Blonanserin reverses the phencyclidine (PCP)-induced impairment in novel object recognition (NOR) in rats: role of indirect 5-HT(1A) partial agonism.

Blonanserin is an atypical antipsychotic drug (APD) which, compared to other atypical APDs, is a relatively selective serotonin (5-HT)2A and dopamine D2 antagonist. Comparing blonanserin with more broadly acting atypical APDs could be useful to test the contributions of actions at other monoamine receptors, e.g. 5-HT1A receptors, to the reversal of PCP-induced novel object recognition (NOR) deficit. In this study, we tested the effect of blonanserin alone, and in combination with 5-HT1A agents, on NOR deficit induced by subchronic treatment with the N-methyl-D-aspartate (NMDA) receptor antagonist, phencyclidine (PCP; 2 mg/kg), b.i.d., for 7 days. Blonanserin, 1mg/kg, but not 0.3mg/kg, improved the PCP-induced NOR deficit. However, at 1mg/kg, object exploration was diminished. Co-administration of sub-effective doses of blonanserin (0.3 mg/kg) and the 5-HT1A partial agonist, tandospirone (0.2 mg/kg), significantly reversed the NOR deficit without diminishing activity during the acquisition or retention periods. The combination of WAY100635 (0.6 mg/kg), a 5-HT1A antagonist, and blonanserin (1 mg/kg), also diminished object exploration which prevented assessment of the effect of this combination on NOR. WAY100635 (0.6 mg/kg) blocked the ameliorating effect of risperidone (0.1 mg/kg), another atypical APD with low affinity for 5-HT1A receptors, but did not impair exploration. These results suggest that blonansein and risperidone, atypical APDs which lack a direct action on 5-HT1A receptors require 5-HT1A receptor stimulation to reverse the subchronic PCP-induced NOR deficit and provide a support for clinical trial of blonanserin in combination with tandospirone to ameliorate cognitive impairment in schizophrenia and to have fewer side effects.

Downregulation of Ral GTPase-activating protein promotes tumor invasion and metastasis of bladder cancer.

The small GTPase Ral is known to be highly activated in several human cancers, such as bladder, colon and pancreas cancers. It is reported that activated Ral is involved in cell proliferation, migration and metastasis of bladder cancer. This protein is activated by Ral guanine nucleotide exchange factors (RalGEFs) and inactivated by Ral GTPase-activating proteins (RalGAPs), the latter of which consist of heterodimers containing a catalytic α1 or α2 subunit and a common ß subunit. In Ras-driven cancers, such as pancreas and colon cancers, constitutively active Ras mutant activates Ral through interaction with RalGEFs, which contain the Ras association domain. However, little is known with regard to the mechanism that governs aberrant activation of Ral in bladder cancer, in which Ras mutations are relatively infrequent. Here, we show that Ral was highly activated in invasive bladder cancer cells due to reduced expression of RalGAPα2, the dominant catalytic subunit in bladder, rather than increased expression of RalGEFs. Exogenous expression of wild-type RalGAPα2 in KU7 bladder cancer cells with invasive phenotype, but not mutant RalGAPα2-N1742K lacking RalGAP activity, resulted in attenuated cell migration in vitro and lung metastasis in vivo. Furthermore, genetic ablation of Ralgapa2 promoted tumor invasion in a chemically-induced murine bladder cancer model. Importantly, immunohistochemical analysis of human bladder cancer specimens revealed that lower expression of RalGAPα2 was associated with advanced clinical stage and poor survival of patients. Collectively, these results are highly indicative that attenuated expression of RalGAPα2 leads to disease progression of bladder cancer through enhancement of Ral activity.

Serotonin receptors as targets for drugs useful to treat psychosis and cognitive impairment in schizophrenia.

The concept that the efficacy of all antipsychotic drugs (APDs) can be explained by their action on dopamine (DA) D2 receptors is most challenged by drugs such as clozapine which target serotonin (5-HT)2A receptors as an essential component of their efficacy and tolerability. The 5-HT2A receptor, along with 5-HT1A, 5-HT 2C, 5-HT 6 or 5-HT 7 receptors, all of which are components of the mechanism of action of clozapine, represent important targets for treating multiple aspects of schizophrenia, especially psychosis and cognitive impairment. The class of atypical antipsychotic drugs (APDs), of which clozapine is the prototype, share in common more effective 5-HT 2A receptor inverse agonism and weaker interference with D2 receptor stimulation, either through D2 receptor blockade or partial D2 receptor agonism. This has led to development of a selective 5-HT2A antagonist, ACP-103 (pimavanserin), which has been found to be effective as monotherapy in L-DOPA psychosis and has promise as an add-on agent for sub-effective doses of atypical APDs. We review here the extensive preclinical evidence to support the importance of 5-HT2A receptor inverse agonism to the action of clozapine and related atypical APDs, and evidence supporting the potential of selective 5-HT2A, 5-HT 6 , and 5-HT 7, antagonists, 5-HT1A partial agonists and 5-HT2C agonists for development of drugs which ameliorate psychosis or cognitive impairment.

The role of 5-HT1A receptors in phencyclidine (PCP)-induced novel object recognition (NOR) deficit in rats.

RATIONALE: Atypical antipsychotic drugs (APDs), many of which are direct or indirect serotonin (5-HT)(1A) agonists, and tandospirone, a 5-HT(1A) partial agonist, have been reported to improve cognition in schizophrenia. OBJECTIVES AND METHODS: We tested the effect of 5-HT(1A) agonism, alone, and in combination with other psychotropic agents, including the atypical APD, lurasidone, in reversing the deficit in novel object recognition (NOR) induced by subchronic treatment with the non-competitive NMDA receptor antagonist, phencyclidine (PCP) (2 mg/kg, b.i.d., for 7 days). RESULTS: Subchronic treatment with PCP induced a persistent NOR deficit. Lurasidone (0.1 mg/kg), a potent 5-HT(1A) partial agonist, 5-HT(2A) antagonist, and weaker D(2) antagonist, tandospirone (0.6 mg/kg), and the selective post-synaptic 5-HT(1A) agonist, F15599 (0.16 mg/kg), ameliorated the subchronic PCP-induced-NOR deficit. The 5-HT(1A) antagonist, WAY100635 (0.6 mg/kg), blocked the ameliorating effects of tandospirone and lurasidone. The combination of sub-effective doses of tandospirone (0.2 mg/kg) and lurasidone (0.03 mg/kg) also reversed the PCP-induced NOR-deficit. Buspirone, a less potent partial 5-HT(1A) agonist than tandospirone, was less effective. Co-administration of tandospirone (0.2 mg/kg) and pimavanserin (3 mg/kg), a relatively selective 5-HT(2A) receptor inverse agonist, did not reverse the effect of sub-chronic PCP on NOR. The D(2) antagonist, haloperidol, blocked the ameliorating effect of tandospirone on the PCP-induced deficit in NOR. CONCLUSIONS: These results indicate that 5-HT(1A) agonism is adequate to ameliorate the PCP-induced impairment in NOR and suggest further study of utilizing the combination of a 5-HT(1A) agonist and an atypical APD to ameliorate some types of cognitive impairment in schizophrenia.

Antihypertensive effect of a fixed-dose combination of losartan/hydrochlorothiazide in patients with uncontrolled hypertension: a multicenter study.

BACKGROUND: Achieving adequate blood pressure (BP) control often requires more than one antihypertensive agent. The purpose of this study was to determine whether a fixed-dose formulation of losartan (LOS) plus hydrochlorothiazide (HCTZ) (LOS/HCTZ) is effective in achieving a greater BP lowering in patients with uncontrolled hypertension. METHODS: The study was a prospective, multicenter, observational trial exploring the antihypertensive effect of a single tablet of LOS 50 mg/HCTZ 12.5 mg. A total of 228 patients whose BP had previously been treated with more than one antihypertensive agents without having achieved BP goal below 130/80 mmHg enrolled in the study. RESULTS: A significant decrease in systolic and diastolic BP was observed in both clinic and home measurement after switching from the previous treatment to LOS/HCTZ. There was a significant decrease in both B-type natriuretic peptide (BNP) and urinary albumin creatinine (Cr) excretion ratio (ACR), especially in patients with elevated values. In contrast, there was a significant increase in serum Cr concentration in conjunction with a decrease in estimated glomerular filtration rate (eGFR). Overall serum uric acid (UA) concentration increased, whereas in patients with hyperuricemia there was a significant reduction in this value. CONCLUSION: Switching to LOS/HCTZ provides a greater reduction in clinic and home BP in patients with uncontrolled hypertension. This combination therapy may lead to cardio-, reno protection and improve UA metabolism.

The role of 5-hydroxytryptamine 7 receptors in the phencyclidine-induced novel object recognition deficit in rats.

The role of 5-hydroxytryptamine (serotonin) (5-HT)(7) receptor antagonism in the actions of atypical antipsychotic drugs (APDs), e.g., amisulpride, clozapine, and lurasidone, if any, is uncertain. We examined the ability of 5-HT(7) receptor antagonism alone and as a component of amisulpride and lurasidone to reverse deficits in rat novel object recognition (NOR) produced by subchronic treatment with the N-methyl-D-aspartate receptor antagonist phencyclidine (PCP), and we examined the ability of supplemental 5-HT(7) antagonism to augment the inability of sulpiride, haloperidol, and (1R,4R,5S,6R)-4-amino-2-oxabicyclo[3.1.0]hexane-4,6-dicarboxylic acid (LY379268), a metabotropic glutamate receptor (mGluR) 2/3 agonist, which lack 5-HT(7) antagonism, to reverse the NOR deficit. The 5-HT(7) receptor antagonist, (2R)-1-[(3-hydroxyphenyl)sulfonyl]-2-[2-(4-methyl-1-piperidinyl)ethyl]pyrrolidine (SB269970) (0.1-1 mg/kg) dose-dependently reversed PCP-induced NOR deficits. In addition, the ability of lurasidone (0.1 mg/kg) and amisulpride (3 mg/kg) to reverse this deficit was blocked by cotreatment with the 5-HT(7) receptor agonist (2S)-(+)-5-(1,3,5-trimethylpyrazol-4-yl)-2-(dimethylamino)tetralin (AS19) (5-10 mg/kg), which did not affect NOR in naive rats. Sulpiride, a less potent 5-HT(7) antagonist than amisulpride, did not itself improve the PCP-induced NOR deficit. However, a subeffective dose of SB269970 (0.1 mg/kg) in combination with subeffective doses of lurasidone (0.03 mg/kg), amisulpride (1 mg/kg), or sulpiride (20 mg/kg), also reversed the PCP-induced NOR deficit. Pimavanserin, a 5-HT(2A) inverse agonist, LY379268, and haloperidol did not potentiate the ability of subeffective SB269970 to improve the NOR deficit. Furthermore, the mGluR2/3 antagonist (2S)-2-amino-2-[(1S,2S)-2-carboxycycloprop-1-yl]-3-(xanth-9-yl)propanoic acid (LY341495), which blocks the effect of clozapine to reverse the NOR deficit, did not block the SB269970-induced amelioration of the NOR deficit. These results suggest 5-HT(7) antagonism may contribute to the efficacy of some atypical APDs in the treatment of cognitive impairment in schizophrenia and may itself have some benefit in this regard.

Chronic administration of DSP-7238, a novel, potent, specific and substrate-selective DPP IV inhibitor, improves glycaemic control and beta-cell damage in diabetic mice.

AIMS: The purpose of this study is to assess the in vitro enzyme inhibition profile of DSP-7238, a novel non-cyanopyrrolidine dipeptidyl peptidase (DPP) IV inhibitor and to evaluate the acute and chronic effects of this compound on glucose metabolism in two different mouse models of type 2 diabetes. METHODS: The in vitro enzyme inhibition profile of DSP-7238 was assessed using plasma and recombinant enzymes including DPP IV, DPP II, DPP8, DPP9 and fibroblast activation protein alpha (FAPalpha) with fluorogenic substrates. The inhibition type was evaluated based on the Lineweaver-Burk plot. Substrate selectivity of DSP-7238 and comparator DPP IV inhibitors (vildagliptin, sitagliptin, saxagliptin and linagliptin) was evaluated by mass spectrometry based on the changes in molecular weight of peptide substrates caused by release of N-terminal dipeptides. In the in vivo experiments, high-fat diet-induced obese (DIO) mice were subjected to oral glucose tolerance test (OGTT) following a single oral administration of DSP-7238. To assess the chronic effects of DSP-7238 on glycaemic control and pancreatic beta-cell damage, DSP-7238 was administered for 11 weeks to mice made diabetic by a combination of high-fat diet (HFD) and a low-dose of streptozotocin (STZ). After the dosing period, HbA1c was measured and pancreatic damage was evaluated by biological and histological analyses. RESULTS: DSP-7238 and sitagliptin both competitively inhibited recombinant human DPP IV (rhDPP IV) with K(i) values of 0.60 and 2.1 nM respectively. Neither vildagliptin nor saxagliptin exhibited competitive inhibition of rhDPP IV. DSP-7238 did not inhibit DPP IV-related enzymes including DPP8, DPP9, DPP II and FAPalpha, whereas vildagliptin and saxagliptin showed inhibition of DPP8 and DPP9. Inhibition of glucagon-like peptide-1 (GLP-1) degradation by DSP-7238 was apparently more potent than its inhibition of chemokine (C-X-C motif) ligand 10 (IP-10) or chemokine (C-X-C motif) ligand 12 (SDF-1alpha) degradation. In contrast, vildagliptin and saxagliptin showed similar degree of inhibition of degradation for all the substrates tested. Compared to treatment with the vehicle, single oral administration of DSP-7238 dose-dependently decreased plasma DPP IV activity and improved glucose tolerance in DIO mice. In addition, DSP-7238 significantly decreased HbA1c and ameliorated pancreatic damage following 11 weeks of chronic treatment in HFD/STZ mice. CONCLUSIONS: We have shown in this study that DSP-7238 is a potent DPP IV inhibitor that has high specificity for DPP IV and substrate selectivity against GLP-1. We have also found that chronic treatment with DSP-7238 improves glycaemic control and ameliorates beta-cell damage in a mouse model with impaired insulin sensitivity and secretion. These findings indicate that DSP-7238 may be a new therapeutic agent for the treatment of type 2 diabetes.

Attenuation of phencyclidine-induced object recognition deficits by the combination of atypical antipsychotic drugs and pimavanserin (ACP 103), a 5-hydroxytryptamine(2A) receptor inverse agonist.

Subchronic administration of the N-methyl-d-aspartate receptor antagonist, phencyclidine (PCP), in rodents has been shown to produce impairment in novel object recognition (NOR), a model of visual learning and memory. We tested the hypothesis that the selective 5-HT(2A) inverse agonists, pimavanserin and (R)-(+)-alpha-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenylethyl]-4-piperidinemethanol (M100907), would potentiate subeffective doses of atypical antipsychotic drugs (APDs) to reverse the NOR deficits. Female rats received vehicle or PCP (2 mg/kg b.i.d.) for 7 days, followed by a 7-day washout. Pimavanserin (3 mg/kg) or M100907 (1 mg/kg) alone, or four atypicial APDs, risperidone (0.05-0.1 mg/kg), melperone (1-3 mg/kg), olanzapine (1-2 mg/kg), or N-desmethylclozapine (1-2 mg/kg), and the typical APD, haloperidol (0.05-0.1 mg/kg), were administered alone, or in combination with pimavanserin or M100907, before NOR testing. The exploration times of objects during 3-min acquisition and retention trials, separated by a 1-min interval, were compared by analysis of variance. Vehicle-, but not PCP-treated, animals, explored the novel object significantly more than the familiar in the retention trial (p < 0.05-0.01). Pretreatment with the higher doses of the atypical APDs, but not pimavanserin, M100907, or haloperidol alone, reversed the effects of PCP. The effect of risperidone was blocked by haloperidol pretreatment. Coadministration of pimavanserin or M100907, with ineffective doses of the atypical APDs, but not haloperidol, also reversed the PCP-induced deficit in NOR. These results support the importance of 5-hydroxytryptamine(2A) receptor blockade relative to D(2) receptor blockade in the ability of atypicals to ameliorate the effect of subchronic PCP, a putative measure of cognitive dysfunction in schizophrenia.

Human placental trophoblast cells express alpha-tocopherol transfer protein.

Alpha-tocopherol transfer protein (alpha-TTP), a 30 kDa cytosolic protein first described to be present in the liver and important for alpha-tocopherol trafficking, plays a major role in maintaining alpha-tocopherol levels in plasma, while alpha-tocopherol is known as the major lipid-soluble antioxidant. Expression of alpha-TTP has not only been described in animal model liver, but also in diverse other tissues such as rat brain or pregnant mouse uterus, the latter finding stressing the importance of alpha-TTP for embryogenesis and foetal development. In this study, we report the identification of alpha-TTP in human liver by anti-human alpha-TTP monoclonal antibodies made in rat and the cellular localization of alpha-TTP in term human placenta. By immunohistochemistry, intense staining of alpha-TTP was seen in syncytiotrophoblast as well as in villous and invading extravillous cytotrophoblast, while basal decidual cells showed slighter, but present staining of alpha-TTP. Foetal vessel endothelium remained unstained. It is therefore suggested that alpha-TTP may play a major role in supplying alpha-tocopherol to the foetus prior to delivery and is likely involved in maintaining adequate alpha-tocopherol levels in the foetus.

New visual acuity chart for patients with macular hole.

PURPOSE: To evaluate the usefulness of a new multiple-letter visual acuity chart (MLAC) for the measurement of visual acuity in patients with macular hole. METHODS: Visual acuity was measured using a standard visual acuity chart (Landolt rings, also referred to as C's) and with the MLAC in normal subjects and in patients with a cataract or a macular hole. The MLAC has 14 plates (45 x 45 cm), and on one plate, many Landolt C's were printed with the gaps pointing in the same direction and all of one size. The sizes of the letters and gaps were made to give equivalent visual acuities of 0.1, 0.15, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.5, and 2.0. The spacing between the letters was 33.3% of the diameter of the C's. Each chart projected many C's onto the macular area (5 degrees x 5 degrees ), which permitted the measurement of visual acuity at an extrafoveal point without the patient having to search for the extrafoveal point with the best acuity. RESULTS: There was no difference in the acuity measurement determined with the standard chart and the MLAC in normal subjects and patients with cataracts. Twelve of 16 patients with open macular hole, however, demonstrated higher acuity measurement (more than two lines) on the MLAC than on the standard chart. The improvement of visual acuity measurement after successful macular hole surgery was significantly less with the MLAC than with the standard chart. CONCLUSIONS: Our results suggest that the standard acuity chart, when administered before surgery, underestimates the patient's potential visual acuity after surgery, whereas the MLAC provides a better estimate of the patient's postoperative acuity. The MLAC can be a useful tool for measuring visual acuity in patients with macular hole.

Association of angiotensinogen gene polymorphism with erythropoietin-induced hypertension: a preliminary report.

The association of the angiotensinogen (AGT) gene variation at codon 235, the T235 variant, with hypertension induced by erythropoietin (Epo) was investigated in patients with progressive renal disease requiring treatment for renal anemia with Epo. The subjects for the study were patients with renal diseases with serum creatinine concentration exceeding 2 mg/dl and a hematocrit (Ht) of less than 30%. During the run-in period, blood pressure was well controlled with an appropriate salt restricted diet and/or antihypertensive treatment. The patients were then given 6,000 IU of Epo once a week until the Ht rose by 5%. For the overall patient group, AGT gene polymorphism analysis revealed T235T (T/T) in 31 cases (61%), M235T (M/T) in 19 cases (37%), and M235M (M/M) in 1 case (2%). In response to treatment with Epo, hypertension (defined as an increase in mean blood pressure greater than 10 mmHg) was found in 11 cases (22%), all of who carried the homozygous T allele (T/T). On the other hand, the frequency of T/T in patients who did not develop hypertension was 50% (T/T:T/M=20:19 cases), indicating a significant difference (p=0.003 by Chi-square). Variables estimated to be associated with Epo-induced hypertension were the T allele, gender (male), and the degree of increase in Ht, in descending order. Our preliminary research indicates that individuals who carry two copies of the T allele, i.e., who are homozygous for T, are highly susceptible to development of hypertension when subjected to Epo. These results suggest that the AGT T235 variant may be the primary gene responsible for the development of Epo-induced hypertension.

A contact lens electrode with built-in high intensity white light-emitting diodes. A contact lens electrode with built-in white LEDs.

We determined the clinical usefulness of a new contact lens electrode with built-in, white light-emitting diodes (LEDs) for full-field electroretinograms (ERGs). Three, high-brightness white LEDs were incorporated into a contact lens electrode and served as the source for the stimulus and the background. The stimulus intensity, stimulus duration and background illumination were regulated by a small LED control device. Maximum stimulus and background intensities were 3.9 and 3.6 log cd/m2, respectively. We successfully recorded intensity-response series for scotopic and photopic ERGs. We also recorded a duration-series for photopic ERGs, and ERGs that were comparable to the ISCEV standardized ERGs. The compactness and ease of using this system suggest that it will be clinically useful under different conditions.

Na(+) action potentials in human photoreceptors.

Mammalian photoreceptors are hyperpolarized by a light stimulus and are commonly thought to be nonspiking neurons. We used the whole-cell patch-clamp technique on surgically excised human retina to examine whether human photoreceptors can elicit action potentials. We discovered that human rod photoreceptors express voltage-gated Na(+) channels, and generate Na(+) action potentials, in response to membrane depolarization from membrane potentials of -60 or -70 mV. Na(+) spikes in human rods were elicited at the termination of a light response that hyperpolarized the potential well below -50 mV. This served to amplify the release of a neurotransmitter when a bright light is turned off, and thus selectively amplify the off response to the light signal.

Multifocal ERG findings in complete type congenital stationary night blindness.

PURPOSE: To study the multifocal electroretinogram (mfERG) in patients with the complete type of congenital stationary night blindness (cCSNB), which is thought to be due to a defect in neurotransmission from the photoreceptors to the ON-bipolar cells. METHODS: mfERGs were recorded with the VERIS recording system from four patients with cCSNB, none of whom had nystagmus. The stimulus array consisted of 61 hexagons, and the total recording time was approximately 4 minutes. The amplitudes and implicit times of the first- and second-order kernels of the local responses were compared with those from 20 myopic controls. Waveforms of the summed response from all locations were also compared between the two groups. RESULTS: The first-order kernels of the mfERGs of cCSNB patients had normal amplitudes but delayed implicit times for nearly the whole field tested. The second-order kernel was severely attenuated in amplitude in cCSNB patients. The ratios of the second- to first-order kernel amplitudes were significantly reduced in cCSNB and clearly separated the cCSNB group from the control group without any overlap of the values. CONCLUSIONS: The second-order kernel, which is involved in adaptative mechanism of the retina to repeated flashes, is selectively reduced in cCSNB. The delay of the implicit times of the first-order kernel in patients with cCSNB may be related to the severe amplitude reduction of the second-order kernel.

Molecular nature of ultraviolet B light-induced deletions in the murine epidermis.

Depletion of the stratospheric ozone layer leads to an increase in ambient UV loads, which are expected to raise skin cancer incidences. Tumor development in the skin could be a multistep process in which various genetic alterations, such as point mutations and deletions, occur successively. Here, we demonstrate that UVB irradiation efficiently induces deletions in the epidermis using a novel transgenic mouse, gpt delta. In this mouse model, deletions in lambda DNA integrated in the chromosome are preferentially selected as Spi(-) (sensitive to P2 interference) phages, which can then be subjected to molecular analysis. The mice were exposed to UVB at single doses of 0.3, 0.5, 1.0, 1.5, and 2.0 kJ/m(2). After 4 weeks, lambda phage was rescued from the genomic DNA of the epidermis by in vitro packaging reactions. The mutant frequencies of Spi(-) with large deletions in the epidermis increased >15-fold at a UVB dose of 0.5 kJ/m(2) over the control. Molecular sizes of most of the large deletions were >1000 bp. More than one-half of the large deletions occurred between short direct-repeat sequences from 1 to 6 bp, and the remainder had flush ends. In the unirradiated mouse, almost all of the Spi(-) mutants were 1-bp frameshifts in runs of identical bases. These results suggest that UVB irradiation induces deletions in the murine epidermis, and most of the deletions are generated through end-joining of double strand breaks in DNA.

The vascular anatomy of the developing zebrafish: an atlas of embryonic and early larval development.

We have used confocal microangiography to examine and describe the vascular anatomy of the developing zebrafish, Danio rerio. This method and the profound optical clarity of zebrafish embryos make it possible to view the entire developing vasculature with unprecedented resolution. A staged series of three-dimensional images of the vascular system were collected beginning shortly after the onset of circulation at 1 day postfertilization through early- to midlarval stages at approximately 7 days postfertilization. Blood vessels in every region of the animal were imaged at each stage, and detailed "wiring patterns" were derived describing the interconnections between every major vessel. We present an overview of these data here in this paper and in an accompanying Web site "The interactive atlas of zebrafish vascular anatomy" online at (http://eclipse.nichd.nih.gov/nichd/lmg/redirect.html). We find a highly dynamic but also highly stereotypic pattern of vascular connections, with different sets of primitive embryonic vessels severing connections and rewiring in new configurations according to a reproducible plan. We also find that despite variation in the details of the vascular anatomy, the basic vascular plan of the developing zebrafish shows strong similarity to that of other vertebrates. This atlas will provide an invaluable foundation for future genetic and experimental studies of vascular development in the zebrafish.

Hypoplasia of the left lobe of the liver.

In a forensic autopsy, hypoplasia of the left lobe (lateral segment) of the liver was found. Although the cause was unknown, the morphologic anomaly observed in this case was regarded as congenital because there was no history of surgery. Moreover, the main vessels of the left lobe were present despite complete absence of the parenchyma.

Characterization of mutations induced by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine in the colon of gpt delta transgenic mouse: novel G:C deletions beside runs of identical bases.

Mutations induced by one of the typical dietary mutagens/carcinogens, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), were characterized using gpt delta transgenic mice. This transgenic mouse model has two selection methods to efficiently detect different types of mutations, i.e. 6-thioguanine selection for point mutations and Spi(-) selection for deletions. The mice were fed with a diet containing 400 p.p.m. PhIP for 13 weeks and gpt and Spi(-) mutations were analyzed from the colon, where the highest mutant frequencies were detected. Concerning the types of gpt mutations from PhIP-treated mice, 81% were single base pair substitutions and G:C-->T:A transversions predominated; single base pair deletions at G:C base pairs were also observed. In untreated mice G:C-->A:T transitions predominated and >80% of these events involved 5'-CpG-3' sites. Concerning Spi(-) mutants from PhIP-treated mice, 76% were G:C base pair deletions and more than half of these events occurred in monotonic G or C run sequences. Interestingly, a novel type of frameshift motif, i.e. G:C base pair deletions beside run sequences, was observed. The most frequently observed mutation in this class was the 5'-TTTTTTG-3'-->5'-TTTTTT-3' event. These results suggest that PhIP induces point mutations, such as base substitutions and single base pair deletions, rather than larger deletions in vivo and that run sequences may play an important role in PhIP-induced G:C base pair deletions.