An in-vitro study on the metabolism of rokitamycin and possible interactions of the drug with rat liver microsomes

This in-vitro study was designed to identify the enzyme(s) involved in the major metabolic pathway of rokitamycin, i.e. the formation of leucomycin A7, and to assess possible interactions of the drug with rat liver microsomes. Formation of leucomycin A7 was NADPH-independent and was not appreciably inhibited by anti-rat NADPH cytochrome P-450 reductase serum or cimetidine, a nonspecific inhibitor of cytochrome P-450 isoforms. Eadie-Hofstee plots for the formation of leucomycin A7 were indicative of apparently monophasic behaviour for six rat liver microsomes tested. The mean (+/- s.d.) kinetic parameters, Km, Vmax and Vmax/Km, for the formation of leucomycin A7 from rokitamycin were 47+/-13 microM, 390+/-56 nmol min(-1) (mg protein)(-1) and 8.6+/-1.6 mL min(-1) (mg protein)(-1), respectively. Three esterase inhibitors (100 microM), bis-nitrophenylphosphate, physostigmine and metrifonate inhibited the formation of leucomycin A7 by more than 60%. Metabolism of rokitamycin was inhibited by terfenadine, but not by mequitazine, whereas chlorpheniramine and theophylline activated the formation of leucomycin A7. Rokitamycin, leucomycin A7, leucomycin V, erythromycin and clarithromycin were weak inhibitors of CYP3A-catalysed 3-hydroxylation of quinine with mean IC50 values ranging from 71 to >100 microM. It is concluded that in rat liver microsomes the formation of leucomycin A7 from rokitamycin is catalysed mainly by an esterase (possibly cholinesterase, EC3.1.1.8), but not by cytochrome P-450 enzyme(s). Although in this in-vitro animal study CYP3A activity was barely inhibited by rokitamycin, the possibility cannot be totally discounted in man when rokitamycin is co-administered with drugs metabolized by CYP3A.

From single atoms to self-assembled quantum single-atomic nanowires: noble metal atoms on black phosphorene monolayers

Transition metal (TM) nanostructures, such as one dimensional (1D) nanowires with/without substrates, usually possess drastically different properties from their bulk counterparts, due to their distinct stacking and electronic confinement. Correspondingly, it is of great importance to establish the dominant driving force in forming 1D single-metal-atom-wires (SMAWs). Here, with first-principles calculations, taking the black phosphorene (BP) monolayer as a prototype 2D substrate, we investigate the energetic and kinetic properties of all the 5d-TM atoms on the 2D substrate to reveal the mechanism of formation of SMAWs. In contrast to other 5d- and 4d-TMs, noble metal elements Pd and Pt are found to prefer to grow along the trough in an atom-by-atom manner, self-assembling into SMAWs with a significant magic growth behavior. This is due to distinct binding energies and diffusion barriers along the trough, i.e., zig-zag direction, as compared to other directions of the BP. The present findings are valuable in the fabrication and modulation of 1D nanostructures which can be anticipated to possess desirable functionalities for potential applications such as in nanocatalysis, nanosensors, and related areas.

Dataset on assessment of magnesium isoglycyrrhizinate injection for dairy diet and body weight in fructose-induced metabolic syndrome of rats

The data presented herein are related to the research article entitled “Magnesium isoglycyrrhizinate blocks fructose-induced hepatic NF-κB/NLRP3 inflammasome activation and lipid metabolism disorder” (Zhao et al., 2017) [1]. This article describes the effects of magnesium isoglycyrrhizinate on 24-h food or water intake in fructose-fed rats at 15-week. In addition, this article expands the effect of magnesium isoglycyrrhizinate on the animal body weight change during 1–17 week. The field dataset is made publicly available to enable critical or extended analyzes.

[Clinical analysis of 7 cases with anti-Caspr2 antibody-associated autoimmune encephalitis]

Objective: To investigate the clinical features, laboratory tests, imaging features, electroencephalogram (EEG) manifestations, treatment and prognosis of anti-CASPR2 antibody-associated autoimmune encephalitis with the purpose to improve the understanding of the disease. Methods: Seven patients diagnosed with CASPR2 antibody-associated encephalitis in the Fifth and first Affiliated Hospital of Zhengzhou University from January 2017 to January 2019 were selected. The clinical manifestations, course of disease, imaging, treatment plan and prognosis of the patients were retrospectively analyzed. Results: Of the 7 patients, 4 were male and 3 were female. The median age of onset was 34 years old (range, 11-66 years). Seizures (6/7), memory decline(5/7), and neuropsychiatric disorders (4/7) were common clinical manifestations. CASPR2 antibody was detected in the CSF of 3 patients (3/7) and the serum of all patients (7/7). Notable imaging changes were observed in 5 patients (5/7). All patients received immunotherapy and were followed up for 1 month to 2 years. One patient was diagnosed with rectal cancer with a poor prognosis; all the others got a good prognosis. Conclusions: CASPR2 antibody-related encephalitis is a rare autoimmune disease. It is considered to present with seizures, memory loss, psychiatric symptoms, dizziness and sleep disorders as the main clinical manifestations. Early identification and treatment of the disease can help the patients achieve a good prognosis.

[Analysis of the efficacy and safety of coblation and pulsed radiofrequency in the treatment of cervicogenic headache]

Objective: To explore the efficacy and safety of coblation and pulsed radiofrequency on cervicogenic headache (CEH). Methods: A total of 118 patients with CEH who underwent coblation or pulsed radiofrequency in the Department of Pain Management at Xuanwu Hospital, Capital Medical University from August 2018 to June 2020 was retrospectively collected. Patients were divided into the coblation group (n=64) and the pulsed radiofrequency group (n=54) according to different surgical methods. In the coblation group, there were 14 males and 50 females, aged 29-65 (49.8±10.2) years, while in the pulse radiofrequency group, there were 24 males and 30 females, aged 18-65 (41.7±14.8) years. Visual analogue scale (VAS) score, postoperative numbness in the affected areas and other complications were recorded and compared between the two groups at preoperative 3 d, and 1 month, 3 months and 6 months postoperatively. Results: The VAS score of the coblation group was (7.16±0.91), (3.67±1.13), (1.59±0.91), (1.66±0.84) and (1.56±0.90) before operation, and 3 days, 1 month, 3 months and 6 months after surgery. Likewise, the VAS score of the pulsed radiofrequency group was (7.01±0.78), (1.58±0.88), (1.57±0.94), (3.71±1.08) and (6.92±0.83) at the aforementioned time points. There were statistically significant differences of VAS scores between the coblation group and the pulsed radiofrequency group at 3 days, 3 months and 6 months postoperatively (all P<0.001). Intra-group comparison revealed that VAS scores in the coblation group were significantly lower than those before surgery at all time points after surgery (all P<0.001), while VAS scores in the pulsed radiofrequency group were significantly decreased at 3 days, 1 month and 3 months after surgery (P<0.001). The incidence of numbness was 72% (46/64), 61% (39/64), 6% (4/64) and 3% (2/62) in the coblation group and 7% (4/54), 7% (4/54), 2% (1/54) and 0 (0/54) in the pulsed radiofrequency group, respectively. At 3 days and 1 month after surgery, the incidence of numbness in the coblation group was higher than those in the pulsed radiofrequency group (both P<0.001). In the coblation group, one patient developed pharyngeal discomfort 3 days after surgery, which disappeared spontaneously 1 week after surgery without special treatment. One patient developed vertigo after getting up in the morning at 3 days postoperatively, and the possibility of transient cerebral ischemia was considered. In the pulsed radiofrequency group, one patient developed nausea and vomiting after operation, but spontaneous remission was observed after one hour without special treatment. Conclusions: Both coblation and pulsed radiofrequency are effective and safe in the treatment of CEH. But the VAS scores at 3 and 6 months after coblation is significantly lower than those of pulsed radiofrequency ablation group, and the efficacy is better in those undergoing coblation.

Relative edge energy in the stability of transition metal nanoclusters of different motifs

When a structure is reduced to a nanometer scale, the proportion of the edge atoms increases significantly, which can play a crucial role in determining both their geometric and electronic properties, as demonstrated by the recently established generalized Wulff construction principle [S. F. Li, et al., Phys. Rev. Lett., 2013, 111, 115501]. Consequently, it is of great interest to clarify quantitatively the role of the edge atoms that dominate the motifs of these nanostructures. In principle, establishing an effective method valid for determining the absolute value of the surface energy and particularly the edge energy for a given nanostructure is expected to resolve such a problem. However, hitherto, it is difficult to obtain the absolute edge energy of transition metal clusters, particularly when their sizes approach the nanometer regime. In this paper, taking Ru nanoclusters as a prototypical example, our first-principles calculations introduce the concept of relative edge energy (REE), reflecting the net edge atom effect over the surface (facet) atom effect, which is fairly powerful to quasi-quantitatively estimate the critical size at which the crossover occurs between different configurations of a given motif, such as from an icosahedron to an fcc nanocrystal. By contrast, the bulk effect should be re-considered to rationalize the power of the REE in predicting the relative stability of larger nanostructures between different motifs, such as fcc-like and hcp-like nanocrystals.

[Characteristics of contrast-enhanced ultrasound in alpha-fetoprotein-negative recurrent small hepatocellular carcinoma]

Objective: To investigate the characteristics of contrast-enhanced ultrasound (CEUS) in alpha-fetoprotein (AFP)-negative recurrent small hepatocellular carcinoma (rsHCC). Methods: The imaging characteristics of CEUS were retrospectively analyzed in 132 lesions from 116 patients with rsHCC, including 59 lesions from 51 AFP-negative patients and 73 lesions from 65 AFP-positive patients. The hemodynamic parameters such as contrast-enhanced onset time, time-to-peak, isoenhancement start time, low-enhancement start time, and perfusion mode were compared between two groups. Results: The time-to-peak, isoenhancement start time, low-enhancement start time of AFP-negative group were significantly increased than those in AFP-positive group (23.22±5.08)s vs. (20.30±3.41)s, (59.44±39.75)s vs. (40.75±16.16)s, (102.89±44.45)s vs. (87.08±25.27)s (all of P<0.05). Meanwhile, the proportion of isoenhancement during the portal and late phases in AFP-negative group was significantly higher than those in AFP-positive group (59.3% vs. 37.0%, 16.9% vs. 4.1%; all of P<0.05). However, there was no significant difference between the two groups in the enhancement start time (14.87±6.00)s vs. (14.35±5.30)s (P>0.05) as well as isoenhancement proportion in the arterial phase (94.9% vs. 98.6%, P>0.05). Conclusions: The enhancement pattern of CEUS in AFP-negative rsHCC patients was "fast-in and slow-out" with a diverse and atypical trend. Recognizing its regular features will facilitate the early detection of AFP-negative rsHCC.

[Correlation of serum lipid profile and disease activity in patients with inflammatory bowel disease]

To analyze the correlation between lipid profile and disease activity in patients with inflammatory bowel disease (IBD).A total of 307 Crohn's disease (CD) patients, 232 ulcerative colitis (UC) patients and 165 healthy subjects from the same geographic region were included. Total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and lipoprotein(a)[Lp(a)] were retrieved from their medical records. Crohn disease activity index (CDAI) and Mayo scores were calculated as measurement of disease severity for CD and UC separately. Patients with CD and UC had lower TC, TG, HDL-C and LDL-C levels than those in control group (P<0.05). Additionally, CDAI was negatively associated with TC, HDL-C and LDL-C levels (r=-0.218, -0.210, -0.176, P<0.05), while TG level was not associated with CDAI. Mayo scores was not significantly associated with TC, HDL-C, LDL-C and TG. Patients with CD had higher Lp(a) levels than those in UC and control group (P<0.05). Furthermore, patients with active CD had higher Lp (a) levels than those with inactive disease (P<0.05).The Lp(a) levels in CD patients were positively associated with CDAI (r=0.151, P<0.05), while Lp(a) level in UC group was nor assocriated with Mayo score. Patients with IBD have dyslipidemia and lipid profile is associated with disease activity in CD patients.

Purification of beta-lactamases and enzyme kinetic studies on aztreonam

Standard beta-lactamases K1, P99, TEM-1, SHV-1 and beta-lactamase K-CAZ purified using FPLC through ion-exchange chromatography and filtration chromatography, were identified by determination of isoelectric points, molecular weights and substrate profiles. The results showed that the beta-lactamase stability of domestic aztreonam was very similar to that of cefotaxime, ceftazidime and much better than that of cefoperazone. Aztreonam showed a high affinity to chromosomal-mediated cephalosporinase P99, its Ki for inhibition of P99 with cephaloridine as substrate was 0.0159 microns. Aztreonam and the three third generation cephalosporins tested were not stable to beta-lactamase K-CAZ, which hydrolysed them in different degrees.

A study on the metabolism of etoposide and possible interactions with antitumor or supporting agents by human liver microsomes

The metabolism of etoposide was investigated by using human liver microsomes and nine recombinant human cytochrome P450 (CYP) isoforms to identify the CYP isoform(s) involved in the major metabolic pathway (3'-demethylation) of etoposide as well as to evaluate the possible metabolic interactions with several antitumor or supporting agents. The 3'-demethylation of etoposide followed a Michaelis-Menten one-enzyme kinetic behavior in six human liver microsomal samples. The relationships were assessed with six different human liver microsomes between the 3'-demethylation of etoposide and metabolic activities for substrate probes of the respective CYP isoforms, showing a significant correlation (r = 0. 932, P < .01) only with 6beta-hydroxylation of testosterone, a marker substrate for CYP3A4. Inhibitor/substrate probes for CYP3A4, ketoconazole, troleandomycin, verapamil and cyclosporin, or supporting agents, vincristine and prednisolone, inhibited etoposide 3'-demethylation by human liver microsomes. p-Nitrophenol, a substrate for CYP2E1, also inhibited etoposide 3'-demethylation. Among the nine recombinant human CYP isoforms, CYP3A4 exhibited the highest catalytic activity with respect to etoposide 3'-demethylation, compared with the minor activities of CYP1A2 and 2E1. Collectively, these data suggest that etoposide 3'-demethylation is mediated mainly by CYP3A4 and to a minor extent by CYP1A2 and 2E1. Furthermore, some supporting agents (vincristine and prednisolone) and the substrates of CYP3A4, which may be coadministered with etoposide during the cancer chemotherapies, inhibit the etoposide 3'-demethylation activity in vitro. The results may provide clinical implications with respect to the possible metabolic interactions between etoposide and other drugs studied herein in patients with cancer undergoing etoposide concurrently with either of them.

[Acquired von Willebrand syndrome in three patients and literature review]

OBJECTIVE

To deepen the understanding of acquired von Willebrand syndrome (AVWS).

METHODS

The clinical data of 3 patients were analyzed and related literature were reviewed.

RESULTS

① Case 1, a 70- year- old male, diagnosed as Waldenstrom macroglobulinemia and AVWS, was presented with spontaneous epitaxis and bruising. The VWF∶Ag level was 16%. Treatment was initiated with VWF concentrates. Two cycles of chemotherapy with Bortezomib, thalidomide and Dexamethasone were followed. Partial remission was achieved. Half- year' follow- up showed no sign of spontaneous hemorrhage. ② Case 2, a 48- year- old female, diagnosed as monoclonal gammopathy of undetermined significance and AVWS, was presented with repeated epitaxis. The VWF∶Ag level was 7%. Because the bleeding was slight and self-relieved, no specific treatment was addressed. She was followed up for one and a half year. ③ Case 3, a 50- year- old man, diagnosed as monoclonal gammopathy of undetermined significance and AVWS, was referred to our hospital for presentation with significant hematomas. VWF∶ Ag was reduced to 12%. VWF- containing cryoprecipitate, plasma, intravenous immunoglobulin and rituximab were used to control his bleeding symptom. During the follow-up, spontaneous hemorrhage still occurred occasionally.

CONCLUSIONS

Acquired von Willebrand syndrome presented with heterogeneous symptoms. The level of VWF∶Ag and VWF∶Rco for patients with bleeding disorder should be performed. Abnormal bleeding symptoms in elderly patients without personal or family history of bleeding should prompt consideration of the underlying disorders. Treatment included controlling acute bleeding, curing the underlying diseases and preventing bleeding in high- risk situations. The prognosis of acquired von Willebrand syndrome is mainly related to the underlying diseases.

[Expression and function of non-muscle myosin-IIA in Fechtner syndrome]

The study was purposed to investigate the expression and function of non-muscle myosin heavy chain-IIA (NMMHC-IIA) in Fechtner syndrome in order to explore the pathologic changes of kindy disease and the mechanism of granulocyte inclusion body formation. NMMHC-IIA levels in granulocytes were analyzed by Western-blot, the expressions of NMMHC-IIA, IIB in HEK-293 cells were detected by RT-PCR and were analyzed by co-immunoprecipitation. The results indicated that the IIA/beta-actin ratio for Fechtner syndrome granulocytes was (0.35 +/- 0.12), and obviously decreased as compared with that of normal control (0.87 +/- 0.18) (p < 0.01). The IIA and IIB expressed higher in HEK-293 cells. The interaction of IIA and IIB was confirmed by co-immunoprecipitation in HEK-293 cells. It is concluded that dominant-negative effect of NMMHC-IIA is involved in the formation of inclusion bodies. IIA and IIB show obvious interaction, IIB partly compensates the IIA defect derived from MYH9 mutations, and may delay or prevent the development of clinically relevant abnormalities.

[Clinical study on transcutaneous electrical acupoint stimulation combined with skin sympathetic response to evaluate autonomic nerve preservation after laparoscopic radical gastrectomy]

Objective: This study aimed to explore the utility of transcutaneous electrical acupoint stimulation (TEAS) combined with skin sympathetic response (SSR) in assessing the effectiveness of perigastric autonomic nerve preservation during radical gastrectomy. Methods: A retrospective cohort analysis was conducted involving 221 patients who underwent laparoscopic radical gastrectomy at the Department of Gastric Surgery, Taizhou People's Hospital, affiliated with Nanjing Medical University, between June 2022 and September 2024. The cohort comprised 109 patients who underwent laparoscopic radical total gastrectomy without autonomic nerve preservation (total gastrectomy without nerve preservation group). Additionally, 112 patients underwent laparoscopic radical distal gastrectomy, including 34 patients who received autonomic nerve preservation (nerve preservation group) and 78 patients who did not (without nerve preservation group). TEAS was administered at the Zusanli and Tianshu acupoints one day before and one day after surgery, during which SSR latency and voltage amplitudes in the upper and lower extremities were recorded and compared across groups. Differences in SSR latency and voltage amplitude between the nerve preservation and non-nerve preservation groups of the distal gastrectomy cohort were also analyzed. Further, TEAS was applied at the same acupoints for 15 minutes on the 1st, 2nd, and 3rd postoperative days, and changes in intestinal sounds and intestinal functional recovery time were monitored. Surgical parameters, including operative duration, intraoperative blood loss, and harvested lymph node, were documented. Postoperative inflammatory indicators, including interleukin-6 (IL-6), C-reactive protein (CRP), procalcitonin (PCT), and the incidence of anastomotic leakage, were evaluated. At three months postoperatively, gastroscopy was performed to assess residual gastric food and bile reflux. Additionally, the prognostic nutritional index (PNI) was evaluated across all patient groups. Results: Following total gastrectomy, TEAS of Zusanli combined with arms' SSR revealed a latency of (23 59.71±410.55) ms and a voltage amplitude of (0.43±1.67) mV; for the legs, latency was (2 596.88±369.01) ms and voltage amplitude was (0.25±0.08) mV. TEAS of Tianshu combined with arms' SSR demonstrated a latency of (2 746.47±224.37) ms and a voltage amplitude of (0.31±0.14) mV; for the legs, latency was (2 891.90±193.61) ms and voltage amplitude was (0.19±0.72) mV. Postoperative latency was significantly prolonged, and voltage amplitude was markedly reduced (all P < 0.01). In the distal gastrectomy with nerve preservation group, TEAS of Zusanli combined with arms' SSR showed a latency of (1 668.04±261.91) ms and a voltage amplitude of (0.78±0.26) mV; for the legs, latency was (1 568.86±220.09) ms and voltage amplitude was (0.61±0.24) mV. TEAS of Tianshu combined with arms' SSR demonstrated a latency of (1 519.36±206.99) ms and a voltage amplitude of (0.66±0.34) mV; for the legs, latency was (2 004.80±508.53) ms and voltage amplitude was (0.55±0.28) mV. In the distal gastrectomy without nerve preservation group, TEAS of Zusanli combined with arms' SSR revealed a latency of (2 385.95±710.27) ms and a voltage amplitude of (0.23±0.11) mV; for the legs, latency was (2 506.81±779.37) ms and voltage amplitude was (0.26±1.29) mV. TEAS of Tianshu combined with arms' SSR indicated a latency of (2 697.78±385.55) ms and a voltage amplitude of (0.21±0.14) mV; for the legs, latency was (2 949.14±506.61) ms and voltage amplitude was (0.17±0.11) mV. The group without nerve preservation exhibited significantly prolonged latencies and reduced voltage amplitudes (all P<0.01). No statistically significant differences were observed between the groups in operative time, intraoperative bleeding, the number of dissected lymph nodes, inflammatory indicators (IL-6, CRP, PCT) at 3 days postoperatively, or anastomotic leakage rates (all P>0.05). In the group without nerve preservation, bowel sounds on postoperative days 1, 2, and 3 were (0.36±0.58), (1.04±0.97), and (1.74±1.10) times/min, respectively, with bowel function recovery time of (62.24±9.91) hours. The PNI at 3 months postoperatively was (37.42±3.01). Incidences of food residue in the residual stomach and bile reflux were 21.79% (17/78) and 29.49% (23/78), respectively. In the group with nerve preservation, bowel sounds on postoperative days 1, 2, and 3 were (0.76±0.82), (2.03±1.34), and (3.71±1.27) times/min, respectively, with bowel function recovery time of (44.94±8.05) hours. The PNI at 3 months postoperatively was (41.34±3.40). Incidences of food residue and bile reflux were 5.88% (2/34) and 11.76% (4/34), respectively. Statistically significant differences were observed between the groups (all P < 0.05). Conclusion: TEAS of Zusanli and Tianshu combined with SSR provides an objective measure for assessing the preservation of perigastric autonomic nerves during radical gastrectomy.

[Heart morphologic state in retired fighter pilots]

Objective. To study the heart morphology in the retired fighter pilots, and to provide clinical evidence for protection combined G-loads (+ Gz), heat, noise, hypoxic and vibration stress induced cardiac structural damage. Method. Parameters of heart morphology were studied using Doppler echocardiography in 40 retired fighter pilots with 40 veteran cadres as control. Result. LVDd, LVDs, LADs, LVEDV, LVPWs and LVM in pilot group were somewhat higher than those in control group (NS); while IVSs and LVMI in pilot group were slightly lower than those in control group (NS); LVESV, aortic valve area, internal diameter of the ring and sinus in pilot group were significantly higher than those in control group (P < 0.05). Conclusion. Analysis of the results revealed no pathomorphologic damage of the heart. It suggest that all the variations can be regarded as adaptive changes due to the effects of the combined environmental factors experienced in long time flying.

[Development of a gas chromatographic column system for the on-line analysis of trace tetrahydrofuran in hexane]

A gas chromatographic system using home-made 7 microns thick cross-linked dimethylpolysiloxane columns for the on-line analysis of trace tetrahydrofuran in hexane in a rubber production facility was developed. The experimental parameters of the column system, including the temperature, flow rate as well as the back-flushing and heart-cutting program were investigated. The total column-switching program was suggested. The system has been successfully operated for more than one year with good resolution, stability and precision (RSD < 5%) in analyzing trace tetrahydrofuran (0-250 x 10(-6), V/V) for industrial process control in the rubber production facility.

Characterization of sites occupied by the anesthetic nitrous oxide within proteins by infrared spectroscopy

We report here a comprehensive infrared spectroscopic study of the interactions between the anesthetic nitrous oxide (N2O) and six proteins: lysozyme, cytochrome c, myoglobin, hemoglobin, serum albumin, and cytochrome c oxidase. Sites occupied by N2O molecules within these proteins were characterized. Three types of hydrophobic sites were found within the proteins. One with nu 3 near 2225 cm-1 is likely to be near peptide bond carbonyls; one with nu 3 near 2219 cm-1 may be near a benzene-like structure such as the side chains of phenylalanine and tyrosine; and the other with nu 3 near 2215 cm-1 is likely to be in a nonpolar alkane-like environment provided by the side chains of Leu, Ile, and Val residues. The amount of N2O molecules bound to myoglobin increases as the pH decreases from 9.2 to 5.2. N2O-protein interactions produced no detectable changes in the ligand-binding pockets of myoglobin, hemoglobin, and cytochrome c oxidase. N2O-induced secondary structure changes were detected only in the fully reduced cytochrome c oxidase, not in the fully oxidized oxidase and the other five proteins. N2O-induced conformational changes in the alpha beta-interface of hemoglobin and the h2 and h3 alpha-helices of human serum albumin were detected by monitoring the S-H stretch vibrations of cysteine residues. These findings provide direct evidence that anesthetic N2O interacts with proteins and occupies sites in the interior of the proteins.

Common characteristics shared by different differential phase contrast imaging methods

There are many variations of differential phase contrast imaging methods. Although these imaging methods are different in configuration, they are alike in imaging by extracting differential phase information through the evaluation of the refraction angles. In this paper, we investigate common characteristics shared by various different differential phase contrast imaging methods.

[Gene analysis of five inherited factor V deficiency cases]

OBJECTIVE

To identify gene mutations involved in five cases of inherited factor V (FV) deficiency.

METHODS

Activity of FV was determined by one-stage clotting assay using FV-deficiency plasma, and FV antigen by an ELISA assay. All the exons and exon-intron boundaries of FV gene were amplified by PCR and then DNA sequencing. Restriction enzyme analysis was used to analyze the probands, their family members and healthy volunteers.

RESULTS

Both activity and antigen of FV in the 5 patients were extremely lower compared with that of normal mixed plasma. Six mutations were identified in these 5 patients, G69969T (G2079V), C45533T (R712Ter), C46796T (R1133Ter), G45366A (C656Y), C46253T (R952C) and G16088C (D68H), the latter three were novel mutations reported for the first time and the C46253T (R952C) was the first missense mutation reported in B domain. The result of sequencing or restriction enzyme analysis showed that the three novel missense mutations were not caused by single nucleotide polymorphisms.

CONCLUSION

Gene mutations in 5 type I inherited FV deficiency of patients including 2 nonsense mutations and 4 missense mutations identified which led to the instability of FV protein and the reducing of FV: Ag in the plasma.

Mutual inhibition between quinine and etoposide by human liver microsomes. Evidence for cytochrome P4503A4 involvement in their major metabolic pathways

The mutual inhibition between quinine and etoposide with their major metabolic pathways (i.e. quinine 3-hydroxylation and etoposide 3'-demethylation) was examined in vitro by human liver microsomes. Etoposide inhibited quinine 3-hydroxylation in a concentration-dependent manner with a mean IC50 of 65 microM. The mean maximum inhibition by etoposide (100 micro) of quinine 3-hydroxylation was about 60%. Similarly, etoposide 3'-demethylation was inhibited by quinine in a concentration-related manner with a mean IC50 value of 90 microM. The mean maximum inhibition by quinine (100 M) of etoposide 3'-demethylation was about 52%. An excellent correlation (r = 0.947, p < 0.01) between quinine 3-hydroxylase and etoposide 3'-demethylase activities in six different human liver microsomes was observed. Two inhibitors of CYP3A4, ketoconazole (1 microM) and troleandomycin (100 microM), inhibited quinine 3-hydroxylation by about 90% and 80%, and etoposide 3'-demethylation by about 75% and 65%, respectively. We conclude that quinine and etoposide mutually inhibit the metabolism of each other, consistent with the previous finding that CYP3A4 catalyzes the metabolism of both substrates.

The In vitro hepatic metabolism of quinine in mice, rats and dogs: comparison with human liver microsomes

The major metabolic pathway of quinine in the human has been shown to be 3-hydroxylation mediated mainly by human cytochrome P450 (CYP) 3A4. In this extended in vitro study, quinine 3-hydroxylation was further investigated using microsomes from mouse, rat, dog and human livers and was compared among them in terms of the in vitro enzyme-kinetic parameters and quinine-drug interaction screenings. In all species, 3-hydroxyquinine was the principal metabolite of quinine. There was intra- and interspecies variability among all the kinetic parameters, and dogs exhibited a closer resemblance to humans in terms of the mean kinetic data. Ketoconazole and troleandomycin inhibited the 3-hydroxylation of quinine in all species. Both alpha-naphthoflavone and diazepam showed an interspecies difference in quinine 3-hydroxylation: a trend toward an activation in dog and human, and a significant inhibition in mouse and rat, liver microsomes. Antisera raised against rat CYP3A2 strongly inhibited quinine 3-hydroxylation by about 96, 84 and 92% with mouse, rat and dog liver microsomes, respectively, but neither anti-rat 2C11 and 2E1 antisera did so with rat liver microsomes. Primaquine, doxycycline and tetracycline substantially inhibited the formation of 3-hydroxyquinine in rat, dog and human species, but proguanil had no such effect in any species. Chloroquine inhibited quinine 3-hydroxylation with rat and dog liver microsomes but not with human liver microsomes. There was a significant correlation (r = 0.986, P < .001) between the CYP3A contents and the formation rates of 3-hydroxyquinine in eight human liver microsomal samples. It is concluded that 3-hydroxyquinine is a main metabolite of quinine and that CYP3A/Cyp3a is a principal isoform involved in this metabolic pathway in the respective (rat, dog and human/mouse) species tested. The dog and possibly the rat may be qualitatively and quantitatively suitable animal models for exploring the quinine 3-hydroxylase activity and for screening quinine-drug interactions in vitro, at certain inconsistency with the human liver microsomal data.

[Establishment and characterization of leukemic cell line U937 stably expressing exogenous RbAp46]

To establish leukemic cell lines stably transfected by RbAp46 gene, electroporation was performed after optimizing the transfection condition for suspended cells. Under conditions of low voltage and high capacitance, RbAp46 was transfected into U937 by electroporation. Individual clones selected with G418 for 3 weeks were isolated. The integration and the protein levels of the exogenous RbAp46 in transfectants were determined by PCR and Western blot analysis, respectively. The subclone expressing high level of RbAp46 was then established. Viability of transfected cells was assayed by trypan blue exclusion. Cell number was counted daily to determine the growth rate. The results showed that growth rate of U937 cell lines expressing exogenous RbAp46 was about 50% lower than that in control. It is concluded that leukemic cell lines stably expressing exogenous RbAp46 were established and overexpression of RbAp46 inhibits the growth of U937 leukemic cells.