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P Martin

Publications and source records attributed to P Martin.

At least 397 records · Page 22Linked to original sources
PubMed1997

Retrovirus-induced target cell activation in the early phases of infection: the mouse mammary tumor virus model.

Mouse mammary tumor virus (MMTV) infects B lymphocytes and expresses a superantigen on the cell surface after integration of its reverse-transcribed genome. Superantigen-dependent B- and T-cell activation becomes detectable 2 to 3 days after infection. We show here that before this event, B cells undergo a polyclonal activation which does not involve massive proliferation. This first phase of B-cell activation is T cell independent. Moreover, during the first phase of activation, when only a small fraction of B cells is infected by MMTV(SW), viral DNA is detected only in activated B cells. Such a B-cell activation is also seen after injection of murine leukemia virus but not after injection of vaccinia virus, despite the very similar kinetics and intensity of the immune response. Since retroviruses require activated target cells to induce efficient infection, these data suggest that the early polyclonal retrovirus-induced target cell activation might play an important role in the establishment of retroviral infections.

Animals↗
PubMed1997

Factors of nutritional health-seeking behaviors. Findings from the Georgia Centenarian Study.

Health-seeking behaviors are described by Harris and Guten (1979) as any behavior of an individual that promotes, protects, or maintains one's health, regardless of actual or perceived health status. The purpose of this study was to determine if nutritional health-seeking behavior (Bausell, 1986) comprised one or more factors for older adults (N = 256). Participants were in their 60s (n = 90), 80s (n = 91), and 100+ (n = 75). Exploratory factor analysis indicated that nutritional health-seeking behavior items formed two factors: avoid (i.e., avoiding unhealthy nutritional behavior) and seek (i.e., attempting or seeking healthy nutritional behavior). Multiple regression analysis revealed that risk factors for poor nutritional health-seeking behaviors in older adults include advanced age, low economic resources, and male gender. Protective factors included in the personality factors of self-discipline, enthusiasm, sensitivity, and warmth.

Age Factors↗
PubMed1997

Concomitant chemoradiotherapy followed, where feasible, by surgery for cancer of the esophagus.

PURPOSE: To conduct a multicenter phase II study of a concomitant combination of chemotherapy and radiotherapy followed by surgery, where feasible, in patients with nonmetastatic esophageal tumor, stratified on operability at diagnosis. METHODS: Each cycle consisted of fluorouracil (5FU) 800 mg/m2/d by continuous intravenous (IV) infusion on days 1 to 5, cisplatin (CDDP) 50 mg/m2/d IV bolus on days 1 and 8, hydroxyurea (HU) 1.5 or 2 g/d orally on days 8 to 12 and concomitant radiotherapy 20 Gy in 10 fractions over 12 days. All patients were to receive two cycles on days 1 and 22. If feasible, surgery was performed 3 to 6 weeks after cycle two completion. Otherwise, a third cycle was administered. RESULTS: Eighty-eight patients were included between September 1990 and September 1993. Of the 47 operable patients, 41 (87%) underwent surgery and 38 (81%) had a complete resection. No residual primary tumor was found in the surgical specimen in 17 cases (36%), and only microscopic foci in 13 (28%). Two-year overall and disease-free survival probabilities were 51% (95% confidence interval [CI]; 37 to 65) and 43% (95% CI, 28 to 57), respectively. Among the 41 inoperable patients, 12 (29%) became operable. Seven (17%) had complete resection, two incomplete resection, and three exploratory surgery. Two-year overall and disease-free survival probabilities were 29% (95% CI, 15 to 43) and 27% (95% CI, 13 to 40), respectively. Five deaths occurred during chemoradiotherapy, six postoperatively and four in patients with evidence of cancer. Five late complications (one myelopathy) were observed. CONCLUSION: Despite a high histologic response rate in initially operable patients, overall survival was similar to that observed in other preoperative chemoradiation series because of substantial toxicity.

Aged↗
PubMed1997

[Economic impact of bipolar mood disorders].

The implementation of spending control policies to combat rising healthcare costs and public health department deficits in the industrialised countries poses the problem of how to maintain high standards of treatment and ensure quality of life for patients. Only a proper medico-economic evaluation of the various therapeutic strategies available will allow the two sides of this equation to be reconciled; one wonders in fact whether these two sides are indeed contradictory. This is particularly true as regards the treatment of mental illnesses. Because of their chronic status, together with inherent problems of diagnosis and management, bipolar disorders appear at first sight to present a marked impact in economic terms, and are thus highly problematic for health authorities. Budgetary control is far more complex than simple management of scarce resources, since the least expensive therapies are not necessarily the most cost-effective. Nevertheless, data allowing accurate assessment of the costs related to these disorders are rare or non-existent. Furthermore, the impact of a given treatment for bipolar disorders on the quality of life of the patient may have a direct economic bearing if one takes account of additional drug consumption and further social deficit resulting from unsuccessful therapy, as well as of social and family problems related to this type of disorder.

Bipolar Disorder↗
PubMed1997

Use of OKT3 is associated with early and severe recurrence of hepatitis C after liver transplantation.

OBJECTIVE: To determine whether increased immunosuppression is a contributor to poor outcome in hepatitis C-infected orthotopic liver transplant (OLT) recipients, we retrospectively analyzed the consequences of using OKT3 in our program for steroid-resistant rejection (SRR). METHODS: We compared the histological recurrence of HCV in two contemporary cohorts of OLT recipients. Group 1 consisted of HCV-positive patients who received OKT3 for SRR (n = 19). Group 2 (n = 33) consisted of age-, gender-, and initial immunosuppression-matched HCV-positive controls who were treated with at least one steroid pulse for acute cellular rejection but who did not require treatment with OKT3. Liver biopsies were obtained per protocol within the first month and as necessary to evaluate abnormalities in serum liver chemistries. RESULTS: Mean and median follow-up were comparable for the two groups. Recurrence of HCV was diagnosed by histological verification and was documented in 16 of 19 (84.2%) group 1 patients versus 17 of 33 (51.5%) group 2 patients (p = 0.03). The interval to recurrence was significantly shorter in patients who received OKT3 (p = 0.028). Logistic regression identified OKT3 as a significant risk factor for the recurrence of HCV within the first year post-OLT (p = 0.0004). The histological severity score, based on the most recent liver biopsy at long-term follow-up or the explant biopsy if the patient required retransplantation, was significantly higher in group 1. Moreover, cirrhosis was demonstrable in a greater proportion of allografts in patients who had received OKT3 at some point (26.3% vs. 6%, p = 0.028). Long-term follow-up revealed a trend toward higher alanine aminotransferase levels (p = 0.05) and total bilirubin (p = 0.08) in group 1 patients. CONCLUSIONS: Our data suggest that allograft hepatitis in patients with preexisting HCV occurs earlier and with greater severity in patients treated with OKT3 for SRR, compared with age-, gender-, and initial immunosuppression-matched contemporary controls. Treatment of SRR with OKT3 may jeopardize long-term allograft function and survival in HCV-infected recipients by enhancing viral hepatitis recurrence. Clearly, the recognition of recurrent HCV and differentiation from acute cellular rejection remains a crucial issue in managing the OLT recipient with HCV.

Acute Disease↗
PubMed1997

Methotrexate and cyclosporine for graft-vs.-host disease prevention: what length of therapy with cyclosporine?

One hundred three patients with leukemia, aplastic anemia, or myelodysplastic syndrome were treated by marrow transplantation from genotypically HLA-identical siblings (n = 92) or HLA haploidentical family members differing for one HLA antigen on the nonshared haplotype (n = 11). To prevent graft-vs.-host disease (GVHD), they were administered postgrafting immunosuppression with a short course of intermittent methotrexate with daily cyclosporine for no more than 11 days. Customarily, we have given cyclosporine for 180 days after transplant. In the current study, we asked whether cyclosporine could be stopped earlier without affecting the risk of chronic GVHD. By day 60, patients who never had acute GVHD, or whose acute GVHD had resolved, were randomized to have cyclosporine stopped (n = 52) or continued for the usual 180 days (n = 51). Results were analyzed with a median follow-up of 9.3 years after transplant, and showed that patients in whom cyclosporine was discontinued on day 60 had a significantly more rapid onset (p = 0.001), but not a significantly higher overall incidence of chronic GVHD than those in whom the drug was stopped on day 180 (43 vs. 54%; p = 0.26). Transplant-related mortality was comparable among patients without preceding acute GVHD, regardless of when cyclosporine was discontinued (11% for both study arms). However, transplant-related mortality appeared to increase among patients with preceding acute GVHD in whom cyclosporine was stopped by day 60 (38 vs. 17%). Results suggest that cyclosporine can safely be discontinued early in patients who never had evidence of acute GVHD, while those with preceding acute GVHD would benefit from a longer course of the drug. Because of the relatively small sample sizes, these results would best be treated as promising preliminary findings that should be confirmed in larger randomized studies.

Adult↗
PubMed1996

Graft loss following liver transplantation in patients with chronic hepatitis C.

Liver disease due to hepatitis C (HCV) is an increasingly frequent indication for orthotopic liver transplantation (OLT). The aim of the current study was to analyze the causes of graft loss following OLT for chronic hepatitis C and the longterm outcome following retransplantation in a large university program. Between January 1990 and December 1995, 1183 patients underwent primary OLT at our center. In 304 patients, HCV was diagnosed by seropositivity and/or polymerase chain reaction. Fifty-six (18.4%) of these patients underwent retransplantation. The 36 patients retransplanted for primary non-function were excluded from further analysis. The other indications for regrafting (>30 days following primary transplant) included hepatic artery thrombosis (5), chronic rejection (4), severe HCV recurrence (5), and other etiologies (6). The cumulative survival rates for the 248 patients who received 1 OLT (group 1) were 84% after one year and 75% after three years. The corresponding rates for the 20 non-PNF patients who were retransplanted (group 2) were 60% and 43%, respectively (P<.0001). Moreover, logistic regression analysis confirmed that patients in group 2 were more than 4 times likely to die than patients in group 1 (P<.0034; risk ratio, 4.2; 95% confidence interval 1.61 to 11.37). Patients undergoing retransplantation had a high incidence of serious infectious complications leading to mortality. Two additional patients with severe recurrent HCV died awaiting liver retransplantation. Eight of the 304 total patients (2.6%) transplanted for chronic HCV developed graft failure secondary to HCV recurrence and 6 of the 8 were retransplanted; 3 of the 6 patients retransplanted are alive without evidence of histologic recurrence (mean follow-up less than 1 year). In summary, despite the high frequency of recurrent histologic evidence of HCV following primary OLT (70% at 3 years), graft loss attributable solely to HCV is an infrequent finding. Retransplantation per se is a risk factor for a fatal outcome, and the indication for reOLT does not appear to impact ultimate outcome. Serious infectious complications were the leading cause of mortality in patients retransplanted. Furthermore, given the indolent natural history of HCV, longer follow-up is necessary to determine the ultimate rate of graft loss due to HCV recurrence.

Biopsy↗
PubMed1996

Transplantation of allogeneic CD34+ peripheral blood stem cells in patients with advanced hematologic malignancy.

Sixteen patients with advanced hematologic malignancies were transplanted with HLA-identical allogeneic peripheral blood stem cells (PBSCs) that were selected for CD34+ cells by an avidin-biotin immunoadsorption technique. The median age of patients was 48 years (range, 37 to 67). Patients received 12.0 or 13.2 Gy of total body irradiation followed by 120 mg/kg of cyclophosphamide. Normal donors received 16 mg/kg of granulocyte-colony stimulating factor on days 1 to 6 followed by PBSC harvests on days 4 to 7. PBSC harvests were processed each day on a single avidin-blotin column containing an antibody to the CD34 antigen and processed cells were infused without cryopreservation daily for 4 consecutive days. Prophylaxis against graft-versus-host disease (GVHD) consisted of cyclosporine alone for 5 patients and CSA plus methotrexate for 11 patients. A median of 18.64 (6.74 to 34.97) x 10(8) CD34+ cells/kg patient body weight were collected from each donor. A median of 8.96 (2.62 to 17.34) x 10(8) CD34+ cells/kg patient body weight were recovered after avidin-biotin adsorption which represented a median CD34+ cell yield of 53% (18% to 77%) with a median purity of 62% (34% to 82%). There was a reduction in CD3+ cells from a median of 557.26 (227.73 to 677.77) x 106/kg to 0.73 x 10(4)/kg (0.40 to 3.65), in CD4+ cells from 351.72 (194.47 to 520.11) x 10(6)/kg to 0.40 (0.15 to 1.03) x 10(4)/kg and in CD8+ cells from 169.74 (53.34 to 325.83) x 10(6)/ kg to 0.32 (0.12 to 2.71) x 10(4)/kg representing a median 2.8 (2.19 to 3.14) log reduction in T cells. One patient died of infection on day 3 posttransplant and was unevaluable for recovery of neutrophils. The median day to recovery of 500 neutrophils/mL was 15 (8 to 26) in the remaining 15 patients. Six of 16 patients falled to achieve a platelet count of 20,000/mL before death on days 3 to 97 of transplant-related complications. The median day to achieving platelets of 20,000 mL in the remaining 10 patients was 11 (7 to 31). Eight of 16 patients (50%) died between 3 and 97 days posttransplant, 7 of transplant-related causes, and 1 of progressive disease. Grade 2-4 acute GVHD occurred in 12 out of 14 (86%) and grades 3-4 in 6 out of 14 (43%) evaluable patients. Six of 8 evaluable patients developed clinical chronic GVHD and 1 developed subclinical chronic GVHD. Bone marrow and/or peripheral blood chimerism studies in 12 evaluable patients showed 97% to 100% donor type in 11 patients with 1 patient in relapse showing 40% donor cells 60 to 90 days posttransplant. Four of 16 patients (25%) are alive and disease-free 312 to 576 days after transplant. There were no episodes of graft failure or rejection. This study shows that allogeneic transplantation using CD34+ selected PBSC results in prompt and sustained engraftment. CD34+ selection, as employed in this preliminary study, however, resulted in an apparently higher rate of acute and chronic GVHD. However, The sample size is quite small and precludes a more definitive conclusion regarding GVHD.

Adult↗
PubMed1996

Identification of a novel opioid peptide (Tyr-Val-Pro-Phe-Pro) derived from human alpha S1 casein (alpha S1-casomorphin, and alpha S1-casomorphin amide).

A new casomorphin pentapeptide (alpha S1-casomorphin) has been isolated from the sequence of human alpha S1-casein [alpha S1-casein-(158-162)], with the sequence Tyr-Val-Pro-Phe-Pro. This peptide was found to bind with high affinity to all three subtypes of the kappa-opioid receptor (kappa 1-kappa 2). When amidated at the C-terminus, alpha S1-casomorphin amide binds to the delta- and kappa 3-opioid sites. Both alpha S1-casomorphin and its amide inhibit in a dose-dependent and reversible manner the proliferation of T47D human breast cancer cells. This anti-proliferative activity was greater for alpha S1-casomorphin, which was the most potent opioid in inhibiting T47D cell proliferation. In T47D breast cancer cells, other casomorphins have been found to bind to somatostatin receptors in addition to opioid sites. In contrast, alpha S1-casomorphin and its amide do not interact with somatostatin receptors in our system.

Amino Acid Sequence↗
PubMed1996

FK506 in combination with methotrexate for the prevention of graft-versus-host disease after marrow transplantation from matched unrelated donors.

The safety and potential efficacy of FK506 in combination with a short course of methotrexate (MTX) for the prevention of acute graft-versus-host disease (GVHD) after marrow transplantation from HLA-matched unrelated donors was evaluated in a single-arm Phase II study conducted at two centers. Forty-three patients, 15 to 54 (median 41) years of age, were transplanted for hematologic malignancies. Thirty-seven of 43 evaluable patients had evidence of sustained marrow engraftment. Five patients died before day 17 after transplantation. The median time to an absolute neutrophil count of > 0.5 x 10(5)/L was 21 (range, 14 to 30) days. Nephrotoxicity (serum creatinine concentration > 2 mg/dL or doubling of baseline) occurred in 32 patients (74% cumulative incidence during the first 100 days after transplant). Other adverse effects included hypertension (n = 27), hyperglycemia (n = 27), neurotoxicity (n = 9) and thrombotic thrombocytopenic purpura (n = 2). Severe veno-occlusive disease of the liver occurred in 9 (21%) of the 43 patients. Eighteen patients (42%) developed grades II to IV acute GVHD and five (12%) developed grades III to IV acute GVHD. Twelve of 25 evaluable patients developed extensive chronic GVHD within 1 year of marrow transplantation resulting in an estimate of the probability of developing this complication of 48%. The cumulative incidence of transplant-related mortality during the first 100 days was 37%. Kaplan-Meier estimates of disease-free survival at 2 years for good-risk, poor-risk, and all patients were 65%, 4%, and 32%, respectively. FK506 in combination with a short course of MTX appears active in preventing acute GVHD after marrow transplantation from unrelated donors. Further studies comparing the combination of FK506 and MTX with cyclosporine and MTX for the prevention of acute GVHD are warranted.

Adolescent↗
PubMed1996

Hyperlipidemia after liver transplantation: natural history and treatment with the hydroxy-methylglutaryl-coenzyme A reductase inhibitor pravastatin.

This study was designed to determine the frequency of hyperlipidemia after orthotopic liver transplantation and whether treatment with a hydroxy-methylglutaryl coenzyme A reductase inhibitor was safe and efficacious. Cholesterol levels were assessed in 45 consecutive adult liver transplants (mean +/- SE). Four of 22 patients on cyclosporine (CsA) (18%) and three of 23 patients on FK506 (13%) had levels >225 mg/dl at 12 months (cholesterol levels for patients on CsA [total n=22]: pre-Tx = 140+/-11, 1 month = 183+/-36,3 months = 221+/-12, 6 months = 211+/-11, 12 months = 202+/-14 [P<0.01 vs. pre-Tx]; FK506 [total n=23]: Pre-Tx = 151+/-13, 1 month = 187+/-22, 3 months = 188+/-10, 6 months = 184+/-13, 12 months = 164+/-9 [P=0.02 vs. CsA]). A separate cohort of patients with stable graft function, cholesterol >225 mg/dl, and two additional risk factors for coronary artery disease were started on pravastatin. Ninety-eight patients were enrolled. Sixteen patients (16%) discontinued the drug because of subjective complaints. No episodes of rhabdomyolysis or hepatotoxicity occurred (cholesterol levels for patients on CsA [total n=65]: pretreatment = 251+/-7, 6 months = 220+/-7 [P=0.01 vs. pretreatment], 12 months = 224+/-8 [P=0.01 vs. pretreatment]; FK506 [total n=17]: pretreatment = 251+/-17, 6 months = 219+/-17, 12 months = 208+/-17 [P=0.08 vs. pretreatment]). Natural killer cells isolated from normal volunteers (n=14) exhibited 27+/-9% specific lysis. Patients on FK506 or cyclosporine-based immunosuppression alone (n=11) exhibited 20+/-4% specific lysis. Standard immunosuppression plus pravastatin (n=10) decreased lysis to 0.2+/-10% (P<0.02 vs. controls and standard immunosuppression). We conclude: (1) posttransplant hyperlipidemia occurs less frequently in liver transplant patients than in renal or cardiac transplants; (2) pravastatin is safe and efficacious for cholesterol reduction in liver transplant patients; and (3) pravastatin coadministered with standard immunosuppression reduces natural killer cell-specific lysis in these recipients.

Adult↗
PubMed1996

Allogeneic peripheral blood stem cell transplantation in patients with advanced hematologic malignancies: a retrospective comparison with marrow transplantation.

Allogeneic peripheral blood stem cell (PBSC) transplants from HLA-identical siblings were performed in 37 patients with advanced hematologic malignancies. Outcomes were compared to a historical group of 37 similar patients with advanced hematologic malignancies receiving bone marrow (BM) transplants from HLA-identical donors. The PBSC group and historical BM group were well matched for diagnosis, disease stage, age, and graft-versus-host disease (GVHD) prophylaxis. Patients received PBSC transplants between 1993 to 1995 while BM patients were treated between 1989 to 1994. Engraftment, measured by the time to reach a peripheral neutrophil count > 500/L and platelet count > 20,000/microL without transfusions, occurred on days 14 and 11 in the patients transplanted with PBSC compared to days 16 and 15 in the patients receiving BM (P = .00063, .00014). The PBSC group required a median of 8 U of red blood cells and 24 U of platelets compared to 17 U of red blood cells and 118 U of platelets for BM transplant recipients (P = .0005, .0001). The estimated risks of developing grades 2 to 4 acute GVHD were 37% for the PBSC group and 56% for the BM group (P = .18), while the estimated risks of grades 3 to 4 acute GVHD were 14% for the PBSC group and 33% for the BM group, P = .05). Chronic GVHD occurred in 7 of 18 evaluable patients receiving PBSC and 6 of 23 evaluable patients receiving BM, P = .5. The estimated risks of transplant-related mortality at 200 days were 27% versus 45% (P = .33) relapse were 70% versus 53% (P = .27) and of overall survival were 50% and 41% (P = .39) for patients transplanted with PBSC or BM, respectively. This retrospective comparison suggests that compared to marrow transplantation from HLA-identical donors, allogeneic PBSC transplantation from HLA-identical donors is associated with faster engraftment, fewer transfusions, and no greater incidence of acute or chronic GVHD.

Adult↗
PubMed1996

Structure and organization of the mouse elk1 gene.

In the ets gene family of transcription factors, elk1 belongs to the subfamily of Ternary Complex Factors (TCFs) which bind to the Serum Response Element (SRE) in conjunction with a dimer of Serum Response Factors (SRFs). In this communication we report the isolation of cDNAs from the mouse elk1 gene, containing the full coding sequence homologous (87% identical) to the human gene, and the structure and organization of 22 kb of the mouse elk1 locus. The coding sequence is spread through 5 exons (numbered 1 to 5): exons 1 to 4 range from 102 bp to 447 bp and exon 5 is at least 620 bp. Exon 0 was not found in the 8.5 kb sequence upstream of exon 1. The intron between exons 1 and 2 is 4 kb long and the 3 other introns are less than 500 bp long. This information will be useful to engineer targeted mutations of this gene in mice and to determine the genomic structure of the other TCF genes.

Amino Acid Sequence↗
PubMed1996

Carcinoma cell lines become sensitive to DNA-damaging agents by the expression of the adenovirus E1A gene.

Squamous cell carcinomas can show different oncogenic alterations, histological patterns, and an unpredictable clinical behavior. We previously reported that the adenovirus E1a gene may induce sensitivity to DNA-damaging agents in mouse keratinocytes. In order to study whether E1a expression could be used as a therapeutic agent in different malignant cell lines carrying mutations on the p53 gene and other oncogenic alterations, we transfected and infected several murine and human carcinoma cell lines (HaCa4; MSC11A5; HeLa) with vectors containing the 13S or 12S E1a region. We evaluated the sensitivity to cisplatin (CDDP), doxorubicin (DOX) and gamma irradiation (RX) by the crystal violet method. The induction of apoptosis was assessed by flow cytometry and presence of DNA ladders in agarose gels. The expression of E1a and the tumor suppressor p53 protein was analysed by Western blotting. The carcinoma cell lines expressing E1a were about four- to tenfold more sensitive to CDDP and RX, respectively, than the control cells. Moreover, the reduction in cell viability and cell growth after exposure to CDDP or RX was very significant in the carcinoma cells expressing E1a. With these results, we conclude that expression of E1a may confer great sensitivity to DNA-damaging agents on squamous cell carcinoma cells independently of the p53 protein status and other oncogenic alterations.

Adenoviridae↗