A multifunctional fluorescent probe for sequential detection of hydrogen sulfide and pH in foodstuffs, living cells and mice

BACKGROUND

Cancer as a leading cause of premature death worldwide has become a major threat to human health due to the high incidence and mortality. Monitoring tumor markers are reliable and significantly important for early detection of cancers. In complex biological systems, it is of great urgency but still remains challenging to conceive a fluorescent probe with multiple tumor markers detection property. Hydrogen sulfide (H2S) and pH are two target biomarkers for diagnosis of early cancer. The preparation of a novel probe with H2S and pH dual detection functions is highly anticipated.

RESULTS

Herein, a novel sequential detection probe HTPQ-HS for H2S and pH has been developed. In this system, HPQ (2-(2 -hydroxyphenyl)-4(3H)-quinazolinone) structure combined with triphenylamine is applied as the fluorophore, and 2, 4-dinitrophenylsulfonyl group is used as the recognition group. In the presence of H2S, HTPQ-HS is transformed into product HTPQ-OH which shows fluorescence enhancement (29-fold) at 525 nm in less than 4 min and further displays repeatable acid-base responsive ability. HTPQ-HS is able to sequentially response to H2S and pH in living cells and does not react directly with pH. Owing to the low cytotoxicity, HTPQ-HS is able to detect exogenous and endogenous H2S in colon cancer cells and mice, monitor H2S in inflammation model and in foodstuffs. As the environment changes from acidic to alkaline, the fluorescence intensity ratio (I470/I530) of product HTPQ-OH changes remarkably, illustrating the ratiometric fluorescent responsiveness to pH.

SIGNIFICANCE AND NOVELTY

A multifunctional fluorescent probe HTPQ-HS for sequential detection of H2S and pH is synthesized. Probe HTPQ-OH realizes the monitoring of dynamic changes in intracellular pH and displays prospective application in security printing. We expect that our work could offer an important guidance on the development of multifunctional fluorescent probes for visualizing H2S and pH in biology and environment.

A lysosome-targeted fluorescent probe based on a BODIPY structure for Cys/Hcy detection

Cysteine (Cys) and homocysteine (Hcy) are important biothiols in living organisms. They play important roles in a variety of physiological and pathological processes. Therefore, it is very important to design an optical probe for the selective detection of Cys/Hcy. Herein, we report the design and synthesis of a fluorescent probe NBD-B-T based on a boron-dipyrromethene (BODIPY) structure, which showed an excellent lysosome targeting ability and an outstanding Cys/Hcy detection capacity. For NBD-B-T, the sensing group 7-nitro-2,1,3-benzoxadiazole (NBD) and the lysosomal targeting group morpholine were introduced. The results show that the NBD-B-T probe can detect Cys/Hcy with fluorescence emission turn-on performance. The low detection limits of this probe are about 76.0 nM for Hcy and 97.6 nM for Cys, respectively. The NBD-B-T probe has a low detection limit, high stability, and excellent selectivity and sensitivity. More importantly, the NBD-B-T can target lysosome, and simultaneously detect the Cys/Hcy in living cells.

[Quality of life and risk factors in patients with herpes zoster]

Objective: To evaluate the quality of life and influencing factors of patients with herpes zoster (HZ) seen in hospitals. Methods: Based on Zoster Brief Pain Inventory (ZBPI) and Five-level EuroQol Five-dimensional Questionnaire (EQ-5D-5L), a cross-sectional survey was conducted to evaluate the pain severity and quality of life of 332 HZ cases seen in 22 hospitals of Lu'an City (Anhui Province), Zibo City (Shandong Province) and Tongchuan City (Shaanxi Province) from October to December 2021. The censored least absolute deviations (CLAD) model was used to analyze the related factors affecting the changes of patients' health utility values. Results: The 45.5% of 332 HZ cases were male. The median (Q₁,Q₃) age was 59 (50, 68) years. 59.64% of them assessed by ZBPI had moderate to severe pain in the past 24 hours (worst pain score≥5), and that of PHN cases was 84.8%(39/46). 77.7% (258/332), 77.4% (257/332) and 74.1% (246/332) of all patients reported that pain interfered with sleep, mood and general activities, respectively. Aging [β_40-49y (95%CI)=-0.11 (-0.15, -0.08); β_50-59y (95%CI)=-0.03 (-0.05, 0.00); β_60-69y (95%CI)=-0.09 (-0.12, -0.06); β_70-90y(95%CI)=-0.16 (-0.19, -0.12)], working status (unemployed) [β_farmer (95%CI)=0.15 (0.13, 0.18); β_retirees(95%CI)=0.21 (0.18, 0.24); β_employee (95%CI)=0.13 (0.10, 0.16) ], complications[β_PHN (95%CI)=-0.08 (-0.13, -0.04); β_{other complications} (95%CI)=-0.12 (-0.15, -0.08)], within 30 days after onset [β(95%CI)=-0.01 (-0.03, 0.01)] and treatment [β_{other complications} (95%CI)=-0.09 (-0.11, -0.06)] were related factors for the decline of health utility value (all P values <0.05). Conclusions: More than half of the patients with HZ had moderate to severe pain in the past 24 hours, which had a serious negative impact on the physical and mental health of the patients. Elderly patients, acute patients and patients with complications had lower health utility values and worse health status. We suggest that eligible people be vaccinated with HZ vaccine as soon as possible.

Bioconversion of Hg0 into HA-Hg for simultaneous removal of Hg0 and NO in a denitrifying membrane biofilm reactor

Bacterial mercury oxidation coupled to denitrification offers great potential for simultaneous removal of elemental mercury (Hg⁰) and nitric oxide (NO) in a denitrifying membrane biofilm reactor (MBfR). Four potentially contributory mechanisms tested separately, namely, membrane gas separation, medium absorption, biosorption and biotransformation, which contributed 4.9%/7.2%, 8.1%/8.9%, 38.8%/9.5% and 48.2%/84.9% of overall Hg⁰/NO removal in MBfR. Herein, Hg⁰ bio-oxidation, oxidative Hg⁰ biosorption and denitrification played leading roles in simultaneous removal of Hg⁰ and NO. Living microbes performed simultaneous Hg⁰ bio-oxidation and denitrification, in which Hg⁰ as electron donor was biologically oxidized to oxidized mercury (Hg²⁺), while NO as the terminal electron acceptor was denitrified to N₂. The Hg²⁺ further complexed with humic acids in extracellular polymeric substances via functional groups (-SH, -OH, -NH^- and -COO^-) and formed humic acids bound mercury (HA-Hg). Non-living microbial matrix performed oxidative Hg⁰ biosorption, in which Hg⁰ may be physically adsorbed by cellular matrix, then non-metabolically oxidized to Hg²⁺ via oxidative complexation with -SH in humic acids and finally cleavage of S-H bond and surface charge transfer led to formation of HA-Hg. Therefore, bioconversion of Hg⁰ to HA-Hg by Hg⁰ bio-oxidation and oxidative Hg⁰ biosorption coupled with NO denitrification to N₂ dynamically cooperated to accomplish simultaneous removal of Hg⁰ and NO in MBfR.

Photocatalytic membrane combined with biodegradation for toluene oxidation

Photocatalytic membrane coupled to biodegradation offers potential for degrading volatile organic compounds (VOCs) in photocatalytic membrane biofilm reactor. An intimately coupled photocatalysis and biodegradation reactor was operated in continuous operation for 500 days to treat simulated waste gas containing toluene. Toluene removal efficiency obtained 99%, with the elimination capacity of 550 g m^-3·h^-1. Membrane photocatalysis coupled to biodegradation was created to improve toluene removal from 11 to 20%. The dominant genera were Lysinibacillus, Hydrogenophaga, Pseudomonas at 30 d, Rudaea, Dongia, Litorilinea at 230 d xyl, Tod, Tcb, Bed, Tmo, Tbu, Tou, Dmp, Cat were functional genes of toluene metabolism, as shown by16S rDNA and metagenomic sequencing. Photocatalysis destroyed part of the toluene into biodegradable intermediates that were immediately mineralized by microorganisms in biofilm, some toluene was directly degraded by toluene degrading bacterial community into carbon dioxide and water. The novel hybrid photocatalytic membrane biofilm reactor is a cost-effective and robust alternative to VOCs treatment.

Simultaneous mercury oxidation and NO reduction in a membrane biofilm reactor

This work demonstrates bacterial oxidation of mercury (Hg⁰) coupled to nitric oxide (NO) reduction in a denitrifying membrane biofilm reactor (MBfR). In 93 days' operation, Hg⁰ and NO removal efficiency attained 90.7% and 74.1%, respectively. Thauera, Pseudomonas, Paracoccus and Pannonibacter played dual roles as Hg⁰ oxidizers and denitrifiers simultaneously. Denitrifying bacteria and the potential mercury resistant bacteria dominated the bacterial community. Denitrification-related genes (norB, norC, norD, norE, norQ and norV) and enzymatic Hg⁰ oxidation-related genes (katG, katE) were responsible for bacterial oxidation of Hg⁰ and NO reduction, as shown by metagenomic sequencing. XPS, HPLC-ICP-MS and SEM-EDS indicated the formation of a stable mercuric species (Hg²⁺) reasulting from Hg⁰ oxidation in the biofilm. Bacterial oxidation of Hg⁰ was coupled to NO reduction in which Hg⁰ served as the initial electron donor while NO served as the terminal electron acceptor and thereby redox between Hg⁰ and NO was formed. MBfR was capable of both Hg⁰ bio-oxidation and denitrifying NO reduction. This research opens up new possibilities for application of MBfR to simultaneous flue gas demercuration and denitration.

2,3-Dipentyldithieno[3,2-f:2',3'-h]quinoxaline-Based Organic Dyes for Efficient Dye-Sensitized Solar Cells: Effect of π-Bridges and Electron Donors on Solar Cell Performance

Five novel metal-free organic dyes DQ1-5 containing a dipentyldithieno[3,2-f:2',3'-h]quinoxaline (DPQ) unit were synthesized and applied in dye-sensitized solar cells (DSSCs), where DPQ was employed as a π-spacer for the first time. Their photophysical, electrochemical, and theoretical calculations and photovoltaic properties were systematically investigated. All the five dyes show broad photoresponse. Especially the absorption edges of DQ3-5 extend to 800 nm on the TiO2 films. The inserted electron-rich unit 3,4-ethylenedioxythiophene or electron-withdrawing group benzothiadiazole (BTD) in DPQ-based dyes can greatly influence the optoelectronic properties of the dyes. In addition, the different electron donors also significantly affect the performance of the DSSCs. Under standard global AM 1.5 solar light conditions, the DQ5 sensitized solar cell obtained a power conversion efficiency of 7.12%. The result indicates that the rigid DPQ-based organic dye is a promising candidate for efficient DSSCs.

Expression of aberrant beta-catenin and impaired p63 in craniopharyngiomas

Craniopharyngiomas are rare, histologically benign, non-neuroepithelial epithelial tumors arising from the sellar region, the molecular pathogenesis of CPs is yet not understood. The aim of the present study was to assess expression of aberrant beta-catenin and impaired p63 in 66 craniopharyngiomas included 51 adamantinomatous craniopharyngiomas and 15 squamous papillary craniopharyngiomas. On immunohistochemistry, 47 out of 51 adamantinomatous craniopharyngiomas, but not squamous papillary craniopharyngiomas, showed strong nuclear/cytoplasmic expression for beta-catenin predominantly in compactly cohesive epithelial cells within the whorl-like arrays where ki-67 was almost absent and rarely in palisaded cells where ki-67 was mainly present. P63 overexpression was observed in 45 out of 51 adamantinomatous craniopharyngiomas and 14 out of 15 squamous papillary craniopharyngiomas. P63 stained not only in the nuclei of basal layer cells but also within the whorl-like arrays in adamantinomatous craniopharyngiomas and uniformly in squamous papillary craniopharyngiomas. Using quantitative real time polymerase chain reaction techniques to correlate p63 protein expression with p63 mRNA levels, TAp63 isoforms mRNA was reduced, whereas DeltaNp63 mRNA elevated at levels in 5 snap frozen tissue samples with multiple large p63 positive cell clusters compared with normal tissues. In conclusion, the present study confirmed that the two variants of CPs have genetically not only distinctive but also common feature. It demonstrated that cytoplasm/nuclear beta-catenin accumulation is an exclusively characteristic morphology of adaCPs. P63 immunohistochemical overexpression were found in both adaCPs and spCPs variant when analyzed in the same study. Taken together, the impaired p63 expression may be attributed to elevated DeltaNp63 mRNA and reduced TAp63mRNA in CPs.

Salvianolic acid A inhibits platelet activation and arterial thrombosis via inhibition of phosphoinositide 3-kinase

BACKGROUND AND OBJECTIVE

Salvianolic acid A (SAA) is a water-soluble component from the root of Salvia miltiorrhiza Bunge, a herb that is widely used for atherothrombotic disease treatment in Asian medicine. As platelets play pivotal roles in atherothrombogenesis, we studied the effect of SAA on platelet activation and its underlying mechanisms.

METHODS AND RESULTS

SAA dose-dependently inhibited platelet aggregation induced by ADP, thrombin, collagen and U46619. It reduced ADP-enhanced platelet P-selectin expression and fibrinogen binding, which consequently hampered ADP-induced platelet-leukocyte aggregation. SAA also inhibited platelet spreading on fibrinogen, a process mediated by outside-in signaling. Under an arterial shear rate of 1000 s(-1), SAA decreased platelet adhesion on collagen surfaces by approximately 40%. Western blot analysis showed that SAA, like the phosphoinositide 3-kinase (PI3K) inhibitors LY294002 and TGX-221, potently inhibited PI3K, as shown by reduced Akt phosphorylation. The in vitro findings were further evaluated in the mouse model of arterial thrombosis, in which SAA prolonged the mesenteric arterial occlusion time in wild-type mice (35 + or - 2 min without SAA and 56 + or - 4 min with SAA; P < 0.01). Interestingly, SAA could even counteract the shortened arterial occlusion time in Ldlr(tm1Her) mutant mice (21 + or - 2 min without SAA and 45 + or - 4 min with SAA; P < 0.01).

CONCLUSIONS

SAA inhibits platelet activation via the inhibition of PI3K, and attenuates arterial thrombus formation in vivo. Our data suggest that SAA may be developed as a novel therapeutic agent for the prevention of thrombotic disorders.

Correlations between peripheral differential leukocyte counts and carotid atherosclerosis in non-smokers

Substantial evidence clearly indicates the immuno-inflammatory nature of atherosclerosis and the important roles of monocytes and other leukocytes in atherogenesis. The relationship between atherosclerosis and the peripheral monocyte count, however, has been equivocal and uncertain so far. One possible reason may be an opposing effect of different major risk factors of atherosclerosis on the monocyte count, e.g. smoking increases the monocyte count while hypercholesterolemia is accompanied by a lower monocyte count. Since smoking is well shown to increase leukocyte counts prominently in weeks, our study included only non-smokers who participated in a health check program at our hospital from 1996 to 1998 and had received a carotid duplex study with extra payment. Our results revealed the followings: In male non-smokers (n=571), the presence of carotid atherosclerosis was associated with significant increases in the counts of all leukocyte, neutrophil, and monocyte (P<0.005,<0.001 and <0.05, respectively), and, after adjustments for age and body mass index, there were significant positive links between these three leukocyte counts and the severity of carotid atherosclerosis, judged by either the sum score of all carotid plaques or the score of the most severe carotid plaque. On the contrary, in female non-smokers (n=614), there was no significant link between differential leukocyte counts and either the presence or severity of carotid atherosclerosis. These results are compatible with recently recognized sex differences in the mechanism and pathophysiology of atherosclerosis, and together with relevant results in the literature, suggest that monocytes and neutrophils are the main types of leukocytes involved in atherosclerosis.

Peripheral differential leukocyte counts in humans vary with hyperlipidemia, smoking, and body mass index

Reports of diverse relationships between blood concentrations of different lipids and peripheral total leukocyte count, and a unique lower peripheral monocyte count in hypercholesterolemia, have driven us to think that in humans, peripheral differential leukocyte counts may be influenced differently by different types of hyperlipidemia. Our subjects were Taipei residents who attended a regular health check program in our hospital in 1998. A total of 3,282 subjects was enrolled, including 1,677 normolipidemic, 960 untreated borderline hyperlipidemic, and 645 untreated hyperlipidemic subjects. By one-way analysis of variance (ANOVA), we found that different types of hyperlipidemia were associated with significant differences in differential leukocyte counts. In hypertriglyceridemia, the total leukocyte count and counts of all leukocyte subtypes were significantly higher than those in normolipidemia. Pure hypercholesterolemia, by contrast, was associated with a significantly lower monocyte count and no significant difference in other leukocyte counts. By two-way ANOVA adjusted for presence and degree of hyperlipidemia, we found significantly higher counts of total leukocytes and of all leukocyte subtypes in smokers, and significantly positive trends in relationships between body mass index (BMI) and counts of all leukocytes, neutrophils, lymphocytes, and monocytes. By multivariate regression analysis including all subjects, the serum triglyceride (TG) level was positively correlated with total leukocyte count and counts of all subtypes except eosinophils. On the contrary, serum high density lipoprotein-cholesterol had a negative correlation with total leukocyte count and with counts of neutrophils, monocytes, and basophils. In these multivariate regression analyses, there was no significant correlation between lipid levels and eosinophil count, whereas smoking was consistently associated with significantly higher counts of all leukocyte subtypes, including eosinophils. BMI had a significantly positive correlation with counts of all leukocytes, neutrophils, lymphocytes, and monocytes.

Serum level of soluble tumor necrosis factor receptor II (sTNF-R75) is apparently an index of overall monocyte-related infectious and inflammatory activity

BACKGROUND

The serum level of soluble tumor necrosis factor receptor II (sTNF-R75) has been recently found to correlate with the activity and/or severity of several different infectious and inflammatory diseases. These results have led us to presume that the serum sTNF-R75 level reflects the active immune activity of all causes and may correlate well with nonspecific infectious and inflammatory markers such as peripheral leukocyte counts and serum C-reactive protein level.

METHODS

In total, 110 apparently healthy adults, 55 men and 55 women, were enrolled in the study. Serum levels of sTNF-R75, C-reactive protein, globulin, alkaline phosphatase, lactate dehydrogenase, creatinine, urea nitrogen, and counts of neutrophils, lymphocytes, monocytes, eosinophils, and basophils were checked. The relationships between the serum sTNF-R75 level and other parameters were analyzed using the SAS statistical program.

RESULTS

By various statistical methods, the serum sTNF-R75 level showed consistently significant positive links with peripheral monocyte count, serum C-reactive protein level, and two parameters of renal clearance function (serum urea nitrogen and creatinine levels). Serum levels of alkaline phosphatase and lactate dehydrogenase had significant positive links with the serum sTNF-R75 level by multivariate regression analysis. There was no significant link between the serum sTNF-R75 level and counts of neutrophils, lymphocytes, eosinophils, or basophils.

CONCLUSIONS

Our results, together with those of recent reports showing positive correlations between the serum sTNF-R75 level and activities/severities of different infectious and inflammatory diseases, and also that TNF-alpha is principally produced by monocytes and macrophages, suggest that the serum sTNF-R75 level is very probably an index of overall monocyte-related infectious and inflammatory activities.

Identification and characterization of the RNA chaperone activity of hepatitis delta antigen peptides

In this study, we identified an activity of the hepatitis delta antigen that both modulates the cis-cleaving activities of hepatitis delta virus (HDV) genomic RNA fragments and facilitates the trans-cleavage reactions between hammerhead ribozymes and the cognate substrates of various lengths in vitro. Hepatitis delta antigen peptides exert their effect by accelerating the unfolding and refolding of RNA molecules and by promoting strand annealing and strand dissociation. In addition, the stimulatory effect of hepatitis delta antigen peptide on hammerhead catalysis is observed whether the peptide is removed or not by phenol/chloroform extraction prior to the initiation of trans-cleavage reaction. Therefore, hepatitis delta antigen peptide acts as an RNA chaperone. The RNA chaperone domain of hepatitis delta antigen overlaps with the coiled-coil domain that is rich in lysine residues. The RNA binding domains of hepatitis delta antigen previously identified are not required for the RNA chaperone activity identified herein. The RNA chaperone activity of hepatitis delta antigen may be important for the regulation of HDV replication in vivo.

Human corneal epithelial basement membrane and integrin alterations in diabetes and diabetic retinopathy

Corneas of diabetic patients have abnormal healing and epithelial adhesion, which may be due to alterations of the corneal extracellular matrix (ECM) and basement membrane (BM). To identify such alterations, various ECM and BM components and integrin receptors were studied by immunofluorescence on sections of normal and diabetic human corneas. Age-matched corneas from 15 normal subjects, 10 diabetics without diabetic retinopathy (DR), and 12 diabetics with DR were used. In DR corneas, the composition of the central epithelial BM was markedly altered, compared to normal or non-DR diabetic corneas. In most cases the staining for entactin/nidogen and for chains of laminin-1 (alpha1beta1gamma1) and laminin-10 (alpha5beta1gamma1 was very weak, discontinuous, or absent over large areas. Other BM components displayed less frequent changes. The staining for alpha3beta1 (VLA-3) laminin binding integrin was also weak and discontinuous in DR corneal epithelium. Components of stromal ECM remained unchanged even in DR corneas. Therefore, distinct changes were identified in the composition of the epithelial BM in DR corneas. They may be due to increased degradation or decreased synthesis of BM components and related integrins. These alterations may directly contribute to the epithelial adhesion and wound healing abnormalities found in diabetic corneas.

Subtypes and case-fatality rates of stroke: a hospital-based stroke registry in Taiwan (SCAN-IV)

Stroke data bank can afford important information regarding risk factors, pathogenesis, prognosis, etc. By means of hospital-based stroke registry, we investigated the risk factors and case-fatality rates in different types of stroke and transient ischemic attack (TIA) patients at the National Taiwan University Hospital in 1995. After excluding ineligible patients, 995 patients aged 1-98 years (575 men and 420 women) were recruited. Men predominated in all age groups for stroke and TIA in general except for cerebral hemorrhage (CH) in patients aged < 35 years and subarachnoid hemorrhage (SAH) in patients aged > or = 45 years. Of these, 676 (67.9%), 41 (4.1%), 228 (22.9%) and 50 (5%) patients were classified in the categories of cerebral infarction (CI), TIA, CH and SAH, respectively. The CI/CH ratio was 2.96. Hypertension remained one of the most important risk factors for CI, CH and TIA patients. Severe extracranial carotid artery stenosis (> or = 50%) was found in 12% of the CI patients and 27% of the TIA patients, but not found in the CH and SAH patients. Of these patients, the 30-day case-fatality rate was 10.9%, highest in SAH (30%), followed by CH (24.1%) and CI (5.6%). There were 41 in-hospital stroke patients who had significantly higher case-fatality rates than the other stroke patients (P<0.001 for all stroke, CI and CH patients by chi2 test). As compared to the previous stroke registries in Taiwan, there is a secular trend of increasing CI/CH ratios. These findings in Taiwan were compared with those in other populations, including other Asian, Caucasian and black populations. The CI/CH ratios in Asian populations, including Chinese, Japanese and Korean, were much lower than those in Caucasian and black populations. Dietary, environmental and genetic factors probably play important roles in these differences.

Localization of TIMP-1, TIMP-2, TIMP-3, gelatinase A and gelatinase B in pathological human corneas

PURPOSE

Determine the tissue distribution patterns for tissue inhibitors of metalloproteinases (TIMP-1, TIMP-2, TIMP-3), gelatinase A and gelatinase B in normal and pathologic corneas.

METHODS

Corneas were examined by immunohistochemistry, using antibodies to TIMP-1, TIMP-2, TIMP-3, gelatinase A or gelatinase B.

RESULTS

In normal corneas, TIMP-1 antibody stained the epithelium and endothelium. TIMP-2 and TIMP-3 stained the epithelium, keratocytes and endothelium. Gelatinase A staining was weak and restricted to the epithelial cells. Radial keratotomy scars showed increased staining for TIMP-1 and TIMP-2 around the epithelial cell plug and along the incision. Bullous keratopathy corneas showed TIMP staining patterns similar to normal corneas and increased gelatinase A staining in regions of subepithelial fibrosis. Stromal scars of keratoconus corneas also had increased staining with TIMP-1 and TIMP-2 antibodies. In many keratoconus corneas, the TIMP-3 staining pattern was similar to normal corneas. However, in some keratoconus corneas, when Bowman's layer was missing, the stroma beneath was completely devoid of TIMP-3 antibody staining. No gelatinase B was seen in either the normal or diseased corneas.

CONCLUSION

These data suggest that TIMP-1 and TIMP-2 are important for scar formation and corneal remodeling, since they were found in increased amounts at radial keratotomy incision sites and keratoconus scars. The significance of the focal stromal defects in TIMP-3 staining, associated with absence of Bowman's layer on keratoconus corneas, needs to be elucidated. At the stages of disease examined in this study, gelatinase B may not play a significant role in these pathological processes, since it was not seen in any of the corneas examined.

Subtypes of ischemic stroke. A hospital-based stroke registry in Taiwan (SCAN-IV)

BACKGROUND AND PURPOSE

To better understand the clinical pattern and further elucidate the risk factors and outcome in different subtypes of cerebral infarction (CI) of the Chinese in Taiwan, we analyzed the National Taiwan University Hospital Stroke Registry in 1995 and performed an ethnic comparison with similar data banks.

METHODS

From the National Taiwan University Hospital Stroke Registry in 1995, 676 patients (383 men and 293 women; mean age, 64.9 years; SD, 13.8 years; range, 1 to 98 years) with CI were recruited for this analysis. CI was classified into five subtypes based on clinical manifestations, ultrasonographic studies, and neuroimaging findings: large-artery atherosclerosis, lacunae, cardioembolism, other less common determined causes, and undetermined cause. Vascular risk factors, extracranial carotid artery atherosclerosis, and 30-day case-fatality rates were investigated in each subtype of CI.

RESULTS

Of all CI patients, 17%, 29%, 20%, 6%, and 29% were classified as large-artery atherosclerosis, lacunae, cardioembolism, other determined causes, and undetermined cause subtypes, respectively. The present results were compared with those from eight similar Western stroke registries. The relative incidence of lacunar CI in Chinese patients was more common, but large-artery atherosclerotic CI was less common than in whites. Hypertension was frequently seen in CI patients, especially in those with lacunae (85%) and large-artery atherosclerosis (69%). Patients with cardioembolism had a higher percentage of atrial fibrillation (69%), left ventricular hypertrophy, and ischemic heart disease than the other patients. Patients with large-artery atherosclerosis had more vascular risk factors, such as hypertension, diabetes mellitus, smoking, and carotid stenosis. Cardioembolic patients had higher case-fatality rates than other CI patients. Of the cardioembolic patients, 17.3% and 21.8% died within 30 days and during hospitalization, respectively.

CONCLUSIONS

The proportion of CI subtypes varied in different stroke registries. This may be partly due to applied classification criteria and racial-ethnic differences. Awareness of the risk factors and outcome in each subtype of stroke may afford further insights into the surveillance and treatment of cerebrovascular disease.

[Studies on improving the ability of learning and memories of yangshoudan]

OBJECTIVE

To observe the effects of Yangshoudan(YSD) on the ability of learning and memories in experimental animals.

METHODS

The tests of darkness-avoidance response in normal young mice and rats, aged mice, as well as in model mice with dysmnesia induced by anisodine, model rats with dysmnesia induced by scopolamine hydrobromide and with orientation disturbance induced by pentobarbital sodium.

RESULTS

In normal young mice and rats, the error times in five minutes in learning and memories tests was reduced (P < 0.01-0.05) by YSD, while in dysmnesia groups the error times in five minutes also reduced (P < 0.01-0.05) and the incubation period of memories could be shortened by YSD. In orientation disturbance mice, the averages and percentages of correct response times increased by YSD.

CONCLUSIONS

YSD could improve the memory ability both in normal and dysmnesia which either induced by drugs or due to age. This indicates primarily that YSD has the effects of improving the ability of learning and memories and of antidementia.

Stimulation of locus coeruleus increases arterial pressure in rabbits

AIM

To study the effect of electric and chemical stimulation of locus coeruleus (LC) on arterial pressure and renal sympathetic nerve discharge activity (RSA).

METHODS

Electric stimulation of LC and microinjection of L-glutamate (L-Glu), morphine, and GABA into the LC of rabbits were made. The LC was destructed electrolytically. Arterial pressure and RSA were recorded.

RESULTS

Both electric stimulation (150 microA, 50 Hz) of the LC and microinjection of L-Glu (0.5 mumol) into unilateral LC elicited increases in arterial pressure (13.5 +/- 0.3 vs 19.5 +/- 0.8 kPa, P < 0.01 and 13.8 +/- 0.4 vs 17.5 +/- 0.8 kPa, P < 0.01, respectively) and RSA (by 107 +/- 14%, P < 0.01, and 88 +/- 21%, P < 0.01, respectively). Microinjection of morphine or GABA did not induce any significant changes in the above two parameters. Electrolytic lesion of the LC eliminated the pressor response induced by microinjection of L-Glu.

CONCLUSION

Excitation of LC has a pressor effect in rabbits, but LC is not a crucial nucleus in tonic regulation of blood pressure.

An AU at the first base pair of helix 3 elevates the catalytic activity of hepatitis delta virus ribozymes

A mutational analysis of the helix 3 (H3) region of hepatitis delta virus (HDV) ribozymes disclosed that an AU at the first base pair of H3 elevates the catalytic activity of various cis- and trans-acting HDV ribozymes. A GC to AU substitution at this position of H3, which is located at the junction of three of the four helices of the pseudoknot-like structure model, altered the structure of HDV ribozymes. This substitution in the H3 did not change the independence of the cleavage rate to pH nor the sensitivity to formamide treatment of the ribozymes.

Stroke prevalence in Taiwan. Findings from the 1994 National Health Interview Survey

BACKGROUND AND PURPOSE

Stroke has been the second leading cause of death for all ages in Taiwan since 1983. However, despite the severity of the threat, stroke prevalence in Taiwan has not yet been addressed in a nationwide survey. In this study, the stroke prevalence in Taiwan was investigated using data from the 1994 National Health Interview Survey.

METHODS

This nationwide survey sought to obtain a nationally representative sample of households in Taiwan by using three-stage stratified random sampling with a probability proportional to size. In the first stage, 58 townships were selected, from the 359 townships in Taiwan, according to their administrative structure and level of socioeconomic development. In the second stage, 149 basic administrative regions (tsun or li) were selected from the selected 58 townships. Finally, 3814 households were selected from the 149 selected tsuns or lis. Field interviews were carried out between October 1994 and December 1994. Follow-up interviews with families of stroke patients were made 2 years later.

RESULTS

Of the selected households 3119, or 81.8%, responded. A total of 11925 persons were interviewed, and 71 of them were stroke patients, with a crude point prevalence rate of 5.95 per 1000. The stroke prevalence increased steadily with age, from 0.51 per 1000 in persons aged 35 to 44 years to 113.6 per 1000 in persons aged 85 years or over. There was a weak association with higher stroke prevalence for persons living in eastern Taiwan or those of lower educational level. The overall male/female prevalence ratio was 1.17. The results of follow-up interviews showed a cumulative mortality rate of 25.4% within the 2-year period and an ischemic/hemorrhagic stroke ratio of 1.33 in 35 patients whose stroke type could be validated.

CONCLUSIONS

Age was the most important factor correlating to stroke prevalence. On the basis of this result, planning policies and programs for stroke prevention in Taiwan should give a higher priority to (1) aggressive primary prevention for aged people who are apparently at higher risk of stroke and (2) early reduction of stroke risk factors in younger aged people whose immediate risk of stroke is lower but would increase significantly with age.

Effectiveness of low-dose ASA in prevention of secondary ischemic stroke, the ASA Study Group in Taiwan

This randomized double-blind controlled study was carried out to investigate the effect of 100 mg acetylsalicylic acid (ASA) per day on the secondary prevention of ischemic stroke. Patients who suffered a first ischemic stroke from 13 participating hospitals were enrolled. They were independent or only partially dependent in activities of daily living and all had received brain CT for diagnosis. Eligible patients were randomly allocated to the 100 mg ASA or the nicametate citrate (a vasodilator) groups, and trial medications were started within three to six weeks after the onset of stroke. The primary end point was cerebral reinfarction, and intracranial hemorrhage was classified as an adverse event. Four hundred and sixty-six patients participated in this study; and 222 cases (136 males and 86 females) were allocated to the ASA group while 244 cases (150 males and 94 females) were assigned to the nicametate group. No significant difference in baseline characteristics between the two groups was observed. Cerebral reinfarction developed 6.3% (14/222) in the ASA group and 11.9% (29/244) in the nicametate group. According to the Cox's proportional hazards model, the estimated risk ratio (ASA group vs. nicametate group) was 0.538, with a 95% confidence interval of 0.284-1.019. The result was of borderline statistical significance. The risk for cerebral reinfarction was reduced by almost 50% among those who took 100 mg ASA versus those who took nicametate.

[Electrophysiological study of the relationship between rostral ventrolateral medulla and locus coeruleus of rabbits]

The electrophysiological characteristics of locus coeruleus (LC) neurons and the projection from the rostral ventrolateral medulla (RVLM) to the LC were investigated on 18 rabbits, which were lightly anesthetized, decerebelated, paralyzed and artificially ventilated. 93 of the 108 recorded LC neurons are firing spontaneously at about 5.1 Hz, while the remaining are silent but could be activated by pinching. 64 (59.2%) of the LC neurons manifested excitatory response to brushing and 93 (86.1%) to pinching. Of the 108 LC neurons, 85 (78.7%) neurons could be activated orthodromically by ipsilateral RVLM stimulation with a latency of 21.6 +/- 6.9 ms, among which 67 neurons showed excitatory response. 35 of the 123 recorded RVLM neurons responded antidromically to ipsilateral LC stimulation with a latency of 19.2 +/- 8.2 ms. These results suggest that there may exist a direct excitatory pathway from RVLM to LC.

[Activation of locus coeruleus inhibits vagal inputs in nucleus tractus solitarius]

On pentobarbital anesthetized rabbits, a three-wavelet compound potential to cervical vagal afferent stimulation was recorded in ipsilateral nucleus tractus solitarius (NTS). The latency of the three wavelets (P1, P2 and P3) was 6.8 +/- 0.6 ms (P1), 25.8 +/- 4.2 ms (P2) and 89.1 +/- 2.7 ms (P3) respectively, which might represent postsynaptic activity of different kinds of vagal afferent fibers. Microinjection of glutamate into ipsilateral locus coeruleus (LC) decreased the amplitude of P2 and P3 significantly. Electrical stimulation of LC could activate 111 units in ipsilateral NTS with a mean latency of 6.3 +/- 1.4 ms. Of the 169 units in the NTS to vagal afferent stimulation, 90 units also responded to LC stimulation. 39 (43.3%) of the ninety, units shows similar response to both stimuli, while the rest show different response. Of the 25 units which showed excitatory response to both LC and vagal stimulation, but when LC stimulation was followed by vagus stimulation, the latter's response was either markedly suppressed (14 units) or completely inhibited (11 units). These results showed that activation of LC exerts an inhibitory effect on the responses of the NTS to vagal afferent stimulation.

Basement membrane abnormalities in human eyes with diabetic retinopathy

Vascular and parenchymal basement membranes (BMs) are thickened in diabetes, but alterations in individual BM components in diabetic eyes, especially in diabetic retinopathy (DR), are obscure. To identify abnormalities in the distribution of specific constituents, we analyzed cryostat sections of human eyes obtained at autopsy (seven normal, five diabetic without DR, and 13 diabetic with DR) by immunofluorescence with antibodies to 30 BM and extracellular matrix components. In non-DR eyes, no qualitative changes of ocular BM components were seen. In some DR corneas, epithelial BM was stained discontinuously for laminin-1, entactin/nidogen, and alpha3-alpha4 Type IV collagen, in contrast to non-DR corneas. Major BM alterations were found in DR retinas compared to normals and non-DR diabetics. The inner limiting membrane (retinal BM) of DR eyes had accumulations of fibronectin (including cellular) and Types I, III, IV (alpha1-alpha2), and V collagen. The BM zone of new retinal blood vessels in neovascularized areas accumulated tenascin and Type XII collagen, whereas normal, diabetic, and adjacent DR retinas showed only weak and irregular staining. In preretinal membranes, perlecan, bamacan, and Types VI, VIII, XII, and XIV collagen were newly identified. Diabetic BM thickening appears to involve qualitative alterations of specific BM markers at an advanced disease stage, with the appearance of DR.

The importance of the helix 2 region for the cis-cleaving and trans-cleaving activities of hepatitis delta virus ribozymes

The sequence, secondary structure, and size requirements of the helix 2 region (H2) of a cis-acting hepatitis delta virus ribozyme Rz 1 were examined in this study. Mutational analysis was performed, and the cleavage rate of each H2 mutant of Rz 1 was assayed. We found that H2 could be elongated to twice its original size without affecting ribozyme folding while the shortening of H2 by one base pair severely decreased autolytic activity. In addition, the maintenance of the Watson-Crick base-pairing interactions of the last base pair of H2 (A16U58) was not critical for cis-cleavage reaction. Nevertheless, mutants with an AA, an AG, an AC, or a GG pair at the bottom of H2 were less active, and the sequence of the H2/H3 interface might affect the stability of the catalytic core. The negative effects on ribozyme folding, such as the destabilization of H2, the unfavorable sequences at the last base pair of H2 as well as the disruption of the continuity of H2 and H3, could be compensated for by elongating the H2 region of the corresponding mutants. The extension of H2 may alter the conformation of ribozyme molecules; in addition, it stabilized the catalytic core and enhanced the resistance to formamide. Finally, for a trans-acting ribozyme and its substrate that require the formation of H1, H2, and H4 to reconstitute the autocatalytic domain of HDV RNA, the extension of H2 stabilized the substrate/ribozyme complex and speeded up the cleavage rate but hindered the product release process.

[Medullary mechanism of the inhibition on renal sympathetic efferent activities by stimulation of the cervical vagal afferent nerve in rabbits]

Experiments were performed on 63 rabbits anesthetized with pentobarbital, paralyzed with gallamine triethiodide and ventiled artifically. Ipsilateral renal sympathetic nerve discharge (RSND), unit discharges of rostral ventrolateral medulla (RVL), caudal ventrolateral medulla (CVL) and blood pressure (BP) were recorded. The sympatho-inhibitory response were evoked by stimulation of the central end of vagal nerve (CVN) (731/788 exp.). The inhibitory duration is 3.6 +/- 0.185 s. The responses vary with the functional state of the CNS. The RSND inhibitory duration could be shortened or prolonged, depending on the excitatory background of RSND or the basal sympathetic tonic activity. The results indicate that CVN-induced inhibitory of RSND may be mediated, at least partly, by excitation of NTS and CVL, which results, in turn, in depressing RVL and final reduction of sympathetic efferent activity.

[Kindling of rat epilepsy by intracerebroventricular injection of norfloxacin and ultrastructural changes of brain]

AIM

To study the toxic effects of norfloxacin (Nor) on EEG and ultrastructure of the brain.

METHODS

EEG was recorded in the sensorimotor area of rat cortex after Nor 150 and 300 micrograms.kg-1 were injected into the right ventricle of the brain.

RESULTS

Spike waves occurred, first at the ipsilateral side and then bilaterally. The seizure spike appeared at 168 +/- 129, 51 +/- 35 s, and 276 +/- 138, 118 +/- 65 s in the right and left cerebral cortices in 150 and 300 micrograms.kg-1 groups, respectively. The wave forms were variable, the wave amplitude and frequency increased gradually, accompanied with limb twitching. Neuron degeneration was seen in both cerebral hemispheres, hippocampus, and cerebellum 120 min after the i.c.v. of Nor 300 micrograms.kg-1: myeloid degeneration of Golgi complex, rough endoplasmic reticulum, and neuropils; swelling of cytoplasm; dissolution of nuclears and chromatin; necrosis of gliocytes and the appearance of changes in both the light and dark neurons, especially the dark ones.

CONCLUSION

Rat brain was widely damaged after the kindling by Nor.

[The coherence between the frontal-parietal cortex and cardiac sympathetic nerve activity in cats]

Experiments were performed on 86 cats anesthetized with chloralose, paralyzed with gallamine triethiodide and ventilated artificially. Autospectral and coherence analysis revealed that the frontal-parietal cortex activity (EEG) and cardiac sympathetic nerve discharge (SND) were remarkably correlated in 33/44 cats. SND lagged EEG by 50 +/- 20 ms with a cross-correlation value of 0.4 +/- 0.1. Coherence value was 0.25 +/- 0.05, indicating a statistically significant relationship between the two signals. Midbrain transection at stereotaxic plane A3 preferentially decreased SND power at frequencies 3-4.2 Hz, accompanied by a fall in mean blood pressure (5.47 +/- 0.13 kPa). The coherence of SND to EEG was eliminated after decerebration. However, the total power in EEG was not significantly affected. The SND rhythm and blood pressure returned nearly to control level within 1 h after decerebration. The effects of midbrain transection were significantly attenuated by prior minor lesions of the lateral hypothalamus or medial thalamus. These results suggest that the forebrain is responsible significantly for a component of sympathetic tone in anesthetic cats. The integrity of diencephalon is required for the participation of forebrain in setting the level of basal SND. Reduction in SND following decerebration was due in part to interruption of the descending influence from diencephalon and brain stem sympathetic rhythm generators are involved in compensating for the loss of the forebrain dependent component of SND.

In hypercholesterolemia, lower peripheral monocyte count is unique among the major predictors of atherosclerosis

Many studies have shown that enhanced monocyte adherence is an important factor in the initiation of atherosclerosis. Because the relationships between circulating monocyte count and atherosclerosis or its major predictors have received little attention, we conducted this study with the aim of clarifying these relationships. The study included 409 men and women who underwent a carotid artery duplex study and white blood cell analysis (Sysmex Cell Counter) during a 2-day health check at our hospital in 1994. We found no correlation between preexisting carotid atherosclerosis and monocyte count. After adjustment for age and sex, hypercholesterolemia, among the major predictors of atherosclerosis, showed a unique correlation with both lower monocyte count and percentage (P < .001, P < .0001, respectively), whereas smoking was correlated with a higher monocyte count (P < .001). There was a slight but nonsignificant increase in monocyte count in hypertension, diabetes, and hypertriglyceridemia. Our results imply that: (1) hypercholesterolemia has a strong, peripheral monocyte-reducing effect, probably due to direct enhancement of monocyte adhesion to the endothelium, which subsequently initiates the atherosclerotic process, and (2) the mechanisms of other predictor(s)-induced atherosclerosis may be quite different from that of hypercholesterolemia. Another possible explanation for the inverse correlation between monocyte count and serum cholesterol level is that decreased monocyte levels might lead to hypercholesterolemia because of decreased uptake of cholesterol from the plasma by less monocyte-derived macrophages. The reasons why preexisting carotid atherosclerosis did not correlate with monocyte count are also discussed.

Impact of alcohol consumption and cigarette smoking on stroke among the elderly in Taiwan

BACKGROUND AND PURPOSE

We investigated the influence of alcohol consumption and cigarette smoking on all types of stroke and cerebral infarction, in particular among a representative sample of elderly residents in Taiwan.

METHODS

This study was a component of a nationwide survey of health and living status of residents aged 65 years or older in Taiwan in which subjects received detailed physical, neurological, and laboratory examinations. Inquiries were made about medical history, and information on the amount and duration of drinking and smoking was obtained. Diagnoses of stroke were made according to the results of brain computed tomography at the onset of disease or were based on criteria established by the World Health Organization.

RESULTS

Of the 2600 subjects, there were 155 elderly persons with stroke (prevalence, 6%). Excessive drinking of more than 367.6 g/wk of alcohol was associated with a high prevalence of cerebral infarction. Consumption of < or = 367.5 g/wk of alcohol did not have an influence on stroke prevalence. The relationship between duration of alcohol drinking and stroke was equivocal. More than 30 pack-years of cigarette smoking was a significant risk factor for all types of stroke and cerebral infarction in particular. Using multiple logistic regression to control for possible confounders, it was found that smoking was an independent risk factors for all stroke and was of borderline significance for cerebral infarction. Although excessive drinking was a significant risk factor for cerebral infarction in univariate analysis, this effect was lost after adjustment for other confounders.

CONCLUSIONS

Cigarette smoking was a more important risk factor for stroke and cerebral infarction than excessive drinking of alcohol.

Role of transesophageal echocardiography in the diagnostic assessment of cardiac sources of embolism in patients with acute ischemic stroke

To evaluate the role of transesophageal echocardiography (TEE) in the diagnostic assessment of cardiac sources of embolism in acute ischemic stroke, 94 consecutive patients (44 men and 50 women, aged 22-82 years) with acute ischemic stroke were prospectively studied. Of these, 34 patients had clinical evidence of heart disease. Both transthoracic and transesophageal echocardiograms were recorded on the same day for each patient. Transthoracic echocardiography (TTE) identified a possible cardiac source of embolism in 2 patients (6%) with and in 3 (5%) without clinical heart disease. TEE identified a possible cardiac source of embolism in 21 patients (62%) with and in 18 (30%) without clinical heart disease. TEE was superior to TTE for the detection of a cardiac source of embolism in patients with acute ischemic stroke (41 vs. 5%, p < 0.001). Factors significantly associated with a greater likelihood of such cardiac sources of embolism included left atrial enlargement, atrial fibrillation and a younger age. The yield of TEE in identifying a possible cardiac source of embolism was higher in patients with clinical evidence of heart disease than in those without.

Effects of hyperlipidemia on the vascular reactivity in the Wistar-Kyoto and spontaneously hypertensive rats

We studied the effects of hyperlipidemia on the vascular responsiveness in aortas isolated from control rats and rats receiving a high cholesterol-high fat (HC-HF) diet (1% cholesterol and 20% olive oil). The total plasma cholesterol, very low density lipoprotein (VLDL)-, low density lipoprotein (LDL)-cholesterol, VLDL-, LDL-, high density lipoprotein (HDL)-triglyceride levels were markedly elevated in HC-HF chow fed Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR) compared to the respective normal chow fed control rats. The increase in plasma cholesterol and triglyceride levels were time-dependent. Higher levels of cholesterol and triglyceride were observed in SHR compared to WKY. In the aortic arches and abdominal aortas obtained from the SHR and WKY fed the HC-HF chow for 8 week, evoked intimal lesions were more pronounced than those noted after 4 weeks of HC-HF chow fed. The aortic arches of SHR and WKY were significantly more affected by the intimal lesion (surface area damage and fatty streak formation) than the abdominal aortas of the respective rat strain. The damage of surface area and thickness of fatty streaks were significantly augmented with the period the rats were fed the HC-HF diet. In the denuded aortic arches of the WKY and of rats receiving HC-HF diet for 8 weeks, significantly attenuated ED50 values and augmented maximal responses for phenylephrine (0.01-30 microM)-induced contraction were obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of the brain stem in generating the 2- to 6-Hz oscillation in sympathetic nerve discharge

We tested the hypothesis that brain stem circuits normally generate a 2- to 6-Hz oscillation in sympathetic nerve discharge (SND). Experiments were performed on baroreceptor-denervated decerebrate cats and urethan-anesthetized rats in which renal or splanchnic SND was recorded along with field potentials (population activity) from sites in the rostral ventrolateral medulla, medullary raphe, or medullary lateral tegmental field. Our major findings were as follows. 1) Population activity recorded from the three medullary regions contained a 2- to 6-Hz oscillation. 2) The 2- to 6-Hz oscillation in population activity recorded from some medullary sites was correlated to that in SND. Peak coherence in the 2- to 6-Hz band approached a value of 1 in some cases. 3) Whereas cervical spinal cord transection abolished or markedly reduced SND, the 2- to 6-Hz oscillation in medullary activity was essentially unchanged. These results support the view that the 2- to 6-Hz oscillation in SND can be generated in the brain stem of cats and rats.

Regional mapping of the gene for familial Mediterranean fever on human chromosome 16p13

Familial Mediterranean fever (FMF) is an autosomal recessively inherited inflammatory disorder characterized by recurrent short episodes of fever, peritonitis, arthritis, and pleuritis. Recently, linkage was demonstrated between FMF and the VNTR probes 3'HVR and 5'HVR of the alpha-globin complex at 16p13.3 (theta = 0.06-0.10, Lodmax = 9.76-14.47) and the insertion/deletion polymorphism detected by the probe CMM65 of D16S84 (theta = 0.04, Lodmax = 9.17). We have now mapped the FMF gene between the two flanking markers D16S283/D16S291 (theta = 0.038) and D16S80 (theta = 0.159). The proximity of the microsatellite markers in D16S283 and D16S291 to the FMF gene allows preclinical diagnosis in most pedigrees with affected individuals.

Combined use of aspirin and heparin inhibits in vivo acute carotid thrombosis

BACKGROUND AND PURPOSE

Carotid atherosclerotic thrombosis is an important cause of ischemic stroke in Western countries. The therapeutic efficacy of either aspirin or heparin alone in this setting is still controversial. Recently we developed a simple model, the "clamp" method, to induce acute carotid mural thrombosis in vivo in guinea pigs. In this study, we used this model to evaluate the antithrombotic effects of aspirin, heparin, and their combination.

METHODS

Sixty-four male guinea pigs were divided equally into control, aspirin, heparin, and combined groups. Physiological saline, aspirin (5 mg/kg body wt), heparin (200 units/kg body wt), or a combination of aspirin and heparin, respectively, was injected via the jugular vein before the use of the clamp method. Thirty minutes after the injection of saline or drug(s), Péan's forceps was used to clamp the carotid artery at a tangent angle for 3 minutes. One hour later, the carotid artery was resected and prepared for observation under a scanning electron microscope or light microscope to evaluate the degree of mural thrombosis.

RESULTS

The results showed that the combination of aspirin and heparin had an excellent effect in inhibiting in vivo acute carotid thrombosis (p < 0.001) and was significantly better than the effect of aspirin alone (p < 0.01) or heparin alone (p < 0.01).

CONCLUSIONS

Our study clearly demonstrated that the combined use of aspirin and heparin produced a much better antithrombotic effect than either agent alone at sites of carotid endothelial injury when given before the injury. This combined regimen may be useful clinically in acute carotid thrombosis secondary to carotid diseases or carotid endarterectomy.

The 10-Hz sympathetic rhythm is dependent on raphe and rostral ventrolateral medullary neurons

We studied the effects of brain stem and spinal lesions on the 10-Hz rhythms in left and right inferior cardiac sympathetic nerve discharge (SND) of baroreceptor-denervated, decerebrate cats. Unilateral medullary lesions [parasagittal section 1.5 mm lateral to midline, radiofrequency lesion of the rostral ventrolateral medulla (RVLM), or chemical inactivation (muscimol) of the RVLM] dramatically reduced the 10-Hz rhythmic discharges in the two nerves. Power in the 10-Hz band of ipsilateral inferior cardiac SND was reduced more than that in contralateral SND. In contrast, bilateral parasagittal medullary sections or microinjection of muscimol into the medullary raphe uniformly reduced the 10-Hz rhythmic discharges of both nerves. Unlike unilateral medullary lesions, rostral pontine or cervical spinal hemisection reduced the 10-Hz discharges of only the ipsilateral inferior cardiac nerve. The chemical inactivation experiments demonstrate that the 10-Hz rhythm in SND is dependent on medullary raphe and RVLM neurons. Moreover the experiments with unilateral lesions demonstrate a mutually facilitatory interaction of medullary circuits that are responsible for the 10-Hz rhythmic discharges in sympathetic nerves located on opposite sides of the body.

Mutagenesis analysis of the self-cleavage domain of hepatitis delta virus antigenomic RNA

To determine the sequence requirements and structural features of the self-cleavage domain of hepatitis delta virus (HDV) antigenomic RNA, we constructed a series of mutants and measured the rate constant of the cleavage reaction for each. The self-cleavage activity of HDV RNA of antigenomic sense was found to reside in a region of less than 90 nucleotides in length. The catalytic domain contained a long complementary sequence which could be deleted to half of its original size. Moreover, this region could be replaced by other sequences as long as they could fold into a stem-and-loop structure. The catalytic domain also required a 6-basepair helix adjacent to the cleaving point for activity. The structural features of these two base-pairing regions are quite similar to those of the HDV genomic self-cleavage domain. The cleavage site as well as the the hinge region (the sequence between the two stems) requires specific sequences for activity.

Dissociation of inhibitory effects of low-dose ASA on thromboxane production and platelet aggregation in ischemic stroke patients

Acetylsalicylic acid (ASA) inhibits thromboxane production and hence platelet aggregation. However, individual variations in platelet aggregability and serum thromboxane B2 (TxB2) concentration after a low dose of ASA (40 mg/day) have been reported. To clarify this issue, we studied plasma thromboxane levels and platelet aggregation in 43 ischemic stroke patients. Of the 22 patients who received 100 mg of ASA daily, dissociation between inhibitory effects of ASA on the plasma TxB2 level and threshold concentrations of adenosine diphosphate was found in three cases after one month of drug administration, and in three cases after six, 12 and 18 months of ASA therapy. This dissociation also developed in two patients after one month and six months, respectively, of treatment in the 21 patients who received 300 mg of ASA daily. The dissociation between the inhibitory effects on plasma TxB2 and the circulating platelet aggregate ratio was found in two cases after taking medication for one month, and in four cases after six, 12, 18 and 24 months of therapy in the 100 mg ASA group. In the 300 mg ASA group, dissociation was noted in two cases after one month of medication, and in two cases after six and 12 months of medication. In these patients, although their TxB2 levels were inhibited to almost unmeasurable levels, platelet aggregation was still not inhibited. This ASA inhibitory dissociation phenomenon on platelet function may be due to the low dose of ASA, individual differences in platelet function in response to ASA therapy, or factors other than those involved in the cyclooxygenase system.

Forced oscillations in sympathetic nerve discharge

Periodic electrical stimulation of the medullary raphe or lateral tegmental field in baroreceptor-denervated cats was used to force the central systems responsible for the 10-Hz and 2- to 6-Hz rhythms in post-ganglionic sympathetic nerve discharge (SND). The 10-Hz rhythm in SND could be entrained either to the frequency of medullary stimulation or to harmonics of the stimulus frequency. The harmonic of the stimulus frequency to which the 10-Hz rhythm was entrained in one postganglionic nerve could be different from that in another nerve. On this basis, we propose that the circuits responsible for the 10-Hz rhythms in SND may be modeled as a system of coupled nonlinear oscillators, each of which either influences one postganglionic nerve or nonuniformly affects different postganglionic nerves. The relatively wide band 2- to 6-Hz component in SND could be forced into a stable oscillatory state by medullary stimulation at frequencies between 3 and 5 Hz. This observation is consistent with the view that the 2- to 6-Hz component reflects the complex behavior of a nonlinear oscillator rather than the output of a physiological noise generator.

Two polyhydroxylated steroids from the Chinese soft coral Sinularia microclavata

Two polyhydroxylated steroids have been isolated from the South China Sea soft coral Sinularia microclavata, and their structures were established as 24-methylenecholestane-1 alpha,3 beta,5 alpha,6 beta-tetrol and 1 alpha,3 beta,5 alpha-trihydroxy-24-methylenecholestan-6-one from spectral evidence and from comparison with two reference compounds, numersterol A and 24-methylenecholestane-1 alpha,3 beta,5 alpha,6 beta, 25-pentol, which were isolated from the soft corals, Simularia numerosa and Sarcophyton glaucum, respectively.

Image sensor operating in a persistence-integration mode

We propose a novel solid-state image sensor based on a new charge integration concept. This sensor is suitable for imaging low-speed or static objects at low light levels. A model of the sensor as well as the experimental results of a single pixel device is presented. The dynamic range is approximately 110 dB. The linearity is gamma ? 0.71 at low-light levels. The signal gain of the device can automatically increase with a decrease of incident light power.

Electroacupuncture in rats: evidence for naloxone and naltrexone potentiation of analgesia

Low frequency electroacupuncture (EA) analgesia has been thought to be mediated by endogenous opioids. Among other lines of evidence, it has been reported that EA stimulation delivered at 2 and 2-15 Hz in rats could be blocked or partially antagonized by naloxone (NAL) and naltrexone (NTX). In contrast, experiments in one of our laboratories (D.J.M.) showed that NAL did not inhibit 2 Hz, and even potentiated 125 Hz EA analgesia. In an attempt to resolve these discrepancies, we conducted joint experiments in the U.S.A. and in China using the methods which previously yielded NAL reversibility of EA analgesia. In no experiment did opiate antagonists block or reduce EA analgesia. On the contrary, we found that, in most experiments, NAL and NTX potentiated 2 and 2-15 Hz EA analgesia respectively. The potentiation occurred independently of laboratory methods, geographic location of the experiment, strain (Chinese or American), tail temperature, sex, and weight of rats. This potentiation suggests the existence of an opioid anti-analgesic system or that NAL and NTX acquired analgesic properties following EA. These results indicate that EA analgesia in rats is a variable phenomenon even when laboratory methods are rigorously replicated. The EA stimulation may activate multiple conflicting neural circuits which interact and ultimately modulate the analgesic outcome.

The strength and periodicity of D. melanogaster circadian rhythms are differentially affected by alterations in period gene expression

The per gene of D. melanogaster influences or participates in the generation of biological rhythms. Previous experiments have identified the head as the location from which per exerts its effect on circadian rhythms. To localize further this region and to examine the effects of altered levels and altered spatial expression patterns of the per gene on circadian rhythms of locomotor activity, we have characterized transformed lines containing per gene constructs missing substantial cis-acting regulatory information. The data suggest that wild-type levels of per gene expression are necessary in only a small fraction of the nervous system for near wild-type periods, whereas a larger fraction of per-expressing cells in the brain contributes to the strength of the circadian rhythms.

A 5-year surveillance of sensitivity in vivo of Plasmodium falciparum to pyronaridine/sulfadoxine/pyrimethamine in Diaoluo area, Hainan Province

The surveillance of sensitivity of P. falciparum to pyronaridine/sulfadoxine/pyrimethamine has been carried out in Diaoluo area in Hainan Province where chloroquine-resistant falciparum malaria is endemic, covering an area of 406 square kilometers, with a population of 3745 in 1986. From 1986 all outpatients diagnosed as falciparum malaria were administered with PND/S/P as the only antimalarial. In vivo sensitivity of P. falciparum was measured in some patients who were treated in hospital. It was demonstrated that P. falciparum in the Diaoluo area has retained its sensitivity to a single oral dose of PND/S/P of 500/1,000/50 mg with 100% cure rate for at least 5 years.

Comparison of in vitro platelet aggregation and its inhibition by three antithrombotic drugs between human and guinea pig

Platelets of guinea pigs are frequently used to evaluate the effect of new antiplatelet agents. Although several studies have compared the platelet aggregation between humans and guinea pigs, but so far the information is still limited. In this study, we compare the inhibitory effect of aspirin, dipyridamole and pentoxifylline on the platelet aggregation induced by adenosine diphosphate (ADP), collagen, arachidonic acid and thrombin between humans and guinea pigs. The results for humans and guinea pigs were compared and analysed by two-way analysis of variance (ANOVA). Our results showed: 1. The trends wherein these three drugs suppressed collagen-induced platelet aggregation was very similar in humans and guinea pigs. 2. In ADP-induced aggregation, the trend of inhibition caused by the three drugs was also similar in humans and guinea pigs except that a difference in platelet disaggregation at a late phase of platelet aggregation was noted. 3. In arachidonic acid- and thrombin-induced aggregations, the trend of inhibition caused by the three drugs was somewhat different in humans and guinea pigs. 4. Considering all activators as a whole, it was found that the status of platelet disaggregation at the late phase of platelet aggregation was different in humans and guinea pigs. Therefore, we concluded that: 1. Collagen was the most appropriate platelet activator when we used platelets of guinea pigs to study the effect of new antiplatelet agents. 2. When platelets of guinea pigs were used to study platelet aggregation, no matter which activator was used, we should avoid using the late phase of aggregation as the control index for comparison, because the results thus obtained might not be applicable to human platelets.

[Interaction of abdominal vagus and greater splanchnic nerve activities in the nucleus tractus solitarius of the rabbit]

Experiments were performed on 67 rabbits. Effects of stimulation of the central ends of abdominal vagus and greater splanchnic nerve on arterial blood pressure before and after destruction of nucleus tractus solitarius (NTS) and the unit discharges in the NTS before destruction were observed. As a result, we suggest that both the afferents coming from the abdominal vagus and greater splanchnic nerve not only converge on NTS neurons but also interact with each other. Subthreshold stimulation elicited from one of the afferent fibers suppresses the arterial blood pressure responses caused by the other afferent. Similarly, background stimulation elicited from one afferent can suppress the NTS unit discharges caused by the other afferent. It is much easier for abdominal vagal afferent to inhibit the NTS unit discharges and the arterial blood pressure changes elicited by stimulation of the splanchnic nerve. A possible mechanism of such relationship was discussed.