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Chugunova E, Gazizov AS, Islamov D, Matveeva V, Burilov A, Akylbekov N, Dobrynin A, Zhapparbergenov R, Appazov N, Chabuka BK, Christopher K, Tonkoglazova DI, Alabugin IV. An Unusual Rearrangement of Pyrazole Nitrene and Coarctate Ring-Opening/Recyclization Cascade: Formal CH-Acetoxylation and Azide/Amine Conversion without External Oxidants and Reductants. Molecules 2023; 28:7335. [PMID: 37959754 PMCID: PMC10648078 DOI: 10.3390/molecules28217335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 10/20/2023] [Accepted: 10/26/2023] [Indexed: 11/15/2023] Open
Abstract
We report an unusual transformation where the transient formation of a nitrene moiety initiates a sequence of steps leading to remote oxidative C-H functionalization (R-CH3 to R-CH2OC(O)R') and the concomitant reduction of the nitrene into an amino group. No external oxidants or reductants are needed for this formal molecular comproportionation. Detected and isolated intermediates and computational analysis suggest that the process occurs with pyrazole ring opening and recyclization.
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Affiliation(s)
- Elena Chugunova
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (A.S.G.); (D.I.); (V.M.); (A.B.); (A.D.); (I.V.A.)
| | - Almir S. Gazizov
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (A.S.G.); (D.I.); (V.M.); (A.B.); (A.D.); (I.V.A.)
| | - Daut Islamov
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (A.S.G.); (D.I.); (V.M.); (A.B.); (A.D.); (I.V.A.)
| | - Victoria Matveeva
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (A.S.G.); (D.I.); (V.M.); (A.B.); (A.D.); (I.V.A.)
| | - Alexander Burilov
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (A.S.G.); (D.I.); (V.M.); (A.B.); (A.D.); (I.V.A.)
| | - Nurgali Akylbekov
- Laboratory of Engineering Profile “Physical and Chemical Methods of Analysis”, Korkyt Ata Kyzylorda University, Aitekebie Str. 29A, Kyzylorda 120014, Kazakhstan; (N.A.); (R.Z.)
| | - Alexey Dobrynin
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (A.S.G.); (D.I.); (V.M.); (A.B.); (A.D.); (I.V.A.)
| | - Rakhmetulla Zhapparbergenov
- Laboratory of Engineering Profile “Physical and Chemical Methods of Analysis”, Korkyt Ata Kyzylorda University, Aitekebie Str. 29A, Kyzylorda 120014, Kazakhstan; (N.A.); (R.Z.)
| | - Nurbol Appazov
- Laboratory of Engineering Profile “Physical and Chemical Methods of Analysis”, Korkyt Ata Kyzylorda University, Aitekebie Str. 29A, Kyzylorda 120014, Kazakhstan; (N.A.); (R.Z.)
- Zhakhaev Kazakh Scientific Research Institute of Rice Growing, Abay Av. 25B, Kyzylorda 120008, Kazakhstan
| | - Beauty K. Chabuka
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-3290, USA; (B.K.C.); (K.C.); (D.I.T.)
| | - Kimberley Christopher
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-3290, USA; (B.K.C.); (K.C.); (D.I.T.)
| | - Daria I. Tonkoglazova
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-3290, USA; (B.K.C.); (K.C.); (D.I.T.)
| | - Igor V. Alabugin
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (A.S.G.); (D.I.); (V.M.); (A.B.); (A.D.); (I.V.A.)
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-3290, USA; (B.K.C.); (K.C.); (D.I.T.)
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Gibadullina E, Neganova M, Aleksandrova Y, Nguyen HBT, Voloshina A, Khrizanforov M, Nguyen TT, Vinyukova E, Volcho K, Tsypyshev D, Lyubina A, Amerhanova S, Strelnik A, Voronina J, Islamov D, Zhapparbergenov R, Appazov N, Chabuka B, Christopher K, Burilov A, Salakhutdinov N, Sinyashin O, Alabugin I. Hybrids of Sterically Hindered Phenols and Diaryl Ureas: Synthesis, Switch from Antioxidant Activity to ROS Generation and Induction of Apoptosis. Int J Mol Sci 2023; 24:12637. [PMID: 37628818 PMCID: PMC10454409 DOI: 10.3390/ijms241612637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 08/03/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023] Open
Abstract
The utility of sterically hindered phenols (SHPs) in drug design is based on their chameleonic ability to switch from an antioxidant that can protect healthy tissues to highly cytotoxic species that can target tumor cells. This work explores the biological activity of a family of 45 new hybrid molecules that combine SHPs equipped with an activating phosphonate moiety at the benzylic position with additional urea/thiourea fragments. The target compounds were synthesized by reaction of iso(thio)cyanates with C-arylphosphorylated phenols containing pendant 2,6-diaminopyridine and 1,3-diaminobenzene moieties. The SHP/urea hybrids display cytotoxic activity against a number of tumor lines. Mechanistic studies confirm the paradoxical nature of these substances which combine pronounced antioxidant properties in radical trapping assays with increased reactive oxygen species generation in tumor cells. Moreover, the most cytotoxic compounds inhibited the process of glycolysis in SH-SY5Y cells and caused pronounced dissipation of the mitochondrial membrane of isolated rat liver mitochondria. Molecular docking of the most active compounds identified the activator allosteric center of pyruvate kinase M2 as one of the possible targets. For the most promising compounds, 11b and 17b, this combination of properties results in the ability to induce apoptosis in HuTu 80 cells along the intrinsic mitochondrial pathway. Cyclic voltammetry studies reveal complex redox behavior which can be simplified by addition of a large excess of acid that can protect some of the oxidizable groups by protonations. Interestingly, the re-reduction behavior of the oxidized species shows considerable variations, indicating different degrees of reversibility. Such reversibility (or quasi-reversibility) suggests that the shift of the phenol-quinone equilibrium toward the original phenol at the lower pH may be associated with lower cytotoxicity.
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Affiliation(s)
- Elmira Gibadullina
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (M.N.); (Y.A.); (A.V.); (M.K.); (A.L.); (S.A.); (A.S.); (A.B.); (O.S.); (I.A.)
| | - Margarita Neganova
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (M.N.); (Y.A.); (A.V.); (M.K.); (A.L.); (S.A.); (A.S.); (A.B.); (O.S.); (I.A.)
- Institute of Physiologically Active Compounds at Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Severnij Pr. 1, Chernogolovka 142432, Russia;
| | - Yulia Aleksandrova
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (M.N.); (Y.A.); (A.V.); (M.K.); (A.L.); (S.A.); (A.S.); (A.B.); (O.S.); (I.A.)
- Institute of Physiologically Active Compounds at Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Severnij Pr. 1, Chernogolovka 142432, Russia;
| | - Hoang Bao Tran Nguyen
- The Department of General Organic and Petrochemical Synthesis Technology, The Kazan National Research Technological University, Karl Marx St. 68, Kazan 420015, Russia; (H.B.T.N.); (T.T.N.)
| | - Alexandra Voloshina
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (M.N.); (Y.A.); (A.V.); (M.K.); (A.L.); (S.A.); (A.S.); (A.B.); (O.S.); (I.A.)
| | - Mikhail Khrizanforov
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (M.N.); (Y.A.); (A.V.); (M.K.); (A.L.); (S.A.); (A.S.); (A.B.); (O.S.); (I.A.)
| | - Thi Thu Nguyen
- The Department of General Organic and Petrochemical Synthesis Technology, The Kazan National Research Technological University, Karl Marx St. 68, Kazan 420015, Russia; (H.B.T.N.); (T.T.N.)
| | - Ekaterina Vinyukova
- Institute of Physiologically Active Compounds at Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Severnij Pr. 1, Chernogolovka 142432, Russia;
| | - Konstantin Volcho
- Department of Medicinal Chemistry, Novosibirsk Institute of Organic Chemistry, Lavrentiev Av. 9, Novosibirsk 630090, Russia (D.T.); (N.S.)
| | - Dmitry Tsypyshev
- Department of Medicinal Chemistry, Novosibirsk Institute of Organic Chemistry, Lavrentiev Av. 9, Novosibirsk 630090, Russia (D.T.); (N.S.)
| | - Anna Lyubina
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (M.N.); (Y.A.); (A.V.); (M.K.); (A.L.); (S.A.); (A.S.); (A.B.); (O.S.); (I.A.)
| | - Syumbelya Amerhanova
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (M.N.); (Y.A.); (A.V.); (M.K.); (A.L.); (S.A.); (A.S.); (A.B.); (O.S.); (I.A.)
| | - Anna Strelnik
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (M.N.); (Y.A.); (A.V.); (M.K.); (A.L.); (S.A.); (A.S.); (A.B.); (O.S.); (I.A.)
| | - Julia Voronina
- Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninskii Prospekt, 31, Moscow 119071, Russia;
| | - Daut Islamov
- Laboratory for Structural Analysis of Biomacromolecules, Kazan Scientific Center of Russian Academy of Science, 31, Kremlevskaya, Kazan 420008, Russia;
| | - Rakhmetulla Zhapparbergenov
- Laboratory of Engineering Profile, Department of Engineering Technology, Korkyt Ata Kyzylorda University, 29A, Aiteke Bi Street, Kyzylorda 120014, Kazakhstan;
| | - Nurbol Appazov
- Laboratory of Engineering Profile, Department of Engineering Technology, Korkyt Ata Kyzylorda University, 29A, Aiteke Bi Street, Kyzylorda 120014, Kazakhstan;
| | - Beauty Chabuka
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-3290, USA; (B.C.)
| | - Kimberley Christopher
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-3290, USA; (B.C.)
| | - Alexander Burilov
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (M.N.); (Y.A.); (A.V.); (M.K.); (A.L.); (S.A.); (A.S.); (A.B.); (O.S.); (I.A.)
| | - Nariman Salakhutdinov
- Department of Medicinal Chemistry, Novosibirsk Institute of Organic Chemistry, Lavrentiev Av. 9, Novosibirsk 630090, Russia (D.T.); (N.S.)
| | - Oleg Sinyashin
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (M.N.); (Y.A.); (A.V.); (M.K.); (A.L.); (S.A.); (A.S.); (A.B.); (O.S.); (I.A.)
| | - Igor Alabugin
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov St. 8, Kazan 420088, Russia; (M.N.); (Y.A.); (A.V.); (M.K.); (A.L.); (S.A.); (A.S.); (A.B.); (O.S.); (I.A.)
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-3290, USA; (B.C.)
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Massa S, Osazuwa-Peters N, Christopher K, Walker R, Varvares M. Comparison of Head and Neck Cancer Populations by Cause of Death. Int J Radiat Oncol Biol Phys 2016. [DOI: 10.1016/j.ijrobp.2015.12.317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Massa S, Osazuwa-Peters N, Christopher K, Walker R, Varvares M. Cancer-Independent Loss of Life Expectancy in the Head and Neck Cancer Population. Int J Radiat Oncol Biol Phys 2016. [DOI: 10.1016/j.ijrobp.2015.12.325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Riviello ED, Wang KC, Hochman ME, Sariban A, Da Rocha RC, Dogaru G, Christopher K. Vacuolization of tubules in gadolinium-associated acute renal failure. Rev Med Chir Soc Med Nat Iasi 2009; 113:108-115. [PMID: 21491811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
While gadolinium was initially thought to be a safe alternative to iodinated contrast agents for patients with chronic renal insufficiency, many reports of gadolinium-associated acute renal failure have now been recorded, particularly in patients with underlying renal insufficiency. In addition, animal models have demonstrated tubule vacuolization with experimental gadolinium administration that is similar to vacuolization seen with other contrast agents. We present a case of a patient with nephrotic-range proteinuria and chronic renal insufficiency, who developed acute renal failure following gadolinium administration undergoing furosemide stimulated diuresis. This case is the first report of pathologic tubule vacuolization in gadolinium-associated nephropathy in a human kidney biopsy. This case suggests a relationship between the pathogenesis of CIN with standard contrast media and CIN with gadolinium. Research is needed to better understand the pathologic findings and pathogenesis of gadolinium-associated nephrotoxicity.
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Affiliation(s)
- Elisabeth D Riviello
- Department of Medicine, Renal Division, Harvard Medical School, Brigham and Women's Hospital, Boston, USA
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Chahin N, Christopher K, Mandrekar J, Sorenson E. 98. The natural history of spinobulbar muscular atrophy. Clin Neurophysiol 2008. [DOI: 10.1016/j.clinph.2007.11.148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Christopher K, Mueller TF, Liang Y, Finn PW, Perkins DL. Modulation of gene expression by alloimmune networks following murine heart transplantation. Mol Genet Genomics 2004; 271:687-96. [PMID: 15138889 DOI: 10.1007/s00438-004-1013-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2004] [Accepted: 03/31/2004] [Indexed: 11/24/2022]
Abstract
The objective of our study was to analyze gene expression profiles in a complex in vivo model of solid organ transplantation, and to investigate the effects of single-gene deletions on alloimmunity. Using algorithms to generate dendrograms and self-organizing maps, we differentiated the alloimmune profiles of 16 transgenic knockout mouse strains, and identified subsets of genes that correlate with the duration of graft survival and provide candidates for prognostic and diagnostic indicators following transplantation in our model system.
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Affiliation(s)
- K Christopher
- Laboratory of Molecular Immunology, Renal Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, PBB 170, Boston, MA 02115, USA
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Christopher K, Hong M, Yodice PC. Vitamin K deficiency in diffuse alveolar hemorrhage associated with systemic lupus erythematosus. Respiration 2002; 68:658. [PMID: 11786727 DOI: 10.1159/000050591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Abstract
Oculopharyngeal muscular dystrophy (OPMD) is an uncommon autosomal dominant disorder characterized by late onset and slow progression. Complications of OPMD include ptosis and progressive dysphagia leading to eventual malnutrition and aspiration. We report a rare case of OPMD complicating mechanical ventilator management following emergent surgery. OPMD and the resulting dysphagia contributed to multiple intubations, tracheostomy, aspiration pneumonia, and a prolonged hospital course. Awareness of the possibility of OPMD in intubated patients with a history of dysphagia is crucial for avoidance of complications.
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Affiliation(s)
- K Christopher
- Division of Critical Care Medicine, the Miriam Hospital, Brown University School of Medicine, Providence, RI 02906, USA.
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Bostom AG, Shemin D, Bagley P, Massy ZA, Zanabli A, Christopher K, Spiegel P, Jacques PF, Dworkin L, Selhub J. Controlled comparison of L-5-methyltetrahydrofolate versus folic acid for the treatment of hyperhomocysteinemia in hemodialysis patients. Circulation 2000; 101:2829-32. [PMID: 10859289 DOI: 10.1161/01.cir.101.24.2829] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The hyperhomocysteinemia regularly found in hemodialysis patients is largely refractory to combined oral B-vitamin supplementation featuring supraphysiological doses of folic acid. We evaluated whether a high-dose L-5-methyltetrahydrofolate-based regimen provided improved total homocysteine (tHcy)-lowering efficacy in chronic hemodialysis patients. METHODS AND RESULTS We block-randomized 50 chronic, stable hemodialysis patients on the basis of their screening predialysis tHcy levels, sex, and dialysis center into 2 groups of 25 subjects treated for 12 weeks with oral folic acid at 15 mg/d (FA group) or an equimolar amount (17 mg/d) of oral L-5-methyltetrahydrofolate (MTHF group). All 50 subjects also received 50 mg/d of oral vitamin B(6) and 1.0 mg/d of oral vitamin B(12). The mean percent reductions (+/-95% CIs) in predialysis tHcy were not significantly different: MTHF, 17.0% (12.0% to 22.0%); FA, 14.8% (9.6% to 20.1%); P=0.444 by matched ANCOVA adjusted for pretreatment tHcy. Final on-treatment values (mean with 95% CI) were MTHF, 20.0 micromol/L (18.8 to 21.2 micromol/L); FA, 19.5 micromol/L (18.3 to 20.7 micromol/L). Moreover, neither treatment resulted in "normalization" of tHcy levels (ie, final on-treatment values <12 micromol/L) among a significantly different or clinically meaningful number of patients: MTHF, 2 of 25 (8%); FA, 0 of 25 (0%); Fisher's exact test of between-groups difference, P=0.490. CONCLUSIONS Relative to high-dose folic acid, high-dose oral L-5-methyltetrahydrofolate-based supplementation does not afford improved tHcy-lowering efficacy in hemodialysis patients. The preponderance of hemodialysis patients (ie, >90%) exhibit mild hyperhomocysteinemia refractory to treatment with either regimen. This treatment refractoriness is not related to defects in folate absorption or circulating plasma and tissue distribution.
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Affiliation(s)
- A G Bostom
- Division of General Internal Medicine, Memorial Hospital of Rhode Island, Pawtucket 02860, USA.
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Christopher K, Gamouras G, Matfin G. Respiratory distress, weakness, and electrolyte abnormalities. Hosp Pract (1995) 1996; 31:20-2. [PMID: 8969676 DOI: 10.1080/21548331.1996.11443386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A 56-year old man was admitted to the hospital with malaise, weakness, and fatigue. He was short of breath and had bilateral foot edema. Even though he had been very active a month earlier, he could no longer climb stairs. For the last two weeks, he had had a cough producing green sputum, a "tight feeling" in his chest, polyuria, and polydipsia. He had not had radiating chest pain, palpitations, leg pain or erythema, hemoptysis, diaphoresis, flushing, fever, chills, nausea, vomiting, diarrhea, or a loud snore.
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Christopher K, Chang J, Goldberg J. Stimulation of cilia beat frequency by serotonin is mediated by a Ca2+ influx in ciliated cells of Helisoma trivolvis embryos. J Exp Biol 1996; 199:1105-13. [PMID: 9318930 DOI: 10.1242/jeb.199.5.1105] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Serotonin (5-HT) has been established as a regulator of ciliary beating in numerous systems. In early embryos of Helisoma trivolvis, a cilia-driven rotational movement is modulated by the release of endogenous serotonin from a pair of embryonic neurons, ENC1s, directly onto the ciliated epithelium. The present study was undertaken to examine the signal transduction mechanisms underlying serotonin-mediated cilio-excitation in Helisoma trivolvis embryos. Using time-lapse videomicroscopy, the ciliary beat frequency (CBF) of cultured embryonic ciliated cells was measured in response to various pharmacological manipulations. Serotonin increased CBF in a dose-dependent manner. Addition of 8-bromo-cyclic AMP, isobutylmethylxanthine (IBMX) or a combination of forskolin and IBMX, treatments that elevate the concentration of intracellular cyclic AMP, did not mimic the serotonin-induced increase in CBF. Thus, cyclic AMP does not appear to be involved in the regulation of CBF in this system. In contrast, depolarizing the cells with KCl or veratridine, and artificially raising the intracellular Ca2+ concentration with thapsigargin or A23187, caused a serotonin-like increase in CBF. Furthermore, the serotonin response was abolished in a Ca2+-depleted medium or in a medium containing the L-type Ca2+ channel blockers verapamil or nifedipine. These results suggest that serotonin-stimulated cilio-excitation in cultured Helisoma trivolvis cells involves an influx of Ca2+ to increase intracellular Ca2+ concentration. The link between serotonin-receptor binding and Ca2+ influx in these cells has yet to be determined.
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Christopher K. The problem with quality. Hosp Trustee 1991; 15:7. [PMID: 10114413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Campbell D, Christopher K. The evolution of a patient satisfaction survey. Dimens Health Serv 1991; 68:18-20. [PMID: 2019330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- D Campbell
- Rehabilitation Services, Ottawa Civic Hospital
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Abstract
We studied 68 chronic asthmatic patients, 18 to 76 yr of age, with a percent predicted FEV1 between 33 and 81, comparing cromolyn sodium with placebo. We used a double-blind, comparative group trial design. A 4-wk baseline period was followed by 3 months of active treatment or placebo. Patients recorded symptom severity and frequency of study drug and concomitant medication usage on daily diary cards. At each clinic visit, patients independently assessed the effectiveness of the test medication in controlling their asthma. Physicians also assessed the severity of the patients' symptoms, pulmonary function, and effectiveness of test medication at monthly intervals. Methacholine challenges were done pre- and post-treatment. Use of concomitant therapy was reduced according to a specified schedule. There was significant improvement in the severity of daytime asthma, nighttime asthma, and cough as assessed by the patients in the cromolyn sodium group. Mean use of concomitant medications decreased significantly in cromolyn sodium patients. Despite the reductions in the use of bronchodilators, pulmonary function (FEV1, FVC, FEF25-75) improved significantly in the cromolyn sodium group. Similar improvements did not occur in the control group. The physicians' assessments of symptoms showed significant improvement in favor of the cromolyn sodium group. Both physicians and patients judged cromolyn sodium to be moderately or very effective for 61% of the patients as compared to 27% (by physicians) and 24% (by patients) in the placebo group. There was no significant difference in methacholine response between the two groups, although the mean value for methacholine sensitivity in the cromolyn sodium group was significantly less at the end of the study than at baseline.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- T L Petty
- Webb-Waring Lung Institute, University of Colorado Health Sciences Center, Denver
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Berger GM, Christopher K, Juritz JM, Liesegang F. Accuracy and reproducibility of cholesterol assay in the western Cape. S Afr Med J 1988; 74:490-5. [PMID: 3187799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The accuracy and precision of cholesterol assay in the western Cape region is reported. The survey was carried out over 15 weeks utilising three human EDTA plasma pools with normal, borderline high and high cholesterol levels respectively. All 11 laboratories in the region providing a service to academic, provincial or military hospitals or to the private medical sector were included in the study. Ten of the 11 laboratories utilised automated enzymatic methods of cholesterol assay whereas 1 used a manual procedure based on the Liebermann-Burchard reaction. Methods were standardised by means of a variety of commercial calibrator material in all except 1 laboratory which used reference sera from the Centers for Disease Control, Atlanta. The performance of the 4 best laboratories met the standard of precision recommended for cholesterol assay, viz. total coefficient of variation of less than or equal to 2.5%. However, only 2 of the 11 laboratories achieved the optimum objective of an overall bias of less than 2.0% together with precision of less than or equal to 2.5%. Rational use of cholesterol assay for diagnosis and management will therefore require standardisation of cholesterol assay on a common reference material and greater attention to analytical factors influencing the reproducibility of results. Intrinsic biological variation also contributes uncertainty to the interpretation of a single value. Thus important clinical decisions must be based on two or more assays carried out using appropriate methodology.
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Affiliation(s)
- G M Berger
- Department of Chemical Pathology, Red Cross War Memorial Children's Hospital, Cape Town
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Hegstrom T, Emmons LL, Hoddes E, Kennedy T, Christopher K, Collins T, Spofford B. Obstructive sleep apnea syndrome: preoperative radiologic evaluation. AJR Am J Roentgenol 1988; 150:67-9. [PMID: 3257133 DOI: 10.2214/ajr.150.1.67] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The purpose of this study was to determine whether lateral radiographs of the pharynx and fluoroscopy of the lateral pharynx in the sleeping patient could be used as predictors of surgical success in patients undergoing soft-palate surgery for obstructive sleep apnea. A total of 12 patients had surgery after radiologic evaluation. There were six surgical successes and six failures. No successes occurred in patients with a soft-palate length of less than 46 mm, nor were there any successes among patients whose initial point of obstruction on fluoroscopy was inferior to the level of the soft palate. There was one surgical failure among patients in whom fluoroscopy showed upper airway obstruction beginning at the level of the soft palate during sleep. Results suggest that a patient is most likely to benefit from soft-palate resection if the soft palate is long--we conservatively suggest greater than 40 mm--and if sleep fluoroscopy of the lateral pharynx shows airway obstruction beginning at the level of the soft palate.
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Affiliation(s)
- T Hegstrom
- Department of Radiology, AMI/Presbyterian Denver Medical Center, CO 80218
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Selner JC, Staudenmayer H, Koepke JW, Harvey R, Christopher K. Vocal cord dysfunction: the importance of psychologic factors and provocation challenge testing. J Allergy Clin Immunol 1987; 79:726-33. [PMID: 3571766 DOI: 10.1016/0091-6749(87)90203-x] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We present three case reports involving patients with vocal cord dysfunction. The onset of symptoms in one case was coincident with a generalized cutaneous reaction to penicillin with laryngeal involvement. The other cases had been misdiagnosed as food allergy and chemical sensitivity. We describe the psychologic factors in these cases in terms of the primary and secondary gain operative in the somatoform disorder of conversion reaction and emphasize the importance of belief and learned sensitivity in the induction of symptoms. The necessity of considering psychologic factors and the use of blinded, controlled, provocation challenges to evaluate subjective symptomatology is underscored. This study emphasizes the heterogenicity of clinical presentations involving vocal cord dysfunction and illustrates the value of fiberoptic-assisted examination of laryngeal function in conjunction with provocation challenge testing in establishing causal relationships for specific clinical symptoms.
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Christopher K. Managing people: meeting the challenge. Part 2. Dimens Health Serv 1986; 63:34-5. [PMID: 3710010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Christopher K. Managing people: tips for mastering the art. Part 1. Dimens Health Serv 1986; 63:38. [PMID: 3699296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Christopher K. Striving for excellence--gaining personal commitment. Part 2. Dimens Health Serv 1985; 62:30, 40. [PMID: 4076570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Christopher K. Striving for excellence--unlocking staff potential. Part 1. Dimens Health Serv 1985; 62:39. [PMID: 3987986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Irwing GA, Christopher K. Inaccurate tourniquet pressure-gauge readings--a widespread problem. S Afr Med J 1984; 66:265-6. [PMID: 6463803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Complications due to inaccurate pneumatic tourniquet pressure-gauge readings have been well described. However, no standard protocol for regular testing of the tourniquet apparatus, especially at the pressures used in clinical practice, appears to have been developed. We therefore developed a protocol for testing the Kidde pneumatic tourniquet apparatus and used this protocol to test 13 apparatuses in regular use at several hospitals in the Western Cape. We found that 8 of the apparatuses checked were inaccurate by as much as 350 mmHg, 8 had defective valves and 1 was considered to be too dangerous for further clinical use. This random survey shows that the majority of pneumatic tourniquet apparatuses in clinical use may be inaccurate and that more frequent testing and appropriate maintenance are indicated.
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Murty A, Ramani A, Christopher K, Rajabhushanam B. Toxicity of methyl parathion and fensulfothion to the fish Mystus cavasius. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/0143-1471(84)90087-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Murty AS, Rajabhushanam BR, Christopher K, Ramani AV. Improved Ammonium Molybdate Method for Thin Layer Chromatographic Detection of Organophosphate Residues. J AOAC Int 1980. [DOI: 10.1093/jaoac/63.4.756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
An improved ammonium molybdate method for detecting organophosphate residues on thin layer chromatographic (TLC) plates is described. After development, the plates are heated at 110°C for 2 h and the resultant inorganic phosphate is reacted with ammonium molybdate to form phosphomolybdate which is then reduced to a blue complex by ascorbic acid. Quantities as low as 0.1–0.2 μg residues could be detected on TLC plates by this method.
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Affiliation(s)
| | | | - K Christopher
- Nagarjuna University, Department of Zoology, Nagarjuna Nagar 522 510, S. India
| | - A Venkata Ramani
- Nagarjuna University, Department of Zoology, Nagarjuna Nagar 522 510, S. India
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