clinical experience with the N-shaped ileal neobladder: assessment of complications, voiding patterns, and quality of life in our series of 58 patients.

PURPOSE: The purpose of this retrospective study was to assess complications, voiding patterns, and quality of life in patients with an orthotopic bladder substitution, using an N-shaped ileal neobladder. MATERIALS AND METHODS: Between May 1996 and December 2002, 58 patients (52 men and 6 women) underwent an orthotopic ileal neobladder reconstruction after radical cystectomy. The mean age was 47 for the female and 60 for the male patients. In all patients an N-shaped ileal pouch was constructed. This pouch has not yet been described in the literature before. All procedures were performed by the same surgeon (HVP) and the mean follow-up was 38 months. Complications were registered as early (occurring within 3 months) or late (occurring after 3 months), and as pouch-related and non-pouch-related. The patients took part in a pelvic floor re-education programme for as long as they were incontinent. All patients completed a retrospective Quality of Life questionnaire, based on the QLQ-C30 questionnaire, which was validated by the EORTC's Study Group on Quality of Life. RESULTS: In 38% of the patients, early complications occurred, whereas 48% had late complications. The most frequent early complications were diarrhea (24%) and pyelonephritis (9%). Diarrhea was again the most frequently mentioned non-pouch-related complication (19%). The most frequently observed pouch-related late complication was ileo-urethral stenosis. This occurred in five patients. All of these 5 patients were re-operated using a minimally invasive approach. Daytime continence was achieved in 95% of patients and nighttime continence in 66%. Hyper-continence with subsequent need for CISC was observed in 5 out of 6 women (83%) and 0 out of 52 men (0%). The retrospective QoL questionnaire learned that the impact of bladder removal and orthotopic bladder substitution has acceptable impact on patient's everyday life. Diarrhea was mentioned as being the most discomforting complication by most of the patients. CONCLUSIONS: We describe a modified orthotopic ileal neobladder: the ileal N-pouch. The functional results with this pouch are good. Complication rates and QoL are comparable with the larger series published by other authors, using different ileal neobladder reconstructions.

Vaccination with plasmid DNA encoding mycobacterial antigen 85A stimulates a CD4+ and CD8+ T-cell epitopic repertoire broader than that stimulated by Mycobacterium tuberculosis H37Rv infection.

Vaccination of mice with plasmid DNA carrying the gene for the major secreted mycobacterial antigen 85A (Ag85A) from Mycobacterium tuberculosis is a powerful technique for generating robust specific Thl helper T-cell responses, CD8+-mediated cytotoxicity, and protection against M. tuberculosis challenge (K. Huygen et al., Nat. Med. 2:893-898, 1996). We have now analyzed in more detail the antigen-specific immune CD4+- and CD8+-T-cell responses induced in BALB/c mice vaccinated with Ag85A DNA and have compared these responses to those generated by intravenous infection with M. tuberculosis. T-cell-epitope mapping, as measured by interleukin-2 and gamma interferon secretion from splenic T cells restimulated in vitro with synthetic 20-mer peptides spanning the complete mature sequence of Ag85A, demonstrated that DNA vaccination stimulated a stronger and broader T-cell response than did M. tuberculosis infection. Moreover, elevated cytotoxic T lymphocyte (CTL) activity against Ag85A-transfected and peptide-pulsed P815 target cells could be generated exclusively by vaccination with plasmid DNA, not following M. tuberculosis infection. By using DNA vaccination, three Ag85A CTL epitopes with predicted major histocompatibility complex class I binding motifs were defined. One of them was previously reported as a dominant, promiscuously recognized T-cell epitope in healthy humans with primary infections. These data strengthen the potential of DNA vaccination with respect to inducing antituberculous immunity in humans.

Cloning of the antigen 85A from Mycobacterium gordonae and its use for the specific PCR identification of these mycobacteria.

The complete nucleotide sequence of 85A antigen of Mycobacterium gordonae was determined. This gene encodes 339 amino acids, including 43 amino acids for the signal peptide, followed by a mature protein of 296 amino acids. A polymerase chain reaction (PCR) assay for the rapid detection of M. gordonae DNA using two pairs of oligonucleotide primers, derived from our sequence, is described. This one-step PCR has been used successfully to amplify 38 strains of M. gordonae. Conversely, the primers did not amplify DNA from any of the 25 mycobacterial species tested. The results suggest that this PCR assay could be a good alternative to existing commercial assays for the specific identification of M. gordonae on early culture on solid medium or on early BACTEC broth culture.

Three different putative phosphate transport receptors are encoded by the Mycobacterium tuberculosis genome and are present at the surface of Mycobacterium bovis BCG.

A gene encoding a protein homologous to the periplasmic ABC phosphate binding receptor PstS from Escherichia coli was cloned and sequenced from a lambda gt11 library of Mycobacterium tuberculosis by screening with monoclonal antibody 2A1-2. Its degree of similarity to the E. coli PstS is comparable to those of the previously described M. tuberculosis phosphate binding protein pab (Ag78, Ag5, or 38-kDa protein) and another M. tuberculosis protein which we identified recently. We suggest that the three M. tuberculosis proteins share a similar function and could be named PstS-1, PstS-2, and PstS-3, respectively. Molecular modeling of their three-dimensional structures using the structure of the E. coli PstS as a template and their inducibility by phosphate starvation support this view. Recombinant PstS-2 and PstS-3 were produced and purified by affinity chromatography. With PstS-1, these proteins were used to demonstrate the specificity of three groups of monoclonal antibodies. Using these antibodies in flow cytometry and immunoblotting analyses, we demonstrate that the three genes are expressed and their protein products are present and accessible at the mycobacterial surface as well as in its culture filtrate. Together with the M. tuberculosis genes encoding homologs of the PstA, PstB, and PstC components we cloned before, the present data suggest that at least one, and possibly several, related and functional ABC phosphate transporters exist in mycobacteria. It is hypothesized that the mycobacterial gene duplications presented here may be a subtle adaptation of intracellular pathogens to phosphate starvation in their alternating growth environments.

A Mycobacterium tuberculosis gene cluster encoding proteins of a phosphate transporter homologous to the Escherichia coli Pst system.

We report the cloning and sequencing of three M. tuberculosis genes encoding proteins homologous to E. coli PstA, PstC and PstB. They are tentatively called pstA-2, pstC-1 and pstB. They encode proteins of 302, 336 and 275 amino acids, respectively. In E. coli, PstB is the ATP binding component and PstA/PstC are the two hydrophobic subunits of a phosphate permease belonging to the family of ABC (ATP-binding cassette) transporters. In mycobacteria, PstS-1, the phosphate binding subunit (Andersen and Hansen, 1989), is encoded by a gene directly surrounded by pstB, pstC-1 and pstA-2 within a potential operon (pstB, pstS-1, pstC-1, pstA-2). Phosphate uptake by whole, suspension grown, M. bovis BCG cells was measured and could be inhibited by a monoclonal antibody directed against the PstS-1 subunit, suggesting that these genes encode subunits of a functional mycobacterial phosphate permease.

Identification of a second Mycobacterium tuberculosis gene cluster encoding proteins of an ABC phosphate transporter.

Following the identification of a M. tuberculosis phosphate transporter belonging to the superfamily of ABC transporters, we report on the cloning and sequencing of two additional genes, called pstS-3 and pstC-2, encoding proteins homologous to PstS and PstC of Escherichia coli, respectively. Together with the previously isolated M. tuberculosis gene similar to the E. coli pstA, these are included in a cluster encoding a second putative phosphate transport system. We demonstrate that pstS-3 encodes the previously described Ag 88, a 40 kDa M. bovis BCG culture filtrate antigen (immunodominant in H-2b haplotype type mice). Finally, a signature motif identifying integral transmembrane proteins of prokaryotic phosphate binding-dependent permeases is proposed.

In vitro NCp7 enhancement of ribozyme-mediated cleavage of full-length human IL-6 mRNA.

We have previously shown that a ribozyme directed against human interleukin-6 (IL-6) mRNA is efficient in vivo, despite its poor activity in vitro on full-length IL-6 mRNA. We compared the effect of the nucleocapsid protein of HIV-1 (NCp7) on the ribozyme cleavage reaction of a long (1041 nt) and a short (19 nt) substrate IL-6 RNA in vitro. At a one to five molar ratio of the long substrate to ribozyme, almost no cleavage is observed after 30 min at 37 degrees C. The NCp7 protein significantly increases the catalytic activity of the ribozyme on this substrate (from 0 to 53% after 7 min at 37 degrees C), but not on the short one. A kinetic analysis of single turnover reactions performed with ribozyme in at least fivefold molar excess over substrate also lead to a stimulation (70-fold) of the reaction rate with long substrate, but not with the shorter one. Preferential increases of the catalytic activity on the long substrate suggests that the NCp7 protein prevents misfolding of RNAs.

Mutagenesis of the human interleukin-6 fourth predicted alpha-helix: involvement of the Arg168 in the binding site.

Random substitutions of amino acid 161-184 of human interleukin-6 (hIL-6) have been generated at the cDNA level using oligonucleotide-directed mutagenesis. Among the majority of the mutant proteins showing a reduced biological activity on murine hybridoma cells, only those having a substitution of Met161, Arg168, Arg179 or Met184, retained a tertiary structure similar to the IL-6 folding. These residues are thus probably involved in the interaction with the IL-6 receptor. However, the contacts established by Arg168 and Arg179 seem far more important for the biological activity. According to Bazan's model of cytokine folding and the receptor binding site on the fourth alpha-helix, based on growth hormone similarity, we propose that Arg168 and Arg179 are located on the exposed surface of this presumed helix.

Structure of the Mycobacterium tuberculosis antigen 88, a protein related to the Escherichia coli PstA periplasmic phosphate permease subunit.

We report the cloning and sequencing of the gene coding for antigen 88 from Mycobacterium tuberculosis by using monoclonal antibodies to screen an expression library in lambda gt11. The gene encodes a 403-amino-acid-residue protein with a calculated molecular mass of 43,790 Da which contains seven putative transmembrane alpha-helical domains and presents a significant homology to the PstA protein of Escherichia coli. In its N-terminal region, it contains a 61-amino-acid region highly homologous to the fifth transmembrane helix of E. coli PstC. PstA and PstC are the two hydrophobic subunits of an E. coli periplasmic phosphate permease. Since the phosphate-binding subunit of this putative permease in M. tuberculosis has previously been characterized, i.e., the 38-kDa mycobacterial protein (also called protein antigen b, Ag 5, and Ag 78) homologous to PstS of E. coli, it seems likely that functional permeases analogous to the periplasmic permeases of gram-negative bacteria also exist in mycobacteria.

The genes coding for the antigen 85 complexes of Mycobacterium tuberculosis and Mycobacterium bovis BCG are members of a gene family: cloning, sequence determination, and genomic organization of the gene coding for antigen 85-C of M. tuberculosis.

A gene encoding the 33-kDa secreted protein of Mycobacterium tuberculosis (antigen 85-C) was isolated and sequenced. The corresponding DNA sequence contains a 1,020-bp coding region. The deduced amino acid sequence corresponds to a 340-residue protein consisting of a 46-amino-acid signal peptide and a 294-amino-acid mature protein. Comparison with previously described genes for the 30-kDa antigen (the alpha antigen of M. bovis BCG, also called antigen 85-B) and the 32-kDa antigens from M. bovis BCG and M. tuberculosis (antigens 85-A) indicates that the three genes share considerable sequence homology (70.8 to 77.5%) but may also code for distinctive epitopes. Strong differences among the three sequences are clearly visible upstream and downstream from the region coding for the mature proteins. The three genes have been detected in the genome of M. bovis BCG by Southern blot hybridization with three type-specific probes. Furthermore, hybridization of large DNA fragments (100 to 1,000 kbp) from M. tuberculosis separated by pulsed-field gel electrophoresis showed that the three genes coding for the antigen 85 complex are not clustered within the bacterial genome.

Cloning, sequence determination, and expression of a 32-kilodalton-protein gene of Mycobacterium tuberculosis.

We describe the identification of the gene encoding an immunodominant 32-kilodalton (kDa) protein of Mycobacterium tuberculosis. The 32-kDa antigen is abundantly secreted into the culture supernatant of a variety of mycobacteria and appears to be a major stimulant of cellular and humoral immunity against mycobacteria. Recombinant clones expressing a 140- or 125-kDa beta-galactosidase fusion protein reactive with rabbit polyclonal anti-32 kDa protein serum were detected. The corresponding DNA sequence contains a 1,008-base-pair coding region. The deduced amino acid sequence corresponds to a 336-residue protein including the previously determined NH2-terminal sequence of the 32-kDa protein (J. De Bruyn, K. Huygen, R. Bosmans, M. Fauville, R. Lippens, J. P. Van Vooren, P. Falmagne, M. Weckx, H. G. Wiker, M. Harboe, and M. Turneer, Microb. Pathog. 2:351-366, 1987). Upstream of this NH2-terminal region, the gene codes for a signal peptide required for the secretion of a 294-amino-acid-long mature protein. A putative promoter sequence could be located upstream of the open reading frame. Comparison of the M. tuberculosis 32-kDa antigen with the Mycobacterium bovis BCG alpha-antigen (K. Matsuo, R. Yamaguchi, A. Yamazaki, H. Tasaka, and T. Yamada, J. Bacteriol. 170:3847-3854, 1988) revealed 73.8% homology between DNA sequences and 72.8% homology between amino acid sequences (signal and mature protein). Finally, the 140-kDa fusion protein could selectively be recognized by human tuberculous sera. This result confirms our previous finding that the 32-kDa antigen could be a valuable tool for the serological diagnosis of tuberculosis. Moreover, the availability of recombinant proteins opens perspectives for the localization of relevant B- and T-cell epitope regions on the 32-kDa antigen.

Evidence for an electrogenic and a non-electrogenic component in the slow phase of the P515 response in chloroplasts.

The flash-induced P515 absorbance change in intact chloroplasts consists of a fast and a slow phase. There is disagreement in the literature over the origin of the slow phase. Here we argue that the flash-induced slow phase in P515 absorbance change is composed of two different components. One component is most probably due to the electrogenic Q-cycle associated with the cytochrome b/f complex. The second component has decay kinetics that are much slower than the electrogenic reactions. We suggest that the second component is due to a non-electrogenic reaction.