Prevalence and risk behaviors of Chinese men who seek same-sex partners via the internet in Hong Kong.

To examine the prevalence of Internet sex networking among men who have sex with men (MSM) in Hong Kong and risk behaviors associated with the behavior, a telephone survey of 15,230 Hong Kong Chinese men aged 18-60 was conducted. Of the 283 active MSM (having engaged in some MSM behaviors in the last 6 months) identified, 17.7% had networked for MSM partners via the Internet in the last 6 months. Younger age (odds ratio [OR] for age < or = 25 vs. age >25 = 4.67, 95% confidence interval [CI] = 2.35-9.28) and being an anal-sex MSM (OR = 4.72, 95% CI=2.36-9.44) were independent predictors of Internet sex networking. Being an Internet sex networker was associated with some risk behaviors such as having contracted a sexually transmitted disease (adjusted OR = 4.79, 95% CI = 1.34-17.11), having had > or = 3 MSM partners (adjusted OR = 4.74, 95% CI = 2.20-10.23), and having engaged in anal sex (adjusted OR = 3.95, 95% CI = 1.89-8.23). HIV prevention programs for MSM should thereby include Internet-based interventions.     

Comparison of 180° and 360° acquisition for myocardial perfusion SPECT with compensation for attenuation, detector response, and scatter: Monte Carlo and mathematical observer results

BACKGROUND: The optimal projection data acquisition strategy for myocardial perfusion (MP) single photon emission computed tomography (SPECT) remains controversial. METHODS: We compared MP SPECT using 180 degrees and 360 degrees projection data obtained with the same acquisition time, reconstructed either with filtered back projection (FBP) or the iterative ordered-subsets expectation maximization (OS-EM) algorithm with various combinations of attenuation, detector response, and scatter compensation using mathematical observers and a myocardial defect detection task. We used Monte Carlo-simulated projection data from a population of 3-dimensional nurbs-based cardiac-torso (NCAT) phantoms with ranges of variability in patient anatomy, organ uptake, defect location, defect size, and noise level based on clinical data. Projection data from 180 degrees and 360 degrees acquisitions were generated by assuming the same acquisition time. After iterative or FBP reconstruction, standard postprocessing methods were applied. For each acquisition and reconstruction method, we optimized the number of iterations and cut-off frequency of the Butterworth filter using the Channelized Hotelling Observer methodology. The optimum set of parameters was that which gave the maximum area under the curve. RESULTS: For both acquisition protocols, OS-EM with compensations provided better performance than FBP or OS-EM without compensation. For FBP, the optimized 180 degrees acquisition provided a statistically significant increase in AUC as compared with optimized 360 degrees acquisition. For OS-EM, the AUCs for 180 degrees were slightly larger than for 360 degrees acquisitions when comparing images reconstructed with the same compensations. However, the differences were smaller and not statistically significant. CONCLUSION: With optimized reconstruction and filtering parameters, 180 degrees acquisition provided a statistically significant improvement over 360 degrees acquisition for FBP reconstruction. However, for OS-EM the differences were small and not statistically significant.     

Peak velocities of visually and nonvisually guided saccades in smooth-pursuit and saccadic tasks

 Smooth pursuit typically includes corrective catch-up saccades, but may also include such intrusive saccades away from the target as anticipatory or large overshooting saccades. We sought to differentiate catch-up from anticipatory and overshooting saccades by their peak velocities, to see whether the higher velocities of visually rather than nonvisually guided saccades in saccadic tasks may be found also in saccades in pursuit. In experiment 1, 12 subjects showed catch-up, anticipatory, and overshooting saccades to comprise 70.4% of all saccades in pursuit of periodic, 30°/s constant-velocity targets. Catch-up saccades were faster than the others. Saccadic tasks were run as well, on 19 subjects, including the 12 whose pursuit data were analyzed, with target-onset, target-remaining (saccade to the remaining target when the other three extinguish), and antisaccade tasks. For 17 of the 19 subjects, antisaccade velocities were lower than for either target-onset or target-remaining tasks. Velocities for the target-remaining task were near those for target onset, indicating that target presence, not its onset, defines visually guided saccades. Error and reaction-time data suggest greater cognitive difficulty for target remaining than for target onset, so that the cognitive difficulty of typical nonvisually guided saccade tasks is not sufficient to produce their lowered velocity. To produce reliably, in each subject, catch-up and anticipatory saccades with comparable amplitude distributions, nine new subjects were asked in experiment 2 to make intentional catch-up and anticipatory saccades in pursuit, and were presented with embedded target jumps to elicit catch-up saccades, all with periodic target trajectories of 15°/s and 30°/s. Velocities of intentional anticipatory saccades were lower than velocities of intentional catch-up saccades, while velocities of intentional and embedded catch-up saccades were similar. Target-onset and remembered-target saccadic tasks were run, showing the expected higher velocity for the target-onset task in each subject. Both experiments demonstrate higher peak velocities for catch-up saccades than for anticipatory saccades, suggesting that cortical structures preferentially involved in nonvisually guided saccades may initiate the anticipatory and overshooting saccades in pursuit. Received: 1 December 1995 / Accepted: 25 February 1997     

Attitudes towards mental illness: testing the contact hypothesis among Chinese student nurses in Hong Kong

This study investigated whether previous contact with mental illness affected the attitudes to mental illness (AMI) of general student nurses in Hong Kong — the contact hypothesis. We employed a quasi-experimental design. We compared the attitudes to mental illness of students who had previous contact with mental illness through having taken a psychiatric secondment with those who had not taken a psychiatric secondment. Also, we compared the AMI of: students who had taken other courses related to mental illness with those who had not; those who had a family history of mental illness with those who had not; and those who lived with a mentally ill relative with those who did not. We found that previous contact with mental illness had no significant effect on the attitudes to mental illness of the students. In other words our findings do not support the contact hypothesis. Our sample expressed positive general attitudes to mental illness when presented with general issues about mental illness. However, their attitudes were less positive when presented with specific issues about mental illness that might impinge upon their daily lives. We discuss the implications of these findings for mental health nursing practice, education and research.     

An audit of the safety of an acute pain service

We audited and analysed the adverse effects and safety of postoperative pain management on 2509 consecutive patients under care of the Acute Pain Service at a tertiary referral teaching hospital over a 32-month period. Our standard respiratory monitoring consisted of continuous pulse oximetry, hourly respiratory rate counting, sedation scoring and intermittent arterial blood gas sampling. This protocol was reliable and detected six episodes of bradypnoea, 13 of hypercapnia and 23 of oxygen desaturation occurring in 39 patients (1.8% of all spontaneously breathing patients) . Two patients required naloxone injection and none had long-term sequelae. Hypotension due to epidural bupivacaine 0.0625% and fentanyl 3.3 μg.ml⁻¹ infusion occurred in four patients (1.2%), all with a sensory block higher than T₅. They readily responded to fluid infusion and ephedrine (two patients). Postoperative nausea or vomiting occurred in 723 (28.8%) and 380 (15.1%) patients, respectively. Odds ratio analysis showed that the risk factors for postoperative nausea and vomiting were: female gender, gynaecological operations, nongeriatric patients and systemic analgesia. Postoperative nausea and vomiting decreased analgesic efficacy by discouraging the use of patient-controlled analgesia and was regarded as equally distressing as pain. Other side-effects included: pruritus in 182 patients; dizziness in 333 and lower limb weakness in 73 (21.2% of patients receiving epidural local anaesthetics). It is concluded that a standard monitoring and management protocol, an experienced nursing team and reliable Acute Pain Service coverage is mandatory for the safe use of modern analgesic techniques.     

Rebound intracranial hypertension after treatment of spontaneous intracranial hypotension

Spontaneous intracranial hypotension (SIH) is characterized by orthostatic headache and the cause is usually cerebrospinal fluid leaks in spine level. Most patients with SIH have a benign course. Epidural blood patch (EBP) is the treatment of choice when initial conservative managements are ineffective. We reported a patient with SIH diagnosed by using magnetic resonance imaging and radionuclide cisternography. Acute rebound intracranial hypertension developed after EBP and was successfully treated with intravenous osmotic agent.     

Simultaneous acquisition of emission and transmission data for improved thallium-201 cardiac SPECT imaging using a technetium-99m transmission source.

Transmission computed tomography (TCT) data provides useful complementary information to single-photon emission computed tomography (SPECT) reconstructions, especially for cardiac studies. In particular, TCT data has been used to correct for nonuniform attenuation in the chest. Typically the transmission data are acquired in a separate acquisition, but simultaneous acquisition is preferable both to save time and to avoid difficulties involved with registration. In this work, we present a technique for simultaneously acquiring 201Tl SPECT and TCT data using a 99mTc sheet source that requires only minor equipment modifications. The use of these isotopes results in cross-contamination of the emission and transmission data. We present a practical technique to compensate for this contamination using post-acquisition image processing. This technique was evaluated by performing phantom and patient studies. The resulting images compare well with data obtained from separate emission and transmission studies.     

Cerebral glucose metabolism in Parkinson's disease with and without dementia.

Although cognitive impairment is commonly associated with Parkinson's disease, the relative importance of cortical and subcortical pathologic changes to the development of dementia is controversial. Characteristic abnormalities in cortical glucose metabolism have been reported previously in Alzheimer's disease, a disease in which cortical changes predominate. We measured cerebral glucose metabolism with positron emission tomography in 20 control subjects and in 14 patients with PD with mental status ranging from normal to severely demented to determine whether changes in cortical glucose metabolism occur in early PD and whether the degree and pattern of metabolic change relate to the severity of dementia. The patients were divided into demented and nondemented groups according to the results of neuropsychological assessment. Age-adjusted covariance analyses were performed, since the age distribution varied between groups. The nondemented patients with PD showed widespread cortical glucose hypometabolism without any selective temporoparietal defects. The pattern of glucose hypometabolism seen in the demented patients with PD resembled that described in patients with Alzheimer's disease; ie, there was a global decrease in glucose metabolism, with more severe abnormalities observed in the temporoparietal regions.     

Validating the self-reported fertility status of rural Malawian women.

This study uses data from a population-based survey to examine the fertility schedules of 704 women in a rural district of Malawi. The main objective is to assess self-reported fecundity status as a measure of fertility impairment. Life tables are used to examine the timing and tempo of births for women reporting difficulty getting pregnant as compared to women with no reported fecundity difficulties. Results of the analysis indicate that women with self-reported fecundity difficulties are older at each birth and have longer median birth intervals than do women with no reported difficulties. Cox proportional hazards models show that the report of a difficulty getting pregnant is significantly associated with at least a 30% lower likelihood of a first, second, or third birth. The relationships are not modified when accounting for demographic characteristics, previous sexual behaviors, or STI status.