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Harvey RG, Olivrī A, Lima T, Olivry T. Effective treatment of canine chronic cutaneous lupus erythematosus variants with oclacitinib: Seven cases. Vet Dermatol 2023; 34:53-58. [PMID: 36229964 PMCID: PMC10092348 DOI: 10.1111/vde.13128] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 07/13/2022] [Accepted: 07/22/2022] [Indexed: 01/05/2023]
Abstract
BACKGROUND The treatment of canine chronic cutaneous lupus erythematosus (CCLE) variants generally requires immunosuppression, which often results in potentially severe adverse effects. Janus kinase inhibitors, like oclacitinib, might be a valuable treatment option due to their rapid inhibition of the action of interferons known to be relevant in the pathogenesis of CCLE. OBJECTIVES To report the efficacy and safety of oral oclacitinib for the treatment of canine CCLE variants. ANIMALS Seven dogs were diagnosed with CCLE based on clinical signs and compatible histopathological findings. MATERIALS AND METHODS Oclacitinib was administered at the induction dosage of 0.45 mg/kg twice daily to 1.8 mg/kg once daily. The response to treatment was graded as 'good' when there was ≥50% lesion reduction, or as 'complete remission' if all active lesions had resolved. Complete blood counts were performed at variable intervals. RESULTS A complete remission of all lesions was obtained in the dog with exfoliative cutaneous lupus erythematosus, both dogs with mucocutaneous lupus erythematosus and three of four dogs with facial discoid lupus erythematosus (FDLE); a good response was seen in the remaining dog with FDLE. The first visible improvement of signs was seen within 2-to-3 weeks, while the time to complete remission was around 2 months. Clinical adverse effects were not seen, and haematological parameters remained within the reference range. CONCLUSIONS AND CLINICAL RELEVANCE Oclacitinib may be considered an effective treatment option for different variants of canine CCLE.
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Affiliation(s)
| | - Alla Olivrī
- Veterinary Dermatology Riga, SIA Olivry Consulting, Riga, Latvia
| | - Tatiana Lima
- North Downs Specialist Referral, Bletchingley, UK
| | - Thierry Olivry
- Veterinary Dermatology Riga, SIA Olivry Consulting, Riga, Latvia
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Maltes S, Abecasis J, Pinto DG, Santos RR, Oliveira L, Mendes GS, Guerreiro S, Lima T, Freitas P, Ferreira A, Ramos S, Felix A, Cardim N, Gil VM, Mendes M. Histology-verified myocardial fibrosis and quantification in severe AS patients: correlation with non-invasive LV myocardial tissue assessment. Eur Heart J 2022. [DOI: 10.1093/eurheartj/ehac544.2996] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Myocardial fibrosis (MF) is a common finding and a potential adverse prognostic marker in several cardiac diseases, including in severe aortic stenosis (AS). While histological analysis obtained through endomyocardial biopsy remains the gold-standard for MF assessment, non-invasive cardiac imaging may offer surrogate biomarkers for fibrosis. We tried to assess the correlation between MF quantification at histopathology and cardiac magnetic resonance (CMR)-derived tissue characterization data in patients with severe AS.
Methodology
Single-center prospective cohort enrolling 71 patients with severe symptomatic high-gradient AS undergoing surgical aortic valve replacement (SAVR) (mean age 71±9 years; 49% male, mean valvular transaortic gradient 60±20 mmHg; mean left ventricle [LV] ejection fraction 58±9%). Those with past history of myocardial infarction or cardiomyopathy were excluded. All patients underwent pre-operative CMR study with LV tissue characterization and quantification. Normal T1 mapping value was defined as >1021ms as per center protocol. Myocardial tissue was obtained during SAVR either through myocardial biopsy at basal LV septum or harvested from surgical myectomy specimens. Masson's trichrome stain was used for collagen/fibrosis assessment. Automatic quantification was obtained at QuPathTM digital pathology software after applying a dedicated artificial intelligence algorithm on ultra-high-resolution digital slide scanning images.
Results
Histology-confirmed MF was observed in all patients (median percentage of fibrotic myocardial tissue 15% [IQR 9–22%]). Median global T1 mapping and extracellular volume (ECV) percentage was 1048ms (IQR 1027–1078) and 24% (IQR 20–30%), respectively. Late gadolinium enhancement (LGE) with a non-ischemic pattern was present in 42 patients (59%) with a median LGE mass of 5.8g [IQR 1.0–10.2]; median percentage of 3.7% [IQR 0.6–10.4]. While neither T1 mapping (global or basal LV septum), ECV nor LGE had any significant correlation with histology-confirmed MF (Figure 1) the vast majority had significantly elevated global and basal LV septum T1 mapping – 81% and 92%, respectively.
Conclusion
In this single-center prospective study, microscopic MF was present in all patients with severe symptomatic high-gradient AS, was accompanied by elevated T1 mapping values but no correlation was found between myocardial fibrosis at histopathology analysis and CMR-derived LV tissue characterization parameters. This may not only stem from sampling (single point biopsy vs. whole myocardial tissue assessment) but also from distinct evaluation of different types of fibrosis by different methods.
Funding Acknowledgement
Type of funding sources: None.
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Affiliation(s)
- S Maltes
- Hospital Santa Cruz , Lisbon , Portugal
| | | | - D G Pinto
- Hospital Santa Cruz , Lisbon , Portugal
| | | | | | | | | | - T Lima
- Hospital Santa Cruz , Lisbon , Portugal
| | - P Freitas
- Hospital Santa Cruz , Lisbon , Portugal
| | | | - S Ramos
- Hospital Santa Cruz , Lisbon , Portugal
| | - A Felix
- Portuguese Institute of Oncology Lisbon , Lisbon , Portugal
| | - N Cardim
- Hospital da Luz, SA , Lisbon , Portugal
| | - V M Gil
- Hospital da Luz, SA , Lisbon , Portugal
| | - M Mendes
- Hospital Santa Cruz , Lisbon , Portugal
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Maltes S, Abecasis J, Santos RR, Oliveira L, Mendes GS, Guerreiro S, Lima T, Freitas P, Ferreira A, Cardim N, Gil VM, Mendes M. Late gadolinium enhancement patterns in severe symptomatic high-gradient aortic stenosis. Eur Heart J 2022. [DOI: 10.1093/eurheartj/ehac544.233] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Left ventricular (LV) remodeling in patients with severe aortic valve stenosis (AS) is a complex process that goes beyond hypertrophic response and may involve reparative/replacement fibrosis. Currently, cardiac magnetic resonance (CMR) is the gold-standard imaging technique for detecting focal myocardial fibrosis through late gadolinium enhancement (LGE). However, myocardial fibrosis prevalence and distribution is quite variable among series. Our goal was to assess LGE prevalence and distribution pattern in severe symptomatic high-gradient AS.
Methodology
Single-center prospective cohort of 132 patients with severe symptomatic high-gradient AS (mean age 73±11 years; 48% male, mean valvular transaortic gradient 60±20 mmHg; mean aortic valve area 0.7±0.2 cm2/m2; mean LV ejection fraction by 2D echocardiogram 58±9%), all with normal flow (except one) undergoing surgical aortic valve replacement. Those with previous history of acute myocardial infarction, ischemic cardiomyopathy or other cardiomyopathy were excluded. All patients performed 1.5T CMR assessment with LV myocardium tissue characterization prior to surgery. Segmental LGE presence was assessed by two independent operators and classified according to the AHA 16 segment model, using 5-standard deviations from remote myocardium as the signal intensity cut-off for LGE identification and quantification.
Results
Overall, 96 patients (74%) had non-ischemic LGE (median LGE mass 3.2 g [IQR 0.2–8.3] g; median percentage of LGE myocardial mass 2.5% [IQR 0.1–6.1]%); 22 patients [17%] with exclusively junctional LGE); in one patient an incidental ischemic scar (subendocardial distribution) was identified. No cases of subepicardial distribution were found. Intramyocardial LGE was most frequently observed in basal and mid-anterior and inferior interventricular septum – see Figure 1. In these segments, LGE was most often junctional at right-ventricular insertion points (54%), followed by mid-wall LGE (32%) or both sites involvement (14%).
Conclusion
LGE is frequent in symptomatic high-gradient AS patients with preserved left ventricular ejection fraction, most often presenting as junctional enhancement in basal/mid-anterior and inferior interventricular septum. Future studies may address whether distinct LGE patterns may impact patient prognosis.
Funding Acknowledgement
Type of funding sources: None.
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Affiliation(s)
- S Maltes
- Hospital Santa Cruz , Lisbon , Portugal
| | | | | | | | | | | | - T Lima
- Hospital Santa Cruz , Lisbon , Portugal
| | - P Freitas
- Hospital Santa Cruz , Lisbon , Portugal
| | | | - N Cardim
- Hospital da Luz, SA , Lisbon , Portugal
| | - V M Gil
- Hospital da Luz, SA , Lisbon , Portugal
| | - M Mendes
- Hospital Santa Cruz , Lisbon , Portugal
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Sena G, Lima T, Melo T, Arruda S, Sales M, Mello M, Lima J. Factors Associated with Mortality in Older Cancer Patients with Sars from Covid-19: Explainable-AI Analysis. J Geriatr Oncol 2022. [PMCID: PMC9595426 DOI: 10.1016/s1879-4068(22)00428-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Psaltikidis EM, Lima T, Fagnani R, Cardoso L, Bachur L, Höfling CC, Mendes E, Oliveira F, Resende M, Velasco N, Moretti M. Outbreak of Surgical Site Infections by Serratia marcescens Related to Degermation Brush. Int J Infect Dis 2022. [DOI: 10.1016/j.ijid.2021.12.264] [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: 11/24/2022] Open
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Viry A, Aberle C, Lima T, Treier R, Schindera S, Verdun F, Racine D. Assessment of task-based image quality for abdominal CT protocols linked with national diagnostic reference levels. Phys Med 2021. [DOI: 10.1016/s1120-1797(22)00069-2] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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7
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Sa Mendes G, Abecasis J, Maltez S, Guerreiro S, Freitas P, Horta E, Lima T, Ribeiras R, Andrade M, Cardim N, Gil V. Left ventricular myocardial work in patients with high gradient severe symptomatic aortic stenosis. Eur Heart J 2021. [DOI: 10.1093/eurheartj/ehab724.1553] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Background
Left ventricular myocardial work (LVMW) is a novel method to evaluated left ventricular (LV) function using pressure-strain loops. It might correct global longitudinal strain (GLS) for afterload, being eventually useful to assess whether GLS reduction is due to reduced contractility (reflected as reduced myocardial work) or increased afterload (reflected as increased myocardial work).
Aim
To describe indices of LVMW in a group of patients with severe symptomatic aortic stenosis (AS).
Methods
We prospectively studied 104 consecutive patients (age: 71 years [IQR 66.5–75.5] years, 51% men) with severe symptomatic high gradient AS: mean transaortic pressure gradient: 56.5mmHg [IQR 46.8–67.8]; aortic valve area: 0.73cm2 [IQR 0.61–0.88]; indexed stroke volume: 47.7±1.3 mL/m2 (11 patients with low-flow AS), preserved LV ejection fraction (EV) (LVEF: 56.0% [51.0–61.3]; GLS: −14.5% [IQR −16.1 to −10.6]), with no previous coronary artery disease and no history of cardiomyopathy. Beyond complete transthoracic echocardiography, all patients underwent cardiac magnetic resonance for LV myocardium tissue characterization. As proposed for AS, LV systolic pressure was corrected adding the mean transaortic pressure gradient to non-invasive systolic blood pressure cuff measurement in the echocardiographic algorithm. Four LVMW indices were collected in 83 patients (patients excluded for atrial fibrillation, left bundle branch block or absence of non-invasive blood pressure registration) and correlated to LV function indexes, LV hypertrophy and remodeling, myocardial tissue characterization, BNP and troponin levels (Pearson or Spearman correlation). These same indexes were compared in patients with LV ejection fraction (EF) below and above 50%, normal and reduced flow and presence of replacement fibrosis.
Results
Global constructive work (GCW) (2658.6±76.4mmHg%), global myocardial work (GMW) (2218.7±74.9mmHg%) and global wasted work (GWE) (262.0mmHg% [198.8–339.5]) were high above normal with concomitant lower work efficiency (WE) (88.0% [83.2–91.8]. Weak correlations were found between LVMW indexes and parameters describing aortic valve severity, flow and LV function (table). Except for significant differences of LVMI in patients with reduced LV ejection fraction (GCW 2770.3±687.4 vs 2056.0±380.7mmHg%, p=0,014 and GMW 2362.5±657.9 vs 1621.3±319.9, p=0,021 in patients with LV EF>50% vs. LV EF<50%, respectively) work indexes were neither significantly different in low-flow patients nor in those with myocardial late gadolinium enhancement.
Conclusions
Global constructive and myocardial work are increased in these patients with severe aortic stenosis. This might reflect an increased afterload predominance rather than a LV functional impairment, particularly relevant in this group of patients with exclusive high gradient disease and preserved LVEF.
Funding Acknowledgement
Type of funding sources: None. Correlations between LVMI – LV function
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Affiliation(s)
| | - J Abecasis
- Hospital de Santa Cruz, Carnaxide, Portugal
| | - S Maltez
- Hospital de Santa Cruz, Carnaxide, Portugal
| | | | - P Freitas
- Hospital de Santa Cruz, Carnaxide, Portugal
| | - E Horta
- Hospital de Santa Cruz, Carnaxide, Portugal
| | - T Lima
- Hospital de Santa Cruz, Carnaxide, Portugal
| | - R Ribeiras
- Hospital de Santa Cruz, Carnaxide, Portugal
| | - M Andrade
- Hospital de Santa Cruz, Carnaxide, Portugal
| | - N Cardim
- Hospital da Luz, SA, Lisbon, Portugal
| | - V Gil
- Hospital dos Lusiadas, Lisbon, Portugal
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Ory J, Tradewell M, Lima T, Blankstein U, Madhusoodanan V, Moryousef J, Lau S, Jarvi K, Ramasamy R. P–016 Using artificial intelligence to predict semen upgrading after microsurgical varicocele repair. Hum Reprod 2021. [DOI: 10.1093/humrep/deab130.015] [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] Open
Abstract
Abstract
Study question
Can we use artificial intelligence models to predict semen upgrading after microsurgical varicocele repair?
Summary answer
A machine learning model performed well in predicting clinically meaningful post-varicocelectomy semen upgrade using pre-operative hormonal, clinical, and semen analysis data.
What is known already
Varicocele repair is recommended in the presence of a clinical varicocele together with at least one abnormal semen parameter, and male infertility. Unfortunately, up to 50% of men who meet criteria for repair will not see meaningful benefit in outcomes despite successful surgery. Nomograms exist to help predict success, but these are based out of single-center databases, do not incorporate hormonal data, and are rarely designed to predict pre-defined, clinically meaningful improvements in semen parameters.
Study design, size, duration
Data were collected from an international, multi-center retrospective cohort. A total of 240 men were identified. Data from 160 men from Miami, USA and 80 men from Toronto, Canada were included. Data was collected from 2006 to 2020.
Participants/materials, setting, methods
We collected pre and postoperative clinical data following varicocele surgery. Clinical upgrading was defined as an increase in sperm concentration that would allow a couple to access new reproductive technologies/techniques. The tiers used for upgrading were 0–1million/cc (Intracytoplasmic Sperm Injection), 1–5 million (In Vitro Fertilization), 5–15 million (Intrauterine Insemination), and >15 million (Natural conception). Artificial intelligence models were trained and tested using R to predict which patients upgraded after surgery.
Main results and the role of chance
51% of men underwent bilateral varicocele repair. The majority of men had grade 2 varicocele on the left, and (when present) a grade 1 varicocele on the right. Overall, 47% of men experienced an upgrade following varicocele surgery, 47% did not change, and 6% downgraded. The data from Miami were used to create a random forest model for predicting clinically significant upgrade in sperm concentration. The most informative model parameters were preoperative FSH, sperm concentration, and surgical laterality. The model identified three clinical categories: men with unfavorable, intermediate, and favorable features to predict varicocele upgrade. On external validation using data from Toronto, the model accurately predicted upgrade in 87% of men with favorable features, and in 49% and 36% of men with intermediate and unfavorable features, respectively. Overall, the model performed well on external validation with an AUC of 0.72 and good calibration.
Calibration plots, using cross-validation, define how well the predicted probabilities match the actual probability of sperm concentration upgrade. The random forest model was run twelve times. All model characteristics are the mean of ten model runs with the highest and lowest performing runs removed.
The model was translated to an online calculator that can be used by clinicians.
Limitations, reasons for caution
One limitation to our study is that we were not able to predict total motile sperm count (TMSC), which has been shown to perform slightly better than concentration at predicting assisted reproduction outcomes. By focusing on clinically significant upgrading, this difference should be minimized.
Wider implications of the findings: Predicting the chances of clinically significant semen upgrading after varicocele repair is essential for patients and clinicians to understand. Several men undergo surgery with no subsequent benefit, which may lead to a delay in definitive treatment with IVF/IUI. Understanding their chances will help couples make better informed decisions moving forward.
Trial registration number
Not applicable
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Affiliation(s)
- J Ory
- University of Miami, Department of Urology, Miami, USA
| | - M Tradewell
- University of Miami, Department of Urology, Miami, USA
| | - T Lima
- University of Miami, Department of Urology, Miami, USA
| | - U Blankstein
- University of Toronto, Department of Surgery- Division of Urology, Toronto, Canada
| | | | - J Moryousef
- McGill University, Faculty of Medicine, Montreal, Canada
| | - S Lau
- University of Toronto, Department of Surgery- Division of Urology, Toronto, Canada
| | - K Jarvi
- University of Toronto, Department of Surgery- Division of Urology, Toronto, Canada
| | - R Ramasamy
- University of Miami, Department of Urology, Miami, USA
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Best J, Kuchakulla M, Khodamoradi K, Lima T, Frech F, Achua J, Rosete O, Mora B, Arora H, Ibrahim E, Ramasamy R. P–070 Evaluation of SARS-CoV–2 in human semen and effect on total sperm number: A prospective observational study. Hum Reprod 2021. [PMCID: PMC8385871 DOI: 10.1093/humrep/deab130.069] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Study question Is the SARS-CoV–2 virus present in human semen and what is the impact on semen parameters following an infection? Summary answer SARS-CoV–2 infection, though not detected in semen of recovered men, can affect TSN in ejaculate in the acute setting. What is known already Early epidemiological data has suggested that the primary mode of transmission is through respiratory droplets, but the presence of SARS-CoV–2 has been identified in other bodily fluids such as feces, urine, and semen. Study design, size, duration We prospectively recruited thirty men diagnosed with acute SARS-CoV–2 infection using real-time reverse transcriptase-polymerase chain reaction (RT-PCR) of pharyngeal swab specimens. Thirty semen samples from recovered men were obtained 11–64 days after testing positive for SAR-CoV–2 infection. The median duration between positive SAR-CoV–2 test and semen collection was 37 days (IQR=23). Participants/materials, setting, methods Semen samples were collected from each individual using mailed kits. Follow-up semen samples were done with mailed kits or in-person in office setting. Semen analysis and PCR was performed after samples were received. Main results and the role of chance The median total sperm number (TSN) in ejaculate was 12.5 million (IQR=53.1). When compared with age-matched SARS-CoV–2(-) men, TSN was lower among SARS-CoV–2(+) men (p = 0.0024). Five men completed a follow-up sperm analysis (median 3 months) and had a median TSN of 18 million (IQR=21.6). No RNA was detected by means of RT-PCR in the semen in 16 samples tested. Limitations, reasons for caution First, most of the semen samples came from non-severe men of whom were in the recovery stage and lacked symptoms. Additionally, our sample size was relatively small and overnight mail-in semen analysis kits were used during the acute phase of infection to minimize contact with positive subjects. Wider implications of the findings: Our findings suggest extremely low risk of viral transmission during sexual contact and assisted reproductive techniques, although further data need to be obtained. The impact on TSC in recovered men from SARS-CoV–2 infection is concerning, nevertheless long-term follow-up of these men is critical to determine the nadir of TSC. Trial registration number 20200401
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Affiliation(s)
- J Best
- University of MIami, Urology, MIAMI, USA
| | | | | | - T Lima
- University of MIami, Urology, MIAMI, USA
| | - F Frech
- University of MIami, Urology, MIAMI, USA
| | - J Achua
- University of MIami, Urology, MIAMI, USA
| | - O Rosete
- University of MIami, Urology, MIAMI, USA
| | - B Mora
- University of MIami, Urology, MIAMI, USA
| | - H Arora
- University of MIami, Urology, MIAMI, USA
| | - E Ibrahim
- University of MIami, Urology, MIAMI, USA
| | - R Ramasamy
- University of MIami, Urology, MIAMI, USA
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Lima T, Martínez-Sogues L, Montserrat-Sangrà S, Solano-Gallego L, Ordeix L. Diagnostic performance of a qPCR for Leishmania on stained cytological specimens and on filter paper impressions obtained from cutaneous lesions suggestive of canine leishmaniosis. Vet Dermatol 2019; 30:318-e89. [PMID: 31135082 DOI: 10.1111/vde.12757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2019] [Indexed: 12/26/2022]
Abstract
BACKGROUND Detection of Leishmania in cutaneous lesions is possible by visualization of amastigotes. Detection of Leishmania DNA by PCR presents greater sensitivity, and PCR has been used to diagnose cutaneous leishmaniosis in humans using noninvasive clinical specimens. OBJECTIVES Study I: to determine if Leishmania DNA could be efficiently extracted and amplified from archived Diff-Quik® -stained slides of cytological specimens from canine cutaneous lesions. Study II: to evaluate the diagnostic performance of a Leishmania-quantitative (q)PCR on stained cytological specimens and on filter paper impressions (FPI) obtained from cutaneous lesions suggestive of canine leishmaniosis (CanL). ANIMALS Samples from cutaneous lesions of 54 dogs. METHODS AND MATERIALS Study I: Leishmania-qPCR was performed on 19 glass slides (from nine dogs) with cytologically visible amastigotes. Fifteen slides with no visible amastigotes, obtained from 12 dogs seronegative for Leishmania by ELISA, served as controls. Study II: Leishmania-qPCR was performed on glass slides and FPI from cutaneous lesions compatible with clinical leishmaniosis in 33 dogs. RESULTS Study I: all slides with visible amastigotes had positive qPCR, whereas all control slides yielded negative results. Study II: of 13 dogs definitively diagnosed with clinical leishmaniosis, eight had visible amastigotes on cytology, whereas Leishmania-qPCR was positive on 11 glass slides and 13 FPI. Leishmaniosis was ruled out by standard methods in 20 dogs, four of which yielded positive qPCR on FPI and/or glass slides. CONCLUSIONS AND CLINICAL IMPORTANCE Leishmania-DNA can be detected efficiently by qPCR from cutaneous cytological specimens and FPI to diagnose Leishmania infection in dogs with cutaneous lesions suggestive of CanL.
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Affiliation(s)
- Tatiana Lima
- Servei de Dermatologia, Fundació Hospital Clínic Veterinari, Carrer del Hospital, Campus de la Uab, 08193, Bellaterra, Barcelona, Spain.,Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, Edifici V, Campus de la Uab, 08193, Bellaterra, Barcelona, Spain
| | - Laura Martínez-Sogues
- Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, Edifici V, Campus de la Uab, 08193, Bellaterra, Barcelona, Spain.,Servei de Patologia Clínica, Fundació Hospital Clínic Veterinari, Carrer del Hospital, Campus de la Uab, 08193, Bellaterra, Barcelona, Spain
| | - Sara Montserrat-Sangrà
- Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, Edifici V, Campus de la Uab, 08193, Bellaterra, Barcelona, Spain
| | - Laia Solano-Gallego
- Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, Edifici V, Campus de la Uab, 08193, Bellaterra, Barcelona, Spain.,Servei de Patologia Clínica, Fundació Hospital Clínic Veterinari, Carrer del Hospital, Campus de la Uab, 08193, Bellaterra, Barcelona, Spain
| | - Laura Ordeix
- Servei de Dermatologia, Fundació Hospital Clínic Veterinari, Carrer del Hospital, Campus de la Uab, 08193, Bellaterra, Barcelona, Spain.,Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, Edifici V, Campus de la Uab, 08193, Bellaterra, Barcelona, Spain
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Batista KBDSL, Lima T, Palomares N, Carvalho FDA, Quintão C, Miguel JAM, Lin YL, Su TL, O'Brien K. Herbst appliance with skeletal anchorage versus dental anchorage in adolescents with Class II malocclusion: study protocol for a randomised controlled trial. Trials 2017; 18:564. [PMID: 29178932 PMCID: PMC5702230 DOI: 10.1186/s13063-017-2297-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 10/30/2017] [Indexed: 11/11/2022] Open
Abstract
Background The Herbst appliance is an orthodontic appliance that is used for the correction of class II malocclusion with skeletal discrepancies. Research has shown that this is effective. However, a potential harm is excessive protrusion of the lower front teeth. This is associated with gingival recession, loss of tooth support, and root resorption. This trial evaluates a method of reducing this problem. Methods/Design The study is a single-center, randomised, assessor-blinded, superiority clinical trial with parallel 1:1 allocation. Male and female young people (10–14 years old) with prominent front teeth (class II, division 1) will be treated in one orthodontic clinic. Group 1 will be treated with the conventional Herbst appliance with dental anchorage and group 2 with the Herbst appliance with indirect skeletal anchorage for 12 months. The primary objective will be to compare the proclination of the lower incisors between the Herbst appliance with dental anchorage and skeletal anchorage. Secondary objectives will be to evaluate the changes occurring between the groups in the mandible, maxilla, lower and upper molars, and in gingival recession and root resorption at the end of the treatment. Additionally, the young patient’s experience using the appliances will be assessed. The primary outcome measure will be the amount of lower incisor proclination at the end of treatment. This will be assessed by cone-beam computed tomography (CBCT) superimposition. Secondary outcome measures will be the changes in the mandible, maxilla, lower and upper molars at the end of treatment assessed by tomography superimposition and the young patient’s experience using the appliances assessed by self-reported questionnaires and semi-structured interviews. The randomisation method will be blocked randomisation, using software to generate a randomised list. The allocation concealment will be done in opaque envelopes numbered from 1 to 40 containing the treatment modality. The randomisation will be implemented by the secretary of the Department of Orthodontics of Rio de Janeiro State University before the beginning of the study. The patients and the orthodontists who will treat the patients cannot be blinded, as they will know the type of appliance used. The technician who will take the CBCT image and the data analyst will be blinded to patients’ group allocation. Discussion If this new intervention is effective, the findings can change orthodontic practice and may also be relevant to other forms of treatment in which appliances are fixed to the bones of the jaws. However, if the bone anchoring is not effective, the trial will provide much needed information on the use of this comparatively new development. Trial registration ClinicalTrials.gov, protocol ID: NCT0241812. Registered on 26 March 2015. Electronic supplementary material The online version of this article (doi:10.1186/s13063-017-2297-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Klaus Barretto Dos Santos Lopes Batista
- Division of Dentistry, Orthodontics, Universidade do Estado do Rio de Janeiro, Av. 28 de Setembro, 157, Vila Isabel, Rio de Janeiro, CEP: 20551-030, Brasil.
| | - Tatiana Lima
- Division of Dentistry, Universidade Veiga de Almeida, Rua Ibituruna, 108, Maracanã, Rio de Janeiro, CEP: 20271-020, Brasil
| | - Nathália Palomares
- Division of Dentistry, Orthodontics, Universidade do Estado do Rio de Janeiro, Av. 28 de Setembro, 157, Vila Isabel, Rio de Janeiro, CEP: 20551-030, Brasil
| | - Felipe de Assis Carvalho
- Division of Dentistry, Orthodontics, Universidade do Estado do Rio de Janeiro, Av. 28 de Setembro, 157, Vila Isabel, Rio de Janeiro, CEP: 20551-030, Brasil
| | - Cátia Quintão
- Division of Dentistry, Orthodontics, Universidade do Estado do Rio de Janeiro, Av. 28 de Setembro, 157, Vila Isabel, Rio de Janeiro, CEP: 20551-030, Brasil
| | - José Augusto Mendes Miguel
- Division of Dentistry, Orthodontics, Universidade do Estado do Rio de Janeiro, Av. 28 de Setembro, 157, Vila Isabel, Rio de Janeiro, CEP: 20551-030, Brasil
| | - Yin-Ling Lin
- Division of Dentistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Ting-Li Su
- Division of Oral Health Statistics, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Kevin O'Brien
- Division of Dentistry, Orthodontics, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
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Lima T, Von Zuben CJ. Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) Oviposition Behavior in Previous Oviposition Situation. Neotrop Entomol 2016; 45:612-617. [PMID: 27295050 DOI: 10.1007/s13744-016-0412-z] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 04/30/2016] [Indexed: 06/06/2023]
Abstract
Blowflies use their sense of smell to locate oviposition substrates and their vision to direct and assist in landing decision. Blowflies' ovipositions are usually aggregated. Chrysomya megacephala (Fabricius) females, for example, prefer to lay eggs on substrates containing fresh eggs of the same species. However, it is possible that females would be capable of evaluating the substrate, reducing the size of egg cluster in sites with a high amount of eggs or larvae, or finding another site for laying their eggs, preventing the progeny from facing high competition for space and food. The present study aimed to investigate whether females of C. megacephala could distinguish and preferentially select previously infested substrates and whether females would lay their eggs attached or separate from eggs previously laid on the substrate. Behavioral measures were conducted inside cages under laboratory conditions in free-choice tests. Data analysis confirmed that C. megacephala females are able to distinguish the presence of cospecific eggs in the substrate and preferentially select previously infested substrates for egg laying, depositing their eggs separate from pre-existing large egg masses.
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Affiliation(s)
- T Lima
- Lab of Entomology, Dept of Zoology, Univ Estadual Paulista "Júlio de Mesquita Filho" (UNESP), Campus de Rio Claro, Av. 24 A, 1515, Bela Vista, 13506-900, Rio Claro, SP, Brasil.
| | - C J Von Zuben
- Lab of Entomology, Dept of Zoology, Univ Estadual Paulista "Júlio de Mesquita Filho" (UNESP), Campus de Rio Claro, Av. 24 A, 1515, Bela Vista, 13506-900, Rio Claro, SP, Brasil
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Lima T, Silva HTD, Labuto G, Simões FR, Codognoto L. An Experimental Design for Simultaneous Determination of Carbendazim and Fenamiphos by Electrochemical Method. ELECTROANAL 2015. [DOI: 10.1002/elan.201500568] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Oliveira A, Magrini A, Carmo M, Passos P, Lima T, Momensohn-Santos T. History of Falls, Imbalance, and Vestibular Balance Tests of a Group Screened in a Health Social Fair. Int Arch Otorhinolaryngol 2014. [DOI: 10.1055/s-0034-1389015] [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: 10/23/2022] Open
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Oliveira A, Magrini A, Costa E, Figueiredo S, Lima T, Momensohn-Santos T. Cochlear Implant in Unilateral Hearing Loss: What Do the Professionals Think About? Int Arch Otorhinolaryngol 2014. [DOI: 10.1055/s-0034-1389057] [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: 10/23/2022] Open
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Abstract
Osler-Weber-Rendu syndrome is a very rare systemic fibrovascular dysplasia. Rupture of angiomas can cause haemorrhages, which sometimes can be severe with difficult bleeding control. The main manifestation is recurrent epistaxis. Treatment of this disorder is symptomatic. During pregnancy, there may be an increased risk of complications. We describe a case of a pregnant woman with Osler-Weber-Rendu syndrome. Besides frequent epistaxis and microcytic hypochromic anaemia that resolved with oral iron treatment, she had a normal pregnancy, vaginal delivery and puerperium without complications.
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Affiliation(s)
- G Inocêncio
- Obstetrics Gynaecology Department, Centro Hospitalar do Porto-Maternidade Júlio Dinis, Porto, Portugal.
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Prowse SJ, Lima T, Irion KL, Burhan H, Hochhegger B, Marchiori E. Valsalva manoeuvre effect on distribution of lung damage in heroin inhalation. Br J Radiol 2011; 84:e200-1. [PMID: 21933976 DOI: 10.1259/bjr/41925397] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
This article reports the case of a patient demonstrating acute bilateral pneumonitis almost completely confined to the upper lobes as a result of inhaling heroin. We attribute this distribution to the patient performing the Valsalva manoeuvre immediately after inhaling heroin. This pattern has not been reported before and we believe it may be seen more frequently owing to a switch amongst drug users from intravenous to inhaled heroin.
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Affiliation(s)
- S J Prowse
- Department of Radiology, Royal Liverpool Hospital, Liverpool, UK
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Longatto-Filho A, Roteli-Martins C, Hammes L, Etlinger D, Pereira SMM, Erzen M, Branca M, Naud P, Derchain SFM, Sarian LO, Matos J, Gontijo R, Lima T, Maeda MYS, Tatti S, Syrjänen S, Syrjänen K. Self-sampling for human papillomavirus (HPV) testing as cervical cancer screening option. Experience from the LAMS study. EUR J GYNAECOL ONCOL 2008; 29:327-332. [PMID: 18714563] [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: 05/26/2023]
Abstract
PURPOSE To compare Hybrid Capture II (HC2) in detecting high-risk (HR) HPV in patient-collected vaginal samples with those obtained using gynaecologist collected samples. METHODS Patients were submitted to Pap smears, visual inspection with acetic acid (VIA) and HC2 for hr-HPV. RESULTS A total of 1,081 HC2 tests for HR-HPV were performed: 770 (71.2%) samples were collected by a physician and 311 (28.8%) were self-collected by the patients. In detecting any cervical lesion, the sensitivity of HC2 collected by a physician was higher (92.86%) than that (37.5%) in the self-sampling group. Negative predictive value (NPV) was high for both, 99.69% and 93.75%, respectively. Using the CIN2 cutoff, performance of HC2 was significantly improved: 92.9% and 62.5%, respectively. HC2 specificity for any cervical lesion and for CIN2 or higher were close to 90% in both groups. CONCLUSIONS Self-sampled HPV testing is a powerful option to increase the detection of cervical lesions in women segregated from prevention programs.
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Longatto-Filho A, Erzen M, Branca M, Roteli-Martins C, Naud P, Derchain SFM, Hammes L, Sarian LO, Bragança JF, Matos J, Gontijo R, Lima T, Maeda MYS, Tatti S, Syrjänen S, Dores G, Lörincz A, Syrjänen K. Human papillomavirus testing as an optional screening tool in low-resource settings of Latin America: experience from the Latin American Screening study. Int J Gynecol Cancer 2006; 16:955-62. [PMID: 16803469 DOI: 10.1111/j.1525-1438.2006.00582.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [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: 11/26/2022] Open
Abstract
Hybrid capture II (HC II) test for oncogenic human papillomaviruses (HPV) was carried out in a cohort of 4284 women at their first clinical visit. Overall prevalence of HPV was 17.1%, decreasing with age from 33.9% among women below 20 years to only 11.0% among those older than 41 years. HPV prevalence was significantly higher among current smokers (odds ratio [OR] = 1.31; 95% CI 1.1-1.6), in women with two or more lifetime sexual partners (OR = 1.9; 95% CI 1.6-2.4), and those women with two or more sexual partners during the past 12 months prior to examination (OR = 1.6; 95% CI 1.2-2.2). HPV detection increased in parallel with increasing cytologic abnormality, being highest in women with high-grade squamous intraepithelial lesion (P= 0.001). Specificity of the HPV test in detecting histologically confirmed cervical disease was 85% (95% CI 83.9-86.1). Sensitivity of the HPV test in detecting histologic abnormalities increased in parallel with disease severity, ranging from 51.5% for cervical intraepithelial neoplasia (CIN) 1 to 96.5% for CIN 3 and 100.0% for cancer, with respective decline of positive predictive value. These data suggest that HPV testing with HC II assay might be a viable screening tool among this population with relatively high prevalence of cervical disease.
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Longatto-Filho A, Eržen M, Branca M, Roteli-Martins C, Naud P, Derchain SF, Hammes L, Sarian LO, Bragança JF, Matos J, Gontijo R, Lima T, Maeda MY, Tatti S, Syrjänen S, Dores G, LÖRINCZ A, Syrjänen K. Human papillomavirus testing as an optional screening tool in low-resource settings of Latin America: experience from the Latin American Screening study. Int J Gynecol Cancer 2006. [DOI: 10.1136/ijgc-00009577-200605000-00001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Hybrid capture II (HC II) test for oncogenic human papillomaviruses (HPV) was carried out in a cohort of 4284 women at their first clinical visit. Overall prevalence of HPV was 17.1%, decreasing with age from 33.9% among women below 20 years to only 11.0% among those older than 41 years. HPV prevalence was significantly higher among current smokers (odds ratio [OR] = 1.31; 95% CI 1.1–1.6), in women with two or more lifetime sexual partners (OR = 1.9; 95% CI 1.6–2.4), and those women with two or more sexual partners during the past 12 months prior to examination (OR = 1.6; 95% CI 1.2–2.2). HPV detection increased in parallel with increasing cytologic abnormality, being highest in women with high-grade squamous intraepithelial lesion (P = 0.001). Specificity of the HPV test in detecting histologically confirmed cervical disease was 85% (95% CI 83.9–86.1). Sensitivity of the HPV test in detecting histologic abnormalities increased in parallel with disease severity, ranging from 51.5% for cervical intraepithelial neoplasia (CIN) 1 to 96.5% for CIN 3 and 100.0% for cancer, with respective decline of positive predictive value. These data suggest that HPV testing with HC II assay might be a viable screening tool among this population with relatively high prevalence of cervical disease.
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Lima T, Bottino F, Calvelli P, Berardi C, Ajmone-Catt P, Molinatti GM, Limone P. [Primary hyperaldosteronism. Update on a topic of physiopathology and clinical features]. Minerva Med 1998; 89:411-8. [PMID: 10212665] [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: 02/12/2023]
Abstract
The authors examine the various forms of primary hyperaldosteronism, outlining the most recent acquisitions in terms of etiopathogenesis and physiopathology. While Conn's original description of primary hyperaldosteronism is a syndrome based on corticoadrenal aldosteronesecreting adenoma, it was later seen that this condition could recognise other anatomic substrates, such as carcinoma and in particular bilateral corticoadrenal hyperplasia. A peculiar form of the latter can be suppressed with glucocorticoids sustained by an anomalous recombination of aldosterone-synthase and 11-beta-hydroxylase. The main focus in this paper is on clinical management, in particular the current diagnostic criteria which show that primary hyperaldosteronism affects a higher percentage of the hypertense population that was estimated in the past. Above all, the significance of the aldosterone/PRA (ARR) ratio in screening for this condition is discussed, above all in normokalemic forms, together with the role of molecular biology in identifying glucocorticoid-suppressible forms. Lastly, the principles of medical and surgical management are outlined, emphasising the role of laparoscopic surgery.
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Affiliation(s)
- T Lima
- Dipartimento di Medicina Interna, Università degli Studi, Torino
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Limone P, Calvelli P, Altare F, Ajmone-Catt P, Lima T, Molinatti GM. Evidence for an interaction between alpha-MSH and opioids in the regulation of gonadotropin secretion in man. J Endocrinol Invest 1997; 20:207-10. [PMID: 9211127 DOI: 10.1007/bf03346904] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [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: 02/04/2023]
Abstract
Gonadotropin secretion is inhibited by the endogenous opioids and stimulated by their antagonist naloxone. LH secretion is stimulated by alpha-MSH, a tridecapeptide derived from the post-translational processing of POMC. The possibility that alpha-MSH interacts with the opioids, as suggested by the experimental evidence, was investigated in 7 normal males aged 24-29 through the performance of seven tests: naloxone (0.8 mg i.v. bolus, followed by infusion of 1.6 mg/h for 120'); alpha-MSH (2.5 mg i.v. bolus); naloxone + alpha-MSH (2.5 mg i.v. 15' after commencement of the naloxone infusion); naloxone + GnRH (100 micrograms i.v. 15' after commencement of the naloxone infusion); alpha-MSH + GnRH (respectively 2.5 mg and 100 micrograms at time 0), GnRH alone (100 micrograms at time 0), placebo (150 nmol/l NaCl solution). The LH AUCs during both naloxone (30.3 +/- 2.7 mIU/ml.min-1) and alpha-MSH test (32.9 +/- 4.6 mIU/ml.min-1) were significantly greater (p < 0.005) than that observed during placebo (16.9 +/- 3.6 mIU/ml.min-1). The LH AUC during alpha-MSH + naloxone (37.6 +/- 2.6 mIU/ml.min-1) was not significantly different from that recorded during their separate administration. GnRH injected alone, during the naloxone infusion and with alpha-MSH produced similar increases in LH, that were significantly higher than that observed during the other tests (AUCs: GnRH 89.4 +/- 10.6, GnRH + naloxone 100.5 +/- 9.1, GnRH + alpha-MSH 94.6 +/- 7.9 mIU/ml.min-1, p < 0.001). Significant increase in FSH (p < 0.001) was only observed during GnRH, GnRH + naloxone and GnRH + aMSH tests (AUCs: placebo 13.3 +/- 1.7; naloxone 14.7 +/- 2.5; alpha-MSH 15.5 +/- 2.3; alpha-MSH + naloxone 16.9 +/- 1.9; GnRH 19.1 +/- 1.1; GnRH + alpha-MSH 20.7 +/- 1.3; GnRH + naloxone 21.2 +/- 1.8 mIU/ml.min-1). These results are in line with the possibility of an interaction between alpha-MSH and the opioids in the regulation of gonadotropin secretion, perhaps with opposing effects on a final common pathway.
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Affiliation(s)
- P Limone
- Department of Internal Medicine, Regina Margherita Hospital, Torino, Italy
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Maas WK, Wang C, Lima T, Hach A, Lim D. Multicopy single-stranded DNA of Escherichia coli enhances mutation and recombination frequencies by titrating MutS protein. Mol Microbiol 1996; 19:505-9. [PMID: 8830241 DOI: 10.1046/j.1365-2958.1996.392921.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [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] [Indexed: 02/02/2023]
Abstract
Multicopy single-stranded DNA (msDNA) molecules consist of single-stranded DNA covalently linked to RNA. In Escherichia coli, such molecules are encoded by genetic elements called retrons. The DNA moieties of msDNAs have characteristic stem-loop structures, and most of these structures contain mismatched base pairs. Previously, we showed that retrons encoding msDNAs with mismatched base pairs are mutagenic when present in multicopy plasmids. In this study we show that such msDNAs, in a similar manner to genetic defects in mismatch repair, increase the frequency of interspecies recombination in matings between Salmonella typhimurium and E. coli. To demonstrate interference with mismatch repair by msDNA, we show that the addition of a plasmid containing the gene for MutS protein suppresses the mutagenic and recombinogenic effects of msDNAs. We also show that in mutS mutants, msDNA does not increase the frequency of either mutations or interspecies recombination. We conclude from these findings that the mutagenic and recombinogenic effects of msDNAs are due to titrating out MutS protein.
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Affiliation(s)
- W K Maas
- Department of Microbiology, New York University Medical Center, New York USA
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Abstract
Retrons are genetic elements that encode multicopy single-stranded DNAs called msDNAs. They are clonally distributed in Escherichia coli and retrons in different clones produce DNAs with different nucleotide sequences. msDNAs consist of an RNA molecule covalently linked to a single-stranded DNA molecule. The latter contains an inverted repeat, resulting in a stem-loop structure. In two retrons, Ec83 and Ec78, the DNA is cleaved off from the RNA. All known retrons except Ec78, have one or more mismatched base pairs in the stem-loop structure. We found that two retrons, Ec86 and Ec83, when present in high copy numbers are mutagenic. The ratios of mutation frequencies observed in Lac- indicator strains were similar to the ratios observed for a mutant defective in mismatch repair. It is known that some proteins required for mismatch repair bind to mismatched base pairs prior to carrying out repair. The similarity in the mutation frequency ratios suggested that the mutagenesis caused by msDNAs of retrons Ec86 and Ec83 might be due to sequestration of a mismatch repair protein by msDNA. Strong support for this interpretation was obtained from the finding that the msDNA produced by retron Ec78 is not mutagenic.
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Affiliation(s)
- W K Maas
- Department of Microbiology, New York University Medical Center, New York 10016
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