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Biomedical subjects

A Heald

Publications and source records attributed to A Heald.

At least 19 recordsLinked to original sources
PubMed2006

A cross-sectional study to investigate long-term cognitive function in people with treated pituitary Cushing's disease.

INTRODUCTION: It has been proposed that exposure to high levels of endogenous steroids in untreated pituitary Cushing's disease damages hippocampal structures leading to impairment in learning and memory processes. We hypothesised that patients with treated pituitary Cushing's disease would perform significantly worse on tests of cognitive ability than those with nonfunctioning pituitary adenomas. DESIGN: Sixteen adults with pituitary Cushing's disease (PCD) and 16 adults with non-functioning pituitary adenomas (NFA) undertook the following comprehensive neuropsychological assessments: National Adult Reading Test (NART: premorbid abilities), California Verbal Learning Test (CVLT 2 UK: learning and recall), Stroop (executive functioning), Trail-Making Test (TMT: executive functioning and attention), Adult Memory and Information Processing Battery (AMIPB: Information Processing Speed and Story Recall subtests). RESULTS: There was no significant difference in premorbid IQ scores (NFA mean=101 SD=13; PCD mean=102, SD=13), in verbal learning nor any significant difference in the percentage of verbal material retained in story recall (AMIPB). Performance on higher executive tasks Stroop and TMT and on measures of information processing was similar. However, there were significant decrements between some mean scores for both groups and published normative data with a clear association between higher HADS depression scores and impaired objective memory and attention which was not specific to PCD. CONCLUSIONS: We found no difference in cognitive function between patients with PCD and NFA. The results suggest a discrepancy between patients' subjective perception of functional cognitive impairments and objective findings on psychometric testing and point to the influence of affective symptoms on cognitive performance, particularly in Cushing's disease.

Adult↗
PubMed2005

Diabetes and ethnic minorities.

The global prevalence of diabetes for all age groups is estimated to be 2.8%. Type 2 diabetes accounts for at least 90% of diabetes worldwide. Diabetes incidence, prevalence, and disease progression varies by ethnic group. This review highlights unique aspects of the risk of developing diabetes, its overwhelming vascular complications, and their management mainly using data among South Asians and African-Caribbeans in the UK but also using non-UK data. It is concluded that although the origin of the ethnic differences in incidence need further clarification, many factors should be amenable to prevention and treatment in all ethnic groups worldwide.

Chronic Disease↗
PubMed2000

Progestins abrogate estrogen-induced changes in the insulin-like growth factor axis.

OBJECTIVE: We sought to investigate the effect of oral progestins on estrogen-mediated changes in the insulin-like growth factor axis in the peripheral circulation. STUDY DESIGN: Oral conjugated equine estrogen alone or in combination with medroxyprogesterone acetate, desogestrel, or norethindrone was given in a randomized triple-crossover fashion to 10 healthy postmenopausal women, and the effects on the insulin-like growth factor axis were determined. RESULTS: Baseline circulating insulin-like growth factor I levels were significantly reduced by conjugated equine estrogen (359 +/- 54 vs 225 +/- 44 ng/mL; P =.0001). This effect was reversed by progestins (medroxyprogesterone acetate, 254 +/- 44 ng/mL; desogestrel, 266 +/- 50 ng/mL; norethindrone, 286 +/- 48 ng/mL; F = 12.2; P =.0015). Free insulin-like growth factor I was reduced by conjugated equine estrogen (1.00 +/- 0.15 ng/mL vs 2.10 +/- 0.39 ng/mL; P =.004), but addition of progestogens had no further effect. Insulin-like growth factor II and insulin levels were unaffected by conjugated equine estrogen or progestins. Plasma insulin-like growth factor binding protein 1 concentration increased significantly from baseline with conjugated equine estrogen alone (44.1 +/- 6.0 vs 154 +/- 30 microg/L; P =.003). This rise was opposed by progestins of increasing androgenicity (medroxyprogesterone acetate, 130 +/- 26 microg/L; desogestrel, 100 +/- 16 microg/L; norethindrone, 78.0 +/- 12 microg/L; F = 12.5; P =.0015). Insulin-like growth factor binding protein 3 levels fell with conjugated equine estrogen, and this was reversed by progestins (conjugated equine estrogen, 2.17 +/- 0.13 mg/L; vs norethindrone and conjugated equine estrogen, 2.41 +/- 0.12 mg/L; F = 7.6; P =.01). Insulin-like growth factor binding protein 4 levels increased with conjugated equine estrogen with or without progestins, whereas insulin-like growth factor binding protein 2 levels were unchanged. CONCLUSIONS: Coadministration of androgenic progestins abrogates estrogen-related changes in circulating insulin-like growth factor I, insulin-like growth factor binding protein 1, and insulin-like growth factor binding protein 3. Such hormone replacement therapy-induced changes may have significant consequences for the development of cardiovascular disease and osteoporosis and implications for the use of insulin-like growth factor I in monitoring growth hormone replacement.

Cross-Over Studies↗
PubMed1999

Fluorination of 3-(3-(piperidin-1-yl)propyl)indoles and 3-(3-(piperazin-1-yl)propyl)indoles gives selective human 5-HT1D receptor ligands with improved pharmacokinetic profiles.

It has previously been reported that a 3-(3-(piperazin-1-yl)propyl)indole series of 5-HT1D receptor ligands have pharmacokinetic advantages over the corresponding 3-(3-(piperidin-1-yl)propyl)indole series and that the reduced pKa of the piperazines compared to the piperidines may be one possible explanation for these differences. To investigate this proposal we have developed versatile synthetic strategies for the incorporation of fluorine into these ligands, producing novel series of 4-fluoropiperidines, 3-fluoro-4-aminopiperidines, and both piperazine and piperidine derivatives with one or two fluorines in the propyl linker. Ligands were identified which maintained high affinity and selectivity for the 5-HT1D receptor and showed agonist efficacy in vitro. The incorporation of fluorine was found to significantly reduce the pKa of the compounds, and this reduction of basicity was shown to have a dramatic, beneficial influence on oral absorption, although the effect on oral bioavailability could not always be accurately predicted.

Administration, Oral↗
PubMed1999

Synthesis and serotonergic activity of 3-[2-(pyrrolidin-1-yl)ethyl]indoles: potent agonists for the h5-HT1D receptor with high selectivity over the h5-HT1B receptor.

The design, synthesis, and biological evaluation of a novel series of 3-[2-(pyrrolidin-1-yl)ethyl]indoles with excellent selectivity for h5-HT1D (formerly 5-HT1Dalpha) receptors over h5-HT1B (formerly 5-HT1Dbeta) receptors are described. Clinically effective antimigraine drugs such as Sumatriptan show little selectivity between h5-HT1D and h5-HT1B receptors. The differential expression of h5-HT1D and h5-HT1B receptors in neural and vascular tissue prompted an investigation of whether a compound selective for the h5-HT1D subtype would have the same clinical efficacy but with reduced side effects. The pyrrolidine 3b was initially identified as having 9-fold selectivity for h5-HT1D over h5-HT1B receptors. Substitution of the pyrrolidine ring of 3b with methylbenzylamine groups gave compounds with nanomolar affinity for the h5-HT1D receptor and 100-fold selectivity with respect to h5-HT1B receptors. Modification of the indole 5-substituent led to the oxazolidinones 24a,b with up to 163-fold selectivity for the h5-HT1D subtype and improved selectivity over other serotonin receptors. The compounds were shown to be full agonists by measurement of agonist-induced [35S]GTPgammaS binding in CHO cells expressed with h5-HT receptors. This study suggests that the h5-HT1D and h5-HT1B receptors can be differentiated by appropriate substitution of the ligand in the region which binds to the aspartate residue and reveals a large binding pocket in the h5-HT1D receptor domain which is absent for the h5-HT1B receptor. The compounds described herein will be important tools to delineate the role of h5-HT1D receptors in migraine.

Administration, Oral↗
PubMed1996

Effects of antibiotic treatment in the subset of common-cold patients who have bacteria in nasopharyngeal secretions.

BACKGROUND: Upper-respiratory-tract infection is one of the main causes of overuse of antibiotics. We have found previously that bacteria such as Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae can be isolated from the nasopharyngeal secretions of a substantial proportion of adults with upper-respiratory-tract infections. We have assessed the efficacy of co-amoxiclav in patients with common colds but no clinical signs of sinusitis or other indications for antibiotics. METHODS: Between January, 1992 and March, 1994, 314 patients who presented to our outpatient clinic with common colds were enrolled in the double-blind, placebo-controlled study. They were randomly assigned 5 days' treatment with co-amoxiclav (375 mg three times daily) or identical placebo. Clinical examinations were done at enrolment and on day 5-7 to assess outcome (cured, persistent symptoms, worse symptoms). Seven patients were excluded after randomisation, seven did not have nasopharyngeal aspiration, and 12 did not return for followup assessment. FINDINGS: Of 300 patients with nasopharyngeal aspirates, 72 had negative bacterial cultures, 167 had cultures positive only for bacteria unrelated to respiratory infections, and 61 had cultures positive for H influenzae, M catarrhalis, or S pneumoniae. At 5-day follow-up of these culture-positive patients, the distribution of outcome was significantly better among co-amoxiclav-treated (n=30) than placebo-treated (n=28) patients (cured 27 vs 4%; persistent symptoms 70 vs 60%; worse symptoms 3 vs 36%; p=0.001). Patients on co-amoxiclav also scored their symptoms significantly lower than patients on placebo (p=0.008). Among culture-negative patients (n=230), the outcome distribution did not differ between the treatment groups (p=0.392). INTERPRETATION: The majority of patients with upper-respiratory-tract infection do not benefit from antibiotics and side-effects are frequent. However, for the subgroup whose nasopharyngeal secretions contain H influenzae, M catarrhalis, or S pneumoniae, antibiotics are clinically beneficial.

Adult↗
PubMed1995

Dapsone/pyrimethamine may prevent mycobacterial disease in immunosuppressed patients infected with the human immunodeficiency virus.

Dapsone exhibits activity against Mycobacterium tuberculosis and Mycobacterium avium complex (MAC) in vitro. We retrospectively examined the incidence of mycobacterial diseases within a randomized prospective trial of prophylaxis for Pneumocystis carinii pneumonia and toxoplasmosis. Of 501 participants who had not previously had a mycobacterial disease, 274 received dapsone/pyrimethamine (200/75 mg once weekly) and 227 received aerosolized pentamidine (300 mg once every 4 weeks). The median CD4 lymphocyte count was 113/microL, and the median duration of treatment was 369 days. Six cases of tuberculosis, 22 of MAC infection, and 3 of Mycobacterium genavense disease occurred during treatment. Stratified by basement CD4 lymphocyte counts, the annual product-limit incidence of mycobacterial disease was 5% during treatment with dapsone/pyrimethamine vs. 12% during treatment with aerosolized pentamidine for patients whose counts were 0-24/microL, 0 vs. 12% for those whose counts were 25-49/microL, and 7% vs. 9% for those whose counts were 50-99/microL. Adjusted for CD4 lymphocyte counts at start of treatment, the relative risk for patients receiving dapsone/pyrimethamine was 0.47 (95% confidence interval, 0.19-1.16; P = .10). This inexpensive and simple regimen may prevent mycobacterial diseases and warrants further investigation as a means of prophylaxis for multiple opportunistic diseases.

Adult↗
PubMed1995

Once-weekly administration of dapsone/pyrimethamine vs. aerosolized pentamidine as combined prophylaxis for Pneumocystis carinii pneumonia and toxoplasmic encephalitis in human immunodeficiency virus-infected patients.

To evaluate combined prophylaxis for Pneumocystis carinii pneumonia (PCP) and toxoplasmic encephalitis, 533 patients with symptomatic human immunodeficiency virus infection and/or CD4 lymphocyte counts of < 200/microL were randomized to receive dapsone/pyrimethamine (200/75 mg once weekly) or aerosolized pentamidine (300 mg every 4 weeks). The median CD4 lymphocyte count was 110/microL; 47.5% were seropositive for toxoplasma antibodies. The median duration of follow-up was 483 days. In the intent-to-treat analysis, 12 cases of PCP and 14 of toxoplasmic encephalitis occurred in the dapsone/pyrimethamine group and 13 and 20 cases, respectively, in the aerosolized pentamidine group (adjusted relative risk for toxoplasmosis, 0.56; P = .10). However, only two of the 14 cases of toxoplasmic encephalitis in the dapsone/pyrimethamine group developed during actual treatment. The mortality among the two groups was similar. Dapsone/pyrimethamine was not tolerated by 30% of participants. A subanalysis of 240 matched, tolerant patients yielded a relative risk for toxoplasmosis of 0.21 (P = .014), a result favoring the use of dapsone/pyrimethamine. Dapsone/pyrimethamine was as effective as aerosolized pentamidine as prophylaxis for PCP and significantly reduced the incidence of toxoplasmic encephalitis among those participants who tolerated it.

AIDS-Related Opportunistic Infections↗
PubMed1995

Acanthocytosis, retinitis pigmentosa, and pallidal degeneration: a report of three patients, including the second reported case with hypoprebetalipoproteinemia (HARP syndrome).

We describe an example of a variant of Hallervorden-Spatz disease, characterized by hypoprebeta-lipoproteinemia, acanthocytosis, retinitis pigmentosa, and pallidal degeneration (HARP syndrome), in an 18-year-old woman who presented with longstanding intellectual subnormality, night blindness, and a 2-year history of orobuccolingual dystonia causing dysarthria and dysphagia. Investigation showed acanthocytosis and hypoprebetalipoproteinemia, and electroretinograms were typical of tapetoretinal degeneration. T2-weighted MRI showed decreased signal intensity in the pallidal nuclei with central hyperintensity, constituting the "eye-of-the-tiger" sign. The patient's sister and mother have a similar lipid disorder but no retinal or neurologic disease. We also report two patients with clinical and radiologic features similar to those of the patient with HARP syndrome but who had normal lipid studies. These various combinations of components of HARP syndrome may be caused by several distinct genetic diseases or may represent variable manifestations of a contiguous gene defect.

Acanthocytes↗
PubMed1994

[3H]L-694,247 labels the 5-HT1D beta receptor in pig caudate membranes.

This study, carried out in pig caudate membranes, characterises the radioligand binding site labelled with [3H]L-694,247 (2-[5-[3-(4-methylsulphonylamino)benzyl-1,2,4-oxadiazol-5-yl ]-1H-indole-3 - yl]ethylamine). The affinities of 27 standard compounds are consistent with binding to a 5-HT1D recognition site. In addition the results indicate that, under the assay conditions described, [3H]L-694,247 specifically labels the 5-HT1D beta recognition site since ketanserin and ritanserin display a low affinity consistent with their activities at this subtype of the 5-HT1D receptor.

Animals↗
PubMed1994

Measurement of central nervous system activity of systemically administered CCKB receptor antagonists by ex vivo binding.

In the present study we have described an ex vivo binding assay in mice to measure the central nervous system (CNS) activity of systemically administered CCKB receptor antagonists. This assay incorporated a transcardiac perfusion step to remove the residual blood from the brain, which otherwise may result in an overestimation of CNS activity. The benzodiazepine CCKB receptor antagonist L-365,260 had marked CNS activity in this assay following i.v. (ED50 12.0 mg/kg) and p.o. (ED50 20.0 mg/kg) administration, whereas the dipeptoid CCKB receptor antagonist, CI988 exhibited relatively weak CNS activity following i.v. injection (ED50 > 30.0 mg/kg). In contrast, following i.c.v. administration, CI988 potently inhibited ex vivo binding of [125I]Bolton Hunter-CCK-8S to mouse brain. The recently described acidic tetrazole CCKB receptor antagonist, L-368,935 had potent CNS activity with an ED50 of 5.6 mg/kg i.v. and an ED50 of 1.9 micrograms/kg i.c.v. These studies suggest that the weak CNS activity of CI988 following systemic injection may, in part, be due to poor brain penetration and that the ex vivo binding assay is a useful way of assessing the brain penetration of CCKB receptor antagonists.

Analysis of Variance↗
PubMed1994

Becker muscular dystrophy with onset after 60 years.

We report an unusual example of Becker muscular dystrophy in which the patient was asymptomatic until his mid-60s, and diagnosis was not made until he was 67 years old. The patient had the unusual deletion of exons 3 to 9 within an actin-binding region of the dystrophin gene, removal or disruption of which is almost invariably associated with a more severe clinical phenotype. Our case illustrates the danger of drawing conclusions about possibly symptomatic deletions without lifelong follow-up.

Age of Onset↗