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Biomedical subjects

B Y Zheng

Publications and source records attributed to B Y Zheng.

7 recordsLinked to original sources

Detection of adeno-associated virus type 2 genome in cervical carcinoma.

Adeno-associated virus (AAV) can impair the replication of other viruses. Adeno-associated virus seroprevalences have been reported to be lower among women with cervical cancer. In-vitro, AAV can interfere with the production of human papillomavirus virions. Adeno-associated virus-2 DNA has also been detected in cervical cancer tissue, although not consistently. To evaluate the role of AAV infection in relation to invasive cervical cancer, we performed a nested case-control study within a retrospectively followed population-based cohort. A total of 104 women who developed invasive cervical cancer on average 5.6 years of follow-up (range: 0.5 months-26.2 years) and 104 matched control-women who did not develop cervical cancer during the same follow-up time were tested for AAV and human papillomavirus by polymerase chain reaction. At baseline, two (2%) case-women and three (3%) control-women were positive for AAV-2 DNA. At the time of cancer diagnosis, 12 (12%) case-women and 3 (3%) matched control-women were positive for AAV-2 DNA. Persisting AAV infection was not evident. In conclusion, AAV-2 DNA was present in a low proportion of cervical cancers and we found no evidence that the presence of AAV in cervical smears of healthy women would be associated with reduced risk of cervical cancer.

Adult↗

Small intestinal glucoamylase deficiency and starch malabsorption: a newly recognized alpha-glucosidase deficiency in children.

To determine the prevalence of short polymers of glucose and starch malabsorption caused by small intestinal glucoamylase deficiency in children with chronic diarrhea, we studied small bowel biopsy specimens from 511 children (aged 1 month to 9 years) with chronic diarrhea evaluated at 54 medical centers. Glucoamylase and disaccharidase (lactase, sucrase, maltase, and palatinase) enzyme assays were performed. Of the 511 children, 15 had glucoamylase deficiency. Six who had significant small intestinal mucosal injury and disaccharidase deficiencies were defined as having secondary glucoamylase deficiency; the other nine patients with normal mucosal morphologic features were defined as having primary glucoamylase deficiency. Secretin tests showed normal pancreatic amylase values for age in all seven children tested. Four of them had abnormal findings on tolerance tests for starch and short polymers of glucose (rise in blood glucose concentration: < 20 mg/dl) and reducing substances in stools, and three of these four had symptoms of intolerance (abdominal distention, flatulence, and diarrhea). All seven patients responded to a starch elimination diet. After reintroduction of a starch diet, diarrhea recurred in four patients; this was alleviated 48 hours after reelimination of starch. We conclude that intestinal glucoamylase deficiency is present in some patients with chronic diarrhea.

Carbohydrate Metabolism, Inborn Errors↗

Effect of perfusion of oral rehydration solutions containing glucose polymers from corn on disaccharidases and mucosal morphology in rat small intestines.

This study aims to determine the effect of glucose and glucose polymers (GP) from corn in oral rehydration solutions (ORS) on disaccharidases and morphometric measurements in small intestinal mucosa of rats. ORS containing standard composition of salts as in WHO ORS and 2, 5, or 10 per cent glucose or GP [initial glucose polymers, long chain (> 9 molecules) and short chain (2-9 molecules) glucose polymers] from corn were infused into the duodenum of 72 Sprague-Dawley rats (250-350 g). Six rats were sham operated as controls. The levels of lactase, sucrase, maltase, palatinase, and glucoamylase enzymes were higher in rats infused with ORS-containing glucose or GP than control rats. Villus height, villus width, and crypt height in corresponding segments of duodenum, jejunum, and ileum were not significantly different between rats perfused with ORS containing glucose polymers from corn and those with ORS containing glucose. ORS containing GP from corn have no adverse effects on small intestinal enzymes and morphometric measurements.

Animals↗

Absorption of glucose polymers from rice in oral rehydration solutions by rat small intestine.

BACKGROUND: This study aims to determine the effect of replacing glucose in oral rehydration solution (ORS) with starch hydrolysates from rice on absorption in the small intestine and levels of glucose in portal venous blood and on disaccharidase levels and morphometric measurements in intestines of rats. METHODS: ORS containing standard composition of salts and 2% glucose (WHO ORS) or 2%, 5%, or 10% starch hydrolysates were infused into duodena of 60 Sprague-Dawley rats (250-350 g). Portal venous blood glucose levels were determined at 0, 30, 60, 90, and 120 minutes. RESULTS: Significantly larger areas under the curve of glucose absorption (AUCs) were produced by ORS containing 10% unfractionated starch hydrolysates (123.2 +/- 3.8), 2%, 5%, and 10% starch hydrolysates with long-chain ( > 9 molecules) glucose polymers (109.5 +/- 10.6, 109.3 +/- 7.4, and 115.3 +/- 7.1, respectively), and 5% and 10% starch hydrolysates with short-chain (2-9 molecules) glucose polymers (124.4 +/- 6.1 and 128.1 +/- 6.8). ORS with 2% and 5% unfractionated starch hydrolysates and 2% short-chain glucose polymers produced AUCs comparable with those of WHO ORS (96.48 +/- 5.7). Disaccharidase levels and morphometric measurements were not significantly different. CONCLUSIONS: Starch hydrolysates from rice containing glucose polymers can be used in ORS in higher concentrations than glucose to provide higher caloric density without increased osmolality.

Animals↗

An optimal rice-based oral rehydration solution: the effect of different concentrations of amylase on production of short chain polymers of glucose.

As part of a plan to develop a rice-based oral rehydration solution containing short polymers of glucose instead of glucose, we determined the concentration of amylase that would yield the largest amount of short chain polymers. Thai rice (25 g) was boiled with 500 ml of distilled water for 30 min. Of 200 ml supernatant rice water obtained, 100 ml were digested with different amounts of amylase after cooling to 50 degrees C for 60 min, boiled for 5 min, and centrifuged (10,000 g, 25 degrees C) for 60 min. The resulting supernatant (80 ml) was freeze-dried; 1.75 g of the powder obtained were dissolved in 3.5 ml of water, passed through a Bio-Gel P2 column to separate short chain polymers (2-9 molecules of glucose) and long chain polymers (> 9 molecules of glucose), which were identified by spectrophotometry (lambda = 190 nm) or by high performance liquid chromatography. Ten mg of amylase (equivalent to 12,000 modified Wohlgemath units) per 100 ml of rice water was optimal for the production of short polymers of glucose from rice.

Amylases↗