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Biomedical subjects

B Krämer

Publications and source records attributed to B Krämer.

At least 19 recordsLinked to original sources
PubMed2006

[Pararectal mini-incision for strictly retroperitoneal nephrectomy in living kidney donation].

PURPOSE: In this study we present the technique of a strictly retroperitoneal donor nephrectomy via a pararectal mini-incision. MATERIAL AND METHODS: Data of 34 living kidney donations were analyzed. All donors underwent a pararectal mini-incision and strictly retroperitoneal nephrectomy (MIDN). RESULTS: Total operation time, perioperative use of pain medication, length of hospital stay after successful mobilization, and return to full enteral nutrition and regular digestion were evaluated retrospectively. Total operation time for MIDN was 132+/-26 min. The total average application was 22.2+/-19.4 mg of opioid in morphine equivalent dosage (MED), 7.7+/-6.1 g metamizol, and 512+/-325 mg NSAR during hospital stay, which was 4.9+/-1.4 days. Patients were mobilized primarily 2.9+/-8.0 h after surgery. Mobility was achieved 33.8+/-15.8 h after surgery. Enteral nutrition with fluids was started after 1.9+/-7.0 h, full enteral nutrition was accomplished after 37.4+/-19.0 h, and normal digestion returned 58.6+/-23.0 h after the procedure. CONCLUSIONS: The strictly retroperitoneal nephrectomy via a mini-incision is an elegant, minimally traumatic, safe, and quickly learnable method, resulting in short hospital stays, good cosmetic results, and a low grade of complications.

Adult↗
PubMed2006

Massive cavernous lymphangioma of the breast and thoracic wall: case report and literature review.

Lymphangiomas are benign lesions but are associated with high morbidity when they become very large, occur in critical locations, or when surgically removed, develop secondary wound infections. Almost all lesions require surgical treatment. Complete excision is curative; however, relapses must be anticipated with incomplete excision. We report the case of a patient with a long history of massive cavernous lymphangioma of the breast and thoracic wall extending into the axilla in whom complete excision was not possible.

Adult↗
PubMed2004

Laparoscopic enterolysis before adjuvant radiotherapy in a case of endometrial cancer.

CASE: A 33-year-old woman presenting with endometrial cancer stage FIGO Ic. After hysterectomy, bilateral oophorectomy and lymph node dissection, combined radiotherapy was indicated. Computer tomography scan was performed to plan radiotherapy and large bowel adhesions were found. To prevent bowel complications during radiation therapy, laparoscopic enterolysis of the adhesions was performed. We were able to start and apply radiation therapy only 22 days after initial laparotomy. Our patient had a history of deep vein thrombosis as a result of oral contraceptive medication. The endoscopic treatment enabled us to shorten the time of immobilization and bed rest substantially. CONCLUSION: Laparoscopy is an appropriate method to prevent complications due to radiotherapy.

Adult↗
PubMed2002

In vitro determination of specific toxicity in tetanus vaccines.

Tetanus vaccine is prepared from detoxified tetanus neurotoxin. To ensure the absence of residual toxin activity or to exclude the reversion to toxicity reliable control testing is based on in vivo methods, because no in vitro assay provides the required specificity and sensitivity. Tetanus neurotoxin is a 150 kDa protein produced by Clostridium tetani. The 50 kDa light chain of this neurotoxin belongs to the family of zinc metalloproteases. It cleaves synaptobrevin, a small synaptic vesicle protein, which is involved in neuroexocytosis, at the single Q76-F77 peptide bond. To develop a sensitive in vitro assay capable of quantifying the proteolytic activity of this toxin, we used as substrate a recombinant fragment of synaptobrevin2 (1-97). For detecting the cleavage products a peptide antibody raised against the N-terminal cleavage site was used. In Western Blot analysis only the cleaved substrate was detected while the uncleaved substrate showed no signal. In different approaches, recombinant synaptobrevin was either (i) bound to a microtitre plate, reduced toxin was added and the N-terminal cleavage product was detected by a specific antibody or (ii) the cleavage was performed in test tubes, the samples were transferred to a microtitre plate and immobilised cleavage products were detected. When toxoid or crude toxin is used, non-specific cleavage of synaptobrevin substrate occurs. Depending on the toxoid used different patterns of degradation of substrate are visible in Western Blots. Different protease inhibitors and reaction conditions seem to have an effect on the inhibition of this non-specific cleavage.

Amino Acid Sequence↗
PubMed2001

Relative frequency of malaria pigment-carrying monocytes of nonimmune and semi-immune patients from flow cytometric depolarized side scatter.

BACKGROUND: Recently, it was observed that malaria can be detected by performing automated complete blood count analysis including depolarization measurement of scattered laser light. To explain large discrepancies in sensitivity and specificity observed in semi-immune and nonimmune malaria patients, we determined the relative frequencies of malaria pigment-carrying monocytes (PCM) by flow cytometric measurements combined with rare event analysis. METHODS: An experimental cell-sorting unit utilizing argon, krypton, and helium-neon lasers measured the relative frequencies of leukocytes of malaria patients. Single white blood cells showing high intensity in their depolarized side scatter were sorted for subsequent microscopic analysis. RESULTS: From microscopic inspection of sorted cells, we identified malaria PCM as a distinct cluster in scatter diagrams that is well separated from normal leukocytes. For nonimmune patients, the average relative frequency of PCM is 1.5 x 10(-4) (median), for semi-immune patients 8.8 x 10(-4), and for malaria-negative persons 4.4 x 10(-6). Results derived from depolarized side scatter at 488, 633, or 647 nm agree well. Furthermore, malaria pigment-carrying neutrophilic granulocytes were identified microscopically after sorting. We discuss briefly how pigment-carrying neutrophils might be differentiated from normal leukocytes and PCM by using flow cytometry and measuring depolarized side scatter at two wavelengths. CONCLUSION: Our results confirm the feasibility of malaria detection by flow cytometry for semi-immune patients and extend malaria detection to nonimmune patients with low frequencies of PCM. High sensitivity and specificity for malaria detection were obtained.

Cell Separation↗
PubMed2000

Upright posture influences salivary cortisol.

This study was designed to investigate the influence of posture on salivary cortisol concentrations in healthy volunteers. In a balanced cross-over design 24 subjects were exposed at 1 week intervals to different body positions (sitting [S], lying [L] upright [U]) for 20 min in each condition. Before, during and after the experimental treatment measures of blood pressure, heart rate and saliva samples for determining the free fraction of cortisol were obtained. Furthermore, at corresponding time points a questionnaire on emotional states was completed. In addition, subjects were requested to complete personality questionnaires before the experiment and to rate their emotional states during saliva sampling. Results clearly indicate that the circadian decrease of cortisol concentrations was present only in the conditions [S] and [L] whereas in [U] salivary cortisol concentrations increased significantly. As expected, heart rate accelerations associated with a marked reduction of systolic blood pressure were observed in [U]. To further examine the relationship between hormonal and cardiovascular responses as indicators of autonomic activation, correlations between change scores were computed indicating that a relationship between cardiovascular responses and cortisol increases is not restricted to [U]. Positive correlations were observed between changes in systolic blood pressure and changes in cortisol concentrations in both conditions [U] and [L]. Posture does not affect emotional states indicating independence between posture induced physiological responses and experienced discomfort. Posture therefore should be adequately controlled, since those non-specific increases of hormones may interfere with state or trait dependent responses. Data are discussed with respect to the importance to control for posture in field and experimental studies and to possible mechanisms of posture induced changes in cortisol.

Anxiety↗
PubMed1999

Nuclear hourglass technique: an approach that detects electrically open nuclear pores in Xenopus laevis oocyte.

Nuclear pore complexes (NPCs) mediate both active transport and passive diffusion across the nuclear envelope (NE). Determination of NE electrical conductance, however, has been confounded by the lack of an appropriate technical approach. The nuclear patch clamp technique is restricted to preparations with electrically closed NPCs, and microelectrode techniques fail to resolve the extremely low input resistance of large oocyte nuclei. To address the problem, we have developed an approach for measuring the NE electrical conductance of Xenopus laevis oocyte nuclei. The method uses a tapered glass tube, which narrows in its middle part to 2/3 of the diameter of the nucleus. The isolated nucleus is sucked into the narrow part of the capillary by gentle fluid movement, while the resulting change in electrical resistance is monitored. NE electrical conductance was unexpectedly large (7.9 +/- 0.34 S/cm(2)). Evaluation of NPC density by atomic force microscopy showed that this conductance corresponded to 3.7 x 10(6) NPCs. In contrast to earlier conclusions drawn from nuclear patch clamp experiments, NPCs were in an electrically "open" state with a mean single NPC electrical conductance of 1.7 +/- 0.07 nS. Enabling or blocking of active NPC transport (accomplished by the addition of cytosolic extracts or gp62-directed antibodies) revealed this large NPC conductance to be independent of the activation state of the transport machinery located in the center of NPCs. We conclude that peripheral channels, which are presumed to reside in the NPC subunits, establish a high ionic permeability that is virtually independent of the active protein transport mechanism.

Animals↗
PubMed1998

The spectroscopic analysis, inhibition and binding studies demonstrate the equivalence of Erythrina caffra trypsin inhibitor and the recombinant substitution variant recSerETI.

A recombinant substitution mutant (recSerETI) of the Erythrina caffra trypsin inhibitor, with the N-terminal valine residue substituted by serine, was produced in E. coli and compared to the wildtype protein (wtETI) with respect to physicochemical and functional properties. The spectral properties, including UV absorbance, fluorescence emission and circular dichroism, were indistinguishable. Furthermore, the inhibitory activities of the two proteins regarding the inhibition of trypsin, chymotrypsin, tissue plasmininogen activator (t-PA) and reteplase (BM 06.022, t-PA deletion variant comprising the kringle 2 and the protease domains, isolated from transformed E. coli cells) and the affinity of the immobilized inhibitors for reteplase were closely similar. Five repetitive cycles of guanidinium chloride (GdmCl)-induced denaturation-renaturation yield the native mutant protein with its inhibitory activity fully restored. The only difference between the wildtype and the mutant protein refers to the intrinsic stability. Comparing the pH- and GdmCl-dependent transitions, as well as the thermal denaturation, recSerETI exhibits decreased stability compared to the wildtype protein. The pH range of stability is shifted from pH 1-9.5, for wtETI, to pH 2-9, for recSerETI; similarly the GdmCl-induced denaturation is found to occur at a GdmCl half concentration of 3.7 M instead of 4.5 M; in both cases the renaturation exhibits strong hysteresis. The mid-point of the thermal unfolding transition of the mutant protein is at approximately 65 degrees C, as compared to approximately 75 degrees C for the wildtype protein.

Amino Acid Substitution↗
PubMed1998

Down-regulation of expression of a pupal cuticle protein gene by transcriptional and posttranscriptional control mechanisms during metamorphosis in Galleria.

Down-regulation of expression of a pupal cuticle protein gene (GmPCP52) was investigated during metamorphosis in Galleria during normal development and in response to 20-hydroxyecdysone (20 E) and a juvenile hormone analogue (epofenonane). The developmental profile of GmPCP52 transcription was traced by nuclear run-on transcription assays. Transcription of the GmPCP52 gene is highest shortly after pupal ecdysis. There is a rapid decline between a pupal age of 12 and 18 h. Transcription becomes undetectable at 24 h. 20 E accelerates cessation of transcription, but induces a short second period of GmPCP52 transcriptional activity. Epofenonane prolongs transcription and induces a second round of transcriptional activity in relation to the synthesis of a second pupal cuticle. Analysis of changes in poly(A) tail length of GmPCP52 mRNA demonstrated control of expression at the level of mRNA translatability and stability. At 6 to 9 h poly(A) tails of GmPCP52 mRNA have lengths of 70 to 170 A-residues. From 9 h on mRNA with about 50 As accumulates. This material is regarded as translationally inactive. From 18 h on, further poly(A) shortening and degradation of the transcript occurs. Again, 20 E has an accelerating effect. In accordance with the results of the run-on experiments, there is a second increase in GmPCP52 mRNA with poly(A) tail lengths greater than 50 A. Epofenonane causes delay but does not prevent the changes observed in untreated animals. The results demonstrate, that expression of the GmPCP52 gene is regulated at the level of transcription, translation, as well as transcript accumulation and degradation. Targets of hormonal action are discussed.

Animals↗
PubMed1997

Acute hypoxia stimulates renin secretion and renin gene expression in vivo but not in vitro.

This study aimed at examining the influence of acute hypoxia on renin secretion and renin gene expression in the kidney. To this end, male Sprague-Dawley rats were exposed to severe hypoxic stress (8% O2) or to carbon monoxide (0.1% CO) for 6 h, and plasma renin activity (PRA) and renal renin mRNA levels were determined. PRA values increased from 3 to 13 and 10 ng angiotensin I x h(-1) x ml(-1), and renin mRNA levels increased by 120 and 100% during hypoxia and CO, respectively. Lowering the PO2 from 150 to 20 or 7 mmHg in the gas atmosphere of primary cultures of renal juxtaglomerular cells had no influence on renin secretion and renin gene expression after 6 and 20 h. Our findings thus suggest that both arterial and venous hypoxia can be powerful stimulators of renin secretion and renin gene expression in vivo. Because renal denervation did not prevent stimulation of the renin system by hypoxia, the effect could be indirectly mediated via the baroreceptor-macula densa mechanism. Another potential mediator of the effect could be circulating catecholamines, since we found that plasma norepinephrine increased from 0.7 to 1.5 and 2.4 ng/ml and plasma epinephrine increased from 0.3 to 1.4 and 2.7 ng/ml during hypoxia and CO inhalation, respectively.

Analysis of Variance↗
PubMed1996

Function of the p55 tumor necrosis factor receptor "death domain" mediated by phosphatidylcholine-specific phospholipase C.

Tumor necrosis factor (TNF) is a pleiotropic mediator of inflammation that has been implicated in the pathogenesis of devastating clinical syndromes including septic shock. We have investigated the role of a TNF-responsive phosphatidylcholine-specific phospholipase C (PC-PLC) for the cytotoxic and proinflammatory activity of TNF. We show here that the cytotoxicity signaled for by the so-called "death domain" of the p55 TNF receptor is associated with the activation of PC-PLC. The xanthogenate tricyclodecan-9-yl (D609), a specific and selective inhibitor of PC-PLC, blocked the cytotoxic action of TNF on L929 and Wehi164 cells. In vivo, D609 prevented both adhesion molecule expression in the pulmonary vasculature and the accompanying leukocyte infiltration in TNF-treated mice. More strikingly, D609 protects BALB/c mice from lethal shock induced either by TNF, lipopolysaccharide, or staphylococcal enterotoxin B. Together these findings imply PC-PLC as an important mediator of the pathogenic action of TNF, suggesting that PC-PLC may serve as a novel target for anti-inflammatory TNF antagonists.

Animals↗
PubMed1996

The German Glomerulonephritis Therapy Study: 10 years of controlled randomized trials for the treatment of idiopathic glomerulonephritis.

The German Collaborative Glomerulonephritis Therapy Study, which celebrated its 10th anniversary in 1996, has collected data on more than 1,000 patients with biopsy-proven glomerulonephritis. 929 patients could be evaluated and 500 were treated according to at least one of various protocols developed for a randomized controlled trial. Current results show that prednisolone is effective in minimal-change nephropathy, and in combination with other immunosuppressants it can reduce proteinuria in individual cases of focal and segmental glomerulosclerosis, membranous glomerulonephritis and nephrotic IgA nephropathy. The majority of tested treatment protocols did not prove to be superior to symptomatic therapy for long-term outcome.

Adolescent↗
PubMed1995

Regulation of the human TNF promoter by the transcription factor Ets.

Tumor necrosis factor (TNF) affects the growth, differentiation, and function of a multitude of cell types and is viewed as a potent mediator of inflammation and cellular immune responses. In order to delineate functional domains that control TNF gene transcription, we have analyzed a 5' flanking region of the human TNF promoter spanning base pairs -115 to -98. This region contains a PEA3/Ets-1 binding motif 5' GAGGA 3' in direct juxtaposition to an AP-1/ATF-like palindromic sequence motif 5' TGAGCTCA 3'. Specific binding of Ets and Jun to their respective elements is demonstrated by competition analysis as well as by supershift assays. As shown by promoter deletion analysis, these two binding sites were essential for both basal promoter activity and responsiveness to the phorbol ester phorbol 12-myristate 13-acetate. Co-transfection of c-ets or c-jun expression plasmids along with TNF promoter-CAT reporter constructs revealed the participation of both transcription factors in the regulation of TNF gene transcription. Correspondingly, site-specific mutation of either Ets or Jun sites led to a complete loss of responsiveness to the respective transcription factor. These data suggest an essential role of Ets for the activation of TNF gene transcription.

Base Sequence↗
PubMed1995

Molecular cloning and characterization of human kinectin.

We have identified a human cDNA that is homologous to the chicken kinectin, a putative receptor for the organelle motor kinesin. The human cDNA clone hybridized to a single 4.6-kb mRNA species that codes for a protein of 156 kDa molecular mass. The predicted primary translation product contains an N-terminal transmembrane helix followed by a bipartite nuclear localization sequence and two further C-terminal leucine zipper motifs. In addition, the aminoacid sequence revealed a large region (327-1362) of predicted alpha-helical coiled coils. A monoclonal antibody CT-1 raised against a GST-kinectin fusion protein produced a perinuclear, endoplasmic reticulum-like staining pattern in diverse cell types from different species, indicating evolutionary conservation. Monoclonal antibody CT-1 and anti-chicken kinectin antibodies cross-reacted both in Western blotting and immunoprecipitation with a 160-kDa protein, confirming the antigenic identity of this 160-kDa protein with chicken kinectin. Epitope tagging studies revealed that the nuclear localization sequence motif of kinectin is not functional. Furthermore, a truncated kinesin cDNA lacking the N-terminal hydrophobic domain revealed a nonspecific cytoplasmic staining pattern. Together the data suggest that kinectin is an integral membrane protein anchored in the endoplasmic reticulum via a transmembrane domain.

Amino Acid Sequence↗
PubMed1995

Superantigen-induced transcriptional activation of the human TNF gene promoter in T cells.

Superantigens, such as staphylococcal enterotoxins (SE), cause food poisoning and shock, which is mediated at least in part by TNF. We have examined the mechanism of superantigen-induced activation of the TNF gene promoter in primary human peripheral blood T lymphocytes and in the leukemic T cell line Jurkat. Like stimulation of the T cell receptor complex through CD3 ligation, SEB induces binding of nuclear proteins to Egr- and Jun/ATF-related consensus sequences present between nucleotides -170 and -100 of the TNF promoter 5' flanking region. By cotransfection of Jurkat T cells with constructs containing TNF promoter deletion mutants linked to a CAT reporter gene, it is shown that superantigens can activate transcription from these two adjacent ETs and Jun/ATF binding elements. Superantigen-induced binding of Egr-1 and Jun/ATF is markedly reduced by okadaic acid, suggesting that phosphatases are involved in the signaling of SE. When compared to CD3 ligation, superantigens activate the TNF promoter more potently, which is likely due to costimulatory signals provided by superantigen presenting cells.

Animals↗
PubMed1994

Characterization of an Krox-24/Egr-1-responsive element in the human tumor necrosis factor promoter.

We have analyzed in various human leukemic cell lines a previously unrecognized region within the human TNF gene promoter that contains the sequence motif 5'-CCGCCCCCGCG-3'. This GC-rich sequence maps to bps -170 and -160 of the TNF gene. Electrophoretic mobility shift assays (EMSA) combined with methylation interference analysis revealed the binding of two distinct proteins with overlapping recognition sites. Supershift assays identified the constitutive transcription factor Sp1 and the immediate-early growth-response transcription factor Egr-1/Krox-24. Interestingly, this Egr-1-related factor was induced by PMA but not by TNF. The TNF gene GC-rich sequence conferred PMA responsiveness when linked to a heterologous minimal c-fos promoter. To examine the involvement of Egr-1/Krox-24 in TNF gene regulation, a Krox-24 expression vector was used, pSCTKr24. In Jurkat T cells pSCTKr24 stimulated pTNF-286CAT that contains sequences -286 to +34 of the human TNF gene fused to the chloramphenicol acetyltransferase (CAT) gene. Moreover, pSCTKr24 also stimulated the TNF gene GC-rich sequence linked to the minimal c-fos promoter. However, deletion of this site did not result in markedly reduced TNF promoter activity, suggesting that the Egr-1/Krox-24 response element may play an auxiliary role in TNF gene regulation.

Base Sequence↗
PubMed1991

The efficacy of diuretics in acute and chronic renal failure. Focus on torasemide.

Loop diuretics in high doses are the drugs of choice in the treatment of both acute renal failure (ARF) and chronic renal failure (CRF). Their pharmacokinetic and pharmacodynamic properties give them a high efficacy, even in severely compromised renal function. The serum elimination half-life and duration of action of most loop diuretics are dependent on the glomerular filtration rate and are therefore prolonged in renal failure. Torasemide, a new high ceiling and long acting loop diuretic, is as potent as furosemide (frusemide) in patients with advanced renal failure. Unlike other loop diuretics, the half-life and duration of action of torasemide are not dependent on renal function and the parent drug does not accumulate in renal failure. The extent of metabolism is clinically negligible. A number of studies have demonstrated the efficacy of furosemide, bumetanide, piretanide and torasemide in patients with ARF and CRF. When compared with the other loop diuretics, torasemide has the following advantages: a longer half-life independent of renal function, no indications of toxic side effects and apparently less influence on calciuresis.

Acute Kidney Injury↗