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Biomedical subjects

D Brehmer

Publications and source records attributed to D Brehmer.

15 recordsLinked to original sources
PubMed2002

[Oncocytic adenocarcinoma of the submandibular gland].

BACKGROUND: Malignant oncocytic tumors rarely occur in major salivary glands and generally account for < 1% of all salivary tumors. There is no difference of both sexes and appearing mainly between 50 and 60 years of age. They comprise oncocytes, which are epithelial cells with abnormally formed cytoplasm and acidophilic granular cytoplasma. In the process of the malignant transformation the coexistence from oncocytic rests and untypical oncocytic carcinoma portions can be seen. The tumors show no capsule and an infiltrative local growth with perineural and vascular expansions. PATIENT AND METHOD: A rare case of a 59-year-old man with malignant oncocytoma is presented. The tumor was found in the left submandibular gland with one enlarged lymph node near by. RESULT AND CONCLUSIONS: A general overview of the available literature and the histological classification of oncocytomas is given. Therapy consists of surgical resection and radiotherapy. Close clinical controls are necessary.

Adenocarcinoma↗
PubMed2001

Binding specificity of Escherichia coli trigger factor.

The ribosome-associated chaperone trigger factor (TF) assists the folding of newly synthesized cytosolic proteins in Escherichia coli. Here, we determined the substrate specificity of TF by examining its binding to 2842 membrane-coupled 13meric peptides. The binding motif of TF was identified as a stretch of eight amino acids, enriched in basic and aromatic residues and with a positive net charge. Fluorescence spectroscopy verified that TF exhibited a comparable substrate specificity for peptides in solution. The affinity to peptides in solution was low, indicating that TF requires ribosome association to create high local concentrations of nascent polypeptide substrates for productive interaction in vivo. Binding to membrane-coupled peptides occurred through the central peptidyl-prolyl-cis/trans isomerase (PPIase) domain of TF, however, independently of prolyl residues. Crosslinking experiments showed that a TF fragment containing the PPIase domain linked to the ribosome via the N-terminal domain is sufficient for interaction with nascent polypeptide substrates. Homology modeling of the PPIase domain revealed a conserved FKBP(FK506-binding protein)-like binding pocket composed of exposed aromatic residues embedded in a groove with negative surface charge. The features of this groove complement well the determined substrate specificity of TF. Moreover, a mutation (E178V) in this putative substrate binding groove known to enhance PPIase activity also enhanced TF's association with a prolyl-free model peptide in solution and with nascent polypeptides. This result suggests that both prolyl-independent binding of peptide substrates and peptidyl-prolyl isomerization involve the same binding site.

Amino Acid Sequence↗
PubMed2001

Bag-1M accelerates nucleotide release for human Hsc70 and Hsp70 and can act concentration-dependent as positive and negative cofactor.

The cytosol of mammalian cells contains several Hsp70 chaperones and an arsenal of cochaperones, including the anti-apoptotic Bag-1M protein, which regulate the activities of Hsp70s by controlling their ATPase cycles. To elucidate the regulatory function of Bag-1M, we determined its influence on nucleotide exchange, substrate release, ATPase rate, and chaperone activity of the housekeeping Hsc70 and stress-inducible Hsp70 homologs of humans. Bag-1M and a C-terminal fragment of it are potent nucleotide exchange factors as they stimulated the ADP dissociation rate of Hsc70 and Hsp70 up to 900-fold. The N-terminal domain of Bag-1M decreased the affinity of Bag-1M for Hsc70/Hsp70 by 4-fold, indicating a modulating role of the N terminus in Bag-1M action as nucleotide exchange factor. Bag-1M inhibited Hsc70/Hsp70-dependent refolding of luciferase in the absence of P(i). Surprisingly, under physiological conditions, i.e. low Bag-1M concentrations and presence of P(i), Bag-1M activates the chaperone action of Hsc70/Hsp70 in luciferase refolding. Bag-1M accelerated ATP-triggered substrate release by Hsc70/Hsp70. We propose that Bag-1M acts as substrate discharging factor for Hsc70 and Hsp70.

Adenosine Diphosphate↗
PubMed2001

Tuning of chaperone activity of Hsp70 proteins by modulation of nucleotide exchange.

The Hsp70 chaperone activity in protein folding is regulated by ATP-controlled cycles of substrate binding and release. Nucleotide exchange plays a key role in these cycles by triggering substrate release. Structural searches of Hsp70 homologs revealed three structural elements within the ATPase domain: two salt bridges and an exposed loop. Mutational analysis showed that these elements control the dissociation of nucleotides, the interaction with exchange factors and chaperone activity. Sequence variations in the three elements classify the Hsp70 family members into three subfamilies, DnaK proteins, HscA proteins and Hsc70 proteins. These subfamilies show strong differences in nucleotide dissociation and interaction with the exchange factors GrpE and Bag-1.

Adenosine Diphosphate↗
PubMed2001

[Schwannoma of the tongue].

BACKGROUND: Schwannoma, in the English literature mostly called neurilemmoma, are well known in the ear-nose-and-throat-medicine as benign tumors of the nerve-sheath, for example as neuroma of the acoustic nerve. They are seldom found at other peripheral nerves of the head. The localisation in the tongue has so far only been described in some individual cases. CASE REPORT: We present a case of a 28-year-old woman with a schwannoma of the tongue, measuring 4.0 x 2.2 x 3.2 cm. The case history and the radiological investigations suggested a malignant tumor. During the operation the lump revealed itself as being encapsulated. Under the histological examination it was discovered to be a Schwannoma. CONCLUSIONS: We would like to add a further case of a schwannoma of the tongue to the so far published cases, thus allowing this possibility to be considered in general diagnosis.

Adult↗
PubMed2000

[Ear dysfunction due to air bag detonation?].

Air bags are among the latest developments in extensive automobile safety systems. They successfully have saved the lives of car occupants in road accidents. Many additional injuries caused by air bags from minor to severe have been reported. With the help of two acceleration sensors, the electronic tuner amplifier records the vehicle's deceleration. This is the adequate trigger for air bag deployment, which creates an intense noise of up to 170 dB sound pressure level. This noise level can cause cochlear damage. We present two patients with otologic symptoms after spontaneous air bag deployment.

Adult↗
PubMed1999

[Diagnosis of postoperative dysphagia and aspiration. Fiberoptic-endoscopic controlled methylene blue drinking].

Postoperative swallowing disorders are common after such function-preserving surgery as conventional resections or endoscopic laser procedures for carcinomas of the larynx and hypopharynx. In most cases a reduction in motility of the pharyngeal muscles and sensory impairment of the pharyngeal and laryngeal regions can occur because of postoperative tissue abnormalities, including scarring due to the healing process. We have used fiberoptic endoscopic examinations with methylene blue to analyze postoperative swallowing and observe whether staining or aspiration occurs. By so doing, we have improved postoperative swallowing in 25 patients after extended surgery for cancer and were able to detect or exclude aspiration. The advantages of this minimally invasive, non-stressful diagnostic procedure are discussed and can be important for further successful care after surgery.

Administration, Oral↗
PubMed1999

[Intraductal papilloma of the parotid gland].

BACKGROUND: This rare intraductal papilloma of the salivary glands is classified as an adenoma of the subgroup ductal papillomas. The nature of intraductal papillomas has not been fully researched. It is assumed that the intraductal papilloma arises from the excretory duct reserve cell population. Since the lesion was first described, 9 cases have been reported. CASE REPORT: An additional case of intraductal papillomas of the parotid gland is presented: a 62-year-old woman with a solid and well displaceable tumor of the left preauricular region. After a standard superficial parotidectomy was performed the histological examination revealed an intraductal papilloma. RESULT AND CONCLUSION: The case represents the first published case in German literature. This study presents a review of the literature and a discussion of the histopathologic characteristics and possible histogenesis of the intraductal papilloma. Regular follow-up has not revealed any recurrence of the disease 15 months after resection. The treatment of choice is local excision or removal.

Female↗
PubMed1998

[Incidence of endomycoses in the autopsy material of the Berlin Charité Hospital].

From 1970 to 1993, a total of 93 endomf1p4es confirmed by post-mortem examination was diagnosed in the autopsy material of the Berlin Charité, a large hospital with an average of 1,500 hospital beds and maximum medical care. These comprised 51 candidoses (54.8%), 24 aspergilloses (36.6%), five cryptococcoses (5.4%), one zygomycosis, 1 trichosporosis and one coccidioidomycoses. This corresponded to 0.7% of the 13,375 decreased persons autopsied during this period. The frequency of autopsy was 85.3%. In 3,770 cases (2,418 adults and 1,352 children), brain dissection was performed. An adequate clinical putative diagnosis was made in only six out of 28 patients (18 adults, 10 children) with histologically confirmed cerebral mycosis [11 candidoses (39.3%), 10 aspergilloses (35.7%), five cryptococcoses (17.9%), one trichosporosis and one coccidioidomycosis]. About 80% of the mycoses of the CNS thus remained undetected while the patients were alive. Against the background of the continuing reduction in the frequency of autopsy in the Federal Republic of Germany, the observations made in the present paper underscore the demand for improved efficiency of mycological in-vivo diagnoses in the hospital and laboratory.

Adult↗
PubMed1989

Effect of cyclosporin A on carbohydrate metabolism in the rat.

Liver and kidney carbohydrate metabolism was investigated in rats treated with daily doses of 15 mg/kg body weight cyclosporin A (CyA) for 2 and 8 weeks or of 50 mg/kg body weight CyA for 2 weeks. The higher dosage caused significantly reduced liver glycogen and liver glycogen synthetase activity (of both active I-form and total enzyme activity), whereas the activity of the glycogen-degrading enzyme phosphorylase (active a-form and total activity) remained unchanged. Plasma glucose and glucagon levels, as well as blood ketone bodies of these animals, increased significantly and plasma insulin decreased. In contrast, kidney glycogen and glucose content were higher in rats treated with 50 mg CyA, probably due to enhanced ketone body utilization. Reduced liver glycogen synthetase activity was also found in rats treated with 15 mg CyA. Our data suggest that hypoinsulinemia, induced by CyA, might be a contributing factor to the hyperglycemia, which is mainly due to inhibition of liver glycogen synthesis.

Animals↗
PubMedDate not supplied

Malignant ectomesenchymoma of the nose. Case report and review of the literature.

To the best of our knowledge, a malignant ectomesenchymoma of the nose has not yet been reported. This rare tumour is composed of a mesenchymal element--usually a rhabdomyosarcoma--and a neuroectodermal element, often a neuroblastoma or a malignant schwannoma. Most malignant ectomesenchymomas have been found in children (mainly boys), but 5 adult cases, including our case, have also been reported. A 62-year-old man presented with a nasal obstruction on the right side of the nose. Diagnostic nasal endoscopy revealed a mass in the dorsal part of the right nasal cavity, which was treated by endoscopic surgery. The postoperative course was uneventful, and subsequent radiotherapy well tolerated. Since rhabdomyosarcoma is the most common component of this neoplasm, the treatment protocol for rhabdomyosarcoma would have appeared appropriate. This report reviews the literature, summarises the pathological features and possible histogenesis of the tumour, and outlines recommended treatments for malignant ectomesenchymoma.

Combined Modality Therapy↗