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Biomedical subjects

D Albrecht

Publications and source records attributed to D Albrecht.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Overexpression of B7-1 amd B7-2 by LFA-1 positive lymphocytes in chronic inflammatory bowel diseases].

The B7/CD28 pathway is essential for initiating antigen-specific T-cell activation. LFA-1 (CD11a/CD18) is required for sufficient migration into inflammatory tissue. The aim of this study was to evaluate the role of B7 and LFA-1 in inflammatory bowel disease. Immunohistological single and double staining (PAP/APAAP) with monoclonal antibodies against HLA I/II, CD4, CD8, CD28, B7-1, B7-2, LFA-1 and CD68 were performed in tissue samples from patients with crohn's disease (n = 15), ulcerative colitis (n = 14), colorectal carcinoma (n = 5) and FAP (n = 3). The expression of B7-1 and B7-2 was generally much higher in ulcerative colitis and crohn's disease than in colorectal carcinoma and FAP. In crohn's disease multinucleated gigant cells in the granulomas express B7-1 and B7-2. Double staining showed a higher B7-1/B7-2 coexpression for CD4+ than for CD8+ T cells. In colitis ulcerosa and crohn's disease LFA-1 positive leucocytes showed a high coexpression of B7-1 and B7-2 in contrast to CD68 positive macrophages. These data suggest that overexpression of B7-1 and B7-2 on LFA-1 positive Leucocyts seems to play an important role in the pathogenesis of inflammatory bowel disease.

Adenomatous Polyposis Coli↗
PubMed1998

[Significant modification of the hyperthermic effect by starch microspheres (Spherex) of laser-induced hypertheria in the rat liver metastasis model].

This experimental study in an animal liver metastasis model (adenocarcinoma) investigated whether the "cooling effect" can be eliminated by temporary embolization with starch microspheres (Spherex) and the hyperthermic efficiency was improved. In this connection, groups of 15 test animals were treated with LITTmono, Embolizationmono or LITTembolization. In the LITTembolization group, 1/15 animals had vital tumor tissue after 24 h, 7 and 28 days, but tumor growth was found in the other 2 groups in 13/15 (LITTmono) and 14/15 (Embolization(mono)). These results demonstrate that the application of starch microspheres led to a significant increase in the hyperthermic effect of LITT under the selected testing conditions.

Adenocarcinoma↗
PubMed1998

[Endoscopic cholecystectomy as cost assessment--still a learning intervention?].

Economic considerations are putting increasing pressure on surgical departments to avoid intra- and postoperative complications and thus additional costs. Under this aspect, it was investigated whether laparoscopic cholecystectomy is a suitable training intervention for young prospective surgeons. These physicians in advanced training did not have a higher intra- or postoperative complication rate in a preselected patient population than senior physicians or specialists. The additional costs per surgical intervention due to longer operation times required by young physicians were acceptable so that laparoscopic cholecystectomy as a training intervention for young colleagues can be justified.

Cholecystectomy, Laparoscopic↗
PubMed1998

[Optimized laser-induced thermotherapy in treatment of liver metastases of colorectal carcinomas, an interdisciplinary responsibility--a clinical study].

In a clinical study, it was investigated whether local tumor control is attainable with laser-induced thermotherapy (LITT) in the treatment of colorectal liver metastasis tumors. Local control of tumor growth was obtainable in completely hyperthermic tumors. Due to the small and inhomogeneous patient population (n = 32), an assessment of the method regarding prognostic gain for the patient is not possible in such a short follow-up period.

Adult↗
PubMed1997

[Chronic right heart failure after implantation of a cava filter].

HISTORY AND CLINICAL FINDINGS: A 39-year-old woman complained of dyspnoea and increasing abdominal pressure sensation. A Greenfield filter had been implanted into her inferior vena cava (IVC) 4 years previously because of pulmonary embolism from a deep vein thrombosis after a hysterectomy with abscess formation. Physical examination revealed neck vein congestion, jaundiced sclerae, a tense abdominal wall, ascites and a soft machinery murmur in the paraumbilical region. INVESTIGATIONS: Transaminase activities were slightly raised (GOT 38 U/I, GPT 20 U/I), but total bilirubin and direct bilirubin were markedly elevated (2.9 mg/dl and 1.1 mg/dl, respectively). There was no evidence of cholestasis or decreased liver synthesis. Ultrasound showed marked dilatation of the IVC and hepatic veins, and echocardiography revealed right ventricular enlargement with grade II tricuspid regurgitation. Calculated pulmonary arterial systolic pressure averaged 50 mmHG. Colour-coded Doppler sonography demonstrated an aorto-caval shunt at the level of the filter in the IVC and penetration of a filter strut into the aortic lumen. TREATMENT AND COURSE: After removing the ascitic fluid by fluid and sodium restriction, and administration of an aldosterone antagonist and a loop diuretic, the A-V fistula was closed surgically and the filter removed. Three months after operation she was put on phenprocoumon (Quick value 20-30%). At the latest outpatient examination, 6 months after the operation, she was free of symptoms. CONCLUSION: As filter implantation in the IVC may produce severe complications, indications for it need to be demonstrated by further studies of its efficacy.

Adult↗
PubMed1997

Effects of angiotensin II and IV on geniculate activity in nontransgenic and transgenic rats.

Microiontophoretic ejection of angiotensin II and angiotensin IV in the vicinity of geniculate neurons was used to study the effects of these peptides on the discharge rate and the discharge pattern of extracellularly recorded activity. The main aim of the experiments was to study the effects of angiotensins in different strains of rats anesthetized with urethane (normotensive Wistar, normotensive Sprague-Dawley and hypertensive, transgenic (TGR(mREN2)27) rats). Both angiotensins mostly increased the spontaneous activity of angiotensin-sensitive geniculate neurons in all strains. Angiotensin II reduced the number of bursts in most neurons, whereas angiotensin IV significantly enhanced it. Inhibitory effects of angiotensins on spontaneous as well as on light-evoked activity could be effectively blocked by GABA(A) or GABA(B) receptor antagonists. Therefore, it can be supposed that angiotensin-containing afferent fibers innervate both projection and local circuit neurons of the dorsal lateral geniculate nucleus. In addition, angiotensin II suppressed excitation induced by glutamate receptor agonists in most neurons tested. Angiotensin-induced effects could be blocked by specific receptor antagonists. There were no significant differences in the effects of angiotensins in the various strains of rats, except for the latencies of the neuronal responses to the iontophoretic ejection of angiotensins.

Angiotensin II↗
PubMed1997

Excitatory action of angiotensins II and IV on hippocampal neuronal activity in urethane anesthetized rats.

The renin-angiotensin system of the mammalian brain seems to interfere with the process of cognition and has been associated with the hippocampal function in relation to mechanisms of learning and memory. In our investigation, the effects of angiotensin II (Ang II) and angiotensin IV (Ang II) on neuronal activity have been studied in the hippocampus of adult rats anesthetized with urethane. Excitatory effects of both angiotensins predominated over inhibitory effects. Angiotensins also induced an enhancement of burst discharges. These angiotensin-induced effects were blocked by the specific angiotensin antagonists. Our findings showed that the different effects of Ang II and Ang IV in behavioral studies are not similarly reflected in a different change of the discharge rate and/or pattern of hippocampal neurons after microiontophoretic administration of both substances.

Action Potentials↗
PubMed1997

Actions of angiotensin and lisinopril on thalamic somatosensory neurons in normotensive, non-transgenic and hypertensive, transgenic rats.

OBJECTIVE: To investigate the effects of angiotensin II on discharge rates of somatosensory thalamic neurons and whether these effects are altered in hypertensive transgenic rats [TGR(mREN-2)27] and by long-term treatment with the angiotensin converting enzyme inhibitor lisinopril. DESIGN AND METHODS: Three strains of rats anesthetized with urethane were used (normotensive Wistar and Sprague-Dawley rats (SDR), and [TGR(mREN-2)27]). In addition, the effects of lisinopril treatment on SDR and transgenic animals were tested. The neuronal discharge frequency and the pattern were recorded extracellularly, and their behaviors in response to angiotensin and angiotensin antagonists administered iontophoretically were analyzed. RESULTS: Angiotensin-sensitive neurons located in the ventral posteromedial and ventral posterolateral thalamic nuclei, and in the zona incerta were excited mainly by angiotensin II. The increase in the firing rates induced by administration of angiotensin II often coincided with an increase in the number of bursts of discharges. Effects induced by angiotensin II could be blocked by administration of specific antagonists (losartan, PD 123319). Long-term treatment with lisinopril reduced the neuronal responsiveness to angiotensin II in SDR significantly in comparison with that of untreated SDR controls. Lisinopril-treated SDR had a significantly lower responsiveness to angiotensin II than did hypertensive transgenic rats that had been treated with lisinopril. CONCLUSION: The results show for the first time that administration of angiotensin II induced changes in discharge rates of somatosensory neurons, and that long-term administration of lisinopril caused a significant difference between the neuronal responsiveness to angiotensin of normotensive SDR and that of hypertensive transgenic rats.

Angiotensin II↗
PubMed1997

Experimental study of laparoscopic laser-induced thermotherapy for liver tumours.

BACKGROUND: Laser-induced thermotherapy is a minimally invasive method that can be applied percutaneously or during laparotomy for the treatment of malignant liver tumours. The aim of this experimental study was to investigate whether the laparoscopic approach is suitable for laser-induced thermotherapy. Laparoscopic ultrasonography was tested as an aid to intrahepatic positioning of the applicators as well as for online monitoring during application. METHODS: A neodymium yttrium-aluminium-garnet laser was used to induce thermal lesions in the healthy liver of ten German hybrid pigs. The length of application was 840 s. Forty applications were performed with normal hepatic blood flow and 40 with hepatic blood flow interrupted by means of a laparoscopic Pringle's manoeuvre. RESULTS: A total of 20 simultaneous multifibre applications with 80 single applications were performed. Thermal necrosis with a total volume of 50.3 cm3 was induced with high precision when hepatic blood flow was interrupted temporarily. When hepatic blood flow was normal, the total volume of thermal necrosis was only 14.6 cm3 (P < 0.01). Laparoscopic ultrasonography was used successfully as an aid for exact applicator positioning and for online monitoring. Method-related complications did not occur. CONCLUSION: The laparoscopic approach is an attractive means of application for laser-induced thermotherapy and it seems that clinical testing is justified.

Animals↗
PubMed1997

Pharmacokinetics of prostaglandin E1 and its main metabolites after intracavernous injection and short-term infusion of prostaglandin E1 in patients with erectile dysfunction.

PURPOSE: Alprostadil (prostaglandin E1) is the preferred monotherapy for intracavernous injection in the diagnosis and treatment of erectile dysfunction. Our study was designed to evaluate whether there is a difference in the pharmacokinetics of prostaglandin E1 and its main metabolites after intracavernous injection or short-term intravenous infusion. In addition, we also investigated the influence of the erectile response on prostaglandin E1 kinetics after intracavernous injection. MATERIALS AND METHODS: A total of 24 patients with erectile dysfunction received, in a randomized order at an interval of 5 hours, an intracavernous injection or a 30-minute intravenous infusion of 20 microg. of alprostadil alfadex (prostaglandin E1). Venous blood samples were obtained 5 minutes before and at various times after the applications. We used highly sensitive gas chromatography/double-mass spectrometry method to measure prostaglandin E1 and its metabolites in plasma. RESULTS: We demonstrated the presence of relevant systemic blood levels of prostaglandin E1 and its metabolites immediately after intracavernous injection. We found significantly lower systemic prostaglandin E1 concentrations between 7 and 20 minutes after intracavernous injection in patients with an erectile response compared with those without. CONCLUSIONS: We found significant systemic concentrations of prostaglandin E1 and its metabolites after intracavernous injection. The systemic presence did not lead to significant changes in vital signs.

Alprostadil↗
PubMed1996

Expression of the receptor protein tyrosine kinase myk-1/htk in normal and malignant mammary epithelium.

We have recently reported the molecular characterization of a novel murine receptor PTK (myk-1), belonging to the eph-related family, whose expression was differentially regulated during mammary gland development and elevated in invasive mouse mammary tumours. In this communication we have investigated the cellular origin of myk-1 expression by in situ hybridisation and RNase protection. Murine antisense myk-1 probe specifically recognised ductal and alveolar epithelium in the resting mouse mammary gland. In normal human breast, the expression of htk, the human homologue, was also confined to the secretory luminal epithelial cells. RNase protection analysis of enriched luminal and myoepithelial cells prepared from human reduction mammoplasty tissue confirmed the luminal specificity. Elevated expression of htk was found in several human breast carcinoma cell lines as well as in primary, high grade, infiltrating, ductal carcinomas of the breast. The specific epithelial expression of the myk-1/htk receptor PTK suggest a specialised role of this eph-related PTK in the differentiation and/or maintenance of secretory epithelium in the adult.

Adult↗
PubMed1996

Coronary plaque morphology affects stent deployment: assessment by intracoronary ultrasound.

The purpose of this study was to evaluate the changes in arterial wall morphology induced by coronary stent implantation and the influence of plaque morphology on stent expansion by intravascular ultrasound. Intravascular ultrasound imaging was performed in 25 lesions before and after Palmaz-Schatz stent implantation. In the 25 lesions with ultrasound images before and after stent deployment angiographic percent diameter stenosis decreased from 71% +/- 11% to 6% +/- 14%. By ultrasound there was a gain in luminal area from 2.0 mm2 +/- 1.5 mm2 to 6.6 mm2 +/- 2.1 mm2 owing to gain in external elastic membrane area of 2.5 mm2 +/- 1.7 mm2 and reduction of plaque area of 2.1 mm2 +/- 1.7 mm2. Calcified lesions (n = 8) showed significantly less relative luminal gain (218% +/- 128% vs. 421% +/- 276%, P = .01), and stent expansion was significantly less symmetric (minimal/maximal stent diameter 0.8 +/- 0.1 vs. 0.9 +/- 0.1, P = .002) as compared to non-calcified lesions (n = 17). The difference in lumen area within the stent between the previously stenotic area and the ends of the stent was significantly larger in calcified lesions as compared to non-calcified lesions (29 +/- 28% vs. 8 +/- 23%, P = .03). Both vessel stretch and plaque reduction contribute to the luminal gain after coronary stenting. Calcified lesions interfere with optimal stent expansion.

Aged↗
PubMed1996

Effects of dopamine on neurons of the lateral geniculate nucleus: an iontophoretic study.

In urethane anesthetized rats, the iontophoretic administration of dopamine (DA) induced an inhibition of flash-evoked activity in the majority of geniculate cells investigated. Excitatory effects of DA also were found in some neurons of the dorsal lateral geniculate nucleus. The observed excitatory effects of DA were blocked selectively by D2 receptor antagonists, and the majority of inhibitory effects could be blocked by D1 receptor antagonists. In some neurons, the D2 receptor antagonist also blocked the DA-induced inhibition. Nine of 33 neurons tested responded differently to DA according to the amount ejected: with lower iontophoretic currents they increased their rates of discharge, whereas higher DA ejecting currents resulted in a suppression of their activity. Iontophoretic administration of a D1 agonist (SKF 38393) for the most part induced a decrease in baseline activity, whereas the D2 agonist (quinpirole) frequently induced an increase. These effects of agonists were dose-dependent and reproducible. Effects of the D1 and D2 agonists could be reversed by the receptor-specific dopamine antagonists. Presumed local circuit interneurons appeared to be involved in mediation of some inhibitory effects of DA, since the D2-induced inhibitions could be abolished by the GABAA antagonist, bicuculline. The majority of cells also was affected by DA antagonists given alone; these cells' responses to light usually were of an inhibitory nature. The results show that like other monoamines, DA also is involved in certain aspects of visual processing at the level of the thalamus.

Animals↗
PubMed1996

Combined effects of caffeine and alcohol during pregnancy on bones in newborn rats.

The combined effects of caffeine and alcohol on mineral contents of fetal mandibles and femurs were studied. Pregnant rats were divided into four groups: group 1, control; group 2, caffeine; group 3, alcohol; and group 4, caffeine-plus-alcohol. Alcohol (1.0 g ethanol/kg body weight) was intubated twice daily, beginning at day 9 of gestation. Caffeine (2 mg/100 g body weight) was given as a dietary supplement. Groups 1 and 2 were intubated with isocaloric sucrose solution. At birth, randomly selected pups were killed and the mandible and femur were removed and dried. Ca, P, Mg, Zn and hydroxyproline in these bones were measured. Notwithstanding the dams' intake of caffeine and alcohol administered separately, the present results suggest that the combination of caffeine and alcohol exhibited the most detrimental effects.

Animals↗
PubMed1996

Primary malignant melanoma of the oesophagus.

We report the case of a 74-year-old female patient in whom a primary malignant melanoma of the oesophagus was detected at the time of investigation of phlebothrombosis. Therapy of choice for this extremely rare tumour is radical surgical resection of the oesophagus. Even after surgical resection, primary oesophageal melanomas have a very poor prognosis. According to the present state of knowledge, it remains unclear to what extent the prognosis could be improved by adjuvant therapeutic procedures with radiotherapy or chemotherapy and immunostimulation.

Aged↗