Cyanide poisoning victims as corneal transplant donors.
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Biomedical subjects
Publications and source records attributed to K Weber.
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Previous models of p36 based on proteolytic fragments describe the tail and core as two noninteracting domains. However, the monoclonal antibody H28 recognizes a discontinuous epitope, which covers the peptide segments around Ser 25 in the tail and around Glu 65 in the core of porcine p36. Thus, the phosphorylatable Tyr 23 is much closer to the first consensus sequence (residues 46-62) of Ca2+/lipid-binding proteins than previously thought. This apposition is in line with biochemical experiments indicating an influence of core ligands on tyrosine phosphorylation and an enhanced Ca2+ requirement of the modified p36 in phospholipid binding.
Erythema migrans or Lyme borreliosis may be classified according to 3 stages. Erythema migrans is the typical initial lesion of the disease, often associated with general symptoms. Carditis, meningitis, musculoskeletal symptoms including arthralgia may develop in stage 2; arthritis (arthralgia), acrodermatitis chronica atrophicans (ACA), and encephalomyelitis may occur in stage 3. Borrelial lymphocytoma may be seen either in the early phase of the disease or along with the ACA. However, there is no definite therapeutical concept, so far. We recommend tetracyclines during the first stage, and high doses of penicillin G during stages 2 and 3 as well as for pregnant women.
The in vitro phosphorylation of chicken desmin by the catalytic subunit of cAMP-dependent protein kinase was analysed. Phosphorylated desmin loses the ability to form intermediate filaments (IFs). Fragmentation at the sole cysteine and mild chymotryptic treatment show a differential phosphorylation of the three structural domains. Only the amino-terminal head domain is the target of the kinase. Peptide analysis shows that serine 29 is fully phosphorylated, while serine 35 and 50 are phosphorylated at least at 22 and 50% respectively. All three sites show the sequence arginine-X-serine with X being a small residue. These results strengthen the view that the nonhelical head domain has a strong influence on filament integrity most likely via a direct influence of some of its arginine residues. Taken together with previous results (Inagaki et al., 1987) on the phosphorylation of vimentin by kinase A, a new view on IFs emerges. Phosphorylation could allow for regulatory processes in assembly and turnover.
Protein I is a hetero-tetramer which contains two copies each of p11 and p36. p36 (calpactin I, lipocortin II) is a major substrate of retrovirally encoded tyrosine protein kinases, while p11 modulates several Ca2+-induced properties also displayed by p36 alone. Here we have characterized the p11 binding site on p36 by fluorescence spectroscopy using porcine p36 labelled at cysteine 8 with the fluorophore Prodan (6-proprionyl-2-dimethylamino-naphthalene). We have used peptides of differing length from the amino-terminal domain of p36 to restrict the major binding site to the first 12 residues. Noticeable binding is still observed with a peptide containing only the first nine residues. Interestingly the N-terminal acetyl group of p36 forms a functional part of the p11 binding site. CD studies indicate that the binding region can form an alpha-helix, which seems to have amphiphatic properties when projected on a helical wheel. This structural element is also known for a calmodulin binding protein. Thus the question is raised whether other p11/calmodulin-related proteins interact with their target proteins via a similar mechanism. We also discuss how p11 could modulate p36 associated properties.
Intermediate filaments (IF) isolated from the oesophagus epithelium of the snail Helix pomatia contain two polypeptides of mol. wt 66,000 (A) and 52,000 (B), which we have now characterized by in vitro self-assembly studies and by protein sequences. A and B can each form morphologically normal IF and share extended regions of sequence identity. All A-specific sequences seem to locate to an extension of the carboxyl-terminal domain. Although the Helix protein(s) reveal the IF-consensus sequences at the ends of the coiled-coil, the remainder of the rod domain shows conservation of sequence principles rather than extended homology, when compared with any subtype of vertebrate IF proteins. Interestingly, the Helix proteins have the longer coil 1b domain found in nuclear lamins and not in cytoplasmic IF proteins of vertebrates. They lack, however, the karyophilic signal sequence typical for lamins. Obvious implications for IF evolution and structure are discussed.
Gastric carcinomas have been assayed for the presence of villin and for the small intestinal hydrolases aminopeptidase N and sucrase isomaltase. These proteins seem not to be present in normal stomach epithelium. However intestinal metaplasia in stomach, and tumour cells in the glandular patterns of gastric carcinoma were positive for all three markers, showing characteristic apical positivity. In contrast, in diffuse gastric carcinomas the percentage of signet ring cells positive for these markers varied from 10-100% with each marker showing a similar percentage of positive cells. Testing of gastric carcinomas with antibodies specific for different keratin polypeptides showed that while all 7 tumours were positive for keratins 8 and 18.2 were also positive for keratin 7. In the keratin 7 positive tumours all tumour cells were keratin 7 positive. The keratin 8 antibody also reacted on routinely fixed specimens. Thus gastric carcinomas reveal different degrees of gastric and intestinal differentiation.
Mongolian gerbils were exposed to 15 min of cerebral ischemia. Quantitative histology was used to establish neuronal damage in the CA1, CA2/3, and CA3 sectors of the hippocampus 2 weeks after the insult. Seven moribund animals were sacrificed earlier to examine whether there is a correlation between hippocampal damage and mortality. Surviving animals had a 86.6% loss of CA1 neurons. In the CA2/3 and CA3 sectors 62.7 and 72.6% of the neurons were preserved. Moribund animals had a further dramatic loss of nerve cells in these sectors, to 14.8 and 20.3%, respectively. The reduction of CA2/3 neurons and survival time were correlated. In addition, gerbils which would later become moribund were found to have a significant increase in plasma osmolarity from 319 to 342 mosm/liter and of hematocrit from 47.4 to 53.9 at day 4 after ischemia.
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p36, a major cytoplasmic substrate of pp60 src kinase, is present beneath the plasma membrane. It can be isolated either as a monomer or as a heterotetramer (protein I) containing two copies each of p36 and a unique p11 polypeptide. To compare the expression rules of p36 and p11 as well as their cellular distributions, monoclonal antibodies to the two porcine proteins were isolated. In tissue culture cells p11-specific antibodies decorated the same submembranous compartment previously seen with antibodies to p36 and fodrin or spectrin and followed the p36 images under all fixation/extraction conditions tested. Immunofluorescence microscopy on tissue sections showed coincident expression patterns of both proteins confirming and extending previous results with p36 antibodies. Antibodies with limited cross-species reaction have been used to trace the fate of porcine p11 and p36 injected into cultured cells. Both proteins are incorporated in the submembranous compartment, where they remain in Triton cytoskeletons prepared in the presence but not in the absence of Ca2+. The incorporation of p36 in vivo conforms with its Ca2+-dependent binding to actin, fodrin, and certain phospholipids in vitro. In contrast, the incorporation of p11 seems to depend on an in situ interaction with p36 or an exchange with endogenous p11 present on p36. The combined results indicate a strong coupling of p11 and p36 in cellular compartmentalization and tissue differentiation.
Iodine-123 (I-123) meta-iodobenzylguanidine (MIBG) imaging was performed in 31 patients. Three patients were without cardiac disease and 28 had idiopathic dilated cardiomyopathy with various degrees of left ventricular dysfunction. The qualitatively assessed myocardial I-123 MIBG scintigrams and the myocardial versus mediastinal I-123 MIBG uptake ratio were related to I-123 MIBG activity and norepinephrine concentration determined from endomyocardial biopsy samples taken from the right side of the interventricular septum. Scintigrams and the MIBG uptake ratio were also related to plasma catecholamine concentrations, left ventricular ejection fraction and New York Heart Association functional class. Patients with distinct myocardial I-123 MIBG uptake (score 1) had a normal ejection fraction (58 +/- 16%). Patients with diffusely reduced uptake or scintigraphic defects (score 2) had a significantly lower ejection fraction (38 +/- 9%, p less than 0.05), whereas patients with shadowy or no visible myocardial uptake (score 3) had the lowest ejection fraction (23 +/- 6%, p less than 0.002 versus patients with score 2). The scintigraphically determined I-123 MIBG activity in the septal region correlated significantly with I-123 MIBG activity from the endomyocardial biopsy samples (r = 0.78, p less than 0.001, n = 9). The myocardial versus mediastinal I-123 MIBG activity ratio was significantly related to myocardial norepinephrine concentration (r = 0.63, n = 28) and to left ventricular ejection fraction (r = 0.74, n = 31). These data suggest that myocardial I-123 MIBG scintigraphy is a useful noninvasive method for the assessment of myocardial adrenergic nervous system disintegrity in patients with idiopathic dilated cardiomyopathy.
Automotive restraint systems suitable for use with low birth weight infants were crash tested using a small infant dummy developed for the study. Conventional semiupright rear-facing child restraints were tested, as well as a new car bed restraint that may be advantageous for infants who are medically fragile and who must remain in a prone or supine position. This car bed can be adapted to accommodate a very small infant effectively.
mAbs specific for titin or nebulin were characterized by immunoblotting and fluorescence microscopy. Immunoelectron microscopy on relaxed chicken breast muscle revealed unique transverse striping patterns. Each of the 10 distinct titin antibodies provided a pair of delicate decoration lines per sarcomere. The position of these pairs was centrally symmetric to the M line and was antibody dependent. The results provided a linear epitope map, which starts at the Z line (antibody T20), covers five distinct positions along the I band (T21, T12, T4, T1, T11), the A-I junction (T3), and three distinct positions within the A band (T10, T22, T23). The epitope of T23 locates 0.2 micron before the M line. In immunoblots, the two antibodies decorating at or just before the Z line (T20, T21) specifically recognized the insoluble titin TI component but did not recognize TII, a proteolytic derivative. All other titin antibodies recognized TI and TII. Thus titin molecules appear as polar structures lacking over large regions repetitive epitopes. One physical end seems related to Z line anchorage, while the other may bind close to the M line. Titin epitopes influenced by the contractional state of the sarcomere locate between the N1 line and the A-I junction (T4, T1, T11). We discuss the results in relation to titin molecules having half-sarcomere lengths. The three nebulin antibodies so far characterized again give rise to distinct pairs of stripes. These locate close to the N2 line.
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In a study on 121 consecutive patients with erythema migrans, 65 patients obtained oral penicillin, 36 tetracyclines, and 20 amoxicillin-clavulanic-acid. Follow-up was carried out for a median of 29, 17, and 7 months, respectively. In another limited trial on 29 patients with acrodermatitis chronica atrophicans (ACA), 14 patients received oral penicillin, 9 parenteral penicillin, and 6 tetracyclines. There was no statistically significant difference among treatment groups in both therapeutic trials, with the exception of different follow-ups due to the nonrandomized study design and different occurrence of the Jarisch-Herxheimer reaction in patients with erythema migrans. Later extracutaneous manifestations developed in 27% of the patients with erythema migrans and in 47% of the patients with ACA despite antibiotic therapy. We could not prove the superiority of any antibiotic tested in either early or late European Lyme borreliosis.
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Hepatobiliary sequential scintigraphies by 99m Tc-ROTOP-EHIDA were carried out for judging the dual liver system after experimental auxiliary transplantation of a part of the liver. A functional advantage of the host liver in contrast to the transplant was found in all cases investigated. Ischemic transplant damages could be detected in all experiments and were scintigraphically recognised at an early stage. In addition to transplants with a functioning entire parenchyma, the investigations showed transplants with functionally active parenchyma zones and such ones without any functional evidence. A quantifiable determination of the global functional capacity of the hepatobiliary system of both livers was possible and also the evidence on residual functions. The different behaviour of the kinetics of the radio-pharmacon with normal function and in case of hepatic ischemia is discussed.
The body muscle cells of the nematode Ascaris lumbricoides are characterized by massive amounts of intermediate filaments (IF). These occur in all three regions of this giant cell type. They traverse the cytoplasm of the balloon-like belly, which houses the nucleus, and occur as bundles in the arm-like extensions to the nerve. The organization of IF in the third region, the contractile fiber, was analyzed further by serial sections and three-dimensional reconstruction. IF bundles traverse the glycogen-rich lumina of the fiber and reach as baskets around the sarcomeres. Together with numerous dense bodies they form the Z-band-like arrangements. IF bundles reach the plasma membrane at hemidesmosome-like specializations often situated at deep membrane invaginations filled with a fibrillar component of the extracellular matrix. The ultrastructural appearance of IF bundles is connected to the contractional state of the sarcomeres. They appear straight in extended muscle but coil up upon contraction. In the pharynx massive IF bundles are oriented longitudinally. A second type of IF bundles follows the radially oriented sarcomeres. These reveal pronounced Z-band type structures with massive disks. IF surround the sarcomeres and seem to terminate at these disks. We discuss possible functions of the complex IF organization in body muscle and pharynx.