We have examined whether dietary polyamines influence the formation and
initial growth of azoxymethane (AOM)-induced aberrant crypt foci (ACF) in
rat colon. Effects of a combination of dietary polyamines at three dose
levels (putrescine: 50, 280, 740 nmol/g; spermidine: 10, 261, 763 nmol/g;
spermine: 1, 31, 91 nmol/g) in the polyamine-poor AIN-76A diet were studied
in animals in two different experimental situations: animals treated with
AOM alone and animals treated with AOM + difluoromethylornithine (DFMO), a
specific inhibitor of endogenous polyamine synthesis. In both experimental
situations, dietary polyamines enhanced the growth of ACF, expressed as the
number of large ACF (foci with three or more aberrant crypts, ACF > or =
3), whereas the formation of ACF, expressed as the number of ACF, was
apparently not altered. In animals treated with AOM alone, maximal growth
enhancing effect on ACF was nearly obtained with the median level of
dietary polyamine. In rats fed a low polyamine diet, basic AIN-76A, DFMO
reduced the growth of AOM-induced ACF by 83%. This inhibitory effect of
DFMO was counteracted by dietary polyamines in a dose- dependent manner,
and it was abolished at the highest level of polyamines. In conclusion, it
was demonstrated that dietary polyamines are able to enhance the growth of
AOM-induced ACF. Further, dietary polyamines reversed the DFMO-caused
inhibition of ACF growth, probably by compensating for the DFMO-reduced
endogenous polyamine synthesis.
相似文献
The Authors for the Live Organ Donor Consensus Group
JAMA. 2000;284:2919-2926.
Objective To recommend practice guidelines for transplantphysicians, primary care providers, health care planners, andall those who are concerned about the well-being of the liveorgan donor.
Participants An executive group representing the NationalKidney Foundation, and the American Societies of Transplantation,Transplant Surgeons, and Nephrology formed a steering committeeof 12 members to evaluate current practices of living donortransplantation of the kidney, pancreas, liver, intestine, andlung. The steering committee subsequently assembled more than100 representatives of the transplant community (physicians,nurses, ethicists, psychologists, lawyers, scientists, socialworkers, transplant recipients, and living donors) at a nationalconference held June 1-2, 2000, in Kansas City, Mo.
Consensus Process Attendees participated in 7 assignedwork groups. Three were organ specific (lung, liver, and kidney)and 4 were focused on social and ethical concerns (informedconsent, donor source, psychosocial issues, and live organ donorregistry). Work groups' deliberations were structured by a seriesof questions developed by the steering committee. Each workgroup presented its deliberations to an open plenary sessionof all attendees. This information was stored and shaped intoa statement circulated electronically to all attendees for theircomments, and finally approved by the steering committee forpublication. The term consensus is not meant to convey universalagreement of the participants. The statement identifies issuesof controversy; however, the wording of the entire statementis a consensus by approval of all attendees.
Conclusion The person who gives consent to be a live organdonor should be competent, willing to donate, free from coercion,medically and psychosocially suitable, fully informed of therisks and benefits as a donor, and fully informed of the risks,benefits, and alternative treatment available to the recipient.The benefits to both donor and recipient must outweigh the risksassociated with the donation and transplantation of the livingdonor organ.
To assess whether the semiquantitative peripheral blood Epstein-Barr virus (EBV) polymerase chain reaction (PCR) test correlates
with post-transplant lymphoproliferative disorder (LPD), we compiled the results of the test done over a 3-year period ending
July 1997. Six hundred seventy-six tests were done on 185 patients. Four hundred-thirty tests (63%) were negative, 167 (25%)
were weak positive, 67 (10%) were moderate positive, and 12 (2%) were strong positive. Twelve of the patients developed a
lymphoproliferative disorder (LPD) during this time. The EBV PCR tests proximate to the diagnosis of LPD in the 12 patients
with EBV-positive LPD were 6 strong positive, 5 moderate positive, 1 weak positive. No patient with LPD had a negative result
at diagnosis. Stated another way, 6/12 (50%) of strong-positive PCR tests, 5/67 (7%) moderate-positive tests, and 1/167 (.6%)
of weak-positive tests correlated with LPD. Serologic evaluation for EBV done on 7 patients at the time of LPD showed low
serologic responses in 5 of the 7 patients. The EBV PCR temporally associated with the serology indicated moderate to large
viral burdens. In each patient evaluated serially, the EBV PCR test rose before the diagnosis of LPD and fell with treatment
for the disorder. In conclusion, the EBV PCR test may be used as an adjunct to the diagnosis of patients with LPD and may
be used to monitor response to therapy for the disorder.
Received August 26, 1997; accepted January 13, 1998. 相似文献
A prospective study of 25 boys who underwent circumcision for medical reason was performed. Specimens of periurethral bacterial
flora were taken before operation as well as 3 weeks after surgery, so that each boy acted as his own control. Before circumcision,
13 (52%) harboured uropathogenic organisms (Escherichia coli and other coliforms, Enterococcus spp, Proteus spp, Pseudomonas spp, and Klebsiella spp); after circumcision, none of the boys had uropathogens, the only organisms cultured from the periurethral region being
skin commensals. We postulate that circumcision converts a ‘cul-de-sac' that is a reservoir of organisms capable of causing
ascending urinary tract infection into a surface colonised by natural skin organisms. This study provides circumstantial evidence
supporting the idea that circumcision in well-selected patients may confer protection from urine infection.
Accepted: 15 March 1997 相似文献
PURPOSE: Renal cancer response to interleukin 2 (IL-2) therapy and patient survival has been correlated with tumor histology and carbonic anhydrase IX (CAIX) expression. In an effort to confirm and expand these observations, we examined CAIX expression in pathology specimens from renal cancer patients who had previously received IL-2 therapy. EXPERIMENTAL DESIGN: Paraffin-embedded tissue sections of renal cancer were immunostained with the MN-75 monoclonal antibody to CAIX and expression levels were correlated with histologic findings and clinical outcome. RESULTS: Tissue specimens were obtained from 66 patients; 27 of whom (41%) had responded to IL-2-based therapy. Fifty-eight specimens were assessed as clear cell, with 56, 33, and 4 having alveolar, granular, and papillary features, respectively. Twenty-four (36%), 31 (47%), and 11 (17%) were classified into good, intermediate, and poor prognosis groups according to the Upton pathology model. Forty-one specimens (62%) had high CAIX expression. Twenty-one of 27 (78%) responding patients had high CAIX expressing tumors compared with 20 of 39 (51%) nonresponders (odds ratio, 3.3; P = 0.04). Median survival was prolonged (P = 0.04) and survival >5 years was only seen in high CAIX expressers. In patients with intermediate pathologic prognosis, all nine responders had high CAIX expression versus 11 of 22 nonresponders. A resultant group with good pathologic prognosis alone or with intermediate pathologic prognosis and high CAIX contained 26 of 27 (96%) responders compared with 18 of 39 (46%) nonresponders (odds ratio, 30; P < 0.01) and exhibited longer median survival (P < 0.01). CONCLUSIONS: CAIX expression seems to be an important predictor of outcome in renal cell carcinoma patients receiving IL-2-based therapy and may enhance prognostic information obtained from pathology specimens. 相似文献