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1.
Nat Commun ; 15(1): 2054, 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38448430

RESUMO

Antibody engineering can tailor the design and activities of therapeutic antibodies for better efficiency or other advantageous clinical properties. Here we report the development of ISB 1442, a fully human bispecific antibody designed to re-establish synthetic immunity in CD38+ hematological malignancies. ISB 1442 consists of two anti-CD38 arms targeting two distinct epitopes that preferentially drive binding to tumor cells and enable avidity-induced blocking of proximal CD47 receptors on the same cell while preventing on-target off-tumor binding on healthy cells. The Fc portion of ISB 1442 is engineered to enhance complement dependent cytotoxicity, antibody dependent cell cytotoxicity and antibody dependent cell phagocytosis. ISB 1442 thus represents a CD47-BsAb combining biparatopic targeting of a tumor associated antigen with engineered enhancement of antibody effector function to overcome potential resistance mechanisms that hamper treatment of myeloma with monospecific anti-CD38 antibodies. ISB 1442 is currently in a Phase I clinical trial in relapsed refractory multiple myeloma.


Assuntos
Anticorpos Biespecíficos , Neoplasias Hematológicas , Mieloma Múltiplo , Humanos , Mieloma Múltiplo/tratamento farmacológico , Antígeno CD47 , Anticorpos Biespecíficos/farmacologia , Anticorpos Biespecíficos/uso terapêutico , Citotoxicidade Celular Dependente de Anticorpos
2.
J Bone Oncol ; 29: 100375, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34131559

RESUMO

Optimum management of patients with cancer during the COVID-19 pandemic has proved extremely challenging. Patients, clinicians and hospital authorities have had to balance the risks to patients of attending hospital, many of whom are especially vulnerable, with the risks of delaying or modifying cancer treatment. Those whose care has been significantly impacted include patients suffering from the effects of cancer on bone, where delivering the usual standard of care for bone support has often not been possible and clinicians have been forced to seek alternative options for adequate management. At a virtual meeting of the Cancer and Bone Society in July 2020, an expert group shared experiences and solutions to this challenge, following which a questionnaire was sent internationally to the symposium's participants, to explore the issues faced and solutions offered. 70 respondents, from 9 countries (majority USA, 39%, followed by UK, 19%) included 50 clinicians, spread across a diverse range of specialties (but with a high proportion, 64%, of medical oncologists) and 20 who classified themselves as non-clinical (solely lab-based). Spread of clinician specialty across tumour types was breast (65%), prostate (27%), followed by renal, myeloma and melanoma. Analysis showed that management of metastatic bone disease in all solid tumour types and myeloma, adjuvant bisphosphonate breast cancer therapy and cancer treatment induced bone loss, was substantially impacted. Respondents reported delays to routine CT scans (58%), standard bone scans (48%) and MRI scans (46%), though emergency scans were less affected. Delays in palliative radiotherapy for bone pain were reported by 31% of respondents with treatments often involving only a single dose without fractionation. Delays to, or cancellation of, prophylactic surgery for bone pain were reported by 35% of respondents. Access to treatments with intravenous bisphosphonates and subcutaneous denosumab was a major problem, mitigated by provision of drug administration at home or in a local clinic, reduced frequency of administration or switching to oral bisphosphonates taken at home. The questionnaire also revealed damaging delays or complete stopping of both clinical and laboratory research. In addition to an analysis of the questionnaire, this paper presents a rationale and recommendations for adaptation of the normal guidelines for protection of bone health during the pandemic.

3.
Mol Cancer ; 16(1): 49, 2017 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-28241871

RESUMO

Matrix metalloproteinases (MMPs) play a critical role in cancer pathogenesis, including tumor growth and osteolysis within the bone marrow microenvironment. However, the anti-tumor effects of MMPs are poorly understood, yet have significant implications for the therapeutic potential of targeting MMPs. Host derived MMP-7 has previously been shown to support the growth of bone metastatic breast and prostate cancer. In contrast and underscoring the complexity of MMP biology, here we identified a tumor-suppressive role for host MMP-7 in the progression of multiple myeloma in vivo. An increase in tumor burden and osteolytic bone disease was observed in myeloma-bearing MMP-7 deficient mice, as compared to wild-type controls. We observed that systemic MMP-7 activity was reduced in tumor-bearing mice and, in patients with multiple myeloma this reduced activity was concomitant with increased levels of the endogenous MMP inhibitor, tissue inhibitor of metalloproteinases-1 (TIMP-1). Our studies have identified an unexpected tumour-suppressive role for host-derived MMP-7 in myeloma bone disease in vivo, and highlight the importance of elucidating the effect of individual MMPs in a disease-specific context.


Assuntos
Neoplasias Ósseas/secundário , Metaloproteinase 7 da Matriz/genética , Metaloproteinase 7 da Matriz/metabolismo , Mieloma Múltiplo/patologia , Animais , Neoplasias Ósseas/genética , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Sobrevivência Celular , Progressão da Doença , Técnicas de Inativação de Genes , Humanos , Camundongos , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , Transplante de Neoplasias , Microambiente Tumoral
4.
Br J Cancer ; 116(2): 227-236, 2017 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-28006818

RESUMO

BACKGROUND: Recent evidence suggests that bone-related parameters are the main prognostic factors for overall survival in advanced prostate cancer (PCa), with elevated circulating levels of alkaline phosphatase (ALP) thought to reflect the dysregulated bone formation accompanying distant metastases. We have identified that PCa cells express ALPL, the gene that encodes for tissue nonspecific ALP, and hypothesised that tumour-derived ALPL may contribute to disease progression. METHODS: Functional effects of ALPL inhibition were investigated in metastatic PCa cell lines. ALPL gene expression was analysed from published PCa data sets, and correlated with disease-free survival and metastasis. RESULTS: ALPL expression was increased in PCa cells from metastatic sites. A reduction in tumour-derived ALPL expression or ALP activity increased cell death, mesenchymal-to-epithelial transition and reduced migration. Alkaline phosphatase activity was decreased by the EMT repressor Snail. In men with PCa, tumour-derived ALPL correlated with EMT markers, and high ALPL expression was associated with a significant reduction in disease-free survival. CONCLUSIONS: Our studies reveal the function of tumour-derived ALPL in regulating cell death and epithelial plasticity, and demonstrate a strong association between ALPL expression in PCa cells and metastasis or disease-free survival, thus identifying tumour-derived ALPL as a major contributor to the pathogenesis of PCa progression.


Assuntos
Fosfatase Alcalina/fisiologia , Proliferação de Células/genética , Transição Epitelial-Mesenquimal/genética , Neoplasias da Próstata/patologia , Neoplasias da Próstata/terapia , Fosfatase Alcalina/genética , Animais , Morte Celular/genética , Movimento Celular/genética , Células Cultivadas , Progressão da Doença , Intervalo Livre de Doença , Células HEK293 , Humanos , Masculino , Camundongos , Metástase Neoplásica , Neoplasias da Próstata/genética
6.
Br J Pharmacol ; 171(16): 3765-76, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24750110

RESUMO

Multiple myeloma is a neoplastic disorder of plasma cells characterized by clonal proliferation within the bone marrow. One of the major clinical features of multiple myeloma is the destructive osteolytic bone disease that occurs in the majority of patients. Myeloma bone disease is associated with increased osteoclast activity and suppression of osteoblastogenesis. Bisphosphonates have been the mainstay of treatment for many years; however, their use is limited by their inability to repair existing bone loss. Therefore, research into novel approaches for the treatment of myeloma bone disease is of the utmost importance. This review will discuss the current advances in our understanding of osteoclast stimulation and osteoblast suppression mechanisms in myeloma bone disease and the treatments that are under development to target this destructive and debilitating feature of myeloma.


Assuntos
Doenças Ósseas/tratamento farmacológico , Mieloma Múltiplo/tratamento farmacológico , Animais , Conservadores da Densidade Óssea/farmacologia , Conservadores da Densidade Óssea/uso terapêutico , Doenças Ósseas/etiologia , Doenças Ósseas/imunologia , Doenças Ósseas/metabolismo , Difosfonatos/farmacologia , Difosfonatos/uso terapêutico , Humanos , Fatores Imunológicos/farmacologia , Fatores Imunológicos/uso terapêutico , Mieloma Múltiplo/complicações , Mieloma Múltiplo/imunologia , Mieloma Múltiplo/metabolismo , Inibidores de Proteases/farmacologia , Inibidores de Proteases/uso terapêutico , Transdução de Sinais
7.
J Crohns Colitis ; 4(4): 405-12, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21122536

RESUMO

BACKGROUND: Inflammatory bowel disease (IBD), a paradigm of chronic illness, requires for its safe clinical management ready access to complete information, not always possible using paper records. AIM: To develop an IBD database (DB) for both individual patient management and collating information across centres. METHODS: Access® based, with a minimum dataset. RESULTS: Prospectively collected data for 11,432 patients from 21 centres. PROFILE DIAGNOSIS: Ulcerative colitis (UC) 56%, Crohn's disease (CD) 40%, indeterminate colitis 4%. M:F ratio: UC 1.08:1, CD 0.72:1. Median age at diagnosis: UC 39, CD 30 years. Operated: UC 16%, CD 47%. Thiopurine use: UC 16%, CD 29%. IBD related mortality: 0.74%. DISCUSSION: A snapshot of this large IBD cohort shows the disease profile across the UK is similar to other large series. Unexpected gaps, sometimes large emerged (e.g. data on smoking and immunosuppression) highlighting the need for clear definition, consistency and completeness of data collection. Clinical management is made easier by the 'at a glance' summary, automated clinic letters, and facility for monitoring and audit, but the time required limited its 'real-time' use. CONCLUSION: Our experience shows it is possible to collect data from centres across the country which truly reflects clinical practice. We have learned as much from the process itself as from the data, principally, information needs to be well defined, validated at entry, and updated at every visit, a time consuming sequence which we had underestimated. Our lessons learned may help inform the development of a national database, and support national IBD standards and audit.


Assuntos
Bases de Dados Factuais , Doenças Inflamatórias Intestinais/epidemiologia , Colectomia , Colite/tratamento farmacológico , Colite/epidemiologia , Colite/cirurgia , Colite/terapia , Colite Ulcerativa/epidemiologia , Colite Ulcerativa/terapia , Doença de Crohn/tratamento farmacológico , Doença de Crohn/epidemiologia , Doença de Crohn/cirurgia , Doença de Crohn/terapia , Coleta de Dados , Humanos , Imunossupressores/uso terapêutico , Doenças Inflamatórias Intestinais/tratamento farmacológico , Doenças Inflamatórias Intestinais/cirurgia , Doenças Inflamatórias Intestinais/terapia , Índice de Gravidade de Doença , Reino Unido/epidemiologia
8.
Leukemia ; 21(4): 805-12, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17315027

RESUMO

The growth and survival of myeloma cells is critically regulated by cells of the bone marrow microenvironment, including osteoblasts. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potent inducer of myeloma cell apoptosis, however, this antimyeloma activity is inhibited by osteoprotegerin (OPG) released from osteoblasts. Therefore, we hypothesized that specific agonists of TRAIL death receptors would not be inhibited by OPG released from osteoblasts and thus may represent a novel therapeutic approach in multiple myeloma. In the present study, TRAIL-induced apoptosis was demonstrated to be mediated through both DR4 and DR5. Specific agonist antibodies to DR4 or DR5 dose-dependently induced myeloma cell apoptosis, which was not prevented by OPG or by medium conditioned by osteoblasts. Co-culture of myeloma cells with osteoblasts protected against TRAIL-induced apoptosis of myeloma cells, and this protective effect was due to OPG. In contrast, the co-culture of myeloma cells with osteoblasts had no protective effect on apoptosis induced by specific agonists of DR4 or DR5. TRAIL has been proposed as a potential antitumour therapy, but within the bone marrow microenvironment OPG may interfere with the action of TRAIL. Specific agonists of TRAIL death receptors would not be subject to this inhibition and thus may provide an alternative specific antimyeloma therapy.


Assuntos
Apoptose/fisiologia , Células da Medula Óssea/fisiologia , Mieloma Múltiplo/patologia , Osteoprotegerina/farmacologia , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/efeitos dos fármacos , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/genética , Clorometilcetonas de Aminoácidos/farmacologia , Linhagem Celular Tumoral , Citometria de Fluxo , Regulação Neoplásica da Expressão Gênica , Humanos , Osteoblastos/efeitos dos fármacos , Osteoblastos/fisiologia , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/agonistas , Reação em Cadeia da Polimerase Via Transcriptase Reversa
11.
J Appl Physiol (1985) ; 95(4): 1598-605, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12857771

RESUMO

Submandibular secretory and vascular responses to stimulation of the parasympathetic innervation and the output of vasoactive intestinal peptide (VIP) were investigated in anaesthetized sheep in the presence and absence of atropine (>/=0.5 mg/kg). In the absence of atropine, parasympathetic stimulation caused an increase in the flow of saliva and a decrease in submandibular vascular resistance; the latter response persisted after the administration of atropine and was then significantly reduced at the lowest but not at the higher frequencies tested. The output of VIP from the gland was frequency dependent over the range of 10-20 Hz (continuously) and significantly increased after atropine (P < 0.02). Furthermore, the fall in vascular resistance was linearly related to log VIP output after total muscarinic blockade. Intracarotid infusions of synthetic VIP produced dose-dependent falls in submandibular vascular resistance, together with a corresponding increase in submandibular blood flow. It is concluded that the atropine-resistant vasodilatation that occurs in this gland during parasympathetic stimulation is likely to be due largely, if not entirely, to the release of VIP.


Assuntos
Sistema Nervoso Parassimpático/fisiologia , Glândula Submandibular/fisiologia , Animais , Atropina/farmacologia , Fenômenos Fisiológicos Cardiovasculares , Artérias Carótidas , Nervo da Corda do Tímpano/fisiologia , Relação Dose-Resposta a Droga , Resistência a Medicamentos , Estimulação Elétrica/métodos , Injeções Intra-Arteriais , Antagonistas Muscarínicos/farmacologia , Fluxo Sanguíneo Regional/efeitos dos fármacos , Saliva/efeitos dos fármacos , Saliva/metabolismo , Ovinos , Glândula Submandibular/irrigação sanguínea , Glândula Submandibular/metabolismo , Resistência Vascular , Peptídeo Intestinal Vasoativo/administração & dosagem , Peptídeo Intestinal Vasoativo/síntese química , Peptídeo Intestinal Vasoativo/metabolismo
12.
Endocrinology ; 142(10): 4244-50, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11564680

RESUMO

Oxyntomodulin is derived from proglucagon processing in the intestine and the central nervous system. To date, no role in the central nervous system has been demonstrated. We report here that oxyntomodulin inhibits refeeding when injected intracerebroventricularly and into the hypothalamic paraventricular nucleus of 24-h fasted rats [intracerebroventricularly and into the paraventricular nucleus, 1 h, oxyntomodulin (1 nmol), 3.1 +/- 0.5 g; saline, 6.2 +/- 0.4 g; P < 0.005]. In addition, oxyntomodulin inhibits food intake in nonfasted rats injected at the onset of the dark phase (intracerebroventricularly, 1 h: oxyntomodulin, 3 nmol, 1.1 +/- 0.19 g vs. saline, 2.3 +/- 0.2 g; P < 0.05). This effect of oxyntomodulin on feeding is of a similar time course and magnitude as that of an equimolar dose of glucagon-like peptide-1. Other proglucagon-derived products investigated [glucagon, glicentin (intracerebroventricularly, 3 nmol; into the paraventricular nucleus, 1 nmol), and spacer peptide-1 (intracerebroventricularly and into the paraventricular nucleus, 3 nmol)] had no effect on feeding at any time point examined. The anorectic effect of oxyntomodulin (intracerebroventricularly, 3 nmol; into the paraventricular nucleus, 1 nmol) was blocked when it was coadministered with the glucagon-like peptide-1 receptor antagonist, exendin-(9-39) (intracerebroventricularly, 100 nmol; into the paraventricular nucleus, 10 nmol). However, oxyntomodulin has a lower affinity for the glucagon-like peptide-1 receptor compared with glucagon-like peptide-1 (IC(50): oxyntomodulin, 8.2 nM; glucagon-like peptide-1, 0.16 nM). One explanation for this is that there might be an oxyntomodulin receptor to which exendin-(9-39) can also bind and act as an antagonist.


Assuntos
Regulação do Apetite/efeitos dos fármacos , Regulação do Apetite/fisiologia , Peptídeos Semelhantes ao Glucagon/farmacologia , Animais , Relação Dose-Resposta a Droga , Ingestão de Alimentos/efeitos dos fármacos , Masculino , Oxintomodulina , Ratos , Ratos Wistar
13.
Am J Physiol Endocrinol Metab ; 281(1): E155-61, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11404233

RESUMO

Exendin-4 is a long-acting potent agonist of the glucagon-like peptide 1 (GLP-1) receptor and may be useful in the treatment of type 2 diabetes and obesity. We examined the effects of an intravenous infusion of exendin-4 (0.05 pmol. kg(-1). min(-1)) compared with a control saline infusion in healthy volunteers. Exendin-4 reduced fasting plasma glucose levels and reduced the peak change of postprandial glucose from baseline (exendin-4, 1.5 +/- 0.3 vs. saline, 2.2 +/- 0.3 mmol/l, P < 0.05). Gastric emptying was delayed, as measured by the paracetamol absorption method. Volunteers consumed 19% fewer calories at a free-choice buffet lunch with exendin-4 (exendin-4, 867 +/- 79 vs. saline 1,075 +/- 93 kcal, P = 0.012), without reported side effects. Thus our results are in accord with the possibility that exendin-4 may be a potential treatment for type 2 diabetes, particularly for obese patients, because it acts to reduce plasma glucose at least partly by a delay in gastric emptying, as well as by reducing calorie intake.


Assuntos
Glicemia/metabolismo , Ingestão de Energia/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Lagartos/fisiologia , Peptídeos/farmacologia , Peçonhas/farmacologia , Acetaminofen/sangue , Adulto , Analgésicos não Narcóticos/sangue , Animais , Área Sob a Curva , Depressão Química , Exenatida , Jejum/metabolismo , Feminino , Esvaziamento Gástrico/efeitos dos fármacos , Glucagon/sangue , Peptídeo 1 Semelhante ao Glucagon , Hormônios/sangue , Humanos , Infusões Intravenosas , Insulina/sangue , Masculino , Náusea/induzido quimicamente , Fragmentos de Peptídeos/sangue , Peptídeos/administração & dosagem , Peptídeos/efeitos adversos , Período Pós-Prandial/efeitos dos fármacos , Período Pós-Prandial/fisiologia , Precursores de Proteínas/sangue , Resposta de Saciedade/efeitos dos fármacos , Peçonhas/administração & dosagem , Peçonhas/efeitos adversos
14.
Br J Surg ; 87(8): 1063-6, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10931051

RESUMO

BACKGROUND: The faecal stream plays a significant role in the pathogenesis of Crohn's disease. This retrospective study aimed to assess the effect of faecal diversion on the natural history of refractory Crohn's colitis (RCC) and severe perianal disease (PAD). METHODS: All patients undergoing a defunctioning stoma without resection for RCC or PAD between 1970 and 1997 were studied. Indications for surgery, acute clinical response, subsequent outcome and stoma rates were recorded. RESULTS: Some 73 patients underwent a defunctioning stoma (55 RCC and 18 PAD). Acute remission was achieved in 63 patients (48 RCC, 15 PAD). Twenty-nine patients had subsequent closure of the defunctioning stoma (25 of 48 acute responders with RCC and four of 15 acute responders with PAD). Eleven patients with RCC and two with PAD achieved good long-term function without disease relapse (median follow-up 36 months). Overall 52 patients have undergone proctocolectomy or remain with a defunctioning stoma (37 with RCC and 15 with PAD). CONCLUSION: Faecal diversion is associated with acute clinical remission in the majority of patients with RCC and PAD, but sustained benefit occurs less often. For selected patients, diversionary surgery alone offers a realistic alternative to major bowel resection.


Assuntos
Doença de Crohn/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anastomose Cirúrgica/métodos , Doença Crônica , Colostomia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proctocolectomia Restauradora/métodos , Recidiva , Estudos Retrospectivos , Resultado do Tratamento
15.
Am J Physiol Endocrinol Metab ; 278(6): E1060-6, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10827009

RESUMO

Intravenous injection of galanin increases plasma growth hormone (GH) and prolactin (PRL) concentrations. In the rat, the effects of galanin on GH appear to be mediated via the hypothalamic galanin receptor GAL-R(1), at which galanin-(3-29) is inactive. In contrast, the effect of galanin on PRL is mediated via the pituitary-specific galanin receptor GAL-R(W), at which galanin-(3-29) is fully active. We investigated the effects of an intravenous infusion of human galanin (hGAL)-(1-30) and -(3-30) on anterior pituitary hormone levels in healthy females. Subjects were infused with saline, hGAL-(1-30) (80 pmol. kg(-1). min(-1)), and hGAL-(3-30) (600 pmol. kg(-1). min(-1)) and with boluses of gonadotropin-releasing hormone, thyrotropin-releasing hormone, and growth hormone-releasing hormone (GHRH). Both hGAL-(1-30) and -(3-30) potentiated the rise in GHRH-stimulated GH levels [area under the curve (AUC), saline, 2,810 +/- 500 vs. hGAL-(1-30), 4,660 +/- 737, P < 0.01; vs. hGAL-(3-30), 6, 870 +/- 1,550 ng. min. ml(-1), P < 0.01]. In contrast to hGAL-(1-30), hGAL-(3-30) had no effect on basal GH levels (AUC, saline, -110 +/- 88 vs. hGAL 1-30, 960 +/- 280, P < 0.002; vs. hGAL-(3-30), 110 +/- 54 ng. min. ml(-1), P = not significant). These data suggest that the effects of galanin on basal and stimulated GH release are mediated via different receptor subtypes and that the human equivalent of GAL-R(W) may exist.


Assuntos
Galanina/farmacologia , Fragmentos de Peptídeos/farmacologia , Hormônios Adeno-Hipofisários/metabolismo , Adulto , Pressão Sanguínea/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Feminino , Galanina/administração & dosagem , Galanina/sangue , Hormônio Liberador de Gonadotropina , Frequência Cardíaca/efeitos dos fármacos , Hormônio do Crescimento Humano/sangue , Humanos , Infusões Intravenosas , Cinética , Hormônio Luteinizante/sangue , Fragmentos de Peptídeos/administração & dosagem , Prolactina/sangue , Tireotropina/sangue , Hormônio Liberador de Tireotropina
16.
Exp Physiol ; 84(6): 1107-13, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10564707

RESUMO

The role of nitric oxide (NO) in mediating pancreatic endocrine responses to moderate hypoglycaemia has been investigated in conscious unrestrained calves. The synthesis of endogenous NO was inhibited by the administration of N-nitro-L-arginine methyl ester (L-NAME; 100 mg kg-1 I.A.), while sodium nitroprusside was infused continuously (2-4 microg min-1 kg-1 I.V.) to mimic the tonic production of NO. This effectively abolished the rise in plasma pancreatic polypeptide (PP) concentration during moderate hypoglycaemia (0.7 nmol kg-1 insulin I.V.) and significantly reduced the response to more intense hypoglycaemia (2.0 nmol kg-1 insulin I. V.). In contrast, the glucagon response was not significantly affected in either group, although consistently higher plasma glucagon values were obtained in response to the higher dose of insulin following the administration of L-NAME. It is concluded that, in the absence of L-NAME, production of NO contributes to the PP response, but not the glucagon response to hypoglycaemia in this species under physiological conditions.


Assuntos
Hipoglicemia/induzido quimicamente , Insulina/farmacologia , Óxido Nítrico/metabolismo , Pâncreas/metabolismo , Animais , Glicemia/metabolismo , Pressão Sanguínea/efeitos dos fármacos , Bovinos , Glucagon/sangue , Frequência Cardíaca/efeitos dos fármacos , NG-Nitroarginina Metil Éster/farmacologia , Nitroprussiato/farmacologia , Polipeptídeo Pancreático/sangue
19.
J Endocrinol ; 160(3): R7-12, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10077743

RESUMO

Orexin-A and orexin-B (the hypocretins) are recently described neuropeptides suggested to have a physiological role in the regulation of food intake in the rat. We compared the orexigenic effect of the orexins administered intracerebroventricular (ICV) with other known stimulants of food intake, one strong, neuropeptide Y (NPY), and two weaker, melanin-concentrating hormone (MCH) and galanin. Orexin-A consistently stimulated food intake, but orexin-B only on occasions. Both peptides stimulated food intake significantly less than NPY, but to a similar extent to MCH (2 h food intake: NPY 3 nmol, 7.2+/-0.9 g vs saline, 1.5+/-0.2 g, P<0.001, MCH 3 nmol, 3.2+/-0.8 g vs saline, P<0.01, orexin-B 30 nmol, 2. 6+/-0.5 g vs saline, P=0.11) and to galanin (1 h food intake: galanin 3 nmol, 2.0+/-0.4 g vs saline, 0.8+/-0.2 g, P<0.05, orexin-A 3 nmol 2.2+/-0.4 g vs saline, P<0.01; 2 hour food intake: orexin-B 3 nmol, 2.4+/-0.3 g vs saline, 1.3+/-0.2 g, P<0.05). Following ICV orexin-A, hypothalamic c-fos, a maker of neuronal activation, was highly expressed in the paraventricular nucleus (PVN), and the arcuate nucleus (P<0.005 for both). IntraPVN injection of orexin-A stimulated 2 h food intake by one gram (orexin-A 0.03 nmol, 1.6+/-0. 3 g vs saline, 0.5+/-0.3 g, P<0.005). These findings support the suggestion that the orexins stimulate food intake. However, this effect is weak and may cast doubt upon their physiological importance in appetite regulation in the rat.


Assuntos
Ingestão de Alimentos/efeitos dos fármacos , Hipotálamo/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular , Neuropeptídeos/farmacologia , Animais , Proteínas de Transporte/farmacologia , Galanina/farmacologia , Expressão Gênica/efeitos dos fármacos , Genes fos , Hormônios Hipotalâmicos/farmacologia , Masculino , Melaninas/farmacologia , Neuropeptídeo Y/farmacologia , Orexinas , Hormônios Hipofisários/farmacologia , Ratos , Ratos Wistar
20.
Histopathology ; 34(1): 1-5, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9934577

RESUMO

Diversion proctocolitis is an iatrogenic disorder caused by surgical diversion of the faecal stream away from the colorectal mucosa. Such surgery may be necessary in cases of tumour, trauma or inflammatory conditions of the colorectum. Histopathological change is characterized by a chronic lymphoplasmacytic inflammatory infiltrate, and the hallmark feature, lymphoid follicular hyperplasia. Histological appearances are determined by the disease state of the colonic mucosa prior to faecal diversion. Macroscopic appearances may vary considerably, but often include aphthoid ulceration. The exact pathogenesis of the condition remains unclear, but the removal of short-chain fatty acids, present in the faecal stream, is considered an important aetiological factor. Current research areas, including the microbiology and cellular kinetics of diversion colitis, are discussed along with clinical features and treatments.


Assuntos
Colite/imunologia , Colite/patologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/patologia , Bactérias/isolamento & purificação , Bactérias/metabolismo , Colectomia/efeitos adversos , Colite/etiologia , Colite/microbiologia , Colite Ulcerativa/patologia , Colo/imunologia , Colo/microbiologia , Colo/patologia , Doença de Crohn/patologia , Ácidos Graxos Voláteis/metabolismo , Ácidos Graxos Voláteis/fisiologia , Humanos , Hiperplasia/patologia , Mucosa Intestinal/microbiologia
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