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91.
Primary heart neoplasms are rare occurring with an estimated incidence of 0.0017-0.19%. Myxoma is the most prevalent primary heart tumor. The right atrium is an unusual localization, occurring only in 15-20% of myxoma cases. We report a rare case of a massive right atrial myxoma causing tricuspid valve obstruction and presenting as syncope and exertional dyspnea. This case illustrates the influence of myxoma's size, position and mobility as well as patient's body posture and respiration to the development of signs and symptoms. Three-dimensional echocardiography proved useful in surgery planning, allowing a better definition of the tumor outline and attachment.  相似文献   
92.
93.
Five bombesin analogs with different functional groups at the C-terminus were synthesized using a solid-phase strategy. The protocols were optimized using 4-(hydroxymethyl)benzoic acid (HMBA) resin to synthesize a common precursor followed by nucleophilic cleavage of the base sensitive peptide ester linkage. The C-terminal modifications included ethylamide, butylamide, methyl ester, propyl ester and hydrazide. Cleavage from the resin was possible with the fully protected or deprotected precursor peptide; however, higher purity of the final products was achieved when cleavage protocols were conducted after side-chain deprotection. The synthesized peptides were analyzed and characterized using reverse phase HPLC and ESI-MS. The peptides were obtained in 13-32% overall recovery, calculated from the coupling efficiency of the first amino acid residue, and in 91-97% purity.  相似文献   
94.
Ischemic heart disease is considered to be one of the leading causes of death in adults. While extensive research on mechanisms contributing to the pathogenesis of myocardial infarction (MI) has been underway, it is not known whether insulin receptor characteristics and postreceptor signaling have been fully addressed as yet. Present work attempts to investigate whether the remodeling process effectively induces alteration(s) in insulin-binding characteristics at the coronary endothelium and cardiomyocytes using a rat heart model of MI. MI was induced by ligation of the left anterior descending coronary artery of adult male Sprague-Dawley rats. Two animal groups were used in the study: (i) sham-operated CHAPS-untreated and CHAPS-treated, and (ii) MI CHAPS-untreated and MI CHAPS-treated. A physical model describing 1:1 stoichiometry of reversible insulin binding to its receptors present on the endothelium and at cardiomyocytes after CHAPS treatment was considered for data analysis. Quantitation of the collected effluents after heart perfusion, the inlet at the aortic and outlet at the coronary sinus sites, were curve fitted using a first-order Bessel function, which determines the binding constants (k(n)), the reversible constant (k(-n)), the dissociation constant (k(d) = k(-n)/k(n)), and the residency time constant (tau = 1/k(-n)). In addition, hearts were excised, separated into right and left ventricles, and individually weighed, and areas of infarcted regions were measured. Results of the MI group showed significant increases in relative heart mass, left ventricle mass, and right ventricle mass normalized to total body mass. MI induced severe ischemia and irreversible myocardial injury as assessed by planimetry and histologic studies. The data showed differences in insulin receptor affinities at the endothelial and cardiac myocytes in the sham and in the MI-operated rats. The observed reduction in the binding affinity of insulin at the myocyte postinfarction may explain the pathogenic role of insulin in ischemic heart disease and, hence, resistance. Therefore, insulin administration during and post MI might be cardioprotective.  相似文献   
95.
Most estrous cycles in cows consist of 2 or 3 waves of follicular activity. Waves of ovarian follicular development comprise the growth of dominant follicles some of which become ovulatory and the others are anovulatory. Ovarian follicular activity in cows during estrous cycle was studied with a special reference to follicular waves and the circulating concentrations of estradiol and progesterone. Transrectal ultrasound examination was carried out during 14 interovulatory intervals in 7 cows. Ovarian follicular activity was recorded together with assessment of serum estradiol and progesterone concentrations. Three-wave versus two-wave interovulatory intervals was observed in 71.4% of cows. The 3-wave interovulatory intervals differed from 2-wave intervals in: 1) earlier emergence of the dominant follicles, 2) longer in length, and 3) shorter interval from emergence to ovulation. There was a progressive increase in follicular size and estradiol production during growth phase of each wave. A drop in estradiol concentration was observed during the static phase of dominant anovulatory follicles. The size of the ovulatory follicle was always greater and produced higher estradiol compared with the anovulatory follicle. In conclusion, there was a predominance of 3-wave follicular activity that was associated with an increase in length of interovulatory intervals. A dominant anovulatory follicle during its static phase may initiate the emergence of a subsequent wave. Follicular size and estradiol concentration may have an important role in controlling follicular development and in determining whether an estrous cycle will have 2 or 3-waves.  相似文献   
96.
Epidemiological studies have shown an inverse association between dietary intake of lycopene and prostate cancer risk. We conducted a clinical trial to investigate the biological and clinical effects of lycopene supplementation in patients with localized prostate cancer. Twenty-six men with newly diagnosed prostate cancer were randomly assigned to receive a tomato oleoresin extract containing 30 mg of lycopene (n = 15) or no supplementation (n = 11) for 3 weeks before radical prostatectomy. Biomarkers of cell proliferation and apoptosis were assessed by Western blot analysis in benign and cancerous prostate tissues. Oxidative stress was assessed by measuring the peripheral blood lymphocyte DNA oxidation product 5-hydroxymethyl-deoxyuridine (5-OH-mdU). Usual dietary intake of nutrients was assessed by a food frequency questionnaire at baseline. Prostatectomy specimens were evaluated for pathologic stage, Gleason score, volume of cancer, and extent of high-grade prostatic intraepithelial neoplasia. Plasma levels of lycopene, insulin-like growth factor-1, insulin-like growth factor binding protein-3, and prostate-specific antigen were measured at baseline and after 3 weeks of supplementation or observation. After intervention, subjects in the intervention group had smaller tumors (80% vs 45%, less than 4 ml), less involvement of surgical margins and/or extra-prostatic tissues with cancer (73% vs 18%, organ-confined disease), and less diffuse involvement of the prostate by high-grade prostatic intraepithelial neoplasia (33% vs 0%, focal involvement) compared with subjects in the control group. Mean plasma prostate-specific antigen levels were lower in the intervention group compared with the control group. This pilot study suggests that lycopene may have beneficial effects in prostate cancer. Larger clinical trials are warranted to investigate the potential preventive and/or therapeutic role of lycopene in prostate cancer.  相似文献   
97.
Aerobic metabolism of phenylalanine in most bacteria proceeds via oxidation to phenylacetate. Surprisingly, the further metabolism of phenylacetate has not been elucidated, even in well studied bacteria such as Escherichia coli. The only committed step is the conversion of phenylacetate into phenylacetyl-CoA. The paa operon of E. coli encodes 14 polypeptides involved in the catabolism of phenylacetate. We have found that E. coli K12 mutants with a deletion of the paaF, paaG, paaH, paaJ or paaZ gene are unable to grow with phenylacetate as carbon source. Incubation of a paaG mutant with [U-13C8]phenylacetate yielded ring-1,2-dihydroxy-1,2-dihydrophenylacetyl lactone as shown by NMR spectroscopy. Incubation of the paaF and paaH mutants with phenylacetate yielded delta3-dehydroadipate and 3-hydroxyadipate, respectively. The origin of the carbon atoms of these C6 compounds from the aromatic ring was shown using [ring-13C6]phenylacetate. The paaG and paaZ mutants also converted phenylacetate into ortho-hydroxyphenylacetate, which was previously identified as a dead end product of phenylacetate catabolism. These data, in conjunction with protein sequence data, suggest a novel catabolic pathway via CoA thioesters. According to this, phenylacetyl-CoA is attacked by a ring-oxygenase/reductase (PaaABCDE proteins), generating a hydroxylated and reduced derivative of phenylacetyl-CoA, which is not re-oxidized to a dihydroxylated aromatic intermediate, as in other known aromatic pathways. Rather, it is proposed that this nonaromatic intermediate CoA ester is further metabolized in a complex reaction sequence comprising enoyl-CoA isomerization/hydration, nonoxygenolytic ring opening, and dehydrogenation catalyzed by the PaaG and PaaZ proteins. The subsequent beta-oxidation-type degradation of the resulting CoA dicarboxylate via beta-ketoadipyl-CoA to succinyl-CoA and acetyl-CoA appears to be catalyzed by the PaaJ, PaaF and PaaH proteins.  相似文献   
98.
Appropriate knowledge of the parental cultivars is a pre-requisite for a successful breeding program. This study characterized fruit yield, quality attributes, and molecular variations of ten tomato cultivars during three consecutive generations under greenhouse conditions. Peto 86, Castle Rock, and Red Star cultivars showed the highest fruit yield (kg/plant), total phenolic compounds (TPC), and sap acidity. Principal component analysis categorized the evaluated fruit yield into three groups based on their quality attributes. A robust positive correlation appeared among traits inside each group. A positive correlation was likewise noticed between the first and the second groups. However, a negative correlation was detected between the first, the second and the third group. Molecular profiling, using seven inter-simple sequence repeat (ISSR) primers, produced 60 loci, including 49 polymorphic loci. The molecular analysis also pinpointed the highest genetic similarity (0.92) between P73 and Moneymaker, while the lowest genetic similarity (0.46) was observed between Castle Rock and Moneymaker. The cultivars P73 and Moneymaker showed the lowest genetic distance (2.24), while the highest genetic distance (5.92) was observed between Super Marmand and Peto86, on the one hand, and between Castle Rock and Moneymaker, on the other hand. The chemical analysis of fruit sap indicated the highest levels of TPC, total flavonoids, anthocyanin, ascorbic acid and total soluble solids in Peto 86 and Castle Rock cultivars. Phylogeny analysis of tomato cultivars based on morphological and molecular attributes indicated four distinct clades. Peto 86, Castle Rock, and Red star cultivars can be recommended for the tomato hybridization breeding programs in the future, with other tomato cultivars as potentially high-yielding parents.  相似文献   
99.
The self-association of several N-urethanyl-L-amino acids (N-t-Boc-glycine, N-t-Boc-L-alanine, N-t-Boc-L-methionine, and N-t-Boc-O-Bz-L-tyrosine has been investigated in carbon tetrachloride by Fourier transform (FTIR) spectrometry. The fractions of nonbonded OH and NH groups have been determined from the intensities of the free OH and NH-stretching vibrations. The FTIR spectra have been examined in the carbonyl stretching regions by using Fourier self-deconvolution techniques. The results show that intermolecular hydrogen bonds are formed between the carboxylic acid group of one molecule and the urethane group of another molecule, suggesting that the leading factor for the self-association of N-t-Boc amino acids is the acidity of the OH groups. In N-t-Boc glycine, more heterodimers are formed than in the other amino acids. In N-t-Boc-O-Bz-L-tyrosine where the steric hindrance of the substituent implanted on the Cα atom is higher, the concentration of homodimers and heterodimers is lower than in N-t-Boc-L-alanine or N-t-Boc-L methionine. © 1997 John Wiley & Sons, Inc.  相似文献   
100.
Gastric cancer (GC) is frequently characterized by resistance to standard chemotherapeutic regimens and poor clinical outcomes. We aimed to identify a novel therapeutic approach using drug sensitivity testing (DST) and our computational SynerySeq pipeline. DST of GC cell lines was performed with a library of 215 Federal Drug Administration (FDA) approved compounds and identified clofarabine as a potential therapeutic agent. RNA-sequencing (RNAseq) of clofarabine treated GC cells was analyzed according to our SynergySeq pipeline and identified pictilisib as a potential synergistic agent. Clonogenic survival and Annexin V assays demonstrated increased cell death with clofarabine and pictilisib combination treatment (P<0.01). The combination induced double strand breaks (DSB) as indicated by phosphorylated H2A histone family member X (γH2AX) immunofluorescence and western blot analysis (P<0.01). Pictilisib treatment inhibited the protein kinase B (AKT) cell survival pathway and promoted a pro-apoptotic phenotype as evidenced by quantitative real time polymerase chain reaction (qRT-PCR) analysis of the B-cell lymphoma 2 (BCL2) protein family members (P<0.01). Patient derived xenograft (PDX) data confirmed that the combination is more effective in abrogating tumor growth with prolonged survival than single-agent treatment (P<0.01). The novel combination of clofarabine and pictilisib in GC promotes DNA damage and inhibits key cell survival pathways to induce cell death beyond single-agent treatment.  相似文献   
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