Simultaneous assessment of coronary flow reserve and left ventricular function during vasodilator stress evaluated by 13N-ammonia hybrid PET/MRI.

AIM: To explore changes in left ventricular (LV) function and the relationship of these changes with myocardial blood flow (MBF) evaluated by 13N-ammonia hybrid positron-emission tomography (PET)/magnetic resonance imaging (MRI) during vasodilator stress in patients with suspected coronary artery disease (CAD). MATERIALS AND METHODS: Fifty-two consecutive patients with suspected CAD, who underwent 13N-ammonia PET/MRI, were enrolled. Vasodilator stress was induced by intravenous injection of adenosine. MBF and coronary flow reserve (CFR) were calculated from dynamic acquisition of 13N-ammonia PET. LV function was evaluated by MRI both at rest and during vasodilator stress. An abnormal perfusion on myocardial images was defined as a summed difference score of ≥4. RESULTS: MRI showed that the LV end-diastolic volume, LV end-systolic volume, and LV ejection fraction (LVEF) remained unchanged during vasodilator stress in all patients (n=52) as well as in the patients with CFR of <2 (n=27), stress MBF of <1.3 ml/g/min (n=28), abnormal myocardial perfusion (n=30), and more than one diseased vessel (n=46). In only four patients, the LVEF measured by MRI decreased by >5% during vasodilator stress. In these four patients, CFR was lower (1.57 ± 0.12 versus 2.18 ± 0.86, p<0.01) and the number of diseased vessels was higher (2.75 ± 0.50 versus 1.48 ± 0.92, p<0.01) than in patients without post-stress LV dysfunction. CONCLUSION: The LV volume and systolic function evaluated by cardiac MRI remained unchanged during vasodilator stress; however, LV dysfunction during vasodilator stress may occur in patients with severe CAD.

Accumulation of SNAP25 in mouse gustatory and somatosensory cortices in response to food and chemical stimulation.

Food intake stimuli, including taste, somatosensory, and tactile stimuli, are received by receptors in the oral cavity, and this information is then transferred to the cerebral cortex. Signals from recently ingested food during the weaning period can affect synaptic transmission, resulting in biochemical changes in the cerebral cortex that modify gustatory and somatosensory nervous system plasticity. In this study, we investigated the expression patterns of molecular markers in mouse gustatory and somatosensory cortices during the weaning period. The expression of synaptosomal-associated protein 25 (SNAP25), a component of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex, was increased in the insular and somatosensory cortices at postnatal week 3 compared to postnatal week 2. Additionally, SNAP25 protein in the cerebral cortex accumulated in weaning mice fed solid food but not in mice fed only mother's milk at the weaning stage. Chemical stimulation by saccharin or capsaicin at the weaning stage also increased SNAP25 immunoreactivity in the insular or somatosensory cortical area, respectively. These results suggest that recently ingested chemical signals in the oral cavity during weaning increase the accumulation of SNAP25 in the gustatory and somatosensory cortices and promote neural plasticity during the development of the gustatory and somatosensory nervous systems.

Utilization of oryzacystatin for regulating the ripening of squid shiokara, a traditional Japanese salted and fermented seafood.

Shiokara is a fermented seafood composed of sliced squid mantle muscle ripened with fresh squid liver. Preliminary sensory evaluation by using the ranking test revealed that the hardness of squid muscle in shiokara was reduced within 7 d of ripening. During the process of ripening, muscle proteins were digested by proteinases present in squid liver. The degradation of paramyosin and myosin heavy chain was observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The hardness of squid mantle muscle in shiokara was reduced with the degradation of paramyosin and myosin heavy chain. This degradation was mainly caused by E-64-sensitive cysteine proteinases. To control the hardness of shiokara, we used rice seed oryzacystatin, which suppresses proteolysis by papain-like cysteine proteinases. When oryzacystatin was added 4 d after the start of shiokara ripening, the muscle protein degradation stopped, without further muscle softening. These results show that oryzacystatin is useful to control the ripening of shiokara by regulating its hardness.

Construction of a taste-blind medaka fish and quantitative assay of its preference-aversion behavior.

In vertebrates, the taste system provides information used in the regulation of food ingestion. In mammals, each cell group within the taste buds expresses either the T1R or the T2R taste receptor for preference-aversion discrimination. However, no such information is available regarding fish. We developed a novel system for quantitatively assaying taste preference-aversion in medaka fish. In this study, we prepared fluorescently labeled foods with fine cavities designed to retain tastants until they were bitten by the fish. The subjects were fed food containing a mixture of amino acids and inosine monophosphate (AN food), denatonium benzoate (DN food) or no tastant (NT food), and the amounts of ingested food were measured by fluorescence microscopy. Statistical analysis of the fluorescence intensities yielded quantitative measurements of AN food preference and DN food aversion. We then generated a transgenic fish expressing dominant-negative Galpha(i2) both in T1R-expressing and in T2R-expressing cells. The feeding assay revealed that the transgenic fish was unable to show a preference for AN food and an aversion to DN food. The assay system was useful for evaluating taste-blind behaviors, and the results indicate that the two taste signaling pathways conveying preferable and aversive taste information are conserved in fish as well as in mammals.

Crossover trial for lipid abnormality in postmenopausal breast cancer patients during selective estrogen receptor modulators (SERMs) administrations.

The objective of this study was to evaluate the different profiles of serum lipids resulting from the administration of selective estrogen receptor modulators (SERMs). Postmenopausal primary breast cancer patients (n = 197) with node-negative, hormone receptor-positive who were treated at our department or in other related medical institutions from April 1997 through March 2001 were given adjuvant therapy. The adjuvant therapy included 1 year's administration of tamoxifen (TAM) 20 mg or toremifene (TOR) 40 mg. The profiles of serum lipids such as total cholesterol (TC), high-density lipoprotein cholesterol (HDL) and triglyceride (TG) were observed. After 1 year administration TC had significantly decreased (p < 0.001) both in the TAM group and the TOR group, but no significant difference was found between these groups (p = 0.249). HDL had significantly decreased in the TAM group (p < 0.001), while it had significantly increased in the TOR group (p < 0.001), and a significant difference was found between the groups (p < 0.001). TG had significantly increased in the TAM group (p < 0.001) but significantly decreased in the TOR group (p < 0.001). The medication was switched in those who still had abnormal lipid metabolism and given to them for another year. After 1 year from the crossover TC and HDL had increased to the levels of before administration (p < 0.001) and TG had decreased in those (n = 57) whose medication was switched from TAM to TOR. While TC had decreased and TG had increased in those (n = 23) whose medication was switched from TOR to TAM (p < 0.001). The above findings have suggested that TOR provides better profiles of lipid metabolism than TAM.

Mammary ductoscopy for diagnosis and treatment of intraductal lesions of the breast.

BACKGROUND: Mammary ductoscopy (mammoscopy) is an ideal diagnostic method for intraductal lesions. The usefulness of mammoscopy for intraductal lesions was evaluated. METHODS: Mammoscopy was performed in 315 cases with nipple discharge. The mammoscopic findings of 46 breast cancer cases (47 lesions) and 109 intraductal papilloma cases (119 lesions) were compared with pathological findings. RESULTS: Carcinoma was recognized by mammoscopy in 38 of 47 lesions (80.9%). Intraductal masses were detected by mammoscopy in 115 of 119 intraductal papilloma lesions. The shape of the mass was classified as hemispheric, papillary, or flat protrusion. The hemispheric and papillary shapes were most common in cases of intraductal papilloma and the flat protrusion type was most common in cases of carcinoma. The amount of material collected by intraductal biopsy under mammoscopic observation was smaller in carcinoma than in intraductal papilloma because the carcinoma lesions were usually located in peripheral duct-lobular units and had weak tissue cohesion compared with that of intraductal papilloma. Of 133 intraductal biopsies performed for 69 intraductal papillomas, 17 biopsies yielded material insufficient for diagnosis in. The effectiveness of treatment by intraductal biopsy was recognized in 38 of 46 intraductal papillomas in which clinical follow-up continued for more than two years (82.6%). The therapeutic results of biopsy were poor in cases of multiple intraductal masses in multiple duct-lobular units. CONCLUSIONS: Mammoscopy contributes not only the diagnosis in cases of nipple discharge, but is also of benefit in the treatment of intraductal papilloma.

Molecular cloning, characterization, and expression of wheat cystatins.

We cloned four kinds of cDNAs of wheat cystatins (WCs), WC1, WC2, WC3, and WC4, from the seed. They had 47-68% amino acid sequence similarities to other plant cystatins. WC1, WC2, and WC4 had 63-67% similalities to one another while 93% of amino acids were identical between WC1 and WC3. This suggested that WCI, WC2, and WC4 should be regarded as the isoforms of wheat cystatins. The mRNAs for WC1, WC2, and WC4 were all expressed in seed at an early stage of maturation and, after that, their quantities decreased gradually. However, each of the mRNAs was again expressed one day after the start of germination and the expression continued for the following five days. WC1 seemed to be expressed at a higher level than WC2 and WC4. Immunostaining for looking at site-specific expression of each WC demonstrated that both WC1 and WC4 existed in the aleuron layer and embryo, but in the endosperm the only existing species was WC1. Differences in mRNA level and tissue localization found for the WCs may suggest their differential physiological roles.

[Significance of thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) activity in breast cancer tissue].

TS, DPD, uridine phosphorylase and thymidine phosphorylase are enzymes involved in the metabolism of the anticancer drug pyrimidine fluoride. In this study, levels of these enzymes were measured in 47 women with primary breast cancer. These enzyme levels were then compared to levels determined from breast cancer patients who received either preoperative chemotherapy or nothing, in order to determine whether they might predict clinical outcome. The TS inhibition rate was significantly higher (p < 0.05) in patients receiving preoperative chemotherapy (20.4 +/- 13.3%) than in the untreated group (11.4 +/- 9.8%). No other significant differences in activity were noted between the treated and untreated groups for any of the other enzymes studied. The activity of each enzyme at the tumor site and the tumor/normal (T/N) ratio were also compared between patients with and without recurrence. The TS inhibition rate at the tumor site was lower in recurring cases than in non-recurring cases, and the T/N ratio tended to be higher for DPD in patients with recurrences. These findings indicate that the TS inhibition rate and DPD activity may be useful predictors for early recurrence of breast cancer following surgery.

A gustatory cyclic nucleotide-gated channels CNGgust, is expressed in the retina.

Cyclic nucleotide-gated (CNG) channels are essential proteins that contribute to the intracellular signal transduction of the senses of sight and smell. Recently, we found a novel CNG channel (CNGgust) in rat taste buds, and demonstrated its possible involvement in taste signal transduction. In the present study, we used RT-PCR and immunostaining to prove that this gustatory CNG channel is expressed in the outer segments of rat cone photoreceptor cells. The study strongly suggests that the senses of taste and sight share, at least in part, a common signal transduction pathway.

Molecular cloning and taste bud-specific expression of a novel cyclic nucleotide-gated channel.

Cyclic nucleotide-gated (CNG) channels serve as downstream targets of signaling pathways in vertebrate photoreceptor cells and olfactory sensory neurons. For taste signaling as well, a great deal of information is available predicting the presence of a CNG channel, but no report has been presented on its molecular entity. Here we report on molecular cloning and functional expression of a taste bud-specific CNG channel tentatively named CNGgust. Reverse transcriptase polymerase chain reaction (RT-PCR) primers were synthesized according to some amino acid sequences generally conserved in many CNG channels. RT-PCR was conducted using rat circumvallate papillary mRNA-derived cDNA as a template to obtain positive clones. A corresponding genomic DNA clone was then obtained by screening from a genomic DNA library. Dissecting the entire structure of this gene, we found that the encoding protein had an amino acid sequence similarity of 80% to each of retina and olfactory CNG channels. It was also found by immunostaining with a specific antibody that this gustatory CNG channel (CNGgust) is localized in the tongue and also expressed specifically on the pore side of each taste bud in the circumvallate papillae. Electrophysiological experiments demonstrated that CNGgust resided in a functional state. All these data suggest that CNGgust may be involved in taste signal transduction in sensory cells.

Taste buds have a cyclic nucleotide-activated channel, CNGgust.

Cyclic nucleotide-gated (CNG) channels have been characterized as important factors involved in physiological processes including sensory reception for vision and olfaction. The possibility thus exists that a certain CNG channel functions in gustation as well. In the present study, we carried out reverse transcription-polymerase chain reaction and genomic DNA cloning and characterized a CNG channel (CNGgust) as a cyclic nucleotide-activated species expressed in rat tongue epithelial tissues where taste reception takes place. Several types of 5'-rapid amplification of cDNA ends clones of CNGgust cDNA were obtained with various 5'-terminal sequences. As the CNGgust gene was a single copy, the formation of such CNGgust variants should result from alternative splicing. The encoded protein was homologous to known vertebrate CNG channels with 50-80% similarities in amino acid sequence, and particularly homologous to bovine testis CNG channel and human cone CNG channel with 82% similarities. CNGgust was functional when expressed in human embryonic kidney cells, where it opened upon the addition of cGMP or cAMP. Immunohistochemical analysis using an antibody raised against a CNGgust peptide demonstrated the channel to be localized on the pore side of each taste bud in the circumvallate papillae, with no signal observed for degenerated taste buds after denervation of the glossopharyngeal nerve. All these results, together with the indication that cyclic nucleotides play a role gustatory signaling pathway(s), strongly suggest the involvement of CNGgust in taste signal transduction.

Soyacystatin, a novel cysteine proteinase inhibitor in soybean, is distinct in protein structure and gene organization from other cystatins of animal and plant origin.

Cystatins, cysteine proteinase inhibitors, deserve note because of their regulatory and protective functions in plant tissues. We isolated both genomic DNA and cDNA clones from soybean that encode a cystatin consisting of 245 amino acid residues (soyacystatin). It is, while basically similar in sequence to known cystatins that are generally in the range of 12-15 kDa, characterized by having extremely large extension sequences in both its amino and carboxyl termini. The genomic DNA encoding soyacystatin is also unique in that it consists of four exons with three introns in its coding regions. The mRNA for soyacystatin is distinctly expressed in soybean seeds 2 weeks after flowering. Soyacystatin purified from mature soybean seeds had a molecular mass of about 26 kDa on SDS/PAGE which suggests that it contains the extension sequences. Papain-inhibition experiments demonstrate that this endogenous soyacystatin has almost the same inhibitory activity as that of its deletion mutant (102 amino acid residues) recombinantly produced by truncation of the amino and carboxyl terminal extensions, indicating that the occurrence of the extensions does not affect the cystatin activity. Immunohistochemical experiments reveal that soyacystatin is expressed nearly uniformly in the cotyledons. These results also suggest the possible occurrence of a cysteine proteinase as the target enzyme of soyacystatin.

A water channel closely related to rat brain aquaporin 4 is expressed in acid- and pepsinogen-secretory cells of human stomach.

We isolated a cDNA clone encoding a water channel protein, aquaporin ( AQP), from human stomach. The encoded protein consisted of 323 amino acid residues, containing six putative transmembrane domains. The protein was designated human aquaporin 4 (hAQP4) because of its 94% sequence similarity to rat brain AQP4. Expression of hAQP4 cRNA in Xenopus oocytes resulted in a significant increase in osmotic water permeability, indicating that this protein functions as a water channel. Northern blot analysis demonstrated a strong signal of hAQP4 mRNA in brain, lung, and skeletal muscle as well as in stomach. Immunohistochemical experiments with human stomach tissues showed that hAQP4 as a protein is expressed mainly in cells located in the glandular portion of the fundic mucosa. These include chief cells which secrete pepsinogen and parietal cells which secrete hydrochloric acid. These results strongly indicate that hAQP4 is a principal factor involved in the osmotic regulation of pepsinogen and acid secretion in the stomach.