Influence of exercise rehabilitation on myocardial perfusion and sympathetic heart innervation in ischaemic heart disease

Exercise rehabilitation improves the clinical status in ischaemic heart disease. The purpose of this study was to assess the influence of exercise rehabilitation on myocardial perfusion and sympathetic heart innervation. Sixteen patients with ischaemic heart disease and previous myocardial infarction were investigated by means of exercise/rest tetrofosmin and metaiodobenzylguanidine (MIBG) exercise/rest single-photon emission tomography (SPET) studies, before and 6 months after starting an exercise rehabilitation programme. Tomograms were divided into 15 segments, and these were grouped into five myocardial anatomical regions. Regional uptake of both tracerswas quantified and expressed as a percentage of maximumpeak activity. The percentage ≤55% was chosen to evaluate defect size, and the results were expressed as a percentage of left ventricular mass. Areas with perfused and denervated myocardium and areas with ischaemic myocardium were calculated. In addition, regions with <75% of peak activity in the exercise perfusion study at baseline were divided into two groups according to whether there was an increase in peak activity of >10% (representing reversible regional defects) or an increase of <10% (representing fixed regional defects) in the rest study. These percentages were compared with the percentages obtained in the innervation study, and with the percentages obtained in exercise/rest perfusion and innervation studies performed 6 months after starting rehabilitation. Myocardial perfusion defects were significantly smaller than myocardial innervation defects before and 6 months after starting exercise rehabilitation. The area of ischaemia 6 months after starting exercise rehabilitation was significantly smaller than that before rehabilitation (0.31%± 1.4% vs 1.4%±1.6%, P<0.01). The size of innervation defects and the area of perfused and denervated myocardium did not show significant differences between the two studies performed before and 6 months after starting exercise rehabilitation. In reversible regional defects the percentage of peak activity was significantly increased 6 months after starting exercise rehabilitation in exercise and rest studies (P<0.001), while in fixed regional defects it was significantly increased only in exercise studies (P<0.001). There was no significant change in the regional MIBG percentages. We conclude that in ischaemic heart disease, exercise rehabilitation over a period of 6 months improves myocardial perfusion, but does not cause changes in sympathetic myocardial innervation. Received 12 August and in revised form 17 November 1999     

Correlation of beta-lactamase stability and antibacterial activity of beta-lactams in beta-lactamase-producing bacteria and respective transconjugants

A total of 343 Gram-negative bacteria were isolated and identified from urine specimens of patients with urinary tract infections. All the bacteria were investigated for their production of beta-lactamases by the nitrocefin test. beta-lactamase-producing strains were tested by the Datta method to detect any transfer of beta-lactamase production to a receiving E. coli K12 RN-strain. MICs of six beta-lactamase-stable compounds (ceftazidime, ceftriaxone, cefamandole, cefoxitin, cefotaxime, cefuroxime) were determined against all the beta-lactamase transferring bacteria and their respective transconjugants by a miniaturized dilution broth method. beta-lactamases produced by donors and transconjugants were purified and identified by determination of the isoelectric point by focusing; their hydrolytic activity was assessed by a spectrophotometric method using cytochrome c reduction. A total of 129 bacteria out of 343 produced beta-lactamases and 27 of these transferred the beta-lactamase production by conjugation. The beta-lactamases isolated from donors and transconjugants had the same pl and the same substrate profile. Ceftazidime was more stable to all the beta-lactamases isolated and more active against all the bacteria examined than the other compounds.     

Aortic valve morphology definition with transthoracic combined with transesophageal echocardiography in a population with high prevalence of bicuspid aortic valve

Objective:To assess the utility of transthoracic echocardiography (TTE) with second harmonic combined with transesophageal echocardiography (TEE) in defining aortic valve morphology in a subset of patients with a high prevalence of bicuspid aortic valve. Methods and Materials: Patients (n=174) with dilated aortic root were consecutively evaluated using, initially, TTE. The aortic valve structure was assigned as tricuspid, bicuspid or undefined. In those assigned as bicuspid or undefined, TEE was performed. Other factors that could affect valve morphology assignment were recorded and evaluated in multivariate analysis. Results: TTE was able to characterise 89% of the tricuspid valves and 56% of the bicuspid. Bicuspid structure was the only variable that, in the multivariate analysis, was related to the inability to definitively assign aortic valve morphology (OR=0.13). TEE was performed in 59 patients and the morphology was definitively assigned in 56 of them (95%). TEE diagnosed 15 bicuspid valves in addition to confirming the 17 identified by TTE. Overall, using TTE combined with TEE we were able to correctly assign valvular morphology in 98% of patients. Conclusion: In a subset of patients with a high prevalence of bicuspid aortic valve, combination of TTE and TEE should be considered to define aortic valve morphology. TEE identifies an important number of patients with BAV.     

Rat CCl4‐induced cirrhosis plus total portal vein ligation: a new model for the study of hyperammonaemia and brain oedema

Introduction: Animal models used to study hyperammonaemic disorders related to chronic liver disease are unsatisfactory. These animals only develop hyperammonaemia and brain oedema when fed with diets supplemented with amonium acetate. Aim: To develop a novel experimental model of hyperammonaemia and brain oedema in CCl₄‐induced cirrhosis in rats. Methods: Four groups were studied: rats with sham intervention (S), rats with total portal vein ligation (TPVL), cirrhotic rats (LC), and cirrhotic rats with TPVL (LC+TPVL). When ascites was diagnosed, oral glutamine challenge (OGC) test was performed. Blood, liver, lungs and brain samples were collected to quantify liver function parameters, plasmatic and cerebral ammonia, endotoxaemia, liver and brain histology, brain oedema and portosystemic shunting degree. Results: LC+TPVL rats showed a significant increase in portosystemic shunting when compared with LC group and a significant derangement in liver function when compared with TPVL group. These alterations resulted in a significant increase in plasmatic and brain ammonia concentrations and a higher plasmatic endotoxaemia as compared with others. Similarly, the area under OGC curve was significantly increased in LC+TPVL group as compared with the others, and correlates with portal shunting. Low‐grade brain oedema was only observed in LC+TPVL group. All cirrhotic groups showed liver regeneration nodules and type‐II Alzheimer astrocytes Conclusion: LC+TPVL reproduce the main alterations – portosystemic shunting, plasmatic and cerebral hyperammonaemia and low‐grade brain oedema – observed in cirrhotic patients with hepatic encephalopathy.     

Double CEBPE-IGH rearrangement due to chromosome duplication and cryptic insertion in an adult with B-cell acute lymphoblastic leukemia

In an adult case of B-cell acute lymphoblastic leukemia (B-ALL) with a complex karyotype, both chromosomes 14 were involved in unbalanced rearrangements, specifically, der(14)t(13;14)(q21;q21) and dup(14)(q11q32). Fluorescence in situ hybridization (FISH) detected two CEBPE-IGH rearrangements at the dup(14). One was found at the duplication breakpoint and the other derived from insertion of CEBPE into an apparently normal IGH locus. Hypotheses to account for these unusual chromosomal rearrangements are discussed. This case provides the first evidence that chromosome duplication and cryptic insertion produce the CEBPE-IGH fusion and that more than one CEBPE-IGH recombination can occur in a leukemic cell. Our findings confirm that deregulated CEBPE plays a crucial role in the pathogenesis of CEBPE-IGH positive B-ALL.