20 results on '"Loo PS"'
Search Results
2. Neutralizing Autoantibodies against Interleukin-10 in Inflammatory Bowel Disease.
- Author
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Griffin H, Ceron-Gutierrez L, Gharahdaghi N, Ebrahimi S, Davies S, Loo PS, Szabo A, Williams E, Mukhopadhyay A, McLoughlin L, Irwin S, Travis S, Klenerman P, Bunn S, Cant AJ, Hambleton S, Uhlig HH, and Doffinger R
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- Female, Humans, Infant, Male, B-Lymphocytes drug effects, B-Lymphocytes immunology, Immunoglobulins, Intravenous administration & dosage, Glucocorticoids administration & dosage, Drug Therapy, Combination methods, Infliximab administration & dosage, Child, Preschool, Severity of Illness Index, Treatment Outcome, Antibodies, Neutralizing immunology, Antibodies, Neutralizing blood, Autoantibodies immunology, Autoantibodies blood, Inflammatory Bowel Diseases blood, Inflammatory Bowel Diseases diagnosis, Inflammatory Bowel Diseases drug therapy, Inflammatory Bowel Diseases immunology, Interleukin-10 immunology
- Abstract
We discovered high-titer neutralizing autoantibodies against interleukin-10 in a child with infantile-onset inflammatory bowel disease (IBD), a phenocopy of inborn errors of interleukin-10 signaling. After B-cell-depletion therapy and an associated decrease in the anti-interleukin-10 titer, conventional IBD therapy could be withdrawn. A second child with neutralizing anti-interleukin-10 autoantibodies had a milder course of IBD and has been treated without B-cell depletion. We conclude that neutralizing anti-interleukin-10 autoantibodies may be a causative or modifying factor in IBD, with potential implications for therapy. (Funded by the National Institute for Health and Care Research and others.)., (Copyright © 2024 Massachusetts Medical Society.)
- Published
- 2024
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3. Expanding the PRAAS spectrum: De novo mutations of immunoproteasome subunit β-type 10 in six infants with SCID-Omenn syndrome.
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van der Made CI, Kersten S, Chorin O, Engelhardt KR, Ramakrishnan G, Griffin H, Schim van der Loeff I, Venselaar H, Rothschild AR, Segev M, Schuurs-Hoeijmakers JHM, Mantere T, Essers R, Esteki MZ, Avital AL, Loo PS, Simons A, Pfundt R, Warris A, Seyger MM, van de Veerdonk FL, Netea MG, Slatter MA, Flood T, Gennery AR, Simon AJ, Lev A, Frizinsky S, Barel O, van der Burg M, Somech R, Hambleton S, Henriet SSV, and Hoischen A
- Subjects
- Infant, Humans, Proteasome Endopeptidase Complex genetics, Proteasome Endopeptidase Complex metabolism, Mutation genetics, T-Lymphocytes metabolism, Mutation, Missense genetics, Severe Combined Immunodeficiency genetics, Severe Combined Immunodeficiency metabolism
- Abstract
Mutations in proteasome β-subunits or their chaperone and regulatory proteins are associated with proteasome-associated autoinflammatory disorders (PRAAS). We studied six unrelated infants with three de novo heterozygous missense variants in PSMB10, encoding the proteasome β2i-subunit. Individuals presented with T-B-NK± severe combined immunodeficiency (SCID) and clinical features suggestive of Omenn syndrome, including diarrhea, alopecia, and desquamating erythematous rash. Remaining T cells had limited T cell receptor repertoires, a skewed memory phenotype, and an elevated CD4/CD8 ratio. Bone marrow examination indicated severely impaired B cell maturation with limited V(D)J recombination. All infants received an allogeneic stem cell transplant and exhibited a variety of severe inflammatory complications thereafter, with 2 peri-transplant and 2 delayed deaths. The single long-term transplant survivor showed evidence for genetic rescue through revertant mosaicism overlapping the affected PSMB10 locus. The identified variants (c.166G>C [p.Asp56His] and c.601G>A/c.601G>C [p.Gly201Arg]) were predicted in silico to profoundly disrupt 20S immunoproteasome structure through impaired β-ring/β-ring interaction. Our identification of PSMB10 mutations as a cause of SCID-Omenn syndrome reinforces the connection between PRAAS-related diseases and SCID., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024. Published by Elsevier Inc.)
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- 2024
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4. Understanding the role of the Tanzania national health insurance fund in improving service coverage and quality of care.
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Osei Afriyie D, Loo PS, Kuwawenaruwa A, Kassimu T, Fink G, Tediosi F, and Mtenga S
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- Humans, Tanzania, Insurance, Health, Quality of Health Care, National Health Programs, Financial Management
- Abstract
Health insurance is one of the main financing mechanisms currently being used in low and middle-income countries to improve access to quality services. Tanzania has been running its National Health Insurance Fund (NHIF) since 2001 and has recently undergone significant reforms. However, there is limited attention to the causal mechanisms through which NHIF improves service coverage and quality of care. This paper aims to use a system dynamics (qualitative) approach to understand NHIF causal pathways and feedback loops for improving service coverage and quality of care at the primary healthcare level in Tanzania. We used qualitative interviews with 32 stakeholders from national, regional, district, and health facility levels conducted between May to July 2021. Based on the main findings and themes generated from the interviews, causal mechanisms, and feedback loops were created. The majority of feedback loops in the CLDs were reinforcing cycles for improving service coverage among beneficiaries and the quality of care by providers, with different external factors affecting these two actions. Our main feedback loop shows that the NHIF plays a crucial role in providing additional financial resources to facilities to purchase essential medical commodities to deliver care. However, this cycle is often interrupted by reimbursement delays. Additionally, beneficiaries' perception that lower-level facilities have poorer quality of care has reinforced care seeking at higher-levels. This has decreased lower level facilities' ability to benefit from the insurance and improve their capacity to deliver quality care. Another key finding was that the NHIF funding has resulted in better services for insured populations compared to the uninsured. To increase quality of care, the NHIF may benefit from improving its reimbursement administrative processes, increasing the capacity of lower levels of care to benefit from the insurance and appropriately incentivizing providers for continuity of care., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)
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- 2024
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5. A novel colorectal cancer test combining microsatellite instability and BRAF/RAS analysis: Clinical validation and impact on Lynch syndrome screening.
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Gallon R, Herrero-Belmonte P, Phelps R, Hayes C, Sollars E, Egan D, Spiewak H, Nalty S, Mills S, Loo PS, Borthwick GM, Santibanez-Koref M, Burn J, McAnulty C, and Jackson MS
- Abstract
Background: Lynch syndrome (LS) is under-diagnosed. UK National Institute for Health and Care Excellence guidelines recommend multistep molecular testing of all colorectal cancers (CRCs) to screen for LS. However, the complexity of the pathway has resulted in limited improvement in diagnosis., Methods: One-step multiplex PCR was used to generate sequencing-ready amplicons from 14 microsatellite instability (MSI) markers and 22 BRAF , KRAS , and NRAS mutation hotspots. MSI and BRAF/RAS variants were detected using amplicon-sequencing and automated analysis. The assay was clinically validated and deployed into service in northern England, followed by regional and local audits to assess its impact., Results: MSI analysis achieved 99.1% sensitivity and 99.2% specificity and was reproducible (r = 0.995). Mutation hotspot analysis had 100% sensitivity, 99.9% specificity, and was reproducible (r = 0.998). Assay-use in service in 2022-2023 increased CRC testing (97.2% (2466/2536) versus 28.6% (601/2104)), halved turnaround times, and identified more CRC patients at-risk of LS (5.5% (139/2536) versus 2.9% (61/2104)) compared to 2019-2020 when a multi-test pathway was used., Conclusion: A novel amplicon-sequencing assay of CRCs, including all biomarkers for LS screening and anti-EGFR therapy, achieved >95% testing rate. Adoption of this low cost, scalable, and fully automatable test will complement on-going, national initiatives to improve LS screening., Competing Interests: Competing interestsR. Gallon, J. Burn, M. S. Jackson, and M. Santibanez-Koref are named inventors on patents covering the microsatellite instability markers analysed: WO/2018/037231 (published March 1, 2018), WO/2021/019197 (published February 4, 2021), and GB2114136.1 (filed October 1, 2021). The other authors declare no conflicts of interest., (© The Author(s) 2024.)
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- 2024
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6. Unveiling Maternal Health Insights During the COVID-19 Pandemic in Pakistan: Using Causal Loop Diagrams to Illuminate and Prevent Unintended Policy Effects.
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Zafar S, Loo PS, Avais AR, Afghan S, de Savigny D, Muñoz DC, and Fruchtman CS
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- Female, Humans, Maternal Health, Pakistan epidemiology, Pandemics prevention & control, Policy, COVID-19 epidemiology, COVID-19 prevention & control
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- 2023
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7. Primary mediastinal seminoma with florid follicular lymphoid hyperplasia: a case report and review of the literature.
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Holmes C, Loo PS, and Barnard S
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- Adult, Biomarkers, Tumor analysis, Humans, Hyperplasia, Male, Mediastinal Neoplasms chemistry, Mediastinal Neoplasms diagnostic imaging, Mediastinal Neoplasms surgery, Middle Aged, Seminoma chemistry, Seminoma diagnostic imaging, Seminoma surgery, Treatment Outcome, Young Adult, Mediastinal Neoplasms pathology, Seminoma pathology
- Abstract
Background: First described in 1955 Primary mediastinal seminomas are rare. Only 1-4% of mediastinal tumours are germ cell tumors; majority of which are teratomas. They typically present in men aged between 20 and 40 years. Very few cases are reported in the literature. Florid follicular lymphoid hyperplasia can obscure the malignant cells and is a rarer finding still. We present a rare case of a 48 year old man with a primary mediastinal seminoma with florid follicular lymphoid hyperplasia; found following excision of a clinically presumed thymoma., Case Presentation: A 48 year old man was referred for excision of a thymic mass. The presumed diagnosis was a thymoma; following preoperative investigations. The mass was incidentally found on a radiological imaging. However, the patient did report mid-sternal discomfort on lying flat and breathlessness. The patient underwent a thymectomy via a partial median sternotomy with good recovery. Histological assessment was that the mass was in fact a primary mediastinal seminoma with florid follicular lymphoid hyperplasia. A primary testicular malignancy was excluded and the patient required no further oncological treatment., Conclusions: Only 11 cases have previously been reported of primary mediastinal seminoma with florid follicular lymphoid hyperplasia. Although rare, a primary mediastinal seminoma should be considered as a differential diagnosis for presentations with a thymic mass. Tumour markers can be helpful, however are only positive in third of cases. Ultrasound imaging of the gonads is essential to exclude a primary gonadal lesion. Pure seminomas are radiotherapy and chemotherapy sensitive however the mainstay treatment of primary mediastinal seminomas remains surgical excision. Radiotherapy is reserved postoperatively for incomplete surgical margins., (© 2021. The Author(s).)
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- 2021
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8. Inherited pulmonary cylindromas: extending the phenotype of CYLD mutation carriers.
- Author
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Brown SM, Arefi M, Stones R, Loo PS, Barnard S, Bloxham C, Stefanos N, Langtry JAA, Worthy S, Calonje E, Husain A, and Rajan N
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- Adult, Aged, Carrier State diagnostic imaging, DNA Mutational Analysis, Female, Germ-Line Mutation, Humans, Lung diagnostic imaging, Lung Neoplasms complications, Lung Neoplasms diagnostic imaging, Lung Neoplasms genetics, Male, Middle Aged, Neoplastic Syndromes, Hereditary diagnostic imaging, Neoplastic Syndromes, Hereditary genetics, Retrospective Studies, Skin Neoplasms diagnostic imaging, Skin Neoplasms genetics, Carrier State pathology, Deubiquitinating Enzyme CYLD genetics, Dyspnea etiology, Lung Neoplasms secondary, Neoplastic Syndromes, Hereditary pathology, Skin Neoplasms pathology
- Abstract
Background: Germline mutations in the tumour suppressor gene CYLD are recognized to be associated with the development of multiple cutaneous cylindromas. We encountered such a patient who presented with breathlessness because of multiple pulmonary cylindromas., Objectives: To search for clinical and radiological features of multiple pulmonary cylindromas in a cohort of 16 patients with CYLD mutations., Methods: A retrospective case-note review was carried out in a tertiary dermatogenetics clinic where CYLD mutation carriers are reviewed on an annual basis. In-depth investigation was carried out for patients with pulmonary tumours., Results: Four patients had radiological imaging of their lungs, of which two had multiple pulmonary cylindromas that were confirmed histologically. Serial computed tomography monitoring allowed for pre-emptive endobronchial laser ablation, preventing major airway obstruction and pulmonary collapse., Conclusions: Pulmonary cylindromas are an unrecognized, but infrequently symptomatic, aspect of the phenotype in these patients that can have implications for patient care. They should be considered in patients with a high tumour burden that present with respiratory symptoms, and where appropriate, monitored with serial imaging., (© 2018 The Authors. British Journal of Dermatology published by John Wiley & Sons Ltd on behalf of British Association of Dermatologists.)
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- 2018
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9. Serpin b3 is associated with poor survival after chemotherapy and is a potential novel predictive biomarker in advanced non-small-cell lung cancer.
- Author
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Urquhart G, Kerr KM, Nicolson M, Loo PS, Sharma R, Shrimali R, and Petty RD
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- Adenocarcinoma drug therapy, Adenocarcinoma metabolism, Adult, Aged, Biomarkers, Tumor metabolism, Carcinoma, Large Cell drug therapy, Carcinoma, Large Cell metabolism, Carcinoma, Non-Small-Cell Lung drug therapy, Carcinoma, Non-Small-Cell Lung metabolism, Carcinoma, Squamous Cell drug therapy, Carcinoma, Squamous Cell metabolism, Female, Follow-Up Studies, Humans, Immunoenzyme Techniques, Lung Neoplasms drug therapy, Lung Neoplasms metabolism, Male, Middle Aged, Neoplasm Staging, Prognosis, Prospective Studies, Survival Rate, Adenocarcinoma mortality, Antigens, Neoplasm metabolism, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Carcinoma, Large Cell mortality, Carcinoma, Non-Small-Cell Lung mortality, Carcinoma, Squamous Cell mortality, Lung Neoplasms mortality, Serpins metabolism
- Abstract
Introduction: In a previous biomarker discovery project using gene-expression profiling we identified Serpin B3 (SB3) as a predictor of resistance to platinum doublet chemotherapy (PtC) in non-small-cell lung cancer (NSCLC). This independent prospective study was designed to confirm the predictive utility of SB3., Methods: SB3 immunohistochemistry was scored by previously validated criteria (score 0 = negative, score 1 = 1%-10% tumor cells positive, score 2 = 11%-50% tumor cells positive, and score 3 = >50% tumor cell positive) in 197 patients with stage IV NSCLC treated with PtC. This provided 80% power to detect a median survival increase from 150 days in patients with an SB3 immunohistochemistry score of 2 or more to 300 days in those with an SB3 score of 0 or 1., Results: Thirty-six percent of NSCLCs stained positive for SB3. Median survival for SB3 negative/score 0 was 332 days, SB3 positive/score 1 was 268 days, and SB3 positive/score 2 or 3 was 120 days (p = 0.004). Cox proportional hazards analysis demonstrated that SB3 positivity is an independent predictor of survival (hazard ratio = 1.87; 95% confidence interval, 1.29-2.71; p = 0.001).The disease control rate in SB3 score 0, 1 = 65%, and score of 2 or more = 20 % (p = 0.002), with median survival 306 days (score 0, 1) versus 120 days (score ≥ 2, hazard ratio= 1.71; 95% confidence interval. 1.14-3.10; p = 0.002)., Conclusions: SB3-positive immunohistochemistry score of 2 or more (>10% tumor cells positive) identifies a subgroup of patients with stage IV NSCLC who have a poor survival (median 120 days) when treated with PtC, similar to that estimated for untreated or chemo-refractory stage IV NSCLC. Further prospective qualification using biospecimens from randomized studies is needed, but SB3 seems to be a useful biomarker that identifies a highly resistant subgroup in whom PtC should be avoided.
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- 2013
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10. Subtyping of undifferentiated non-small cell carcinomas in bronchial biopsy specimens.
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Loo PS, Thomas SC, Nicolson MC, Fyfe MN, and Kerr KM
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- Adenocarcinoma metabolism, Adenocarcinoma pathology, Biopsy, Fine-Needle, Bronchi pathology, Carcinoma, Large Cell metabolism, Carcinoma, Large Cell pathology, Carcinoma, Non-Small-Cell Lung metabolism, Carcinoma, Non-Small-Cell Lung pathology, Carcinoma, Squamous Cell metabolism, Carcinoma, Squamous Cell pathology, Cell Differentiation, Humans, Immunoenzyme Techniques, Keratin-5 metabolism, Keratin-6 metabolism, Lung Neoplasms metabolism, Lung Neoplasms pathology, Mucins metabolism, Neoplasm Staging, Nuclear Proteins metabolism, Prognosis, Prospective Studies, S100 Calcium Binding Protein A7, S100 Proteins metabolism, Sensitivity and Specificity, Survival Rate, Thyroid Nuclear Factor 1, Trans-Activators metabolism, Transcription Factors metabolism, Tumor Suppressor Proteins metabolism, Adenocarcinoma classification, Biomarkers, Tumor metabolism, Bronchi metabolism, Carcinoma, Large Cell classification, Carcinoma, Non-Small-Cell Lung classification, Carcinoma, Squamous Cell classification, Lung Neoplasms classification
- Abstract
Introduction: The emergence of treatments for non-small cell lung carcinoma (NSCLC) with differential efficacy and toxicity between subtypes has highlighted the importance of specific pathologic NSCLC subtyping. Most NSCLCs are inoperable, and pathologic diagnosis is made only on small tissue samples that are prone to diagnostic inaccuracy. In a substantial proportion of cases, standard morphology cannot specifically subtype the tumor, necessitating a diagnosis of NSCLC-not otherwise specified (NOS). Histochemical staining for mucin and immunohistochemical (IHC) identification of NSCLC subtype-associated markers could help predict the final subtype of resected NSCLCs diagnosed as NSCLC-NOS on preoperative bronchial biopsy samples., Methods: Paraffin sections of 44 bronchial biopsy samples diagnosed as NSCLC-NOS were stained for mucin (Alcian blue/periodic acid Schiff) and thyroid transcription factor 1 by IHC-(markers of adenocarcinoma), and for S100A7, cytokeratin 5/6, high molecular weight cytokeratins, and p63 proteins-markers of squamous cell carcinoma. A predictive staining panel was derived from statistical analysis after comparing staining profiles with the final postsurgical NSCLC subtype. This panel was prospectively applied to 82 small biopsy samples containing NSCLC., Results: True NSCLC subtype of undifferentiated NSCLC samples was best predicted using Alcian blue/periodic acid Schiff plus p63 and thyroid transcription factor 1 IHC, allowing specific subtyping in 73% of NSCLC-NOS cases with 86% accuracy. When applied prospectively, this staining panel showed 100% concordance with specific NSCLC morphologic subtyping in small biopsies., Conclusion: This approach can facilitate treatment selection by accurately predicting the subtype in undifferentiated NSCLC biopsies, reducing to 7% the proportion of cases without a definite or probable histologic subtype.
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- 2010
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11. Hydroxycarbamide-induced pneumonitis.
- Author
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Loo PS, Khan M, Currie GP, Husain E, and Kerr KM
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- Female, Follow-Up Studies, Humans, Middle Aged, Pneumonia diagnostic imaging, Radiography, Time Factors, Enzyme Inhibitors adverse effects, Hydroxyurea adverse effects, Pneumonia chemically induced, Ribonucleotide Reductases antagonists & inhibitors
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- 2009
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12. Anxiolytic properties of certain annelated [1,2,4]triazolo[1,5-c]pyrimidin-5(6H)-ones.
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Francis JE, Bennett DA, Hyun JL, Rovinski SL, Amrick CL, Loo PS, Murphy D, Neale RF, and Wilson DE
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- Aggression drug effects, Animals, Conditioning, Operant drug effects, Pyrimidinones metabolism, Radioligand Assay, Rats, Structure-Activity Relationship, Triazoles metabolism, Anti-Anxiety Agents metabolism, Pyrimidinones pharmacology, Triazoles pharmacology
- Abstract
Modification of the benzodiazepine (BZ) receptor binding template 2-aryl[1,2,4]triazolo[1,5-c]quinazolin-5(6H)-one by replacement of the annelated benzene ring with various alicyclic and heterocyclic moieties led to novel structures with potent BZ receptor binding affinity. High affinity was found in some cycloalkyl-annelated [1,2,4]triazolo[1,5-c]pyrimidin-5(6H)-ones and in some 7,8,9,10-tetrahydropyrido[3,4-e][1,2,4]triazolo[1,5-c]pyrimidin- 5(6H)-ones, in which the degree of activity was strongly dependent on the N-substituent in the 9-position. Nine compounds with BZ receptor IC50 binding affinity values equal or superior to diazepam were evaluated in secondary screening. One of these, 9-benzyl-2-phenyl-7,8,9,10-tetrahydropyrido[3,4-e] [1,2,4]triazolo[1,5-c]pyrimidin-5(6H)-one, showed good activity in rats as a potential anxiolytic agent without sedative liability. However, it increased the rotorod deficit produced by ethanol at anxiolytic doses, an indication of alcohol interaction. Thus, none of the compounds showed an advantage over CGS 9896 (Yokoyama et al. J. Med. Chem. 1982, 25, 337-339), which is free of sedative and alcohol interaction potential as measured by the test procedures described.
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- 1991
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13. Synthesis and benzodiazepine binding activity of a series of novel [1,2,4]triazolo[1,5-c]quinazolin-5(6H)-ones.
- Author
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Francis JE, Cash WD, Barbaz BS, Bernard PS, Lovell RA, Mazzenga GC, Friedmann RC, Hyun JL, Braunwalder AF, and Loo PS
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- Animals, Binding, Competitive, Diazepam metabolism, Flunitrazepam metabolism, Indicators and Reagents, Molecular Structure, Quinazolines chemistry, Quinazolines pharmacology, Rats, Receptors, GABA-A drug effects, Structure-Activity Relationship, Triazoles chemistry, Triazoles pharmacology, Brain metabolism, Quinazolines chemical synthesis, Receptors, GABA-A metabolism, Triazoles chemical synthesis
- Abstract
Investigation of tricyclic heterocycles related to the 2-arylpyrazolo[4,3-c]quinolin-3(5H)-ones, structures with high affinity for the benzodiazepine (BZ) receptor, led to the synthesis of 2-phenyl-[1,2,4]triazolo[1,5-c]quinazolin-5(6H)-one, a compound with 4 nM binding affinity to the BZ receptor. Analogues were prepared to assess the importance of the 2-substituent and ring substitution in modifying activity. Several novel synthetic routes were designed to prepare the target compounds, including a two-step synthesis beginning with an anthranilonitrile and a hydrazide. Of the 34 compounds screened in this series, three compounds were found to be potent BZ antagonists in rat models. The leading compound, 9-chloro-2-(2-fluorophenyl) [1,2,4]triazolo[1,5- c]quinazolin-5(6H)-one (CGS 16228), showed activity comparable to that of CGS 8216 from the pyrazolo[4,3-c]quinoline series.
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- 1991
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14. CGS 20625, a novel pyrazolopyridine anxiolytic.
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Williams M, Bennett DA, Loo PS, Braunwalder AF, Amrick CL, Wilson DE, Thompson TN, Schmutz M, Yokoyoma N, and Wasley JW
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- Animals, Diazepam pharmacology, Male, Motor Activity drug effects, Rats, Rats, Inbred Strains, Receptors, Cholecystokinin drug effects, Receptors, GABA-A drug effects, Anti-Anxiety Agents pharmacology, Anticonvulsants pharmacology, Pyrazoles pharmacology
- Abstract
CGS 20625 (2-(4-methoxyphenyl)2,3,5,6,7,8,9,10-octa hydrocyclohepta[b]pyrazolo-[3,4-d]pyridin-3-one) is a potent and selective ligand for the central benzodiazepine receptor (IC50 = 1.3 nM), with little or no affinity to several other neurotransmitter receptor binding sites in vitro. CGS 20625 had a gamma-aminobutyric acid ratio of 0.9 and increased t-[35S]butylbicyclophosphorothionate binding by 20% in vitro, a profile indicative of a partial agonist or mixed agonist/antagonist. In vivo, CGS 20625 blocked a pentylenetetrazol discriminative cue with an ED50 = 1.7 mg/kg p.o. The compound selectively increased conflict responding in the Cook-Davidson paradigm with a minimal effective dose of 0.3 mg/kg p.o., as compared with 3.0 mg/kg p.o. for diazepam. At doses as high as 100 mg/kg p.o., CGS 20625 had no effect on variable interval responding, suggesting minimal sedation. Unlike diazepam, CGS 20625 had no effect on rotorod performance at doses up to 100 mg/kg p.o. indicating no overt muscle relaxation, and did not potentiate the action of ethanol in this behavioral paradigm. Also, CGS 20625 had no marked effect on locomotor behavior, did not potentiate hexobarbital sleep time and had no sedative activity at doses up to 300 mg/kg p.o. CGS 20625 was efficacious in preventing pentylenetetrazol-induced seizures (ED50 = 0.7 mg/kg p.o.), had less efficacy with no clear dose-response relationship against picrotoxin-induced seizures and had no effect on either strychnine or electroshock-induced convulsions at doses up to 300 mg/kg p.o.(ABSTRACT TRUNCATED AT 250 WORDS)
- Published
- 1989
15. Treatment of uncomplicated gonorrhoea in women with a combination of rifampicin and erythromycin.
- Author
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Boakes AJ, Loo PS, Ridgway GL, Tovey S, and Oriel JD
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- Adolescent, Adult, Chlamydia Infections drug therapy, Chlamydia trachomatis, Drug Therapy, Combination, Erythromycin administration & dosage, Female, Humans, Middle Aged, Rifampin administration & dosage, Erythromycin therapeutic use, Gonorrhea drug therapy, Rifampin therapeutic use
- Abstract
One hundred women with uncomplicated gonorrhoea (in five cases due to penicillinase producing strains of Neisseria gonorrhoeae (PPNG)) were treated with a single oral dose of rifampicin 900 mg and erythromycin stearate 1 g. N gonorrhoeae was reisolated from the oropharynx of one patient, who was infected with a PPNG strain, but was eradicated from the genital tract in 100% of cases. The combination eradicated Chlamydia trachomatis from only 10 (28%) of the 36 patients infected. Side effects were predominantly mild and consisted of transient nausea. The treatment merits evaluation in areas with a high incidence of PPNG strains.
- Published
- 1984
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16. Tricyclic antidepressants and dextromethorphan bind with higher affinity to the phencyclidine receptor in the absence of magnesium and L-glutamate.
- Author
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Sills MA and Loo PS
- Subjects
- Animals, Antidepressive Agents, Tricyclic metabolism, Dextromethorphan metabolism, Glutamic Acid, In Vitro Techniques, Male, Phencyclidine analogs & derivatives, Phencyclidine metabolism, Rats, Rats, Inbred Strains, Receptors, N-Methyl-D-Aspartate, Receptors, Neurotransmitter drug effects, Receptors, Phencyclidine, Antidepressive Agents, Tricyclic pharmacology, Dextromethorphan pharmacology, Glutamates pharmacology, Levorphanol analogs & derivatives, Magnesium pharmacology, Receptors, Neurotransmitter metabolism
- Abstract
Recent studies from our laboratory have provided evidence that multiple states of the phencyclidine (PCP) receptor exist. In addition, several compounds such as PCP and the novel anticonvulsant MK-801 were found to inhibit binding more potently in the presence of Mg2+ and L-glutamate (L-GLU) than when these agents were excluded from the binding assay. In the present study, a number of pharmacological compounds that have been suggested to interact within the N-methyl-D-aspartate (NMDA) receptor complex, including tricyclic antidepressants (TCAs), were examined for their ability to inhibit the binding of [3H]1-[1-(2-thienyl)cyclohexyl]piperidine [( 3H]TCP) in the absence or presence of Mg2+ and L-GLU. The TCAs imipramine, amitriptyline, and opipramol produced shallow inhibition curves in the absence of Mg2+ and L-GLU. Computer analysis of the binding data indicated that a two-component binding model described the data significantly better than a one-component model. In the presence of Mg2+ and L-GLU, the inhibition curves became steeper and were shifted to the right, and computer analysis of the binding data indicated that a one-component model adequately described the binding data. A series of other centrally active compounds, including several antipsychotics and antihistamines, the antiparkinsonian anticholinergic trihexyphenidyl and the antitussive dextromethorphan, were also found to be affected similarly by the inclusion of Mg2+ and L-GLU in the binding assay. Dextrorphan, in contrast to dextromethorphan, inhibited [3H]TCP binding more potently in the presence of Mg2+ and L-GLU. The present results suggest that the compounds that inhibit binding more potently in the absence of Mg2+ and L-GLU are interacting with the PCP receptor in a different manner from that of PCP and MK-801, because these open-channel blockers inhibit [3H]TCP binding more potently in the presence of Mg2+ and L-GLU. The data support previous findings that TCAs interact with the NMDA receptor complex and suggest that the compounds trihexyphenidyl and dextromethorphan, which have been shown to block NMDA-mediated neurotoxicity, may produce their effects through an interaction with the PCP receptor, albeit by a different mechanism from that of open-channel blockers.
- Published
- 1989
17. Interaction of L-glutamate and magnesium with phencyclidine recognition sites in rat brain: evidence for multiple affinity states of the phencyclidine/N-methyl-D-aspartate receptor complex.
- Author
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Loo PS, Braunwalder AF, Lehmann J, Williams M, and Sills MA
- Subjects
- Animals, Glutamic Acid, In Vitro Techniques, Kinetics, Male, Phenazocine analogs & derivatives, Phenazocine metabolism, Phencyclidine analogs & derivatives, Phencyclidine metabolism, Rats, Rats, Inbred Strains, Receptors, N-Methyl-D-Aspartate, Receptors, Neurotransmitter drug effects, Receptors, Phencyclidine, Brain metabolism, Glutamates pharmacology, Magnesium pharmacology, Receptors, Neurotransmitter metabolism
- Abstract
Biochemical and electrophysiological studies have provided evidence that a complex comprising the N-methyl-D-aspartate (NMDA)-type excitatory amino acid (EAA) receptor and the phencyclidine (PCP) recognition site exists in mammalian brain. This complex, which has been compared to that established for the inhibitory amino acid, gamma-aminobutyric acid, and the benzodiazepine anxiolytic, diazepam, is sensitive to the effects of the divalent cation Mg2+, which has suggested the presence of a third, ion channel component. Using a radioreceptor assay for the PCP receptor, L-glutamate (L-Glu) produced a concentration-dependent increase in the binding of [3H]thienyl cyclohexylpiperazine ([3H]TCP) in well washed membranes from rat forebrain. The EAA produced a maximal increase in specific binding of 400%, with an EC50 value of 340 nM. The ability of L-Glu to enhance [3H]TCP binding was 10-fold more potent in the presence of 30 microM Mg2+, which inhibits NMDA-evoked responses in intact tissue preparations and produces a 50% increase in [3H]TCP binding on its own. Analysis of saturation curves indicated that the effect of both L-Glu and Mg2+ could be attributed to an increase in receptor affinity as well as increases in the proportion of a high affinity state of the PCP-binding site. Assessment of the effect of a number of EAAs on basal [3H]TCP binding (well washed membranes in the absence of either L-Glu or Mg2+) showed that the EAA recognition site involved in the effects of L-Glu was the NMDA subtype. Further studies examined a series of compounds thought to interact with either the NMDA or PCP components of the receptor complex under four binding conditions: basal, +Mg2+; +L-Glu; and +Mg2+/L-Glu. These results showed that dissociative anesthetics, such as dexoxadrol and PCP, as well as the novel anticonvulsant MK-801, selectively interact with the high affinity state of the PCP receptor. NMDA antagonists, such as CPP, were also found to inhibit binding to the high affinity state of the PCP receptor, although not as potently as the dissociative anesthetics. Interestingly, the NMDA antagonists did not inhibit any of the binding to the low affinity state of the receptor. The sigma ligands (+/-)-SKF 10,047 and haloperidol recognized two components of [3H]TCP binding only in the presence of L-Glu. The results of the present study are consistent with the finding that agonists of the NMDA receptor induce a high affinity state of the PCP receptor.
- Published
- 1987
18. Treatment of gonococcal infections in men with single dose thiamphenicol.
- Author
-
Loo PS, Felmingham D, Ridgway GL, and Oriel JD
- Subjects
- Drug Administration Schedule, Humans, Male, Gonorrhea drug therapy, Thiamphenicol therapeutic use
- Published
- 1983
- Full Text
- View/download PDF
19. Single dose ciprofloxacin for treating gonococcal infections in men.
- Author
-
Loo PS, Ridgway GL, and Oriel JD
- Subjects
- Anti-Infective Agents adverse effects, Anti-Infective Agents therapeutic use, Chlamydia Infections complications, Ciprofloxacin, Gonorrhea complications, Humans, Male, Pharyngitis drug therapy, Proctitis drug therapy, Quinolines adverse effects, Quinolines therapeutic use, Urethritis drug therapy, Anti-Infective Agents administration & dosage, Gonorrhea drug therapy, Quinolines administration & dosage
- Abstract
A single oral dose of ciprofloxacin 500 mg was used to treat five men with gonococcal urethritis and five men with gonococcal proctitis, and all were cured. In a subsequent study the dose of ciprofloxacin was reduced to 250 mg, and 54 men with 57 gonococcal infections (47 urethral, seven rectal, and three pharyngeal) were treated; of the isolates of Neisseria gonorrhoeae, four were penicillinase producing strains. All the patients were cured of gonococcal infection. Urethral specimens from nine of the men with gonococcal urethritis yielded Chlamydia trachomatis before treatment. These organisms were isolated again from all these patients seven days after treatment, and from a further seven men who had been chlamydia negative before treatment. It is concluded that a single oral dose of ciprofloxacin is an effective treatment for uncomplicated gonorrhoea, but is ineffective against C trachomatis. Of the 54 men given 250 mg ciprofloxacin, six (11%) showed minor abnormalities of liver function tests after treatment.
- Published
- 1985
- Full Text
- View/download PDF
20. The NMDA antagonists, CPP and CGS 19755, lack affinity for central benzodiazepine receptors.
- Author
-
Williams M, Loo PS, and Sills MA
- Subjects
- Animals, Aspartic Acid antagonists & inhibitors, Binding, Competitive drug effects, Brain drug effects, Brain metabolism, Flunitrazepam metabolism, In Vitro Techniques, N-Methylaspartate, Rats, Receptors, GABA-A drug effects, Anticonvulsants metabolism, Aspartic Acid analogs & derivatives, Pipecolic Acids, Piperazines metabolism, Piperidines metabolism, Receptors, GABA-A metabolism
- Abstract
CPP (3-(2-carboxypiperazin-4-yl-propyl-1-phosphonic acid), a rigid analog of AP7 (2-amino-7-phosphonoheptanoate), previously shown to be a selective antagonist of the NMDA (N-methyl-D-aspartate) receptor (IC50 = 209 nM) has been reported to be exceptionally active (IC50 = 430 pM) at benzodiazepine binding sites. Re-examination of CPP, and the rigid AP5 analog, CGS 19755 (cis-4-phosphonomethyl-2-piperidine carboxylic acid; 0.001-10,000 nM), showed that, as previously reported, neither compound affected the binding of [3H]flunitrazepam. These compounds are thus selective NMDA receptor antagonists.
- Published
- 1988
- Full Text
- View/download PDF
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