Factors associated with sexual dysfunction in men with HIV infection.

Where men have had access to successful treatment for HIV (highly active antiretroviral therapy), expectations of both patients and physicians alike have changed significantly over the past decade. Such men, living with HIV, expect to lead fully functional lives including a normal sex life. Sexual dysfunction is well described among men with HIV. We retrospectively analysed details of 190 consecutive men attending a dedicated sexual dysfunction service in our HIV unit over an 18-month period. We took note of the specifics of their HIV disease, illnesses other than HIV, as well as other risk factors associated with sexual dysfunction. Men with sexual dysfunction all commonly reported recreational drug use, hepatitis B and C co-infection, anxiety and depressive illnesses, peripheral neuropathy and lipodystrophy. There was a significant relationship between men complaining of retarded ejaculation and peripheral neuropathy. Sexual dysfunction in non-HIV settings is known to lead to poor adherence to prescribed medications, e.g. antihypertensive agents. Iatrogenic sexual dysfunction in patients may similarly have a potential to lead to poor antiretroviral compliance if not addressed.

Recommendations for the management of premature ejaculation: BASHH Special Interest Group for Sexual Dysfunction.

We present the British Association for Sexual Health and HIV (BASHH), Special Interest Group for Sexual Dysfunction updated recommendations for the management of premature ejaculation. The recommendations outline the physiology, prevalence, definitions, aetiological factors and patient assessment for this common sexual problem. Behavioural, local and systemic pharmacological treatments are discussed along with general recommendations and auditable outcomes.

The fluxes and transformations of suspended particles, carbon and nitrogen in the Humber estuarine system (UK) from 1994 to 1996: results from an integrated observation and modelling study.

Results from the first multi-constituent dynamic modelling study of the Humber estuarine system over seasonal time scales are presented. The model, constructed within the ECoS3 simulation software, has been calibrated using data obtained from 27 surveys of the Yorkshire Ouse and Humber estuaries during 1994-1996. The model is tidally averaged, and is one-dimensional in the vertical and in cross-section. Daily-varying longitudinal concentration profiles of SPM, POC, nitrate, nitrite and ammonium have been simulated, and these have been compared with the observations used for model calibration (model confirmation). The fits are generally good. The model captures the marked seasonal variability in concentrations of the particulate constituents (SPM, POC), and places the turbidity maximum in approximately the correct region of the estuary. There was a high degree of scatter in the SPM and POC concentrations measured due to tidal resuspension, which was not reproduced by the tidally averaged model. Comparisons between measured and simulated nitrate+nitrite are satisfactory, although for a number of surveys the modelled values are systematically too low in the lower Yorkshire Ouse and upper Humber. These discrepancies are not readily explained, but may be linked to inadequately characterised source terms for this nitrogen. The general trends in the concentrations and distributions of ammonium are reproduced by the model, despite the plethora of external inputs of this constituent, and significant modifications to ammonium transport by in situ nitrification and benthic exchange. The simulated concentrations and distributions have also been tested against independent data encapsulating axial transects in the Trent and Humber estuaries, and temporal variations at fixed sites on the Trent and Yorkshire Ouse estuaries. With some exceptions, the fits between the model results and these data are also good. The model has also been used to construct constituent budgets (external/internal sources and sinks) for each estuary for 1994, 1995 and 1996. Riverine inputs of SPM, POC, nitrate, nitrite and ammonium decreased over the 3 years, presumably reflecting changing patterns of terrestrial runoff coupled to a reduction in effluent inputs. This trend was also observed in the point discharges of these constituents direct to the estuary. The simulated estuary was a source of sediments to the North Sea during 1994 and 1996, but a sink during 1995. The difference has been ascribed to the exceptionally dry summer and autumn of 1995, in which up-estuary tidal 'pumping' of SPM was dominant over down-estuary flushing by river water. Fluvial inputs represent an important external source of POC to the model estuary (27-55%), as does the North Sea (26-58%). These inputs are exceeded by POC loss via bacterial remineralisation, suggesting that the estuarine bed is a net source of POC. Riverine inputs account for 76-77% of the external inputs of nitrate. This constituent behaves quasi-conservatively in the estuary, reflecting the dilution of nitrate-rich river waters with low-nitrate coastal water, although nitrification is a significant input (approx. 21%). Denitrification is small, and consequently all nitrate added to the estuary is lost to the North Sea. External loads of nitrite are small and ammonium nitrification accounts for approximately 93% of its annual input. Practically all of the nitrite is oxidised to nitrate, and little escapes to the North Sea. The fluvial and direct waste inputs of ammonium to the estuary are of similar size. Most of the ammonium in the model is nitrified (98-100%) and only a few tons are exported to the North Sea. In 1996 the estuary appears to have been a sink for coastal water ammonium. Constituent budgets are compared with independently evaluated fluxes. There is good agreement in a number of cases, but the comparison highlights the main uncertainties in the simulated fluxes. It is concluded that the model as currently formulated provides an excellent basis for heuristic studies of the Humber estuarine system.

Modelling solute transport in the Tweed Estuary, UK using ECoS.

Predictions of the tidal variation in water elevation and the advection-dispersion of solutes have been made for the Tweed River Estuary (UK) by application of a modelling package called ECoS. The estuarine model consisted of a one-dimensional hydrodynamic scheme with tidally variable channel cross-sectional area. The model was driven by predicted tidal elevation at the mouth of the estuary, and combined fluvial inputs observed for the River Tweed at the head of the estuary and the River Whiteadder, a tributary within the tidal reaches. Model results were compared to field data collected during routine surveys of the river estuary, conducted as part of Natural Environment Research Council Land-Ocean Interaction Study (LOIS). Validation protocols showed that the model reproduced tidal- and river flow-driven changes in surface elevation, and explained over 90% of the variation in salinity when field data were averaged through the water column. The study demonstrates that ECoS can be used to model tidal hydrodynamic processes, and that in a stratified estuary a depth-averaged model is able to replicate depth-averaged data. However, in rapidly rising and partially stratified estuaries with highly variable river flows, sufficient and appropriate data must be available for model set-up and validation. This has implications for how field studies should be planned and conducted.