Biomedical subjects

D Albrecht

Publications and source records attributed to D Albrecht.

At least 73 records · Page 4Linked to original sources

PubMed1996

[The fully implantable minimally invasive hepatic artery catheter for locoregional chemotherapy of nonresectable liver metastases in defective conventional implanted therapy catheters].

Dysfunction of arterial access devices used in association with intra-arterial chemotherapy for the treatment of unresectable liver metastases usually requires stopping the therapy or relaporotomy and reimplantation of a new arterial catheter. In this article our initial experience of a new technique, the so-called MIAH catheter (minimally invasive hepatic artery catheter) in 36 patients (age 37-78 years) are reported. The MIAH catheter was percutaneously inserted into the subclavian artery under sonographic guidance and advanced via the descending aorta selectively into the hepatic artery. Finally it was connected to a totally implantable pump. There were no deaths related to the operation. Operative or early complications occurred in 5 cases (13.8%); late complications were seen in 13 patients (36.1%). Nevertheless continuation of intra arterial chemotherapy was possible in all cases. In cases of dysfunction of conventional arterial access devices the MIAH catheter makes it possible to continue intra-arterial chemotherapy without requiring laporotomy.

Adult↗

PubMed1996

Alloplastic replacement of the urinary bladder.

PURPOSE: The loss of a functioning bladder is nowadays mostly managed by replacement with gastrointestinal segments. Management of these urinary diversions is difficult and the long-term effects are unknown. We developed a silicone rubber prosthesis for alloplastic replacement of the urinary bladder and tested it in an animal experiment. MATERIAL AND METHODS: Two artificial bladders were implanted into subcutaneous pockets on each side of the anterior abdominal wall. Cystectomy was performed and each prosthesis was connected to one kidney. Distally, a Y-shaped tube sutured to the urethral stump joined the two bladder outlets. The whole system was successfully implanted in 5 sheep with a mean follow-up of 11.5 months (5-19 months). RESULTS: Adequate capacity, effective and reliable mechanical function and patent anastomoses to the renal pelvis and the urethra could be achieved. Blood chemistry and renal ultrasound were performed at regular intervals demonstrating neither morphological nor functional deterioration of the renal parenchyma. Histopathological examination in the end of the experiment confirmed the excellent clinical results. CONCLUSIONS: The positive outcome of these animal experiments suggests this system would be useful for human bladder substitution. Standardized industrial production of the prostheses will be needed prior to implantation in humans.

Animals↗

PubMed1996

[Laser-induced thermotherapy for palliative treatment of malignant liver tumors: results of 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 malignant liver tumors. Local control of tumor growth was obtainable in completely hyperthermic tumors. Due to the small and inhomogeneous patient population (n = 20), an assessment of the method regarding prognostic gain for the patient is not possible in such a short follow-up period.

Aged↗

PubMed1995

Cholecystokinin excites neostriatal neurons in rats via CCKA or CCKB receptors.

The effect of iontophoretically applied cholecystokinin (CCK) on neurons of the neostriatum was studied in rats anaesthetized with urethane. The most frequently observed effect of the sulphated octapeptide (CCK-8S) on striatal neurons was excitation. Spontaneously active neurons responded more often to CCK-8S than quiescent cells. Silent, primarily non-responsive neurons could often be stimulated with CCK-8S using glutamate to induce an ongoing discharge. Thus, 45.8% of the 177 neurons studied changed their discharge rate by more than 30%. Certain CCK receptor antagonists could prevent the effect of CCK-8S, fully or at least partly, in the majority of CCK-responsive neurons. The data suggest that cholecystokinin modulates the firing of active neostriatal neurons via the CCKA or the CCKB receptor type. Furthermore, we compared neuronal responses to glutamate with those recorded during concomitant administration of CCK-8S in order to study the interaction of both transmitters, which may be colocalized in striatal afferents. CCK-8S mainly enhanced the excitatory effect of glutamate on striatal neurons, but in several neurons the response to glutamate was reduced. The CCKB receptor antagonist could prevent CCK-8S from increasing the glutamate-induced activation.

Animals↗

PubMed1995

Inhibitory effects of cholecystokinin on rat's geniculate activity can be blocked by GABA-antagonists.

Cholecystokinin applied iontophoretically as the sulfated octapeptide (CCK-8S) or as highly selective CCKA- and CCKB-agonists induced excitatory as well as inhibitory effects on dorsal lateral geniculate unit activity. Inhibitory effects of CCK could be abolished by administration of GABAergic antagonists, especially bicuculline. Therefore, interneurons seem to be largely excited by CCK, and in this way, they appear to mediate the inhibition of the discharge rate in geniculate relay cells induced by CCK.

Animals↗

PubMed1995

Properties of low Mg2+ induced epileptiform activity in rat hippocampal and entorhinal cortex slices during adolescence.

Properties of low Mg2+ induced epileptiform activity were studied in isolated rat hippocampal slices or in combined slices containing the entorhinal cortex and hippocampus. Slices were prepared from rats which were 1, 2, 3 or more weeks of age. Field potentials and often also changes in [K+]0, [Ca2+]0 and [Mg2+]0 were recorded with appropriate ion selective microelectrodes. In isolated hippocampal and entorhinal cortex/hippocampal combined slices the latency to onset of epileptiform activity upon lowering of extracellular Mg2+ was shortest in the youngest age group and approached adult levels at about the fourth postnatal week. Washout kinetics of Mg2+ were fastest in slices from 1-week-old rats. The onset of low Mg2+ induced epileptiform activity occurred at higher Mg2+ levels in slices from young compared with those from adult animals. In isolated hippocampal slices the epileptiform discharges varied in appearance during development. Short discharges lasting for 40 to 80 ms were observed in hippocampal slices prepared from 1-week-old and adult animals. Seizure-like events (SLE's) characterized by slow negative potential shifts and characteristic elevations in [K +]0 and decreases in [Ca2+]0 lasting for up to 30 s were observed in a proportion of hippocampal slices prepared after the first, second and third postnatal week. In slices from week 2 and 3 seizure-like events often progressed into spreading depressions (SD's). In entorhinal cortex/hippocampal combined slices seizure-like events were observed in all age groups. The seizure-like events spread readily into dentate gyrus (DG), area CA3 and CA1 after week 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1995

iyk, a novel intracellular protein tyrosine kinase differentially expressed in the mouse mammary gland and intestine.

Using a polymerase chain reaction based cloning strategy and conventional cDNA library screening we have characterized a novel intracellular protein tyrosine kinase from mouse mammary tissue. The gene encodes a protein with structural characteristics reminiscent of the src family of protein tyrosine kinases, a partial myristylation signal with glycine in position +2, SH3 and SH2 domains followed by a C-terminal tyrosine kinase domain. Interestingly, a potential bipartite nuclear localizing signal is located within the SH2 domain. A data base search revealed the highest homology to the human frk/rak gene. Northern blot analysis of mammary gland development indicated preferential epithelial expression in resting mammary glands and up-regulation in mammary tumours. Expression in organs was highest in the intestinal tract and was confined to the small intestine. We have named this gene iyk, (intestine tyrosine kinase), reflecting its pattern of expression.

Amino Acid Sequence↗

PubMed1995

Cholecystokinin affects the neuronal discharge mode in the rat lateral geniculate body.

Neurons of the dorsal lateral geniculate body (dLGB) discharge either continuously with single spikes or in bursts, that is, groups of action potentials with an interspike interval < or = 4 ms. The influence of the sulphated octapeptide of cholecystokinin (CCK-8S) on the discharge mode of dLGB neurons was studied in rats anesthetized with urethane. Unit activity was recorded during repeated stimulation with diffuse light. The occurrence of bursts was determined during control conditions and during iontophoretic administration of CCK-8S and its antagonists. CCK-8S frequently increased the number of bursts. The percentage of spikes involved in bursts was mainly augmented in neurons that responded after short latency to light or were excited by light-off. It was predominantly reduced in units responding to light after long latency with a primary excitation. CCKA receptors seem to contribute to burst induction, since CCK-8S reduced bursting in the presence of the CCKA receptor antagonist Ge 410 and increased bursting when applied with the CCKB receptor antagonist PD 135,158. These bursts were frequently related to light stimuli.

Amino Acid Sequence↗

PubMed1995

[Occupational rehabilitation after percutaneous transluminal coronary angioplasty (PTCA)--correlation with subjective and objective parameters].

On the basis of medical criteria percutaneous transluminal coronary angioplasty (PTCA) is followed by only a short interval of work inability. This study evaluated the interval between PTCA and the return to work and the factors which may influence this interval. The study included 122 working patients with angiographically successful PTCA. Patients were followed up clinically and angiographically and completed a standardized questionnaire directly after PTCA and 4 months later. The study population comprised 87 patients (81 men, 6 women) who filled out both questionnaires appropriate for evaluation. Of these 48 (55%) had single-vessel, 27 (31%) two-vessel, and 12 (14%) three-vessel disease. Complete revascularization in terms of treatment of all lesions above 70% was achieved in 85 (98%) patients. In 30 (34%) patients restenosis developed during the observation period as evaluated by coronary angiography. At the time of the second evaluation 46 (53%) patients complained of persisting or new thoracic pain, which they understood as cardiac pain. After 4 months 68 (78%) patients returned to work, 12 (14%) were on sick leave, 3 (3%) were unemployed, and 4 (5%) were retired. The median of time on sick leave after PTCA was 14 days. The length of sick leave after PTCA was found to depend significantly on the previous intention to retire (25% vs. 75%, p < 0.01). Patients who did not return to work during study period reported more frequently of thoracic pain (55% vs. 45%, p = 0.01) and had less intention to return to work after PTCA (6% vs. 94%, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Psychological↗

PubMed1994

3' end processing of mouse histone pre-mRNA: evidence for additional base-pairing between U7 snRNA and pre-mRNA.

We have analysed the extent of base-pairing interactions between spacer sequences of histone pre-mRNA and U7 snRNA present in the trans-acting U7 snRNP and their importance for histone RNA 3' end processing in vitro. For the efficiently processed mouse H4-12 gene, a computer analysis revealed that additional base pairs could be formed with U7 RNA outside of the previously recognised spacer element (stem II). One complementarity (stem III) is located more 3' and involves nucleotides from the very 5' end of U7 RNA. The other, more 5' located complementarity (stem I) involves nucleotides of the Sm binding site of U7 RNA, a part known to interact with snRNP structural proteins. These potential stem structures are separated from each other by short internal loops of unpaired nucleotides. Mutational analyses of the pre-mRNA indicate that stems II and III are equally important for interaction with the U7 snRNP and for processing, whereas mutations in stem I have moderate effects on processing efficiency, but do not impair complex formation with the U7 snRNP. Thus nucleotides near the processing site may be important for processing, but do not contribute to the assembly of an active complex by forming a stem I structure. The importance of stem III was confirmed by the ability of a complementary mutation in U7 RNA to suppress a stem III mutation in a complementation assay using Xenopus laevis oocytes. The main role of the factor(s) binding to the upstream hairpin loop is to stabilise the U7-pre-mRNA complex. This was shown by either stabilising (by mutation) or destabilising (by increased temperature) the U7-pre-mRNA base-pairing under conditions where hairpin factor binding was either allowed or prevented (by mutation or competition). The hairpin dependence of processing was found to be inversely related to the strength of the U7-pre-mRNA interaction.

Animals↗

PubMed1994

Very slow oscillations of activity in geniculate neurones of urethane-anaesthetized rats.

The spontaneous activity of neurones of the dorsal lateral geniculate nucleus (dLGN) in urethane-anaesthetized rats was examined for the presence of very slow oscillatory activity. Fifty-four of the 86 dLGN neurones (63%) recorded extracellularly displayed oscillatory activity in the 0.02-0.03 Hz range. Similar very slow oscillations were observed in the ventral part of the LGN and the nucleus lateralis posterior (LP), but not in the hippocampus. Diffuse light stimuli dampened or blocked these oscillations in 23 of the 29 neurones tested. In a second group of experiments (iontophoretic studies) the very slow oscillatory activity was efficiently blocked by N-methyl-D-aspartate.

Action Potentials↗

PubMed1994

Developmental changes in the number, size, and orientation of GFAP-positive cells in the CA1 region of rat hippocampus.

Changes in extracellular potassium concentration as measured with ion-selective microelectrodes revealed abnormally large accumulations in the hippocampus during postnatal development. While rises in [K+]o during stimulation of the Schaffer collaterals were limited to about 12 mM in adult animals, identical stimulations elicited rises to levels as large as 18 mM in juveniles. Since astrocytes are believed to play an important role in K+ homeostasis, we studied the postnatal development of astrocytes in the CA1 region of rat hippocampus in four age groups using a polyclonal antibody against glial fibrillary acidic protein (GFAP). The main proliferation of GFAP-positive cells (GFAPpc) occurred in all laminae between postnatal days 8 and 16. The number of GFAP-positive astrocytes per unit area was reached in stratum lacunosum-moleculare and stratum oriens at about 2 weeks and in stratum radiatum at about 3 weeks of age. During further development--at the age of 24 days--the orientation of individual astrocytes in stratum radiatum became polar with an orientation almost perpendicular to stratum pyramidale. This was revealed by an analysis based on determination of the quotients between the angular orientation of the processes of single individual GFAP-positive cells. When the crossing points of all glial processes over vertical and horizontal grid lines were determined and respective quotients evaluated, the same development towards a perpendicular orientation of astrocytes was noted in stratum radiatum. The same approach revealed a transient orientation parallel to the fissure in stratum lacunosum-moleculare around day 24. Camera lucida drawings of GFAPpc in stratum radiatum revealed that astrocytes became larger during the first three postnatal weeks, followed by a reduction of various parameters (e.g., cell extension, branching pattern) until adulthood. The observed developmental changes of astroglial cells may contribute to the known delayed maturation of potassium regulation in rat hippocampus.

Aging↗

PubMed1994

Cholecystokinin-induced activity changes of dorsal lateral geniculate neurons in rats.

The effects of iontophoretically applied cholecystokinin fragments and cholecystokinin antagonists on neurons of the dorsal lateral geniculate nucleus were investigated with extracellular recordings in rats anesthetized with urethane. The peptide cholecystokinin-8S, which has affinity for both cholecystokinin-A and -B receptors, altered the baseline firing as well as the responses to visual stimuli of about one half of the investigated neurons (90 out of 190). Excitatory effects predominated (P < 0.01, Wilcoxon test), although inhibitory effects were also observed. The effects of cholecystokinin-8S were dose-dependent. Neurons sensitive to cholecystokinin-8S could be found in all regions of the dorsal lateral geniculate nucleus, but they differed in their susceptibility to cholecystokinin in relation to their location. The B-agonist, BOC-cholecystokinin-4, also changed the baseline firing as well as the light-evoked activity of dorsal lateral geniculate nucleus neurons. The effects were either excitatory or inhibitory. Changes induced by cholecystokinin-8S could be effectively blocked by the cholecystokinin-B antagonist, CAM 1028 (19 out of 22 cholecystokinin-sensitive neurons tested). The cholecystokinin-A antagonist, Ge 410, blocked cholecystokinin-induced effects in 10 out of 16 neurons. These results indicate that the modulation of geniculate cell firing by cholecystokinin is mediated by both A-and B-receptor types.

Animals↗

PubMed1994

[Case report of extra-intestinal manifestation of salmonella infection].

The case history of a 75 year old man is demonstrated, who developed an abscess in the scar after B-II-resection 30 years ago. In this abscess S. typhi murium was detected. Diabetes mellitus was an additional risk factor. A review of the literature is given concerning extraintestinal manifestations of salmonellosis with emphasis to the predisposing conditions.

Abdominal Abscess↗

PubMed1994

Expression of two novel eph-related receptor protein tyrosine kinases in mammary gland development and carcinogenesis.

To investigate the involvement of protein tyrosine kinases (PTKs) in the growth control of mammary epithelial cells, we have used PCR based cloning to identify PTKs expressed in a mouse mammary epithelial cell line. This approach led to the isolation of two receptor PTKs of the eph-related subfamily; myk-1, a novel member expressed predominantly in lung, heart and mammary gland and myk-2, a close relative of the human eck gene. Northern blot analysis of RNA from mouse mammary glands at different stages of development revealed that myk-1 and myk-2 expression is induced at puberty and differentially regulated during the estrus cycle. myk-1 and myk-2 expression was down-regulated during the pregnancy induced differentiation of the mammary gland. Over-expression of myk-1 and myk-2 was found in the undifferentiated and invasive mammary tumors of transgenic mice expressing the Ha-ras oncogene. In contrast, no elevated expression of either gene could be detected in the well differentiated and non-metastatic mammary tumors of c-myc expressing transgenic mice. These results indicate that myk-1 and myk-2 expression is induced during the proliferation of the mammary gland and down-regulated by its differentiation.

3T3 Cells↗

PubMed1994

[Follow-up and characteristics of restenoses after coronary stent implantation in asymptomatic patients and patients with few symptoms].

Following coronary Palmaz-Schatz single stent implantation 50 patients had an angiographic follow-up after 4-6 and after 12 months. Quantitative angiography revealed that the restenosis process has finished 4-6 months after stent implantation in the majority of patients. In the present study, 6% had, however, developed symptomatic restenosis at 1-year follow-up. Detailed assessment of 15 patients revealed that the residual stenosis after stent implantation is most prominent at the stent edges, however, restenosis did occur in all segments in about the same amount. Analysis of several clinical and morphologic variables did not reveal any particular risk factor for the development of restenosis. The results of the present study do suggest that follow-up angiography should be performed 4-6 months after stent placement.

Adult↗

PubMed1994

[Transperitoneal technique of preperitoneal mesh implantation in laparoscopic hernioplasty of direct and indirect inguinal hernias].

The method of transperitoneal application of a large polypropylene-mesh in the preperitoneal space for laparoscopic inguinal hernia repair is described. The own experiences with a total number of 64 inguinal hernias are presented. The technique takes the principle of conventional hernia repair into account and appears to be a safe and effective way to repair indirect and direct inguinal uni- or bilateral hernias. During a mean follow-up of 24 weeks one recurrence occurred resulting from an inadequate application of the mesh. The technique presented is effective for laparoscopic inguinal hernia repair with low morbidity. Long-term follow-up is needed to determine late recurrence rate.

Adult↗

PubMed1993

Functional health status in male patients without restenosis following successful PTCA.

In a prospective pilot study, subjective and objective parameters of the health status were assessed in 148 male patients (mean age 56 +/- 8.4 years) before and 4 months after successful coronary angioplasty (PTCA). Restenosis was defined as residual diameter stenosis > 50%. Although 96 patients (65%) had not developed restenosis at 4 months' invasive follow-up, subjective assessment of general well-being was unchanged in 26% or worse in 71%; overall anginal status and exercise performance had however improved. Of 71 men younger than 60 years who had no restenosis at follow-up, 4 men retired and 13 remained on medical leave. The striking disparity between subjective and objective parameters was not related to significant differences of age, exercise capacity, and left ventricular ejection fraction, as well as to baseline characteristics (previous myocardial infarction, extent of coronary heart disease, comorbidity) compared with 52 patients with restenosis. Thus, despite documented sustained success after PTCA, the majority of patients failed to resume the status of subjective well-being.

Adult↗