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1.
J Psychiatr Ment Health Nurs ; 19(4): 319-26, 2012 May.
Article in English | MEDLINE | ID: mdl-22070523

ABSTRACT

The purpose of this study was to explore the influencing factors in the substantive theory of home care for people with schizophrenia in Taiwan. The grounded theory of Strauss and Corbin approach was used. Semi-structured one-to-one in-depth interviews were utilized to collect data. Constant comparative analysis continued during the open, axial and selective coding processes until data saturation occurred. Participants were selected using theoretical sampling, and the final sample in this study consisted of a total of 29 community nurses (18 public health nurses and 11 home health nurses) who provided community mental health home-visiting services. The public health nurses and home health nurses both conducted a total of 16 (eight carers and eight clients) home visits. Four categories and 12 subcategories of influencing factors were identified; these factors have both positive and negative effects on nursing roles and the functions of public health nurses in the mental health home-visiting service in Taiwan. The influencing factors identified support the importance of home care services.


Subject(s)
Community Mental Health Services , Cross-Cultural Comparison , Schizophrenia/nursing , Schizophrenic Psychology , Adult , Caregivers/psychology , Community Health Nursing , Deinstitutionalization , Female , Health Services Needs and Demand , Home Care Services , Humans , Male , Middle Aged , National Health Programs , Nurse's Role/psychology , Public Health Nursing , Taiwan
2.
J Acquir Immune Defic Syndr ; 28(1): 9-13, 2001 Sep 01.
Article in English | MEDLINE | ID: mdl-11579271

ABSTRACT

OBJECTIVE: To determine the probable site of the nephron and the plasma indinavir (IDV) concentration at which intrarenal IDV crystallization occurs. DESIGN: We performed in vitro crystallization experiments in IDV solutions simulating conditions found in the nephron. METHODS: To determine intrarenal IDV concentrations at which conditions in the nephron allow crystallization, several concentrations of IDV basic solutions (0-800 mM) were titrated from pH 4.0 to higher pH values until crystals formed within 1 minute. Based on the combination of pH and ionic strength at which crystals formed, we determined the site of the nephron at which this combination was first attained. Based on the capacity for concentration at that site, we were able to measure the corresponding plasma IDV concentration. RESULTS: Under conditions normally found at the proximal tubule (i.e., pH 6.7 and ionic strength of 200 mM), IDV crystallized at 200 mg/L. Under conditions applying to the loop of Henle, pH 7.4 and ionic strength of 200 mM, IDV crystallized at 125 mg/L, which would correspond to a plasma IDV concentration of 8 mg/L. CONCLUSIONS: IDV crystallization is most likely in the loop of Henle and may already start at plasma IDV concentrations as low as 8 mg/L. Increasing hydration does not reduce the risk of IDV crystallization in the loop of Henle but instead prevents IDV crystallization and aggregation in the lower urinary tract. It remains to be confirmed whether prevention of high IDV plasma concentrations will reduce the risk of IDV crystallization in the loop of Henle.


Subject(s)
HIV Protease Inhibitors/chemistry , Indinavir/chemistry , Loop of Henle/chemistry , Crystallization , Humans , Hydrogen-Ion Concentration , Solubility
4.
Zhonghua Yi Xue Za Zhi (Taipei) ; 63(7): 552-7, 2000 Jul.
Article in English | MEDLINE | ID: mdl-10934808

ABSTRACT

BACKGROUND: In situ extracorporeal shock wave lithotripsy (ESWL) for upper ureteral stones is controversial, in contrast to ESWL treatment of the majority of other renal calculi. Some urologists recommend retrograde mobilization of the calculi into the renal pelvis prior to ESWL as a routine procedure, while others report little advantage in manipulating a ureteral stone into the kidney before treatment by ESWL. To better understand this controversial issue, we reanalyzed clinical studies and the mechanism of stone disintegration in ESWL. METHODS: We performed a computerized MEDLINE search and manual bibliographic review of relevant peer reviewed reports from 1980 to 1998. Ten reports were analyzed with respect to stone-free rate and the important findings are summarized. RESULTS: Two of 10 data sets are statistically significant (p < 0.05) to verify a higher stone-free rate and another five reports also revealed that higher stone-free rates could be expected with retrograde stone manipulation into the renal collecting system before treatment by ESWL. CONCLUSIONS: Higher stone-free rates with retrograde stone manipulation into the renal collecting system before treatment by ESWL is statistically significant and theoretically supported by the mechanism of stone disintegration.


Subject(s)
Lithotripsy , Ureteral Calculi/therapy , Humans
5.
Oncogene ; 19(28): 3164-71, 2000 Jun 29.
Article in English | MEDLINE | ID: mdl-10918571

ABSTRACT

The protein-tyrosine phosphatase Shp-2 is a positive modulator of the Ras/mitogen-activated protein kinase pathway and a putative substrate of the transforming non-receptor tyrosine kinase v-Src. To characterize the role of Shp-2 in cellular transformation and signaling by v-Src, we expressed v-Src in normal and Shp-2-deficient mouse embryo fibroblasts. Expression of Shp-2 was found to be necessary for morphological transformation by v-Src: Shp-2+/+ cells became rounded or spindly upon v-Src expression, whereas Shp-2-deficient cells remained relatively flat. v-Src-induced reorganization of the actin cytoskeleton and the formation of podosomes were compromised in Shp-2-deficient cells. Shp-2 deficiency also reduced v-Src-induced activation of the anti-apoptotic protein kinase Akt. The reduced activation of Akt in Shp-2-deficient cells correlated with a reduction in the association of the p85 regulatory subunit of PI3-kinase with the adapter protein Cbl. Activation of PI3-kinase by v-Src may be mediated by the association of the adapter protein Cbl with the p85 subunit. Since activation of Akt is dependent on PI3-kinase, this suggests that the effect of Shp-2 on Akt activation may be mediated, at least in part, by its effects on the interaction between PI3-kinase and Cbl. The defect in activation of the Akt survival pathway also correlated with enhanced sensitivity of Shp-2-deficient cells to an apoptosis-inducing agent. These results implicate Shp-2 in v-Src-induced cytoskeletal reorganization and activation of the Akt cell survival pathway.


Subject(s)
Apoptosis , Fibroblasts/cytology , Oncogene Protein pp60(v-src)/metabolism , Protein Serine-Threonine Kinases , Protein Tyrosine Phosphatases/metabolism , Protein-Tyrosine Kinases/metabolism , Proto-Oncogene Proteins/metabolism , src Homology Domains , Animals , Cells, Cultured , Cytoskeleton , Enzyme Activation , Fibroblasts/metabolism , Intracellular Signaling Peptides and Proteins , Mice , Phosphatidylinositol 3-Kinases/metabolism , Protein Tyrosine Phosphatase, Non-Receptor Type 11 , Protein Tyrosine Phosphatase, Non-Receptor Type 6 , Protein Tyrosine Phosphatases/genetics , Proto-Oncogene Proteins c-akt , SH2 Domain-Containing Protein Tyrosine Phosphatases
6.
J Gastroenterol ; 35(6): 460-4, 2000.
Article in English | MEDLINE | ID: mdl-10864355

ABSTRACT

Acrokeratosis paraneoplastica is a rare disease and is uncommon even in patients with upper aerodigestive tract cancer. We report a 63-year-old man with a 1-month history of numerous pruritic lesions and vesicles on both feet. Although he had received local therapy, progressive dense scale formation involving both palms and both soles was found. Colonoscopy was performed because of hematochezia, and it revealed an early colon cancer. After the resection of the cancer, the skin lesions began to fall off dramatically. To the best of our knowledge, there is no report of acrokeratosis paraneoplastica associated with colon cancer in the literature. This is the first case report of acrokeratosis paraneoplastica associated with early colon cancer.


Subject(s)
Acrodermatitis/complications , Adenocarcinoma/complications , Colonic Neoplasms/complications , Keratosis/complications , Paraneoplastic Syndromes/complications , Humans , Male , Middle Aged , Paraneoplastic Syndromes/epidemiology
7.
J Formos Med Assoc ; 99(12): 914-9, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11155744

ABSTRACT

BACKGROUND AND PURPOSE: Craniofacial resection provides multidirectional approaches to remove nasal and paranasal tumors that involve the skull base. The purpose of this study was to determine the survival and local control rate in patients undergoing craniofacial resection for tumors of the nasal cavity, paranasal sinuses, and adjacent areas. METHODS: The medical records of 30 consecutive patients who had undergone craniofacial resection for tumors of the nasal cavity, paranasal sinuses, and adjacent areas were reviewed. The extent of disease, treatment results, complications, and prognoses were analyzed. RESULTS: Lesions were malignant in 28 patients and benign in two. Sixteen of the patients had dural or intradural involvement. There was no surgical mortality, and the rate of surgical morbidity was 7%. The 2-year survival of the 28 patients with malignancies was 46% and the mean follow-up time was 35 months. Local control was achieved in 53% of patients. Nine of 16 patients with dural or intradural invasion had a mean survival time of 17 months. There was no significant difference in the frequency of local control between previously treated and untreated patients. Patients who had a clear margin showed significantly better local control than those with an involved or questionable margin. CONCLUSIONS: Tumors of the nasal cavity and paranasal sinus that involve the skull base can be effectively treated using craniofacial resection, with a reasonable survival and low complication rate.


Subject(s)
Nose Neoplasms/surgery , Paranasal Sinus Neoplasms/surgery , Adolescent , Adult , Aged , Aged, 80 and over , Child , Facial Bones/surgery , Female , Humans , Male , Middle Aged , Nose Neoplasms/mortality , Otorhinolaryngologic Surgical Procedures/methods , Paranasal Sinus Neoplasms/mortality , Survival Rate
8.
Bone Marrow Transplant ; 24(1): 103-7, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10435744

ABSTRACT

Bone marrow transplantation (BMT) has been used for a wide variety of lysosomal storage diseases with encouraging results. We report a 3-year 5-month-old girl with Niemann-Pick type C disease (NPC) who received an allogeneic BMT. The patient presented with repeated lower respiratory tract infections, hepatosplenomegaly, failure to thrive, and developmental delay. Chest computed tomography (CT) revealed diffuse interstitial lung infiltration. Bone marrow and liver biopsies revealed abundant lipid-filled foamy macrophages. Skin fibroblast sphingomyelinase assay revealed partial deficiency. The ability of her skin fibroblasts to esterify cholesterol was very low, and the cells stained brightly for free cholesterol. She received BMT from a healthy HLA-identical male sibling donor at the age of 2 year 6 months. Full engraftment was evidenced by repeated bone marrow sex chromosome studies. Regression of the hepatosplenomegaly, markedly reduced foamy macrophage infiltration in bone marrow, and decreased interstitial lung infiltration was noted 6 months after BMT. Her neurological status, however, deteriorated. Follow-up magnetic resonance image (MRI) revealed progressive, diffuse brain atrophy. We conclude that resolution occurred in the liver, spleen, bone marrow and lung following successful engraftment. Such a response is remarkable since the underlying problem involves a membrane receptor for cholesterol. This positive response might be due to replacement of the monocyte-phagocytic system or it may imply the existence of cross-correction in the NPC membrane receptor defect by BMT approach. Since BMT did not halt the neurological deterioration, it is unlikely to be an adequate treatment for NPC.


Subject(s)
Bone Marrow Transplantation/methods , Niemann-Pick Diseases/therapy , Bone Marrow Transplantation/pathology , Busulfan/therapeutic use , Child, Preschool , Cyclophosphamide/therapeutic use , Female , Humans , Immunosuppressive Agents/therapeutic use , Infant , Male , Niemann-Pick Diseases/drug therapy , Niemann-Pick Diseases/pathology , Transplantation Conditioning/methods
9.
Am J Cardiol ; 83(1): 32-7, 1999 Jan 01.
Article in English | MEDLINE | ID: mdl-10073781

ABSTRACT

Angioplasty of the unprotected left main coronary artery (LMCA) has been controversial. Although recent single-center studies suggest that new devices may change the situation, many questions and problems remain. Therefore, the results of unprotected left main coronary angioplasty of 175 procedures in 107 patients were analyzed to evaluate its feasibility and effectiveness. The treatment of the initial 107 cases included balloon angioplasty (39 cases, 36%), directional coronary atherectomy (53 cases, 50%), and stents (15 cases, 14%). They were divided into 3 major subgroups: (1) acute group (n = 14), in which LMCA angioplasty was performed in patients with acute myocardial infarction; (2) emergency group (n = 10); and (3) elective group (n = 83). In-hospital mortality was higher in the acute (35.7%) and emergency (40.0%) groups than in the elective group (3.6%; p <0.0001). Angiographic follow-up was routinely performed and the restenosis rate including in-hospital restenosis was 70% in the acute group, 37.5% in the emergency group, and 40% in the elective group (p = NS). The mean clinical follow-up period was 2.9 years, and the estimated 5-year survival rates of the acute and emergency groups were 50% and 48.2%, respectively. However the 5-year survival rate of the elective group was higher than that seen in the acute or emergency group (77.5%; p <0.05). Repeat LMCA angioplasty was performed in 37 of 68 patients with 8.8% mortality (38.5% of acute and emergency cases and 1.8% of elective cases). The results indicated that elective unprotected LMCA angioplasty is relatively feasible and effective under scheduled angiographic follow-up.


Subject(s)
Angioplasty, Balloon, Coronary , Coronary Disease/therapy , Coronary Vessels/pathology , Adult , Aged , Aged, 80 and over , Coronary Angiography , Coronary Disease/mortality , Coronary Disease/pathology , Female , Follow-Up Studies , Hospital Mortality , Humans , Male , Middle Aged , Survival Analysis , Treatment Outcome
10.
Am Heart J ; 134(4): 712-8, 1997 Oct.
Article in English | MEDLINE | ID: mdl-9351739

ABSTRACT

Tranilast is an antiallergic drug used widely in Japan that also inhibits the migration and proliferation of vascular smooth muscle cells. This pilot study was undertaken to determine the effectiveness of tranilast on restenosis after successful directional coronary atherectomy. After the procedure, 40 patients (56 lesions, tranilast group) were treated with oral tranilast for 3 months, and 152 patients (188 lesions, control group) did not receive tranilast. Angiographic and clinical variables were compared between the two groups. The minimal lumen diameter was significantly larger in the tranilast group than in the control group at both 3-month (2.08 vs 1.75 mm, p = 0.004) and 6-month follow-up (2.04 vs 1.70 mm, p = 0.003). The diameter stenosis in the tranilast group was smaller than that in the control group both 3 months (28% vs 40%, p = 0.0007) and 6 months (30% vs 43%, p = 0.0001) after the procedure, with a lower restenosis rate (percent diameter stenosis > or =50) in the tranilast group at 3 months (11 % vs 26%, p = 0.03). The number of clinical events over the 12-month period after the procedure was significantly reduced by tranilast administration (p = 0.013). These findings suggest that the oral administration of tranilast strongly prevents restenosis after directional coronary atherectomy.


Subject(s)
Anti-Allergic Agents/therapeutic use , Atherectomy, Coronary , Coronary Disease/prevention & control , ortho-Aminobenzoates/therapeutic use , Aged , Case-Control Studies , Coronary Disease/surgery , Female , Humans , Male , Middle Aged , Recurrence , Treatment Outcome
11.
Br J Urol ; 78(6): 821-5, 1996 Dec.
Article in English | MEDLINE | ID: mdl-9014702

ABSTRACT

OBJECTIVE: To evaluate and compare changes in pulmonary function after retroperitoneoscopic and open surgery. PATIENTS AND METHODS: From June 1994 to October 1995. 11 patients (five men and six women, mean age 44.7 years, range 29-69) underwent retroperitoneoscopic procedures (Group 1) and 11 patients (eight men and three women, mean age 57.5 years, range 22-73) underwent flank-incision procedures (Group 2). The surgery comprised eight adrenalectomies and one each of nephroureterectomy, nephrectomy and pyelolithotomy in Group 1, and five adrenalectomies, four nephroureterectomies, one ureterolithotomy and one excision of a retroperitoneal tumour in Group 2. Pulmonary function tests (PFTs) were performed before and 3 days after surgery; the forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), forced expiratory volume at 25% (FEV25%), FEV1/FVC, vital capacity (VC), total lung capacity (TLC), residual lung volume (RV) and functional residual capacity (FRC) were compared between the groups. The post-operative changes in the PFTs were assessed using a paired t-test and the degree of change in both groups compared using the Mann-Whitney U-test. Other factors possibly influencing PFT were analysed using multiple regression. RESULTS: Pulmonary function was impaired in both groups on the third day after surgery. In Group 2, the FVC, FEV1, FEV25%, VC and TLC had declined significantly (all P < 0.05) from the pre-operative value. In Group 1, only the FVC and VC decreased significantly (P < 0.05). Post-operative pulmonary complications occurred in two patients in Group 2 but in none of those in Group 1, showing that pulmonary function was generally less affected in Group 1 than in Group 2. CONCLUSION: Although pulmonary function was impaired 3 days after surgery in both groups, retroperitoneoscopic surgery, by eliminating a large flank incision, caused less post-operative pulmonary dysfunction than open surgery.


Subject(s)
Laparoscopy/adverse effects , Lung Diseases/etiology , Adult , Aged , Female , Forced Expiratory Volume , Humans , Lung Diseases/physiopathology , Male , Middle Aged , Postoperative Period , Residual Volume , Total Lung Capacity , Vital Capacity
12.
Zhonghua Yi Xue Za Zhi (Taipei) ; 58(1): 66-9, 1996 Jul.
Article in English | MEDLINE | ID: mdl-8870332

ABSTRACT

Endometriosis of the urinary tract is uncommon, and the most common site of involvement is urinary bladder. Two cases of endometriosis of urinary bladder are presented. The first patient, a 39-year-old woman, complained of dysuria during menstruation and the other 37-year-old woman suffered from intermittent gross hematuria. Pre-operative examinations included ultrasonography, computed tomography and cystoscopic biopsy. Case 1 was in premenopausal status, but the serum estrogen level of case 2 was in postmenopausal status because she was given no exogenous estrogen after previous bilateral salpingo-oophorectomy. Endometriosis of urinary bladder rarely occurs in postmenopausal woman without exogenous estrogen replacement. Case 1 received danazole treatment after transurethral resection of bladder tumor and case 2 received partial cystectomy after transurethral resection of bladder tumor. The patients were followed 36 and 4 months, respectively, and the symptoms kept improving during this period.


Subject(s)
Endometriosis/etiology , Urinary Bladder Diseases/etiology , Adult , Endometriosis/surgery , Female , Humans , Urinary Bladder Diseases/surgery
13.
Br J Sports Med ; 29(3): 171-3, 1995 Sep.
Article in English | MEDLINE | ID: mdl-8800850

ABSTRACT

The rehabilitation of the knee with a deficient anterior cruciate ligament (ACL) always presents a great challenge. Isokinetic assessment allows muscle performance to be quantified. The antishear device, introduced by Johnson, has the distinct advantage of minimizing the anterior translation force during isokinetic exercise. In a previous report, there was a significant difference between the Johnson double pad antishear device and the standard single pad device in knee extension. The main purpose of this study was to define a correlation equation such that data generated in the use of the two different devices can be compared for assessment. Ten subjects were tested with the Cybex isokinetic dynamometer with a randomly selected sequence of test speeds. Correlation coefficient (r), regression analysis and paired t tests (P) were performed to estimate the correlation and difference between the two devices. It is concluded that a significant difference in the data generated between the two devices indicated that a single device should be selected to carry out a series of comparisons on a particular subject. However, if the two devices are used in a series of testings, a set of correlation equations has been defined to facilitate such comparison. The findings in this study will widen the application of comparison of isokinetic data in the quantitative approach of rehabilitation of the knee with a deficient anterior cruciate ligament.


Subject(s)
Exercise Therapy/instrumentation , Knee Joint/physiology , Muscle Contraction , Muscle, Skeletal/physiology , Adult , Algorithms , Anterior Cruciate Ligament Injuries , Equipment Design , Ergometry/instrumentation , Female , Humans , Knee Injuries/physiopathology , Knee Injuries/rehabilitation , Male , Range of Motion, Articular , Regression Analysis , Rotation
15.
J Biol Chem ; 270(12): 6966-74, 1995 Mar 24.
Article in English | MEDLINE | ID: mdl-7896847

ABSTRACT

The tumor suppressor p53 protein possesses activities typical of eukaryotic transcriptional activators; p53 binds to specific DNA sequences and stimulates transcription of the target genes. By a series of deletion and domain-swapping studies, we report here that (i) p53 has two auxiliary domains, which have little effect on the DNA binding activity of its core domain but are capable of modulating its transactivation activity in a target site-dependent manner; (ii) p53 contains two cell-specific transcriptional inhibitory domains, I1 and I2, which are active in Saos-2 and HeLa cells but not in HepG2 and Hep3B cells; and (iii) I1 inhibits the activity of several structurally different activating regions. These results demonstrate that the apparent transcriptional activity of p53 is determined by collaborations among its regulatory domains, its target sites, and the cellular environment.


Subject(s)
Saccharomyces cerevisiae Proteins , Transcription Factors , Transcription, Genetic , Tumor Suppressor Protein p53/physiology , Base Sequence , DNA/metabolism , DNA-Binding Proteins , Fungal Proteins/metabolism , Molecular Sequence Data
16.
J Am Podiatr Med Assoc ; 84(5): 219-24, 1994 May.
Article in English | MEDLINE | ID: mdl-8027951

ABSTRACT

The authors evaluated the radiographs of 40 patients (72 feet) under 21 years of age who underwent surgery for symptomatic hallux abducto valgus deformity at Northlake Regional Medical Center. Forty-eight of 72 feet had metatarsus adductus angles greater than 15 degrees. A statistically significant correlation was found between an increasing metatarsus adductus angle and an increasing hallux abductus angle.


Subject(s)
Hallux Valgus/complications , Metatarsus/abnormalities , Adolescent , Child , Foot Deformities/complications , Humans
17.
J Neurochem ; 60(2): 454-60, 1993 Feb.
Article in English | MEDLINE | ID: mdl-8380432

ABSTRACT

Addition of endothelins (ETs) to neuroblastoma-glioma hybrid cells (NG108-15) induced increases in cytosolic free Ca2+ ([Ca2+]i) levels of labeled inositol monophosphates and inositol 1,4,5-trisphosphate [Ins(1,4,5)P3]. The increases in [Ca2+]i elicited by the three ETs (ET-1, ET-2, and ET-3) were transient and did not show a sustained phase. Chelating extracellular Ca2+ in the medium by adding excess EGTA decreased the ET-mediated Ca2+ response by 40-50%. This result indicates that a substantial portion of the increase in [Ca2+]i was due to influx from an extracellular source. However, the increase in [Ca2+]i was not affected by verapamil or nifedipine (10(-5) M). A rank order potency of ET-1 > ET-2 > ET-3 is shown for the stimulated increase in [Ca2+]i, as well as labeled inositol phosphates, in these cells. ATP (10(-4) M) and bradykinin (10(-7) M) also induced the increases in [Ca2+]i and Ins(1,4,5)P3 in NG108-15 cells, albeit to a different extent. When compared at 10(-7) M, bradykinin elicited a five- to sixfold higher increase in the level of Ins(1,4,5)P3, but less than a twofold higher increase in [Ca2+]i than those induced by ET-1. Additive increases in both Ins(1,4,5)P3 and [Ca2+]i were observed when ET-1, ATP, and bradykinin were added to the cells in different combinations, suggesting that each receptor agonist is responsible for the hydrolysis of a pool of polyphosphoinositide within the membrane. ET-1 exhibited homologous desensitization of the Ca2+ response, but partial heterologous desensitization to the Ca2+ response elicited by ATP. On the contrary, ET-1 did not desensitize the response elicited by bradykinin, although bradykinin exhibited complete heterologous desensitization to the response elicited by ET-1. Taken together, these results illustrate that, in NG108-15 cells, a considerable amount of receptor cross talk occurs between ET and other receptors that transmit signals through the polyphosphoinositide pathway.


Subject(s)
Adenosine Triphosphate/pharmacology , Bradykinin/pharmacology , Calcium Channels , Calcium/metabolism , Endothelins/pharmacology , Inositol 1,4,5-Trisphosphate/metabolism , Receptors, Cytoplasmic and Nuclear , Animals , Egtazic Acid/pharmacology , Fura-2 , Glioma , Hybrid Cells , Inositol 1,4,5-Trisphosphate Receptors , Kinetics , Neuroblastoma , Phosphatidylinositol Phosphates , Phosphatidylinositols/metabolism , Radioligand Assay , Receptors, Cell Surface/metabolism , Time Factors
18.
J Neurochem ; 59(3): 1090-8, 1992 Sep.
Article in English | MEDLINE | ID: mdl-1322966

ABSTRACT

Platelet-activating factor (PAF) initiated polyphosphoinositide (polyPI) breakdown and a rise of intracellular calcium concentration ([Ca2+]i) in neuroblastoma x glioma hybrid NG 108-15 cells. The accumulation of [3H]inositol trisphosphate and [3H]inositol bisphosphate was evident within 15 s after PAF stimulation, peaked at 1 min, and then gradually decayed. The increase in [3H]inositol monophosphate level was observed at 30 s, plateaued in 5 min, and was sustained up to 10 min in the presence of 10 mM LiCl. On the other hand, the rise of [Ca2+]i evoked by PAF reached a peak within 8-12 s and returned to basal levels within 1 min as measured in fura 2-loaded cells. When cells were suspended in Ca(2+)-depleted medium, the PAF-induced [Ca2+]i rise was reduced by 80%, indicating that the increase of [Ca2+]i was predominantly due to the Ca2+ influx from an extracellular source. Both PAF-induced accumulation of 3H-labeled inositol phosphates and [Ca2+]i elevation were concentration dependent with EC50 values of approximately 1 x 10(-10) and 5 x 10(-8) M, respectively. The PAF analogs 1-O-hexadecyl-2-hydroxy-sn-glycero-3-phosphocholine and 1-O-hexadecyl-2-O-methyl-rac-glycerol-3-phosphocholine were much poorer agonists at eliciting the same responses in these cells. Pretreatment of cells with pertussis toxin caused a substantial inhibition of PAF-induced accumulation of 3H-inositol phosphates. In contrast, the rise in [Ca2+]i was not significantly affected by toxin treatment at the same concentration.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Calcium/metabolism , Glioma/metabolism , Neuroblastoma/metabolism , Phosphatidylinositols/metabolism , Platelet Membrane Glycoproteins , Receptors, Cell Surface/physiology , Receptors, G-Protein-Coupled , Animals , Cell Membrane/metabolism , Glioma/pathology , Hybrid Cells , Hydrolysis , Neuroblastoma/pathology , Osmolar Concentration , Pertussis Toxin , Platelet Activating Factor/antagonists & inhibitors , Platelet Activating Factor/metabolism , Receptors, Cell Surface/classification , Receptors, Cell Surface/metabolism , Tumor Cells, Cultured , Virulence Factors, Bordetella/pharmacology
20.
Life Sci ; 49(6): 455-63, 1991.
Article in English | MEDLINE | ID: mdl-1650873

ABSTRACT

Leukotriene C4 (LTC4), one of the major constituents of the slow reacting substance of anaphylaxis, induced a dose-dependent hydrolysis of phosphoinositides in [3H]inositol-prelabeled rat basophilic leukemia (RBL-1) cells. The EC50 for LTC4 to elicit the half maximum accumulation of [3H]inositol phosphates (IPs) was around 20 nM. The increase in the formation of [3H]inositol bisphosphate (IP2) and [3H]inositol trisphosphate (IP3) was detectable at 2 min after the stimulation and progressed up to 30 min. Accumulation of [3H]inositol monophosphate (IP1) was observed only during the late phase of 5-30 min in the presence of LiCl. When cells were stimulated with LTC4 and LTD4 together, there was no additive accumulation in [3H]IPs. Pretreatment of cells with either LTC4 or LTD4 resulted in a decrease in production of [3H]IPs on further stimulation with the same agonist. The desensitization appeared to be heterologous since pretreatment of cells with LTC4 attenuated the responsiveness to LTD4. Conversely, pretreatment with LTD4 also diminished the responsiveness to LTC4 markedly. These results suggest that both LTC4- and LTD4-induced hydrolysis of phosphoinositides are mediated through the same effector in RBL-1 cells.


Subject(s)
Basophils/metabolism , Phosphatidylinositols/metabolism , SRS-A/pharmacology , Animals , Basophils/cytology , Borates/pharmacology , Chlorides/pharmacology , Chromatography, High Pressure Liquid , Dose-Response Relationship, Drug , Hydrolysis , Inositol 1,4,5-Trisphosphate/biosynthesis , Inositol Phosphates/biosynthesis , Leukemia, Basophilic, Acute , Lithium/pharmacology , Lithium Chloride , Rats , SRS-A/pharmacokinetics , Serine/pharmacology , Tumor Cells, Cultured
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