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Biomedical subjects

C M Miller

Publications and source records attributed to C M Miller.

At least 55 records · Page 3Linked to original sources
PubMed2000

Th1/Th2 cytokines and ICAM-1 levels post-liver transplant do not predict early rejection.

Th1 derived cytokines IFN-gamma and IL-2, Th2 cytokine IL-4, and ICAM-1 have been implicated in liver allograft rejection. In order to determine whether monitoring of cytokine profiles during the first days post-liver transplant can predict early rejection we measured IFN-gg, IL-2, sIL-2 receptor, IL-4 and ICAM-1 in 22 patients, in plasma samples obtained within 4 h after liver perfusion (baseline) and between postoperative days (POD) 3-6. ICAM-1 and sIL-2R levels at POD 3-6 were significantly higher than at baseline but did not differ in presence or absence of rejection. Mean percentage increase of ICAM-1 levels was significantly lower in patients with Muromonab-C3 Orthoclone OKT3 (J.C. Health Care) (OKT3) whereas percentage increase of sIL-2R levels was higher in OKT3-treated patients. IFN-gamma levels at POD 3-6 increased from baseline while IL-4 levels were unchanged. Levels of IFN-gamma, IL-4 and their ratios did not correlate with rejection or immunosuppressive therapy. Thus, Th1/Th2 cytokine monitoring during the first week post-transplant does not predict early rejection and immunosuppressive therapy is the predominant factor affecting ICAM and sIL-2R levels after liver transplantation.

Female↗
PubMed2000

Liver transplantation at Mount Sinai.

Nearly 2000 liver transplants have been performed over the past 12 years at Mount Sinai, with a recent exponential growth in living donor surgeries. Living-donor liver transplantation has emerged as an important option for our patients with end-stage liver disease. We are only beginning to recognize fully the advantages that 'scheduled' liver transplantation can offer. In this era of severe cadaver organ shortages, living donation offers patients the option of liver replacement in a timely fashion, before life-threatening complications of hepatic failure and/or carcinoma progression prohibit transplantation. The next era of transplantation at Mount Sinai will bring significant increases in the number of transplants performed with living donors, with projections of over 50% of the total transplants each year expected to involve living donations. We are committed to offering this option while recognizing that donor safety remains paramount and cannot be overemphasized. Proper donor and recipient selection, as well as surgical experience are imperative to success with this technically demanding procedure. Recurrent disease after transplantation, particularly with hepatitis C, remains a challenge clinically. Further investigations into the pathogenesis of the rapid progression of recurrent hepatitis C need to be addressed. Living donor transplantation could be an important option for these patients and would allow timely transplantation and the potential for improved survival in patients with hepatocellular carcinoma.

Adult↗
PubMed1999

Selective modulation of B-cell activation markers CD86 and I-Ak on murine draining lymph node cells following allergen or irritant treatment.

It is well known that T cells are key effector cells in the development of allergic contact dermatitis. However, we and others have shown that mice exposed to contact allergens show a preferential increase in B lymphocytes in the draining lymph nodes (DLN) as seen by an increase in the percentage of B220+ or IgG/IgM+ cells. The purpose of the present investigation was to determine whether chemical allergens, in contrast to irritants, would modulate B-cell activation markers, CD86 and I-Ak, on B cells isolated from DLN of treated mice using the local lymph node assay (LLNA) protocol. Mice were treated on the ears for 3 consecutive days with concentrations of allergens (1-chloro-2,4-dinitrobenzene, alpha-hexylcinnamaldehyde, 4-ethoxymethylene-2-phenyl-2-oxazoline-5-one, and trinitrochlorobenzene), or irritants (benzalkonium chloride and sodium lauryl sulfate), which caused an increase in the number of DLN cells. The DLN were excised 72 h following the final chemical treatment, and the cells were prepared for analysis by flow cytometry. In mice treated with allergens an increase in the median intensity of I-AK and CD86 on B220+ or IgG/IgM+ B cells was observed compared to mice treated with irritants or vehicles. Mice treated with allergens demonstrated an increase in the median intensity of CD86 on B220+ B cells that was dose dependent and peaked at 72 h following the final allergen treatment. The increase in the median intensity of I-AK also was dose dependent but peaked at 96 h. Finally, T and B cells isolated from both allergen- and irritant-treated mice demonstrated an increase in [3H]thymidine incorporation compared to vehicle-treated and naïve mice at 72 h following the final chemical treatment. The results suggest that B cells isolated from DLN of allergen-treated mice are activated and proliferating. Analysis of B-cell activation markers may be useful in differentiating allergen and irritant responses in the draining lymph nodes of chemically treated mice.

Allergens↗
PubMed1999

Probing activation of the prokaryotic arginine transcriptional regulator using chimeric proteins.

The major transcription factors controlling arginine metabolism in Escherichia coli and Bacillus subtilis, ArgR and AhrC, respectively, are homologous multimeric proteins that form l -arginine-dependent DNA-binding complexes capable of repressing transcription of the biosynthetic genes (both), activating transcription of catabolic genes (AhrC only) or facilitating plasmid dimer resolution (both). Multimerisation and l -arginine binding are associated with the C-terminal 70-80 residues; the N-terminal regions contain a winged helix-turn-helix DNA-binding domain. We have constructed chimeric genes in which the sequences for the N and C-terminal domains have been swapped. The resultant chimeric proteins and their corresponding native proteins have been analysed for their ability to multimerise and bind DNA operator sites in an L-arginine-dependent fashion. Gel filtration and equilibrium sedimentation analysis are consistent with the formation of hexamers by all four proteins in the presence of L-arginine and at high protein concentrations (>100 nM monomer). The hexamer sedimentation coefficients suggest that there is a reduction in molecular volume upon binding L-arginine, consistent with a conformational change accompanying an allosteric activation of DNA-binding. In the absence of L-arginine or at lower protein concentrations, the hexamers are clearly in rapid equilibrium with smaller subunits, whose dominant species appear to be based on trimers, as expected from the crystal structure of the ArgR C-terminal fragment, with the exception of the ArgR-C chimera, which apparently dissociates into dimers, suggesting that in the intact protein the DNA-binding domains may have a significant dimeric interaction. The hexamer-trimer Kdis in the micromolar range, suggesting that trimers are the principal species at in vivo concentrations.DNA binding by all four proteins has been probed by gel retardation and DNase I footprinting analysis using all three types of naturally occurring operators: biosynthetic sites encompassing two 18 bp ARG boxes separated by 2 bp; biosynthetic sites containing two such boxes and a third 18 bp ARG box at a distance of 100 bp downstream, i.e. within the structural gene; and finally a catabolic operator which contains a single ARG box site. The data show that all four proteins bind to the operators at the expected regions in an L-arginine-dependent fashion. From the apparent affinities of the chimeras for each target site, there is no obvious sequence-specificity associated with the N-terminal domains; rather the data can be interpreted in terms of differential allosteric activation, including DNA binding in the absence of L-arginine.Remarkably, the proteins show apparent "anti-competition" in the presence of excess, specific DNA fragments in gel retardation. This appears to be due to assembly of an activated form of the protein, probably hexamers, on the operator DNA. The data are discussed in terms of the current models for the mode of action of both native proteins.

Amino Acid Sequence↗
PubMed1999

Characterization of p53 in Chinese hamster cell lines CHO-K1, CHO-WBL, and CHL: implications for genotoxicity testing.

Since the p53 gene function is critical to how a cell responds to DNA damage, we investigated the p53 status in Chinese hamster cell lines commonly used in genotoxicity tests for cytogenetic damage around the world. These included: Chinese hamster ovary K1 (CHO-K1), Chinese hamster ovary WBL (CHO-WBL), and Chinese hamster lung (CHL) cells. The results of DNA sequencing, protein analysis, and cell cycle analysis demonstrate that the CHO-K1 and CHO-WBL cell lines have mutant p53 sequence [a mutation in codon 211 in exon 6 resulting in a change from Thr (ACA) to Lys (AAA)], mutant protein (high spontaneous levels that are non-inducible after X-irradiation), and mutant function (lack of G1 checkpoint). Interestingly, the CHL cell line has a completely wild-type p53 DNA sequence. However, the CHL cells have an abnormally high spontaneous level of wild-type p53 protein expression that is not inducible after X-irradiation, yet there is some evidence of G1 delay after irradiation. The protein data suggests that p53 in CHL cells is not being regulated normally, and thus is probably not functioning normally. The mechanism leading to this abnormal regulation of p53 in CHL cells clearly does not involve mutation in the p53 gene. Overall, the CHL cell line may be similar to the CHO cell lines, in that they all appear to have abnormal p53 function. Further work is needed to determine whether the presence of spontaneously high levels of wild-type p53 in CHL cells results in a difference in response to DNA damage (quantitatively or qualitatively) compared to the p53 mutant CHO cell lines.

Animals↗
PubMed1999

Safe transplantation of blood type A2 livers to blood type O recipients.

BACKGROUND: Transplantation of blood type A subgroup 2 (A2) livers into non-A recipients has not been reported previously. A2 to O renal transplantation has been reported, with early results including some accelerated rejections and graft losses. This has led some to selectively offer A2 renal transplantation only for patients with low anti-A titers. Given the different clinical behavior of liver allografts to preformed antibody, we felt that such restriction was unnecessary. METHODS: We performed six cases of A2 to O liver transplantation with no augmented immunomodulation or restriction with regard to antibody titers. Clinical courses, anti-A titers, rejection rates, and graft and patient survival were evaluated. RESULTS: All six patients had high pretransplant anti-A titers (>1:8), and all six grafts functioned normally. There were nine rejections in the six patients, of which three were severe (steroid-resistant) and five were late (>90 days). No rejection was vascular, and no grafts were lost, with mean follow-up of 665 days. In one patient who had anti-A antibody measured at the time of rejection IGM titers increased from baseline. Currently all patients are home with normal function. CONCLUSIONS: We found that transplantation of blood group A2 livers into blood group O recipients is safe and can be performed without graft loss and without regard to anti-A titer level. The rate of acute cellular rejection is high in this small series, and a significant proportion of these events were late or required OKT-3. We did not rely on plasmapheresis or anti-A titer determinations. However, the potential for late rejection prompts us to consider the addition of a third immunosuppressive agent. The transplantation of A2 livers into O recipients can partially compensate for the more frequent use of O livers in recipients from other blood groups.

ABO Blood-Group System↗
PubMed1999

The effect of continuous drug exposure on the immune response to Trichostrongylus colubriformis in sheep.

The effect of albendazole (ABZ)-capsule (CRC) administration on parasite establishment and immunity to ABZ-resistant (RES) and -susceptible (SUS) T. colubriformis was measured in Romney lambs. During 12 weeks of twice-weekly dosing with 3000 parasite larvae (L3), eggs were observed in faeces from CRC-treated and untreated lambs given RES L3, but not CRC-treated lambs given SUS L3. Following the period of trickle challenge all lambs were drenched and, 1 week later, dosed with 20000 SUS L3. Resulting worm burdens were higher in control lambs than in those previously treated with CRCs and challenged with SUS, which in turn were higher than those in the CRC-treated or -untreated lambs previously challenged with RES L3. During the period of trickle challenge, the number of peripheral eosinophils and titres of anti-L3 and anti-adult antibody were raised only in those groups given RES L3. There was no effect of CRC administration. Following drench and challenge, antibody titres and eosinophil numbers increased in the control animals but not in those groups which had received previous trickle infection. The results demonstrate that the larval challenge alone resulted in incomplete though substantial protection against subsequent parasite challenge. The use of CRCs may potentially impact on subsequent animal performance and selection for anthelmintic resistance through a reduced level of immunity.

Albendazole↗
PubMed1999

Hereditary hemochromatosis in liver transplantation.

A candidate gene, HFE, was recently described in patients with hereditary hemochromatosis (HH) and found to contain a missense mutation leading to a cysteine to tyrosine substitution (C282Y). A second mutation, H63D, was also found in the gene. This study was undertaken to determine the HFE genotype in liver transplant recipients clinically diagnosed with HH and those incidentally found to have increased iron deposition in their explanted livers and to evaluate whether biochemical or histological hepatic iron indices (HIIs) correlated with homozygosity for the C282Y mutation. We identified 15 patients clinically diagnosed with various liver disorders other than HH who had increased liver iron deposits among 918 adult patients who underwent liver transplantation from 1988 to 1995. Four additional patients were clinically diagnosed as having HH. Archival explant liver tissue was evaluated for the histological HII according to the method of Deugnier et al, in which an index greater than 0.15 suggests homozygosity for HH. The HII was computed according to established methods, with a value greater than 1.9 suggesting homozygosity for HH. A portion of liver tissue was subjected to DNA genotyping using polymerase chain reaction-amplified products. Two of 4 patients with clinically suspected HH were homozygous for C282Y, and 2 patients had neither mutation. One of the 15 patients not suspected to have HH was a C282Y homozygote, 1 was a C282Y heterozygote, 6 were H63D heterozygotes, and 7 had neither mutation. The histological HII was consistent with HH in 13 patients, whereas the HII was consistent with HH in 6 patients. Thus, in patients with end-stage liver disease, despite fulfilling the established clinical criteria for HH using biochemical and histological parameters, only a minority of patients were homozygous for the C282Y mutation. Hepatic iron overload may result from other causes, and in end-stage liver disease, an elevated HII may not accurately predict HH. Other factors that either control or lead to iron absorption may explain iron overload in these patients.

Adult↗
PubMed1999

Living related liver transplantation for acute liver failure in children.

The mortality rate among children with acute liver failure (ALF) on the waiting list for liver transplantation is high. We present our experience with living related donor liver transplantation (LRD-LT) in children who required urgent transplantation for ALF. Between December 1995 and July 1997, 6 children underwent LRD-LT for ALF. Cause of liver failure, recipient and donor demographics, clinical and laboratory data, surgical details, complications, and 6-month and 2-year graft and patient survival were recorded. Five boys and 1 girl received left lateral segment grafts from their parents. The mean age was 4 +/- 2.8 years (range, 1 to 9 years). ALF was caused by Wilson's disease in 1 patient and sickle cell intrahepatic cholestasis syndrome in 1 patient; in 4 patients, the cause was unknown. All patients had mental status changes; 2 were on life support. Mean pretransplantation liver function test values were: alanine aminotransferase, 972 +/- 565 U/L (normal, 1 to 53 U/L), total bilirubin, 31.3 +/- 12.4 mg/dL (normal, 0.1 to 1.2 mg/dL), prothrombin time, 34.3 +/- 12.4 seconds (normal, 10.8 to 13.3 seconds), international normalized ratio, 8.46 +/- 5.4 (normal < 2), and fibrinogen, 109 +/- 23.9 mg/dL (normal, 175 to 400 mg/dL). The donors were 5 mothers and 1 father. The mean donor age was 32.5 +/- 7.6 years (range, 19 to 40 years). No donor required blood transfusion, and no donor had any early or late postoperative complications. The donors' mean hospital length of stay was 5 days. In five cases, grafts were blood group-compatible; 1 child received a blood group-incompatible graft. All grafts functioned immediately. No patient had hepatic artery or portal vein thrombosis or biliary complications. The child who received a mismatched graft died of infection of the brain caused by Aspergillus spp at 22 days posttransplantation with a functioning graft. The child with ALF caused by sickle cell intrahepatic cholestasis syndrome developed outflow obstruction 3 months posttransplantation and required retransplantation; he eventually died of vascular complications related to his primary disease. Four children are alive at a mean follow-up of 27 months (range, 14 to 36 months). LRD-LT for children with ALF facilitates timely transplantation without drawing on cadaveric donor resources. The established safety record of LRD-LT made this option appealing to both physicians and parental donors.

Adult↗
PubMed1999

Successful liver transplantation from a donor with brodifacoum intoxication.

We describe our use of a liver allograft from a donor who died of intracranial hemorrhage after brodifacoum ingestion. Because brodifacoum can remain in the human body for months, the recipient's posttransplantation coagulation profiles and serum brodifacoum levels were monitored closely. Her posttransplantation course was excellent, with no coagulation problem. At 15 months posttransplantation, she is well, with normal liver function and coagulation profile. We conclude that brodifacoum toxicity is not a strict contraindication to liver donation.

4-Hydroxycoumarins↗
PubMed1999

Hepatic epithelioid hemangioendothelioma: resection or transplantation, which and when?

Hepatic epithelioid hemangioendothelioma (HEHE) is a rare tumor with an unpredictable course and prognosis. The aim of this study is to describe our experience with liver resection, as well as transplantation, in the treatment of this tumor. We retrospectively analyzed the clinical features, pathological findings, and postoperative results in a series of 11 patients presenting between 1990 and 1998. Five patients (45%) presented with abdominal pain, 3 patients (27%) with jaundice and ascites, and the rest were asymptomatic. Computed tomography or magnetic resonance imaging showed localized lesions in 2 patients (18%) and multifocal disease in the others. Seven patients (64%) had extrahepatic lesions, detected either by preoperative imaging or discovered at exploration. Two resections of apparently localized lesions were followed by rapid and aggressive recurrence. Five patients were treated with transplantation, including 1 patient who had previously undergone resection. Of these 5 patients, 2 patients are currently free of detectable disease, 1 patient who had severe ascites and jaundice is now asymptomatic with stable extrahepatic lesions, and 2 patients (including 1 who had previously undergone a resection) died of tumor recurrence. One patient with advanced tumor died while waiting for transplantation. The remaining 4 patients are free of symptoms and have stable hepatic and extrahepatic disease. HEHE is nearly always multifocal, and our results with resection were dismal. Because of the unpredictable nature of the tumor, the indications for transplantation in patients without liver-related symptoms should be carefully evaluated. Nevertheless, extrahepatic disease should not be an absolute contraindication for liver transplantation in patients with severe liver dysfunction.

Female↗
PubMed1999

Transmission of factor VII deficiency through liver transplantation.

The liver is the primary site of synthesis for the majority of coagulation factors. There are published accounts of liver donor-to-recipient transmission of protein C deficiency with dysfibrinogenemia and factor XI deficiency. In this article, we report what we believe to be the first observation, of transmission of factor VII deficiency, a rare, autosomal recessive coagulation disorder, from an affected liver donor to a naive liver recipient. At 300 days after transplantation, the recipient remains with an isolated prolongation of the prothrombin time and a below-normal level of factor VII, and has had no bleeding complications.

Adult↗
PubMed1999

The establishment rate of Ostertagia circumcincta and Trichostrongylus colubriformis in lactating Romney ewes.

The ability of lactating Romney ewes to resist establishment of ingested infective-stage larvae (L3) of Ostertagia circumcincta and Trichostrongylus colubriformis was measured in the field. Three groups of seven single-lamb-bearing ewes were selected on the basis of uniformity of lambing date from a large flock held on pasture. Either 2, 4 or 6 weeks after parturition, groups of ewes were dosed with 24000 L3 of known oxfendazole-resistant parasite strains; 12000 of each species. Ten to 14 days later the ewes, along with their lambs, were transferred from the field to indoor pens. Twenty-five days after the challenge dose the ewes were drenched with oxfendazole to remove any field-derived infection and 3 days later slaughtered for worm counts. Mean establishment of the resistant parasites was low at all times, with the highest rate recorded being 6.1% for O. circumcincta 2 weeks after parturition. Establishment of O. circumcincta 4 and 6 weeks after parturition, and of T. colubriformis at all times, never exceeded 2%. By comparison, mean establishment in lambs held indoors and parasite free for 13 weeks prior to infection, was 24.9% and 47.1% for O. circumcincta and T. colubriformis, respectively. These results indicate that the lactating ewes were exhibiting a substantial ability to prevent establishment of ingested larvae. The results of this and other similar studies suggest that the dynamics of parasitism in lactating Coopworth and Romney ewes in New Zealand is substantially different to that in Merino ewes in Australia, and that these differences influence optimal strategies for the management of anthelmintic resistance in the two countries.

Animals↗
PubMed1999

Cytokines, nitric oxide, heat shock proteins and virulence in Toxoplasma.

Elucidating the factors that play important roles in the expression of virulence by parasites is crucial to understanding disease pathogenesis and to developing control strategies rationally. Here, Kate Miller, Nick Smith and Alan Johnson, using Toxoplasma gondii as a model, argue that the interactions between the immune system and 70 kDa heat shock proteins of apicomplexan parasites profoundly influence parasite virulence.

Animals↗
PubMed1999

The immune response of sheep to larval challenge with Ostertagia circumcincta and O. ostertagi.

One of three groups of sheep was challenged twice-weekly with infective-stage larvae (L3) of the sheep parasite O. circumcincta, another with the cattle parasite O. ostertagi while the third received no larval challenge. Positive faecal egg counts (FEC) and a rise in plasma pepsinogen levels were observed only in those animals given O. circumcincta. Anti-O. circumcincta L3 IgG titres were rapidly elevated during parasite challenge with either O. circumcincta or O. ostertagi. Throughout the experiment, no rise in anti-adult IgG titres or eosinophil numbers was observed in peripheral blood in any group. On evidence of self-cure of the trickle-infection, determined by a reduction in FEC, all groups were drenched and challenged with 15,000 O. circumcincta L3. No effect of previous challenge on parasite establishment or FEC was observed, although egg viability was significantly reduced in both groups given prior challenge. Significant differences in adult female worm length were observed between groups. Those recovered from animals previously challenged with O. circumcincta were shorter than from those given O. ostertagi which were in turn shorter than those from previously unchallenged animals. In utero egg counts were significantly lower in worms from animals previously challenged with O. circumcincta than in those from unchallenged control animals. The results indicate that a level of immunity to O. circumcincta can be conferred by exposure to O. ostertagi.

Abomasum↗
PubMed1999

Correlation between von Willebrand factor levels and early graft function in clinical liver transplantation.

Cold preservation/reperfusion leads to sinusoidal endothelial cell (SEC) activation and damage in nearly every liver transplantation; the extent of these changes influences early graft function. Upon reperfusion, activated SEC show increased expression of adhesion molecules, including von Willebrand factor (vWF) which is released into the circulation. This study was designed to evaluate the levels of vWF measured in the caval effluent and correlate these findings with known markers of SEC damage and early graft function. Data were obtained from 35 patients undergoing orthotopic liver transplantation (LTx). Two samples were taken from each patient for measurement of vWF: a) from the portal vein immediately prior to reperfusion; and b) from the first 50 ml of the caval effluent. Commercial assays were used to measure vWF, as well as hyaluronic acid (HA), thrombomodulin (TM), IL-1 beta, IL-6, IL-8 and TNF-alpha. Patients were divided into two groups based on early graft function. Poor early graft function (PEGF) was defined as a peak aspartate transaminase (AST) or alanine transaminase (ALT) level > 2500 U/L during the first three postoperative days (POD) and a prothrombin time (PT) > 16 s on POD 2 (n = 8). The remaining 27 patients had good early graft function (GEGF). In patients with GEGF, vWF levels dropped significantly between the two time points. This change was not observed in those with PEGF. A positive linear correlation was observed in the PEGF group between vWF and HA and IL-6. The different pattern of change in vWF between the two groups, as well as the positive correlation between HA, IL-6 and vWF in PEGF, suggest that vWF may be a useful marker of early graft function.

Adult↗
PubMed1998

Kinetic analysis of secretory protein traffic and characterization of golgi to plasma membrane transport intermediates in living cells.

Quantitative time-lapse imaging data of single cells expressing the transmembrane protein, vesicular stomatitis virus ts045 G protein fused to green fluorescent protein (VSVG-GFP), were used for kinetic modeling of protein traffic through the various compartments of the secretory pathway. A series of first order rate laws was sufficient to accurately describe VSVG-GFP transport, and provided compartment residence times and rate constants for transport into and out of the Golgi complex and delivery to the plasma membrane. For ER to Golgi transport the mean rate constant (i.e., the fraction of VSVG-GFP moved per unit of time) was 2.8% per min, for Golgi to plasma membrane transport it was 3.0% per min, and for transport from the plasma membrane to a degradative site it was 0.25% per min. Because these rate constants did not change as the concentration of VSVG-GFP in different compartments went from high (early in the experiment) to low (late in the experiment), secretory transport machinery was never saturated during the experiments. The processes of budding, translocation, and fusion of post-Golgi transport intermediates carrying VSVG- GFP to the plasma membrane were also analyzed using quantitative imaging techniques. Large pleiomorphic tubular structures, rather than small vesicles, were found to be the primary vehicles for Golgi to plasma membrane transport of VSVG-GFP. These structures budded as entire domains from the Golgi complex and underwent dynamic shape changes as they moved along microtubule tracks to the cell periphery. They carried up to 10,000 VSVG-GFP molecules and had a mean life time in COS cells of 3.8 min. In addition, they fused with the plasma membrane without intersecting other membrane transport pathways in the cell. These properties suggest that the post-Golgi intermediates represent a unique transport organelle for conveying large quantities of protein cargo from the Golgi complex directly to the plasma membrane.

Aluminum Compounds↗