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1.
Vet J ; 305: 106143, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38788997

ABSTRACT

T-zone-like cells of undetermined significance (TZUS) share the same phenotypic pattern (CD45-CD5+) with T-zone lymphoma cells and were first described a few years ago in the peripheral blood (PB) of healthy aged American Golden retrievers (GR). History of bladder and eye disease increased the odd of circulating TZUS in the American GR population. Since differences among dogs may exist according to the geographical region of origin, herein we screened 489 PB samples to assess potential factors predisposing to the presence of circulating TZUS in dogs living in Italy. Overall, TZUS were found in 174 (35.6%) samples. Among 83 clinical variables, significant associations emerged with sex, age, diagnosis of neoplasia, history of neoplasia, history of infectious or parasitic disease, history of osteoarticular disease, presence of traumatic lesions or foreign bodies, and lymphocytes count. Only age and history of neoplasia retained significance at multivariate analysis (p=0.019 and p=0.036, respectively). Thus, older age and history of neoplasia are the main factors associated with circulating TZUS in Italian dogs. Future studies should focus on elucidating the biological role of TZUS and determining reproducible criteria for their identification, distinguishing them from infiltrating TZL.


Subject(s)
Dog Diseases , Animals , Dogs , Italy/epidemiology , Dog Diseases/epidemiology , Dog Diseases/blood , Female , Male
2.
J Small Anim Pract ; 64(9): 561-567, 2023 09.
Article in English | MEDLINE | ID: mdl-37186237

ABSTRACT

OBJECTIVES: To review clinical characteristics, treatment, outcome and prognostic factors in dogs with solid cancer-bearing bone metastases. MATERIALS AND METHODS: Records were reviewed from dogs with histologically-proven solid cancer and bone metastases. Clinicopathologic variables, bone metastases characteristics and skeletal-related events were recorded. Endpoints were time to bone metastases and survival. RESULTS: Fifty dogs were included, 20 of them with synchronous and 30 of them with metachronous bone metastases. In the latter group, median time to diagnosis of bone metastases was 210 days (range, 30 to 1835). Most common primary cancer locations included mammary gland (n=6), spleen (n=5) and tonsil (n=5). Most common histotypes were carcinoma (n=32) and hemangiosarcoma (n=10). Nineteen dogs had multiple bones involvement, with humeri and vertebrae more commonly affected. Twenty-four dogs received antitumoural therapy, five symptomatic treatment and 21 were not treated. Overall median survival after bone metastases diagnosis was 30 days (range, 11 to 49); 83% of dogs died because of skeletal-related events. Lack of antitumoural therapy was significantly associated with shorter survival (hazard ratio: 2.7; 95% confidence interval: 1.3 to 5.6) and with increased risk of skeletal-related death (hazard ratio: 3.3; 95% confidence interval: 1.4 to 7.4). Dogs with endocrine/neuroendocrine tumours (odds ratio: 8.8; 95% confidence interval: 1.2 to 63.9), without appendicular metastases (odds ratio: 5.1; 95% confidence interval: 1.0 to 25.8), without extra-skeletal metastases (odds ratio: 5.2; 95% confidence interval: 1.1 to 24.5) and receiving antitumoural therapy (odds ratio: 14.8; 95% confidence interval: 1.7 to 131.4) had an increased chance of surviving more than 100 days. CLINICAL SIGNIFICANCE: Bone metastases in dogs with solid cancers are associated with poor prognosis and a high risk of skeletal-related events. Treatment appears to have an impact on survival.


Subject(s)
Bone Neoplasms , Dog Diseases , Dogs , Animals , Retrospective Studies , Bone Neoplasms/veterinary , Prognosis , Dog Diseases/pathology
3.
Ann Ig ; 33(1): 67-85, 2021.
Article in English | MEDLINE | ID: mdl-33354697

ABSTRACT

CONTEXT: Sedentary lifestyle is spreading among children living in urban settings. Recent studies in urban health investigated the effects of built environment on children's physical activity, focusing on the concept of "walkability", an index of how much an area is conducive to walking and active transportation. We decided to browse the literature in order to review all possible tools and methods by which walkability has been evaluated and measured. METHODS: We conducted a qualitative review of the literature in agreement with PRISMA guidelines, searching three medical databases for papers published between January 1994 and July 2017. Inclusion criteria were: primary studies, population ≤18 years and exposure variable as an assessment of walkability or built environment. RESULTS: We retrieved 1,702 articles and included 195 of them in the final review. Most of the studies were cross-sectional (n=188, 96.4%). We identified two possible approaches and four main tools to address walkability measurement. A subjective method approach was used in 71 studies (36.4%), an objective method in 87 (44.6%). Only 37 studies (19.0%) used both. Main tools were survey (n=70, 35.9%), Geographic Information System (GIS) (n=64, 32.8%), street audits (n=11, 5.6%) and Walk-score™ (n=3, 1.5%). Forty-six studies (23.4%) used mixed methods. Environmental variables' assessment and definition was found to vary greatly by method of choice. CONCLUSIONS: We found a high degree of heterogeneity regarding methods and measurements of walkability. A standard approach regarding tools and environmental variables' choice and definition will be advisable in order to allow comparisons among studies. Also, more longitudinal studies are needed.


Subject(s)
Environment Design , Residence Characteristics , Built Environment , Child , Cross-Sectional Studies , Humans , Walking
4.
Ann Ig ; 33(1): 100-102, 2021.
Article in English | MEDLINE | ID: mdl-33354699

ABSTRACT

Operating room (OR) efficiency is a hot topic in OR management studies. Benefits of OR efficiency maximization include financial savings, improved patient safety, greater satisfaction for patients and health workers, and increased productivity. However, how to measure the efficiency of an OR suite still remains a pending question. Many performance indicators have been developed (1) and one of the most frequent approaches consists of choosing a set of indicators to create a dashboard for the monitoring of surgical activities. Macario proposed a scoring system based on eight performance indicators (2). A similar approach was used in The Canadian Paediatric Surgical Wait Times Project (3). Although the use of dashboards and scoring systems allows for a wide and in-depth understanding of the numerous factors that contribute to efficiency, it may also raise problems. The use of multiple indicators involves gathering large amounts of data that are not routinely available in every context and are subject to different interpretations if metrics show divergent trends. Moreover, it is not possible to properly establish relative weights among metrics. We propose a different approach, based on a single and overall indicator that can be used as a proxy for OR efficiency. We considered four elements as a minimum set for composing our indicator: raw utilization (RU), turn-over time (TT), preparation time (PT) and case cancellation (CC) (4). RU formed the basis for our considerations, as it is one of the most common and widespread performance indicators. RU represents the percent of time that patients spend in OR during resource hours.


Subject(s)
Efficiency, Organizational , Operating Rooms , Canada , Child , Humans
5.
Ann Ig ; 32(4): 395-406, 2020.
Article in English | MEDLINE | ID: mdl-32744298

ABSTRACT

BACKGROUND: Hospitals performing surgery in Italy underwent important transformations in recent years, with decreasing economic resources and higher expected standards of care. Regional authorities acted differently across the country to adapt to the new scenario, generating heterogeneous outcomes. The Rizzoli Orthopedic Institute (ROI) in the Emilia-Romagna region started its reorganization in 2017, after the issue of new regional regulations about surgical activity. Aim of this paper is to describe the actions taken at ROI and discuss their outcomes. STUDY DESIGN: Action-research. METHODS: From 2017 to 2019 an action-research project was developed to introduce organizational changes within ROI and close the existing gaps between regional requirements and actual features of the Institute. Four areas of intervention were identified: surgical scheduling, appropriateness of surgical setting, monitoring and management of the surgical path and accountability. Progress was monitored through the collection of performance indicators and qualitative investigation of the organizational culture. RESULTS: Changes were implemented in all areas of intervention. Key features were the introduction of Operating Room Management (ORM) skills and the establishment of multiprofessional teams to drive the changes. Performance indicators showed a positive trend in the comparison between 2017 and 2018. Improvements were observed in terms of productivity, scheduling, and respect of standard waiting time, while case-mix did not significantly change. CONCLUSIONS: Effective ORM and collaborative practices can successfully drive the change towards a more efficient surgical process without increasing resources consumption.


Subject(s)
Health Care Reform , Orthopedic Procedures/methods , Orthopedics/organization & administration , Adult , Aged , Appointments and Schedules , Efficiency, Organizational , Female , Health Services Research , Hospitals , Humans , Italy , Male , Middle Aged , Operating Rooms/organization & administration , Orthopedic Procedures/standards , Orthopedics/standards , Patient Care Team/organization & administration , Waiting Lists , Young Adult
6.
Eur J Histochem ; 49(1): 53-8, 2005.
Article in English | MEDLINE | ID: mdl-15823795

ABSTRACT

A novel application of fluorescence in situ hybridization (FISH) to isolated nuclei is described. The method detects gene amplification and chromosome aneuploidy in extracted nuclei from paraffin-embedded tissue of human cancer with greater sensitivity and specificity than existing FISH methods. In this study, the method is applied to signal detection of the HER-2/neu (c-erbB-2) gene, whose amplification is one of the most common genetic alterations associated with human breast cancer. Nuclei were extracted and isolated from formalin fixed, paraffin embedded tissue of 43 different carcinomas (breast, ovary, endometrium, gastrointestinal stromal tumor and malignant mesothelioma). FISH was performed both on sections and extracted nuclei of each tissue using chromosome enumeration probes (CEP) for the centromeric regions of chromosomes 8 and 17, and a locus specific identifier (LSI) for the HER-2/neu oncogene. Differences between ploidy calculated in sections and extracted nuclei were seen in 3 breast carcinomas and 1 gastrointestinal stromal tumor (GIST). Furthermore, 1 breast cancer, previously considered to be borderline for HER-2/neu gene amplification turned out to be clearly amplified. Nuclei extraction and isolation bypass all the problems related to signal interpretation in tissue sections, and the adoption of this new technique, which improves the signal quality in several neoplastic samples, is suggested.


Subject(s)
Aneuploidy , Carcinoma/genetics , Cell Nucleus/genetics , Gene Amplification/genetics , In Situ Hybridization, Fluorescence/methods , Neoplasms/genetics , Paraffin Embedding , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Carcinoma/pathology , Cell Nucleus/pathology , Endometrial Neoplasms/genetics , Endometrial Neoplasms/pathology , Female , Gastrointestinal Neoplasms/genetics , Gastrointestinal Neoplasms/pathology , Genes, erbB-2/genetics , Humans , Mesothelioma/genetics , Mesothelioma/pathology , Neoplasms/pathology , Ovarian Neoplasms/genetics , Ovarian Neoplasms/pathology , Retrospective Studies , Sensitivity and Specificity , Tissue Fixation/methods
7.
Eur J Histochem ; 48(3): 329-34, 2004.
Article in English | MEDLINE | ID: mdl-15590423

ABSTRACT

Qualitative evaluation of protein content in formalin fixed, paraffin-embedded tissues is usually performed by means of cytofluorimetric analysis. On the other hand, several studies underline the opportunity to measure the concentration of nuclear proteins, which is often accomplished by using complex techniques and instrumentation. In the present work, we suggest a new application for the spectrophotometric evaluation of protein content on extracted and isolated nuclei, based on EDTA treatment of specimens and chemical extraction of proteins, followed by direct spectrophotometric measurement at UV wavelengths. We also demonstrate how this parameter correlates with other diagnostic factors, such as the proliferation index (MIB-1) and the DNA content (ploidy) of cells. This method is simple and effective, yet less expensive than other protein quantitation protocols.


Subject(s)
Breast Neoplasms/chemistry , Nuclear Proteins/analysis , Spectrophotometry/methods , Breast Neoplasms/pathology , Cell Nucleus/chemistry , Cell Nucleus/pathology , DNA, Neoplasm/analysis , DNA, Neoplasm/isolation & purification , Female , Fixatives/chemistry , Flow Cytometry , Formaldehyde/chemistry , Humans , Immunohistochemistry , Ki-67 Antigen/analysis , Nuclear Proteins/chemistry , Nuclear Proteins/isolation & purification , Paraffin Embedding , Ploidies , Tissue Fixation
8.
Dig Liver Dis ; 36 Suppl 1: S26-30, 2004 Feb.
Article in English | MEDLINE | ID: mdl-15077908

ABSTRACT

Endocrine tumours of gut and pancreas tract are rare entities originating from cells of the diffuse endocrine system. The endocrine phenotype is assessed by the expression of general and specific endocrine markers. General endocrine markers associate to organelles like large dense core vesicles (e.g. chromogranin A) and small synaptic-like vesicles (e.g. synaptophysin), or to the cytosol, like neuron specific enolase and protein gene product 9.5 (PGP9.5). The specific markers correspond to the hormones produced by tumour cells. Two major categories of endocrine tumours are identified as (i) well-differentiated and (ii) poorly differentiated neoplasms. Well-differentiated tumours/carcinomas (also known as carcinoids) express all general markers of endocrine differentiation and various hormones. Poorly differentiated endocrine carcinomas lack large dense core vesicles markers (chromogranin A), while widely express synaptophysin and cytosol endocrine markers. The clinical behaviour of endocrine tumours spans from benign to low-grade malignant for well-differentiated tumours/carcinomas to high grade malignant for poorly differentiated carcinomas. The Multiple Endocrine Neoplasia type 1 syndrome (MEN1) gene is involved in the genesis of a proportion of both well- and poorly differentiated sporadic tumours. p53 gene abnormality appears as restricted to poorly differentiated endocrine carcinomas.


Subject(s)
Endocrine Gland Neoplasms , Gastrointestinal Neoplasms , Biomarkers, Tumor/analysis , Endocrine Gland Neoplasms/classification , Endocrine Gland Neoplasms/genetics , Gastrointestinal Neoplasms/classification , Gastrointestinal Neoplasms/genetics , Humans , Phenotype
9.
Ann Ital Chir ; 75(6): 691-5, 2004.
Article in Italian | MEDLINE | ID: mdl-15960366

ABSTRACT

The authors describe a case of acute appendicitis associated "serrated" adenoma (SA). to the histological finding of a SA is a colorectal pre-cancerous lesion which presents the morphological and architectural characteristics of hyperplasic polyps, combined with aspects of adenomatous dysplasia. SA can eventually evolve into a malignant cancer, similarly to classic adenomatous polyps. Clinical and pathological aspects of this lesion are hereby analysed, with respect to recent Literature data.


Subject(s)
Adenoma/complications , Appendicitis/complications , Colorectal Neoplasms/complications , Acute Disease , Adenoma/genetics , Adenoma/pathology , Adult , Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Humans , Male
10.
Pathologica ; 94(6): 325-30, 2002 Dec.
Article in Italian | MEDLINE | ID: mdl-12540999

ABSTRACT

Detection of atypical megakaryocytes in bone marrow biopsies, especially in cases of myelodysplastic syndromes (MDS), chronic myeloproliferative disorders (CMPD) and acute leukemias, is facilitated by staining for markers such as Ulex europaeus agglutinin (UEA)-J, CD31, CD61 and von Willebrand factor (VWF), the latter being considered the most sensitive. Recently, LAT (linker for activation of T cells), a molecule involved in T-cell activation and platelet aggregation, was found to be expressed by megakaryocytes and platelets in tissue sections. We compared VWF and LAT immunoreactivity on megakaryocytes in 64 bone marrow biopsies from 12 normal controls (NC), and from patients with MDS (n=18), CMPD (n=21) and acute megakaryocytic leukemia (AML-M7, n=13). Immunostaining was performed on paraffin sections with polyclonal antibodies against VWF and LAT. Immunoreactivity was evaluated by counting positive megakaryocytes in 10 high-power fields, and values were compared using Student's t test for paired data. Both VWF and LAT predominantly stained the cytoplasm of megakaryocytes, although LAT was also recognizable on the cell membrane. In most biopsies, the immunoreactivity of the two antibodies was quite similar. No significant differences were noticed between the mean values of VWF+ and LAT+ megakaryocytes. However, in 22 cases (5 NC; 5 MDS; 6 CMPD; 6 AML-M7), the number of LAT+ megakaryocytes was at least 30% higher than VWF+cells, while in 3 cases opposite findings were found. In 3 AML-M7 cases, anti-LAT antibodies stained numerous megakaryocytes, but anti-VWF staining was practically negative; in another 5 AML-M7 cases, anti-LAT labeling was much stronger than anti-VWF staining. LAT represents a useful immunohistochemical marker for megakaryocytes in normal and pathological conditions. It seems to be expressed by megakaryocytes more than VWF in most cases and, particularly, in conditions associated with poorly differentiated megakaryocytes, such as acute megakaryocytic leukemias. The use of LAT staining should be recommended in association with other megakaryocyte markers in the study of bone marrow biopsies in cases of hematopoietic disorders.


Subject(s)
Adaptor Proteins, Signal Transducing , Biopsy , Bone Marrow/pathology , Carrier Proteins/analysis , Megakaryocytes/chemistry , Membrane Proteins , Phosphoproteins/analysis , Biomarkers , Biomarkers, Tumor/analysis , Cytoplasm/chemistry , Factor VIII/analysis , Female , Humans , Immunoenzyme Techniques , Leukemia, Megakaryoblastic, Acute/metabolism , Leukemia, Megakaryoblastic, Acute/pathology , Lymphoma/chemistry , Lymphoma/pathology , Male , Myelodysplastic Syndromes/metabolism , Myelodysplastic Syndromes/pathology , Myeloproliferative Disorders/metabolism , Myeloproliferative Disorders/pathology , Paraffin Embedding , von Willebrand Factor/analysis
11.
Virchows Arch ; 439(6): 776-81, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11787850

ABSTRACT

The genetic study of two cases of tubulovillous adenoma associated with poorly differentiated endocrine carcinoma (PDEC) is reported. Aim of this work was to assess whether the exocrine and endocrine growths share a common genotype. The analysis entailed the search for allelic loss (LOH) or imbalances of polymorphic microsatellite markers at the corresponding chromosomal loci of the genes MEN-1 (11q13), p53 (17p13). Deleted in Colorectal Carcinoma (DCC) (18q21) and hMSH-2 (BAT26) (2p21-22). Additionally, the exons 5-8 of the p53 gene were sequenced in the two PDECs only. One of the two cases investigated showed LOH for 18q DCC markers in the tubulo-villous adenoma while a point mutation of the p53 gene was observed in the PDEC component. No genetic abnormality was observed in both adenoma and PDEC components of the other case. In the two cases p53 protein accumulation was observed in both PDEC and adenoma cells. These data indicate that only the p53 gene abnormality is shared by both colon cancer and PDEC in the two cases reported. The lack of other common genetic defect may suggest a different histogenesis for the two tumor types. The development of colon PDEC implies the defect of p53 gene.


Subject(s)
Adenoma, Villous/genetics , Carcinoma, Neuroendocrine/genetics , Colonic Neoplasms/genetics , DNA-Binding Proteins , Adenoma, Villous/chemistry , Adenoma, Villous/pathology , Adenoma, Villous/surgery , Aged , Carcinoma, Neuroendocrine/chemistry , Carcinoma, Neuroendocrine/secondary , Carcinoma, Neuroendocrine/surgery , Colonic Neoplasms/chemistry , Colonic Neoplasms/pathology , Colonic Neoplasms/surgery , DNA, Neoplasm/analysis , Female , Genes, DCC/genetics , Genes, p53/genetics , Humans , Immunoenzyme Techniques , Loss of Heterozygosity , Male , Microsatellite Repeats , Middle Aged , MutS Homolog 2 Protein , Neoplasms, Multiple Primary , Polymerase Chain Reaction , Proto-Oncogene Proteins/genetics , Sequence Analysis, DNA
12.
Expert Rev Mol Diagn ; 1(3): 323-33, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11901838

ABSTRACT

Although relatively rare, endocrine tumors of the digestive tract and pancreas have been widely investigated and represent a complex tumor entity. The two major categories of well-differentiated and poorly differentiated tumors show important phenotypic and clinical differences. In well-differentiated tumors the multiple endocrine neoplasia syndrome of Type 1 (MEN1) gene is frequently abnormal, though a complex multiple gene involvement is postulated for different tumor types. Poorly differentiated carcinomas show frequent p53 gene hyperexpression/defects, characterizing severe cell abnormality and possibly accounting for the malignancy of such carcinomas.


Subject(s)
Intestinal Neoplasms/genetics , Pancreatic Neoplasms/genetics , Proto-Oncogene Proteins , Stomach Neoplasms/genetics , Cell Differentiation , Genes, p53/genetics , Humans , Intestinal Neoplasms/diagnosis , Mutation , Neoplasm Proteins/genetics , Pancreas/pathology , Pancreatic Neoplasms/diagnosis , Stomach Neoplasms/diagnosis
13.
Digestion ; 62 Suppl 1: 19-26, 2000.
Article in English | MEDLINE | ID: mdl-10940683

ABSTRACT

Neuroendocrine tumors of the digestive tract are rare entities characterized by significant phenotype differences and traditionally considered to originate from cells of the diffuse endocrine system of the pancreas and gut. Two major categories with significant phenotype and clinical behavior differences are identified as well-differentiated and poorly differentiated tumors. Investigation on the molecular basis of tumor development points to an important role for the multiple endocrine neoplasia syndrome type-1 (MEN1) gene because of its frequent abnormality observed both in well-differentiated and poorly differentiated tumors. Other genes are possibly involved, though the available data need support from studies on larger series of tumors.


Subject(s)
Gastrointestinal Neoplasms/genetics , Gastrointestinal Neoplasms/pathology , Neuroendocrine Tumors/genetics , Neuroendocrine Tumors/pathology , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/pathology , Animals , Biomarkers, Tumor/analysis , Cell Transformation, Neoplastic/genetics , Cell Transformation, Neoplastic/pathology , Genotype , Humans , Immunohistochemistry/methods , Phenotype
14.
J Lab Clin Med ; 113(5): 549-60, 1989 May.
Article in English | MEDLINE | ID: mdl-2541212

ABSTRACT

Previous studies have shown that platelet-activating factor (PAF) receptor blocking has a protective effect on rabbit nephrotoxic nephritis (NTN). We examined whether arachidonic acid (AA) metabolism is altered in NTN and whether a PAF receptor antagonist has any influence on such changes. Rabbits injected with anti-glomerular basement membrane antiserum in the heterologous phase had a markedly increased glomerular thromboxane B2 (TxB2) production level, whereas no changes have been detected in glomerular 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and prostaglandin E2 (PGE2). During the autologous phase of the disease, the glomerular TxB2 level was even higher than in the heterologous phase. The level of 6-keto-PGF1 alpha was significantly lower than normal, and the level of PGE2 was unchanged in respect to the basal values. The use of L-652,731 (a specific PAF receptor antagonist) reversed the abnormal generation of AA metabolites at glomerular level both in the heterologous and autologous phase of the disease. The effect of L-652,731 on AA metabolism is likely to be an indirect result of the PAF receptor blocking, because L-652,731 given to normal rabbits had no direct effect on glomerular AA metabolism. To assess whether the beneficial effect of L-652,731 in NTN is at least in part mediated by its capability of suppressing the excessive intrarenal synthesis of thromboxane A2 (TxA2), we compared the effect of L-652,731 with that of a selective TxA2-synthase inhibitor (FCE-22178). FCE-22178 ameliorated the morphologic expression of rabbit NTN and reduced function deterioration. The protective effect of L-652,731 on proteinuria in the autologous phase and on glomerular filtration rate in both phases was superior to that of FCE-22178. We conclude that an excessive intraglomerular synthesis of TxA2 occurs in rabbit NTN that can play a role in renal function deterioration. Both a specific PAF receptor antagonist and a TxA2-synthase inhibitor reduced the exaggerated TxA2 synthesis and favorably influenced the evolution of the disease.


Subject(s)
Glomerulonephritis/drug therapy , Kidney Glomerulus/metabolism , Platelet Activating Factor/physiology , Platelet Membrane Glycoproteins , Receptors, Cell Surface/drug effects , Receptors, G-Protein-Coupled , Thromboxane A2/physiology , Animals , Arachidonic Acid , Arachidonic Acids/metabolism , Furans/pharmacology , Glomerulonephritis/etiology , Kidney/drug effects , Kidney/pathology , Kidney/physiopathology , Male , Platelet Activating Factor/antagonists & inhibitors , Platelet Aggregation/drug effects , Prostaglandins/biosynthesis , Rabbits , Thromboxane-A Synthase/antagonists & inhibitors
15.
Am J Physiol ; 254(6 Pt 2): H1218-23, 1988 Jun.
Article in English | MEDLINE | ID: mdl-2837916

ABSTRACT

To determine whether platelet-activating factor (PAF) has a physiological role in the process of primary hemostasis in the rabbit, we measured skin bleeding times in animals given orally a specific PAF-receptor antagonist L-652,731. One hour after the administration of L-652,731 (20 or 40 mg/kg), a significant prolongation of bleeding time was observed. Parameters known to interfere with the process of primary hemostasis were not altered by PAF-receptor antagonist. In addition, no changes were observed in platelet count and vessel wall arachidonic acid metabolism, as revealed by serum thromboxane B2 levels, vascular 6-ketoprostaglandin F1 alpha generation, and by aspirin experiment. The fact that aspirin alone did not induce prolongation of bleeding time in rabbits is probably due to the simultaneous inhibition of platelet thromboxane A2 and vascular prostacyclin. [3H]PAF binding to washed platelets of rabbits given L-652,731 showed a significant reduction in maximum number of detectable binding sites in comparison with values found in the same animals before the L-652,731 administration. The results suggest that the bleeding-time prolongation observed after L-652,731 administration results from its ability to selectively inhibit PAF bioactivity. Thus locally released PAF appears to exert a physiological role in the process of platelet plug formation that follows a skin incision in the rabbit.


Subject(s)
Furans/pharmacology , Hemostasis/drug effects , Platelet Activating Factor/antagonists & inhibitors , Platelet Membrane Glycoproteins , Receptors, G-Protein-Coupled , Animals , Hematocrit , Kinetics , Male , Platelet Activating Factor/metabolism , Platelet Activating Factor/physiology , Platelet Aggregation , Platelet Count , Prostaglandins/biosynthesis , Prostaglandins/blood , Rabbits , Receptors, Cell Surface/metabolism
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