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1.
J Laryngol Otol ; : 1-5, 2020 Jan 23.
Article in English | MEDLINE | ID: mdl-31969202

ABSTRACT

OBJECTIVES: Understanding the pattern of middle-ear cholesteatoma becomes pertinent with the rise of endoscopic surgery as surgeons decide on the optimal approach to visualise and extirpate disease. With modifications to the Telmesani attic-tympanum-mastoid staging system, this study aimed to evaluate the commonest patterns of middle-ear cholesteatoma and their implications for surgical approach. METHODS: A retrospective study was conducted in a single tertiary institution in Singapore. All patients undergoing cholesteatoma surgery between January 2012 and June 2015 were included. Staging of cholesteatoma was based on clinical assessment corroborated by radiological findings. RESULTS: Out of the 55 ears included, 98.2 per cent had cholesteatoma involving the attic. The disease extended into the mastoid antrum and beyond in 43 cases (78.2 per cent). The facial recess and/or sinus tympanum was affected in 26 cases (47.3 per cent). CONCLUSION: The majority of cholesteatoma cases present with extensive attic disease and significant mastoid involvement. In these cases, endoscopes may be best suited to adjunctive rather than exclusive use in surgery.

3.
Cell Death Dis ; 5: e1305, 2014 Jun 26.
Article in English | MEDLINE | ID: mdl-24967967

ABSTRACT

An alternative antimalarial pathway of an 'outdated' drug, chloroquine (CQ), may facilitate its return to the shrinking list of effective antimalarials. Conventionally, CQ is believed to interfere with hemozoin formation at nanomolar concentrations, but resistant parasites are able to efflux this drug from the digestive vacuole (DV). However, we show that the DV membrane of both resistant and sensitive laboratory and field parasites is compromised after exposure to micromolar concentrations of CQ, leading to an extrusion of DV proteases. Furthermore, only a short period of exposure is required to compromise the viability of late-stage parasites. To study the feasibility of this strategy, mice malaria models were used to demonstrate that high doses of CQ also triggered DV permeabilization in vivo and reduced reinvasion efficiency. We suggest that a time-release oral formulation of CQ may sustain elevated blood CQ levels sufficiently to clear even CQ-resistant parasites.


Subject(s)
Antimalarials , Chloroquine , Malaria/drug therapy , Plasmodium/metabolism , Animals , Antimalarials/pharmacokinetics , Antimalarials/pharmacology , Chloroquine/pharmacokinetics , Chloroquine/pharmacology , Disease Models, Animal , Drug Evaluation , Hemeproteins/metabolism , Malaria/blood , Mice , Mice, Inbred BALB C
4.
Cell Death Dis ; 2: e216, 2011 Oct 13.
Article in English | MEDLINE | ID: mdl-21993392

ABSTRACT

Having previously characterized chloroquine (CQ)-induced programmed cell death (PCD) hallmarks in the malaria parasite Plasmodium falciparum and delineating a pathway linking these features, the roles of non-classical mediators were investigated in this paper. It was shown that the later stages of this pathway are Ca(2+)-dependent and transcriptionally regulated. Moreover, it was demonstrated for the first time that micromolar concentrations of CQ partially permeabilized the parasite's digestive vacuole (DV) membrane and that this important upstream event appears to precede mitochondrial dysfunction. This permeabilization of the DV occurred without rupture of the DV membrane and was reminiscent of lysosome-mediated cell death in mammalian cells. As such micromolar concentrations of CQ are found in the patient's plasma after initial CQ loading, this alludes to a clinically relevant antimalarial mechanism of the drug which has yet to be recognized. Furthermore, other 'non-antimalarial' lysosomotropic compounds were also shown to cause DV permeabilization, triggering PCD in both CQ-sensitive and -resistant parasites. These findings present new avenues for antimalarial developments, which induce DV destabilization to kill parasites.


Subject(s)
Antimalarials/pharmacology , Chloroquine/pharmacology , Plasmodium falciparum/drug effects , Plasmodium falciparum/metabolism , Vacuoles/drug effects , Animals , Dose-Response Relationship, Drug , Membrane Potential, Mitochondrial/drug effects , Microscopy, Electron , Plasmodium falciparum/cytology , Protein Array Analysis , Signal Transduction , Vacuoles/metabolism
5.
Cell Death Dis ; 1: e26, 2010.
Article in English | MEDLINE | ID: mdl-21364634

ABSTRACT

Several recent discoveries of the hallmark features of programmed cell death (PCD) in Plasmodium falciparum have presented the possibility of revealing novel targets for antimalarial therapy. Using a combination of cell-based assays, flow cytometry and fluorescence microscopy, we detected features including mitochondrial dysregulation, activation of cysteine proteases and in situ DNA fragmentation in parasites induced with chloroquine (CQ) and staurosporine (ST). The use of the pan-caspase inhibitor, z-Val-Ala-Asp-fmk (zVAD), and the mitochondria outer membrane permeabilization (MOMP) inhibitor, 4-hydroxy-tamoxifen, enabled the characterization of a novel CQ-induced pathway linking cysteine protease activation to downstream mitochondrial dysregulation, amplified protease activity and DNA fragmentation. The PCD features were observed only at high (µM) concentrations of CQ. The use of a new synthetic coumarin-labeled chloroquine (CM-CQ) showed that these features may be associated with concentration-dependent differences in drug localization. By further using cysteine protease inhibitors z-Asp-Glu-Val-Asp-fmk (zDEVD), z-Phe-Ala-fmk (zFA), z-Phe-Phe-fmk (zFF), z-Leu-Leu-Leu-fmk (zLLL), E64d and CA-074, we were able to implicate clan CA cysteine proteases in CQ-mediated PCD. Finally, CQ induction of two CQ-resistant parasite strains, 7G8 and K1, reveals the existence of PCD features in these parasites, the extent of which was less than 3D7. The use of the chemoreversal agent verapamil implicates the parasite digestive vacuole in mediating CQ-induced PCD.


Subject(s)
Apoptosis , Cysteine Proteases/metabolism , Malaria/parasitology , Mammals/metabolism , Parasites/cytology , Plasmodium falciparum/cytology , Protozoan Proteins/metabolism , Animals , Apoptosis/drug effects , Calcium/metabolism , Chloroquine/pharmacology , DNA/metabolism , DNA Fragmentation/drug effects , Dose-Response Relationship, Drug , Fluorescent Dyes/metabolism , Intracellular Space/drug effects , Intracellular Space/metabolism , Membrane Potential, Mitochondrial/drug effects , Models, Biological , Necrosis , Parasites/drug effects , Parasites/enzymology , Plasmodium falciparum/drug effects , Plasmodium falciparum/enzymology , Reproducibility of Results , Signal Transduction/drug effects , Staining and Labeling , Time Factors
6.
Health Serv Res ; 36(6 Pt 1): 1085-107, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11775669

ABSTRACT

OBJECTIVE: The burden of illness can influence treatment decisions, but there are limited data comparing the performance of different illness burden measures. We assessed the correlations between five previously validated measures of illness burden and global health and physical function and evaluated how each measure correlates with breast cancer treatment patterns in older women. DATA SOURCE: A cohort of 718 women > 67 years with early-stage breast cancer formed the study group. STUDY DESIGN/DATA COLLECTION METHODS: The study made a cross-sectional comparison of illness burden measures (Charlson index, Index of Co-existent Diseases, cardiopulmonary burden of illness, patient-specific life expectancy, and disease counts) and physical function and self-rated global health status. Data were collected from records and patient interviews. PRINCIPAL FINDINGS: All of the measures were significantly correlated with each other and with physical function and self-rated health (p < .001). After controlling for age and stage, life expectancy had the largest effect on surgical treatment, followed by self-rated physical function and health; life expectancy was also independent of physical function. For instance, women with higher life expectancy and better self-rated physical function and health were more likely to receive breast conservation and radiation than sicker women. Women with higher physical functioning were more likely to receive adjuvant chemotherapy than women with lower functioning. CONCLUSIONS: Several measures of illness burden were associated with breast cancer therapy, but each measure accounted for only a small amount of variance in treatment patterns. Future work is needed to develop and validate measures of burden of illness that are feasible, comprehensive, and relevant for diverse clinical and health services objectives.


Subject(s)
Activities of Daily Living , Breast Neoplasms/epidemiology , Breast Neoplasms/therapy , Cost of Illness , Disabled Persons/statistics & numerical data , Health Status , Severity of Illness Index , Women's Health , Age Distribution , Age Factors , Aged , Attitude to Health , Breast Neoplasms/classification , Breast Neoplasms/psychology , Comorbidity , Cross-Sectional Studies , Disabled Persons/classification , Disabled Persons/psychology , District of Columbia/epidemiology , Female , Geriatric Assessment , Humans , Life Expectancy , Massachusetts/epidemiology , New York/epidemiology , Surveys and Questionnaires , Texas/epidemiology , Treatment Outcome
7.
Int J Cancer ; 88(1): 135-8, 2000 Oct 01.
Article in English | MEDLINE | ID: mdl-10962451

ABSTRACT

Oestrogen is important in the development of breast cancer. Oestrogen receptor positive breast cancers are associated with a better prognosis than oestrogen-receptor negative breast cancers since they are more responsive to hormonal treatment. Oestrone sulphate acts as a huge reservoir for oestrogens in the breast. It is converted to the potent oestrogen, oestradiol (E(2)) by the enzymes oestrone sulphatase and oestradiol-17beta hydroxysteroid dehydrogenase (E(2)DH). Retinoic acid and carotenoids have been shown to have chemopreventive activity against some cancers. The aim of our study was to determine and compare the effects of retinoic acid and palm oil carotenoids on growth of and oestrone sulphatase and E(2)DH activities in the oestrogen receptor positive, MCF-7 and oestrogen receptor negative, MDA-MB-231 breast cancer cell lines. Retinoic acid and carotenoids inhibited MCF-7 cell growth but had no effect on MDA-MB-231 cell growth. Both retinoic acid and carotenoids stimulated oestrone sulphatase activity in the MCF-7 cell line. E(1) to E(2) conversion was inhibited by 10(-7) M carotenoids but was stimulated at 10(-6) M in the MCF-7 cell line. Retinoic acid had no effect on E(1) to E(2) conversion at 10(-7) M but stimulated E(1) to E(2) conversion at 10(-6) M. Retinoic acid and carotenoids had no effect on E(2) to E(1) conversion in the MCF-7 cell line. Retinoic acid stimulated E(1) to E(2) conversion in the MDA-MB-231 cell line but had no effect on oestrone sulphatase activity or E(2) to E(1) conversion in this cell line. Both oestrone sulphatase and E(2)DH activity were not affected by carotenoids in the MDA-MB-231 cell line. In conclusion, retinoic acid and carotenoids may prevent the development of hormone-dependent breast cancers since they inhibit the growth of the MCF-7 cell line.


Subject(s)
Antineoplastic Agents/pharmacology , Breast Neoplasms/enzymology , Carotenoids/pharmacology , Estradiol Dehydrogenases/metabolism , Plant Oils/pharmacology , Sulfatases/metabolism , Breast Neoplasms/pathology , Cell Division/drug effects , Dose-Response Relationship, Drug , Female , Humans , Palm Oil , Receptors, Estrogen/physiology , Tretinoin/pharmacology , Tumor Cells, Cultured
8.
J Thorac Cardiovasc Surg ; 119(4 Pt 1): 720-31, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10733760

ABSTRACT

OBJECTIVE: To examine the survival, developmental status, quality of life, and direct medical costs of children with hypoplastic left heart syndrome who have undergone stage I, II, and III reconstructive surgery. METHODS: A total of 106 children underwent staged repair for classic hypoplastic left heart syndrome between February 1990 and March 1999 (stage I: 106; stage II: 49; stage III: 25; 4 converted to heart transplantation). Survival was analyzed by the Kaplan-Meier method. In a cross-sectional study, parents assessed quality of life by completing the Infant/Toddler Child Health Questionnaire or Child Health Questionnaire Parent Format-28; they assessed developmental progress by completing the Ages and Stages Questionnaire. The ratio-of-costs-to-charges method was used to derive hospital costs, and payments were used to capture physician time and wholesale pricing for outpatient medications. RESULTS: Institutional 1-year and 5-year actuarial survivals were 58% and 54%. Birth weight, the need for preoperative inotropic drugs, and surgical experience were predictors of survival. Norwood I patients achieved fewer developmental benchmarks than those who survived to subsequent stages. Child Health Questionnaire Parent Format-28 mean summary scores for physical and psychosocial health were 48.5 +/- 6.3 and 42.8 +/- 9.9. The median inpatient costs for stage I, II, and III repairs were $51,000, $33,892, and $52,183, respectively. Monthly outpatient and readmission costs were less than 10% of total costs. CONCLUSION: A prospective, large-scale study of the comprehensive outcomes of staged repair and transplantation is needed. This study will need to address the longer-term developmental and quality-of-life outcomes, as well as the long-term cost effectiveness of these procedures.


Subject(s)
Hypoplastic Left Heart Syndrome/mortality , Hypoplastic Left Heart Syndrome/surgery , Child Development , Female , Health Care Costs , Humans , Hypoplastic Left Heart Syndrome/economics , Infant , Infant, Newborn , Male , Quality of Life , Surveys and Questionnaires , Survival Rate
9.
J Nat Prod ; 57(4): 486-93, 1994 Apr.
Article in English | MEDLINE | ID: mdl-8021648

ABSTRACT

Bioactive Annonaceous acetogenins have been isolated from the EtOH extract of the bark of Xylopia aromatica by bioactivity-directed fractionation using lethality to brine shrimp. These acetogenins include xylopianin [1 , xylopiacin [2], and xylomaticin [3], which are three new mono-tetrahydrofuran ring type acetogenins, in addition to the known compounds, annomontacin, gigantetronenin, gigantetrocin A, and annonacin. Compounds 1 and 2 are unusual in having hydroxylation at C-8; 3 has the same functionalities as annonacin but with 37 carbons instead of 35 carbons. The structures were elucidated by spectral analysis of the parent compounds and/or simple chemical derivatives. These acetogenins showed cytotoxicities, comparable to adriamycin, against three human solid tumor cell lines.


Subject(s)
Antineoplastic Agents, Phytogenic/isolation & purification , Furans/isolation & purification , Plants, Medicinal/chemistry , Animals , Antineoplastic Agents, Phytogenic/pharmacology , Artemia , Doxorubicin/pharmacology , Drug Screening Assays, Antitumor , Furans/pharmacology , Gas Chromatography-Mass Spectrometry , Humans , Magnetic Resonance Spectroscopy , Molecular Conformation , Tumor Cells, Cultured , Venezuela
10.
J Chromatogr Sci ; 26(9): 463-9, 1988 Sep.
Article in English | MEDLINE | ID: mdl-3225310

ABSTRACT

Palm oil carotenoids are analyzed by nonaqueous reversed-phase high-performance liquid chromatography (NARP-HPLC) with UV/vis diode-array detection. Isocratic elution with 60% acetonitrile/35% methanol/5% methylene chloride at 2 mL/min on a 25-cm C18 column results in an analysis time of 30 min. Identification is made through absorption spectra and chromatographic elution behaviors, for example, polyenic pi conjugation, dipole moment of end-groups, and oxygen function on the chromophores. At least 12 carotenoids are identified with alpha- and beta-carotene as the dominant carotenoids (1:2 ratio). Several mono- and di-epoxides of alpha- and beta-isomers and hydrocarbon carotenes are found, including the UV-absorbing phytoene identified by spectral substraction. cis-Isomerization is found and discussed in the light of spectral evidence. The effect of saponification time on the amount of extracted carotenes is investigated. Quantitation results in a combined alpha- and beta-carotene concentration of at least 506 ppm. The detection limit for beta-carotene is 31 ng.


Subject(s)
Carotenoids/analysis , Plant Oils/analysis , Chromatography, High Pressure Liquid , Electrochemistry , Palm Oil , Stereoisomerism
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