[Changes of lipoprotein lipase and hepatic lipase and their significance in gallstone formation in rabbit model]

This experiment was made to investigate the changes of lipoprotein lipase(LPL) and hepatic lipase (HL) activity and their effects on gallstone formation in rabbit model in which the stones were induced by high cholesterol diet. Activities of plasma LPL and HL were determined; other data including concentration of plasma lipoprotein cholesterol, concentration of bile cholesterol and bile acids were also obtained. The results showed that with the rabbits continuously fed on high cholesterol diet, LPL activity heightened markedly (P < 0.05), and HL activity increased gradually (3 and 4 weeks groups vs control group, P < 0.05). The changes of concentration of plasma VLDL-C and LDL-C were the same as that of LPL activity, but the concentration of plasma HDL-C, HDL2-C, HDL3-C and bile acids showed no significant changes (P > 0.05). These results suggest that the heightened activities of LPL and HL might make the liver take up more cholesterol, secrete it into the bile duct and hence accelerate gallstone formation.

DMPS-arsenic challenge test. II. Modulation of arsenic species, including monomethylarsonous acid (MMA(III)), excreted in human urine

The administration of sodium 2,3-dimercapto-1-propane sulfonate (DMPS) to humans chronically exposed to inorganic arsenic in their drinking water resulted in the increased urinary excretion of arsenic, the appearance and identification of monomethylarsonous acid (MMA(III)) in their urine, and a large decrease in the concentration and percentage of urinary dimethylarsinic acid (DMA). This is the first time that MMA(III) has been detected in the urine. In vitro biochemical experiments were then designed and performed to understand the urinary appearance of MMA(III) and decrease of DMA. The DMPS-MMA(III) complex was not active as a substrate for the MMA(III) methyltransferase. The experimental results support the hypothesis that DMPS competes with endogenous ligands for MMA(III), forming a DMPS-MMA complex that is readily excreted in the urine and points out the need for studying the biochemical toxicology of MMA(III). It should be emphasized that MMA(III) was excreted in the urine only after DMPS administration. The results of these studies raise many questions about the potential central role of MMA(III) in the toxicity of inorganic arsenic and to the potential involvement of MMA(III) in the little-understood etiology of hyperkeratosis, hyperpigmentation, and cancer that can result from chronic inorganic arsenic exposure.

Acute laryngeal oedema and the yellow nail syndrome

A complication of yellow nail syndrome after pleurodesis is presented. After endotracheal extubation the patient developed delayed acute laryngeal oedema requiring re-intubation. We postulate that the combination of lymphatic defect and airway trauma from the double lumen endotracheal tube were contributory to the oedema. If endotracheal intubation is performed, these patients should be observed for 48 h.

Sympathetic inhibition with clonidine prolongs survival in experimental chronic heart failure

Activation of the sympathetic nervous system is associated with increased mortality in congestive heart failure (CHF), and inhibition of the sympathetic nervous system by centrally acting sympatholytic agents has been shown to have beneficial effects on hemodynamics in these patients. However, the effect of sympathetic inhibition on survival in CHF is not clear. In the present study, the effect of sympathetic inhibition with clonidine on survival was examined in a rat model of heart failure. Myocardial infarction and heart failure was induced in rats by ligation of the left coronary artery and sham-operated rats served as the control. Two weeks after surgery, the ligated rats were randomly assigned to the clonidine (100 microg kg(-1) d(-1), n=30) group or the placebo (vehicle, n=31) group. All rats were followed daily for a 1-year period or until spontaneous death. Compared with placebo therapy, clonidine treatment reduced systolic blood pressure and heart rate throughout the experimental period. The plasma norepinephrine level determined at the end of the experiment was also reduced. Long-term sympathetic inhibition with clonidine treatment improved 1-year survival (50% vs. 22.6%, P<0.05) after surgery in this rat model of CHF.

Amplitude and phase control of ultrashort pulses by use of an acousto-optic programmable dispersive filter: pulse compression and shaping

We demonstrate experimentally that an arbitrary phase and amplitude profile can be applied to an ultrashort pulse by use of an acousto-optic programmable dispersive filter (AOPDF). Our filter has a large group-delay range that extends over 3 ps and a 30% diffraction efficiency over 150 THz. Experiments were conducted on a kilohertz chirped-pulse amplification laser chain capable of generating 30-fs pulses without additional pulse shaping. Compensating for gain narrowing and residual phase errors with an AOPDF in place of the stretcher results in 17-fs transform-limited pulses. Arbitrary shaping of these 17-fs pulses is also demonstrated in both the temporal and the spectral domains.

Structural basis for substrate specificity of protein-tyrosine phosphatase SHP-1

The substrate specificity of the catalytic domain of SHP-1, an important regulator in the proliferation and development of hematopoietic cells, is critical for understanding the physiological functions of SHP-1. Here we report the crystal structures of the catalytic domain of SHP-1 complexed with two peptide substrates derived from SIRPalpha, a member of the signal-regulatory proteins. We show that the variable beta5-loop-beta6 motif confers SHP-1 substrate specificity at the P-4 and further N-terminal subpockets. We also observe a novel residue shift at P-2, the highly conserved subpocket in protein- tyrosine phosphatases. Our observations provide new insight into the substrate specificity of SHP-1.

Profiles of cytokine mRNAs in the skin and lymph nodes of SENCAR mice treated epicutaneously with dibenzo[a,l]pyrene or dimethylbenz[a]anthracene reveal a direct correlation between carcinogen-induced contact hypersensitivity and epidermal hyperplasia

The potent carcinogenicity of dibenzo[a,l]pyrene (DB[a,l]P) in mouse skin is associated with an inflammatory response and a striking epidermal hyperplasia. The mechanism of these tissue responses is not known. However, a recent study has shown DB[a,l]P to be a contact sensitizer. In view of the programmed expression of cytokines during induction of contact hypersensitivity (CHS) and elicitation of CHS reactions, we analyzed cytokine mRNAs in treated skin and draining lymph nodes of SENCAR mice, at selected times after a single, epicutaneous application of DB[a,l]P or dimethylbenz[a]anthracene (DMBA), a substantially weaker carcinogen and a weaker contact sensitizer than DB[a,l]P. Cytokine mRNAs were quantified by first-strand DNA synthesis with reverse transcriptase (RT) and DNA amplification by the polymerase chain reaction (PCR). Histopathology of treated skin was determined in the same experiments. Time-response profiles of interferon (IFN) gamma and interleukin (IL) 2 in the DLN and IL1beta, IL10, tumor necrosis factor (TNF) alpha, and IL4 mRNAs in the skin of mice treated with 200 nmol of DB[a,l]P were in remarkable agreement with established profiles in mice treated with conventional contact sensitizers, e.g., oxazolone or dinitrochlorobenzene. Strong upregulation of DLN IFNgamma mRNA coupled with little change in IL 2 mRNA suggested a CD8(+) T-cell response characteristic of CHS induction. Coordinate expression of epidermal IL1beta, TNFalpha, and IL10 mRNAs, 24 h after DB[a,l]P treatment, was also characteristic of CHS induction. IL1beta and IL10 are upregulated by allergens and not by chemical irritants. Time-response profiles of epidermal IL1beta, TNFalpha, IL10, and IL4 mRNAs, 3-14 d after DB[a,l]P treatment, corresponded with expression of these cytokines during elicitation of CHS reactions. Epidermal IL4 is specifically upregulated during CHS reactions. Cytokine mRNA responses were dose-dependent (50, 100, and 200 nmol of DB[a,l]P) and markedly weaker in animals treated with 400 nmol of DMBA. Significantly, the intensity of epidermal hyperplasia correlated with the strength of the cytokine mRNA signals in DLN and skin. In conclusion, our data support carcinogen-specific CHS as a mechanism by which the very potent carcinogen DB[a,l]P induces epidermal hyperplasia, a requirement for tumor promotion in mouse skin.

Effects of third ventricle injection of norepinephrine analogue on LH secretion of the non-laying SIJI goose

The effect of norepinephrine analogue (NA) and norepinephrine antagonists on luteinizing hormone releasing hormone (LHRH) secretion in geese was investigated by monitoring serum levels of LH. Twenty non-laying geese were selected and randomly assigned to 4 groups of 5 each. The geese received a single intraventricular injection of saline (control), NA (12 microg/6 microl), phentolamine (1 microg/6l) plus NA or yohimbine (10 microg/6 microl). Phentolamine, a non-selective adrenoreceptor blocker was given 5 min before NA, but yohimbine, an alpha2-adrenoreceptor blocker, was delivered without NA injection. The results showed that serum levels of LH began to increase 20 min after injection of NA, and that high serum levels of LH were maintained until 105 min, followed by a decline to the basal level 125 min later. Significantly high levels of serum LH were observed at 50 and 105 min after the injection as compared with the respective control. Treatment with phentolamine completely blocked the stimulatory effect of NA on serum levels of LH in NA treated geese. Serum levels of LH increased by yohimbine treatment 5 min after the injection and the high levels of serum LH were maintained until 125 min later. Five out of 8 points were significantly high as compared with their respective control values. The present study also suggested that there is presynaptic modulation in the a-noradrenergic neural pathways which mediate the release of LHRH, and that this modulation may be carried out by alpha2-adrenoreceptor blocker.

Biological activities of antibodies elicited by lipooligosaccharide based-conjugate vaccines of nontypeable Haemophilus influenzae in an otitis media model

Vaccination of chinchillas with nontypeable Haemophilus influenzae (NTHi) lipooligosaccharide (LOS) conjugates protected against otitis media. Correlations between the levels of conjugate-induced LOS antibodies (Abs) in sera and middle ear fluids (MEFs) and Ab-mediated biological functions and protection were examined. Following parenteral vaccination and middle ear challenge, all vaccinated animals, but none of the controls, had high titers of anti-LOS in their sera and MEFs. There was a correlation between the levels of anti-LOS IgG + M, IgG or IgA in the sera and in the MEFs (P < 0.001). An inverse correlation was found between the level of serum IgG + M and bacterial counts and between the levels of MEF Abs and bacterial counts at the early postchallenge stage (P < 0.05). Of the 39 vaccinated animals, 44% showed complete protection against otitis media, 46% (18/39) of their sera inhibited adherence of NTHi to human epithelial cells, 49% (19/39) demonstrated bactericidal activity and 49% (19/39) showed opsonophagocytic activity. In contrast, none of the controls (19) were protected, none of their sera inhibited bacterial adherence or had bactericidal activity and only 21% showed opsonophagocytosis. Our interpretation is that vaccine-induced LOS Abs transuded into the middle ear and conferred immunity to NTHi by binding to LOS of NTHi, inhibition of NTHi adherence to epithelial cells and complement-mediated bacteriolysis (or opsonophagocytosis).

Studies on the substrate specificity of human intestinal UDP- lucuronosyltransferases 1A8 and 1A10

Although the liver has been considered the most important organ involved in glucuronidation, recent studies have focused on the role of the gastrointestinal tract in the glucuronidation of xenobiotics and endobiotics. Two UDP-glucuronosyltransferase (UGT) isoforms of human intestinal mucosa, which are absent in liver, have been identified by reverse transcriptase-polymerase chain reaction. mRNAs of UGT1A8 and UGT1A10 were detected in both the small intestine and the colon. The corresponding cDNAs for UGT1A8 and UGT1A10 were cloned from ileal RNA and inserted into the mammalian expression vector pcDNA3. Transfection of the cDNAs into human embryonic kidney 293 cells was carried out and stable expression was achieved. Membrane preparations from human embryonic kidney 293 cells expressing either UGT1A8 or UGT1A10 were isolated and the expression of each isoform was analyzed by Western blot. The catalytic activity of stably expressed UGT1A8 toward catechol estrogens, coumarins, flavonoids, anthraquinones, and phenolic compounds was much higher than that of UGT1A10. UGT1A8, but not UGT1A10, catalyzed the glucuronidation of opioids, bile acids, fatty acids, retinoids, and clinically useful drugs, such as ciprofibrate, furosemide, and diflunisal. These studies suggest that human intestinal UGTs may play an important role in the detoxification of xenobiotic compounds and, in some cases, limit the bioavailability of therapeutic agents.

[Observation of distortion product otoacoustic emissions in recovery course of sudden deafness]

OBJECTIVE

To realize the DPOAE resulting in sudden deafness and to investigate the changes of OAE in the recovery course of sudden deafness.

METHOD

The basic characters of distortion product OAE (DPOAE) were studied in 60 ears of 30 cases with sudden deafness. The treatment and following-up were carried on too.

RESULT

The incidence and amplitude of OAEs in the affected ears were lower than that of normal ears and normal group, and the threshold of DPOAE was higher too. In the recovery course the amplitude and threshold of DPOAE were improved with the restoration of auditory threshold, but the restoring rate (RR) of auditory threshold was higher.

CONCLUSION

The DPOAE in sudden deafness implies a serious sensorineural hearing loss. In the recovery course, the amplitude and threshold of DPOAE is later than that of the pure-tone behavioral threshold, which implies that DPOAE is a sensitive and direct way in reflecting the function of cochlea.

Projections of the dorsal motor nucleus of the vagus to cardiac ganglia of rat atria: an anterograde tracing study

We injected the anterograde fluorescent tracer 1,1'-dioleyl-3,3,3',3'-tetramethylindocarbocyanine methanesulfonate (DiI) into the dorsal motor nucleus of the vagus (DmnX), counterstained the cardiac ganglia with Fluorogold (FG), and used confocal microscopy to examine the distributions and different types of DmnX fibers in wholemounts of the atria. We also quantified the number of DmnX cardiac axons and the number of innervated cardiac principal neurons (PNs). Rats with unilateral DiI injections were used in three different experiments, including unilateral FG soaking of cervical vagal trunks, intracranially rhizotomizing the vagal afferent roots, or contralaterally sectioning the cervical vagus. These manipulations indicated that DiI-labeled cardiac fibers were exclusively from the DmnX. Our observations established that: (1) three major ganglionic plexuses were localized in the epicardium; (2) both sides of the DmnX supplied significant fibers to each of the plexuses; (3) these cardiac efferents formed dense basket terminals around individual PNs; (4) collaterals of individual DmnX fibers diverged, producing calyx endings on multiple PNs; (5) small intensely fluorescent (SIF) cells in the cardiac plexuses were innervated pericellularly; (6) individual axons could innervate both PNs and SIF cells; (7) the total number of DmnX fibers were in the range of [68, 96; left] and [67, 115; right]; (8) these fibers innervated 709 (left) and 494 (right), or at least 18% and 12%, of the PNs, respectively; and (9) vagal preganglionics exhibited a degree of lateralization: Significantly more PNs were contacted by fiber varicosities in the sinoatrial plexus than in the atrioventricular plexus after right DmnX injections. In summary, the present observations suggest that the DmnX plays a significant role(s) in controlling the heart.

[Qualitative and quantitative studies on Chinese drug maidong]

OBJECTIVE

To explore a better approach to controlling the quality of Maidong.

METHOD

The differences between Ophiopogon japonicus and the plants belonging to Liriope genus were identified by TLC. The total saponins in plants collected from different areas were determined by spectrophotometry, using HClO4 as the staining agent.

RESULTS

The quantity of Maidong markedly varies with producing areas.

CONCLUSION

This method is convenient and effective, and the MeOH extract of samples can be determined directly after reaction with HClO4 without preliminary treatment. The RSD was 0.75% (n = 5).

Glucuronidation of 2-hydroxyamino-1-methyl-6-phenylimidazo[4, 5-b]pyridine by human microsomal UDP-glucuronosyltransferases: identification of specific UGT1A family isoforms involved

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine is a heterocyclic aromatic amine found in cooked meats and dietary exposure to PhIP has been implicated in the etiology of colon cancer in humans. PhIP, along with other heterocyclic aromatic amines, requires metabolic activation to exhibit genotoxic effects. PhIP is initially oxidized by the activity of cytochrome P4501A2 to produce 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP), a reaction occurring primarily in the liver. Whereas subsequent biotransformation of N-OH-PhIP via acetylation or sulfation can produce reactive electrophiles that readily bind to DNA, N-glucuronidation, catalyzed by UDP-glucuronosyltransferases (UGTs), functions as a detoxification mechanism. Although hepatic glucuronidation of N-OH-PhIP has been well characterized, the extrahepatic metabolism of this compound is poorly understood. Studies in our laboratory now indicate that the intestinal tract, and particularly the colon, is a significant site of glucuronidation of N-OH-PhIP. When assays were performed with microsomes prepared from the mucosa of the intestinal tract, it was determined that glucuronidation of N-OH-PhIP occurs throughout the intestinal tract, with activity approximately three times higher in the colon as that found in the upper intestine. Glucuronidation rates from colon microsomes showed considerable interindividual variability and incubation with N-OH-PhIP yielded two glucuronides. HPLC analysis showed that the predominant product formed is the N-OH-PhIP-N2-glucuronide, while the N3-glucuronide accounts for <10% of the total glucuronidation product. These rates approach the rates found in human liver microsomes, demonstrating the significance of extrahepatic metabolism of this food-borne carcinogen. Subsequent assays with human recombinant UGTs demonstrated that at least four human UGT isoforms, all from the UGT1A subfamily, are capable of catalyzing the biotransformation of N-OH-PhIP. Members of the UGT2B family available for this study did not conjugate N-OH-PhIP, although immunoinhibition studies in human liver microsomes strongly suggest the involvement of a UGT2B isoform(s) in this organ.

[The feature of pancreatic microcirculatory impairment in caerulein induced acute pancreatitis]

OBJECTIVE

To study the feature of pancreatic microcirculatory impairment in caerulein-induced acute pancreatitis.

METHODS

The AP model of subcutaneous injection of caerulein was studied by intravital fluorescence microscopy of erythrocytes labeled by FITC (FITC-RBC) and by scanning electron microscopy of vascular corrosion casts and light microscopy of Chinese ink-injected/cleared tissues.

RESULTS

Animals treated with caerulein showed hyper-amylases. Contractions of intralobular arteriolar sphincter, presence of vacuoles in all the layers of sphincter, gross irregularity in capillary network of acini were observed in caerulein-induced groups. The decrease of pancreatic capillary blood flow (P < 0.01), reduction of functional capillary density, and irregular intermittent perfusion (P < 0.05) were found.

CONCLUSIONS

Impairment and contraction of pancreatic intralobular arteriolar sphincter are the initial microcirculatory lesions in the early phase of acute pancreatitis induced by Caerulein, and play a key role in the pancreatic ischemia and pancreatic microvascular failure in acute pancreatitis.

[Antiviral action of combined use of rhizoma Polygoni cuspidati and radix Astragali on HSV-1 strain]

OBJECTIVE

The clinical action of combined use of Rhizoma Polygoni Cuspidati and Radix Astragali on HSV-1 was investigated with a view to developing a new antiviral drug.

METHOD

The action was analyzed by way of plaque reduction assay and median-effect principle.

RESULTS

In the HEp-2 cell system, if the combination ratio of Rhizoma Polygoni Cuspidati and Radix Astragali was 1(ED50):1(ED50) then, (1) In directly annihilating HSV-1 F strain, when the plaque reduction rate was 20%-80%, and the combination index was < 1.0, there was synergism. (2) In inhibiting the multiplication of HSV-1 F strain, when the plaque reduction rate was 20%-60%, and the combination index was < 1.0, there was also synergism. (3) In blockading HSV-1 F strain infection, when the plaque reduction rate was 20%-90% and the combination index was < 1.0, there was synergism. So this ratio of 1(ED50):1(ED50) should be the first choice for combination.

CONCLUSION

The treatment index of the above two Chinese medicinal herbs equals 10(3), and the cytotoxicity is not potentiated, indicating that the combination is helpful as a virucide for HSV-1 F strain.

Amplitude and chirp characterization of high-power laser pulses in the 5-fs regime

Frequency-resolved optical gating (FROG) based on second-harmonic generation has been demonstrated to be capable of high-fidelity measurement of the electric-field envelope and of the temporal evolution of the instantaneous carrier frequency of 0.1-TW 5-fs pulses without the need for any correction for systematic experimental errors. At a 1-kHz repetition rate, pulse energies of a few microjoules are sufficient for reliable FROG characterization of pulses with durations down to the single-cycle regime. The results obtained reveal that carefully designed hollow-fiber chirped-mirror compressors are able to deliver high-power sub-10-fs pulses with a smooth Gaussianlike leading edge that has an intensity contrast of approximately 10(-2) .