[Diagnostic value of rapid antigen testing for the detection of SARS-CoV-2 infection]

Objective: To investigate the diagnostic value of rapid antigen test based on colloidal gold immunochromatographic assay for the detection of SARS-CoV-2 infection in symptomatic patients. Methods: From May 20 to June 5 2022, 76 hospitalized children and their 55 accompanying family members with confirmed SARS-CoV-2 infection in the COVID-19 isolation unit of the Children's Hospital of Fudan University (designated referral hospital for SARS-CoV-2 infection in Shanghai) enrolled. Their nasopharyngeal swab specimens were consecutively collected. The samples were tested for SARS-CoV-2 nucleic acid by real-time quantitative. SARS-CoV-2 antigen was tested by immunochromatography. The correlation between the antigen detection results and the change of the cycle threshold (Ct) values were evaluated, as well as the sensitivity and specificity of SARS-CoV-2 antigen detection at different periods after the onset of the disease. Kappa consistency test was conducted to investigate the consistency between the 2 diagnostic methods. Results: Of the enrolled SARS-CoV-2 symptomatic infections, 76 were children, including 41 males and 35 females, with an age of 5 (2, 9) years; 55 were accompanying families, including 8 males and 47 females, with an age of 38 (32, 41) years. All 478 samples were simultaneously tested for SARS-CoV-2 antigen and nucleic acid. In any period from disease onset to negative conversion of viral nucleic acid, the overall sensitivity of the rapid antigen test was 48.2% (119/247), the specificity was 98.3% (227/231), and antigen test and nucleic acid test showed moderate consistency (κ=0.46, P<0.05). The sensitivity of antigen test was 100% (82/82) when the Ct value was ≤25. And the sensitivity of antigen test was 8/10, 4/15 and 8.3% (3/36) when the Ct value was 26, 30 and 35, respectively. All antigen tests were negative when Ct value was >35. During the period of 1-2 days, 3-5 days, 6-7 days, 8-10 days and >10 days after onset, the sensitivity and specificity of SARS-CoV-2 antigen test were 5/8 and 5/5, 90.2% (37/41) and 5/5, 88.9% (24/27) and 2/5, 45.0% (36/80) and 94.1% (32/34), 18.7% (17/91) and 98.9% (183/185) respectively. The Ct values of nasopharyngeal swabs were<26 during 2 to 7 days after onset, 28.7±5.0 on day 8, 34.5±2.9 on day 13 and > 35 after 14 days, respectively. Conclusion: SARS-CoV-2 antigen test in the patients with SARS-CoV-2 infection shows acceptable sensitivity and specificity within 7 days after onset of disease, and the sensitivity was positively correlated with viral load and negatively correlated with onset time.

[Clinical analysis of liver chemistries in children and adolescent with 2019-nCoV infection]

Objective: To describe the clinical features of liver involvement in children and adolescent with 2019-nCoV infection. Methods: The clinical data of 77 hospitalized cases admitted to the Children's Hospital of Fudan University were collected from January 19 to November 28, 2020. The characteristics and risk factors of abnormal liver chemistries in children with laboratory-confirmed 2019-nCoV infection were analyzed. Results: Of the 77 cases, 44 were male (57.1%) and 33 were female (42.9%), with a median age of 10 years. 27(35.1%) were asymptomatic, 28(36.4%) had mild illness, 22(28.6%)had non-severe pneumonia. Hydroxychloroquine was used in 7 cases. Of the 75 children without underlying diseases, alanine aminotransferase was elevated in 1 case (1.5%, during hydroxychloroquine therapy), aspartate aminotransferase was elevated in 7 cases (10.3%), alkaline phosphatase was elevated in 7 cases (28%), and total bilirubin, direct bilirubin, albumin, international normalized ratio were in normal range. There was no statistical difference between the pneumonia group and the non-pneumonia group in term of liver chemistries (P > 0.05), same as between the elevated erythrocyte sedimentation rate group and the normal group. There was no aggravation of liver injury in the child with biliary atresia. The child with epilepsy showed no abnormal liver chemistries after infection. Conclusion: Children with 2019-nCoV infection had mild clinical symptoms with few cases of liver injury. The abnormal liver chemistries in children with COVID-19 infection may be related to the underlying disease and the use of antiviral drugs.

Flexible and Integrated Sensing Platform of Acoustic Waves and Metamaterials based on Polyimide-Coated Woven Carbon Fibers

Versatile, in situ sensing and continuous monitoring capabilities are critically needed, but challenging, for components made of solid woven carbon fibers in aerospace, electronics, and medical applications. In this work, we proposed a unique concept of integrated sensing technology on woven carbon fibers through integration of thin-film surface acoustic wave (SAW) technology and electromagnetic metamaterials, with capabilities of noninvasive, in situ, and continuous monitoring of environmental parameters and biomolecules wirelessly. First, we fabricated composite materials using a three-layer composite design, in which the woven carbon fiber cloth was first coated with a polyimide (PI) layer followed by a layer of ZnO film. Integrated SAW and metamaterials devices were then fabricated on this composite structure. The temperature of the functional area of the device could be controlled precisely using the SAW devices, which could provide a proper incubation environment for biosampling processes. As an ultraviolet light sensor, the SAW device could achieve a good sensitivity of 56.86 ppm/(mW/cm²). On the same integrated platform, an electromagnetic resonator based on the metamaterials was demonstrated to work as a glucose concentration monitor with a sensitivity of 0.34 MHz/(mg/dL).

Defining Ischemic Core in Acute Ischemic Stroke Using CT Perfusion: A Multiparametric Bayesian-Based Model

BACKGROUND AND PURPOSE

The Bayesian probabilistic method has shown promising results to offset noise-related variability in perfusion analysis. Using CTP, we aimed to find optimal Bayesian-estimated thresholds based on multiparametric voxel-level models to estimate the ischemic core in patients with acute ischemic stroke.

MATERIALS AND METHODS

Patients with anterior circulation acute ischemic stroke who had baseline CTP and achieved successful recanalization were included. In a subset of patients, multiparametric voxel-based models were constructed between Bayesian-processed CTP maps and follow-up MRIs to identify pretreatment CTP parameters that were predictive of infarction using robust logistic regression. Subsequently CTP-estimated ischemic core volumes from our Bayesian model were compared against routine clinical practice oscillation singular value decomposition-relative cerebral blood flow <30%, and the volumetric accuracy was assessed against final infarct volume.

RESULTS

In the constructed multivariate voxel-based model, 4 variables were identified as independent predictors of infarction: TTP, relative CBF, differential arterial tissue delay, and differential mean transit time. At an optimal cutoff point of 0.109, this model identified infarcted voxels with nearly 80% accuracy. The limits of agreement between CTP-estimated ischemic core and final infarct volume ranged from -25 to 27 mL for the Bayesian model, compared with -61 to 52 mL for oscillation singular value decomposition-relative CBF.

CONCLUSIONS

We established thresholds for the Bayesian model to estimate the ischemic core. The described multiparametric Bayesian-based model improved consistency in CTP estimation of the ischemic core compared with the methodology used in current clinical routine.

Bariatric surgery is associated with increased risk of new-onset inflammatory bowel disease: case series and national database study

BACKGROUND

Case series suggest a possible association between bariatric surgery and incident IBD.

AIM

The aim of this study was to evaluate the association between bariatric surgery and new-onset IBD.

METHODS

We first conducted a multi-institutional case series of patients with a history of IBD and bariatric surgery. We next conducted a matched case-control study using medical and pharmacy claims from 2008 to 2012 in a US national database from Source Healthcare Analytics LLC. Bariatric surgery was defined by ICD-9 or CPT code. Bariatric surgery was evaluated as recent (code in database timeframe), past (past history V code) or no history. Conditional logistic regression was used to estimate odds ratios (OR) and 95% CI for new-onset IBD, CD and UC.

RESULTS

A total of 15 cases of IBD (10 CD, 4 UC, 1 IBD, type unclassified) with a prior history of bariatric surgery were identified. Most cases were women, had Roux-en-Y surgery years prior to diagnosis and few IBD-related complications. A total of 8980 cases and 43 059 controls were included in our database analysis. Adjusting for confounders, a past history of bariatric surgery was associated with an increased risk of new-onset IBD (OR 1.93, 95% CI 1.34-2.79). However, patients who had recent bariatric surgery did not appear to be at shorter term risk of IBD (OR 0.94, 95% CI 0.58-1.52).

CONCLUSION

New-onset IBD was significantly associated with a past history of bariatric surgery. This potential association needs to be confirmed in future prospective studies.

High-efficiency Q-switched dual-wavelength emission at 1176 and 559 nm with intracavity Raman and sum-frequency generation

An efficient Q-switched dual-wavelength laser with self-frequency Raman conversion in composite Nd:YVO(4) and intracavity sum-frequency generation in BBO is reported. With an input pump power of 17.5 W, average power of 0.53 W at the first-Stokes 1176 nm and average power of 1.67 W at the sum-frequency mixed 559 nm are simultaneously generated at a pulse repetition rate of 100 kHz, corresponding to a total conversion efficiency of 12.5%.

Efficient high-peak-power AlGaInAs eye-safe wavelength disk laser with optical in-well pumping

We have demonstrated an efficient high-peak-power AlGaInAs eye-safe wavelength disk laser at 1555 nm. The quantum defect and the thermal load are significantly reduced by pumping the quantum well directly. The overall conversion efficiency is enhanced over three times compared with the barrier pumping method. With a pump peak power of 3.7 kW, an output peak power of 0.52 kW is generated at a pulse repetition rate of 20 kHz.

Compact efficient Q-switched eye-safe laser at 1525 nm with a double-end diffusion-bonded Nd:YVO4 crystal as a self-Raman medium

We report on an efficient Q-switched eye-safe laser at 1525 nm with a double-end diffusion-bonded Nd:YVO(4) crystal as a self-Raman gain medium. A diffusion-bonded crystal not only reduces the thermal effects but also increase the interaction length for the stimulated Raman scattering. With an input pump power of 17.2 W, average power of 2.23 W at the first- Stokes wavelength of 1525 nm is generated at a pulse repetition rate of 40 kHz, corresponding to a conversion efficiency of 13%.

Subnanosecond mJ eye-safe laser with an intracavity optical parametric oscillator in a shared resonator

We theoretically verify that the threshold of an intracavity optical parametric oscillator pumped by a passively Q-switched laser is entirely controlled by the bleach of the saturable absorber not by the signal output reflectivity. We use a series of different output couplers to optimize the output performance. With a signal output reflectivity of 15%, we experimentally achieve an efficient subnanosecond eye-safe laser with 3.3 mJ pulse energy and 1.5 MW peak power.

Passive Q switching of Er-Yb fiber laser with semiconductor saturable absorber

A high-performance AlGaInAs quantum-well saturable absorber is developed for passively Q-switched Er-Yb double-clad fiber lasers at 1560 nm. With an incident pump power of 13.5 W, an average output power of 1.26 W with a pulse repetition rate of 12 kHz is obtained. The maximum peak power is greater than 500 W.

Assessment of intervention measures for the 2003 SARS epidemic in Taiwan by use of a back-projection method

OBJECTIVES

To reconstruct the infection curve for the 2003 severe acute respiratory syndrome (SARS) epidemic in Taiwan and to ascertain the temporal changes in the daily number of infections that occurred during the course of the outbreak.

METHOD

Back-projection method.

RESULTS

The peaks of the epidemic correspond well with the occurrence of major infection clusters in the hospitals. The overall downward trend of the infection curve after early May corresponds well to the date (May 10) when changes in the review and classification procedure were implemented by the SARS Prevention and Extrication Committee.

CONCLUSION

The major infection control measures taken by the Taiwanese government over the course of the SARS epidemic, particularly those regarding infection control in hospitals, played a crucial role in containing the outbreak.

Arsenite-induced nitric oxide generation is cell cycle-dependent and aberrant in NBS cells

Exposure to arsenic has been reported to cause DNA damage and eventually the occurrence of bladder, lung and skin cancers. A previous report has demonstrated that arsenite-induced phosphorylation of Mre11, a protein involved in the repair of DNA double strand breaks (DSBs), is M phase-dependent and requires the Nijmegen breakage syndrome (NBS) protein, NBS1 [DNA Repair 1 (2002) 137]. Furthermore, arsenite treatment arrests cells at the M phase and the cells eventually go through apoptosis [Biochemical Pharmacology 60 (2000) 771]. Here we demonstrate that arsenite treatment enhances the generation of nitric oxide (NO), and that the enhanced NO generation is dominant at the G2/M phase. Arsenite-induced NO generation is impaired in DSB repair-defective NBS cells, but not in NBS1-reconstituted NBS cells, suggesting NBS1 is required for effective NO generation. In summary, our study showed, for the first time, that arsenite-induced NO generation is cell-cycle- and NBS1-dependent.

Observations of blanket characteristics in full-scale floc blanket clarifiers

We monitored the changes in concentrations, zeta potentials, sizes and capillary suction times of the solids flocs in the clarified water from eight floc blanket clarifiers of PingTsan Water Works of Taiwan Water Supply Company with low (< 10 NTU) and high (> 100 NTU) turbidity raw water. For the former, one-stage coagulation-sedimentation treatment was adopted which yielded a rather unstable blanket. Complete washout was noticeable when the PACl dosage was insufficient. On the treatment of high-turbidity raw water, on the other hand, the Works adopted the combined treatment process, that is, the raw water was first coagulated and settled in a pre-sedimentation tank, afterwards, its effluent was coagulated again and clarified in the clarifiers. The resulting flocs could form a networked blanket that was relatively stable to the shock load in raw water turbidity.

Luteolin inhibits the growth and arylamine N-acetyl-transferase activity in Neisseria gonorrhoeae

Growth inhibition and arylamine N-acetyltransferase (NAT) activity in Neisseria gonorrhoeae were inhibited by luteolin, a drug which originated from herbs. The growth inhibition was based on changes in optical density (OD) using a spectrophotometer, and arylamine NAT activity with 2-aminofluorene (2-AF) was determined using high pressure liquid chromatography. The inhibition of growth in N. gonorrhoeae demonstrated that luteolin elicited a dose-dependent growth inhibition in the N. gonorrhoeae cultures. Suspensions of N. gonorrhoeae with or without specific concentrations of luteolin cotreatment showed different percentages of 2-AF acetylation. The data indicated that there was reduced NAT activity associated with increased levels of luteolin in N. gonorrhoeae suspensions. Time-course experiments showed that NAT activity measured from intact N. gonorrhoeae cells was inhibited by luteolin for at least 4 h. Using standard steady-state kinetic analysis, it was demonstrated that luteolin was a possible uncompetitive inhibitor to NAT activity in N. gonorrhoeae. This report is the first to show that luteolin can inhibit N. gonorrhoeae NAT activity.

Effects of berberine on arylamine N-acetyltransferase activity and 2-aminofluorene-DNA adduct formation in human leukemia cells

Berberine is an alkaloid occurring in the plant genera Berberis and Coptis. Although berberine had been demonstrated to have antineoplastic function by inhibiting DNA-synthesis in activated lymphocytes, there is no available information to address berberine affects on human leukemia cell N-acetyltransferase (NAT) activity and 2-aminofluorene (AF)-DNA adduct formation. Thus, berberine was tested for inhibition of arylamine NAT activity and AF-DNA adduct formation in human leukemia cells. The NAT activity was measured by a high performance liquid chromatography assaying for the amounts of N-acetyl-2-aminofluorene (AAF) and N-acetyl-p-aminobenzoic acid (N-Ac-PABA) and the remaining AF and p-aminobenzoic acid (PABA). The NAT activity and AF-DNA adduct formation in human leukemia cells were inhibited by berberine in a dose-dependent manner, i.e. the higher the concentration of berberine, the higher the inhibition of NAT activity and AF-DNA adduct. The data also indicate that berberine decreased the apparent values of Km and Vmax from human leukemia cells in both cytosol and intact cells.

Lip lead as an alternative measure for lead exposure assessment of lead battery assembly workers

This study investigated lead exposures of lead battery assembly workers in Taiwan. A special attempt was made to evaluate the use of lip lead as an alternative index for occupational lead exposure. Ninety-six of 113 workers from a lead battery plant were recruited as study subjects. Air lead; lead loadings on workers' sleeves, gloves, hands, cheeks, and lips; and blood lead were determined for exposure assessment. A questionnaire also was administered to collect information on work history, suspected exogenous lead sources, and personal behavior and activities. Geometric means of total air lead at different subareas ranged from 0.070 (2.5 geometric standard deviation [GSD]) to 0.159 (1.8 GSD) mg/m3. Geometric means of respirable air lead level for different subgroups of workers varied from 0.009 (2.0 GSD) to 0.032 (1.9 GSD) mg/m3, whereas those of the blood lead level ranged from 22.4 (1.3 GSD) to 44.5 (1.3 GSD) microg/dL. The heaviest lead loadings were found for plate-processing workers (e.g., 66.4 [1.5 GSD] on gloves, 0.80 [3.7 GSD] on cheeks, and 0.79 [3.2 GSD] microg/cm2) on bare-hands after washing. Blood lead level was significantly correlated with lead levels in air, lead loadings on lips, and bare hands after washing (r=0.24-0.30). Results of multiple regression analysis showed that only lip lead had a significant effect on the blood lead, whereas respirable air lead and personal behavior had only mild effects in this model. It was concluded that lip lead level may be used as an alternative index of lead exposure to facilitate the estimation of lead uptake through ingestion.

Effects of VEGF121 and/or VEGF165 gene transfection on collateral circulation development

BACKGROUND AND PURPOSE

Angiogenesis is regulated by various factors, including vascular endothelial growth factor (VEGF). Five isoforms of VEGF have been discovered: VEGF121, VEGF145, VEGF165, VEGF189, and VEGF206. The teleologic basis for the various VEGF isoforms remains unclear, but different VEGF isoforms may mediate distinct endothelial cell functions such as angiogenesis, vascular permeability, and differentiation. We sought to determine the effects of various VEGF isoforms on angiogenesis under ischemic conditions in rabbits.

METHODS

The effects of VEGF121 and/or VEGF165 gene transfection on collateral circulation development in ischemic rabbit hindlimb muscles were investigated by using naked plasmids encoding VEGF121 or VEGF165 (pVEGF121 or pVEGF165), either individually or in combination. pCMV beta was used as the control plasmid. The femoral artery on one side of New Zealand White rabbits was ligated. Ten days later, the ischemic muscles received direct intramuscular injection of pVEGF121 (500 micrograms), pVEGF165 (500 micrograms), or pVEGF121 (250 micrograms) + pVEGF165 (250 micrograms) in experimental groups, while pCMV beta (500 micrograms) was used in the control group. Therapeutic effects were evaluated 30 days later by anatomic and physiologic analysis.

RESULTS

Internal iliac angiography showed strong development of collateral circulation in all of the pVEGF-treated groups. In contrast, collateral arteries developed weakly in the control group. Combination treatment with both pVEGF121 and pVEGF165 did not result in additional improvement compared with pVEGF121 or pVEGF165 treatment alone (angiographic scores: pVEGF121 = 0.85 +/- 0.10; pVEGF165 = 0.81 +/- 0.11; pVEGF121 + pVEGF165 = 0.83 +/- 0.09; control = 0.53 +/- 0.09; p < 0.01). A favorable response in the development of circulation at the capillary level with pVEGF121 and/or pVEGF165 versus pCMV beta was also found. Blood pressure measurement and regional blood flow measurement using colored microspheres revealed similar results.

CONCLUSIONS

Our results show that direct intramuscular injection of naked DNA encoding VEGF121 or VEGF165, individually or in combination, is an effective method for gene transfer in an animal model of ischemic limbs and results in augmented collateral vascular development and tissue perfusion.

Perceptual alternation in obsessive compulsive disorder--implications for a role of the cortico-striatal circuitry in mediating awareness

Mounting evidence suggests that obsessive compulsive disorder (OCD) results from functional aberrations of the fronto-striatal circuitry. However, empirical studies of the behavioral manifestations of OCD have been relatively lacking. The present study employs a behavioral task that allows a quantitative measure of how alternative percepts are formed from one moment to another, a process mimicking the brain state in which different thoughts and imageries compete for access to awareness. Eighteen patients with OCD, 12 with generalized anxiety disorder, and 18 normal subjects participated in the experiment, in which they viewed one of the three Schröder staircases and responded by pressing a key to each perceptual reversal. The results demonstrate that the patients with OCD have a higher perceptual alternation rate than the normal controls. Moreover, the frequency of perceptual alternation is significantly correlated with the Yale-Brown obsessive compulsive and the Hamilton anxiety scores. The increase in the frequency of perceptual reversals cannot easily be accounted for by learning or by different patterns of eye fixations on the task. These results provide further evidence that an impairment of the inhibitory function of the cortico-striatal circuitry might underlie the etiology of OCD. The implications of the results for a general role of the cortico-striatal circuitry in mediating awareness are discussed.

Adolescent hyperactivity and general psychopathology

The aim of this study was to explore the relationship between activity and psychopathology in adolescents. A total of 289 high school students completed the Symptom Check List-90-R (SCL-90-R) and Wender Utah Rating Scale (WURS) in December 1998. The WURS was used to measure the students' activity level and the SCL-90-R was used as a measure of general psychopathology. Forty-one students (14.18%) scored higher than 46, the cut-off point for differentiation of attention deficit hyperactivity disorder (ADHD) from the general population according to Ward's report, in the WURS (WURS(+)). The WURS(+) students scored significantly higher than the WURS(-) students in all the subscales of SCL-90-R. The prevalence rate of adolescent WURS(+) in this study is 14.18%. This result shows that ADHD adolescents have overlapping symptoms with depression.

Effects of caffeic acid, chlorogenic acid and ferulic acid on growth and arylamine N-acetyltransferase activity in Shigella sonnei (group D)

Arylamine N-acetyltransferase (NAT) activities with 2-aminofluorene (2-AF) as substrates were determined in Shigella sonnei (group D) collected from patients with diarrhoeal disease. The NAT activity was determined using an acetyl CoA recycling assay and high pressure liquid chromatography. Inhibition of growth studies from S. sonnei (group D) demonstrated that caffeic acid (CA), chlorogenic acid (CGA) and ferulic acid (FA) elicited a dose-dependent bactericidal effect in S. sonnei (group D) cultures, i.e. the greater the concentration of CA, CGA and FA, the greater the inhibition of growth of S. sonnei (group D). Cytosols or suspensions of S. sonnei (group D) with and without selected concentrations of CA, CGA and FA co-treatment showed different percentages of 2-AF acetylation. The data indicated that there was reduced NAT activity associated with increased CA, CGA and FA in Shigella dysenteriae (group D) cytosols and intact cells. For the cytosol and intact bacteria examinations, the apparent values of K(m) and Vmax decreased after being co-treated with 400 microM CA, CGA and FA. This report is the first demonstration of plant phenolic inhibition (CA, CGA and FA) of arylamine NAT activity and growth in the bacterium S. sonnei (group D).

Inhibition of N-acetyltransferase activity and DNA-2-aminofluorene adducts by glycyrrhizic acid in human colon tumour cells

Glycyrrhizic acid (GA) was tested for inhibition of arylamine N-acetyltransferase (NAT) activity in a human colon tumour (adenocarcinoma) cell line (colo 205). Two assay systems were performed, one with cellular cytosols (9000g supernatant), the other with intact colon tumour cell cultures. The NAT activity in a human colon tumour cell line was inhibited by GA in a dose-dependent manner in both types of systems examined. The data also indicated that GA decreased the apparent values of K(m) and V(max) of NAT enzymes from human colon tumour cells in both examined systems. The DNA-2-aminofluorene adduct formation in human colon tumour cells were inhibited by GA. This report is the first to demonstrate that GA does inhibit human colon tumour cell NAT activity and DNA adduct formation.

Paeonol promoted 2-aminofluorene and p-aminobenzoic acid acetylations by mononuclear leucocytes from Sprague-Dawley rats

Following exposure of rats to the arylamine carcinogen 2-aminofluorene, DNA-carcinogen adducts were found in the target tissues of the liver and bladder, and also in circulating leucocytes. This work investigated how paeonol affects arylamine (2-aminofluorene and p-aminobenzoic acid) acetylations in rat leucocytes. Evidence is presented showing that rat mononuclear leucocytes are capable of acetylating 2-aminofluorene and p-aminobenzoic acid. Paeonol promoted 2-aminofluorene and p-aminobenzoic acid acetylation. Cultured lymphocytes produced about twice as much N-acetyl-2-aminofluorene from 2-aminofluorene and 2.2-fold as much N-acetyl-p-aminobenzoic acid from p-aminobenzoic acid as monocytes. After cotreatment with paeonol, the lymphocyte and monocyte cultures indicated that paeonol did increase 2-aminofluorene and p-aminobenzoic acid acetylations.

Effects of the immunomodulator tilorone on the acetylation of 2-aminofluorene and DNA-2-aminofluorene adducts in the rats

The present studies were undertaken to determine the effect of tilorone dihydrochloride (a synthetic interferon inducer) on the in vivo acetylation of 2-aminofluorene and DNA-2-aminofluorene adducts. For in vivo examination, pretreatment with tilorone dihydrochloride (50 mg/kg) 48 hr prior to the administration of 2-aminofluorene (50 mg/kg) resulted in a 35% and 29% increase in the fecal and urinary recovery of N-acetyl-2-aminofluorene and a 52% increase in the metabolic clearance of 2-aminofluorene to N-acetyl-2-aminofluorene. Following the exposure of rats to the 2-aminofluorene with or without pretreatment with tilorone dihydrochloride, DNA-2-aminofluorene adducts were determined in liver, bladder, lung and also in circulating leukocytes. The DNA-2-aminofluorene adducts in liver were increased by pretreatment with tilorone dihydrochloride. This is the first demonstration of tilorone-induced increasing in N-acetylation of carcinogens and DNA-carcinogen adducts in vivo.

Effects of aspirin on arylamine N -acetyltransferase activity and DNA adducts in human bladder tumour cells

Aspirin (acetylsalicylic acid) was used to determine the inhibition of arylamine N-acetyltransferase (NAT) activity and DNA adduct formation in a human bladder tumour cell line (T24). The activity of NAT was measured by high-performance liquid chromatography, assaying for the amounts of N-acetyl-2-aminofluorene and N-acetyl-p-aminobenzoic acid and remaining 2-aminofluorene and p-aminobenzoic acid. Two assay systems were used: one with cytosol and the other with intact cells. High-performance liquid chromatography was also used to analyse for the 2-aminofluorene-DNA adducts. Intact bladder tumour cells were used. The results demonstrated that NAT activity and 2-aminofluorene-DNA adduct formation in human bladder tumour cells were inhibited by acetylsalicylic acid in a dose-dependent manner. The effects of acetylsalicylic acid on the values of the apparent K(m) and V(max) were also determined in both examined systems. The data also indicated that acetylsalicylic acid decreased the apparent values of K(m) and V(max) from human bladder tumour cells in both cytosol and intact cells.

Imported malaria: successful treatment of 31 patients in the era of chloroquine resistance

The diagnosis and management of imported malaria presents a continuing challenge in developed countries, including Taiwan. We retrospectively analyzed the records of all 31 patients with imported malaria treated at National Taiwan University Hospital from January 1984 through December 1998. Plasmodium falciparum was identified as the causative malarial parasite in 18 patients, P. vivax in 12, and P. ovale in one. All 31 patients had fever, but only 13 presented with the characteristic fever pattern. The most common initial laboratory abnormalities were thrombocytopenia (20/31), mild hyperbilirubinemia (20/31), and leukopenia (7/31). The median time from the onset of fever to the correct diagnosis was 4 days for P. falciparum and 5 days for P. vivax. In 28 cases, the clue that led to early diagnosis was the patient's travel history. Quinine, but not chloroquine, was effective in 17 out of 18 cases of falciparum malaria. Three patients treated with intravenous quinine required a change of regimen because of life-threatening quinine toxicity; artesunate served as a safe and effective alternative in this situation. While most patients with tertian malaria were cured with the standard chloroquine and primaquine regimen, a higher dosage was required for one case acquired in Papua New Guinea. All patients, including two with severe malaria, survived. We conclude that, the mortality of imported malaria in the chloroquine resistance era can be minimized with early recognition by obtaining a thorough travel history, and instituting appropriate antimalarial chemotherapy based on precise identification of species. Quinine toxicity should be closely monitoried, especially when this drug is given intravenously.

Effects of berberine on arylamine N-acetyltransferase activity in human colon tumor cells

Berberine was used to determine loss of viable cells and inhibition of arylamine Nacetyltransferase (NAT) activity in a human colon tumor (adenocarcinoma) cell line. The viable cells were determined by trypan blue exclusion under a light microscope. The NAT activity was measured by high performance liquid chromatography for the amounts of N-acetyl-2-aminofluorene (AAF), N-acetyl-p-aminobenzoic acid (N-Ac-PABA), and the remaining 2-aminofluorene (AF) and p-aminobenzoic acid (PABA). The viability and NAT activity in a human colon tumor cell line was inhibited by berberine in a dose-dependent manner, i.e., the higher the concentration of berberine, the higher the inhibition of NAT activity and cell death. The NAT activities measured in the intact human colon tumor cells were decreased over 50% by AAF and NAc-PABA production from acetylation of AF and PABA. The apparent values of Kmoff and Vmax of NAT from colon tumor cells were also inhibited by berberine in cytosols and in intact cells. This report is the first to show that berberine did affect human colon tumor cell NAT activity.

Substantial decrease of heat-shock protein 90 precedes the decline of sperm motility during cooling of boar spermatozoa

The decline in boar semen quality after cryopreservation may be attributed to changes in intracellular proteins. Thus, the aim of the present study was to evaluate the change of protein profiles in boar spermatozoa during the process of cooling and after cryopreservation. A total of 9 sexually mature boars (mean age = 25.5+/-12.3 mo) was used. Samples for protein analysis were collected before chilling, after cooling to 15 degrees C, after cooling to 5 degrees C, following thawing after freezing to -100 degrees C, and following thawing after 1 wk of cryopreservation at -196 degrees C. Semen characteristics evaluated included progressive motility and the percentage of morphologically normal spermatozoa. Total proteins from 5x10(6) spermatozoa were separated and analyzed by SDS-PAGE. The results revealed that there was a substantial decrease of a 90 kDa protein in the frozen-thawed spermatozoa. Western blot analysis demonstrated that this protein was 90 kDa heat-shock protein (HSP90). Time course study showed that the decrease of HSP90 in spermatozoa initially occurred in the first hour during cooling to 5 degrees C. When compared with the fresh spermatozoa before chilling, there was a 64% decrease of HSP90 in spermatozoa after cooling to 5 degrees C. However, the motility and percentage of normal spermatozoa did not significantly decrease during this period of treatment. Both declined substantially as the semen was thawed after freezing from -100 degrees C. The results indicated that the decrease of HSP90 precedes the decline of semen characteristics. The length of time between a decrease of HSP90 and the decline in sperm motility was estimated to be 2 to 3 h. Taken together, the above results suggested that a substantial decrease of HSP90 might be associated with a decline in sperm motility during cooling of boar spermatozoa.

Effects of ibuprofen on arylamine N-acetyltransferase activity in human colon tumor cells

The inhibition of arylamine N-acetyltransferase (NAT) activity by ibuprofen was determined in a human colon tumour (adenocarcinoma) cell line. Two assay systems were employed, one with cellular cytosols (9000 g supernatant) and the other with intact colon tumour cell suspensions. The NAT activity in a human colon tumour cell line was inhibited by ibuprofen in a dose-dependent manner in both systems, i.e. the greater the concentration of ibuprofen in the reaction, the greater the inhibition of NAT activities in both systems. The data also indicated that ibuprofen decreases the apparent Km and Vmax of NAT enzyme from human colon tumour cells in both systems examined. This report is the first demonstration to show that ibuprofen affects human colon tumour cell NAT activity.

Effects of garlic compounds diallyl sulfide and diallyl disulfide on arylamine N-acetyltransferase activity in strains of Helicobacter pylori from peptic ulcer patients

Arylamine N-acctyltransferase (NAT) activities with p-aminobenzoic acid (PABA) and 2-aminofluorene (2-AF) were determined in the bacterium Helicobacter pylori collected from peptic ulcer patients. Two assay systems were performed, one with cellular cytosols, the other with intact cell suspensions. Cytosols or suspensions of H. pylori with or without specific concentrations of diallyl sulfide (DAS) or diallyl disulfide (DADS) co-treatment showed different percentages of 2-AF and PABA acetylation. The data indicated that there was decreased NAT activity associated with increased levels of DAS or DADS in H. pylori cytosols and suspensions. Viability studies on H. pylori demonstrated that DAS or DADS elicited dose-dependent bactericide affects on H. pylori cultures. The data also indicated that DAS and DADS decreased the apparent values of K(m) and Vmax of NAT enzyme from H. pylori in both systems examined. This report is the first demonstration that garlic components can affect H. pylori growth and NAT activity.

Dehydroepiandrosterone induces the transforming growth factor-beta production by murine macrophages

Dehydroepiandrosterone(DHEA), a predominant androgen secreted by the adrenal cortex, and dehydroepiandrosterone sulfate (DHEAS). Its predominant form in serum, were investigated for their role in the regulation of transforming growth factor-beta (TGF beta) production by murine macrophages. Using a bioassay based on the growing inhibition to Mv-1-Lu cells and RT-PCR analysis, the effect of DHEA and DHEAS on the TGF-beta production and gene expression was studied. Results suggested that DHEA at relatively high concentration (10 microM) significantly induced TGF-beta secretion by both peritoneal cells and P388D1 macrophage-like cells. For the cells treated with DHEAS, no significant increase in TGF-beta secretion was found statistically. Result of RT-PCR confirmed the observation that cDNA from the cells pretreated with DHEA generated a significant amount of amplicons but cDNA samples obtained from both control cells and DHEAS-treated cells showed relatively weak signals. In a quantitative RT-PCR analysis, both DHEAS-treated cells and control cells failed to compete with internal standards and failed to produce any detectable amplicons. Dexamethasone, one of the commonly used glucocorticoids, induced an increase in TGF-beta secretion and in mRNA level. Dexamethasone and DHEA failed to show a synergistic effect on the DHEA-induced increase in TGF-beta secretion and gene expression. The biological significance for DHEA to act as a positive stimulator for TGF-beta production and its role in glucocorticoid-mediated immunoregulation needs to be further delineated.

Effects of chronic lead exposure on [3H]MK-801 binding in the brain of rat

We have used quantitative autoradiographic methods to determine the effects of chronic lead exposure on N-methyl-D-aspartate (NMDA) receptors in the brain of female rat. Rats were exposed pre- and post-natally from day 4 +/- 1 post conception with 1000 ppm lead in their drinking water. This treatment continued after weaning. No effects of lead on [3H]MK-801 binding were found at PN 28. However, lead caused a significant increase in [3H]MK-801 binding in the hippocampus including CA1 and CA2, and in the occipital and temporal cortical areas at PN 56 and at PN 112. An increase in binding was also found in the entorhinal cortex and the dentate gyrus at PN 112. Because the NMDA receptor is involved in learning and memory, the lead-induced disruption of NMDA receptors in the hippocampus and cortex may be associated with the cation-induced cognition deficits.

Biodegradation of individual and multiple chlorinated aliphatic hydrocarbons by methane-oxidizing cultures

The microbial degradation of chlorinated and nonchlorinated methanes, ethanes, and ethanes by a mixed methane-oxidizing culture grown under chemostat and batch conditions is evaluated and compared with that by two pure methanotrophic strains: CAC1 (isolated from the mixed culture) and Methylosinus trichosporium OB3b. With the exception of 1,1-dichloroethylene, the transformation capacity (Tc) for each chlorinated aliphatic hydrocarbon was generally found to be in inverse proportion to its chlorine content within each aliphatic group (i.e., methanes, ethanes, and ethenes), whereas similar trends were not observed for degradation rate constants. Tc trends were similar for all methane-oxidizing cultures tested. None of the cultures were able to degrade the fully chlorinated aliphatics such as perchloroethylene and carbon tetrachloride. Of the four cultures tested, the chemostat-grown mixed culture exhibited the highest Tc for trichloroethylene, cis-1,2-dichloroethylene, tetrachloroethane, 1,1,1-trichloroethane, and 1,2-dichloroethane, whereas the pure batch-grown OB3b culture exhibited the highest Tc for all other compounds tested. The product toxicity of chlorinated aliphatic hydrocarbons in a mixture containing multiple compounds was cumulative and predictable when using parameters measured from the degradation of individual compounds. The Tc for each chlorinated aliphatic hydrocarbon in a mixture (Tcmix) and the total Tc for the mixture (sigma Tcmix) are functions of the individual Tc, the initial substrate concentration (S0), and the first-order rate constant (k/Ks) of each compound in the mixture, indicating the importance of identifying the properties and compositions of all potentially degradable compounds in a contaminant mixture.

Histopathologic alterations of periodontium in cyclosporin-treated rats. Is the periodontium a target tissue for the drug?

Gingival dimensions and histopathologic alterations in periodontium were examined in rats continuously exposed to cyclosporin-A (CSA). 60 male Sprague-Dawley rats were divided into 2 groups. Rats in the test group daily received CSA in mineral oil by gastric feeding at a dosage of 30 mg/kg body weight for 6 weeks. Rats in the control group received mineral oil only. 10 rats from each group were sacrificed at 2-week intervals. Gingival dimensions were assessed from stone models obtained from the maxillary and mandibular incisal regions. Horizontal, sagittal and frontal tissue sections were obtained from these regions as well. Gingival dimensions in the mandibular and maxillary incisal regions were significantly increased in rats exposed to CSA. Light-microscopic observations revealed a granulation tissue formation at tooth-gingiva interface and an irregular bony surface on dental alveoli in experimental animals. Because both soft and hard tissue of periodontium in experimental rats being significantly effected by CSA compared to control animals, we hypothesized that the periodontium is a target tissue for CSA.

Cyclosporin A-induced gingival overgrowth in rats: macroscopic and microscopic observations

Because the existence of cyclosporin A-induced gingival overgrowth in animals has not been well established, a pilot study was undertaken to determine whether such gingival overgrowth could be observed in Sprague-Dawley rats. Thirty-six male rats, age 6 weeks, were randomly divided into two groups. The test group was given 30 mg/kg of body weight of cyclosporin A daily by gastric feeding. The control group was given mineral oil instead. Stone casts of the gingiva in the mandibular incisor region were made biweekly for 6 weeks. The three-dimensional growth pattern-the buccolingual width, the mesiodistal width, and the vertical height of the gingiva-was analyzed on the casts. The animals were killed after the last impression was taken, and tissue sections were made. Stereomicroscopy revealed marked overgrowth of the gingiva in the test rats. All three-dimensional measurements on the stone casts were greater in the test group, beginning 2 weeks after cyclosporin A was given. Histologically the overgrowth of the epithelia and connective tissue was easily confirmed in the buccal and lingual gingiva of the test rats.

Specific Th1 cytokine down-regulation associated with primary clinically derived human immunodeficiency virus type 1 Nef gene-induced expression

HIV-1 infection is associated with a progressive and functional decline in the CD4+ lymphoid Th1 subset. Here, we propose that the HIV nef gene product may function as a specific regulator of Th1 cytokine production. By use of a T cell-specific inducible expression system, we show that upon T cell activation, induced nef expression down-regulated both IL-2 and IFN-gamma production in a dose-dependent manner, whereas IL-4, IL-9, IL-13, IL-8, and TNF-alpha production remained unaffected. In addition to this, independent transfected clones expressing various nef genes, including nef sequences amplified directly from an HIV-1 primary clinical isolate, displayed a similar pattern of cytokine expression. The specific Th1 impairment induced by nef, therefore, seems to be an important and conserved feature of HIV-1 infection and may represent a significant function of this viral gene in AIDS pathogenesis.

Specific Th1 cytokine down-regulation associated with primary clinically derived human immunodeficiency virus type 1 Nef gene-induced expression

HIV-1 infection is associated with a progressive and functional decline in the CD4+ lymphoid Th1 subset. Here, we propose that the HIV nef gene product may function as a specific regulator of Th1 cytokine production. By use of a T cell-specific inducible expression system, we show that upon T cell activation, induced nef expression down-regulated both IL-2 and IFN-gamma production in a dose-dependent manner, whereas IL-4, IL-9, IL-13, IL-8, and TNF-alpha production remained unaffected. In addition to this, independent transfected clones expressing various nef genes, including nef sequences amplified directly from an HIV-1 primary clinical isolate, displayed a similar pattern of cytokine expression. The specific Th1 impairment induced by nef, therefore, seems to be an important and conserved feature of HIV-1 infection and may represent a significant function of this viral gene in AIDS pathogenesis.

Relaxant effects of berberine on the rat fundus

The present study examines the relaxant effect of berberine on the longitudinal muscle of the isolated rat gastric fundus. Our experiments show that berberine reduces the tonic contraction more than the phasic contraction induced by carbachol. In addition, the carbachol induced phasic contraction in Ca+2 -free solution was only inhibited at the highest concentration of berberine. Berberine inhibited the slow phase more than the fast phase in KCl-induced contractions. These results suggest that the major mechanism of berberine consists of an inhibition of calcium entry from extracellular in the second phase induced by both carbachol and KCl. Conversely, prevention of the mobilization of store Ca+2 in the phasic contraction phase induced by carbachol and prevention of the calcium entry from extracellular in first phase elicited by high levels of potassium play only a minor role in the dilatory effect of berberine.

Dose-dependent gingival overgrowth induced by cyclosporin in rats

This study evaluated the effect of dosage on severity of cyclosporin-A (CSA) induced gingival overgrowth. Eighty (80) male Sprague-Dawley rats were randomly distributed into 4 groups. Rats in each group daily received CSA in mineral oil by gastric feeding at dosages of 0 (control), 3, 10, and 30 mg/kg, respectively, for 6 weeks. Stone models of the mandibular incisal region were obtained biweekly and were used for analysis of the gingival dimensions. Animals were sacrificed at the end of week 6 and tissue sections were processed for histopathologic evaluations. Animals were sacrificed at the end of week 6 and tissue sections were processed for histopathologic evaluation Gingival overgrowth including bucco-lingual and mesio-distal width and vertical height were significantly increased with increasing CSA dosage. Furthermore, the gingival dimensions displayed a positive linear relation to dosage and treatment duration. The histopathologic evaluation revealed a granulomatous tissue wedging the tooth-gingival interface in the 3 mg/kg group. This tissue had reached exuberant size in the 10 and 30 mg/kg groups. In summary, the analysis of gingival dimensions the histopathologic evaluation shows a dose-dependent effect on the severity of CSA-induced gingival overgrowth.

Changes in lymphocyte single strand breakage and liver function of workers exposed to vinyl chloride monomer

Vinyl chloride monomer (VCM) is a suspected human carcinogen. Its metabolite, chloroethylene epoxide, is able to alkylate the DNA molecule and to produce single strand breakage (SSB). A total of 244 workers from 4 polyvinyl chloride (PVC) manufacturing factories were recruited to assess the SSB of their peripheral lymphocyte DNA. The method of alkaline unwinding and hydroxyapatite chromatography was used to detect and calculate frequencies of SSB. In addition, hepatitis B and C markers and the liver function of the workers were also examined. The worker's cumulative exposures to VCM were retrospectively constructed from the current monitoring data and each worker's job history. Multiple linear regression models were constructed to predict the worker's level of SSB and liver functions based on various exposure indices and variables, such as age, sex, smoking, drinking, and hepatitis markers. The results showed that current smoking and drinking status, and the presence of VCM exposures on the previous day were 3 major determinants of the level of SSB. Among the liver function tests, only gamma-glutamyl transpeptidase (GGT) was associated with current VCM exposures. In contrast, aspartate aminotransferase (AST), alkaline phosphatase (ALP) and alanine aminotransferase (ALT) were mainly affected by the presence of hepatitis B surface antigen (HBsAg) or anti-hepatitis C virus (anti-HCV). We conclude that GGT should be considered to be included in the regular health screening of VCM workers, and that the SSB method may not be suitable for long-term monitoring of cumulative exposure because of the quick DNA repair mechanism in humans.

Gingival overgrowth induced by different dosages of cyclosporin in rats

BACKGROUND

The purpose of the study was to assess the dose effect on the severity of cyclosporin(CSA)-induced gingival overgrowth by an established rat model.

METHODS

A total of 60 Sprague-Dawley male rats which weights were about 250 gm were selected and randomly divided into four groups. Three experimental groups of rats were provided different gastric feedings of 3mg, 10mg, 30mg CSA per kilogram body weight, daily; the last group of rats was fed with mineral oil as the control. Stone impression models of the mandibular incisal region were taken and three-dimensional analyses of the overgrown gingiva were made biweekly.

RESULTS

In the 30 mg CSA-treated rats, all three-dimensional measurements of the gingiva were observed to be greater than those of the control rats from the second week after CSA administration. In the 10 mg CSA-treated rats, most of gingival measurements were found to be greater from the fourth week after CSA administration. The bucco-lingual width of interdental papilla on the sixth week after CSA administration was the only significant measurement showing a difference between the 3mg treated rats and the control group.

CONCLUSIONS

Because of a significant correlation between CSA-induced gingival overgrowth and CSA dosage, the dose effect on the severity of this gingival overgrowth was established in the rat model.

Increased transforming growth factor beta expression inhibits cell proliferation in vitro, yet increases tumorigenicity and tumor growth of Meth A sarcoma cells

Several observations correlate increased expression of transforming growth factor (TGF) beta 1 with tumorigenesis, suggesting that expression of this multifunctional growth factor may provide an advantage in tumor formation. However, many tumor cells are inhibited in their proliferation by TGF-beta in vitro, thus suggesting that TGF-beta synthesis could exert an antiproliferative effect on tumor formation. To evaluate the physiological relevance of increased TGF-beta 1 synthesis in such tumor cells which are strongly inhibited in their proliferation by TGF-beta, we chose Meth A sarcoma cells as a model system. We established cell clones overexpressing TGF-beta 1 and determined its effect on tumor formation in mice that are not immunocompromised. Increased expression of biologically active TGF-beta 1 resulted in a profound growth inhibition in the transfected clones and increased adhesiveness in vitro. However, these cells were much more tumorigenic than Meth A cells that did not overexpress TGF-beta 1, as assessed by both tumor incidence and tumor growth. In addition, parental Meth A cells were inhibited in their tumor formation by neutralizing TGF-beta antibodies and stimulated by exogenous TGF-beta. Our results thus provide evidence that increased TGF-beta synthesis provides a major advantage for tumorigenesis, even if the cells are growth inhibited by their endogenous TGF-beta synthesis in culture. These results suggest that, in vivo, direct effects of TGF-beta on the tumor environment, such as increased extracellular matrix formation and cell-matrix interactions, and local suppression of the immune surveillance may provide a growth advantage which overrules any direct antiproliferative effects of TGF-beta, as suggested by the effects in culture.

[Effect of spermidine on uptake of chloroquine by Plasmodium berghei]

To probe into the effect of spermidine on chloroquine (Chl) uptake by P berghei and its role of Chl-resistance, mice infected with Chl sensitive strain (CS) of P berghei were given Chl 20 mg.kg-1 ig combined with spermidine (Spe) 42 mg.kg-1 ip. It was found that 3 and 16 h after combined administration, Chl quantity uptaken by the parasites was reduced respectively by 59.6% and 53.8% in comparison with that in the Chl group. However, there was no difference in parasitaemia between Chl group (2.3 +/- 1.0) and Chl-Spe group (1.7 +/- 1.0), whereas the untreated control group remained a parasitaemia of 36 +/- 9. The authors deemed that Chl resistance is not merely attributed to the insufficient quantity of Chl in the Chl resistant parasites, the change in the sensitivity to Chl of Chl resistant parasites and the role of Spe in Chl resistance production should also be taken into consideration.