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Biomedical subjects

D B Kaufman

Publications and source records attributed to D B Kaufman.

At least 37 records · Page 2Linked to original sources
PubMed1997

The role of PCR in the diagnosis and management of CMV in solid organ recipients: what is the predictive value for the development of disease and should PCR be used to guide antiviral therapy?

Cytomegalovirus remains a significant source of morbidity and mortality in immunocompromised hosts. The increased sensitivity of molecular diagnostic techniques (PCR, antigenemia) has resulted in our ability to detect viral replication earlier in the posttransplant period, before the onset of symptoms. With the advent of effective antiviral therapy, "preemptive therapy," guided by sensitive, early and specific predictors of CMV disease, has become a realistic objective. Although multiple studies have analyzed the sensitivity and specificity of these tests, their predictive value for the development of disease has not been defined. The purpose of this study was to evaluate the predictive value of a positive CMV PCR in the setting of solid abdominal organ transplantation. A total of 476 PCR assays were performed on 134 transplant recipients (102 kidney, 19 kidney/pancreas, 11 liver, 2 other) either as protocol serial samples or as dictated by clinical events. All samples were concomitantly analyzed using standard virological assays for CMV including culture, shell vial, and serology. Patients with any CMV seropositive donor/recipient (D/R) combination received ganciclovir prophylaxis in conjunction with antilymphocyte induction for 14 days. No subsequent CMV prophylaxis was used. The positive predictive value was 55% in all seropositive donor/recipient combinations. The highest risk group (seronegative recipient of seropositive donor) showed the highest positive predictive value, whereas seropositive recipients of either seropositive or seronegative donors showed positive predictive values of 45% and 25%, respectively. Negative predictive value was 100% for all groups. Early detection of CMV infection has important implications for patient management, including preemptive therapy, which can be guided by PCR, especially in high risk (D+/R-) patients.

Acyclovir↗
PubMed1997

Analysis of fused maxillary incisor dentition in p53-deficient exencephalic mice.

Out of a total of 21 exencephalic p53-deficient embryonic and newborn mice, 6 (28.6%) possessed fused maxillary incisor teeth. On histological analysis of the 5 examples seen on day 19.5 of gestation and newborn mice, 3 varieties were observed: an example of 'simple' fusion, 3 examples of simple fusion each of which contained a 'dens in dente' ('tooth within a tooth'), and a single example in which the fused teeth were associated with a median supernumerary incisor tooth which, while deeply indenting the labial surface of the fused teeth, was in all locations a completely separate unit. 3-D reconstructions of the fused teeth demonstrated that they were all of the fusio subtotalis variety. No gross abnormalities were observed in the other dentition in these mice. It is noted that in mice fused maxillary incisor teeth are relatively commonly associated with both hypervitaminosis A-induced and trypan blue-induced exencephaly. It is believed that the presence of dens in dente within fused maxillary incisor teeth has only once been reported in mice, and the association between fused maxillary incisor teeth and a median supernumerary incisor tooth has not previously been reported in this species.

Animals↗
PubMed1996

Early histopathology of small intestinal discordant xenografts.

A descriptive study of a new model enabling serial biopsies of ongoing hyperacute rejection of small intestinal discordant xenografts is presented. In a series of guinea-pig-to-Lewis rat small bowel xenotransplants (n=7), aboral free ends of Thierry-Vella loops constructed from the graft were sequentially biopsied at one-minute intervals up to ten minutes post-reperfusion and less frequently thereafter. In a guinea pig-to-guinea pig (n=6) isograft series, biopsy controls for preservation/ischemia-reperfusion injury were obtained. Xenoantibody sequestration in this model was evaluated in a separate series of transplants, utilizing an ELISA assay for rat anti-guinea pig natural antibodies. Pathologic evaluation revealed a unique series of events characterized with microcirculatory failure and thrombosis progressing from the submucosal vasculature to the lumen. Within the system's detection limits, complement deposition and P-selectin expression occurred as early as one minute post-reperfusion, preceding the staining for IgM and IgG. Using rat serum ELISAs, no significant difference in xenoantibody sequestration was detected between the xenograft and isograft groups. The guinea pig-to-rat discordant small bowel xenotransplantation is an efficient small animal model to dissect the very early pathophysiologic events during hyperacute rejection.

Animals↗
PubMed1996

Frequency of hyperkalemia in recipients of simultaneous pancreas and kidney transplants with bladder drainage.

Hyperkalemia is the most frequent electrolyte abnormality found in whole organ transplant recipients receiving either cyclosporine (CsA) or tacrolimus (FK506). Recipients of a simultaneous pancreas kidney (SPK) transplant with bladder drainage may be particularly susceptible to hyperkalemia secondary to sodium loss from the bladder-drained pancreas, leading to decreased sodium delivery to potassium secretory sites of the kidney. We looked at the incidence of hyperkalemia in 34 type I diabetic SPK recipients transplanted at our center over the period from 1993 to 1995 and compared this with a cohort of 25 type I diabetic recipients of a kidney alone (K(Tx)) transplant. The incidence of hyperkalemia was 73.5% in recipients of an SPK, while it was 44% in K(Tx) recipients (P<0.05). CsA levels were higher, on average, in the SPK group (339 ng/ml+/-62 versus 272 ng/ml+/-58 in the K(Tx) group, P<0.05). However, CsA levels were not different between groups at the time of hyperkalemia, 320+/-74 versus 298+/-49 for SPK and K(Tx), respectively. CsA levels at the time of hyperkalemia were not different from those at the time of normokalemia. Other medications, serum bicarbonate, and renal function were not different in the groups. SPK recipients appear to have a greater incidence of hyperkalemia than kidney alone transplant recipients. This difference cannot be explained by higher acute CsA levels, other medications, or worse renal function. The increased incidence of hyperkalemia may, in part, be secondary to decreased sodium delivery to the transplanted kidney.

Adult↗
PubMed1996

Acyclovir triphosphate inhibits the diagnostic polymerase chain reaction for cytomegalovirus.

Immunocompromised patients are frequently treated with guanine analogs such as acyclovir and ganciclovir. Acyclovir triphosphate, the active intracellular metabolite of acyclovir, exerts its antiviral effect by inhibiting herpesviral DNA polymerases through premature chain termination. PCR has recently been used for early detection of cytomegalovirus. However, we and others have experienced false-negative results for cytomegalovirus-PCR in patients on both acyclovir and ganciclovir. The impact of these agents on PCR assay is unknown. In an attempt to investigate the role of guanosine analogs in these false-negative results, we exposed the DNA-PCR for murine beta-actin, a murine CMV IE gene sequence, and a human CMV IEA1 product, to phosphorylated acyclovir derivatives. Varying concentrations of acyclovir-5'-triphosphate (final: 70-6000 microM) in the reaction mix resulted in an absence of detectable product at or above 490-670 microM. Inhibition was not observed with up to 1400 microM acyclovir-monophosphate. Increasing the Taq concentration to 10 units/100 microL stopped the inhibition. Our data demonstrate that acyclovir-5'-triphosphate inhibits PCR amplification of various gene products in a concentration-dependent manner. Furthermore, this inhibition appears to be specifically directed against the Taq polymerase and can be completely reversed by higher concentrations of the enzyme. Thus, false-negative PCR results for a viral gene product in patients under prophylaxis/treatment with acyclovir could potentially be due to contamination by acyclovir triphosphate. Therefore, negative PCR results in these patients need be interpreted with caution.

Actins↗
PubMed1996

Cyclosporine pharmacokinetics and risk of recurrent rejection in recipients of simultaneous pancreas/kidney transplants.

Recipients of a simultaneous pancreas/kidney transplant (SPK) appear to have a greater incidence of acute rejection than do recipients of a kidney-alone transplant. These patients are also susceptible to multiple rejection episodes. Because of this, optimal immunosuppression is imperative in these patients. Cyclosporine A (CsA)-based immunosuppression remains the mainstay of therapy, and therefore, optimization of this often unpredictable drug is necessary. We looked at 14 consecutive SPK recipients and assessed the utility of a single 1-month pharmacokinetic study in predicting the risk of acute rejection. Each pharmacokinetic study was analyzed by both monoclonal fluorescence polarization immunoassay (TDX) and high performance liquid chromatography (HPLC). Due to the small sample size and the high rate of primary rejection (12/14 patients), we chose a novel endpoint, that of recurrent rejection. Seven of the 14 patients studied developed recurrent rejection. The patients without recurrent rejection had significantly higher areas under the concentration curve (AUCs) than did patients with recurrent rejection: 4,663 +/- 1,460 vs. 2,454 +/- 1,717 ng-h/ml (p < 0.05) by HPLC and 6,669 +/- 2,556 vs. 3,661 +/- 1,956 ng-h/ml (p < 0.05) by TDX. We propose that a single 1-month AUC has potential utility in identifying a subset of SPK patients with poor CsA absorption at risk for recurrent rejection.

Adult↗
PubMed1995

The specificity of monoclonal fluorescence polarization immunoassay for cyclosporine in recipients of simultaneous pancreas-kidney transplants.

Simultaneous kidney-pancreas transplant (SPK) recipients have a higher rate of acute organ rejection than do recipients of a kidney-alone transplant. The etiology of this increased number of rejection episodes is unknown. Cyclosporine (CsA) monitoring in SPK recipients is an important tool in the care of these patients. Many centers use the monoclonal fluorescence polarization immunoassay (mFPIA) to monitor CsA levels in this group of organ recipients. The reported specificity of the mFPIA for the CsA parent compound has varied in several studies but has not been systematically studied in recipients of an SPK transplant. Twelve recipients of an SPK transplant from 1 month to 3 months after surgery had serial simultaneous whole blood high-performance liquid chromatography (HPLC) and mFPIA CsA concentrations evaluated. A control group of 15 nondiabetic kidney-alone recipients underwent a similar evaluation. The average mFPIA/HPLC ratio in recipients of an SPK was 1.71 +/- 0.05 (r = 0.94), whereas it was 1.56 +/- 0.03 (r = 0.98) in the kidney-alone group (p > 0.01). Interpatient variability (range, 1.41 to 2.13) was very high in the SPK group, whereas intrapatient variability was lower. Seven patients had AUC profiles. The average AUC mFPIA/HPLC ratio was not significantly different from each patient's respective trough ratios. Our study suggests that the mFPIA overestimates CsA parent compound to a greater extent in SPK recipients than in kidney-alone recipients. In addition, the large interpatient variability in the specificity of the mFPIA makes assessing individual patient's levels problematic.

Adult↗
PubMed1995

Direct evidence using in situ polymerase chain reaction that the endothelial cell and T-lymphocyte harbor latent murine cytomegalovirus.

The latent viral genome, harbored indefinitely, threatens reactivation from its remote location. Although polymerase chain reaction (PCR) has detected the organs responsible for latency, it is not known whether latent cytomegalovirus (CMV) infection is maintained within organ-specific cells or ubiquitous elements such as macrophages, endothelial cells, or perhaps others. PCR lacks correlation with tissue structure. However, PCR-based in situ hybridization maintains cellular architecture while allowing the identification of the latently infected cells. Murine CMV (MCMV) nucleic acid sequences in organs of latently infected Balb/C mice were amplified by PCR incorporating digoxigenin-11-dUTP, holding the product DNA in situ (appropriate controls analyzed in parallel). Product DNA was then hybridized in situ with a biotinylated oligonucleotide probe for detection via streptavidin-alkaline phosphatase and light microscopy. Immunohistochemistry verified the positive cell types. Using this technique, we have shown directly in multiple organs of latently infected Balb/C mice including kidney (5/5), liver (5/5), and spleen (5/5) that the endothelial cell and/or T-lymphocyte harbor latent MCMV, whereas in uninfected animals, MCMV DNA was not detected. PCR-based in situ hybridization allows detection of the specific cell(s) harboring latent MCMV DNA while allowing conservation of cellular architecture.

Animals↗
PubMed1994

Effect of 15-deoxyspergualin on immediate function and long-term survival of transplanted islets in murine recipients of a marginal islet mass.

15-Deoxyspergualin (DSG), a macrophage immunomodulatory agent, was used as a probe in a murine model of islet transplantation to examine 1) the significance of the nonspecific, macrophage-mediated effector arm of beta-cell injury in recipients of a marginal mass of isologous islets by analyzing the duration of temporary posttransplant hyperglycemia, a parameter of immediate beta-cell function; and 2) whether long-term (> 100 days) functional survival could be achieved in recipients of a marginal mass of allogeneic islets. A dose-response study of the number of islets required to ameliorate diabetes showed that 150 isologous islets per recipient resulted in a 75% incidence of cure at a mean of 39.2 +/- 5.8 days posttransplant. DSG-treated (0.625 mg.kg-1.day-1 intraperitoneally) recipients of isologous islets demonstrated a significant (P < 0.01) reduction in the duration of temporary posttransplant hyperglycemia (16.8 +/- 3.2 vs. 39.2 +/- 5.8 days), and DSG-treated recipients of allogeneic islets demonstrated a significant (P < 0.03) improvement in the rate of achieving long-term functional survival (75 vs. 22% in untreated control animals). Finally, identical rates of islet engraftment were found among control animals and DSG-treated animals by measurement of tissue insulin content in transplanted specimens. The results are consistent with the hypothesis that DSG alters the duration of temporary posttransplant hyperglycemia and extends long-term functional survival in murine recipients of a marginal mass of islets, not by affecting the efficiency of islet engraftment, but by suppression of the inhibitory effects on beta-cell function by nonspecific, macrophage mediators.

Animals↗
PubMed1993

En bloc kidney and whole pancreaticoduodenal transplantation with bladder drainage in the rat: microsurgical technique and outcome.

A microsurgical technique for en bloc kidney and whole pancreaticoduodenal transplantation with bladder drainage employing triple vascular anastomoses without the need for a vascular cuff is described. Nineteen combined isografts were performed using this technique in inbred male Lewis (RT1:I) rats with streptozotocin-induced diabetes. Six recipients died within 1 month from early complications (two from uremia, two from pancreatitis, one from bleeding, one from peritonitis); the other 13 survived more than 1 month after transplantation with both the pancreas and kidney grafts functioning. Four of the 13 rats died after 1 month (one from uremia secondary to an obstructed ureter, one from unexplained uremia, one from peritonitis after a biopsy, and one of unknown causes). The pancreas isografts of two animals were excised at 1 and 3 months to confirm dependence on the graft; both animals became hyperglycemic after graft pancreatectomy and had immediate declines of urine amylase activity to normal. One animal was sacrificed at 3 months to determine the insulin content of its native and transplanted pancreas; insulin was very low in the former and normal in the latter. The remaining rats survived with both grafts functioning for at least 6 months (normoglycemic, high urinary amylase levels, normal or near-normal plasma creatinine concentrations), before being sacrificed within the context of other experiments and for histological observations. Both the kidney and pancreas isografts were well preserved microscopically.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1992

Septate gallbladder with cholelithiasis: a cause of chronic abdominal pain in a 6-year-old child.

This report describes the case of a 6-year-old girl with septate gallbladder and cholelithiasis without cholecystitis, an uncommon condition associated with chronic abdominal pain. The absence of smooth muscle components within the gallbladder septae supports an embryogenic abnormality that may have occurred early during the maturation of the gallbladder lumen. In concert with other predisposing factors, the septa may have induced gallstones and, thus, the patient's symptoms. Although rare, gallbladder abnormalities may cause abdominal pain in children and should be included in the differential diagnosis. Early ultrasound should be obtained as part of a workup if gallbladder abnormalities are suspected. Elective cholecystectomy is curative.

Abdominal Pain↗
PubMed1992

Prolongation of canine islet allograft survival by 15-deoxyspergualin.

Previously we have shown that nonsteroidal, multimodal immunosuppression consisting of cyclosporine (CsA), azathioprine (AZA), and RBC-absorbed goat anti-dog lymphoblast globulin (ALG), at doses considered tolerable in humans, results in limited canine islet allograft survival. Regimens including the diabetogenic agent prednisone are even less successful. In our search for an immunosuppressive regimen that could be applied to human islet transplantation, we tested the effect of 15-deoxyspergualin (DSG) in a canine model. Animals received either CsA, 20 mg/kg/day; AZA, 2.5 mg/kg/day; and ALG, 20 mg/kg/day x 14 days (Group I) or CsA, AZA, ALG at the same doses with the addition of low dose DSG, 0.5 mg/kg/day (Group II). Trough CsA levels by high pressure liquid chromatography ranged in both groups between 100 and 200 micrograms/liter. Rejection of the islets was diagnosed when serum glucose remained greater than 200 mg/dl for 3 consecutive days. There was no significant difference in the number of islets per kilogram of body weight of recipient transplanted in Group I and Group II (5754 +/- 2544 islets/kg versus 7953 +/- 3440 islets/kg, respectively). Animals receiving ALG, CsA, and AZA alone achieved a median islet allograft survival of 4 days, with a mean of 10.8 days. However, with the addition of low-dose DSG, median islet allograft survival was improved to 22 days, with a mean of 32.4 days (P = 0.012, Mann-Whitney test). We conclude that the addition of low-dose DSG to an ALG induction, cyclosporine-based immunosuppressive regimen enhances canine islet allograft survival and has potential for application in clinical islet allotransplantation.

Animals↗