Using geospatial methods to measure the risk of environmental persistence of avian influenza virus in South Carolina.

Avian influenza (AIV) is a highly contagious virus that can infect both wild birds and domestic poultry. This study aimed to define areas within the state of South Carolina (SC) at heightened risk for environmental persistence of AIV using geospatial methods. Environmental factors known to influence AIV survival were identified through the published literature and using a multi-criteria decision analysis with GIS was performed. Risk was defined using five categories following the World Organization for Animal Health Risk Assessment Guidelines. Less than 1% of 1km grid cells in SC showed a high risk of AIV persistence. Approximately 2% - 17% of counties with high or very high environmental risk also had medium to very high numbers of commercial poultry operations. Results can be used to improve surveillance activities and to inform biosecurity practices and emergency preparedness efforts.

Quantitative spectroscopic imaging with in situ measurements of tissue water T1, T2, and density.

The use of tissue water as a concentration standard in proton magnetic resonance spectroscopy ((1)H-MRS) of the brain requires that the water proton signal be adjusted for relaxation and partial volume effects. While single voxel (1)H-MRS studies have often included measurements of water proton T(1), T(2), and density based on additional (1)H-MRS acquisitions (e.g., at multiple echo or repetition times), this approach is not practical for (1)H-MRS imaging ((1)H-MRSI). In this report we demonstrate a method for using in situ measurements of water T(1), T(2), and density to calculate metabolite concentrations from (1)H-MRSI data. The relaxation and density data are coregistered with the (1)H-MRSI data and provide detailed information on the water signal appropriate to the individual subject and tissue region. We present data from both healthy subjects and a subject with brain lesions, underscoring the importance of water parameter measurements on a subject-by-subject and voxel-by-voxel basis.

A comparison between portable ultrasound (MIDUS) and nocturnal RigiScan when confirming the diagnosis of vascular organic erectile disorder.

In recent years, the use of RigiScan and ultrasound to assess erectile dysfunction has fallen from favour. However, in a small minority of specialist cases, where a vascular, neurogenic or psychogenic aetiology requires confirmation, there remains a need for further investigation. To establish if in a preliminary assessment the use of nocturnal RigiScan or male impotence diagnostic ultrasound system (MIDUS) represents best practice as a diagnostic investigation in patients with a history suggestive of vascular organic erectile disorder. Men attending both urological and psychosexual therapy clinics with erectile dysfunction were assessed using a generic assessment schedule. Patients with a history suggestive of vascular erectile disorder were offered the opportunity of dual investigation of their condition. After screening using a provocative RigiScan using visual stimuli that gleaned inconclusive results, patients were offered the chance to enter a study with both nocturnal RigiScan and MIDUS investigation. These were confined for the purposes of this study to RigiScan events, peak systolic flow velocity (PSV) and end-diastolic flow velocity (EDV) from ultrasound examination where an abnormal EDV is defined as in excess of 4.5 cm/s and a normal PSV is variously defined as being greater than 35 cm/s. In all, 38/43 (88%, 95% CI: 76-95%) of men had a nocturnal event exceeding 3 min on the RigiScan investigation. This compares with 17/43 (40%, 95% CI: 26-54%) of men with a normal EDV blood flow of less than 4.5 cm/s (P<0.017) and 32/43 (74%, CI: 60-85%) of men with a normal PSV flow greater than 35 cm/s (NS). Rigiscan and ultrasonography of the cavernosal vessels are of equal usefulness in suspected arterial penile disease although where veno-occlusive disease is suspected, ultrasonography is more specific.

Returning a referral for erectile dysfunction to the referrer by two different routes.

OBJECTIVE: To compare the prescribing pattern and attitude of general practitioners (GPs) in response to a clinic returning a patient referred for erectile dysfunction (ED) to the referrer by two different methods. METHODS: Referrals on a waiting list for an assessment of ED were reviewed and a subgroup of patients with criteria enabling them to be eligible for a prescription under the National Health Service (NHS) identified. The GP was informed either in writing or by telephone that the clinic had written to the patient, suggesting he make direct contact with his GP. A follow-up questionnaire was sent to each GP one month after the initial letter to the patient and contact with the GP. RESULTS: Of 91 questionnaires sent to GPs, 66 (73%) were completed; an additional five GPs corresponded by letter rather than completing the questionnaire. The long waiting time for assessment had led to 35% of patients having already tried sildenafil, and by the time the questionnaire was completed, 57% of patients had tried sildenafil. Ten times as many referrers indicated that they were happy to initiate a prescription for sildenafil than not to do so, for those men eligible for an NHS prescription. More GPs who had received a letter returned the completed questionnaire (80%) than those who had received a courtesy telephone call (64%). There were no differences between the groups of GPs in their attitude to our contact with their patient and no difference in prescribing pattern. Conclusion The provision of guidelines and advice to GPs either by telephone or letter is acceptable practice in reducing long waiting-list times for ED. Safe, simple and effective treatments are available for GPs to use under NHS guidelines.

Repetitive high G exposure is associated with increased occurrence of cardiac valvular regurgitation.

BACKGROUND: Exposure to repeated high +Gz loads and the methods to prevent loss of consciousness cause unique stresses on the cardiovascular system. The purpose of this study was to determine if the +Gz environment is associated with an increased occurrence of valvular regurgitation in pilots of high performance aircraft. METHODS: There were 247 subjects who were divided into pilot (n = 46) and non-pilot (n = 201) groups. Pilots were defined as those individuals who had flown at least 1000 h in high performance aircraft. The echocardiographic data of these subjects were examined retrospectively. RESULTS: We found a statistically significant association between pulmonic insufficiency and exposure to high +Gz stress in pilots vs. non-pilots (chi2 = 13.09, p = 0.0002). In addition, there was a greater incidence of tricuspid regurgitation (chi2 = 4.97, p = 0.025) and concurrent pulmonic insufficiency and tricuspid regurgitation (chi2 = 14.1, p = 0.0002) in the pilot group. CONCLUSIONS: There is a direct relationship between repetitive exposure to a +Gz environment and pulmonic insufficiency, tricuspid regurgitation, or concurrent pulmonic insufficiency and tricuspid regurgitation. This may be secondary to the transient increase in right ventricular pressure due to acceleration forces or straining maneuvers utilized to prevent or postpone +Gz induced loss of consciousness (G-LOC).

Induction of receptive field plasticity in the auditory cortex of the guinea pig during instrumental avoidance conditioning.

Classical tone conditioning shifts frequency tuning in the auditory cortex to favor processing of the conditioned stimulus (CS) frequency versus other frequencies. This receptive field (RF) plasticity is associative, highly specific, rapidly acquired, and indefinitely retained-all important characteristics of memory. The investigators determined whether RF plasticity also develops during instrumental learning. RFs were obtained before and up to 24 hr after 1 session of successful 1-tone avoidance conditioning in guinea pigs. Long-term RF plasticity developed in all subjects (N = 6). Two-tone discrimination training also produced RF plasticity, like classical conditioning. Because avoidance responses prevent full elicitation of fear by the CS, long-term RF plasticity does not require the continual evocation of fear, suggesting that neural substrates of fear expression are not essential to RF plasticity.

A comparison of tone-evoked response properties of 'cluster' recordings and their constituent single cells in the auditory cortex.

This study examined relationships between some acoustic response properties of 'cluster' recordings (CL) and their constituent single cells (SU) in the auditory cortex obtained from 22 clusters comprised of 63 responsive single units mainly in the anterior tonotopic field of the waking guinea pig. Response parameters included characteristic frequency (CF), threshold (Th) at CF, bandwidth 10 (BW10) and 30 (BW30) dB above Th. Clusters and single units were classified by their pattern of discharges as either 'onset' or 'sustained' response types. Comparison of CL and their constituent SU revealed differences in one or more response parameters in all CL. The CFs of onset CL were generally the same as the CFs of their constituent onset SU in contrast to sustained CL for which greater differences were observed in CF. The Th of all CL differed from that of some of their cells. The BW of approximately 50% of CL differed from their SU. The findings indicate that cluster recordings are often not good predictors of the response parameters of all of their constituent neurons.

Effects of dopamine D1 and D2 receptor antagonists on oral activity in rats.

Two experiments were performed to investigate the actions of the selective D1 blocker SCH 23390 and the selective D2 blocker sulpiride, on oral movements in rats; these were quantified by a human observer scoring vacuous chewing movements (VCMs), jaw tremor and head movements, as well as a computer analysis system which measured the amplitude and slope of each movement. In the first experiment it was found that both SCH 23390 and sulpiride decreased VCMs and head movements in a dose-dependent manner, with SCH 23390 more effectively decreasing head movements and sulpiride more effectively decreasing VCMs. In a second experiment, the effectiveness of these two drugs in blocking the actions of selective D1 (SKF 38393) and D2 (LY 171555) agonists was studied. The SKF 38393-induced increase in computer-scored movement was attenuated by both sulpiride and SCH 23390, whereas the LY 171555-induced decrease in VCMs was attenuated by sulpiride, while SCH 23390 exacerbated it. These findings, together with our earlier results, suggest a simple relationship of D1 receptors to oral movement, with increased activation resulting in increased oral movement and decreased activation resulting in decreased oral movement. The relationship of D2 receptors to oral movement shows a more complex pattern, with both stimulation and blockade decreasing oral movement. One possibility may be the existence of more than one subpopulation of D2 receptors mediating these effects.