Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Crystallization of the dimerization-initiation site of genomic HIV-1 RNA: preliminary crystallographic results (1999)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 55 (1999), S. 281-284 
    Details
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The genomic RNA of all retroviruses is encapsidated in virions as a dimer of single-stranded chains held together near their 5′-end. For HIV-1, the initial site of dimerization has been shown to be a hairpin with a nine-residue loop containing a self-complementary sequence of six residues. This structure is proposed to promote dimerization by loop–loop interaction and formation of a so-called `kissing complex'. A 23-nucleotide RNA strand containing the loop enclosed by a seven base-pair stem has been synthesized. This oligomer was crystallized by the vapour-diffusion method at 310 K, pH 6.5, with methyl-pentanediol as the precipitant agent in the presence of MgCl2, KCl and spermine. Quasi-complete diffraction data were obtained at 2.7 Å resolution with a conventional X-ray source and at 2.3 Å resolution on a synchrotron beamline. The space group is P3121 or its enantiomorph P3221, with cell parameters a = b = 60.1, c = 65.9 Å at ambient temperature, or a = b = 59.0, c = 64.3 Å in a nitrogen-gas stream. There are two oligomers per asymmetric unit as determined from absorbance measurements of a dissolved crystal whose volume was carefully determined. In some cases, either perfectly or partially twinned crystals were obtained. Perfect twinning is detected by an apparent hexagonal symmetry and yields unusable crystallographic data, whilst partial twinning yields usable data after adequate processing. Structure solution is under way by searching for heavy-atom derivatives and systematically substituting bromo- or iodo-uridines for uridines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0907444998008506
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Laparoscopic splenectomy and nephrectomy in a rat model (1997)
    Springer
    Surgical endoscopy and other interventional techniques 11 (1997), S. 491 -494 
    Details
    ISSN: 1432-2218
    Keywords: Key words: Laparoscopy — Rat — Model — Splenectomy — Nephrectomy — Tumor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: In experimental studies on the effects of laparoscopic procedures on tumor biology, a localized tumor model is desirable. The spleen and the kidney are preferable, because these organs are amenable to tumor placement and subsequent removal. This study describes the technique of laparoscopic splenectomy and nephrectomy in the rat model. Methods: Pneumoperitoneum was established by CO2 insufflation. Laparoscopic splenectomy involved two-handed dissection, intracorporeal ligation, and division of gastrosplenic attachments and hilar and short gastric vessels. Laparoscopic nephrectomy was done by intracorporeal ligation and division of the renal vessels and the ureter after mobilization of the kidney. Results: Laparoscopic splenectomy was performed in six rats; laparoscopic nephrectomy was done in six rats. Operative time ranged from 45 to 90 min for splenectomy and from 40 to 65 min for nephrectomy. Postoperatively, two rats died from hemorrhage. Necropsy of the rats after 10 days revealed adhesion in three rats after splenectomy and in four rats after nephrectomy. Inflammatory processes were found around the silk ligatures in all rats after splenectomy; in two rats wound infections occurred at the port sites. Conclusions: Laparoscopic splenectomy and nephrectomy in the rat proved technically feasible and may provide new localized tumor models suitable to be used in further studies on the oncological effects of laparoscopic surgery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004649900400
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Laparoscopic vs conventional bowel resection in the rat (1998)
    Springer
    Surgical endoscopy and other interventional techniques 12 (1998), S. 412-415 
    Details
    ISSN: 1432-2218
    Keywords: Key words: Insulin-like growth factor — Laparoscopy — Bowel — Cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: The role of laparoscopic surgery in the treatment of colorectal disease is still controversial. To assess the metabolic consequences of laparoscopic and open bowel surgery, we studied serum levels of insulin-like growth factor 1 (IGF-1), an anabolic and mitogeneic peptide, in rats. Materials and methods: In experiment 1, the serum IGF-1 levels of 10 rats undergoing laparoscopic small bowel resections (group I) and 10 rats undergoing conventional small bowel resections (group II) were determined before surgery and on days 1, 2, and 7. Experiment 2 compared five rats that had CO2 pneumoperitoneum (group III), five rats that underwent laparotomy (group IV), and five rats that received anesthesia only (group V). Differences in IGF-1 levels were tested with analysis of covariance. Results: In experiment 1, preoperative IGF-1 levels were similar in groups I and II (87.9 ± 6.1 nmol/L versus 90.5 ± 8.1 nmol/L). One day after surgery IGF-1 was 54.6 ± 10.5 in group I versus 41.6 ± 8.3 in group II (p= 0.006). Two days after surgery, IGF-1 was 79.4 ± 9.2 in group I versus 59.0 ± 10.5 in group II (p 〈 0.001). Seven days after both types of surgery, IGF-1 levels had returned to almost normal levels. In experiment 2, no significant differences were found between the rats with CO2 pneumoperitoneum (group III) and those with laparotomy only (group IV). Rats that had anaesthesia only showed a significant decrease in IGF-1 levels between days 0 and 1 (p 〈 0.018). Conclusion: Our study indicates that laparoscopic bowel surgery is associated with a better postoperative anabolic state (i.e., less catabolism) than conventional surgery. This finding reflects a potential benefit of laparoscopy in bowel surgery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004649900693
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Cyclosporin A enhances locoregional metastasis of the CC531 rat colon tumour (1997)
    Springer
    Journal of cancer research and clinical oncology 123 (1997), S. 21-24 
    Details
    ISSN: 1432-1335
    Keywords: Cyclosporin A ; Growth promotion ; Metastasis ; Multidrug resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The immunosuppressive drug cyclosporin A has been evaluated recently in phase II trials in cancer therapy as a reverter of P-glycoprotein-mediated multidrug resistance. As an immunosuppressive agent, cyclosporin A potentially can enhance tumour growth. We investigated this potency of cyclosporin A in the weakly immunogenic CC531 colon adenocarcinoma model, using the same dose that had previously been shown to intensify the antitumour activity of doxorubicin in vivo. In vitro cyclosporin A caused no growth acceleration and only in high doses was growth inhibition of CC531 cells observed. In vivo no evidence of growth enhancement was found in short-term assays but, after 4 weeks, rats treated with cyclosporin A had a significantly higher tumour load, mainly consisting of locoregional metastases. These experiments in the CC531 tumour model show that cyclosporin A, used as a reverter of multidrug resistance, may produce short-term improvement of antitumour activity but may also induce enhancement of tumour metastasis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01212610
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Hepatocellular carcinoma and liver transplantation: an animal model (1998)
    Springer
    Transplant international 11 (1998), S. S201 
    Details
    ISSN: 1432-2277
    Keywords: Key words Hepatocellular carcinoma ; Liver transplantation ; Rat model ; DEN
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The objective of this study was to develop an animal model to evaluate the biology of hepatocellular carcinoma (HCC) recurrence after liver transplantation. HCC was induced in Brown Norway (BN) rats (n = 45) by diethylnitrosamine (DEN) administered continuously through the drinking water. Starting from day 14, rats were sequentially autopsied or syngeneically transplanted according to Kamada's cuff technique. After 74 days of DEN administration, neoplastic liver lesions appeared and after a mean of 102 days (SD ± 6) the animals died of abdominal haemorrhage from liver tumours. At this time lung metastases were present in three-fifths animals. Transplantation success was dependent on the DEN consumption and thereby the tumour stadium. After 74 days of DEN administration BN rats could no longer be transplanted because of anaesthetic problems or technical problems due to tumour adhesion to surrounding tissues. No recurrence was found in the transplants. In conclusion, we believe that timing of the operation in this HCC model is essential because the physical condition of the animals prohibits orthotopic liver transplantation in an advanced tumour stage. With a different DEN dosage scheme this problem may be solved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001470050461
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Port-site metastases (1998)
    Springer
    Surgical endoscopy and other interventional techniques 12 (1998), S. 1377-1380 
    Details
    ISSN: 1432-2218
    Keywords: Key words: Port site — Metastasis — Laparoscopy — Cancer — Chimney — Trauma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Port-site metastases after laparoscopic procedures in patients with digestive malignancies have evoked concern. The pathogenesis of port-site metastases remains unclear. Two experiments in rats were performed to determine the impact of both tissue trauma and leakage of CO2 along trocars (chimney effect) in the development of port-site metastases. Methods: Experiment I: Ten WAG rats had four 5-mm incisions in all abdominal quadrants. The incisions on the right side were crushed to induce tissue trauma. After inserting 5-mm trocars in all incisions, a pneumoperitoneum was created, and CC-531 tumor cells were injected intraperitoneally. CO2 was insufflated for 20 min. Experiment II: Ten WAG rats had 5-mm incisions in the left and right abdominal upper quadrant. A 5-mm trocar was inserted in the incision in the left upper quadrant, and a 2-mm trocar was inserted in the incision in the right upper quadrant. After insufflating the abdomen, CC-531 tumor cells were injected intraperitoneally. Total leakage of CO2 along the trocar in the right quadrant was 10 liters. After 4 weeks, in both experiments, the tumor deposits at the trocar sites were assessed. Statistical analysis was performed by the Wilcoxon matched-pairs test. Results: Experiment I: The median weight of tumor deposits at the trocar sites without induced tissue trauma was 22 mg. At the traumatic port sites, median weight of tumor deposits was 316 mg (p= 0.007). Experiment II: The median weight of tumor deposits at the leaking trocar sites was 478 mg and at the control sites 153 mg (p= 0.009). Conclusion: Tissue trauma at trocar sites and leakage of CO2 along a trocar appear to promote implantation and growth of tumor cells at port sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004649900862
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Laparoscopic surgery in the rat (1996)
    Springer
    Surgical endoscopy and other interventional techniques 10 (1996), S. 490-494 
    Details
    ISSN: 1432-2218
    Keywords: Key words: Laparoscopy — Rat — Tumor take — Weight loss — Pneumoperitoneum — Bowel resection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: The ability of laparoscopic techniques to treat malignant disease is controversial. We developed a rat model to assess metabolic and oncological effects of laparoscopic surgery. Methods: Experiment I. The postoperative body weight in 10 rats having laparoscopic bowel resection (group I), 10 rats having open bowel resection (group II) and 5 rats having anesthesia only (group III) was determined. Experiment II. Tumor take was scored in 11 rats having laparoscopic bowel resection (group IV), 11 rats having open bowel resection (group V), 6 rats having CO2 pneumoperitoneum without bowel resection (group VI) and 6 rats having anesthesia only (group VII). All rats had CC531 cancer cells injected intraperitoneally postoperatively. Results: Experiment I. Body weight loss in group I compared to group II (p〈0.036). Rats of group III lost no weight postoperatively. Experiment II. Tumor take was less in the subcutis (p=0.005), parietal peritoenum (p〈0.001) and bowel anastomosis (p=0.021) in group IV compared to group V. Tumor take was significantly greater at all sites except for subcutis in group VI compared to VII (all p〈0.022). Conclusions: Laparoscopic surgery is associated with less postoperative weight loss and less tumor take compared to open surgery. CO2 insufflation appears to increase tumor take.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004649910096
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Laparoscopic surgery in the rat (1996)
    Springer
    Surgical endoscopy and other interventional techniques 10 (1996), S. 490-494 
    Details
    ISSN: 1432-2218
    Keywords: Laparoscopy ; Rat ; Tumor take ; Weight loss ; Pneumoperitoneum ; Bowel resection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: The ability of laparoscopic techniques to treat malignant disease is controversial. We developed a rat model to assess metabolic and oncological effects of laparoscopic surgery. Methods: Experiment I. The postoperative body weight in 10 rats having laparoscopic bowel resection (group I), 10 rats having open bowel resection (group II) and 5 rats having anesthesia only (group III) was determined. Experiment II. Tumor take was scored in 11 rats having laparoscopic bowel resection (group IV), 11 rats having open bowel resection (group V), 6 rats having CO2 pneumoperitoneum without bowel resection (group VI) and 6 rats having anesthesia only (group VII). All rats had CC531 cancer cells injected intraperitoneally postoperatively. Results: Experiment I. Body weight loss in group I compared to group II (p〈0.036). Rats of group III lost no weight postoperatively. Experiment II. Tumor take was less in the subcutis (p=0.005), parietal peritoenum (p〈0.001) and bowel anastomosis (p=0.021) in group IV compared to group V. Tumor take was significantly greater at all sites except for subcutis in group VI compared to VII (all p〈0.022). Conclusions: Laparoscopic surgery is associated with less postoperative weight loss and less tumor take compared to open surgery. CO2 insufflation appears to increase tumor take.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00188392
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...