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H M Wang

Publications and source records attributed to H M Wang.

At least 55 records · Page 3Linked to original sources
PubMed1995

Genetic correlation of the orf224/atp6 gene region with Polima CMS in Brassica somatic hybrids.

To identify regions of the mitochondrial genome from the polima or pol male-sterile cytoplasm of Brassica napus that are genetically correlated with cytoplasmic male sterility (CMS) we analyzed mtDNAs of three male-sterile somatic hybrids formed by the fusion of broccoli (B. oleracea L. var. italica) and pol CMS B. napus protoplasts. Fragments characteristic of a 4.5 kb DNA segment that comprises the single organizational difference between sterile pol and fertile cam Brassica mitochondrial genomes were found in all three sterile somatic hybrids. One of these hybrids possessed a mitochondrial genome that was, apart from a limited region around this 4.5 kb CMS-associated segment, collinear with B. oleracea mtDNA. Previous studies have indicated that expression of transcripts spanning the atp6 gene and a chimeric gene, orf24, located on this 4.5 kb DNA segment, is associated with male sterility. The present results indicate that the orf224/atp6 gene region is genetically correlated with male sterility and provide significant additional support for the view that this gene region may be involved in specifying the CMS trait.

Brassica↗
PubMed1995

Involvement of cell cycle and mitogen-activated pathways in induction of parathyroid hormone-related protein gene expression in rat aortic smooth muscle cells.

PTH-related protein (PTHrP) is induced in aortic vascular smooth muscle cells (VSMC) in association with mitogen-stimulated proliferation. In this study we examined the role of the cell cycle in the control of PTHrP gene expression. In asynchronously cycling cells grown in serum-containing medium, PTHrP-immunoreactive cells were enriched in G2+M, as revealed by fluorescence-activated cell sorting using a specific monoclonal antibody. PTHrP messenger RNA (mRNA) increased transiently in cells after release from chemically induced cell cycle blockade; levels increased by 10-fold at 2 h, coincident with expression of histone-4 mRNA and enrichment of VSMC in the early S phase. However, PTHrP mRNA levels then declined abruptly while the proportion of cells in the S phase and histone-4 mRNA levels remained constant for 8 h. When cell cycle-arrested cells were exposed to fresh serum-containing medium, angiotensin-II, or phorbol ester without removing the cell cycle blocking agents, PTHrP mRNA levels were induced over a time course identical to that observed in cells released from the blockade. This suggests that progression through the cycle per se is not necessary for mitogen-induced PTHrP mRNA expression, and that conventional chemical synchronization is not adequate to examine the cell cycle dependency of PTHrP mRNA abundance in VSMC. By contrast, in two different PTHrP-producing carcinoma cell lines, PTHrP and its mRNA were not altered as a function of cell cycle, demonstrating that different mechanisms control PTHrP expression in these cancer cells. In conclusion, constitutive immunoreactive levels of PTHrP are low in normally cycling VSMC (but not cancer cells) and accumulate during the latter stages of the cell cycle, suggesting a role for this protein in the process of smooth muscle cell division. However, separate mechanisms, which are independent of cell cycle, operate through a protein kinase-C-dependent pathway(s) to mediate the stimulation of PTHrP gene expression by vasoconstrictors such as angiotensin-II.

Animals↗
PubMed1995

Cisplatin and 5-fluorouracil as neoadjuvant chemotherapy: predicting response in head and neck squamous cell cancer.

In order to prospectively evaluate the efficacy, toxicity and predictive factors of response to neoadjuvant chemotherapy, a total of 120 patients with head and neck squamous cell cancer diagnosed from January 1992 to November 1993 were enrolled in this study. There were 118 male and 2 female patients, with a median age of 51 years (range 30-74 years). The primary sites were the oral cavity (77), oropharynx (15), hypopharynx (25) and larynx (3). Betel quid chewing was habitual in 91% of patients. All patients were previously untreated, and 94% had stage III or IV disease. Chemotherapy was given in two or three courses to 96 patients who were then assessed for response rate and predictive factors. The chemotherapy regimen consisted of cisplatin 100 mg/m2/day on day 1 and 5-fluorouracil (5-FU) 1 g/m2/day intravenous infusion continuously for 4 to 5 days for 4 weeks. The overall chemotherapy response rate was 56%, with a 3% complete response. By univariate analysis, both the T-stage and tumor volume were significant for predicting the response of the primary site. The age, histologic differentiation, tumor location and N-stage were unpredictive for response. The nodal response (43%) was less than that of the primary site (68%). By multivariate analysis, only the tumor volume (> or = 50 cm3) and the presence of nodal metastases were predictive for the combined TN response. Based on the World Health Organization toxicity criteria, 49 patients experienced grade 3 to 4 mucositis, and 24 patients had grade 3 to 4 vomiting.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Methotrexate loaded acrylic cement in the management of skeletal metastases. Biomechanical, biological, and systemic effect.

Skeletal metastases occur commonly, and frequently are complicated by the development of an impending or pathologic fracture. In the majority of instances, these patients are best treated by internal stabilization, frequently supplemented by methylmethacrylate, to relieve pain and maintain the patient's mobility. The underlying tumor may continue to grow, and if this occurs the progressive lysis may result in loosening and subsequent failure of the implant. To prevent additional local growth, postoperative radiotherapy is recommended, and many patients also receive endocrine or chemotherapy, but the adjuvant therapy is not always successful in preventing progressive local tumor induced osteolysis. It is possible that the addition of chemotherapeutic agents to the methylmethacrylate may inhibit local growth. This study was performed to determine the biomechanical, biologic, and systemic effects of adding methotrexate to methylmethacrylate. The results show that the addition of methotrexate in as much as a concentration of 2 g methotrexate per 40 g cement did not significantly alter the biomechanical characteristics of the bone cement. The incorporated methotrexate was released continuously from the loaded bone cement, and in the amount and concentration used did not have any toxic effects on the host animal. The methotrexate did not appear to be affected by the heat of polymerization and had a significant systemic effect. There was a significant reduction in pulmonary metastases with methotrexate loaded cement as compared with unloaded cement, the effect being dependent on the concentration of methotrexate in the cement. The results of these studies indicate that methotrexate loaded cement may have an important role to play as part of the orthopaedic management of impending and pathologic fractures.

Animals↗
PubMed1995

A clinical study of colorectal cancer accompanied by cancer of other organs.

BACKGROUND: The incidence of double primary neoplasms has increased in recent decades. The etiologies and epidemiologies of double primary neoplasms are under investigation, and relationships between some cancers are well established. A group of patients with double primary cancers was studied to determine the relationships between certain cancers. METHODS: From November 1982 to September 1993, 48 patients with colorectal cancer accompanied by cancer of another organ (double primary cancers) were treated here. The male-to-female ratio was 31 to 17. According to Warren's definitions, the patients were classified into two groups: synchronous and metachronous. Data collection was done on the basis of locations, pathological staging and interval between cancers. RESULTS: Among the 48 patients, extracolonic cancers were mainly found in the cervix (8), stomach (7), prostate (5), lung (5), urinary bladder (4), and breast (4). In the female patients, 88.2% (15/17) of extracolonic cancers were in the female reproductive organs. In male patients, 45% (14/31) of extracolonic cancers were GI tract neoplasms, and 35.5% (11/31) were cancers of the GU tract. Nearly half of the patients expired within two years after diagnosis of the second primary cancer. CONCLUSIONS: Cancers of the cervix, stomach, prostate, lung, urinary bladder and breast may have some etiologic factors in common with that of colorectuim. Thus, attention should be paid to these sites during the period of post-operative follow-up of the first primary cancer.

Adult↗
PubMed1995

Osteosarcoma of jaw: the experience of Chang Gung Memorial Hospital.

Seven cases with Osteosarcoma (OS) of the jaw were retrospectively reviewed. There were five female and two male patients. Their ages ranged from 14 to 57 years with a mean of 39 years. Seventy-one percent of the patients were older than 30 years old. Jaw swellings were the most frequent complaints occurring on an average of 3 months before diagnosis. Four cases occurred in mandible and three cases developed from maxilla. Most cases were lytic lesions on roentgenography. Four were osteoblastic, 2 were chondroblastic, and 1 was histologic classification. Six of the 7 cases received surgery. Postoperatively, 3 of them received both radiotherapy and chemotherapy, 1 received chemotherapy only and 1 received radiotherapy only. One case received palliative chemotherapy only because of the locally far advanced disease. Four cases died of regional failure without any metastatic lesions (survival ranged from 5 months to 22 months). Two cases survived more than 4 years without any recurrence. The median survival time was 22 months. We concluded that OS of the jaw has different natural courses from OS of the long bones and the regional failure seems to be the main problem in jaw OS.

Adolescent↗
PubMed1994

Transforming growth factor-beta regulates human retinal pigment epithelial cell phagocytosis by influencing a protein kinase C-dependent pathway.

BACKGROUND: Transforming growth factor-beta (TGF-beta) plays an important role in the pathogenesis of many ocular diseases, including proliferative vitreoretinopathy. We examined the effect of TGF-beta on the phagocytosis of rod outer segments by retinal pigment epithelium (RPE), which is a major function of RPE, and investigated the dependence of this effect on the protein kinase C (PKC) pathway. METHODS: Phagocytotic uptake of fluoresceinated bovine rod outer segments was determined by flow cytometry. RPE cells were treated with TGF-beta 1 or TGF-beta 2 and their effects on phagocytosis were examined. The effects of various PKC inhibitors (calphostin C, staurosporine, and extended exposure to phorbol 12-myristate 13-acetate, PMA) and a stimulator (brief exposure to PMA) on RPE phagocytosis was evaluated. RESULTS: Both TGF-beta 1 and TGF-beta 2 up-regulated RPE phagocytosis and PMA abolished the up-regulating effect of TGF-beta. In contrast, PKC inhibition by staurosporine and calphostin C resulted in increased phagocytosis. A combination of TGF-beta and PKC inhibitor treatment did not produced any additive effect on phagocytosis. CONCLUSION: We concluded that TGF-beta up-regulates human RPE phagocytosis, but that this effect is counteracted by PKC activation. It is possible that this TGF-beta-induced effect is due, in part, to a negative modulation of the PKC-dependent pathway.

Alkaloids↗
PubMed1994

Expression and insulin-like growth factor-dependent proteolysis of insulin-like growth factor-binding protein-4 are regulated by cell confluence in vascular smooth muscle cells.

Insulin-like growth factor (IGF)-I is markedly induced after balloon injury in the rat aorta, where it may serve to mediate vascular repair. Because the bioavailability of IGF-I is modulated by IGF-binding proteins (IGFBPs), we examined the regulation of IGFBPs by IGFs in primary cultures of rat aortic smooth muscle cells (SMCs). Serum-deprived SMC-conditioned medium contains IGFBPs of 38 to 45 kD (only in confluent cultures), 30 kD (possibly IGFBP-2), 28 kD, and 24 kD (IGFBP-4), the latter being the most abundant. IGF-I and IGF-II but not insulin evoked a marked decrease of IGFBP-4 as early as 4 hours after treatment. IGFBP-4 mRNA abundance, however, was entirely unaffected by IGF-I for up to 48 hours. IGF-I analogues with high affinity for the IGF-I receptor and weak affinity for IGFBP paradoxically evoked a small increase in IGFBP-4, probably through a general increase in protein synthesis. IGF-I only minimally decreased IGFBP-4 content in medium of sparse cultures, whereas it completely abolished IGFBP-4 content in conditioned medium of superconfluent SMCs. IGF-I also evoked a concentration-dependent increase in the abundance of IGFBP-3 in confluent, but not sparse, SMCs without affecting IGFBP-3 mRNA. Addition of IGF-I to cell-free medium conditioned by confluent, but not by sparsely cultured, SMCs led to rapid degradation of IGFBP-4. Interestingly, IGFBP-4 mRNA was markedly induced in confluent relative to sparsely grown SMCs in an IGF-I independent fashion. Thus, both biosynthesis and IGF-dependent proteolysis of IGFBP-4 are increased in confluent SMCs. Proteolysis was maximal at 37 degrees C and was abrogated by EDTA and by benzamidine. Phenylmethylsulfonyl fluoride and the plasmin inhibitor bdellin had minor inhibitory activity, whereas aprotinin, angiotensin-converting enzyme inhibitors, and N-ethylmaleimide were without effect. The protease does not affect the structure of IGF-I as determined by reverse-phase high-performance liquid chromatography and size-exclusion chromatography of 125I-IGF-I incubated for up to 24 hours with SMC-conditioned medium containing IGFBP-4. In summary, SMCs elaborate a cation-dependent protease in a confluence-dependent fashion, which degrades bound IGFBP-4 and likely releases free structurally intact IGF-I, presumably to interact with the cell surface receptor and/or other IGFBPs.

Animals↗
PubMed1994

Mechanical stimuli induce vascular parathyroid hormone-related protein gene expression in vivo and in vitro.

PTH-related peptide (PTHrP), the factor mediating the syndrome of humoral hypercalcemia of malignancy, is also expressed in smooth muscle cells (SMC) of the urinary bladder and uterus in response to mechanical distention and fetal occupancy, respectively. Vascular SMC also produce PTHrP, and its expression is induced by serum and vasoconstrictors, such as angiotensin-II. To determine whether mechanical distension affected vascular PTHrP gene expression, the abdominal aorta of adult male rats was balloon-distended, and aortae were collected at various times after the intervention. PTHrP mRNA was determined by competitive reverse transcriptase-polymerase chain reaction, using sequential dilutions of a cloned internally truncated PTHrP RNA fragment as standard. The molar concentration of PTHrP mRNA was obtained by extrapolating at a standard/wild-type band intensity ratio of 1:1. Aortic PTHrP mRNA was induced from a basal level of 19, to 22, 46, 36, 13, 12, 22, and 20 attamoles/mg total RNA 1, 2, 12, 24, and 48 h and 7 and 48 days after balloon distension, respectively. To determine whether mechanical events directly regulate vascular PTHrP gene expression, primary rat aortic SMC were plated and placed on a rocking device at 20 oscillations/min to create a gentle flowing motion of the culture medium. Rocking induced PTHrP mRNA of SMC exposed to either serum-free medium or 10% serum by 2.5-and 4.0-fold at 4 h, and 2.9- and 3.7-fold at 24 h, respectively. These effects were oscillation rate dependent, potentiated by angiotensin-II, and specific, as similar changes were not observed in alpha-actin mRNA content. Flow motion-induced PTHrP mRNA at 24 h was partially decreased by 10(-6) M colchicine (which inhibits microtubule assembly), but not by cytochalasin-E (which disrupts actin polymerization). As PTHrP is a known vasorelaxant, we propose that mechanical events induce the release of PTHrP by SMC, possibly to serve as a compliance factor or an agent for vascular remodeling.

Alkaloids↗
PubMed1994

Dexamethasone induced proliferation of cultured retinal pigment epithelial cells.

Dexamethasone (DEX) is a glucocorticoid that is widely used after vitreoretinal surgery and may have mitogenic properties. This study was initiated to determine if human cultured retinal pigment epithelium (RPE) cells express glucocorticoid receptor and proliferate in response to DEX stimulation. Glucocorticoid receptor mRNA was detected in RPE cells by means of reverse transcriptase polymerase chain reaction. To determine the effect of DEX on RPE cell proliferation in vitro, we cultured human RPE cells with various concentrations for DEX for 5 days and determined the effects on cell number and incorporation of tritiated thymidine. DEX treatment with a DEX dose of 1 microgram/ml in the presence or absence of serum resulted in a maximal 2-3 times increase in cell number. Autoradiography after thymidine incorporation revealed a greater than 2-fold increase in incorporating cells at this same dose. These results indicate that DEX causes cultured human RPE cells to proliferate and suggest that it may have a growth factor-like action.

Cell Count↗
PubMed1994

Long term effects of diaminophenoxypentane in the rat retina: protection against light damage.

The retinotoxic drug diaminophenoxypentane (DAPP) was administered to rats to determine its long term effects on rhodopsin levels, retinal morphology and the retina's susceptibility to damage from visible light. In rats given 2 intraperitoneal injections of DAPP at doses of 65 mg/kg body wt, there was a dramatic and sustained loss of rhodopsin. One wk later visual pigment levels were 41% lower than in comparable dark maintained rats injected with saline. Rhodopsin levels in the DAPP treated rats remained lower than in control animals for the 13 wk period of the study. Morphologically, the ROS of rats 1-2 wks after DAPP treatment exhibited some disorganization and shortening; the RPE was unremarkable. Seven wks after DAPP treatment an occasional focal area of damage was seen in the RPE. Similarly, focal areas of degeneration were seen in the outer nuclear layer between the rows of photoreceptor cells. As determined by photoreceptor cell nuclear counts, the retinotoxic effect of DAPP persisted long after drug administration. In the treated rats the loss of visual cell nuclei was 11% at 7 wks; it was 22% 13 wks after DAPP treatment. Immediately after exposure to intense visible light, damage was seen in both the photoreceptor cells and RPE of DAPP treated rats. However, the effects of exposure in the treated rats were less dramatic than in retinas from rats without DAPP treatment. Following a 2 wk dark recovery period, the DAPP treated rats had a normal appearing retinal morphology and an intact RPE layer. The retinas of rats without DAPP treatment showed extensive visual cell and RPE loss.(ABSTRACT TRUNCATED AT 250 WORDS)

Aniline Compounds↗
PubMed1994

Effect of leukopenia on experimental post-traumatic retinal detachment.

Macrophages are invariably present in the intraocular membranes of patients with traumatic proliferative vitreoretinopathy (PVR). There are two sources from which these macrophages could be recruited: adjacent tissues and the systemic circulation. In the study described herein, the role of circulating white blood cells and monocytes in experimental, traumatic PVR was studied. The circulating white blood cells of 20 rabbits were depleted by intravenous injection of strontium-89. Posterior perforating eye injury with subsequent intravitreal injection of autologous whole blood or autologous activated macrophages was then performed on these leukopenic animals. The experiments demonstrated that severe bone marrow depression reduced significantly the incidence of retinal detachments in eyes receiving whole blood, and reduced the severity of retinal detachments in eyes injected with activated macrophages. An association between the degree of leukopenia, monocytopenia, and protection from retinal detachment was demonstrated. These results support the hypothesis that macrophage infiltration is an important component of intraocular cellular proliferation, but does not exclude the role of other types of white blood cells in the pathogenesis of PVR.

Animals↗
PubMed1994

[The effect of iron deficiency anemia on the auditory brainstem response in infant].

Our study attempts to explore the mechanism by which iron deficiency anemia (IDA) affects the brain function of infants. We made auditory brainstem response (ABR) test for 48 IDA infants and 30 normal control infants, aged 6-36 months and reexamined ABR in 4 IDA infants after three months iron therapy. 26 cases of abnormal ABR among 48 IDA infants were found, it took 54.2% of total IDA infants. IDA led mainly to peripheral impairments of auditory system and rarely to brainstem. There was a direct relationship between the severity of IDA and the degree of abnormality of the ABR in infants. The threshold of ABR in IDA infants was significantly higher than that of in control group. It suggests that IDA infants have listening comprehensive difficulty as a result of impairment in high frequency hearing. After follow-up of 4 IDA infants, it was found that the impairment of auditory system could be reversible after prompt correcting of IDA. This observation has important significance for child health in the future.

Anemia, Hypochromic↗
PubMed1993

Substrate specificity of the heparin lyases from Flavobacterium heparinum.

A detailed knowledge about the substrate specificities of the heparin lyases is necessary when using these enzymes as tools for elucidating the sequence of heparin and heparan sulfate. The substrate specificity of heparin lyases I, II, and III have been profiled with structurally defined, heparin-derived oligosaccharides. The primary substrate specificities of heparin lyases I and III require the presence of 2-O-sulfated alpha-L-idopyranosyluronic acid and beta-D-glucopyranosyluronic acid residues, respectively, at the linkages being cleaved. Heparin lyase II demonstrates an intriguingly broad primary specificity for oligosaccharides, acting at linkages containing alpha-L-idopyranosyluronic and beta-D-glucopyranosyluronic acid as well as at linkages containing alpha-L-galactopyranosyluronic acid residues. In addition to their primary specificities, each lyase also demonstrates secondary specificities under forcing conditions. Differences in the sulfation pattern within uronic acid residues and sulfation of adjacent residues has profound impact on the ease of lyase cleavage of a glycosidic linkage. Specifically, heparin lyases I and III exhibit secondary specificity for oligosaccharides containing an unsulfated alpha-L-idopyranosyluronic acid residue. The lack of sulfation on residues adjacent to the linkage undergoing cleavage increases the action of heparin lyase III on a glycosidic linkage. In contrast, reduced sulfation on adjacent residues make glycosidic linkage resistant to heparin lyase I. The primary and secondary specificity can be rationalized on the basis of most favorable solution conformation of the uronic acid residues.

Carbohydrate Conformation↗
PubMed1993

Specificity studies on the heparin lyases from Flavobacterium heparinum.

An understanding of the substrate specificity study of the heparin lyases (heparinase and heparitinases) is crucial for elucidation of the sequence of heparin and heparan sulfate. Four chemically modified heparins have been used to study the substrate specificity of the three heparin lyases. These modified heparins include the N- and O-desulfated and then specifically N-sulfated or N-acetylated derivatives of heparin and a modified heparin containing L-galactopyranosyluronic acid residues. These chemically modified heparins were degraded to various extents by the three heparin lyases. Differences in degree of sulfation have profound impact on the ease of cleavage of glycosidic linkages. Heparin lyase I (EC 4.2.2.7) is selective in cleaving highly sulfated polysaccharide chains containing linkages to 2-O-sulfated alpha-L-idopyranosyluronic acid residues. Heparin lyase III (EC 4.2.2.8) cleaves linkages that have reduced density of sulfation and that contain beta-D-glucopyranosyluronic acid residues. The ability of heparin lyase III to act on linkages to unsulfated alpha-L-idopyranosyluronic acid residues is observed for the first time. Heparin lyase II (no assigned EC number) demonstrates an unparalleled, wide specificity for substrates comprised of linkages containing both alpha-L-idopyranosyluronic and beta-D- glucopyranosyluronic acid residues. Heparin lyase II can also act on substrates containing linkages to unnatural alpha-L-galactopyranosyluronic acid residues. The high level of specificity of heparin lyase I makes it particularly suitable for use in the sequencing of heparin and heparan sulfate, while caution must be exercised in using heparin lyases II and III to sequence heparin and heparan sulfate because of their relatively broad specificity.

Acetylation↗
PubMed1993

Spontaneous gastroduodenal perforation in patients with cancer receiving chemotherapy and steroids. Report of four cases combining 5-fluorouracil infusion and cisplatin with antiemetics dexamethasone.

BACKGROUND: Spontaneous gastroduodenal perforation is an uncommon but life-threatening complication of systemic chemotherapy and/or steroids. Here, the authors reported four cases of gastroduodenal perforation following combined chemotherapy with steroids. METHODS: The chemotherapeutic regimens all included 5-fluorouracil (5-FU) by continuous infusion and cisplatin. The authors used dexamethasone as an antiemetic. All patients took analgesics for pain relief. No patient had a history of peptic ulcer disease. RESULTS: Severe epigastralgia occurred 3-5 days after the start of chemotherapy. The peptic ulcer perforations were diagnosed within 3 days of onset of symptoms. All patients had an emergency laparotomy. Three of the perforations were located in the duodenum and one was located in the stomach. Pathologic examination of one patient revealed a chronic peptic ulcer. Two patients with preoperative shock died in the postoperative period. CONCLUSIONS: The cause of spontaneous gastroduodenal perforation is not known, but the etiology can be complex. Either 5-FU or steroids can induce the perforation. An asymptomatic peptic ulcer may be aggravated by 5-FU, cisplatin, or dexamethasone. The authors suggest that patients receiving 5-FU infusion and cisplatin with dexamethasone for antiemesis who complain of epigastric pain should be mentioned for a gastroduodenal ulcer or even a perforation.

Adult↗
PubMed1993

Ligand-dependent activation of chimeric receptors with the cytoplasmic domain of the interleukin-3 receptor beta subunit (beta IL3).

beta IL3 (formerly known as AIC2A), a beta subunit of the murine interleukin-3 receptor (IL-3R), is not only required for formation of the high affinity receptor but is also important for signal transduction. To examine the function of beta IL3 in signal transduction, we constructed several chimeric receptors consisting of the intracellular portion of beta IL3 and the extracellular portion of other members of the cytokine receptor superfamily, i.e. the human interleukin-2 receptor beta chain (hIL-2R beta), the human interleukin-4 receptor (hIL-4R), and the murine erythropoietin receptor (mEpoR). These chimeric receptors and normal cytokine receptors were expressed in an IL-3-dependent murine pro-B cell line, Ba/F3, and an IL-2-dependent murine T cell line, CTLL2. Regardless of the origin of the extracellular domain, these chimeric receptors were functional in Ba/F3 cells; they stimulated proliferation and induced tyrosine phosphorylation in response to the cytokine corresponding to the extracellular domain. However, the response of transfectants expressing chimeric receptors was similar to, but not identical with, the response of Ba/F3 cells to mIL-3. We present evidence that the IL-4R and EpoR probably have an additional component which is involved in signal transduction.

Animals↗