A candidate case for lymphocytic infundibulo-neurohypophysitis mimicking a neurohypophysial tumor

A 56-year-old Japanese man presented with a 2-month duration of polyuria and polydipsia. The diagnosis of diabetes insipidus was confirmed by water deprivation and vasopressin injection. The secretory function of the adenohypophysis was estimated as normal by a variety of provocative tests. Magnetic resonance imaging (MRI) displayed the loss of the hyperintense signal of the neurohypophysis and a tumor-like lesion confined to the neurohypophysis. The tissue specimen resected at transsphenoidal surgery showed diffuse lymphocytic infiltration. These findings suggest that this is a candidate case for lymphocytic infundibuloneurohypophysitis (LIN) that is not identical to classical lymphocytic hypophysitis. This patient will be followed up to determine whether this case simply represents an early stage of classical hypophysitis or a different clinical entity.

Quadrupolar nutation NMR on a compound semiconductor gallium-arsenide

Lattice defects in a compound semiconductor, gallium-arsenide are evaluated by two-dimensional nutation nuclear magnetic resonance. Especially in the case of indium doped gallium-arsenide, analysis of the nutation patterns indicates that the electric field gradient exists in the whole crystal. Asymmetry parameters and quadrupolar coupling constants are determined as approximately 1.0 and 93 kHz, respectively. These results suggest that the whole crystal is under slight strain. Through this work, it is demonstrated that a two-dimensional nutation nuclear magnetic resonance is the useful method to investigate the lattice defects in gallium-arsenide.

Immunohistochemical localization of extracellular matrix components in human breast tumours with special reference to PG-M/versican

Immunohistochemical localization of the large proteoglycan, PG-M/versican, was studied in 36 breast tumours, including infiltrating ductal carcinomas, benign tumours and fibrocystic diseases. The relation between the proteoglycan and the other extracellular matrix components was also investigated. In the carcinoma tissues, the interstitial elements of the 'specific stroma', consisting of fibroblastic cells and fine fibrils, were reactive to antibody 2B1, which specifically recognizes the large proteoglycan, PG-M/versican. In the peripheral invasive areas of infiltrating ductal carcinoma, the most intense 2B1-positive reaction was visualized in mesenchymal tissues between carcinoma cells clumps and the surrounding tissues, where hyaluronic acid could be demonstrated histochemically. The 2B1-positive elements were not reactive to antibody 6B6, which specifically recognizes small proteoglycan. In the central sclerotic areas, where antibody 6B6 was reactive, a 2B1-positive reaction was detected only in elastosis masses, which also bound antibodies to type IV collagen and laminin, and to some extent antibody raised against chondroitin 6-sulphate proteoglycan. Elastic tissues of blood vessel walls and perivascular elements became reactive to antibody 2B1 when they were involved in carcinoma invasion. The present results have shown that PG-M/versican was localized in the proliferating interstitial tissues, in particular in hyaluronic acid-rich portions, in association with carcinoma cell growth, and also that PG-M/versican accumulated in vascular and perivascular elastic tissues involved in carcinoma invasion. The biological significance of PG-M/versican was briefly discussed.

Induction of apoptosis in multi-drug resistant (MDR) human glioblastoma cells by SN-38, a metabolite of the camptothecin derivative CPT-11

The overexpression of the multidrug resistance (mdr1) gene and its product, P-glycoprotein (P-gp), is thought to limit the successful chemotherapy of human tumors. Recent studies demonstrate that SN-38, a metabolite of the camptothecin (CPT) derivative CPT-11, has antitumor effects on several tumors, but the mechanisms responsible for its cytotoxicity remain unclear. We therefore determined whether SN-38 has cytotoxic effects on MDR human glioblastoma GB-1 cells and non-MDR human glioblastoma U87-MG cells. Furthermore, we determined what role SN-38 plays in the induction of cytotoxicity in these tumor cells. In this study, we demonstrated that SN-38 had significantly stronger antitumor effects on GB-1 and U-87MG cells than did CPT (P < 0.01 and P < 0.05, respectively). In addition, findings obtained using a DNA fragmentation assay, Hoechst 33258 staining, in situ end-labeling and cell cycle analysis demonstrated that SN-38 induced apoptosis in these tumors. Our results suggest that SN-38 has a stronger antitumor effect on malignant glioma cells regardless of MDR expression than does CPT, and therefore can be considered a new chemotherapeutic agent potentially effective in the treatment of human primary or recurrent malignant gliomas resistant to chemotherapy.

Characteristics of temporal lobe epilepsy with mesial temporal sclerosis, with special reference to psychotic episodes

This study investigates the histories and the clinical course of 111 patients who had nonlesional temporal lobe epilepsy. We compared 61 patients with unilateral hippocampal sclerosis (UHS group) and 50 patients with minimal change (MRI negative group) assessed on the basis of MRI. In agreement with previous reports, we confirmed statistically that patients in the UHS group strongly tended to have had febrile convulsive status during early childhood or infancy and that habitual seizures tended to begin at a younger age than the other subset of nonlesional temporal lobe epilepsy. Strikingly, episodes of psychoses, especially postictal psychoses, occurred significantly more often in the UHS group than in the MRI negative group. Additional involvement of temporal neocortex further augmented this association. We stress the role of mesial temporal pathology, and its linkage to the temporal neocortex, in the genesis of postictal psychoses.

The transforming activities of MDM2 in cultured neonatal rat astrocytes

Although the molecular events regulating the pathogenesis of malignant astrocytomas remains unclear, the inactivation of tumor suppressor genes may be a key factor. The inactivation of p53 by mutation or deletion, however, is not the only obligatory step in astrocytoma genesis. The MDM2 protein has been shown to bind to and downmodulate p53 function, and to have oncogenic capacity. The MDM2 gene is also amplified and overexpressed in a subset of malignant astrocytomas without p53 mutation. Here we show that overexpression of MDM2 promoted the DNA synthesis of cultured neonatal rat astrocytes (RNB cells), abrogated the transcriptional activity of wild-type p53, conferred invasive activity, and subsequently induced the transformation from astrocytes to high-grade astrocytomas. Intriguingly, MDM2 enhanced the expression of angiogenic mitogens; basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF) in RNB cells. These results indicate that MDM2 may play an important role in the progression of astrocytomas, by not only conferring invasive activity but also stimulating the expression of angiogenic growth factors.

mdm2 gene mediates the expression of mdr1 gene and P-glycoprotein in a human glioblastoma cell line

The overexpression of the multidrug resistance (mdr1) gene and its product, P-glycoprotein (P-gp), is thought to limit the successful chemotherapy of human tumours. The mechanism by which mdr1 gene and P-gp are overexpressed in human tumours, however, is not yet clear. In this report, we show that the mdm2 (murine double minute 2) gene induced the expression of the mdr1 gene and P-gp in human glioblastoma U87-MG cells, which did not express the MDM2 protein or P-gp. The mdm2 gene, in addition, conferred the resistance of U87-MG cells to the apoptotic cell death induced by etoposide (VP-16) or doxorubicin. Furthermore, treatment with mdm2 antisense oligonucleotides inhibited the expression of P-gp in MDM2-expressing U87-MG cells. These findings suggest that the mdm2 gene may play an important role in the development of MDR phenotype in human tumours.

2B1 antigen characteristically expressed on extracellular matrices of human malignant tumors is a large chondroitin sulfate proteoglycan, PG-M/versican

2B1 is a monoclonal antibody against a large proteoglycan isolated from human yolk sac tumor (M. Sobue et al., Histochem. J., 21: 455-460, 1989). The antigen is expressed in a variety of embryonal tissues as well as most if not all malignant tumor tissues. However, the expression in normal adult tissues is limited to some tissues, such as the smooth muscle layers of the aorta. We characterized the 2B1 antigen isolated from the conditioned medium of human malignant fibrous histiocytoma and found that immunological and biochemical properties are identical to those of a large chondroitin sulfate proteoglycan, PG-M/versican. Partial amino acid sequences of peptides obtained from the core protein by V8 protease digestion and subsequent SDS-PAGE were detected in the reported amino acid sequence of human PG-M/versican with a complete identity. Furthermore, 2B1 was distinctly reactive to the expressed protein by transfection of the cDNA for the shortest form into mouse cells. The results indicate that the antigen is the PG-M core protein, and the epitope may be in one of the globular domains. It is thus likely that PG-M/versican is one of the extracellular matrix components characteristic of human malignant tumors.

Involvement of interleukin-1 beta-converting enzyme in apoptosis of bFGF-deprived murine aortic endothelial cells

Apoptosis (programmed cell death) is an essential physiological process that is genetically regulated and contributes to the balance between cell growth, differentiation, and the maintenance of normal cells. Recent studies show that deprivation of growth factor induces apoptosis in endothelial cells. However, the molecular mechanisms regulating apoptosis remain unclear. In this study, we demonstrate that deprivation of basic fibroblast growth factor (bFGF) increased the expression of interleukin-1 beta-converting enzyme (ICE) protein, and subsequently induced apoptosis in murine aortic endothelial (MAE) cells. In contrast, the proteins of the tumor suppressor p53 and c-myc were undetected during apoptosis. This apoptosis was suppressed by the tetrapeptide ICE inhibitor, Ac-YVAD-CMK. Overexpression of murine ICE, in addition, induced apoptosis in MAE cells using gene transfer techniques. These results strongly suggest that ICE may mediate apoptosis in bFGF-deprived endothelial cells, and the suppression of ICE function could represent a novel approach for the protection of endothelial cells from damages.-Kondo, S., Kondo, Y., Yin, D., Barnett, G. H., Kaakaji, R., Peterson, J. W., Morimura, T., Kubo, H., Takeuchi, J., Barna, B. P. Involvement of interleukin-1 beta converting enzyme in apoptosis of bFGF-deprived murine aortic endothelial cells.

A multicopy suppressor of nin1-1 of the yeast Saccharomyces cerevisiae is a counterpart of the Drosophila melanogaster diphenol oxidase A2 gene, Dox-A2

NIN1 is an essential gene for growth of the yeast Saccharomyces cerevisiae and was recently found to encode a component of the regulatory subunit of the 26S proteasome. The nin1-1 mutant is temperature sensitive and its main defect is in G1/S progression and G2/M progression at non-permissive temperatures. One of the two multicopy suppressors of nin1-1, SUN2 (SUppressor of Nin1-1), was found to encode a protein of 523 amino acids whose sequence is similar to those of Drosophila melanogaster diphenol oxidase A2 and the mouse mast-cell Tum(-) transplantation antigen, P91A. The C-terminal half of Sun2p was found to be functional as Sun2p at 25 degrees C, 30 degrees C, and 34 degrees C but not at 37 degrees C. The open reading frame (ORF) of the Drosophila diphenol oxidase A2 gene (Dox-A2) was obtained from a lambda phage cDNA library using the polymerase chain reaction technique. The Dox-A2 ORF driven by the TDH3 promoter complemented the phenotype of a strain deleted for sun2. This Dox-A2-dependent strain was temperature sensitive and accumulated dumb-bell-shaped cells, with an undivided nucleus at the isthmus, after temperature upshift. This morphology is similar to that of nin1-1 cells kept at a restrictive temperature. These results suggest that SUN2 is a functional counterpart of Dox-A2 and that these genes play a pivotal role in the cell cycle in each organism.

Tonsillar focal infection: clinical observations of low grade fever

Thirty patients (above 18 years) who had complained of low grade fever were diagnosed as having tonsillar focal infection. We performed tonsillectomies on all the patients. A total of 24 were cured and 6 patients improved after the operation. These results indicate that tonsillectomy is often an effective treatment for tonsillar focal infection. However, the provocation test did not always give a good result.

Interleukin-1 beta-converting enzyme mediates cisplatin-induced apoptosis in malignant glioma cells

Increasing the susceptibility of tumor cells to apoptotic cell death following chemotherapy is of importance to the outcome of cancer treatment. Although the tumor suppressor gene p53 is required for efficient induction of apoptosis by chemotherapeutic agents, it is not the only apoptosis mediator gene. The molecular mechanisms mediating apoptosis following chemotherapy via p53-dependent or p53-independent pathways remain unclear. We show here that cis-diamminedichloroplatinum (cisplatin) induces the expression of interleukin-1 beta-converting enzyme (ICE), a mammalian homologue of the Caenorhabditis elegans cell death gene ced-3, in murine and human malignant glioma cells during apoptosis regardless of their p53 status. Furthermore, overexpression of the murine ICE gene induces apoptosis in these tumor cells. The apoptosis induced by cisplatin treatment or murine ICE overexpression can be suppressed by the tetrapeptide ICE inhibitor Ac-YVAD-CMK or the apoptosis inhibitors bcl-2 or bcl-2-related bcl-XL gene. These findings suggest that ICE may mediate apoptosis induced by chemotherapy, and its induction could represent a novel approach for the effective treatment of malignant glioma.

[Natural interferon alpha for chronic myelogenous leukemia in the chronic phase: hematologic, cytogenetic and molecular response]

Twenty one patients with Philadelphia chromosome positive CML were treated with natural interferon alpha. All patients were in the chronic phase, 5 were untreated and 16 had been previously treated with busulfan or hydroxyurea. Eight patients in complete remission (CR) were given IFN subcutaneously at a dose of 5 x 10(6) unit per day as maintenance therapy, whereas 13 non-CR patients were given 2. 5 approximately 10 x 10(6) units for remission induction. Doses and intervals of IFN were adjusted to maintain the WBC count below 5 x 10(9)/l, but additional drugs were given when the WBC count could not be controlled with IFN alone. Six out of 10 evaluable non-CR patients attained CR with IFN only and 4 others achieved with additional drug. Cytogenetic responses were evaluated in 15 patients. CCR, PCR and MCR were attained in 5, 2 and 1 patients respectively. Southern blotting method showed that the BCR gene rearrangement disappeared in 5 out of 13 patients. Cytogenetic response rate was not different between untreated and previously treated patients, however it differed between patients with or without additional drug. The time to first cytogenetic effect was within 12 months in almost all effective cases. Fever and general fatigue were seen in almost all patients. IFN administration was discontinued only patients with severe skin eruption (3 patients) and bone marrow aplasia (1 patient).

[Structure and function of extracellular matrix with special references to proteoglycan]

To clarify the physiological significance of extracellular matrix components, biochemical and histochemical characterization of glycosaminoglycan and proteoglycan was performed. The glycosaminoglycan, chondroitin sulfate, was favorable to the growth of Ehrlich ascite tumor cells inoculated into the subcutaneous space of the mouse's back. The glycosaminoglycan content and its synthesis by gastric carcinoma tissue were compared with those of non-neoplastic mucosa, after incubation of tissue segments in medium containing 35SO4. The rate of glycosaminoglycan synthesis by medullary carcinoma tissue was much higher than that by the non-neoplastic mucosa, although no significant difference was found in the amount of glycosaminoglycan between them. Using human gastric carcinoma cell lines, the interaction of fibroblasts (cell line WI-38) with carcinoma cells was studied in vitro. In well-differentiated adenocarcinoma, the amount of glycosaminoglycan secreted into the interface between carcinoma cells and fibroblasts was much larger (about 20-fold) than that into the interface between the carcinoma cells and the bare culture dish. However, in poorly differentiated adenocarcinoma cells, glycosaminoglycan secretion was not affected by the presence of fibroblasts. The effects of the extracellular matrix produced by carcinoma cells on the attachment and growth of fibroblasts were also examined in vitro. The attachment-promoting and growth-promoting activities of the matrix substance produced by poorly differentiated carcinoma was about 10 times greater than that caused by the well-differentiated adenocarcinoma cell matrix substance. Proteoglycan and glycosaminoglycan were identified in malignant and benign non-epithelial tumors. More proteoglycans containing mainly chondroitin sulfate could be detected in malignant tumors than in benign tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Tumor necrosis factor-alpha induces p53-dependent apoptosis in rat glioma cells

In this study, we demonstrated that tumor necrosis factor (TNF)-alpha inhibited the viability of rat glioma (C6) cells and induced apoptosis but did not affect the viability of rat newborn brain, mainly astroglial cells. The antitumor activity of TNF-alpha against C6 cells was partially inhibited by actinomycin D and cycloheximide, suggesting that it is possibly dependent upon new ribonucleic acid and protein synthesis. The results of immunoblotting assay demonstrated that TNF-alpha decreased the expression of mutant p53 protein but induced the expression of wild-type p53 in C6 cells during apoptosis. We suggest that TNF-alpha may activate the function of wild-type p53 protein by the suppression of mutant p53, at least indirectly, and induce p53-dependent apoptosis in glioma cells.

Activation mechanism of phospholipase D involved in the generation of lipid mediators in cultured Madin-Darby canine kidney cells

Addition of 100 nM phorbol 12-myristate 13-acetate (PMA), an active phorbol diester, to quiescent cultured Madin-Darby canine kidney (MDCK) cells caused a maximal stimulation of phosphatidylethanol formation within 1-2 h in the presence of 1% ethanol, indicating the activation of phospholipase D (PLD). The specificity of phorbol diesters for the activation of PLD activation was confirmed by the fact that phorbol 12,13-dibutyrate (PDBu) was effective, whereas 4 alpha-phorbol 12,13-didecanoate (4 alpha-PDD) was without effect. Down-regulation caused by the long-term pretreatment of the cells with active phorbol diesters significantly decreased the production of phosphatidylethanol. Staurosporine, a well known protein kinase (PK)C inhibitor at 1 microM, decreased the activation of PLD. Taken together, these observations suggested the involvement of PKC in the activation of PLD. The cellular PLD activity was found to be selectively localized in the particulate fraction by centrifugation at 12,000 x g. The particulate PLD showed the selective substrate specificity for phosphatidylcholine rather than phosphatidylethanolamine. In response to the addition of 100 nM PMA, 1,2-diacylglycerol (DG) increased in a biphasic fashion. In view of the time course of the activation of PLD, the second increase in the 1,2-DG around 20 min was contributed by the activation of PLD. In response to the simultaneous addition of 100 nM PMA and 100 nM A23187, the cultured MDCK cells activated the arachidonate cascades to form prostaglandin (PG)E2 and PGF2 alpha as major products, requiring slower 24 h to reach maximal levels.(ABSTRACT TRUNCATED AT 250 WORDS)

MDM2 protein confers the resistance of a human glioblastoma cell line to cisplatin-induced apoptosis

Induction of apoptosis in tumor cells is an important mechanism of chemotherapy-induced cell death. The tumor-suppressor gene p53 is required for the efficient activation of apoptosis following chemotherapy. However, the molecular mechanism regulating p53-associated apoptosis remains controversial. In this study, we show that the expression of both wild-type p53 and MDM2 (murine double minute 2) proteins was induced when cis-diamminedichloroplatinum (cisplatin) caused apoptosis in human glioblastoma U87-MG cells, which expressed neither wild-type p53 nor MDM2 protein prior to treatment. Overexpression of MDM2 in U87-MG cells transfected with human mdm2 expression vector conferred the resistance of tumor cell to cisplatin-induced apoptosis. In contrast, the treatment with mdm2 antisense oligonucleotide targeted against mdm2 mRNA increased the susceptibility of tumor cells to apoptosis. Changes in expression level of MDM2 protein, however, did not affect the expression of wild-type p53 protein. These findings suggest that MDM2 protein may act as a negative regulator of cisplatin-induced apoptosis, and moreover, may play an important role in the development of resistance to cisplatin in human tumors.

[Aspergillus lumbar discitis in a patient with acute lymphoblastic leukemia following induction therapy]

A 47-year-old female was admitted in October 1988 because of anemia and lymphoblastic cells in peripheral blood. A bone marrow aspirate was hypercellular with 93.9% lymphoblasts negative for peroxidase staining. The case was diagnosed as ALL (L2), and treated with JALSG ALL-87 regimen. She developed spiky fever and endotoxin shock due to bacteremia caused by pseudomonas aeruginosa, then was treated with several antibiotics. With the recovery of leukocytes, the chest X-ray showed an infiltrative shadow and a cavity forming lung abscess resembling aspergilloma in her left lung. The cavity improved of transbronchial infusion following amphotericin B (AMPH-B). Although she achieved complete remission, she felt severe lumbago accompanied by a marked erosion of the vertebral body with disc space narrowing on her X-ray. Then she underwent surgery to remove a disc abscess, and 1 colony of the aspergillus species was cultured from the specimen. She was treated with intravenous AMPH-B, and post remission therapies were performed under the injection of anti-fungal agents. No remarkable symptoms of complications were recognized during the chemotherapy. AMPH-B is useful and safe for the management of aspergillus discitis.

Relationship between responsiveness to colony stimulating factors (CSFs) and surface phenotype of leukemic blasts

We examined the responsiveness of leukemic cells to colony stimulating factors (CSFs) as determined by 3H-TdR incorporation and surface phenotypes of leukemic blasts. In acute myeloid leukemia (AML), CD13 and/or CD33 positive and HLA-DR negative M1 and M3 cases tended to show high response to G-CSF, GM-CSFs and IL-3, however, all HLA-DR positive M1, M2, M4 and M5 cases were unresponsive to CSFs but showed high autonomous growth. In acute lymphocytic leukemia (ALL), no response was observed to any CSFs but high autonomous growth was found in mixed leukemia cases. Sole T or B lineage cases showed low autonomous growth. These results suggest the varied nature of the proliferative state in leukemia and the existence of a subgroup in M1.

Combination therapy with cisplatin and nifedipine inducing apoptosis in multidrug-resistant human glioblastoma cells

The authors found that multidrug-resistant human glioblastoma GB-1 cells demonstrated significantly more resistance to cisplatin than did nondrug-resistant human glioblastoma U87-MG cells (p < 0.1). They therefore attempted to determine whether calcium channel blockers enhance the antitumor activity of cisplatin against GB-1 cells. Nifedipine, a dihydropyridine calcium channel blocker, significantly enhanced the antitumor effect of cisplatin on GB-1 cells (p < 0.05). In the absence of normal extracellular Ca++, nifedipine enhanced the cytotoxicity of cisplatin. In addition, the antitumor activity of combined cisplatin and nifedipine was inhibited both by actinomycin D and cycloheximide, suggesting that such activity is dependent upon new RNA and protein synthesis. Surprisingly, DNA fragmentation assay demonstrated that synergism between cisplatin and nifedipine resulted in apoptosis (programmed cell death) at a relatively low concentration of cisplatin, which when tested alone did not induce apoptosis. In addition, it was demonstrated that nuclei from GB-1 cells lacked a Ca(++)-dependent endonuclease that degrades chromatin into nucleosomes and that calcium ionophore A 23187 did not decrease the viability of GB-1 cells. The above findings suggest the hypothesis that the noncytotoxic agent nifedipine synergistically enhances the antitumor effect of cisplatin on multidrug-resistant GB-1 cells lacking Ca(++)-dependent endonuclease, and subsequently induces apoptosis via its interaction with an as yet uncharacterized functional site other than the calcium channel on GB-1 cells.

Combination therapy with cisplatin and nifedipine induces apoptosis in cisplatin-sensitive and cisplatin-resistant human glioblastoma cells

We attempted to determine whether calcium channel blockers (CCBs) enhance the anti-tumour activity of cis-diamminedichloroplatinum (cisplatin) against both cisplatin-sensitive human glioblastoma U87 MG cells and cisplatin-resistant U87-MG-CR cells, the latter of which we developed for resistance to cisplatin. Nifedipine, a dihydropyridine class CCB, significantly enhanced the anti-tumour effect of cisplatin on these two cell types in vitro and in vivo. Our findings also indicated that, in the absence of normal extracellular Ca2+ nifedipine was capable of enhancing the cytotoxicity of cisplatin. In addition, this anti-tumour activity was partially inhibited by actinomycin D and cycloheximide, suggesting that it is possibly dependent upon new RNA and protein synthesis. Interestingly, ultrastructural analysis, DNA fragmentation assay and cell cycle analysis demonstrated that synergism between cisplatin and nifedipine results in apoptosis (programmed cell death) at a relatively low concentration of cisplatin, which when tested alone did not induce apoptosis. Furthermore, we demonstrated that nuclei from these cells lack a Ca(2+)-dependent endonuclease that degrade chromatin in the linker region between nucleosomes. In conclusion, our studies suggest that the non-cytotoxic agent nifedipine is able to synergistically enhance the anti-tumour effects of cisplatin on U87-MG and U87-MG-CR cells lacking a Ca(2+)-dependent endonuclease and subsequently to induce apoptosis via interaction of nifedipine with an as yet uncharacterised functional site other than a calcium channel on target cells.

The SMS1 gene encoding a serine-rich transmembrane protein suppresses the temperature sensitivity of the htr1 disruptant in Saccharomyces cerevisiae

A new gene (SMS1; serine-rich multi-copy suppressor) of Saccharomyces cerevisiae was isolated by the ability to suppress the temperature sensitivity of the htr1 disruptant (Kikuchi et al. (1994) Mol. Gen. Genetics, in press) by increasing its gene dosage. The predicted gene product contains a serine-rich domain followed by a putative transmembrane region. The SMS1 gene was physically and genetically mapped in the region near cdc3 on chromosome XII R.