Cost of Thoracotomy Approach: An Analysis of the LATERAL Trial.

BACKGROUND: Less invasive techniques for left ventricular assist device implantation have been increasingly prevalent over past years and have been associated with improved clinical outcomes. The procedural economic impact of these techniques remains unknown. We sought to study and report economic outcomes associated with the thoracotomy implantation approach. METHODS: The LATERAL clinical trial evaluated the safety and efficacy of the thoracotomy approach for implantation of the HeartWare centrifugal-flow ventricular assist device system (HVAD). We collected UB-04 forms in parallel to the trial, allowing analysis of index hospitalization costs. All charges were converted to costs using hospital-specific cost-to-charge ratios and were subsequently compared with Medicare cost data for the same period (2015-2016). Because thoracotomy implants were off-label for all left ventricular assist devices during that period, the Medicare cohort was assumed to consist predominately of traditional sternotomy patients. RESULTS: Thoracotomy patients demonstrated decreased costs compared with sternotomy patients during the index hospitalization. Mean total index hospitalization costs for thoracotomy were $204,107 per patient, corresponding to 21.6% reduction (P < .001) and $56,385 savings per procedure compared with sternotomy. Across almost all cost categories, thoracotomy implants were less costly. CONCLUSIONS: In LATERAL, a clinical trial evaluating the safety and efficacy of the thoracotomy approach for HVAD, costs were lower than those reported in Medicare patient claims occurring over the same period. Because Medicare data can be presumed to consist of predominately sternotomy procedures, thoracotomy appears less expensive than traditional sternotomy.

Evaluation of a lateral thoracotomy implant approach for a centrifugal-flow left ventricular assist device: The LATERAL clinical trial.

BACKGROUND: The HeartWare centrifugal-flow ventricular assist device system (HVAD) is a viable option for treatment of advanced heart failure. There is a growing trend toward the use of less invasive techniques in cardiac surgery, and the thoracotomy technique for HVAD implantation may provide benefits not available with conventional approaches. METHODS: The LATERAL trial is a multicenter, prospective, non-randomized, single-arm trial that utilized data from 144 patients enrolled in the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) database at 26 centers in the United States and Canada. The primary composite end-point was success at 180 days defined as alive on the originally implanted device and free from disabling stroke (modified Rankin Scale score >3), transplanted or explanted for recovery. The key secondary end-point was mean length of initial hospital stay. RESULTS: The primary end-point was successfully achieved in 88.1% of patients and was significantly greater than the pre-defined performance goal of 77.5% set from historical sternotomy data (p = 0.0012). The key secondary end-point-mean length of initial hospital stay -was 18 days and was significantly shorter than the pre-defined performance goal of 26.1 days obtained from historical sternotomy data (p < 0.0001). The adverse event profile further demonstrated the safety of the thoracotomy approach. The overall patient survival was good, and bleeding requiring reoperation was significantly less frequent than that observed in previous studies using the sternotomy approach. CONCLUSIONS: This prospective clinical trial provides validation that implantation of the HVAD system via the thoracotomy approach used in the LATERAL study represents a safe and effective alternative to median sternotomy in selected patients intended for a bridge-to-transplant indication.

Contribution of Cardiac Implantable Electronic Devices to Thrombus Formation in Patients With Chronic Thromboembolic Pulmonary Hypertension.

OBJECTIVES: This study aimed to identify the prevalence of cardiac implantable electronic devices (CIEDs) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) and to describe the associated disease burden. BACKGROUND: CTEPH is a debilitating disease, now potentially curable with pulmonary thromboendarterectomy (PTE). The contribution of CIEDs to thrombosis in this patient population has not been previously studied. METHODS: The charts of 982 CTEPH patients, who underwent PTE between January 1, 2009, and December 31, 2015 at University of California-San Diego (UCSD) Medical Center, were reviewed for pacemakers or implantable cardioverter defibrillators (ICDs) implanted before surgery. RESULTS: Among 982 CTEPH patients who underwent PTE, 14 had pacemakers and 3 had ICDs, giving 17 CIEDs and a prevalence of 1.7%. Of these 17 CIEDs, 6 devices were extracted intraoperatively, and 5 of 6 devices were replaced with epicardial leads. Furthermore, of the 950 patients classified by intraoperative UCSD level, 12 of 17 (70.6%) patients with CIEDs had distal disease versus 241 of 933 (25.8%) patients without CIEDs (p = 0.0002). The prevalence of known venous thromboembolism (VTE) was 50% in CIED patients compared with 78.6% in patients without CIEDs (p = 0.018). CONCLUSIONS: At 1.7%, the prevalence of CIEDs in the PTE population was higher than previously reported values, which estimated CIED prevalence between 0.16% and 0.47% in the general population. Moreover, CTEPH patients with CIEDs were more strongly associated with distal disease burden and less likely to have had previous VTE, which suggested that CIEDs may be a nidus for small clots that embolize distally in the pulmonary vasculature.

Chronic Thromboembolic Pulmonary Hypertension.

Chronic thromboembolic pulmonary hypertension occurs when acute thromboemboli fail to dissolve completely. The resulting fibrotic scar tissue within the pulmonary arteries is obstructive and eventually leads to right heart failure. Medical therapy for this condition is supportive, but surgery with pulmonary artery endarterectomy is curative, and carries a low mortality at experienced centers.

The Clostridium difficile problem: a South African tertiary institution's prospective perspective.

BACKGROUND AND OBJECTIVES: The aim of this study is to report the incidence of Clostridium difficile-associated disease (CDAD) in a tertiary-care hospital in South Africa and to identify risk factors, assess patient outcomes and determine the impact of the hypervirulent strain of the organism referred to as North American pulsed-field type 1 (NAP1). METHODS: Adults who presented with diarrhoea over a period of 15 months were prospectively evaluated for CDAD using stool toxin enzyme immunoassay (EIA). Positive specimens were evaluated by PCR. Patient demographics, laboratory parameters and outcomes were analysed. RESULTS: CDAD was diagnosed in 59 (9.2%) of 643 patients (median age 39 years, IQR 30 - 55). Thirty-four (58%) were female. Recent antibiotic exposure was reported in 39 (66%), 27 (46%) had been hospitalised within 3 months, and 14 (24%) had concomitant inflammatory bowel disease (IBD). Nineteen (32%) had community-acquired CDAD (CA-CDAD). The annual incidence of hospital-acquired CDAD (HA-CDAD) was 8.7 cases/10 000 hospitalisations. Two cases of the hypervirulent strain NAP1 were identified. Seven (12%) patients underwent colectomy (OR 6.83; 95% CI 2.41 - 19.3). On logistic regression, only antibiotic exposure independently predicted for CDAD (OR 2.9; 95% CI 1.6 - 5.1). Three (16%) cases of CA-CDAD reported antibiotic exposure (v. 90% of HA-CDAD, p<0.0001). Twelve (86%) patients had concomitant IBD (p<0.0001 v. HA-CDAD). CA-CDAD was significantly associated with antibiotic exposure (OR 0.04, 95% CI 0.01 - 0.24) and IBD (OR 9.6, 95% CI 1.15 - 79.8). CONCLUSION: The incidence of HA-CDAD in the South African setting is far lower than that reported in the West. While antibiotic use was a major risk factor for HA-CDAD, CA-CDAD was not associated with antibiotic therapy. Concurrent IBD was a predictor of CA-CDAD.

Hematological profile of East African short-horn zebu calves from birth to 51 weeks of age.

This paper is the first attempt to accurately describe the hematological parameters for any African breed of cattle, by capturing the changes in these parameters over the first 12 months of an animal's life using a population-based sample of calves reared under field conditions and natural disease challenge. Using a longitudinal study design, a stratified clustered random sample of newborn calves was recruited into the IDEAL study and monitored at 5-weekly intervals until 51 weeks of age. The blood cell analysis performed at each visit included: packed cell volume; red cell count; red cell distribution width; mean corpuscular volume; mean corpuscular hemoglobin concentration; hemoglobin concentration; white cell count; absolute lymphocyte, eosinophil, monocyte, and neutrophil counts; platelet count; mean platelet volume; and total serum protein. The most significant age-related change in the red cell parameters was a rise in red cell count and hemoglobin concentration during the neonatal period. This is in contrast to what is reported for other ruminants, including European cattle breeds where the neonatal period is marked by a fall in the red cell parameters. There is a need to establish breed-specific reference ranges for blood parameters for indigenous cattle breeds. The possible role of the postnatal rise in the red cell parameters in the adaptability to environmental constraints and innate disease resistance warrants further research into the dynamics of blood cell parameters of these breeds.

Telomerase activity and survival of late-stage South African esophageal carcinoma patients.

Squamous cell carcinoma of the esophagus is a cancer with a high incidence in South Africa. We have investigated the prognostic value of telomerase activity in tumors as well as nearby normal tissue. Biopsies from 98 patients (71 men and 27 women) were analyzed using an adaptation of the TRAP assay. We found all tumor biopsies to have moderate to high telomerase activity, while one third of biopsies from normal mucosa were negative. The telomerase activity level of the tumors had no prognostic value (P = 0.95) as determined by the log rank test. A P-value of 0.02 was found when the telomerase-negative and moderately positive normal biopsies were grouped together and compared to those with high activity. Our results show that telomerase activity of normal mucosa in the vicinity of the tumor can identify a population of patients with significantly worse prognosis, even in late stage patients.

The breed prevalence of dog erythrocyte antigen 1.1 in the Onderstepoort area of South Africa and its significance in selection of canine blood donors.

The blood group antigen Dog Erythrocyte Antigen (DEA) 1.1 is clinically the most important canine blood group as DEA 1.1 antibodies are capable of causing acute haemolytic, potentially life-threatening transfusion reactions. Dogs do not have naturally occurring antibodies to DEA 1.1 but are rapidly sensitised by the first incompatible transfusion. The prevalence of DEA 1.1 in the general dog population is estimated at 42-46%. Canine blood donors registered with the Onderstepoort Animal Blood Bank (n = 93) as well as potential donors (n = 140) were typed for DEA 1.1 using a monoclonal antibody card kit. All dogs came from the Onderstepoort area, near Pretoria, Gauteng province, South Africa. Overall prevalence of DEA 1.1 was 47%. Prevalence was 47% in purebred dogs and 48% in mongrels. Distinct breed differences were noted with less than 20% of German shepherd dogs and Boxers and greater than 75% of Rottweilers, Great Danes, St Bernards and Dalmations testing DEA 1.1 positive. Knowledge of local breed differences will increase effectiveness of blood donor recruitment.

PLATSAK, a potent antithrombotic and fibrinolytic protein, inhibits arterial and venous thrombosis in a baboon model.

Antiplatelet-antithrombin-staphylokinase (PLATSAK) is a chimeric protein that was recombinantly produced in Escherichia coli cells. The protein was designed to target haemostasis at three different levels. It consists of staphylokinase for activation of fibrinolyis, the Arg-Gly-Asp sequence for the prevention of platelet aggregation, and an antithrombotic peptide for the inhibition of thrombin. The in vivo activity of PLATSAK was evaluated by assessing its effect on platelet deposition in a baboon model of arterial and venous thrombosis. Dacron vascular graft segments and expansion chambers, inserted as extensions into permanent femoral arteriovenous shunts, were used to simulate arterial and venous thrombosis, respectively. PLATSAK (3.68 mg/kg) was administered as a bolus 10 minutes before placement of the thrombogenic devices. Platelet deposition onto the graft surface and in the expansion chamber was imaged in real time with a scintillation camera as the deposition of 111In-labeled platelets. After 2 hours, platelet deposition in the graft segments and expansion chambers was inhibited by 50% and 85%, respectively, when compared to control studies. The activated partial thromboplastin time was lengthened to greater than 120 seconds. Interestingly, the level of fibrinogen degradation products in plasma did not increase after administration of PLATSAK. These results demonstrate that PLATSAK effectively inhibited platelet deposition in both arterial- and venous-type thrombosis in an animal model.

Thiamine repression and pyruvate decarboxylase autoregulation independently control the expression of the Saccharomyces cerevisiae PDC5 gene.

The Saccharomyces cerevisiae gene PDC5 encodes the minor isoform of pyruvate decarboxylase (Pdc). In this work we show that expression of PDC5 but not that of PDC1, which encodes the major isoform, is repressed by thiamine. Hence, under thiamine limitation both PDC1 and PDC5 are expressed. PDC5 also becomes strongly expressed in a pdc1delta mutant. Two-dimensional gel electrophoresis of whole protein extracts shows that thiamine limitation stimulates the production of THI gene products and of Pdc5p. Deletion of PDC1 only stimulates production of Pdc5p. We conclude that the stimulation of PDC5 expression in a pdc1delta mutant is not due to a response to thiamine limitation.

Screening for gynecologic cancer.

Screening for cancer of the uterus, cervix, and ovary allows earlier detection of disease in some asymptomatic women. The screening tests commonly used have low false-negative rates and, with the exception of endometrial biopsy and endometrial washings in detection of uterine cancer, they have high false-positive rates. Conclusions concerning effectiveness of screening tests in improving the likelihood of a favorable outcome are difficult because there are no randomized trials. Without randomized trials, cost-benefit analysis of screening for gynecologic malignancies is imprecise.

A Saccharomyces cerevisiae mutant defective in the kinesin-like protein Kar3 is sensitive to NaCl-stress.

Several mutants of Saccharomyces cerevisiae showing poor growth in the presence of elevated concentrations of NaCl were isolated to identify genes involved in the osmo-stress response. One of these mutants (WAY.5-4A-11; osr11) which showed a clear 2:2 segregation of the salt-stress phenotype upon tetrad analysis when crossed to a wild-type strain has been characterised. The mutation responsible for poor growth under salt-stress was recessive. The corresponding gene was cloned by complementation of the mutant phenotype and a 3.5-kb fragment was isolated. The sequence of this fragment matched that of KAR3, a gene previously identified to be involved in karyogamy and mitosis. Allelism of OSR11 to KAR3 was confirmed by tetrad analysis, and disruption mutants showed the same NaCl-phenotype as the original osr11 mutation. The disruption mutant was more sensitive to high sucrose concentrations than the original mutant was to high glucose concentrations. In a different genetic background (W303-1A), the kar3 disruptants were less sensitive to osmo-stress than the WAY.5-4A strain. Heat-stress, nitrogen-starvation and cultivation on ethanol failed to affect the growth of osr11 and kar3 mutants, pointing to a possible specific involvement of KAR3 in the osmotic-stress response. Microscopic studies showed that cell division of the kar3 mutants was impaired and NaCl-stress conditions aggravated the phenotype.

Production of a recombinant antithrombotic and fibrinolytic protein, PLATSAK, in Escherichia coli.

The three main components involved in thrombosis and haemostasis are thrombin, platelets, and plasmin. Almost all inhibitors of thrombosis are focused either on the inhibition of thrombin or on the inhibition of platelets. We designed a construct using the fibrinolytic activity of staphylokinase, fused via a cleavable linker to an antithrombotic peptide of 29 amino acids. The peptide was designed to include three inhibitory regions: (1) the Arg-Gly-Asp (RGD) amino acid sequence to prevent fibrinogen binding to platelets; (2) a part of fibrinopeptide A, an inhibitor of thrombin; and (3) the tail of hirudin, a potent direct antithrombin. The amino acid sequence of the 29 amino acid peptide was reverse translated, and the gene was chemically synthesised and cloned into an expression vector as a 3' fusion to the staphylokinase gene. Gene expression was induced in E. coli Top 10 cells and the fusion protein, designated PLATSAK, was purified using metal affinity chromatography. The purified fusion protein significantly lengthened the activated partial thromboplastin time and thrombin time and inhibited the amidolytic activity of thrombin. The fibrinolytic activity was almost equal to that of recombinant staphylokinase as measured with a thrombelastograph. Platelet aggregation was not markedly inhibited by PLATSAK, probably due to the unfavourable three dimensional structure, with the Arg-Gly-Asp sequence buried inside. Our results confirm that it is feasible to design and produce a hybrid multifunctional protein that targets various components of the haemostatic process.

Rifampicin resistance in Mycobacterium tuberculosis--rapid detection and implications in chemotherapy.

OBJECTIVES: Tuberculosis treatment and susceptibility testing are cumbersome, especially in the case of multidrug-resistant (MDR) Mycobacterium tuberculosis. It is known that mutations in the rpoB gene of M. tuberculosis lead to resistance to rifampicin (RMP). In this study, an attempt was made to apply molecular techniques for rapid detection of antibiotic resistance in clinical isolates of M. tuberculosis. DESIGN, SETTINGS AND SUBJECTS: RMP-resistant clinical isolates of M. tuberculosis from South Africa (N = 120) with unique resistant patterns were selected for calculation of resistance frequencies, and 74 MDR isolates of M. tuberculosis from different geographical origins were used for microbiological and molecular analysis. The polymerase chain reaction (PCR) technique was applied for amplification of a previously described region around a cluster of mutations in the rpoB gene, and single-stranded conformational polymorphism (SSCP) analysis was optimised to screen for mutations in the amplified region. RESULTS: The results showed that an optimised PCR-SSCP procedure could detect a cluster of mutations in the rpoB gene (for RMP resistance) in 95% of RMP-resistant isolates. This procedure could therefore be used in the prediction of RMP resistance. Evidence was obtained that these mutations can be screened for directly from BACTEC cultures or even directly from Ziehl-Neelsen-positive sputum samples. Statistical analysis also showed that this locus can be used to predict the presence of an MDR isolate, which may have important implications in decisions concerning chemotherapy. CONCLUSION: It is currently not feasible to test all tuberculosis cases, but application of the PCR-SSCP technology in the prediction of multidrug resistance in M. tuberculosis isolates may be important in patients, especially where frequencies are high for drug-resistant isolates This methodology could reduce the time required for sensitivity testing from approximately 6-12 weeks to a few days.

Molecular characterization of a Galactomyces geotrichum lipase, another member of the cholinesterase/lipase family.

Geotrichum candidum secretes several lipase isoenzymes, differing in their selectively towards esters of long chain fatty acids with a cis-9 double bond. One group shows an absolute selectively towards these fatty acid esters, the other group has a more relaxed specificity and will also hydrolyze other long chain fatty acid esters. Galactomyces geotrichum secrets a lipase that has the same specificity as the latter group. The corresponding lipase gene was cloned from Galactomyces geotrichum. From an alignment of our enzymes' primary structure with those of different strains of Geotrichum candidum, remarkable conservation is evident and it is not yet possible to identify residues/structures responsible for differences in fatty acid specificity. Comparison of the GCL/GGL family with a variety of lipases from other sources, indicated that they are more related to mammalian than microbial lipases.

Mutations in katG gene sequences in isoniazid-resistant clinical isolates of Mycobacterium tuberculosis are rare.

In this study, a battery of oligonucleotides was directed toward the katG gene and PCR-single-stranded conformation polymorphism (SSCP) analysis was used to search for katG gene deviations in clinical isolates of Mycobacterium tuberculosis from different geographical regions. Since a complete deletion of the katG gene was not found, it is suggested that deletion is not a major mechanism of isoniazid (isonicotinic acid hydrazide; INH) resistance in these isolates. However, 7 of 39 isolates (4 of 25 from South Africa and 3 of 14 from other geographical regions) showed mobility shifts by SSCP analysis, suggesting aberrations in the katG gene. Direct sequence analysis confirmed that the mobility shifts were due to Thr-275-->Ala (Thr275Ala), Arg409Ala, Arg463Leu, and Asp695Ala mutations and a 12-bp deletion in the 5' region of the katG gene. Mutations at codons 275, 463, and 695 created altered restriction sites for HhaI, MspI, and HaeIII, respectively, and sequence results, supported by restriction fragment length polymorphism analysis, suggested that the PCR-SSCP procedure is a good indicator of mutations in PCR-amplified fragments. Identical mutations at codons 463 and 275 were found in isolates from different geographical regions. This may suggest a common evolutionary event, but one of the control isolates (susceptible to INH [3%; n = 30]) also had a mutation at codon 463. The results suggest that variations in the katG coding gene sequences of INH-resistant isolates of M. tuberculosis are infrequent and that defects in other regions of the M. tuberculosis genome are of equal or greater importance in contributing to the acquisition of resistance to INH.

The clinical pathology of heartwater. III. Changes in blood clotting, blood calcium, blood protein, haematocrit and white-cell counts in sheep with experimentally induced heartwater.

Studies to evaluate changes in blood clotting, blood calcium and protein, the haematocrit and white-cell counts were undertaken in seven sheep with experimentally induced heartwater. A marked decline in thrombocyte count was recorded during the acute stage of the disease. This was associated with increases in both prothrombin time (PT) and activated partial thromboplastin time (APTT); fibrinogen increased while there was no detectable increase in fibrinogen degradation products (FDP). At the same time total serum protein (TSP), albumin and globulin dropped very sharply; total calcium showed a progressive drop but ionized calcium rose initially and was followed by a terminal decline. The total leucocyte count showed a terminal increase while the haematocrit dropped progressively.

Conservation of binding site specificity of three yeast DNA binding proteins.

Sequence specific binding of protein extracts from 13 different yeast species to three oligonucleotide probes and two points mutants derived from Saccharomyces cerevisiae DNA binding proteins were tested using mobility shift assays. The probes were high affinity binding sites for GRF1/RAP1/ABF1 and CP1/CPF1. Most yeasts in the genus Saccharomyces showed specific binding to all three probes and also displayed similar sequence requirements when challenged by molar excesses of mutant probes. The affinities for the probes varied amongst the other yeasts tested, but in general, CPF1 binding activity was the most widespread, while the other two were more limited.