Loss of p53 protein during radiation transformation of primary human mammary epithelial cells

The causative factors leading to breast cancer are largely unknown. Increased incidence of breast cancer following diagnostic or therapeutic radiation suggests that radiation may contribute to mammary oncogenesis. This report describes the in vitro neoplastic transformation of a normal human mammary epithelial cell strain, 76N, by fractionated gamma-irradiation at a clinically used dose (30 Gy). The transformed cells (76R-30) were immortal, had reduced growth factor requirements, and produced tumors in nude mice. Remarkably, the 76R-30 cells completely lacked the p53 tumor suppressor protein. Loss of p53 was due to deletion of the gene on one allele and a 26-bp deletion within the third intron on the second allele which resulted in abnormal splicing out of either the third or fourth exon from the mRNA. PCR with a mutation-specific primer showed that intron 3 mutation was present in irradiated cells before selection for immortal phenotype. 76R-30 cells did not exhibit G1 arrest in response to radiation, indicating a loss of p53-mediated function. Expression of the wild-type p53 gene in 76R-30 cells led to their growth inhibition. Thus, loss of p53 protein appears to have contributed to neoplastic transformation of these cells. This unique model should facilitate analyses of molecular mechanisms of radiation-induced breast cancer and allow identification of p53-regulated cellular genes in breast cells.

Cloning, sequencing and expression of the gene encoding NADH oxidase from the extreme anaerobic thermophile Thermoanaerobium brockii

The gene encoding the enzyme NADH oxidase from the extreme thermophile Thermoanaerobium brockii has been isolated from a recombinant library of genomic DNA and sequenced. An open reading frame corresponds to the 651 amino acids of the enzyme's subunit, which include characteristic FAD- and NADH-binding sequences, as well as cysteines which are involved in the FeS cluster present in the enzyme. The enzyme is expressed either from its own promoter or from vector promoters in Escherichia coli. After heat-treating the recombinant extracts at 70 degrees C, most of the host proteins are denatured, leaving the NADH oxidase 5- to 10-fold enriched.

Characteristics of the epitope of protein-reactive anti-peptide antibodies

The specificity of hen egg-white lysozyme (HEL)-reactive rabbit antibodies induced by the peptide loop I.II (sequences 57-107 containing Cys64-Cys80 and Cys76-Cys94) of HEL was clarified by analyzing their cross-reactions with various avian lysozymes and their reaction with synthetic peptides (sequences 59-82) in which alanine was substituted for the amino acid at certain positions. The Arg-68 residue of HEL plays a dominant role in the binding, while Gly-71, Ser-72, Arg-73, and Pro-79 also contribute to the binding of two anti-Ploop I.II antibodies (rabbit number 125 and 126). These residues, although remote in sequence, are grouped together in the crystal structure of HEL and may form an area of contact with the antibody. Contributions by Trp-63, Ile-78, and Asn-77 to the binding of the two antibodies to HEL were excluded. These results support the idea that the anti-Ploop I.II antibodies recognize a conformational type of epitope which is similar to that of native HEL. The immunogenicity of the reduced and alkylated form of Ploop I.II was also tested, but it failed to induce an HEL-reactive antibody.

[Effects of stimulation of SI cortex and cerebral peduncle on the nociceptive responses of spinal dorsal horn neurons in the rat]

Single spinal dorsal horn neurons were recorded extracellularly with glass micropipettes, and the effect of stimulation of SI cortex or cerebral peduncle (CP) was observed on the long latency discharges (C-fiber evoked response) of the wide dynamic range (WDR) neurons induced by intense electrical skin stimulation. Inhibition was the predominant effect of SI cortex stimulation on the C-fiber evoked responses of WDR neurons. The effect of CP stimulation was similar to that of SI cortex stimulation, except that the former was much more effective than the latter. The inhibition lasted a period of time varying from 400 ms to more than 10 min after CP stimulation in different neurons. Systemic naloxone had no significant effect on the inhibition produced by CP stimulation. Systemic methysergide reduced or eliminated the inhibition in a part of the neurons tested, suggesting that 5-HT, but not opioid peptides, is involved partially in mediation of the descending inhibitory effect originating from the cortex.

[Histochemical study of intrinsic laryngeal muscles in neonates]

The motor end-plates and muscle fiber types in muscles of cricothyroid, posterior cricoarytenoid, thyroarytenoid were in five neonates and two adults studied by staining with acetylcholinesterase (AChE) and succinic dehydrogenase (SDH). The muscle fibers in neonate could be classified into three types: red, white and intermediate. The diameters of muscle fibers were different, with the white muscle fiber widest and the red ones narrowest. Each of the laryngeal muscles was composed of three muscle types in proportion. The motor end-plate showed a concentrated distribution band.

Growth of an androgen-sensitive human prostate cancer cell line, LNCaP, in nude mice

This study was undertaken to establish an androgen-sensitive model of human prostatic carcinoma in nude mice. The androgen-sensitive prostatic carcinoma cell line, LNCaP, was suspended in reconstituted basement membrane (Matrigel) and injected subcutaneously into nude mice. The LNCaP cell line was chosen for the study, because the cell line is androgen-sensitive and secretes prostate specific antigen (PSA) into culture media. Following injection of 1 x 10(6) LNCaP cells with 0.25 ml of Matrigel, 88% of mice exhibited palpable tumor burdens after 12 weeks of observation. In addition, significant levels of PSA were observed in the serum of LNCaP-bearing mice. Bilateral orchiectomy of mice resulted in tumor regression and stabilization of serum PSA levels, compared to testis-intact controls. A significant correlation of PSA to tumor volume and weight was observed. The castrate level of testosterone was confirmed by radioimmunoassay and was similar to testosterone levels in female nude mice. Matrigel allows for a conducive environment to propagate LNCaP cells in nude mice. Furthermore, the growth can be manipulated by castration, leading to involution of tumor and stabilization of serum PSA level. This in vivo model of hormone-sensitive human prostate cancer cell line will serve as a model for the study of prostate tumor biology and treatment.

A thermostable NADH oxidase from anaerobic extreme thermophiles

A high-abundance NADH-oxidizing enzyme (NADH: acceptor oxidoreductase, EC 1.6.99.3) has been identified and isolated from a range of anaerobic extreme thermophiles, including strains of Clostridium thermohydrosulfuricum and Thermoanaerobium brockii. By use of a pseudo-affinity salt-promoted adsorbent, a nearly pure sample was obtained in one step; remaining impurities were separated by ion-exchange. The fully active purified enzyme contains FAD (two molecules per subunit of 75-78 kDa) and iron-sulphur, and is hexameric in its most active form. The reaction with oxygen is a one- or two-electron transfer to produce superoxide radical and H2O2; other acceptors include tetrazolium salts, dichlorophenol-indophenol, menadione and ferricyanide. The role of the enzyme is not clear; it was found not to be NAD:ferredoxin oxidoreductase, which is a major NADH-utilizing enzyme in these organisms.

Cloning, sequencing, and expression of the Zymomonas mobilis fructokinase gene and structural comparison of the enzyme with other hexose kinases

The frk gene encoding the enzyme fructokinase (fructose 6-phosphotransferase [EC 2.7.1.4]) from Zymomonas mobilis has been isolated on a partial TaqI digest fragment of the genome and sequenced. An open reading frame of 906 bp corresponding to 302 amino acids was identified on a 3-kbp TaqI fragment. The deduced amino acid sequence corresponds to the first 20 amino acids (including an N-terminal methionine) determined by amino acid sequencing of the purified protein. The 118 bp preceding the methionine codon on this fragment does not appear to contain a promoter sequence. There was weak expression of the active enzyme in the recombinant Escherichia coli clone under control of the lac promoter on the pUC plasmid. Comparison of the amino acid sequence with that of the glucokinase enzyme (EC 2.7.1.2) from Z. mobilis reveals relatively little homology, despite the fact that fructokinase also binds glucose and has kinetic and structural properties similar to those of glucokinase. Also, there is little homology with hexose kinases that have been sequenced from other organisms. Northern (RNA) blot analysis showed that the frk transcript is 1.2 kb long. Fructokinase activity is elevated up to twofold when Z. mobilis was grown on fructose instead of glucose, and there was a parallel increase in frk mRNA levels. Differential mRNA stability was not a factor, since the half-lives of the frk transcript were 6.2 min for glucose-grown cells and 6.6 min for fructose-grown cells.

The weaver gene encodes a nonautonomous signal for CNS neuronal differentiation

In the neurological mutant mouse weaver, CNS precursor cells in the external germinal layer (EGL) of the cerebellar cortex proliferate normally, but fail to differentiate and die in the proliferative zone. To examine the autonomy of expression of the weaver gene, we carried out cell-mixing experiments in vitro. In homotypic, reaggregate cultures, weaver EGL precursor cells expressed the general neuronal markers N-CAM, L1, and MAP2, but failed to express the late neuronal antigens TAG-1 and astrotactin, to extend neurites or to migrate on glial fibers. After reaggregation with wild-type EGL precursor cells, weaver precursor cells extended neurites equivalent in length to wild-type cells, migrated along astroglial fibers, and expressed TAG-1 and astrotactin. Rescue of neurite production was also achieved by the addition of membranes from, but not by medium conditioned by wild-type cells. These findings suggest that the weaver gene acts non-autonomously, encoding a membrane-associated ligand that induces EGL neuronal differentiation.

Changes in serum osmolality and osmolar discrepancy in burned patients

Forty-three patients with burns of various depth and burn surface area were studied to determine the relationship between burn severity and changes of serum osmolality. The results showed that the osmolality in four patients who died were significantly higher than the osmolalities of survivors with very serious burns, whose osmolalities decreased gradually to normal level. Hyperosmolality and obvious osmolar discrepancy often co-exist. It is suggested that the changes of osmolality and osmolar discrepancy can reflect the burn severity and prognosis of the patients.

Shared idiotype expression by chronic lymphocytic leukemia and B-cell lymphoma

Antiidiotype (Id) antibodies identify unique determinants within the surface immunoglobulin (Ig) that are present on B-cell tumors. Anti-Ids have been used for diagnosis and therapy of B-cell lymphoma and leukemia. A panel of 29 anti-Id monoclonal antibodies (MoAbs) that recognize shared idiotypes (SIds) on B-cell lymphomas was tested for reactivity with both B-cell leukemias and lymphomas. Ten of 40 (25%) cases of chronic lymphocytic leukemia (CLL) reacted with at least one of the 29 anti-SId MoAbs. Three cases reacted with more than one anti-SId MoAb, but there was no repetitive pattern of a single anti-SId MoAb reacting with a large proportion of CLL cases. In contrast, for B-cell lymphoma, in which 11 of 31 (36%) cases reacted, one anti-SId (B4-1) reacted with five of the positive cases; all were diffuse histology. Restricted anti-SId reactivity may lead to important insights into the etiology of certain B-cell lymphomas. In addition, these anti-SIds may obviate the need to develop "tailor-made" antibodies for individual patients.

[Genotoxicity of fried fish extract, MeIQ and inhibition by green tea antioxidant]

Fried fish extract (FFE) and its related compound MeIQ showed potent genotoxicity to mammalian cells. FFE and MeIQ induced an increase in SCE or micronuclei in V79 cells in the presence of S9mix and an increase in SCE in IAR20 cells without S9mix UDS of rat primary hepatocytes was also significantly increased after treatment by FFE or MeIQ. Green tea antioxidant strongly inhibited the increase in SCE and micronuclei induced by FFE or MeIQ in V79 or IAR20 cells. The inhibitory effect of antioxidant on UDS was also observed in rat primary hepatocytes treated with FFE or MeIQ. The results indicate that mutagens and/or carcinogens might be produced during cooking of meat under high temperature. Frequent intake of green tea might be beneficial to human health.

The histochemical study of rat sciatic nerve cholinesterase in degeneration and regeneration

With a modified, less time-consuming, Karnovsky-Roots method, this study evaluated the reduction and recovery of rat sciatic nerve cholinesterase (ChE) in degeneration and regeneration. Characteristics of motor fascicles included not only partial staining of acetylcholinesterase (AchE) in the axon, but also a small amount of more intense staining of butyrylcholinesterase (BuchE) in the unmyelinated fibers, scattered between the myelinated fibers in a spot or fleck form. Characteristics of sensory fascicles included more intense staining of BuchE in the unmyelinated fibers, (appearing as irregular balls or pieces), and a scattering between unstained myelinated fibers. Mixed fascicles had characteristics of both motor and sensory fascicles. Unmyelinated fibers exhibited BuchE activity, but myelinated fibers exhibited AchE activity. Preparation time for a specimen to react to ChE-positive staining was about 1 to 2 hr; the method is very suitable for diagnosis during surgery. After nerve transection, AchE activity at the distal nerve end began to reduce gradually; no AchE could be tested after two weeks. But BuchE activity in unmyelinated fibers could be found until 30 days after transection. After epineurial suturing of the peripheral nerve transection, new AchE activity could be found at the anastomosis site until about two weeks and at 1 cm distal to the anastomosis site until about three weeks. It became more intense with the passage of time and, at about six weeks, regenerated AchE-positive myelinated fibers could be seen at the distal end of the nerve.

[Primary nephrotic syndrome associated with renal tubular dysfunctions: renal morphologic alteration and response to treatment]

To evaluate the importance of renal tubular dysfunctions (RTD) in the patients with primary nephrotic syndrome (NS), renal tubular functions tests and renal biopsies were taken in 25 cases with NS. They were divided into two groups: A. with RTD (15 cases); B. without RTD (10 cases). Four glomerular pathological types were found in 22 cases: 15 cases with MePGN, 2 cases with IgAN, 4 cases with MPGN, 1 case with SGN. Degrees of pathological alteration of renal tubules were as follows: 5 cases in grade 0, all from group B. 11 cases in grade I, 7 belong to group A and 4 to group B. Each 3 cases in Grade II and grade III, all of them from group A. Treatment with steroids and cyclophosphane resulted in complete remission in 1 case and no effect in 11 cases of group A, and complete remission in 6 cases and no effect in 3 cases of group B. NS associated with RTD is common in adults, and its major clinical characteristic is resistant to steroid therapy. RTD is closely related to renal tubular morphological changes, and is not related to pathological classification of glomerular alteration.

[The effect of aflatoxin B1 on vitamin A status and on microsomal mixed function oxidase in male mouse]

Thirty healty male mice were divided into two groups. One group received oral dose of AFBi (900 micrograms/kg) for seven days and another the same amount of solvent in the same way during this period. AFB1 significantly decreased the content of VitA in the serum and liver, respectively, 60% and 36% less than that of the control, while it increased the content in kidney, 33% more than that of the control. AFB1 markedly induced hepatic microsomal cytochrome P450 and the concentration of cytochrome P450 increased 43%. But no effect was found in the activity of hepatic microsomal NADPH cytochrome P450 reductase by AFB1. The experimental results show that AFB1 can reduce the level of VitA in vivo and this effect on VitA is correlative with induction of hepatic microsome cytochrome P450.

[Preliminary study on mutagenicity of MeIQ and extracts of fried fish and antimutagenicity of some dietary factors]

2-amino-3,4-dimethylimidazo (4,5-f) quinoline (MeIQ) and extracts of fried fish showed a strong mutagenicity as reflected backward mutation in Salmonella typhimurium. Significant inhibitory effects on mutagenicity induced by MeIQ or extracts of fried fish were found by simultaneous treatment with extracts of fresh vegetables, fruits and especially green tea antioxidants. The results indicated that some mutagens and/or carcinogens might be produced during high temperature cooking of some animal meats. The frequent intake of fresh vegetables, fruits and green tea might be beneficial in the prevention of human cancer.

Aircraft noise-induced temporary threshold shift

Audiograms were taken on 20 young men before and immediately after exposure to Fighter-6 ground running-up noise, and their course of recovery was followed. The sound levels at the engine hatch were 117-128 dB(A). The noise-induced temporary threshold shift was more than 13 dB. The maximum threshold shift occurred at 4 kHz. The shift in the low and speech frequencies recovers more rapidly and is completed in 30 min, whereas that in the high-frequency range recovers much more slowly, not returning to normal until 24 h later. High-frequency hearing loss is at risk in groundcrew. In order to prevent hearing damage, they ought to wear ear-protectors. We discovered that the V-shaped depression was not at 4 kHz but at 6 kHz. The former view concerning the pathogenesis of "4 kHz depression", therefore, is open to question. This interesting subject warrants further study.

The effects of high iodine on the brain development of mice

C57 mice were divided into two groups: (A): experiment group (H group). Each female mouse was injected with 20 microliter iodized oil; (B): control group (N group). Both groups were mated 8 days after iodized oil injection. Urine iodine contents/24 h of H group was 20 times higher than that in N group 7 days after injection and 18 times higher two months later. Serum T4 values were determined. Brain protein, DNA, body weight, motility and learning ability were measured in the progeny. The results indicate that there was no statistically significant difference between the groups in any of the parameters mentioned above. This strongly suggests that a high iodine dose, given as iodized oil, does not have obvious damaging effects on brain development, at least in mice.

[Treatment of primary carcinoma of the gallbladder--report of 33 cases]

33 cases of primary carcinoma of the gallbladder confirmed by operation from 1962 to 1983 are reported. It comprises 2.7% of all patients undergoing cholecystectomy during the same period. One was diagnosed preoperatively. The lesions were resected in 17 (51.5%), of which 12 were associated with gallstones, and survived for an average of 21 months, while those unresected survived for 3 months. The overall 5-year survival rate was 4.5%. The correlation of the gallbladder cancer with cholecystitis, gallstones and other related organic changes is discussed. The diagnosis is difficult and prognosis remains poor unless the cancer is diagnosed by operation at early stage. For this reason, it is suggested that preventive cholecystectomy on elderly patients with cholecystitis and gallstones be likely to lead to better results.