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Biomedical subjects

B Schrader

Publications and source records attributed to B Schrader.

At least 37 records · Page 2Linked to original sources
PubMed1995

Comparative acute effects of adenosine and prostacyclin in primary pulmonary hypertension.

Vasodilators have been a main focus of therapy for primary pulmonary hypertension. Adenosine and prostacyclin have been shown to reduce pulmonary vascular resistance acutely in these patients. In order to compare the acute hemodynamic effects of adenosine and prostacyclin, ten patients with severe primary pulmonary hypertension, unresponsive to medical therapy, were studied. After baseline hemodynamics were obtained, an adenosine infusion, 50 to 100 ng/kg/min, was begun and titrated to the maximum tolerated dose. Hemodynamics were allowed to return to baseline, and thereafter, a prostacyclin infusion was begun at 2 ng/kg/min, and titrated to the maximum tolerated dose. Overall, adenosine (200 +/- 53 ng/kg/min) produced a 33 +/- 18% (p < 0.001) fall in pulmonary vascular resistance and a 52 +/- 25% (p < 0.001) increase in cardiac output with no effect on pulmonary or systemic arterial pressures. Prostacyclin (8 +/- 4 ng/kg/min) caused a 22 +/- 18% (p < 0.01) fall in pulmonary vascular resistance and a 25 +/- 26% (p < 0.05) increase in cardiac output with a 14 +/- 6% (p < 0.001) decrease in systemic arterial pressure, but no change in pulmonary arterial pressure. The effects of adenosine and prostacyclin on pulmonary vascular resistance were similar (r = 0.70, r2 = 0.49, p = 0.02). Adenosine and prostacyclin have similar hemodynamic effects acutely in primary pulmonary hypertension. Adenosine may be useful as a test of the potential for long-term prostacyclin therapy in patients with primary pulmonary hypertension.

Adenosine↗
PubMed1994

Raman spectroscopic study of the blue copper protein halocyanin from Natronobacterium pharaonis.

Halocyanin, a blue copper protein from Natronobacterium pharaonis was studied by Raman spectroscopic techniques. Near-infrared Fourier transform Raman spectra, which for the first time have been employed to study copper proteins in both oxidation states, display the Raman bands of the protein and, in the oxidized state, also the preresonance-enhanced bands of the copper center. The frequency of the amide I band at 1676 cm-1 indicates a predominant beta-sheet protein structure, which is typical for small blue copper proteins. The Raman spectra provide no evidence for major redox-linked changes of the secondary structure. Resonance Raman spectra of the oxidized protein obtained upon excitation close to the 600-nm absorption band were measured in the pH range between 7.7 and 4.5. The vibrational band pattern in the Cu-cysteine stretching region is closely related to that of azurin, indicating far-reaching similarities of the coordination geometry of the copper center in both proteins. Significantly lower frequencies, however, are noted for the Cu-histidine stretches, which appear as a closely spaced doublet at ca. 260 cm-1. Lowering the pH to 4.5 leads to an increase of this band splitting with one component shifting down to 247 cm-1. This downshift is attributed to the rupture of a hydrogen bond between one of the histidine ligands and a nearby carboxyl group, which becomes protonated at such a low pH. On the other hand, no major changes in the Cu-cysteine stretching region are noted at pH 4.5, implying that the coordination geometry remains largely unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Azurin↗
PubMed1993

Intercellular immune adhesion molecules in human liver transplants: overview on expression patterns of leukocyte receptor and ligand molecules.

Recently it has become clear that the inflammatory response of immune cells to target cells and extracellular matrix is regulated by several receptor-ligand molecules. Three main classes of molecules mediating intercellular adhesion and activation processes have been identified: the integrin, immunoglobulin and selectin families. This study surveys the expression of adhesion molecules on resident and infiltrating cells in human liver grafts. The patterns of cellular expression and inducibility in different pathological conditions of the graft are described. Our results show organ-specific regulation of the different adhesion molecules during alloreactive reactions and other types of inflammatory reactions. No rejection-specific patterns were detected on comparison with reperfusion damage or infectious transplant inflammation. Major differences were noted in the composition of the portal tract and sinusoid with regard to endothelial and parenchymal cell expression of cell-cell and cell-matrix adhesion molecules. Intravascular and interstitial differences in the expression patterns of leukocyte adhesion receptors support a concept of stepwise expression. The implications for the appearance of inflammatory reactions in human liver in immunosuppressive and therapeutic interventions are discussed.

Cell Adhesion Molecules↗
PubMed1993

Expression patterns of leukocyte adhesion ligand molecules on human liver endothelia. Lack of ELAM-1 and CD62 inducibility on sinusoidal endothelia and distinct distribution of VCAM-1, ICAM-1, ICAM-2, and LFA-3.

Vascular expressed adhesion molecules mediate leukocyte reactivity and activation by receptor-ligand binding. A number of different ligand molecules have been identified to mediate the interaction between endothelial cells and leukocyte subpopulations. In this study, the tissue expression of ELAM-1, CD62 (PADGEM, GMP-140), VACM-1 (INCAM-110), ICAM-2, ICAM-1, and LFA-3 was analyzed on various liver endothelial cell types by immunohistology. The results reveal a differential expression of these molecules in normal liver and inflammation or rejection after liver transplantation. The selectins ELAM-1 and CD62 are basally expressed and inducible on portal tract endothelia (arterial and venous) and central vein endothelia with acute and chronic liver inflammation. Sinusoidal endothelia, however, lack this mechanism, even with severe inflammation, as in cases of irreversible rejection and sepsis. Portal and sinusoidal endothelia show a different expression and inducibility of VCAM-1, ICAM-1, ICAM-2, and LFA-3. The differences in expression of adhesion molecules on liver endothelial cell types may reflect their ability to regulate leukocyte trafficking and activation by means of the expression of specific ligand molecules. The inability of sinusoidal endothelia to express selectins may have implications for the pathophysiology of liver graft infiltration.

Cell Adhesion Molecules↗
PubMed1992

Fourier transform resonance Raman spectroscopy of phytochrome.

The Pr and Pfr forms of phytochrome in H2O and D2O have been studied by Fourier transform resonance Raman spectroscopy with near-infrared excitation (1064 nm). It is demonstrated that this technique is a powerful method for analyzing the chromophore structures of photosensitive pigments. The high spectral quality allows discussion of vibrational assignments based on an empirical approach using previously published data obtained from model compounds. The reduction in intensity of a high-frequency band assigned to the ring-C/D methine bridge vibration is an indication for the non-coplanarity of the ring D in Pfr. The high intensity of a C-H out-of-plane vibration also supports this hypothesis. In Pr, a broad peak at approximately 1100 cm-1 is assigned to an out-of-plane vibration of a strongly hydrogen-bonded pyrrole C=NH+ group. It is missing in Pfr, suggesting deprotonation of the corresponding ring during the transformation from Pr to Pfr.

Chemical Phenomena↗
PubMed1992

[Carcinoid of the middle ear: a rare tumor with biphasic differentiation. Case report with special reference to immunohistochemistry and electron microscopy].

Progressive unilateral sensorineural deafness and tinnitus developed in a 59-year-old woman over a 1-year period. Clinical examination showed a tumor mass which almost completely filled the tympanic cavity, and grew around the auditory ossicular chain. Histological findings revealed the tumor to be a primary carcinoid of the middle ear. Neuro-endocrine differentiation was confirmed immunohistochemically by positivity for neuron-specific enolase, chromogranin, pancreatic polypeptide and synaptophysin. Using electron microscopy, neuroendocrine granules could be visualized. In addition, both light and electron microscopy revealed that cells had an epithelial differentiation with mucin granules while immunohistochemistry showed a positivity for cytokeratins. The detection of intermediary filaments (immunohistochemically with vimentin and under electron microscopy) was unique to this neoplasm and has to be considered in distinguishing the carcinoid tumor from the papillary adenoma of the middle ear. Tumor prognosis is excellent with radical extirpation from the middle ear. In the case presented, there has been no evidence for either recurrence or metastases 10 months after surgical resection.

Biomarkers, Tumor↗
PubMed1991

Primary donor structure and interactions in bacterial reaction centers from near-infrared Fourier transform resonance Raman spectroscopy.

Preresonance Raman and resonance Raman spectra of the primary donor (P) from reaction centers of the Rhodobacter (Rb.) sphaeroides R26 carotenoidless strain in the P and P+ states, respectively, were obtained at room temperature with 1064-nm excitation and a Fourier transform spectrometer. These spectra clearly indicate that the chromophore modes are observable over those of the protein with no signs of interference below 1800 cm-1. The chromophore modes are dominated by those of the bacteriochlorophylls (BChl a), and it is estimated that, in the P state, ca. 65% of the Raman intensity of the BChl a modes arises from the primary donor. This permits the direct observation of a vibrational spectrum of the primary donor at preresonance with the excitonic 865-nm band. The Raman spectrum of oxidized reaction centers in the presence of ferricyanide clearly exhibits bands arising from a BChl a+ species. The magnitude of the frequency shift of a keto carbonyl of neutral P from 1691 to 1717 cm-1 upon P+ formation strongly suggests that one BChl molecule in P+ carries nearly the full +1 charge. Our results indicate that the unpaired electron in P.+ does not share a molecular orbital common to the two components of the dimer on the time scale of the resonance Raman effect (ca. 10(-13) s).

Fourier Analysis↗
PubMed1991

[Dosage errors and their prevention in intraocular SF6 injection for endotamponade in pneumatic retinopexy and after vitrectomy].

Sulfur hexafluoride (SF6) is used for internal tamponade during retinal detachment surgery. It is usually injected into the eye by a plastic syringe either with a sharp needle or by using the infusion system during pars plana vitrectomy. Although several suggestions exist for the appropriate application of intraocular SF6 and other perfluocarbons, a sudden postoperative rise in tension or hypotonia has been observed repeatedly. We simulated the preparation and application of mixtures of sulfur hexafluoride and air and analyzed possible mistakes. SF6 was quantitatively analyzed by infrared spectroscopy. SF6 does not rapidly diffuse out of capped plastic syringes made of polypropylene, as commonly employed in the Federal Republic of Germany. SF6 and air mix completely during aspiration. If the volume of microporefilters or tubes being used for preparation and instillation of mixtures of SF6 and air is ignored, this may result in a 20% deviation in SF6 concentration. Silicone tubes, which are widely used for the influsion during pars plana vitrectomy, are not recommended for the application of SF6. SF6 and fluorcarbones diffuse through silicone tubes and absorb and desorbe in the tube. Infusion lines made of polyethylene or polyvinylchloride, e.g. butterflies, should be preferred.

Dose-Response Relationship, Drug↗
PubMed1990

[Ultrasound-controlled fine needle biopsy of pathologic space occupying lesions in the head and neck area].

We report 121 fine-needle aspiration biopsies of tumours and lymph nodes of the head and neck guided by ultrasound. The average minimal diameter of the lesions was 1.2 cm; the smallest lymph node was adjacent to the carotid artery and had a diameter of 0.4 cm. There were no complications. Of the cytological results 96% were confirmed by histology or by the subsequent clinical course.

Biopsy, Needle↗
PubMed1989

[Therapy of facial paralysis in herpes zoster oticus with acyclovir].

In the present study patients suffering from facial nerve palsy caused by a herpes zoster oticus were treated with aciclovir. After therapy all patients could be controlled via clinical grading system and electromyographic observations. Aciclovir therapy did not yield any results superior to those obtained with other forms of therapy presented in the literature.

Acyclovir↗
PubMed1989

[Manifestations and therapy of malignant fibrous histiocytomas of the head and neck].

From 1982 through 1987, ten patients with malignant fibrous histiocytomas (MFH) in the head and neck area were treated at the ORL Department of the Central Hospital of Bremen. The primary tumor was situated in the region of the paranasal sinuses in six cases and in the parotid gland, the thyroid gland, the inferior maxilla, and the petrosal bone in one case, each. Nine patients were submitted to primary surgery. A postoperative irradiation was performed in four cases, and in four further cases this was done only when a recurrent tumor had been demonstrated. Three patients received a combined chemotherapeutical treatment. Eight patients died, the median survival time was 15 months. Besides local recurrences which occurred frequently, remote metastases are the decisive factor for the further evolution of the disease. The lung was the most common site of metastatic spread. Only two patients with MFH of the paranasal sinuses are living now without recurrence after an observation time of 24 and 36 months, respectively.

Combined Modality Therapy↗
PubMed1988

[Metastasis of cancer of the external ear].

Follow-up of 103 patients with squamous cell carcinomas of the auricula showed that 20 of them developed regional lymph node metastases. The effect of size, site and certain histological parameters on the occurrence of metastases was assessed. The incidence of metastases correlated with increasing size of the tumour.

Aged↗
PubMed1987

[Therapy of sudden deafness--naftidrofuryl (Dusodril) and pentoxifylline (Trental) compared].

In a prospectively randomized trial, conduced jointly by the University ENT Department, Göttingen, and the ENT Department of Zentralkrankenhaus St.-Juergen-Strasse, Bremen, the therapeutic efficiencies of naftidrofuryl and pentoxifyllin, both in combination with a basic medication (cortison, dextran), were compared in 151 patients with sudden deafness. Evaluation of the results revealed a decisive influence of cardiovascular risk factors (particularly vascular diseases) on the outcome of therapy. There was no difference between naftidrofuryl and pentoxifyllin with respect to therapeutic success. Since further improvement was evident 6 months later, long-term treatment is recommended for either substance. The therapeutic success rate of our own treatment schedule is not higher than that of other therapeutic schedules given in the literature.

Audiometry, Pure-Tone↗
PubMed1987

[Initial clinical experience using an interdisciplinary management concept for pregnant patients with liver damage].

Among 6,404 deliveries in 49 cases (0.8%) a liver disease was diagnosed in the course of pregnancy. The onset of the disease happened exclusively in the last trimester of pregnancy. In 36 pregnant women a hyperbilirubinaemia of diagnostic value was stated. As an informing diagnostic procedure the only determination of the alanine-aminotransferase activity has been proved to be sufficient. In every fifth pregnant woman the liver disease was observed in connection with a preeclampsia. The preterm delivery rate was 16.3%. An intrauterine growth retardation was found in 22.4% of women with hepatopathy during pregnancy. In 5 out of 34 patients asked for a post partum control a manifestation of the liver disease, respectively a cholecystopathia, was present and follow-ups were necessary. An interdisciplinary concept of treatment is emphasized to treat these pregnant women in cooperation with the specialist of internal medicine. Methodically an additional sheet of documentation is used, which contains important data of patients history and all obstetrical, clinical and laboratory results accompanying the pregnant woman during pregnancy and post partum controls.

Combined Modality Therapy↗
PubMed1986

[Course of pregnancy and labor following treatment of sterility].

Based on the pregnancy and delivery courses of 374 women having sterility histories, special features of the risk factor "state after sterility treatment" have been pointed out. A comparison with 2,474 primarily fertile women shows that the risk group is affected with the more frequent occurrence of impending abortion, gestosis and multiple pregnancy. 21.4% of pregnancies of previously sterile women had to be operatively terminated, while this figure in the control group was only 5.4%. Perinatal findings in the risk group showed a three-times higher rate of premature births, a more frequent occurrence of intra-uterine retardation and higher perinatal mortality. Gravidae after sterility treatment represent an inhomogeneous group of patients, individual care schemes are required for each patient.

Abortion, Spontaneous↗