Search PubMed⌕ Search

Biomedical subjects

C M Miller

Publications and source records attributed to C M Miller.

At least 145 records · Page 8Linked to original sources
PubMed1994

Obviation of prereperfusion rinsing and decrease in preservation/reperfusion injury in liver transplantation by portal blood flushing.

Liver allografts are traditionally rinsed with cold lactated Ringer's (LR) prereperfusion to clear K(+)-rich preservation solution from the hepatic vasculature. LR has been shown, however, to be injurious to the graft. By restoring portal blood flow without rinsing and discarding the initial blood traversing the liver (PB flush), we sought to eliminate rinsing without inducing hyperkalemia. Between August 1988 and December 1992, 481 OLTx were performed in 412 pts. Four rinsing methods were used sequentially: group 1 (157 pts)--low-flow-rate cold LR rinse (500 ml, 100 ml/min via standard i.v. tubing at 100 cm H2O [LFLR]) during lower caval anastomosis; Group 2 (120 pts)--LFLR as in group 1, at reperfusion, 500 ml PB flush via IVC catheter; group 3 (66 pts)--high-flow-rate LR rinse (500 ml, 1 L/min using large-bore tubing with 100 cm H2O rinsing pressure [HFLR]), PB flush as in group 2; Group 4 (62 pts)--no LR rinse; PB flush as in groups 2 and 3. Poor early graft function (PEGF) was defined as peak ALT or AST > 2500 U or PT > 16 sec (on POD 2); PEGF causing re-OLTx or death within 14 days was called primary nonfunction (PNF). Group 1 and Group 3 had high PEGF rates. Group 4 had significantly less PEGF than Group 1, with a trend toward a significant difference from Group 3. In Group 1, 3 pts. had intraoperative hyperkalemic cardiac arrest; this did not occur when PB flush was performed. PB flush without prior rinsing optimizes graft function without risk of hyperkalemia. LR rinse, alone or followed by PB flush, is unnecessary and may be deleterious.

Adolescent↗
PubMed1994

Adoptive cellular therapy of human breast and colorectal tumor targets using ex vivo activated memory T lymphocytes with potentiation by cis-diamminedichloroplatinum(II).

Autolymphocyte therapy (ALT) is adoptive cellular therapy of cancer using ex vivo activation of autologous peripheral blood lymphocytes (PBL). Memory T cells are the principal effector population in ALT, with in vivo activity in patients with metastatic renal cell carcinoma (RCC) and melanoma, and ex vivo cytotoxicity against autologous tumor targets. However, the noncytolytic lymphocyte portion of ex vivo-activated memory T cells (ALT cells) may also contribute as antitumor effectors. Pretreatment of murine and human tumor cells ex vivo with chemotherapeutic agents can enhance their susceptibility to antitumor lymphocytes ex vivo and in vivo. To determine whether cis-diamminedichloroplatinum(II) (DDP) could enhance ex vivo antitumor effects of ALT cells by immunomodulation, human breast and colorectal carcinoma target cells were derived from both primary and metastatic surgical specimens and incubated in complete medium (CM) with DDP or in CM alone (control group). Viability of each group was confirmed by trypan blue-dye exclusion test. ALT cells were prepared from autologous PBL at surgery. Primary and metastatic tumor cells from each group were used as targets for ALT cells and levels of interferon-gamma (IFN-gamma) release were measured as a determination of antitumor effect and recognition. Primary tumor target cells incubated in DDP showed enhanced antitumor effects and recognition by autologous ALT cells, as measured by the IFN-gamma assay compared to non-DDP-treated controls. Metastatic autologous tumor target cells demonstrated less IFN-gamma release than did the primary targets, although this was enhanced by pre-treating metastatic tumor targets with DDP. ALT cells demonstrated minimal IFN-gamma release when incubated with allogeneic tumor targets. These data suggest that autotumor recognition of metastatic tumor targets is comparable to that of primary lesions following ex vivo pretreatment of metastatic cells with nonlethal doses of certain chemotherapeutic agents. DDP may somehow alter the physical properties of target cells, rendering them susceptible to immune-mediated attack and the combination of ALT and DDP may lead to increased therapeutic efficacy in patients with metastatic breast and colon cancer.

Breast Neoplasms↗
PubMed1994

Glutathione S-transferases as markers of salicylanilide resistance in isolates of Fasciola hepatica.

A possible link between the level of glutathione S-transferase (GST, E.C. 2.5.1.18) activity and the development of salicylanilide resistance in Fasciola hepatica was investigated. Various isolates of F. hepatica with varying susceptibilities to salicylanilides were isolated and maintained in the laboratory. Individual flukes of these isolates were surveyed for their level of GST activity and a correlation between the level of GST activity and drug efficacy was found. In contrast to most other studies, a decrease in GST activity was associated with an increase in drug resistance. Evidence was collected to show that this may be a selective process since flukes which had survived exposure to rafoxanide and closantel in vivo (in sheep) had lower activity levels of GST than flukes from untreated sheep. Treatment with other flukicides (oxyclozanide, luxabendazole and triclabendazole) did not have this effect. Furthermore, in vivo treatment with closantel induced selection of particular isoenzymes in different isolates of F. hepatica having different degrees of susceptibility to closantel. However, no single isoenzyme or isoenzyme profile was associated with resistance and, in total, up to 8 different isoenzymes could be present in a single isolate. Thus, GST has some potential as a marker enzyme for salicylanilide resistance in F. hepatica. However, the precise role of GST in resistance is unclear and the extensive inter- and intra-isolate variation in activity levels and isoenzyme characteristics of this enzyme indicate the need for considerably more study before application in field situations.

Animals↗
PubMed1994

Eimeria maxima: ELISA and western blot analyses of protective sera.

Infection of chickens with Eimeria maxima induces the production of parasite-specific antisera which can be used passively to protect naive chickens against infection. Globulin fractions of these antisera can also be used passively to protect chickens. Similarly, intramuscular injection of soybean lectin affinity purified gametocyte antigens of E. maxima in Freund's Complete Adjuvant induces production of antibodies which are maternally transferred and thereby protect hatchlings against E. maxima. ELISA analyses of serum pools having varying protective capacities revealed good correlations between passive protection and levels of anti-unsporulated oocyst, anti-sporulated oocyst, anti-merozoite and anti-gametocyte antibodies. Western blotting demonstrated that the sera mainly recognized a number of high molecular weight antigens in all developmental stages and that the intensity of the reactions reflected the degree of protection induced by the sera. Sera from birds immunized with gametocyte antigens also recognized high molecular weight antigens from all the developmental stages, with banding patterns remarkably similar to those observed for sera from infected birds. Taken together, these results indicate that antibodies can protect against infection with E. maxima and these antibodies may recognize and act against asexual and/or sexual stages of the parasite.

Animals↗
PubMed1994

Maternal transmission of immunity to Eimeria maxima: western blot analysis of protective antibodies induced by infection.

Infection of breeding hens with Eimeria maxima induces production of parasite-specific antibodies which are transferred, via the egg yolk, to hatchling chicks. These antibodies (immunoglobulin G) are highly protective, mediating up to a 97% reduction in oocyst excretion in challenged hatchlings. However, the degree of maternally derived immunity transferred by the hens to their offspring declines with increasing time after infection of the hens. This decline in immunity is directly related to declining immunoglobulin G titers. However, sera from highly protected hatchlings recognize only a very few E. maxima proteins on Western blots (immunoblots). In particular, a 230-kDa protein band is outstanding for its association with maternally derived immunity to E. maxima in hatchlings. This band was excised from a sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) preparative gel of crude merozoite protein extract. The SDS-PAGE cutout was emulsified in Freund's adjuvant and injected, intramuscularly, into six breeding hens on two occasions, 2 weeks apart. Eggs were collected from these hens 28 to 39 days after the second injection, and the hatchlings from these eggs were challenged with 150 sporulated oocysts of E. maxima. Subsequent oocyst excretion in these hatchlings was, on average, 54% lower than oocyst excretion by control chicks but only 37% lower (significant at P < 0.05) than that by chicks from hens sham immunized with Freund's adjuvant. The latter result is apparently due to the ability of the adjuvant to induce production of antibodies which recognize Eimeria spp. and thereby transfer some degree of protection to hatchlings. These experiments indicate that protective, maternally derived immunoglobulin G antibodies may be useful for the identification of putative anticoccidial vaccine candidates.

Animals↗
PubMed1994

Maternal transmission of immunity to Eimeria maxima: enzyme-linked immunosorbent assay analysis of protective antibodies induced by infection.

Vaccination of broiler chickens against Eimeria infection is problematic because of the need to ensure that birds are protected from the time of hatching. We have therefore investigated the feasibility of protecting hatchling broilers via maternal transfer of protective antibodies from hens to their offspring. Oral infection of broiler breeder hens with 20,000 sporulated Eimeria maxima oocysts caused production of antibodies which were passed into the egg yolk and subsequently to hatchlings. The level of specific antibodies in the yolks to unsporulated oocysts, sporulated oocysts, merozoites, and gametocytes was assessed by enzyme-linked immunosorbent assays. The levels in yolks of antibodies to all developmental stages peaked 3 to 4 weeks after infection of the hens. Groups of 10 hatchlings were challenged at 3 days of age by oral infection with 100 sporulated E. maxima oocysts. In the first experiment, the mean 4-day (days 6 to 9 post-infection) total number of oocysts excreted in the feces of chicks from eggs collected 3 weeks after infection of the hens was (0.6 +/- 0.4) x 10(6) (mean +/- standard error) compared with (9.9 +/- 1.4) x 10(6) for the progeny of uninfected hens, which represents a greater than 90% reduction. However, oocyst excretion by chicks from eggs collected 7 or 8 weeks after infection of the hens was only 47 or 68% lower than control values, reflecting declining levels of protective antibodies. In a second experiment, in which the hens were somewhat older and pretreated by intramuscular injection of saline in the emulsifying agent, Arlacel A, the period for which protective antibodies were transferred to hatchlings was prolonged. Thus, oocyst excretion by challenged hatchlings from eggs collected for an 8-week period after infection of the hens was more than 90% lower than oocyst excretion by control chicks, and even hatchlings of eggs collected 19 weeks after infection of the hens showed a 60% reduction in oocyst output. In both experiments, the levels of immunoglobulin G (IgG) antibodies to all developmental stages in yolks or hatchling sera were very strongly correlated with maternally derived immunity to E. maxima. In contrast, parasite-specific IgM or IgA was not detectable, either in egg yolk or egg white. These results demonstrate the ability of IgG antibodies to protect against E. maxima in poultry, thus raising the possibility of using protective maternally derived IgG antibodies to identify potentially protective parasite antigens and indicating the feasibility of using maternal immunization as a means for parasite control.

Animals↗
PubMed1994

Quantitative nuclear morphometry, Markovian texture descriptors, and DNA content captured on a CAS-200 Image analysis system, combined with PCNA and HER-2/neu immunohistochemistry for prediction of prostate cancer progression.

One hundred and twenty-four localized prostate cancer patients operated on at Johns Hopkins Hospital (JHH) since 1975 were identified. The sample was optimized for evaluation of prostate cancer progression. Based upon accurate clinical histories, these radical prostatectomy patients included 50 progressors and 74 non-progressors using appearance of serum PSA as an indication of recurrence (mean follow-up = 8.6 +/- 1.8 years, range 7-15 years). All patients included in the study had no involvement of their seminal vesicles or lymph nodes at the time of prostatectomy. Average time to progression was 3.6 +/- 2 years, range of 1-8 years. Using paraffin-embedded specimens, several five micron sections were cut and placed on Probe-On slides; one slide was H&E-stained and the other was Feulgen-stained. The H&E and Feulgen-stained slides were screened and "dotted" by pathologists at JHH and CytoDynostics, Inc. A CAS-200 Image analysis system (Cell Image Systems, Elmhurst, IL) equipped with a Cell Measurement Program version 1.2 beta, was used to capture the Feulgen-stained images and to perform the calculations. From the "dotted" areas, 150 cancer cells were selected for measurement of DNA content and 27 nuclear morphometric shape and size factors, including 21 Markovian chromatin texture variables. Additional sections were used for immunochemistry staining with an alkaline phosphatase streptavidin-biotin complex stain to detect and quantitate cancer cells binding monoclonal antibodies directed against proliferating cell nuclear antigen (PCNA) and HER-2/neu antigen. All data were entered into a statistical program (STATA) for further analysis and univariate and multivariate statistical analysis was performed using logistic regression and its stepwise variant. The biomarkers of greatest utility to detect progressors when analyzed univariately included post-operative Gleason score (p = < 0.0001), HER-2/neu antigenicity (p = 0.0147), CAS-200 DNA ploidy (p = 0.008), and twelve Markovian nuclear texture and shape features (p = < 0.0001), whereas PCNA (p = 0.160) failed. The optimal set of nuclear morphometry progression tumor features were selected using backward stepwise logistic regression estimate analysis which drops variables due to collinearity. Although post-operative Gleason score is a strong univariate predictor of progression, DNA ploidy and HER-2/neu contributed significantly to further stratification of higher risk groups within the low Gleason score subpopulation. The best Markovian features combined with post-operative Gleason score generated sensitivity = 90%, specificity = 96%, positive predictive value = 94%, negative predictive value = 93% and the area under the receiver operator curve was 0.975.

Biomarkers, Tumor↗
PubMed1994

Liver transplantation at Mount Sinai Hospital.

Liver transplantation is an exciting field of research in which evolution in surgical techniques and immunosuppression and preservation have dramatic effects on overall patient survival. Our research at Mount Sinai is focused on preventing recurrent disease, optimizing the use of new immunosuppressive agents, and improving graft function. It is our hope that our research will eventually make it possible for us to overcome the supply-demand disparity and permit us to ask "When should this patient be transplanted?" rather than the very difficult question, "Who should be transplanted?"

Adult↗
PubMed1994

Preservation injury in clinical liver transplantation: incidence and effect on rejection and survival.

The distribution of the severity of preservation injury (PI), its association with acute early rejection, and its effect on graft and patient survival were examined in 151 patients transplanted between 9/88 and 12/91. PI was graded into mild, moderate and severe using prothrombin time (PT) on the 2nd POD and peak AST and ALT levels of the first 3 days after transplant. Of the 151 patients, 104 (68.8%) had minimal, 24 (15.9%) had moderate, and 23 (15.3%) had severe PI. The rate of early rejection, within 21 days after transplant, (54.8% vs 54.2% vs 52.2%) and its timing (10.0 +/- 0.5 vs 8.8 +/- 0.8 vs 8.9 +/- 1.4 days) as well as the incidence of steroid-resistant rejection (21.4% vs 33% vs 30%) did not differ significantly among groups. Graft survival was significantly lower in the severe PI group than among patients with minimal PI at 3 months and 24 months (65.2% vs 86.2%; p < 0.05 and 58.3% vs 82.7%; p < 0.05, respectively). Patient survival at 3 and 24 months was similar among the groups (91.1% vs. 95.8% vs 86.9% and 81.9% vs 91.1% vs. 74.3%). We conclude that the cellular damage associated with preservation injury does not predispose to development of acute rejection.

Alanine Transaminase↗
PubMed1994

Neurologic complications of orthotopic liver transplantation.

Neurologic complications are frequent after liver transplantation and are the cause of significant morbidity and mortality. A substantial proportion of the neurologic complications encountered after transplant is iatrogenic--the consequence of the harsh therapeutic interventions required to maintain function of the transplanted liver. The preoperative condition of the patient is also a major determinant of the incidence and impact of neurologic complications, as is the occurrence of poor early graft function or of repeated rejection episodes that require augmented immunosuppression. By recognizing the early signs of drug-related neurotoxicity, it is often possible to preempt the development of more severe trouble. Careful perioperative fluid management, specifically related to sodium and glucose levels, may reduce the risk of CPM. As effective treatment modalities have emerged, an aggressive approach to the diagnosis of central nervous system infection has assumed increased importance. With persistent attention to the details of basic patient care as well as to the specific neurologic diagnosis, and with a commitment to intensive rehabilitation therapy, the large majority of patients who suffer neurologic complications after transplant can ultimately return to a productive life.

Cerebrovascular Disorders↗
PubMed1994

Flushing with autologous blood improves intraoperative hemodynamic stability and early graft function in clinical hepatic transplantation.

Hemodynamic instability and hyperkalemia are common after reperfusion and may cause ischemic damage on the hepatic allograft. Two techniques for flushing hepatic grafts before reperfusion were studied to evaluate their effects on intraoperative hemodynamic and metabolic status and on early graft function in 83 consecutive adult hepatic transplantations. In the first 41 patients (group 1), the hepatic grafts were rinsed with 500 milliliters of lactated Ringer's solution (LR). In the subsequent 42 patients (group 2), in addition to LR rinse, the first 500 milliliters of portal blood to flush and reperfuse the liver were drained through the cannula inserted into the donor vena cava before unclamping the vena cava. After reperfusion, the mean arterial pressure decreased 30 +/- 4 percent in group 1 versus 17 +/- 2 percent in group 2 (p < 0.02), and serum K+ increased by 1.9 +/- 0.2 in group 1 versus 0.8 +/- 0.2 milliequivalents per liter in group 2 (p < 0.01). Hyperkalemic cardiac arrest was only seen in two patients in group 1. The K+ concentration in the first 100 milliliters of discarded blood was found to be 40 +/- 2 milliequivalents per liter. The 500 milliliters of discarded blood contained 8.3 +/- 0.4 milliequivalents, which was correlated with graft liver weight (p < 0.001). Early graft function, as measured by serum glutamic-oxaloacetic transaminase, serum glutamic pyruvic transaminase, total bilirubin and prothrombin time on postoperative day No. 2, was significantly better in group 2 than in group 1 (p < 0.05). The six-month graft and patient survival rates in group 1 were 66 and 75 percent, versus 90 and 95 percent in group 2 (p < 0.01 and p < 0.02, respectively). Further flushing with 500 milliliters of autologous portal blood resulted in smaller intraoperative shifts in serum K+, greater hemodynamic stability, better graft function and improved graft and patient survival.

Adult↗
PubMed1993

Effects of charged amino acid mutations on the bimolecular kinetics of reduction of yeast iso-1-ferricytochrome c by bovine ferrocytochrome b5.

The reduction of wild-type yeast iso-1-ferricytochrome c (ycytc) and several mutants by trypsin-solubilized bovine liver ferrocytochrome b5 (cytb5) has been studied under conditions in which the electron-transfer reaction is bimolecular. The effect of electrostatic charge modifications and steric changes on the kinetics has been determined by experimental and theoretical observations of the electron-transfer rates of ycytc mutants K79A, K'72A, K79A/K'72A, and R38A (K' is used to signify trimethyllysine (Tml)). A structurally robust Brownian dynamics (BD) method simulating diffusional docking and electron transfer was employed to predict the mutation effect on the rate constants. A realistic model of the electron-transfer event embodied in an intrinsic unimolecular rate constant is used which varies exponentially with donor-acceptor distance. The BD method quantitatively predicts rate constants over a considerable range of ionic strengths. Semiquantitative agreement is obtained in predicting the perturbing influence of the mutations on the rate constants. Both the experimentally observed rate constants and those predicted by BD descend in the following order: native ycytc > K79A > K'72A > K79A/K'72A. Variant R38A was studied at a different ionic strength than this series of mutations, and the theory agreed with experiment in predicting a smaller rate constant for the mutant. In all cases the predicted effect of mutation was in the correct direction, but not as large as that observed. The BD simulations predict that the two proteins dock through essentially a single domain, with a distance of closest approach of the two heme groups in rigid body docking typically around 12 A. Two predominant classes of complexes were calculated, the most frequent involving the quartet of cytb5/ycytc interactions, Glu48-Arg13, Glu56-Lys87, Asp60-Lys86, and heme-Tml72, having an average electrostatic energy of -13.0 kcal/mol. The second most important complexes were of the type previously postulated (Salemme, 1976; Mauk et al., 1986; Rodgers et al., 1988) with interactions Glu44-Lys27, Glu48-Arg13, Asp60-Tml72, and heme-Lys79 and having an energy of -6.4 kcal/mol. The ionic strength dependence of the bimolecular reaction rate was well reproduced using a discontinuous dielectric model, but poorly so for a uniform dielectric model.

Amino Acid Sequence↗