Localization of a tumor suppressor gene associated with the progression of human breast carcinoma within a 1-cM interval of 8p22-p23.1

BACKGROUND

Frequent allelic losses on the short arm of chromosome 8 in several types of human cancers, and deletion maps of this region in tumor DNAs, have suggested that 8p harbors one or more genes that are important for suppressing tumorigenesis in the tissues in question.

METHODS

To define the locations of potential tumor suppressor genes involved in breast carcinoma, the authors examined 144 primary breast carcinomas for loss of heterozygosity at 18 highly polymorphic microsatellite loci on 8p. They also sought correlations between allelic loss on 8p and several clinicopathologic parameters.

RESULTS

Allelic loss was observed in 74 of the 144 sporadic breast carcinomas examined. Whereas more than half of the informative tumors showed loss of an allele at every locus on the short arm, 32 showed partial or interstitial deletions. Deletion mapping in this panel of tumors identified two distinct commonly deleted regions, one in a 1-cM interval flanked by D8S511 and D8S1991 at 8p22-p23.1, and the other in a 16-cM interval flanked by D8S136 and D8S1477 at 8p22-p21. Allelic losses in both of these regions were observed more frequently in tumors of the solid-tubular or scirrhous type than in less aggressive histologic types. Furthermore, allelic loss in either region occurred more frequently in larger and infiltrative tumors (T1 < T2 < T3).

CONCLUSIONS

The association of allelic losses on 8p with advanced tumor stage and aggressive histologic type implies that loss or inactivation of one of at least two putative tumor suppressor genes on 8p may contribute to the progression of breast carcinoma.

The effects of benzodiazepine (triazolam), cyclopyrrolone (zopiclone) and imidazopyridine (zolpidem) hypnotics on the frequency of hippocampal theta activity and sleep structure in rats

In order to investigate the relative efficacy and safety of zopiclone and zolpidem, we compared the effects of higher doses of zopiclone and zolpidem on the frequency of hippocampal theta activity and sleep structure with that of triazolam. Rats were divided into triazolam treatment group (1 mg/kg, 5 mg/kg), zopiclone treatment group (20 mg/kg, 100 mg/kg) and zolpidem treatment group (20 mg/kg, 100 mg/kg). Rats were injected intraperitoneally with these drugs or their vehicle. Polygraphic sleep recording and visual frequency analysis of the hippocampal EEG activity in REM sleep were carried out for 6 h after each injection. Zolpidem, unlike triazolam and zopiclone, had a much milder reducing-effect on the frequency of hippocampal theta activity and suppressing-effect on REM sleep. These results suggest that zolpidem may prove to be a safer hypnotic drug which has fewer or milder side effects than are benzodiazepine and cyclopyrrolone hypnotics.

[Effects of hemodialysis membrane on serum lipid profile of maintenance hemodialysis patients]

Atherosclerosis and lipid abnormalities are still insuperable complications for maintenance hemodialysis patients. We observed the serum lipid profile of 27 maintenance hemodialysis patients (M : F; 20 : 7, age; 54.9 +/- 6.2 y. o., hemodialysis duration; 10.8 +/- 4.9 years, body weight; 53.6 +/- 4.4 kg) using a low flux cellulose membrane, cellulose (1.5 m2), a vitamin-E-modified dialysis membrane, CL-15E (CL- 15E 1.5 m2, Terumo), and polysulfon, PS (PS-1.3UW 1.3 m2, Fresenius) dialysers. Each membrane dialyzer was used for 3 months. The blood flow rate was 200 ml/min, and hemodialysis time, 4 hours. When the dialyzers were replaced, fasting blood was collected at the beginning of hemodialysis and serum lipid parameters were measured. Seven additional maintenance hemodialysis patients were selected and TC, TG, HDL-C were measured as controls, because their dialyzers (low flux cellulose 1.5 m2) and hemodialysis conditions were not changed during the study. TC was decreased by PS and there were significant differences between cellulose and PS, and between CL-15E and PS. However, these changes were conducted within the normal range of TC. TG was not significantly changed during the study. HDL-C was decreased by CL-15E and PS as well as TC. There were significant differences in HDL-C between cellulose and CL-15E, and between cellulose and PS. Apo B, Apo B/A-I were decreased by PS and there were significant differences between cellulose and PS, respectively, LP(a) was not changed during the study. RLP-C (Cellulose vs. PS, CL-15E vs. PS), VLDL-C (Cellulose vs PS), and LDL-C (cellulose vs. PS, CL-15E vs. PS) were significantly decreased between membranes, respectively. Although the precise mechanism is yet unknown, the uptake of LDL and remnant into receptors of the liver might be improved by PS hemodialysis. In conclusion, these data suggest that PS decreased the serum levels of the lipid profile in maintenance hemodialysis patients and may be effective in improving their lipid abnormality.

Changes in morphology of neuroblastoma cells treated with all-trans retinoic acid combined with transfer of the C-terminal region of the amyloid precursor protein

Alzheimer disease is a progressive neurodegenerative disorder that is characterized by a loss of cognitive and memory functions. Amyloid fibrils deposited in neuritic plaque is mainly beta-amyloid protein (Abeta) that is derived from amyloid precursor protein (APP). The secreted form of APP, which is corresponded to N-terminal portion of APP, shows neurotrophic activities. On the other hand, Abeta and cytoplasmic domains of APP are thought to be neurotoxic. In order to investigate the effect of C-terminal fragment of APP covering Abeta and the cytoplasmic domain upon cell growth and differentiation, we established a stably transfected cell line producing the C-terminal 100 amino acid peptide of APR The transfected clones stained positively with anti-Abeta monoclonal antibody, TB-1. The growth rate of the transfected cells was not significantly different from that of mock-transfected cells or native NB39 cells. After treatment with all-trans retinoic acid (ATRA), mock-transfected cells extended neurite processes and showed neuronal-like differentiation, while a transfected clone overexpressing C-terminal fragment did not present neuronal-like morphology. These results suggest that ATRA-induced neurite extension may be suppressed by overexpression of the C-terminal fragment of APP.

Accumulation of alpha-synuclein/NACP is a cytopathological feature common to Lewy body disease and multiple system atrophy

Recently, we have shown that the precursor of the non-Abeta component of Alzheimer's disease amyloid (NACP), also known as alpha-synuclein, is a major component of Lewy bodies (LBs) as well as neuronal and glial cytoplasmic inclusions in multiple system atrophy (MSA). To elucidate whether the accumulation of NACP is specific to LB disease and MSA, we further studied 83 autopsied cases with various neurological disorders, using anti-NACP antibodies. In LB disease, NACP immunoreactivity was present in all of the LBs and Lewy neurites in both the central and peripheral nervous systems, the pale bodies in the substantia nigra, and dystrophic neurites in the hippocampal CA2/3 region. Immunoelectron microscopy revealed that the reaction product was localized within filamentous structures and associated granular structures. In MSA, NACP immunoreactivity was found in the intracytoplasmic inclusions of both neuronal and oligodendroglial cells, neuronal intranuclear inclusions, and swollen neuronal processes. No NACP immunoreactivity was found in a variety of other neuronal or glial inclusions in other disorders, including Alzheimer's disease, Pick's disease, progressive supranuclear palsy, corticobasal degeneration, motor neuron disease and triplet-repeat diseases. These findings strongly suggest that the accumulation of NACP is a cytopathological feature common to LB disease and MSA.

Increased telomerase activity in intrahepatic cholangiocellular carcinomas induced by N-nitrosobis(2-oxopropyl)amine in hamsters

Telomerase activities in intrahepatic cholangiocarcinomas induced by N-nitrosobis(2-oxopropyl)amine (BOP) in female hamsters were determined using a telomeric repeat amplification protocol (TRAP) assay followed by densitometric quantification. Each determination was repeated to confirm the results and telomerase activity was also detected by gel electrophoresis. An increase was evident in all of 10 cholangiocarcinomas examined, with levels ranging from 2.48 to 4.40 times the normal liver value by densitometric quantification. This finding of a consistent increase suggests that telomerase activation is involved in the development of intrahepatic cholangiocarcinomas and immortalization of cancer cells.

A novel member of the Ig superfamily, RPE7, expressed on the retinal pigment epithelial cell and Müller cell of the bovine retina

The retinal pigment epithelium of the vertebrate eye plays a major part in the maintenance of ocular function. To identify molecules involved in the exertion of their physiological functions, monoclonal antibodies against bovine retinal pigment epithelial cells were made. Analysis by immunofluoresence and immunoelectron microscopy showed that one of the monoclonal antibodies named anti-RPE7 stained the cell surface of retinal pigment epithelial cells and Müller cells. The anti-RPE7 antibody was revealed to recognize molecules of 45-55 kDa by Western blot analysis. Molecular cloning of the RPE7 cDNA and sequence analysis of the amino acids revealed that protein RPE7 belonged to the Ig superfamily. The high homology of RPE7 with metalloproteinase inducer suggests that the protein RPE7 might play a role in the matrix (interphotoreceptor matrix and basement membranes) remodeling as well as in retinal pigment epithelial cell migration under pathological conditions.

Immobilized liposome chromatography for studies of protein-membrane interactions and refolding of denatured bovine carbonic anhydrase

Small unilamellar vesicles (SUVs) composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and 1 mol% phosphatidylethanolamine were covalently coupled to chromatographic gel beads. Interactions of liposomal lipid bilayers with several water-soluble proteins, which had been denatured or partially denatured by 0.1-5 M guanidinium hydrochloride (GuHCl), were studied on gel beads containing the immobilized SUVs. The partially-denatured proteins treated with 0.5-1.0 M GuHCl were significantly retarded on the immobilized liposome column, whereas little retardation of native or unfolded proteins treated by >2 M GuHCl was observed on the same liposome columns. The retardation on the immobilized liposome column was found to be well correlated with local hydrophobicity, which was determined by the aqueous two-phase partitioning method using 1 mM Triton X-405 as a hydrophobic probe. It implies that the partially-denatured proteins are likely in a molten-globule state and associated with liposomal lipid bilayers. Chromatographic refolding of denatured bovine carbonic anhydrase (CAB) was achieved on the immobilized liposome column. The enzymatic activity of an unfolded CAB treated by 5 M GuHCl was recovered up to 83% after passing it through immobilized liposome column, whereas only 58% of the enzymatic activity was recovered when the denatured CAB was run on a liposome-free column. The refolding process is probably involved in the interaction of molten-globule state of CAB with the liposomal lipid bilayers.

Expression pattern of synucleins (non-Abeta component of Alzheimer's disease amyloid precursor protein/alpha-synuclein) during murine brain development

The non-Abeta component of Alzheimer's disease amyloid precursor protein (NACP) is predominantly a neuron-specific presynaptic protein that may play a central role in neurodegeneration because NACP fragments are found in Alzheimer's disease amyloid and a mutation in the NACP gene is associated with familial Parkinson's disease. In addition, NACP may play an important role during synaptogenesis and CNS development. To understand better the patterns of NACP expression during development, we analyzed the levels of this protein as well as the levels of another synaptic protein (synaptophysin) by ribonuclease protection assay, western blotting, and immunocytochemistry in fetal, juvenile, and adult mouse brain. From embryonic day 12 to 15, there was a slight increase, which was then followed by a more dramatic increase at later time points. Immunocytochemical staining for NACP increases throughout these stages as well. Although NACP appeared early in CNS development, synaptophysin levels started to rise at a later stage. These findings support the contention that NACP might be important for CNS development. Furthermore, the cytosolic component of NACP precedes the particulate component in development, indicating that a redistribution of the protein to the membrane fraction may be important for events later in neuronal development and in synaptogenesis.

Alpha-synuclein immunoreactivity in glial cytoplasmic inclusions in multiple system atrophy

Lewy bodies in Parkinson' s disease (PD) are strongly immunoreactive with antibodies against alpha-synuclein, which is mutated in some familial cases of the disease. We carried out immunohistochemical examinations of the brains of multiple system atrophy (MSA) patients using anti-alpha-synuclein antibodies. Strong alpha-synuclein immunoreactivity was found in glial cytoplasmic inclusions (GCIs), which are of oligodendroglial origin and occur exclusively in MSA. Alpha-synuclein-immunoreactive neuronal cytoplasmic inclusions (NCIs) were also found occasionally in the substantia nigra, pontine and inferior olivary nuclei, and dentate fascia. These findings indicate that alpha-synuclein is also a major component of GCIs and NCIs in MSA and strongly suggest that alpha-synuclein aggregation is a common process in certain neurodegenerative diseases, including PD and MSA.

Dynamic changes in glucose metabolism by lactate loading as revealed by a positron autoradiography technique using rat living brain slices

To demonstrate the preference of lactate over glucose as an energy substrate in normal brain tissue under normoxic condition, the dynamic changes in glucose uptake by lactate loading were investigated in living rat brain slices using a positron autoradiography technique. Fresh rat brain slices were incubated with [18F]2-fluoro-2-deoxy-D-glucose ([18F]FDG) in oxygenated Krebs-Ringer solution containing 10 mM glucose at 36 degrees C. During incubation, serial two-dimensional imaging of [18F]FDG uptake in the slices was constructed on the imaging plates. Lactate loading (20 mM) reversibly suppressed the [18F]FDG accumulation up to 80 min. Compared with the pre-loading and the unloaded control values, [18F]FDG uptake was suppressed to 25-45% in cerebral regions and 6-7% in cerebellum. The lactate concentration in the surrounding medium decreased after lactate loading. Hence brain tissue preferentially uses lactate over glucose under normoxic and euglycemic condition.

Rarity of PIT1 involvement in children from Russia with combined pituitary hormone deficiency

To ascertain the molecular background of combined pituitary hormone deficiency, screening for mutations in the pituitary-specific transcription factor (Pit-1/GHF-1) gene (PIT1) was performed on a cohort of 15 children from Russia with combined growth hormone (GH)/prolactin (Prl)/thyroid-stimulating hormone (TSH) deficiency. The group of patients, suspected of PIT1 mutations, consisted of four familial cases (seven patients) and eight sporadic cases. All had complete GH deficiency and complete or partial Prl and TSH deficiency. Direct sequencing of all six exons of PIT1 and its promoter region showed a C to T transition mutation at codon 14 of exon 1 in a 3 8/12-year-old girl. This novel PIT1 mutation results in a proline to leucine substitution (P14L). The patient was heterozygous for mutant and normal alleles. The heterozygous P14L mutation was also present in her mother as well as in her maternal aunt and grandmother, all of whom were phenotypically normal. There was no mutation in the father's DNA, suggesting the need for reevaluation of genomic imprinting. In other children of our series, no mutation in PIT1 or in its promotor region was identified. This is the first report on the analysis of PIT1 and its promoter region in Russian children with GH/Prl/TSH deficiency. However, as the involvement of PIT1 mutation is rare in Russia, the other negative cases need to be analyzed for another candidate gene responsible for combined GH/Pr/TSH deficiency.

High proportion of missense mutations of the BRCA1 and BRCA2 genes in Japanese breast cancer families

Mutations in either of two recently identified genes, BRCA1 and BRCA2, are thought to be responsible for approximately two-thirds of all cases of autosomal-dominantly inherited breast cancer. To examine the nature and frequency of BRCA1 and BRCA2 mutations in Japanese families exhibiting a high incidence of breast cancer, we screened 78 unrelated families in this category for mutations of these two genes. Examining the entire coding sequences as well as exon-intron boundaries of both genes by polymerase chain reaction (PCR) single-strand conformation polymorphism (SSCP) and multiplex-SSCP analysis, we identified possible disease-causing alterations in BRCA1 among affected members of 15 families and in BRCA2 in another 14 families. In 15 of those 29 families, the affected individuals carried missense mutations, although most germline mutations reported worldwide have been deletions or nonsense mutations. Our results, indicating that missense mutations of BRCA1 and BRCA2 tend to predominate over frameshifts or nonsense mutations in Japanese breast cancer families, will contribute significantly to an understanding of mammary tumorigenesis in Japan, and will be of vital importance for future genetic testing.

Cytologic diagnosis of signet-ring cell carcinoma of the breast

OBJECTIVE

To examine the cytologic features of signet-ring cell carcinoma (SRCC), defined as carcinoma dominated by signet-ring cells, of the breast and to discuss problems that occur in cytodiagnosis.

STUDY DESIGN

Five cases of SRCC of the breast were examined cytopathologically. Signet-ring cells were subclassified into intracytoplasmic lumina (ICL) type and non-ICL type. ICL type had large ICL containing mucin. Non-ICL-type cells had wide, amorphous cytoplasm diffusely dispersed with mucin.

RESULTS

In cases 1 and 2, fine needle aspiration biopsy (FNAB) revealed many signet-ring cells (non-ICL type), suggesting SRCC. Histologic diagnoses were ductal SRCC containing many signet-ring cells (non-ICL type). In cases 3 and 4, signet-ring cells (ICL type) were found sporadically among carcinoma cells without signet-ring features. Signet-ring cells were not regarded as the major component of the cells; thus, the cytologic diagnoses were lobular carcinoma, not otherwise specified. Pathologic diagnoses were lobular SRCC. Signet-ring cells were mostly ICL type. In case 5, most carcinoma cells on the smears showed signet-ring features (non-ICL type), suggesting SRCC. The histologic diagnosis was lobular SRCC, and signet-ring cells were mostly non-ICL type.

CONCLUSION

Ductal SRCC yielded more cellular smears as compared with lobular SRCC; therefore, cytologic diagnosis was easier in the former.

The incidence of subsequent endometrial carcinoma with tamoxifen use in patients with primary breast carcinoma

BACKGROUND

Tamoxifen commonly is used as adjuvant therapy for all stages of breast carcinoma. However, several studies have suggested an association between the use of tamoxifen in breast carcinoma patients and the subsequent development of endometrial carcinoma. The objective of this study was to determine the relation between long term tamoxifen usage and the risk of endometrial carcinoma in patients with breast carcinoma and to determine whether the increase in the cumulative incidence of endometrial carcinoma observed in previous studies is a true increase.

METHODS

Eight hundred and twenty-five patients with primary breast carcinoma who underwent annual gynecologic examination and cancer screening were reviewed. None of the patients had undergone hysterectomy or received any prior estrogen replacement therapy. These patients underwent a pelvic examination and cytologic and/or histologic screening of the cervix and endometrium every year even if they had no gynecologic symptoms. The dose of tamoxifen, length of tamoxifen treatment, and potential confounding variables were recorded. The relative risk of subsequent endometrial carcinoma in patients with primary breast carcinoma was analyzed by the Cox proportional hazards model.

RESULTS

Thirteen of the 825 patients developed a subsequent endometrial carcinoma. The cumulative incidence of endometrial carcinoma was 1.58%. Four of 13 patients who subsequently developed endometrial carcinoma received tamoxifen and 9 had not received tamoxifen. The relative risk of endometrial carcinoma by total dose of tamoxifen exposure was 1.0001 (P = 0.0145). There was no statistically significant correlation between the cumulative dose of tamoxifen or the length of tamoxifen treatment and the histologic type and grade of endometrial carcinoma. In addition, there was no statistical difference in the prognosis of endometrial carcinoma between the patients who received tamoxifen and patients who did not.

CONCLUSIONS

The results of this study show that tamoxifen use does not appear to increase the incidence of subsequent endometrial carcinoma in patients with primary breast carcinoma who underwent annual screening for gynecologic carcinoma.

Fabrication of a new substrate for atomic force microscopic observation of DNA molecules from an ultrasmooth sapphire plate

A new stable substrate applicable to the observation of DNA molecules by atomic force microscopy (AFM) was fabricated from a ultrasmooth sapphire (alpha-Al2O3 single crystal) plate. The atomically ultrasmooth sapphire as obtained by high-temperature annealing has hydrophobic surfaces and could not be used for the AFM observation of DNA. However, sapphire treated with Na3PO4 aqueous solution exhibited a hydrophilic character while maintaining a smooth surface structure. The surface of the wet-treated sapphire was found by x-ray photoelectron spectroscopy and AFM to be approximately 0.3 nm. The hydrophilic surface character of the ultrasmooth sapphire plate made it easy for DNA molecules to adhere to the plate. Circular molecules of the plasmid DNA could be imaged by AFM on the hydrophilic ultrasmooth sapphire plate.

[Relationship between DNA ploidy and survival in breast cancer]

The DNA ploidy pattern from fresh frozen specimens and survival rate was investigated in 91 primary breast cancers. Diploid patterns were found in 32 (35.2%) and aneuploid patterns in 59 (64.8%). The 5-year overall survival rate was significantly lower in aneuploid cases (76.3%) than diploid cases (93.8%) (p = 0.042), while there was no significant difference in disease-free survival between the two groups. there were negative nodes, no significant differences in 5-year overall or disease-free survival between patients with diploidy and aneuploidy. In contrast, when there were positive nodes, the 5-year overall and disease-free survival rates in patients with aneuploidy were 60.6% and 48.5%, which were significantly lower (p = 0.048 and p = 0.030) than the corresponding percentages of 92.3% and 84.6%, in those with diploidy. When the ploidy pattern was compared with other factors, a very close correlation was found between the ploidy pattern and histological grading (p < 0.0001). The ploidy pattern determined by flow cytometric DNA analysis may reflect the grade of malignancy of the breast cancer.

Mapping of a new target region of allelic loss to a 2-cM interval at 22q13.1 in primary breast cancer

Allelic losses on chromosome arm 22q are frequently observed in human meningiomas and in carcinomas of the colon, ovary, and breast. Among 140 primary breast cancers we examined for loss of heterozygosity (LOH) at 16 polymorphic loci on the long arm of chromosome 22, 56 (40%) showed LOH for at least one locus. Eleven of these tumors had retained heterozygosity for markers proximal to the NF2 locus but showed LOH for markers distal to NF2. Deletion mapping indicated a new common region of deletion, 2-cM in extent, at q13.1 between Interleukin 2 receptor beta (IL2RB) and D22S279. Our results raise the possibility that one or more tumor suppressor genes associated with breast cancer may exist at 22q13.1. Comparison of these results with clinicohistological data indicated that allelic losses on 22q tend to occur more frequently in tumors of malignant histological types.

Telencephalic ascending gustatory system in a cichlid fish, Oreochromis (Tilapia) niloticus

Central fiber connections of the gustatory system were examined in a percomorph fish Oreochromis (Tilapia) niloticus by means of the horseradish peroxidase (HRP), biocytin, and carbocyanine dye tracing methods. The primary gustatory areas in tilapia are the facial, glossopharyngeal, and vagal lobes of the medulla. The secondary gustatory nucleus (SGN) is a dumb-bell-shaped structure located in the isthmic region. In the SGN, there are two or three layers of neurons lining the ventromedial periphery of the nucleus and a molecular layer constituting of the major part of the nucleus. The SGN receives bilateral projections from the facial lobes and ipsilateral projections from the glossopharyngeal and vagal lobes. Ascending fibers originating from the SGN form the ipsilateral tertiary gustatory tract. A major part of the tract courses rostrally and terminates ipsilaterally in several diencephalic nuclei: the preglomerular tertiary gustatory nucleus (pTGN), the posterior thalamic nucleus, the nucleus diffusus lobi inferioris, the nucleus centralis of inferior lobe, and the nucleus recessus lateralis. The remaining small fiber bundle enters the medial and lateral forebrain bundles and terminates directly in two telencephalic regions; the area ventralis pars intermedia (Vi) and the area dorsalis pars posterior (Dp). Ascending fibers from the pTGN pass through the lateral forebrain bundle and terminate ipsilaterally in the dorsal region of area dorsalis pars medialis (dDm) of the telencephalon. Following biocytin injections into the dDm, small, round cells were labeled in the pTGN. After biocytin injections into the Vi and Dp of the telencephalon, retrogradely labeled cells were found in the ipsilateral SGN. The results show that the ascending fiber connections of the central gustatory system in the percomorph teleost tilapia are essentially similar to those of mammals. That is, the pathway from the primary gustatory areas (facial, glossopharyngeal, and vagal lobes) through the SGN and pTGN to the dDm in tilapia corresponds with the mammalian gustatory pathway from the solitary nucleus through the pontine taste areas (nucleus parabrachialis) and the thalamic relay nucleus (ventral posteromedial nucleus) to gustatory neocortices. In addition, the pathway from the primary gustatory areas through the SGN to the Vi and Dp in tilapia corresponds with the pathway from the solitary nucleus through the pontine taste areas to the amygdala in mammals.

Model system for heat-induced translocation of cytoplasmic beta-galactosidase across phospholipid bilayer membrane

The possibility of the translocation of the enzyme across the phospholipid bilayer membrane was investigated by using the liposomes prepared by 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) in which beta-galactosidase (beta-gal) was entrapped. Exposing the POPC liposomes entrapping beta-gal inside to heat treatment (40-50 degrees C, 1-60 min) was found to induce its translocation across the liposome membrane. The translocated activity of beta-gal from inner to outer aqueous phase of liposomes indicated the maximal value when the liposomes entrapping beta-gal were heated at 45 degrees C for 30 min. The gel permeation profiles of the liposomes before and after heat treatment (45 degrees C, 30 min) also supported the translocation of beta-gal across the liposome membrane. The membrane fluidity of liposomes was found to be increased with increasing temperature, so that the hydrophobicity of liposome membrane was also increased. The local hydrophobicity of beta-gal was maximized at the temperature of 40-50 degrees C. The mechanisms of beta-gal translocation have been suggested to be triggered by the enhancement of hydrophobic interaction between the liposome surface and beta-gal molecules. Finally, a minimal scheme of possible mechanism on the heat-induced translocation of beta-gal has been presented on the basis of the hydrophobic interaction between the liposome and the proteins. The experimental data on the heat-induced translocation of beta-gal were well corresponding to those from model calculation.

Allelic loss on chromosome 1p is associated with progression and lymph node metastasis of primary breast carcinoma

BACKGROUND

Frequent allelic losses on the short arm of chromosome 1 have been observed in a wide variety of human tumors. Cytogenetic and molecular genetic studies in breast carcinomas have shown frequent alterations on chromosome 1, involving loss of 1p or gain of 1q.

METHODS

To define the locations of tumor suppressor genes, 143 primary breast carcinomas were examined for allelic loss using 15 highly polymorphic microsatellite markers on 1p. Correlations also were sought between allelic loss on 1p and several clinicopathologic parameters.

RESULTS

Allelic loss was observed in 73 of the tumors (51%). Detailed deletion mapping identified target regions at 1p36, 1p34-p35, and 1p22-p31. Allelic losses at 1.36 or 1p34-p35 were observed more frequently in tumors of the solid tubular and scirrhous types than in less aggressive histologic types. Conversely, allelic loss at 1p22-p31 was correlated with lymph node metastasis and a tumor size > 2 cm.

CONCLUSIONS

Inactivation of tumor suppressor genes that lie in either 1p36 or 1p34-p35 might affect carcinogenic mechanisms in a histologic type specific manner, especially the solid tubular and scirrhous types. Alterations of one or more tumor suppressor genes at 1p22-p31 may play a role at late stages of breast carcinogenesis, especially with regard to local progression and lymph node metastasis.

Identification of a new commonly deleted region within a 2-cM interval of chromosome 11p11 in breast cancers

Allelic loss has been observed on the short arm of chromosome 11 in a variety of human cancers. We have examined 184 breast cancers for allelic loss anywhere in chromosome 11p, using 15 well-spaced microsatellite markers. Allelic loss was observed in 86 cases (47%) and a new commonly deleted region 2-cM in length was identified at 11p11 between loci D11S986 and D11S1313, in addition to a 12-cM region of a common deletion at 11p15.5. A significant association was found between allelic loss on 11p15.5 and LOH on 11p11 and the loss of progesterone receptors.

Single and repeated electroconvulsive shocks activate dopaminergic and 5-hydroxytryptaminergic neurotransmission in the frontal cortex of rats

1. The effect of electroconvulsive shock (ECS) on the extracellular concentration of dopamine (DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) was examined in the frontal cortex of rats with the use of in vivo microdialysis. 2. The extracellular concentration of DOPAC, HVA and 5-HIAA was largely increased after the first ECS treatment. The increase after the eighth ECS treatment tended to be attenuated or was significantly attenuated as compared to that after the first ECS treatment. The baseline concentration of DOPAC and 5-HIAA was significantly increased after repeated ECS, though that of DA and HVA did not show any significant change after repeated ECS. 3. These results suggest that the activating effect of repeated ECT on 5-hydroxytryptaminergic (5-HT) and DA neurotransmission, (especially on 5-HT neurotransmission), is significant in improving depression both in patients with Parkinson's disease (PD) and in those who do not suffer from PD.