Real-World Phosphate Binder Use among Dialysis-Dependent Patients with CKD

INTRODUCTION

For patients with chronic kidney disease (CKD), the need for phosphate binder (PB) treatment peaks at onset of dialysis. This real-world study assessed rates of PB utilization and switching in patients with dialysis-dependent CKD (DD-CKD).

METHODS

We identified patients with PB utilization among those with prevalent DD-CKD using 2018-2019 Medicare Parts A/B/D data. Patients were assigned to cohorts based on primary (most frequently used) PB among calcium acetate, ferric citrate, lanthanum carbonate, sevelamer (hydrochloride and carbonate), sucroferric oxyhydroxide. We measured proportion of patients who were adherent (proportion of days covered >80%) and persistent (patients whose last 90 days of outpatient dialysis reported PB use). Net switching rates were calculated as the difference between switches to and from the primary agent.

RESULTS

We identified 136,912 patients with PB use. Proportion of patients adherent ranged from 63.8% (lanthanum carbonate) to 67.7% (sevelamer) and persistent from 85.1% (calcium acetate) to 89.5% (ferric citrate). Most patients (73%) used the same PB throughout the study. Overall, 20.5% of patients experienced one switch and 2.3% two or more. Positive net switching rates were observed for ferric citrate, sucroferric oxyhydroxide, and lanthanum carbonate (2-10%) but negative for sevelamer and calcium acetate (-2% to -7%).

CONCLUSION

Adherence and persistence rates were low with slight variation across PBs. Net positive switching occurred for ferric citrate, sucroferric oxyhydroxide, and lanthanum carbonate. Further studies are needed to determine the reasons for these findings and could identify opportunities for better control of phosphate levels among patients with CKD.

POS0835 RELAPSE RATES IN NEWLY DIAGNOSED AND ESTABLISHED PATIENTS WITH ANTI-NEUTROPHIL CYTOPLASMIC AUTOANTIBODY (ANCA)-ASSOCIATED VASCULITIS

Background

Anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis is a life- or organ-threatening condition in which patients experience severe inflammation of small- to medium-sized blood vessels. Clinical relapses are common in ANCA-associated vasculitis and previously reported rates vary between 21-89% at 5 years depending on the regimens used for induction and maintenance (1). Relapses require repeated treatment with immunosuppressive therapy and increase the risks of adverse events.

Objectives

Identify the incidence of relapse in newly diagnosed and established granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) patients in commercially insured and Medicare fee-for-service (FFS) populations.

Methods

Using the 2016-2019 Milliman proprietary commercial claims data and Medicare 100% FFS Innovator Research data, newly diagnosed and established GPA and MPA patients were identified in index years 2017 and 2018. Newly diagnosed patients were identified as those with at least two qualifying claims on different dates of service, coded with a GPA or MPA ICD-10-CM code, and no claim coded with GPA or MPA in the 12 months prior to their first claim. Established patients required 12-months continuous enrollment in the year of their established status and 12-months continuous enrollment in the year prior to their established status. Relapses for incident patients were identified during the 7 to 12 months after the index date for newly diagnosed patients to avoid mischaracterizing claims around the time of the initial diagnosis as relapses and over a 12-month period for the established patients.

Relapse was defined based on specific inpatient and outpatient claims with a GPA or MPA diagnosis code or claims coded with one major or at least three minor vasculitis signs or symptoms followed by a claim within 30 days for plasmapheresis or cyclophosphamide or glucocorticoids (> 20 mg prednisolone equivalent) or 2+ rituximab claims within 30 days of each other. Relapse had to occur 30 days after the previous event and 6 months after index date for incident patients.

Results

542 (GPA) and 83 (MPA) commercially insured newly diagnosed patients with 12 months eligibility following their index date and 1,748 (GPA) and 184 (MPA) commercially insured established patients were identified. 15.5% (GPA) and 15.7% (MPA) newly diagnosed patients relapsed during months 7-12 after diagnosis and 27.9% (GPA) and 29.3% (MPA) established patients relapsed over a 12-month period.

2,397 (GPA) and 655 (MPA) Medicare FFS newly diagnosed patients with 12 months of eligibility following their index date and 5,955 (GPA) and 833 (MPA) Medicare FFS established patients were identified. 19.3% (GPA) and 27.2% (MPA) newly diagnosed patients relapsed during months 7-12 after diagnosis and 33.5% (GPA) and 40.2% (MPA) established patients relapsed over a 12-month period.

Conclusion

Using administrative healthcare claims, we observed relapse rates after GPA and MPA diagnosis ranging between 15.5-27.2% in months 7-12 after diagnosis for newly diagnosed patients and between 27.9-40.2% over a 12-month period for established patients. There is an unmet need for new therapies that sustain remission and decrease relapse rates in patients with ANCA-associated vasculitis. This is an important clinical strategy to reduce the risks of adverse events from long-term immunosuppression therapy and decrease end-organ damage.

References

[1]Salama AD. Relapse in Anti-Neutrophil Cytoplasm Antibody (ANCA)-Associated Vasculitis. Kidney Int Rep. 2019;5(1):7-12.

Disclosure of Interests

Kate Fitch Consultant of: ChemoCentryx, Carol Bazell Consultant of: ChemoCentryx, Steven Metz Consultant of: ChemoCentryx, Irene von Hennigs Shareholder of: ChemoCentryx, Consultant of: ChemoCentryx, Employee of: ChemoCentryx

Effect of cholesterol re-supplementation and atorvastatin on plaque composition in the thoracic aorta of New Zealand white rabbits

BACKGROUND

Effects of re-supplementation of a cholesterol-enriched diet (CEDrs) on size, cholesterol content and morphology of already existing plaques are not known to date.

METHODS

A group of rabbits received standard chow (SC) for 6 weeks ("negative control"; for plasma lipid measurements only). Group I-IV received 2% CED (induction) for 6 weeks; thereafter, groups II-IV have been fed a SC (= cholesterol withdrawal) for 68 weeks. Afterwards, feeding of groups II-IV was continued as follows: Group II - 10 weeks SC, group III - 4 weeks 0.5% CED (~re-supplementation), afterwards 6 weeks SC (~withdrawal again); group IV - 4 weeks 0.5% CED (re-supplementation) + atorvastatin (2.5 mg/kg body weight/day), afterwards 6 weeks SC (~withdrawal again) + atorvastatin. Plasma lipids, but also plaque size, morphology and cholesterol contents of thoracic aortas were quantified.

RESULTS

After CEDrs, plasma cholesterol levels were increased. However, after withdrawal of CEDrs, plasma cholesterol levels decreased, whereas the cholesterol content of the thoracic aorta was increased in comparison with the group without CEDrs. Plaque size remained unaffected. Atorvastatin application did not change plasma cholesterol level, cholesterol content of the thoracic aorta and plaque size in comparison with the group without drug treatment. However, atorvastatin treatment increased the density of macrophages (MΦ) compared with the group without treatment, with a significant correlation between densities of MΦ (Mac-1⁺) and apoptotic (TUNEL⁺; TP53⁺), antigen-presenting (HLA-DR⁺) or oxidatively stressed (SOD2⁺) cells.

CONCLUSIONS

In rabbits with already existing plaques, CEDrs affects plaque morphology and cellular composition, but not plaque size. Despite missing effects on plasma cholesterol levels, cholesterol content of the thoracic aorta and size of already existing atherosclerotic plaques, atorvastatin treatment transforms the already existing lesions to a more active form, which may accelerate the remodelling to a more stable plaque.

Graphene-based acceptor molecules for organic photovoltaic cells: a predictive study identifying high modularity and morphological stability

An idealized donor:acceptor pair is proposed for improved organic photovoltaic lifetimes and efficiencies.

C^C* cyclometalated platinum(II) N-heterocyclic carbene complexes with a sterically demanding β-diketonato ligand – synthesis, characterization and photophysical properties

Neutral cyclometalated platinum(ii) N-heterocyclic carbene complexes [Pt(C^C*)(O^O)] with C^C* ligands based on 1-phenyl-1,2,4-triazol-5-ylidene and 4-phenyl-1,2,4-triazol-5-ylidene, as well as acetylacetonato (O^O = acac) and 1,3-bis(2,4,6-trimethylphenyl)propan-1,3-dionato (O^O = mesacac) ancillary ligands were synthesized and characterized. All complexes are emissive at room temperature in a poly(methyl methacrylate) (PMMA) matrix with emission maxima in the blue region of the spectrum. High quantum efficiencies and short decay times were observed for all complexes with mesacac ancillary ligands. The sterically demanding mesityl groups of the mesacac ligand effectively prevent molecular stacking. The emission behavior of these emitters is in general independent of the position of the nitrogen in the backbone of the N-heterocyclic carbene (NHC) unit and a variety of substituents in 4-position of the phenyl unit, meta to the cyclometalating bond.

Automatic 3D ultrasound calibration for image guided therapy using intramodality image registration

Many real time ultrasound (US) guided therapies can benefit from management of motion-induced anatomical changes with respect to a previously acquired computerized anatomy model. Spatial calibration is a prerequisite to transforming US image information to the reference frame of the anatomy model. We present a new method for calibrating 3D US volumes using intramodality image registration, derived from the 'hand-eye' calibration technique. The method is fully automated by implementing data rejection based on sensor displacements, automatic registration over overlapping image regions, and a self-consistency error metric evaluated continuously during calibration. We also present a novel method for validating US calibrations based on measurement of physical phantom displacements within US images. Both calibration and validation can be performed on arbitrary phantoms. Results indicate that normalized mutual information and localized cross correlation produce the most accurate 3D US registrations for calibration. Volumetric image alignment is more accurate and reproducible than point selection for validating the calibrations, yielding <1.5 mm root mean square error, a significant improvement relative to previously reported hand-eye US calibration results. Comparison of two different phantoms for calibration and for validation revealed significant differences for validation (p = 0.003) but not for calibration (p = 0.795).

Clinical evaluation of the Levitan Optical Stylet

A Levitan Optical Stylet with a modified curve was used in the operating theatre for 301 timed tracheal intubations. Jaw lift was provided manually instead of with a direct laryngoscope. All tracheas except one were intubated successfully (99.7%). Mean (SD) intubation times were 23 (24) s. Three patients (1%) suffered minor trauma. The modified Levitan Optical Stylet can be used without direct laryngoscopy as an effective, rapid and relatively atraumatic tool for intubation, even in difficult airways. It may be appropriate as an alternative or primary intubation technique instead of direct laryngoscopy.

Frequency and prognostic significance of occult tumor cells in lymph nodes in patients with adenocarcinoma of the papilla of Vater

BACKGROUND

Occurrence of tumor relapse is frequent in patients with carcinoma of the papilla of Vater despite the absence of residual tumor detectable at primary surgery. Therefore it has to be assumed that current tumor staging procedures fail to identify minimal amounts of tumor cells disseminated to secondary organs, which might be precursors of subsequent metastatic relapse. The aim of the study was to assess the frequency and prognostic impact of minimal tumor cell spread in lymph nodes classified as 'tumor-free' in routine histopathologic evaluation.

MATERIALS AND METHODS

A total of 41 'tumor-free' lymph nodes from 23 patients with adenocarcinoma of the papilla of Vater who underwent curative tumor resection (R0) were examined by immunohistochemistry with the monoclonal anti-EpCAM antibody Ber-EP4 for minimal disseminated tumor cells.

RESULTS

Twelve (29.3%) of the 41 'tumor-free' lymph nodes obtained from 9 (39.1%) of the 23 patients displayed EpCAM-positive cells. Kaplan-Meier survival analysis revealed that patients with EpCAM-positive cells in lymph showed a clearly reduced relapse-free and overall survival compared with patients without such cells. However, these differences were not statistically significant (p = 0.13 for relapse-free survival, p = 0.11 for overall survival).

DISCUSSION

Immunohistochemical assessment may refine the staging of resected lymph nodes in patients with carcinoma of the papilla of Vater. However, the presence of minimal disseminated tumor cells in lymph nodes had no significant impact on the prognosis in these patients.

Thrombose der Vena cava inferior sowie der Iliacal- und Femoralvenen bei einem 24-jährigen Patienten

HISTORY AND ADMISSION FINDINGS

A 24-year-old patient presented with nonspecific epigastric pain, general feebleness and weakness of both legs. The cardiopulmonary investigations were unremarkable. The abdomen was soft, without muscular resistance or local pressure tenderness. Both legs were moderately swollen without other findings.

INVESTIGATIONS

The laboratory tests showed an elevated D-dimer and fibrinogen, as well as a heterozygous factor V Leiden mutation. Both duplex ultrasonography and computed tomography revealed thrombosis of the distal inferior vena cava (IVC) and both iliac and femoral veins. A short segment of the IVC between the left renal and intrahepatic veins was a-genetic.

DIAGNOSIS, TREATMENT AND COURSE

Anticoagulation treatment with phenprocoumon was started for the deep vein thrombosis. At the one-year follow-up no thrombosis of the vena cava and the iliac and femoral veins was detected.

CONCLUSION

Thrombosis of the IVC in combination with a pelvic vein thrombosis is a rare condition in young patients. If this venous abnormality is found, thrombophilia should be considered in the differential diagnosis. Anticoagulation is the treatment of choice.

Stentless mitral valve implantation in comparison to conventional mitral valve repair or replacement at five years

OBJECTIVE

A chordally supported stentless mitral valve (SMV) may be a suitable prosthesis for patients with severe degenerative mitral valve disease. We analyzed the five-year results and compared them with results after conventional mitral valve repair or replacement.

METHODS

155 patients, operated on since August 1997, were evaluated. 53 patients (ages, 68 +/- 8 years, 37 female, valve repair not feasible) received a SMV (Quattro), 51 patients (69 +/- 9 years, 32 female) had mitral valve repair (MVR) and 51 patients (66 +/- 9 years, 32 female) had a conventional mitral valve replacement (MVP). There were no significant differences with respect to preoperative NYHA functional class, left ventricular ejection fraction, cardiac index and surgical risk, according to the EuroSCORE. Mean follow-up is 64 +/- 18 (21-89) months.

RESULTS

Surgery was performed using a median sternotomy (32 [SMV]/20 [MVR]/34 [MVP]) or a lateral mini-thoracotomy 21/31/17 approach. The SMV was safely attached to the papillary muscles. In-hospital mortality was 1, 2 and 4 respectively; re-operation was required in 6, 2 and 3 patients. Five-year survival rate was 80.6 +/- 4.4 % (SMV), 80.2 +/- 5.6 % (CMV) and 82.6 +/- 5.6 % (MVP), p = n.s. After hospital discharge, there was no significant difference in mortality in comparison to an age-matched control population. Echocardiography revealed acceptable SMV hemodynamics with preservation of left ventricular function.

CONCLUSION

Midterm results after SMV implantation are comparable to conventional approaches. Complete preservation of the annulo-ventricular continuity is advantageous and close to physiologic hemodynamics can be achieved. Long term follow-up is required.

Flexible polyimide probes with microelectrodes and embedded microfluidic channels for simultaneous drug delivery and multi-channel monitoring of bioelectric activity

The study of intracellular communication requires devices that can not only monitor the bioelectric activity, but also control and observe the biochemical environment at the cellular level. This paper reports on the development and characterisation of implantable polyimide microprobes that allow simultaneous, selective chemical delivery/probing and multi-channel recording/stimulation of bioelectric activity. The key component of the system is a flexible polyimide substrate with embedded microchannels that is batch-fabricated combining polyimide micromachining and a lamination technique. The devices provide platinum microelectrodes on both sides of the polyimide substrate with an active surface between 20 microm x 20 microm and 50 microm x 50 microm. The embedded microchannels permit highly localised drug delivery or probing at the tip of the device via channel outlets adjacent to the microelectrodes. The microelectrodes were characterised by electrical impedance spectroscopy and the microchannels were studied in microflow experiments. Two different fluid delivery schemes were explored in two different designs. The first device type consists of a simple combination of microchannels and microelectrodes on one substrate. Liquids are ejected at the tip of the device by pressure injection techniques. The second device was inspired by the so-called U-tube concept allowing for highly localised delivery of controlled amounts of liquids in the picoliters range. Thus, the influence of chemical compounds on the electrical activity of cells can be studied with high temporal and spatial resolution. The flexible, implantable devices can be used for studying the chemical and electrical information exchange and communication of cells in in vivo and in vitro experiments.

Perioperative use of the modified nasal trumpet in 346 patients

BACKGROUND

The modified nasal trumpet (MNT) is a prepackaged nasopharyngeal airway modified with distal holes and fitted with a 15 mm adaptor allowing connection to an anaesthesia circuit. It may be useful for airway management during anaesthesia.

METHODS

After applying a spray to constrict the nasal mucosa, we used the MNT in 346 spontaneously breathing patients for three indications: alone as an airway device during general anaesthesia, to provide supplemental oxygen immediately after extubation instead of by facemask, and to facilitate fibreoptic intubation during general anaesthesia.

RESULTS

The device was successful for giving supplemental oxygen after extubation (n=244) and facilitating fibreoptic intubation (n=28). When used as an airway for general anaesthesia, it was only successful without manipulation in 33 of 74 patients (45%). The MNT was easy to insert in awake patients. We encountered six complications: one MNT folded in the pharynx, and five patients (1.4%) experienced nosebleeds.

CONCLUSIONS

The MNT was disappointing as a primary airway device under general anaesthesia but was useful for giving oxygen after extubation and for facilitation of fibreoptic intubation. It can cause nosebleeds.

Polyimide and SU-8 microfluidic devices manufactured by heat-depolymerizable sacrificial material technique

The following paper describes a sacrificial layer method for the manufacturing of microfluidic devices in polyimide and SU-8. The technique uses heat-depolymerizable polycarbonates embedded in polyimide or SU-8 for the generation of microchannels and sealed cavities. The volatile decomposition products originating from thermolysis of the sacrificial material escape out of the embedding material by diffusion through the cover layer. The fabrication process was studied experimentally and theoretically with a focus on the decomposition of the sacrificial materials and their diffusion through the polyimide or SU-8 cover layer. It is demonstrated that the sacrificial material removal process is independent of the actual channel geometry and advances linearly with time unlike conventional sacrificial layer techniques. The fabrication method provides a versatile and fast technique for the manufacturing of microfluidic devices for applications in the field of microTAS and Lab-on-a-Chip.

Agrobacterium-mediated large-scale transformation of wheat (Triticum aestivum L.) using glyphosate selection

An Agrobacterium-mediated transformation system with glyphosate selection has been developed for the large-scale production of transgenic plants. The system uses 4-day precultured immature embryos as explants. A total of 30 vectors containing the 5-enol-pyruvylshikimate-3-phosphate synthase gene from Agrobacterium strain CP4 (aroA:CP4), which confers resistance to glyphosate, were introduced into wheat using this system. The aroA:CP4 gene served two roles in this study-selectable marker and gene of interest. More than 3,000 transgenic events were produced with an average transformation efficiency of 4.4%. The entire process from isolation of immature embryos to production of transgenic plantlets was 50-80 days. Transgenic events were evaluated over several generations based on genetic, agronomic and molecular criteria. Forty-six percent of the transgenic events fit a 3:1 segregation ratio. Molecular analysis confirmed that four of six lead transgenic events selected from Agrobacterium transformation contained a single insert and a single copy of the transgene. Stable expression of theAROA:CP4 gene was confirmed by ELISA through nine generations. A comparison of Agrobacterium-mediated transformation to a particle bombardment system demonstrated that the Agrobacterium system is reproducible, has a higher transformation efficiency with glyphosate selection and produces higher quality transgenic events in wheat. One of the lead events from this study, no. 33391, has been identified as a Roundup Ready wheat commercial candidate.

A modified nasal trumpet to facilitate fibreoptic intubation

BACKGROUND

The modified nasal trumpet (MNT) is a standard nasopharyngeal airway with an added distal fenestration and fitted with a 15 mm adaptor to permit connection to an anaesthesia circuit.

METHODS

Based on its successful use as an emergency device in the 'cannot intubate, cannot ventilate' scenario, we considered that the MNT would aid fibreoptic intubation by providing a patent airway, spontaneous ventilation, and inhalation anaesthesia during the procedure. We report use of the MNT for this purpose seven times in six patients with difficult airways.

RESULTS

In each case, the MNT allowed oxygenation and general anaesthesia while maintaining spontaneous ventilation when awake intubation was unsuccessful or not possible.

CONCLUSION

The MNT has a place in the operating room suites as a useful airway management device.

Development and characterization of murine monoclonal antibodies specific for dissimilatoric copper nitrite reductase

Several hybridoma cell lines from mice were established, producing monoclonal antibodies (MAbs) directed against the dissimilatoric copper nitrite reductase (dNIR) to detect actual denitrifying bacteria at the single cell level under nondestructive conditions in the environment. The mice were immunized with native or recombinant enzyme gained from two different bacteria, Ochrobactrum anthropi and Alcaligenes faecalis. The antibodies obtained could be divided into two groups according to their different specificities for dNIRs of different bacteria: One group of MAbs had a broad specificity for dissimilatoric copper nitrite reductases from bacteria of different phylogenetic taxa; the other group gave only a clear signal with the corresponding immunogen. None of the raised MAbs showed a cross reactivity with the dissimilatoric heme nitrite reductase. One MAb from each group (MAb dNIR1a and MAb dNIR29) has been selected for further investigation. Data of enzyme-linked immunosorbent assay (ELISA), Western blotting, and immunofluorescence-microscopy are presented and compared with phylogenetic data. Furthermore, results of Western blotting experiments with cells, grown without nitrate under aerobic conditions, and cells cultivated with nitrate under anaerobiosis, are shown.

[Possibilities of regression in arteriosclerosis]

We studied the hypercholesterolemic rabbit model in order to evaluate potentials of regression of arteriosclerosis by measuring various blood and plaque parameters. After induction of arteriosclerosis by feeding a 2% cholesterol-enriched diet (CHF) for 6 weeks, the highly increased blood lipid levels decreased significantly under normal diet, while the cholesterol concentration, the lumen stenosis, and the number of smooth muscle cells in the plaques of the thoracic aorta still significantly increased. Sixty-eight weeks after reaching normal blood lipid levels, cellular density and number of macrophages significantly diminished; cholesterol concentration and lumen stenosis did not change significantly, whereas the smooth muscle cells further increased. Arteriosclerotic arteries of elderly people demonstrated a similar structure as seen after long-term regression in our experiments.

Selective heterocyclic amidine inhibitors of human inducible nitric oxide synthase

The potency and selectivity of a series of 5-hetero-2-iminohexahydroazepines were examined as inhibitors of the three human NOS isoforms. The effect of ring substitution of the 5-carbon for a heteroatom is presented. Potencies (IC(50)'s) for these inhibitors are in the low micromolar range for hi-NOS with some examples exhibiting a 500x selectivity versus hec-NOS.

Polyimide-based microfluidic devices

This paper describes the development of polyimide-based microfluidic devices. A layer transfer and lamination technique is used to fabricate flexible microfluidic channels in various shapes and with a wide range of dimensions. High bond strengths can be achieved by cure cycle adaptation and surface treatment of the polyimide layers prior to bonding. The polyimide microchannels can be combined with metallization layers to fabricate electrodes inside and outside channels. The resulting devices can be used for flexible fluidic and electrical connectors, implantable fluid delivery devices, microelectrodes with embedded fluidic channels, chip-based flow cytometry and for a great variety of other applications in medical, chemical or biological research.

Intercaval block in normal canine hearts : role of the terminal crest

BACKGROUND

The intriguing monotony in the occurrence of intercaval conduction block during typical atrial flutter suggests an anatomic or electrophysiological predisposition for conduction abnormalities.

METHODS AND RESULTS

To determine the location of and potential electrophysiological basis for conduction block in the terminal crest region, a high-density patch electrode (10x10 bipoles) was placed on the terminal crest and on the adjacent pectinate muscle region in 10 healthy foxhounds. With a multiplexer mapping system, local activation patterns were reconstructed during constant pacing (S(1)S(1)=200 ms) and introduction of up to 2 extrastimuli (S(2), S(3)). Furthermore, effective refractory periods were determined across the patch. If evident through online analysis, the epicardial location of conduction block was marked for postmortem verification of its endocardial projection. Marked directional differences in activation were found in the terminal crest region, with fast conduction parallel to and slow conduction perpendicular to the intercaval axis (1.1+/-0.4 versus 0.5+/-0.2 m/s, P<0.01). In the pectinate muscle region, however, conduction velocities were similar in both directions (0.5+/-0.3 versus 0.6+/-0.2 m/s, P=NS). Refractory patterns were relatively homogeneous in both regions, with local refractory gradients not >30 ms. During S(3) stimulation, conduction block parallel to the terminal crest was inducible in 40% of the dogs compared with 0% in the pectinate muscle region.

CONCLUSIONS

Even in normal hearts, inducible intercaval block is a relatively common finding. Anisotropic conduction properties would not explain conduction block parallel to the intercaval axis in the terminal crest region, and obviously, refractory gradients do not seem to play a role either. Thus, the change in fiber direction associated with the terminal crest/pectinate muscle junction might form the anatomic/electrophysiological basis for intercaval conduction block.

Comparison of MIDCAP versus conventional CABG surgery regarding pain and quality of life

BACKGROUND

This prospective clinical trial focuses on pain and quality of life (QOL) after minimally invasive direct coronary artery bypass (MIDCAB) grafting versus conventional coronary artery bypass grafting (CABG).

METHODS

Group A consisted of 65 consecutive MIDCAB patients using an anterolateral mini-thoracotomy and the "off-pump" technique. Group B consisted of 95 computer-matched patients who underwent conventional CABG with cardiopulmonary bypass (CPB). Pain was graduated using the visual analog scale (VAS), and the verbal rating scale (VRS) [Troidl 1990]. QOL was evaluated at the time of discharge and three months after surgery using modified Nottingham Health Questionnaires that separate physical, social, activity, emotional, pain, and sleeping conditions.

RESULTS

Postoperative pain was higher after MIDCAB on postoperative day (POD) 1 (p< 0.002). From POD 4 onwards MIDCAB patients had less pain compared with the conventional group (p<0.04). MIDCAB patients required less pain medication from POD 4 onwards (p<0.05). QOL was significantly better in the MIDCAB group on POD 7 for physical (p< 0.038), activity (p< 0.016), pain (p< 0.041), and sleep (p<0.038) conditions. The three-month questionnaire showed significantly better levels for MIDCAB patients regarding physical (p< 0.03) and pain (p< 0.001) conditions, and a trend for activity (p< 0.08) and emotional (p<0.08) conditions.

CONCLUSION

Compared to patients undergoing conventional surgery, MIDCAB patients suffer more pain in the first three postoperative days, probably as a result of the lateral thoracotomy. From POD 4 onwards, MIDCAB patients are significantly better, experiencing less pain and showing better physical, activity, and sleeping conditions even three months after surgery. This can be attributed to the absence of median sternotomy and/or the avoidance of cardiopulmonary bypass.

Inosine-5'-monophosphate dehydrogenase is required for mitogenic competence of transformed pancreatic beta cells

The relation of inosine-5'-monophosphate dehydrogenase (IMPDH; the rate-limiting enzyme in GTP synthesis) to mitogenesis was studied by enzymatic assay, immunoblots, and RT-PCR in several dissimilar transformed pancreatic ss-cell lines, using intact cells. Both of the two isoforms of IMPDH (constitutive type 1 and inducible type 2) were identified using RT-PCR in transformed beta cells or in intact islets. IMPDH 2 messenger RNA (mRNA) and IMPDH protein were both regulated reciprocally by changes in levels of their end-products. Flux through IMPDH was greatest in rapidly growing cells, due mostly to increased uptake of precursor. Glucose (but not 3-0-methylglucose, L-glucose, or fructose) further augmented substrate uptake and also increased IMPDH enzymatic activity after either 4 or 21 h of stimulation. Serum or ketoisocaproate also increased IMPDH activity (but not uptake). Two selective IMPDH inhibitors (mycophenolic acid and mizoribine) reduced IMPDH activity in all cell lines, and, with virtually identical concentration-response curves, inhibited DNA synthesis (assessed as bromodeoxyuridine incorporation) in response to glucose, serum, or ketoisocaproate. Inhibition of DNA synthesis was reversible, completely prevented by repletion of cellular guanine (but not adenine) nucleotides, and could not be attributed to toxic effects. Despite the fact that modulation of IMPDH expression by guanine nucleotides was readily detectable, glucose and/or serum failed to alter IMPDH mRNA or protein, indicating that their effects on IMPDH activity were largely at the enzyme level. Precursors of guanine nucleotides failed, by themselves, to induce mitogenesis. Thus, adequate IMPDH activity (and thereby, availability of GTP) is a critical requirement for beta-cell proliferation. Although it is unlikely that further increases in GTP can, by themselves, initiate DNA synthesis, such increments may be needed to sustain mitogenesis.

Pain is significantly reduced by cryoablation therapy in patients with lateral minithoracotomy

BACKGROUND

In minimally invasive cardiac surgery use of a lateral minithoracotomy is associated with early postoperative rehabilitation but also relatively high pain levels during the first 3 postoperative days. Cryoablation therapy was evaluated prospectively.

METHODS

From April 1999 until September 1999, 57 patients underwent lateral minithoracotomy for mitral valve operation (n = 18) or minimally invasive direct coronary artery bypass grafting (n = 39). Intraoperatively, patients were randomly assigned to cryoablation or intercostal application of local anesthetic agents. A standardized questionnaire was used for prospective pain assessment on postoperative days 1 to 7.

RESULTS

From postoperative day 1 to 7 pain levels declined in all groups. Overall pain levels were significantly lower in the cryo group than in the control group (p < 0.0001, GLM). According to diagnoses, pain levels were significantly lower after MIDCABG and cryo versus control; after mitral valve operation they were lower in the cryo group and almost reached significance.

CONCLUSIONS

Cryoablation is easy to perform and leads to a significant reduction in pain and lower request for additional pain medication after lateral minithoracotomy in minimally invasive cardiac operation.