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J Fung

Publications and source records attributed to J Fung.

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

Comparative long-term evaluation of tacrolimus and cyclosporine in pediatric liver transplantation.

BACKGROUND: In this report, we compare the long-term outcome of pediatric liver transplantation (LTx) patients maintained with tacrolimus-based and with cyclosporine (CsA)-based immunosuppressive therapy. We examine long-term patient and graft survival, the incidence of rejection, and immunosuppression-related complications. METHOD: There were 233 consecutive primary LTx in children (ages <18 years) performed between October 1989 and December 1994 with tacrolimus-based immunosuppressive therapy (Group I). These were compared with 120 consecutive primary LTx performed with CsA-based immunosuppressive therapy between January 1988 and October 1989(Group II). Children in both groups were followed until July 1999. Mean follow-up was 91.41+/-17.7 months (range 55.6-117.8) for Group I, and 128+/-6.1 months (range 116.7-138.6) for Group II. RESULTS: At 9 years of follow-up, actuarial patient and graft survival were significantly improved (patient survival 85.41% in Group I vs. 63.8% in Group II, P=0.0001; graft survival Group I 78.9% vs. 60.8% Group II, P=0.0003) and the rate of re -transplantation was significantly lower among patients in Group I (12% in Group I vs. 22.5% in Group II P=0.01). Children in Group I also experienced a significantly reduced incidence of acute rejection (0.97 per patient Group I vs. 1.5 per patient Group II P=0.002) and significantly less steroid resistant acute rejection episodes (3.1% in Group I vs. 8.6% in Group II P=0.0001). The mean steroid dose was significantly lower in Group I compared with Group II at all time points (P=0.0001) after LTx. Freedom from steroid was also significantly higher in Group I compared with Group II at all time points after LTx (ranging from 78% to 84% in Group I and 9% to 32% in Group II during a 1- to 7-year posttransplant period P=0.0001). The rate of hypertension was significantly lower in Group I than Group II (P=0.0001), and the severity of hypertension (need for more than one anti-hypertensive medication) was also significantly lower in Group I than Group II (P=0.0001). Although the rate of posttransplant lymphoproliferative disorder (PTLD) was not significantly different (13.7% Group I vs.8.3% Group II, P=0.13), the survival after PTLD was significantly better for Group I at 81.2% than for Group II at 50% after 5 years (P=0.034). Conclusion. The results suggest that tacrolimus-based therapy provides significant long-term benefit to pediatric LTx patients, evidenced by significantly improved patient and graft survival, reduced rate of rejection, and hypertension with lower steroid doses.

Cause of Death↗
PubMed2000

Long-term results after conversion from cyclosporine to tacrolimus in pediatric liver transplantation for acute and chronic rejection.

UNLABELLED: Tacrolimus is beneficial in liver transplantation for reversing steroid-resistant acute rejection, and for controlling the process of chronic rejection in allograft recipients receiving Cyclosporine- (CyA) based regimens. Very little is known about the long-term efficacy of tacrolimus in pediatric transplantation after conversion from CyA. Our study examines the long-term outcome after conversion to tacrolimus for acute or chronic rejection in pediatric liver transplant (LTx) recipients. METHOD: Seventy-three children (age < 18 years) receiving their primary LTx under CyA between August 1989 and April 1996 were converted to tacrolimus for ongoing acute rejection (n=22, group I) or chronic rejection (n=51, group II). Mean age at the time of conversion was 10.2+/-5.5 years with a mean interval from LTx to conversion of 3.5+/-2.9 (range 0.5-10.1 years). There were 33 boys and 40 girls. All patients were followed until June 1999. Mean follow-up was 97.3+/-17.4 months (range 62.4-118.9 months). RESULTS: Overall 5-year actual patient survival was 78.1% and 8-year actuarial survival was 74.6%. Patients converted to tacrolimus therapy to resolve acute rejection (group I) experience significantly better patient and graft survival at 5 and 8 years than those converted to resolve chronic rejection (group II). Eight-year patient survival and graft survival was 95.5 and 90.9% for group I compared to 74.6 and 53.5% for group II, respectively (long rank P=0.035 and 0.01, respectively). Nearly 75% of children were weaned off steroids after conversion. There was a marked improvement in hypertension, gum hyperplasia, hirsutism, and cushingoid appearance. One child in group I (4.5%) and four children in group II (7.8%) developed posttransplant lymphoproliferative disorder after conversion. There was an improvement in growth in children who were less than the age of 12 years at the time of conversion and who were weaned off steroids; more significantly girls responded more favorably than boys. CONCLUSION: The benefit of transplantation is maintained long-term after conversion to tacrolimus for acute or chronic rejection. The response rate was significantly better in group I as compared with group 11. Marked improvement in growth, hypertension, and reversal of the brutalizing effects of CyA was noted after conversion to tacrolimus. The results suggest that early conversion of pediatric liver transplant patients is warranted for the treatment of acute and chronic rejection, and for improvements in quality of life.

Adolescent↗
PubMed2000

Comparative induction of CYP1A1 expression by pyridine and its metabolites.

We compared pyridine and five of its metabolites in terms of (i) in vivo induction of CYP1A1 expression in the lung, kidney, and liver in the rat and (ii) in vitro binding to, and activation of, the aryl hydrocarbon receptor (AhR) in cytosol from rat liver or Hepa1c1c7 cells. Following a single 2.5 mmol/kg ip dose of either pyridine, 2-hydroxpyridine, 3-hydroxypyridine, 4-hydroxypyridine, N-methylpyridinium, or pyridine N-oxide, CYP1A1 activity (ethoxyresorufin O-deethylase), protein level (as determined by Western blotting), and mRNA level (as determined by Northern blotting) were induced by pyridine, N-methylpyridinium, and pyridine N-oxide in the lung, kidney, and liver. The induction by N-methylpyridinium or pyridine N-oxide was comparable to or greater than that by pyridine in some tissues. 2-Hydroxypyridine and 3-hydroxypyridine caused tissue-specific induction or repression of CYP1A1, whereas 4-hydroxypyridine had no effect on the expression of the enzyme. Pyridine and its metabolites elicited weak activation of the aryl hydrocarbon receptor in a gel retardation assay in cytosol from rat liver but not Hepa 1c1c7 cells. However, the receptor activation did not parallel the in vivo CYP1A1 induction by the pyridine compounds, none of which inhibited binding of ¿(3)H2,3,7, 8-tetrachlorodibenzo-p-dioxin to AhR in a competitive assay in rat liver cytosol. The findings are consistent with a role of pyridine metabolites in CYP1A1 induction by pyridine but do not clearly identify the role of aryl hydrocarbon receptor in the induction mechanism.

Animals↗
PubMed2000

Effect of gestational and lactational 2,3,7, 8-tetrachlorodibenzo-p-dioxin exposure on the level and catalytic activities of hepatic microsomal CYP1A in prepubertal and adult rats.

We determined the inducibility, as well as the persistence of the induction, of hepatic microsomal CYP1A1 and CYP1A2 (by western blot analysis), and their catalytic activities (as measured by resorufin ether O-dealkylation) in prepubertal (25-day-old) and adult (120-day-old) offspring of timed-pregnant Sprague-Dawley rats treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). TCDD treatment was subcutaneous, at a low dose of 0.1 microg/kg, on gestational days 7, 14, and 20, and on lactational days 7 and 14. CYP1A1 protein was induced significantly (23-fold) in prepubertal but not in adult offspring of TCDD-exposed dams, whereas ethoxyresorufin O-deethylase (EROD) activity, which is CYP1A1-preferential, was induced less extensively (5-fold) and slightly (1.7-fold) in the prepubertal and adult offspring, respectively. Benzyloxyresorufin O-debenzylase (BROD) activity, which is CYP2B-preferential but has been reported to be catalyzed by CYP1A1, was also induced 5- and 6-fold in prepubertal and adult offspring, respectively, of TCDD-exposed dams. However, the induced BROD activity was neither inhibited by antibody against CYP1A1 nor accompanied by an elevated level of microsomal CYP2B. CYP1A2 was induced slightly only in prepubertal offspring of TCDD-treated dams. There was suggestive evidence of enhanced lipid peroxidation in hepatic microsomes from prepubertal but not adult offspring of TCDD-treated dams. These data showed that in utero plus lactational TCDD exposure effected transient induction of hepatic microsomal CYP1A1 but sustained induction of BROD activity, which may be catalyzed by enzymes other than CYP1A or CYP2B.

Animals↗
PubMed2000

Biopsy of marginal donor kidneys: correlation of histologic findings with graft dysfunction.

BACKGROUND: Kidney biopsies are being used to evaluate marginal donors, but rigorous statistical validation of this practice with multivariate analysis has not been performed. METHODS: To analyze histologic parameters in 78 donor biopsies for their ability to predict graft dysfunction, we used a proportional odds model that included both donor and recipient factors. Glomerulosclerosis was categorized into grades 0, 1, 2, and 3, corresponding to 0, 1-10%, 11-20%, and 21-30% global sclerosis, respectively. The degrees of interstitial fibrosis, tubular atrophy, arteriosclerosis, and arteriolar hyalinosis were graded from 0 to 3+, using definitions suggested by the Banff Schema of allograft pathology. RESULTS: Increasing donor age was associated with higher glomerulosclerosis, tubular atrophy, and arteriosclerosis. Kidneys with any degree of interstitial fibrosis were 2.6 times [odds ratio (OR)] more likely to experience a worse outcome at 6 months (P = 0.02). This association held up after correction for acute rejection (OR 2.5, P = 0.03) and high panel-reactive antibody (OR 3.4, P = 0.006), However, the OR was reduced to 1.9 (P = 0.15) after controlling for recipient age. With each increment in the grade of glomerulosclerosis, the odds for a worse outcome at 12 months increased to 2.3 (P = 0.005). The value for OR became 2.0 (P = 0.03) when controlling for recipient age (P = 0.01), 2.4 (P = 0.005), when controlling for acute rejection, and 2.3 (P = 0.006) when controlling for high panel-reactive antibody. CONCLUSIONS: Histopathological parameters present in donor biopsies can independently predict post-transplant graft function. Implications for the pool of donor organs available for transplantation are discussed.

Adolescent↗
PubMed2000

Conversion to neoral for neurotoxicity after primary adult liver transplantation under tacrolimus.

BACKGROUND: Neurological complications after orthotopic liver transplantation (OLTX) have remained a major concern in a small proportion of patients. The etiology of these complications is often thought to be multifactorial: the influence of calcineurin inhibitors is occasionally thought to play an important role. When neurotoxicity occurs after OLTX under tacrolimus, it is usually a minor complication and responds readily to a reduction in the dosage of or a temporary withdrawal of tacrolimus. However, neurotoxic complications occasionally do not respond to this conventional process. Neoral is a microemulsion formulation of cyclosporine. It has more consistent pharmacokinetic parameters and improved bioavailability when compared with conventional cyclosporine. The aim of the present report was to evaluate the role of Neoral in OLTX recipients with neurotoxic complication who failed to respond to a reduction in the dosage of tacrolimus. METHOD: Between August 1995 and November 1997, 330 adults (age >18 years) received primary OLTX under tacrolimus-based immunosuppression (mean age 52.6+/-11.4 years). There were 190 men and 140 women. Twenty-three (7%) patients (mean age 53.2+/-11.8 years; 17 men, 6 women) were converted to Neoral (mean 35+/-41 days after OLTX). These patients were followed until June 1998 (mean follow-up 22.7+/-7.8 months). RESULTS: Four (17.4%) patients died during the follow-up period, and two patients underwent retransplantation. Neurological symptoms improved in all patients who survived. Adequate trough concentrations were achieved in all patients with p.o. Neoral. Nine (39%) patients experienced rejection episodes after conversion. Six (26.1%) patients were converted back to tacrolimus because of ongoing rejection (n=3), retransplantation (n=2), or persistent nausea and vomiting (n=1) without recurrence of the original neurological complication. CONCLUSION: Neurological complications after OLTX disorders that occur under tacrolimus and that fail to respond to a reduction in the dosage can be treated safely by conversion to Neoral. However, the rate of rejection is up to 39%, and patients can often be converted back to tacrolimus without recurrence of the original neurological complication.

Adult↗
PubMed2000

Effective control of hepatic bleeding with a novel collagen-based composite combined with autologous plasma: results of a randomized controlled trial.

HYPOTHESIS: A novel collagen-based composite of bovine microfibrillar collagen and bovine thrombin combined with autologous plasma is more effective than standard hemostasis (collagen sponge applied with pressure) in controlling diffuse hepatic bleeding after hemihepatectomy or segmental resection of the liver. DESIGN: Randomized controlled trial. SETTING: Seven university-affiliated medical centers. PATIENTS: Sixty-seven adult patients scheduled for hemihepatectomy or segmental resection who received hemostatic intervention with an investigational treatment (n = 38) or control (n = 29). INTERVENTION: Bleeding hepatic tissue was managed in all control subjects with a collagen sponge with manual pressure. Subjects in the experimental group had the sprayable liquid composite intraoperatively applied to the surgical site. The liquid immediately formed a collagen-fibrin gel that was used without concomitant tamponade. MAIN OUTCOME MEASURES: Hemostatic success was defined as the proportion of subjects in each treatment group who achieved complete hemostasis within 10 minutes. Success rates and median times required to achieve controlled bleeding (ie, slight oozing) and complete hemostasis were compared between treatment groups. RESULTS: All 38 subjects in the experimental group achieved complete hemostasis within 10 minutes compared with only 69% (20/29) of control subjects (P<.001). The median time to controlled bleeding was approximately 4 times longer (250 vs 62 seconds) for control subjects than for experimental group subjects (P<.001). The median time required to achieve complete hemostasis also favored the experimental group (150 vs 360 seconds; P<.001). No adverse events related to the use of the experimental hemostatic agent were detected. CONCLUSIONS: The experimental composite is more effective at controlling and stopping diffuse hepatic bleeding than a collagen sponge applied with pressure; it may be a useful hemostatic agent for patients undergoing hemihepatectomy, segmental resection, and related surgical procedures.

Adult↗
PubMed2000

Functional Cyp2e1 is required for substantial in vivo formation of 2,5-hexanedione from n-hexane in the mouse.

Neurotoxicity of n-hexane is mediated by its metabolite 2,5-hexanedione (2,5-HD). Cytochrome P4502E1 (CYP2E1) has been suggested but not shown to be involved in the formation of the metabolite. An objective of the current study was to assess the essentiality of CYP2E1 for in vivo 2,5-HD formation from n-hexane. This was accomplished by comparing urinary levels of the gamma-diketone in n-hexane-treated mice in which the Cyp2e1 gene has been deleted (Cyp2e1-/-) with that in n-hexane-treated wild-type (Cyp2e1+/+) mice. 2,5-HD was detectable not as the free compound but as further metabolites, at levels that were comparable in both strains of mice, following a daily 200 mg/kg i.p. dose of the alkane for 10 days. Continued daily n-hexane treatment resulted in increased urinary levels of 2,5-HD metabolites in Cyp2e1+/+ but not in Cyp2e1-/- mice. Only in Cyp2e1+/+ mice and only on day 21 of n-hexane treatment was a trace level of unchanged 2,5-HD detected. 3-Hexanol was the only other n-hexane metabolite detected in the mice but its concentration was higher in Cyp2e1-/- than in Cyp2e1+/+ mice. In n-hexane-treated rats, in contrast to mice, multiple metabolites of the alkane, including unchanged 2,5-HD, were detected. The results indicate that substantial in vivo formation of 2,5-HD from n-hexane in the mouse requires CYP2E1, and suggest that further detoxification of the metabolite may be very efficient in this species.

Adhesives↗
PubMed2000

Genome scan identifies a locus affecting gamma-globin level in human beta-cluster YAC transgenic mice.

Genetic factors affecting postnatal gamma-globin expression--a major modifier of the severity of both beta-thalassemia and sickle cell anemia--have been difficult to study. This is especially so in mice, an organism lacking a globin gene with an expression pattern equivalent to that of human gamma-globin. To model the human beta-cluster in mice, with the goal of screening for loci affecting human gamma-globin expression in vivo, we introduced a human beta-globin cluster YAC transgene into the genome of FVB/N mice. The beta-cluster contained a Greek hereditary persistence of fetal hemoglobin (HPFH) gamma allele, resulting in postnatal expression of human gamma-globin in transgenic mice. The level of human gamma-globin for various F1 hybrids derived from crosses between the FVB/N transgenics and other inbred mouse strains was assessed. The gamma-globin level of the (C3HeB/FeJ x FVB/N)F1 transgenic mice was noted to be significantly elevated. To map genes affecting postnatal y-globin expression, we performed a 20-centiMorgan (cM) genome scan of a (C3HeB/FeJ x FVB/N)F1 transgenics x FVB/N backcross, followed by high-resolution marker analysis of promising loci. From this analysis we mapped a locus within an 18-cM interval of mouse Chromosome (Chr) 1 (LOD = 4.3) that contributes 10.9% of variation in gamma-globin level. Combining transgenic modeling of the human beta-globin gene cluster with quantitative trait analysis, we have identified and mapped a murine locus that impacts on human gamma-globin level in vivo.

Animals↗
PubMed2000

Multilocus genetic analysis of single interphase cells by spectral imaging.

Numerical chromosome aberrations are detrimental to early embryonic, fetal and perinatal development of mammals. When fetuses carrying a chromosomal imbalance survive to term, an aberrant gene dosage typically leads to stillbirth or causes a severely altered phenotype. Aneuploidy of any of the 24 chromosomes will negatively impact on human development, and a preimplantation and prenatal genetic diagnosis test should thus score as many chromosomes as possible. Since cells available for analysis are likely to be in interphase, we set out to develop a rapid enumeration procedure based on hybridization of chromosome-specific probes and spectral imaging detection. The probe set was chosen to allow the simultaneous enumeration of ten chromosome types and was expected to detect more than 70% of all numerical chromosome aberrations responsible for spontaneous abortions, i.e., human chromosomes 9, 13, 14, 15, 16, 18, 21, 22, X, and Y. Cell fixation protocols were optimized to achieve the desired detection sensitivity and reproducibility. We were able to resolve and identify ten separate chromosomal signals in interphase nuclei from different types of cells, including lymphocytes, uncultured amniocytes, and blastomeres. In summary, this study demonstrates the strength of spectral imaging, allowing us to construct partial spectral imaging karyotypes for individual interphase cells by assessing the number of each of the target chromosome types.

Blastomeres↗
PubMed2000

Outcome of preimplantation genetic diagnosis of translocations.

OBJECTIVE: To review 35 cases of preimplantation genetic diagnosis (PGD) of translocations with several methods, including telomeric probes. DESIGN: Retrospective study. SETTING: Clinical IVF laboratory. PATIENT(S): Thirty-five couples with one partner carrying a chromosomal translocation. INTERVENTION(S): PGD of translocation after polar-body or embryo biopsy. MAIN OUTCOME MEASURE(S): Pregnancy outcome. RESULT(S): Several trends were observed. First, PGD can achieve a statistically significant reduction in spontaneous abortion, from 95% to 13%. Second, the chances of achieving pregnancy are correlated with 50% or more of the embryos being chromosomally normal. Third, patients with robertsonian translocations produced fewer abnormal gametes and more pregnancies than did patients with reciprocal translocations. Fourth, a new fluorescence in situ hybridization protocol for PGD of translocations, which involves applying telomeric probes, has proved adequately reliable with a 6% average error rate. CONCLUSION(S): PGD of translocations achieves a statistically significant reduction in spontaneous abortion, both for polar-body and blastomere biopsy cases. Pregnancy outcome depended on the number of normal embryos available for transfer, with patients having <50% abnormal embryos achieving the most pregnancies. Because robertsonian translocations caused fewer abnormal embryos than reciprocal translocations, they also resulted in higher rates of implantation.

Abortion, Spontaneous↗
PubMed2000

Composite liver--small bowel allografts with preservation of donor duodenum and hepatic biliary system in children.

BACKGROUND/PURPOSE: Liver and intestinal transplantation is commonly required for children with intestinal failure who suffer concomitant total parenteral nutrition (TPN)-induced liver failure. Retrieval of such composite allografts using previously described "standard techniques" mandates reconstruction of the biliary system with a defunctionalization loop of the proximal allograft jejunum. The occasional posttransplant biliary complications have been associated with significant morbidity and mortality. Also, size matching has limited the pool of donor organs for this patient population. To improve outcome and increase the donor pool the authors have utilized a duodenal-sparing composite liver small bowel allograft technique (DLSBTx) by preserving the head of the pancreas and the pancreatic-duodenal arteries. This precludes a biliary drainage procedure. METHODS: Nine children (5 girls, 4 boys), with a mean age of 1.4 years (range, 1 to 17.4 years) received a DLSBTx. In 2 patients the liver was reduced; 1 patient received the whole pancreas. The mean recipient weight at the time of transplantation was 17.4 kg (range, 6.6 to 49.8 kg). The mean age and mean weight for donors was 7.9 years (range, 3 days to 22 years) and 25 kg (range, 4 to 70 kg), respectively. All transplants were performed under tacrolimus and steroid immunosuppression. RESULTS: With a mean follow-up of 419 days (range, 5 to 795 days), patient and graft survival rates are 78% and 67%, respectively. One patient underwent a combined retransplantation with the standard technique 31 days after the primary allograft was destroyed by a native pancreatic fistula. Currently, all surviving recipients are at home and off TPN. DLSBTx allowed the expansion of the donor pool by transplanting 6 patients with donor to recipient weight ratio > or =1 and utilizing 2 less than 5-kg donors, including a neonatal donor. In 55% of the patients, chemical pancreatitis was observed during the early postoperative period. None of the duodenal allografts experienced signs of ischemia or leak. CONCLUSIONS: The technical advantages of this procedure include avoidance of a biliary reconstruction and simplification of the operative procedure. This, together with the feasibility of split or reduced liver grafting promises to increase the donor pool from neonates to adults.

Adolescent↗
PubMed2000

Liver resection combined with excision of vena cava.

BACKGROUND: This study was designed to review our experience with combined partial hepatectomy and vena caval replacement for primary and metastatic liver tumors. STUDY DESIGN: The medical records of all the patients who underwent liver resection and excision of the vena cava over a period of 13 years and 4 months at a single institution were analyzed. The types of tumors fell into four categories: 1) metastatic, 2) primary leiomyosarcoma of the inferior vena cava, 3) tumors with direct extension to the liver, and 4) cholangiocarcinoma. RESULTS: The perioperative mortality was 11% related to technical complications and hepatic insufficiency. Other important complications included biliary fistula and liver abscess; patients recovered from these complications without sequelae. Six of nine patients are alive with a followup from 6 months to 156 months (median 66.5 months), and three of them are free of disease. The most common sites of recurrence were lung, liver, and brain. The patients with leiomyosarcoma of the cava and pheochromocytoma who underwent these combined procedures had the longest survival. CONCLUSIONS: This small series confirms the feasibility of obtaining longterm survival after excision of tumors that have involved portions of the liver and the vena cava. Innovative variations on the method of vena caval replacement and increased awareness of these complex surgical techniques will expand the indications of hepatic resection.

Adult↗
PubMed2000

The mystique of hepatic tolerogenicity.

The evolution of clinical transplantation has hinged on 2 seminal turning points. The first was the demonstration in 1953 by Billingham, Brent, and Medawar that chimerism-associated tolerance could be induced deliberately in neonatal mice by infusing adult donor hematolymphopoietic cells. This discovery escalated in a straight line over the next 15 years to successful bone marrow transplantation in humans. The second turning point was the demonstration that organ allografts could self-induce tolerance under an umbrella of immunosuppression, or in some species without immunosuppression. Unfortunately, it was incorrectly concluded by most immunologists and surgeons that bone marrow and organ engraftment involved different immune mechanisms. In a derivative error, it became widely believed that the tolerogenicity of the liver differed fundamentally not only from that of bone marrow but also from that of other whole organs. These errors became dogma and were not corrected until low level donor leukocyte chimerism was found in humans and animals bearing long surviving liver, kidney, heart, and other kinds of allografts. With successful bone marrow transplantation, the trace population consisted of recipient rather than donor leukocytes. Thus, the consequences of organ and bone marrow engraftment were mirror images. From these observations, it was proposed that the engraftment of all kinds of organs as well as bone marrow cells (BMC) involved host versus graft (HVG) and graft versus host (GVH) reactions with reciprocal induction of variable degrees of specific non-reactivity (tolerance). The maintenance of the tolerance was an active and ongoing process requiring the persistence of the transplanted fragment of the donor immune system. The immune responsiveness and unresponsiveness to both organ and bone marrow allografts are thought to be governed by the migration and localization of leukocytes. The clarifying principles of tranplantation immunology that have emerged from the chimerism studies are relevant to the adaptive immune response to microbial, tumor, allogeneic, and self antigens. These principles should be used to guide efforts to systematically induce tolerance to human tissues and organs, and perhaps ultimately to xenografts.

Animals↗
PubMed2000

Case-specific, breakpoint-spanning DNA probes for analysis of single interphase cells.

Balanced reciprocal translocations are known to interfere with homolog pairing in meiosis. Many individuals carrying such chromosomal abnormalities suffer from reduced fertility or spontaneous abortions and seek help in the form of assisted reproductive technology. Although most translocations are relatively easy to detect in metaphase cells, the majority of embryonic cells biopsied in the course of in vitro fertilization (IVF) procedures are in interphase. These nuclei are, thus, unsuitable for analysis by chromosome banding or painting using fluorescence in situ hybridization (FISH). Our assay, based on FISH detection of breakpoint-spanning DNA probes, identifies translocations in interphase nuclei by microscopic inspection of hybridization domains. Probes are selected that span the breakpoint regions on normal homologs. The probes should hybridize to several hundred kilobases of DNA flanking the breakpoint. The two breakpoint-spanning DNA probes for the translocation chromosomes are labeled in separate colors (e.g., red and green). The translocation event producing two fused red/green hybridization domains can then be detected in interphase cell nuclei using a fluorescence microscope. We applied this scheme to analyze somatic and germ cells from 21 translocation patients, each with distinct breakpoints. Here, we summarize our experience and provide a description of strategies, cost estimates, as well as typical time frames.

Blastomeres↗