Experimental Assessment of Right Ventricular Function in Normal Pigs with a Left Ventricular Assist Device

Abstract: Right ventricular (RV) failure during the use of a left ventricular assist device (LVAD) is the leading cause of death in circulatory support patients. Previous work, both experimentally and clinically, has shown the difficulties in predicting the behavior of the right ventricle at the start of LVAD. An experimental study has been designed to evaluate RV functional changes during LVAD and its relation to preload changes. The model used adult mongrel pigs (n = 10). Right ventricular functional parameters were measured with a thermodilution RV ejection fraction catheter. The left ventricle was supported by a Nippon Zeon blood pump. Two groups were studied, the first one was the LVAD–off group (n = 5) and the other was the LVAD–on group (n = 5) which was supported by LVAD at maximum flow. Change of cardiac output, mean pulmonary artery pressure (PAP), RV stroke work, and RV ejection fraction in both groups were not significantly different. However, the relationship between right ventricular end–diastolic pressure (RV–EDP) and right ventricular stroke volume (RVSV) was significantly changed at a high level of RV–EDP. When RV–EDP was over 6. 5 mm Hg in the LVAD–off group, RVSV decreased to 52. 3 ± 11. 5 ml while in the LVAD–on group, RVSV increased to 97. 2 ± 22. 0 ml. The change in PAP in the LVAD–on group was lower than in the LVAD–off group. We conclude that, at the volume overload state, LVAD can reduce the afterload of the right ventricle and maintain Frank–Starling's effect, thus having a beneficial effect on right ventricular performance.     

Guanidinium-carboxylate interactions

The crystal structures of the 1:1 complexes methylguanidinium benzylhydrogenmalonate, (C₂N₃H₈)⁺(C₁₀H₉O₄)^?, MGD.BMAL, and methylguanidinium ethylhydrogenmalonate, (C₂N₃H₈)⁺(C₅H₇O₄)^?, MGD.EMAL, and of the 2:1 complex methylguanidinium sulfate, (C₂N₃H₈)₂SO₄, have been determined from three-dimensional X-ray data. For MGD.BMAL, the complex crystallizes in the triclinic space group P with two formula units in a cell of dimensions a = 6.277(5), b = 8.470(3), c = 13.191(6)Å, α= 91.01(1), β= 99.64(9), γ= 90.83(5)°. The structure has been refined to a final value of R = 0.061 based on 1511 intensities. The MGD.EMAL complex is also triclinic, space group P with two molecules in a cell of dimensions a = 9.254(7), b = 9.625(6), c = 6.778(2) Å, α= 109.6(1), β= 100.8(1), γ= 62.7(1)Å. The crystals of this compound are of low quality, and the final value is R = 0.109 based on 706 intensities. (MGD)₂SO₄ is orthorhombic, space group P2₁2₁2₁, with four molecules in a cell of dimensions a = 7.100(4), b = 12.151(3), c = 13.108(2) Å. Refinement has converged to R = 0.054 based on 907 data. All three crystals exhibit extensive interionic hydrogen bonding. The hydrogen bonding in MGD.BMAL includes a Type B interaction and a Type 1 interaction, the latter being a pairwise interaction from both amino nitrogen atoms on the cation to two carboxylate oxygen atoms from the two different carboxylate groups in an anion. In MGD.EMAL, the anion participates in both a Type A and a Type B pairwise interaction with two neighboring cations. The possible implications of the hydrogen bonding patterns in these two compounds for the role of arginyl side chains in protection of γ-carboxyglutamate residues from decarboxylation are discussed.     

Bone marrow transplantation for erythroleukemia: A case report

A 2 year old girl was diagnosed as having erythroleukemia (EL; M6 according to the French-American-British classification). After one course of low-dose cytosine arabinoside (Ara-C), complete remission was obtained. After three courses of low-dose Ara-C for consolidation, allogeneic bone marrow transplantation was performed from HLA-identical sibling. The course of post-transplantation was uneventful. Two years after transplantation, she continues to have durable engraftment and remission. In children with EL, conventional chemotherapy appears to be inadequate for producing durable long-term disease-free survival. Bone marrow transplantation should be considered in children with EL, in cases where suitable donors are available.     

Cytomegalovirus infection during immunosuppressive therapy for diffuse parenchymal lung disease

Background and objective: Cytomegalovirus (CMV) infection is a life‐threatening condition in patients with diffuse parenchymal lung diseases (DPLDs), who are receiving immunosuppressive therapy. The aim of this study was to describe the clinical features of CMV infection and to propose a strategy for managing CMV infection in patients with DPLD who are receiving immunosuppressive therapy. Methods: A retrospective longitudinal observational study was performed on 69 patients with DPLDs (39 with acute/subacute onset, 30 with chronic onset) who were receiving immunosuppressive therapy and were positive for CMV pp65 antigen (CMV‐pp65Ag) in peripheral blood leukocytes (PBLs). Results: Clinical CMV disease and subclinical CMV antigenaemia developed in 23 and 46 patients, respectively. The cut‐off level of CMV‐pp65Ag indicating clinical CMV disease, as determined by receiver operator characteristic curve analysis, was 7.5 cells per 5 × 10⁴ PBLs. Multivariate analysis revealed that early CMV infection was associated with acute/subacute onset of underlying DPLD and with respiratory dysfunction at the commencement of immunosuppressive therapy. Multivariate analysis also suggested that the acute/subacute onset of underlying DPLD, a CMV‐pp65Ag titre of >7.5 cells per 5 × 10⁴ PBLs, and C‐reactive protein levels ≥10 mg/L indicated a poor prognosis. Conclusions: We recommend that CMV‐pp65Ag antigenaemia of >7.5 cells per 5 × 10⁴ PBLs in patients with DPLD should be treated with ganciclovir. Patients with lower levels of CMV‐pp65Ag antigenaemia should be closely monitored or treated with ganciclovir if the clinical findings suggest a poor prognosis.     

Testosterone administration promotes regeneration of chemically impaired spermatogenesis in rats

AIM: It has been proposed that gonadotropin-releasing hormone (GnRH) analog administered after testicular damage stimulates the recovery of spermatogenesis. However, GnRH analogs suppress the function of sex accessory organs. In this study, we investigated whether testosterone also stimulates the regeneration of rat spermatogenesis after exposure to busulfan. METHODS: Male Fisher rats were divided into three groups of five each and all rats were treated with busulfan, 25 mg/kg, intraperitoneally at week 0. Group A served as the control. The other two groups received testosterone enanthate, 8 mg/kg, subcutaneous injections at 3 week intervals two times before (group B) or three times after (group C) busulfan. States of spermatogenesis were evaluated by histology and by the number of spermatid nuclei per testis at week 25. RESULTS: The mean percentage of 'recovered' seminiferous tubules plus or minus standard deviation was 10.3 +/- 7.8% in group A and 2.1 +/- 1.2% in group B. In both groups, more than 80% of the tubules remained degenerated. However, testes of group C rats showed an improvement of up to 37.1 +/- 20.5% (P < 0.05). The significant recovery of spermatogenesis was also demonstrated in group C by counting the number of spermatid nuclei per testis ([78.8 +/- 57.5] x 106). However, the count was only (7.6 +/- 13.5) x 106 and (0.52 +/- 1.0) x 106 in group A and B, respectively. CONCLUSIONS: Testosterone administration after severe testicular damage enhanced the regeneration of spermatogenesis in rats. We assumed that supplementary doses of testosterone would be more practical for clinical application than GnRH analogs, because exogenous testosterone maintains androgenicity.     

Cyclophosphamide-Induced Urinary Bladder Cancer: A Case Report

A case of carcinoma of the bladder developing in a patient whoreceived cyclophosphamide therapy for multiple myeloma over5 yr is presented. Literature reviews and possible mechanismsof urinary bladder carcinogenesis associated with cyclophosphamideare discussed.     

Examination of Stent Deformation and Gap Formation after Complex Stenting of Left Main Coronary Artery Bifurcations Using Microfocus Computed Tomography

Background: Fluoroscopy and intravascular ultrasound (IVUS) lack sufficient resolution for assessing the results of complex stenting in true bifurcation lesions.
Objectives: After diverse bifurcation stenting at the left main coronary artery (LM) bifurcation model, the results were examined using microfocus computed tomography (MFCT).
Methods: The strut distribution of three kinds of stents deployed on a straight vessel segment was investigated. Classical crush, double kissing (DK)–double crush, and culotte stenting were performed on a three-dimensional (3D) LM model. The results were assessed using cross-sectional, longitudinal, and 3D reconstruction views of MFCT.
Results: Nonuniform strut distribution was observed in a corrugated stent design deployed on a straight vessel segment. Following classical crush stenting, a relatively large gap at the nonmyocardial site was observed in the corrugated stents. When the guidewire recrossed outside the ostium of the crushed side branch stent, kissing balloon inflation caused further crushing of the stent at the more distal segment. The dilated strut rose up from the main vessel bed after the first kissing balloon inflation in DK crush stenting; the advantage of DK would be cancelled after main vessel stenting due to recrushing the raised strut. The culotte stenting with closed-cell stents showed the restriction of the expansion at the branch ostium when it was dilated with a 3.5-mm balloon. The culotte stenting with open-cell-based stents showed a good stent apposition except for a tiny gap and small metallic carina at the distal bifurcation.
Conclusion: MFCT analysis in the 3D phantom model is useful to assess the structural deformation of the stents and gap on vessel wall coverage after complex stenting at the LM bifurcation.