Biomedical subjects
Publications and source records attributed to G Sun.
DNA was extracted from human's and 15 different species of mammals' dried blood stains as well as from camel hair roots. DNA amplification was carried out using primers of Alu 9.1 and Alu 9.2. The results have indicated that this method can be used for the identification of human's dried blood stain under general condition.
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Fasting and postprandial plasma CCK levels of 102 normal subjects were measured by bioassay with dispersed rat pancreatic acini. The reference values ranged from 0 to 4.2 pmol/L (CCK-8 equivalents) for fasting and from 1.1 to 13.5 pmol/L for postprandial state. There was no significant difference between male and female, or in different age groups. The effects of CCK receptor antagonists of 3 different categories on CCK bioactivity in plasma measured by the bioassay were investigated. L 364,718 (5 nmol/L), proglumide (1.0 mmol/L), or Bt2-cGMP (0.1 mmol/L) was either extracted by SEP-PAK C18 cartridges together with human plasma containing 8 pmol/L of CCK-8, or added into the plasma extracts before the assay. The CCK bioactivity was inhibited by all of the 3 CCK antagonists. The action of L364,718 could be eliminated by the procedure of plasma extraction, but not of proglumide or Bt2-cGMP. It was suggested that CCK bioassay can be used even if L364,718 was administered. However, CCK cannot be measured accurately if there are proglumide or Bt2-cGMP in the plasma.
Serum TAG 72 concentrations of 110 normal subjects, 110 patients with benign diseases and 109 with malignant diseases were determined by a solid phase radioimmunoassay. Its levels in normal subjects were 1.6 +/- 1.5 u/ml (mean +/- SD, range 0-8.2 u/ml) and the cut-off limit was set at 4.6 u/ml. The positive rates in benign and malignant patients were 5.5% and 48.6%, respectively. Among the malignancies, 80.0% of ovarian and 63.6% of colon carcinomas had positive test results. The specificity for differentiating malignancies from benign diseases was 94.5% and the accuracy of diagnosis was 71.7%. The present study indicates that TAG 72 as a tumor marker is helpful in the diagnosis of malignancies.
Most cases of acute leukemia with deletions of chromosome 5q (5q-) are acute myelogenous leukemia. 5q- in acute lymphoid leukemia is rare. We studied a case of acute leukemia with 5q- using morphologic, cytochemical, immune and molecular techniques. Morphologic and cytochemical techniques were consistent with ALL (FAB L-2, PAS+, MPO-, ASD-). TdT was present. Immune studies suggested a T-cell phenotype (CD5+, CD7+); however, there was no rearrangement of the T beta-cell receptor gene. Surprisingly, the leukemia cells also expressed the CD13 myeloid antigen. Dual staining analysis showed co-expression of lymphoid and myeloid antigens on most cells. Based on these data and a review of previous reports we suggest that acute leukemia associated with the 5q- abnormality can occur in an immature stem cell resulting in a hybrid leukemia.
A sensitive and specific bioassay for the measurement of plasma cholecystokinin (CCK) is reported. CCK was extracted from plasma by SEP-PAK cartridges and the extracts were measured for CCK levels based on their ability to stimulate amylase release from dispersed rat pancreatic acini. Plasma CCK levels as low as 0.86 pmol/L (CCK-8 equivalent) were detectable. Gastrin in physiological concentration did not affect the bioassay. The amylase release stimulated by plasma extracts was abolished by Bt2-cGMP, a specific CCK receptor antagonist, indicating that there might be no secretin or VIP in plasma extracts. With this bioassay, fasting and postprandial plasma CCK levels of 11 normal volunteers were determined. The fasting level of CCK was 0.95 +/- 0.22 pmol/L (mean +/- SE). It increased to 2.98 +/- 0.67 pmol/L 15 minutes after feeding and remained significantly higher than the fasting level during a 60-minute period.
Sulfide has a sensitive polarographic wave in the system of NaOH-EDTA-triethanolamine. The addition of triethanolamine to the system improved the shape of the wave and increased the sensitivity. The peak current was directly proportional to the concentration of sulfide in the range of 0.002-5.000 ppm. The detection limit for water sample was 2 ppb, and the relative standard deviation and recovery were 2.3-7.2% and 94.0-102.0%, respectively. The proposed method is simple, accurate, sensitive and reproducible.
A new automatic spatiotemporal algorithm has been developed for detecting QRS onset and offset in body surface potential mapping. The new algorithm, based on a spatial and temporal approach, along with three other algorithms (total energy, 3-lead, and median), was tested in 73 normal and abnormal patients. The reference or gold standard onset and offset times were determined visually by two experienced investigators. The results demonstrate that the new method is less sensitive to noise, to the temporal overlap of the QRS and other components, and to the spatial location changes of QRS initial and final activation. The spatiotemporal method resulted in very consistent findings, with a standard deviation of less than one third of the standard deviation in the next best method.
This paper describes a technique of DNA amplification in vitro and its application on sex identification of human dried bloodstains. Dried bloodstains (8 males and 8 females) were prepared on filter paper, and then DNA was extracted. Target DNA sequences (Y-3.4kb repeat and Alu-repeat) were amplified by polymerase chain reaction (PCR) with two pairs of primers (Y1.1, Y1.2 and Alu9.1, Alu9.2). Amplification products were obtained in 8 male's bloodstains with the primers Y1.1 and Y1.2, but not in 8 female's bloodstains; and in 4 male's and 4 female's bloodstains with Alu9.1 and Alu9.2.
From 1978 to 1987, 1108 cases of bladder tumors were admitted in 19 hospitals in Tianjing, among which 91.8% (997 cases) was bladder transitional cell carcinoma and accounted for 10% of all the inpatients admitted at the urology department during the same period. The conditions of the diagnosis and treatment of the bladder transitional carcinoma are analysed, the present problems and the improvement opinions are suggested in the present report.
We investigated a possible role of secretin in the mechanism of exocrine pancreatic secretion after exclusion of pancreatic juice from the intestine in anesthetized rats. Diversion of pancreatic juice from the duodenum resulted in a significant increase in plasma secretin concentration from 0.76 +/- 0.39 pM at 0 time to 3.09 +/- 0.30 pM at 4 h after diversion. This increase in secretin coincided with a steady but significant increase in pancreatic secretion of volume and bicarbonate. Intraduodenal administration of fresh pancreatic juice completely reversed the diversion-induced increases in both plasma secretin and pancreatic secretion. Intravenous injection of a rabbit-antisecretin serum blocked the increase of pancreatic secretion during diversion of pancreatic juice from the duodenum. Thus, we conclude that endogenous secretin is involved in a hormonal mechanism regulating increased pancreatic exocrine secretion in pancreatic juice-diverted rats.
The technical aspects of a multiple-purpose cardiac mapping system are presented. The authors begin with a brief history of hardware and software development and then concentrate on the major problems in acquiring high-quality recordings from the torso surface or from the epicardial surface and on the processing of the signals for display of color maps or other analysis. To achieve the desired adaptability to a variety of cardiac applications and experiments, they incorporated three parallel microprocessors that can record the signals from 240 electrodes and simultaneously provide display and analysis of the incoming cardiac data. While the parallel processors and modular software offer computational and flexibility advantages, the user interacts with an ordinary AT-compatible computer. This discussion is not a survey of the systems used in the many research laboratories or specific cardiac applications but is focused on experience in developing the specific hardware for such a multi-purpose instrument, and less specifically on the software that makes the system easy to use and adaptable to a variety of experimental and clinical situations.
We used an avidin-biotin complex immunoperoxidase technique with various monoclonal antibodies to determine Langerhans cell densities, class II antigen expression on keratinocytes, and phenotypes of other infiltrating cells in several malignant and benign epithelial tumors of the skin. Our observations indicate (1) there are few Langerhans cells in nests of basal cell carcinoma and squamous cell carcinoma; (2) there are increased Langerhans cell densities in seborrheic keratoses, verrucous epidermal nevus, and Bowen's disease; (3) there is an expression of class II molecules on the keratinocytes and cancer cells of basal cell carcinoma, squamous cell carcinoma, Bowen's disease, seborrheic keratosis, and verrucous epidermal nevus; and (4) there is a netlike staining of the keratinocyte surface with OKM5 in the epidermal lesion of seborrheic keratosis, verrucous epidermal nevus, and Bowen's disease, as well as in the epidermis adjacent to the basal cell carcinoma and squamous cell carcinoma nests.
Among 30 patients with islet cell neoplasms or hyperplasia who exhibited marked gastric acid hypersecretion and peptic ulceration and/or diarrhea, fasting plasma gastrin concentrations were less than 150 pg/ml in 11 patients, whereas the remaining 19 patients had hypergastrinemia. Plasma extracts from seven of these 11 patients were assayed for acid secretagogue activity in rats. All seven plasma extracts had secretagogue activity that was not found in the plasma extracts of ten patients with ordinary duodenal ulcer disease. Each of the tumor or pancreatic tissue extracts obtained from nine patients exhibited secretagogue activity in rats even though tissue gastrin content was 101.9 pmol (213.8 ng).g-1 or less. The secretagogue activity of the tumor extracts was confirmed in conscious gastric fistula dogs. The tumors' secretagogue activity, in contrast to gastrin, was destroyed by trypsin. It was eluted between porcine motilin and human gastrin I from a Sephadex G-50 (Pharmacia LKB Biotechnology, Inc., Piscataway, NJ) superfine column and was not retained by CM-cellulose, at pH 8.5. Its retention time during reverse phase HPLC on a C18 column also differed from those of G17 and G34. Thus, this secretagogue activity appeared mediated by a small, acidic peptide with a molecular size of about 2000 to 3000 daltons. The present study indicates that plasma and tumor extracts of these 11 patients contain a gastric acid secretagogue activity mediated by a nongastrin peptide. We suggest that what may be a distinct clinical entity associated with endocrine neoplasms of the pancreas should be considered in the face of excessive acid hypersecretion without fasting hypergastrinemia.
Chloroplast thylakoid protein phosphatase activity was measured using (32)P-labeled histone as an exogenous substrate and an assay of the (32)Pi released involving formation of a phosphomolybdate complex and organic extraction. The activity was liberated from wheat (Triticum aestivum) thylakoids by washing the membranes in NaCl-containing solutions followed by centrifugation. The liberated phosphatase activity had a pH optimum of approximately 6.75, was inhibited by addition of 10 millimolar EDTA or EGTA, and was stimulated by addition of millimolar amounts of dithiothreitol, magnesium, manganese, or calcium ions. The rate of thylakoid protein dephosphorylation was decreased following liberation of a portion of the protein phosphatase activity and was increased by addition of salt-liberated phosphatase fraction. These results suggest that at least a portion of wheat thylakoid protein phosphatase is a peripheral, rather than an integral, membrane protein.
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Pancreatic exocrine secretion was evoked by electrical stimulation of the vagus nerves (EVS) in dogs to determine whether a gut hormone was responsible for the pancreatic stimulatory activity. In 39 dogs, pancreatic juice was continuously collected to measure volume, bicarbonate, and amylase output, while portal and femoral venous plasma concentrations of gastrin, cholecystokinin (CCK), vasoactive intestinal polypeptide (VIP), and pancreatic polypeptide (PP) were determined by radioimmunoassay. EVS produced a significant increase in the pancreatic secretion. Although concentrations of all four peptides significantly increased in plasma, only CCK at the concentration in venous circulation was bioactive in dispersed rat pancreatic acini preparations. This bioactivity of CCK was completely blocked by CR 1409, a CCK-receptor antagonist. The pancreatic secretion by EVS was reduced significantly by intravenous MK-329 (formerly L364,718) to as low as 22% of control values and was completely suppressed by intravenous atropine. The increment in plasma CCK by EVS was also significantly suppressed by atropine. The present study indicates that increased pancreatic secretion by EVS is in part mediated by endogenous CCK.
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