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Biomedical subjects

D Roth

Publications and source records attributed to D Roth.

At least 73 records · Page 4Linked to original sources

Unexpected augmentation of mycophenolic acid pharmacokinetics in renal transplant patients receiving tacrolimus and mycophenolate mofetil in combination therapy, and analogous in vitro findings.

Mycophenolate mofetil (MMF) a potent immunosuppressive agent, has recently been approved for clinical use (CellCept) in renal transplant patients in combination with cyclosporine (CsA). With the expanded use of tacrolimus (Prograf) as well in renal transplant patients, there is a lack of pharmacokinetic studies clarifying drug interactions between the three agents. A pharmacokinetic study was performed on 18 stable renal transplant patients receiving MMF and tacrolimus together, and four control groups, one receiving tacrolimus alone, two receiving CsA, in combination with MMF (1.0 or 1.5 g bid), and one receiving CsA microemulsion (Neoral). Area-under-the-curve values were calculated for each drug to assess if there was a reciprocal effect on the respective bioavailability of each. In vitro, the immunosuppressive effect of trough level plasma from each patient group was studied using mixed lymphocyte culture (MLC), as well as MLC reactions spiked with various combinations of each drug. There was a minimal effect of MMF on tacrolimus pharmacokinetics. However, patients receiving tacrolimus and MMF displayed significantly higher levels (Cmin and area under the curve) of mycophenolic acid (MPA) than those receiving CsA (Sandimmune or Neoral) and the same dose of MMF (50.2 +/- 16.5 vs 32.1 +/- 16.7 micrograms h/ml AUC, p < 0.02). Equivalent MPA levels could be attained in patients receiving CsA if the MMF dose was increased by 50% (1.5 g bid). There were also significantly lower levels of the glucuronide metabolite of MPA (MPAG) (755 +/- 280 vs 1230 +/- 250 micrograms h/ml AUC, p = 0.02), suggesting a specific inhibition (either direct or indirect) of the conversion of MPA to MPAG in tacrolimus patients, as opposed to those receiving CsA. For each drug combination, there was a positive correlation between the plasma immunosuppressive effect seen in MLC assays and the MMF dose. In addition, trough plasma from patients receiving tacrolimus and MMF was significantly more MLC inhibitory than from those receiving CsA or CsA microemulsion and equivalent-dose MMF. Culture media containing MPA and tacrolimus equal to clinical therapeutic trough concentrations (10 ng/ml) were significantly more MLC inhibitory than CsA at equivalent clinical therapeutic trough concentrations (200 ng/ml) with equivalent MPA levels. These studies in renal transplant patients suggest that tacrolimus in combination with MMF may result in a greater degree of immunosuppression than may be anticipated.

Adult↗

Impact of state mental health reform on patterns of service delivery.

Legislation enacted in 1988 in Ohio, aimed at redistributing funding from state hospitals to community support services and prioritizing the funding for treatment of individuals with severe mental disabilities (SMD), raises important questions from a service system perspective. To assess the impact of this reform legislation on Ohio's mental health service delivery system, cluster analyses of community mental health service data were conducted for five yearly samples of approximately 4,000 adults with SMD. An analysis of resulting service patterns demonstrated a decrease in service clusters comprised of individuals receiving little more than medication check-ups and an increase in clusters comprised of individuals receiving combinations of two or more services. Increases were found in most community mental health services; however, in each year, approximately 50% of the sample received few services of any kind, while approximately 10% of the sample received voluminous amounts of highly individualized services.

Adult↗

The immune reactivity role of HCV-induced liver infiltrating lymphocytes in hepatocellular damage.

Liver infiltrating lymphocytes (LIL) were isolated from HCV-positive (+) and HCV-negative (-) end-stage livers. Phenotypic analysis and functional studies using proliferative and lymphocytotoxic assays were performed with the isolated LIL. Two CD3+ lymphocyte populations were found in LIL using FITC anti-CD3 monoclonal antibodies (mAb). One was a bright fluorescence intensity population (as in PBL), and the other dim. We calculated the number of FITC-anti-CD3 mAbs bound per lymphocyte on PBL and LIL and found 80,040 +/- 4628 and 39,615 +/- 3932, respectively. Therefore, HCV+ and HCV- patient PBL contained approximately twice the number of CD3 molecules per cell than patient CD3+ LIL. LIL also contained approximately a threefold higher concentration of TCR alpha beta +, CD4-CD8-, and CD56,16 (NK) cells than the patient PBL. Thus, a major subset of LIL is phenotypically similar to mouse NK1.1+ "intermediate" T cells. LIL freshly isolated from HCV+ livers exhibited weak CTL activity against EBV- or Con A-transformed lymphoblast targets infected with vaccinia-HCV recombinant virus (rHCV) or primary hepatocyte cultured cells. However, after in vitro coculture of LIL with rHCV, these cells developed a strong cytotoxicity for the above targets. In contrast, LIL from HCV- livers were not cytotoxic against the same targets. Histochemical studies (in situ) demonstrated that these hepatocytes express CD95, and stains demonstrated apoptosis. The HCV+ hepatocytes also express class I MHC molecules and ICAM-1. The addition of mAb specific for these adhesion molecules inhibited CML activity. Short-term cultured hepatocytes (targets) from HCV+ and HCV- patients produced low levels of cytokines IL-1 beta, IL-2, IL-6, TNF alpha, and IFN-gamma but a high level of IL-8. It is speculated that LIL expressing reduced numbers of CD3 molecules may even function as immune regulators as proposed for intermediate T cells in mice.

Antibodies, Monoclonal↗

Cognitive impairment in the Amish: a four county survey.

BACKGROUND: The prevalence of probable dementia was determined in a rural, homogeneous community of Amish individuals in the Midwestern USA. The Amish are a genetically isolated group with a low level of formal education (< or = 8 years) and few exposures to modern life, who live in intergenerational setting and have strong social support networks. METHODS: Using community directories, trained interviewers administered the Mini Mental State Examination (MMSE) and a medical history survey to all Amish over 64 years old in a four county area. Individuals with scores < 27 (out of a maximum of 30 points) were given additional neuropsychological tests. Results were reviewed by a neuropsychologist and subjects were classified with regard to probable cognitive impairment. RESULTS: The MMSE scores were inversely related with age and directly with education. The Amish have higher MMSE scores than reported for the general US population. The overall prevalence of probable cognitive impairment for those over 64 years was 6.4%. The prevalence increased with age and lower education and was lowest among married individuals. CONCLUSIONS: The MMSE scores among the Amish were higher than the general population despite their low level of formal education. The lower level of cognitive impairment among the Amish could reflect a lack of inherited susceptibility to dementing diseases, or environmental factors characteristic of their traditional lifestyle. Even among this population with < or = 8 years of formal education, education may protect against cognitive impairment.

Age Distribution↗

Psychiatric collaboration in a paediatric department.

OBJECTIVE: To review the impact of integrating child psychiatry services into a paediatric department. METHOD: Following the arrival of a new head of paediatrics, a mandatory multidisciplinary meeting was set up to review, diagnose and manage selected patients under the care of the paediatricians and/or a child psychiatrist. A prospective audit was undertaken of the patients discussed with a brief review of their outcome. The educational value of the meetings and their overall impact on the department was reviewed. RESULTS: Over an 8-month period 30 patients were discussed in some detail with diagnoses ranging from a psychiatric disorder to a chronic organic illness, each subjected to the deliberations of the multidisciplinary team of the attending paediatrician, resident staff, child psychiatrist/psychologists, nurses, social worker, etc. Recommendations included further assessment by the psychiatric team, or management by the paediatricians with or without guidance of the former, involvement of an outside agency, etc. Such interventions generally had positive outcomes: at times dramatic, although early discharge often resulted in limited goals. There was also an overall increased awareness within the department of the psychological needs of the child and family and the importance of serious physical illness; this awareness is essential in the training of paediatricians and psychiatric staff. CONCLUSION: Closer integration of the two disciplines led to benefits both to the patients and staff. The initiation of a mandatory multidisciplinary meeting facilitated the process, overseen by a psychologically-minded new head of paediatrics. His departure led to a loss of some goals achieved, raising the question as to how such collaboration may be self-generating and ongoing. In addition, the issue of how to deal with those patients with ongoing difficulties not addressed during their limited inpatient stay was unresolved.

Adolescent↗

Post-transplant lymphoproliferative disease in kidney transplant patients in the new immunosuppressive era.

Although the kidney transplant program at this center has been active for the past 18 yr, five out of the seven cases of post-transplant lymphoma in kidney transplant patients were observed over the past 2 yr. During this period, we have shifted from cyclosporine to tacrolimus (FK506 or prograf) for maintenance immunosuppression and for rescue therapy. We have also introduced mycophenolate (RS-61443) and have continued an antibody induction regimen in the immediate postoperative period. FK506 is 50-100 times more potent than cyclosporine. We have reported a decreased incidence of rejection, improved graft survival, and a general optimalization of patient survival with these newer regimens. Nonetheless, five cases of post-transplant lymphoma out of 233 kidney transplants (2.1%) performed during this time period (December 1993 to December 1995) occurred between 3 months to 1 yr after the transplant. Four of the five patients are still alive between 12 and 24 months after the diagnosis of lymphoma was made. All were without evidence of ongoing disease. Three of the five have grafts with excellent function for longer than 18 months after transplantation, while one is marginal and one patient expired on dialysis. The third and fourth patients had severe rejection before the diagnosis of PTLD was made. While the occurrence of five cases of post-transplant lymphoma over a 2 yr period is alarming, this is still within the 2-4% incidence of post-transplant lymphoma that has been reported in the literature in kidney transplant patients. Our results probably reflect the increasing potency of our immunosuppressive protocols but do not show any increase in the aggressiveness of this entity of post-transplant lymphoma during the continued follow up.

Adolescent↗

The use of tacrolimus as induction and maintenance immunosuppression in renal cadaveric transplant recipients over the age of 60.

Renal transplantation is a treatment option that should be considered for the elderly (> or = 60 years old) with end-stage renal disease. Little is known regarding the use of tacrolimus (as induction and maintenance immunosuppression) in this age group. We report the outcome of kidney transplantation in 21 patients aged 60 years or more with tacrolimus. During the past few years in kidney transplant maintenance immunosuppressive regimens, we have revised our standard general protocol from cyclosporine to tacrolimus-based therapy for maintenance immunosuppression and for rescue therapy. We also introduced mycophenolate (RS-61443) while we have continued to use ATGAM/OKT3 as induction regimen in the immediate postoperative period. We treated these renal recipients with tacrolimus and steroids in combination with azathioprine or mycophenolate mofetil without antibody induction. This was well tolerated and not associated with a higher rate of rejection (20%) whereas the potential toxicity of antilymphocyte preparations was avoided.

Administration, Oral↗

Rapid HIV testing and counseling for voluntary testing centers in Africa.

OBJECTIVE: Voluntary HIV testing and counseling (VTC) has been shown to reduce the incidence of HIV in cohabiting couples who now represent the majority of new infections in many African cities. Community and client perceptions of a 1-day voluntary testing and counseling program in Lusaka, Zambia, were assessed, and a rapid HIV-testing algorithm was evaluated for VTC centers. METHODS AND DESIGN: Between May 1995 and June 1996, outreach workers distributed written invitations door to door. The 1-day program was held 6 days/week including weekends. Transport, child care and lunch were provided. Community and client surveys followed in July 1996. RESULTS: Over 3500 couples married for a median of 4-5 years requested testing: 23% were HIV+/+, 57% were HIV-/- and 20% were discordant with one HIV+ and one HIV- partner. Sixty-eight per cent of couples surveyed had made the decision to be tested before attending the 1-day program and 80% had not previously known where to obtain HIV testing. Knowledge that couples could show discordant results rose from 29 before to 88% after pretest counseling. Clients reported high levels of satisfaction with the services and 90 out of 99 (92%) preferred to receive their results the same day. Clients at another center who waited 10 days for their results reported more fear, and 19 out of 31 (61%) would have preferred to get their results the same day. Over 99% of those who attended the program thought active promotion of voluntary HIV testing in the community was a positive thing, as did 90% of those who were invited but did not attend. Sensitivity and specificity of the rapid test algorithm were both 99.4% in this setting. CONCLUSIONS: Active promotion of voluntary HIV testing and counseling in couples is needed to reduce the spread of HIV in high-prevalence areas. The use of rapid, on-site HIV testing allows clients to receive result-specific counseling in a single visit. Ongoing quality control of a subset of samples at an outside laboratory is essential.

Acquired Immunodeficiency Syndrome↗

Evaluation of fluvastatin in the treatment of hypercholesterolemia in renal transplant recipients taking cyclosporine.

Occlusive atherosclerosis is a major cause of morbidity and mortality in renal transplant recipients. Hyperlipidemia associated with the transplanted state may be at least partially responsible for this complication and is therefore an important target of therapy. The 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors are powerful cholesterol-lowering drugs, but their broad use in transplant recipients has been hindered by concerns about interactions with cyclosporine. Cyclosporine interferes with the elimination of these agents, increasing their plasma and tissue levels and predisposing the patient to rhabdomyolysis. Fluvastatin, the first entirely synthetic HMG-CoA reductase inhibitor, possesses a distinct pharmacologic profile, including a shorter half-life and virtually no active circulating metabolites. Therefore, it may interact differently with cyclosporine. The pharmacokinetics and safety of fluvastatin, 20 mg/day, were evaluated in 20 hypercholesterolemic renal transplant recipients also receiving cyclosporine, usually in combination with azathioprine and methylprednisolone, during the 14-week study. Fluvastatin area under the curve, maximum plasma concentration, and time to maximum plasma concentration were minimally increased in these patients, unlike findings reported for lovastatin, pravastatin, and simvastatin. This suggests that metabolism of fluvastatin may be less affected by cyclosporine than that of other reductase inhibitors. Fluvastatin was well tolerated, with no evidence of myopathy, rhabdomyolysis, or ophthalmologic abnormalities. These findings and the significant reductions in total cholesterol and low-density lipoprotein cholesterol levels and the ratio of low-density to high-density lipoproteins achieved in these patients support the broader use of fluvastatin to treat hypercholesterolemia in renal transplant recipients.

Adult↗

The Exocyst is a multiprotein complex required for exocytosis in Saccharomyces cerevisiae.

In the yeast Saccharomyces cerevisiae, the products of at least 15 genes are involved specifically in vesicular transport from the Golgi apparatus to the plasma membrane. Previously, we have shown that three of these genes, SEC6, SEC8 and SEC15, encode components of a multisubunit complex which localizes to the tip of the bud, the predominant site of exocytosis in S. cerevisiae. Mutations in three more of these genes, SEC3, SEC5 and SEC10, were found to disrupt the subunit integrity of the Sec6-Sec8-Sec15 complex, indicating that these genes may encode some of the remaining components of this complex. To examine this possibility, we cloned and sequenced the SEC5 and SEC10 genes, disrupted them, and either epitope tagged them (Sec5p) or prepared polyclonal antisera (Sec10p) to them for co-immunoprecipitation studies. Concurrently, we biochemically purified the remaining unidentified polypeptides of the Sec6-Sec8-Sec15 complex for peptide microsequencing. The genes encoding these components were identified by comparison of predicted amino acid sequences with those obtained from peptide microsequencing of the purified complex components. In addition to Sec6p, Sec8p and Sec15p, the complex contains the proteins encoded by SEC3, SEC5, SEC10 and a novel gene, EXO70. Since these seven proteins function together in a complex required for exocytosis, and not other intracellular trafficking steps, we have named it the Exocyst.

Amino Acid Sequence↗

Pathogenic role of anti-endothelial cell antibodies in vasculitis. An idiotypic experimental model.

Idiotypic manipulation of naive mice has previously been used for induction of systemic autoimmune diseases (e.g., antiphospholipid syndrome, systemic lupus erythematosus, and Wegener's granulomatosis). The aim of this study focused on the utilization of this technique to induce the production of anti-endothelial cells Abs (AECA) and autoimmune vasculitis in a murine model. AECA were derived from a Wegener's granulomatosis patient's plasma. IgG was purified by absorption on a proteinase-3 affinity column resulting in the depletion of anti-neutrophil cytoplasmic Ab activity. The absorbed IgG fraction displayed a high titer of AECA as evidenced by a cyto-ELISA against unfixed human umbilical vein endothelial cells. BALB/c mice were actively immunized with the purified AECA. Three months after a boost injection with the human AECA, mice developed endogenous AECA (AB), but not Abs to proteinase-3, cardiolipin, or DNA. Histologic examination of lungs and kidneys revealed both lymphoid cell infiltration surrounding arterioles and venules; as well as deposition of Igs at the outer part of blood vessel walls. This experimental animal model of vasculitis, a product of our method of idiotypic manipulation, provides the first direct proof for the pathogenicity of AECA.

Animals↗

Destructive allograft fungal arteritis following simultaneous pancreas-kidney transplantation.

Fungal arteritis of the Y graft used to revascularize the whole pancreas graft developed in 2 recipients of simultaneous pancreas-kidney transplant that were performed within 36 hr of each other. The vascular infection became manifest 6-7 days following transplantation. In both patients, the vasculitis culminated in an arterial rupture that required immediate operative intervention. This compromise of the Y grafts contributed to loss of both pancreatic grafts and necessitated vascular reconstruction to reperfuse the lower extremity. To date, both patients continue to experience normal kidney transplant function.

Adult↗