Tracing developing pathways in the brain: a comparison of carbocyanine dyes and cholera toxin b subunit

The present study examined the efficiency of fluorescent carbocyanine dye 1,1'-dioctadecyl-3,3,3',3'-tetramethylinodocarbocyanine perchlorate and cholera toxin B subunit in tracing the crossed tectal projection to the nucleus rotundus of the thalamus (tectorotundal pathways) of paraformaldehyde-fixed and living chick embryos. The tracers were injected into the optic tectum under three experimental conditions (carbocyanine postfix, carbocyanine in vivo, and cholera toxin B subunit in vivo) and the anterograde transport of the nucleus rotundus was monitored and compared. In the carbocyanine postfix method, small crystals of carbocyanine dye were inserted into the tectum of paraformaldehyde-fixed embryos. A 6-month post-insertion period was required to label the crossed tectorotundal pathway. Results showed that tectal neurons did not begin to innervate the ipsilateral nucleus rotundus until embryonic day 9 and the contralateral nucleus rotundus until embryonic day 17. This slow progression of labeling through the crossed tectal projection resulted in significant contrast of the labeling between the ipsilateral and contralateral nuclei rotundus. In the carbocyanine in vivo method, a small volume of carbocyanine dye solution was injected into the tectum of living embryos. A 8- to 12-h survival period was sufficient enough to label the tectorotundal pathway. By embryonic day 8, the labeled axons terminated in the ipsilateral nucleus rotundus and the crossed tectorotundal projection was first detected by embryonic day 10. Similarly, in the cholera toxin B subunit in vivo method, a small volume of cholera toxin B subunit solution was injected into the tectum of living embryos. After a 6- to 10-h survival period, heavily labeled axons were found to innervate bilaterally the nucleus rotundus by embryonic day 8. This appeared to be the earliest schedule for detecting the crossed tectorotundal projection, compared with that of both the postfix and in vivo methods of carbocyanine dye. Based on the differences in the detectability of the crossed tectorotundal projection between the postfix and in vivo methods, the present data suggest that the former method is of limited purpose for labeling tectal collaterals during embryogenesis. Moreover, given the rapid transport rate and absence of photobleaching, which is often seen when using carbocyanine dye, the cholera toxin B subunit in vivo method appears to be the tracer of choice for investigating embryonic pathways.

Reaming bone grafting to treat tibial shaft aseptic nonunion after plating

OBJECTIVE

To investigate the effects of using intramedullary reaming to provide cancellous bone graft, and reamed intramedullary nail stabilisation to provide fragment stability on treating tibial shaft aseptic nonunions after plating.

METHODS

31 consecutive patients with tibial shaft aseptic nonunions after plating were prospectively treated. Indications for this technique included a tibial shaft nonunion with an inserted plate, a fracture level fit for traditional or locked nail stabilisation, absence of suspected infection and segmental bony defect at the time, and shortening of less than 2 cm. The plate was removed and the marrow cavity was reamed as widely as possible. A stable unlocked or locked intramedullary nail was then inserted. No extra cancellous bone graft was supplemented.

RESULTS

28 patients were followed up for a median period of 2.2 years (range, 1.0-5.2 years). All patients achieved solid union. The median union period was 4.5 months (range, 3.0-7.5 months). There were no significant complications.

CONCLUSION

When reamed intramedullary nails are used to treat tibial shaft aseptic nonunions after plating, supplemented cancellous bone grafting can be spared. Despite the technique being simplified, the success rate is high. We therefore recommend its wide use to treat all suitable cases.

Outbreak of salmonellosis in a zoologic collection of lorikeets and lories (Trichoglossus, Lorius, and Eos spp.)

During August 2001, a syndrome characterized by acute lethargy and dyspnea was observed in a population of 45 lorikeets and lories in an open-air zoologic exhibit. The first death occurred on August 10, and within the next 12 days, nine more birds died (22% mortality rate). Hepatomegaly, reddening and congestion of the lungs, and injection of the serosal surface of the intestines were the common gross findings. Histologic changes, including fibrinonecrotic hepatitis and splenitis, bacterial emboli (liver, spleen, lung, kidney, proventriculus), pulmonary congestion and hemorrhage, and enteritis, were indicative of an acute, overwhelming bacterial septicemia. Salmonella typhimurium, with the same antibiogram, was isolated from four birds. Several birds had attacked and killed a snake on July 24, and Salmonella serogroup B (untypeable) was isolated from intestine and kidney samples of a garter snake caught in the open-air exhibit on August 28. Salmonella was also isolated from environmental samples of the exhibit but not from food preparation areas. After antimicrobial therapy, Salmonella spp. was not isolated from the surviving birds. The source of Salmonella in this outbreak remains unknown, but infection either directly or indirectly from snakes in the exhibit is possible. Contact between captive psittacine populations and reptiles should be avoided to prevent the risk of salmonellosis.

Existence of gene 5 indicates close genomic relationship of Turkey coronavirus to infectious bronchitis virus

A segment of genomic RNA extending from the 3'-end of the membrane (M) protein gene to the 5'-end of the nucleocapsid (N) protein gene of Turkey coronavirus (TCV) was amplified by reverse transcription-polymerase chain reaction (RT-PCR). The primers were derived from the corresponding sequences of Infectious bronchitis virus (IBV). The PCR products were cloned and sequenced and their nucleic acid structure and similarity to the published sequences of IBV were analyzed. Gene 5 containing two overlapping open reading frames (ORFs), 5a and 5b, was localized between M and N genes of TCV. The overall nucleotide sequences of the amplified regions from TCV isolates shared 88.4% to 91.8% similarity to the corresponding region of IBV strains. The consensus transcription-associated sequence of IBV, CTTAACAA, was highly conserved in the TCV genome with regard to nucleotide sequence and location in terms of the initiation codons of the genes 5 and N. The similarities between the predicted amino acid sequences of ORFs 5a and 5b of TCV isolates and the homologous genes of IBV strains were 85.4% to 94.0%. The results indicate the existence of gene 5 in the genome of TCV and a close relatedness of the TCV gene 5 to the IBV gene 5 in location and nucleotide sequence.

Left cervical aortic arch with aneurysm and obstruction: three-dimensional computed tomographic angiography and magnetic resonance angiographic appearance

Cervical arch is a rare congenital anomaly presumed to result from persistence of the third aortic arch and regression of the normal fourth arch. Rather rare is cervical aortic arch associated with aneurysm and obstruction, with eight known cases reported. Definitive diagnosis with a noninvasive imaging modality is desirable and very important to prevent the need for disaster intervention. We present two cases of a pulsatile mass in the left supraclavicular region. Three-dimensional computed tomographic angiography and magnetic resonance angiography clearly showed a left-sided cervical aortic arch (Haughton type D) with arch aneurysm and coarctation (pseudocoarctation).

Brain function and cognition in a community sample of elderly Latinos

BACKGROUND

Previous studies using PET to measure cerebral glucose metabolism in AD have found metabolic reductions in the temporoparietal and posterior cingulate cortices in individuals with dementia and those at risk of developing it. This study was designed to extend this finding to individuals selected from a population-based cohort of Mexican Americans with a wide spectrum of cognitive ability.

METHODS

A group of 93 individuals was selected from the Sacramento Area Latino Study on Aging, and subjects were categorized into four groups of increasing levels of cognitive impairment: normal, memory impaired, cognitively impaired but not demented (CIND), and demented. PET was performed with the tracer [(18)F]-fluorodeoxyglucose, and data were analyzed with both statistical parametric mapping and an atrophy-corrected volume of interest approach.

RESULTS

Individuals with dementia had metabolic reductions that were most robust in the posterior cingulate cortex, whereas CIND subjects had less statistically robust reductions in the posterior cingulate cortex. Cingulate hypometabolism increased the risk of dementia and was a significant risk factor for dementia in logistic regression models that also incorporated MR measures of hippocampal volume and white matter hyperintensities.

CONCLUSION

Posterior cingulate cortical hypometabolism is clearly detected in individuals with dementia who are selected from a population with lower education and a high prevalence of cerebrovascular risk factors, supporting the generalizability of this finding. These metabolic reductions occur prior to the onset of dementia but only in those persons with relatively advanced symptoms.

Brain structure and cognition in a community sample of elderly Latinos

BACKGROUND

Previous studies have found that hippocampal atrophy and white matter hyperintensities (WMH) on MRI are linked to cognitive impairment and dementia. The authors measured these variables in a population-based cohort of older Mexican Americans with a wide spectrum of cognitive ability, ranging from normal cognition to dementia.

OBJECTIVE

To investigate whether these structural brain changes were seen in individuals prior to the development of dementia and how these changes were related to the presence of dementia.

METHODS

A sample of 122 subjects was selected from the Sacramento Area Latino Study on Aging, and subjects were categorized into four groups of increasing levels of cognitive impairment: normal, memory impaired (MI), cognitively impaired but not demented (CIND), and demented. Hippocampal volume was quantified using a region of interest approach. WMH was rated on a semiquantitative scale as the percent of total volume of white matter.

RESULTS

Hippocampal volume was significantly reduced in CIND and demented individuals, and WMH were significantly increased in demented subjects. MI subjects did not have any significant changes in hippocampal volume or WMH. The risk for developing dementia was significantly and comparably increased in subjects with either hippocampal atrophy or high WMH. However, the risk for dementia increased dramatically in subjects with both hippocampal atrophy and a high degree of WMH.

CONCLUSION

Reductions in hippocampal volume may be present before dementia but not until cognitive impairment is relatively severe. Because there is a synergistic effect between high WMH and hippocampal atrophy, interactions between vascular and degenerative processes may be important determinants of dementia.

Fibronectin attachment protein is necessary for efficient attachment and invasion of epithelial cells by Mycobacterium avium subsp. paratuberculosis

Attachment and ingestion of Mycobacterium avium subsp. paratuberculosis by two epithelial cell lines were enhanced by soluble fibronectin (FN). Peptide blocking of the FN attachment protein (FAP-P) inhibited the internalization of M. avium subsp. paratuberculosis. Disruption of FAP-P expression significantly reduced attachment and ingestion of M. avium subsp. paratuberculosis by T-24 and Caco-2 cells. The results indicate that the interaction between FN and FAP-P facilitates attachment and internalization of M. avium subsp. paratuberculosis by epithelial cells.

Exchange nailing for aseptic nonunion of the femoral shaft

Thirty-six nonunions of the femoral shaft were treated by closed removal of previous nails, reaming of marrow cavity as widely as possible, and reinsertion of stable intramedullary nail. Indications included femoral shaft aseptic nonunions with inserted intramedullary nail, nonunions with a radiolucent line, without segmental bony defects, and less than 1 cm shortening. They were followed up for a median of 2.9 (1-6) years. Thirty-three nonunions healed uneventfully within a median period of 4 (3-8) months. Except for three persistent nonunions, no other significant complications occurred.

A sieving method for collecting the metacercariae of trematode parasites from freshwater fish

This study describes a sieving method for the collection of metacercariae from frozen (-20 degrees C) freshwater fish. Digested fish tissue is filtered through a series of sieves; the crude filtrate is then centrifuged. Centrifugation produces a sediment from which metacercariae can be removed. Half of the metracercariae that were obtained from the fish meat that had been frozen for 10 days (-20 degrees C) were dead; the other half were alive and some larvae were moving slowly.

Liver resection for hepatocellular carcinoma in patients with end-stage renal failure

BACKGROUND AND OBJECTIVES

Surgical resection remains the main option for curing hepatocellular carcinoma (HCC). However, liver resection in patients with end-stage renal disease (ESRD) is risky. The aim of this study is to clarify the role of liver resection for treating HCC in patients with ESRD.

METHODS

A retrospective review was carried out on 468 patients who underwent liver resection for HCC between 1989 and 1999. The clinicopathological characteristics and operative results of 12 patients who had ESRD (ESRD group) were compared with those of the other 456 patients who did not have ESRD (non-ESRD group). In the ESRD group, heparin-free hemodialysis using the periodic saline-rinse method was performed during the perioperative period.

RESULTS

The ESRD group had lower hemoglobin and a higher serum creatinine levels. Other patient background and tumor pathological characteristics were comparable between the two groups as well. The operative morbidity and mortality between the two groups were also similar. The 5-year disease-free survival rates for ESRD and non-ESRD groups were 35.0 and 34.2% (P = 0.31), respectively, while the 5-year actuarial survival rates were 67.8 and 53.3% (P = 0.54), respectively.

CONCLUSION

With improving techniques and knowledge of dialysis, liver resection for HCC is justified in selected patients with ESRD.

Molecular identification and characterization of turkey IFN-gamma gene

The cDNAs of turkey and chicken interferon gamma (IFN-gamma) were cloned and the functional activity of turkey and chicken IFN-gamma was compared. The coding region of turkey IFN-gamma gene encodes a predicted mature protein of 145 amino acids with a molecular weight at 16.8 kDa. Compared with type I IFN, the IFN-gamma between turkey and chicken also had the same size and high degree of identity at the nucleotide (96.0%) and amino acid (96.4%) sequence. Turkey IFN-gamma was cross-reactive with chicken cells. Both turkey and chicken IFN-gamma could induce production of nitric oxide by turkey or chicken macrophages. Turkey IFN-gamma also had similar degree of sensitivity to heat and pH 2.0 as chicken IFN-gamma. The functional activity of both turkey and chicken IFN-gamma could be neutralized by a monoclonal antibody specific to chicken IFN-gamma to a similar extent. These results indicated that IFN-gamma protein was cross-reactive between turkey and chicken.

Major histocompatibility complex class II polymorphisms in Macaca mulatta: factors influencing comprehensive genotyping of Macaca mulatta (Mamu)-DQA1 alleles by PCR-RFLP in archival samples

In the last 5 years, HLA class II genotyping methods have been adapted for genotyping of class II loci in rhesus macaques. Since previously published typing protocols were used on samples that were collected and stored under ideal conditions, it was of interest to determine if these methods were adequate for genotyping a large collection of archival samples from which DNA had been isolated and stored under various conditions. Established macaque DQA1 typing protocols were modified to optimize the typing procedure and enhance the ability to successfully genotype DNA from samples that were of poor quality and/or quantity. Long-term storage of whole-blood buffy coats or stored DNA extracted from whole-blood buffy coats did not affect typing success; however, amplification and typing of DNA extracted from archival samples of plasma were difficult and resulted in a low success rate. This suggests that amplification and DQA1-genotyping of archival samples is possible with a modified protocol, but is influenced by the age and source of the sample, and to a lesser extent, the method used to extract DNA from sample substrates.

Ubiquitin-activating enzyme (E1) isoforms in lens epithelial cells: origin of translation, E2 specificity and cellular localization determined with novel site-specific antibodies

Lens development and response to peroxide stress are associated with dramatic changes in protein ubiquitination, reflecting dynamic changes in activity of the ubiquitin-activating enzyme (E1). Two isoforms of E1 (E1A and E1B) have been identified in lens cells although only one E1 mRNA, containing three potential translational start sites, has been detected. Novel, site-specific antibodies to E1 were generated and the hypothesis that the two isoforms of E1 are translated from alternative initiation codons of a single mRNA was tested. Antibodies raised against E1A-N peptide (Met(1)to Cys(23)of E1A) reacted only with E1A by immunoblot and immunoprecipitation. Antibodies raised against E1B-N peptide (Met(1)to Glu(25)of E1B or Met(41)to Glu(65)of E1A) and E1AB-C peptide (His(1030)to Arg(1058)of E1A or His(990)to Arg(1018)of E1B) reacted with both E1A and E1B. These results indicate that (1) E1A and E1B contain the same C-terminal residues; (2) E1A contains the N terminal sequence of E1B; and (3) E1B does not contain the N terminal sequence of E1A. The two isoforms of lens E1 are therefore translated from a single mRNA. Specifically, E1A is translated from the first initiation codon, and E1B translated from the second initiation codon. E1A and E1B were affinity-purified, and their ability to 'charge' ubiquitin carrier proteins (E2s) with activated ubiquitin was compared in a cell-free system. E1A and E1B were indistinguishable with respect to charging different E2s. However, E1 immunolocalization studies with human lens epithelial cells indicate that E1A and E1B are preferentially localized to the nucleus and cytosol, respectively. This observation suggests that E1A and E1B ubiquitinate different proteins and serve different functions in intact cells.

Femoral reconstruction

Reconstruction of the femur is sometimes difficult in patients that may sustain long-term disabilities. Following advancements in modern technology, some femoral disorders which were considered to be recalcitrant in the past can now be treated with satisfactory outcomes. This article reviews the experience of femoral reconstruction at the Orthopedic Department of Chang Gung Memorial Hospital (Linkou). Reconstruction of the femur includes nonunion, malunion, and segment bony defects that require bone transfer. The prerequisite for successful treatment was to follow the biological and biomechanical principles. The author believes that the technique of femoral reconstruction can be developed and simplified so that success rates can be further improved.

Arachidonic acid-induced H+ and Ca2+ increases in both the cytoplasm and nucleoplasm of rat cerebellar granule cells

1. Arachidonic acid (AA) exerts multiple physiological and pathophysiological effects in the brain. By continuously measuring the intracellular pH (pH(i)) and Ca2+ levels ([Ca2+]i) in primary cultured rat cerebellar granule cells, we have found, for the first time, that 20 min treatment with 10 microM AA resulted in marked increases in Ca2+ and H+ levels in both the cytosol and nucleus. 2. A much higher concentration (40 mM) of another weak acid, propionic acid, was needed to induce a similar change in pH(i). The [Ca2+]i increase was probably caused by AA-induced activation of Ni2+-sensitive cationic channels, but did not involve NMDA channels or the Na+-Ca2+ exchanger. 3. AA-induced acidosis occurs by a different mechanism involving predominantly the passive diffusion of the un-ionized form of AA, rather than a protein carrier, as proposed by Kamp & Hamilton for fatty acids (FAs) in artificial phospholipid bilayers (the 'flip-flop' model). The following results, which are similar to those observed in lipid bilayers, support this conclusion: (1) FAs containing a -COOH group (AA, linoleic acid, alpha-linolenic acid, and docosahexaenoic acid) induced intracellular acidosis, whereas a FA with a -COOCH3 group (AA methyl ester) had little effect on pH(i), (2) a FA amine, tetradecylamine, induced intracellular alkalosis, and (3) the AA-/FA-induced pH(i) changes were reversed by bovine serum albumin. 4. Further evidence in support of a passive diffusion model, rather than a membrane protein carrier, is that: (1) there was a linear relationship between the initial rate of acid flux and the concentration of AA (2-100 microM), (2) acidosis was not inhibited by 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid, a potent inhibitor of the plasma membrane FA carrier protein, and (3) the involvement of most known H+-related membrane carriers and H+ conductance has been ruled out. 5. Since AA can be released under both physiological and pathophysiological conditions, the possible significance of the AA-evoked increases in H+ and Ca2+ in both the cytoplasm and nucleoplasm is discussed.

Standardization of broth microdilution and disk diffusion susceptibility tests for Actinobacillus pleuropneumoniae and Haemophilus somnus: quality control standards for ceftiofur, enrofloxacin, florfenicol, gentamicin, penicillin, tetracycline, tilmicosin, and trimethoprim-sulfamethoxazole

Quality control (QC) standards for the in vitro antimicrobial susceptibility testing of two fastidious veterinary pathogens, Actinobacillus pleuropneumoniae and Haemophilus somnus, were developed in a multilaboratory study according to procedures established by the National Committee for Clinical Laboratory Standards for broth microdilution and disk diffusion testing. The medium recommended for the broth microdilution testing is cation-adjusted Mueller-Hinton broth supplemented with 2% lysed horse blood, 2% yeast extract, and 2% supplement C. This medium has been designated veterinary fastidious medium. The medium recommended for the disk diffusion testing is chocolate Mueller-Hinton agar. The recommended QC organisms are A. pleuropneumoniae ATCC 27090 and H. somnus ATCC 700025. The QC MICs of ceftiofur, enrofloxacin, florfenicol, gentamicin, penicillin, tetracycline, tilmicosin, and trimethoprim-sulfamethoxazole were determined for each isolate, as were the zone size ranges. Of the results from the participating laboratories, 94.0% of the zone diameter results and 97.0% of the MIC results fell within the suggested QC ranges for all compounds. These QC guidelines should allow greater accuracy in interpreting results when testing these antimicrobial agents against fastidious pathogens.

DNA-mediated vaccination against infectious bursal disease in chickens

The objective of the present study was to investigate the feasibility of a DNA vaccine to protect chickens against infectious bursal disease virus (IBDV) infection. A plasmid DNA carrying VP2, VP4, and VP3 genes of the standard challenge (STC) strain of IBDV was constructed and designated as pCR3.1-VP243-STC. One-day-old chickens were intramuscularly injected with the plasmid pCR3.1-VP243-STC once (group D1), twice (group D2), or three times (group D3) at weekly intervals. Chickens at 3 weeks old were orally inoculated with IBDV strain STC and observed for 10 days after challenge. Immunization twice (group D2) or three times (group D3) with the plasmid pCR3.1-VP243-STC conferred protection for 50-100 or 80-100% of chickens, respectively, as evidenced by the absence of clinical signs, mortality, and bursal atrophy. Although chickens vaccinated once (group D1) with the plasmid pCR3.1-VP243-STC did not have clinical signs, they exhibited varying degree of bursal atrophy after challenge. Enzyme-linked immunosorbent assay (ELISA) antibody titers in chickens protected by the plasmid pCR3.1-VP243-STC were significantly lower (P<0.05) than those not protected 10 days after challenge. IBDV antigen was not detected in the bursae of chickens that were protected by receiving the plasmid pCR3.1-VP243-STC twice or three times. The results indicate that the constructed plasmid pCR3.1-VP243-STC as a DNA vaccine provided efficacious protection for chickens against IBDV infection.

Using color histogram normalization for recovering chromatic illumination-changed images

We propose a novel image-recovery method using the covariance matrix of the red-green-blue (R-G-B) color histogram and tensor theories. The image-recovery method is called the color histogram normalization algorithm. It is known that the color histograms of an image taken under varied illuminations are related by a general affine transformation of the R-G-B coordinates when the illumination is changed. We propose a simplified affine model for application with illumination variation. This simplified affine model considers the effects of only three basic forms of distortion: translation, scaling, and rotation. According to this principle, we can estimate the affine transformation matrix necessary to recover images whose color distributions are varied as a result of illumination changes. We compare the normalized color histogram of the standard image with that of the tested image. By performing some operations of simple linear algebra, we can estimate the matrix of the affine transformation between two images under different illuminations. To demonstrate the performance of the proposed algorithm, we divide the experiments into two parts: computer-simulated images and real images corresponding to illumination changes. Simulation results show that the proposed algorithm is effective for both types of images. We also explain the noise-sensitive skew-rotation estimation that exists in the general affine model and demonstrate that the proposed simplified affine model without the use of skew rotation is better than the general affine model for such applications.

Pulsatility of ascending aorta and restenosis after coronary angioplasty in patients >60 years of age with stable angina pectoris

A recent study has demonstrated that the pulsatility of the ascending aorta is a strong predictive factor for restenosis after coronary angioplasty. However, whether the pulsatility of the ascending aorta is still a significant predictor for restenosis in elderly patients with a stiffer aorta is unknown. We investigated the relation between arterial pulsatility in the ascending aorta and restenosis after coronary angioplasty in patients aged > 60 years. Eighty-seven consecutive patients (80 men, aged 72.5 +/- 5.1 years) with stable angina were included. Before angioplasty, the arterial systolic, diastolic, and mean pressure waveforms of the ascending aorta were measured. We used fractional pulse pressure (PPf, the ratio of pulse pressure to mean pressure) and pulsatility index (PI, the ratio of pulse pressure to diastolic pressure) to estimate the pulsatility of the ascending aorta. Angiographic restenosis occurred in 39 patients. Pulse pressure, PPf, and PI were significantly higher in patients with restenosis after coronary angioplasty (restenosis vs without restenosis: pulse pressure, 77.6 +/- 12.2 vs 66.1 +/- 15.4 mm Hg [p < 0.001]; PPf, 0.80 +/- 0.09 vs 0.69 +/- 0.11 [p < 0.001]; PI, 1.19 +/- 0.20 vs 0.98 +/- 0.21 [p < 0.001]). After multivariate stepwise adjustment of risk factors of restenosis and using receiver-operating characteristic analysis, the odds ratio (OR) of restenosis was: pulse pressure > 66 mm Hg, OR 5.88 (95% confidence interval [CI] 2.17 to 15.93); PPf > 0.72, OR 13.71 (95% CI 4.81 to 39.05); PI > 1.06, OR 13.56 (95% CI 4.67 to 39.38). Moreover, among patients aged > 70 years (n = 60), the predictive values of PPf and PI were even higher than those in patients aged < or = 70 years (n = 27). Thus, in elderly patients with stable angina, the pulsatility of the ascending aorta is a powerful predictor of restenosis after coronary angioplasty.

Derangement of heart rate variability during a catastrophic earthquake: a possible mechanism for increased heart attacks

At 1:47 AM on September 21, 1999, the middle part of Taiwan was struck by a major earthquake measuring 7.3 on the Richter scale. It has been shown that the mental stress caused by an earthquake could lead to a short- or long-term increase in frequency of cardiac death probably through activation of the sympathetic nervous system. The aim of this study was to investigate the effects of emotional stress on the autonomic system during an actual earthquake. Fifteen patients receiving a 24-hour Holter ECG study starting from 10+/-4 hours before the onset of the earthquake were included for the analysis of time- and frequency-domains of heart rate variability (HRV) at several time periods. A 24-hour Holter study recorded 2-6 months before the earthquake in 30 age- and sex-matched subjects served as the control group. Heart rate and the low frequency (LF) to high frequency (HF) ratio increased significantly after the earthquake and were attributed mainly to the withdrawal of the high frequency component (parasympathetic activity) of HRV. Sympathetic activation was blunted in elderly subjects > 60 years old. The concomitant ST-T depression observed in the Holter study correlated with a higher increment of LF as compared to HF components. The changes observed in HRV recovered completely 40 minutes following the earthquake. The derangement of HRV results from the withdrawal of the parasympathetic component and the arousal of sympathetic activity by the stressful earthquake. However, this autonomic derangement returned towards normal 40 minutes following the earthquake.

Synthesis of 1-benzyl-3-(5'-hydroxymethyl-2'-furyl)indazole analogues as novel antiplatelet agents

1-Benzyl-3-(5'-hydroxymethyl-2'-furyl)indazole (28, YC-1) was selected as the lead compound for systemic structural modification. After screening for antiplatelet activity, SARs of YC-1 analogues were established. Among these potent active derivatives, compounds 29, 30, 31, 44, and 45 functioned as potent activators of sGC and inhibitors of PDE5 with potency comparable to that of YC-1. In addition, compound 58 was found to be a selective and potent inhibitor of protease-activated receptor type 4 (PAR4)-dependent platelet activation.