Comparison of the Ca2+ complexing properties of isosaccharinate and gluconate - is gluconate a reliable structural and functional model of isosaccharinate?

The calcium complexation and acid-base properties of α-d-isosaccharinate (Isa-) in neutral and in (hyper)alkaline solutions have been investigated via potentiometric titrations, multinuclear NMR, ESI-MS and quantum chemical calculations. Isa- is the primary alkaline degradation product of cellulose, and may be present in radioactive waste repositories and therefore, it could contribute to the mobilization of radioactive nuclei. Because of its limited availability, d-gluconate (Gluc-) is commonly used as a structural and functional model of Isa-. Therefore, the thermodynamic and structural data obtained for Isa- were compared with those of Gluc-. The formation constants of the CaIsa+ and CaGluc+ complexes present in neutral solutions are practically identical, but the binding sites are in different positions and the CaIsa20 solution species cannot be detected. The stepwise formation constant of the CaIsaH-10 complex (forming in alkaline medium) is somewhat larger than that of CaGlucH-10, which is in line with the observation that IsaH-12- is a stronger base than GlucH-12-. The most striking difference is that, unlike Gluc-, Isa- does not form polynuclear complexes with Ca2+. The structural reason for this is that the alcoholate groups on C2 and C3 adjacent to the carboxylate moiety on Gluc- are able to simultaneously bind Ca2+, making the formation of polynuclear Ca-complexes possible. On Isa-, only the alcoholate on C2 is involved, while the other one on C6 is not (supposedly for steric reasons). In conclusion, during the interactions of Gluc- and Isa- with Ca2+, differences rather than similarities prevail.

Isolation and activity of Xenorhabdus antimicrobial compounds against the plant pathogens Erwinia amylovora and Phytophthora nicotianae.

AIMS: Broad-spectrum antibiotics produced by symbiotic bacteria [entomopathogenic bacterium (EPB)] of entomopathogenic nematodes keep monoxenic conditions in insect cadavers in soil. This study evaluated antibiotics produced by EPB for their potential to control plant pathogenic bacteria and oomycetes. METHODS AND RESULTS: Entomopathogenic bacterium produce antibiotics effective against the fire blight bacterium Erwinia amylovora, including streptomycin resistant strains, and were as effective in phytotron experiments as kasugamycin or streptomycin. Xenorhabdus budapestensis and X. szentirmaii antibiotics inhibited colony formation and mycelial growth of Phytophthora nicotianae. From X. budapestensis, an arginine-rich fraction (bicornutin) was adsorbed by Amberlite((R)) XAD 1180, and eluted with methanol : 1 n HCI (99 : 1). Bicornutin inactivated zoospores, and inhibited germination and colony formation of cystospores at <<25 ppm. An UV-active molecule (bicornutin-A, MW = 826), separated by HPLC and thin-layer chromatography, was identified as a novel hexa-peptide : RLRRRX. CONCLUSIONS: Xenorhabdus budapestensis produces metabolites with strong antibacterial and cytotoxic activity. Individual compounds can be isolated, identified and patented, but their full antimicrobial potential may be multiplied by synergic interactions. SIGNIFICANCE AND IMPACT OF THE STUDY: Active compounds of two new Xenorhabdus species might control plant diseases caused by pathogens of great importance to agriculture such as Erw. amylovora and P. nicotianae.

Xenorhabdus antibiotics: a comparative analysis and potential utility for controlling mastitis caused by bacteria.

AIMS: The role of antibiotics produced by bacterial symbionts of entomopathogenic nematodes is to suppress growth of microbes in the soil environment. These antibiotics are active against Gram-positive and Gram-negative bacteria, and were tested against mastitis isolates from dairy cows. METHODS AND RESULTS: Two bioassays were adapted for Xenorhabdus antibiotics; an overlay method on agar plates, and serially diluted, cell-free, Xenorhabdus cultures. The antimicrobial activities of the liquid cultures of 13 strains from five Xenorhabdus species were further evaluated. Antimicrobial activities of the type strains of X. nematophila, X. budapestensis and X. szentirmaii were tested on mastitis isolates of Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae with both bioassays. A previously reported antibiotic from X. nematophila, nematophin, was synthesized in three steps from tryptamine and 4-methyl-2-oxovaleric acid sodium salt. CONCLUSIONS: The antibiotics of all three Xenorhabdus strains were powerful in either bioassay, but the sensitivity of the isolates differed from each other. While Kl. pneumoniae was the least susceptible, Staph. aureus had the highest sensitivity to each Xenorhabdus strain. Xenorhabdus szentirmaii and X. budapestensis were more potent antibiotic producers than X. nematophila, and raceme nematophin was ineffective against all mastitis isolates. SIGNIFICANCE AND IMPACT OF THE STUDY: These results indicate that Xenorhabdus antibiotics are effective against mastitis isolates and should be further evaluated for their potential in mastitis control or prevention.

Effect of tensiomin in ischaemic dilatative cardiomyopathy.

The effect of the angiotensin-converting enzyme inhibitor, Tensiomin, has been examined in patients suffering from ischaemic dilatative cardiomyopathy who had become unresponsive to combined vasodilatator--diuretic--digitalis therapy. The results were evaluated according to the changes in NYHA classes and echocardiographic parameters. Significant improvement was observed in response to Tensiomin in 38 of the 52 patients (73%). On the basis of the results the use of captopril (Tensiomin) is highly recommended for the treatment of ischaemic dilatative cardiomyopathy.

99-m technetium (Dupont Cardiolite) investigations in postinfarction patients with Holter-checked silent ischaemia.

Sixteen middle-aged, normotensive, slightly overweight male patients with previous myocardial infarction were studied during Holter-checked silent myocardial ischaemia. As reference, stress and late 201-T1 scintigraphy served for comparison with Cardiolite-MIBI silent ischaemic perfusion scan, both carried out in planar mode. The circumferential profiles differed in 9 cases, on region of interest basis the segment number difference was 10, but the late distribution segment number was near to both ischaemic numbers. The quantitative scores were distinctive (ratio 133-128/103) indicating the silent ischaemia appeared in the peri-infarct area. The silent ischaemic MIBI and stress 201-T1 ischaemic score difference was reduced by means of repeated SPECT investigation. With gated radionuclide ventriculography there was -4.3% difference between the left ventricular ejection fractions, measured with first pass MIBI technique during silent ischaemia and afterwards in basal state. The impairment of the left ventricular function was reflected on the stroke pattern of our Holter-based radiocyclogram, as well. Taking the 43.7-48.0 = -4.3% "ischaemic shift" into consideration it was a close correlation (r = 0.90) between the two kinds of ejection fraction determination. The major rhythm failures (occurring during the 24 h Holter monitoring) decreased to a higher degree the left ventricular ejection fraction than silent ischaemia or silent ischaemia and minor rhythm failure together (38-42-50%).

Nonfatal myocardial infarction of women.

Five-hundred women admitted for rehabilitation to the State Hospital for Cardiology 1 to 10 months after myocardial infarction were divided into two groups, viz. group I containing patients less than 40 years of age and group II, in which the patients were older than 41 years. Forty-nine per cent of the patients were blue-collar, whereas 22% of them were white-collar workers; 16.5% had a high qualification, 28% were housewives or retired. The leading symptom at admittance, that is in the post-infarction period, was angina pectoris (32% in group I and 73% in group II). Heart failure, rhythm disturbance and hypertension occurred less frequently. The groups considerably differed from each other in the frequency of risk factors. In group I, smoking (81%), use of anticoncipients (41%) and hyperlipoproteinaemia (32%), while in group II hypertension (49%), smoking (45%), obesity (43%) and hyperlipoproteinaemia (41%) were the main risk factors.

111-indium human antimyosin monoclonal antibody-fragment study on alcoholic (and diabetic) cardiomyopathic patients (ACM-DCM) with Centocor Europe Myoscint (Msc).

The criteria of Msc-positivity were: typical accumulation of hot spots in 2 directions of planar scan in the 24-48-hr measurements, while in atypical cases the hot spots were present only in the 48 hr picture. Twenty-one male volunteers were assessed. 18 of them had ACM (2 patients were studied repeatedly). The negative and positive control cases exhibited the expected Msc pattern. Seven ACM patients were regarded typically positive, in 5 cases atypical positivity was stated, and 6 patients were classified as Msc negatives. The heart lung activity ratio was 1.75 +/- 0.45 and 1.68 +/- 0.44 for typical and atypical positive cases, respectively. The control and DCM H/L ratios were 1.15 and 1.3 +/- 0.2, respectively, in AMI the H/L was 1.91, in DCM of dilatative phase it was 1.55 +/- 0.06 with serum myosin in the normal range. Heart dilation in the DCM groups: 5 dilated out of 7 typically positive cases while in atypically positive, and negative cases the dilation occurred in 2 out of 5 and 1 out of 6 cases, respectively. Low LV-EF (less than 45%) were found in ratios of 4/7, 2/5, and 1/6 in typically positive, atypically positive and negative cases, respectively. Elevated PCP similar ratios. In the same groups pathological ECG was seen in ratios of 5/7, 1/5, and 1/6, respectively. The g-GT activity was enhanced in all cases, there was, however, no evident correlation between the actual enzyme activity and intensity of hot accumulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Circulatory disturbances of the venous system of the legs after coronary bypass graft operation.

The alterations of 85 limbs of 69 patients were examined after aortocoronary bypass operation. The study was partly retrospective, partly prospective. The limbs were divided into two groups according to their severity grade. On 36 legs (42%) the site of operation was free of reaction (inflammation, oedema). Twenty-seven legs (32%) required treatment with diuretics and Venoruton (success rate, 89%). Because of alterations of 22 legs (26%) Venoruton, Glyvenol, Colfarit, intravenous Rheomacrodex and, at the site of the intervention, heparin were administered. The inflammation of 4 of the 22 legs required, besides these treatments, antibiotics. Amelioration was observed in 20 of the 22 legs. The authors call attention to a new type of venous circulatory disturbances which may be iatrogenic in some respect. It would be possible to prevent a considerable part of the alterations if heart-surgeons, in cooperation with the peripheral vessel specialists, made additional examinations before operation. The treatment of the venous circulatory disturbance should already be started at the surgical centers and continued during after-care.

Pathophysiological significance of the global and regional left-ventricular ejection fraction (LV-EF) on ischaemic heart disease patients at rest and during ergometric exercise load (from radiocardio-cyclography (RKG-RCG) to parametric amplitude and phase scan).

As early as in the graphical RKG-RCG period a close inverse correlation could be established between the LV-EF and the serum myoglobin level during the acute course of myocardial infarction, in 10 patients in repeated follow up examinations. Corr. coeff. -0.91, p less than 0.01. In the mid seventies it could be shown by RKG-RCG, in 15 IHD patients with angina pectoris that the decrease of the basal LV-EF during ergometric load reflected the severity of IHD, compared with the increasing LV-EF tendency of 15 normal subjects. This fact could be verified on 19 middle age males (mean age, 41 years) by 99mTc RBC gamma camera ventriculography, i.e. that under modest load (100 W ergometry) a more than 10% decrease was a non-specific sign of main branch or three-vessel coronary heart disease. So in this extreme case our nuclear stethoscope-like RKG-RCG method alone may be satisfactory for staging and screening of coronary ischaemic heart disease (IHD) patients. All the 11 normal subjects belonged to the load-reaction group with more than 5% LV-EF increase, while the extensive anterior and inferior scar patients reacted without exception with more than 10% deficit (their basal LV-EF value was already under 45%). Supported by data in the literature in the comparison of load ECG and coronarography and two-step load, we could gain more refined data, but in accordance with the one-step load on the same patients. As regards the reproducibility of our global LV-EF investigations with gamma camera computer program Supersegams, it was within 5%.(ABSTRACT TRUNCATED AT 250 WORDS)

123-Iodine heptadecanoic acid (HDA) cardiac metabolism of inactive sportsmen with nuclear cardiology, impacted into complex cardiological studies.

In 8 sportsmen and 8 healthy subjects of similar middle age the examination of the myocardial uptake of 123-I HDA and 201-T1 exhibited a correlation of r = 0.88 using our own quantitative circumferential evaluation program. The myocardial kinetics of the 123-I HDA was assessed by different methods: 1. according to Feinendegen et al. (1981), with complementary NaI-123 injection for the extra-myocardial background correction, 2. according to Dudczak (1984), with bi-exponential peeling, similar to the simplified method of the van Eenige group (1984, 1985). The utilisation-elimination kinetics resulted in comparable results with correlation coefficients of r = 0.80 and they were in accordance with the literature data; so this examination can be carried out without surplus NaI-123 injection, as well. The only significant difference was observed in some sportsmen who, after discontinuing the competitions, had a minimal delay of the HDA-kinetics in the septal region, where the echo-CG registered septal hypertrophy, as well. Otherwise the data of the HDA-kinetics, of the 201-T1 uptake and wash-out redistribution were in agreement with the results of the global and regional left ventricular ejection fractions, with the ECG at rest and during ergometric stress with the mechano-CG and with the cardio-volumetry, all exhibiting overlaps in the normal range between the sportsmen and healthy controls.

Quantitative evaluation of exercise-induced ST-segment depression for estimation of degree of coronary artery disease.

Comparative analysis of coronary arteriography and exercise ECG recordings of 33 patients with ischaemic heart disease is presented. Linear regression was found between the increase of heart rate (HR) as well as increase of systolic blood pressure-heart rate product (SBP X HR) and the level of ST-segment depression developing during exercise. A significant correlation was established between the slope of the regression line (i.e. 'm' coefficient of y = mx + b) expressing the rate of change of ST-segment depression and the degree of coronary artery disease confirmed by arteriography. The average value of 'm' coefficients differed significantly according to the number of diseased vessels (P less than 0.01-0.001). The ratio of maximal ST depression and maximal HR (STmax/HRmax) measured at the end of the exercise indicated reliably the severity of coronary artery disease and is suggested for everyday practice.

[Comparison of institutional and ambulatory methods of rehabilitation in myocardial infarct]. / Vergleich der Instituts- und Ambulanzform der Rehabilitation nach Myokardinfarkt.

The authors compared the results of their own methods of rehabilitation after myocardial infarction, applied in two groups: 92 patients who were trained in the institute, and in other 92 patients who performed their rehabilitation training for some weeks at home. In all patients the working capacity (bicycle ergometry), psychosocial state and rate of return into professional activity over one year after infarction were examined. No statistically significant differences in the results obtained in both groups were found except for the working capacity, the improvement of which was significantly more pronounced in patients who performed their rehabilitation training in the institute.