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Biomedical subjects

R Kraft

Publications and source records attributed to R Kraft.

At least 109 records · Page 6Linked to original sources
PubMed1992

Carcinosarcoma of the urinary bladder: a distinct variant characterized by small cell undifferentiated carcinoma with neuroendocrine features.

The clinicopathological features of two carcinosarcomas of the urinary bladder are reported. The tumours occurred in a 64- and a 66-year-old patient presenting with haematuria and both were polypoid. The epithelial component was consistent with small cell undifferentiated carcinoma with neuroendocrine differentiation, whereas the sarcomatous component did not display specific features. The carcinomatous component showed immunohistochemical reactivity for different epithelial markers as well as for chromogranin and neuron specific enolase. Conversely, the sarcomatous cells stained strongly for vimentin and in one case for muscle actin and smooth muscle actin. The differential diagnosis of biphasic tumours of the bladder is discussed and the literature reviewed.

Actins↗
PubMed1992

Malignant cells are collected on circular staplers.

Anastomotic recurrence after resection of colorectal carcinoma has been attributed to insufficient clearance, migration of tumor cells into lymphatics, or implantation of exfoliated malignant cells during anastomosis. We studied 10 patients submitting to low anterior resection for cancer 6 to 16 cm (mean, 12.6 cm) from the anal verge. The anastomosis was performed with a circular stapler introduced transanally into the rectum using the established technique. No lavage of the rectal stump with a cytotoxic agent was conducted before the anastomosis was performed. Having completed the anastomosis, the stapler and the doughnuts were washed with saline, which was collected for cytologic examination. The doughnuts were then examined histologically; all were tumor free. In 9 of the 10 cases, malignant cells were identified in the centrifuged saline. It may be that malignant cells collected by the stapler are implanted during anastomosis and cause subsequent anastomotic recurrence.

Aged↗
PubMed1992

Limited proteolysis of streptokinase and properties of some fragments.

Limited proteolysis of streptokinase (Sk) by trypsin and thermolysin was performed under various incubation conditions and analysed by polyacrylamide gel electrophoresis. Several fragments (Sk1, Tr27, Tr17, Th26, and Th16) were isolated and characterized further. The N-terminal sequences of Tr27, Tr17, Th26, Th16 and the C-terminal sequences of Tr27 and Th26 were determined by partial sequencing. The evidence available allows the positioning of these fragments within the Sk sequence. Fragment Sk1 is obtained by carefully standardized tryptic digestion of Sk and gel chromatography under non-denaturing conditions. Sk1 is formed by a large polypeptide Ser60-Lys293 and non-covalently bonded smaller polypeptides composed of amino acids from the N-terminal region Ile1-Lys59 of Sk. Fragment Tr27 consists of the large polypeptide Ser60-Lys293 of Sk1, and can be obtained from Sk1 by removal of the smaller N-terminal polypeptides under denaturing conditions. Fragment Th26 is composed of amino acids Phe63-His291. The N-termini of fragments Tr17 and Th16 start with Glu148 and Ile151. From their electrophoretically-determined sizes it can be concluded that they most probably have the same C-terminal amino acids, Lys293 and His291, as fragments Tr27 and Th26, respectively. Secondary structure elements of similar composition were found in all the fragments studied using circular dichroism (c.d.) and infrared (i.r.) measurements. Differential scanning calorimetric (d.s.c.) measurements were performed in order to correlate the sequence regions of Sk to energetic folding units of the protein. Fragments Sk1, Tr27, Th26, Tr17, and Th16 show one melting peak in the temperature range from 42.8 to 46.1 degrees C (thermal unfolding stage). For fragment Sk1, this melting peak can be separated by deconvolution into two transitions at T1 = 46.1 degree C and T2 = 47.3 degrees C with delta H1 = 450 kJ/mol and delta H2 = 219 kJ/mol, respectively. Fragments Tr17 and Th16 show one two-state transition at T = 42.8 degrees C with delta H = 326 kJ/mol.

Amino Acid Sequence↗
PubMed1992

Sequence organization of variant mouse 4.5 S RNA genes and pseudogenes.

The rodent 4.5 S RNA is an RNA polymerase III product with a sequence related to the Alu family of interspersed repeated DNA. A previous study identified a tandem array of 4.2-kb repeating units that contain the 4.5 S RNA coding sequence as well as many short repetitive sequences. To understand the genomic organization of this gene family, we have isolated and characterized 4.5 S RNA sequences that are part of the tandem array as well as identified members that are not part of the array. One variant 4.5 S RNA gene family member exhibits length polymorphisms in its minisatellite sites relative to the single previously reported gene. The 4.5 S RNA sequences that are not part of the tandem array possess many of the features of processed pseudogenes and are found adjacent to other interspersed repeated elements. These findings suggest that the mouse 4.5 S RNA can behave as a retroposon, resulting in the accumulation of 4.5 S RNA-like elements at many sites in the genome.

Animals↗
PubMed1992

Steroid-1-dehydrogenase of Rhodococcus erythropolis: purification and N-terminal amino acid sequence.

The inducible steroid-1-dehydrogenase from the bacterium Rhodococcus erythropolis IMET 7030 was purified to homogeneity using affinity chromatographic, electrophoretic, and ion exchange techniques. The spectrum of the pure enzyme is characterized by the associated FAD. The M(r) of the enzyme is 56,000. The amino acid composition and the sequence of the 13 N-terminal amino acids are given.

Amino Acid Sequence↗
PubMed1992

Novel, contrast gradient-oriented, automated chromatin texture analysis. I. Feasibility study on nuclei from benign and malignant breast epithelial cell lines in fine needle aspirates.

Coarse granularity of nuclear chromatin texture is a prominent feature of most malignant cell lines. We have chosen the abrupt transition from eu- to heterochromatic foci (high contrast gradient [CG]) as a novel parameter for coarseness. This feature was quantified using automated image analysis of single nuclei in smears stained by the May-Grünwald-Giemsa technique. The principle of this approach consists of eliminating, with the help of subtraction between two image lowpass filters, the small grey level differences among pixels, so that only high CG values are retained on the digitized image. The sum of these distinctive microareas is then taken as a fraction of the area of the peripherally eroded nucleus, and this ratio is designated as contrast gradient index (CGI) per nucleus. This method was tested on fine needle aspirates from 11 patients with benign breast disease (BBD) and 14 with mammary carcinoma (CA). For each specimen, 60 nuclei were analyzed, with a measuring time per nucleus of about 1 min. A high significant distinction between epithelial cell populations in BBD and CA, respectively, was obtained by variance analysis of all CGIs per nucleus (p = 2 x 10(-18). The median and the mean values of CGI per specimen were the next best discriminators, followed by the modes and the standard deviation of CGI per specimen. The percentage of nuclei per specimen with CGI values of greater than 12 was also significantly greater in CA than in BBD.

Adolescent↗
PubMed1991

Amino acid sequence analysis of the beta- and gamma-subunits of eukaryotic initiation factor eIF-2. Identification of regions interacting with GTP.

By affinity labelling using two different GTP photoaffinity analogues we previously demonstrated that both the beta- and gamma-subunits of eukaryotic initiation factor eIF-2 are involved in GTP binding (Bommer, U.-A. and Kurzchalia, T.V. (1989) FEBS Lett. 244, 323-327). We have now applied the same method in combination with CNBr cleavage and microsequence analysis in order investigate which part of the polypeptide chain of eIF-2 beta is in close contact to the bound GTP. From the three main CNBr fragments of eIF-2 beta, the C-terminal one was found to be labelled by the applied GTP photoaffinity analogue, Guo(2',3'-TDBH)ppp. Because the cDNA sequence of the gamma-subunit of eIF-2 has not yet been published and because cDNA sequence analysis of eIF-2 beta revealed only two out of three consensus sequence elements of a GTP-binding domain, we also sequenced the CNBr fragments of eIF-2 gamma. In this way, sequences containing about 50 amino acid residues were obtained. Taken together with the recently published N-terminal sequences of tryptic peptides of eIF-2 gamma from pig liver (Suzuki et al. 1990, J. Biochem. 108, 635-641), about 30% of the total sequence is now known. One of the CNBr fragments from rabbit eIF-2 gamma contains a sequence (AXXAXXGK) which in several respects resembles that of the consensus sequence element absent from the beta-subunit.

Affinity Labels↗
PubMed1991

Determination of bencyclane in human plasma by means of capillary gas chromatography and nitrogen-phosphorus selective detection.

A sensitive and specific method for the determination of bencyclane in human plasma is presented. Bencyclane was extracted from human plasma with two 3-ml volumes of isooctane and was shaken for 10 min. The organic phase was separated and evaporated to dryness at 40 degrees C under a nitrogen stream. The residue was dissolved and an aliquot was injected into the gas chromatograph. The separation was performed with a DB-17 column with helium as the carrier gas. Nitrogen-selective detection was performed. The quantification was performed with the signal output. The limit of detection was 1 ng/ml.

Bencyclane↗
PubMed1991

Diffuse centrocytic and/or centroblastic malignant non-Hodgkin's lymphomas: comparison of mitotic and pyknotic (apoptotic) indices.

Mitotic indices (MIs) and pyknotic (apoptotic) indices (PIs) were assessed in diffuse centrocytic (CC, n = 10), centroblastic/centrocytic (CB/CC, n = 18) and centroblastic (CB, n = 20) malignant non-Hodgkin's lymphomas (NHL). Significant differences were observed. MIs were lowest in CC (median: 0.07%), intermediate in CB/CC (0.18%) and highest in CB (0.43%) NHLs. The PIs exhibited a similar pattern. The PIs of CC (0.11%) and CB/CC (0.17%) NHLs were significantly different from those of CB lymphoma (0.62%). The ratios MI/PI per case, as well as MIs and PIs per case, varied greatly and showed considerable overlapping, thus documenting a marked inter-case and inter-group heterogeneity. MIs tended to loosely correlate with PIs in a non-linear fashion, which raises the question of feedback mechanisms. More information is needed on mitotic time (TM) and apoptotic time (TA), in order to estimate cell doubling time from data on MIs and PIs.

Adult↗
PubMed1990

Enlargement of regional lymph nodes in renal cell carcinoma is often not due to metastases.

Preoperative axial computerized tomography scans in 163 patients with renal cell carcinoma were reviewed to assess the predictive value for the diagnosis of regional lymph node metastases. Computerized tomography was falsely negative in 5 patients: 2 had metastatic lymph nodes in the renal hilus adjacent to the primary tumor measuring 2 and 2.5 cm., and 3 had micrometastases in nodes of less than 1 cm. In 43 patients enlarged lymph nodes with a diameter of 1 to 2.2 cm. (median 1.4 cm.) were diagnosed on the preoperative scan and this was confirmed at nephrectomy and pathologically. In 18 of these 43 patients (42%) histological study showed metastases of the renal cell carcinoma in the enlarged lymph nodes. In the other 25 patients (58%) the enlarged nodes showed only inflammatory changes and/or follicular hyperplasia. This finding was significantly more frequent in patients with tumor involvement of the renal vein and tumor necrosis (p = 0.0044). We conclude that the sensitivity of preoperative computerized tomography is good for the detection of enlarged lymph nodes in patients with renal cell cancer (95%). However, significant lymph node enlargement frequently may be caused by inflammatory changes, especially in the presence of tumor necrosis. This radiological finding should not be misinterpreted as metastatic disease, unless it has been proved cytologically by fine needle aspiration.

Carcinoma, Renal Cell↗
PubMed1990

The signal sequence receptor has a second subunit and is part of a translocation complex in the endoplasmic reticulum as probed by bifunctional reagents.

Bifunctional cross-linking reagents were used to probe the protein environment in the ER membrane of the signal sequence receptor (SSR), a 24-kD integral membrane glycoprotein (Wiedmann, M., T. V. Kurzchalia, E. Hartmann, and T. A. Rapoport. 1987. Nature [Lond.]. 328:830-833). The proximity of several polypeptides was demonstrated. A 22-kD glycoprotein was identified tightly bound to the 34-kD SSR even after membrane solubilization. The 34-kD polypeptide, now termed alpha SSR, and the 22-kD polypeptide, the beta SSR, represent a heterodimer. We report on the sequence of the beta SSR, its membrane topology, and on the mechanism of its integration into the membrane. Cross-linking also produced dimers of the alpha-subunit of the SSR indicating that oligomers of the SSR exist in the ER membrane. Various bifunctional cross-linking reagents were used to study the relation to ER membrane proteins of nascent chains of preprolactin and beta-lactamase at different stages of their translocation through the membrane. The predominant cross-linked products obtained in high yields contained the alpha SSR, indicating in conjunction with previous results that it is a major membrane protein in the neighborhood of translocating nascent chains of secretory proteins. The results support the existence of a translocon, a translocation complex involving the SSR, which constitutes the specific site of protein translocation across the ER membrane.

Amino Acid Sequence↗
PubMed1990

Hodgkin's disease and CD30-positive anaplastic large cell lymphomas--a continuous spectrum of malignant disorders. A quantitative morphometric and immunohistologic study.

The authors have examined cellular areas of lymphoma tissue in 28 cases of Hodgkin's disease (HD) or anaplastic large cell lymphoma (ALCL, 'Ki-1 cell lymphoma') to evaluate the boundaries between the two entities. Methods applied included conventional histology; test point analysis; semiautomated morphometry of nuclear profile features of Reed-Sternberg and other atypical large cells (RSALCs); and immunohistochemistry of these elements on all paraffin sections and, in 15 cases, on frozen sections. Mean nuclear profile morphotypes of RSALCs per case varied independently of immunophenotype and histologic diagnosis. Conversely, immunohistochemistry demonstrated significant, although not consistent, preferential positivities of these CD30+ elements for CD15 in HD, and for epithelial membrane antigen (EMA) and CD43 in ALCLs. In the latter, RSALCs also exhibited a tendency for CD45 and CD45RO positivity and for the expression of T-cell-associated antigens. However, there were considerable overlaps. This continuous spectrum of RSALC nuclear profile morphotypes and immunophenotypes, ranging from HD over questionable cases, intermediate between HD and ALCL, to ALCLs, was paralleled by differences in the reactive component of lymphomas. Lymphocytes and granulocytes were significantly deficient in ALCLs.

Adolescent↗
PubMed1989

Full-length rat alpha and beta cardiac myosin heavy chain sequences. Comparisons suggest a molecular basis for functional differences.

The two cardiac myosin heavy chain isoforms, alpha and beta, differ functionally, alpha Myosin exhibits higher actin-activated ATPase than does beta myosin, and hearts expressing alpha myosin exhibit increased contractility relative to hearts expressing beta myosin. To understand the molecular basis for this functional difference, we determined the complete nucleotide sequence of full-length rat alpha and beta myosin heavy chain cDNAs. This study represents the first opportunity to compare full-length fast ATPase and slow ATPase muscle myosin sequences. The alpha and beta myosin heavy chain amino acid sequences are more related to each other than to other sarcomeric myosin heavy chain sequences. Of the 1938 amino acid residues in alpha and beta myosin heavy chain, 131 are non-identical with 37 non-conservative changes. Two-thirds of these non-identical residues are clustered, and several of these clusters map to regions that have been implicated as functionally important. Some of the regions identified by the clusters of non-identical amino acid residues may affect actin binding, ATP hydrolysis and force production.

Amino Acid Sequence↗
PubMed1989

[Differential diagnosis of atypical plasma cells in the cerebrospinal fluid].

2102 samples of lumbar cerebrospinal fluid (CSF) were examined by qualitative cytology for atypical plasma cells. Samples from seven patients contained such cells. Retrospective investigation of these patients revealed that four of them had had neuroborreliosis, one had multiple sclerosis, one herpes zoster and one malignant non-Hodgkin lymphoma. It is concluded that in a case of unexplained meningoradiculitis with lymphoplasmocytic reaction in the CSF, morphological analysis of the plasma cells can provide important diagnostic pointers.

Adult↗