Evaluation of renal function in chronic kidney disease (CKD) by mDIXON-Quant and Amide Proton Transfer weighted (APTw) imaging.

BACKGROUND: Chronic kidney disease (CKD) is a long-term condition that affects >10% of the adult population worldwide. Noninvasive assessment of renal function has important clinical significance for disease diagnosis and prognosis evaluation. OBJECTIVE: To explore the value of mDIXON-Quant combined with amide proton transfer weighted (APTw) imaging for accessing renal function in chronic kidney disease (CKD). MATERIALS AND METHODS: Twenty-two healthy volunteers (HVs) and 30 CKD patients were included in this study, and the CKD patients were divided into the mild CKD (mCKD) group (14 cases) and moderate-to-severe CKD (msCKD) group (16 cases) according to glomerular filtration rate (eGFR). The cortex APT (cAPT), medulla APT (mAPT), cortex R2⁎ (cR2⁎), medulla R2⁎ (mR2⁎), cortex FF (cFF) and medulla FF (mFF) values of the right renal were independently measured by two radiologists. Intra-group correlation coefficient (ICC) test was used to test the inter-observer consistency. The analysis of variance (ANOVA) was used to compare the difference among three groups. Mann-Whitney U test was used to analyze the differences of R2⁎, FF and APT values among the patient and HV groups. Area under the receiver operating characteristic (ROC) curve (AUC) was used to analyze the diagnostic efficiency. The corresponding threshold, sensitivity, and specificity were obtained according to the maximum approximate index. The combined diagnostic efficacy of R2⁎, FF, and APT values was analyzed by binary Logistic regression, and the AUC of combined diagnosis was compared with the AUC of the single parameter by the Delong test. RESULTS: The cAPT value of the HV, mCKD and msCKD groups increased gradually. The mAPT value and cR2⁎ values of the mCKD and msCKD groups were higher than those of the HV group, while the mFF value of the mCKD group was lower than HV group (all P < 0.05). The cAPT and mAPT values showed good diagnostic efficacy in evaluating different degrees of renal damage, while cR2⁎ and mFF values showed moderate diagnostic efficacy. When combining the APT, R2⁎, and FF values, the diagnostic efficiency was significantly improved. CONCLUSION: mDIXON-Quant combined APTw imaging can be used for improved diagnosis of CKD.

[Tuberculosis presenting as gastrointestinal perforation and large confluent pulmonary cavities: a case report].

We report an unusual case presented as acute gastrointestinal perforation and large confluent pulmonary cavities. A 23-year-old male was admitted to the emergency department with complaints of abdominal pain for 1 month, which exacerbated for 1 day. He also reported a 3-month history of diarrhea and productive cough. Computed tomography (CT) scan showed multiple large confluent cavities in the lung, along with massive free gas in the abdomen suggesting gastrointestinal perforation. Exploratory laparotomy was performed and affected bowel segment was resected. His sputum examination was positive for both acid-fast staining and Mycobacterium tuberculosis complex gene (Xpert) testing. Pathology of small intestine revealed micro-abscess formation and was positive for acid-fast bacilli. A final diagnosis of pulmonary tuberculosis and intestinal tuberculosis was made.

[Clinical characteristics of 272 437 patients with different histopathological subtypes of primary esophageal malignant tumors].

Objective: To characterize the histopathological subtypes and their clinicopathological parameters of gender and onset age by common, rare and sparse primary esophageal malignant tumors (PEMT). Methods: A total of 272 437 patients with PEMT were enrolled in this study, and all of the patients were received radical surgery. The clinicopathological information of the patients was obtained from the database established by the State Key Laboratory of Esophageal Cancer Prevention & Treatment from September 1973 to December 2020, which included the clinical treatment, pathological diagnosis and follow-up information of esophagus and gastric cardia cancers. All patients were diagnosed and classified by the criteria of esophageal tumor histopathological diagnosis and classification (2019) of the World Health Organization (WHO). The esophageal tumors, which were not included in the WHO classification, were analyzed separately according to the postoperative pathological diagnosis. The χ2 test was performed by the SPSS 25.0 software on count data, and the test standard α=0.05. Results: A total of 32 histopathological types were identified in the enrolled PEMT patients, of which 10 subtypes were not included in the WHO classification. According to the frequency, PEMT were divided into common (esophageal squamous cell carcinoma, ESCC, accounting for 97.1%), rare (esophageal adenocarcinoma, EAC, accounting for 2.3%) and sparse (mainly esophageal small cell carcinoma, malignant melanoma, etc., accounting for 0.6%). All the common, rare, and sparse types occurred predominantly in male patients, and the gender difference of rare type was most significant (EAC, male∶ female, 2.67∶1), followed with common type (ESCC, male∶ female, 1.78∶1) and sparse type (male∶ female, 1.71∶1). The common type (ESCC) mainly occurred in the middle thoracic segment (65.2%), while the rare type (EAC) mainly occurred in the lower thoracic segment (56.8%). Among the sparse type, malignant melanoma and malignant fibrous histiocytoma were both predominantly located in the lower thoracic segment (51.7%, 66.7%), and the others were mainly in the middle thoracic segment. Conclusion: ESCC is the most common type among the 32 histopathological types of PEMT, followed by EAC as the rare type, and esophageal small cell carcinoma and malignant melanoma as the major sparse type, and all of which are mainly occur in male patients. The common type of ESCC mainly occur in the middle thoracic segment, while the rare type of EAC mainly in the lower thoracic segment. The mainly sparse type of malignant melanoma and malignant fibrous histiocytoma predominately occur in the lower thoracic segment, and the remaining sparse types mainly occur in the middle thoracic segment.

[Effect of convection enhanced delivery on the microstructure of brain extracellular space in aged rats].

OBJECTIVE: To compare the changes of extracellular space (ECS) structure and local drug distribution in adult brain and aged brain at different drug delivery rates in minimally invasive treatment of encephalopathy by convection enhanced delivery (CED) via ECS pathway. METHODS: Thirty-six SD male rats were divided into adult rats group (2-8 months, n=18) and aged rats group (18-24 months, n=18) according to the age of the month. According to the drug rates (0.1 µL/min, 0.2 µL/min, and 0.3 µL/min), they were randomly divided into 3 subgroups, 6 in each subgroup. Gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) with a concentration of 10 mmol/L were introduced into the caudate nucleus of each group of rats by stereotactic injection. Tracer-based magnetic resonance imaging (MRI) was used to dynamically monitor the diffusion and distribution images of the Gd-DTPA in the brain interstitial system (ISS). Using the self-developed MRI image measurement and analysis system software to process and analyze the obtained images, the diffusion coefficient, clearance rate, volume fraction, and half-life of each group of rats in the caudate nucleus ECS could be acquired. The effects and differences of drug clearance and ECS structural function in the brain of aged rats and adult rats were compared and analyzed at different drug delivery rates. Magnetic tracer DECS-mapping technique was used to observe the distribution and drainage of tracer in caudate nucleus. RESULTS: At the injection rate of 0.1 µL/min, the volume fraction in the aged rats was increased compared with that in the adult rats (18.20%±0.04% vs. 17.20%±0.03%, t=3.752, P=0.004), and the degree of tortuosity was decreased (1.63±0.04 vs. 1.78±0.09, t=-3.680, P=0.004), the drug clearance rate was decreased [(1.94±0.68) mm2/s vs. (3.25±0.43) mm2/s, t=-3.971, P=0.003], and the molecular diffusion in ECS was increased [(3.99±0.21)×10-4 mm2/s vs. (3.36±0.37)×10-4 mm2/s, t=3.663, P=0.004]. When the rate of injection increased to 0.2 µL/min, the drug clearance in ECS of the aged rats was slowed down [(2.53±0.45) mmol/L vs. (3.37±0.72) mmol/L, t=-1.828, P=0.021]. However, there were no significant differences in volume fraction, molecular diffusion in ECS and macroscopic drug metabolism parameters. When the rate of injection increased to 0.3 µL/min, the volume fraction in the aged rats was decreased (17.20%±0.03% vs. 18.20%±0.05%, t=-0.869, P=0.045), and the drug clearance rate in ECS was significantly accelerated [(4.04±0.76) mmol/L vs. (3.26±0.55) mmol/L, t=1.786, P=0.014], and there was no significant difference in tortuosity and the rate of molecular diffusion in the ECS. CONCLUSION: The drug clearance and ECS structural parameters of brain ECS in aged brain with CED administration were changed at different rates, and it has the least effect on ECS in the aged brain at the injection rate of 0.2 µL/min. For the application of CED for the treatment of encephalopathy, we should consider the influence of factors such as age and injection rate, and provide reference for the development of individualized clinical treatment plan for minimally invasive treatment of encephalopathy via ECS pathway.

HSP20-mediated cardiomyocyte exosomes improve cardiac function in mice with myocardial infarction by activating Akt signaling pathway.

OBJECTIVE: To explore the role of heat shock protein 20 (HSP20)-mediated cardiomyocyte exosomes in the cardiac function in mice with myocardial infarction via the activation of the protein kinase B (Akt) signaling pathway. MATERIALS AND METHODS: A total of 30 mice were enrolled to establish the model of myocardial infarction. Next, these mice were divided into three groups, namely Blank group (healthy mice), Model group (mouse models of myocardial infarction), and HSP20 group (mouse models of myocardial infarction transfected with lentivirus to overexpress HSP20). After that, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining assay was performed to detect myocardial apoptosis. Reactive oxygen species (ROS) accumulation in myocardial tissues was determined via dihydroethidium (DHE) staining assay. Western blotting was employed to analyze the expression level of Akt. The expression levels of inflammatory factors tumor necrosis factor-alpha (TNF-α) and interleukin 1 beta (IL-1ß) in HSP20-mediated cardiomyocyte exosomes were measured through quantitative real time polymerase chain reaction (qRT-PCR). RESULTS: Compared with that in Blank group, the number of cardiomyocyte exosomes was increased in Model group and HSP20 group under anoxic conditions (p<0.05). The results of quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) proved that the HSP20 messenger ribonucleic acid (mRNA) expression in mediated cardiomyocyte exosomes was significantly lower in Model group than that in Blank group (p<0.05), while in HSP20 group, it was overtly higher than that in Model group but clearly lowered compared with that in Blank group (p<0.05). The protein expression of Akt in cardiomyocyte exosomes was evidently decreased in Model group compared with that in Blank group (p<0.05), while it was notably increased in HSP20 group compared with that in Model group (p<0.05). In comparison with Blank group, Model group had significantly elevated mRNA expression levels of TNF-α and IL-1ß. The mRNA expression levels of TNF-α and IL-1ß in HSP20 group were remarkably lower than those in Model group (p<0.05). The results of TUNEL assay revealed that the overexpression of HSP20 affected myocardial apoptosis. The myocardial apoptosis index in Model group [(38.42±2.52) %] was higher than that in Blank group [(9.74±1.21) %], HSP20 group had a significantly decreased myocardial apoptosis index [(22.36±2.13) %] in comparison with Model group (p<0.05). In accordance with DHE staining comparison, the accumulation of ROS in myocardial tissues in Model group was significantly higher than that in Blank group (p<0.05) and HSP20 group (p<0.05). CONCLUSIONS: We demonstrated that HSP20-mediated cardiomyocyte exosomes activate the AKT signaling pathway, repress TNF-α and IL-1ß factors, and alleviate myocardial infarction.

[Effect of nutrition quality of breakfast on satiety among young white-collar workers].

Objective: To analyze the effect of breakfast nutrition quality on the satiety among young white-collar workers. Methods: A total of 278 subjects were recruited from two cities, Shenyang and Chongqing, in June 2015. The inclusion criteria: white-collar workers aged 25-45 years involved mainly in office work, who did not experience major changes, and individuals who should follow the study protocol and sign the informed consent form. The study employed a three-phase crossover design trial. Each participant received nutritional-adequate breakfast, nutritional-inadequate breakfast, and no breakfast treatment on the basis of assignment to one of three sequences. The breakfast time was once a week and then changed, all participants underwent the tests for three successive weeks. At last, we compared the effect of participants to consume different nutritional quality on satiety sense and hunger sense. Results: A total of 232 participants completed three successive breakfast intervention studies, the age of participants was (35.2 ± 7.9) years, comprised of 48.7% male (n=113). The numbers of participants of aged 25-35 year-old and aged 36-45 were 118 and 114, respectively. Satiety scores of nutrition-adequate breakfast group, nutrition-inadequate breakfast group and no breakfast group were 63.5±14.7, 53.1±10.2 and 36.4±7.2, respectively (P<0.05). In nutrition-inadequate breakfast group and no breakfast group, male subjects scored significantly higher than female subjects (50.9±10.5 vs 46.6±9.4, 35.2±8.3 vs 31.8±5.4) (P<0.05). And, participants aged 25-35 year-old. got satiety score significantly higher than aged 36-45 (51.3±11.0 vs 45.6±12.1, 34.1±6.8 vs 32.5±7.9), the difference was statistically significant (P<0.05). The scores of hunger in the group of nutrition-adequate breakfast, nutrition-inadequate breakfast and no breakfast were 26.3 ± 8.0, 35.1 ± 11.2 and 57.3 ± 17.0, respectively (P<0.05). Conclusion: The nutrition quality of breakfast affects the satiety of young white-collar workers. The better the nutrition quality of breakfast is, the higher the satiety score and the lower the hunger score become. Compared with women and participants aged 36-45 year-old, men and those aged 25-35 year-old get satiety sense more easily.

[Value of single-source dual-energy CT (ssDECT) in differentiating lipid-poor adrenal adenomas from metastatic lesions].

Objective: To evaluate the value of single-source dual-energy CT (ssDECT) in differentiating lipid-poor adenomas from metastases in adrenal glands. Methods: From August 2011 to Oct 2014, 63 patients with 73 adrenal nodules (53 metastases proven by 5-6 months follow-up, and 20 histopathologically proven adenomas, CT value > 10 HU) underwent ssDECT scanning. The CT values of conventional polychromatic CT and virtual monochromatic images (40-140 keV) , fat-water density images and effective atomic number (eff-Z) were reconstructed on an ADW4.5 workstation and ROC curves were then constructed to evaluate the effectiveness of each parameter. The slope of spectral curve was measured and divided into 3 types: increment curve (K>0.1), straight curve (-0.1≤K≤0.1) and decrement curve (K< -0.1) according to the slope (the value of K) of spectral curve, and the curve patterns in the two groups were compared statistically. Results: There was no statistical difference between the mean CT values of metastases (35.12±5.29)HU and lipid-poor adenomas (32.48±6.94)HU by conventional polychromatic CT (P>0.05). The range of single-energy CT values of metastases [from (53.00±15.12) HU to (33.38±5.67) HU] was significantly higher than that of lipid-poor adenomas [from (26.90±26.94) HU to (28.77±10.66) HU] at energy levels ranging from 40 to 80 keV (P<0.05). There was no significant difference between the single-energy CT value of metastases and lipid-poor adenomas at energy levels ranging from 90 to 140 keV (P>0.05). The median fat-water concentration of metastases was -164.61 µg/cm3, significantly lower than that of lipid-poor adenomas (114.32 µg/cm3,P<0.05). The eff-Z of metastases (7.76±0.15) was also significantly higher than that of lipid-poor adenomas (7.50±0.25, P<0.05). When the threshold of fat-water concentration was -143.89 µg/cm3, the sensitivity, specificity and accuracy rate of metastasis diagnosis was 70.0%, 66.0%, and 76.7%, respectively. When the threshold of eff-Z was 7.63, the sensitivity, specificity and accuracy rate of metastasis diagnosis was 83.0%, 65.0%, and 80.4%, respectively. The lower the energy, the higher the diagnostic accuracy at energy levels ranging from 40 to 80 keV, and that of 40 keV was the highest. The spectral curves of metastases included 2 (3.8%) ascending curves, 9 (17.0%) straight curves and 42 (79.2%) descending curves, while in the 20 lipid-poor adenomas, there were 9 (45.0%) ascending curves, 4 (20.0%) straight curves and 7 (35.0%) descending curves, showing significant differences between the two groups (P<0.05). Conclusions: Single-source dual-energy CT provides an effective multi-parameter approach for differentiating lipid-poor adrenal adenomas from metastases.

[A comparison of clinical characteristics in elderly patients with ulcerative colitis and ischemic colitis].

OBJECTIVE: To analyze the discrepancy and similarities of clinical characteristics in elderly patients with ulcerative colitis (UC) and ischemic colitis (IC). METHODS: A total of 43 elderly patients (age≥60 yrs) with UC and 36 elderly patients with IC were enrolled from 2004 to 2015 at Peking Union Medical College Hospital. The clinical characteristics were retrospectively analyzed and compared between the two groups. RESULTS: Compared with IC group, the disease course was longer with lower incidence of cardiovascular comorbidities in UC patients (P<0.05). In UC group, more patients presented with diarrhea, mucopurulent bloody stool [39(90.7%) vs 16(44.4%) and 34(79.1%) vs 2(5.6%) respectively, both P<0.01]. Yet bloody stool as the only symptom was seen in more IC patients than UC patients [61.1%(22/36) vs 7.0%(3/43), P<0.01]. The ratio of extra-intestinal manifestations was higher [18.6%(8/43) vs 0(0/36)] in UC patients, while complications were lower [11.6%(5/43) vs 30.6%(11/36), P<0.05]. As to the laboratory parameters, median platelet count [(294.38±104.83)×10(9)/L vs (235.47±94.82)×10(9)/L, P<0.05] was higher in UC group. In addition, more patients with UC had positive perinuclear antineutrophil cytoplasmic antibody (p-ANCA) [50.0%(15/30) vs 10.0%(2/20), P<0.05]. The most commonly involved regions of IC were descending colon and sigmoid colon, in which the lesions were clearly demarcated with the normal mucosa. Lesions in patients with UC mainly originated from rectum and might spread to the whole colon. Vascular occlusion and micro thrombosis were characteristic pathological findings of IC. The crypt abscesses were frequently seen in the UC group. CONCLUSION: Even though UC and IC have some similar manifestations in the elderly patients, clinical and pathological discrepancy is still helpful to differentiate each other.

[Value of R2(*) in evaluating the biological behavior of primary hepatocellular carcinoma].

OBJECTIVE: To investigate the correlation between R2(*) value of enhanced T2 star-weighted angiography (ESWAN) sequence and primary hepatocellular carcinoma infiltration and tumor thrombus, and investigate the biological behavior of HCC. METHODS: A total of 221 cases of patients' imaging data with MRI examination(including ESWAN sequence) diagnosed as primary HCC were retrospectively analyzed.All the patients were collected from January 2014 to September 2015 in the First Affiliated Hospital of Dalian Medical University.The differences of R2(*) values in different MR types of HCC were analyzed.All patients were divided into infiltration group and non-infiltration group, tumor thrombus group and non-tumor thrombus group, the R2(*) values of the paired groups were compared.The diagnostic efficiency of R2(*) in HCC infiltration and tumor thrombus were evaluated by ROC curve, and to find out the threshold values. RESULTS: The MR types of 221 patients included 90 cases of nodular type, 62 cases of massive type, 69 cases of diffuse type.70 patients had tumor thrombus.The R2(*) values of different MR types were (21.82±8.52), (24.17±8.84)and (34.45±11.73) Hz, respectively.There was no statistically significant difference between the nodular and the massive types (P=0.144), while the difference between the nodular and diffuse type, the massive and diffuse types were statistically significant(P=0.000). The R2(*) values of infiltration group and non-infiltration group were (34.45±11.73) and (22.78±8.70) Hz , the R2(*) values of tumor thrombus group and non-tumor thrombus group were (31.20±12.17) and (24.21±9.90) Hz, the difference also had statistically significant(t=7.397 and 4.534, P=0.000 and 0.000). The AUC of R2(*) values for infiltration and tumor thrombus were 0.804, 0.681. R2(*) ≥24.68 Hz was the threshold value to diagnose the infiltration and tumor thrombus. CONCLUSION: R2(*) value can be used as a MR non-enhancement quantitative index to evaluate the biological behavior of HCC.

IKK-ß mediates hydrogen peroxide induced cell death through p85 S6K1.

The IκB kinase (IKK)/NF-κB pathway has been shown to be a major regulator in cell survival. However, the mechanisms through which IKK mediates cell death are not clear. In this study, we showed that IKK-ß contributed to hydrogen peroxide (H(2)O(2))-induced cell death independent of the NF-κB pathway. Our results demonstrated that the pro-death function of IKK-ß under oxidative stress was mediated by p85 S6K1 (S6 kinase 1), but not p70 S6K1 through a rapamycin-insensitive and mammalian target of rapamycin complex 1 kinase-independent mechanism. We found that IKK-ß associated with p85, but not p70 S6K1, which was required for H(2)O(2)-induced activation of p85 S6K1. IKK-ß and p85 S6K1 contributed to H(2)O(2)-induced phosphorylation of Mdm2 (S166) and p53 accumulation. p85 S6K1 is critical for IKK-ß-mediated cell death. Thus, these findings established a novel oxidative stress-responsive pathway that involves IKK-ß, p85 S6K1 and Mdm2, which is response for H(2)O(2)-induced cell death. Our results have important implications for IKK-ß and p85 S6K1 as potential targets for the prevention of diseases involved in oxidative stress-induced aberrant cell death.

Critical role of arachidonic acid-activated mTOR signaling in breast carcinogenesis and angiogenesis.

The mammalian target of rapamycin (mTOR) signaling pathway is upregulated in the pathogenesis of many cancers. Arachidonic acid (AA) and its metabolites play critical role in the development of breast cancer, but the mechanisms through which AA promotes mammary tumorigenesis and progression are poorly understood. We found that the levels of AA and cytosolic phospholipase A2 (cPLA2) strongly correlated with the signaling activity of mTORC1 and mTORC2 as well as the expression levels of vascular epithelial growth factor (VEGF) in human breast tumor tissues. In cultured breast cancer cells, AA effectively activated both mTOR complex 1 (mTORC1) and mTORC2. Interestingly, AA-stimulated mTORC1 activation was independent of amino acids, phosphatidylinositol 3-kinase (PI3-K) and tuberous sclerosis complex 2 (TSC2), which suggests a novel mechanism for mTORC1 activation. Further studies revealed that AA stimulated mTORC1 activity through destabilization of mTOR-raptor association in ras homolog enriched in brain (Rheb)-dependent mechanism. Moreover, we showed that AA-stimulated cell proliferation and angiogenesis required mTOR activity and that the effect of AA was mediated by lipoxygenase (LOX) but not cyclooxygenase-2 (COX-2). In animal models, AA-enhanced incidences of rat mammary tumorigenesis, tumor weights and angiogenesis were inhibited by rapamycin. Our findings suggest that AA is an effective intracellular stimulus of mTOR and that AA-activated mTOR plays critical roles in angiogenesis and tumorigenesis of breast cancer.

Factors influencing the mode of delivery and associated pregnancy outcomes for twins: a retrospective cohort study in a public hospital.

OBJECTIVES: To determine current trends for different modes of delivery in twin pregnancies, factors affecting the mode of delivery, and associated outcomes. DESIGN: Retrospective cohort study. SETTING: A public hospital in Hong Kong. PARTICIPANTS: All twin pregnancies booked at Kwong Wah Hospital during a 3-year period from 1 April 2006 to 31 March 2009. RESULTS: Of 197 sets of twins, 35 (18%) were delivered vaginally and 162 (82%) by caesarean section (47% were emergencies and 53% elective). In all, 32 (37%) of the elective and 21 (28%) of the emergency caesarean sections were in response to maternal requests. Vaginal delivery was more common in mothers with a history of vaginal delivery and monochorionic diamniotic twins. Women who conceived by assisted reproduction or those who had a tertiary education were more likely to deliver by caesarean section. The type of conception and the presentation of the second twin were statistically significant factors affecting maternal choice on the mode of delivery. Maternal age did not affect the choice of delivery mode. Except for the higher frequency of sepsis and cord blood acidosis in second twins delivered vaginally, there were no significant differences in neonatal morbidity between the groups that attempted vaginal delivery or requested caesarean sections. All the women who had compression sutures or hysterectomy to control massive postpartum haemorrhage were delivered by caesarean section. CONCLUSION: A high caesarean section rate observed in our cohort was associated with maternal requests for this mode of delivery. The type of conception and the presentation of the second twin were statistically significant factors affecting maternal choice on mode of delivery. Women's requests for caesarean delivery out of the concern for their babies are not supported by current evidence. In response to a woman with a twin pregnancy requesting caesarean delivery, the pros and cons of vaginal deliveries and caesarean sections should be fully explained before the woman's autonomy is respected.

Poly(dimethylsiloxane) microchip capillary electrophoresis with electrochemical detection for rapid measurement of acetaminophen and its hydrolysate.

Poly(dimethylsiloxane) microchip capillary electrophoresis with amperometric detection has been used for rapid separation and determination of acetaminophen and its hydrolysate, i.e. p-aminophenol. A Pt ultramicroelectrode with a diameter of 10 microm positioned at the outlet of the separation channel was used as a working electrode for amperometric detection. Factors influencing separation and detection were investigated and optimized. Results show that acetaminophen and p-aminophenol can be well separated within 35 s with RSD-1 (approximately 0.1 fmol) at S/ N=3. This method has been successfully applied to the detection of traces of p-aminophenol in paracetamol tablets.

Effects of glucagon on in vitro liquid production by lungs from fetal guinea pigs.

BACKGROUND: Lung liquid reabsorption in newborns with respiratory distress syndrome can be deficient. Respiratory distress syndrome is often seen in infants of diabetic mothers, in whom the neonatal surge of glucagon is suppressed. AIM: To investigate the possible effects of glucagon on lung liquid reabsorption. METHODS: Lungs from near term fetal guinea pigs (62 (2) days gestation; term = 67 days) were supported in vitro for three hours; lung liquid production and reabsorption were monitored by a dye dilution method. RESULTS: Untreated control preparations produced fluid at 1.75 (0.33) ml/h per kg body weight, and did not change significantly in three hours; those immersed in 10(-12) M glucagon during the middle hour showed no significant change, but those given higher concentrations all showed significant reductions in fluid production or even reabsorption (65.6 (10.3)% fall at 10(-11) M, 70.0 (6.3)% fall at 10(-10) M, and 90.6 (11.1)% fall at 10(-9) M; based on 54 preparations). At 10(-9) M glucagon, 12 out of 30 preparations reabsorbed fluid. The linear log dose-response curve (r(2) = 0.94) gave a theoretical threshold at 4 x 10(-15) M glucagon. Responses appeared to involve the amiloride sensitive Na(+) based reabsorptive system: responses to 10(-9) M glucagon appeared to be reduced by 10(-6) M amiloride, and were abolished by 10(-5) M amiloride (based on 72 preparations). CONCLUSIONS: The results suggest that the surge of glucagon at birth may help to drain the lungs of fluid. As glucagon liberates cAMP, which also stimulates surfactant, glucagon is worth consideration for possible use in neonatal respiratory distress.

Effects of acetylcholine on lung liquid production by in vitro lungs from fetal guinea pigs.

Lungs from near-term fetal guinea pigs (61 +/- 2 days of gestation) were supported in vitro for 3 h; lung liquid production was monitored by a dye dilution method. Untreated preparations produced lung liquid with no significant changes (ANOVA; regression analysis) (rates in successive hours, initial study: 1.37 +/- 0.30, 1.36 +/- 0.30, and 1.28 +/- 0.27 mL.kg-1 body weight.h-1; n = 6). Preparations given acetylcholine at 10(-4) (n = 6), 10(-5) (n = 6), and 10(-6) M (n = 18) during the middle hour showed marked and significant fluid reabsorption (p < 0.025-0.0005); 10(-8) M acetylcholine was without effect. Reductions were linearly related to log concentration of acetylcholine (r = 0.97; theoretical threshold, 1.0 x 10(-7) M acetylcholine). Atropine, at 10(-5) M, greatly reduced responses to acetylcholine, and all reabsorptions were abolished; 10(-4) M atropine completely abolished all responses to acetylcholine; atropine alone had no effect (based on 48 studies). The alpha-adrenoreceptor antagonist phentolamine (1.78 x 10(-5) M) abolished the effects of 10(-6) M acetylcholine, but had no effect alone (based on 48 studies); the beta-adrenoreceptor antagonist propranolol (10(-5) M) had no effect on responses to 10(-6) M acetylcholine (based on 24 studies). It is suggested that acetylcholine at physiological levels can produce lung liquid reabsorption by activating muscarinic receptors and releasing catecholamines within the lungs; these catecholamines act via alpha-receptors. This raises the possibility of neural controls of lung liquid reabsorption during the early stages of delivery or neonatal life.

Regeneration following somite removal in chick embryos.

A technique was developed for ensuring complete removal of single somites with minimal damage to surrounding tissues in 2-day-old chick embryos. Histological examination of the site of somite removal at various time intervals after operation revealed that a regeneration mechanism could be triggered. Replacement of the cells that had been removed could occur, but the extent of the replacement was dependent on the immediate fate of the gap created. If the gap was closed by enlargement of the adjacent somites, no replacement of the cells occurred. If the gap remained, then cells invaded the gap and were able to produce a normal sclerotome and dermomyotome. By labelling adjacent cells with the carbocyanine dye. DiI, it was shown that the replacement cells could come from the adjacent somites, as well as the intermediate mesoderm. Use of an antibody to HNK-1 established that the replacement cells did not come from the neural crest and that the neural crest cell distribution was little affected. Staining with peanut agglutinin showed that the replacement cells were able to adopt the characteristics associated with rostral and caudal halves of the normal sclerotome. These results provide possible explanations for the variety of vertebral anomalies produced by removal of somites and for the production of some congenital vertebral anomalies.

Inhibition of ciramadol glucuronidation by benzodiazepines.

Studies on the inhibition of ciramadol glucuronidation by benzodiazepines were performed in vitro and in vivo. Ciramadol glucuronidation was slower (Vmax, 1.56 vs. 5.40 nmol/min/mg of microsomal protein) in human than in dog liver microsomes. Inhibition constants (Ki) for lorazepam and oxazepam were 3 to 4 times higher than that calculated for diazepam. Rates of morphine glucuronidation in human liver microsomes were assessed for comparative purposes and agreed with literature values. Each benzodiazepine appeared to be a competitive inhibitor of ciramadol and morphine UDP-glucuronyltransferase activity. The in vivo disposition of ciramadol was unchanged in dogs pretreated with lorazepam. After diazepam treatment no change in the Vdss of ciramadol occurred, but plasma clearance was significantly reduced, resulting in a prolongation of t1/2. Diazepam caused a significant reduction in the oral clearance of ciramadol, whereas no change occurred in systemic availability. Thus, diazepam may have had a secondary effect on hepatic blood flow (QH) and produced offsetting alterations in both intrinsic clearance (Cl int) and QH. A decrease in the area under the plasma concentration time curves of ciramadol aryl O-glucuronide following iv treatment with diazepam coupled with the in vitro data indicate that the mechanism for the decrease in the clearance of ciramadol is inhibition of its glucuronidation by diazepam. Since glucuronidation plays a major role in the elimination of ciramadol in man and dog, these experiments suggest that the disposition of ciramadol in man would not be affected by coadministration of lorazepam, whereas the potential for a diazepam/ciramadol drug interaction in humans exists.

The metabolic disposition of 14C-ciramadol in humans.

Twelve subjects received single 15 mg oral doses of 14C-ciramadol. Excretion of the dose occurred almost entirely by the renal route (93.5 +/- 11.7 (S.D.)% of the dose), and only 0.7 +/- 0.6% of the dose was recovered in faeces indicating that absorption was essentially complete. More than 90% of the amount recovered in urine was excreted within 24 h after dosing. Unchanged drug accounted for 43.9 +/- 6.5% of the dose, while a phenolic glucuronide conjugate was the only major urinary metabolite accounting for a further 37.9 +/- 7.8%. A second glucuronide that was conjugated with the alicyclic ring was also identified but constituted only 2.3 +/- 0.6% of the dose. Concentrations of radioactivity in plasma reached a peak at 2 h after dosing and declined with a terminal disposition half life of 4.9 h. Only ciramadol and the aryl-O-glucuronide were detected in substantial amounts in plasma. Renal clearance of ciramadol amounted to 298 +/- 54 ml/min suggesting tubular secretion in addition to glomerular filtration.

Determination of ciramadol in plasma by gas-liquid chromatography.

An analytical method for determining ciramadol concentrations in plasma was developed and evaluated for its specificity, precision, linearity, and sensitivity. GLC-electron capture detection of a dipentafluorobenzoyl derivative of the drug was used for quantitation. An isomer of the drug served as an internal standard. Resulting mean ratios of the peak height of derivatized drug to that of derivatized internal standard varied with a coefficient of variation that ranged from 3.8 to 11.1%. The mean ratio was linearly related to ciramadol content (8.75-175 ng) with a correlation coefficient greater than to 0.999. The minimum quantifiable concentration was 4 ng/ml with a 2-ml specimen. An application of this method is presented.