Diffusivity of myoglobin in intact skeletal muscle cells

We report a method that allows us to determine the diffusion coefficient of native myoglobin in intact and mechanically unaffected red muscle fibers. The method is based on an optical recording of intracellular diffusion of metmyoglobin, which is produced inside the cells by photooxidation of oxymyoglobin with a UV light pulse. We find a myoglobin diffusivity of 1.2 x 10(-7) cm2/s (22 degrees C), which is only 1/10th of the value measured in very dilute myoglobin solutions and 1/5th of the value obtained from measurements in solutions of myoglobin at 18 g/dl. The latter value often has been used in model calculations of oxygen transport to tissue incorporating myoglobin-facilitated oxygen diffusion. Recalculating facilitated diffusion with the value obtained by us implies that its contribution to total intracellular oxygen transport is of minor importance. Furthermore, it shows that sterical hindrance to myoglobin diffusion is dominated by the muscle-cell architecture rather than by the overall protein concentration of the muscle fiber.

Antibodies and viremia in acute post-transfusion hepatitis C: a prospective study

Fourteen patients who developed acute post-transfusion hepatitis C after open-heart surgery were studied for seroconversion, viremia, and aminotransferase. Anti-HCV antibodies were measured by first and second generation ELISA and became positive between one week and more than 6 months after infection. Seroconversion in four patients and passively transfused antibodies were only found by the second generation assay, indicating its significantly higher sensitivity. Viremia was detected by reverse transcription and the polymerase chain reaction within the first 4 weeks of infection in 13 patients and persisted for more than 2 years in all of them. One patient died of cardiac cause. Viral strains were heterogeneous between the different patients, but showed no significant variation within one patient during the course of hepatitis deduced from the results with different sets of oligonucleotides. Viremia preceded hepatitis by 4 weeks, seroconversion determined by ELISA II followed after an 8 week interval, and anti-C-100 antibodies appeared 26 weeks later. Aminotransferase activities returned to normal values in 10 patients.

Elastosis and cancer

Recently we have shown that the autofluorescence within or just outside of a malignant tumor is rather small or large resp. in comparison to healthy tissue when excited at 365 nm. Studies with unfixed, unstained cryosections of skin with melanomas have revealed bulky fiber-like structures with a high fluorescence intensity just outside of a malignant tumor. Using polarized light, the structures could be identified as elastic fibers. This was also confirmed by studies on arterial walls.

A table-mounted stereotactic system for digital angiography: a means of standardizing arteriovenous malformation measurement

A detachable noninvasive table-mounted stereotactic device is described for use with digital radiography. The device is designed for standard two-view orthogonal projections but may be adjusted to allow for projections angled from the axial plane. When applied to the imaging of arteriovenous malformations (AVMs), it negates the influence of a variety of geometric and mechanical factors which would otherwise interfere with the determination of size. An accurate appreciation of AVM size, in turn, would allow a more reliable means of categorization of AVMs into distinctive groups for classification purposes and prognostication.

A study of the percutaneous absorption-enhancing effects of cyclodextrin derivatives in rats

2-Hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) and 2,6-dimethyl-beta-cyclodextrin (D-beta-CyD) were studied for transdermal penetration enhancement of the cytochrome P450 inhibitor liarozole by an in vivo transdermal absorption rat model. The mode of action of penetration enhancement was investigated by differential scanning calorimetry (DSC). In-vivo, HP-beta-CyD, as a 20% aqueous solution, increased the absorption of liarozole approximately threefold and a 20% aqueous solution of D-beta-CyD decreased the percutaneous absorption of liarozole in blood by a factor of 0.6. However, pretreatment with D-beta-CyD (20%, 4 h) enhanced the transdermal absorption 9.4-fold. In the DSC experiments the thermal profile of human stratum corneum was practically unchanged after treatment with HP-beta-CyD, but treatment with D-beta-CyD revealed an interaction of D-beta-CyD with the protein and lipid fraction. Thus the results from DSC and those from the permeability experiments revealed that D-beta-CyD acts as a transdermal absorption enhancer by changing the stratum corneum barrier whereas HP-beta-CyD influences the partitioning behaviour of the drug in the skin.

Assessing glycosidic linkage flexibility: conformational analysis of the repeating trisaccharide unit of Aeromonas salmonicida

A detailed conformational analysis was performed for the synthetic branched trisaccharide beta-D-ManNAc-(1-->4)-[alpha-D-Glc-(1-->3)]-L-Rha 1 which represents the repeating unit of the O-antigenic polysaccharide of Aeromonas salmonicida. The study was based on 26 experimental NOE curves from 1D transient NOE experiments, employing Gaussian-shaped inversion pulses at 600 MHz. Eight of the NOE curves were interglycosidic and thus useful for an analysis of glycosidic linkage orientations. Metropolis Monte Carlo (MMC) simulations and minimum-energy calculations with the program GEGOP were used to obtain theoretical NOE curves which were compared to the experimental ones. MMC simulations with different temperature parameters of 310, 600, 900 and 2000 K allowed identification of NOEs which are sensitive towards different conformation distributions--not only different conformations--at both glycosidic linkages in 1. A comparison of trisaccharide 1 with the constituent disaccharides beta-D-ManNAc-(1-->4)-L-Rha 2 and alpha-D-Glc-(1-->3)-L-Rha 3 revealed effects of branching on glycosidic linkage flexibility. A quantitative evaluation was facilitated by the introduction of entropy-related flexibility parameters. Our study indicates a notable restriction of flexibility, especially at the (1-->3) linkage in 1. Although overall flexibility in 1 is reduced as compared to the constituent disaccharides 2 and 3, it cannot be neglected altogether. In summary, combined transient NOE experiments and MMC simulations provide a simple approach to analyse glycosidic linkage flexibility.

Atrophy of mesial structures in patients with temporal lobe epilepsy: cause or consequence of repeated seizures?

We studied 70 epileptic patients by using magnetic resonance imaging volumetric measurements of amygdala (AM) and hippocampal formation (HF). Fifty patients presented with intractable temporal lobe epilepsy (TLE), 10 patients had focal extratemporal lobe epilepsy, and 10 had generalized epilepsy. In 91% of the 45 TLE patients without foreign tissue lesions, there was significant smallness of the AM and/or HF coinciding with the side of electroencephalographic seizure onset. No significant smallness or asymmetry was demonstrated in patients with focal extratemporal or generalized epilepsy. We performed a linear regression analysis, plotting the number of years of recurrent seizures and the estimated seizure frequency against the volumes of the AM and HF. There was no correlation between either of these two parameters and AM or HF volume (p > 0.9). There was also no correlation between the patient's age and volumetric measurements of AM or HF, nor did these measurements correlate with the occurrence of generalized seizures. On the other hand, patients with antecedent prolonged febrile convulsions in early childhood had significantly smaller AM and HF, compared with those without such a history (p < 0.001). The findings indicate that repeated seizures or longer duration of epilepsy do not cause increased atrophy of AM or HF that is measurable by volumetric magnetic resonance imaging.

Drug abuse emergencies in Hamburg 1990/91

During a 30-month investigation of the prevalence and structure of drug emergencies in Hamburg, data from all ambulances were analysed. From January 1991 to June 1992 there were 1565 drug-related emergency patients suffering a life-threatening event in Hamburg (1097 male, 350 female, 118 without information concerning the sex) to whom medical care was given by an emergency team. The number of cases grew strongly from 538 in 1990 to 720 in 1991. The place where the patients were found was very often in the region around the main railway station and near to the Reeperbahn, but we could also observe a scene south of the river Elbe.

Comparison of drug abuse fatalities and emergencies

During a 9-month period, drug abuse emergencies were investigated prospectively and compared with drug-related fatalities of the same period. The emergency patients were of younger age, the proportion of women and the prevalence of infections with HIV, HBV and HCV was higher than in drug-related deaths. Additional alcohol consumption was similar in both groups but more frequent in drug-addict emergencies where the patients were 20-30 years of age. It is suggested that the emergency patients might characterise a special risk group of drug addicts and might be a target for interventional help to prevent fatalities.

Interference of N-(1-[4-(4-fluorophenoxy)butyl]-piperidinyl)-N-methyl- 2-benzothiazolamine with Na+/H+ exchange and Na+/Ca2+ exchange in purified cardiac sarcolemmal membranes

The effect of R 56865 (N-[1-[4-(4-fluorophenoxy)butyl]-piperidinyl]-N-methyl-2- benzothiazolamine, CAS 104606-13-5) on Na+/H+ exchange and Na+/Ca2+ exchange was studied in isolated cardiac sarcolemmal vesicles. R 56865 inhibited Na+/H+ exchange with an ED50 of 180 mumol/l at a concentration of 0.05 mmol/l Na+. The potency of R 56865 decreased with increasing concentrations of Na+. Na+/Ca2+ exchange was also inhibited. The ED50 amounted to 45 mumol/l. This ED50 was close to that of the reference compound dichlorobenzamil (ED50 = 27 mumol/l). The inhibitory potency of R 56865 on Na+/H+ and Na+/Ca2+ exchange is far too low to explain the already reported beneficial effects of this inhibitor of Na+ and Ca+ overload during ouabain intoxication and ischemia and reperfusion.

Sequence analysis of hepatitis B virus DNA in immunologically negative infection

It was previously demonstrated that the serum of some patients without immunological evidence of HBV infection contains the virus. Here we demonstrated by sequence analysis that the serum of such a patient contained a mixed HBV population. In comparison with HBV genomes of different genotypes twenty-two nucleotide variations were found in all clones sequenced in parallel. One nucleotide variation was identified within the enhancer I. Twelve of the twenty-two nucleotide variations caused altogether fifteen changes of amino acid sequence in known or predicted viral proteins. The proteins of the P open reading frame, which are most important for viral replication, were affected by nine amino acid substitutions. Three amino acid substitutions concerned the product of the X gene, a transcriptional transactivator of various viral and cellular promoters. Three mutations were only observed in some of the clones. One point mutation affected the direct repeats of the enhancer II. It occurred together with an 8 bp-deletion involving the C promoter region and the X gene. The third mutation was a single insertion, causing a fusion of the X and C gene. One or several of the identified mutations could be responsible for the diminished rate of replication and consequently for the low-titred, immunologically negative HBV infection.

Conformational analysis of alpha-D-Fuc-(1-->4)-beta-D-GlcNAc-OMe. One-dimensional transient NOE experiments and Metropolis Monte Carlo simulations

One-dimensional transient NOE build-up curves were measured for the synthetic disaccharide alpha-D-Fuc-(1-->4)-beta-D-GlcNAc 1 utilizing Gaussian shaped pulses. Simulated build-up curves from Metropolis Monte Carlo simulations were compared to the experimental data. Disaccharide 1 is structurally related to methyl beta-D-maltoside in that it also contains an alpha-(1-->4) linkage, and it has the same configuration of groups around the glycosidic linkage. Analysis of NOEs in methyl beta-D-maltoside is restricted to those observed upon selective excitation of H1' because of severe spectral overlap. The situation is different in 1 where 1H-NMR signals are well separated. Several interglycosidic NOEs were observed. The corresponding build-up curves allowed an accurate determination of the conformational preferences at the glycosidic linkage in 1. Comparison of experimental and theoretical NOE build-up curves showed clearly that rigid minimum-energy models cannot account for the experimental data. The best fit of experimental NOE build-up curves was obtained with theoretical curves from a 2 x 10(6) step Metropolis Monte Carlo simulation with the temperature parameter set at 1000 K. Finally, it was observed that only the interglycosidic NOE H5'/H6-pro-S significantly depends upon varying conformation distributions at the alpha-(1-->4)-glycosidic linkage, induced by choosing different temperature parameters for the Metropolis Monte Carlo simulations.

An improved model for studies on transdermal drug absorption in-vivo in rats

In rats, transdermal drug absorption can be studied under physiological conditions by cannulating the peripheral skin vein, draining the are of the skin which is used for drug application, and collecting the blood. This method leads to decreased blood volume, which causes a reduction in skin blood flow and limits the maximal duration of the experiment. We improved the model by replacing the collected blood with blood from donor animals, so enabling the measurement of transdermal absorption over a period of 5 h under near constant conditions of blood pressure, haematocrit and skin blood flow. The model was applied to the transdermal absorption of [3H]prazosin and [3H]scopolamine and their permeability coefficients, fluxes and lag-times were determined. The model is suitable for measurements of transdermal drug absorption under in-vivo conditions, both for comparison of absorption profiles of different drugs and of the same drug in different formulations.

MRI volumetric measurement of amygdala and hippocampus in temporal lobe epilepsy

We performed MRI volumetric measurements of the amygdala (AM), the hippocampal formation (HF), and the anterior temporal lobe in a group of 30 patients with intractable temporal lobe epilepsy (TLE) and in seven patients with extratemporal lobe foci. Measurements were analyzed with a semiautomated software program and the results compared with those of normal controls and correlated with the findings of all other investigations. In particular, we compared the results with the lateralization of epileptic abnormalities in the EEG. Volumetric studies of AM and HF showed lateralization of measurable atrophy consistent with that derived from extracranial and intracranial EEG examinations. The HF volumes were more sensitive and provided a lateralization in 87%. Combined measurements of AM and HF showed lateralization in 93%, always congruent with the results of EEG lateralization. This slight but important additional improvement in discrimination justifies using AM measurements in MRI volumetric studies of mesial temporal structures. Volumetric studies combined with other currently employed noninvasive techniques may diminish the need for invasive methods of investigation in patients with TLE.

MRI of amygdala and hippocampus in temporal lobe epilepsy

In this study we compared the results of qualitative visual analysis of MRI with volumetric studies of the amygdala (AM) and hippocampal formation (HF) in a group of 31 patients. Twenty-six patients with temporal lobe epilepsy (TLE) and six with non-TLE had MRI studies using a 1.5 T Gyroscan following a specific protocol for scan acquisition. The MR images were interpreted by two blinded radiologists and by a third if discrepancy arose. Volumetric studies were carried out by one or two raters. The volumetric measurements of AM and HF were accurate in lateralizing the epileptogenic area in patients with TLE, concordant with the EEG in 92%; there was no false lateralization. In those patients who underwent surgery, there was a correlation between the degree of mesial temporal sclerosis demonstrated by histopathology, the amount of volume reduction, and the asymmetry. In patients with non-TLE, there was no volume asymmetry of AM or HF. The MR qualitative assessment yielded positive lateralization in patients with TLE in 56%, conflicting lateralization in 20%, and lateralization contralateral to the focus in 12%. A hyperintense signal in mesial structures was found ipsilateral to the focus in 40% and contralateral in 12% of patients with TLE. Volumetric study improves the diagnostic yield of MRI evaluation in patients with TLE not related to gross structural lesions. The interrater variability is low and the data are accurate and reproducible. Because they are quantitative, volumetric studies permit better comparison of results in different subgroups of patients with TLE.

Frequency of hepatitis C in acute post-transfusion hepatitis after open-heart surgery: a prospective study in 1,476 patients

Post-transfusion hepatitis was studied prospectively in 1,476 patients undergoing open-heart surgery between 1985 and 1988. Thirty-three (2.2%) patients suffered from post-transfusion hepatitis. Acute post-transfusion hepatitis was attributed to hepatitis B in one case and to hepatitis C in ten patients (0.7%). Four additional patients had preexisting serologic markers of hepatitis C. In 22 (1.5%) patients, hepatitis B or C was excluded as a cause of liver disease. Seroconversion for hepatitis C virus occurred from 3 weeks to more than 6 months after infection. Chronic hepatitis C developed in four patients. In addition, seroconversion to anti-HCV was observed in four patients with moderately elevated aminotransferases. In the control patients anti-HCV antibodies were found in 0.5%. The characteristics of acute hepatitis C after blood transfusion are shown and compared to 22 patients with acute hepatitis non-A, non-B, non-C. The etiology of these 22 cases is discussed.

A Monte Carlo method for conformational analysis of saccharides

A Metropolis Monte Carlo (MMC) algorithm was applied to explore conformational spaces spanned by the exocyclic dihedral angles of four disaccharides alpha-D-Man(1-->3)-alpha-D-Man(1-->O)Me (1), alpha-D-Man(1-->2)-alpha-D-Man(1-->O)Me (2), methyl beta-cellobioside (3), and methyl beta-maltoside (4). The simulation method uses the HSEA force field and randomly samples the conformational space with an automatic preference for low-energy states. In comparison to a systematic grid search, MMC offers a much more convenient and efficient protocol for the computation of ensemble average values of experimentally accessible NMR parameters such as NOE effects or 3J coupling constants. Energy barriers of a few kcal/mol were found to be surmounted easily when running the simulations with the temperature parameter set at room temperature, whereas passing significantly higher barriers required elevated temperature parameters. Ensemble average NOE values were calculated using the MMC technique and a conventional systematic grid search showing that the MMC method adequately samples the conformational spaces of 1-4. Theoretical NOEs derived for global or local minimum conformations are different from ensemble average values, and it is shown that averaged NOEs agree significantly better with experimental data. Ensemble average NOEs for 1 derived from MMC/HSEA, and previously reported MM2CARB and AMBER calculations all showed good agreement with experimental data, with MMC/HSEA giving the closest fit.

Cardiac effects of R 79595 and its isomers (R 80122 and R 80123) in an acute heart failure model. A new class of cardiotonic agents with highly selective phosphodiesterase III inhibitory properties

R 79595 (N-cyclohexyl-N-methyl-2-[[[phenyl (1,2,3,5-tetrahydro-2 oxoimidazo [2,1-b]-quinazolin-7-yl) methylene] amin] oxy] acetamide) and its isomers represent a novel class of compounds with phosphodiesterase (PDE) inhibitory and cardiotonic (positive inotropic) actions. The cardiac effects of this class of compounds were investigated in the hexobarbital-depressed heart-lung preparation of the guinea-pig. After induction of heart failure (reduction of cardiac output to 25% of the initial value) cumulative addition of R 79595 or its isomers R 80122 (E-isomer) and R 80123 (Z-isomer) concentration-dependently reversed the cardiac depressant effects of hexobarbitone-Na. With regard to reconstitution of contractility and cardiac function R 80122 (E-isomer) was 10 fold more potent than R 79595 (1:1 mixture of the isomers) and nearly 100 fold more potent than R 80123 (Z-isomer). Furthermore, the cardiotonic action of the most potent isomer (R 80122) was compared to the effects of several positive inotropic reference compounds. The order of cardiotonic potency was as follows: (-)-adrenaline > R 80122 = adibendan > digitoxin > milrinone = enoximone > theophylline. Adibendan (EC50 value: 6.7 +/- 1.8 x 10.-8 mol/l), which showed cardiotonic effects in the same concentration range as R 80122 (EC50 value: 6.1 +/- 1.3 x 10(-8) mol/l), was significantly (p < 0.01) less effective than R 80122 with respect to the maximally induceable increase in cardiac output (CO). The cardiotonic effects of R 80122 could be observed in the low concentration range of 3 x 10(-8) to 1 x 10(-6) mol/l, whereas enoximone (EC50 value: 1.2 +/- 0.1 x 10(-5) mol/l) and milrinone (EC50 value: 8.9 +/- 3.5 x 10(-6) mol/l) elicited positive inotropic effects at 100 fold higher concentrations. Digitoxin was 10 fold less and theophylline was 300 fold less potent than R 80122 with regard to reconstitution of heart function. The cardiotonic effects of R 80122 were not accompanied by an increase in heart rate as found with milrinone, theophylline or (-)-adrenaline in this model. Furthermore, the PDE inhibitory effect of R 79595 and its E-isomer R 80122 were investigated in partially purified isoenzymes from guinea-pig ventricles. The IC50 values of R 79595 and R 80122 on PDE I-IV were compared to the IC50 values of adibendan, milrinone, enoximone and theophylline. The selectivity of an inhibitor for PDE III was evaluated by division of its IC50 values on PDE I, II and IV by the IC50 value on PDE III. R 80122 was the most potent and selective PDE III inhibitor.(ABSTRACT TRUNCATED AT 400 WORDS)

Veratridine-induced intoxication: an in vitro model for the characterization of anti-ischemic compounds?

Due to the complexity of ischemia-induced cellular dysfunction many different pharmacological approaches have been tested to improve cellular ischemia resistance. However, despite the importance of [Na+]i for ischemia-induced dysfunction, only very few studies have investigated the contribution of the Na+ channel to ischemia-induced failure of intracellular ion homeostasis. Since an activation of Na+ channels by veratridine also results in a failure of intracellular ion homeostasis, the veratridine- and ischemia-induced alterations of cellular function were compared. Moreover, despite the difference in the electrophysiological changes induced by veratridine and ischemia, the possible involvement of a slowly inactivating, less selective Na+ channel in both veratridine- and ischemia-induced cellular dysfunction is discussed. As a conclusion it is suggested that veratridine intoxication could be a helpful in vitro method for the characterization of putative anti-ischemic compounds.

Anatomic basis of amygdaloid and hippocampal volume measurement by magnetic resonance imaging

Both the amygdala and the hippocampus are involved in the pathogenesis of a number of neurologic conditions, including temporal lobe epilepsy, postanoxic amnesia, and Alzheimer's disease. To enhance the investigation and management of patients with these disorders, we developed a protocol to measure the volumes of the amygdala and as much of the hippocampus as possible (approximately 90 to 95%) using high-resolution MRI. We present the anatomic basis of these two protocols and our results in normal control subjects. These volumetric studies of the amygdala may clarify the role of this structure in the pathogenesis of temporal lobe epilepsy.

Anatomy, histology, and pathology of coronary arteries: a review relevant to new interventional and imaging techniques--Part IV

In the last 15 years, intense interest has focused on various interventional pharmacologic and mechanical forms of therapy for the treatment of atherosclerosis coronary artery disease. Many techniques and devices (dilating balloons, perfusion catheters, thermal probes and balloons, lasers, atherectomy devices, stents, intravascular ultrasound) have been used or are under study for future use. Many of these techniques and devices require an understanding of histologic and pathologic features of the coronary arteries and diseases which affect them. This article reviews selective areas of anatomy, histology, and pathology relevant to the use of various new interventional techniques. Part IV of this review will focus on congenital coronary artery anomalies, myocardial bridges, coronary aneurysm, emboli, and dissection and clinical implications regarding echocardiographic imaging techniques.