VUV photoabsorption of thermally processed carbon disulfide and ammonia ice mixtures - Implications for icy objects in the solar system.

Many icy bodies in the solar system have been found to contain a rich mixture of simple molecules on their surfaces. Similarly, comets are now known to be a reservoir of molecules ranging from water to amides. The processing of planetary/cometary ices leads to the synthesis of more complex molecules some of which may be the harbingers of life. Carbon disulphide (CS2) and ammonia (NH3) are known to be present on many icy satellites and comets. Reactions involving CS2 and NH3 may lead to the formation of larger molecules that are stable under space conditions. In this paper we present temperature dependent VUV spectra of pure CS2 in the ice phase, and of CS2 and NH3 ices deposited as (i) layered, and (ii) mixed ices at 10 K and warmed to higher temperatures until their sublimation. Pure CS2 ice is found to have a broad absorption in the VUV region, which is unique for a small molecule in the ice phase. In layered and mixed ices, the molecules tend to affect the phase change and sublimation temperature of each other and also leave behind a form of CS2-NH3 complex after thermal annealing. This study of CS2-NH3 ice systems in layered and mixed configurations would support the detection of these species/complexes in mixed molecular ices analogous to that on planetary and cometary surfaces.

Vacuum ultraviolet photoabsorption spectra of icy isoprene and its oligomers.

Isoprene and its oligomers, terpenes, are expected to be present, along with other complex organic molecules in the diverse environments of the ISM and in our solar system. Due to insufficient spectral information of these molecules at low temperature, detection and understanding the importance of these molecules has been rather incomplete. For this purpose, we have carried out the vacuum ultraviolet (VUV) photoabsorption measurements on pure molecular ices of isoprene and a few simple terpenes: limonene, α-pinene and ß-pinene by forming icy mantles on cold dust analogs. From these experiments, we report the first low temperature (10 K) VUV spectra of isoprene and its oligomers limonene, α-pinene and ß-pinene. VUV photoabsorption spectra of all the molecules reported here reveal similarities in the ice and gas phase as expected, with an exception of isoprene where a prominent red shift is observed in the ice phase absorption. This unqiue property of isoprene along with distinctive absorption at longer wavelengths supports its candidature for detection on icy bodies.

Influence of a 100-km ultra-marathon on hepatitis B carrier runners.

This study compares the serological markers between runners who are hepatitis B virus carries (HBVc) and runners who are non-HBVc in a 100-km ultra-marathon race. Blood samples of 8 HBVc and 18 non-HBVc runners were drawn 1 week before, immediately following, and 24 h after the race. Samples were analyzed and compared between the 2 groups for liver function tests, muscle damage markers and oxidative stress cytokines. For HBVc runners, HBV-DNA (hepatitis B virus-deoxyribonucleic acid) levels were also evaluated for virus reactivation. The results demonstrate a statistically significant increase in both immediate and 24-h post-race values for alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK), high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), compared with pre-race values. No statistically significant difference was observed between the 2 groups for the values of AST, LDH, CK, hs-CRP, IL-6 and TNF-α either before or after the race. There was also no statistically significant change in the levels of HBV-DNA in HBVc runners. These findings suggest that HBVc runners do not have higher risks of liver function impairment, muscle breakdown and inflammatory response compared to non-HBVc runners in such endurance races.

The reliability of data collection periods of personal costs associated with vision impairment.

PURPOSE: To determine the reliability of vision-related personal costs collected over 1, 3 and 6 months (extrapolated to 12 months) compared to one-year data. METHODS: Participants of any age, with a presenting visual acuity of < 20/40 in the better eye and an ability to converse in English, were recruited. Monthly cost diaries, in large print and electronic copies with instructions available in audio and Braille, were used prospectively to collect personal costs. The personal expenses were grouped under four categories, namely: (a) medicines, products and equipment, (b) health and community services, (c) informal care and support and (d) other expenses. Sociodemographic and clinical data were also collected. RESULTS: 104 participants (59 females) with a mean age of 64 years completed the 12-months diaries. Almost 40% of the participants had severe visual impairment (< 20/200) in the better eye and the most common cause of vision loss was AMD (n=40; 38%). The mean total personal costs collected from the 12-months diaries were 3,330+/-2,887 AUS dollars. There were no significant differences between the 12-months data and extrapolated 1, 3 and 6-months diaries (t-tests; p=0.17, 0.89 and 0.73, respectively). However, the 1-month variation was substantially larger (SD+/-5,860) compared to the 3-month and 6-month variances (SD+/-3,037 and 3,030, respectively) for total costs. Also, compared to the 12-months diaries, the 1-month data consistently recorded the weakest correlation coefficients for all cost categories compared to the other time intervals. CONCLUSIONS: Given that diary completion can be particularly challenging for individuals with impaired vision, a minimum 3-months data collection period can provide reliable estimates of annual costs associated with vision impairment.

Descending necrotising mediastinitis: a report of misdiagnosis as thoracic aortic dissection.

Descending necrotising mediastinitis is an uncommon disease in the emergency department. Early recognition is important for a good prognosis for this fatal condition. This report describes a case of a healthy 79 year old woman who was seen in the urgent care centre with the initial presentation of chest pain. Misdiagnosis was made because of the mis-reading of a flap-like artefact over the ascending aorta and difficulty interpreting subtle change of mediastinal soft tissue infiltration. The patient was then treated as dissecting aneurysm over ascending aorta until her condition deteriorated. Although aggressive treatment comprising thoracotomy, cervical incision and drainage, and antibiotics were begun, the response was poor. Emergency physicians should be familiar with this rare but highly lethal disease. Correlation should be made in a patient complaining about chest pain, especially combined with fever, sore throat, dysphagia, or neck swelling.

Human masticatory muscle activity and jaw position under experimental stress.

The purpose of the present study was to determine whether stress induced a consistent pattern of increased electromyographic (EMG) activity in different masticatory muscles, and whether stress produced changes in jaw position. Thirty-five dental students at Taipei Medical College volunteered for this study. Mental arithmetic was used to create a stress condition and relaxation instruction was used to help relax the subjects. Subjects were asked to evaluate the stress they felt under each experimental condition with a visual analogue scale (VAS). Surface electrodes were used to monitor the EMG activities of the right masseter, right posterior temporalis and suprahyoid muscles. A kinesiograph was used to observe the jaw position. Data collected before mental arithmetic or relaxation monitored the baseline level. The VAS means were significantly increased during the stress condition and significantly decreased following relaxation, compared with the baseline. There was also a significant increase in EMG activity of all three muscles during mental arithmetic compared with baseline; different patterns of increased EMG activity were noticed in the three muscles under a continuous stress condition. Under stress, the incidence of tooth contact at intercuspal position was also increased.

Preclinical evaluation of locoregional delivery of radiolabeled iododeoxyuridine and thymidylate synthase inhibitor in a hepatoma model.

UNLABELLED: We report improved incorporation of the radiolabeled-thymidine analog [125I/131I]5-iodo-2'-deoxyuridine ([125I/131I]IdUrd) into DNA by the addition of Thymitaq, a thymidylate synthase inhibitor, as a strategy of molecular radiotherapy for hepatoma treatment. METHODS: The synergistic effect of combination [125I]IdUrd and Thymitaq in clonogenic survival and DNA incorporation was shown on the human hepatoma cell line Hep3B. Radiobiodistribution of intrahepatic arterially injected [125I]IdUrd and Thymitaq was studied in a rat N1S1 hepatoma model. In vivo therapeutic effects of locoregional delivery of both drugs were evaluated in mouse subcutaneous hepatoma and ascitic hepatoma models. RESULTS: In a clonogenic assay, Thymitaq showed a synergistic effect with [125I]IdUrd but not cold IdUrd. Thymitaq had a dose-dependent modulation effect on DNA-[125I]IdUrd incorporation. The biodistribution study indicated a slower clearance rate of [125I]IdUdR in the hepatoma as well as an initially higher uptake of [125I]IdUrd into DNA when the [125I]IdUrd was combined with Thymitaq. In vivo studies showed a superior therapeutic effect of combination Thymitaq and [125I]IdUrd in both subcutaneous and ascites tumor models, but the combination of [131I]IdUrd and [125I]IdUrd may be more effective than Auger electron emitters alone for the treatment of subcutaneous tumor. CONCLUSION: The strategy of locoregional delivery of [125I/131I]IdUrd to a tumor site through an intrahepatic arterial, intratumoral, or intraperitoneal route in combination with Thymitaq is promising and may also have a favorable therapeutic index in vivo.

Haplotyping of mitochondrial DNA in the D-loop region by PCR: forensic application.

A rapid and simple method using restriction enzymes to detect the restriction fragment length polymorphism (RFLP) pattern of hypervariable segment 1 in the D-loop region of human mitochondrial DNA (mtDNA) was developed. We first focused on the investigation of variations of DNA sequence in the D-loop region among Chinese subjects, as well as on the determination of RFLP patterns of each restriction enzyme. Seven restriction enzymes were used to digest a 618 bp polymerase chain (PCR) reaction product of the D-loop region of mtDNA. Frequency distribution of RFLP patterns of each restriction enzyme among 145 unrelated Chinese subjects in Taiwan was also established. For the purposes of practical forensic application, a routine typing system was designed on the basis of the RFLP data. Two short hypervariable, mtDNA fragments, which were contained within the 618 bp region, were selected for this purpose. In this haplotyping system, a 281 bp PCR-amplified DNA product was analyzed by five restriction enzymes: Mnl I, Nla III, Rsa l, Mse I and Hinf I, and a 237 bp fragment was analyzed by Kpn I. The RFLP patterns were determined by agarose gel electrophoresis of the restriction enzyme-digested DNA fragments. Six restriction enzymes. Mul I, Nla III, Rsa I. Msc I, Hinf I and Kpn 1, defined eight, four, four, five, two and four polymorphic patterns, respectively among the 145 Chinese subjects. The RFLP patterns of restriction fragments for each individual were systematically analyzed and the mtDNAs of the 145 Chinese subjects were grouped into 52 haplotypes. This PCR-RFLP haplotyping system revealed a high degree of variability and diversity of segment I in the D-loop region of human mtDNA. The power of discrimination and allelic diversity values were 0.923 and 0.929, respectively. Successful application of this haplotyping system in a murder case is also discussed.

Prevention of false results from preferential PCR amplification or VNTR alleles.

In forensic DNA typing, evidential samples generally involve limited amounts of DNA and so should be carefully utilized. Although polymerase chain reaction (PCR) of variable number of tandem repeats (VNTR) alleles is the prevailing method for forensic identification, the fidelity of amplification of heterozygous VNTR alleles with large disparities in length needs to be carefully examined. Reports in the literature and our own observations have demonstrated that PCR artifacts, bogus alleles and allelic drop-out of VNTRs, are related to the amount of genomic DNA, the number of amplification cycles and the length of alleles amplified. Two small (< 1 kb) hypervariable VNTRs (Apo B and HVR-Ig) markers used for forensic identification were chosen to study these relationships. The results revealed that PCR amplification for the heterozygous VNTR alleles with wide disparity in length (> 400 bp) easily produced the allelic drop-out problem and therefore, led to the false results; and the allelic fragment of PCR products was preferentially lost after only 2 cycles of overamplification. We also further established the relationship between the optimal number of amplification cycles and the amount of genomic DNA in the reaction mixture. In our routine forensic screening this relationship has been successfully applied to determine the optimal number of amplification cycles and to avoid the allelic drop-out problem and achieve fidelity of PCR-VNTR amplification. It has also been used to investigate forensic casework.

Frequency distribution of hypervariable VNTRs in Apo B, HVR-Ig and COL2A1 loci in Taiwan: forensic application.

By use of a simple, rapid and reliable polymerase chain reaction (PCR)-based method, we analyzed three hypervariable tandem repeats in the 3'-Apo B, 5'-HVR-Ig and 3'-COL2A1 loci. As accurate data of allele frequency of genetic markers is a prerequisite for forensic application, the allele frequency distribution of the three variable number of tandem repeats (VNTR) among the Chinese population in Taiwan were studied. In a total of 123 unrelated Chinese subjects, the Apo B VNTR demonstrated a heterozygosity of 68.2% with 9 alleles, 0.85 of the power of discrimination (PD) value and 0.74 of the allelic diversity (h) value. In a sample of 103 unrelated Chinese subjects, the COL2A1 VNTR showed 49.0% heterozygosity with six alleles, 0.79 of the PD value and 0.74 of the h value. In 106 unrelated subjects, the HVR-Ig VNTR showed 47.4% heterozygosity with seven alleles, 0.79 of the PD value and 0.59 of the h value. The data obtained in this study are not only useful for forensic identification, but will also be helpful for paternity testing, genetic linkage studies and the identification of the three VNTR loci associated with human genetic diseases. Some verifying examinations for the validity and reliability of the three VNTR were performed. The high sensitivity and inexpensive nature of this approach make it superior to the traditional method of DNA fingerprinting for forensic typing. With the use of this PCR-VNTR system, many forensic cases have been successfully identified. The value of this system is illustrated in the investigation of a rape and murder case.

Flow chart HLA-DQA1 genotyping and its application to a forensic case.

The detection of genetic polymorphism has become increasingly important in forensic science as well as in medical genetics. In this report, we describe a systematic flow chart system for HLA-DQA1 genotyping by an improved PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) method coupled with the PRSM (PCR-mediated restriction site modification) method. This flow chart typing system can easily discriminate between a total of eight reported DQA1 alleles commonly found in Chinese. We have applied this flow chart typing system in a forensic case as well as in the determination of the frequencies of the eight DQA1 alleles in 121 unrelated Taiwan Chinese subjects. Our results show that the flow chart DQA1 genotyping is a simple, fast, and accurate system which, in the future, may be considered as an alternative method for routine individual identification in forensic casework, and for paternity testing and tissue typing in medical genetics.