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Biomedical subjects

L Brasile

Publications and source records attributed to L Brasile.

49 records · Page 3Linked to original sources
PubMed1981

Clinical significance of antimonocyte antibody in kidney transplant recipients.

Monocytes appear to contain an antigen system very similar to the "cell-specific" antigen system previously identified on the vascular endothelial cell (VEC). By using a crossmatch technique with monocytes as the target cell, we tested for the presence of antibody to donor vascular endothelial cell antigens in kidney transplantation recipients, as well as performed mixed lymphocyte cultures, and T and B cytotoxicity testing. This technique detected clinically significant sensitization in some (living related) donor-recipient combinations not detected with standard T and B lymphocyte techniques. Patients with positive monocyte crossmatches but negative T or B lymphocyte crossmatches have a very high incidence of severe rejection and graft failure.

Antibodies↗
PubMed1980

The significance of mixed lymphocyte culture in related renal transplantation.

Eighty-one donor-recipient pairs were evaluated prior to renal transplantation to obtain histocompatibility profiles. Standard tissue typing was used to detect serologically defined A and B locus antigens, and mixed lymphocyte cultures were employed to detect lymphocyte defined antigens. Results of both tests were correlated with each other and with allograft rejection. It was shown that as serologically defined histocompatibility at the A and B loci decreases, both the rate of graft rejection and the percentage of high mixed lymphocyte culture stimulation increase. Within each serologically defined category were found patients with a high and a low stimulation index in mixed lymphocyte culture. Regardless of the degree of serologically defined histocompatibility, patients with a high stimulation index had a statistically significant higher graft rejection rate than did patients with a low stimulation index. It appears that the mixed lymphocyte culture assay is a method superior to standard tissue typing in predicting renal allograft rejection with related donors, and therefore all potential donors for renal transplantation should be screened, utilizing the mixed lymphocyte culture technique.

Adolescent↗
PubMed1979

A hospital food-borne outbreak of diarrhea caused by Bacillus cereus: clinical, epidemiologic, and microbiologic studies.

An outbreak of diarrhea involving 28 patients occurred in two wards of a chronic disease hospital. The illness was characterized by abdominal cramps and watery diarrhea without vomiting or fever. An epidemiologic investigation suggested food-borne intoxication and incriminated turkey loaf served at the preceding evening meal as the source of the outbreak. Bacillus cereus was isolated both from the stool of all 14 symptomatic patients who were cultured and from turkey loaf. No other enteropathogens were found. The isolate of B. cereus was shown to elaborate an enterotoxin that caused fluid secretion in assays in the rabbit ileal loop and suckling mice and that also caused a positive response in the Y-1 adrenal cell assay. B. cereus is an enteropathogen that should be sought in outbreaks of food-related gastroenteritis. This organism affects the gastrointestinal tract probably by the elaboration of enterotoxins.

Aged↗
PubMedDate not supplied

Potential of repairing ischemically damaged kidneys ex vivo.

Therapies that would accelerate recovery from ischemic injury could positively impact the number of kidneys procured from non-heart-beating donors. An acellular warm (32 degrees C) perfusion was used to deliver growth factors to canine kidneys damaged by 2 hours of warm ischemia. Fibroblast growth factors 1 and 2 were selected for activation of the tyrosine kinases because of their known receptor-specific binding in the kidney, metabolic regulation, and mitogenic effect. During 24 hours of ex vivo perfusion at near-normothermia, oxidative metabolism was sufficiently restored to the ischemically damaged tissue to support upregulation of cellular processes dependent on new synthesis. The junctional integrity protein, ZO-1 was used to determine recovery of cytoskeletal integrity. The upregulation of proliferating cell nuclear antigen was used as a marker for recovery of synthetic functions. This modulation of both injury and repair proteins in the damaged kidneys was dependent on new synthesis. The observed modulation resulting in normalization of the cytoskeletal integrity correlated with outcomes in that when the "repaired" kidneys were reimplanted, they provided life-sustaining function. In contrast, when warm ischemically damaged control kidneys without treatment, with subsequent hypothermic perfusion or warm perfused in the absence of growth factors, were reimplanted the result was nonviability. The results of this study suggest that the administration of growth factors during 24 hours of near-normothermic, acellular perfusion, in the absence of concordant inflammation, triggers pathways for new synthesis leading to cellular recovery rather than resulting in cell death.

Animals↗
PubMedDate not supplied

Ex vivo evaluation of organ function after cold ischemia.

An ex vivo perfusion of kidneys was performed at 34 degrees C after cold ischemia of 24, 48, 72, and 96 hours to evaluate organ function prospectively. The prospective evaluation of organ function followed static hypothermic storage of the kidneys in a solution representative of clinical organ preservation. The warm perfusion was performed with an acellular solution that supports oxidative metabolism of sufficient magnitude to restore urine flow ex vivo. The parameters of organ function evaluated included oxygen consumption, vascular resistance, urine flow, and glomerular filtration rates, which were correlated with the histologic findings. The results of this study suggest that kidneys exposed to 24 and 48 hours of cold ischemia demonstrated oxygen consumption rates and vascular dynamics similar to control kidneys without exposure to cold ischemia, indicating cell viability. When the cold ischemic period was increased beyond 48 hours of preservation, substantially reduced rates of oxygen consumption and increased vascular resistances were observed, representing a loss of viability confirmed histologically. However, organ function was found to be impaired after exposure to cold ischemia at every time point. These results suggest that cold ischemic exposure had a negative impact on immediate renal function once oxidative metabolism was restored, which was exacerbated as the cold ischemic period was extended. Furthermore, these findings suggest that although the renal cells were viable after cold ischemic exposure, the viability status did not result in immediate function. Therefore, assessment of an organ based solely on cell viability may falsely indicate a functional organ. It will be necessary to identify parameters of organ function that can distinguish reversibility from non-reversibility of cellular impairment to distinguish permanent functional disturbances. The ability to predict organ function prospectively will be an important aspect of any effective future expansion of the organ donor pool.

Animals↗
PubMedDate not supplied

I: Negative effect of cold ischemia on initial renal function.

Correlation between post-transplant function and exposure to cold ischemia (CI) during preservation has been reported. We attempted to identify the effect of CI on renal function using exsanguinous metabolic support (EMS) technology, to eliminate effects of reperfusion complications. Small bovine kidneys were used to evaluate 4 vs. 24 hours of CI, after warm ischemic (WI) exposure of <15, 30 or 60 minutes. After CI, kidneys were warm perfused (30 degrees C to 32 degrees C) ex vivo using EMS technology. Restored renal metabolism and function were quantified by oxygen consumption, urine production, glomerular filtration rate (GFR), and hemodynamic characteristics. The results demonstrate a CI-associated lag phase in the restoration of metabolism, in which the longer cold-preserved kidneys exhibit a lower initial rate of oxygen consumption. However, after 3 hours of EMS perfusion there was no significant difference in the O2 consumed, urine flow, GFR, perfusion flow, or pressure between the kidneys stored for 4 or 24 hours. An initial reduction in metabolism after longer CI may influence the severity of actual reperfusion injury during transplantation. Therefore, these results provide preliminary evidence suggesting that an acellular warm temperature reperfusion ex vivo may enhance restoration of cellular metabolism and minimize damage from the cold seen upon actual reperfusion.

Animals↗
PubMedDate not supplied

II: Ex vivo viability testing of kidneys after postmortem warm ischemia.

Future approaches to expand the organ donor pool with marginal and nonheartbeating donors, will be dependent upon prospective organ evaluation. Restoration of metabolism by preservation at warmer temperatures could potentially provide the window for such evaluation. Using a small bovine model, kidneys were subjected to either < 15, < 30 or < 60 minutes of warm ischemia (WI) followed by cold ischemia (CI) in ViaSpan. After WI and CI, kidneys were transitioned to a warm temperature perfusion (30 degrees C to 32 degrees C) using exsanguinous metabolic support (EMS) technology. Restored renal metabolism and function was assessed by oxygen consumption, glucose consumption, urine production, glomerular filtration rate, and hemodynamic characteristics. The results of this study suggest that it is feasible to distinguish viable from nonviable organs ex vivo by assessing renal metabolism and function during warm preservation using EMS technology.

Animals↗
PubMedDate not supplied

Ex vivo resuscitation of kidneys after postmortem warm ischemia.

An ex vivo resuscitation of kidney function following substantial post mortem warm ischemia was attempted with the ultimate goal of overcoming the ischemic barriers in organ retrieval for transplantation. The resuscitation technology involved reperfusion at 32 degrees C with an acellular solution to reinstitute oxidative metabolism of sufficient magnitude to restore function after a substantial postmortem warm ischemic insult. The ability to resuscitate renal function at various time periods postmortem was evaluated. Resuscitation parameters included perfusion pressures, vascular flow rates, vascular resistances, restoration of diuresis with concordant urinary creatinine concentrations, and blinded histologic evaluations. The results of this study suggest that it may one day be feasible to resuscitate organs following as much as 2 hr of postmortem warm ischemia for clinical transplantation. An expanded donor pool consisting of allografts resuscitated post mortem from what is now considered to be the "non retrieval donor" could help alleviate the chronic organ shortage. Furthermore, since organs resuscitated ex vivo at 32 degrees C exhibited ongoing metabolism, which was artificially supported rather than inhibited by traditional hypothermia, diuresis was restored. The ability to collect and analyze urine during organ resuscitation and preservation may present the opportunity to assess organ function prospectively.

Animals↗