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Biomedical subjects

Z D Zhang

Publications and source records attributed to Z D Zhang.

At least 37 records · Page 2Linked to original sources
PubMed1996

MTT assay overestimates human airway smooth muscle cell number in culture.

In this study, we evaluated the accuracy of the MTT (a tetrazolium salt) assay for cell counting by comparing it to haemocytometer. When airway smooth muscle cells were cultured in RPMI with fetal calf serum < or = 5%, no significant differences were observed in cell number counted by the two methods. For cells cultured in 10% serum, however, the result was 20% higher when counted by MTT assay. Rhodamine 123 uptake was similar in ASMCs cultured in the presence of serum at 5 and 10% indicating no difference in total mitochondrial activity per cell. Serum at > 5% may modulate the activity of enzymes responsible for reduction of MTT. Our results indicate that the MTT assay may not be accurate under certain conditions, especially when the treatment of cells can affect the enzymes that account for MTT reduction in addition to stimulating cell growth.

Bronchi↗
PubMed1994

The measurement of DNA content in Wilms' tumor and its clinical significance.

DNA content analysis with paraffin-embedded tissue was performed by flow cytometry on extracted nuclei from 42 Wilms' tumors. DNA histograms showed diploid in 13, tetraploid in 12, and aneuploid in 17. The frequency of DNA aneuploid was 40.48%. The 2- and 5-year survival rates were 84% and 75.16%, respectively, for patients with the DNA diploid pattern; the 2- and 5-year DNA aneuploid survival rates were 47.06% and 41.18% (P < .03 and P < .05), respectively. The 2- and 5-year survival rates for DNA tetraploid were in between, both 55.90%. For patients with stage I and II, the difference in the 2- and 5-year survival rates between DNA diploid plus tetraploid and DNA aneuploid was even more significant (P < .004 and P < .002, respectively). Thus, DNA aneuploid is an important indicator of poor prognosis in Wilms' tumor, especially for stages I and II.

Child↗
PubMed1994

[Clinical study on the type of operation in the treatment of acute necrotizing pancreatitis].

The type of operation in the treatment of acute necrotizing pancreatitis (ANP) is still controversial. Seventy-two surgical cases of ANP by using three different approaches since 1985 were analyzed retrospectively. The total mortality rate was 25%. The sump drainage was used in 28 cases, marsupialization in 11 cases and retroperitoneal drainage in 33 cases. The mortality rates were 25%, 36.4% and 21% respectively. The selection of approaches should be determined by clinical pathological types and by whether or not there is a retroperitoneal invasion. Sump drainage is a simple approach for ANP and is preferable in cases of sporadic focal necrosis. For extensive fusional pancreatic necrosis not complicated with retroperitoneal invasion, marsupialization is used, and in those with the invasion retroperitoneal drainage is the procedure of choice.

Acute Disease↗
PubMed1994

[Hepatopetal blood occlusion of half liver during hepatectomy in 29 patients].

In this study, hepatectomy was performed in 29 cases by temporarily occluding hepatopetal blood flow of only the half liver where the cancer was located. Results were compared with that of total hepatopetal blood occlusion in 14 cases. It was found that this method was less of postoperative complications, especially in cases with liver cirrhosis, and easy to perform.

Adult↗
PubMed1993

Characterization of [3H]ryanodine binding sites in smooth muscle of dog mesentery artery.

The ryanodine receptor has been widely demonstrated to be a Ca2+ release channel in both skeletal and cardiac muscle. Ryanodine also functionally affects Ca2+ release from an intracellular pool of smooth muscle. In the present study, both high and low affinity ryanodine binding sites are identified in dog mesenteric artery (with Kd 5 nM and 269 nM, respectively). [3H]ryanodine binding is not correlated with the density of innervation in different smooth muscles. This study provides direct evidence of the presence of ryanodine binding sites in dog mesentery artery. These ryanodine binding sites are of smooth muscle origin.

Animals↗
PubMed1993

Subcellular-membrane characterization of [3H]ryanodine-binding sites in smooth muscle.

The plant alkaloid ryanodine, known to interact selectively with the intracellular Ca(2+)-release channel in skeletal and cardiac muscles, has been repeatedly reported to affect smooth-muscle contractile functions that are consistent with its intracellular action at the Ca(2+)-release channel sites. Direct evidence for the binding of [3H]ryanodine to smooth-muscle membranes is sparse. Following our recent detailed characterization of functional effects of ryanodine and a preliminary report on the presence of [3H]ryanodine binding sites in rat vas deferens smooth muscle, we now report in this study a detailed characterization of binding of [3H]ryanodine to smooth muscle at the subcellular-membrane level. The ryanodine receptor in rat vas deferens muscle layer is primarily of smooth-muscle origin and is localized at the subcellular membrane site that is consistent with its role as a Ca(2+)-release channel in the sarcoplasmic reticulum (SR). Ryanodine binding to its receptor is Ca(2+)-dependent, with half-maximal binding occurring within the physiologically relevant cytosolic Ca2+ concentration. It is also sensitive to many factors, including change in Mg2+ concentration, ionic strength and osmolarity across the membrane vesicles. Agents known to inhibit (Ruthenium Red, Mg2+) or enhance (caffeine, Na+, K+) the Ca(2+)-induced Ca2+ release also inhibit or enhance the binding of ryanodine. Quantitative differences in ryanodine receptors exist among smooth muscles and do not seem to parallel their SR contents. Results from the present study indicate both the need and the basis for future investigations of the functional role of the ryanodine receptor in different smooth muscles.

Animals↗
PubMed1993

[Whole organ giant section histopathologic studies on breast cancer. III. Benign lesions in cancerous breast and near the tumor areas].

From April 1988 to January 1989, histopathologic studies of whole organ subserial sections was done in 200 mastectomy specimens of female breast carcinoma. The results indicated that extensive cystic proliferative disease (66%) and ductal epithelial hyperplasia (65%) were present in the cancer-bearing breasts. Most of them often distributed in two or more quadrants. Atypical hyperplasia was seen in 48% of all specimens, among them 54.2% was found in two or more quadrants. The incidence of atypical epithelial proliferation near the multiple primary foci (57%) was significantly higher than that near the main primary tumor (28.5%). Atypical hyperplasia adjacent to the tumor areas was commonly found more severely and had a tendency to transform into the malignancy. The authors concluded that the breast carcinoma is not an isolated lesion but a disease which arises from extensive epithelial hyperplasia of the breast. The malignant transformation usually appear in multiple sites within the same breast.

Adenofibroma↗
PubMed1992

[Histopathologic studies on whole organ giant section in breast cancer. II. Multicentricity and the chief primary lesion].

From April 1988 to January 1989, histopathologic studies on whole organ serial sections was done in 200 radical mastectomy specimens of female breast carcinoma. Results showed that the chief primary lesion measuring 0.5-1.0 cm or less in diameter had more multiple primary foci. With increasing size of the chief primary lesion, the incidence of multicentricity decreased. No significant relationship was found between the pathologic type of the chief primary lesion and multicentricity. But, in the non-invasive carcinoma, especially in carcinoma arising from the papillomatosis, invasive carcinoma of mucinous type and intraductal carcinoma with early infiltration were prone to develop multicentricity. The multicentricity in the second primary breast cancer was more common than in the first.

Adenocarcinoma, Mucinous↗
PubMed1991

[Whole organ giant section histopathologic studies on breast cancer--I. Multi-centric lesions].

From April 1988 to January 1989, histopathologic studies by whole organ subserial sections was done in 200 mastectomy specimens of female breast carcinoma. Multicentricity was demonstrated in 40 breast, with 68 multicentric lesions, an incidence of 20%. 80% of these 68 foci were clinically occult, measuring less than or equal to 1.0 cm. 72% was histologically noninvasive whereas only 28% invasive. Among the different pathologic types, intraductal carcinoma was more common (66%) than the others. Most (85%) of the multicentric lesions in the breast had one or two foci, rarely more than two. Multicentric lesions are usually distributed in the neighboring one or two quadrants of the primary cancer, seldom throughout three or four quadrants. They were less frequently seen in the same quadrant (22.5%). The multifocal growth was not related to age or menstrual status of the patient.

Adult↗
PubMed1991

[Effect of (-)-stepholidine on blood pressure and alpha-adrenoceptor agonists-, KCl- and CaCl2-evoked contractions of aortic strips].

Iv (-)-SPD lowered the blood pressure in anesthetized rat, the ED50 value was 5.1 +/- 2.5 mg.kg-1. In the experiments of rat and rabbit aortic strips, (-)-SPD 0.3-100.0 mumol.L-1 inhibited the contraction initiated by clonidine (alpha 2) and phenylephrine (alpha 1) and shifted the dose-response curve to the right parallely without change in maximum response. The inhibitory ratio of (-)-SPD acting on alpha 2/alpha 1 adrenergic receptors was about 7.2, and (-)-SPD thus was predominant inhibition on alpha 2 adrenergic receptors. In the experiment of aortic strips from reserpinized rabbits, the inhibition of (-)-SPD on contraction evoked by clonidine was diminished markedly. The results suggest that (-)-SPD stimulated mainly the alpha 2-adrenergic receptors of presynaptic nerve endings. Moreover (-)-SPD 1 mumol.L-1 inhibited the release of intracellular Ca2+ initiated by NE. (-)-SPD 3-30 mumol.L-1 blocked the voltage-dependent Ca2+ channel.

Animals↗
PubMed1991

Malignant melanoma of the biliary tract: a case report.

A 58-year-old man was seen with obstructive jaundice and discomfort in the upper abdomen. Computed tomographic and ultrasound examinations revealed a soft-tissue mass in the gallbladder. Cholecystectomy and choledochotomy revealed a soft black mass in the gallbladder and a second one in the intrapancreatic portion of the common bile duct. Each was diagnosed as malignant melanoma. Subsequently, a Whipple resection of the pancreas, duodenum, and distal bile duct revealed a melanoma circumferentially invading and obstructing the distal common duct. No lymph node or distant metastasis was identified. Repetitive searches for another primary site have been negative. The tumor apparently originated in the biliary tract. The patient remains almost well 2 years after diagnosis.

Bile Duct Neoplasms↗
PubMed1991

Ryanodine and the adrenergic, purinergic stimulation in the rat vas deferens smooth muscle: functional and radioligand binding studies.

The distribution of [3H]ryanodine binding in subcellular fractions isolated from rat vas deferens (RVD) paralleled that of NADPH cytochrome C reductase activity indicating an endoplasmic reticulum origin of the binding sites. Scatchard analysis of [3H] ryanodine binding indicated an homogenous site with a Kd value of 6.4 nM. The maximum number of ryanodine binding sites was 488 fmol of [3H]ryanodine per milligram of protein. Norepinephrine (NE) or ATP endogenously released after electrical field stimulation (tetrodoxin-sensitive responses), both produced a biphasic contraction of the RVD when the action of the other was blocked. When NE was the agonist (prazosin-sensitive response), the initial transient contraction was suppressed by 30 microM ryanodine whereas the secondary component was abolished by 2 microM nifedipine. When ATP was the agonist (P2 tachyphylaxis-sensitive response), both phases of the contraction were suppressed by 2 microM nifedipine. However, the initial phasic component of the contraction induced by endogenously released ATP was also inhibited by 30 microM ryanodine except at high stimulation frequency (10 Hz). Exogenously added NE and alpha, beta methylene ATP produced concentration-dependent contractions of the RVD. The effect of both agonists was inhibited by 2 microM nifedipine whereas 30 microM ryanodine had little effect except at high concentrations of NE. We conclude that ryanodine binding sites reside in RVD endoplasmic reticulum. There was a lack of uniformity in the effect of ryanodine and nifedipine against alpha adrenoceptor stimulation and purinoceptor stimulation indicating a difference in the stimulation-contraction coupling process between these two modes of stimulation.

Animals↗
PubMed1990

[Studies on the mechanism of gastric mucosal injury induced by water-immersion stress in rats].

Changes in the degree of gastric mucosal injury, gastric acid output, secretion of gastric barrier mucus and gastric motility were made in 5 groups of rat: I, Restraint alone plus saline under room temperature; II, Water-immersion plus saline; III, Water-immersion plus atropine (0.5 mg/kg); IV, Water-immersion plus phenoxybenzamine (10 mg/kg); V, Water-immersion plus pentobarbital (30 mg/kg). The results were as follows: (1) Water-immersion stress resulted in severe gastric mucosal lesions, an increase in the gastric acid output, a decrease in the secretion of gastric barrier mucus and an increase in gastric motility. (2) Atropine attenuated gastric mucosal injury significantly, inhibited gastric acid output and gastric motility, while gastric barrier mucus was increased. (3) Sodium pentobarbital also significantly attenuated gastric mucosal injury and inhibited gastric motility, but had no effect on gastric acid output. (4) Phenoxybenzamine failed to affect on gastric mucosal injury, gastric acid output, gastric barrier mucus secretion and gastric motility. These results suggest that the gastric hypercontractility, the reduction of gastric barrier mucus and the increase in gastric acid output participate in varying degrees in the formation of gastric mucosal injury induced by water-immersion stress, but when gastric motility is inhibited and gastric barrier mucus increases, only the existence of gastric acid can not induce severe gastric mucosal injury.

Animals↗
PubMed1990

Pharmacokinetics and autoradiography of [3H] or [14C]stepholidine.

After iv [3H]stepholidine (SPD) 12 MBq/kg, the concentration-time curve in rats was found to be a two-compartment open model. The distribution phase T1/2 alpha = 3.6 min, the elimination phase T1/2 beta = 168 min. The absorbed radioactivities of [3H] SPD in 15-30 min were 80-87%. The amounts of [3H]SPD bound to plasma protein, liver and kidney homogenates were estimated to be 37, 31, and 30%, respectively. During 3 d after ip [3H]SPD 50 MBq/kg, 56% of the radioactivity was excreted in urine and 5% in feces, thus, it suggested that [3H]SPD was mainly excreted by kidneys. After iv a single dose of [14C]SPD in mice, the whole-body autoradiography showed that [14C]SPD was rapidly distributed among various tissues. High radioactivities were found in kidneys, liver, brain, salivary glands, Harder's glands, heart blood and muscle at 2 min and intensively localized in kidneys and stomach mucosa at 30 min. The radioactivities in these tissues disappeared 4 and 8 h later, while that in intestine could not be detected 24 h later.

Animals↗