A 3p21.3 region is preferentially eliminated from human chromosome 3/mouse microcell hybrids during tumor growth in SCID mice

We have previously shown that four markers spanning the 3p24-p21.3 region, THRB, AP20R, D3S1029, and D3S32, were regularly eliminated from three human chromosome 3 (chr3)/mouse microcell hybrids (MCHs) during tumor growth in SCID mice. In an attempt to narrow down the eliminated region, we have studied 22 new SCID mouse tumors derived from 5 MCH lines carrying human chr3. They were analyzed by fluorescence in situ hybridization (FISH), Southern blotting, and polymerase chain reaction (PCR). MCHs that carried human chr1, chr8, chr13, and chr17 were examined as controls. We could identify a common eliminated region (CER) at 3p21.3, bordered distally by D3S1260 and proximally by D3S643/D3F15S2. Eight of 53 chr3-specific PCR markers, AP20R, D3S966, D3S3559, D3S1029, Wl-7947, D3S2354, AFMb362wb9, and D3S32, were localized within the CER. This finding is consistent with the notion that a tumor suppressor gene may be located in this area, as suggested by frequent loss of heterozygosity (LOH) within this region observed in several types of solid tumors. Genes Chromosom. Cancer 18:200–211, 1997. © 1997 Wiley-Liss, Inc.     

Human/mouse microcell hybrid based elimination test reduces the putative tumor suppressor region at 3p21.3 to 1.6 cM

We have previously identified an approximately 7 cM long common eliminated region (CER), involving the 3p21.3 markers AP20R, D3S966, D3S3559, D3S1029, WI-7947, D3S2354, AFMb362wb9, and D3S32, in human chromosome 3/A9 mouse fibrosarcoma microcell hybrid (MCH) derived SCID mouse tumors. We now report the results of our more detailed analysis on 24 SCID mouse tumors derived from two MCH lines that originally carried intact human chromosomes 3. They were analyzed by fluorescence in situ hybridization (FISH) painting and PCR, using 24 markers covering the region between D3S1611 and D3S1235 at 3p22-p21.2. D3S32 and D3S2354 were regularly eliminated during in vivo tumor growth, whereas the other 22 markers, D3S1611, ACAA, D3S1260, WI-692, AP20R, D3S3521, D3S966, D3S1029, D3S643, WI-2420, MST1, GNAI2, D3S1235, D3S1298, GLB1, WI-4193, D3S3658, D3S3559, D3S3678, WI-6400, WI-7947, and WI-10865, were regularly retained. We have defined a common eliminated region of approximately 1.6 cM (designated as CER1) inside the 7 cM CER described earlier. CER1 is flanked distally by D3S1029 and proximally by D3S643. Genes Chromosomes Cancer 20:329–336, 1997. © 1997 Wiley-Liss, Inc.     

LTBP-2 confers pleiotropic suppression and promotes dormancy in a growth factor permissive microenvironment in nasopharyngeal carcinoma

This study identified LTBP-2 as a pleiotropic tumor suppressor in nasopharyngeal carcinoma, which safeguards against critical malignant behaviors of tumor cells. LTBP-2 expression was significantly decreased or lost in up to 100% of NPC cell lines (7/7) and 80% of biopsies (24/30). Promoter hypermethylation was found to be involved in LTBP-2 silencing. Using a tetracycline-regulated inducible expression system, we unveiled functional roles of LTBP-2 in suppressing colony formation, anchorage-independent growth, cell migration, angiogenesis, VEGF secretion, and tumorigenicity. Three-dimensional culture studies suggested the involvement of LTBP-2 in maintenance of tumor cell dormancy in a growth factor favorable microenvironment.     

Implementation of an image-guided radiation therapy program: Lessons learnt and future challenges

The aim of this paper is to detail the experience obtained in implementing an image-guided radiation therapy program at the Northern Sydney Cancer Centre. This required retrofitting a Varian Clinac 21EX with an on-board imager. The commissioning and quality assurance procedures, organisation of a multidisciplinary image guided radiation therapy group, and the development of clinical protocols for orthogonal kV and cone beam computed tomography implementation are described. Reassessment of the image-guided radiation therapy program has continued as new equipment and software versions were made available in the department.     

水体中克雷伯菌属的分布及其在水源性急性肠道感染中的价值

俄罗斯不同气候地区不同功能水体中克雷伯菌属广泛分布。克雷伯菌属可见于遭受生物、化学污染的集中供水的地表水源,无防护的地下蓄水层,缺乏有效清洁、消毒系统的饮用水。研究表明,水体中的克雷伯菌属具有致病性和毒性,对现代药物和消毒剂(氯、紫外线)具有抗性,很容易穿透进入地下蓄水层。克雷伯菌属细菌有很强的致病性(粘附力、侵袭力、磷酸酯酶、卵磷脂酶、脱氧核糖核酸酶、溶血活性),含有致病性遗传标记cnf-1。克雷伯菌属(100 CFU/dm³)可引起急性肠道感染。在不检测总大肠菌群的情况下,检测水体尤其是饮用水中的克雷伯菌属,可以评估所用水的流行病学危险。     

Radiobiological Studies of Human Hybrid Cells (Skin Fibroblasts × HeLa) and Their Tumourigenic Segregants

Summary

Data are presented on the survival characteristics following γ-irradiation of a human hybrid cell line (skin fibroblasts × HeLa), and its tumourigenic segregant, which indicate that transition from the non-tumourigenic to the tumourigenic state is associated with a decrease in the ability to accumulate and repair sublethal damage. Previous studies have demonstrated that this transition to the tumourigenic state is also associated with loss of specific chromosomes (one copy each of chromosomes 11 and 14). It is suggested that this loss of chromosomes may account for the change in radiosensitivity.     

Dentists' attitudes and practice regarding smoking

Dentists are a potentially valuable source of community education about the health effects surrounding tobacco use. The aims of this study were to provide Australian data on dentists' current practice regarding discussing smoking with patients, dentists' perceptions of the barriers to discussing smoking with patients and dentists' interest in discussing smoking with patients. A postal survey of all dentists who were members of the Hunter Branch of the Australian Dental Association in New South Wales was conducted. Dentists generally reported quite high levels of current activity regarding smoking. The majority of dentists reported asking at least some of their patients whether or not they smoked. Dentists reported that they discussed the possible oral effects of smoking with at least some of their smoking patients. Furthermore, they told at least some of their patients with smoking related disease that smoking may have contributed to their problems. Dentists identified a number of difficulties involved in helping patients quit smoking. These findings may be used to help guide future research and practice in involving dentists further in discussing smoking with patients.     

Minimally invasive off-pump pulmonary embolectomy

We report the case of a 35-year-old female with acute massive right pulmonary embolism, successfully treated by a minimally invasive off-pump pulmonary embolectomy-the first case in the literature implemented via the J-ministernotomy.     

Cancer stem cells contribute to cisplatin resistance in Brca1/p53-mediated mouse mammary tumors

The majority of BRCA1-associated breast cancers are basal cell-like, which is associated with a poor outcome. Using a spontaneous mouse mammary tumor model, we show that platinum compounds, which generate DNA breaks during the repair process, are more effective than doxorubicin in Brca1/p53-mutated tumors. At 0.5 mg/kg of daily cisplatin treatment, 80% primary tumors (n = 8) show complete pathologic response. At greater dosages, 100% show complete response (n = 19). However, after 2 to 3 months of complete remission following platinum treatment, tumors relapse and become refractory to successive rounds of treatment. Approximately 3.8% to 8.0% (mean, 5.9%) of tumor cells express the normal mammary stem cell markers, CD29(hi)24(med), and these cells are tumorigenic, whereas CD29(med)24(-/lo) and CD29(med)24(hi) cells have diminished tumorigenicity or are nontumorigenic, respectively. In partially platinum-responsive primary transplants, 6.6% to 11.0% (mean, 8.8%) tumor cells are CD29(hi)24(med); these populations significantly increase to 16.5% to 29.2% (mean, 22.8%; P < 0.05) in platinum-refractory secondary tumor transplants. Further, refractory tumor cells have greater colony-forming ability than the primary transplant-derived cells in the presence of cisplatin. Expression of a normal stem cell marker, Nanog, is decreased in the CD29(hi)24(med) populations in the secondary transplants. Top2A expression is also down-regulated in secondary drug-resistant tumor populations and, in one case, was accompanied by genomic deletion of Top2A. These studies identify distinct cancer cell populations for therapeutic targeting in breast cancer and implicate clonal evolution and expansion of cancer stem-like cells as a potential cause of chemoresistance.