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Biomedical subjects

T Moritz

Publications and source records attributed to T Moritz.

At least 55 records · Page 3Linked to original sources
PubMed1995

Retrovirus-mediated expression of a DNA repair protein in bone marrow protects hematopoietic cells from nitrosourea-induced toxicity in vitro and in vivo.

Severe and delayed myelosuppression is a major side effect encountered with the clinical use of nitrosourea-type chemotherapeutic drugs. The DNA repair protein O6-methylguanine DNA methyltransferase (MGMT) has been shown to repair nitrosourea-induced DNA damage. We therefore investigated the effect of expressing MGMT in hematopoietic cells (via retrovirus-mediated gene transfer) on nitrosourea-induced toxicity. A retroviral vector (N2/ZipPGK-MGMT) expressing the human MGMT cDNA from the phosphoglycerate kinase promoter was constructed. Infection of murine bone marrow with the N2/ZipPGK-MGMT retrovirus significantly increased the survival of murine bone marrow-committed progenitor cells following in vitro exposure to N-N'-bis(2-chloroethyl)-N-nitrosourea (BCNU, carmustine). MGMT gene transfer also protected murine hematopoietic cells in vivo in a murine model of BCNU-induced myelosuppression. The infusion of 4-6 x 10(6) N2/ZipPGK-MGMT-transduced bone marrow cells into mice every 2 weeks significantly increased peripheral leukocyte counts, platelet counts, and hematocrits compared to infusions of mock-infected bone marrow cells. In addition, bone marrow-committed progenitor cells from some recipient animals demonstrated increased resistance to BCNU in vitro when analyzed 2.5 months after initial treatment. The integration of the N2/ZipPGK-MGMT provirus in the spleen DNA from these animals correlated with committed progenitor cell resistance to BCNU. These data suggest that MGMT expression in hematopoietic progenitor and precursor cells protects against nitrosourea-induced toxicity and that gene transfer may prove useful in attempts to reduce nitrosourea-induced myelosuppression in the clinical setting.

3T3 Cells↗
PubMed1995

Use of cumulative meta-analysis in the design, monitoring, and final analysis of a clinical trial: a case study.

From 1983 to 1987, the Department of Veterans Affairs (DVA) Cooperative Studies Program (CSP) conducted a multicenter clinical trial (CSP #207) to determine whether four different antiplatelet regimens compared to placebo could prevent the occlusion of grafts following coronary artery bypass surgery. The study showed that all of the active regimens tended to be better than placebo and that the three regimens containing aspirin were statistically significantly better. A cumulative meta-analysis of 12 trials performed shortly before the end of CSP #207 raised the issue as to whether the meta-analysis, if done earlier, would have changed the conduct of the trial. At the start of the planning period, one trail of size n = 37 had been published with a nonsignificant odds ratio (OR) of 0.74 (95% CI: 0.18, 3.12). At the time that CSP # 207 was approved by the DVA Cooperative Studies Evaluation Committee, two trials had been published (cumulative n = 150, OR = 0.44, 95% CI 0.19, 0.99). At the time patient intake started, five trials showed cumulative n = 769, OR = 0.42, 95% CI = 0.26, 0.68. Although the first 6-month CSP #207 progress report showed no treatment effect, by the time of the 12-month review by the Data Monitoring Board (DMB) a trend was developing in favor of active treatment. If the results of the meta-analysis had been available to the DMB at that time, conceivably the Board would have recommended stopping the placebo arm because of a convincing treatment effect based on the totality of the evidence. Cumulative meta-analysis could be useful as an adjunct in the planning, conduct, and final analysis of a clinical trial. It could also be used as one piece of evidence in the monitoring of the ongoing phase of a trial.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1995

Polymorphism at the P450IIE1 locus is not associated with alcoholic liver disease in Caucasian men.

Because alcoholic hepatitis and cirrhosis, well-known complications of alcohol abuse, do not occur in all alcoholics, genetic factors such as differences in alcohol-metabolizing enzymes may play a role in the development of alcoholic liver disease. Cytochrome P450IIE1 catalyzes the oxidation of ethanol, producing acetaldehyde and free radicals capable of reacting with and peroxidizing cell membranes. Polymorphisms have been identified in the 5'-flanking region of the P450IIE1 gene that may alter the transcriptional activity of the gene. In this study, we analyzed the P450IIE1 genotypes at the polymorphic PstI and RsaI restriction enzyme sites in 53 Caucasians with severe alcoholic liver disease to determine if there is an association between these polymorphisms and alcoholic liver disease. Subjects that tested positive for the hepatitis C virus were eliminated from the study. To identify the type A (homozygous for the c1 gene), type B (heterozygous for the c1 and c2 genes), and type C (homozygous for the c2 gene) genotypes at the P450IIE1 locus, DNA encompassing the polymorphisms was amplified by polymerase chain reaction, slot-blotted, and probed with allele-specific oligonucleotides. Allele frequencies for the c1 allele were 0.95 for alcoholics with severe liver disease, 0.95 for alcoholics without liver disease, and 0.98 for the general population. No differences in allele frequencies between alcoholic patients with severe liver disease and alcoholics without liver disease were observed.

Adult↗
PubMed1995

Relationship of protein calorie malnutrition to alcoholic liver disease: a reexamination of data from two Veterans Administration Cooperative Studies.

The relationship of protein calorie malnutrition (PCM) to alcoholic liver disease was studied in 666 patients enrolled in two Veterans Administration Cooperative Studies. Some findings of malnutrition could be detected early in 62% of the comparison patients (43 subjects who were alcoholic, but had not yet developed clinical or laboratory evidence of liver injury). In those who had progressed to the stage of liver injury sufficient to manifest clinical jaundice (536 patients), some findings of malnutrition were present in every patient (100%). The degree of malnutrition correlated closely with the development of all the serious complications of the liver disease (ascites, encephalopathy, and hepatorenal syndrome), as well as the overall mortality. The degree of malnutrition was also important in predicting response to some forms of treatment. When prednisolone, a catabolic adrenal steroid, was used, efficacy was independent of the level of malnutrition. However, a relationship was observed with the severity of the liver injury [quantified by the level of jaundice and coagulopathy, i.e., Maddrey's discriminant function (DF(Maddrey)]. For prednisolone, the response was seen only when the DF was 81-100 reducing mortality 45% When oxandrolone, an androgenic anabolic steroid treatment was given, efficacy was observed only in those with moderate malnutrition (PCM score 60-79% of normal) and maximized with adequate caloric intake reducing mortality 86%. To simplify the method of calculating the PCM score for predicting response to anabolic therapy, a multiple logistic regression model was developed from the parameters used to assess nutritional status: DF(PCM) = 0.098 (peripheral blood lymphocytes) + 0.078 (creatinine height index).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Bromocriptine treatment of nonfluent aphasia.

Using a double-blind, placebo-controlled, crossover design, we studied the effect of bromocriptine (15 mg daily) in 20 men with chronic nonfluent aphasia. The study was conducted over a 28-week period in two phases. In phase I, the patients received either bromocriptine or placebo; in phase II the treatments were crossed over. We evaluated each patient's language and nonverbal cognitive skills at the beginning and end of each phase and 6 weeks after completion of phase II. When compared with placebo treatment, bromocriptine did not significantly improve the patient's speech fluency, language content, overall degree of aphasia severity, or nonverbal cognitive abilities. Based on these results, bromocriptine is not recommended as monotherapy for the treatment of chronic nonfluent aphasia.

Adult↗
PubMed1994

Increased survival and multilineage hematopoietic protection from delayed and severe myelosuppressive effects of a nitrosourea with recombinant interleukin-11.

The chloroethylnitrosoureas, such as 1,3-bis(2-chloroethyl)-1-nitrosourea, are alkylating agents which are thought to exert antitumor activity by initiating lethal DNA interstrand cross-links. Although nitrosoureas are among the most active agents against childhood and adult gliomas, the utility of this class of agents has been limited by severe and cumulative myelosuppression, which can be fatal. Nitrosourea-induced myelosuppression in humans is delayed and may continue after withdrawal of the agent. We have developed a murine model which mimics the delayed and cumulative myelosuppression seen in humans receiving nitrosoureas. In this model, we demonstrate that interleukin-11, a stromal-derived hematopoietic growth factor with pleiotropic effects in a number of preclinical ablation models, markedly diminishes nitrosourea-induced pancytopenia and leads to a significant reduction in chemotherapy-related mortality. These data suggest that interleukin-11 could allow significant dose intensification in the treatment of tumors which are nitrosourea sensitive.

Animals↗
PubMed1994

Soluble HLA class I and beta-2-microglobulin plasma concentrations during interferon treatment of chronic myelogenous leukemia.

Soluble class I molecules (sHLA-ABC) were measured by an enzyme-linked immunosorbent assay (ELISA) in plasma samples of 13 patients with chronic-phase Ph1-positive chronic myelogenous leukemia (CML). The patients were treated once daily with interferon (IFN) s.c. at a dosage of 4 x 10(6) IU/m2 IFN-alpha-2b or in combination with 50 micrograms IFN-gamma. Measurements were performed before 2, 4, 6, 8, 24, 48, and 72 h after the start of treatment and thereafter every 2-4 weeks. Baseline sHLA-ABC levels were within normal limits (mean 22.1 +/- 8.8 mg/l). An initial decrease of sHLA-ABC (mean 3.2 +/- 2.7 mg/l) was seen in all patients during the first 2-8 h of IFN treatment. Thereafter, sHLA-ABC levels increased steadily reaching maximum values within 2-5 weeks. The overall increase was 12.7 +/- 12.4 mg/l. During the following 2-4 months of IFN treatment sHLA-ABC decreased to near baseline levels in 12 of 13 patients. No difference was detected between IFN-alpha and IFN-alpha plus IFN-gamma treatment. beta 2-Microglobulin values were measured in 8 patients and were found to be correlated to sHLA-ABC concentrations (r = 0.48).

Adult↗
PubMed1994

Long-term graft patency (3 years) after coronary artery surgery. Effects of aspirin: results of a VA Cooperative study.

BACKGROUND: The long-term success of coronary bypass surgery is dependent on graft patency after surgery. This trial was designed to determine if aspirin improved saphenous vein graft or internal mammary artery (IMA) graft patency between 1 and 3 years after coronary artery bypass grafting (CABG). METHODS AND RESULTS: After receiving aspirin 325 mg/d for 1 year after CABG and undergoing a 1-year postoperative cardiac catheterization, patients were randomized to receive either aspirin (325 mg) or placebo for 2 additional years. Angiography was performed 3 years after surgery to determine the primary end point-saphenous vein graft patency in 288 patients and IMA graft patency in 167 patients. At 3 years after CABG, the saphenous vein graft occlusion rate was 17.0% (62 of 365) for patients treated with aspirin compared with 19.7% (74 of 376) for those who received placebo (P = .404). For saphenous vein grafts that were patent at 1 year, the occlusion rate at 3 years was 4.8% (15 of 313) for patients treated with aspirin compared with 4.2% (13 of 310) for patients who received placebo (P = .757). At 3 years, the IMA graft occlusion rate was 10.3% (8 of 78) for patients treated with aspirin compared with 7.9% (7 of 89) for patients who received placebo (P = .594). For IMA grafts that were patent at 1 year, the occlusion rate was 4.3% (3 of 70) for patients treated with aspirin compared with 2.5% (2 of 81) for patients who received placebo (P = .541). CONCLUSIONS: These data suggest that aspirin treatment does not improve saphenous vein graft or IMA graft patency between 1 and 3 years after CABG.

Aspirin↗
PubMed1994

Bone marrow extracellular matrix molecules improve gene transfer into human hematopoietic cells via retroviral vectors.

Direct contact between hematopoietic cells and viral packaging cell lines or other sources of stroma has been shown to increase the efficiency of retroviral-mediated gene transfer into these target cells compared with infection with viral supernatant. We have investigated the role of defined bone marrow extracellular matrix molecules (ECM) in this phenomenon. Here we report that infection of cells adhering to the carboxy-terminal 30/35-kD fragment of the fibronectin molecule (30/35 FN), which contains the alternatively spliced CS-1 cell adhesion domain, significantly increases gene transfer into hematopoietic cells. Two retroviral vectors differing in recombinant viral titer were used. Gene transfer into committed progenitor cells and long-term culture-initiating cells, an in vitro assay for human stem cells, was significantly increased when the cells were infected while adherent to 30/35 FN-coated plates compared with cells infected on BSA-coated control plates or plates coated with other bone marrow ECM molecules. Although gene transfer into committed progenitor cells and to a lesser degree into long-term culture-initiating cells was increased on intact fibronectin as well, increased gene transfer efficiency into hematopoietic cells on 30/35 FN was dependent on CS-1 sequence since infection on a similar FN fragment lacking CS-1 (42 FN) was suboptimal. 30/35 FN has previously been shown by our laboratory and other investigators to mediate adhesion of primitive murine and human hematopoietic stem cells to the hematopoietic microenvironment. Additional studies showed that neither soluble 30/35 FN nor nonspecific binding of hematopoietic cells to poly-L-lysine-coated plates had any appreciable effect on the infection efficiency of these cells. Our findings indicate that hematopoietic stem cell adhesion to specific ECM molecules alters retroviral infection efficiency. These findings should aid in the design of gene transfer protocols using hematopoietic progenitor and stem cells for somatic gene therapy.

Adult↗
PubMed1994

Umbilical cord blood stem cells as targets for genetic modification: new therapeutic approaches to somatic gene therapy.

Human umbilical cord blood is an abundant source of long term repopulating stem cells and therefore we investigated the utilization of these cells as targets for genetic manipulation directed towards human gene therapy. Using two different retroviral vectors, one which transfers the neomycin resistance gene and the other which transfers therapeutically relevant adenosine deaminase gene, we have demonstrated increased gene transfer efficiency into committed progenitor cells (CPCs) and long term culture-initiating cells (LTC-IC) derived from cord blood versus adult bone marrow. We further identified a chymotryptic fragment of the extracellular matrix molecule fibronectin (FN 30/35), to which primitive hematopoietic cells adhere. Gene transfer efficiency into hematopoietic cells adherent to FN 30/35 is significantly increased when compared to infection on bovine serum albumin-coated control plates. Utilization of this fragment allowed retroviral mediated gene transfer into cord blood derived CPCs and LTC-ICs with high efficiencies, similar to that observed after coculture of hematopoietic cells on virus producer cells. These data imply cord blood may be a promising source for efficient gene delivery to the human hematopoietic system, and the utilization of the FN 30/35 fibronectin molecule may provide a clinically applicable protocol to achieve this aim.

Adenosine Deaminase↗
PubMed1994

Gene transfer into the hematopoietic system.

Efficient transfer of heterologous genes into long-term reconstituting stem cells remains difficult to achieve in large animal models and humans. Long-term expression of introduced gene sequences in hematopoietic cells after gene transfer and bone marrow transplantation procedures is usually seen in less than 5% of cells. Retroviral vectors remain the standard tool for this technology, but these vectors have distinct disadvantages, such as the requirement for cycling target cells, random integration into the infected cell genome, and problems with long-term gene expression in long-term reconstituting stem cells. Novel retroviral vectors and producer cell lines that may address some of these problems have been constructed. In addition, modifications of the retroviral infection protocol and the use of alternative stem cell sources such as cord blood or mobilized peripheral blood cells have been tested with some promise. Recent data suggest that adeno-associated virus-based vector might prove an alternative to retroviral vectors in some cases.

Dependovirus↗
PubMed1993

Long-term in vivo expression of a murine adenosine deaminase gene in rhesus monkey hematopoietic cells of multiple lineages after retroviral mediated gene transfer into CD34+ bone marrow cells.

Retroviral mediated gene transfer into stem cells has been proposed as therapy for many inherited hematopoietic diseases. Deficiency of the enzyme adenosine deaminase (ADA) results in depletion of T lymphocytes, causing severe combined immunodeficiency syndrome (SCIDS). In this report, we describe retroviral mediated gene transfer of a murine ADA cDNA into Rhesus monkey hematopoietic stem cells. Immunoselected CD34+ bone marrow cells were exposed to medium containing the ADA retrovirus during culture on a stromal cell line engineered to express the transmembrane form of stem cell factor. After infusion of autologous, transduced cells into irradiated recipients, gene transfer was observed in all three monkeys. The ADA provirus was detected in 2% of circulating granulocytes and T cells from 100 days post-transplantation to longer than 1 year and in B cells from 250 days post-transplantation and beyond. Mouse ADA activity was detected in peripheral blood cells at approximately 3% the activity of monkey ADA. Thus, we have shown gene transfer into repopulating cells that contribute to all hematopoietic lineages with persistent gene expression. These data provide support for the use of stem cell targeted gene transfer for therapy of ADA deficiency.

Adenosine Deaminase↗
PubMed1993

Human cord blood cells as targets for gene transfer: potential use in genetic therapies of severe combined immunodeficiency disease.

Human cord blood (CB) contains large numbers of both committed and primitive hematopoietic progenitor cells and has been shown to have the capacity to reconstitute the lympho-hematopoietic system in transplant protocols. To investigate the potential usefulness of CB stem and progenitor cell populations to deliver new genetic material into the blood and immune systems, we have transduced these cells using retroviral technology and compared the efficiency of gene transfer into CB cells with normal adult human bone marrow cells using a variety of infection protocols. Using two retroviral vectors which differ significantly in both recombinant viral titers and vector design, low density CB or adult bone marrow (ABM) cells were infected, and committed progenitor and more primitive hematopoietic cells were analyzed for gene expression by G418 drug resistance (G418r) of neophosphotransferase and protein analysis for murine adenosine deaminase (mADA). Standard methylcellulose progenitor assays were used to quantitate transduction efficiency of committed progenitor cells, and the long term culture-initiating cell (LTC-IC) assay was used to quantitate transduction efficiency of more primitive cells. Our results indicate that CB cells were more efficiently transduced via retroviral-mediated gene transfer as compared with ABM-derived cells. In addition, stable expression of the introduced gene sequences, including the ADA cDNA, was demonstrated in the progeny of infected LTC-ICs after 5 wk in long-term marrow cultures. Expression of the introduced ADA cDNA was higher than the endogenous human ADA gene in the LTC-IC-derived colonies examined. These studies demonstrate that CB progenitor and stem cells can be efficiently infected using retroviral vectors and suggest that CB cells may provide a suitable target population in gene transfer protocols for some genetic diseases.

Adenosine Deaminase↗
PubMed1993

Relevance of anti-HCV reactivity in patients with alcoholic hepatitis. VA cooperative Study Group #275.

From 8 Department of Veterans Affairs Medical Centers, 296 patients with varying degrees of alcoholic liver disease were tested for hepatitis C (HCV) infection using an EIA and RIBA 2. A high frequency of positive response was observed with 13.9% reactive to both and an additional 4.4% positive only to RIBA 2 (total 18.3%). An evaluation of known risk factors (injection drug use and prior blood transfusions) failed to account for the mode of transmission in 42.6% of the HCV+ patients. The clinical severity of the liver disease and degree of liver pathology were nearly identical in HCV+ vs. HCV- patients. However, the process was accelerated in the HCV+ patients occurring at a 12.8% younger age (p < 0.0001) with a 43% increase in ALT (p = 0.05). The most striking differences were observed in immune parameters. In peripheral blood, total lymphocyte counts were increased 20% (p = 0.01) accompanied by a 56% increase in B cells (p = 0.01) and a 35% elevation of IgG levels (p = 0.0001) in HCV+ patients. T cell changes consisted of a 50% increase in CD8 cells (p = 0.047). However, lymphocyte infiltration into liver was not significantly different (HCV+ vs. HCV-) for any of the subsets studied (CD4, CD8, B cells, NK cells). The combined presence of HCV and alcohol injury did not significantly increase mortality but did significantly increase the number of hospitalizations from 2.4 to 4.0 per year (p = 0.0005).

Hepacivirus↗
PubMed1993

Once-daily versus thrice-daily dosing of netilmicin in combination with beta-lactam antibiotics as empirical therapy for febrile neutropenic patients.

In a prospective, randomized trial, netilmicin given once daily (OD) was compared in terms of efficacy and safety with the conventional 8-hourly dosing regimen (TD), both in combination with a broad spectrum beta-lactam, as initial empirical therapy for febrile neutropenic patients; the total daily dosage of netilmicin in each group was 6 mg/kg body weight. Twenty-nine of the 116 (25%) evaluable patients had microbiologically documented septicaemia, most of which were caused by Gram-positive bacteria, 41 (35%) had microbiologically documented infection without bacteraemia and 46 (40%) had possible infection. Highest peak serum concentrations of netilmicin in the OD group were significantly higher and trough serum concentrations significantly lower than in the TD group. A multivariate analysis revealed that neither the dosage regimen nor the peak serum concentration of netilmicin were determinants of a favourable outcome. The response rates of both groups to the initial treatment regimens were comparable and increased similarly following modification of the initial therapy. Response rates were particularly poor in patients with lower respiratory tract infection and in those who remained neutropenic throughout the course of treatment. The incidence of nephrotoxicity was low and did not differ significantly between groups. Once-daily dosing of netilmicin appears to be as effective and as safe as thrice-daily dosing, but is unlikely to further improve the response of febrile neutropenic patients to empirical therapy.

Anemia, Aplastic↗
PubMed1993

Impact of interferon alpha-induced cytogenetic improvement on survival in chronic myelogenous leukaemia.

The objective of this study was to investigate the prognostic impact of the reduction of Philadelphia chromosome (Ph) positive metaphases by treatment of chronic myelogenous leukaemia (CML) with interferon (IFN) alpha. Therefore, we evaluated the outcome of patients with previously untreated chronic phase Ph-positive CML, enrolled from 1984 to 1990 into two consecutive IFN trials at our institution. Of a total of 71 patients, 62 (87%) were evaluable for cytogenetic response. No cytogenetic improvement was seen in 16 patients (23%), 28 patients (38%) had a decrease in Ph-positive bone marrow metaphases to levels ranging from 35% to 95%, and nine patients (13%) to levels between 5% and 34%. In nine patients (13%), Ph-positive metaphases were no longer detectable. After a median follow-up period of 33 months, the projected 5-year survival is 55% for the 62 patients evaluable for cytogenetic response. In this patient population there was no significant difference in the survival probability according to patients' risk status as defined by the Sokal score. Categorization according to the extent of Ph reduction, however, allowed three groups with significantly different prognoses to be identified. Patients achieving a Ph reduction to less than 35% were found to constitute a low risk group with a median survival not yet known and a projected 5-year survival of 90%. The 5-year survival rate was 55% for patients with a Ph reduction to levels between 35% and 95%, and less than 10% for those without any cytogenetic improvement. Thus, this study demonstrates that cytogenetic improvement on IFN treatment is an important prognostic factor for survival.

Adolescent↗
PubMed1993

Long-term treatment of chronic myelogenous leukemia with different interferons: results from three studies.

131 patients with Philadelphia (Ph') chromosome positive chronic myelogenous leukemia (CML) were treated with interferon (IFN) alpha or a combination of IFN alpha and IFN gamma. In study, 1, 13 not pretreated and 41 pretreated patients, 48 in chronic phase disease, 6 in accelerated phase, received 4 x 10(6) U/m2 IFN alfa-2b initially. After achievement of hematologic remission, the individually minimum effective dose was used for maintenance. There was no response in acute phase disease. Of the 48 patients with chronic phase disease, 22 achieved a hematologic remission (HR), 13 a partial HR (PHR), and 13 did not respond (NR) to IFN. No major cytogenetic response occurred in these patients, but two patients achieved a major molecular response in Southern blots, whereas PCR tests were positive. In a further randomized study, CML patients without prior therapy were treated initially with 4 x 10(6) U/m2 IFN alpha alone (arm A) or in combination with 50 micrograms IFN gamma (arm B). For maintenance, the maximum tolerable dose of IFN alpha was given (up to 10 x 10(6) U/day). Thirteen patients in arm A (54%) and 14 (56%) patients in arm B achieved a HR, 7 patients (29%) in arm A and 6 patients (24%) in arm B a PHR. No response could be induced in 4 patients (17%) of arm A and 5 patients (21%) of arm B. Major cytogenetic responses were observed in 5 (20%) patients of arm A and 5 patients (20%) of arm B. Major molecular responses were observed in 3 patients of arm A and 5 patients of arm B.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗