Testicular follicle-stimulating hormone receptors in idiopathic male infertility

To ascertain whether abnormalities in testicular binding of follicle-stimulating hormone (FSH) are related with spermatogenic impairment found in idiopathic male infertility, we measured FSH receptors in testicular tissues obtained by biopsy from 48 infertile men. The 48 infertile men were divided into 3 groups by histological grading using Johnsen's score count, and testicular FSH receptors among these groups were compared. Although 9 of the 18 infertile men with low Johnsen's score count and 5 of the 15 men with middle score count had no obvious FSH binding sites with high affinity, all 15 men with a high score count had high affinity FSH binding sites. In connection with high affinity binding sites for FSH, maximum binding number (Bmax) decreased significantly with the degree of spermatogenic impairment, but the association constant (Ka) was similar among the 3 groups. The present findings demonstrate that the decrease in testicular high affinity binding sites for FSH is related with the degree of spermatogenic impairment found in idiopathic male infertility.     

Large deletions at the HPRT locus associated with the mutator phenotype in a Bloom's syndrome lymphoblastoid cell line

Bloom's syndrome (BS) is an autosomal recessive disorder with a high cancer incidence. BS cells exhibit increased chromosomal instability and sister-chromatid exchange. The rate of spontaneous mutation at the locus encoding hypoxanthine phosphoribosyltransferase (HPRT) in a lymphoblastoid cell line derived from a BS patient, GM3403, was 1.39 × 10⁻⁶ mutations/cell/generation, whereas that in TK6, a lymphoblastoid cell line derived from an individual who is not suffering from BS, was 1.75 × 10⁻⁸ mutations/cell/generation. Molecular analysis of the HPRT gene in mutant clones by multiplex polymerase chain reaction revealed that 83.3% of the spontaneous mutants from GM3403 cells contained deletions at the HPRT locus, whereas 30.8% of mutants from TK6 cells had deletions. Approximately half of the BS mutants had lost the entire gene. Some mutant clones of GM3403 had also lost markers near the HPRT locus, although no mutant clones from TK6 cells had lost these markers. These results indicate that the mutator phenotype of BS cells is mainly due to an increase in large DNA alterations, reflecting the remarkable genomic instability that could be responsible for cancer proneness in this disease. © 1996 Wiley-Liss, Inc.     

Chemoradiation therapy using radiotherapy, systemic chemotherapy with 5-fluorouracil and nedaplatin, and intra-arterial infusion using carboplatin for locally advanced head and neck cancer - Phase II study

To improve the treatment results for locally advanced head and neck cancer, chemoradiation therapy by radiotherapy, systemic chemotherapy with 5-fluorouracil (5FU) and nedaplatin (NDP), and intra-arterial therapy using carboplatin (CBDCA) was performed. Thirty-two patients were entered into the study between July 1997 and August 2002. According to the TNM staging (1997), 14 patients had stage III lesions, and 19 patients had stage IV (M0) lesions. Alternating chemoradiotherapy was performed by the following regimen. Initially, systemic chemotherapy was administered, followed by 4 weeks of radiotherapy (36 Gy/20 fractions; wide field irradiation) starting 2 days after chemotherapy, a second course of systemic chemotherapy 2 days after radiotherapy, and a second course of a reduced field radiotherapy (30 Gy/15 fractions) 2 days after chemotherapy. Arterial injection therapy was administered in the latter half of radiotherapy after the end of the second course of systemic chemotherapy. For systemic chemotherapy, 5FU at 3500 mg/m²/120 h was intravenously administered for 5 days (Days 1–5), and NDP at 120 mg/m²/6 h was administered on Day 6. An intra-arterial agent using CBDCA was continuously infused by a portable electrical pump for 4 (to 6) weeks. The total dose of CBDCA was AUC 6 as established by Calvert’s formula. The 5-year local control rate was 59%. The 5-year overall survival rate was 51%. There were no clinically significant adverse effects. Chemoradiation therapy by radiotherapy, systemic chemotherapy, and intra-arterial chemotherapy for locally advanced head and neck cancer may be useful for improving treatment results.     

Specificity of mutations induced by N-methyl-N-nitrosourea in a cDNA of the hprt gene

N-Methyl-N-nitrosourea (MNU) reacts with DNA to produce a varietyof lesions, of which O⁶-methylguanine (O⁶-MeG) has been implicatedin the mutagenic and carcinogenic effects of this agent. Thepresent study aimed to investigate the types and position specificitiesof mutations induced by MNU. Mutational sequence alterationswere determined for 53 independent mutations induced by MNUin a cDNA of the human hprt gene, which is stably integratedinto chromosomes of the mouse cell line VH12. The majority ofthe mutations induced by MNU were base substitutions (85%),mostly GC to AT transitions (41/43), and the remainder (15%)were frameshift or deletion mutations resulting from loss oraddition of a few bases. The transition mutations occurred preferentiallyat the middle G in 5'-purine-G-N-3' sequences in the non-transcribedstrand, and were distributed non-randomly over the coding regionof the gene. Analysis of the results suggests that, when interpretingmutational specificity and distribution, not only the natureof the mutational target sequence, but also the functional domainsof the protein should be considered.