Hyperthyroidism and thyroid cancer risk: a population-based cohort study.

AIM: Thyroid hormones regulate the rate of metabolism and affect the differentiation and growth of many tissues in the body. We investigated the association between hyperthyroidism and cancer risk in Taiwan. PATIENTS AND METHODS: A random sample of 1 000 000 individuals from Taiwan's National Health Insurance database was enrolled. We found 17 033 patients to have newly diagnosed hyperthyroidism between 2000 and 2005. These patients were recruited along with a match cohort of 34 066 patients without hyperthyroidism. Starting from index date, we followed up all patients for 4 years to identify those who developed cancer. RESULTS: During the 4-year follow-up study, cancer was diagnosed in 1.23% of patients with hyperthyroidism and 1.02% of the member of the comparison cohort. Regression analysis showed that patients with hyperthyroidism were at greater risk of cancer incidence, especially thyroid cancer, compared the comparison cohort (HR: 1.213; 95% CI: 1.022-1.440; p<0.05 and HR: 7.355; 95% CI: 3.885-13.92; p<0.05, respectively). After adjusting for age, gender, diabetes mellitus, hypertension, hyperlipidemia, gout, geographic region, and income, patients with hyperthyroidism remained at increased risk of cancer incidence and thyroid cancer (Adjusted HR: 1.206; 95% CI: 1.015-1.433 and 6.803; 95% CI: 3.584-12.91, respectively) (both p<0.05). The longer the duration of hyperthyroidism, the greater the risk of thyroid cancer. CONCLUSIONS: This 4-year follow up study suggests that patients with hyperthyroidism are at increased risk of cancer, especially thyroid cancer.

Association study of polymorphisms in glycine transporter with schizophrenia.

Glycine acts as an obligatory co-agonist with glutamate on N-methyl-D-aspartate (NMDA) receptors. Brain glycine availability is determined by glycine transporters (GlyT1 or SLC6A9), which mediate glycine reuptake into nerve terminals. Since hypofunction of NMDA receptors has been implicated in the pathophysiology of schizophrenia, this study tests the hypothesis that GlyT1 genetic variants confer susceptibility to schizophrenia. Four GlyT1 polymorphisms were studied in a sample population of 249 people with schizophrenia and 210 normal controls. One polymorphism (rs16831541) was not informative in our Chinese population while the other three polymorphisms (rs1766967, rs2248632 and rs2248253) were analysed with chi-square tests and haplotype analysis. Significant linkage disequilibrium was obtained among the three polymorphisms. Neither single marker nor haplotype analysis revealed an association between variants at the GlyT1 locus and schizophrenia, suggesting that it is unlikely that the GlyT1 polymorphisms investigated play a substantial role in conferring susceptibility to schizophrenia in the Chinese population. Further studies with other GlyT1 variants, relating either to schizophrenia, psychotic symptoms or to therapeutic response in schizophrenia, are suggested.

A sleep laboratory evaluation of an automatic positive airway pressure system for treatment of obstructive sleep apnea.

STUDY OBJECTIVES: This paper compares the performance of an experimental nasal positive airway pressure device that automatically adjusts the level of applied pressure (APAP) with the performance of a conventional continuous positive airway pressure (CPAP) in a sleep laboratory study. DESIGN: In a randomized sequence, conventional CPAP therapy was applied for 1 night (CPAP night) and APAP therapy the following night (APAP night). SETTING: The study was conducted in an accredited sleep disorders center. PATIENTS OR PARTICIPANTS: Twenty-six men and 5 women between the ages of 35 to 73 (51 +/- 9.6) years with body mass index 35.82 +/- 8.35 (kg/m2) who were diagnosed (using standard nocturnal polysomnography [NPSG] methods) as having OSA syndrome were studied. The subjects were treated with conventional CPAP for approximately 8 (7.79 +/- 3.16) weeks at home prior to their participation in this study. MEASUREMENTS AND RESULTS: All standard polysomnography data and nasal mask pressures were recorded using a computer-based data acquisition system. Sleep and respiratory data were scored by a registered polysomnographer. The mean apnea-hypopnea index (AHI) for subjects for the NPSG night was 55.2 +/- 33.7. It dropped to 4.2 +/- 3.8 for the CPAP night and to 5.4 +/- 5.4 for the APAP night. There was no significant (p = 0.05) difference between mean AHI indices, sleep stages, sleep stage shifts, and snore arousals for CPAP night and APAP night. However, all the measures showed significant (p = 0.05) improvement over NPSG night. The mean of APAP applied pressure (8.4 +/- 3.3 cm H2O) was significantly (p = 0.05) lower than the prescribed pressure (11.5 +/- 3.1 cm H2O), but there was no significant (p = 0.05) difference between the maximum APAP applied pressure (12.8 +/- 4.3 cm H2O) and the prescribed pressure (11.5 +/- 3.1 cm H2O). All mean comparison tests were carried out using two-tailed statistics. CONCLUSIONS: APAP appears to be as effective as CPAP in treating OSA patients. APAP delivers the same level of therapy as CPAP, but it reduces the average airway pressure while providing needed peak pressures.

A noninvasive technique for detecting obstructive and central sleep apnea.

A new noninvasive method to detect obstructive and central sleep apnea [(OSA) and (CSA)] events is described. Data were collected from ten volunteer subjects with a previous diagnosis of OSA while they were titrated for continuous positive airway pressure (CPAP) therapy. Apneic events were identify by analyzing of estimated airway impedance determined from pressure and airflow signals delivered from CPAP. To enhance performance of this technique, a single-frequency (5 Hz with 0.5 cmH2O peak-to-peak amplitude) probing signal was superimposed on the applied CPAP pressure. The results indicated that estimated airway impedance during OSA (mean: 17.9, SD: 3.4, N = 50) was significantly higher then during CSA (mean: 4.1, SD: 1.7, N = 50). When the estimated impedance of OSA and CSA events were compared to a fixed threshold, 100% of all events can be correctly categorized. These results indicate that it may be possible to diagnose OSA and CSA noninvasively based upon this technique. The instrument and the algorithm required are relatively simple and can be incorporated in a home-based device. If this method was used for prescreening apnea patients, it could reduce cost, waiting time, and discomfort associated with traditional diagnostic procedures.

Pharyngeal wall vibration detection using an artificial neural network.

An artificial-neural-network-based detector of pharyngeal wall vibration (PWV) is presented. PWV signals the imminent occurrence of obstructive sleep apnoea (OSA) in adults who suffer from OSA syndrome. Automated detection of PWV is very important in enhancing continuous positive airway pressure (CPAP) therapy by allowing automatic adjustment of the applied airway pressure by a procedure called automatic positive airway pressure (APAP) therapy. A network with 15 inputs, one output, and two hidden layers, each with two Adaline-nodes, is used as part of a PWV detection scheme. The network is initially trained using nasal mask pressure data from five positively diagnosed OSA patients. The performance of the ANN-based detector is evaluated using data from five different OSA patients. The results show that on the average it correctly detects the presence of PWV events at a rate of approximately 92% and correctly distinguishes normal breaths approximately 98% of the time. Further, the ANN-based detector accuracy is not affected by the pressure level required for therapy.

Automatic control of airway pressure for treatment of obstructive sleep apnea.

Obstructive sleep apnea (OSA) occurs when airflow ceases because of pharyngeal wall collapse in sleep. Repeated apneic events results in the development of a pathological condition called OSA syndrome. We describe the methodology and design of a prosthetic device, named automatic positive airway pressure (APAP), for treatment of this syndrome. APAP applies a stream of air via a nasal mask at an initial pressure selected by the patient. By sensing specific pressure characteristics of air flow immediately preceding pharyngeal wall collapse, the APAP device automatically raises the applied pressure to maintain a patent upper airway and thus prevent apnea. Conversely, when such conditions are absent, pressure is lowered step wise until a preselected minimum pressure is reached. Performance evaluation of the APAP system in five OSA patients and five normal (asymptomatic for sleep apnea) subjects revealed that it effectively treated OSA syndrome. It lowered the apnea-hypopnea index without disturbing sleep and resulted in a lower mean airway pressure compared to the traditional continuous positive airway pressure (CPAP) therapy. The results also show that the pressure needed to prevent OSA varied significantly throughout the night. For OSA syndrome patients, this pressure ranged from 3 to 18 cm H2O. The mean airway pressure for these patients had a sample average of 6.80 cm H2O and a standard deviation of 3.17 cm H2O. In normal subjects, the device did not raise pressure except in response to Pharyngeal Wall Vibration events.

Sex pheromone components from asian corn borer,Ostrinia furnacalis (Hubner) (Lepidoptera: Pyralidae) in Taiwan.

The female sex pheromone of the Asian com borer,Ostrinia furnacalis, widespread in Taiwan, was confirmed as (Z)-12-tetradecenyl acetate and its geometric isomer (E)-12-tetradecenyl acetate in a ratio of ca. 3∶1 by gas chromatography and gas chromatography-mass spectrometry in selected ion monitoring mode. Males were attracted by the mixture of these two synthetic components in the field, but the attractiveness was less than by virgin females. The presence of minor components in the sex pheromone was therefore suggested.