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Friedman Y, Fildes J, Mizock B, Samuel J, Patel S, Appavu S, Roberts R. Comparison of percutaneous and surgical tracheostomies. Chest 1996; 110:480-5. [PMID: 8697854 DOI: 10.1378/chest.110.2.480] [Citation(s) in RCA: 201] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 02/01/2023] Open
Abstract
OBJECTIVE To compare the safety and efficacy of percutaneous dilational tracheostomy (PDT) with surgical tracheostomy (ST). DESIGN Prospective randomized trial. SETTING Public urban teaching hospital. PATIENTS Twenty-six patients were randomized to undergo PDT and 27 patients to ST. RESULTS The time from randomization into the study until tracheostomy was performed was 28.5 +/- 27.9 h in the PDT group and 100.4 +/- 95.0 h in the ST group (p < 0.001). PDT was performed in 8.2 +/- 4.9 min vs 33.9 +/- 14.0 min for ST (p < 0.0001). There was no significant difference in intraprocedural complications between the groups. Postprocedural complication rates were 12% for PDT and 41% for ST (p = 0.008). CONCLUSION PDT is superior to ST logistically. PDT can be performed at the bedside eliminating the risk of patient transport. Because operating room scheduling is not necessary, PDT can be performed earlier once the decision to do a tracheostomy is made, which will improve ICU utilization. PDT is a faster procedure to perform and has fewer postprocedural complications.
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Wang D, Robinson DR, Kwon GS, Samuel J. Encapsulation of plasmid DNA in biodegradable poly(D, L-lactic-co-glycolic acid) microspheres as a novel approach for immunogene delivery. J Control Release 1999; 57:9-18. [PMID: 9863034 DOI: 10.1016/s0168-3659(98)00099-6] [Citation(s) in RCA: 201] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 11/21/2022]
Abstract
A plasmid DNA encoding bacterial beta-galactosidase gene was encapsulated in poly(d,l-lactic-co-glycolic acid) (PLGA) microspheres. Plasmid DNA extracted from PLGA microspheres retained both structural and functional integrity as evidenced by its restriction endonuclease digestion pattern and its ability to transfect COS-1 cells in vitro. PLGA microspheres protected plasmid DNA from digestion by deoxyribonuclease I (DNase I) in vitro. The encapsulation efficiency of plasmid DNA and its release rate depended on the molecular mass of PLGA. Lastly, J-774A macrophages phagocytosed PLGA microspheres loaded with plasmid DNA. Co-encapsulated monophosphoryl lipid A increased the rate of phagocytosis. These results suggest that biodegradable PLGA microspheres can deliver intact and functional plasmid DNA at controlled rates. Thus, PLGA microspheres may be used to jointly deliver genes and other biologically active molecules, e.g., immunomodulators, to antigen presenting cells.
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MacLean GD, Reddish M, Koganty RR, Wong T, Gandhi S, Smolenski M, Samuel J, Nabholtz JM, Longenecker BM. Immunization of breast cancer patients using a synthetic sialyl-Tn glycoconjugate plus Detox adjuvant. Cancer Immunol Immunother 1993; 36:215-22. [PMID: 8439984 PMCID: PMC11038621 DOI: 10.1007/bf01740902] [Citation(s) in RCA: 137] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 10/08/1992] [Accepted: 11/06/1992] [Indexed: 01/30/2023]
Abstract
We have synthesized various formulations that have potential for active specific immunotherapy (ASI) of human cancers. Sialyl-Tn (STn) is a potentially important target structure for ASI because its expression on mucins is a strong, independent predictor of poor prognosis, suggesting that it may have functional significance in the metastatic process. In this first pilot study of synthetic sialyl-Tn hapten conjugated to keyhole limpet hemocyanin (STn-KLH), with Detox adjuvant, toxicity and humoral immunogenicity were assessed in 12 patients with metastatic breast cancer. Toxicity was minimal, restricted to local cutaneous reactions (apart from transient nausea and vomiting following single low-dose cyclophosphamide treatment). Using STn-conjugated human serum albumin in a solid-phase enzyme-linked immunosorbent assay, it was shown that all patients developed IgM and IgG specific for the synthetic STn hapten. Following immunization, most patients were shown to develop increased titres of complement-mediated cytotoxic antibodies, partially inhibited by synthetic STn hapten, but not by the related TF hapten. We also detected IgM and IgG antibodies reactive with natural STn determinants expressed on ovine submaxillary mucin, the STn specificity of this reactivity being confirmed by hapten inhibition. Evaluation of clinical efficacy in a small pilot study is difficult. Five patients are alive 12 or more months after entry, and another 4 patients are alive 6 or more months after entry into the study. All 3 patients with known widespread bulky disease progressed despite ASI, 2 having died from widespread cancer. Two patients had partial responses, each lasting 6 months. While several patients had disease stability for 3-10 months, 1 patient with pulmonary metastases remains stable 15 months after entry into the program.
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Raj K, John A, Ho A, Chronis C, Khan S, Samuel J, Pomplun S, Thomas NSB, Mufti GJ. CDKN2B methylation status and isolated chromosome 7 abnormalities predict responses to treatment with 5-azacytidine. Leukemia 2007; 21:1937-44. [PMID: 17611569 DOI: 10.1038/sj.leu.2404796] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 01/11/2023]
Abstract
5-Azacytidine, a DNA methyl transferase inhibitor, is effective in patients with myelodysplastic syndromes (MDS). Whether responses to 5-Azacytidine are achieved by demethylation of key genes or by cytotoxicity is unclear. Of 34 patients with MDS or acute myeloid leukaemia (AML) treated with 5-Azacytidine, 7 achieved complete remissions (CR) (21%) and 6 achieved haematological improvement. All six had less than 5% bone marrow (BM) blasts at the time of haematological improvements (HI) (2 had pre-existing refractory anaemia (RA), 4 had refractory anaemia with excess blasts (RAEB)). A further patient with RAEB had blast reduction to less than 5% without HI. Five of the seven (71%) complete responders had chromosome 7 abnormalities. BM CR predicted longer overall survival (OS) (median 23 versus 9 months, P=0.015). Bisulphite genomic sequencing (BGS) of the CDKN2B (p15(INK4b)) promoter showed low level, heterogeneous pretreatment methylation (mean 12.2%) in 14/17 (82%) patients analysed. Lower baseline methylation occurred in responders (9.8% versus 16.2% in non-responders P=0.07). No response was seen in patients with >24% methylation, in whom p15(INK4b) mRNA was not expressed. 5-Azacytidine reduced CDKN2B methylation by mean 6.8% in 8/17 (47%) patients, but this did not correlate with response. At 75 mg/m(2), cell death (reduced BM cellularity (P=0.001) and increased apoptosis (P=0.02)) rather than demethylation of CDKN2B correlates with response. Patients with >24% methylation may benefit from alternative dosing or combination strategies.
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Lavasanifar A, Samuel J, Kwon GS. Micelles self-assembled from poly(ethylene oxide)-block-poly(N-hexyl stearate L-aspartamide) by a solvent evaporation method: effect on the solubilization and haemolytic activity of amphotericin B. J Control Release 2001; 77:155-60. [PMID: 11689268 DOI: 10.1016/s0168-3659(01)00477-1] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 10/18/2022]
Abstract
The goal of this study was to assess a solvent evaporation method for the encapsulation of amphotericin B (AmB) in poly(ethylene oxide)-block-poly(N-hexyl stearate L-aspartamide) (PEO-b-PHSA) micelles. By the solvent evaporation method, PEO-b-PHSA self-assembled into small spherical micelles with a high AmB content based on transmission electron microscopy, size exclusion chromatography and absorption spectroscopy. The encapsulation of AmB was slightly better than an earlier method based on dialysis. Importantly, AmB in PEO-b-PHSA micelles encapsulated by the solvent evaporation method was non-haemolytic at 15 microg/ml, whereas AmB in PEO-b-PHSA micelles encapsulated by the dialysis method caused 50% haemolysis at the level of 3.8 microg/ml, and AmB itself caused 100% haemolysis at 1.0 microg/ml. Thus, PEO-b-PHSA micelles could effectively encapsulate AmB, increase the overall water solubility of AmB and reduce the toxicity of the membrane-acting drug, particularly by a solvent evaporation method.
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Abstract
Three hundred thirty-five cases of acute mastoiditis with complications due to extension of infection beyond the mastoid are reported. Two hundred twenty-four of those presented with intracranial sepsis. Meningitis occurred in 83 cases, brain abscess in 53, extradural abscess in 49 cases, and lateral sinus thrombosis in 39 cases. Intracranial complications are frequently seen in this group of patients with neglected otitis media. The complications occurred frequently in children and young adults (74%) with an overall mortality rate of 14%. Meningitis was the most common complication (37%); brain abscess had the highest mortality rate (36%). The overall mortality rate from intracranial complications was reduced in comparison with previous reported series. This is attributed to antibiotic treatment, the use of CT scan in excluding other intracranial complications, and close cooperation between the otologist and neurosurgeon.
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MacLean GD, Bowen-Yacyshyn MB, Samuel J, Meikle A, Stuart G, Nation J, Poppema S, Jerry M, Koganty R, Wong T. Active immunization of human ovarian cancer patients against a common carcinoma (Thomsen-Friedenreich) determinant using a synthetic carbohydrate antigen. J Immunother 1992; 11:292-305. [PMID: 1599915 DOI: 10.1097/00002371-199205000-00008] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 12/27/2022]
Abstract
In a phase I study, ten ovarian cancer patients with extensive metastatic disease despite chemotherapy were immunized three to eight times subcutaneously with the synthetic form of the immunodominant disaccharide (beta Gal1----3 alpha GalNAc) of the Thomsen-Friedenreich antigen conjugated to KLH (TF alpha-KLH) plus DETOX adjuvant. Six patients were given a "low" dose of TF alpha-KLH (100 micrograms/injection) and four patients were given a "high" dose (500 micrograms/injection). All patients received a single low-dose cyclophosphamide treatment (200 mg/m2 i.v.) 3 days prior to commencement of the series of immunizations. Immunizations were 2 weeks apart. Little or no toxicity was noted. As expected, all patients (prior to immunization) had naturally occurring IgM antibodies against the synthetic TF alpha hapten. None of the patients had detectable pre-existing IgG or IgA antibodies against synthetic TF alpha hapten. Nine of the ten ovarian cancer patients showed a significant increase in IgM titer above pre-existing levels following immunizations with TF alpha-KLH plus DETOX adjuvant. These same patients also produced IgG anti-TF alpha and eight of these also produced IgA anti-TF alpha, although the IgA responses were weaker. Most of the IgG responses followed the IgM responses by 2-4 weeks. Two patients produced a vigorous IgG response after their first TF alpha-KLH injection, suggesting a recall response. Both direct ELISAs on various solid-phase synthetic carbohydrate antigens and hapten inhibition experiments confirmed the TF alpha hapten specificity of the antibodies. IgM and IgG anti-TF alpha-specific antibodies reacted with natural TF antigen, by ELISA and FACS analysis, although the titers were generally lower than the titers against the immunizing TF alpha hapten. Increased levels of cytotoxic antibodies against TF-expressing tumor cell targets were detected in eight of the ten patients following immunization. One patient who had no detectable cytotoxic antibodies prior to immunization developed increasingly strong cytotoxic antibodies as a function of the number of immunizations. The low antigen dose patients showed as good or better humoral immune responses than the high antigen dose patients. All four high-dose and four of six low-dose patients developed moderate to strong DTH reactions at the vaccination sites. Our results demonstrate that KLH is an acceptable carrier for carbohydrate haptens in humans and that DETOX is an appropriate nontoxic adjuvant for the generation of high-titer specific anti-carbohydrate responses in human cancer patients.(ABSTRACT TRUNCATED AT 400 WORDS)
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Samuel J, Oliveira M, Correa De Araujo RR, Navarro MA, Muccillo G. Cardiac thrombosis and thromboembolism in chronic Chagas' heart disease. Am J Cardiol 1983; 52:147-51. [PMID: 6858902 DOI: 10.1016/0002-9149(83)90085-1] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Academic Contribution Register] [Indexed: 01/22/2023]
Abstract
A retrospective study of Chagas' heart disease was carried out by a review of 1,345 autopsy reports, with special reference to cardiac thrombus and thromboembolic phenomena. The incidence of cardiac thrombus was higher in cases of heart failure (36%) than in cases of sudden death (15%), higher in heavier hearts, and unrelated to age or sex. The left- and right-sided cardiac chambers were equally affected by thrombus. Endocarditis and blood stasis were considered important factors in the pathogenesis of cardiac thrombus. Thromboembolic phenomena were more common in the systemic circulation but caused relatively more deaths by pulmonary embolism. Fourteen percent of patients with thromboembolic phenomena died from them. Patients with multiple thromboembolic phenomena had a higher risk of death from embolism. Cardiac thrombosis or thromboembolic phenomena, or both, were present in 44% of the cases studied. Prophylactic measures should be taken for these important complications of Chagas' heart disease.
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Ding L, Lalani EN, Reddish M, Koganty R, Wong T, Samuel J, Yacyshyn MB, Meikle A, Fung PY, Taylor-Papadimitriou J. Immunogenicity of synthetic peptides related to the core peptide sequence encoded by the human MUC1 mucin gene: effect of immunization on the growth of murine mammary adenocarcinoma cells transfected with the human MUC1 gene. Cancer Immunol Immunother 1993; 36:9-17. [PMID: 8422670 PMCID: PMC11039006 DOI: 10.1007/bf01789125] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Received: 06/03/1992] [Accepted: 07/15/1992] [Indexed: 01/30/2023]
Abstract
The immune response of CAF1 mice to various synthetic peptides (SP) related to the amino acid sequence (PDTRPAPGSTAPPAHGVTSA) of the tandem repeat of the MUC1 human breast mucin core peptide was evaluated. The most immunogenic preparations of the synthetic peptides were those conjugated to keyhole limpet hemocyanin (KLH) or clustered in a dendritic multiple antigenic peptide (MAP-4) configuration. The mice were immunized subcutaneously with synthetic peptides emulsified in RIBI adjuvant, employing various immunization protocols. Equivalently high IgG responses were induced using SP-KLH conjugates (GVTSAPDTRPAPGSTA-KLH) or an SP--MAP-4 chimeric configuration (SP1-6), which also included a universal malarial CST-3 T-helper epitope (SP1-6 = SAPDTRPAEKKIAKMEKASSVFNVVNS--MAP-4). These IgG antibodies bound both the appropriate MUC1 synthetic peptides and the cell surface expressed MUC1 mucin on murine mammary cells that had been transfected with the human MUC1 gene and a human breast cancer cell line that expresses cell-surface MUC1. A MAP-4 molecule, which included the entire 20-amino-acid sequence of the MUC1 tandem repeat (SP1-5 = PDTRPAPGSTAPPAHGVTSA-MAP-4) induced a poor IgG response. In contrast, all three types of molecule: SP-KLH, SP1-6 and SP1-5, were found to be good immunogens for the induction of specific delayed-type hypersensitivity (DTH) reactions measured using either synthetic peptides or MUC1-transfected cells. In addition, immunization with irradiated MUC1-transfected cells induced strong DTH reactions measured using synthetic peptides that expressed the PDTRP sequence, which has been shown to be, or to overlap, a T cell epitope in humans and a B cell epitope in mice. Finally, it was demonstrated that synthetic MUC1 peptide "vaccines" could be used both prophylactically and therapeutically to inhibit the growth of MUC1-transfected tumor cells and prolong the survival of tumor-bearing mice.
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Guan HH, Budzynski W, Koganty RR, Krantz MJ, Reddish MA, Rogers JA, Longenecker BM, Samuel J. Liposomal formulations of synthetic MUC1 peptides: effects of encapsulation versus surface display of peptides on immune responses. Bioconjug Chem 1998; 9:451-8. [PMID: 9667946 DOI: 10.1021/bc970183n] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 02/08/2023]
Abstract
Synthetic human MUC1 peptides are important candidates for therapeutic cancer vaccines. To explore whether a human MUC1 peptide BP25 (STAPPAHGVTSAPDTRPAPGSTAPP) can be rendered immunogenic by incorporation in liposomes, the effects of physical association of the peptide with liposomes on immune responses were investigated. Lipid conjugated and nonconjugated MUC1 peptides were incorporated in liposomes with a composition of distearoylphosphatidylcholine/cholesterol/dimyristoylphosphatidylglyc erol (3:1:0.25, molar ratio) containing monophosphoryl lipid A (1% w/w of the total lipids). Liposomes were characterized for peptide retention by HPLC and for surface peptide display of MUC1 epitopes by flow cytometry. C57BL/6 mice were immunized with lipopeptide alone, peptide mixed with peptide-free liposomes, and peptide associated with liposomes in entrapped or surface-exposed forms. T cell proliferative responses, cytokine patterns, and antibody isotypes were studied. Results showed that immune responses were profoundly influenced by the liposome formulations. Physically associated, either encapsulated or surface-exposed, peptide liposomes elicited strong antigen-specific T cell responses, but not lipopeptide alone or peptide mixed with peptide-free liposomes. Analysis of the cytokines secreted by the proliferating T cells showed a high level of IFN-gamma and undetectable levels of IL-4, indicating a T helper type 1 response. Thus, physical association of the peptide with liposomes was required for T cell proliferative responses, but the mode of association was not critical. On the other hand, the nature of the association significantly affected humoral immune responses. Only the surface-exposed peptide liposomes induced MUC1-specific antibodies. A domination of anti-MUC1 IgG2b over IgG1 (94 versus 6%) was observed. Our results support the hypothesis that different immune pathways are stimulated by different liposome formulations. This study demonstrated that a liposome delivery system could be tailored to induce either a preferential cellular or humoral immune response.
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Bhandari R, Samuel J. Observation of topological phase by use of a laser interferometer. PHYSICAL REVIEW LETTERS 1988; 60:1211-1213. [PMID: 10037976 DOI: 10.1103/physrevlett.60.1211] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Academic Contribution Register] [Indexed: 05/23/2023]
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Abstract
Forty-five cases of lateral sinus thrombosis were recorded in King Edward VIII Hospital from 1978 to 1984. Eighty-two per cent of the patients were under the age of 15 years. Associated complications recorded were: 9 patients with meningitis, 4 with posterior-fossa abscess, 1 patient suffering from posterior fossa empyema; 4 presented with facial palsy and 1 with tuberculous mastoiditis. Four deaths were recorded. Findings at mastoidectomy showed a prevalence of infective granulations (60 per cent) over cholesteatoma (40 per cent) as a cause of the extension of infection. The surgical protocol for the management of lateral sinus thrombosis was mastoidectomy, needling the sinus and removal of the thrombus, if necessary. Medical treatment consisted of Ampicillin and Metronidozol.
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Review |
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Franklin C, Samuel J, Hu TC. Life-threatening hypotension associated with emergency intubation and the initiation of mechanical ventilation. Am J Emerg Med 1994; 12:425-8. [PMID: 8031425 DOI: 10.1016/0735-6757(94)90053-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 01/28/2023] Open
Abstract
To determine the incidence of life-threatening hypotension (LTH) suffered by patients in the initial hours after emergency intubation and mechanical ventilation, prospective, consecutive case series of patients undergoing endotracheal intubation and mechanical ventilation were evaluated in the adult emergency department of a large urban hospital. Eight-four medical patients who received intubation and mechanical ventilation for ventilatory failure, respiratory failure, or airway protection (trauma patients exluded) were included. LTH, defined as a decrease in mean arterial pressure of 60 mm Hg or an absolute decrease to a systolic blood pressure < 80 mm Hg in the first 2 hours after intubation, was observed in 24 of the 84 patients who met study criteria (incidence 28.6%). Eleven patients (incidence 13.1%) required treatment for LTH with vasopressors. There was one cardiac arrest, and there were no deaths. There was a statistically significant association between LTH and hypercarbic (PCO2 > 50 mm) chronic obstructive pulmonary disease (COPD) (P = .004). There was also a weaker statistical association between LTH and hypoxemic respiratory failure (P = .019). No association could be established between LTH and the other diagnoses, arterial blood gas (ABG) derangements, or the administration of sedatives or paralytic medications. LTH represents a serious complication of emergency intubation in the initial phase of mechanical ventilation. Because it occurs in more one quarter of all cases, it should be anticipated during intubation and the initial phase of ventilator management, especially in high-risk patients such as those with hypercarbic COPD.(ABSTRACT TRUNCATED AT 250 WORDS)
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Newman KD, Samuel J, Kwon G. Ovalbumin peptide encapsulated in poly(d,l lactic-co-glycolic acid) microspheres is capable of inducing a T helper type 1 immune response. J Control Release 1998; 54:49-59. [PMID: 9741903 DOI: 10.1016/s0168-3659(97)00142-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 11/16/2022]
Abstract
An ovalbumin (OVA) peptide, consisting of residues 323-339, was incorporated into poly(d,l lactic-co-glycolic acid) (PLGA) microspheres and administered to mice. It was hypothesized that microencapsulation of the peptide in PLGA microspheres would avoid the need for traditional adjuvants and bias the immune response towards a type 1 T helper (Th1) response. An immunomodulator, monophosphoryl lipid A (MPLA), was incorporated into the microspheres to determine its efficacy in enhancing a Th1 response. The specificity of the immune response was determined using a T cell proliferation assay. The type of T helper response was determined by analysis of the cytokine secretion profiles of the proliferating T cells. Following s.c. immunization, the results revealed a T cell-specific immune response for the encapsulated OVA peptide both with and without MPLA. The cytokine profiles revealed high levels of IFN-gamma with very low levels of IL-4 and IL-10, suggesting a Th1 response. Furthermore, incorporation of MPLA in the peptide loaded PLGA microspheres resulted in an increase in the production of IFN-gamma. Hence, peptide-loaded PLGA microspheres are capable of eliciting a specific Th1 immune response, which may be further enhanced in the presence MPLA.
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Samuel J, Budzynski WA, Reddish MA, Ding L, Zimmermann GL, Krantz MJ, Koganty RR, Longenecker BM. Immunogenicity and antitumor activity of a liposomal MUC1 peptide-based vaccine. Int J Cancer 1998; 75:295-302. [PMID: 9462722 DOI: 10.1002/(sici)1097-0215(19980119)75:2<295::aid-ijc20>3.0.co;2-b] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 02/06/2023]
Abstract
A human MUC1-transfected mouse mammary adenocarcinoma cell line (GZHI) was used to develop both subcutaneous and intravenous tumor models. A vaccine formulation comprised of a 24 mer (human MUC1) synthetic peptide encapsulated with monophosphoryl lipid A adjuvant (MPLA) in multilamellar liposomes was tested for immunogenicity and anti-tumor activity. A low dose of the human MUC1 peptide (5 microg) administered in liposomes provided excellent protection of mice in both tumor challenge models. The protective antitumor activity mediated by the liposome formulation correlated with anti-MUC1-specific T-cell proliferation, gamma-interferon (IFN-gamma) production and IgG2a anti-MUC1 antibodies, suggesting a type 1 (T1) T-cell response. In contrast, lack of protection in mice immunized with negative control vaccines correlated with IgG1 anti-MUCI antibody formation, low or no anti-MUC1 IgG2a and low antigen-specific T-cell proliferation, consistent with a type 2 (T2) T-cell response to the tumor.
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Lavasanifar A, Samuel J, Kwon GS. The effect of alkyl core structure on micellar properties of poly(ethylene oxide)-block-poly(L-aspartamide) derivatives. Colloids Surf B Biointerfaces 2001; 22:115-126. [PMID: 11451658 DOI: 10.1016/s0927-7765(01)00147-3] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 10/18/2022]
Abstract
Block copolymers based on fatty acid esters of poly(ethylene oxide)-block-poly(hydroxy alkyl L-aspartamide) were prepared and characterized by 1H-NMR. The structure of the core-forming block was changed through application of different lengths of the poly(L-aspartamide) (PLAA) block, spacer group or fatty acid and varying the substitution level of the side chain on the polymeric backbone. Transmission electron microscopy and fluorescent probe studies provided evidence for the formation of supramolecular core/shell architectures with nanoscopic dimensions. The same techniques were used to study the effect of hydrophobic block structure on micellar size, critical micelle concentration (CMC), core polarity and viscosity of the polymeric micelles. Among the structural factors studied, it was revealed that the length of the PLAA block and the level of fatty acid attached to the polymeric backbone are the major factors affecting micellar properties. An increase in micellar size and reduction in CMC were observed when the level of fatty acid attachment to the polymeric backbone was raised. The elongation of the PLAA block, on the other hand, resulted in an increase in micellar size and core viscosity. Micellar size was the only characteristic being affected by the length of the attached fatty acid. However, a decrease in microviscosity was revealed when behenic acid (22 carbons) was attached to the core-forming block in a high level of substitution. The length of spacer group was also found to be a useful means by which the level of side chain attachment could be controlled. Chemical tailoring of the core structure in polymeric micelles may be used as an efficient means to change micellar properties. As a result, nanoscopic, spherical and stable micelles with improved core properties may be achieved to insure efficient loading and controlled release of an individual drug from the delivery system.
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Lange CF, Hancock RE, Samuel J, Finlay WH. In vitro aerosol delivery and regional airway surface liquid concentration of a liposomal cationic peptide. J Pharm Sci 2001; 90:1647-57. [PMID: 11745723 DOI: 10.1002/jps.1115] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 12/13/2022]
Abstract
A liposome encapsulation was optimized for the entrapment and aerosol delivery of an alpha-helical cationic peptide, CM3, which had shown good antimicrobial and antiendotoxin activity in vitro. The encapsulation procedure and the phospholipids used were selected to maximize both the encapsulation and nebulization efficiencies, without compromising liposomal integrity during nebulization. The best compromise was found with dimyristoyl phosphatidylcholine and dimyristoyl phosphatidylglycerol (3:1 molar ratio), which allowed for peptide encapsulation levels of 730 microg/mL using 30 mM lipid concentration. The aerosol produced with the selected liposomal formulation was subsequently analyzed for determination of size distribution and nebulizer efficiencies. These quantities were used as input for a mathematical lung deposition model, which predicted local lung depositions of the liposomal peptides for three models of lung geometry and breathing patterns: an adult, an 8-year-old child, and a 4-year-old child. The deposition results were then applied to a novel model of airway surface liquid in the lung to assess the concentration of the deposited peptide. The resulting concentration estimates indicate that the minimum inhibitory levels of CM3 can be reached over most part of the tracheobronchial region in the adult model, and can be exceeded throughout the same region in both pediatric model subjects, using a valved jet nebulizer with a 2.5mL volume fill.
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Newman KD, Sosnowski DL, Kwon GS, Samuel J. Delivery of MUC1 mucin peptide by Poly(d,l-lactic-co-glycolic acid) microspheres induces type 1 T helper immune responses. J Pharm Sci 1998; 87:1421-7. [PMID: 9811500 DOI: 10.1021/js980070s] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 11/29/2022]
Abstract
Synthetic peptides corresponding to the variable tandem repeat domain of the cancer-associated antigen MUC1 mucin are candidates for cancer vaccines. In our investigation mice were immunized via subcutaneous injection with poly(d,l-lactic-co-glycolic acid) (PLGA) microspheres containing a MUC1 mucin peptide. It was hypothesized that microencapsulation of the MUC1 mucin peptide would prime for antigen-specific Th1 responses while avoiding the need for traditional adjuvants and carrier proteins. Furthermore, an immunomodulator, monophosphoryl lipid A (MPLA), was incorporated into the peptide-loaded PLGA microspheres based on its ability to enhance Th1 responses. The results revealed T cell specific immune responses. The cytokine secretion profiles of the T cells consisted of high levels of interferon-gamma with undetectable levels of interleukin-4 and interleukin-10. Moreover, incorporation of MPLA in the MUC1 peptide-loaded PLGA microspheres resulted in an increase in interferon-gamma production. The antibody response was negative for IgM and IgG in the absence of MPLA; however, in the presence of MPLA antibody production was negative for IgM with a minimal IgG response consisting of IgG2a, IgG2b, and IgG3. Based on the antibody and cytokine profiles, it was concluded that MUC1 mucin peptide-loaded PLGA microspheres are capable of eliciting specific Th1 responses, which may be enhanced through the use of MPLA.
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Comparative Study |
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Fife MS, Ogilvie EM, Kelberman D, Samuel J, Gutierrez A, Humphries SE, Woo P. Novel IL-6 haplotypes and disease association. Genes Immun 2005; 6:367-70. [PMID: 15815691 DOI: 10.1038/sj.gene.6364186] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 11/09/2022]
Abstract
Interleukin-6 (IL-6) is a pleiotropic cytokine crucial in both adaptive and innate immunity. Numerous genetic studies have shown association with variants of this gene in a multitude of diseases and phenotypes. Most tests of association have focused on a limited set of promoter polymorphisms, in particular, the -174G>C; however, there are many inconsistencies within and between these studies. We propose that there is a more complex regulatory haplotype extending further upstream of the previously characterised promoter region which will provide a more detailed view of the effect of variation on lL-6 regulation. We have exploited two additional single nucleotide polymorphisms (SNPs) in IL-6 that, when examined as a haplotype with existing markers, show an increased level of association with systemic onset juvenile arthritis in a family-based study. This suggests that the haplotype effect may be more functionally relevant to the disease.
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Lavasanifar A, Samuel J, Kwon GS. Micelles of poly(ethylene oxide)-block-poly(N-alkyl stearate L-aspartamide): synthetic analogues of lipoproteins for drug delivery. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2000; 52:831-5. [PMID: 11033567 DOI: 10.1002/1097-4636(20001215)52:4<831::aid-jbm29>3.0.co;2-k] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Academic Contribution Register] [Indexed: 11/07/2022]
Abstract
Stearic acid esters of poly(ethylene oxide)-block-poly(hydroxyethyl L-aspartamide) and poly(ethylene oxide)-block-poly(hydroxyhexyl L-aspartamide) have been synthesized from poly(ethylene oxide)-block-poly(beta-benzyl L-aspartate) by polymer-analogous reactions and self-assembled into a micelle. Transmission electron microscopy and fluorescent probe studies reveal that the micelle mimics structural features of serum lipoproteins: it is nanoscopic, spherical, and has a supramolecular core-shell architecture, where the core is rich in fatty acid esters. As a result, the polymeric micelles effectively solubilize amphotericin B, a key drug for systemic mycoses. Serum lipoproteins solubilize many hydrophobic drugs as a biological transport system besides amphotericin B. A synthetic polymeric analogue may achieve the same aim, but with the ease of structural modification, safety, and stability.
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Padmanabhan TK, Samuel J, Pavithran K, Iyer S, Kuriakose MA, Geeta SN. Comparison of acute toxicities of two chemotherapy schedules for head and neck cancers. J Cancer Res Ther 2006; 2:100-4. [DOI: 10.4103/0973-1482.27584] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 11/04/2022]
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Rosen G, Samuel J, Vered I. Surface tonsillar microflora versus deep tonsillar microflora in recurrent acute tonsillitis. J Laryngol Otol 1977; 91:911-3. [PMID: 925499 DOI: 10.1017/s0022215100084553] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Academic Contribution Register] [Indexed: 12/24/2022]
Abstract
One hundred patients suffering from recurrent acute tonsillitis were studied. One hundred tonsils were cultured. Surface bacteria were compared to deep bacteria. In 48 per cent of the cases a different pathogen was cultured from the interior of the tonsil as compared to the surface culture. This fact may explain recurrence of tonsillitis and makes the reliability of the conventional tonsillar culture questionable. Surgical extirpation of the tonsils seems to be the only treatment since deep bacteria remain unidentified and resist the antibiotic therapy that may affect only the surface microflora.
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Samuel J, Sinha D, Zhao JCG, Wang X. Water residing in small ultrastructural spaces plays a critical role in the mechanical behavior of bone. Bone 2014; 59:199-206. [PMID: 24291421 PMCID: PMC3877214 DOI: 10.1016/j.bone.2013.11.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Academic Contribution Register] [Received: 06/28/2013] [Revised: 10/23/2013] [Accepted: 11/19/2013] [Indexed: 01/23/2023]
Abstract
Water may affect the mechanical behavior of bone by interacting with the mineral and organic phases through two major pathways: i.e. hydrogen bonding and polar interactions. In this study, dehydrated bone was soaked in several solvents (i.e. water, heavy water (D2O), ethylene glycol (EG), dimethylformamide (DMF), and carbon tetrachloride(CCl4)) that are chemically harmless to bone and different in polarity, hydrogen bonding capability and molecular size. The objective was to examine how replacing the original matrix water with the solvents would affect the mechanical behavior of bone. The mechanical properties of bone specimens soaked in these solvents were measured in tension in a progressive loading scheme. In addition, bone specimens without any treatments were tested as the baseline control whereas the dehydrated bone specimens served as the negative control. The experimental results indicated that 22.3±5.17vol% of original matrix water in bone could be replaced by CCl4, 71.8±3.77vol% by DMF, 85.5±5.15vol% by EG, and nearly 100% by D2O and H2O, respectively. CCl4 soaked specimens showed similar mechanical properties with the dehydrated ones. Despite of great differences in replacing water, only slight differences were observed in the mechanical behavior of EG and DMF soaked specimens compared with dehydrated bone samples. In contrast, D2O preserved the mechanical properties of bone comparable to water. The results of this study suggest that a limited portion of water (<15vol% of the original matrix water) plays a pivotal role in the mechanical behavior of bone and it most likely resides in small matrix spaces, into which the solvent molecules larger than 4.0Å cannot infiltrate.
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Research Support, N.I.H., Extramural |
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