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Biomedical subjects

C Jackson

Publications and source records attributed to C Jackson.

At least 91 records · Page 5Linked to original sources
PubMed1996

Demographic and clinical characteristics of patients with episodic migraine versus chronic daily headache.

We compared data from 243 patients with episodic migraine (EM) and 132 patients with chronic daily headache (CDH). We divided the latter group into those with tension-type headache only (CDH Type 1) and those with headaches having migrainous features (CDH Types 2 + 3) and compared each with the EM group and all three groups with one another. CDH Type 1 patients differed from those in the other groups by virtue of gender (more often male) and mean age at headache onset (older). The CDH Types 2 + 3 and EM groups differed only in that the former were more likely to have undergone a brain-imaging study. These data suggest that CDH Type 1 may represent a distinct headache syndrome, while CDH Types 2 + 3 closely resemble episodic migraine.

Adult↗
PubMed1996

Atypical responses of rat ileum to pindolol, cyanopindolol and iodocyanopindolol.

1. Pindolol, cyanopindolol (CYP) and iodocyanopindolol (IodoCYP) have been reported to act either as antagonists, agonists or partial agonists at the beta 3-adrenoceptor in different preparations. A comprehensive investigation has not yet been described with these compounds tested in one tissue from one species. This study was conducted to delineate the pharmacological effects of pindolol, CYP and IodoCYP and to provide data on their affinities at the predominant beta-adrenoceptor in rat ileum. 2. The beta-adrenoceptors present in rat ileum were characterized in the presence of CGP 20712A and ICI 118 551, atropine and corticosterone, with (-)-isoprenaline used as an agonist. The role of the beta 1 and beta 2-adrenoceptors was determined by the omission of either CGP 20712A, ICI 118 551, or both, from the buffers. Conversely, the effectiveness of the beta 1- and beta 2-adrenoceptor blockade was examined by use of the beta 1-adrenoceptor-selective agonist, RO 363 and the beta 2-adrenoceptor-selective agonist, salbutamol. 3. There was no evidence for the presence of functional beta 1-adrenoceptors, and no strong evidence that beta 2-adrenoceptor stimulation contributed to the relaxant effects of (-)-isoprenaline. (-)-Phenylephrine did not produce relaxation of the tissue and 5-hydroxytryptamine produced contraction. 4. The beta 3-adrenoceptor-selective agonist, BRL 37344 and (-)-isoprenaline were potent full agonists (pD2 8.35 +/- 0.04 and 7.76 +/- 0.14 respectively), whereas ICI D7114 was less potent (pseudo pD2 6.92 +/- 0.15). These results indicate that the predominant functional beta-adrenoceptors in rat ileum are beta 3-adrenoceptors. 5. Partial agonist effects were produced by CYP (pD2 5.28 +/- 0.26) and IodoCYP (pD2 7.0 +/- 0.26), but not pindolol. All three compounds antagonized the effects of (-)-isoprenaline with pKb values of 6.68 +/- 0.10, 7.59 +/- 0.07 and 7.59 +/- 0.11 for pindolol, CYP and IodoCYP respectively. Likewise, CYP and IodoCYP antagonized the effects of BRL 37344 with pKb values of 7.20 +/- 0.22 and 7.21 +/- 0.14 respectively. This study provides the first functional data on the effects of IodoCYP, the ligand with the highest known affinity for the beta 3-adrenoceptor, at the characterized rat ileum beta 3-adrenoceptor. 6. In conclusion, whereas pKb values suggest that CYP and IodoCYP have a similar affinity for the beta 3-adrenoceptor in rat ileum, the higher potency of IodoCYP suggests that it promotes a greater coupling efficiency, or that its partial agonist effects are produced through a site other than the beta 3-adrenoceptor. The similar pKb values for CYP and IodoCYP at the beta 3-adrenoceptor contrast with their order of known affinities at the beta 1- and beta 2-adrenoceptors, where IodoCYP is far more potent than CYP. This provides evidence of further differences in the characteristics of the beta 3-adrenoceptors compared to the beta 1- and beta 2-adrenoceptors. Finally, the utility of IodoCYP as a beta 3-adrenoceptor antagonist would appear to be limited because of the greater magnitude of partial agonist effects that it produces.

Adrenergic beta-Agonists↗
PubMed1996

Early intervention in psychosis: opportunities for secondary prevention.

A description of an emerging paradigm is presented which places emphasis upon secondary prevention in psychosis. It is argued that the first two or three years following a first episode of psychosis is a crucial period for high-quality psychosocial and biological interventions and a time slot which may influence recovery and long-term outcome. Factors contributing to long-term outcome as possible areas for secondary prevention are reviewed.

Female↗
PubMed1996

The impact of legislation to improve coordination of services to children with serious emotional disturbance.

OBJECTIVE: This study evaluated the impact of state legislation in Indiana mandating establishment of local coordinating committees to prevent inappropriate placement of children and youth with serious emotional disturbance out of the home and to facilitate the development of communitybased initiatives. METHODS: In the first stage of the study, a survey was sent to the directors of mental health, welfare, education, and probation agencies of each county to estimate the extent that the structure and processes mandated by law were in place. In the second stage, structured interviews were conducted with the directors of key agencies in seven representative counties. RESULTS: Stage 1 produced 310 completed surveys from all 92 counties; 73 counties had functioning committees. Improved coordination among providers was the most frequently cited reason for the committee's success; half of the respondents felt that the committee resulted in better services. More than half reported that too few service options were available. Other problems cited were rigid funding opportunities that limited options and lack of staff time to attend and prepare for meetings. Interviewees in the second stage noted that the committee too often formalized already-made decisions, that consideration of individual cases came too late in the process, and that in many cases less restrictive options had already been tried unsuccessfully. They also noted that the committee process had not achieved its major objective of pooling resources to address the needs of particular children. CONCLUSIONS: Adequate funding and a fiscal strategy to support coordination and staffing of local coordinating committees are critical to their successful implementation.

Affective Symptoms↗
PubMed1996

Assessing for glaucoma in general practice.

Examining patients appropriately for primary open angle glaucoma in the general practice setting has traditionally been extremely difficult. The authors review important issues in the early detection of primary open angle glaucoma and discuss new assessment tools to assist GPs in this area.

Acute Disease↗
PubMed1996

Initiation of cigarette smoking among children with and without learning disabilities.

The goals of this study were to determine if: (1) children with learning disabilities should be included in school-based smoking prevention programs and (2) existing prevention curricula are appropriate for children with learning disabilities. Initiation of cigarette smoking and several correlates of smoking, including personal attribute, peer influence, and parent influence variables, were measured in a sample of 1470 3rd and 5th grade children. The rates of smoking initiation were 17% and 15% for children with and without learning disabilities, respectively. In addition, several of the known correlates of smoking among youth, including low self-control, negative orientation toward school, and peer smoking, were also significantly associated with smoking by children with learning disabilities. Children with learning disabilities are as much in need of smoking prevention programs as children without learning disabilities. Although current smoking prevention curricula address issues relevant to children with learning disabilities, additional research is needed to identify the special needs of these children and to determine the type of smoking prevention program most likely to be effective with them.

Age Factors↗
PubMed1995

Reducing anxiety in new dental patients by means of leaflets.

Fifty adults, consecutive attenders at a dentist who was new to them, were selected. They completed the Spielberger State Anxiety Inventory before and after they had read one of two different leaflets in the waiting room. One, the informative leaflet, included information about pain control and stop signals. A comparison leaflet did not include this information but acknowledged, sympathetically, that many people are nervous of dental treatment. The leaflet also provided some explanations for that fear. Both leaflets were designed, according to published evidence, to be easily read and understood. The layout drew attention to the most important points. State Anxiety decreased significantly only in the patients who read the informative leaflet (P < 0.01). This occurred before the patients met their new dentist. Those patients given the informative leaflet rated it as much more helpful than those given the comparison leaflet (P = 0.007).

Adolescent↗
PubMed1995

Complete nucleotide sequence of a gene prtR of Porphyromonas gingivalis W50 encoding a 132 kDa protein that contains an arginine-specific thiol endopeptidase domain and a haemagglutinin domain.

We have purified from Porphyromonas gingivalis W50 a 45 kDa arginine-specific, thiol-activated, EDTA-sensitive endopeptidase, designated prtR. Oligonucleotide probes based on the N-terminal amino acid sequence were used to isolate a genomic fragment containing an open reading frame (3654 bp) with the potential to encode a 132 kDa protein including the prtR N-terminus. Analysis of this prtR gene revealed that the predicted nascent product contains a protease domain followed by a haemagglutinin domain and is post-translationally processed by proteolytic (possibly autolytic) events to produce a 43-54 kDa arginine-specific, thiol protease and a 41-53 kDa haemagglutinin. Comparison of the prtR with the P. gingivalis prtH gene suggests that the prtH gene product also contains protease and haemagglutinin domains but in the reverse order to that in the prtR. An overlapping but shifted reading frame at the 3' end of the prtR encodes the 5' region of the prtH.

Amino Acid Sequence↗
PubMed1995

The theme of death in the French and German literature on eating disorders.

It is not widely appreciated in the English-speaking world that a number of articles written in French and German do address the role played by death preoccupations and concerns in the development and maintenance of eating disorders, particularly anorexia nervosa. In previous published articles these important "hidden" threads have been highlighted in examining in some detail, the writings of the German authors Binswanger, Von Weizsäcker, and Thomä. In this article, the writings of other German authors are also briefly reviewed as well as the French authors Bensoussan, Fouraste, Raimbault, and Thouzery-Loras. Implications and issues are posed for both the researchers and clinicians alike contributing to the literature in English on eating disorders, who do not necessarily embrace these themes in therapy and who may not reflect their significance to theory in the literature itself.

Anorexia Nervosa↗
PubMed1995

Effects of BDNF on dopaminergic, serotonergic, and GABAergic neurons in cultures of human fetal ventral mesencephalon.

The neurotrophin brain-derived neurotrophic factor (BDNF) was tested for its ability to promote the survival and regulation of expression of phenotypic markers of dopaminergic, serotonergic, and GABAergic neurons in free-floating roller tube cultures of human fetal ventral mesencephalon. This culture system contains neurons of the anlage of the substantia nigra as well as that of the rostral raphe nucleus. Dopaminergic neuron number and tyrosine hydroxylase (TH) fiber density was monitored by TH immunocytochemistry. Measurement of dopamine (DA) content, TH enzymatic activity, serotonin (5-HT) content, and glutamic acid decarboxylase (GAD) activity were used as indices of their respective neurotransmitter function. The presence of GABAergic and serotonergic neurons in this culture system was confirmed by GABA and 5-HT immunocytochemistry. In cultures maintained in the presence of BDNF (10 ng/ml), the density of TH-positive cells was increased by 2.5-fold (P F 0.05), and the TH-positive fiber density was increased by 3.5-fold (P F 0.01), relative to control cultures. Similarly, the relative increases in DA content and TH activity were 2.6- and 2.3-fold, respectively, in the BDNF-treated cultures (P F 0.01 and P F 0.01). On a per neuron basis, DA content and TH activity were not markedly changed by BDNF treatment, suggesting that the increases in DA content and TH activity are due to more DA neurons surviving. Relative elevations were also observed in serotonin content (2.0-fold, P F 0.01) and GAD enzymatic activity (1.4-fold, P F 0.01). Future studies will need to determine whether these changes result from the direct action of BDNF on these neurons or through some indirect mechanism. The results demonstrate that BDNF has beneficial effects on cultured human fetal tissue, which may be relevant in optimizing neuronal transplantation techniques, and that multiple systems are simultaneously influenced by BDNF.

Abortion, Induced↗
PubMed1995

Lipid peroxidation contributes to age-related membrane rigidity.

The aim of this work was to assess the relative contributions of lipid peroxidation and cholesterol content to the increase in membrane rigidity observed during senescence. Membrane fluidity was manipulated through exposure to peroxidized or cholesterol-loaded liposomes. Small unilamella liposomes were prepared and either peroxidized by Fe(++)-ADP-ascorbic acid or loaded with cholesterol. After incorporation of the liposomes into rat liver microsomal membranes, membrane fluidity was quantitated by measuring changes in polarization. Membranes exhibited a greater sensitivity to peroxidation than cholesterol in that incorporation of peroxidized liposomes induced microsomal membrane rigidity substantially more than did cholesterol-loaded liposomes. Thus it is proposed, based on data from the present and earlier studies, that membrane fluidity can be modulated readily by lipid peroxidation of membrane phospholipids, irrespective of the influences of cholesterol. These results support the proposal that alterations of lipid structure are more potent and effective than compositional changes in cholesterol in inducing age-related increases in membrane rigidity.

Aging↗
PubMed1995

Protection of the germinal epithelium in the rat from the cytotoxic effects of chemotherapy by a luteinizing hormone-releasing hormone agonist and antiandrogen therapy.

OBJECTIVES: The protection of spermatogenesis during chemotherapy using an antiandrogen and a luteinizing hormone-releasing hormone (LHRH) agonist was examined in the rat. Previous studies using LHRH agonists alone have been inconclusive, as both protective and deleterious effects on the germinal epithelium have been reported. Flutamide has not previously been used in this manner but theoretically should protect the germinal epithelium, since flutamide rapidly blocks testosterone at the cellular level and also minimizes the testosterone "flare" when LHRH agonist therapy is initiated. METHODS: Mature Sprague-Dawley rats were pretreated with flutamide, sustained-release goserelin acetate (Zoladex), or a combination of flutamide and sustained-release goserelin acetate for 14 days before 4 weekly doses of procarbazine were initiated. The seminiferous tubules were evaluated histologically after a 90-day regeneration period using the stem cell assay test. RESULTS: After treatment with procarbazine alone, only 43% of the seminiferous tubules were active; however, 80% were active if protected with flutamide, 91% if protected with sustained-release goserelin acetate, and 95% if protected with both flutamide and goserelin acetate. CONCLUSION: Flutamide, sustained-release goserelin acetate, and a combination of these agents were effective in protecting the germinal epithelium of the rat during chemotherapy. A combination of flutamide and goserelin acetate provided the best protection. This study demonstrates for the first time the protective effect of flutamide and flutamide with goserelin acetate on the germinal epithelium during chemotherapy.

Animals↗
PubMed1995

Screening for glaucoma in a Brisbane general practice--the role of tonometry.

OBJECTIVES: (1) To pilot, and evaluate, a tonometry training intervention for general practitioners; (2) to evaluate the efficacy of three types of tonometer (Perkins, Schiotz and Tonopen) in the hands of these general practitioners; (3) to evaluate the predictive value of tonometry in screening for glaucoma in a general practice population; and (4) to evaluate the acceptability of tonometry to general practice patients. DESIGN: After being trained, three general practitioners recruited 73 of their patients over 50 years of age to attend for measurement of intraocular pressure by tonometry. Intraocular pressure was initially measured by an ophthalmologist using the Goldmann applanation tonometer, and then recorded in random order by GPs using three types of tonometer--the Perkins, Schiotz and Tonopen. SETTING: A group general practice in a middle-class suburb in southern Brisbane. OUTCOME MEASURES: (1) Comparison of measurements on the Perkins, Schiotz and Tonopen tonometers with that of the 'gold standard', the Goldmann Applanation tonometer; (2) prevalence of disc and perimetric abnormality suggestive of glaucoma among those patients with increased intraocular pressure; and (3) the acceptability of contact tonometry to general practice patients. RESULTS: There was considerable variability between intraocular values obtained across doctors and across instruments (6% to 95% of values within 4 mm of the 'gold standard'). The Schiotz tonometer provided the most uniform assessment of intraocular pressure across the groups. Nineteen of the 73 patients (26%) had intraocular pressures > or = 21 mmHg using the 'gold standard'. Of these, 18 were followed up with funduscopy, gonioscopy, repeat measurement of intraocular pressure and visual field assessment. Five had persistent elevations of intraocular pressure > or = 21 mmHg on subsequent assessment, and two had mild abnormalities of cup-disc ratio with normal fields on testing with Humphrey computerised perimetry. CONCLUSION: No one hand-held tonometer proved highly accurate in the hands of all three doctors. Even measured optimally, increased intraocular pressure alone was a poor predictor of glaucoma. Of the population screened, two patients (3%) showed evidence of mild cup-disc abnormality requiring follow-up.

Australia↗
PubMed1995

Brisbane GPs' perceptions of screening for primary open-angle glaucoma.

BACKGROUND: Primary open-angle glaucoma (POAG) is one of the three leading causes of blindness in Australia, often causing considerable visual field loss before the patient becomes symptomatic. Recent years have seen a quickening of public health interest in primary open-angle glaucoma. Our study evaluates the attitudes and skills of Brisbane GPs with regard to screening for POAG. OBJECTIVES: To evaluate general practitioners' current use of possible screening modalities for POAG. To evaluate general practitioners' attitudes to screening for POAG. To evaluate general practitioner's levels of satisfaction with their knowledge and skills in the diagnosis of common ophthalmological conditions. METHOD: A questionnaire was distributed to 130 randomly selected GPs in the Brisbane metropolitan area. Response rate was 94%. RESULTS: Tonometry and funduscopy were infrequently used in Brisbane general practice. Only 15% of the sample were satisfied with their current knowledge and skills concerning the detection of POAG. 88% felt that patients > 50 years should be screened for POAG and nominated a variety of sources -75% advocating ophthalmology screeners, 65% GP screeners, and 41% optometrist screeners. Ninety-nine per cent believed ophthalmologists should be treating glaucoma patients, and 57% believed GPs should have a role in management. Only 1% supported a therapeutic role for optometrists. Major perceived barriers to glaucoma screening in the elderly were the inaccuracy of current general practice screening tools (65%) and paucity of information concerning the desirability of screening (32%). CONCLUSION: Brisbane general practitioners believe patients > 50 years old should be screened for POAG. They advocated a role for screening by ophthalmologists, GPs and optometrists. Major perceived barriers to current screening in general practice are the inaccuracy of current general practice tools (65%) and paucity of information on the subject (32%). The majority (85%) requested further information and provision of skills in this area.

Attitude of Health Personnel↗
PubMed1995

Model for the neuromuscular complications of systemic lupus erythematosus.

The purpose of this study is to evaluate nerve and muscle physiology and histopathology in a murine lupus model. Muscle strength, compound muscle action potentials (distal latency and amplitude), proximal limb muscle, sciatic nerve and joint specimens were studied in MRL/lpr (lupus model) and MRL/++ (control) mice. MRL/lpr mice showed decreased muscle strength (P < 10(-6, Wilcoxon rank sum), lower compound muscle action potential mean amplitude and prolonged distal latency (P = 0.005 and 0.042. Mann-Whitney U-test), and muscle and nerve inflammation (P = 0.002 and P = 0.037, Fisher's exact test) compared with MRL/++ mice. The MRL/lpr strain evaluated in this study demonstrated muscle weakness, abnormal motor nerve conduction studies and inflammation of both muscle and nerve. These features make it an excellent model for studying the neuromuscular complications of lupus.

Action Potentials↗