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Biomedical subjects

D S Baldwin

Publications and source records attributed to D S Baldwin.

At least 19 recordsLinked to original sources
PubMed2006

Distribution of inland wetlands with sulfidic sediments in the Murray-Darling Basin, Australia.

This project examined the extent of sulfidic sediments in freshwater wetlands of the Murray-Darling Basin, Australia. We sampled 81 wetlands throughout the basin with methods previously developed for the analysis of coastal acid sulfate soils. Sulfidic sediments are generally regarded as a coastal phenomenon. We tested the hypothesis that elevated concentrations of mineral sulfides may also accumulate in sediments of inland wetlands. Of the 81 wetlands sampled, 17 (21%) contained reduced sulfur in sediments at concentrations above suggested trigger values. Most of the affected wetlands were adjacent to the Murray River, with only several associated with other major river catchments. Reduced sulfur in the sediments was positively correlated with sulfate concentrations in the overlying water column. This represents a concern for wetland managers because of the increasing desire to return wetlands to a more natural wetting and drying cycle to improve wetland health. However, during drying, sulfidic sediments oxidise and produce acid, which may exceed the buffering capacity of the system and ultimately harm aquatic life. Therefore, if sulfidic sediments are present, a drying phase should only be reinstated after careful consideration of the potential acidification risks. This study verified that sulfidic sediments can occur in freshwater wetlands in concentrations that could pose an ecological risk if mismanaged.

Australia↗
PubMed2003

Temporal variability of dissolved P speciation in a eutrophic reservoir--implications for predicating algal growth.

Weak-anion exchange chromatography was used to explore the temporal variability in the speciation of dissolved P in the surface layer of a eutrophic reservoir. Authentic free ortho-P ion was the most common form of P on three of the five sampling occasions-including during a bloom of the green algae Botryococcus braunii indicating that the bloom was not P limited. Conversely, the absence of authentic ortho-P during a bloom of the dinoflagellate Ceratium hirundinella suggested the bloom was either P limited or co-limited. These observations were confirmed by algal-growth bioassay experiments.

Chlorophyta↗
PubMed2003

A simple, reproducible substrate for studying biofilms in aquatic environments.

In this paper we present a simple in expensive substrate for studying biofilms. Bioballs are robust plastic spheres with high surface area to volume ratios (ca 130:1) used in home aquarium filters. Their properties make them ideal substrates for use in studies of aquatic biofilms. As examples, in this paper we describe the growth and enzyme activities of biofilms grown on these substrates and explore the interaction between DOC concentration and biofilm biomass. Biofilm growth and activity on the bioballs was very reproducible. For example maximum biofilm growth following approximately 3 months inundation was estimated to be 40 (+/- 3.6) mg protein and 120 (+/- 11) microg chlorophyll a per bioball.

Biofilms↗
PubMed2002

Antidepressant medications: a review of the evidence for drug-induced sexual dysfunction.

BACKGROUND: Sexual dysfunction is recognised as a potential side effect of antidepressant therapy. However, there is little detailed information on the prevalence of drug-induced sexual dysfunction or the differences, if any, between available drugs. This article is a critical review of the literature in the area. METHODS: English-language studies on sexual dysfunction and depression or antidepressant treatments were identified by searching Medline and supplemented by manual review of their reference lists and recent journal issues available in a library. Trials of antidepressant use in anxiety disorders were identified from a Medline search and their adverse events tables scanned for data on sexual dysfunction. All trials were assessed according to predefined criteria. RESULTS: Sexual dysfunction is widespread in the healthy non-depressed population and is a recognised symptom of depression and/or anxiety disorders. Sexual dysfunction has been reported with all classes of antidepressants (MAOIs, TCAs, SSRIs, SNRIs and newer antidepressants) in patients with depression and various anxiety disorders. Numerous studies have been published, but only one used a validated sexual function rating scale and most lacked either a baseline or a placebo control or both. None met all of the pre-defined assessment criteria. LIMITATIONS: The search techniques may have missed some studies and publication bias cannot be ruled out. CONCLUSIONS: The existing literature confirms sexual dysfunction as a possible adverse event of all antidepressants, but it is not sufficiently robust to support claims for differences in the incidence of drug-induced sexual dysfunctions between existing antidepressant therapies. Prescribing decisions should be based on a careful assessment of the benefits and risks of therapy in the individual patient.

Adult↗
PubMed2002

Elderly suicide rates in Asian and English-speaking countries.

OBJECTIVE: Asian culture venerates elderly people. It was hypothesized that elderly suicides would be proportionately lower in Asian societies than in English-speaking countries (ESC). METHOD: Elderly (i.e. aged 75 years or more) to general population suicide ratios were compared for six Asian societies and six ESC, based upon the latest 5-year suicide rates. RESULTS: Males: The general population suicide rate was highest in rural China (227 per million) and third highest in Japan (217 per million), but other countries with high rates were all ESC (ranging from 224 to 198 per million). Asian countries had the six highest elderly suicide rates, 1327-1373 per million, whilst the highest ESC elderly rate was in the United States (507 per million). Asian societies had the widest range of elderly/general ratios, ranging from 6.62 to 2.6. Females: The overall suicide rates were higher in Asian countries (57-95 per million) than in ESC (40-56 per million). Asian elderly suicide rates differed (932 per million in rural China to 154 per million in Korea) but the highest ESC rate was in Australia (76 per million). The Asian countries elderly/general ratios ranged from 5.82 : 1 to 2.70 : 1, but the widest ESC ratio was 1.71 : 1, in the United Kingdom. CONCLUSION: There is a need for country-specific prevention measures in elderly people, and particularly for older women in Asian countries.

Adolescent↗
PubMed2002

Optimizing outcomes in depression: focus on antidepressant compliance.

Major depressive disorder is a chronic and recurrent illness that is associated with significant morbidity and mortality. Patients frequently experience recurrent depressive episodes that are of longer duration and increased severity and which are less responsive to treatment than the index episode. Despite the highly prevalent nature of the illness, depression is frequently unrecognized and undertreated. Compliance with antidepressant medication is essential to consolidate treatment response and prevent relapse and recurrence. However, compliance with antidepressant medication is poor. Education of the patient and physician regarding the nature of depression and its treatment is essential for improving patient compliance. Although psychological mechanisms are a major factor affecting patient compliance, speed of onset of action and poor tolerability of antidepressant medication also have a considerable influence on patient compliance. The newer antidepressants, such as selective serotonin reuptake inhibitors, nonselective serotonin-norepinephrine reuptake inhibitors, and the selective norepinephrine reuptake inhibitors, are better tolerated than tricyclic antidepressants, possibly resulting in improved compliance and treatment outcome.

Antidepressive Agents↗
PubMed2001

Hydrolysis of an organophosphate ester by manganese dioxide.

Amorphous manganese dioxide facilitates the hydrolysis of p-nitrophenyl phosphate to p-nitrophenol and orthophosphate despite insignificant adsorption of p-nitrophenyl phosphate or p-nitrophenol to the manganese dioxide. At pH 8, the orthophosphate product is released into solution; at pH 4 and pH 6, some remains adsorbed. The rate of hydrolysis is an order of magnitude more rapid than the same reaction facilitated by iron oxides. Because manganese dioxides are ubiquitous components of soils and sediments, this suggests the possibility of significant abiotic pathways for the formation of bioavailable orthophosphate from phosphate ester precursors.

Biological Availability↗
PubMed2001

Abiotic hydrolysis of the detergent builder tripolyphosphate by hydrous manganese dioxide.

The hydrolysis of tripolyphosphate to orthophosphate is facilitated by suspensions of amorphous manganese dioxide. Pyrophosphate is observed as an intermediate. The rate enhancement decreases with increasing pH. The weak sorption of orthophosphate on the oxide also decreases with increasing pH, indicating that the orthophosphate product would be bioavailable. The presence of calcium ions in natural waters increases both the rate of hydrolysis of tripolyphosphate and the extent of sorption of orthophosphate. Under some circumstances this abiotic mechanism could play a significant role in the hydrolysis of tripolyphosphate in the aquatic environment.

Detergents↗
PubMed2001

Depression and sexual dysfunction.

Adequate sexual expression is an essential part of many human relationships, and may enhance quality of life and provide a sense of physical, psychological and social well-being. Epidemiological and clinical studies show that depression is associated with impairments of sexual function and satisfaction, even in untreated patients. Most antidepressant drugs have adverse effects on sexual function, but accurate identification of the incidence of treatment-emergent dysfunction has proved troublesome, as disturbances of the sexual response can only be detected in a reliable fashion when systematic enquiries are made before and during the course of treatment. Growing awareness of the adverse effects of many antidepressants on sexual function has led to attempts to resolve dysfunction though adjuvant or substitution treatment approaches. There is a need for further studies of the effects of antidepressants on sexual function.

Antidepressive Agents↗
PubMed2001

A randomized, double-blind controlled comparison of nefazodone and paroxetine in the treatment of depression: safety, tolerability and efficacy in continuation phase treatment.

We investigated the safety, tolerability and efficacy of nefazodone and paroxetine in the continuation phase of treatment of depression. The study comprised a double-blind, parallel-group comparison over 4 months, of patients who had previously improved following random allocation to nefazodone or paroxetine during an 8-week acute treatment study. Assessments included Clinical Global Impression Scales, Hamilton Rating Scales for Depression and Anxiety, Montgomery-Asberg Depression Rating Scale and the Patient Global Assessment Scale, in addition to a review of reported adverse events, vital sign measurements, electrocardiograms and clinical laboratory tests. One hundred and eight patients participated in the continuation study (53 received paroxetine, 55 nefazodone) and 73 completed treatment. No clinically relevant differences in antidepressant efficacy were seen. Headache and somnolence were the most common reported adverse events in both treatment groups. Both nefazodone and paroxetine maintain their efficacy in continuation treatment, and both are generally well tolerated.

Adult↗
PubMed2001

The Wessex Recent In-Patient Suicide Study, 1. Case-control study of 234 recently discharged psychiatric patient suicides.

BACKGROUND: Psychiatric patients have a higher suicide risk following hospital discharge. AIMS: To identify social, clinical and health-care delivery factors in recently discharged patients. METHOD: Retrospective case-control study of 234 patients who died within 1 year of hospital discharge, matched for age, gender, diagnosis and admission period with 431 controls. Odds ratios for identified risk factors were calculated using conditional multiple logistic regression. RESULTS: Independent increased-risk factors were: not being White; living alone; history of deliberate self-harm (DSH); suicidal ideation precipitating admission; hopelessness; admission under different consultant; onset of relationship difficulties; loss of job; in-patient DSH; unplanned discharge; significant care professional leaving/on leave. Reduced-risk factors were: shared accommodation; delusions at admission; misuse of non-prescribed substances; and continuity of contact. CONCLUSIONS: Continuity of contact may reduce suicide risk. Discontinuity of care from a significant professional is associated with increased risk of suicide.

Adolescent↗
PubMed2001

The Wessex Recent In-Patient Suicide Study, 2. Case-control study of 59 in-patient suicides.

BACKGROUND: Psychiatric patients have an elevated risk of suicide while in hospital. AIMS: To compare social, clinical and health-care delivery factors in in-patient and out-patient suicides and their controls. METHOD: Retrospective case-control study of 59 in-patients and 106 controls, matched for age, gender, diagnosis and admission date. Odds ratios were calculated using conditional multiple logistic regression. RESULTS: There were seven independent increased-risk factors: history of deliberate self-harm, admission under the Mental Health Act, involvement of the police in admission, depressive symptoms, violence towards property, going absent without leave and a significant care professional being on leave. When compared with out-patient suicides, in-patients were more often female and male in-patients had a psychotic illness. Unlike the out-patient suicides, social factors were not found to be significant. CONCLUSIONS: The characteristics of in-patient and out-patient suicides differ. Identified risk factors have relatively low sensitivity and specificity.

Case-Control Studies↗
PubMed2000

Clinical experience with paroxetine in social anxiety disorder.

Paroxetine is a selective serotonin reuptake inhibitor (SSRI) with proven efficacy in the treatment of depression, panic disorder and obsessive-compulsive disorder. Evidence that paroxetine may be effective in social anxiety disorder (social phobia) first arose from open-label studies. More recently, three multicentre, randomized, placebo-controlled trials have been performed, each lasting 12 weeks, to assess the efficacy and tolerability of paroxetine in the treatment of social anxiety disorder, and these studies are reviewed here. The data from all three studies consistently demonstrated that paroxetine was effective in reducing both the symptoms of anxiety and the disability and impairment of social anxiety disorder. Paroxetine performed significantly better than placebo on all primary (Liebowitz Social Anxiety Scale, Clinical Global Impression) and secondary (Social Avoidance and Distress Scale, Sheehan Disability Scale) outcome measures. Adverse events were restricted to those already known to be associated with SSRIs, no serious adverse events associated with medication were experienced, and the numbers withdrawing from the studies were not significantly different in the paroxetine and control groups. Taken together, these studies confirm that paroxetine is an effective and well tolerated treatment for patients with social anxiety disorder.

Humans↗
PubMed1999

Apparent bioaccumulation of Mn derived from paper-mill effluent by the freshwater crayfish Cherax destructor--the role of Mn oxidising bacteria.

Bioaccumulation studies of wastewater from a thermo-mechanical paper mill using the freshwater crayfish (Cherax destructor) consistently demonstrated elevated levels of manganese. Most of the Mn appeared to be associated with the carapace of the animals. It is suggested that the elevated Mn levels are the result of Mn-oxidising bacteria forming biofilms on the carapace of the crayfish followed by Mn oxide precipitation rather than active uptake of Mn by the crayfish.

Animals↗
PubMed1999

Attempted suicide in west London, I. Rates across ethnic communities.

BACKGROUND: Two previous studies from the United Kingdom have suggested that rates of attempted suicide in Asian women are higher than in the native population. METHOD: Over a 1-year period we identified 434 patients presenting from one catchment area to four hospitals, after episodes of self-harm. These patients were assessed using the GHQ, CIS-R, and Life Events Inventory, and by collecting details of the attempt itself. RESULTS: Asian women had the highest overall rates; 1.6 times those in White women and 2.5 times the rate among Asian men. The rates were lowest among older women. Among younger Asian women (less than 30 years) the rates were 2.5 times those of White women and seven times those of Asian men. The rates among black groups were lower than expected. Self-poisoning was the commonest method of self-harm. CONCLUSIONS: Younger Asian women are vulnerable to increased rates of attempted self-harm and deserve to be studied further.

Adolescent↗
PubMed1999

Attempted suicide in west London, II. Inter-group comparisons.

BACKGROUND: Previous studies of attempted suicide have suggested that cultural and social factors play a significant role in the causation of deliberate self-harm. METHOD: In order to measure elements of culture conflict two inter-group comparisons were undertaken. In the first, 27 Asian women who had presented to hospital services following attempted suicide (Asian group) were matched with a group of similar age Asian women attending GP surgeries for other reasons (Asian GP attenders group). The second comparison was between the Asian and 46 White attempters. RESULTS: On comparing Asian attempters with Asian GP attenders group the former were more likely to have a history of previous suicidal behaviour, to have a psychiatric diagnosis, and be unemployed. Their parents were more likely to have arrived in the United Kingdom at an older age. In addition, those who attempted suicide were more likely to have been in an inter-racial relationship and to have changed religions. In the second inter-group comparison, the characteristics of Asian and White suicide attempt patients were examined. White attempters were more likely to have mental illness, and were more likely to use alcohol as part of the method of attempted suicide. By contrast, Asian attempters had experienced life events pertaining to relationships, took fewer tablets and yet expressed greater regret at not succeeding in the attempt. CONCLUSIONS: Although numbers are small, social stress and other cultural factors play an important role in the act of deliberate self-harm.

Adolescent↗
PubMed1999

Reboxetine, a selective noradrenaline reuptake inhibitor for the treatment of depression.

Reboxetine is a selective noradrenaline reuptake inhibitor that has been found to be efficacious and tolerable in both short- and long-term treatment of depression. It is a racemic mixture of two enantiomers, the (S,S)-enantiomer being the more potent inhibitor. Reboxetine has little effect on 5-HT or dopamine reuptake, does not inhibit monoamine oxidase activity and has low affinity for alpha-adrenergic and muscarinic receptors. Absorption is rapid and the terminal elimination half-life (13 h) allows twice-daily administration. It shows linear pharmacokinetics which are unaffected by multiple dosing, gender or hepatic insufficiency, although doses should be reduced in elderly patients and in those with severe renal impairment. Reboxetine does not interact with the principal isotypes of the cytochrome P450 system and should have a low potential for drug-drug interactions. Studies in animal models indicate that it has low toxicity.

Journal Article↗