Immunohistochemical and pathological characteristics of dystrophic amyloid in surgically excised cardiac valves

One hundred and thirty-six cardiac valves obtained surgically from 124 patients (aged 15-77 years) were examined. Microdeposition of amyloid was present in sclerotic or sclerocalcific lesions of aortic valves in 38 out of 75 (51%) and mitral valves in 21 out of 61 (34%). Amyloid deposition was not significantly related to the age of the patients. An antiserum raised against a low molecular weight protein extracted from amyloid-laden valvular tissues (about 20 g) reacted positively to amyloid in the cardiac valves. It did not react to amyloid deposition containing fibril proteins including light chain related amyloidosis, reactive amyloidosis, systemic senile amyloidosis, isolated atrial amyloidosis, beta-2-microglobulin related amyloidosis and beta protein related amyloidosis. Further, amyloid in the cardiac valves failed to react immunohistochemically to anti-AA, anti-AL, anti-TTR, anti-ANF, anti-beta 2M and anti-beta protein antibodies. These findings suggest that an unknown amyloid protein is involved in the damaged valves.

Potentiation of antitumor effect of bleomycin by local electric pulses in mouse bladder tumor

C3H mice bearing subcutaneously transplanted mouse bladder carcinoma (MBT-2) were treated with intramuscular injection of bleomycin followed by local delivery of electric pulses at the tumor site. The tumors markedly reduced and even disappeared for several days after this treatment. Neither electric pulses nor bleomycin administration alone showed a significant inhibitory effect on the tumor growth. Thus, it is demonstrated that in mouse bladder tumor the antitumor effect of bleomycin can be considerably potentiated by local electric pulses.

F wave change by decreased motoneuronal excitability: a sleep study

To clarify the effect of the change in motoneuronal excitability on the F wave, we studied the persistence, mean size, and minimum latency of the F wave in nine normal subjects while awake and asleep. Recordings were made from the abductor pollicis brevis muscle by stimulating the median nerve at the wrist. The persistence and size of the F wave markedly decreased during sleep, especially in stage REM. The mean size in stage REM was less than 5% of that in stage W in most subjects, and the F wave entirely disappeared in one subject. The minimum latency during sleep was longer than during wakefulness. Prolongation was within 2.0 ms when the persistence was more than 10%. A decrease in the number of motoneurons that elicit the F wave may be the major cause of prolongation. We conclude that the decreased motoneuronal excitability can cause the F wave to disappear without conduction block in the peripheral motor nerve and that the prolongation of the F wave for more than 2 ms provides a marker for proximal conduction delay in the clinical nerve conduction studies.

[Flow cytometric analysis of prostatic adenocarcinomas after hormone therapy]

A DNA ploidy pattern of prostatic adenocarcinoma was studied by flow cytometry using the formalin-fixed, paraffin-embedded tissues obtained from 65 patients. These patients received hormone therapy preoperatively. Forty cases (61.5%) showed a diploid pattern, and 25 (38.5%) an aneuploid pattern. Comparing this ploidy pattern with histological classification, the aneuploid pattern was found in 13 cases (52%) of poorly differentiated group, 12 cases (48.0%) of moderately differentiated group and 0 case (0%) of well differentiated group. Thus, rate of aneuploid pattern increased with an increase in the grade of malignancy. Five years survival rate was 62.6% in the diploid group while it decreased to 30.9% in the aneuploid group. There was a significant difference between the two groups. In 23 cases with stage D, the ploidy pattern of primary region could be compared with that of metastatic region (lymph nodes). The prognosis of patients who exhibited the aneuploid pattern in metastatic region was significantly worse than that of other patients. These data suggested that flow cytometric DNA analysis of prostatic cancer materials after hormone therapy also produces meaningful information in predicting the prognosis of prostatic cancer.

Protective action of dopamine against glutamate neurotoxicity in the retina

PURPOSE

The electrophysiologic study using patch-clamp techniques demonstrated that NMDA-induced currents had properties similar to those recorded in the brain.

METHODS

Primary cultures obtained from the fetal rat retina (gestation days 16 to 19) were used for the experiment. Immunocytochemical and electrophysiologic studies were done to identify the cultured cells. The neurotoxic effects of glutamate or N-methyl-D-aspartate (NMDA) on the retinal cultures were quantitatively assessed using the trypan blue exclusion method.

RESULTS

The immunocytochemical study revealed that the major component of the rat retinal cultures was neurons including amacrine cells. The electrophysiologic study using patch-clamp techniques demonstrated that exposure to NMDA-induced currents with properties characteristic of those recorded in the brain. Brief exposure of these neurons to glutamate or NMDA induced delayed cell death. Glutamate neurotoxicity was prevented by the application of dopamine and forskolin. The protective action of dopamine was antagonized by a D1 receptor antagonist (SCH 23390) but not by D2 receptor antagonists (domperidone and sulpiride). A D1 receptor agonist (SKF 38393) protected glutamate-induced neurotoxicity in a concentration-dependent manner, whereas a D2 receptor agonist (quinpirole) did not affect it.

CONCLUSIONS

These findings demonstrate that dopamine protects retinal neuronal cells against NMDA receptor-mediated glutamate neurotoxicity via D1 receptors.

Cerebral ischemic attack caused by postprandial hypotension

BACKGROUND

Food ingestion sometimes induces systemic hypotension (postprandial hypotension). Although the possibility of stroke occurring postprandially has been suggested, no cases have been reported until now.

CASE DESCRIPTION

A 78-year-old man experienced repeated transient ischemic attacks after almost every ingestion of food and showed orthostatic and postprandial hypotension. An angiogram revealed occlusion of his left carotid artery and stenosis of his right middle cerebral artery.

CONCLUSIONS

Postprandial as well as orthostatic hypotension can be a risk factor for stroke in patients with severe occlusive cerebrovascular disease.

[Advanced breast cancer with remarkable response to the combination therapy of mitoxantrone (MIT) and medroxyprogesteron acetate (MPA) after failure of anthracycline therapy: a case report]

A 67-year-old advanced breast cancer patient with multiple bone metastases showed a remarkable response to the combination therapy of mitoxantrone (MIT) and medroxyprogesteron acetate (MPA) after failure of anthracycline therapy. Eight course of CTF (cyclophosphamide, THP-adriamycin, 5-fluorouracil) and subsequent 4'-epi-adriamycin were performed for locally advanced breast cancer and multiple bone metastases, but the ulcerated breast cancer enlarged. Then the combination therapy of MIT (10 mg/day) and MPA (1,200 mg/day) was carried out. Seven months after treatment, the ulcerated breast cancer disappeared completely and the serum levels of CA 15-3, TPA and CEA decreased within the normal range. These results suggest that combination therapy with mitoxantrone may well be effective against the anthracycline-resistant breast cancer.

Sequence analysis of the proximal promoter region of the human alpha-fetoprotein gene in hepatocellular carcinoma

We have examined whether or not mutations exist in the proximal promoter region of the human alpha-fetoprotein (AFP) gene in the hepatocellular carcinoma (HCC) tissue. Genomic DNA was extracted from four patients: one HCC tissue, one HCC and its corresponding non-cancerous (cirrhosis) tissues, one liver cirrhosis (LC) tissue without HCC and one matching HCC tissue and peripheral blood leukocytes. Serum concentrations of AFP in the patients ranged from less than 5 to 10,138 ng/ml. Nucleotide sequence was determined by direct sequencing using a single-stranded DNA template that was produced first through the polymerase chain reaction (PCR) amplification and then asymmetric PCR. In one HCC tissue taken from the patient with a high concentration of serum AFP, nucleotides different from published ones were detected at -120 and -113. These changes, however, probably reflect a DNA polymorphism, because peripheral blood leukocytes of the same patient had the same changes. Including this patient, no mutations in the region from -160 to -10 were detected in the HCC specimens we have examined. These results suggest that the extremely proximal promoter region of the AFP gene where glucocorticoid-responsive element and HNF-1 binding sites exist is not responsible for the re-expression of AFP in HCC.

Interaction between clarithromycin and biofilms formed by Staphylococcus epidermidis

Interactions between clarithromycin and biofilms formed by Staphylococcus epidermidis were investigated by using a clarithromycin-resistant strain. Treatment of the colonization with a relatively low concentration of clarithromycin resulted in the eradication of slime-like structure and a decrease in the quantity of hexose. Another result was increased penetration of antibiotics through the biofilm of S. epidermidis.

[Pharmacokinetic and clinical studies with cefozopran in the pediatric field. Pediatric Study Group of Cefozopran]

We investigated pharmacokinetics and clinical effectiveness of a newly developed cephem antibiotic cefozopran (SCE-2787, CZOP) against various pediatric infections in 18 institutions and their affiliates. We obtained the following results. 1. Serum concentration and urinary excretion rates Pharmacokinetics of CZOP in children was examined after intravenous injection and 30-minute drip infusion of 10, 20 and 40 mg/kg of CZOP. Peak serum concentrations of CZOP in 30 minutes after intravenous injection were 21.7, 51.5 and 77.8 micrograms/ml, respectively, showing a clear dose response. Half-lives were 1.99, 1.85 and 1.67 hours, respectively. In the first 6 hours after administration, urinary excretion rates of CZOP were 87.3, 67.4 and 84.1%, respectively. In the cases of 10, 20 and 40 mg/kg administration of CZOP 30-minute drip infusion, peak serum concentration of CZOP in 30 minutes, when the infusion was completed, were 38.1, 72.8 and 95.6 micrograms/ml, respectively. Again, there was a clear dose response. Half-lives were 1.67, 1.69 and 1.43 hours, respectively. In the first 6 hours after administration, urinary excretion rates of CZOP were 53.9, 59.7 and 77.3%, respectively. Cerebrospinal fluid concentrations of CZOP administered by intravenous injection of 50 mg/kg to patients with purulent meningitis were 1.6 to 43.4 micrograms/ml in 1 to 1.5 hours after administration. 2. Clinical study Clinical efficacy was evaluated in 337 cases. The largest number of cases, 138 cases, were found in 2 to < 6-year olds. The majority of the patients were under age 9, and 70 cases were of less than 1-year old infants. 183 cases were males and 154 cases were females. In terms of illness, a majority, or 185 cases, suffered from pneumonia, followed by 39 cases of UTI and 23 infections of the skin and soft tissue. There were 7 cases of purulent meningitis. In 218 cases, CZOP was administered at a daily dose of 60- < 80 mg/kg. The drug was administered for 6-10 days, the most frequent duration, in 188 cases. In the cases where causative organisms were identified (group A), the efficacy rates ("excellent" and "good") obtained were 100% (5/5) against purulent meningitis, 100% (2/2) against sepsis, 98.3% (119/121) against pneumonia, 100% (13/13) against acute bronchitis, 100% (11/11) against upper respiratory tract infection, 96.3% (26/27) against UTI. Overall, "excellent" and "good" responses were observed in 97.5% (197/202) of cases with known causative organisms.(ABSTRACT TRUNCATED AT 400 WORDS)

Detection of coxsackie B4 virus RNA in infected mouse kidneys by in situ hybridization

We describe a method for detecting virus-specific RNA sequences using a nonradioactive enzyme system, and analyze coxsackie B4 virus (cox.B4) RNA sequences in infected mouse kidney with pathological changes. Diffuse mesangial proliferation was observed transiently 24 h after inoculation of cox.B4 virus in glomeruli. OCT-treated thin sections of the same tissue were hybridized in situ using a digoxigenin-labeled oligonucleotide probe. The strongest signal was observed in the mesangial sample. These findings suggest that the transient proliferative mesangial changes were caused by direct injury following virus infection without immune complex.

Bidirectional regulation of smooth muscle cell proliferation by IFN-gamma

We studied the effects of interferon gamma (IFN-gamma), a T-cell lymphokine, on the proliferation and chemotaxis of vascular smooth muscle cells (SMC). Recombinant human IFN-gamma dose-dependently inhibited the proliferation of SMC cultured in the presence of 20% fetal calf-serum. It also inhibited PDGF-induced chemotaxis of SMC. Similar concentrations of IFN-gamma induced DNA-synthesis of SMC cultured in mitogen-depleted medium for 5 days. The inhibition and the stimulation of SMC proliferation were accompanied by concomitant decrease and increase in the number of PDGF receptors. Our study indicated that IFN-gamma is a bidirectional regulator of SMC proliferation.

Conversion of G-protein specificity of insulin-like growth factor II/mannose 6-phosphate receptor by exchanging of a short region with beta-adrenergic receptor

The 14-residue peptide (peptide 14) corresponding to Arg2410-Lys2423 of the insulin-like growth factor II receptor (IGF-IIR) can activate the adenylate cyclase-inhibitor guanine nucleotide-binding protein Gi, and the 15-residue beta III-2 peptide Arg259-Lys273 of the beta 2-adrenergic receptor (beta 2AR) can activate the stimulatory protein Gs. In phospholipid vesicles, IGF-IIR and beta 2AR activate Gi and Gs in response to IGF-II and isoproterenol, respectively. We constructed a chimeric IGF-II receptor (beta III-2/IGF-IIR) by converting its native peptide 14 sequence to the beta III-2 sequence. In cells expressing beta III-2/IGF-IIR, membrane adenylate cyclase activity markedly increased without IGF-II and was further promoted by IGF-II. This was verified by measuring chloramphenicol acetyltransferase (CAT) activity in beta III-2/IGF-IIR cells with cotransfection of a cAMP response element-CAT construct. This study shows not only the conversion of G-protein specificity of a receptor from Gi to Gs but also the simulation of G protein-coupled receptor signals by using a short receptor region and intact cells. These findings indicate that the G protein-activation signals are interchangeable, self-determined structural motifs that function in the setting of either a single-spanning or multiple-spanning receptor.

Calcium control of actin-myosin-based contraction in Triton-treated murine bladder tumor cells

Using mouse bladder tumor cells (MBT-2 cells) and epithelial cells, the present study evaluated the functional characteristics of the actomyosin system in bladder cancer cells. An immunofluorescence study demonstrated the presence of contractile proteins (actin and myosin) in MBT-2 cells as well as bladder epithelial cells. Triton-treated MBT-2 cells and epithelial cells showed a Ca(2+)-dependent contraction. This was inhibited by N-ethylmaleimide-modified myosin subfragment 1 (NEM-S1), demonstrating that the interaction between actin and myosin is responsible for the contraction of Triton-treated cells. The extent of Ca(2+)-dependent contraction was much greater in MBT-2 cells than in epithelial cells. These results suggest that MBT-2 cells possess a locomotive apparatus consisting of actin and myosin, and that Ca2+ can activate this actomyosin system, leading to the contraction or active locomotory movement of tumor cells.

[Influence of S-1108 on intestinal bacterial flora]

The effect of S-1108, a new oral cephem antibiotic, on intestinal bacterial flora was studied in tetra-contaminated mice and pediatric patients. S-1108 in a fine granular form was administered at a dose of 15 mg/kg once a day for 5 consecutive days to mice infected with Escherichia coli, Enterococcus faecalis, Bacteroides fragilis and Bifidobacterium breve. The viable fecal bacterial cell count of each of these 4 species of bacteria was slightly reduced in 5 days after the start of the drug administration. Five boys (weighing 12.0 to 42.0 kg) with bacterial infections were entered into this pediatric study. Their ages ranged from 2 years 4 months to 9 years 3 months. S-1108 (fine granules) was administered at a dose of 2.3 to 6.0 mg/kg, 3 times a day for 5 to 11 days. Cell counts of primary aerobes, anaerobes and total anaerobic cells decreased markedly in three patients, but in the remaining two patients the total number of aerobic and anaerobic cells did not change appreciably. Glucose-nonfermentating Gram-negative rods did not become predominant during the period of S-1108 administration. Candida became predominant in the three patients in whom the other bacteria had markedly decreased. Counts of predominant aerobic and anaerobic bacteria decreased markedly during the regimen in 3 out of 5 cases. S-1006 was detected in stools of the 3 cases at concentrations ranging from 235 to 516 micrograms/g during the administration of S-1108. Intestinal bacteria that produce beta-lactamase were not present in the feces of any of the patients. Based on these results, S-1108 (fine granules) appears to have relatively little effect on intestinal bacterial flora similarly to other new oral cephems. Because of individual differences, however, the drug may be excreted in the feces at high concentrations, and this would result in changes in intestinal bacterial flora. Therefore, attention must be given to fecal drug concentrations.

cAMP activates the IL-5 promoter synergistically with phorbol ester through the signaling pathway involving protein kinase A in mouse thymoma line EL-4

Expression of the IL-5 gene in T cells is induced in response to Ag stimulation; however, functional analysis of the IL-5 gene has been limited by lack of an appropriate transfection assay to facilitate measurement of the IL-5 promoter activity in response to T cell activation signals. Here, we describe a transient transfection system with which the IL-5 promoter activity can be assayed quantitatively. Using mouse thymoma line EL-4 cells, which produce several lymphokines including IL-2, IL-3, IL-4, IL-10, and GM-CSF in response to PMA, the effect of cAMP on IL-5 production was examined. These cells produce a low level of IL-5 when stimulated with PMA alone; however, N6, O2-dibutyryl cAMP (Bt2cAMP), in combination with PMA, augmented by more than tenfold the IL-5 production at the mRNA and the protein levels. Likewise, a transient transfection assay revealed that Bt2cAMP activated the IL-5 promoter more than tenfold, in a PMA-dependent manner, thereby indicating that two signals, PMA and cAMP, are required for optimal activation of the IL-5 promoter. Activation of the IL-5 promoter in response to Bt2cAMP and PMA depends on the region spanning from nucleotide position -1,200 to +33 relative to the transcription initiation site. Action of cAMP on the IL-5 promoter is mimicked by cotransfection of the expression plasmid containing cDNA encoding the catalytic subunit of protein kinase A, hence, cAMP probably exerts its action through the signaling pathway that involves protein kinase A. In contrast, Bt2cAMP almost completely inhibited the PMA-dependent activation of the endogenous IL-2 gene as well as the transfected IL-2 promoter. These results indicate that the IL-5 gene in EL-4 cells is positively regulated by cAMP in a manner opposite that for the IL-2 gene.

Structural study of the sugar chains of porcine factor VIII--tissue- and species-specific glycosylation of factor VIII

The asparagine-linked sugar chains of blood coagulation factor VIII purified from porcine plasma were released as oligosaccharides by hydrazinolysis. These sugar chains were converted to radioactive oligosaccharides by reduction with sodium borotritide and separated into neutral and acidic fractions by paper electrophoresis. Most of the acidic oligosaccharides were converted to neutral ones by sialidase digestion, indicating that they are sialyl derivatives. The neutral and the sialidase-treated acidic oligosaccharides were fractionated by serial chromatography on immobilized lectin columns. Structural study of each oligosaccharide by sequential exoglycosidase digestion and by methylation analysis revealed that porcine factor VIII contains high mannose-type and bi-, tri-, and tetraantennary complex-type sugar chains. Sixty-seven percent of the complex-type sugar chains contained the Gal alpha 1-->3Gal group, and 23% of the biantennary complex-type sugar chains contained the bisecting N-acetylglucosamine residue. These structures were not detected in the sugar chains of human plasma factor VIII. An in vitro competition study of von Willebrand factor and anti-Gal antibody for binding to factor VIII revealed that von Willebrand factor prevented antibody binding to Gal alpha 1-->3Gal groups in porcine factor VIII sugar chains. This suggests that anti-Gal antibody present in human plasma may not interact with the sugar chains of therapeutic porcine factor VIII. Reverse-transcription polymerase chain reaction was used to identify porcine tissues producing FVIII mRNA. These studies revealed that the kidney is one of the major tissues expressing factor VIII which may contain the sugar chains with the bisecting N-acetylglucosamine residue.

Action myoclonus induced by visually guided movement

In order to determine what kind of voluntary movement induces action myoclonus, we gave two siblings with sialidosis two kinds of tasks. When the patients were asked to move their index fingers following a smoothly moving target, action myoclonus became prominent. In contrast, when they were asked to perform the same movements with their eyes closed, they could move their index fingers very smoothly. This shows that action myoclonus was induced by visually guided movement, but not by self-paced movement. Our observations might reflect a disorder of the cerebellum, which controls visually guided movement.

cAMP activates the IL-5 promoter synergistically with phorbol ester through the signaling pathway involving protein kinase A in mouse thymoma line EL-4

Expression of the IL-5 gene in T cells is induced in response to Ag stimulation; however, functional analysis of the IL-5 gene has been limited by lack of an appropriate transfection assay to facilitate measurement of the IL-5 promoter activity in response to T cell activation signals. Here, we describe a transient transfection system with which the IL-5 promoter activity can be assayed quantitatively. Using mouse thymoma line EL-4 cells, which produce several lymphokines including IL-2, IL-3, IL-4, IL-10, and GM-CSF in response to PMA, the effect of cAMP on IL-5 production was examined. These cells produce a low level of IL-5 when stimulated with PMA alone; however, N6, O2-dibutyryl cAMP (Bt2cAMP), in combination with PMA, augmented by more than tenfold the IL-5 production at the mRNA and the protein levels. Likewise, a transient transfection assay revealed that Bt2cAMP activated the IL-5 promoter more than tenfold, in a PMA-dependent manner, thereby indicating that two signals, PMA and cAMP, are required for optimal activation of the IL-5 promoter. Activation of the IL-5 promoter in response to Bt2cAMP and PMA depends on the region spanning from nucleotide position -1,200 to +33 relative to the transcription initiation site. Action of cAMP on the IL-5 promoter is mimicked by cotransfection of the expression plasmid containing cDNA encoding the catalytic subunit of protein kinase A, hence, cAMP probably exerts its action through the signaling pathway that involves protein kinase A. In contrast, Bt2cAMP almost completely inhibited the PMA-dependent activation of the endogenous IL-2 gene as well as the transfected IL-2 promoter. These results indicate that the IL-5 gene in EL-4 cells is positively regulated by cAMP in a manner opposite that for the IL-2 gene.

[Laboratory and clinical studies on S-1108 in the pediatric field]

Laboratory and Clinical Studies on S-1108, a new oral cephem antibiotic, were carried out to evaluate its usefulness at a dose between 2 and 4 mg/kg a day for 7 to 14 days in the pediatric field. 1) Pharmacokinetic studies S-1108 at a dose of 2 mg/kg was administered to evaluate the pharmacokinetic parameters in 1 subject. Cmax, T1/2 and AUC were 0.69 hour, 1.42 hours and 2.15 micrograms.hr/ml, respectively. 2) Antimicrobial activities MICs against various clinically isolated organisms (Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, Branhamella catarrhalis, Escherichia coli and Haemophilus influenzae) were determined. The MIC values of S-1006 were similar to those of cefteram, the MICs against S. pyogenes, and H. influenzae were < or = 0.025 and 0.10 microgram/ml, respectively. 3) Clinical studies S-1108 was administered to patients with various pediatrics infections in 34 cases (upper respiratory tract infections: 12 cases, lower respiratory tract infections: 5 cases, urinary tract infections: 9 cases, skin and soft tissue infection: 6 cases, otitis media: 2 cases). Clinical efficacy rate was evaluated according to "Standard of clinical evaluation in pediatrics field". The responses were all good or excellent. 4) Side reactions There were no serious adverse reactions in any cases. The above results suggest that S-1108 is potent effective and safe agent in the pediatric field at a dose between 2-4 mg/kg (t.i.d.) a day.

[Rapid improvement of nerve conduction in a patient with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)]

A patient with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) underwent electrophysiological examinations before and three days after high-dose intravenous gamma-globulin therapy. In only three days, the distal latency and MCV of the right median nerve were markedly improved without change of amplitude or configuration of CMAP. Such rapid improvement in conduction velocity might not be due to remyelination, because it occurred in only three days. During recovery from conduction block after lidocaine administration in normal subjects, the distal latency was shortened without the change of its amplitude and configuration. This phenomenon is similar to the improvement in the distal latency of the right median nerve of this patient after high-dose intravenous gamma-globulin therapy. We assume, therefore, that the conduction slowing in CIDP should be attributed to inactivation of sodium channels as well as demyelination.

Differential regulation of early response genes and cell proliferation through the human granulocyte macrophage colony-stimulating factor receptor: selective activation of the c-fos promoter by genistein

Granulocyte macrophage colony-stimulating factor (GM-CSF) binds to the high-affinity GM-CSF receptor (GMR) consisting of alpha and beta subunits and induces rapid tyrosine phosphorylation, activation of early response genes, and proliferation of hematopoietic cells. The alpha subunit is the primary cytokine binding component and the beta subunit is required for high-affinity binding as well as for signal transduction. Using tyrosine kinase inhibitors and cytoplasmic deletion mutants of the beta subunit, we obtained evidence that there are at least two distinct pathways downstream of the GMR in BA/F3 cell, one which is essential for proliferation, leads to the c-myc gene activation, and is sensitive to herbimycin and genistein. Activation of this pathway depends on the cytoplasmic region between amino acid positions 455 and 517 of the beta subunit. The second pathway, which leads to activation of c-fos and c-jun genes, is only partially sensitive to herbimycin, is resistant to genistein and depends on the region between amino acid positions 626 and 763 of the beta subunit. Unexpectedly, the c-fos mRNA induction was augmented by genistein. The enhanced expression of c-fos mRNA by genistein also occurred with stimulation with cAMP, PMA, or EGF in NIH3T3 cells. It thus seems likely that genistein affects a common pathway downstream of these signals.