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1.
S Afr J Sports Med ; 35(1): v35i1a15218, 2023.
Article in English | MEDLINE | ID: mdl-38249770

ABSTRACT

In sports, the value and mutual benefit of university-stakeholder partnerships have been well-recognised. It has been argued that cricket has a unique set of challenges compared to other team sports. In 2016, the South African Cricketers' Association (SACA) and the University of Cape Town established a partnership to (i) conduct novel research on professional cricketers and (ii) ensure SACA programmes and initiatives are informed by said research and/or the currently available literature. As the demand on professional cricketers has increased, so has the interest in their career transitioning. That is, how do professional cricketers manage stressors created by changes (or non-changes) throughout their playing careers? To help identify gaps for intervention as a cricketer transitions through their professional career, the purpose of this short report is to describe how a university-stakeholder partnership developed a career transitioning screening tool for professional cricketers in South Africa.

2.
S Afr J Sports Med ; 35(1): v35i1a16097, 2023.
Article in English | MEDLINE | ID: mdl-38249774

ABSTRACT

Cannabidiol (CBD) and Tetrahydrocannabinol (THC) have become easily available to athletes over the years. Using these substances may inadvertently expose an athlete to the possibility of an adverse analytical finding (a "positive" test) and a sanction. Athletes need to understand the risk of an anti-doping rule violation or adverse analytical finding should these products be used, especially if no therapeutic use exemption exists. This position statement attempts to clarify the use of CBD and THC and their associated risks with Anti-Doping Rule Violations (ADRV) in the athletic population. The South African Sports Medicine Association supports this position statement.

3.
Eur J Sport Sci ; 22(2): 269-278, 2022 Feb.
Article in English | MEDLINE | ID: mdl-33210564

ABSTRACT

Rugby league carries a high injury incidence with 61% of injuries occurring at tackles. The ball carrier has a higher injury incidence than the defender, therefore understanding mechanisms occurring during injurious tackles are important. Given the dynamic, open nature of tackling, characteristics influencing tackle outcome likely encompass complex networks of dependencies. This study aims to identify important classifying characteristics of the tackle related to ball carrier injurious and non-injurious events in rugby league and identify the characteristics capability to correctly classify those events. Forty-one ball carrier injuries were identified and 205 matched non-injurious tackles were identified as controls. Each case and control were analysed retrospectively through video analysis. Random forest models were built to (1) filter tackle characteristics possessing relative importance for classifying tackles resulting in injurious/non-injurious outcomes and (2) determine sensitivity and specificity of tackle characteristics to classify injurious and non-injurious events. Six characteristics were identified to possess relative importance to classify injurious tackles. This included 'tackler twisted ball carrier's legs when legs were planted on ground', 'the tackler and ball carrier collide heads', 'the tackler used body weight to tackle ball carrier', 'the tackler has obvious control of the ball carrier' 'the tackler was approaching tackle sub-maximally' and 'tackler's arms were below shoulder level, elbows were flexed'. The study identified tackle characteristics that can be modified in attempt to reduce injury. Additional injury data are needed to establish relationship networks of characteristics and analyse specific injuries. Sensitivity and specificity results of the random forest were 0.995 and 0.525.


Subject(s)
Athletic Injuries , Football , Athletic Injuries/epidemiology , Athletic Injuries/etiology , Athletic Injuries/prevention & control , Football/injuries , Humans , Retrospective Studies , Rugby , Video Recording
4.
S Afr J Sports Med ; 33(1): v33i1a9313, 2021.
Article in English | MEDLINE | ID: mdl-36816904

ABSTRACT

Background: In rugby league (RL), the ability to repeatedly engage in the tackle, whether as a ball carrier or tackler, is essential for team success and player performance. It is also the leading cause of injury, with over 90% of total injuries occurring during the tackle in professional and amateur cohorts. To effectively reduce the risk of injury and optimise performance, establishing the extent of the 'problem', through injury surveillance or descriptive performance studies is required. Objective: The purpose of this narrative synthesis was to systematically search and synthesise tackle injury epidemiology and tackle performance frequency in RL. To achieve this objective, a systematic review was conducted. Methods: The search was limited to English-only articles published between January 1995 and October 2018. Based on the search criteria, a total of 53 studies were found: 32 focused on tackle injury epidemiology (nine cases studies) and 21 focused on tackle frequency. Results: In general, over 600 tackles may occur during an RL match. Tackle injury frequencies (both overall and time-loss injuries) ranged between 47%-94% at the professional level, and between 38%-96% for the lower levels of play. A greater proportion of injuries occurring in professional RL are severe time-loss injuries when compared to lower levels of play. Most time-loss and overall injuries occur to players who are tackled, i.e., ball carriers, across all levels of play. Conclusion: This narrative synthesis will facilitate tackle injury prevention and performance research in RL, and act as a reference document for coaches and practitioners.

5.
S Afr J Sports Med ; 32(1): v32i1a8615, 2020.
Article in English | MEDLINE | ID: mdl-36818959

ABSTRACT

The COVID-19 pandemic causes widespread anxiety and uncertainty regarding disease transmission. In many countries people are obliged to wear a face mask in public spaces. Individuals involved in sports participation at any level need to make informed decisions on wearing a face mask during exercise. Currently there is no scientific evidence on what to advise regarding the safety of wearing a face mask during exercise, or what type of mask to use. This short report aims to answer these questions in a structured and practical way.

6.
BMC Public Health ; 19(1): 1018, 2019 Jul 29.
Article in English | MEDLINE | ID: mdl-31357977

ABSTRACT

BACKGROUND: Cervical cancer treatment and care services have remained largely centralized in Zimbabwe thereby entrenching inequities to access amongst patients. The objective of this study was to investigate the determinants of access to treatment and care among women with cervical cancer in Harare, Zimbabwe. METHODS: A sequential explanatory mixed methods design was used. In phase 1, three surveys (namely community, patient and health worker) were conducted with sample sizes of 143, 134 and 78 participants respectively. Validated structured questionnaires programmed in Android tablet with SurveytoGo software were used for data collection during the surveys. Univariate, bivariate and multivariate logistic regression analyzes were conducted using STATA® version 14 to generate descriptive statistics and identify determinants of access to cervical cancer treatment and care. In phase 2, 16 in-depth interviews, 20 key informant interviews and 6 focus groups were conducted to explain quantitative data. Participants were purposively selected and saturation principle was used to guide sample sizes. Manually generated thematic codes were processed in Dedoose software to produce final outputs for qualitative study. RESULTS: Knowledge of causes (p = 0.046), perceptions of adequacy of specialists (p < 0.001), locus of control (p = 0.009), service satisfaction (p = 0.022) and walking as a means of reaching nearest health facilities (p < 0.001) were associated with treatment or perceptions of access by healthy women. Perceptions of access to treatment amongst health workers were associated with their basic training institution (p = 0.046), health service quality perceptions (p = 0.035) and electricity supply status in their respective health facilities (p = 0.036).Qualitative findings revealed health system, societal and individual factors as barriers to accessing treatment and palliative care. CONCLUSIONS: There are numerous prevailing multi-dimensional barriers to accessing cervical cancer treatment and palliative care in a low -income setting. The findings of this study revealed that heath system and societal factors were more important than individual level factors. Multi-sectoral approaches are recommended to address all the multifaceted barriers in order to improve cervical cancer treatment and palliative care access for better outcomes in resource-limited contexts.


Subject(s)
Health Services Accessibility , Palliative Care/statistics & numerical data , Patient Acceptance of Health Care/statistics & numerical data , Uterine Cervical Neoplasms/therapy , Adult , Female , Focus Groups , Humans , Middle Aged , Qualitative Research , Socioeconomic Factors , Zimbabwe
7.
J Sci Med Sport ; 21(6): 631-634, 2018 Jun.
Article in English | MEDLINE | ID: mdl-29097230

ABSTRACT

OBJECTIVES: The tackle event in rugby union ('rugby') contributes to the majority of players' injuries. Referees can reduce this risk by sanctioning dangerous tackles. A study in elite adult rugby suggests that referees only sanction a minority of illegal tackles. The aim of this study was to assess if this finding was similar in youth community rugby. DESIGN: Observational study. METHODS: Using EncodePro, 99 South African Rugby Union U18 Youth Week tournament matches were coded between 2011 and 2015. All tackles were coded by a researcher and an international referee to ensure that laws were interpreted correctly. The inter- and intra-rater reliabilities were 0.97-1.00. A regression analysis compared the non-sanctioned rates over time. RESULTS: In total, 12 216 tackles were coded, of which less than 1% (n=113) were 'illegal'. The majority of the 113 illegal tackles were front-on (75%), high tackles (72%) and occurred in the 2nd/4th quarters (29% each). Of the illegal tackles, only 59% were sanctioned. The proportions of illegal tackles and sanctioning of these illegal tackles to all tackles improved by 0.2% per year from 2011-2015 (p<0.05). CONCLUSIONS: In these youth community rugby players, 59% of illegal tackles were not sanctioned appropriately. This was better than a previous study in elite adult rugby, where only 7% of illegal tackles were penalised. Moreover, the rates of illegal tackles and non-sanctioned illegal tackles both improved over time. However, it is critical that referees consistently enforce all laws to enhance injury prevention efforts. Further studies should investigate the reasons for non-sanctioning.


Subject(s)
Athletic Injuries/prevention & control , Football/standards , Punishment , Youth Sports/standards , Football/injuries , Humans , Regression Analysis , South Africa
8.
Exp Physiol ; 98(1): 233-44, 2013 Jan.
Article in English | MEDLINE | ID: mdl-22636255

ABSTRACT

Animals subjected to maternal separation stress during the early stages of development display behavioural, endocrine and growth factor abnormalities that mirror the clinical findings in anxiety/depression. In addition, maternal separation has been shown to exacerbate the behavioural deficits induced by 6-hydroxydopamine (6-OHDA) in a rat model of Parkinson's disease. In contrast, voluntary exercise reduced the detrimental effects of 6-OHDA in the rat model. The beneficial effects of exercise appeared to be largely due to compensation in the non-lesioned hemisphere. The aim of the present study was to investigate whether voluntary exercise for 3 weeks could reverse the effects of maternal separation in rats challenged with the neurotoxin 6-OHDA infused into the medial forebrain bundle after 1 week of exercise, at postnatal day 60. The rats were killed 2 weeks later, at postnatal day 74. Their brains were dissected and the hippocampus rapidly removed for proteomic analysis by isobaric tagging (iTRAQ) and quantification of peptides by matrix-assisted laser desorption/ionization tandem mass spectrometry (MALDI-MS/MS). Maternal separation upregulated hippocampal proteins functionally involved in energy metabolism (nucleoside diphosphate kinase B, enolase and triosephosphate isomerase) and synaptic plasticity (α-synuclein, tenascin-R, Ba1-667, brevican and neurocan core protein) in the non-lesioned hemisphere. Exercise reversed many of these changes by downregulating the levels of hippocampal proteins functionally associated with energy metabolism (nucleoside diphosphate kinase B, enolase and triosephosphate isomerase) and synaptic plasticity (α-synuclein, tenascin-R, Ba1-667, brevican and neurocan core protein) in the non-lesioned hemisphere of rats subjected to maternal separation. Exercise and maternal separation therefore appeared to have opposing effects on the hippocampus in the non-lesioned hemisphere of the rat brain. Exercise seemed partly to reverse the effects of maternal separation stress on these proteins in the non-lesioned hemisphere. The partial reversal of maternal separation-induced proteins by exercise in the non-lesioned side sheds some insight into the mechanism by which exercise alters the molecular role players involved in determining the consequences of early life stress.


Subject(s)
Hippocampus/metabolism , Maternal Deprivation , Parkinson Disease/metabolism , Physical Conditioning, Animal/physiology , Animals , Cytoskeletal Proteins/drug effects , Disease Models, Animal , Energy Metabolism/drug effects , Male , Medial Forebrain Bundle/drug effects , Nerve Tissue Proteins/biosynthesis , Oxidopamine , Parkinson Disease, Secondary/chemically induced , Rats , Stress, Psychological/metabolism , Synaptic Transmission/drug effects
9.
Mol Ecol Resour ; 11(5): 935-6, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21777398

ABSTRACT

This article documents the addition of 92 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Anopheles minimus, An. sinensis, An. dirus, Calephelis mutica, Lutjanus kasmira, Murella muralis and Orchestia montagui. These loci were cross-tested on the following species: Calephelis arizonensi, Calephelis borealis, Calephelis nemesis, Calephelis virginiensis and Lutjanus bengalensis.


Subject(s)
Amphipoda/genetics , Anopheles/genetics , Databases, Genetic , Gastropoda/genetics , Microsatellite Repeats/genetics , Moths/genetics , Perciformes/genetics , Animals , Genetic Markers/genetics
10.
West Indian Med J ; 58(4): 341-6, 2009 Sep.
Article in English | MEDLINE | ID: mdl-20099774

ABSTRACT

Thrombolytic therapy has been proven to be beneficial in selected patients with ischaemic strokes. Early diagnosis is paramount because there is a narrow therapeutic window for these patients to derive benefit from thrombolytics. We sought to evaluate the timing of stroke presentations at the University Hospital of the West Indies (UHWI) in order to assess the potential eligibility for definitive therapy A retrospective audit of all consecutive patients who had emergent computed tomographic (CT) scans for suspected ischaemic stroke at the UHWI was performed over a six-month period between February 2006 and July 2006. Data were extracted from the hospital records and analysed using SPSS version 12. There were 331 patients evaluated with brain CT for a clinically suspected stroke during the study period. Complete time documentation and CT scans were available for analysis in 171 patients with ischaemic strokes. The average age was 64.5 years (range +/- SD: 3-98 +/- 19.9 years) with a slight male preponderance (58% vs. 42%). There was considerable pre-hospital delay with 63% of patients presenting more than 12 hours after the onset of symptoms. There were also long inhospital delays. Only 52% of patients were assessed by a physician within an hour of presentation to hospital and only 55% of patients had CT scans completed within three hours of a physician s request. Although thrombolysis is not routinely performed for ischaemic strokes at our institution, sensitization of physicians and the general public in our setting to symptoms and signs of this disease is urgently needed to improve stroke management, whereby definitive treatment can be considered for selected patients.


Subject(s)
Stroke/drug therapy , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Retrospective Studies , Stroke/diagnosis , Stroke/diagnostic imaging , Thrombolytic Therapy , Tomography, X-Ray Computed , Young Adult
11.
Psychol Med ; 34(3): 491-8, 2004 Apr.
Article in English | MEDLINE | ID: mdl-15259834

ABSTRACT

BACKGROUND: Major depressive disorder (MDD) has been associated with alterations in immune function. Suppression of natural killer (NK) cell activity (NKCA) reliably characterizes immunological alterations observed in MDD. Antidepressant pharmacotherapy has been associated with modulation of NKCA. Previous investigations into antidepressant modulation of NKCA have not employed randomized double-blind placebo controlled designs. Thus, it is unknown whether treatment-associated changes in immune function are due to drug, placebo, or spontaneous remission effects. The present investigation examined the effect of antidepressant treatment on NKCA utilizing a randomized double-blind placebo controlled experimental design. METHOD: Patients (N = 16) met DSM-IV criteria for MDD and were randomly assigned to drug (N = 8; citalopram, 20 mg/day) or placebo (N = 8) under double-blind conditions. Severity and pattern of depressive symptoms were assessed by the Hamilton Depression Rating Scale (HDRS). NK cell function was measured using a standard chromium-release assay and NK cell number assessed by flow cytometry. HDRS scores, NK cell function, and NK cell numbers were collected at 0, 1, 2 and 4 weeks of treatment. RESULTS: Clinical response was associated with augmented NKCA independent of treatment condition. Failure to respond to treatment resulted in significantly reduced NKCA over treatment interval. CONCLUSIONS: The present results suggest that alterations in the depressive syndrome, regardless of therapeutic modality, may be sufficient to modulate NKCA during antidepressant trials and thus may significantly impact on co-morbid health outcomes in MDD.


Subject(s)
Antidepressive Agents, Second-Generation/therapeutic use , Citalopram/therapeutic use , Depressive Disorder, Major/drug therapy , Depressive Disorder, Major/immunology , Killer Cells, Natural/drug effects , Killer Cells, Natural/immunology , Adult , Antidepressive Agents, Second-Generation/pharmacology , Citalopram/pharmacology , Double-Blind Method , Female , Flow Cytometry , Humans , Male , Middle Aged , Psychiatric Status Rating Scales , Severity of Illness Index , Treatment Outcome
12.
J Laryngol Otol ; 118(2): 117-22, 2004 Feb.
Article in English | MEDLINE | ID: mdl-14979948

ABSTRACT

The contribution of air conduction auditory brainstem response (AC-ABR) testing in the paediatric population is widely accepted in clinical audiology. However, this does not allow for differentiation between conductive and sensorineural hearing loss. The purpose of this paper is to review the role of bone conduction auditory brainstem responses (BC-ABR). It is argued that despite such technical difficulties as a narrow dynamic range, masking dilemmas, stimulus artifact and low frequency underestimation of hearing loss, considerable evidence exists to suggest that BC-ABR testing provides an important contribution in the accurate assessment of hearing loss in infants. Modification of the BC-ABR protocol is discussed and the technical difficulties that may arise are addressed, permitting BC-ABR to be used as a tool in the differential diagnosis between conductive and sensorineural hearing. Two relevant case studies are presented to highlight the growing importance of appropriate management in early identification of hearing loss. It can be concluded that BC-ABR should be adopted as a routine clinical diagnostic tool.


Subject(s)
Bone Conduction/physiology , Evoked Potentials, Auditory, Brain Stem , Neonatal Screening/methods , Diagnosis, Differential , Female , Hearing Loss, Conductive/diagnosis , Hearing Loss, Sensorineural/diagnosis , Humans , Infant, Newborn , Male , Predictive Value of Tests
13.
Alaska Med ; 43(2): 26-31, 2001.
Article in English | MEDLINE | ID: mdl-11436432

ABSTRACT

Our continuing experience with allografts has led us to the firm conclusion that there is a clear place for allografts in the ligamentous reconstruction of the unstable knee. Clearly, issues such as cost and availability will limit allograft usage, however concerns regarding inferior clinical results should not. Our experience and those reported by others, indicates that comparable clinical results can be obtained with the added benefit of reduced surgical morbidity. In all cases meticulous attention must be given to the surgical technique. When surgical accuracy is uniformly obtained, the graft choice becomes less important when considering the sole goal of obtaining ligamentous stability in the knee.


Subject(s)
Arthroplasty/methods , Bone Transplantation , Knee Joint/surgery , Ligaments, Articular/surgery , Tendons/transplantation , Achilles Tendon/transplantation , Humans , Transplantation, Homologous
14.
Neuropsychobiology ; 44(1): 1-6, 2001.
Article in English | MEDLINE | ID: mdl-11408785

ABSTRACT

Major depressive disorder (MDD) is associated with reductions in natural killer cell activity (NKCA), however the mechanism(s) mediating reduced NKCA in MDD has yet to be determined. In light of evidence that MDD is associated with an inflammatory immune response, we propose that reactive oxygen species (ROS), generated by inflammatory leukocytes (monocytes and/or neutrophils), may mediate the suppression of NKCA in MDD. Intracellular levels of monocyte ROS were significantly associated with reductions in NKCA in outpatients (n = 15) diagnosed with MDD. Sleep disturbance was also significantly correlated with reductions in NKCA. Elevated levels of ROS may be an additional characteristic of a subset of depressed patients in whom an inflammatory response persists and elevations in ROS may, in part, mediate the associations observed between MDD, cardiovascular disease, and cancer.


Subject(s)
Depressive Disorder, Major/immunology , Killer Cells, Natural/immunology , Monocytes/immunology , Reactive Oxygen Species/metabolism , Adult , Depressive Disorder, Major/diagnosis , Female , Humans , Immune Tolerance/immunology , Lymphocyte Count , Male , Middle Aged , Neutrophils/immunology , Systemic Inflammatory Response Syndrome/diagnosis , Systemic Inflammatory Response Syndrome/immunology
15.
Int Immunopharmacol ; 1(2): 247-53, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11360926

ABSTRACT

Serotonin (5-hydroxytryptamine; 5-HT) modulates constituents of the immune system. 5-HT1A receptor antagonists potently suppress lymphocyte function. NK cell activity (NKCA) was measured after exposure of mononuclear cells to the 5-HT1A receptor antagonist pindobind and the 5-HT(1C/2) receptor antagonist ketanserin. Elutriated monocytes were exposed to pindobind, incubated with peripheral blood lymphocytes (PBL) in the presence or absence of an H2O2 scavenger catalase, and NKCA measured. Pindobind, but not ketanserin, suppressed NKCA in vitro. Pindobind-treated monocytes suppressed NKCA, whereas pindobind treatment of PBL did not affect NKCA. Catalase inhibited pindobind-induced suppression of NKCA. These data are consistent with previous results that 5-HT modulates NKCA via 5-HT1A receptors on monocytes and suggest that 5-HT may abrogate monocyte suppression of NKCA by inhibiting monocyte signals such as H2O2.


Subject(s)
Catalase/pharmacology , Killer Cells, Natural/drug effects , Monocytes/physiology , Pindolol/analogs & derivatives , Pindolol/pharmacology , Receptors, Serotonin/physiology , Serotonin Antagonists/pharmacology , Cyclohexane Monoterpenes , Humans , Ketanserin/pharmacology , Killer Cells, Natural/immunology , Receptors, Serotonin, 5-HT1
16.
Microb Ecol ; 42(3): 286-294, 2001 Oct.
Article in English | MEDLINE | ID: mdl-12024254

ABSTRACT

Population studies of enteric bacteria in an agriculturally impacted stream (Ledbetter Creek, Murray, Kentucky, USA) were conducted over a period of 2 years. Total number of bacteria, cultivated heterotrophic aerobic bacteria, and enteric bacteria showed significant differences between winter and summer. The cultivated numbers of heterotrophic aerobic bacteria and enteric bacteria were significantly more abundant in summer than in winter. The abundance of enteric bacteria was 12.9% in an upwelling zone and 9.8% in a downwelling zone in summer. Most of the enteric bacterial strains isolated on MacConkey agar were assigned to Enterobacter cloacae and E. agglomerans by API 20E and an analysis of the restriction patterns produced by amplified DNA coding for 16S rRNA (ARDRA) with the enzyme Hpa II. E. cloacae and E. agglomerans genotypes isolated from three hyporheic and gravel bar depth intervals (0-10 cm, 15-25 cm, and 30-40 cm) in summer and fall showed significant spatial variation and were heterogeneously distributed along the stream. Temperature, inorganic nutrients, and occurrence of anoxic zones affected the distribution of enteric bacteria. These techniques can be used as a model to monitor shifts among different species in the stream ecosystem.

17.
Am J Ind Med ; 40(6): 703-9, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11757047

ABSTRACT

BACKGROUND: Each year approximately 30,000 convenience store employees are at risk for injuries related to robberies and many are fatal. METHODS: A prospective cohort study of 460 convenience store robberies from 1 February 1995 to 30 September 1996 was conducted to uncover possible associations between injury and pertinent robbery circumstances and work environments. Data collection sources included police reports, employee interviews, store evaluations, and relevant Census data. Rate ratios and correlation statistics were calculated to identify associations with injury and relationships between variables. RESULTS: Injury risk was strongly associated with the following characteristics: employee resistance, robberies without firearms or money taken, daytime and merchandise robberies, stores with limited escape routes and no cash policy or drop safe, older clerks, and surrounding areas with lower valued buildings, less expensive rent, more vacant structures, and younger residents. Numerous intercorrelations between these characteristics were identified. DISCUSSION: Training opportunities, store procedures, and environmental designs are important factors to consider in reducing robbery-related injuries.


Subject(s)
Commerce/statistics & numerical data , Occupational Diseases/epidemiology , Theft/statistics & numerical data , Wounds and Injuries/epidemiology , Adult , Aged , Cohort Studies , Confidence Intervals , Female , Humans , Incidence , Injury Severity Score , Male , Middle Aged , Occupational Diseases/etiology , Probability , Prospective Studies , Risk Factors , Survival Rate , United States/epidemiology , Wounds and Injuries/etiology
18.
J Neurophysiol ; 84(3): 1531-44, 2000 Sep.
Article in English | MEDLINE | ID: mdl-10980025

ABSTRACT

In rat, chorda tympani nerve taste responses to Na(+) salts increase between roughly 10 and 45 days of age to reach stable, mature magnitudes. Previous evidence from in vitro preparations and from taste nerve responses using Na(+) channel blockers suggests that the physiological basis for this developmental increase in gustatory Na(+) sensitivity is the progressive addition of functional, Na(+) transduction elements (i.e., amiloride-sensitive Na(+) channels) to the apical membranes of fungiform papilla taste receptor cells. To avoid potential confounding effects of pharmacological interventions and to permit quantification of aggregate Na(+) channel behavior using a kinetic model, we obtained chorda tympani nerve responses to NaCl and sodium gluconate (NaGlu) during receptive field voltage clamp in rats aged from 12-14 to 60 days and older (60+ days). Significant, age-dependent increases in chorda tympani responses to these stimuli occurred as expected. Importantly, apical Na(+) channel density, estimated from an apical Na(+) channel kinetic model, increased monotonically with age. The maximum rate of Na(+) response increase occurred between postnatal days 12-14 and 29-31. In addition, estimated Na(+) channel affinity increased between 12-14 and 19-23 days of age, i.e., on a time course distinct from that of the maximum rate of Na(+) response increase. Finally, estimates of the fraction of clamp voltage dropped across taste receptor apical membranes decreased between 19-23 and 29-31 days of age for NaCl but remained stable for NaGlu. The stimulus dependence of this change is consistent with a developmental increase in taste bud tight junctional Cl(-) ion permeability that lags behind the developmental increase in apical Na(+) channel density. A significant, indirect anion influence on apical Na(+) channel properties was present at all ages tested. This influence was evident in the higher apparent apical Na(+) channel affinities obtained for NaCl relative to NaGlu. This stimulus-dependent modulation of apical Na(+) channel apparent affinity relies on differences in the transepithelial potentials between NaCl and NaGlu. These originate from differences in paracellular anion permeability but act also on the driving force for Na(+) through apical Na(+) channels. Detection of such an influence on taste depends fundamentally on the preservation of taste bud polarity and on a direct measure of sensory function, such as the response of primary afferents.


Subject(s)
Aging/metabolism , Amiloride/pharmacology , Chorda Tympani Nerve/physiology , Sodium Channels/metabolism , Sodium/metabolism , Taste Buds/metabolism , Ammonium Chloride/pharmacology , Animals , Dose-Response Relationship, Drug , Female , Gluconates/pharmacology , Male , Patch-Clamp Techniques , Rats , Rats, Sprague-Dawley , Sodium/pharmacology , Sodium Channels/drug effects , Sodium Chloride/pharmacology , Stimulation, Chemical , Taste Buds/drug effects
19.
J Clin Psychopharmacol ; 20(4): 423-7, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10917403

ABSTRACT

Fluoxetine (FLX) has a unique pharmacokinetic profile. Its major metabolite, norfluoxetine (NFLX), possesses FLX's antidepressant efficacy and a half-life of 7 to 15 days, suggesting the possibility of nonstandard dosing strategies. This study examined the tolerability of a weekly dose and its equivalence to daily dosing of FLX for the continuation phase of treatment for major depressive disorder (MDD). One hundred fourteen subjects initially received open-label treatment with 20 mg of FLX daily for 7 weeks. Subsequently, 70 subjects with a score on the Hamilton Rating Scale for Depression (HAM-D) of 12 or less were randomly assigned in a double-blind design to one of three treatment groups: 20 mg FLX daily (N = 21), 60 mg FLX weekly (N = 28), or placebo (N = 21) and were followed for 7 weeks. HAM-D scores and blood levels of FLX and NFLX were analyzed using a repeated-measures analysis of variance. During the double-blind phase, blood levels for both FLX and NFLX differed across the treatment groups, yet no statistically significant difference in HAM-D scores was observed. There was no difference in the dropout rate across the groups. Subjects could not correctly identify the treatment group into which they were assigned. Weekly dosing of FLX seems to be well tolerated and possibly as effective as daily dosing in maintaining the therapeutic response in subjects with MDD.


Subject(s)
Antidepressive Agents, Second-Generation/administration & dosage , Antidepressive Agents, Second-Generation/therapeutic use , Depressive Disorder/drug therapy , Fluoxetine/administration & dosage , Fluoxetine/therapeutic use , Adult , Antidepressive Agents, Second-Generation/blood , Chromatography, High Pressure Liquid , Depressive Disorder/psychology , Double-Blind Method , Female , Fluoxetine/blood , Humans , Male , Middle Aged , Psychiatric Status Rating Scales
20.
Pharmacol Biochem Behav ; 66(2): 337-42, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10880687

ABSTRACT

Male rats were treated with fluoxetine (FLX) or vehicle daily for 14 days and copulatory behavior tested on day 15. Rats were either mated to three ejaculations or to sexual exhaustion. Both standard measures and the mount bout analysis were used to evaluate the effects of the chronic FLX on male rat copulatory behavior. Only 56.25% of the animals treated with FLX achieved three ejaculations. FLX inhibited the consumatory aspect of male sexual behavior, especially the ability to achieve three ejaculations, but there was no effect on the propensity of the male to pursue the female. These differences were observed for the first three ejaculations. Analysis of the last three ejaculations in those animals that mated to exhaustion did not reveal an effect of FLX. The behavioral pattern of FLX-treated animals during the first three ejaculations resembled that observed during the last three ejaculatory series in the vehicle-treated animals that mated to exhaustion. The results are discussed in terms of the serotonergic effects on male rat sexual behavior.


Subject(s)
Copulation/drug effects , Ejaculation/drug effects , Fluoxetine/toxicity , Selective Serotonin Reuptake Inhibitors/toxicity , Animals , Appetitive Behavior/drug effects , Appetitive Behavior/physiology , Consummatory Behavior/drug effects , Consummatory Behavior/physiology , Copulation/physiology , Dopamine/physiology , Ejaculation/physiology , Female , Fluoxetine/administration & dosage , Male , Rats , Rats, Sprague-Dawley , Serotonin/physiology , Selective Serotonin Reuptake Inhibitors/administration & dosage , Sexual Behavior, Animal/drug effects , Sexual Behavior, Animal/physiology
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