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1.
Clin Radiol ; 69(1): 59-62, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24156793

RESUMO

AIMS: To assess accuracy of multidetector computed tomography (MDCT) and individual radiological signs in the diagnosis of anastomotic leaks. MATERIALS AND METHODS: Patients undergoing anterior resection with a stapled anastomosis over a 2 year period were identified. Electronic and clinical records of these patients were reviewed. Unenhanced and/or enhanced MDCT was performed with intravenous and/or per-rectal contrast medium and read by a radiologist blinded to the patients' clinical details to determine the sensitivity and specificity of specific findings at MDCT for identifying leaks. RESULTS: Seventeen percent (30/170) of the anterior resections were suspected to have an anastomotic leak. Ninety-three percent (28/30) of patients underwent MDCT. Seven point six percent (11+2/170) had a confirmed leak. Two patients underwent surgery without MDCT. A leak was confirmed by MDCT in 91% (10/11) of patients. The sensitivity, specificity, and positive and negative predictive values of MDCT in diagnosing a leak was 0.91, 1, 1, and 0.95, respectively. The sensitivity of peri-anastomotic air, peri-anastomotic collection, extravasation of rectal contrast medium, and staple line integrity was 0.81, 0.63, 0.54, and 0.72, respectively. Use of rectal contrast medium (8/11 cases) increased the subjective ease of diagnosis and was the only sign in one patient. CONCLUSIONS: Presence of peri-anastomotic air is a reliable marker of anastomotic leaks at MDCT. Leakage of rectal contrast medium is highly accurate and increases confidence of diagnosis. The appearance of the staple line itself is not accurate in assessing anastomotic integrity.


Assuntos
Fístula Anastomótica/diagnóstico por imagem , Doenças do Colo/cirurgia , Tomografia Computadorizada por Raios X/métodos , Anastomose Cirúrgica , Meios de Contraste , Diatrizoato de Meglumina , Feminino , Humanos , Masculino , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Grampeamento Cirúrgico
2.
J Appl Microbiol ; 114(1): 1-10, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22897125

RESUMO

Antimicrobial resistance continues to be an inexorable threat for the biomedical and biochemical researchers. Despite the novel discoveries in drug designing and delivery, high-throughput screening and surveillance data render the prospects for new antimicrobial agents as bleak as ever. The advent of nanotechnology, however, strengthens pharmacology by offering effective therapeutics to treat this aforementioned problem. Several nanoparticles of the known elements have already been reported for their antimicrobial efficacy. Nanosized fabrication of elemental sulphur with suitable surface modifications offers to retrieve the use of sulphur (man's oldest known ecofriendly microbicide) as a potential antimicrobial agent. Sulphur nanoparticles (SNPs) are effective against both conventionally sulphur-resistant and sulphur-susceptible microbes (fungi and bacteria). Moreover, biocompatible polymers present on the surface of SNPs minimize toxicity during application. Here, we focus on various aspects of physicochemical features of SNPs and their biochemical interactions with microbes. The present review also illustrates the effects of SNPs on plants and animals in terms of cytotoxicity and biocompatibility.


Assuntos
Anti-Infecciosos/química , Nanopartículas/química , Enxofre/química , Anti-Infecciosos/efeitos adversos , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Fungos/efeitos dos fármacos , Células Hep G2 , Humanos , Nanopartículas/efeitos adversos , Plantas/efeitos dos fármacos , Enxofre/efeitos adversos , Enxofre/farmacologia
4.
Diabet Med ; 27(3): 266-73, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20536488

RESUMO

AIMS: To study the variation in daytime glucose tolerance and pancreatic B-cell function at different levels of glycated haemoglobin (HbA(1c)) in subjects with Type 2 diabetes (T2DM). METHODS: T2DM subjects (n = 49; 34 men) had 12-h daytime plasma glucose (PG), insulin (PI), total (PTp) and intact proinsulin (PIp) profiles determined in response to three identical test meals at 4-h intervals. Subjects were divided into three groups according to HbA(1c)--group 1: < 7.3% (n = 18); group 2: 7.3-8.0% (n = 17); group 3: > 8.0% (n = 14). Fasting and preprandial (prior to meals 2 and 3) concentrations, total area under the curve (AUC), AUC above fasting (dAUC) and maximum postprandial metabolic concentrations (C(max)) were compared between the three meals and across the groups. RESULTS: Subjects in group 1 had significantly higher fasting plasma glucose (FPG) compared with preprandial PG concentrations (7.1 +/- 0.2 vs. 5.9 +/- 0.3 vs. 5.4 +/- 0.2; P < 0.01). Subjects in groups 2 and 3 had significantly higher FPG compared with preprandial PG levels prior to meal 3. PG.dAUC was highest in response to meal 1 and lowest following meal 2 (P < 0.05). FPI concentrations were significantly lower compared with preprandial PI concentrations. Subjects in group 1 had significantly higher PI prior to meal 2 compared with meal 3. PI.dAUC was highest in response to meal 1. Subjects in group 1 had lowest PI.dAUC following meal 2. FTp and FIp concentrations were also significantly lower compared with preprandial concentrations. PTp.dAUC and PIp.dAUC was highest in response to meal 1. CONCLUSIONS: There appears to be a shift in diurnal variation in glucose homeostasis and pancreatic B-cell function. Subjects had decreased glucose tolerance in response to the first and third meal of the day irrespective of glycaemic control. The variability in glucose tolerance was reflected by both quantitative and qualitative dysfunction of the pancreatic B-cell.


Assuntos
Glicemia/metabolismo , Ritmo Circadiano , Diabetes Mellitus Tipo 2/fisiopatologia , Células Secretoras de Insulina/metabolismo , Período Pós-Prandial/fisiologia , Área Sob a Curva , Diabetes Mellitus Tipo 2/sangue , Jejum , Feminino , Teste de Tolerância a Glucose , Hemoglobinas Glicadas/análise , Humanos , Insulina/metabolismo , Secreção de Insulina , Masculino , Pessoa de Meia-Idade , Proinsulina/metabolismo
5.
Eur Radiol ; 20(3): 621-9, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19727743

RESUMO

AIM: To assess accuracy of CT colonography (CTC) in identifying synchronous lesions in patients with colorectal carcinoma. METHODS: This study included 174 consecutive patients undergoing CTC as part of staging or primary investigation where a colorectal cancer was diagnosed between 2004 and 2007. Prone unenhanced and portal phase enhanced supine series with air or CO(2) distension were acquired using 4- or 16-slice CT (Toshiba) and read by 2D +/- 3D formats. Synchronous lesions were classified according to American College of Radiology's (ACR) polyp classification. Segmental gold standard was flexible sigmoidoscopy/colonoscopy within 1 year and/or histology of colonic resection supplemented by follow-up. Nine patients without gold standard were excluded. Sensitivity, specificity and accuracy were calculated on a per polyp, per patient and per segment basis and discrepancies analysed. RESULTS: Direct comparable data were available for 764/990 colonic segments from 165 patients. Of 41 (C2-C4) synchronous lesions on "gold standard", 33 were correctly identified on virtual colonoscopy (VC), overall per polyp sensitivity was 80.5%, with detection rates of 20/24 C3 (83.3%) and 3/3 C4 (100%) with per patient and per segment specificity of 95.4% and 99.2%, respectively. CONCLUSION: CTC is an accurate technique to assess for significant synchronous lesions in patients with colorectal cancer and is applicable for total pre-operative colonic visualisation.


Assuntos
Pólipos do Colo/diagnóstico por imagem , Colonografia Tomográfica Computadorizada/métodos , Neoplasias Colorretais/complicações , Neoplasias Colorretais/diagnóstico por imagem , Adulto , Idoso , Pólipos do Colo/complicações , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
7.
Dig Surg ; 24(5): 358-60, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17785980

RESUMO

INTRODUCTION: Percutaneous radiofrequency ablation (PcRFA) provides alternative means of treating patients with unresectable colorectal liver metastases. We previously reported our initial experience in 30 patients treated with PcRFA. We present the final long-term results in these 30 patients. METHODS: The final outcome of the 30 patients treated with PcRFA is reported, 30 months following the initial results published in 2004. RESULTS: Thirty patients (21 males and 9 females), median age 74.5 (44-85) years, underwent PcRFA for 57 lesions in 60 sessions. The final results in this cohort of patients are reported: 28 dead and 2 lost to follow-up. Median follow-up was 22 (3-53) months. Median size was 31 (8-70) mm. Nineteen lesions required repeat PcRFA. Median ablation time per lesion was 12 (4.5-36) min. Eleven patients received chemotherapy pre-PcRFA and 15 received chemotherapy post-PcRFA. Three patients went on to have limited hepatectomies. Complications occurred in 3 (5%) and median hospital stay was 1 (1-7) day. The median hepatic disease-free survival was 12 (95% CI 6.1-17.9) months and actuarial survival was 23.2 (95% CI 18.5-27.8) months. CONCLUSION: PcRFA is safe and associated with increased disease-free and overall survival in patients with unresectable colorectal hepatic metastases.


Assuntos
Ablação por Cateter/métodos , Neoplasias Colorretais , Neoplasias Hepáticas/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Ablação por Cateter/mortalidade , Intervalo Livre de Doença , Feminino , Seguimentos , Humanos , Estimativa de Kaplan-Meier , Neoplasias Hepáticas/secundário , Neoplasias Hepáticas/cirurgia , Masculino , Pessoa de Meia-Idade , Taxa de Sobrevida , Fatores de Tempo , Resultado do Tratamento
8.
Eur J Vasc Endovasc Surg ; 34(6): 699-701, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17689274

RESUMO

We report a 90-year old man who presented with severe lower extremity ischaemia due to spontaneous dissection of a non-aneurysmal infrarenal abdominal aorta. The aortic lesion was treated using an aorto-uni-iliac stent-graft with contralateral common iliac artery occlusion and femoro-femoral cross-over bypass. The patient underwent digital amputation and debridement of the foot four weeks post-operatively. At 12 months follow-up, he remains symptom-free with an excluded dissection, patent reconstruction and healed foot.


Assuntos
Angioplastia , Aneurisma da Aorta Abdominal/cirurgia , Dissecção Aórtica/cirurgia , Isquemia/cirurgia , Perna (Membro)/irrigação sanguínea , Idoso de 80 Anos ou mais , Amputação Cirúrgica , Dissecção Aórtica/diagnóstico , Aneurisma da Aorta Abdominal/diagnóstico , Aortografia , Artéria Femoral/cirurgia , Seguimentos , Gangrena , Humanos , Artéria Ilíaca/cirurgia , Isquemia/diagnóstico , Masculino , Complicações Pós-Operatórias/diagnóstico , Complicações Pós-Operatórias/cirurgia , Reoperação , Dedos do Pé/irrigação sanguínea , Tomografia Computadorizada por Raios X
9.
Eur J Pediatr Surg ; 15(2): 102-6, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15877258

RESUMO

The colonic pouch excised during surgery in 17 patients with congenital pouch colon associated with anorectal agenesis (CPC) was subjected to detailed histological examination after staining with hematoxylin and eosin. The patients included 11 newborns, 3 infants, and 3 older children. The most frequently observed abnormalities were acute and chronic inflammation of the mucosa and submucosa, focal or generalized thinning of muscle layers, especially of the outer muscle coat, disorganized muscle layers, a decreased number of mature ganglion cells, and neuronal hyperplasia and hypertrophy in nerve plexuses. Ectopic heteroplastic tissues were identified in 2 patients. These findings suggest that the colonic pouch in CPC represents abnormally developed colonic tissue and points to the similarity with segmental dilatation of the colon. The neuromuscular abnormalities explain the physiological characteristics of the colonic pouch, namely weak peristalsis as well as the propensity to undergo marked dilatation even after tubularization.


Assuntos
Colo/patologia , Anormalidades do Sistema Digestório/patologia , Reto/patologia , Pré-Escolar , Colectomia , Colo/anormalidades , Anormalidades do Sistema Digestório/cirurgia , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Reto/anormalidades
10.
Dig Surg ; 21(4): 314-20, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15365230

RESUMO

BACKGROUND AND AIM: Most patients with hepatic metastases from colorectal carcinoma are unsuitable for resection. Radiofrequency ablation (RFA) has been applied to such lesions at laparotomy. This study aimed to evaluate the less invasive approach of percutaneous RFA. METHOD: Patients with unresectable liver metastases identified on cross-sectional imaging were considered for percutaneous RFA either alone or in combination with systemic chemotherapy. Subjects with >6 lesions or lesions of maximum size >70 mm were excluded. Percutaneous RFA was applied under sedation and radiological guidance (CT/US). Treatment effect was determined by follow-up imaging. Actuarial survival was calculated by the Kaplan-Meier analysis. RESULTS: Thirty patients (21 males), median age 74.5 years (range 44-85 years), underwent percutaneous RFA to 56 lesions during 54 treatment sessions. The median size of lesion was 30 mm (range 8-70 mm). Fifteen lesions were treated more than once because of recurrence or incomplete ablation. The median ablation time per lesion was 12 min (range 4.5-36 min). Eleven patients had pre-procedural chemotherapy and 15 patients received chemotherapy after treatment. There was minimal associated morbidity (5.6% of treatments). Median hospital stay per treatment was 1 day (range 1-7). Median actuarial survival from the date of first percutaneous RFA was 22 months (95% CI 12.9-31.1 months). Eleven patients were alive at the time of data collection. CONCLUSION: Percutaneous RFA is a safe, well-tolerated intervention for unresectable hepatic metastases which can be repeated, if required. The technique may be associated with prolonged survival in this selected group of subjects. Future studies should consider the role of percutaneous RFA either in place of or as an adjunct to palliative chemotherapy.


Assuntos
Ablação por Cateter/métodos , Neoplasias Colorretais/patologia , Neoplasias Hepáticas/secundário , Neoplasias Hepáticas/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Neoplasias Hepáticas/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Radiografia Intervencionista , Tomografia Computadorizada por Raios X , Resultado do Tratamento
11.
Clin Radiol ; 59(3): 227-36, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15037134

RESUMO

Morbid obesity is a significant clinical problem in the western world. Various surgical restrictive procedures have been described as an aid to weight reduction when conservative treatments fail. Adjustable laparoscopic gastric banding (LAPBAND) has been popularized as an effective, safe, minimally invasive, yet reversible technique for the treatment of morbid obesity. Radiological input is necessary in the follow-up of these patients and the diagnosis of complications peculiar to this type of surgery. In this review we will highlight the technical aspects of radiological follow-up and the lessons learnt over the last 5 years.


Assuntos
Gastroplastia/efeitos adversos , Gastroplastia/métodos , Laparoscopia/métodos , Obesidade Mórbida/diagnóstico por imagem , Complicações Pós-Operatórias/etiologia , Dilatação Patológica/etiologia , Desenho de Equipamento , Falha de Equipamento , Seguimentos , Gastroplastia/instrumentação , Humanos , Laparoscopia/efeitos adversos , Obesidade Mórbida/cirurgia , Radiografia , Infecção da Ferida Cirúrgica/etiologia , Redução de Peso
12.
Pediatr Surg Int ; 18(5-6): 498-500, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12415391

RESUMO

Necrotizing amebic colitis (NAC) is a rare complication of intestinal amebiasis, and only a few cases have been reported in the literature. The outcome of NAC is dismal, particularly in children. We encountered a 3-year-old child who presented with bloody diarrhea, fever, toxemia, and peritonitis. At laparotomy the whole colon was found to be necrotic with several perforations. Histopathology of the resected colon showed features of NAC. This is a rare case of survival of a child with NAC involving the whole colon.


Assuntos
Disenteria Amebiana/cirurgia , Pré-Escolar , Disenteria Amebiana/diagnóstico , Disenteria Amebiana/patologia , Feminino , Humanos , Necrose
13.
AJR Am J Roentgenol ; 176(1): 161-5, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11133560

RESUMO

OBJECTIVE: Gastroesophageal anastomotic leak after cancer resection has a mortality rate of up to 60% and significant morbidity, whatever the mode of treatment. We assessed the efficacy of esophageal stenting as a therapeutic option to reduce the mortality and morbidity associated with symptomatic intrathoracic anastomotic leakage. SUBJECTS AND METHODS: During a 52-month period, 14 patients had placement of stents for clinically significant postoperative leaks: 10 patients had an esophagogastrectomy and four patients had a total gastrectomy with esophagojejunal anastomosis. Thirteen of 14 patients had tumors that were histologically staged as T3 N1 M0 or worse. Significant anastomotic leaks were revealed by a contrast-enhanced study at 3-28 days after surgery. Stents were inserted in patients in whom the leakage was debilitating or initial conservative treatment had failed. Stenting outcome in terms of clinical and radiologic healing, hospital stay, survival, and complications was assessed. RESULTS: No procedural morbidity or 30-day mortality occurred. Immediate postprocedural leak occlusion was obtained in all patients. Clinical healing of the leak occurred in 13 (92.8%) of 14 patients, with a median healing time of 6 days. Of the 13 patients, healing occurred within 10 days in 10 patients (76.9%). Eight of these 10 early closures received a knitted nitinol stent (p = 0.02). One patient (7%) died as a consequence of leakage at 135 days. Median survival for all 14 patients was 11 months (Kaplan-Meier method). Complications included five episodes of food blockages in three patients, which required endoscopic clearance, and one case of stent-related upper gastrointestinal hemorrhage. No patients developed anastomotic stricture or occlusive epithelial hyperplasia. CONCLUSION: Covered esophageal stenting appears to reduce the mortality and morbidity of symptomatic anastomotic leakage after surgery for gastroesophageal cancer. Knitted nitinol stents may be best suited to this purpose.


Assuntos
Esôfago , Stents , Estômago/cirurgia , Idoso , Idoso de 80 Anos ou mais , Anastomose Cirúrgica/efeitos adversos , Materiais Revestidos Biocompatíveis , Neoplasias Esofágicas/cirurgia , Esôfago/diagnóstico por imagem , Esôfago/cirurgia , Feminino , Fluoroscopia , Humanos , Masculino , Metais , Pessoa de Meia-Idade , Cuidados Paliativos , Radiografia Intervencionista , Stents/efeitos adversos , Estômago/diagnóstico por imagem , Neoplasias Gástricas/cirurgia
14.
J Bone Joint Surg Br ; 81(2): 229-33, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10204926

RESUMO

Acute swelling of the hand is a common problem after trauma or surgery and is associated with both pain and loss of function. We describe a prospective study of 47 patients in which we assessed the effects of a pneumatic compression device (A-V impulse hand pump) on the swollen hand. The pump reduced swelling by increasing the velocity of venous return as demonstrated by Duplex scanning of the median cubital vein. Continuous use of the pump for 48 hours gave a reduction of 78.6% in swelling of the injured hand compared with the opposite, uninjured side. Even when used intermittently, with the pump on for 12 hours out of 24, a statistically significant effect was seen. There was a subjective reduction in pain and an objective improvement in function of the hand. Use of the pump resulted in a nearly normal hand by the time of discharge from hospital after, on average, 48 hours.


Assuntos
Edema/terapia , Traumatismos da Mão/terapia , Pressão , Adolescente , Adulto , Idoso , Velocidade do Fluxo Sanguíneo , Pressão Sanguínea , Edema/fisiopatologia , Feminino , Traumatismos da Mão/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Tempo
16.
Int Urol Nephrol ; 27(2): 141-5, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-7591569

RESUMO

This case report illustrates the importance of performing conservative renal surgery, rather than nephrectomy, in patients with giant echinococcal lesions, even if preliminary peroperative assessment suggests a need to sacrifice the kidney.


Assuntos
Equinococose/cirurgia , Nefropatias/cirurgia , Rim/cirurgia , Adulto , Equinococose/diagnóstico por imagem , Feminino , Humanos , Nefropatias/diagnóstico por imagem , Radiografia
17.
J Urol ; 149(4): 868, 1993 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8455264
18.
Cancer Res ; 49(10): 2761-5, 1989 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-2713859

RESUMO

A 34-kDa growth factor expressed by trophoblasts and certain carcinomas binds to target fibroblastic cells through specific high-affinity receptors. Here we report studies on the cellular routing behavior of the receptor-bound 34-kDa protein. Internalization was visualized by using lissamine rhodamine-conjugated 34-kDa protein and was quantified by analyzing the acid dissociability of cell-bound radioiodinated protein after incubation at 37 degrees C. The protein was found to be rapidly internalized in a temperature-sensitive manner. However, in contrast with other protein ligands, the 34-kDa protein was not rapidly degraded. The extent of ligand degradation was small as quantified by gel filtration analysis. Studies on the receptor showed that there was an atypical up-regulation, i.e., increase in surface receptors in response to ligand binding at 37 degrees C. The up-regulation was partially blocked by cycloheximide, an inhibitor of protein biosynthesis, but not by known inhibitors of receptor recycling such as monensin, chloroquine, and methylamine, suggesting that enhanced receptor biosynthesis may be responsible for the process. These studies indicate that the cellular routing and receptor regulatory characteristics of the internalized 34-kDa growth factor are different from those of most growth factor ligands and imply the involvement of receptor up-regulation in signal transduction.


Assuntos
Endocitose , Substâncias de Crescimento/metabolismo , Trofoblastos/metabolismo , Células Cultivadas , Humanos , Receptores Mitogênicos/metabolismo
19.
Eur J Biochem ; 172(3): 777-83, 1988 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-3350024

RESUMO

Recently we isolated a new protein growth factor of 34 kDa from synctial membranes of human placenta. In its polypeptide molecular mass, antigenic structure, receptor binding specificity and partial amino acid sequence, it is unlike several known growth factors, hormones and other proteins. Here we report studies on its biosynthesis and turnover in cultured cytotrophoblasts from term human placenta. Expression of the 34-kDa protein in these cells was studied by immunoprecipitation and Western blot analyses using a highly specific antibody. The experiments have produced the following results. a) Immunostaining and Western blot analyses have demonstrated the presence of immunoreactive 34-kDa protein in isolated cytotrophoblasts. The protein is present in both freshly isolated cells and in cells that have fused in culture to form multinuclear syncytiotrophoblasts. b) Trophoblastic biosynthesis of the protein has been demonstrated by in vitro translation of cellular mRNA and by metabolic labelling experiments with intact cells. c) Pulse-chase experiments show that biosynthesis of the protein does not involve any detectable precursors of higher or lower molecular mass. d) Studies on turnover indicate that the synthesized protein is unusually stable with a half-life of 50-70 h.


Assuntos
Substâncias de Crescimento/metabolismo , Proteínas/metabolismo , Trofoblastos/metabolismo , Células Cultivadas , Feminino , Humanos , Técnicas In Vitro , Placenta/metabolismo , Gravidez , Biossíntese de Proteínas , RNA Mensageiro/metabolismo
20.
Proc Natl Acad Sci U S A ; 85(6): 2014-8, 1988 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-3162324

RESUMO

Recently we isolated a protein growth factor of 34 kDa from trophoblastic membranes of human placenta. A fraction (approximately equal to 50%) of the membrane-associated 34-kDa protein is peripherally associated--i.e., it can be released by high salt treatment. The remainder shows the characteristics of an integral membrane protein--i.e., its release requires detergent treatment. Here we report studies on the structural basis for membrane anchorage of the protein. Phospholipase C was found to release an immunoreactive 34-kDa polypeptide from intact isolated cytotrophoblasts. Studies with isolated trophoblastic membranes showed that phospholipase C specifically released the salt-resistant fraction of the 34-kDa polypeptide. The polypeptide released by phospholipase C showed the same electrophoretic mobility in NaDodSO4/PAGE as the polypeptide prior to phospholipase C treatment. The identity of the released protein with the 34-kDa growth factor has been established by both immunologic and receptor-binding assays. Other studies show that there is biosynthetic incorporation of [3H]myristate into the 34-kDa protein. The myristate label is labile to phospholipase C treatment. These results suggest that some of the 34-kDa protein is anchored to the plasma membrane via a posttranslationally added phospholipid. This mode of anchorage has been observed for some other membrane proteins and raises interesting questions regarding the role of this novel linkage in the mitogenic function of the 34-kDa polypeptide.


Assuntos
Substâncias de Crescimento/análise , Fosfolipídeos/análise , Trofoblastos/análise , Acilação , Animais , Feminino , Humanos , Peso Molecular , Ácido Mirístico , Ácidos Mirísticos/metabolismo , Gravidez , Primeiro Trimestre da Gravidez , Coelhos , Fosfolipases Tipo C/metabolismo
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