A Framework for Generalising the Newton Method and Other Iterative Methods from Euclidean Space to Manifolds

The Newton iteration is a popular method for minimising a cost function on Euclidean space. Various generalisations to cost functions defined on manifolds appear in the literature. In each case, the convergence rate of the generalised Newton iteration needed establishing from first principles. The present paper presents a framework for generalising iterative methods from Euclidean space to manifolds that ensures local convergence rates are preserved. It applies to any (memoryless) iterative method computing a coordinate independent property of a function (such as a zero or a local minimum). All possible Newton methods on manifolds are believed to come under this framework. Changes of coordinates, and not any Riemannian structure, are shown to play a natural role in lifting the Newton method to a manifold. The framework also gives new insight into the design of Newton methods in general.Comment: 36 page

Pancreatite Hipertrigliceridémica: Tratamento Convencional Versus Troca Plasmática Terapêutica

Introduction: Acute pancreatitis (AP) induced by hypertriglyceridemia (HTG) can be treated with therapeutic plasma exchange (TPE), resulting in rapid reduction of triglyceride level. However, there are no definitive comparative studies that prove the real benefits of this therapy. Objectives: Comparison of treatment methods (TPE versus conventional) in patients with HTG AP during a period of 12 years (2000-2012). Methods: Retrospective, descriptive and inferential analysis of 37 patients, evaluating: gender, age, personal pathologic history, severity of disease, HTG values and evolution depending on treatment with therapeutic plasma exchange (“TPE”) or with conventional therapy (“C”). Results: Both groups TPE and C demonstrated homogeneity considering gender (p = 0.647), age (43.5 ± 9.74 years TPE vs 45.30 ± 9.90 years C; p = 0.320), prior AP episode (40% TPE vs 40.7% C; p = 1.0), chronic alcohol consumption (50% TPE vs 70.4% C; p = 0.275) and severity disease scores: APACHE II (p = 0.054) and Ranson (p = 0.258). More than one secondary HTG risk factor was presented in 45.95% of patients . TPE group presented higher TG levels at admission: 4850 ± 2802 mg/dL vs 1845 ± 1858 mg/dL (p = 0.001). No significant statistical differences were observed considering length of hospital stay [14.2 ± 6.8 days vs 13.5 ± 9.0 days (p = 0.56)] or mortality rate (p = 0.47). At discharge, TG reduction was greater in TPE group: 4433.70 ± 2896.08 mg/dL – 91.41% vs 1582.95 ± 2051.06 mg/dL – 83,92% (p = 0.002). Six minor complications associated to TPE occurred. Discussion/Conclusion: Despite the selection bias (retrospective study), a greater TG reduction was observed with TPE technique. Complications associated with the technique were simple to resolveinfo:eu-repo/semantics/publishedVersio

Hypertriglyceridemic Pancreatitis: Conventional Treatment Versus Therapeutic Plasma Exchange

Introdução:A pancreatite aguda (PA) por hipertrigliceridemia (HTG) pode ser tratada com troca plasmática terapêutica (TPT), com redução rápida dos valores de triglicerídeos. Contudo, não existem estudos comparativos definitivos que comprovem o real benefício desta terapêutica. Objetivo: Comparação dos métodos de tratamento (troca plasmática terapêutica versus convencional) em doentes com PA HTG, durante um período de 12 anos (2000-2012). Métodos: Estudo retrospetivo descritivo e inferencial de 37 doentes, avaliando: sexo, idade, antecedentes pessoais, gravidade, valores de TG e evolução consoante o tratamento (“TPT” ou terapêutica convencional “C”). Resultados: Os dois grupos TPT e C mostraram-se homogéneos quanto ao sexo (p = 0,647), idade (43,5 ± 9,74 anos TPT versus 45,30 ± 9,90 anos C; p = 0.320), pancreatite prévia (40% TPT vs 40,7% C; p = 1,0) alcoolismo crónico (50% TPT vs 70,4% C; p = 0,275) e gravidade pelo score de APACHE II (p = 0,054) e Ranson às 48 horas (p = 0,258). Dos doentes 45,95% apresentava mais de um fator de risco secundário para HTG. O grupo TPT apresentou maiores valores de TG à admissão: 4850 ± 2802 mg/dL vs 1845 ± 1858 mg/dL (p = 0,001). Não se verificaram diferenças na duração do internamento 14,2 ± 6,8 dias vs 13,5 ± 9,0 dias (p = 0,56) ou na taxa de mortalidade (p = 0,47). À data de alta a redução dos TG foi superior no grupo TPT: 4433,70 ± 2896,08 mg/dL - 91,41% vs 1582,95 ± 2051,06 mg/dL – 83,92% (p = 0,002). De referir seis intercorrências minor durante a troca plasmática terapêutica. Discussão/Conclusões: Apesar do viés de seleção (estudo retrospetivo), foi constatada uma maior redução dos TG por esta técnica. As intercorrências inerentes à técnica de troca plasmática terapêutica foram de simples resolução.info:eu-repo/semantics/publishedVersio

Immunology and mammary cancer development: addressing the role of mast cells

Background: Mammary cancer is one of the most frequent cancers worldwide. Mast cells are among the cells of tumor microenvironment and have been associated with increased angiogenesis and poor prognosis. Despite this, the role of mast cells on mammary cancer is not fully elucidated. In this way, this work studied the role of mast cells in a rat model of mammary cancer chemically-induced. Materials and Methods: All experiments were performed in accordance with the Portuguese and European legislation on the protection of animals used for scientific purposes. The experiments were approved by the Portuguese (no.008961) and University (CE_12-2013) Ethics Committees. Thirty- four female Sprague-Dawley rats were randomly divided into five experimental groups. At seven weeks of age, mammary tumors’ development was induced in animals from groups I, II, III (n = 10+10+10) by a single intraperitoneal injection of the carcinogen N-methyl-N-nitrosourea (MNU). Groups II and IV (n = 2) were treated with ketotifen in drinking water (1 mg/kg/day, 7 days/week) immediately after the MNU ad- ministration for 18 weeks, while the group III received the ketotifen after the development of the first mammary tumor. Groups I and V (n = 2) received only water. Animals were sacrificed at 25 weeks of age by an overdose of ketamine and xylazine, followed by an exsanguination by cardiac puncture. Mammary tumors were collected and immersed in formalin for posterior analysis. Tumors’ vascularization, proliferation and apoptosis were also assessed by immunohistochemistry (Vascular Endothelial Growth Factor (VEGF)-A, Ki-67, and caspase-3 and caspase-9). Results: Animals from groups IV and V did not develop any mammary tumor. Twenty-one animals (six animals from group I, eight animals from group II and seven animals from group III) developed a total of 58 mammary tumors, mainly classified as papillary non-invasive carcinomas. Tumors’ vascularization was similar among groups (P > 0.05). Mammary tumors from group II exhibited the lowest prolif- eration (P < 0.05) and apoptotic indexes. Conclusions: The mainly positive effect of the ketotifen administration seems to be the reduction of tumor prolifera- tion when the drug was administered before mammary tumor development

The influence of physical exercise on oestrogen and androgen receptor expression in a chemically and hormonally-induced rat model of prostate cancer

Background: Oestrogen (ER) and androgen (AR) recep- tors play an important role in normal prostate development and are also implied in prostate cancer (PCa) development. Several studies suggested that physical activity may decrease the risk of PCa development and also changes sexual hor- mones and their receptors. This study aimed to evaluate the effects of physical exercise on ERα and AR expression in a rat model of chemically and hormonally-induced PCa. Materials and Methods: Fifty-five male Wistar Unilever rats of 12 weeks of age were randomly divided into four groups: control sedentary (n = 10), control exercised (n = 10), induced sedentary (n = 15) and induced exercised (n = 20). Animals from exercised groups started the exercise training in a treadmill (Treadmill Control LE 8710, Harvard Apparatus, USA), at the age of 8 weeks, for 35 weeks (5 days/week). The protocol for PCa induction started at 12 weeks of age and consisted of sequential administration of flutamide (50 mg/kg, TCI Chemicals), testosterone propion- ate (100 mg/kg, TCI Chemicals) and N-methyl-N-nitrosourea (30 mg/kg, Isopac®, Sigma Chemical Co.), followed by sub- cutaneous implants of crystalline testosterone. Animals were sacrificed at 61 weeks of age and a complete necropsy was performed. All experiments were approved by DGAV (no. 021326). Antibodies for Erα (1:500, clone 6F11, Novocastra) and AR (clone PG21, Merck Millipore) were used for the immunohistochemical study. The staining extension was evaluated in normal prostate tissue and in dorsolateral pros- tate lesions (hyperplasia, dysplasia, prostatic intraepithelial neoplasia (PIN) and microinvasive carcinoma) and assessed to five levels (0%, 75%), con- sidering the extension of immunopositive tissue. Data was analysed with SPSS 25.Results: The normal prostate tissue and dorsolateral prostate lesions of animals from all groups were immunopositive for Erα and AR. However, the groups showed high immunoposi- tivity for AR and low positivity for Erα ( 0.05). The malignant lesions (PIN and microinvasive carcinoma) showed lower AR expression when compared with normal prostate tissue in all groups. Conclusions: As expected, the AR expression was lower in malignant lesions. Inversely to that reported in other studies, the exercise training did not modify the ERα and AR expres- sion, which may be related to the duration and type of exer- cise performed

Effects of physical exercise in biochemical parameters and dorsolateral prostate lesions: data from a rat model of prostate cancer

Background: Prostate cancer (PCa) is among the most prevalent cancers worldwide. Physical exercise is widely recognized due to its beneficial effects. This study aimed to evaluate the effects of physical exercise on biochemical pa- rameters and in dorsolateral prostate lesions in a rat model of PCa. Materials and Methods: Ninety-five male Wistar Unilever rats were randomly divided into eight groups sacrificed at 35 (groups I) or 61 weeks of age (groups II): control sedentary groups (Cont+Sed I (n = 10); Cont+Sed II (n = 10)); induced sedentary group (PCa+Sed I (n = 10); PCa+Sed II (n = 15)); control exercised groups (Cont+EX I (n = 10); Cont+EX II (n = 10)) and induced exercised groups (PCa+EX I (n = 10); PCa+EX II (n = 20)). All procedures were approved (DGAV, no. 021326). Animals from exercised groups started the exer- cise program in a treadmill at 8 weeks of age, for 28 weeks or 53 weeks. The animals were trained 5 days/week, 60 min per day. Prostate lesions were induced at 12 weeks of age, with sequential administration of flutamide, testosterone propion- ate and N-methyl-N-nitrosourea, and subcutaneous implants of crystalline testosterone. Animals were sacrificed at 35 or 61 weeks of age. Peripheral blood of all animals was col- lected by intracardiac puncture. A complete necropsy was performed. The dorsolateral prostate tissues sections were processed for histological analysis. Data were analysed using SPSS 25. p 0.05). Dorsolateral prostate lesions were classified as dysplasia, prostatic intraep- ithelial neoplasia (PIN) and microinvasive carcinoma. The number of prostate lesions was higher in animals from groups II than in those from groups I, mainly in PCa+Sed II animals when compared with PCa+Sed I (p 0.05). Conclusions: Overall, the animals sacrificed at 61 weeks of age developed more dorsolateral prostate lesions than ani- mals sacrificed at 35 weeks of age, which may be related to a longer testosterone exposure

How we survived: older adults’ adjustment to the lockdowns due to the COVID-19 pandemic

Objective: Older adults were found to be the most susceptible group to suffer the physical health consequences of a COVID-19 infection and were considered vulnerable to the negative effects of the lockdowns due to the COVID-19 pandemic, yet unlike many young adults did not generally experience an increased rate of mental health problems. Our study explored the strategies older adults in Portugal deployed during the mandatory lockdowns in 2020 and 2021. Methods and Measures: Qualitative interview data were collected with 22 older adults in relatively good health (aged between 66 and 92 years old; 36% women). Results: Three main themes were identified via thematic analysis: 1) Finding things to do and activities that can protect me; 2) Identifying how my thoughts can protect me; and 3) Counting myself lucky – me and my home advantages. Conclusion: Some of the thematic strategies identified by older adults to manage pandemic and lockdown-related stresses related to meaning-centered coping could be further developed via cognitive behavioral therapies of the third wave

Rat prostate: practical tips for ultrasonographic monitoring

Background: Prostate is the largest accessory gland of the male reproductive tract. The prostate of men over 40 years- old is frequently affected by several pathologies, like benign prostate hyperplasia and cancer. Rats have been used as model to study prostate cancer. This study intended to address the usefulness of ultrasonography for rat prostate monitoring. Materials and Methods: Eight male Wistar Unilever rats were acquired from Charles River Laboratories and main- tained under controlled conditions of temperature, humidity, air system filtration and light/dark cycle. The prostate was evaluated by ultrasonography in awake animals. The animals were restrained by a researcher and placed in supine position. The skin of the inguinal region was shaved using a machine clipper (AESCULAP® GT420 Isis, USA). A real-time scan- ner (Logic P6®, GE, USA) and a 12 MHz linear transducer were used. Acoustic gel (Parker Laboratories Inc., USA) was applied. A complete transverse scan using B mode was per- formed from the cranial to the caudal region of the prostate, and a sagittal scan was performed moving the probe from the right to the left side. Procedures were approved by the Portuguese Ethics Committee (no.021326). Results: Prostate was easily evaluated by ultrasonography in all animals. In the transverse scan, the urinary bladder presents as a round to oval shape filled with urine (anechoic structure) and the prostate lobes were visible around it. The ventral prostate lobes appear as hypoechoic elongated struc- tures (one right and one left) with a hyperechoic capsule, placed ventrally to the urinary bladder. In this scan, the dorsal prostate was observed close to the urinary bladder neck, as a round hypoechoic structure with a hyperechoic capsule, dor- sally to the urinary bladder. In the sagittal scan, the urinary bladder was observed as an elongated structure filled with urine (anechoic content). The ventral prostate lobes were occasionally observed ventrally to the neck of the urinary bladder, as previously described. The dorsal prostate was ob- served dorsally to the neck of the urinary bladder, presenting as a round to elongated shape, with a hypoechoic appearance and a hyperechoic capsule.Conclusions: The ultrasonography is a non-invasive and ac- cessible tool for prostate monitoring in the rat model. Acknowledgments: This work was supported by European Investment Funds by FEDER/ COMPETE/POCI - Operational Competitiveness and Internationalization Program and National Funds by FCT - Portuguese Foundation for Science and Technology, under the projects Project RUNawayPCa (POCI-01-0145-FEDER-016728 and PTDC/DTP-DES/6077/2014), UIDB/04033/2020, UIDB/ CVT/00772/2020 and UIDB/50006/2020 (LAQV)