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1.
Transplant Proc ; 43(7): 2669-77, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21911144

RESUMO

BACKGROUND: Since implementation of the Model for End-stage Liver Disease (MELD), the number of simultaneous liver-kidney transplantations (SLKT) has increased in the United States. However, predictors and survival benefit of SLKT compared to liver transplantation alone (LTA) are not well defined. METHODS: Organ Procurement and Transplantation Network data of patients with end-stage liver disease (ESLD) with estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m(2) who had not been on dialysis while on the waiting list and underwent liver transplantation between 2002 and 2008 were analyzed. To identify predictors of undergoing SLKT versus LTA, multiple logistic regression analysis was performed. Cox proportional hazards regression analysis was used to assess the association between SLKT and post-liver transplant patient and graft survival. RESULTS: The study cohort comprised 5443 patients; 262 (5%) underwent SLKT and 5181 (95%) underwent LTA. Adjusting for potential confounders, patients who underwent SLKT were 34% less likely to die after liver transplantation than those who underwent LTA (hazard ratio [HR] = 0.66, P = .012) and 33% less likely to have liver graft failure than those who underwent LTA (HR = 0.67, P = .010). Among those who underwent SLKT, 1-, 3-, and 5-year kidney graft survival probabilities were 88%, 80%, and 77%, respectively. Black race and diabetes were associated with a higher likelihood of SLKT versus LTA; female sex, a higher eGFR, and higher MELD score reduced the likelihood of SLKT. CONCLUSIONS: Among those with ESLD and kidney dysfunction not on dialysis, post-liver transplant patient and liver graft survivals of patients who underwent SLKT were superior to those of patients who underwent LTA. Whether this reflects differences in the two groups that could not be adjusted in survival models or a specific effect of kidney dysfunction cannot be established.


Assuntos
Doença Hepática Terminal/cirurgia , Transplante de Rim , Transplante de Fígado , Estudos de Coortes , Feminino , Sobrevivência de Enxerto , Humanos , Funções Verossimilhança , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Taxa de Sobrevida , Listas de Espera
5.
Am J Physiol Gastrointest Liver Physiol ; 281(4): G1051-8, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11557526

RESUMO

Cross talk between signal transduction pathways augments pepsinogen secretion from gastric chief cells. A-kinase anchoring proteins (AKAPs) associate with regulatory subunits of protein kinase A (PKA), protein kinase C (PKC), and protein phosphatase 2B (PP2B) and localize this protein complex to specific cell compartments. We determined whether an AKAP-signaling protein complex exists in chief cells and whether this modulates secretion. In Western blots, we identified AKAP150, a rodent homologue of human AKAP79 that coimmunoprecipitates with PKA, PKC, and actin. The association of PKA and PP2B was demonstrated by affinity chromatography. Confocal microscopy revealed colocalized staining at the cell periphery for AKAP150 and PKC. Ht31, a peptide that competitively displaces PKA from the AKAP complex, but not Ht31P, a control peptide, inhibited 8-Br-cAMP-induced pepsinogen secretion. Ht31 did not inhibit secretion that was stimulated by agents whose actions are mediated by PKC and/or calcium. However, Ht31, but not Ht31P, inhibited carbachol- and A23187-stimulated augmentation of secretion from cells preincubated with cholera toxin. These data suggest the existence in chief cells of a protein complex that includes AKAP150, PKA, PKC, and PP2B. Disruption of the AKAP-PKA linkage impairs cAMP-mediated pepsinogen secretion and cross talk between signaling pathways.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Proteínas de Transporte/metabolismo , Celulas Principais Gástricas/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Pepsinogênio A/metabolismo , Proteínas de Ancoragem à Quinase A , Actinas/metabolismo , Animais , Calcimicina/farmacologia , Carbacol/farmacologia , Celulas Principais Gástricas/efeitos dos fármacos , Toxina da Cólera/farmacologia , AMP Cíclico/metabolismo , Cobaias , Humanos , Immunoblotting , Ionóforos/farmacologia , Masculino , Microscopia de Fluorescência , Modelos Biológicos , Peptídeos/farmacologia , Testes de Precipitina , Proteína Quinase C/metabolismo
6.
Clin Cornerstone ; 3(6): 13-23, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11501191

RESUMO

Percutaneous liver biopsy, first performed by Paul Ehrlich in 1883, remains an important diagnostic procedure for the management of hepatobiliary disorders. Modern biochemical, immunologic, and radiographic techniques have facilitated the diagnosis of liver disease but have not made biopsy obsolete. Indeed, examination of liver histology remains the "gold standard" for many diagnoses. This article reviews current indications for liver biopsy and the role biopsy plays in managing a variety of disorders.


Assuntos
Hepatopatias/diagnóstico , Fígado/patologia , Biópsia/métodos , Colestase/diagnóstico , Diagnóstico Diferencial , Febre de Causa Desconhecida/etiologia , Hepatite/diagnóstico , Hepatomegalia/diagnóstico , Humanos , Hepatopatias/sangue , Hepatopatias/complicações , Hepatopatias/patologia , Testes de Função Hepática , Neoplasias Hepáticas/diagnóstico , Metotrexato/efeitos adversos
7.
Clin Cornerstone ; 3(6): 37-46, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11501193

RESUMO

With > 100 million people infected worldwide and > or = 4 million people infected in the United States, hepatitis C virus (HCV) is a major public health concern. In the United States, HCV is the most common cause of chronic liver disease. End-stage liver disease from chronic HCV is the most common indication for liver transplantation.


Assuntos
Antivirais/uso terapêutico , Hepacivirus/isolamento & purificação , Hepatite C/tratamento farmacológico , Algoritmos , Análise Custo-Benefício , Quimioterapia Combinada , Hepacivirus/genética , Humanos , Interferons/uso terapêutico , Qualidade de Vida , Ribavirina/uso terapêutico
9.
JAMA ; 285(18): 2331-8, 2001 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-11343480

RESUMO

CONTEXT: Severe gastroesophageal reflux disease (GERD) is a lifelong problem that can be complicated by peptic esophageal stricture and adenocarcinoma of the esophagus. OBJECTIVE: To determine the long-term outcome of medical and surgical therapies for GERD. DESIGN AND SETTING: Follow-up study conducted from October 1997 through October 1999 of a prospective randomized trial of medical and surgical antireflux treatments in patients with complicated GERD. Mean (median) duration of follow-up was 10.6 years (7.3 years) for medical patients and 9.1 years (6.3 years) for surgical patients. PARTICIPANTS: Two hundred thirty-nine (97%) of the original 247 study patients were found (79 were confirmed dead). Among the 160 survivors (157 men and 3 women; mean [SD] age, 67 [12] years), 129 (91 in the medical treatment group and 38 in the surgical treatment group) participated in the follow-up. MAIN OUTCOME MEASURES: Use of antireflux medication, Gastroesophageal Reflux Disease Activity Index (GRACI) scores, grade of esophagitis, frequency of treatment of esophageal stricture, frequency of subsequent antireflux operations, 36-item Short Form health survey (SF-36) scores, satisfaction with antireflux therapy, survival, and incidence of esophageal adenocarcinoma, compared between the medical antireflux therapy group and the fundoplication surgery group. Information on cause of death was obtained from autopsy results, hospital records, and death certificates. RESULTS: Eighty-three (92%) of 90 medical patients and 23 (62%) of 37 surgical patients reported that they used antireflux medications regularly (P<.001). During a 1-week period after discontinuation of medication, mean (SD) GRACI symptom scores were significantly lower in the surgical treatment group (82.6 [17.5] vs 96.7 [21.4] in the medical treatment group; P =.003). However, no significant differences between the groups were found in grade of esophagitis, frequency of treatment of esophageal stricture and subsequent antireflux operations, SF-36 standardized physical and mental component scale scores, and overall satisfaction with antireflux therapy. Survival during a period of 140 months was decreased significantly in the surgical vs the medical treatment group (relative risk of death in the medical group, 1.57; 95% confidence interval, 1.01-2.46; P =.047), largely because of excess deaths from heart disease. Patients with Barrett esophagus at baseline developed esophageal adenocarcinomas at an annual rate of 0.4%, whereas these cancers developed in patients without Barrett esophagus at an annual rate of only 0.07%. There was no significant difference between groups in incidence of esophageal cancer. CONCLUSION: This study suggests that antireflux surgery should not be advised with the expectation that patients with GERD will no longer need to take antisecretory medications or that the procedure will prevent esophageal cancer among those with GERD and Barrett esophagus.


Assuntos
Neoplasias Esofágicas/etiologia , Estenose Esofágica/etiologia , Esofagite/etiologia , Refluxo Gastroesofágico/complicações , Refluxo Gastroesofágico/terapia , Adenocarcinoma/epidemiologia , Adenocarcinoma/etiologia , Esôfago de Barrett/complicações , Causas de Morte , Neoplasias Esofágicas/epidemiologia , Estenose Esofágica/epidemiologia , Esofagite/epidemiologia , Esofagoscopia , Feminino , Seguimentos , Fundoplicatura , Refluxo Gastroesofágico/cirurgia , Fármacos Gastrointestinais/uso terapêutico , Humanos , Concentração de Íons de Hidrogênio , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Ensaios Clínicos Controlados Aleatórios como Assunto , Índice de Gravidade de Doença , Análise de Sobrevida
10.
J Clin Gastroenterol ; 32(1): 37-40, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11154167

RESUMO

Over the past 60 years, the epidemiology of gastric adenocarcinoma has changed considerably. The most striking change in the epidemiology of gastric adenocarcinoma has been the rapid increase in cancers of the proximal stomach. We performed a retrospective analysis of all gastric adenocarcinomas diagnosed at two hospitals in Little Rock, Arkansas, U.S.A., between 1985 and 1996. Two hundred seventeen patients were diagnosed with gastric adenocarcinoma. Patients were divided into three 4-year cohorts. We found that the proportions of gastric cardia adenocarcinoma in cohorts 1, 2, and 3 were 31%, 36%, and 42%, respectively (p = 0.52). Median survival in the three cohorts was 5, 8, and 8 months, respectively (p = 0.22). Median survival (stages 1-4) was 41.5, 11.5, 10, and 3 months, respectively (p < 0.0001). Well-, moderately-, and poorly- differentiated adenocarcinoma had median survivals of 18, 7.5, and 6 months, respectively (p = 0.07). We concluded that patients with gastric adenocarcinoma continue to be diagnosed at late stages. There has been a trend toward an increasing proportion of cardia adenocarcinoma. Stage at presentation was the only significant predictor of survival.


Assuntos
Adenocarcinoma/epidemiologia , Neoplasias Gástricas/epidemiologia , Adenocarcinoma/diagnóstico , Adenocarcinoma/mortalidade , Idoso , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/mortalidade , Taxa de Sobrevida
11.
Am J Gastroenterol ; 95(10): 2975-7, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11051380

RESUMO

In humans, acquired copper deficiency anemia is rare. This report describes a 58-yr-old man with metal pica, especially coins, who presented with symptomatic anemia. His workup led to the diagnosis of zinc-induced copper deficiency. We believe that, in this man, leaching of zinc from pennies explained the clinical and laboratory findings. This case demonstrates that health care workers should consider the possibility of zinc-induced copper deficiency when confronted with patients with unexplained anemia who have ingested coins or other zinc-containing metals.


Assuntos
Cobre/deficiência , Corpos Estranhos/complicações , Numismática , Pica/complicações , Estômago , Zinco/efeitos adversos , Bezoares/complicações , Bezoares/terapia , Corpos Estranhos/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Pica/psicologia , Esquizofrenia Paranoide/complicações , Esquizofrenia Paranoide/psicologia
12.
J Allergy Clin Immunol ; 106(4): 763-8, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11031348

RESUMO

BACKGROUND: Because of the widespread use of peanut products, peanut allergenicity is a major health concern in the United States. The effect or effects of thermal processing (roasting) on the allergenic properties of peanut proteins have rarely been addressed. OBJECTIVE: We sought to assess the biochemical effects of roasting on the allergenic properties of peanut proteins. METHODS: Competitive inhibition ELISA was used to compare the IgE-binding properties of roasted and raw peanut extracts. A well-characterized in vitro model was used to test whether the Maillard reaction contributes to the allergenic properties of peanut proteins. The allergic properties were measured by using ELISA, digestion by gastric secretions, and stability of the proteins to heat and degradation. RESULTS: Here we report that roasted peanuts from two different sources bound IgE from patients with peanut allergy at approximately 90-fold higher levels than the raw peanuts from the same peanut cultivars. The purified major allergens Ara h 1 and Ara h 2 were subjected to the Maillard reaction in vitro and compared with corresponding unreacted samples for allergenic properties. Ara h 1 and Ara h 2 bound higher levels of IgE and were more resistant to heat and digestion by gastrointestinal enzymes once they had undergone the Maillard reaction. CONCLUSIONS: The data presented here indicate that thermal processing may play an important role in enhancing the allergenic properties of peanuts and that the protein modifications made by the Maillard reaction contribute to this effect.


Assuntos
Arachis/imunologia , Hipersensibilidade Alimentar/etiologia , Hipersensibilidade Alimentar/imunologia , Temperatura Alta/efeitos adversos , Alérgenos/imunologia , Alérgenos/fisiologia , Humanos , Imunoglobulina E/metabolismo , Extratos Vegetais/química , Extratos Vegetais/efeitos da radiação , Ligação Proteica/fisiologia , Relação Estrutura-Atividade
13.
Drug Metab Dispos ; 28(10): 1210-6, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10997942

RESUMO

We have recently shown that, in human intestine, glucuronidation of androsterone and testosterone was on the nanomolar level and increased from proximal to distal intestine. In the present study, we have characterized estrogen UDP-glucuronosyltransferase activity in microsomes from intestine of seven human subjects. Intestinal microsomes from all segments of intestine from both males and females (except for one male) glucuronidated estrone (0.2-2.6 nmol/mg x min) and estradiol (0.5-3.1 nmol/mg x min) at levels 2 to 15 times higher than found with human liver microsomes (0.04-0.1 and 0.16-0.25 nmol/mg x min, for estrone and estradiol, respectively). Only with estriol were there significant hepatic glucuronidation (2. 2-4.5 nmol/mg x min) and intestinal glucuronidation activities (0.2-2.2 nmol/mg x min) that were lower than those in liver. All-trans-retinoic acid was glucuronidated by all segments of intestine from both sexes at levels 50 to 80% of those found with human liver but quite low compared with estrogen glucuronidation. In the two subjects for whom stomach was available, there was no measurable activity in stomach microsomes toward any of the substrates. UGT2B RNA expression was examined in mucosa from stomach to colon from two subjects. There was significant expression of UGT2B7, but not of UGT2B4 or UGT2B15, in all segments of intestine. To our knowledge, this is the first direct demonstration of glucuronidation of estrogens by human intestinal microsomes. Thus, in humans, the intestine may be considered as part of the overall mechanism of detoxification via glucuronidation.


Assuntos
Estrogênios/metabolismo , Glucuronosiltransferase/genética , Mucosa Intestinal/metabolismo , Tretinoína/metabolismo , Adolescente , Adulto , Northern Blotting , Linhagem Celular , Estradiol/metabolismo , Estriol/metabolismo , Feminino , Regulação Enzimológica da Expressão Gênica , Ácido Glucurônico/metabolismo , Humanos , Mucosa Intestinal/enzimologia , Intestinos/enzimologia , Masculino , Microssomos/metabolismo , Microssomos Hepáticos/metabolismo , Pessoa de Meia-Idade , RNA/genética , RNA/metabolismo
15.
Am J Gastroenterol ; 95(8): 1914-9, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10950035

RESUMO

OBJECTIVE: Despite recently published national guidelines, many physicians have only limited knowledge about Helicobacter pylori infection. We conducted this study to assess internal medicine residents' knowledge about H. pylori. METHODS: Two hundred and nineteen residents in seven accredited internal medicine training programs completed a self-administered questionnaire on personal demographics and practices related to testing for-and treating-H. pylori infection. RESULTS: Noon conferences (82%), ward teaching (66%), journals (70%), and sponsored symposia (27%) were their major sources of H. pylori-related information. Forty-eight percent had used office-based tests for the infection. Testing for (and treatment of) Helicobacter pylori infection was recommended by 97% (97%) for newly diagnosed duodenal ulcer, but by only 61% (63%) for a past history of duodenal ulcer. Many recommended testing in unproven conditions and might not have offered treatment to an infected patient. A proton pump inhibitor-based triple-drug regimen was the treatment of first choice of 55%; 20% recommended proton pump inhibitor-based dual regimens. Sixty-six percent and 80%, respectively, underestimated the rates of resistance to clarithromycin and metronidazole. In the absence of gastrointestinal symptoms, 22% would have ordered Helicobacter pylori testing but only 33% of these would undergo treatment if positive. CONCLUSIONS: Internal medicine residents usually test for Helicobacter pylori infection in appropriate conditions, but may not always treat the infection when the result is positive. Most use efficacious treatment regimens although many have inaccurate knowledge of resistance rates, which may adversely influence prescribing. Education should focus on practical issues surrounding Helicobacter pylori testing and treatment such as those contained in the American College of Gastroenterology's 1998 practice guidelines.


Assuntos
Coleta de Dados , Conhecimentos, Atitudes e Prática em Saúde , Infecções por Helicobacter , Helicobacter pylori , Medicina Interna/educação , Internato e Residência , Adulto , Resistência Microbiana a Medicamentos , Quimioterapia Combinada , Infecções por Helicobacter/diagnóstico , Infecções por Helicobacter/tratamento farmacológico , Helicobacter pylori/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Inibidores da Bomba de Prótons
16.
Am J Gastroenterol ; 95(8): 2068-73, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10950059

RESUMO

OBJECTIVE: Primary care physicians have imperfect understanding of current colorectal cancer screening guidelines and recommendations. Furthermore, compliance with colorectal cancer screening by internal medicine residents has been demonstrated to be poor. We sought to identify whether current trainees in internal medicine had adequate understanding of colorectal cancer screening and surveillance and test utilization. METHODS: We applied a structured questionnaire about colorectal cancer screening and the use of fecal occult blood tests to 168 internal medicine residents at four accredited programs in the U.S. They were also asked for recommendations about six hypothetical patients who may have been candidates for screening or surveillance. RESULTS: Seventy-one percent identified 50 yr as the currently recommended age to commence screening in an average-risk individual; 64.3% would begin screening with fecal occult blood testing and flexible sigmoidoscopy and 4.8% with colonoscopy. Most perform fecal occult blood testing on stool obtained at digital rectal exam and without prior dietary restrictions. Many use fecal occult blood testing for indications other than colorectal cancer screening. Only 29% recommended colonoscopy to evaluate a positive fecal occult blood test. Most residents plan to be screened for colorectal neoplasia at the appropriate age; significantly more opted for colonoscopy than recommended it for their patients. CONCLUSIONS: Internal medicine residents have many misperceptions regarding colorectal cancer screening and the utility of the fecal occult blood test. Educational efforts should be directed at internal medicine residents, many of whom plan careers in primary care, where most colorectal cancer screening is currently performed.


Assuntos
Neoplasias Colorretais/diagnóstico , Coleta de Dados , Medicina Interna/educação , Internato e Residência , Sangue Oculto , Vigilância da População , Adulto , Colonoscopia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários
18.
Aliment Pharmacol Ther ; 14(7): 887-92, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10886044

RESUMO

BACKGROUND: Omeprazole and lansoprazole can be given in sodium bicarbonate as, respectively, simplified omeprazole suspension and simplified lansoprazole suspension. We previously found the antisecretory effect of omeprazole 20 mg given as simplified omeprazole suspension to be lower than with intact capsules. However, lansoprazole 30 mg as simplified lansoprazole suspension produced an effect similar to that seen with intact capsules. AIM: To evaluate the absorption of both drugs when given orally as capsules or as suspensions in sodium bicarbonate. METHODS: In random order, we gave 5-day courses of omeprazole 20 mg and lansoprazole 30 mg as capsules and as suspensions in sodium bicarbonate to 12 healthy women. Serial blood samples were taken on days 1 and 5 of each course for pharmacokinetic measurements. RESULTS: There was impairment of omeprazole absorption when given as simplified omeprazole suspension. Maximum plasma concentration and area under the concentration/time curve were lower with simplified omeprazole suspension than with omeprazole capsules (P=0.034 and 0.013, respectively, on day 5). No differences were found in lansoprazole absorption when simplified lansoprazole suspension was compared with its standard capsule formulation. Relative bioavailability of omeprazole from simplified omeprazole suspension compared to the capsule was 58.4% on day 5. The corresponding value for lansoprazole was 84.7%. CONCLUSIONS: Simplified omeprazole suspension 20 mg does not supply adequate omeprazole for systemic absorption. Lansoprazole absorption from simplified lansoprazole suspension is maintained.


Assuntos
Omeprazol/análogos & derivados , Omeprazol/farmacocinética , 2-Piridinilmetilsulfinilbenzimidazóis , Absorção , Administração Oral , Adulto , Antiulcerosos/administração & dosagem , Antiulcerosos/farmacocinética , Área Sob a Curva , Cápsulas , Feminino , Humanos , Lansoprazol , Omeprazol/administração & dosagem , Bicarbonato de Sódio/química , Suspensões
19.
South Med J ; 92(6): 558-62, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10372847

RESUMO

BACKGROUND: Mesenteric venous thrombosis is an uncommon but often lethal form of intestinal ischemia. METHODS: We reviewed pertinent literature on mesenteric venous thrombosis using MEDLINE search. RESULTS: We found that previous abdominal surgery and hypercoagulable states are the most common conditions associated with mesenteric venous thrombosis. The symptoms and signs related to mesenteric venous thrombosis are not specific. In the majority of cases, the diagnosis is established by a high index of clinical suspicion and noninvasive imaging techniques. Immediate operation is indicated if signs of peritonitis or intestinal infarction are present. Administration of heparin is beneficial for reducing recurrence and mortality. CONCLUSION: Clinicians should consider the possibility of acute mesenteric venous thrombosis when faced with a patient having abdominal pain out of proportion to the physical findings and with a negative workup for the common causes of abdominal pain.


Assuntos
Oclusão Vascular Mesentérica , Trombose Venosa , Humanos , Oclusão Vascular Mesentérica/diagnóstico , Oclusão Vascular Mesentérica/etiologia , Oclusão Vascular Mesentérica/terapia , Veias Mesentéricas , Trombose Venosa/diagnóstico , Trombose Venosa/etiologia , Trombose Venosa/terapia
20.
J Cell Biochem ; 72(4): 540-8, 1999 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-10022613

RESUMO

Rab3D, a low-molecular-weight GTP-binding protein believed to be involved with regulated exocytosis, is associated with secretory granules in gastric chief cells. Although Rab3D is predominantly membrane associated, a significant fraction is cytosolic. Rab proteins are geranylgeranylated on their C-terminal cysteine motifs by geranylgeranyltransferase (GGTase). Rab escort protein (REP) is required to present Rab proteins to GGTase and may accompany newly modified Rab proteins to their target membrane. In most tissues, cytosolic Rab proteins are complexed with rab-GDP dissociation inhibitor (rab-GDI). In the present study, we examined the interactions of Rab3D with cytosolic proteins in dispersed chief cells. Two REP isoforms and at least two GDI isoforms are present in chief cell and brain cytosol. When chief cell cytosol was fractionated by gel filtration chromatography, Rab3D eluted with REP at >150 kDa, whereas rab-GDI eluted as a separate 65-kDa peak, suggesting that Rab3D exists as a complex with REP, but not with rab-GDI. In addition, a small fraction of Rab3D eluted as a monomer at 29 kDa. As has been demonstrated previously, in brain cytosol, Rab3 proteins co-elute with rab-GDI at approx. 90 kDa, suggesting that Rab3 proteins undergo active cycling between membrane and cytosolic compartments in this tissue. In vitro experiments revealed that Rab3D remains associated with REP after geranylgeranylation. Our findings suggest that, in gastric chief cells, Rab3D remains associated with REP after geranylgeranylation until it is presented to its target membrane.


Assuntos
Alquil e Aril Transferases , Proteínas de Transporte/metabolismo , Celulas Principais Gástricas/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Inibidores de Dissociação do Nucleotídeo Guanina , Proteínas rab de Ligação ao GTP , Animais , Encéfalo/metabolismo , Cromatografia em Gel , Grânulos Citoplasmáticos/metabolismo , Exocitose , Cobaias , Masculino , Prenilação de Proteína , Proteínas rab3 de Ligação ao GTP , Inibidores da Dissociação do Nucleotídeo Guanina rho-Específico
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