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1.
Artigo em Chinês | MEDLINE | ID: mdl-34256487

RESUMO

Objective: To compare the efficacy, advantages and disadvantages of endoscopic CO2 laser cauterization (ECLC) and open neck surgery in the treatment of congenital pyriform sinus fistula (CPSF). Methods: From September 2014 to March 2017, 80 cases with confirmed diagnosis of CPSF received initial treatment at Guangdong Provincial People's Hospital were prospectively analyzed, including 34 males and 46 females, aged 18 to 672 (194.17±141.18) months. They were consecutively divided into endoscopic group and open-surgery group, with 40 cases in each group. Both groups of patients received surgical treatment under general anesthesia. The endoscopic group was treated by endoscopic CO2 laser cauterization, and the open-surgery group underwent the following surgery: first, we performed suspension laryngoscopy examination to confirm the presence of fistula in the bottom of the piriform fossa, then open-neck resection of congenital piriform sinus fistula with recurrent laryngeal nerve and/or lateral branch of superior laryngeal nerve anatomy plus partial thyroidectomy were performed. The data between the two groups were compared, including the operative time, intraoperative blood loss, postoperative pain, average length of stay, neck cosmetic scores, complications and cure rates. All patients were followed up in outpatient clinics. Statistical analysis was performed using SPSS 20.0 software. P<0.05 indicates that the difference is statistically significant. Results: All patients were successfully completed the operation. The operative time, intraoperative blood loss, postoperative pain and average length of hospital stay in the endoscopic group were significantly less than those in the open group [(27.4±5.5) min to (105.8±52.5) min, (0.6±0.5) ml to (33.6±41.5) ml, (1.7±0.9) points to (4.6±0.7) points, (5.9±2.9)d to(8.9±3.3)d, t values were-9.400, -5.031, -16.199, -4.293, P values were all<0.01]; The neck cosmetic score in the endoscopy group was significantly greater than that of the open group [(9.9±0.4) against (5.8±0.9) points, t=25.847, P<0.01]. Compared with the open group (15.0%, 6/40), the complication rate of the endoscopic group (7.5%, 3/40) was not statistically significant (χ²=0.50, P>0.05). Three months after the first treatment, the cure rate in the endoscopic group (82.5%, 33/40) was significantly lower than that in the open-neck group (100.0%, 40/40), χ²=5.64, P<0.05. The follow-up time was 12 months after the last treatment. Eighty cases were followed up and none was lost to follow-up. During the follow-up period, the cure rate of the endoscopy group (97.5%, 39/40) was compared with that of the open group (100.0%, 40/40), and the difference was not statistically significant. Conclusions: In the treatment of CPSF, the two-surgical method each has their advantages. Compared with open-neck surgery, ECLC is simpler, repeatable. ECLC has shorter time in operation and hospital stay, less complications, and less postoperative pain and more precise cosmetic results. It could be preferred for the initial treatment of CPSF and relapsed cases after cauterization. But subject to relatively low cure rate of one-time cauterization and uncertain long-term efficacy, it cannot completely replace the open-neck surgery at present.


Assuntos
Fístula , Lasers de Gás , Seio Piriforme , Dióxido de Carbono , Cauterização , Endoscopia , Feminino , Fístula/cirurgia , Humanos , Lasers de Gás/uso terapêutico , Masculino , Seio Piriforme/cirurgia , Estudos Retrospectivos , Resultado do Tratamento
2.
Artigo em Chinês | MEDLINE | ID: mdl-30121999

RESUMO

Objective: To investigate the anatomic tract of congenital pyriform sinus fistula (CPSF). Methods: A total of 90 patients with CPSF undergoing open surgery between August, 2007 and March, 2017 at the Department of Guangdong General Hospital were retrospectively analyzed. Results: The tracts of all the fistulas actually walked far different from those of theoretical ones. A whole fistula may be divided into 4 segments according to adjacent anatomy of CPSF. The posterior inner segment to the thyroid cartilage was initial part of the fistula. It originated from the apex of pyriform sinus, then piercing out of the inferior constrictor of pharynx inferiorly near the inferior cornu of the thyroid cartilage (ICTC), and descended between the lateral branch of the superior laryngeal nerve and the recurrent laryngeal nerve. The ICTC segment was the second part of the fistula, firstly piercing out of the inferior constrictor of pharynx and/or cricothyroid muscle, and then entering into the upper pole of thyroid. The relationship between fistula and ICTC could be divided into three types: type A (medial inferior to ICTC) accounting for 42.2% (38/90); type B (penetrate ICTC) for 3.3% (3/90); and type C (lateral inferior to ICTC) for 54.5% (49/90). The internal segment in thyroid gland was the third part of fistula, walking into the thyroid gland and terminating at its upper pole (92.2%, 83/90) or deep cervical fascia near the upper pole of thyroid (7.8%, 7/90). The lateral inferior segment to thyroid gland was the last part of the fisula, most of which are iatrogenic pseudo fistula, and started from the lateral margin of thyroid gland. Conclusions: CPSF has a complicated pathway. Recognition of the tract and adjacent anatomy of CPSF will facilitate the dissection and resection of CPSF in open surgery.


Assuntos
Fístula/congênito , Fístula/patologia , Doenças Faríngeas/congênito , Doenças Faríngeas/patologia , Seio Piriforme/patologia , Dissecação , Humanos , Doenças da Laringe/congênito , Doenças da Laringe/patologia , Músculos Laríngeos/patologia , Nervos Laríngeos/patologia , Músculos Faríngeos/patologia , Nervo Laríngeo Recorrente/patologia , Estudos Retrospectivos , Cartilagem Tireóidea/patologia , Doenças da Glândula Tireoide/congênito , Doenças da Glândula Tireoide/patologia , Glândula Tireoide/patologia
3.
Artigo em Chinês | MEDLINE | ID: mdl-29798081

RESUMO

Objective:To identify the pathogenic bacteria of CPSF and their resistance to antibiotics,and guide the rational use of antibiotics therapy.Method:One hundred and thirty cases of deep neck infection whose imaging finding depicted patients with suspected as CPSF were enrolled in the study from January 2010 to June 2017.Specimens were collected from abscesses or other inflammatory lesions from all patients through a small incision or the external orifice on the skin of the neck.Result:A total of 108 strains of pathogens have been isolated from 88 patients (positive rate: 67.7%), among which the gram-positive bacteria accounted for 56.5%, gram-negative bacteria accounted for 43.5%. Streptococcus and Staphylococcus aureus (22.2%) were the most common pathogens among young patients (≤14 years old) (17.7%);Klebsiellapneumoniae (15.7%) were the most common pathogens among the patients over 14 years old. Separation of pathogenic bacteria have maintained a low resistance to most antibiotics. G+ bacteria is totally sensitive to quinupristin/dalfopristin and vancomycin; G-bacteria is totally sensitive to cefoperazone/Batan, piperacillin/tazobactam,imipenem.Conclusion:Most of pathogens come from upper respiratory tract in CPSF cases, and are mostly sensitive to ßlactamase.


Assuntos
Fístula/tratamento farmacológico , Seio Piriforme/patologia , Adolescente , Adulto , Antibacterianos , Farmacorresistência Bacteriana , Fístula/microbiologia , Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Negativas/patogenicidade , Bactérias Gram-Positivas/isolamento & purificação , Bactérias Gram-Positivas/patogenicidade , Humanos , Testes de Sensibilidade Microbiana
4.
Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi ; 52(10): 744-748, 2017 Oct 07.
Artigo em Chinês | MEDLINE | ID: mdl-29050091

RESUMO

Objective: To investigate the feasibility and significance of modified Killian(MK) method in the clinical diagnosis of congenital pyriform sinus fistula(CPSF) by electronic laryngoscopy. Methods: The following examinations were performed for 30 suspected cases of CPSF, including the traditional electronic laryngoscopy, MK examination(modified Killian position+ head rotation+ the Valsalva maneuver), barium swallow X-ray(BSX) and CT , and a prospective comparison among them were done. Patients were divided into two groups according to their age: young age group(≤14 years old) and older age group (>14 years old). The results of MK examination from the patients were analyzed and the positive diagnostic rates (PDR) between groups were compared by using χ(2) tests. Results: Sinuses in 20 of 30 patients were depicted from pyriform sinus in BSX, and the PDR was 66.7%(20/30). The PRD of CT was 83.3%(25/30). The presence of air bubbles around the upper lobe of the thyroid gland or at the inferomedial edge of cricothyroid joints, morphological changes of thyroid grand as well as pseudo-fistula formation on lower neck were detected clearly on CT. Comparing to the traditional electronic laryngoscopy, the effect of exposing piriform fossa fistula by MK examination is significant(χ(2)=17.05, P<0.05), with the PDR of 13.3%(4/30) and 76.7%(23/30) respectively. Nevertheless, comparing to BSX and CT, there were no statistically significant differences in the effect to diagnose CPSF (χ(2)=0.31, χ(2)=0.10 respectively, P>0.05). The PDR of MK in older group is significantly higher than younger group(χ(2)=6.68, P<0.05). Conclusions: MK examination can clearly reveal the hypopharyngeal anatomical structure and detect the sinus of CPSF .It could be a safe, feasible, convenient and economical method as an application in preoperative diagnosis and follow-up examination of clinical suspected CPSF.


Assuntos
Fístula/congênito , Fístula/diagnóstico , Doenças Faríngeas/congênito , Doenças Faríngeas/diagnóstico , Seio Piriforme , Adolescente , Bário , Estudos de Viabilidade , Humanos , Hipofaringe , Laringoscopia/métodos , Pescoço , Postura , Estudos Prospectivos , Rotação , Tomografia Computadorizada por Raios X , Manobra de Valsalva
5.
Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi ; 52(10): 760-765, 2017 Oct 07.
Artigo em Chinês | MEDLINE | ID: mdl-29050094

RESUMO

Objective: To investigate the relationship between Work Ⅱ type of congenital first branchial cleft anomaly (CFBCA) and facial nerve and discuss surgical strategies. Methods: Retrospective analysis of 37 patients with CFBCA who were treated from May 2005 to September 2016. Among 37 cases with CFBCA, 12 males and 25 females; 24 in the left and 13 in the right; the age at diagnosis was from 1 to 76 ( years, with a median age of 20, 24 cases with age of 18 years or less and 13 with age more than 18 years; duration of disease ranged from 1 to 10 years (median of 6 years); 4 cases were recurren after fistula resection. According to the classification of Olsen, all 37 cases were non-cyst (sinus or fistula). External fistula located over the mandibular angle in 28 (75.7%) cases and below the angle in 9 (24.3%) cases. Results: Surgeries were performed successfully in all the 37 cases. It was found that lesions located at anterior of the facial nerve in 13 (35.1%) cases, coursed between the branches in 3 cases (8.1%), and lied in the deep of the facial nerve in 21 (56.8%) cases. CFBCA in female with external fistula below mandibular angle and membranous band was more likely to lie deep of the facial nerve than in male with external fistula over the mandibular angle but without myringeal web. Conclusions: CFBCA in female patients with a external fistula located below the mandibular angle, non-cyst of Olsen or a myringeal web is more likely to lie deep of the facial nerve. Surgeons should particularly take care of the protection of facial nerve in these patients, if necessary, facial nerve monitoring technology can be used during surgery to complete resection of lesions.


Assuntos
Região Branquial/anormalidades , Região Branquial/cirurgia , Fístula Cutânea/congênito , Fístula Cutânea/cirurgia , Nervo Facial , Adolescente , Adulto , Idoso , Região Branquial/patologia , Criança , Pré-Escolar , Fístula Cutânea/patologia , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores Sexuais , Adulto Jovem
6.
Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi ; 31(21): 1684-1687, 2017 Nov 05.
Artigo em Chinês | MEDLINE | ID: mdl-29798128

RESUMO

Objective:Evaluate the application value of modified rhytidectomy incision in superficial parotid gland tumor resection.Method:Seventy-one patients with tumor in the superficial parotid were included in this study from January 2012 to January 2015. They all accepted superficial parotidectomy or subtotal superficial parotidectomy. Thirty-six cases used modified rhytidectomy incision and 35 cases used modified blair incision. The data of operative field exposure, operating time, bleeding, the rate of complication, score of patients's satisfaction were recorded and compared between the two groups.Result:There was no statistically significant difference between the two groups in the operative field exposure, operating time and bleeding (P > 0.05). No difference was found between the two groups in the rate of facioplegia, while the rate of insensible earlobe in the modified rhytidectomy incision group was significantly lower than the modified blair incision group (P < 0.05). The score of patient's satisfaction in the modified rhytidectomy incision group was significantly higher than the other group (P < 0.05).Conclusion:The modified rhytidectomy incision provides good exposure and has the advantage of less complication and better cosmetic outcome. It is worthy of wide clinical application.


Assuntos
Glândula Parótida/cirurgia , Neoplasias Parotídeas/cirurgia , Ritidoplastia , Pavilhão Auricular , Humanos , Satisfação do Paciente , Complicações Pós-Operatórias
7.
Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi ; 51(10): 776-779, 2016 Oct 07.
Artigo em Chinês | MEDLINE | ID: mdl-27765110

RESUMO

Objective: To report rare cases of congenital neck cutaneous sinus with an orifice near the sternoclavicular joint and to investigate their origins and managements. Methods: A total of ten patients with congenital neck cutaneous sinus having an orifice near the sternoclavicular joint treated in the Guangdong General Hospital from January 2010 to June 2015 were retrospectively analyzed. Results: There four boys and six girls, aging from 11 months to 96 months with an average of 33.4 months, and they had a common feature showing a congenital cutaneous sinus with an orifice near sternoclavicular joint. Discharge of pus from the orifice or abscess formation was commonly seen soon after infection. With bacteriological study, staphylococcus aureus was positive in five cases and klebsiella pneumonia in a case. Another orifice of fistula/sinus was not depicted in pyriform with barium swallow X-ray in five cases Ultrasound studies of three cases demonstrated anechoic (i.e., nearly black) and solid-cystic lesion near sternoclavicular joint with posterior acoustic enhancement. Magnetic resonance imaging (MRI) showed isointensity of the lesion on T1 and T2 weighted images with heterogeneous enhancement and a close relationship with sternoclavicular joint. All patients underwent laryngoscopic examination, which showed no orifice of sinus in pyriform at same side. Surgical resection of fistula/sinus was performed in all cases. The lengths of the fistula varied from 5 mm to 22 mm with an average of 11 mm. Postoperative pathological examination showed all specimens were accordance with fistula. No complications were noticed. Recurrence was not observed in the cases by following-up of 6 months to 70 months (median: 33 months). Conclusion: Congenital neck cutaneous sinus with orifice near the sternoclavicular joint maybe a special clinical phenotype of the fourth branchial cleft sinus with skin orifice in cervicothoracic junction. Differential diagnoses between low cervical diseases are required. The curative treatment is a complete excision during inflammatory quiescent period.


Assuntos
Região Branquial/anormalidades , Fístula Cutânea/congênito , Doenças Faríngeas/congênito , Abscesso/diagnóstico , Abscesso/microbiologia , Região Branquial/diagnóstico por imagem , Região Branquial/microbiologia , Região Branquial/cirurgia , Criança , Pré-Escolar , Anormalidades Craniofaciais/diagnóstico por imagem , Anormalidades Craniofaciais/microbiologia , Anormalidades Craniofaciais/cirurgia , Fístula Cutânea/diagnóstico por imagem , Fístula Cutânea/cirurgia , Feminino , Humanos , Lactente , Klebsiella pneumoniae/isolamento & purificação , Imageamento por Ressonância Magnética , Masculino , Pescoço , Doenças Faríngeas/diagnóstico por imagem , Doenças Faríngeas/microbiologia , Doenças Faríngeas/cirurgia , Radiografia , Recidiva , Estudos Retrospectivos , Staphylococcus aureus/isolamento & purificação , Ultrassonografia
9.
Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi ; 30(19): 1545-1547, 2016 Oct 05.
Artigo em Chinês | MEDLINE | ID: mdl-29871137

RESUMO

Objective:To evaluate the therapeutic effect of selective anterior neck dissection on the treatment of children's recurrent thyroglossal duct cysts. Method: The clinical data of 28 patients with recurrent thyroglossal duct cysts were retrospectively analyzed. In accordance with the embryologic and anatomic features of thyroglossal duct cysts, different types of selective neck dissection were applied. Enbloc resection principles were applied to extirpate thyroglossal duct cysts,scarrings and inflammatory granuloma during the operation. Result:All the wounds of 28 patients healed primarily without significant complications including dysphagia, paragammacism, injury of hypoglossal nerve and superior laryngeal nerve. No recurrences were found in all 28 cases with a follow-up period of 24 to 72 months(average 46 months). Conclusion:Selective anterior neck dissection is a safe and effective surgical procedure for the radical treatment of children's recurrent thyroglossal duct cysts.

10.
Cancer Res ; 56(6): 1445-50, 1996 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-8640838

RESUMO

Phosphoprotein p18 was identified originally on the basis of its very high level of expression in leukemic cells of different lineages. Changes in the level of p18 accumulation and phosphorylation associated with induction of differentiation of leukemic cells suggested a potential role for this phosphoprotein in cellular proliferation and differentiation and possibly in malignant transformation. Recent studies have demonstrated that p18 plays an important role in cell cycle progression by serving as a substrate for p34(cdc2) kinase. These studies showed that inhibition of p18 expression in leukemic cells results in growth retardation and accumulation of cells in G(2)-M. In this study, we explore the potential role of p18 in cellular transformation by investigating the effects of inhibition of p18 expression on the malignant phenotype of K562 erythroleukemia cells. These studies show that antisense inhibition of p18 expression in leukemic cells results in growth arrest at a lower saturation density, loss of serum independence, and loss of anchorage-independent growth in vitro. In addition, inhibition of p18 expression results in a marked inhibition of tumorigenicity of leukemic cells in vivo in the severe combined immune deficiency mouse model. These studies demonstrate that the high level of p18 expression in leukemic cells is necessary for the maintenance of the transformed phenotype and suggest p18 as a potential target for antileukemic interventions.


Assuntos
Leucemia Eritroblástica Aguda/metabolismo , Leucemia Eritroblástica Aguda/patologia , Proteínas dos Microtúbulos , Fosfoproteínas/metabolismo , RNA Antissenso/metabolismo , Animais , Antimetabólitos Antineoplásicos/farmacologia , Southern Blotting , Contagem de Células , Divisão Celular/efeitos dos fármacos , Linhagem Celular Transformada/metabolismo , Linhagem Celular Transformada/patologia , Ensaio de Unidades Formadoras de Colônias , Meios de Cultura/química , Feminino , Metotrexato/farmacologia , Camundongos , Camundongos SCID , Fenótipo , Estatmina , Tetra-Hidrofolato Desidrogenase/metabolismo
11.
Blood ; 87(6): 2518-24, 1996 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-8630419

RESUMO

The ability to generate stable high-titer vectors that give rise to high levels of expression of transduced globin genes in erythroid cells is a prerequisite for effective retroviral-mediated globin gene therapy. The human beta-globin gene with its immediate flanking sequences does not contain all the regulatory elements necessary for regulated high-level and position-independent expression in erythroid cells. The regulatory element known as the beta-globin locus control region (BetaLCR) can provide a linked Beta-globin gene with these properties. However, addition of BetaLCR sequences to a retrovirus carrying a beta-globin gene increases its genetic instability. We have developed a new generation of retroviral vectors in which a human gamma-globin gene is placed under the control of the alphaLCR, the major regulatory element of the alpha-globin gene cluster. We demonstrate that these retroviruses are genetically stable in producer cell lines and can be produced at high titers that exceed 5 x 10(6) colony-forming units (CFU)/mL. In addition, we show that the transduced gamma-globin gene can be expressed in the adult erythroid environment of mouse erythroleukemia (MEL) cells at a level comparable to that of a single endogenous Betamaj-globin gene. These retroviruses can also transduce primary murine bone marrow progenitor cells as efficiently as retroviruses that carry the neomycin resistance (neor) gene. This new generation of globin retroviral vectors may prove useful for gene therapy of human beta-globin gene disorders such as sickle cell disease and beta-thalassemia.


Assuntos
Regulação da Expressão Gênica , Vetores Genéticos/genética , Globinas/genética , Proteínas Recombinantes de Fusão/biossíntese , Sequências Reguladoras de Ácido Nucleico , Retroviridae/genética , Anemia Falciforme/genética , Anemia Falciforme/terapia , Células da Medula Óssea , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Ensaio de Unidades Formadoras de Colônias , Dimetil Sulfóxido/farmacologia , Células Precursoras Eritroides/citologia , Células Precursoras Eritroides/efeitos dos fármacos , Células Precursoras Eritroides/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Terapia Genética , Humanos , Leucemia Eritroblástica Aguda/patologia , Regiões Promotoras Genéticas , Proteínas Recombinantes de Fusão/genética , Células Tumorais Cultivadas , Talassemia beta/genética , Talassemia beta/terapia
12.
Oncogene ; 11(4): 743-50, 1995 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-7651738

RESUMO

Wilms' tumor belongs to a small group of pediatric neoplasms that have served as paradigms of human cancers in which recessive mutations play a primary role in tumorigenesis. WT1 is a candidate tumor suppressor gene that is mutationally inactivated in a proportion of both familial and sporadic Wilms' tumors. Recent studies demonstrated that WT1 can partially suppress growth of a Wilms' tumor cell line in vitro and in vivo. We investigated the ability of WT1 to inhibit the expression of the transformed phenotype in non-Wilms' tumor cells. The expression of WT1 cDNA in ras-transformed NIH3T3 cells yielded large, flat cells that exhibited complete contact-inhibition. These morphologic changes were associated with decreased proliferation, suppression of clonogenicity in soft agar and inhibition of tumor growth in nude mice. Moreover, expression of WT1 in non-transformed NIH3T3 cells resulted in similar morphologic changes and profound resistance to transformation by an activated ras oncogene. These studies suggest that tumor inhibition by WT1 in these cells may be achieved by interference with the ras-mediated signalling pathway.


Assuntos
Transformação Celular Neoplásica , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Genes Supressores de Tumor , Genes ras , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética , Células 3T3 , Animais , Divisão Celular , DNA Complementar , Expressão Gênica , Camundongos , Camundongos Nus , Neoplasias Experimentais/genética , Neoplasias Experimentais/patologia , Mapeamento por Restrição , Transdução de Sinais , Proteínas WT1
13.
Cell Mol Biol Res ; 41(2): 103-10, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-8581061

RESUMO

Differentiation of leukemic cells is frequently associated with downregulation of expression of genes that are important for cell proliferation and differentiation. The p18 gene encodes a major cytosolic phosphoprotein that appears to play a role in transducing signals that control the proliferation and differentiation of normal and leukemic cells. Recent reports have shown that p18 expression and phosporylation by p34cdc2 kinase is essential for progression through the cell cycle. It was previously shown that the level of p18 gene expression is markedly reduced when several different leukemic cell lines are induced to differentiate by exposer to a variety of chemical inducers. The mechanism of this downregulation of p18 mRNA expression has not been elucidated. We have explored the mechanism(s) of p18 mRNA downregulation in U937 promonocytic leukemia cells that are induced with phorbol esters to differentiate along a monocyte/macrophage pathway. We find that the half-life of p18 mRNA that is exceptionally stable in uninduced U937 cells does not change significantly with induced differentiation. We also determined that the stability of the p18 mRNA in these cells does not depend on the synthesis of a labile protein. Direct comparison of the transcription of this gene in induced and uninduced U937 cells showed that transcription is the predominant level of regulation of the activity of this gene in leukemic cells.


Assuntos
Diferenciação Celular/genética , Regulação Neoplásica da Expressão Gênica , Leucemia Monocítica Aguda/genética , Proteínas dos Microtúbulos , Fosfoproteínas/genética , Actinas/efeitos dos fármacos , Actinas/genética , Northern Blotting , Diferenciação Celular/efeitos dos fármacos , Cicloeximida/farmacologia , Dactinomicina/farmacologia , Regulação para Baixo , Genes myc/efeitos dos fármacos , Humanos , Leucemia Monocítica Aguda/tratamento farmacológico , Leucemia Monocítica Aguda/patologia , Fosfoproteínas/biossíntese , Fosfoproteínas/efeitos dos fármacos , RNA Mensageiro/química , RNA Mensageiro/metabolismo , Estatmina , Acetato de Tetradecanoilforbol/farmacologia , Transcrição Gênica , Células Tumorais Cultivadas
14.
J Biol Chem ; 269(14): 10312-8, 1994 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-8144611

RESUMO

p18 is a phosphoprotein that is expressed at very high levels in leukemic cells, at moderately high levels in proliferating normal lymphocytes, and at low levels in quiescent lymphocytes. Induction of terminal differentiation of leukemic cells in culture results in a decrease in cellular proliferation. These phenotypic changes are associated with rapid phosphorylation of p18, followed by a more gradual decrease in the level of its mRNA expression. More than 12 different phosphorylation products of p18 have been identified in different cells by high resolution two-dimensional polyacrylamide gel electrophoresis. Previous studies have suggested that p18 may be a substrate for protein kinase C in some cellular processes and protein kinase A in others. In this report, we show that the phosphorylation of p18 increases as cells progress toward the G2-M phases of the cell cycle in proliferating leukemic cells. We have examined the hypothesis that the putative role of p18 in cellular proliferation may be mediated by its involvement in the p34cdc2 kinase signal transduction pathway. We have produced recombinant p18 in bacterial cells and shown that it can be phosphorylated in vitro by purified p34cdc2 kinase with a stoichiometry of 0.86 mol of PO4/mol of substrate. We have used site-directed mutagenesis to demonstrate that the site of p34cdc2 phosphorylation is the serine at position 38. This same site has previously been shown to be phosphorylated in vivo in bovine brain along with another serine at position 25. The observation that p18 gets phosphorylated in the G2-M phases of the cell cycle and the demonstration that p18 is phosphorylated efficiently by p34cdc2 kinase in vitro at a residue that is also phosphorylated in vivo support the hypothesis that p18 may be a physiologic substrate for p34cdc2 kinase in vivo. We have also examined the effect of inhibiting the expression of p18 on cell cycle progression. These experiments demonstrated that antisense inhibition of the expression of p18 in K562 erythroleukemia cells is associated with a decrease in cellular proliferation and accumulation of cells in the G2-M phases of the cycle. The implications of these findings to the proposed role of p18 in the regulation of cellular proliferation are discussed.


Assuntos
Proteína Quinase CDC2/metabolismo , Ciclo Celular , Leucemia Eritroblástica Aguda/metabolismo , Proteínas dos Microtúbulos , Fosfoproteínas/metabolismo , Sequência de Bases , Primers do DNA , Glutationa Transferase/metabolismo , Humanos , Leucemia Eritroblástica Aguda/patologia , Dados de Sequência Molecular , Fosforilação , Proteínas Recombinantes de Fusão/metabolismo , Transdução de Sinais , Estatmina , Células Tumorais Cultivadas
15.
Blood ; 81(4): 1058-66, 1993 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-8381311

RESUMO

A major positive regulatory element has recently been identified 40 kb upstream from the human zeta 2-globin gene. This regulatory element increases the expression of a linked alpha-globin gene in mouse erythroleukemia cells and in transgenic mice. This element has been shown to share many of the structural and functional features of the locus control region (LCR) of the beta-globin gene cluster. We have examined the activity of a small fragment from this regulatory domain (alpha LCR) in a transient expression system. We show that this element is active as an enhancer in the erythroid environment of K562 cells. It is somewhat less effective as an enhancer in the nonerythroid environment of HeLa cells. This alpha LCR fragment does not exhibit promoter specificity because it can activate both the promoter of its endogenous target gene and the heterologous promoter of the SV40 early genes. Although the major activity of this element is mediated by its interaction with the promoter of the alpha-globin gene, some increase in activity is seen when structural elements from the 5' end of the alpha-globin gene are included with the target promoter. In addition, we show that the enhancing activity of the alpha LCR is potentiated by hemin-induction of K562 cells. Whereas phorbol esters that induce megakaryocytic differentiation of K562 cells markedly decrease alpha-globin messenger RNA accumulation, they do not seem to have a negative effect on the activity of the alpha LCR. These studies suggest a role for the alpha LCR in the basal activity of the alpha-globin gene in erythroid cells and in its increased expression seen with erythroid differentiation. The mechanism of negative regulation of alpha-globin gene expression in phorbol-differentiated K562 cells does not appear to be mediated through the action of the alpha LCR.


Assuntos
Regulação da Expressão Gênica , Globinas/genética , Sequências Reguladoras de Ácido Nucleico , Sequência de Bases , Diferenciação Celular/efeitos dos fármacos , Cloranfenicol O-Acetiltransferase/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Células HeLa , Hemina/farmacologia , Humanos , Leucemia Eritroblástica Aguda , Dados de Sequência Molecular , Regiões Promotoras Genéticas , RNA Mensageiro/genética , Vírus 40 dos Símios/genética , Acetato de Tetradecanoilforbol/farmacologia , Transcrição Gênica , Transfecção , Células Tumorais Cultivadas , beta-Galactosidase/genética
16.
J Biol Chem ; 266(31): 21004-10, 1991 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-1939149

RESUMO

p18 is a phosphoprotein that is present in great abundance in acute leukemia blasts and in less abundance in proliferating lymphocytes. This protein undergoes major changes in its state of phosphorylation upon induction of differentiation of leukemic cells in culture. The same protein appears to be involved in a variety of other cellular processes that include regulation of hormone secretion, T cell activation, muscle differentiation, and brain development. In this report, we describe our studies of the regulation of expression of this gene in leukemic cells. We show that the expression of this gene is markedly reduced upon induction of differentiation of a variety of leukemic cells in culture. We use a cDNA clone that we constructed earlier which encodes this protein as a probe to isolate the human chromosomal p18 gene. We characterize the 5' end of this gene in detail and identify its promoter element. We also identify a regulatory element in the first intervening sequence (IVS-1) of this gene which loses its DNase I hypersensitivity upon induction of differentiation of leukemic cells in culture. Our DNase I footprinting experiments demonstrate nuclear protein binding to multiple sequence motifs within its promoter element and its IVS-1 regulatory element. Functional studies using a transient expression system show that deletion of these sequence motifs has profound effects on the expression of this gene. These studies begin to shed some light on the mechanism of regulation of a gene that may be involved in control of cell growth and differentiation and in a variety of other vital cellular processes.


Assuntos
Regulação Neoplásica da Expressão Gênica , Leucemia/genética , Fosfoproteínas/genética , Sequência de Bases , Northern Blotting , Diferenciação Celular , Análise Mutacional de DNA , Genes , Humanos , Técnicas In Vitro , Íntrons , Dados de Sequência Molecular , Regiões Promotoras Genéticas , RNA Mensageiro/genética , Sequências Reguladoras de Ácido Nucleico , Células Tumorais Cultivadas
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