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S S Sun

Publications and source records attributed to S S Sun.

At least 73 records · Page 4Linked to original sources
PubMed1992

Structure and expression of a sugarcane gene encoding a housekeeping phosphoenolpyruvate carboxylase.

A gene (SCPEPCD1) encoding phosphoenolpyruvate carboxylase (PEPC) was isolated from the C-4 monocot sugarcane (Saccharum hybrid var. H32-8560). SCPEPCD1 is ca. 6800 bp long, with 10 exons. The entire gene sequence from -1561 to 262 bp downstream of the putative poly(A) addition signal is reported. A low-level, essentially constitutive pattern of expression, amino acid sequence similarities to other 'housekeeping' PEPC enzymes, and the absence of DNA sequence elements conserved in the upstream region of maize and sorghum C-4-specific PEPC genes indicate that SCPEPCD1 encodes a housekeeping PEPC. Despite this, a motif proposed to act as a phosphorylation site in light-mediated activation of photosynthetic PEPC enzymes [10] is present in the SCPEPCD1 protein; evidence is presented for the presence of this site in other housekeeping PEPC proteins.

Amino Acid Sequence↗
PubMed1992

Comparison of insulin-like growth factor interaction with satellite cells and embryonic myoblasts derived from the turkey.

1. The interaction of insulin-like growth factors (IGFs) with receptors on clonal-derived turkey satellite cells and embryonic myoblasts was compared using competitive binding assays and affinity cross-linking analysis. 2. Although [125I]IGF-I and [125I]IGF-II were displaced similarly by IGF-I and IGF-II within cell lines (P greater than 0.05), displacement, and therefore dissociation constants, differed between cell lines (P less than 0.0001). 3. Receptor cross-linking analysis using iodinated IGFs suggests that both IGF-I and IGF-II interact with the type I receptor on turkey embryonic and posthatch myogenic cells.

Animals↗
PubMed1992

Vasorelaxation of rat thoracic aorta caused by two Ca(2+)-channel blockers, HA-22 and HA-23.

The pharmacological effects of HA-22 (2-(4'methoxyphenylmethyl)-3,4-dimethylpyrano[2,3-c]pyrazol- 6(2H)-one) and HA-23 (2-(2'-thienylmethyl)-3,4-dimethylpyrano[2,3-c]pyrazol-6(2H) -one) on rat isolated thoracic aorta have been examined. In high potassium medium (60 mM), Ca2+ (0.03-3 mM)-induced vasoconstriction was inhibited by HA-22 and HA-23 (10-100 micrograms mL-1). Cromakalim-relaxed aortic rings precontracted with 15 mM but not 60 mM K+. However, HA-22, HA-23 and verapamil produced a greater relaxation in 60 mM than in 15 mM K(+)-induced contraction. The tonic contractions elicited by KCl (60 mM) and Bay K 8644 (10(-7)M) were also relaxed by the addition of HA-22 and HA-23. The phenylephrine concentration-response curves displayed antagonism by HA-22 and HA-23 (10-100 micrograms mL-1) in a non-competitive manner. The caffeine (10 mM)-induced contraction and cAMP or cGMP levels were not affected by HA-22 or HA-23. It is concluded that HA-22 and HA-23 relaxed the rat aorta by suppressing the Ca2+ influx through both voltage-dependent and receptor-operated Ca2+ channels.

Animals↗
PubMed1988

Antibiotic-associated inhibition of steroidogenesis during short-term culture of ovarian tissues of the domestic fowl.

The effects of antibiotics on bovine luteinizing hormone (bLH)-stimulated output of androstenedione were examined in intact small white follicles (SWF, n = six hens), aliquots of 100,000 F1 and F2 theca cells (n = six hens), and aliquots of 10,000 F1 and F2 granulosa cells (n = eight hens). Cells and SWF were isolated from ovaries of Leghorn hens killed 20 h prior to ovulation and were incubated for 3 h in 1 mL of Medium 199 (Sigma Chemical Co., St. Louis, MO) at 37 C. Cells and follicles were incubated with 10 ng bLH and Penicillin-streptomycin (Pen-Strep; 20, 100, and 200 micrograms), gentamicin sulfate (gentamicin; 10, 50, and 100 micrograms), and fungizone (.5, 2.5, and 5.0 micrograms). Two control treatments consisted of tissues incubated alone (no bLH, no antibiotic) and tissues incubated with 10 ng bLH (no antibiotic). Androstenedione output by SWF and F1 and F2 theca cells and progesterone output by F1 and F2 granulosa cells were determined by radioimmunoassay of incubation media. The steroid contents of the incubation media were significantly increased in SWF and theca and granulosa cells with the addition of bLH. Neither Pen-Strep nor gentamicin significantly affected steroid output. Progesterone output by F1 and F2 granulosa cells was significantly reduced by the inclusion of fungizone. The inhibition of steroid output with the use of fungizone should be considered when using this antibiotic in studies of steroidogenesis in preparations of ovarian cells.

Amphotericin B↗
PubMed1987

Properties, biosynthesis and processing of a sulfur-rich protein in Brazil nut (Bertholletia excelsa H.B.K.).

An abundant seed protein, which is exceptionally rich in the sulfur-containing amino acids, methionine (18%) and cysteine (8%), is synthesized in Brazil nut embryos about 9 months after flowering. This sulfur-rich protein consists of two low-molecular-mass polypeptide components, a 9-kDa polypeptide and a 3-kDa polypeptide. The two-subunit polypeptides associate through disulfide linkage(s) to form a 12-kDa protein molecule. We have demonstrated through in vitro translation studies, using RNA from 9-month-old embryos, that the sulfur-rich protein is synthesized as a larger precursor polypeptide of 18 kDa. In addition, data from in vivo labelling studies of 9-month-old Brazil nuts suggest that there are two intermediate precursors of the sulfur-rich protein, one of 15 kDa and another of 12 kDa. One of these precursors, the 12-kDa polypeptide, accumulates for a 2-month period in the developing embryos. From these data we infer that at least three stepwise cleavages are involved in the maturation of the sulfur-rich protein from its 18-kDa precursor.

Amino Acids, Sulfur↗
PubMed1979

Coccidioidomycosis of the prostate gland and its therapy.

A case of disseminated coccidioidomycosis was diagnosed from a prostatic biopsy. Patients with sterile pyuria, prostatic nodules or symptoms of prostatitis who have lived in or traveled through an endemic area need careful evaluation of the lower genitourinary tract. Immunological treatment with a transfer factor currently is under investigation. Miconazole may offer a promise for future treatment of this fungal infection and, particularly, for patients with impaired renal function.

Amphotericin B↗
PubMedDate not supplied

Impaired gallbladder function in spinal cord injury on quantitative Tc-99m DISIDA cholescintigraphy.

BACKGROUND: Patients with spinal cord injury (SCI) have increased prevalences of gallstones and acute acalculous cholecystitis. A possible explanation for the increased prevalence of gallstone disease in SCI patients is decreased gallbladder motility causing gallbladder stasis, a known risk factor for gallstone disease. We investigated gallbladder function in SCI. METHODS: Twenty-five normal control subjects and 50 SCI patients were included in this study. Gallbladder function was measured by technium 99m-labeled imino-diacetic acid analogue (Tc-99m DISIDA) cholescintigraphy and represented by the filling fraction (FF) and the ejection fraction (EF). The SCI patients were assigned to subgroups: old versus young, female versus male, high- versus low-level injury, and long versus short injury duration. RESULTS: Forty-two percent of SCI patients had abnormal FFs and 54% of SCI patients had abnormal EFs. Significantly decreased FF and EF values were found in SCI patients, especially in those who were female and had high-level injuries. CONCLUSION: With the use of quantitative Tc-99m DISIDA cholescintigraphy, we found that SCI can significantly impair gallbladder function.

Adult↗
PubMedDate not supplied

Technetium-99m methylene diphosphonate scintimammography for evaluation of palpable breast masses.

Technetium-99m-methylene diphosphonate (Tc-99m MDP) scintimammography (SMB) was used to investigate palpable breast masses during routine presurgical bone scintigraphy, for women at high risk for cancer and who were candidates for surgery or excisional biopsy. Upright anterior and prone lateral views of the breasts were acquired from 65 women with palpable breast masses, 5-10 min after intravenous injection of 740 MBq of Tc-99m MDP. Breast cancer was histologically diagnosed in 50 women (77%) and benign disease was found in 15 women (23%). Of these 50 breast cancer patients, 44 (88%) showed abnormal MDP uptake in breasts. Among the 15 cases of benign lesions, only 1 (7%) showed abnormal MDP uptake in the breasts. The diagnostic sensitivity, specificity, and accuracy were 88%, 93%, and 89%, respectively, for the differentiation of malignant and benign breast masses. Scintimammography with Tc-99m MDP is a useful and cost-effective tool for differentiating malignant breast masses from benign breast masses.

Adult↗
PubMedDate not supplied

Technetium-99m tetrofosmin mammoscintigraphy findings related to the expression of P-glycoprotein mediated multidrug resistance.

We studied 30 patients with infiltrating ductal breast carcinomas to evaluate the relationship between the degree of accumulation of technetium-99m tetrofosmin (Tc-TETRO) and p-glycoprotein (Pgp) expression in breast tumor tissues. All of the 30 patients underwent Tc-TETRO mammoscintigraphy to calculate breast tumor uptake of Tc-TETRO to background (T/B) ratios before surgery or biopsy. Immunohistochemical analysis was performed to determine Pgp expression in the pathological specimens of the 30 breast tumors. The T/B ratios were significantly lower for tumors in 12 patients with positive Pgp expression (Group A) than for those in 18 patients with negative expression (Group B) (1.20 +/- 0.12 and 1.94 +/- 0.30, p < 0.05). Our results supported the opinion that Tc-TETRO mammoscintigraphy is helpful for determining in vivo the presence of multidrug resistance due to Pgp expression in breast carcinoma patients.

ATP Binding Cassette Transporter, Subfamily B↗
PubMedDate not supplied

Expression of drug resistance protein related to Tc-99m MIBI breast imaging.

Adjuvant and neoadjuvant chemotherapy is increasingly being used in the treatment of breast cancer patients. However, drug resistance plays an important role in chemotherapy failure in this cancer. The aim of this study was to determine the correlation between technetium-99m sestamibi (Tc-99m MIBI) breast imaging results and expression of the drug resistance proteins (p-glycoprotein (Pgp), Ki-67 and mutant p53) in human breast cancer tissues. Twenty-four breast cancer patients underwent Tc-99m MIBI breast imaging before surgery or biopsy. Protein expression was investigated by immunohistochemical studies on multiple nonconsecutive sections of surgery or biopsy samples. Tumor to background (T/B) ratios calculated by Tc-99m MIBI breast imaging were correlated with protein expression determined by immunohistochemical studies. The T/B ratios were significantly lower in 8 patients with positive Pgp expression (Group 1) when compared with 16 patients with negative Pgp expression (Group 2) (1.40 +/- 0.11 and 2.76 +/- 0.60, p < 0.05). However, the differences of T/B ratios between the patients with positive and negative Ki-67 mutant p53 expression were not significant. Our data confirmed that Tc-99m MIBI breast imaging is useful for determination of the presence of Pgp expression in breast cancer patients. No significant relationship between Tc-99m MIBI breast imaging results and Ki67/mutant p53 was found.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMedDate not supplied

Usefulness of technetium-99m tetrofosmin mammoscintigraphy as compared to mammography for detecting and differentiating palpable breast masses of young Taiwanese women.

Sixty young Taiwanese women with palpable breast masses detected by mammography and/or physical examinations underwent technetium-99m tetrofosmin (Tc-TETRO) mammoscintigraphy to assess its value for detecting and differentiating breast masses. The results showed that 42 of the 45 cases of breast carcinoma were detected by Tc-TETRO mammoscintigraphy. Fourteen of the 15 o benign breast lesions were differentiated by Tc-TETRO mammoscintigraphy. The diagnostic sensitivity, specificity, positive predictive value negative predictive value and accuracy of Tc-TETRO mammoscintigraphy were 93% 93% 98% 82% and 93% respectively. Thirty-eight of the 45 cases of breast carcinoma were detected by mammography. Twelve of the 15 of benign breast lesions were differentiated by mammography. The diagnostic sensitivity, specificity, positive predictive value, negative predictive value and accuracy of mammography were 84% 80% 93% 63% and 83% respectively. We concluded that Tc-TETRO mammoscintigraphy when compared to mammography significantly improves the accuracy of detection and differentiation of breast cancer in Taiwanese women.

Adult↗
PubMedDate not supplied

The role of Tc-99m methoxyisobutylisonitrile scintimammography as compared to mammography in evaluating palpable breast masses of Taiwanese women.

Eighty-one Taiwanese women (age range 31 to 79 years old) with palpable breast masses detected by mammography and or physical examination underwent technetium-99m methoxyisobutylisonitrile (Tc-99m-MIBI) scintimammography to assess its value in the detection of breast carcinomas and their differentiation from benign breast masses. The results showed that 58 of the 66 cases of breast carcinoma were detected by Tc-99m-MIBI scintimammography. Only 2 our of 15 patients with benign breast lesions had an abnormal scintimammographic finding. The mammography diagnosed 55 of the 66 cases of breast carcinoma, whilst 8 out of 15 patients with benign breast lesions had positive mammographic findings. The diagnostic sensitivity specificity and accuracy of Tc-99m-MIBI scintimammography were 88% 87% and 88%, respectively, whilst these parameters for mammography were 83%, 47% and 77%, respectively, regarding the differentiation of malignant from benign breast masses. We concluded that Tc-99m-MIBI scintimammography significantly improves the sensitivity and specificity for the detection of breast cancer in Taiwanese women with dense and small breasts.

Adult↗
PubMedDate not supplied

Tissue polypeptide specific antigen (TPS) as a tumor marker in nasopharyngeal carcinoma.

Tissue polypeptide specific antigen (TPS) is a new tumor marker that indicates tumor proliferative rate rather than tumor burden. The purpose of this study is to assess the clinical value of TPS in patients with nasopharyngeal carcinoma (NPC). Serum levels of TPS were measured in 60 patients with untreated NPC including 36 squamous cell carcinomas (SCC) and 24 undifferentiated carcinomas. NPC patients were separated into different subgroups based on the International Union Against Cancer (UICC) TNM classification system. Forty three healthy subjects without any evidence of malignancy or other systemic diseases were included as controls. The results showed that (1) the mean serum TPS level of the NPC patients was significantly higher than that of the healthy controls, (2) the mean serum TPS level of NPC patients with SCC was significantly higher than patients with undifferentiated carcinomas, (3) the mean serum TPS levels of NPC patients with higher TNM stages were significantly higher than those with lower TNM stages, (4) the overall diagnostic sensitivity of TPS for NPC is 58.3%, and (5) the overall diagnostic sensitivities of TPS in NPC patients with undifferentiated carcinomas and higher TNM stages were significantly higher than those with SCC and lower TNM stages. In conclusion, our results suggest that TPS may have a potential clinical role as a valuable tumor marker for NPC.

Adult↗
PubMedDate not supplied

Beta-2-microglobulin (beta 2M) as a tumor marker in nasopharyngeal carcinoma.

The purpose of this study was to assess the clinical value of serum beta-2-microglobulin (beta 2M) in patients with nasopharyngeal carcinoma (NPC). beta 2M levels were assayed in 145 Taiwanese patients with untreated NPC, including 100 squamous cell carcinomas (SCC) and 45 undifferentiated carcinomas. The 145 NPC patients were separated into different subgroups based on the International Union Against Cancer (UICC) TNM classification system. In addition, 50 healthy subjects without any evidence of malignancy or other systemic diseases were included as controls. The results showed that (1) the mean serum, beta 2M level of the 145 NPC patients was higher than that of the 50 healthy controls and (2) the mean serum beta 2M levels of NPC patients who were male, older, with SCC, with higher TNM stages, and with a shorter survival time were higher than those patients who were female, younger, with undifferentiated carcinomas, with lower TNM stages, and with a longer survival time. However, none of the differences were significant. In addition, the overall detecting sensitivity of beta 2M for NPC was only 24.1%, and the detecting sensitivities in NPC patients who were male, older, with SCC, with higher TNM stages, and with a shorter survival time were higher than those of patients who were female, younger, with undifferentiated carcinomas, with lower TNM stages, and with a longer survival time. However, these differences also were not significant. In conclusion, our results suggest the beta 2M may have limited clinical potential as a valuable tumor marker for NPC.

Adult↗
PubMedDate not supplied

Detection of esophageal carcinoma using single photon emission computed tomography with technetium-99m tetrofosmin.

Technetium-99m tetrofosmin (Tc-TF) a thallium-201 (Tl-201) and technetium-99m methoxy-isobutyl-isonitrile (Tc-MIBI) competitor, being used as a new radiopharmaceuticalfor myocardial imaging was assessed to understand its value in detecting esophageal carcinoma (Eso-Ca). Forty patients with Eso-Ca underwent Tc-TF single photon emission computed tomography (SPECT) of the chest. Meanwhile 15 controls also accepted Tc-TF SPECT of the chest for comparison. Among the 40 patients Tc-TF chest SPFCT detected Eso-Ca in 33 (82.5%) but not in 7 (17.5%). In contrast all 15 normal controls (100.0%) had negative Tc-TF chest SPECT Detection sensitivities were higher for tumors located in the middle portion of the esophagus for epidermoid ca and for tumors with poor differentiation when compared with tumors in the upper or lower portion for adenocarcinoma and tumors with moderate differentiation. However, the differences were not significant (p values < 0.05). Significantly higher detection sensitivity was found for tumors of larger size than for tumors of smaller size (p value < 0.05). Our results suggest that Tc-TF chest SPECT is a helpful test for detecting Eso-Ca especially larger tumors.

Adenocarcinoma↗
PubMedDate not supplied

Technetium-99m methoxy-isobutyl-isonitrile chest single photon emission computed tomography to detect mediastinal lymph node metastasis in patients with non-small cell lung cancer: comparison with computed tomography.

This study evaluated the clinical role of Tc-99m-methoxyisobtylisonitrile (Tc-MIBI) single photon emission computed tomography (SPECT) of the chest in the detection of mediastinal lymph node (MLN) metastasis in patients with non-small cell lung cancer (NSCLC). Twenty-five patients with proven NSCLC were enrolled in this study. Each of the patients received computed tomography (CT) of the chest and Tc-MIBI SPECT of the chest for presurgical staging. A postsurgical pathologic diagnosis was made and these patients were evaluated for the study of mediastinal lymph nde (MLN) involvement. Meanwhile, 10 volunteers also accepted Tc-MIBI SPECT of the chest for comparison. The results showed that the diagnostic sensitivity, specificity and accuracy of Tc-MIBI chest SPECT were 81.8%, 85.7% and 84% and for chest CT they are 36.3%, 85.7% and 64%, respectively. Our results indicated that Tc-MIBI chest SPECT was more sensitive and accurate than chest CT in the evaluation and detection of MLN involvement in the NSCLC patients.

Adenocarcinoma↗