[Prognostic factors of nasopharyngeal carcinoma treated by radiotherapy]

This study was a retrospective analysis of 82 patients with histologically confirmed nasopharyngeal carcinoma, who were treated at Keio University Hospital from March 1983 to March 1993. We studied all cases(62% of them were stage IV) with regard to their prognostic factors and chronic side effects induced by radiation. All patients were received extended-field radiotherapy from the base of the skull to the supraclavicular lymph node area. The five- and ten-year overall survival rates for the entire group were 59% and 49%, respectively. Three stage I patients were alive without recurrence or metastases for more than 5 years. The ten-year survival rate stage II-III for patients (23 patients) was 78%, and for stage IV (56 patients) 37%. The five-year survival rate of patients in T2-3 group without lymph node metastasis was 88%, while it was reduced to 55% for patients with metastasis. The prognosis of T4 patients was very poor: their five-year survival rate was 37% with lymph node metastasis, and 35%, without lymph node metastasis. Patients under 46 years old showed an increased survival rate compared with patients over 46 years old. Patients who completed less than 52 days of radiation therapy found to have a better prognosis than those receiving radiation for a longer period. Our multivariate analysis indicated that age, radiation period and N-factor were statistically significant in influencing prognosis. Hearing loss occurred relatively high with 20% of cumulative incidence in our study, probably because they received radiation therapy with the extended field including bilateral middle and inner ear. Extended-field radiotherapy for patients with nasopharyngeal carcinoma might contribute to improving their cure-rate, and precise radiation planning is warranted to avoid the late complications such as hearing loss.

Natural course of brainstem auditory evoked potentials in infants less than 6 months old with asymptomatic meningomyelocele

It is difficult to estimate the accurate onset of symptoms clinically resulting from Chiari II malformation. Brainstem auditory evoked potentials (BAEPs) may be a useful method in the selection of potential candidates for surgery. We studied 153 BAEPs in 131 asymptomatic infants under 6 months of age with meningomyelocele (MMC). Both the wave latencies and interpeak latencies (IPLs) gradually became shorter during the first 6 months of life in asymptomatic infants with MMC. In particular, shortening of the III-V IPLs and the I-V IPLs was observed from 1 to 4-6 months of age in these infants. These may be characteristic parameters of central auditory function (III-V IPLs) and global auditory function (I-V IPLs). Maturation of brainstem function as viewed by BAEPs in asymptomatic infants with MMC was delayed when compared to data in normal neonates and infants. These data on asymptomatic infants with MMC could potentially be a good reference for selecting the modalities of treatment in infants with symptomatic Chiari II malformation.

[Combination chemotherapy with 5-FU and CDDP or CDDP analog for head and neck cancer]

Combination chemotherapy with CDDP and 5-FU is one of the effective regimens for head and neck cancer. We studied the difference in the effects and adverse effects between two kinds of schedules of CDDP administration for CDDP-5-FU combination chemotherapy. For 13 patients, CDDP was administered on 5 consecutive days from day 1 to day 5 at a daily dose of 16 mg/m2 (Regimen A). For 14 patients CDDP was administered 80 mg on day 1 (Regimen B). 5-FU was administered 700 mg/m2/ day as a continuous drip infusion for 120 hours from day 1 to day 5. For regimen A, the response rate was 77%; for regimen B, it was 64%. The pattern of adverse effects showed a difference. Regimen B was more toxic for renal function than regimen A. But regimen A showed toxicity for bone marrow function. Acute phase nausea and vomit appeared more frequently in regimen B. The difference in the adverse effect pattern, which depends on the schedule of CDDP administration, seems important in order to apply this regimen for head and neck cancer patients safely. The schedule of CDDP administration should be changes depending on the renal and bone marrow function of patients. In order to evaluate the efficacy of UFT as adjuvant chemotherapy, UFT was administered p.o. to patients with maxillary sinus carcinoma for more than one year after definitive treatment with surgery or radiotherapy. Fifteen patients with UFT adjuvant chemotherapy showed significantly better survival rates than patients without adjuvant chemotherapy. We also studied adjuvant chemotherapy with CBDCA and FT for patients with advanced head and neck cancer. Administration with UFT (600 mg/day) from day 1 to day 14 with CBDCA 350 mg/m2 at day 7 was repeated more than twice. This regimen showed low toxicity and better survival for nasopharyngeal cancer patients. More clinical trials with this regimen for adjuvant chemotherapy are needed.

Behavior of calcium and phosphate in artificial casein micelles

This study investigated the behavior of Ca and phosphate in artificial casein micelles using 45Ca and 32P by means of UF, equilibrium dialysis, and gel permeation HPLC in the presence of 6 M urea. Artificial casein micelles were prepared at a casein concentration of 2.5% with 30 to 40 mM Ca, 22 to 27 mM phosphate, and 10 mM citrate using 45Ca or 32P. About 75 and 65% of colloidal 45Ca and 32P, respectively, in artificial casein micelles that were formed in the presence of 30 mM Ca and 22 mM phosphate were exchanged after dialysis of artificial casein micelles against a simulated milk ultrafiltrate at 4 degrees C for 72 h. The percentages of 45Ca and 32P in the fraction of casein aggregates that were crosslinked by micellar Ca phosphate were 26.9 and 27.6%, which decreased to about 10% after equilibrium dialysis against a simulated milk ultrafiltrate at 4 degrees C for 72 h. The proportion of exchanged colloidal 45Ca and 32P in artificial casein micelles during dialysis for 72 h were higher at 25 degrees C than at 4 degrees C, suggesting that the exchange of Ca and phosphate between the diffusible and colloidal phases depended on temperature. The results suggest that the exchange of Ca and phosphate between diffusible and colloidal phases proceeds slowly, and a portion of the Ca and phosphate in the artificial casein micelles is difficult to exchange.

Fluorescence localization of anti-pregnant rat kidney antibody and lectin binding analysis in exencephalic rat embryos

We sought to determine the distribution of anti-pregnant rat kidney serum (ARKS) in fetuses that subsequently developed a form of neural tube defect (NTD). We produced exencephaly in rat embryos by injecting a rabbit anti-pregnant rat kidney serum into the peritoneal cavity of pregnant Wistar rats on day 7 of gestation; 71.1% (27/38) of the rat embryos developed this anomaly. Fluorescence immunohistochemical studies were performed to localize ARKS binding in the embryos. We also investigated the binding of two lectins, concanavalin A (ConA) and wheat germ agglutinin (WGA), to glycoconjugates on neuroepithelium during the process of neurulation in rat embryos injected with normal rabbit serum (NRS) and ARKS. We found for the first time that ARKS directly affected the neural tube during neurulation. Intense fluorescence was observed on the luminal side of the neuroepithelium in the intercellular region and on the basement membrane of the neural tube in embryos on day 9 of gestation (GD9). In GD21 embryos there was much more intense fluorescence in the extracellular matrix and the ependymal lining cells of the ventricles than in controls. The binding of the two lectins on the cell surface of the neuroepithelium during neurulation was different in rat embryos injected with ARKS than in normal embryos injected with NRS. These results support the idea that simple nonclosure and overgrowth constitute the mechanism of NTD. However, the lectinbinding data suggest that dysraphic states may be induced by cell-to-cell adhesive molecular failure.

Acid lipase inhibitor in chicken plasma identified as apolipoprotein A-I

We have reported a inhibitor of acid lipases in liver lysosomes and erythrocytes from chickens [M. Fujii et al., Int. J. Biochem., 22, 895-898 (1990)]. In this paper, the properties of the inhibitor were described in comparison with those of apo A-I of chicken. The purified inhibitor migrated with the same mobility on SDS-PAGE as apo A-I, and had a molecular weight of 27,000. The peptide map from the lipase inhibitor was similar to that of apo A-I. Antibodies to the acid lipase inhibitor also reacted with apo A-I. Apo A-I inhibited the acid lipase activities of liver lysosomes and erythrocytes from chickens as strongly as the lipase inhibitor. The N-terminal amino acid sequence of lipase inhibitor was identical to that of apo A-I as far as residue 20. The amino acid sequence of peptides obtained from the inhibitor by cleavage with CNBr corresponded to internal sequence of apo A-I, and so the CNBr-peptides were derived by cleavage after the methionine residues in apo A-I. The findings showed that the inhibitor of the acid lipases in liver lysosomes and erythrocytes from chickens was identical to apo A-I.

Formation of crossline as a fluorescent advanced glycation end product in vitro and in vivo

Crossline is one of the major advanced glycation end products resulting the reaction mixture of free amino group(s) such as epsilon-one in lysine with D-glucose in vitro. To study crossline formation on proteins in vitro and in vivo, polyclonal antiserum to the crossline hapten was prepared. This antiserum reacted with bovine and human serum albumin that had been modified by prolonged incubation with glucose as well as with crossline itself. Antisera did not react with unmodified serum albumin or the other Maillard-related compounds. Crossline was formed in a time-dependent manner when a mixture of six different proteins was incubated with glucose at pH 7.2 or 9.0. Crossline levels could be measured in rat lens proteins and the levels increased with age. The crossline content of lens proteins in diabetic rats was more than two-fold higher than that of age-matched controls. Results of this study suggest that most proteins containing advanced glycation end products have crossline-like structures. Measurement of crossline-like structures in biological specimens may provide an index of aging and of the development of diabetic complications.

Serum antibody responses of foals to virulence-associated 15- to 17-kilodalton antigens of Rhodococcus equi

Humoral immune responses in 16 foals to virulence-associated 15- to 17-kDa antigens of Rhodococcus equi were studied during the first fourteen weeks of life on two horse-breeding farms with a persistent incidence of R. equi infection. Serum antibody levels specific for 15- to 17-kDa antigens were measured by enzyme-linked immunosorbent assay and Western immunoblotting. Immunoglobulin G (IgG) antibodies specific to 15- to 17-kDa antigens were detected by all the foals. R. equi was found in the feces of foals during week 1 of life, and the number of fecal R. equi rapidly increased to the highest level. Virulent R. equi were isolated from the feces of the foals at a high frequency and from their environmental soil on the farms. Evidence that serum antibody response to 15- to 17-kDa antigens of virulent R. equi occurred naturally in every foal in correlation with the quantitative changes of fecal R. equi during the first 1 to 3 months of life suggests that intestinal virulent R. equi might be the most important source of antigenic stimulation in foals from contaminated farms.

Primary lung cancer associated with diffuse granulomatous lesions in the pulmonary parenchyma

A 60-year-old man was admitted to our hospital for productive cough. Chest roentgenography and CT scan disclosed a left hilar tumor invading the mediastinum, with mediastinal lymphadenopathy and diffuse micronodular shadows in both lung fields. A biopsied sample of the tumor revealed squamous cell carcinoma, while noncaseating epithelioid cell granulomas were observed in the samples obtained by transbronchial lung biopsy. The granulomas in the pulmonary parenchyma were determined to be sarcoid reactions secondary to lung cancer, since there was no evidence of sarcoidosis. Combination chemotherapy was effective for the tumor, and the granulomas disappeared after completion of the chemotherapy. These findings suggest the presence of a relationship between sarcoid reactions and lung cancer in this case.

Cyclic AMP regulates expression of activin and inhibin subunit mRNAs in the mouse placenta and decidua: a short communication

We examined whether cAMP regulates expression of activin/inhibin subunit mRNAs in the mouse placenta and decidua. 8-Bromo-cAMP inhibited expression of inhibin alpha-subunit mRNA but stimulated expression of activin/inhibin beta A- and beta B-subunit mRNAs in placenta and decidua by the 3rd day of culture. Forskolin and cholera toxin also regulated expression of activin/inhibin subunit mRNAs in the same manner. However, activin-A did not affect expression of activin/inhibin subunit mRNAs. These findings suggest that cAMP inhibits inhibin production but stimulates activin production in the mouse placenta and decidua.

Supra- and infratentorial multiple cavernous angiomas in an infant: report with MR evaluation of an unusual case

A rare case of multiple cavernous angiomas with repeated hemorrhages in a 9-month-old male infant is presented, together with sequential computed tomography (CT) and magnetic resonance (MR) images. The infant underwent hematoma evacuation for left cerebellar hemorrhage and his postoperative course was uneventful. The multiple cavernous angiomas receded gradually without any treatment except the hematoma evacuation. Two years following presentation, he continues to do well. To the authors' knowledge, this is the first report of multiple cavernous angiomas with brain stem involvement in an infant.

[A case of lung metastasis from breast cancer successfully treated by FLEP (5-FU leucovorin, etoposide CDDP) combined arterial infusion chemotherapy]

A 33-year-old woman had undergone left mastectomy after diagnosis of breast cancer. One year after operation, multiple lung metastasis was confirmed by chest X-ray and CT scan. The patient received 6 courses of cyclophosphamide, epirubicin, and 5-FU (CAF) combined chemotherapy. However, the lesions were increased and the result of this chemotherapy was judged to be "progressive disease" (PD). A catheter was placed in the thoracic aorta, and FLEP combined intraaortic infusion chemotherapy was performed. The patient received 4 courses of 5-FU (325/mg/m2/day, civ, on day 1-5), leucovorin (30 mg/body/day, iv, on day 1-5), etoposide (60/mg/m2/day, ia, on day 7 and day 21), cisplatin (60/mg/m2/day, ia on day 7 and 21) every 4 weeks. The multiple lung metastasis almost disappeared on chest examination, and found to be less than 1 cm in diameter on CT scan. This result suggests FLEP combined chemotherapy is effective as a second-line treatment of recurrent breast cancer.

Prognostic factors for patients with advanced non-small cell lung cancer: univariate and multivariate analyses including recursive partitioning and amalgamation

In an attempt to determine the prognostic significance of pretreatment factors for patients with advanced non-small cell lung cancer (NSCLC), 24 pretreatment clinical variables were analyzed for 185 patients with NSCLC who underwent chemotherapy and/or radiotherapy between 1985 and 1994. Following univariate analysis, we applied two multivariate statistical techniques. In a Cox regression mode, independently significant factors influencing patient survival included performance status (PS), disease stage, hemoglobin level, and serum calcium level. Recursive partitioning and amalgamation (RPA) resulted in three distinct prognostic subgroups based on PS, stage, weight loss, and hemoglobin level. The best survival was observed for patients with a good PS and Stage III disease who had a hemoglobin level > 11 g/dl. The worst survival was observed for patients with a poor PS and presence of weight loss irrespective of stage. All other patients had an intermediate prognosis. Median survival times were 95.1 weeks, 17.1 weeks and 39.3 weeks, respectively (P < 0.00005). The results of our analyses show that three important prognostic subgroups could readily be discerned using RPA.

[Comparative clinical study of adjuvant postoperative chemotherapy (5-FU, Tegafur, 5-FU + MMC) in curatively resected cases of gastric cancer. Study Group on 5-FU Oral Adjuvant Chemotherapy in Gastric Cancer]

A multi-center collaborative study was conducted in curatively resected gastric cancer patients at Stages II and III to compare oral 5-FU (Group A), oral Tegafur (Group B) and i.v. MMC + oral 5-FU (Group C). From May 1982 to April 1985, 1,012 cases were enrolled at 55 institutions. Some 138 (13.8%) were excluded, and 874 were analyzable. In the analysis of background factors, Group B had more cases with tumor of large diameter and advanced Stage. Adverse effects were relatively mild in all groups, and there was no problem in drug tolerance. Five-year survival rate was 67.6%, 62.4% and 68.6% in Groups A, B and C, respectively, reflecting no significant difference among them. It was 85.0%, 83.0% and 81.1% in Stage II and 52.5%, 51.0% and 59.0% in Stage III of Groups A, B and C, respectively. No significant difference was found, but Stage III of Group C showed a slightly higher survival rate. Supportive clinical study will be required to assess the usefulness of MMC as an introduction therapy. We found no difference in efficacy between 5-FU and Tegafur as maintenance therapy. The life-prolongation effect of fluoropyrimidines in comparison with surgery alone should be studied separately.

[Head and neck cancer]

Before CDDP was clinically used, combination chemotherapy regimens like BLM + MMC, VCR + MTX-LV + BLM, VCR + MTX-LV + BLM + MMC had been used for recurrent tumors of the head and neck. In a phase II study with CDDP, we experienced two patients with long-term survival (12, 15+) who were treated with CDDP as a second-line chemotherapy for recurrent tumors. Cisplatin was evaluated as a potentially curative agent. After that, CDDP based regimens have been used as neo-adjuvant setting (first-line chemotherapy). So it became quite difficult to make up a second-line chemotherapy since CDDP based regimens have been used as the first-line chemotherapy. We conducted basic research on second-line chemotherapy for recurrent head and neck cancer: (1) cross-resistance studies on head and neck cancer cell lines resistant to CDDP, 5-FU, MTX and BLM; (2) second line chemotherapy for CDDP + PEP combination chemotherapy, which was developed by us, in human KB cell line; and (3) effects of etoposide plus mitomycin C on head and neck squamous cell carcinoma in monolayer and multicellular tumor spheroid. Based on our long-term experience with chemotherapy for head and neck cancer, and the results of the above-mentioned basic research, we established a policy to select second-line chemotherapy for recurrent head and neck cancer, especially in cases previously treated with chemotherapy.

A solitary Peutz-Jeghers-type hamartomatous polyp of the rectum: report of a case and review of the literature

A solitary Peutz-Jeghers-type polyp of the rectum in a 64-year-old Japanese man is reported. Barium enema and endoscopic examination revealed a solitary polypoid lesion in the rectum. The polyp was pedunculated, and measured 2 x 1.5 x 1.5 cm. The patient had neither mucocutaneous pigmentation nor a family history of gastro-intestinal polyposis. Histopathologically, this polyp had an arborizing muscular network originating from the muscularis mucosa, and was covered by well organized mucosa with epithelial hyperplasia. The smooth muscle bundles in the polyp were thicker than those seen in Peutz-Jeghers syndrome, but their network was not as complex.

Acute and chronic regulation of serum sex hormone-binding globulin levels by plasma insulin concentrations in male noninsulin-dependent diabetes mellitus patients

This study was undertaken to investigate the relationship of the serum sex hormone-binding globulin (SHBG) levels with the plasma insulin concentration and with the insulin resistance in male subjects with noninsulin-dependent diabetes mellitus (NIDDM). This investigation comprised 12 patients with NIDDM and 16 normal subjects matched for age, sex, and body mass index (BMI). There was a significant increase in insulin levels (P < 0.03) and a decrease in SHBG levels (P < 0.01) in the diabetic group as compared with those of the normal group. The sex hormone and plasma insulin levels were measured in NIDDM patients undergoing exercise and dietary therapy. Insulin sensitivity was evaluated by the hyperinsulinemic euglycemic clamp technique expressed as the glucose infusion rate (GIR) before and after the treatment. The SHBG levels correlated significantly with the insulin concentrations (r = -0.643, P < 0.05) and with the GIR (r = 0.615, P < 0.05) before the treatment. The SHBG levels (P < 0.02) and GIR (P < 0.01) increased, and the insulin concentrations (P < 0.01) decreased significantly during the treatment. The SHBG levels showed a negative and significant correlation with the plasma insulin concentrations at the end of the clamp study before (r = -0.615, P < 0.05) and after (r = -0.626, P < 0.05) the treatment. These findings suggest that, in the hyperinsulinemic state, plasma insulin has a direct effect on the SHBG levels. SHBG levels decreased significantly during the clamp study before (P < 0.02) and after (P < 0.01) the treatment. This may represent the acute effect of insulin on the SHBG levels. Briefly, these results suggest that insulin may directly affect the SHBG levels and that SHBG may constitute an index of the insulin resistance only in the hyperinsulinemic state.

Purification and characterization of a prolidase from Aureobacterium esteraromaticum

An EDTA-insensitive prolidase (proline dipeptidase, EC 3.4.13.9) was isolated from a cell-free extract of Aureobacterium esteraromaticum IFO 3752. The enzyme was purified almost to homogeneity using acetone precipitation, hydrophobic chromatography, ion-exchange chromatography, and gel-permeation chromatography. The enzyme has a molecular weight of about 440,000 by gel permeation chromatography, and about 40,000 by SDS polyacrylamide gel electrophoresis. The isoelectric point was 4.6. The enzyme hydrolyzed aminoacylprolines such as Ser-Pro. Thr-Pro, Gly-Pro, Ala-Pro, Ile-Pro, Leu-Pro, and Pro-Pro. It also hydrolyzed Gly-Hyp and Pro-Hyp. The rate of hydrolysis for Pro-Hyp was the highest among the substrates tested. Optimum pH for hydrolyzing Pro-Hyp was 9.0 and the enzyme was stable in the pH range from 5 to 10. The optimum temperature was estimated to be 45 degrees C using 10 min of reaction. At least 90% of the initial activity remained after 30 min of incubation at 60 degrees C. p-Chloromercuribenzoic acid and o-phenanthrolin inhibited the enzyme's activity while EDTA did not. Addition of Mn2+ ion did not stimulate activity. These results suggest either that the metal ion in the enzyme may be tightly bound to the polypeptide chain, or that the enzyme is not a metallo-enzyme but a thiol-enzyme.

Distribution of amyloid bodies in the aged human vestibulocochlear nerve

We tried to elucidate the localization and distribution of amyloid bodies (Corpora amylacea) in the human vestibulocochlear nerve stained with luxol fast blue-periodic acid Schiff-hematoxylin using of a combination of an image analyzing computer system and a microscope fitted with a drawing tube. After having observed each section of the vestibulocochlear nerve from the brain stem to the fundus of the internal auditory meatus, we counted the numbers of amyloid bodies in three different parts for each of three corpses, and measured the areas. We found that amyloid bodies of the vestibulocochlear nerve are concentrated to the limiting glial portion of the nerve more than to the nerve parenchyma, and amyloid bodies are not seen in the vestibulocochlear nerve peripheral to the transitional zone. Our quantitative trial proved that the amyloid body was larger in the 8th decade than in the 6th or 7th decade of life.

Interferon-gamma-inducing factor enhances T helper 1 cytokine production by stimulated human T cells: synergism with interleukin-12 for interferon-gamma production

The novel cytokine interferon-gamma-inducing factor (IGIF) augments natural killer (NK) cell activity in cultures of human peripheral blood mononuclear cells (PBMC), similarly to the structurally unrelated cytokine interleukin (IL)-12. IGIF has been found to enhance the production of interferon-gamma (IFN-gamma) and granulocyte/macrophage colony-stimulating factor (GM-CSF) while inhibiting the production of IL-10 in concanavalin A (Con A)-stimulated PBMC. In this study, when anti-CD3 monoclonal antibody (mAb)-stimulated human enriched T cells were exposed to IGIF, the cytokine dose-dependently enhanced the proliferation of the cells and this could be completely inhibited by a neutralizing antibody against IL-2 at lower concentrations of IGIF. Neutralizing antibody against IFN-gamma had only insignificant inhibitory effects on T cell proliferation at higher concentrations of IGIF. Enzyme-linked immunosorbent assays (ELISA) revealed that, like PBMC, T cells exposed to IGIF produced large amounts of IFN-gamma; however, changes in the production of IL-4 and IL-10 were minimal. IGIF, but not IL-12, significantly enhanced IL-2 and GM-CSF production in T cell cultures, as determined by CTLL-2 bioassay and ELISA, respectively; however, both IGIF and IL-12 enhanced IFN-gamma production by the T cells. When T cells were exposed to a combination of IGIF and IL-12, a synergistic effect was observed on the production of IFN-gamma, but not on production of IL-2 and GM-CSF. In conclusion, IGIF enhances T cell proliferation apparently through an IL-2-dependent pathway and enhances Th1 cytokine production in vitro and exhibits synergism when combined with IL-12 in terms of enhanced IFN-gamma production but not IL-2 and GM-CSF production. Based on structural and functional differences from any known cytokines, it was recently proposed that this cytokine be designated interleukin-18.

Morphometrical analysis of nucleolin immunohistochemistry in meningiomas

Nucleolin (110 kDa) is a major nucleolar protein in eukaryotic cells and one of the nucleolar organizer region (NOR)-associated proteins. We studied immunohistochemically 32 cases of meningioma, using specific antisera against nucleolin, and analyzed various nucleolin parameters, such as the number of regions and the total area of nucleolin staining per nucleus. The mean number and area of nucleolin stainings per nucleus were compared with the histological malignancy and Ki-67/MIB-1 proliferation index; the correlation with parameters of silver-stained NOR (AgNOR) was also studied. The results showed that there were statistically significant differences in the mean number and area of nucleolin stainings per nucleus between meningiomas and other two groups, atypical and anaplastic meningiomas (P < 0.05), although there was no difference between atypical and anaplastic meningiomas. The mean number and area of nucleolin stainings per nucleus were correlated with the incidence of Ki-67 positivity and AgNOR area. In view of the technical problems inherent in AgNOR staining, immunohistochemistry for nucleolin may represent a more specific and reproducible means for NOR visualization and be a promising technique for assessing cell proliferation.

A panel of radiation hybrids defining the 7q31-q32 region of human chromosome 7

Mouse A9 cells containing human chromosome 7 tagged with pSV2neo were irradiated with X-rays and fused to A9 cells to isolate G418-resistant clones. From these clones, we selected radiation hybrids that contained 10-40 Mb of human DNA apparently at a single site of their genome by FISH analysis using human repetitive sequences as a probe. Then we made a panel of hybrids that contained various fragments of the 7q31-q32 region and cover its entire region altogether by PCR with STS markers of human chromosome 7. This panel is useful in chromosome transfer experiments since the dominant selective marker neo gene is attached to human DNA.