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Biomedical subjects

G Vetter

Publications and source records attributed to G Vetter.

At least 19 recordsLinked to original sources
PubMed2005

Subcellular localization of the Triple Gene Block movement proteins of Beet necrotic yellow vein virus by electron microscopy.

The Triple Gene Block proteins TGBp1, TGBp2, and TGBp3 of Beet necrotic yellow vein virus (BNYVV) are required for efficient cell-to-cell spread of the infection. The TGB proteins can drive cell-to-cell movement of BNYVV in trans when expressed from a co-inoculated BNYVV RNA 3-based 'replicon'. TGBp2 and TGBp3 expressed from the replicon were nonfunctional in this assay if they were fused to the green fluorescent protein (GFP), but addition of a hemagglutinin (HA) tag to their C-termini did not incapacitate movement. Immunogold labeling of ultrathin sections treated with HA-specific antibodies localized TGBp2-HA and TGBp3-HA to what are probably structurally modified plasmodesmata (Pd) in infected cells. A similar subcellular localization was observed for TGBp1. Large gold-decorated membrane-rich bodies containing what appear to be short fragments of endoplasmic reticulum were observed near the cell periphery. The modified gold-decorated Pd and the membrane-rich bodies were not observed when the TGB proteins were produced individually in infections using the Tobacco mosaic virus P30 protein to drive cell-to-cell movement, indicating that these modifications are specific for TGB-mediated movement.

Beta vulgaris↗
PubMed2005

Endoscopic adrenalectomy for pheochromocytoma: difference between the transperitoneal and retroperitoneal approaches in terms of the operative course.

BACKGROUND: Due to the intraoperative catecholamine secretion with hemodynamic changes, a larger tumor size and marked neovascularization, as compared with other adrenal pathologies, endoscopic adrenalectomy for pheochromocytoma represents a particular challenge involving a more difficult and morbid procedure. The aim of this study was to identify the optimal surgical approach for endoscopic adrenalectomy in patients with pheochromocytoma. METHODS: Over a period of 10 years (February 1994 to June 2004), 38 consecutive patients underwent endoscopic adrenalectomy for pheochromocytoma. As three patients underwent a bilateral procedure, a total of 41 adrenalectomies were performed. The transperitoneal approach was carried out in 23 patients, whereas 18 patients underwent a retroperitoneal adrenalectomy by a single operative team. Perioperative parameters were prospectively followed. RESULTS: There was no conversion to the open procedure. Intraoperative hypertensive episodes occurred in 21 patients (55.3%) and were controlled by antihypertensive agents. In 11 patients (28.9%), blood pressure values rose to above 200 mmHg (> 1 min). A comparison between the retroperitoneal and transperitoneal procedures did not show a significant difference between the maximum intraoperative systolic (p = 0.730) and diastolic (p = 0.663) blood pressure values although intraoperative blood pressure peaks were seen more frequently during retroperitoneal adrenalectomy. The operative time was shorter for the patients who had transperitoneal adrenalectomy than compared to for those who had retroperitoneal adrenalectomy, although the difference was not significant. The intraoperative blood loss, perioperative morbidity, and length of postoperative hospital stay did not differ significantly between the surgical techniques (p > 0.05). CONCLUSION: After adequate preparation, endoscopic adrenalectomy may be performed in patients with pheochromocytoma via both the retroperitoneal and the transperitoneal approaches. The shorter operating time, less frequent intraoperative blood pressure peaks, and the better overview of the operating field recommend the transperitoneal approach with the patient placed in a lateral position as the preferred operative procedure.

Adrenal Gland Neoplasms↗
PubMed2004

[The choice between transperitoneal and retroperitoneal adrenalectomy. A prospective study].

INTRODUCTION: The aim of this prospective study was to evaluate the optimal surgical approach to endoscopic adrenalectomy. PATIENTS AND METHODS: Between March 1997 and February 2003, we performed 221 endoscopic adrenalectomies in 202 patients (right side 83, left side 100, bilateral 19), with an conversion rate of 2,5%. In 197 patients endoscopic adrenalectomy was carried out via retropertioneal approach 128 times and via transperitoneal approach 88 times. RESULTS: Endoscopic adrenalectomy was performed in 98% of the total number patients. No statistically significant influence ( P=0.05) was found for the parameters intraoperative blood loss, rate of postoperative complications, or duration of hospitalization in regard to the procedure. The operative time and learning curve were significantly longer with the retroperitoneal approach. Multivariate analysis identified surgical approach, tumor size (5 cm), and body mass index (25) as independent factors for operative time. CONCLUSION: The lateral transperitoneal approach is the optimal procedure for endoscopic adrenalectomy.

Adrenal Gland Neoplasms↗
PubMed2001

Determination of celecoxib in human plasma and rat microdialysis samples by liquid chromatography tandem mass spectrometry.

Methods for the determination of celecoxib in human plasma and rat microdialysis samples using liquid chromatography tandem mass spectrometry are described. Celecoxib and an internal standard were extracted from plasma by solid-phase extraction with C18 cartridges. Thereafter compounds were separated on a short narrow bore RP C18 column (30 x 2 mm). Microdialysis samples did not require extraction and were injected directly using a narrow bore RP C18 column (70 x 2 mm). The detection was by a PE Sciex API 3000 mass spectrometer equipped with a turbo ion spray interface. The compounds were detected in the negative ion mode using the mass transitions m/z 380-->316 and m/z 366-->302 for celecoxib and internal standard, respectively. The assay was validated for human plasma over a concentration range of 0.25-250 ng/ml using 0.2 ml of sample. The assay for microdialysis samples (50 microl) was validated over a concentration range of 0.5-20 ng/ml. The method was utilised to determine pharmacokinetics of celecoxib in human plasma and in rat spinal cord perfusate.

Animals↗
PubMed2001

Release of glutamate, nitric oxide and prostaglandin E2 and metabolic activity in the spinal cord of rats following peripheral nociceptive stimulation.

Peripheral tissue injury and inflammation may result in a facilitated spinal nociceptive transmission and central sensitization. Particularly, nitric oxide (NO) and prostaglandins (PGs) have been shown to be key mediators involved in the induction and maintenance of this state. By means of spinal cord microdialysis we have determined interstitial glutamate, NO (NO2-/NO3-), PGE2, glycerol, glucose and lactate concentrations in the dorsal horns of the spinal cord following peripheral nociceptive stimulation to gain further insight into the link between excitatory neurotransmitters and metabolic functions in the spinal cord during nociception. Formalin and zymosan injection into one hind paw evoked a biphasic release of glutamate and NO with the glutamate peaks preceding those of NO. Moreover, zymosan induced a biphasic increase of interstitial glycerol concentrations accompanied by an increase of interstitial lactate indicating metabolic disturbances. In contrast, formalin injection led to an elevation of dialysate glucose concentrations which may be interpreted as an indication of enhanced metabolic activity. The sequential release of glutamate and NO in the dorsal horns of the spinal cord in response to peripheral nociceptive stimulation supports the theory that NO may act as a retrograde transmitter. The metabolic changes observed after formalin and zymosan injection suggest that an intense peripheral nociceptive stimulation may not only activate but also disturb metabolic activity and possibly membrane integrity in the spinal cord.

Animals↗
PubMed2001

Phase II study of weekly 24-hour intra-arterial high-dose infusion of 5-fluorouracil and folinic acid for liver metastases from colorectal carcinomas.

BACKGROUND: A multicenter phase II trial was initiated in order to evaluate the weekly, high-dose 24-hour infusion of 5-fluorouracil (5-FU) plus folinic acid (FA) in patients with unresectable colorectal cancer hepatic metastases. PATIENTS AND METHODS: A weekly hepatic arterial infusion (HAI) of FA 500 mg/m2 followed by a 24-hour infusion of 5-FU 2,600 mg/m2 (later reduced to 2,200 mg/m2) was given via a surgically implanted intra-arterial port system. One treatment cycle consisted of six weekly applications followed by a two-week rest period. Toxicity was assessed according to the WHO criteria. Chemotherapy was continued until disease progression or complete response occurred. RESULTS: A total of 50 patients (40 chemonaive, 10 pre-treated) entered this trial. An objective tumor response occurred in 28 patients (56%), while 13 patients (26%) had stable disease. The median progression free survival was 12 months, and the median survival 22.3 months. Due to a high rate of gastrointestinal side-effects in the initial phase of the trial, the dosage of 5-FU was reduced to 2,200 mg/m2 for all subsequent patients. Diarrhea and nausea led to a dose reduction in 40% of applications and 24% of patients, respectively. One patient died of cardiac insufficiency unrelated to chemotherapy before response evaluation. CONCLUSIONS: This HAI approach using high-dose 5-FU was relatively well tolerated when 2,200 mg/m2 instead of 2,600 mg/m2 was used. The activity of this regimen is promising and warrants further evaluation and modification.

Adenocarcinoma↗
PubMed2001

Effects of selective COX-1 and -2 inhibition on formalin-evoked nociceptive behaviour and prostaglandin E(2) release in the spinal cord.

Nociception evoked prostaglandin (PG) release in the spinal cord considerably contributes to the induction of hyperalgesia and allodynia. To evaluate the relative contribution of cyclooxygenase-1 (COX-1) and COX-2 in this process we assessed the effects of the selective COX-1 inhibitor SC560 and the selective COX-2 inhibitor celecoxib on formalin-evoked nociceptive behaviour and spinal PGE(2) release. SC560 (10 and 20 mg/kg) significantly reduced the nociceptive response and completely abolished the formalin-evoked PGE(2) raise. In contrast, celecoxib (10 and 20 mg/kg) was ineffective in both regards, i.e. the flinching behaviour was largely unaltered and the formalin-induced PGE(2) raise as assessed using microdialysis was only slightly, not significantly reduced. This suggests that the formalin-evoked rapid PG release was primarily caused by COX-1 and was independent of COX-2. Mean free spinal cord concentrations of celecoxib during the formalin assay were 32.0 +/- 4.5 nM, thus considerably higher than the reported IC50 for COX-2 (3-7 nM). Therefore, the lack of efficacy of celecoxib is most likely not to be a result of poor tissue distribution. COX-2 mRNA and protein expression in the spinal cord were not affected by microdialysis alone but the mRNA rapidly increased following formalin injection and reached a maximum at 2 h. COX-2 protein was unaltered up to 4 h after formalin injection. The time course of COX-2 up-regulation suggests that the formalin-induced nociceptive response precedes COX-2 protein de novo synthesis and may therefore be unresponsive to COX-2 inhibition. Considering the results obtained with the formalin model it may be hypothesized that the efficacy of celecoxib in early injury evoked pain may be less than that of unselective NSAIDs.

Animals↗
PubMed2000

Evidence for multistability in the visual perception of pigeons.

Perceptual multistability refers to cases where perception alternates between two or more interpretations of an unchanging sensory stimulus. In a first experiment we trained eight pigeons to discriminate horizontal and vertical apparent motion stimuli and then presented a multistable display. In five cases their behavior showed alternations similar to human experiments. In a second experiment we varied the aspect ratio of the display in order to support the hypothesis of a percept-driven nature of the switching behavior. The pecking rates and mean phase durations varied as predicted. This is the first evidence of visual multistability in animals confronted with classical ambiguous figures. The data suggest a stochastic mechanism.

Adaptation, Physiological↗
PubMed2000

Improved detection and differentiation of poleroviruses infecting beet or rape by multiplex RT-PCR.

Three distinct species of virus inducing yellowing of beet, Beet mild yellowing virus (BMYV), Brassica yellows virus (BrYV, synonym BWYV) and Beet chlorosis virus (BChV) have been characterised from the genus Polerovirus. Until recently, no available tools were available to allow accurate and reliable distinction of the three species. Based on previous nucleotide sequence alignments and phylogenetic studies, we show that the use of molecular methods enabled the discrimination of these three beet Polerovirus species, but with differences in efficiency and specificity. Primers CP+ and CP- encompassing ORF-3, which encodes the coat protein, allowed the amplification by RT-PCR of a fragment of 563 bp for all isolates. Molecular methods such as SSCP or RFLP were able to discriminate these fragments by utilizing the differences in sequence. However, SSCP is a highly sensitive technique and was not suitable for the distinction of the Polerovirus species, because all isolates tested displayed a unique pattern. Analysis of the ORF3 RT-PCR products, digested with SmaI, RsaI and AccI restriction enzymes revealed four distinct patterns specific for the three species. However, point mutations can alter the RFLP patterns, making the interpretation of the results difficult. Primers were designed to amplify specifically sequences corresponding to ORF-0 of the three viral species. By using the three new sets of ORF-0 specific primers and CP+/CP- primers in a single multiplex RT-PCR, the detection and discrimination of the three beet Polerovirus species was possible in infected plants. The multiplex RT-PCR method provides a reliable and highly sensitive method to detect and identify viral species and will be of great interest for epidemiological studies of beet poleroviruses.

Brassica↗
PubMed2000

Relevance of locoregional chemotherapy in patients with liver metastases from colorectal primaries.

Progression of colorectal cancer can occur primarily isolated in the liver. But, only the minority of the affected patients is eligible for surgery. Initially, systemic chemotherapy was ineffective in the treatment of unresectable hepatic metastases. For this reason, intraarterial chemotherapy was introduced as treatment alternative to the systemic chemotherapy. Long-term intraarterial chemotherapy regimens with FUDR in patients with colorectal liver metastases, using implantable pumps and ports, resulted in improved response rates, which was confirmed by several randomized trials. However, an improvement in median survival has not yet been demonstrated after regional chemotherapy of hepatic metastases. Since the intraarterial therapy with floxuridine (FUDR) had been reported to result in a high rate of local toxicity, 5-fluorouracil (5-FU) was introduced into regional chemotherapy of the liver. A randomized trial demonstrated superiority of intraarterial 5-FU versus intraarterial FUDR therapy. Despite these reports about high response rates, the benefit of intraarterial chemotherapy remains questionable, because it has not yet resulted in a prolongation of median survival. For this reason, long-term regional chemotherapy cannot be considered as standard treatment and should therefore not be conducted outside controlled clinical trials. Further evaluations on this technique should only be performed in experienced centers.

Antimetabolites, Antineoplastic↗
PubMed2000

Inhibition of noxious stimulus-induced spinal prostaglandin E2 release by flurbiprofen enantiomers: a microdialysis study.

Peripheral noxious stimuli have been shown to induce prostaglandin (PG) E2 release at the site of inflammation and in the spinal cord. The antiinflammatory and antinociceptive effects of cyclooxygenase-inhibiting drugs are thought to depend on the inhibition of PG synthesis. R-Flurbiprofen, however, does not inhibit cyclooxygenase activity in vitro but still produces antinociceptive effects. To find out whether R-flurbiprofen acts via inhibition of spinal PG release, concentrations of PGE2 and flurbiprofen in spinal cord tissue were assessed by microdialysis. The catheter was transversally implanted through the dorsal horns of the spinal cord at level L4. R- and S-flurbiprofen (9 and 27 mg kg(-1), respectively) were administered intravenously 10-15 min before subcutaneous injection of formalin into the dorsal surface of one hindpaw. Flurbiprofen was rapidly distributed into the spinal cord with maximal concentrations after 30-45 min. Baseline PGE2 dialysate concentrations were 100.6 +/- 6.4 pg ml(-1) (mean +/- SEM). After formalin injection they rose about threefold with a maximum of 299.4 +/- 68.4 pg ml(-1) at 7.5 min. After approximately 1 h PGE2 levels returned to baseline. Both flurbiprofen enantiomers completely prevented the formalin-induced increase of spinal PGE2 release and reduced PGE2 concentrations below basal levels. S- and R-flurbiprofen at 9 mg kg(-1) produced a minimum of 15.8 +/- 5.2 and 27.7 +/- 14.9 pg ml(-1), respectively, and 27 mg kg(-1) S- and R-flurbiprofen resulted in 11.7 +/- 1.7 and 9.3 +/- 4.7 pg ml(-1), respectively. PGE2 levels remained at the minimum up to the end of the observation period at 5 h. When 27 mg kg(-1) R-flurbiprofen was injected intravenously without subsequent formalin challenge, baseline immunoreactive PGE2 concentrations were not affected. S-Flurbiprofen (27 mg kg(-1)), however, led to a moderate reduction (approximately 40%). The data suggest that antinociception produced by R-flurbiprofen is mediated at least in part by inhibition of stimulated spinal PGE2 release and support the current view that increased spinal PGE2 release significantly contributes to nociceptive processing.

Animals↗
PubMed1999

[The status of regional long-term chemotherapy in liver metastasis].

In numerous tumors, metastasis can be limited to the liver. In non-resectable patients, regional treatment modalities, especially arterial cytostatic infusion, are favored in contrast to systemic chemotherapy, whereas intraportal or intraperitoneal application is not successful. Improved results with high response rates have been reported after development of intra-arterial (i.a.) long-term regimens with FUdR in patients with colorectal liver metastases using implantable pumps and ports. However, a survival benefit could only be demonstrated in comparison with a control group only treated symptomatically. Because of several reports on major local toxicity of i.a. FUdR treatment (i.e. chemical hepatitis and biliary sclerosis) several other effective i.a. 5-FU regimens have been developed. A randomized study has demonstrated superiority of i.a. 5-FU versus i.a. FUdR. In comparison with systemic treatment, superiority has only been demonstrated in patients with an intrahepatic tumor burden of < 25%. Publications about regional treatment of patients with breast, gastric cancer or carcinoid liver metastases are rare. Despite the high response rates reported, the benefit of arterial chemotherapy remains questionable. Overall, local long-term chemotherapy cannot be recommended outside of studies as a primary treatment. However, extensive experience and new drugs support the idea of conducting further regional studies.

Antineoplastic Agents↗
PubMed1999

Relevance of neoadjuvant and adjuvant treatment for patients with resectable liver metastases of colorectal carcinoma.

BACKGROUND: Excellent results after resection of colorectal liver metastases are associated with a high rate of recurrence. Influenced by positive results of palliative and adjuvant treatment in advanced cancer, various chemotherapy regimens were evaluated to improve long-term results. METHODS: The databases Medline and Cancerlit (1982-1998) gave information about 675 patients who were treated either by means of systemic, intra-arterial, intraportal or intraperitoneal administration before or after liver resection. RESULTS: In general, the feasibility of an adjuvant treatment was tested. Proof has been furnished for the practicability of systemic and arterial therapy and for immunotherapy after liver resection whereas, for peritoneal and portal treatment, further studies are necessary. In a few non-randomised trials, it has been possible to discern a trend towards an improvement due to adjuvant postoperative therapy using historical or matched-pair control groups. Until now, only one of five randomised studies has been published. Six months of postoperative adjuvant intra-arterial treatment using 5-fluorouracil (1000 mg/m(2) for 5 days every 28 days) and folinic acid (200 mg/m(2) for 5 days every 28 days) was compared with observation only. Neither in the intention-to-treat nor in the as-treated analysis was median survival time (34.5 months versus 40. 8 months and 39.7 months versus 44.8 months, respectively) significantly increased. As neoadjuvant treatment was successful in primary non-resectable patients, this approach is now being tested in resectable patients. CONCLUSION: Despite several theoretical reasons for post- or preoperative treatment in resectable patients, every approach should be tested using of controlled studies.

Antineoplastic Agents↗
PubMed1999

The role of elastoviscosity in the efficacy of viscosupplementation for osteoarthritis of the knee: a comparison of hylan G-F 20 and a lower-molecular-weight hyaluronan.

The objective of this 12-week, double-masked, randomized, multicenter study was to compare the elastoviscous properties of a high-molecular-weight viscosupplement, hylan G-F 20 (polymer concentration, 0.8%), with those of a lower-molecular-weight hyaluronan (LMW HA) product (polymer concentration, 1%) and to determine the relationship of elastoviscosity to efficacy in the treatment of patients with osteoarthritis (OA) of the knee. Patients had radiographically confirmed primary idiopathic OA of the knee (Larsen grades I to V) with pain despite other treatments. After a 2-week washout period, 70 patients (73 knees) received three 2-mL intra-articular injections of test solution at 1-week intervals. Thirty-eight patients (38 knees) received hylan G-F 20, and 32 patients (35 knees) received LMW HA. During the 12-week follow-up period, the primary outcome measures assessed by patients (using a visual analogue scale) were weight-bearing pain, most painful knee movement, and overall treatment response; the primary outcome measures assessed by study evaluators were weight-bearing pain and overall assessment of treatment. The dynamic elastoviscous properties of the test solutions were measured on an oscillating Couette-type rheometer. Hylan G-F 20 was more elastoviscous than the LMW HA at all frequencies measured (0.001 to 10 Hz). At the final evaluation, patients who received hylan G-F 20 had significantly better results on all primary outcome measures compared with those who received LMW HA. No systemic adverse events were reported. Local adverse events consisted of pain or swelling, noted in 2 of 38 knees injected with hylan G-F 20, and pain, noted in 1 of 35 knees injected with LMW HA (adverse event rates per injection, 1.8% and 0.9%, respectively). The difference in the incidence of adverse events between groups was not statistically significant. The higher-molecular-weight, more elastoviscous hylan G-F 20 had significantly greater pain-relieving effects than did the lower-molecular-weight, less elastoviscous hyaluronan.

Adult↗
PubMed1999

[Conditions for medical disability according to section 125 SGB III].

The section 125 of the German Social Statute Book No. III (unemployment insurance) determines the conditions for an unemployed insured person who is unable to work due to a disease. Ascertainment of the existence of the medical conditions governed by section 125 is not only a task for the physicians of the unemployment insurance, it is also a task for the doctors of the pension insurance and of the health insurance. Hence it is very important that all medical experts of social insurances are in consensus in view of these medical requirements. In this paper the medical conditions for section 125 are described: The disease must be so serious that the unemployed insured person will be unable to return to work within the next six months. The inability to work will be continuous. In this case the unemployment insurance continues to pay unemployment benefit in spite of the inability to work until the pension insurance body agrees to pay a pension.

Disability Evaluation↗
PubMed1987

Double-blind comparative clinical trial with S-adenosylmethionine and indomethacin in the treatment of osteoarthritis.

In a randomized double-blind study, 36 patients with osteoarthritis of the knee, hip, and/or spine were treated orally with a daily dose of S-adenosylmethionine (SAMe)(1,200 mg) or indomethacin (150 mg) over a period of four weeks. Pretreatment and posttreatment clinical parameters were determined and assessed according to a standard scoring system. SAMe therapy significantly improved the total score obtained by the sum of all clinical findings, as compared with pretreatment values. Similar improvement was evident in indomethacin-treated subjects. Two patients in the SAMe group reported slight nausea after two weeks of therapy, whereas adverse effects developed in seven patients in the indomethacin group.

Aged↗