Biomedical subjects
Publications and source records attributed to B Behrens.
Brain metastases from prostate adenocarcinoma are rare; spread to brain as the only site of metastasis is even rarer. We present a patient with a large, cystic, solitary intracerebral metastasis from prostate adenocarcinoma. The pertinent literature is reviewed.
We identified lbpB, encoding the lipoprotein component of the meningococcal lactoferrin receptor. An LbpB mutant was unable to acquire Fe from lactoferrin and exhibits decreased surface binding to lactoferrin. Primer extension and reverse transcription-PCR analysis indicate that lbpB and lbpA are cotranscribed on a polycistronic Fe-repressible mRNA.
A large portion of the sequences of type II DNA-(cytosine-C5)-methyltransferases (C5-MTases) represent highly conserved blocks of amino acids. General steps in the methylation reaction performed by C5-MTases have been found to be mediated by some of these domains. C5-MTases carry, in addition at the same relative location, a region variable in size and amino acid composition, part of which is associated with the capacity of each C5-MTase to recognize its characteristic target. Individual target-recognizing domains (TRDs) for the targets CCGG (M), CC(A/T)GG (E), GGCC (H), GCNGC (F) and G(G/A/T)GC(C/A/T)C (B) could be identified in the C-terminal part of the variable region of multispecific C5-MTases. With experiments reported here, we have established the organization of the variable regions of the multispecific MTases M.SPRI, M.phi3TI, M.H2I and M.rho 11SI at the resolution of individual amino acids. These regions comprise 204, 175, 268 and 268 amino acids, respectively. All variable regions are bipartite. They contain at their N-terminal side a very similar sequence of 71 amino acids. The integrity of this sequence must be assured to provide enzyme activity. Bracketed by 6-10 'linker' amino acids, they have, depending on the enzyme studied, towards their C-terminal end ensembles of individual TRDs of 38 (M), 39 (E), 40 (H), 44 (F) and 54 (B) amino acids. TRDs of different enzymes with equal specificity have the same size. TRDs do not overlap but are either separated by linker amino acids or abut each other.
Endogenous digitalis-like factor (EDLF), an inhibitor of membrane Na+/K(+)-ATPase, is discussed to be involved in the pathogenesis of cirrhogenic portal hypertension, ascites formation and development of functional hepatorenal failure. Therefore, we investigated the serum content of this mediator in patients with liver cirrhosis Child-Pugh stage A, B, and C (n = 27) by means of enzyme immunoassay with a specific digoxin antibody. Furthermore, a correlation analysis was performed in order to find out correlations between signs of cell injury, cholestasis, synthetic cell function, ascites formation, and hepatorenal failure. Our results demonstrate that EDLF is significantly elevated in Child C cirrhosis (0.61 +/- 0.15 ng/ml) in comparison to Child A cirrhosis (0.013 +/- 0.2 ng/ml) and is also higher than in Child B cirrhosis (0.23 +/- 0.25 ng/ml). In patients without ascites EDLF (0.056 +/- 0.19 ng/ml) differs significantly from that of patients with non-complicated ascites (0.156 +/- 0.176 ng/ml) and from that of patients with therapy refractory ascites (0.66 +/- 0.17 ng/ml) or hepatorenal failure (1.56 ng/ml). There are no correlations between EDLF and renal function. Significant correlations were demonstrated for cholestasis (serum bilirubin), synthesis function (serum protein, Quick's value, cholinesterase, fibrinogen, albumin), and the degree of portasystemic encephalopathy (number connection test). We conclude that EDLF may act as a mediator in the process of progressive portal hypertension and its complications due to cirrhosis. This process of progression is caused by the inhibition of Na+/K(+)-ATPase, vasoconstriction, and endothelin secretion.
The use of intravenous melphalan at higher doses is limited by severe myelosuppression. It was postulated that GM-CSF would permit the use of higher dose melphalan with only moderate myelosuppression easily manageable in an outpatient setting. Therefore, a phase I study of intravenous melphalan utilizing GM-CSF (recombinant granulocyte-macrophage colony-stimulating factor) support was initiated. Intravenous melphalan at doses of 15-45 mg/m2 was administered every 28 days. GM-CSF was utilized at doses of 10-20 micrograms/kg/day subcutaneously Days 2-21 on a 28-day cycle. Twenty-five patients received 53 courses of therapy. The dose-limiting toxicities were severe or life-threatening granulocytopenia and thrombocytopenia. Utilizing 20 micrograms/kg/day GM-CSF, the maximum tolerated dose (MTD) of melphalan is 30 mg/m2 and, with 10 mg/kg/day GM-CSF, the maximum tolerated melphalan dose is only 20 mg/m2. One patient with ovarian cancer achieved a partial response. Because the reported MTD of intravenous melphalan without GM-CSF is 30 mg/m2, GM-CSF has not allowed sufficient escalation of the intravenous melphalan dose for routine outpatient use.
Interferon-beta-serine (IFN-beta-ser) is a muteine, recombinant IFN that is tolerated at a dose fivefold to 10-fold higher than IFN-alfa and interacts with the same cell membrane receptor as IFN-alfa. We hypothesized that at high doses IFN-beta-ser might induce a higher response rate than IFN-alfa in metastatic renal cell carcinoma. We undertook a phase II trial of IFN-beta-ser in patients with metastatic renal cell carcinoma. Patients were treated three times each week by a 2-hour intravenous infusion. Doses were escalated weekly (.25 to 5.5 mg, 1 mg = 180,000,000 U) until the maximum-tolerated treatment dose (MTTD) was determined. The MTTD is defined as one dose level less than that which caused grade 3 toxicity and was subsequently administered three times weekly for at least 4 weeks. Twenty-nine patients were entered, and 25 were assessable for response and toxicity. The performance status was 0-1 in all patients and only one patient received previous chemotherapy. The MTTD dose was 2.5 mg (range, 0.5 to 5.5 mg per treatment), although in 10 patients, doses were later deescalated because of cumulative toxicity. Initial dose-limiting toxicity and cumulative toxicity were fatigue, malaise, and fever in most patients. Hepatic transaminitis, neutropenia, and elevation of serum creatinine were also observed but were not dose-limiting. There was one complete response (CR) and four partial responses (PRs). All responses but one occurred in pulmonary metastases. The median time to response was 26 days (range, 17 to 102 days). These data demonstrate that IFN-beta-ser given in high doses exhibits significant antitumor activity in renal cell carcinoma; however, the objective response rate is 20%. This is no higher than previous IFN studies; therefore, we reject the hypothesis than IFN-beta-ser at high doses may induce a greater response rate than IFN-alfa. However, we did observe more responses than were seen in a similar trial undertaken with lower dose IFN-beta serine in renal cell carcinoma.
Until now, right atrial (RA) volume calculation by means of two-dimensional echocardiography (2-DE) has only been attempted in a single plane: the apical four-chamber view. Our study reports a new method for RA volume calculation using two intersecting 2-DE views. For this purpose, silicone rubber casts of 19 human necropsy hearts were obtained and thin-walled natural rubber moulds of the RA casts were prepared. Totally filled with and immersed in water, the moulds could be visualized in the apical four-chamber view and an additional 2-DE plane, the latter corresponding to the subcostal view in vivo. In this view the vertical extension of RA could be estimated. Areas and lengths of RA were determined in the respective planes, and RA volume was calculated by applying the formula, area x length, to two intersecting planes. Finally, volume of the silicone casts was determined angiocardiographically (Angio) using a biplane method (30 degrees RAO, 40 degrees LAO-40 degrees hepatoclavicular). The true RA volume was 106 +/- 23 ml (mean +/- 1 SD) as determined by water displacement. Using Angio an excellent correlation was found: the calculated volume amounted to 106 +/- 23 ml; the difference was 5.5 +/- 4.8 ml (n.s.); Angio vol = 0.93 true vol + 7.77; r = 0.95; SEE = 7.4 ml. Volume determination from the apical four-chamber view of 2-DE using a monoplane disk method resulted in a mean volume of 62 +/- 17 ml. The mean difference to the true RA volume was 44 +/- 16 ml (p less than 0.001). When volume calculations were made using the biplane method, a value of 105 +/- 22 ml resulted. The mean difference to true volumes was 7.4 +/- 4.8 ml: y = 0.84x + 15.88; r = 0.91; SEE = 9.4 ml. In an in vivo study endsystolic RA volumes were calculated in a normal adult population (n = 40) from the same intersecting planes as in vitro. A normal value of 38 +/- 6 ml/m2 was found. In vivo validation using Angio showed a slightly higher normal value of 43 = 7 ml/m2. Thus, 2-DE is highly accurate in determining RA volume. In the in vitro as well as in the in vivo study the results of monoplane calculations are clearly inferior to a method which also takes account of the vertical extension of RA.
Explore the source record for details and available documents.
In the multispecific DNA(cytosine-5)-methyltransferases (Mtases) of Bacillus subtilis phages SPR and phi 3T the domains responsible for recognition of DNA methylation targets CCA/TGG, CCGG, GGCC (SPR) and GCNGC, GGCC (phi 3T) represent contiguous sequences of approximately 50 amino acids each. These domains are tandemly arranged and do not overlap. They are part of a 'variable' segment within the enzymes which is flanked by 'conserved' amino acids, which are very similar amongst bacterial monospecific and the multispecific Mtases studied here. These results follow from a mutational analysis of the SPR and phi 3T Mtase genes. They further support our concept of a modular enzyme organization, according to which variability of type II Mtases with respect to target recognition is achieved by a combination of the same enzyme core with a variety of target-recognizing domains.
B. subtilis phage rho 11s codes for a multispecific DNA methyltransferase (Mtase) which methylates cytosine within the sequences GGCC and GAGCTC. The Mtase gene of rho 11s was isolated and sequenced. It has 1509 bp, corresponding to 503 amino acids (aa). The enzyme's Mr of 57.2 kd predicted from the nucleotide sequence was verified by direct Mr determinations of the Mtase. A comparison of the aa sequence of the rho 11s Mtase with those of related phages SPR and phi 3%, which differ in their methylation potential, revealed generalities in the building plan of such enzymes. At least 70% of the aa of each enzyme are contained in two regions of 243 and 109 aa at the N and C termini respectively, which are highly conserved among the three enzymes. In each enzyme, variable sequences separate the conserved regions. Variability is generated through the single or multiple use of related and unrelated sequence motifs. We propose that the recognition of those DNA target sequences, which are unique for each of the three enzymes, is determined by these variable regions. Evolutionary relationships between the three enzymes are discussed.
The phi 3T DNA methyltransferase (Mtase) and most of the SP beta Mtase genes have been sequenced. With the exception of their promoters, no difference was found between the phi 3T and SP beta Mtase genes which code for an enzyme with a Mr of 50 507, consisting of 443 amino acids (aa). Comparison of the deduced aa sequence of the phi 3T/SP beta type Mtase (target specificity: GGCC and GCNGC) with that of the previously established sequence of the SPR Mtase (Buhk et al., 1984) which has the target specificity GGCC and CCGG, reveals strong similarities between these two types of enzymes. There is, however, one striking difference: both the phi 3T/SP beta and the SPR enzymes contain at different positions inserts of 33 aa, which have no homology to each other. We suggest that the methylation specificity unique to each of the two types of Mtases (GCNGC in phi 3T/SP beta; CCGG in SPR) depends on these inserts, while the GGCC-specific modification potential common to all Mtases is determined by structures conserved in both types of enzymes. A DNA fragment of non-modifying phage Z, which shows homology to both flanks of the SPR Mtase gene, was also sequenced. This segment can be described as a derivative of SPR DNA, in which the Mtase gene and sequences at its 5' end have been deleted, with the deletion extending between two direct repeats of 25 bp.
Expression of the SPR methyltransferase gene from B. subtilis phage SPR cloned into lambda and SPP1 was studied by analyzing the sensitivity of the hybrid phage DNAs to restriction by the enzymes HaeIII, MspI, and HpaII. The following results were obtained: (1) The genes were expressed both in the homologous (B. subtilis) and heterologous (E. coli) host. (2) The specificity of the expression of the cloned gene was identical to that of the gene in SPR. (3) Expression depended on the orientation of the cloned segment within the vector DNAs suggesting that vector promoters were involved in transcription. The coding strand of the cloned DNA was identified through hybridization with SPR mRNA.
A collaborative study was conducted using a modified AOAC method (sugars in chocolate) for the determination of fructose, glucose, sucrose, and maltose in presweetened cereals by high pressure liquid chromatography (HPLC). Eight samples consisting of 6 products were analyzed in duplicate by the HPLC method and the AOAC Lane-Eynon method. The AOAC method was modified to use water-alcohol (1 + 1) and Sep-Pak C18 cartridges for sample cleanup. The HPLC results indicate precision comparable to the lane-Eynon method and the chocolate method. The modified HPLC method has been adopted official first action.
We have constructed lambda/SPP1 hybrid phages by in vitro ligation of EcoRI fragments of the Bacillus subtilis phage SPP1 DNA to a lambdoid bacteriophage vector. EcoRI digestion of SPP1 generated 15 DNA fragments of which 13 could be cloned. The SPP1 DNA of such hybrids was stably maintained and replicated in Escherichia coli, as indicated by marker rescue experiments in B. subtilis. EcoRI fragment 1 of SPP1 could not be cloned although subfragments of fragment 1 resulting from spontaneous deletions which occurred during the cloning regime were consistently obtained. A region within EcoRI fragment 1 responsible for its incompatibility with replication in E. coli was defined by these experiments.
41 genes of SPP1 have been delineated by using complementation analyses of 75 conditionally lethal (ts and sus) mutations. The physical locations of these genes on the SPP1 chromosome have been determined by transfection/marker rescue experiments in which restriction endonuclease generated fragments of SPP1 DNA were used as donor DNA. The physical order of these fragments has been previously established (Ratcliff et al., 1979).
DNA molecules of B. subtilis phage SPP1 exhibit terminal redundancy and are partially circularly permuted. This was established by the hybridization of selected EcoRI restriction fragments to single strands of SPP1 DNA and by an analysis of the distribution of denaturation loops in partially denatured SPP1 DNA molecules. Deletions in SSP1 DNA are not compensated by an increase in terminally repetitious DNA. This finding, which is unique to SPP1, is discussed in terms of a modification of the Streisinger/Botstein model of phage maturation.
SPP1 DNA was cleaved by the restriction endonucleases, BglI, BglII, EcoRI, KpnI, SmaI, and SalI. The molecular weights of the DNA fragments obtained by single enzyme digestion or by consecutive digestion with two enzymes were determined by electron microscopic measurements of contour length and by gel electrophoresis. The major fragments from the six digests could be ordered to give a consistent restriction map of SPP1. The electropherograms of several digests indicated that certain fragments occurred in less than stoichiometric amounts or were heterogeneous in size. Such bands carried a major part of radioactivity, when SPP1 DNA was terminally labelled with P32 prior to degradation by restriction enzymes. These results, and studies of the effect of exonuclease III treatment on restriction enzyme patterns define the terminal restriction fragments. All data obtained support the conclusion drawn in the preceding paper (Morelli et al., 1978 b) that the SPP1 genome is terminally redundant and partially circularly permuted.
Explore the source record for details and available documents.