Search PubMed⌕ Search

Biomedical subjects

J M Lipton

Publications and source records attributed to J M Lipton.

At least 19 recordsLinked to original sources
PubMed2005

Three-dimensional structure of the alpha-MSH-derived candidacidal peptide [Ac-CKPV]2.

Previous research has shown that the immunomodulatory peptide alpha-melanocyte-stimulating hormone (alpha-MSH) and its carboxy-terminal tripeptide KPV (Lys-Pro-Val alpha-MSH11-13) have antimicrobial influences. By inserting a Cys-Cys linker between two units of KPV, we designed the dimer [Ac-CKPV]2 that showed excellent candidacidal effects in pilot tests and was the subject of further investigations. [Ac-CKPV]2 was active against azole-resistant Candida spp. Therefore, the molecule appeared a promising candidate for therapy of fungal infections and was the subject of a structural study. 1H-NMR and restrained mechanic and dynamic calculations suggest that the peptide adopts an extended backbone structure with a beta-turn-like structure. These results open a pathway to development of additional novel compounds that have candidacidal effects potentially useful against clinical infections.

Antifungal Agents↗
PubMed2001

Thiopental inhibits NF-kappaB activation in human glioma cells and experimental brain inflammation.

Thiopental is one of the intravenous anesthetics used widely. Several reports have demonstrated that thiopental inhibits the immune responses. We investigated whether or not thiopental inhibits the production of tumor necrosis factor-alpha (TNF-alpha) induced by lipopolysaccharide (LPS) in human glioma cells (A-172). Moreover, we determined whether or not thiopental modulates activation of the transcription factor NF-kappaB, a factor that regulates expression of the genes that code for proinflammatory cytokines in A-172 cells and in experimental murine brain inflammation. Thiopental inhibited TNF-alpha production induced by LPS in A-172 cells. Electrophoretic mobility shift assays demonstrated that thiopental inhibited NF-kappaB activation induced by LPS in A-172 cells. In experimental murine brain inflammation induced by intracerebroventricular injection of LPS, intraperitoneal injection of thiopental inhibited NF-kappaB activation. Western blot analysis indicated that this inhibition was linked to preservation of IkappaBalpha protein expression in A-172 cells. The chloramphenicol acetyltransferase assay revealed that NF-kappaB-dependent reporter gene expression was suppressed in A-172 cells exposed to thiopental. These findings are consistent with the idea that thiopental exerts antiinflammatory effects in cultured cells and experimental murine brain inflammation, through suppression of TNF-alpha production via inhibition of NF-kappaB activation.

Anesthetics, Intravenous↗
PubMed2001

Bilateral microtia and cleft palate in cousins with Diamond-Blackfan anemia.

We report on maternal first cousins with bilateral microtia, micrognathia, cleft palate and hematologic findings of Diamond-Blackfan anemia (DBA). The similarity of findings shared between our cases and a female reported by Hasan and Inoue [1993] suggests that this is a distinctive syndrome, rather than a chance association. DBA is a heterogeneous disorder, caused in about 25% of cases by heterozygous mutations in the RPS19 gene (DBA1). Mutation analysis in our cases did not show an RPS19 mutation, and 2 alleles were present in each. Segregation analysis for DBA1 on chromosome 19 and DBA2 on 8p23 was not consistent with linkage. We conclude that this syndrome of microtia, cleft palate and DBA is not allelic to known DBA loci.

Abnormalities, Multiple↗
PubMed2001

Evidence for linkage of familial Diamond-Blackfan anemia to chromosome 8p23.3-p22 and for non-19q non-8p disease.

Diamond-Blackfan anemia (DBA) is a rare congenital hypoplastic anemia that usually presents early in infancy and is inherited in 10% to 20% of cases. Linkage analysis has shown that DBA in many of both dominant and recessive DBA families mapped to chromosome 19q13.2 leading to the cloning of a gene on chromosome 19q13.2 that encodes a ribosomal protein, RPS19. However, subsequently, mutations of the RPS19 gene have only been identified in 25% of all patients with DBA. This study analyzed 14 multiplex DBA families, 9 of which had 19q13.2 haplotypes inconsistent with 19q linkage. A genome-wide search for linked loci suggested the presence of a second DBA locus in a 26.4-centimorgan (cM) interval on human chromosome 8p. Subsequently, 24 additional DBA families were ascertained and all 38 families were analyzed with additional polymorphic markers on chromosome 8p. In total, 18 of 38 families were consistent with linkage to chromosome 8p with a maximal LOD score with heterogeneity of 3.55 at D8S277 assuming 90% penetrance. The results indicate the existence of a second DBA gene in the 26.4-cM telomeric region of human chromosome 8p23.3-p22, most likely within an 8.1-cM interval flanked by D8S518 and D8S1825. Seven families were inconsistent with linkage to 8p or 19q and did not reveal mutations in the RPS19 gene, suggesting further genetic heterogeneity. (Blood. 2001;97:2145-2150)

Chromosomes, Human, Pair 19↗
PubMed2001

Hematopoietic stem cell transplantation for Diamond Blackfan anemia: a report from the Diamond Blackfan Anemia Registry.

The Diamond Blackfan Anemia (DBA) Registry of North America is a detailed database of patients with DBA from the United States and Canada. To date, 354 patients have been registered. From this database an analysis of the outcome of hematopoietic stem cell transplantation for DBA was undertaken. Of the 20 transplanted patients who met criteria for the diagnosis of DBA, eight underwent an allogeneic HLA-matched sibling hematopoietic stem cell transplant (SCT) and 12 an alternative donor SCT. The median age at transplant for all patients was 6 years 2 months; 3 years 10 months vs 9 years 1 month for HLA-matched sibling and alternative donor SCT, respectively. All of the HLA-matched sibling transplants were done using a non-irradiation-containing regimen, whereas the majority of alternative donor transplants were performed using total body irradiation. The survival for HLA-matched sibling vsalternative donor transplant was 87.5% +/- 11.7% vs 14.1% +/- 12.1% at greater than 5 years from SCT (P = 0.015). The use of HLA-matched sibling SCT should be considered for all patients with suitable donors. However, alternative donor SCT in DBA must be approached cautiously, the potential for severe aplastic anemia (SAA) or hematopoietic malignancy not withstanding.

Adolescent↗
PubMed2001

Osteogenic sarcoma associated with Diamond-Blackfan anemia: a report from the Diamond-Blackfan Anemia Registry.

PURPOSE: Diamond-Blackfan anemia (DBA) is a congenital pure red cell aplasia, usually presenting in infancy or early childhood. A review of the literature strongly supports a predisposition to hematopoietic malignancy. Recently, solid tumors have been reported, some attributable to hemosiderosis and/or androgen therapy. Two cases of osteogenic sarcoma have also been documented. An analysis from the Diamond-Blackfan Anemia Registry was performed to evaluate the cancer risk in patients with DBA. METHODS: The Diamond-Blackfan Anemia Registry of North America (DBAR) is a comprehensive database of patients with DBA enrolled, after informed consent, through outreach to pediatric hematologists and family groups. The patients and/or their families complete a detailed questionnaire, and a review of medical records and telephone interviews are performed to complete and clarify the information provided. RESULTS: Of the 354 patients registered in the DBAR, there were six patients meeting the accepted diagnostic criteria for DBA who were found to have malignancies. Three patients had osteogenic sarcoma diagnosed, one with myelodysplastic syndrome, one with colon carcinoma, and one with a soft tissue sarcoma. CONCLUSION: There appears to be an association of osteogenic sarcoma with DBA. A young age at presentation may be a feature of DBA-associated osteogenic sarcoma. Because of the immaturity of the database, the actuarial risk for osteogenic sarcoma and other cancers in individuals with DBA cannot be ascertained. Speculation is made regarding the nature of the molecular defect leading to the association of DBA and osteogenic sarcoma.

Adolescent↗
PubMed2001

Thrombocytopenia absent corpus callosum syndrome: third case of a distinct clinical entity.

Thrombocytopenia absent corpus callosum, characterized by refractory thrombocytopenia, agenesis of the corpus callosum, hypoplastic cerebellum, abnormal facies, and developmental delay, represents a relatively newly described clinical entity. An 18-month-old girl with agenesis of the corpus callosum, hypoplasia of the cerebellar vermis, hypotonia, and severe developmental delay presented with thrombocytopenia. She had a distinctive facies with microcephaly, broad nasal root with upturned nose, small upper lip, and micrognathia. A bone marrow aspirate and biopsy showed normal cellularity with dysplastic megakaryocytes. Thrombocytopenia absent corpus callosum is compared with other conditions characterized by congenital non-immune thrombocytopenia.

Abnormalities, Multiple↗
PubMed2000

Sodium valproate inhibits production of TNF-alpha and IL-6 and activation of NF-kappaB.

Sodium valproate (VPA) is frequently used to treat epilepsy and convulsive disorders. Several reports have indicated that anti-epileptic drugs (AED) affect the immune system, but the mechanism has not been clear. We examined whether the commonly used AEDs, diazepam (DZP), carbamazepine (CBZ), phenobarbital (PB), phenytoin (PHT), and VPA, can inhibit activation of the nuclear transcription factor kappa B (NF-kappaB), in human monocytic leukemia cells (THP-1) and in human glioma cells (A-172). NF-kappaB is essential to the expression of the kappa light chain of immunoglobulin and proinflammatory cytokines. Electrophoretic mobility shift assays (EMSA) of nuclear extracts demonstrated that VPA inhibits NF-kappaB activation induced by lipopolysaccharide (LPS), but the other AEDs do not. Western blot analysis revealed that this inhibition is not linked to preservation of expression of IkappaBalpha protein. Chloramphenicol acetyltransferase (CAT) assay indicated that NF-kappaB-dependent reporter gene expression is suppressed in glioma cells pretreated with VPA. VPA significantly inhibited LPS-induced production of TNF-alpha and IL-6 by THP-1 cells, whereas other AEDs did not. The findings are consistent with the idea that VPA suppresses TNF-alpha and IL-6 production via inhibition of NF-kappaB activation. Our results suggest that VPA can modulate immune responses in vitro. These findings raise the possibility that such modulation might occur with clinical use of VPA.

Anticonvulsants↗
PubMed2000

Antimicrobial effects of alpha-MSH peptides.

The presence of the ancient anti-inflammatory peptide alpha-melanocyte-stimulating hormone [alpha-MSH (1-13), SYSMEHFRWGKPV] in barrier organs such as gut and skin suggests a role in the nonspecific (innate) host defense. alpha-MSH and and its carboxy-terminal tripeptide (11-13, KPV) were determined to have antimicrobial influences against two major and representative pathogens: Staphylococcus aureus and Candida albicans. alpha-MSH peptides significantly inhibited S. aureus colony formation and reversed the enhancing effect of urokinase on colony formation. Antimicrobial effects occurred over a broad range of concentrations including the physiological (picomolar) range. Small concentrations of alpha-MSH peptides likewise reduced viability and germ tube formation of the yeast C. albicans. Antimicrobial influences of alpha-MSH peptides could be mediated by their capacity to increase cellular cAMP. Indeed, this messenger was significantly augmented in peptide-treated yeast and the potent adenylyl cyclase inhibitor dideoxyadenosine (ddAdo) partly reversed the killing activity of alpha-MSH peptides. Reduced killing of pathogens is a detrimental consequence of therapy with anti-inflammatory drugs. Because alpha-MSH has potent anti-inflammatory effects we determined influences of alpha-MSH on C. albicans and S. aureus killing by human neutrophils. alpha-MSH peptides did not reduce killing but rather enhanced it, likely as a consequence of the direct antimicrobial activity. alpha-MSH peptides that combine antipyretic, anti-inflammatory, and antimicrobial effects could be useful in treatment of disorders in which infection and inflammation coexist.

Anti-Bacterial Agents↗
PubMed2000

Ketamine suppresses endotoxin-induced NF-kappaB expression.

PURPOSE: Ketamine reduces endotoxin-induced production of proinflammatory cytokines, including tumour necrosis factor-alpha (TNF), in several types of inflammatory cells, including monocytes and macrophages. Transcription of the genes that encode production of these proinflammatory cytokines is regulated by nuclear factor-kappa B (NF-kappaB). Cytoplasmic B protein is activated by endotoxin (LPS) as well as by TNF, allowing B protein to migrate into the cell nucleus to activate gene transcription for these inflammatory mediators. Because NF-kappaB is likely involved in brain injury and inflammatory neurodegenerative disease, such as multiple sclerosis, we examined whether ketamine inhibits LPS-induced activation of NF-kappaB in human glioma cells in vitro and intact mouse brain cells in vivo. METHODS: Endotoxin-induced NF-kappaB expression in both the human glioma cells in vitro and the intact mouse brain cells in vivo was determined by electrophoretic mobility shift assays (EMSA) of nuclear extracts and measurement of NF-kappaB expression by densitometry. Endotoxin was injected intracerebroventricularly in vivo and intact brain was harvested. Klenow fragment labeling was used to identify NF-kappaB protein for both the in vivo and vitro experiments. RESULTS: Endotoxin treatment increased NF-kappaB expression (P < 0.05) both in vivo and vitro compared with control (untreated) cells. Ketamine suppressed endotoxin-induced neuronal NF-kappaB activation in a dose-dependent manner (P < 0.05, except for the 10(-5) M concentration in vitro) both in vivo and vitro. CONCLUSION: Ketamine inhibits endotoxin-induced NF-kappaB expression in brain cells in vivo and vitro and it is suggested that this may have implications in the neuroprotective effects of ketamine reported by other investigators.

Animals↗
PubMed2000

NF-kappaB activation is inhibited in human pulmonary epithelial cells transfected with alpha-melanocyte-stimulating hormone vector.

alpha-Melanocyte-stimulating hormone (alpha-MSH) modulates inflammation. We investigated the influence of alpha-MSH on NF-kappaB activation in human pulmonary epithelial cells (A549) using a plasmid vector encoding alpha-MSH (pCMV-ssMSH). Electrophoretic mobility shift assays demonstrated that NF-kappaB activation induced by lipopolysaccharide was inhibited in A549 cells transfected with pCMV-ssMSH. Western blot analysis revealed that this inhibition was linked to preservation of expression of IkappaBalpha protein. Chloramphenicol acetyltransferase assay indicated that NF-kappaB-dependent reporter gene expression was suppressed in A549 cells transfected with pCMV-ssMSH. The findings indicate that anti-inflammatory actions are exerted via modulation of NF-kappaB activation by preservation of IkappaBalpha protein in human pulmonary epithelial cells transfected with alpha-MSH vector. We showed a possibility of gene therapy for chronic inflammatory lung diseases.

Amino Acid Sequence↗
PubMed2000

Alpha-melanocyte-stimulating hormone in normal human physiology and disease states.

Over the past two decades, research in animal models has indicated that alpha-melanocyte-stimulating hormone (alpha-MSH) has potent anti-inflammatory properties. Furthermore, recent data show that the peptide has antimicrobial effects and probably contributes to innate immunity. alpha-MSH, which is produced by many extrapituitary human cells, should no longer be considered solely a pituitary hormone; rather, it should be viewed as a ubiquitous modulatory peptide.

Animals↗
PubMed2000

Results of Dana-Farber Cancer Institute Consortium protocols for children with newly diagnosed acute lymphoblastic leukemia (1981-1995).

The Dana-Farber Cancer Institute (DFCI) ALL consortium has been conducting clinical trials in childhood acute lymphoblastic leukemia (ALL) since 1981. The treatment backbone has included intensive, multi-agent remission induction, early intensification with weekly, high-dose asparaginase, cranial radiation for the majority of patients, frequent vincristine/ corticosteroid pulses during post-remission therapy, and for high-risk patients, doxorubicin during intensification. Between 1981 and 1995, 1,255 children with newly diagnosed ALL were evaluated on four consecutive protocols: 81-01 (1981-1985), 85-01 (1985-1987), 87-01 (1987-1991) and 91-01 (1991-1995). The 5-year event-free survival (EFS) rates (+/- standard error) for all patients by protocol were as follows: 74 +/- 3% (81-01), 78 +/- 3% (85-01), 77 +/- 2% (87-01) and 83 +/- 2% (91-01). The 5-year EFS rates ranged from 78 to 85% for patients with B-progenitor phenotype retrospectively classified as NCI standard-risk, 63-82% for NCI high-risk B-progenitor patients, and 70-79% for patients with T cell phenotype. Results of randomized studies revealed that neither high-dose methotrexate during induction (protocol 87-01) nor high-dose 6-mercaptopurine during intensification (protocol 91-01) were associated with improvement in EFS compared with standard doses. Current studies continue to focus on improving efficacy while minimizing acute and late toxicities.

Adolescent↗
PubMed2000

Plasma concentrations of alpha-melanocyte-stimulating hormone are elevated in patients on chronic haemodialysis.

BACKGROUND: Clinical and/or laboratory signs of systemic inflammation occur frequently in patients undergoing long-term haemodialysis. It is likely, therefore, that a compensatory release of endogenous anti-inflammatory molecules occurs to limit host reactions. The aim of the present research was to determine if the potent anti-inflammatory peptide alpha-melanocyte-stimulating hormone (alpha-MSH), a pro-opiomelanocortin derivative, is increased in plasma of haemodialysis patients. Because endotoxin and cytokines induce alpha-MSH in vivo and in vitro, we also measured plasma concentrations of endotoxin, interleukin-6 (IL-6), and tumour necrosis factor alpha (TNF-alpha), and the two circulating products of activated monocytes, nitric oxide (NO) and neopterin. METHODS: Thirty-five chronic haemodialysis patients, 20 patients with chronic renal failure not yet on dialysis, and 35 normal controls were included in the study. In the haemodialysis group, blood samples were obtained before and at the end of a dialysis session. Plasma alpha-MSH was measured using a double antibody radioimmunoassay, and IL-6, TNF-alpha, and neopterin using specific enzyme-linked immunosorbent assays. Plasma nitrites were determined by a colorimetric method, and endotoxin with the quantitative chromogenic LAL (limulus amoebocyte lysate) method. RESULTS: Mean plasma alpha-MSH was higher in haemodialysis patients than in control subjects, with the peptide concentrations being particularly elevated in dialysed patients with detectable endotoxin. High alpha-MSH concentrations were observed in the pre-dialysis samples, with no substantial change at the end of the dialysis session. Plasma concentrations of IL-6, TNF-alpha, neopterin, and NO were generally elevated in chronic haemodialysis patients and there was a negative correlation between circulating alpha-MSH and IL-6. In patients with renal failure not yet on dialysis, mean plasma alpha-MSH was similar to that of normal subjects. CONCLUSIONS: alpha-MSH is increased in the circulation of chronic haemodialysis patients and particularly so in case of detectable endotoxaemia. Reduction of renal clearance is unlikely to contribute to the observed rise of the peptide because alpha-MSH concentration is not increased in patients with chronic renal failure who are not yet on dialysis. It is likely that dialysis-associated endotoxaemia, directly and/or through cytokine release, enhances the production of the anti-inflammatory mediator alpha-MSH that limits host reactions.

Adult↗
PubMed2000

Plasma concentrations and anti-L-cytokine effects of alpha-melanocyte stimulating hormone in septic patients.

OBJECTIVES: The aim of this research was to investigate endogenous concentrations and anti-cytokine effects of the antiinflammatory peptide alpha-melanocyte stimulating hormone (alpha-MSH) in patients with systemic inflammation. The objectives were to determine the following: changes over time of plasma alpha-MSH and relationship with patient outcome, correlation between plasma alpha-MSH and tumor necrosis factor (TNF)-alpha plasma concentration and production in whole blood samples, and influences of alpha-MSH on production of TNF-alpha and interleukin (IL)-1beta in whole blood samples stimulated with lipopolysaccharide (LPS). DESIGN: Prospective, nonrandomized, clinical study. SETTING: Intensive care unit of a university hospital. PATIENTS: A total of 21 patients with sepsis syndrome/septic shock and an equal number of healthy volunteers. INTERVENTIONS: Circulating alpha-MSH and TNF-alpha concentrations and TNF-alpha production in supernatants of LPS (1 ng/mL)-stimulated whole blood were measured repeatedly. To determine whether alpha-MSH can modulate production of TNF-alpha and IL-1 beta, these cytokines were measured in whole blood samples stimulated with LPS (1 ng/mL) in the presence or absence of concentrations of the peptide. MEASUREMENTS AND MAIN RESULTS: Plasma alpha-MSH was low in early samples and gradually increased in patients who recovered but not in those who died. There was a negative correlation between plasma concentrations of alpha-MSH and TNF-alpha. In blood samples taken at early phases of sepsis syndrome, production of TNF-alpha was reduced relative to control values; such production increased in patients who recovered but not in those who died. Addition of alpha-MSH to LPS-stimulated whole blood samples inhibited production of TNF-alpha and IL-1beta in a concentration-dependent manner. CONCLUSIONS: In patients with systemic inflammation, there are substantial changes over time in plasma concentrations of alpha-MSH that are reduced in early phases of the disease. Reduction of this endogenous modulator of inflammation could be detrimental to the host. Addition of alpha-MSH to LPS-stimulated blood samples reduces production of cytokines involved in development of septic syndrome. This inhibition by alpha-MSH, a peptide that is beneficial in treatment of experimental models of sepsis, might therefore be useful to treat sepsis syndrome in humans.

Adult↗
PubMed2000

The neuroimmunomodulatory peptide alpha-MSH.

Alpha-melanocyte-stimulating hormone (alpha-MSH), a neuroimmunomodulatory peptide of ancient origin, is known to be involved in the control of host responses. In inflammatory cells, in the periphery and within the central nervous system, alpha-MSH modulates the production and action of proinflammatory cytokines. This broad influence occurs via endogenous alpha-MSH (melanocortin) receptors. The key to this anti-inflammatory influence is inhibition of NF-kappa B. Indeed alpha-MSH inhibits activation of this nuclear factor through preservation of I kappa B alpha, which binds to NF-kappa B and prevents its migration to the nucleus. Cells transfected with alpha-MSH plasmid vector are resistant to challenge with bacterial lipopolysaccharide. The peptide also act on central melanocortin receptors to modulate inflammation in the periphery. In brief, alpha-MSH and certain of its fragments such as alpha-MSH [11-13] KPV modulate inflammation via three general actions: direct actions on peripheral host cells; actions on inflammatory cells within the brain to modulate local reactions; and descending neural anti-inflammatory pathways that control inflammation in peripheral tissues.

Animals↗
PubMed2000

The neuropeptide alpha-MSH in host defense.

The presence of the ancient peptide alpha-melanocyte-stimulating hormone (alpha-MSH) in barrier organs such as gut and skin suggests that this potent anti-inflammatory molecule may be a component of the innate host defense. In tests of antimicrobial activities, alpha-MSH and its fragment KPV showed inhibitory influences against the gram-positive bacterium Staphylococcus aureus and the yeast Candida albicans. Anti-tumor necrosis factor and antimicrobial effects of alpha-MSH suggest that the peptide might likewise reduce replication of human immunodeficiency virus (HIV). Treatment with alpha-MSH reduced HIV replication in chronically and acutely infected human monocytes. At the molecular level, alpha-MSH inhibited activation of the transcription factor NF-kappa B known to enhance HIV expression. alpha-MSH that combines antipyretic, anti-inflammatory, and antimicrobial effects could be useful in the treatment of disorders in which infection and inflammation coexist.

Animals↗