The midgut epithelium of mosquitoes adjusts cell proliferation and endoreplication to respond to physiological challenges

BACKGROUND

Hematophagous mosquitoes transmit many pathogens that cause human diseases. Pathogen acquisition and transmission occur when female mosquitoes blood feed to acquire nutrients for reproduction. The midgut epithelium of mosquitoes serves as the point of entry for transmissible viruses and parasites.

RESULTS

We studied midgut epithelial dynamics in five major mosquito vector species by quantifying PH3-positive cells (indicative of mitotic proliferation), the incorporation of nucleotide analogs (indicative of DNA synthesis accompanying proliferation and/or endoreplication), and the ploidy (by flow cytometry) of cell populations in the posterior midgut epithelium of adult females. Our results show that the epithelial dynamics of post-emergence maturation and of mature sugar-fed guts were similar in members of the Aedes, Culex, and Anopheles genera. In the first three days post-emergence, ~ 20% of cells in the posterior midgut region of interest incorporated nucleotide analogs, concurrent with both proliferative activity and a broad shift toward higher ploidy. In mature mosquitoes maintained on sugar, an average of 3.5% of cells in the posterior midgut region of interest incorporated nucleotide analogs from five to eight days post-emergence, with a consistent presence of mitotic cells indicating constant cell turnover. Oral bacterial infection triggered a sharp increase in mitosis and nucleotide analog incorporation, suggesting that the mosquito midgut undergoes accelerated cellular turnover in response to damage. Finally, blood feeding resulted in an increase in cell proliferation, but the nature and intensity of the response varied by mosquito species and by blood source (human, bovine, avian or artificial). In An. gambiae, enterocytes appeared to reenter the cell cycle to increase ploidy after consuming blood from all sources except avian.

CONCLUSIONS

We saw that epithelial proliferation, differentiation, and endoreplication reshape the blood-fed gut to increase ploidy, possibly to facilitate increased metabolic activity. Our results highlight the plasticity of the midgut epithelium in mosquitoes' physiological responses to distinct challenges.

Life satisfaction and peace of mind among dentists: a cross-sectional study

OBJECTIVES

This study sought to identify the factors associated with the life satisfaction and peace of mind (PoM) of dentists not in full-time clinical training.

MATERIALS AND METHODS

Cross-sectional questionnaires were distributed to dentists in Taiwan to collect their life satisfaction, PoM, sociodemographic data, and dental career-related characteristics. Life satisfaction was measured using a 5-item Satisfaction with Life Scale. PoM was measured using a 7-item Peace of Mind Scale. Descriptive statistics and multiple linear regression models were estimated to explore potential associations between the two scales and the examined factors.

RESULTS

A total of 1196 dentists (45.6% female; mean age = 44.12) completed the questionnaires. The response rate of completed questionnaires from email invitations was 32.9%. On multivariable analysis, life satisfaction and PoM were associated with age (b = 0.008 in both), better perceived health (b = 0.262 and 0.308, respectively), family interaction (b = 0.264 and 0.207, respectively), and friend relationships (b = 0.076 and 0.091, respectively). Being married (b = 0.191), being specialized (b = 0.127), working in private practice, and spending 10 to 39 h per week with patients (b = 0.101 to 0.162) were associated with a higher level of life satisfaction but not PoM.

CONCLUSIONS

Specialists working in private practice without working overtime were associated with better life satisfaction. However, the dentists' health and relationships with family were more related to their subjective well-being than their professional achievements.

CLINICAL RELEVANCE

Our findings can help policymakers increase awareness of the well-being of general dentists and those in academia or hospitals to promote their mental health.

A multi-center study on recurrent inguinal hernias: assessment of surgeons' compliance to guideline-based repair and evaluation of short-term outcomes

INTRODUCTION

As patients with recurrent inguinal hernia (RIH) are at a higher risk of perioperative complications, international guidelines have been developed to mitigate these risks by recommending the reverse approach for repair. We aim to study the characteristics of RIH, compliance to guidelines-based repair (GR) and determine factors influencing compliance to guidelines.

METHODS

A retrospective study of patients with RIH was carried out at two tertiary institutions in Singapore, over 10 years from January 2010 to 2020.

RESULTS

There were 16 patients with bilateral recurrences and 214 patients with unilateral recurrences. The characteristics of patients with non-guidelines-based repair (NGR) versus GR were similar, p > 0.05. GR was performed for 128 (52.1%) hernias as compared to NGR for 118 (47.9%) hernias. The open approach was more common in NGR than GR, 115/118 (89.8%) versus 58/128 (45.3%), p < 0.001. Forty (n = 40, 16.3%) RIH presented emergently, of which 37 underwent NGR while 3 underwent GR, p < 0.0001. More consultants were present during GR 103/128 (80.5%) as compared to NGR 78/118 (66.1%), p = 0.018. Emergency presentation of hernia recurrence, OR 7.74 (CI 6.11-9.20), p = 0.005, and open repair during the index repair were significantly associated with NGR, OR 6.63 (CI 4.42-8.84), p = 0.01. Median length of stay was shorter in the GR 1 day (IQR 1-2 days) versus 2 days (IQR 2-5 days) in the NGR group, p = 0.02.

CONCLUSION

The compliance rate of GR for RIH is 52%. NGR for RIH had acceptable short-term outcomes. For elective presentation of RIH, GR should be encouraged given a shorter length of hospital stay.

[Survey on tobacco use and associated factors in population in Shandong province, 2016-2017]

Objective: To understand the status of tobacco use and related influencing factors in population in Shandong province. Methods: Stratified multi-stage cluster sampling was used to select respondents from 216 villages (communities) of 36 districts (counties) in Shandong province. Influencing factors on smoking were analyzed by logistic regression model. Results: The adequate sample size was 6 271 participants. After complex weighted, the current smoking prevalence was 23.93%,45.58% in males and 1.18% in females. The Public's smoking rates varied widely among different groups in the population. 45-64 age group had the highest smoking rate (25.07%). Smoking rates were substantially different in education levels, with the highest in junior high school (28.94%). The rate was higher in the rural area (24.98%) than that in the urban areas (23.08%). The average daily smoking rate was 20.23%. The average age of initiating smoking was 21.21 years. The average daily cigarette intake was 16.31 cigarettes. Among all the former and current smokers, the quitting rate was 20.79%. Multiple logistic regression model analysis showed that gender, age, occupation, region, and health knowledge score were correlated with smoking behavior. The current smoking rate of men was much higher than that of women (OR=49.625, 95%CI: 37.832-65.093). The current smoking rate in 45-64 age group was higher than that in the 15-24 age group (OR=1.830, 95%CI: 1.048-3.194). The current smoking rate of medical (OR=0.403, 95%CI: 0.187-0.866) and retired personnel (OR=0.648, 95%CI: 0.481-0.873) were lower than those engaging in agriculture, forestry, animal husbandry and the fishery ,respectively. The prevalence of residents living in the central part showed lower rate on current smoking than that in the eastern region (OR=0.724, 95%CI: 0.606-0.865). The current smoking prevalence of smoke hazard in 1-3 score group was higher than that in the group with 4-6 score (OR=1.432, 95%CI: 1.240-1.654). Conclusions: Smoking rate in adults in Shandong remained stable and at a high level. Comprehensive intervention measures such as tobacco control and health education should be carried out to reduce the smoking rate.

[Prevalence and associated factors regarding electronic cigarette smoking among adults in Shandong province]

Objective: To understand the awareness, current or past behavior on electronic cigarette smoking (ECS) and associated factors, among adults aged ≥15 years old in Shandong province. Relationship between ECS and cessation of smoking was also studied. Methods: Using the global standard questionnaire, a cross-sectional survey was conducted among 6 401 adults selected by stratified multi-stage cluster sample method. Electronic data was collected by handheld computer. Data were weighted and analyzed by SPSS 19.0 complex program. Results: The prevalence rates of awareness, ever or current smoking of e-cigarettes appeared as 37.6%, 3.8% and 0.6% respectively. Data from logistic regression analysis showed that risk factors for ECS were living in urban area, at younger age, being current or former cigarettes smoker and with knowledge on the risks of smoking or being encouraged to stop smoking. Among the electronic cigarettes smokers, those who tried to quit smoking (30.1%) had a significantly higher rate than that of the non-smokers (19.5%) (P<0.05), however, the successful quitting rate was much lower than that in the non-ECS users (P<0.05). Conclusions: Rates on the awareness and uptake of electronic cigarettes are on the rise. It is necessary to strengthen and standardize the monitoring programs to provide evidence for setting up targeting intervention strategies.

Life satisfaction of Taiwanese dental graduates received residencies in the U.S.: a cross-sectional study

BACKGROUND

Each year, more than 200 international dental graduates start U.S. specialty trainings to become specialists. It is unknown if their life satisfaction is associated with any dental career-related factor before residencies (e.g. dental school class rank, research experience, or private practice experience) and after residencies (e.g. staying in the U.S., teaching status, workplace, or board certification). This cross-sectional study aimed to identify these potential factors by surveying Taiwanese dental graduates who pursued U.S. residencies.

METHODS

Life satisfaction was measured with a structured questionnaire, Satisfaction With Life Scale (SWLS), which includes five statements on a 5-point Likert scale. Online surveys were sent out to 290 Taiwanese dental graduates who were known to pursue U.S. residencies. T-test, one way analysis of variance, and multivariable adjusted generalized linear model (GLM) were used to assess the differences of mean SWLS scores from different variables.

RESULTS

Surveys were completed by 158 dentists. Mean SWLS score of 125 specialists was higher (p = 0.0007) than the score of 33 residents. For the 125 specialists, multivariable adjusted GLM demonstrated better life satisfaction was positively associated with multiple independent factors, such as having research experience, being ranked in the top 26 ~ 50% of the class in dental school, starting U.S. residency within 4 years after dental school, starting residency before year 1996, and specializing in endodontics (vs. periodontics). Life satisfaction was not associated with any factors after residency (e.g. staying in the U.S. afterwards, teaching status, or workplace), but better mean life satisfaction score was significantly associated with being American specialty board certified (p < 0.001) for the specialists in the 26 ~ 75% of their class in dental school. For the 33 residents, better mean life satisfaction score was associated with better dental school class rank in both bivariate (p = 0.020) and multivariable adjusted GLM (p = 0.004) analyses.

CONCLUSIONS

The life satisfaction of Taiwanese dental graduates pursuing U.S. residencies might be associated with some professional factors, such as research experience, dental school class rank, residency timing, specialty type, and specialty board certification. We hope our results may provide some objective information on making career decisions for international dental graduates/students who are preparing for U.S. residency.

[Study on the relationship between smoking behavior and health literacy among grade 4-6 primary students in Shandong province]

Objective: To investigate the associations between smoking and literacy on health among 4-6 grade primary school students. Methods: A questionnaire survey was conducted to research on health literacy and smoking among 4-6 grade pupils in Shandong province, through a multi-stage stratified cluster random sampling method. Sociodemographic characteristics, health literacy level and smoking rate were collected from respondents. Binary logistic regression analysis was used to evaluate the association of smoking and health literacy. Results: A total of 9 240 questionnaires were distributed, with the rate of valid response as 99.7%. The current smoking rate of the students was 2.6%, on higher in boys (3.1%) than in girls (2.0%). 60.8% of 4-6 grade students were found to have adequate health literacy level. Levels of literacy health in both boy and girl school students appeared 56.7% and 64.9%, respectively. Results indicated that health literacy in smokers (14.4%) was lower than that in non-smokers (62.0%). Results from the binary logistic regression analysis showed that the independent influencing factors would include grade, father's education level, economic situation of the family, self-assessment on the school record and literacy on health (P<0.01). After controlling the other independent variables, the smoking rate was 8.62 (1/0.116) times in students with low literacy level on health, than those with high literacy level. Conclusions: Literacy on health was significantly associated with smoking in the 4-6 grade pupils of Shandong province.

Progress in Cr- and Mn-based superconductors: a key issues review

The presence of magnetic ions was first believed to be detrimental to superconductivity. However, unconventional superconductivity has been widely induced by doping or applying external pressure in magnetic systems such as heavy fermion, cuprate and iron-based superconductors in which magnetic fluctuations are suggested to serve as the pairing glue for Cooper pairs. The discovery of superconductivity in the magnetic compounds CrAs and MnP under high pressures has further expanded this family of superconductors and provided new platforms for investigating the interplay between magnetism and superconductivity. CrAs and MnP represent the first superconductors among the transition metal Cr- and Mn-based compounds in which the electronic states near the Fermi level are dominated by Cr/Mn 3d electrons. Shortly after their discovery, new types of Cr-based quasi-one-dimensional superconductors A₂Cr₃As₃ and ACr₃As₃ (A [Formula: see text] K, Rb, Cs or Na) were discovered at ambient pressure. The close proximity of superconductivity to magnetic instability in these systems suggests that spin fluctuations may play crucial roles in mediating the Cooper pairing. In this article we review the basic physical properties of these novel superconductors and the progress achieved in recent studies.

Interferon-gamma response to the treatment of active pulmonary and extra-pulmonary tuberculosis

BACKGROUND

Interferon-gamma (IFN-γ) release assays (IGRAs) are used to diagnose tuberculosis (TB) but not to measure treatment response.

OBJECTIVE

To measure IFN-γ response to active anti-tuberculosis treatment.

DESIGN

Patients from the Henan Provincial Chest Hospital, Henan, China, with TB symptoms and/or signs were enrolled into this prospective, observational cohort study and followed for 6 months of treatment, with blood and sputum samples collected at 0, 2, 4, 6, 8, 16 and 24 weeks. The QuantiFERON® TB-Gold assay was run on collected blood samples. Participants received a follow-up telephone call at 24 months to determine relapse status.

RESULTS

Of the 152 TB patients enrolled, 135 were eligible for this analysis: 118 pulmonary (PTB) and 17 extra-pulmonary TB (EPTB) patients. IFN-γ levels declined significantly over time among all patients (P = 0.002), with this decline driven by PTB patients (P = 0.001), largely during the initial 8 weeks of treatment (P = 0.019). IFN-γ levels did not change among EPTB patients over time or against baseline culture or drug resistance status.

CONCLUSION

After 6 months of effective anti-tuberculosis treatment, IFN-γ levels decreased significantly in PTB patients, largely over the initial 8 weeks of treatment. IFN-γ concentrations may offer some value for monitoring anti-tuberculosis treatment response among PTB patients.

[The analysis of clinical characteristics and disease activity in ankylosing spondylitis patients with hyperuircemia]

Objective: to investigate the clinical characteristics and disease activity in ankylosing spondylitis (AS) patients with hyperuricemia. Method: Laboratory tests, magnetic resonance imaging, disease activity and functional index of AS patients from Fudan University Zhongshan Hospital were collected. T test, square test were applied to investigate the difference between AS patients with hyperuricemia and AS patients with normal serum uric acid in clinical characteristics and disease activity in AS patients. Result: Among all the AS patients, 23.4% (22/94) patients accompanied with hyperuricemia. AS patients accompanied with hyperuricemia showed significant younger age (28.9±7.9 vs 35.8±11.1, P=0.002); higher serum alanine aminotransferase (33.6±23.6 vs 19.8±12.4, P=0.014), aspartate aminotransferase (23.8±8.7 vs 18.6±9.6, P=0.025) and creatinine (78.4±12.5 vs 69.8±13.3, P=0.009), lower Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) (11.2±8.8 vs 17.9±12.0, P=0.027) and Bath Ankylosing Spondylitis Functional Index (BASFI) (0.7±0.9 vs 1.8±2.2, P=0.002) compared with AS patients whose serum uric acid level is normal. Conclusion: AS Patients with younger age, impaired hepatic and renal funtion and lower scores in BASDAI and BASFI tend to accompany with hyperuricemia.

Revealing Extremely Low Energy Amplitude Modes in the Charge-Density-Wave Compound LaAgSb_{2}

Using infrared spectroscopy and ultrafast pump probe measurement, we have studied the two charge-density-wave (CDW) instabilities in the layered compound LaAgSb_{2}. The development of CDW energy gaps was clearly observed by optical spectroscopy, which removed most of the free carrier spectral weight. More interestingly, our time-resolved measurements revealed two coherent oscillations that softened by approaching the two phase transition temperatures, respectively. We addressed that these two oscillations come from the amplitude modes of CDW collective excitations, the surprisingly low energies (0.12 THz and 0.34 THz for the higher and lower temperature ones, respectively) of which are associated with the extremely small nesting wave vectors. Additionally, the amplitude and relaxation time of photoinduced reflectivity of LaAgSb_{2} single crystals stayed unchanged across the CDW phase transitions, which is quite rare and deserves further investigation.

Infrared properties of heavy fermions: evolution from weak to strong hybridizations

In this article, we review the charge excitations of heavy fermion compounds probed by infrared spectroscopy. The article is not meant to be a comprehensive survey of experimental investigations. Rather it focuses on the dependence of charge excitations on the hybridization strength. In this context, the infrared properties of the Ce m M n In3m+2n family are discussed in detail since the hybridization strengths differ dramatically in different members despite their similar lattice structures. Investigations on some mixed valent compounds are also presented, aiming to elucidate the generic trend of the evolution. In particular, we address the scaling between hybridization energy gap [Formula: see text] and hybridization strength [Formula: see text]([Formula: see text]) in a wide range of heavy fermion compounds, which demonstrates that the periodic Anderson model can generally and quantitatively describe the low-energy charge excitations.

Magnetoinfrared Spectroscopy of Landau Levels and Zeeman Splitting of Three-Dimensional Massless Dirac Fermions in ZrTe(5)

We present a magnetoinfrared spectroscopy study on a newly identified three-dimensional (3D) Dirac semimetal ZrTe(5). We observe clear transitions between Landau levels and their further splitting under a magnetic field. Both the sequence of transitions and their field dependence follow quantitatively the relation expected for 3D massless Dirac fermions. The measurement also reveals an exceptionally low magnetic field needed to drive the compound into its quantum limit, demonstrating that ZrTe(5) is an extremely clean system and ideal platform for studying 3D Dirac fermions. The splitting of the Landau levels provides direct, bulk spectroscopic evidence that a relatively weak magnetic field can produce a sizable Zeeman effect on the 3D Dirac fermions, which lifts the spin degeneracy of Landau levels. Our analysis indicates that the compound evolves from a Dirac semimetal into a topological line-node semimetal under the current magnetic field configuration.

Administrative trends in U.S. dental schools

The aims of this study were to analyze the administrative trends in U.S. dental schools at the beginning and end of a thirteen-year period and to identify the predictive factors for those changes. Administrative trends were measured by the difference in the number of major administrative positions for 1997 and 2010 reported in American Dental Education Association (ADEA) and American Dental Association (ADA) publications. Secondary measures (program length, student enrollment, and tuition) were also gathered. The mean numbers of administrative positions per school significantly increased over the study period, while the mean number of clinical science departments per school significantly decreased. The change in the number of directors was positively correlated with the change in student enrollment, but inversely correlated with the change in number of vice/associate/assistant deans. The change in the number of clinical science departments was positively correlated with changes in student enrollment and out-of-state tuition, but inversely correlated with the change in in-state tuition. The number of all departments per U.S. dental school significantly decreased in this period. The schools that had consolidation of clinical science departments were less likely to have increases in student enrollment and out-of-state tuition, but more likely to have increases in in-state tuition.

Disposable plasmonic plastic SERS sensor

The 'Klarite™' SERS sensor platform consisting of an array of gold coated inverted square pyramids patterned onto a silicon substrate has become the industry standard over the last decade, providing highly reproducible SERS signals. In this paper, we report successful transfer from silicon to plastic base platform of an optimized SERS substrate design which provides 8 times improvement in sensitivity for a Benzenethiol test molecule compared to standard production Klarite. Transfer is achieved using roll-to-roll and sheet-level nanoimprint fabrication techniques. The new generation plastic SERS sensors provide the added benefit of cheap low cost mass-manufacture, and easy disposal. The plastic replicated SERS sensors are shown to provide ~10(7) enhancement factor with good reproducibility (5%).

Effect of cyclosporine-A on orthodontic tooth movement in rats

OBJECTIVE

The objective of this study is to examine the effect of cyclosporine-A (CsA) on the rate of orthodontic tooth movement in rats.

SETTING AND SAMPLE POPULATION

This is a randomized controlled trial with a split-mouth design in Sprague-Dawley rats.

MATERIAL AND METHODS

Eighteen rats, divided at random in two groups, were fed with 8 mg/kg CsA (experiment) or mineral oil (control) daily after initial healing of bilateral maxillary second molar removal. All rats received orthodontic coil springs (10 cN) secured to the maxillary incisors and first molars at the rights side, while no springs were placed at the left. Distances between first and third molars were measured on days 0, 3, 6, and 12. After sacrificing on day 12, the alveolar ridges of the maxillae were sectioned and blood samples were collected for serum tartrate-resistant acid phosphatase (TRAP)-5b level detection and for histology, respectively.

RESULTS

Significantly larger changes in intermolar distances were found after orthodontic force application in the CsA group at days 3 and 12 when compared with the control group. The inter-radicular dental alveolus of CSA-fed rats was osteopenic. Significantly increased TRAP-5b serum level was noted in the CsA group when compared with the control group.

CONCLUSIONS

We suggest that CsA enhanced the rate of orthodontic tooth movement. The osteopenia and the increased osteoclastic activity could be the underlying factors.

Biopsy forceps is inadequate for the resection of diminutive polyps

BACKGROUND AND STUDY AIMS

Cold biopsy forceps polypectomy (CBP) is often used for the removal of diminutive polyps. The efficacy of the technique has not been thoroughly assessed. The aim of this study was to prospectively assess the efficacy of CBP for removing diminutive polyps.

PATIENTS AND METHODS

This was a prospective study from St Vincent's Hospital, a tertiary referral hospital in Melbourne, Australia. A total of 143 patients were screened and 52 patients with ≥ 1 diminutive polyps were enrolled. CBP was used to resect diminutive polyps until no polyp tissue was visible. The polyp base was then resected using endoscopic mucosal resection (EMR) with a 1 - 2-mm margin. The CBP and EMR samples were compared to assess completeness of the resection.

RESULTS

Overall 39 % (21 / 54) of diminutive polyps were completely resected using CBP. After binary logistic regression analysis, polyp histology was found to be predictive of resection, with complete resection of 62 % (13 / 21) for adenomas and 24 % (8 / 33) for hyperplastic polyps (odds ratio 5.1; P = 0.008). The size and number of bites taken with the forceps were not predictive of complete response.

CONCLUSIONS

Within the limitations of a modest sample size, CBP appears to be inadequate treatment for the removal of diminutive polyps.

Two new mutations in the keratin 4 gene causing oral white sponge nevus in Chinese family

OBJECTIVE

We investigated white sponge nevus (WSN) in a Chinese family, and tried to find new mutation and demonstrated that this mutation is the causative mutation for WSN in this family and this condition affects a functionally important segment of the keratin 4 protein.

MATERIALS AND METHODS

We studied the affected family with the 32-year-old female patient, her mother, her younger sister and her daughter. Pathologic examinations were performed. DNA was extracted from peripheral blood lymphocytes, K4 and K13 genes were amplified by polymerase chain reaction (PCR) and sequenced.

RESULTS

Direct sequencing of PCR products revealed two new mutations in the keratin 4 gene, the heterozygous missense mutation 1829G-->A in exon 2B, and 2324A-->G in non-coding region. No any mutation was found in the keratin 13 gene.

CONCLUSIONS

We found two new mutations in the keratin 4, which may be related with the development of WSN.

Synthesis and biological evaluation of novel naphthoquinone fused cyclic aminoalkylphosphonates and aminoalkylphosphonic monoester

A series of novel naphthoquinone fused cyclic alpha-aminophosphonates, 2-alkoxy-3,4-dihydro-2H-naphtho[2,3-e][1,4,2]oxazaphosphinane-5,10-dione 2-oxide 3-17 and naphthoquinone fused cyclic alpha-aminophosphonic monoester 18 were synthesized for the first time. These cyclic alpha-aminophosphonates were evaluated for antitumor activity on four human tumor cell lines, and three of them showed significant cytotoxicity (IC(50): 0.019-5.15 microM) comparable to that of the reference drug doxorubicin. Furthermore, inhibition assays for topoisomerase II-mediated relaxation of supercoiled DNA indicated that the naphthoquinone fused cyclic aminophosphonates were catalytic inhibitors of topoisomerase II.

The accuracy of EUS-FNA in assessing mediastinal lymphadenopathy and staging patients with NSCLC

Optimal management of nonsmall cell lung cancer (NSCLC) depends on tissue diagnosis and accurate staging. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is minimally invasive and provides cytological confirmation of malignant mediastinal disease. The aim was to assess the accuracy of EUS-FNA in cases of enlarged mediastinal lymphadenopathy (LN) of unknown aetiology and in the staging of NSCLC. A total of 52 consecutive patients with stage I-IIIb NSCLC or enlarged mediastinal LN of unknown aetiology underwent EUS-FNA. Negative results were confirmed with a surgical procedure: mediastinoscopy, video-assisted thoracic surgery (VATS) or lobectomy with systematic mediastinal lymph node dissection. In total, 34 patients had EUS-FNA performed for diagnosis, whilst the remaining 18 had EUS-FNA for staging. The overall sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy (95% confidence interval) were 93% (77-99), 100% (78-100), 100% (87-100), 88% (63-99) and 95% (84-99), respectively. When EUS-FNA was used in patients with NSCLC, the sensitivity, specificity, PPV, NPV and accuracy were 92% (73-99), 100% (69-100), 100% (85-100), 83% (51-98) and 94% (80-99), respectively. For mediastinal LN of unknown aetiology, no malignant disease was missed. Endoscopic ultrasound-guided fine-needle aspiration is an accurate tool for assessing mediastinal lymph node involvement in nonsmall cell lung cancer and in the diagnosis of unexplained mediastinal lymphadenopathy. Endoscopic ultrasound-guided fine-needle aspiration is a minimally invasive procedure that can be used as an adjunct or alternative to mediastinoscopy.

Chronic hepatitis B: recommendations for therapy based on the natural history of disease in Australian patients

BACKGROUND

Chronic hepatitis B infection (CHB) is a major health problem in Australia and worldwide. CHB is associated with significant long-term morbidity and mortality. Well tolerated treatment is now available, however the development of resistance is common and the optimal timing of treatment is yet to be determined. Identifying the factors that influence the natural history of CHB may help determine which patients need treatment and when to start it.

OBJECTIVE

To determine the demographics, clinical features and virological profile of Australian patients infected with CHB and the influence of these factors on disease activity and severity.

STUDY DESIGN

Review of prospectively collected demographic, clinical and virological features of all patients positive for hepatitis B surface antigen (HBsAg) for more than 6 months who were referred to St. Vincent's Hospital liver clinics. Age, sex and ethnicity were correlated with hepatitis B e antigen status (HBeAg), HBV replication status (ALT and HBV DNA), genotype and liver histology.

RESULTS

703 chronic hepatitis B surface antigen positive patients were identified. The patients were predominantly male with an average age of 44. Eighty two percent of patients were born overseas, primarily from Asian (65%) and Mediterranean countries (14%). Two thirds (426) had an elevated ALT (median 79) at presentation. HBeAg was positive in 37%. Active viral replication, defined as abnormal ALT or positive HBVDNA, was present in 74%, 48% of whom were HBeAg negative. In a subset of 103 patients genotyped, 8% had genotype A, 29% B, 41% C and 22% D. Genotype correlated with ethnicity; patients infected with genotypes A were predominantly Caucasian, B and C were Asian, and D were Mediterranean. Of 296 (42%) patients who underwent liver biopsy, 76 (27%) had advanced fibrosis. Advanced fibrosis was associated with increasing age and Mediterranean ethnicity.

CONCLUSION AND RECOMMENDATIONS

Perinatal or early childhood transmission is predominant mode of infection in Australia. Two thirds of this cohort had active replication and were at increased risk of developing cirrhosis and/or hepatoma. Advanced disease was associated with age and ethnicity. HBeAg negative CHB accounts for almost half of all those with active viral replication. This parallels the rise in this form of CHB in Asia and the Mediterranean basin. Screening should be offered to people born in, or with parents born in areas of high endemnicity. To detect the development of active disease, patients with positive HBsAg but normal ALT should have liver function tests done 6 monthly and those with elevated ALT should be referred for consideration of therapy, irrespective of HBeAg status.

Stroke audit

Medical audit is vital to ensure continuous quality assurance and quality improvements. We did a retrospective study to ascertain the adequacy of clinical documentation and the factors hindering early discharge after an acute stroke in a restructured hospital. The medical records of all patients with acute stroke who died or were discharged from a restructured hospital in Singapore in January and February 1999 were reviewed retrospectively. Demographic data and the presence or absence of clinical documentation were noted. Factors hindering the discharge of patients at Day 5, Day 10 of stroke and at final discharge were noted and classified into: stroke-related, complications of stroke, medical-related and social factors. There were 101 patients in the study cohort, 55 males (54.5%) and 46 females (45.5%). The mean age was 67.9 years (SD 12.3). Documentation in Barthel scores (0%), presence of depression (0%), mental scores (1.0%), visual problems (10.0%), bladder continence (39.6%), admission functional status (37.6%) and dysphagia (52.5%) were deficient. The mean length of stay (LOS) was 13.0 (SD 14.2) days. The main factor hindering discharge at Day 5 (90.4%), Day 10 (95.2%) and at final discharge (82.1%) was stroke-related problems. Poor function (60.3%) and dysphagia (15.8%) were the 2 most common stroke-related problems hindering final discharge. Complications of stroke, medical-related problems and social reasons hindered final discharge in 10.8%, 17.8% and 2.9% of patients respectively. This audit revealed inadequacy in clinical documentation in patients with acute stroke. The main hindrance to final discharge of patients was stroke-related problems. The 2 most important stroke-related problems were poor function and dysphagia.

No association between T102C polymorphism of serotonin-2A receptor gene and clinical phenotypes of Chinese schizophrenic patients

Serotonin dysfunction has been implicated in the pathogenesis of schizophrenia. Previous studies have shown an association between the T102C polymorphism of the 5HT2a receptor gene and schizophrenia. However, negative findings have also been reported. One possible explanation for such discrepancy is disease heterogeneity due to the current limitations in the diagnosis of schizophrenia. We conducted a case-control study of the T102C polymorphism with detailed characterisation of the clinical phenotypes to investigate the possible association with schizophrenia not only at the diagnostic level, but also with reference to other clinical phenotypes potentially related to serotonin dysfunction. Four hundred and seventy-one biologically unrelated schizophrenic patients and 523 unrelated healthy controls of Han Chinese descent in Hong Kong were compared for genotypes and allele frequencies of the T102C polymorphism by PCR amplification and restriction analysis. No evidence of association was detected at the diagnostic level and various clinical phenotypes. However, we found a trend association with small effect size between genotype 102T/102C and patients with better verbal fluency and less motor co-ordination soft neurological signs. There is a need for future large-scale studies on the possible associations between genetic polymorphisms and neurocognitive function impairments in schizophrenia.

Five new diprenylated flavonols from the leaves of Broussonetia kazinoki

Five new diprenylated flavonols, broussonol A (1), broussonol B (2), broussonol C (3), broussonol D (4), and broussonol E (5), along with two known compounds, were isolated from an ethanolic extract of the leaves of Broussonetia kazinoki. Their structures were elucidated by chemical and spectral methods. Cytotoxic activities were evaluated against several different cell lines.

Neurological signs and sustained attention impairment in schizophrenia

Both neurological signs and attention impairments are often found in schizophrenia. This study addresses the extent to which neurological signs are related to sustained attention impairment. We assessed subgroups of neurological signs using the standardised Cambridge Neurological Inventory (CNI). Sustained attention was measured using a monotone counting paradigm. After taking into consideration potential confounds such as age, education level and duration of illness, we explored the correlation between sustained attention and groups of neurological signs, as well as with individual signs. We found that "motor coordination" and "disinhibition" signs were significantly related to sustained attention. The correlation with "sensory integration" just failed to reach significance after correction for multiple comparison. "Dyskinesia", "catatonia", "pyramidal" and "extrapyramidal" subgroups were unrelated to sustained attention. The results support the notion of heterogeneity and diversity in neurological signs (even among soft neurological signs) and argue against the use of a single global measure to embrace all soft neurological signs in schizophrenia.

Two new bislabdane-type diterpenoids and three new diterpenoids from the roots of Cunninghamia lanceolata

Two new bislabdane-type diterpenoids lanceolatin (1), lancelatol (2) and three new diterpenoids 15-nor-14-oxo-8(17),12-labdanien-14,18-dionic acid (3), 8(17),12,14-labdantrien-18-oic acid (4) and 8(17),12,14-labdantrien-18-ol (5), together with 7 known diterpenoids were isolated from the roots of Cunninghamia lanceolata. Their structures were determined by spectroscopic and chemical methods. All of these compounds were isolated from the species for the first time. One of the isolated compounds showed a significant inhibition effect on mouse hind-paw edema induced by carrageenan.

Stroop interference and facilitation effects in first-episode schizophrenic patients

In the Stroop test, interference occurs in naming the print color of a word when the word is itself the name of another color. Facilitation occurs when the word is the same as the print color. Previous studies on selective attention in schizophrenia using the Stroop interference effects have yielded contradicting results. Constraints included limited sample size and the recruitment of medicated chronic patients. We studied the Stroop interference and facilitation effects in a relatively large sample of first-episode schizophrenic patients (n=56), a substantial proportion of whom were medication-naïve (n=30) at the time of initial testing. We have also carried out longitudinal follow-up assessments when patients reached a clinically stable state, as well as 4months after recovery from the episode. We found that the Stroop interference effect was not increased in first-episode schizophrenic patients, whether medication-naïve or not. This effect did not change over the follow-up period. In addition, we detected an increase in Stroop facilitation effect in medicated schizophrenic patients, but only in the initial assessment soon after they had received medication. After sustained treatment, the increase in facilitation was normalized. These observations supported previous findings of a normal Stroop interference effect amongst schizophrenic patients. The increased facilitation effect for patients in their early phase of treatment (but not later) may represent an acute effect of anti-psychotic medication. Its nature and significance require further investigation.

Use of an overtube for enteroscopy--does it increase depth of insertion? A prospective study of enteroscopy with and without an overtube

BACKGROUND AND STUDY AIMS

Although a stiffening overtube is commonly used with push enteroscopy, in the belief that this will allow increased insertion into the small intestine, there is no prospective data to support this view. The aim of this study is to prospectively study the depth of insertion into the small intestine at enteroscopy with and without an overtube.

PATIENTS AND METHODS

A total of 38 patients referred for enteroscopy were prospectively studied. Alternate enteroscopies were performed with or without an overtube; therefore 19 patients had enteroscopy with and 19 without an overtube. The groups were well matched for age, sex, indication, use of fluoroscopy, and dedicated anesthetic assistance. Depth of insertion was assessed by advancing the enteroscope as far as possible, then straightening the enteroscope until the tip began withdrawing. The difference between the straightened insertion depth and the distance from the incisors to the pylorus was recorded as the insertion depth beyond the pylorus. This was considered the major end point. Statistical analysis was performed using the Mann-Whitney test for nonparametric data.

RESULTS

The median straightened total insertion depth from the incisors was greater when enteroscopy was performed with an overtube compared with enteroscopy without an overtube (125 cm vs. 110 cm, P=0.05). The median straightened insertion depth beyond the pylorus was significantly greater with overtube use (70 cm vs. 50 cm, P = 0.01). No significant difference between the groups was observed in terms of the likelihood of significant findings at enteroscopy.

CONCLUSIONS

Use of an overtube for push enteroscopy results in significantly deeper insertion into the small intestine. Although a larger study would be needed to demonstrate an increase in diagnostic yield and to confirm the safety of overtube use, this study does provide the first objective evidence of an advantage in terms of insertion depth.

Chemical constituents from the leaves of Magnolia denudata

20 compounds were isolated from the leaves of Magnolia denudata including 16 lignans, which belong to 6 structural types. Except for (7R, 8S, 1'S)-delta8' -1', 4'- dihydro-5'-methoxy-3,4-methylenedioxy-4'-oxo-7.0.2', 8.1'-neolignan (6), magliflonenone (9), 2, 5'-diene-2', 8'-epoxy-5'-methoxy-8-methyl-4'-oxo-3,4- methylenedioxy-spiro (5, 5)-undecane (10), veraguensin (16) and beta-sitosterol (20), the other 15 compounds were obtained from this species for the first time. The absolute configurations of 3 compounds (1, 4, 10) were determined by CD spectroscopy for the first time. The anti-inflammatory activities of compounds 1, 2 and 16 were assessed and 2 was shown to have significant inhibition effect on mice hind-paw edema induced by carrageenan.

Insight changes in acute psychotic episodes: a prospective study of Hong Kong Chinese patients

Insight impairment occurs commonly in psychotic disorders (including mood episodes with psychotic symptoms). The aim of the present study is to measure changes of insight over the course of a psychotic episode and to investigate its relationships with symptoms and neurocognitive functions, as well as psychosocial factors. Insight was assessed at weekly intervals in 80 consecutive inpatients presenting with a psychotic episode by using a Chinese translation of the Scale to Assess Unawareness of Mental Disorder (SUMD). The relationships between insight change and other variables were explored. Modest but significant changes in insight were found in both directions with clinical resolution of psychotic symptoms. In particular, insight "declined" as symptoms improved in a number of patients. In addition, changes in insight score correlated with changes in Wisconsin Card Sorting Test (WCST) performance. More changes in insight (in either direction) tended to occur in younger patients. These results indicated that adequate control of psychotic symptoms and improvement in neuropsychological functioning might be associated with better insight recovery.

Structures of two new benzofuran derivatives from the bark of mulberry tree (Morus macroura Miq.)

Two new benzofuran derivatives, macrourins A (1) and B (2), together with two known stilbene derivatives, were isolated from the barks of Morus macroura Miq. Their structures were elucidated by means of spectroscopic evidence.

Results of laparoscopic fundoplication where atypical symptoms coexist with oesophageal reflux

BACKGROUND

Laparoscopic Nissen fundoplication (LNF) has been increasingly performed for gastro-oesophageal reflux disease. The outcomes of LNF for patients with concurrent symptoms other than heartburn are unclear. The purpose of the present paper was to review the outcomes of LNF performed by one surgeon over 4 years and compare the outcomes of patients with reflux symptoms with those of patients having reflux symptoms plus atypical symptoms.

METHODS

The records of a consecutive series of 90 patients were reviewed. Preoperative symptoms were defined as typical (heartburn and reflux) or atypical (other symptoms, e.g. cough, atypical chest pain, choking). At the time of follow up an independent observer interviewed patients, and collected data on current symptoms and patient satisfaction. A questionnaire of current symptoms and patient satisfaction was completed. A satisfaction score from 1 to 10 was given by patients, with 1 being very unsatisfied and 10 being very satisfied.

RESULTS

Of the 90 patients, 97% had typical symptoms and 56% had concurrent atypical symptoms. Eighty-three of 90 patients were contacted; typical reflux symptoms improved in 95% of patients whereas atypical symptoms improved in only 54%. Overall, the mean satisfaction score was 8.7. Patients with atypical symptoms had a lower satisfaction score of 8.0 versus a satisfaction score of 9.0 for patients with only typical symptoms (P < 0.05). Patients with a satisfaction score < 8.0 had a higher rate of atypical symptoms (75%) than patients with a satisfaction score > or = 8 (50%).

CONCLUSION

Laparoscopic Nissen fundoplication controlled typical reflux symptoms very well but atypical symptoms were improved in only approximately 50%. A lower satisfaction score was associated with preoperative atypical symptoms.

Progressive deterioration of soft neurological signs in chronic schizophrenic patients

OBJECTIVE

Neurological signs are found to be increased in schizophrenia in cross-sectional studies. Whether they progress with time is an important issue in addressing the course of the illness.

METHOD

The current study investigated different groups of neurological signs in 43 stable chronic schizophrenic patients over a 3-year period using an operationalized instrument.

RESULTS

While symptoms and medication have remained largely unchanged in the 3-year period, significant increase in soft neurological signs (SNS) ('motor coordination', 'sensory integration' and 'disinhibition') has been observed. This contrasted with the stability of 'pyramidal', 'extrapyramidal', 'dyskinesia' and 'catatonia' signs. The increase in SNS appears not to be related to age, illness duration, symptoms or medication.

CONCLUSION

This finding suggests that SNS represent a marker sensitive to a possible late deterioration process in the course of a schizophrenic illness.

[Studies on the chemical constituents of Murraya kwangsiensis]

AIM

To investigate the chemical constituents of Murraya kwangsiensis.

METHODS

Compounds were isolated by silica gel column chromatography and TLC method, respectively. Structures of compounds were elucidated by spectral (UV, IR, MS, 1HNMR and 13CNMR) analysis.

RESULTS

Five carbazole alkaloids and two other compounds were isolated and identified. Six of them are known compounds: murrayafoline A, murrayanine, koenine, isomahanine, palmitic acid and beta-sitosterol. One is a new alkaloid, named kwangsine.

CONCLUSION

A new alkaloid, named kwangsine, was isolated from Murraya kwangsiensis Var. Six known compounds were isolated from this plant for the first time.

A five-year longitudinal study of the regional cerebral metabolic changes of a schizophrenic patient from the first episode using Tc-99m HMPAO SPECT

This is a naturalistic study of the relationship between cerebral metabolic activity, clinical symptoms and treatment response in a schizophrenic patient for 5 years from the onset of her illness. Serial technetium-99m-HMPAO brain SPECT was used to measure regional cerebral metabolism. The Cambridge Neurological Inventory and neuropsychological tests (WAIS-R verbal subscales, Wisconsin Card Sorting Test, semantic verbal fluency, logical memory in Weschler Memory Scale) were used for neurocognitive assessment. Under-activity of the left temporal area was observed in the course of patient illness despite remission of the psychotic symptoms. Bilateral prefrontal metabolic under-activity was noted at the emergence of negative symptoms, executive neurocognitive dysfunction and the treatment-resistant state. After response to clozapine, the right prefrontal activity returned to a normal level. Our findings suggested that persistent left temporal underactivity detected by SPECT despite clinical remission may indicate a vulnerability for further relapses and development of a treatment-resistant state. Treatment-resistant state, negative symptoms and executive neurocognitive deficit may involve abnormal prefrontal metabolic activity and can be alleviated in clozapine-responsive patients.

[Cloning of cancer-related genes of Rat6 fibroblasts by using an improved differential display method]

The p53 gene is the most frequently mutated gene identified so far in human cancers. When a mutant p53(135)-val gene was allowed to be over-expressed in Rat6(R6) cells, a high incidence of spontaneous transformation was observed in long-term culture of this cell line(R6 # 13-8). To identify genes involved in cell transformation, parental p53 over-expressing cell, R6 # 13-8, and its spontaneous transformant T2, were analyzed by an improved mRNA differential display technique, which was reproducible, simpler, and was able to clone cDNA longer than 500 bp, and was with less false positives. When 33 10-mer or 12-mer single primers with arbitrary but defined sequence were used for PCR, over 90 discrete cDNAs were obtained from R6 # 13-8 and T2 cells. Three differentially expressed cDNAs were identified, one of them is highly expressed in T2 cells, while the other two, 0.8 kb and 0.9 kb long, are highly expressed in R6 # 13-8 cells. The latter were cloned and confirmed by Northern hybridization. Both cloned fragment were not homologous with any published sequence. Our results suggest that the activation and inactivation of genes are involved in the process of the spontaneous transformation from R6 # 13-8 to T2.

Clostridial gas gangrene. I. Cellular and molecular mechanisms of microvascular dysfunction induced by exotoxins of Clostridium perfringens

Mechanisms responsible for the rapid tissue destruction in gas gangrene are not well understood. To examine the early effects of Clostridium perfringens exotoxins on tissue perfusion, a rat model of muscle blood flow was developed. Intramuscular injection of a clostridial toxin preparation containing both phospholipase C (PLC) and theta-toxin caused a rapid (1-2 min) and irreversible decrease in blood flow that paralleled formation of activated platelet aggregates in venules and arterioles. Later (20-40 min), aggregates contained fibrin and leukocytes, and neutrophils accumulated along vascular walls. Flow cytometry confirmed that these clostridial toxins or recombinant PLC induced formation of P-selectin-positive platelet aggregates. Neutralization of PLC activity in the clostridial toxin preparation completely abrogated human platelet responses and reduced perfusion deficits. It is concluded that tissue destruction in gas gangrene is related to profound attenuation of blood flow initiated by activation of platelet responses by PLC.

Clostridial gas gangrene. II. Phospholipase C-induced activation of platelet gpIIbIIIa mediates vascular occlusion and myonecrosis in Clostridium perfringens gas gangrene

Clostridium perfringens gas gangrene is a fulminant infection, and radical amputation remains the single best treatment. It has been hypothesized that rapid tissue destruction is related to tissue hypoxia secondary to toxin-induced vascular obstruction, and previous studies demonstrated that phospholipase C (PLC) caused a rapid and irreversible decrease in skeletal muscle blood flow that paralleled the formation of intravascular aggregates of activated platelets, fibrin, and leukocytes. In this study, flow cytometry demonstrated that PLC stimulated platelet/neutrophil aggregation in a gpIIbIIIa-dependent fashion. Pretreatment of animals with heparin or depletion of leukocytes reduced blood-flow deficits, and aggregate formation caused by PLC. It is concluded that fulminant tissue destruction in gas gangrene results from profound attenuation of blood flow caused by PLC-induced, gpIIbIIIa-mediated formation of heterotypic platelet/polymorphonuclear leukocyte aggregates. Therapeutic strategies that target gpIIbIIIa may prevent vascular occlusion, maintain tissue viability, and provide an alternative to radical amputation for patients with this infection.

New annonaceous acetogenins from the roots of Uvaria calamistrata

Five new annonaceous acetogenins, calamistrins C-G (1-5), were isolated from an ethanolic extract of the roots of Uvaria calamistrata. Compounds 1-3 were mono-THF ring acetogenins; compounds 4 and 5 were bis-THF acetogenins, with the THF rings from C-18 to C-25. The absolute configurations of 3, 4, and 5 as well as the partial absolute configurations of 1 and 2 were determined by (13)C NMR spectroscopy and advanced Mosher methodology.

[Phylogenetic study of Artemia from China using RAPD and AFLP markers]

We have applied the techniques of RAPD (random amplified polymorphic DNA) and AFLP (amplified fragment length polymorphism) to the analysis of the relationships among Artemia species and strains. RAPD markers were successfully employed to detect diversity and genetic differentiation among four species of brine shrimp: A. franciscana, A. urmiana, A. sinica, and A. parthenogenetica. Seventy, ten-base synthetic oligonucleotides were used to amplify a total of 458 distinct fragments. DNA polymorphisms were found in all the species examined; The highest percentage of polymorphic bands found in A. parthenogenetica, was 28.8 per cent. There are significant differences between bisexual sibling species and parthenogenetic populations. A. parthenogenetica provided 94 specific molecular markers, while bisexual sibling species gave 27 specific molecular markers. A. sinica is a species distinct from the other Old World bisexual species. AFLP were used to analyze 15 Artemia species and strains for genetic diversity. They are extremely sensitive to even a small sequence variation and more polymorphism than RAPD. Using only 10 pairs of primer combinations, we detected 580 AFLP bands of which were polymerphic. The RAPD and AFLP techniques are powerful DNA fingerprinting methods for classification of Artemia species and strains.

Verbal fluency in schizophrenia: reduction in semantic store

OBJECTIVE

This is a study of the word production of patients with schizophrenia using a semantic verbal fluency task to address the unresolved issue of retrieval or storage impairment.

METHOD

Twenty-one patients with schizophrenia and 11 matched healthy subjects performed a semantic verbal fluency task on 'food', 'animal' and 'transport' categories in Cantonese for 3 minutes each on five separate trials.

RESULTS

Patients generated significantly fewer numbers of words compared with control on each trial. The estimated lexicon size of the patients was significantly smaller than that of the equivalent group. The amount of shared words and variable words generated in all five trials were reduced in the patient group.

CONCLUSIONS

Our results suggest that poor verbal fluency in patients with schizophrenia may partly be attributable to reduction in semantic store. The importance of temporal lobe involvement on verbal fluency deficits needs to be emphasised as an integral part of the neurobiological basis of schizophrenia research.

Isolation and structure elucidation of novel gamma-lactones from Saccopetalum prolificum

Two novel gamma-lactones, saccopetrin C(1) and saccopetrin D (2), were isolated from the roots of Saccopetalum prolificum. Their structures were established by spectroscopic and chemical methods.

A new bislabdane-type diterpenoid from the roots of cunninghamia lanceolata

Lanceolatic acid (1), a new bislabdane-type diterpenoid, has been isolated from the roots of Cunninghamia lanceolata. Its structure was elucidated on the basis of spectroscopic data interpretation and confirmed by single-crystal X-ray diffraction analysis.

Alkaloids from the roots of goniothalamus griffithii

Three new alkaloids-griffithazanone A (1), griffithdione (2), and griffithinam (3)-were isolated from the roots of Goniothalamus griffithii, along with six known compounds, 4-methyl-2,9, 10-(2H)-1-azaanthracenetrione (4), velutinam, aristololactam BI, aristololactam BII, aristololactam AII, and norcepharanone B. Their structures were elucidated on the basis of spectral and chemical methods. The absolute configuration of griffithazanone A (1) was determined by the preparation of Mosher's esters.