The Hcr (hepatocarcinogen resistance) loci of DBA/2J mice partially suppress phenotypic expression of the Hcs (hepatocarcinogen sensitivity) loci of C3H/HeJ mice

Both male DBA/2J and C3H/HeJ mice are highly susceptible to hepatocarcinogenesis induced by experimental treatment with N,N-diethylnitrosamine (DEN) relative to male C57BL/6J mice. While C3H/HeJ mice carry multiple sensitivity loci, designated Hcs (hepatocarcinogen sensitivity), our previous study indicated that the susceptibility of DBA/2J mice results from the combined effects of multiple sensitivity loci and two major resistance loci, Hcr-1 and -2 (hepatocarcinogen resistance). We proposed that BXD-15 recombinant inbred mice, which are extremely resistant to DEN-induced hepatocarcinogenesis, may carry the Hcr loci from the parental DBA/2J mice, but few, if any, of the multiple sensitivity loci. Conversely, the extremely sensitive BXD-11 recombinant inbred mice may carry most of the multiple sensitivity loci of the DBA/2J parents, but neither of the major resistance loci. In order to confirm our genetic model for hepatocarcinogenesis in DBA/2J mice and to evaluate the phenotypic effects of the Hcr loci on the Hcs loci of C3H/HeJ mice, we characterized hepatocarcinogen sensitivities of F1 mice generated from the crosses involving BXD-11, BXD-15, C3H/HeJ and C57BL/6J strains. When male mice were initiated with DEN at 12 days of age and liver tumors were enumerated at 32 weeks of age, (BXD-15 x BXD-11)F1 mice had one sixth the number of liver tumors observed in (C57BL/6J x BXD-11)F1 mice, consistent with our previous conclusion that DBA/2J mice possess hepatocarcinogen resistance genes in spite of their high susceptibility to DEN. Significantly, (C57BL/6J x C3H/HeJ)F1 mice also had a 2.3-fold greater number of liver tumors and 5.5-fold higher total volume of initiated lesions per liver as compared with (BXD-15 x C3H/HeJ)F1 mice, indicating that the hepatocarcinogen resistance genes inherited by BXD-15 mice are capable of suppressing the Hcs phenotype. Thus the Hcr loci may influence a wide variety of hepatocarcinogen sensitivity loci and be able to act as general resistance loci for chemical hepatocarcinogenesis. Stereological analysis of initiated hepatocellular lesions with glucose 6-phosphatase deficiency revealed that the resistance genes largely influence the promotion stage of hepatocarcinogenesis.

Increased expression in adipocytes of ob RNA in mice with lesions of the hypothalamus and with mutations at the db locus

The gene product of the recently cloned mouse obese gene (ob) is important in regulating adipose tissue mass. ob RNA is expressed specifically by mouse adipocytes in vivo in each of several different fat cell depots, including brown fat. ob RNA is also expressed in cultured 3T3-442A preadipocyte cells that have been induced to differentiate. Mice with lesions of the hypothalamus, as well as mice mutant at the db locus, express a 20-fold higher level of ob RNA in adipose tissue. These data suggest that both the db gene and the hypothalamus are downstream of the ob gene in the pathway that regulates adipose tissue mass and are consistent with previous experiments suggesting that the db locus encodes the ob receptor. In db/db and lesioned mice, quantitative differences in expression level of ob RNA correlated with adipocyte lipid content. The molecules that regulate expression level of the ob gene in adipocytes probably are important in determining body weight, as are the molecules that mediate the effects of ob at its site of action.

Identification of hepatocarcinogen-resistance genes in DBA/2 mice

Male DBA/2J mice are approximately 20-fold more susceptible than male C57BL/6J mice to hepatocarcinogenesis induced by perinatal treatment with N,N-diethylnitrosamine (DEN). In order to elucidate the genetic control of hepatocarcinogenesis in DBA/2J mice, male BXD recombinant inbred, D2B6F1 x B6 backcross, and D2B6F2 intercross mice were treated at 12 days of age with DEN and liver tumors were enumerated at 32 weeks. Interestingly, the distribution of mean tumor multiplicities among BXD recombinant inbred strains indicated that hepatocarcinogen-sensitive DBA/2 mice carry multiple genes with opposing effects on the susceptibility to liver tumor induction. By analyzing D2B6F1 x B6 backcross and D2B6F2 intercross mice for their liver tumor multiplicity phenotypes and for their genotypes at simple sequence repeat marker loci, we mapped two resistance genes carried by DBA/2J mice, designated Hcr1 and -2, to chromosomes 4 and 10, respectively. Hcr1 and Hcr2 resolved the genetic variance in the backcross population well, indicating that these resistance loci are the major determinants of the variance in the backcross population. Although our collection of 100 simple sequence repeat markers allowed linkage analysis for approximately 95% of the genome, we failed to map any sensitivity alleles for DBA/2J mice. Thus, it is likely that the susceptibility of DBA/2J mice is the consequence of the combined effects of multiple sensitivity loci.

CT imaging of abdominal hernias

Most abdominal hernias can be diagnosed on the basis of findings on physical examination or plain films and barium studies. However, diagnostic dilemmas can arise when patients are obese or have had surgery. Cross-sectional CT scans can show hernias and the contents of the peritoneal sac. More important, CT findings can be used to diagnose unsuspected hernias and to distinguish hernias from masses of the abdominal wall, such as tumors, hematomas, abscesses, undescended testes, and aneurysms. This essay illustrates the CT findings in diaphragmatic hernias, internal hernias, and abdominal wall hernias.

Hepatocyte growth factor transforms immortalized mouse liver epithelial cells

Transforming activity of hepatocyte growth factor (HGF) was demonstrated utilizing immortalized but not fully transformed mouse hepatocytes (MLE-10). Rat HGF cDNA, expressed under the control of a cytomegalovirus promoter, was transfected together with the neomycin resistance gene (PSV2neo) into MLE-10 cells by the calcium phosphate method, and propagated G418-resistant colonies were harvested colony by colony. After checking for integration and expression of exogenous HGF, five cell lines (MLE-10-HGF-1-5) were established. Three cell lines transfected with the vector only (MLE-10-CMV-1-3) were also established in the same manner. All MLE-10-HGF cell lines grew much faster than the MLE-10-CMV and original MLE-10 cells in culture and produced large colonies in soft agar, which colony production was blocked by the addition of anti-HGF antibody to the agar. After addition of HGF, original and MLE-10-CMV lines produced colonies in soft agar. The high-HGF-production lines (MLE-10-HGF-4 and -5) also gave rise to tumors within 2 weeks when implanted into the nude mice subcutis. In contrast, all MLE-10-CMV and original MLE-10 cells were negative in these growth assays. A rough parallelism between the level of HGF expression and the growth rate in both soft agar and nude mice subcutis was evident among MLE-10-HGF cell lines. Those with higher HGF production tended to grow in a scattered fashion in culture. High-affinity HGF receptor, HGFR/met, was expressed in MLE-10 and all the derived cell lines. Since HGF and/or HGFR/met gene expression is seen in various tumors and the serum HGF level is elevated in patients with hepatic disease, the present results indicate a possible significance of HGF and its receptor system in carcinogenesis, most probably via autocrine and/or paracrine mechanisms.

Hemovac drainage after hip arthroplasty

The authors have reviewed the pattern of drainage of Hemovac devices in 107 arthroplasties of the hip. Drainage ceased in 55 hips (51%) within 18 hours and 93 hips (89%) within 24 hours. The mean drainage volume was 303 cc in femoral head replacement, 498 cc in simple total hip replacement, and 663 cc in extensive total hip replacement. Ninety nine per cent of the total drainage had been achieved within 24 hours, indicating that drainage devices can be removed then rather than between 24 and 72 hours as had been previously recommended. This early removal will help reduce the possibility of retrograde infection, and promote more comfortable rehabilitation after operation.

Peripheral neuropathy as a hypereosinophilic syndrome and anti-GM1 antibodies

The acute peripheral neuropathy as one of hypereosinophilic syndrome is known to be a rare disorder. The authors experienced a dramatic case with acute peripheral neuropathy, hypereosinophilia in peripheral blood, and the positive anti-GM1 antibodies. The serum protein electrophoresis showed a diffusely increased gamma-globulin region and the polyclonal gammopathy was found by the immunoelectropheresis. There was no evidence of inflammatory myopathy in vastus lateralis muscle. The sural nerve biopsy was compatible with vascular neuropathy, as there were a few myelin digestion chambers, mild perineuronal fibrosis, and perivascular lymphoplasmocytic infiltration with focal organizing thrombosis. The clinical response to prednisone therapy was excellent.

Malignant transformation of a mouse liver epithelial cell line by transfection of an activated c-H-ras gene with a point mutation at codon 12

In order to scrutinize the reason why in mouse liver system only activated H-ras gene with a point mutation at codon 61 but not codon 12 is frequently seen although the latter mutation is highly frequent in methylnitrosourea-induced rat mammary tumors, transforming activity of these two types of mutated H-ras gene was investigated utilizing an immortalized but not fully transformed mouse liver epithelial cell line MLE-10, established in our laboratory. MLE-10 cells were transfected with activated human c-H-ras gene having a point mutation at either codon 12 (PT24) or 61 (PSK2), together with PSV2neo, or with PSV2neo only. G418 resistant colonies, propagated separately, gave rise to 6, 3 and 6 lines respectively. All the PT24 and PSK2-transfected cell lines were growth capable in both soft agar and nude mouse subcutis, with similar growth rate and morphological features whereas none of the cell lines transfected with the PSV2neo only revealed such growth capability. The results thus revealed that c-H-ras with a mutation at codon 12 has oncogenic activity to the mouse hepatocyte, although after immortalization, at the degree similar to the same gene with a mutation at codon 61.

Development of liver tumors in transforming growth factor alpha transgenic mice

We studied the development of liver tumors in male transforming growth factor alpha (TGF-alpha) transgenic mice of the CD1 strain and examined the expression of the transgene by immunohistochemistry and in situ hybridization. Livers of 4-5-week-old transgenic mice contained areas of centribobular hypertrophy with low glucose-6-phosphatase activity. These areas progressively expanded, and hypertrophy and dysplasia became generalized in livers of mice at 10-12 months of age. The expression of the transgene, determined by either immunohistochemistry or in situ hybridization, was uneven in animals that were 10 weeks old or older. The positive hepatocytes formed patches with a predominant centrilobular distribution. We studied a total of 23 liver tumors (7 hepatocellular carcinomas and 16 adenomas) obtained from 11 mice at 13-15 months of age and from one 7-month-old animal which received zinc sulfate to induce the transgene. The carcinomas were well differentiated tumors, without glucose-6-phosphatase or gamma-glutamyltranspeptidase activity, that developed from the dysplastic parenchyma and occasionally within an adenoma. In all carcinomas and in 56% of the adenomas there was overexpression of the transgene in relationship to the surrounding tissue. The majority of the tumors that overexpressed TGF-alpha were alpha-fetoprotein positive, while alpha-fetoprotein staining was not detected in tumors (all adenomas) that did not show excessive transgene expression. We conclude that TGF-alpha functions as a promoter of liver carcinogenesis through its effect as an autocrine inducer of hepatocyte proliferation. Further, the data indicate that TGF-alpha overexpression may favor tumor progression.

A cytoplasmic chaperonin that catalyzes beta-actin folding

We have isolated a cytoplasmic chaperonin based on its ability to catalyze the folding of denatured beta-actin. The cytoplasmic chaperonin is organized as a multisubunit toroid and requires Mg2+ and ATP for activity. The folding reaction proceeds via the rapid ATP-independent formation of a binary complex, followed by a slower ATP-dependent release of the native product. Electron microscopic observations reveal a striking structural change that occurs upon addition of Mg2+ and ATP. The eukaryotic cytoplasm thus contains a chaperonin that is functionally analagous to its prokaryotic, mitochondrial, and chloroplastic counterparts.

Strain specific sensitivity to diethylnitrosamine-induced carcinogenesis is maintained in hepatocytes of C3H/HeN in equilibrium with C57BL/6N chimeric mice

The C3H/HeN (C3H) and C57BL/6N (C57) mouse strains are known, respectively, for their high and low susceptibility to both spontaneous and chemically induced hepatocarcinogenesis. The present study was aimed at elucidating whether this difference is dependent on intrinsic features of the target hepatocytes or in the in vivo milieu and associated growth promoting factors to which the cells are exposed. C3H in equilibrium with C57 chimeric mice were produced and given injections of diethylnitrosamine (20 microgram/g body weight) at the age of 15 days. The animals were sacrificed 6 or 9 months thereafter, and the numbers and sizes of altered cell lesions were scored. The clonal growth of both cell types was immunohistochemically confirmed using anti C3H-specific antigen antibodies. Quantitative assessment revealed C3H lesions in the chimera livers to be far larger (5:1) than those of C57 derivation and associated with more frequent malignant progression as was evident histologically. Furthermore, foamy change and hyalin body formation, which have been described as characteristics of C3H and C57BL hepatic tumors, respectively, were also featured as differentiative characteristics in lesions of both cell types in chimera mice. Thus, the results clearly demonstrated that the principal mechanism(s) underlying strain difference in diethylnitrosamine-initiated hepatocarcinogenesis exists in the target cells and is not milieu-dependent.

Alpha-fetoprotein-producing papillary adenocarcinoma originating from a uterine body. A case report

A rare case of alpha-fetoprotein (AFP)-producing papillary adenocarcinoma originating from the uterine body of a 55-year-old Japanese woman is reported. The histologic appearance of the tumor was reminiscent of a serous papillary carcinoma of the ovary, in clear contrast to that of common endometrial adenocarcinomas. No features of embryonal carcinoma or yolk sac tumor were evident. Immunohistochemical examination demonstrated the production of AFP by the tumor cells. To our knowledge there are six reported cases of AFP-producing malignant tumors of the uterine body in the literature, four of them being yolk sac tumor, one mixed mesodermal tumor, and one endometrial adenocarcinoma. This is therefore the first case of an AFP-producing papillary adenocarcinoma that developed in the uterine body. This report should contribute to a better understanding of the histogenesis of AFP-producing tumors in this organ.

Role of activated c-H-ras oncogene in the induction and progression of immortal liver epithelial cell lines derived from normal C3H mice

The nature of 15 immortal mouse liver epithelial cell (MLEC) lines established from normal C3H mice was investigated specifically in terms of ras oncogene activation. Neither transforming activity nor point mutation within codon 61 of c-H-ras could be demonstrated in any of the cell lines by DNA transfection in a NIH/3T3 cell system or by the direct sequencing method after polymerase chain reaction, respectively. Acrylamide gel migration analysis of ras p21 products did not show any shift from the normal. Transplantation experiments demonstrated only 2 out of the 15 lines to be tumorigenic in nude mice. When 4 of the non-tumorigenic MLEC lines were transfected with cloned activated c-H-ras containing a point mutation within codon 61, they all became tumorigenic, the resultant neoplasms being hepatocellular carcinomas often associated with albumin mRNA expression. Our results thus indicate that ras activation is not necessary for immortalization or even for transformation of mouse liver cells in culture, and that ras activation may be an event during the progression process in mouse hepatocarcinogenesis in vivo.

Low frequency of ras activation in 2-acetylaminofluorene- and 3'-methyl-4-(dimethylamino)azobenzene-induced rat hepatocellular carcinomas

Activation of ras protooncogenes in 11 2-acetylaminofluorene (AAF)-induced hepatocellular carcinomas (HCCs) or liver cell lines and 9 3'-methyl-(dimethylamino)azobenzene (3'-Me-DAB)-induced HCCs in rats was examined using the NIH3T3 cell transfection assay and oligonucleotide hybridization analysis. Only one cell line established from a AAF-treated rat liver demonstrated transforming activity with a point mutation and ATTA transversion at the second position of H-ras codon 61. The rates of ras activation were thus very low for both AAF- and 3'-Me-DAB-induced rat HCCs, the results thus extending and confirming the findings indicating that ras activation in rat HCCs induced by various type of carcinogens is infrequent.

In vitro progression-associated c-H-ras activation in neoplastic hepatocyte lines established from SV40-T antigen gene-harboring transgenic mice

In order to investigate the molecular mechanisms of multistep hepatocarcinogenesis in SV40-T antigen gene-harboring transgenic mice, 9 hepatocellular carcinoma (HCC) lines and 10 "preneoplastic" hepatocyte lines were established from the animals and their biological and molecular changes during culture were investigated. Three of the 9 HCC lines showed progression during culture in terms of growth rate and growth capability in soft agar and in nude mice. This progression was associated with the appearance of activated c-H-ras oncogene. Including these 3 lines, H-ras activation was observed in a total of 7 of the 9 HCC lines (78%), whereas it was found only in 1 of 10 (10%) "preneoplastic" hepatocyte lines. These data thus indicate that H-ras activation may be an event occurring at a relatively late stage of hepatocarcinogenesis in this transgenic mouse system and that it may serve towards completion of the carcinogenic process together with the T-antigen.

Detection of activated c-H-ras oncogene in hepatocellular carcinomas developing in transgenic mice harboring albumin promoter-regulated simian virus 40 gene

Hepatocellular carcinomas (HCCs) developing in transgenic mice harboring an albumin promoter-regulated simian virus 40 (SV40) tumor antigen gene were analyzed for activating point mutations of the c-H-ras oncogene. Oligonucleotide hybridization studies utilizing enzymatically amplified DNA sequences of paraffin-embedded tumor tissues revealed that 10 out of 25 HCCs contained either an A-to-T or an A-to-G conversion at the second position of codon 61. Northern blot studies confirmed expression of SV40 gene mRNAs in the tumor tissues of both mutation-positive and mutation-negative HCCs. These findings in association with earlier results thus strongly suggest that mutational activation of cellular oncogene may play an important role in SV40-initiated multistage hepatocarcinogenesis in vivo.

Comparative study of diethylnitrosamine-initiated two-stage hepatocarcinogenesis in C3H, C57BL and BALB mice promoted by various hepatopromoters

The comparative inducibility of enzyme-altered islands (EAIs) by diethylnitrosamine (DEN) and their responsiveness to hepatopromoters belonging to different classes were studied in C3H/HeN (C3H), C57BL/6N (C57) and BALB/cA (BALB) mice. Male mice were given an i.p. injection of DEN (20 micrograms/g body weight) after partial hepatectomy at 6 weeks of age and then fed either basal diet or diet containing phenobarbital (PB) (500 p.p.m.), clofibrate (CF) (1000 p.p.m.) or ethynyl estradiol (EE) (10 p.p.m.). The numbers and size distribution of EAIs were assessed after the mice were killed at week 20, utilizing stereological methods. In the groups receiving DEN but no promoter, the number and mean size of the lesions were far larger in the C3H mice than in the other strains. Under the promoting pressure of PB, the growth of EAIs in C3H and BALB were accelerated remarkably, but those of C57 mice only slightly. Interestingly, in BALB the number of EAIs was much fewer than those of C3H in spite of their good sensitivity to PB, suggesting that BALB was refractory to the initiation process by DEN. A promoting effect for CF could only be demonstrated for the C3H strain and EE as the dose used inhibited the development of EAIs in all the strains. The experimental data thus indicate that interstrain differences in two-stage hepatocarcinogenesis among mice with different genetical backgrounds may exist, either in initiation or promotion, or in both processes.

Organization of microtubules in dendrites and axons is determined by a short hydrophobic zipper in microtubule-associated proteins MAP2 and tau

Here we report that the microtubule-associated proteins MAP2 and tau share two separable functional domains. One is the microtubule-binding site which serves to nucleate microtubule assembly; the second is a short C-terminal alpha-helical sequence which can crosslink microtubules by means of a hydrophobic zipper interaction into dense stable parallel arrays characteristic of axons or dendrites. Thus, interactions between molecules of a single type are capable of drastically reorganizing microtubules and completely suppressing their dynamic properties.

[A study of chronic schizophrenic patients on the attention tests]

Three groups of people--schizophrenic (26 patients), affective disorder (23 patients), and normal (27 persons) were administered two attention tests--Tai Ta Attention Test and Kraepelin Test. The results indicate that the speed and duration of attention of schizophrenic patients are poorer than those of normal persons. And the attention deficit is not much different between the two psychotic group patients. This study finds that the main attention problem of schizophrenic patients is their deficit of duration of attention.

Desensitization of calcium mobilization and cell function in human neutrophils

Neutrophils pretreated with the chemoattractant formylmethionyl-leucyl-phenylalanine become unresponsive when re-exposed to the same ligand, a process termed desensitization. We have examined whether desensitization of transduction (Ca2+ mobilization) or of other cell functions (superoxide generation, enzyme release, or aggregation) occurs synchronously. Simultaneous studies of Ca2+ mobilization and aggregation by using Fura-2-loaded cells indicate that, under conditions where the aggregation response is abolished, most of the Ca2+ mobilization is unaltered. Further studies were then carried out to ascertain whether desensitization of Ca2+ mobilization could in fact be induced. Desensitization was observed, and was dependent on the number of exposures of the cells to the ligand, the concentration of the ligand, and whether the ligand was left in the medium or was removed. The pattern of resensitization was dependent on the experimental design. Under conditions where ligand was continuously present, no recovery of the Ca2+-mobilization response was seen with subsequent challenges. In contrast, on removal of ligand, this response showed partial recovery. Whereas complete desensitization of aggregation was noted, enzyme release showed a markedly lesser degree of desensitization and required more frequent exposures to the ligand before it was observed. Little or no desensitization of superoxide generation was observed regardless of the conditions utilized. Studies using phorbol myristate acetate as the ligand showed that Ca2+ mobilization and aggregation could be simultaneously inhibited. Our results suggest that discrete mechanisms of desensitization are possible in human neutrophils, and that desensitization of one particular function (aggregation) does not imply concomitant desensitization of other functions.

Immortal epithelial cells of normal C3H mouse liver in culture: possible precursor populations for spontaneous hepatocellular carcinoma

Long-term culture of primary hepatocytes derived from normal young male C3H/HeNJclMTV+ (C3H) and C57BL/6NJcl (C57) mice, respectively known for very high and low incidences of spontaneous hepatoma, resulted in development of multiple slowly growing epithelial colonies in the C3H case, the number of colonies being increased five-fold when 1.5 mM phenobarbital was added to the culture medium. On the other hand, the primary culture cells from C57 mouse liver gave rise to such epithelial colonies only very rarely, even with phenobarbital. Immunohistochemical investigation revealed alpha-fetoprotein and/or albumin production by the colony cells and ultrastructural analysis also revealed some hepatocytic features in them. Subculturing of individual colonies gave rise to cell lines which could be repeatedly passaged. Two of five lines implanted into athymic nude mice manifested tumorigenicity, the resultant neoplasms being diagnosed as a trabecular hepatocellular carcinoma and an adenocarcinoma. The experimental data suggest that the colony-forming immortal epithelial cells possibly represent early phase precursors of spontaneous mouse hepatocellular carcinomas. This culture system is expected to be useful for future elucidation of the mechanisms underlying spontaneous mouse hepatocarcinogenesis.

Anti-immunoglobulin pretreatment induces a calcium-mobilization response to the chemotactic agent N-formylmethionylleucylphenylalanine in Daudi lymphoblastoid cells

Anti-immunoglobulin treatment of fura-2-loaded Daudi cells induces a calcium mobilization as judged by the increase in the fluorescence of the dye fura-2, AM. No calcium mobilization by N-fMet-Leu-Phe is observed in these cells. However, exposure of the cells to N-fMet-Leu-Phe after the first hit with anti-immunoglobulin (but not after soluble IgG) shows a rapid, dose-dependent calcium mobilization by N-fMet-Leu-Phe. The expression of the calcium-mobilizing response occurs in less than 2 min and is stable. Binding of tritiated N-fMet-Leu-Phe is increased in anti-immunoglobulin-treated but not control cells. The induction is specific for N-fMet-Leu-Phe because the chemoattractant platelet-activating factor did not induce any calcium mobilization. The N-fMet-Leu-Phe antagonist t-butoxycarbonyl-L-Phe-D-Leu-L-Phe-D-Leu-L-Phe- OH did not show any calcium mobilization on its own, either before or after anti-immunoglobulin treatment, and inhibited the calcium mobilization of N-fMet-Leu-Phe at low concentrations. Treatment of the cells with phorbol 12-myristate 13-acetate or pertussis toxin prior to anti-immunoglobulin treatment caused a dose-dependent abolition of both the anti-immunoglobulin-mediated calcium mobilization and the subsequent calcium mobilization by N-fMet-Leu-Phe. Metabolic inhibitors that act predominantly by lowering the ATP levels within the cell (iodoacetate, sodium fluoride, oligomycin, and 2-deoxyglucose) all produced a greater inhibition of the N-fMet-Leu-Phe-mediated calcium mobilization than the anti-immunoglobulin-mediated response. Lowering the temperature from 37 degrees C to 22 degrees C reduced the anti-immunoglobulin response and completely inhibited the expression of the N-fMet-Leu-Phe effect. Our results indicate that activation of the calcium-mobilization pathway in B cells by crosslinking of bound surface immunoglobulin causes an induction of N-fMet-Leu-Phe-sensitive calcium mobilization.