Protein fingerprinting and quantification of ß-casein variants by ultra-performance liquid chromatography-high-resolution mass spectrometry.

Infant formulations are constantly evolving as novel protein ingredients are added to make them more closely mimic the protein profile of human milk; however, precise analytical methods for characterizing and quantifying the major milk proteins in such formulations are currently lacking. This article describes an ultra-performance liquid chromatography-high-resolution mass spectrometry method for intact proteins that can efficiently detect, identify, and characterize the major milk proteins and their proteoforms (phosphorylation status, degree of glycation, genetic variants among others) in ingredients and final products, with an emphasis on detecting and quantifying specific genetic variants of ß-casein in infant formulas. Method sensitivity allows detection of ß-casein A1 in A2-based infant formulas with a limit of detection of 2% (grams of ß-casein A1 per 100 g of total ß-casein). Protein glycation affects signal intensity in a linear fashion, which permits proteins to be quantified from their mass spectrometry signals after correction according to their measured glycation index. The method was validated for the quantification of ß-casein in infant formulas. Repeatability ranged from 2 to 3% and intermediate reproducibility from 5 to 9%. Calculated ß-casein amounts ranged between 77 and 110% of the values based on formulations and published protein profiles for milk. Altogether, this method can be used for general fingerprinting as well as specific characterization and quantification of individual major milk proteins in dairy-based ingredients and products.

Molecular characterisation of Pinus sylvestris (L.) in Ireland at the western limit of the species distribution.

BACKGROUND: Scots pine (Pinus sylvestris L.) underwent significant population declines across much of northwest Europe during the mid-to-late Holocene and was thought to have become extirpated in Ireland from about 400 AD. However, most extant populations are plantations reintroduced from Scotland. Others are naturalised therefrom and one in Western Ireland is a putative relict. In this paper, Scots pine in Ireland are genetically described for the first time. RESULTS: Using two mitochondrial (mtDNA) loci, eight chloroplast (cpSSR) and 18 nuclear (nSSR) loci, the genetic composition and diversity of 19 Irish Scots pine populations is described and compared to other European populations. All trees sampled in Ireland were fixed for mitotype a, which is the most common across northwest Europe. By contrast, cpSSR (HCP = 0.967) and nSSR (He = 0.540) variation was high, and comparable with estimates for other regions across the species range. Differentiation at both sets of loci were similarly low (cpSSR FST = 0.019; nSSR FST = 0.018), but populations from continental Europe were significantly differentiated from all Irish populations based on nSSR variation. CONCLUSIONS: All Irish Scots pine are likely part of a common Irish-Scottish gene pool which diverged from continental Scots pine following post-glacial recolonisation. A high genetic diversity and an absence of evidence of inbreeding suggests the regional decline of Scots pine did not critically reduce allelic variation. The post-glacial relationship between Irish and Scottish pine is discussed, and a suggestion from recent palaeoecological work that reintroduced Scots pine be managed as a native species is now further supported by genetic data.

Isolated left ventricular noncompaction as a cause for heart failure and heart transplantation: a single center experience.

OBJECTIVES: To determine the prevalence of isolated left ventricular noncompaction (IVNC) as a cause of heart failure and heart transplantation. METHODS: There were 960 patients seen in the heart failure clinic from 1987 to 2005, with a complete evaluation including echocardiography at our center (study population, 82% men, mean age 52 years). The following data were collected: type of heart disease, age at echocardiography and at heart transplantation, and frequency of heart transplantation. Echocardiographic diagnosis of IVNC was based on our published criteria. RESULTS: The etiologies of heart failure were coronary artery disease (CAD; 37%), idiopathic dilated cardiomyopathy (33%), valvular heart disease (11%), congenital heart disease (5%), IVNC (3%), hypertensive heart disease (3%), hypertrophic cardiomyopathy (2%), myocarditis (1%), and <1% other diagnoses. Heart transplantation was performed in 253 patients (26%) due to idiopathic dilated cardiomyopathy (42%), CAD (39%), valvular heart disease (5%), congenital heart disease (5%), IVNC (2%), or other etiologies (< or =1% each). CONCLUSIONS: The most common causes for heart failure remain idiopathic dilated cardiomyopathy, CAD and valvular heart disease. Strictly using the criteria for the definition of IVNC, IVNC is a rare underlying cardiomyopathy for both, heart failure (2.7%) and heart transplantation (2%) in our center.

Cardiopulmonary fitness predicts postoperative major morbidity after esophagectomy for patients with cancer.

Surgery for radical treatment of esophageal cancer (EC) carries significant inherent risk. The objective identification of patients who are at high risk of complications is of importance. In this study the prognostic value of cardiopulmonary fitness variables (CPF) derived from cardiopulmonary exercise testing (CPET) was assessed in patients undergoing potentially curative surgery for EC within an enhanced recovery program. OC patients underwent preoperative CPET using automated breath-by-breath respiratory gas analysis, with measurements taken during a ramped exercise test on a bicycle. The prognostic value of V˙O2Peak , Anaerobic Threshold (AT) and VE/VCO2 derived from CPET were studied in relation to post-operative morbidity, which was collected prospectively, and overall survival. Consecutive 120 patients were included for analysis (median age 65 years, 100 male, 75 neoadjuvant therapy). Median AT in the cohort developing major morbidity (Clavien-Dindo classification >2) was 10.4 mL/kg/min compared with 11.3 mL/kg/min with no major morbidity (P = 0.048). Median V˙O2Peak in the cohort developing major morbidity was 17.0 mL/kg/min compared with 18.7 mL/kg/min in the cohort (P = 0.009). V˙O2Peak optimum cut-off was 17.0 mL/kg/min (sensitivity 70%, specificity 53%) and for AT was 10.5 mL/kg/min (sensitivity 60%, specificity 44%). Multivariable analysis revealed V˙O2Peak to be the only independent factor to predict major morbidity (OR 0.85, 95% CI 0.75-0.97, P = 0.018). Cumulative survival was associated with operative morbidity severity (χ2  = 4.892, df = 1, P = 0.027). These results indicate that V˙O2Peak as derived from CPET is a significant predictor of major morbidity after oesophagectomy highlighting the physiological importance of cardiopulmonary fitness.

Anderson-Fabry disease: long-term echocardiographic follow-up under enzyme replacement therapy.

AIMS: Anderson-Fabry disease affects various organ systems due to glycosphingolipid accumulation. Enzyme replacement therapy (ERT) has been reported to decrease left ventricular wall thickening (LVWT) and to improve diastolic dysfunction. METHODS AND RESULTS: This prospective study included 29 patients (patients; mean age 37 +/- 13 years) with genetically, enzymatically and/or biopsy-proven Anderson-Fabry disease and long-time ERT. Data on symptoms, cardiac medications and history of hypertension were collected and all patients had comprehensive echocardiographic examination prior to ERT and at follow-up. Disease was at an early stage with a total mean Mainz severity score index of only 18.6 +/- 13.0. Prior to ERT, 79% of patients reported acroparesthesia. The median creatinine level was 121 +/- 108 mcmol/L and LVWT was present in nine patients (31%). Binary appearance of the interventricular septum was found in 20% and posterobasal fibrosis in 83%. At median follow-up of 37 months, acroparesthesia decreased to 55% (P = 0.016). There was no change in creatinine levels. The incidence of LVWT was unchanged, only an increase in interventricular septal wall thickness from 11.7 +/- 0.4 to 12.5 +/- 0.5 was observed (P = 0.009). Left atrial size and the percentage of patients with binary appearance and posterobasal fibrosis were unchanged. There was a small improvement in diastolic function (29% decrease of E/Ea; P < 0.002). CONCLUSION: Our Anderson-Fabry cohort had successful long-time ERT with impressive amelioration of subjective symptoms. Although there was not much improvement in cardiac changes apart from a slight improvement of diastolic function, at least, there was no progression of cardiac disease. For complete reversibility of cardiac changes in Anderson-Fabry disease, ERT might have to be started earlier in life and/or prescribed for a longer time.

Dynamic left ventricular outflow tract obstruction evoked by exercise echocardiography: prevalence and predictive factors in a prospective study.

AIMS: In patients without hypertrophic obstructive cardiomyopathy (HOCM), dynamic left ventricular outflow tract obstruction (DLVOTO) can cause ischaemia. Little is known about incidence and predictors of DLVOTO in patients without HOCM. METHODS AND RESULTS: In 300 patients referred for exercise echocardiography, assessment of DLVOTO at rest and with Valsalva and of the presence of systolic anterior motion of the mitral valve leaflets (SAM) was performed. Within 90 s post-exercise, wall motion, SAM, and DLVOTO were assessed again. A significant DLVOTO was defined as late-peaking Doppler velocity of >or=2.5 m/s (25 mmHg). Excluded were 7 patients with HOCM and 13 with inadequate image quality. There were 280 patients, aged 64(11) years. Coronary artery disease was found in 38% of patients; 44% were receiving beta-blocker therapy and 35% had hypertension. At rest, ejection fraction was 59 +/- 9%; left ventricular hypertrophy (LVH) was present in 21%, SAM in 16%, DLVOTO >or=25 mmHg at rest in 0.7%, and with Valsalva in 3%. At peak, echocardiographic signs of ischaemia occurred in 44%, and significant DLVOTO in 5% (13 patients). By multivariate analysis, it was found that independent predictors of significant DLVOTO at peak were chordal SAM at peak, smaller left ventricle at end-systole, higher systolic blood pressure at peak, younger age and increased septal wall thickness. Significant DLVOTO was a possible cause of symptoms and/or ischaemia in at least 6 of the 13 patients. CONCLUSION: Haemodynamically significant exercise-induced DLVOTO can occur without HOCM. Chordal SAM at peak, small, hyperdynamic left ventricles, increased septal wall thickness, and younger age are the best predictors.

Effect of soluble zinc on differentiation of osteoprogenitor cells.

Amorphous calcium phosphates (ACPs) are attractive fillers for osseous defects and are stabilized through the incorporation of transition metals such as zirconium and zinc. As ACP converts in solution to hydroxyapatite (HAP) in a manner marked by a transient release of calcium and phosphate ions, it is capable of stimulating osteoblastic differentiation. Zinc is known to retard ACP conversion to HAP, and--when incorporated into ceramic biomaterials--has been shown to stimulate osteoblastic differentiation. Because zinc deficiency in vivo is marked by skeletal defects, we postulated that zinc ions released from ACP and other minerals could stimulate proliferation and osteoblastic differentiation of progenitor cells. To test this hypothesis, rat bone marrow stromal cells were cultured in osteogenic medium containing basal (3 x 10(-6) M) or supplemented Zn(2+) concentrations (1 x 10(-5) and 4 x 10(-5) M) for up to 3 weeks. No significant effects of zinc concentration on cell number, alkaline phosphatase activity, total protein content, collagen synthesis, or matrix mineralization were found.

Simple criteria for differentiation of Fabry disease from amyloid heart disease and other causes of left ventricular hypertrophy.

AIMS: Fabry disease may be difficult to differentiate from other causes of left ventricular hypertrophy such as other myocardial storage diseases (including amyloidosis), hypertrophic cardiomyopathy (HCM), or hypertensive heart disease (HHD). We sought to determine simple criteria to best differentiate the above mentioned cardiac diseases. METHODS AND RESULTS: All patients in a six-year time period with left ventricular hypertrophy due to Fabry disease (13 patients), biopsy proven cardiac amyloidosis (16 patients), non-obstructive HCM (17 patients), and 22 randomly selected patients with advanced HHD were compared. Retrospective analysis of clinical characteristics, findings of electrocardiogram (ECG) and echocardiography by blind review was performed. RESULTS: No single clinical characteristic or findings of ECG or echocardiography could reliably differentiate between the various diseases. Increased echogenicity/granular sparkling, valvular abnormalities, abnormal renal function, and diastolic function were not helpful discriminators. In a univariate analysis, four criteria (acroparesthesia, anhydrosis, absence of hypertension and presence of Sokolow criteria for left ventricular hypertrophy in the ECG) were significant for Fabry disease. By logistic regression analysis, the following most suitable discriminative parameters were identified: hypertension in HHD (specificity 82%), orthostasis and/or pericardial effusion for amyloidosis (specificity 93%), papillary muscle anomaly in non-obstructive HCM (specificity 92%), and Fabry disease if neither hypertension orthostatis, pericardial effusion nor a papillary muscle anomaly was present (specificity 87%). CONCLUSION: A combination of symptoms, echocardiographic findings and ECG in unexplained left ventricular hypertrophy may help to differentiate amyloidosis, non-obstructive HCM and hypertensive heart disease from Fabry disease. The results of this preliminary study will have to be confirmed in a prospective study.

WITHDRAWN: Enlargement of the Right Atrium - Diverticulum or Aneurysm?

The publisher regrets that this was an accidental duplication of an article that has already been published in Eur. J. Echocardiogr., 4 (2003) 223-225, . The duplicate article has therefore been withdrawn.

Rush immunotherapy in an experimental model of feline allergic asthma.

Specific allergen immunotherapy represents the only curative treatment of allergy. No studies have evaluated its efficacy in feline allergic asthma. We hypothesized that an abbreviated course of immunotherapy (rush immunotherapy, RIT) would blunt eosinophilic airways inflammation in experimental feline asthma induced with Bermuda grass allergen (BGA). The 6-month study included asthmatic-RIT treated cats; asthmatic-no RIT treated cats; and non-asthmatic cats. RIT involved increasing parenteral doses (20-200 microg) of BGA over 2 days. Numbers of eosinophils in bronchoalveolar lavage fluid (BALF), serum and BALF immunoglobulins, lymphocyte blastogenesis assays, and cytokines in blood and BALF were evaluated. BALF eosinophils decreased (P=0.048) only in asthmatic-RIT treated cats (baseline 1.1 x 10(6); Month 6, 2.4 x 10(5)). Serum BGA-specific IgG was higher (P<0.001) at all time points after baseline within the asthmatic-RIT group, and was higher (P<0.001) than asthmatic-no RIT cats at Months 1 and 3. No differences (P=0.133) in BGA-specific IgE levels over time were noted among asthmatic-RIT cats, but this group had lower IgE levels (P<0.001) levels than asthmatic no-RIT cats at Months 3 and 6. Differences in BGA-specific IgA levels over time and between the two groups did not reach the traditional level of significance. The mean BGA stimulation index in the asthmatic-RIT cats was biologically insignificant at 6 months, reflecting BGA-specific lymphocyte hypoproliferation. Preliminary results of cytokine profiles were not significantly different; however, BAL cytokine profiles favoring a Th2 response prior to RIT shifted to increased IFN-g and IL-10 thereafter. RIT dampens eosinophilic airways inflammation in cats with experimental asthma. The mechanism of RIT may involve changes in allergen-specific immunoglobulins, induction of hyporesponsive lymphocytes, or alteration of cytokine profiles.

Coronary artery dimensions in primary and secondary left ventricular hypertrophy.

BACKGROUND: Coronary artery enlargement has been previously described in left ventricular hypertrophy. OBJECTIVES: We sought to assess coronary artery dimensions and their relation to left ventricular muscle mass in primary and secondary hypertrophy. METHODS: Cross-sectional area of the left and right coronary arteries was determined by quantitative coronary angiography in 52 patients: 12 control subjects and 40 patients (13 with hypertrophic cardiomyopathy, 12 with dilated cardiomyopathy and 15 with aortic valve disease). As a measure of left ventricular hypertrophy, angiographic left ventricular mass and equatorial cross-sectional muscle area were determined. RESULTS: Cross-sectional area of both the left and right coronary arteries is increased in left ventricular hypertrophy (p < 0.05 vs. values in control subjects). There is a curvilinear relation between left coronary artery size and left ventricular muscle mass (r = 0.76) or cross-sectional muscle area (r = 0.75). However, normalization of coronary cross-sectional area for left ventricular muscle mass or muscle area shows insufficient enlargement of the coronary arteries in both primary and secondary hypertrophy. CONCLUSIONS: 1) Coronary artery size increases as left ventricular mass increases in both primary and secondary hypertrophy. 2) The enlargement of left coronary cross-sectional area is independent of the cause of the increase in left ventricular mass. 3) The size of the coronary arteries is inappropriate with regard to left ventricular hypertrophy. Thus, the stimulus for growth of the coronary arteries is not influenced by the underlying disease but appears to depend on the degree of left ventricular hypertrophy.

Quantification of aortic regurgitation with amplitude-weighted mean flow velocity from continuous wave Doppler spectra.

Aortic regurgitant fraction (RFao) was quantified by estimating the ratio of the forward blood flow through the aortic (Qao) and pulmonary (Qp) valve: RFao = 100(Qao - Qp)/Qao. Aortic and pulmonary flow were measured by the systolic time integrals of the amplitude-weighted mean velocity from continuous wave Doppler spectra recorded over the aortic and pulmonary valves. Thus, measurements are independent of the left and right ventricular outflow tract area. In 20 normal subjects, aortic regurgitant fraction ranged between -2.9% and +12.0% (mean +4.3%), the physiologic value being +2%. In 20 patients with pure aortic regurgitation, aortic regurgitant fraction obtained by Doppler spectra (y) was compared with that calculated from biplane left ventriculography and cardiac output determined with the Fick method (x). The correlation was r = 0.94, (SEE = 5.4%, which is 10.6% of the angiography-Fick mean value). The regression line was y = 0.87x + 6.6 (mean y = 51.2%, mean x = 51.1%). It is concluded that determination of aortic regurgitant fraction in pure aortic regurgitation by using the amplitude-weighted mean velocity from continuous wave Doppler spectra is accurate and allows easy noninvasive evaluation of the regurgitant fraction in routine clinical applications.

Long-term follow-up of 34 adults with isolated left ventricular noncompaction: a distinct cardiomyopathy with poor prognosis.

OBJECTIVES: We sought to describe characteristics and outcome in adults with isolated ventricular noncompaction (IVNC). BACKGROUND: Isolated ventricular noncompaction is an unclassified cardiomyopathy due to intrauterine arrest of compaction of the loose interwoven meshwork. Knowledge regarding diagnosis, morbidity and prognosis is limited. METHODS: Echocardiographic criteria for IVNC include-in the absence of significant heart lesions-segmental thickening of the left ventricular myocardial wall consisting of two layers: a thin, compacted epicardial and an extremely thickened endocardial layer with prominent trabeculations and deep recesses. Thirty-four adults (age >16 years, 25 men) fulfilled the diagnostic criteria and were followed prospectively. RESULTS: At diagnosis, mean age was 42 + 17 years, and 12 patients (35%) were in New York Heart Association class III/IV. Left ventricular end-diastolic diameter was 65 + 12 mm and ejection fraction 33 + 13%. Apex and/or midventricular segments of both the inferior and lateral wall were involved in >80% of patients. Follow-up was 44 + 40 months. Major complications were heart failure in 18 patients (53%), thromboembolic events in 8 patients (24%) and ventricular tachycardias in 14 patients (41%). There were 12 deaths: sudden in six, end-stage heart failure in four and other causes in two patients. Four patients underwent heart transplantation. Automated cardioverter/defibrillators were implanted in four patients. CONCLUSIONS: Diagnosis of IVNC by echocardiography using strict criteria is feasible. Its mortality and morbidity are high, including heart failure, thrombo-embolic events and ventricular arrhythmias. Risk stratification includes heart failure therapy, oral anticoagulation, heart transplantation and implantation of an automated defibrillator/cardioverter. As IVNC is a distinct entity, its classification as a specific cardiomyopathy seems to be more appropriate.

Congenital cleft of the anterior tricuspid leaflet with severe tricuspid regurgitation in adults.

OBJECTIVES AND BACKGROUND: Severe primary tricuspid regurgitation in the adult is a rare finding. This study describes the diagnostic findings and the treatment of an isolated congenital cleft of the anterior leaflet of the tricuspid valve as the morphologic substrate for severe tricuspid regurgitation. METHODS: The clinical, echocardiographic findings and the follow-up findings of five patients (all male, 20 to 56 years old) with this disorder are described. Four of the five patients underwent cardiac surgery that confirmed the diagnosis. RESULTS: In three of five patients, exertional fatigue was the limiting symptom (New York Heart Association functional classes II and III). The clinical findings included a holosystolic murmur and supraventricular arrhythmias in all patients. Cardiac catheterization, performed in four patients, yielded the incorrect diagnosis of Ebstein's anomaly in three. In one patient the cleft was associated with an atrial septal defect of the secundum type. In four of five patients successful reconstruction of the tricuspid valve with a DeVega annuloplasty was performed. One patient had a partial excision of the right atrium, and one had a closure of a coexisting atrial septal defect. One patient refused operation. CONCLUSIONS: Tricuspid valve anomalies can be accurately identified by Doppler echocardiography. Surgical repair is the treatment of choice in patients with severe tricuspid regurgitation due to a congenital cleft of the anterior leaflet of the tricuspid valve.

Long-term follow-up of medical versus surgical therapy for hypertrophic cardiomyopathy: a retrospective study.

In a retrospective analysis 139 patients with hypertrophic cardiomyopathy were followed up for 8.9 years (range 1 to 28 years). Patients were divided into two groups: Group 1 consisted of 60 patients with medical therapy and Group 2 of 79 patients with surgical therapy (septal myectomy). Groups 1 and 2 were subdivided according to the medical treatment. Group 1a received propranolol, 160 mg/day (n = 20); Group 1b verapamil, 360 mg/day (n = 18); and Group 1c, no therapy (n = 22). Group 2a received verapamil, 120 to 360 mg/day, after septal myectomy (n = 17) and Group 2b had no medical therapy after surgery (n = 62). In Group 1, 19 patients died (annual mortality rate 3.6%) and in Group 2, 17 patients died (mortality rate 2.4%, p = NS). Of the patients who died, approximately one half to two thirds in both Groups 1 and 2 died suddenly and the other one half to one third died because of congestive heart failure. The 10 year cumulative survival rate was 67% in Group 1, significantly smaller than that in Group 2 (84%, p less than 0.05). In the subgroups, the 10 year survival rate was 67% in Group 1a, 80% in 1b (p less than 0.05 versus 1a) and 65% in 1c (p less than 0.05 versus 1b). The 10 year survival rate was 100% in Group 2a (p less than 0.05 versus 1a, 1b, 1c) and 78% in Group 2b (p less than 0.05 versus 2a). It is concluded that cumulative survival rate is significantly better in surgically than in medically treated patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of drug treatment on inflammation and hyperreactivity of airways and on immune variables in cats with experimentally induced asthma.

OBJECTIVE: To compare the effects of an orally administered corticosteroid (prednisone), an inhaled corticosteroid (flunisolide), a leukotriene-receptor antagonist (zafirlukast), an antiserotonergic drug (cyproheptadine), and a control substance on the asthmatic phenotype in cats with experimentally induced asthma. ANIMALS: 6 cats with asthma experimentally induced by the use of Bermuda grass allergen (BGA). PROCEDURES: A randomized, crossover design was used to assess changes in the percentage of eosinophils in bronchoalveolar lavage fluid (BALF); airway hyperresponsiveness; blood lymphocyte phenotype determined by use of flow cytometry; and serum and BALF content of BGA-specific IgE, IgG, and IgA determined by use of ELISAs. RESULTS: Mean +/- SE eosinophil percentages in BALF when cats were administered prednisone (5.0 +/- 2.3%) and flunisolide (2.5 +/- 1.7%) were significantly lower than for the control treatment (33.7 +/- 11.1%). We did not detect significant differences in airway hyperresponsiveness or lymphocyte surface markers among treatments. Content of BGA-specific IgE in serum was significantly lower when cats were treated with prednisone (25.5 +/- 5.4%), compared with values for the control treatment (63.6 +/- 12.9%); no other significant differences were observed in content of BGA-specific immunoglobulins among treatments. CONCLUSIONS AND CLINICAL RELEVANCE: Orally administered and inhaled corticosteroids decreased eosinophilic inflammation in airways of cats with experimentally induced asthma. Only oral administration of prednisone decreased the content of BGA-specific IgE in serum; no other significant local or systemic immunologic effects were detected among treatments. Inhaled corticosteroids can be considered as an alternate method for decreasing airway inflammation in cats with asthma.

Left ventricular systolic series elastic properties in aortic stenosis before and after valve replacement.

In seven patients with aortic valve disease the time course of an auxotonic beat was compared with that of an isovolumetric beat produced by aortic cross clamping during open heart surgery. The rate of systolic stress rise (dS/dt; g.cm-2) of the isovolumetric beat at peak meridional wall stress (Sp; g.cm-2) of the auxotonic beat was determined by tipmanometry and simultaneous sonomicrometry and was found to be 87% of maximum dS/dt. In the second part of the study the stiffness index (k) was calculated in patients undergoing cardiac catheterisation according to: k = 0.87.(max.dS/dt)/Sp.Vcf, where Vcf = normalised midwall circumferential fibre shortening velocity (circ.s-1). In 22 patients, 10 controls and 12 patients with aortic stenosis before (pre) and after (post) valve replacement the systolic stiffness index k (circ-1) was determined using tipmanometry and frame by frame angiocardiography. Muscle fibre diameter and interstitial fibrosis were assessed from left ventricular endomyocardial biopsies. The systolic stiffness index k was 15 circ-1 in controls, 14 in preoperative patients with aortic stenosis and 12 (p less than 0.01 v controls) in postoperative patients. There was a significant correlation between k and muscle fibre diameter (r = 0.55; p less than 0.01) but not between k and interstitial fibrosis or ejection fraction. We conclude that systolic stiffness index k is normal despite marked left ventricular hypertrophy in preoperative patients with aortic stenosis. Following successful valve replacement systolic stiffness index decreased and was significantly lower than in controls. Series elasticity appears to be determined by structures related to the muscle cell rather than to interstitial fibrosis.

Cardiovascular and metabolic effects of insulin-like growth factor I at rest and during exercise in humans.

To determine whether insulin-like growth factor I (IGF-I) has systemic cardiovascular effects in humans, 60 micrograms/kg IGF-I or saline were injected sc in a cross-over, randomized, double blind fashion into eight healthy male volunteers. Cardiac function and performance were evaluated by echocardiography and exercise test. In parallel, the metabolic effects of IGF-I during exercise were investigated. IGF-I improved cardiac performance with a significant increase in stroke volume and cardiac output by 14% and 18% (P < 0.03 and P < 0.04), respectively. Ejection fraction increased by 9% after IGF-I treatment (P < 0.05). Heart rate was not significantly increased at rest or during exercise. Systolic blood pressure was slightly increased by IGF-I, whereas diastolic blood pressure was slightly decreased, resulting in a continuous increase in the blood pressure amplitude at rest and during exercise, but without reaching statistical significance. Maximal exercise duration and peak oxygen consumption were not changed. Exercise was uneventful, without pathological changes on electrocardiogram records. Glucose levels were unchanged, whereas insulin and C peptide levels were decreased by IGF-I at rest. During exercise, insulin levels were further decreased, and the insulin-sparing effect of exercise resulted in a further enhancement of tissue sensitivity to insulin. GH levels were suppressed by IGF-I treatment at rest, but were still stimulated by exercise. In conclusion, IGF-I has positive inotropic effects in man. Further investigation of the potential role of IGF-I in cardiac conditions such as heart failure appears to be warranted.

Sequence of the putative alanine racemase operon in Staphylococcus aureus: insertional interruption of this operon reduces D-alanine substitution of lipoteichoic acid and autolysis.

A gene cluster comprising the alanine racemase gene alr was identified 5' to the sigB operon in Staphylococcus aureus. It is flanked upstream by four ORFs of which one shows similarity to the dpj gene of Escherichia coli, and downstream by two ORFs of which the last shows similarity to the E. coli pemK gene. Preliminary data suggest that the seven ORFs orf1-orf2-orf3-dpj-alr-orf6-pemK may form an operon. Disruption of the proposed operon by insertional mutagenesis leads to a drastic loss in the d-alanine (d-Ala) substitution of lipoteichoic acid and to delayed autolysis, without affecting the d-Ala substitution of the wall teichoic acid.