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Biomedical subjects

K R Zhou

Publications and source records attributed to K R Zhou.

18 recordsLinked to original sources
PubMed2006

Pancreatic adenocarcinoma: signs of vascular invasion determined by multi-detector row CT.

The purpose of this study was to analyse multi-detector row CT (MDCT) signs of peripancreatic arterial and venous invasion in pancreatic carcinoma. Among 101 patients with pancreatic carcinoma examined by MDCT, 54 candidates for surgery were pre-operatively evaluated for vascular invasion based on MDCT signs. The peripancreatic major vessels (including superior mesenteric artery, coeliac artery, common hepatic artery, superior mesenteric vein and portal vein) were examined carefully by surgeons during the operation. At surgical exploration, 78 of 224 vessels were invaded by tumour. The invaded peripancreatic major arteries (n = 29) and veins (n = 49) presented different MDCT signs: 43% of invaded veins (18/42, except for 7 occluded veins) were surrounded by tumour less than 50% of the vessel circumference compared with 97% (28/29) of the invaded arteries, which were surrounded by tumour more than 50% of the vessel circumference or were embedded in tumour (p<0.001). 69% (34/49) of the invaded veins had vascular stenosis or obliteration, compared with 41% (12/29) of the invaded arteries (p<0.05). Irregularity of the vein wall, 74% (31/42, except for 7 occluded veins); occurred more often than that of the artery wall, 45% (13/29) (p<0.05). In conclusion, the MDCT signs of peripancreatic arterial and venous invasion have different characteristics, which should be considered in pre-operative evaluation.

Adenocarcinoma↗
PubMed2004

The relationship between solitary pulmonary nodules and bronchi: multi-slice CT-pathological correlation.

AIM: To investigate the relationship between solitary pulmonary nodules (SPN) and bronchi and its value in predicting the nature of the SPN. MATERIALS AND METHODS: We performed volumetric targeted scans of 0.5 mm collimation with multi-slice computed tomography (MSCT), reconstructing multiplanar reconstructions (MPR), curved multiplanar reconstructions (CMPR) and surface-shaded display (SSD) images of bronchi in 78 consecutive patients with SPN (53 malignant and 25 benign) and correlated the findings with those of macroscopic and microscopic specimens. RESULTS: With this CT protocol, the third to seventh-order bronchi were shown continuously and very clearly in all patients. CT findings were consistent with those of specimens. CT demonstrated the relationship between the SPN and bronchi in 46 (86.8%) malignant and 18 (75.0%) benign nodules. Five types of tumour-bronchus relationships were identified with MSCT. Type I: the bronchus was obstructed abruptly by the SPN; type II: the bronchus penetrated into the SPN with tapered narrowing and interruption; type III: the bronchial lumen shown within the SPN was patent and intact; type IV: the bronchus ran around the periphery of the SPN with intact lumen; type V: the bronchus was displaced, compressed and narrowed by the SPN. Malignant nodules were most commonly of type I (58.5%), secondly of type IV (26.4%) and rarely of type V (1.9%). Benign nodules were most often of type V (36.0%), followed by type III (20.0%), type I (16.0%), and there were no type II. Types I, II and IV were more common in malignant nodules, whereas type V was seen more frequently seen in benign nodules (p<0.05). There was no statistically significant difference between the two groups regarding type III. CONCLUSION: Ultra-thin section with MSCT and MPR, CMPR and SSD reconstruction can improve the demonstration of the patterns of tumour-bronchus relationships, which can reflect the pathological changes of the nodules to some extent and help differentiate malignant from benign tumours.

Aged↗
PubMed1997

Eglin-c prevents monocrotaline-induced ventilatory dysfunction.

The present study was carried out to investigate the relationship between elastase and monocrotaline (MCT)-induced ventilatory dysfunction in rats. To accomplish this, we used an elastase inhibitor eglin-c to suppress the activity of endogenous elastase. Thirty-five young Sprague-Dawley rats were randomly divided into six groups: control, MCT, eglin-c(1), eglin-c(2), eglin-c(1) + MCT, and eglin-c(2) + MCT. Rats in the control group received no treatment. Each MCT rat received a single subcutaneous injection of MCT (60 mg/kg) 1 wk before the functional test. Each eglin-c(1) rat was intratracheally instilled with eglin-c (9 mg/rat) twice in 1 wk. Each eglin-c(2) rat was intratracheally instilled with eglin-c (9 mg/rat) five times in 1 wk. Both eglin-c + MCT groups were treated with the combination of eglin-c(1) or eglin-c(2) and MCT. In the MCT group, there were significant decreases in dynamic respiratory compliance, maximal expiratory flow rate at 50% total lung capacity, and the slopes of the maximal expiratory flow-%total lung capacity curve and the maximal expiratory flow-static recoil pressure curve. However, in the eglin-c(1) + MCT and eglin-c(2) + MCT groups, all of the above-mentioned MCT-induced changes were prevented. All ventilatory values of the eglin-c(1) and eglin-c(2) groups were not significantly different from those of the control group. These results demonstrate that eglin-c treatment prevents MCT-induced ventilatory dysfunction and suggest that endogenous elastase may play an important role in MCT-induced inflammation-mediated ventilatory abnormality.

Animals↗
PubMed1994

Oxygen radicals in exsanguination-induced bronchoconstriction of guinea pigs.

This study investigated the relationship between oxygen radicals and exsanguination-induced bronchoconstriction using antioxidant in guinea pigs. To accomplish this, two phases of studies were carried out. In phase 1, 34 guinea pigs weighing 342 +/- 11 g were divided into five groups: control (n = 7); acute dimethylthiourea (DMTU, n = 7); chronic DMTU (n = 8); superoxide dismutase (SOD, n = 6); and catalase (n = 6). Animals in the control group were not treated. DMTU, SOD, and catalase were employed for the scavenging of hydroxyl radical, superoxide anion, and hydrogen peroxide, respectively. Ten additional guinea pigs weighing 293 +/- 6 g were divided into two groups in phase 2: sham (n = 6) and chronic apocynin (n = 4). Animals in the sham group received injections of the vehicle, whereas apocynin was used to suppress the production of superoxide anion. All animals were anesthetized, sternotomized, and artificially ventilated. Before (baseline) as well as at fixed intervals 5-30 minutes following the exsanguination, the maximal expiratory flow maneuver was performed and the dynamic compliance (Cdyn) was obtained. Decreases in the maximal expiratory flow at 50% baseline vital capacity and Cdyn were used as indicators of bronchoconstriction. Exsanguination in the control and sham groups caused a gradual increase in airway constriction with time that was significantly ameliorated by chronic DMTU and chronic apocynin pretreatments but was not affected by other acute treatments. These results indicate that chronic treatment with antioxidants ameliorates exsanguination-induced, tachykinin-mediated airway constriction.

Analysis of Variance↗
PubMed1993

Capsaicin pretreatment attenuates monocrotaline-induced ventilatory dysfunction and pulmonary hypertension.

In view of bronchoconstrictor and proliferative effects of tachykinins (TKs; mainly substance P and neurokinin A), as well as increased TK release during tissue injury, we hypothesized that monocrotaline (MCT)-induced ventilatory dysfunction and pulmonary hypertension may be mediated via TKs. In phase 1 of the study (n = 19 rats), we tested and found that elevated lung substance P level and suppressed neutral endopeptidase activity occurred 1-2 wk post-MCT (60 mg/kg sc). Both phase 2 (n = 32) and phase 3 (n = 32) young Sprague-Dawley rats were divided into five groups: control, sham, capsaicin, MCT, and capsaicin + MCT. Rats in the control group received no treatment. Each sham rat received the vehicles. Chronic capsaicin treatment was used to deplete neuropeptides. Each MCT rat received a single injection of MCT 1 wk (phase 2) or 3 wk (phase 3) before the functional study. Each capsaicin + MCT rat received the MCT administration 3 days after the completion of capsaicin pretreatment. In the MCT group, there were significant decreases in dynamic compliance, quasi-static compliance, and the maximal expiratory flow rate at 50% total lung capacity in phase 2, which was accompanied by significant increases in pulmonary arterial pressure, the weight ratio of right ventricle/(left ventricle + septum), and the arterial medial wall thickness in phase 3. In the capsaicin + MCT group, however, all the above MCT-induced changes were significantly attenuated or abolished. All values from the sham and capsaicin groups were not significantly different from those of the control group. These data demonstrate that MCT induces pneumotoxicity, accompanied by elevated levels of substance P in the lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

alpha-Difluoromethylornithine attenuates monocrotaline-induced airway/lung dysfunction.

On the basis of the previous findings that alpha-difluoromethylornithine (DFMO, an inhibitor of ornithine decarboxylase, which is the rate-limiting enzyme in polyamine biosynthesis) treatment prevents monocrotaline-(MCT) induced pulmonary hypertension and that ventilatory dysfunction precedes pulmonary hypertension in MCT-treated rats, we hypothesize that MCT-induced changes in airway/lung function are polyamine dependent. To evaluate this hypothesis, in phase 1, 48 young Sprague-Dawley rats were evenly divided into four groups: control, DFMO, MCT, and DFMO + MCT. Each DFMO rat received DFMO in its drinking water (2%) for 11 days, with additional injections (400 mg/kg sc) on the 5th day. Each MCT rat received a single injection of MCT (60 mg/kg sc) 1 wk before the functional study. Each DFMO + MCT rat received the same DFMO and MCT treatments as above, and MCT was administered on the 5th day of the DFMO treatment. In the MCT group, there were marked rightward shifts in pressure-volume and maximal flow-static recoil (MFSR) curves and significant decreases in dynamic and quasi-static compliance, the maximal expiratory flow, slope of the MFSR curve, and the carbon monoxide diffusing capacity, as well as a significant increase in alveolar wall thickness. However, in rats treated with DFMO + MCT, most of MCT-induced changes were significantly attenuated. To evaluate whether MCT causes bronchoconstriction, a bronchodilator, terbutaline (0.2 mg/kg i.v.), was administered to control (n = 7) and MCT (n = 11) rats in phase 2. Terbutaline significantly reversed MCT-induced decreases in maximal expiratory flow and slope of the MFSR curve, whereas it did not alter these parameters in controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Obstruction↗
PubMed1991

Role of leukocyte depletion in noncholinergic bronchoconstriction of guinea pigs.

To test the role of leukocytes in the activation of afferent C-fibers in the lung, 33 guinea pigs, 18 control and 15 experimental or leukocyte depleted, were used. The leukocyte depletion was accomplished with an intraperitoneal injection of cyclophosphamide (100 mg/kg) 96 h prior to the study. On the day of the study, bronchial constriction was produced either by exsanguination (n = 17) or by capsaicin injection (16 micrograms/kg, i.v.) (n = 16) in anesthetized-paralyzed animals. Venous blood samples were collected for leukocyte counts. At 1-30 min following the above treatment, the maximal expiratory flow maneuver was performed and a decrease in the maximal expiratory flow at 50% baseline total lung capacity (Vmax50) was used as an index of bronchoconstriction. The leukocyte count decreased significantly following the pretreatment with cyclophosphamide [an average of 6217 +/- 612 (control) vs. 2242 +/- 334/mm3 (experimental)]. Exsanguination caused a gradual decrease in Vmax50 with time, indicating a temporal increase in bronchoconstriction. Capsaicin injection, on the other hand, caused an immediate (1 min) marked bronchoconstriction, which attenuated gradually with time. At a specific time point, leukocyte depletion did not produce any significant change in Vmax50 compared to the control group for both types of bronchoconstrictions. Based on these results, we conclude that leukocytes may play an insignificant role in the bronchoconstriction caused by the activation of afferent C-fibers in guinea pig lungs under our experimental conditions.

Animals↗
PubMed1990

[Hypotensive action of l-stepholidine in relation of dopamine receptors].

Spontaneously hypertensive (SH) and 2 kidney 1 clip hypertensive (2k1cH) rats were treated with ig l-stepholidine (SPD) 200 mg/(kg.d). Two wk after medication, the average blood pressure (BP) of SH and 2k1cH were 21.3 +/- 3.8 and 25.5 +/- 3.8 kPa lower than their controls respectively. The concentration of serum prolactin in treated SH and 2klcH decreased by 48% and 54%, respectively with its decrease of BP. The levels of plasma norepinephrine and epinephrine were increased and the excretion of urinary sodium was reduced or not changed. Since the level of prolactin is a biochemical index of central dopamine receptor (D-2) activity, so these results suggest that the regulation of central dopamine receptors may take part in hypotensive action of ig SPD and the peripheral dopamine receptors are neither agonistic to SPD nor involved in hypotensive action.

Animals↗
PubMed1985

The analgesic and respiratory depressant actions of metorphamide in mice and rabbits.

Metorphamide (MET) elicited a potent, dose-dependent analgesia and respiratory depression in mice and rabbits. MET induced-analgesia was naloxone reversible and potentiated by bestatin. Naloxonazine, a relatively selective mu 1 blocker, at certain dosage (50 micrograms per rabbit, icv), could abolish the analgesia but not the respiratory inhibition produced by MET. Our result indicates that mu 1 receptors mediate the MET induced-analgesia but not its respiratory effect. Since MET is a mu- and kappa-ligand with very low delta activity, the MET induced respiratory depression may be mediated by mu 2 or kappa binding sites.

Analgesics↗
PubMedDate not supplied

[Hepatic schistosomiasis. X-ray computed tomographic aspects. Apropos of 97 cases].

Ninety seven patients with liver cirrhosis of schistosomiasis were collected. Its CT findings and features were analysed on the clinicopathological basis including (1) the high percentage of the hepatomegaly and of the enlargement of the left lobe; (2) occurrence of deposition and calcification of eggs in large bowel wall (5/5), the portal vein system (22/97), the root of the mesentery (9/97) and the liver (93/97); (3) the variety and characteristics of the appearances of the intrahepatic calcification; (4) widened and fibrotic changes in the portal canal region. It was also noted that high percentage of hepatocellular carcinoma associated with this disease in the present series (25/97).

Adult↗