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Biomedical subjects

J Webb

Publications and source records attributed to J Webb.

At least 55 records · Page 3Linked to original sources
PubMed1998

The form of iron oxide deposits in thalassemic tissues varies between different groups of patients: a comparison between Thai beta-thalassemia/hemoglobin E patients and Australian beta-thalassemia patients.

Mössbauer spectra of 12 beta-thalassemia/hemoglobin E spleen samples from Thai patients who had not received multiple blood transfusions and chelation therapy and seven beta-thalassemia spleen samples from Australian patients who had received multiple blood transfusions and chelation therapy were recorded with sample temperatures of 78 K. Each spectrum was found to consist of a superposition of a relatively intense central doublet characteristic of high-spin Fe(III), a low intensity sextet of peaks due to magnetic hyperfine-field splitting, and occasionally a doublet that could be attributed to heme iron. A significant (P=0.01) difference (Kolmogorov-Smirnov statistic of 0.71) between the distributions of sextet signal intensity as a fraction (Fs) of the total non-heme iron Mössbauer spectral signal for the two groups of patients was detected. The distribution of Fs for the Thai beta-thalassemia/hemoglobin E spleens had a mean value of 0.128 (S.D. 0.035) while that for the Australian beta-thalassemia spleens had a mean of 0.27 (S.D. 0.12). No significant difference between the distributions of non-heme iron concentrations in the tissues for the two groups of patients was detected by atomic absorption spectrometry. This study shows that the Australian beta-thalassemia patients had a higher fraction of their non-heme spleen iron in a goethite-like form than the Thai beta-thalassemia/Hb E patients.

Chelation Therapy↗
PubMed1998

Do first impressions count? A comparison of subjective and psychologic assessment of spinal patients.

Psychologic factors may have a major influence on the outcome of treatment for back pain. Psychologic disturbance is manifest as emotional distress and may be associated with inappropriate symptoms and signs. Few outcome studies describe the patient population in terms of their psychologic profile. Anecdotal evidence suggested that the routine use of psychologic screening tests in British spine practice was rare. An audit of the prevalent use of psychologic testing amongst a selected group of British spinal surgeons was conducted. This was followed by a prospective, double blind comparison of subjective evaluations of patients with formal psychologic tests. The principal aim was to determine how accurately treating physicians could identify psychologically distressed patients. A postal questionnaire was sent to all consultant members of the British Orthopaedic Spine Society. Details of their current practice and frequency of use of psychologic tests was obtained. In a subsequent study, 125 consecutive new patients attending a back pain clinic were initially evaluated by questionnaires and classified as either psychologically distressed or non-distressed. These patients were then interviewed and examined by treating physicians, who then allocated them to one of four psychologic categories, using predefined criteria. The two results were compared and sensitivity, specificity and predictive values for the subjective evaluations were calculated. Sixty-three percent of respondents to the postal survey either never or only occasionally used any form of psychologic testing in assessing back pain patients. The follow-up prospective study demonstrated that experienced spinal surgeons achieved only a 26% sensitivity when trying to identify distressed patients. The specificity for identifying non-distressed patients was 96%. The predictive value of a "distressed" evaluation was 69%. The predictive value for non-distressed patients was 77%. Subjective psychologic assessment of back pain patients has a low sensitivity and predictive value for distressed patients. Formal psychologic screening should be routinely included in the clinical decision making process.

Attitude of Health Personnel↗
PubMed1998

A familial case of X chromosome deletion ascertained by cytogenetic screening of women with premature ovarian failure.

The association between X chromosome deletions and premature ovarian failure is well established. Previous anecdotal reports however, have not documented the prevalence of X deletions in women with premature ovarian failure. We therefore performed cytogenetic analyses on 79 women with primary or secondary amenorrhoea to assess the utility of screening for a genetic marker for familial premature ovarian failure. A normal karyotype was found in 77 women. One woman with primary amenorrhoea had an XY karyotype and a woman with secondary amenorrhoea had a deletion at Xq 26.1. This second case had a family history of premature ovarian failure, and her mother who underwent premature ovarian failure at 28 years shared this deletion. The early diagnosis of familial X deletions causing premature ovarian failure allowed for the prediction of impending menopause and the implementation of manoeuvres to advance conception. Although cytogenetic aberrations are rare in secondary amenorrhoea, the ability to predict premature ovarian failure can be vital.

Adult↗
PubMed1998

Fragile X premutation screening in women with premature ovarian failure.

We have screened 132 women with premature ovarian failure for fragile X (FRAXA) premutations. Three out of 23 (13%) pedigrees with the familial premature ovarian failure and 3/106 (3%) of women with the sporadic form of premature ovarian failure have FRAXA premutations compared with an expected prevalence of 1:590 (P=0.02). The mechanism of the association between FRAXA premutations and premature ovarian failure is unknown but as a genetic marker, FRAXA screening will be particularly valuable in predicting premature ovarian failure in some pedigrees and in the identification of families at risk of transmitting fragile X syndrome.

Adult↗
PubMed1998

Studies of FRAXA and FRAXE in women with premature ovarian failure.

Recent reports suggest that women with FRAXA premutations have an increased likelihood of having premature ovarian failure (POF). We screened 147 women with idiopathic POF for the number of trinucleotide repeats at the FRAXA and FRAXE loci. We found six women with FRAXA premutations, including four familial and two sporadic cases, but no women with FRAXA full mutations. At the FRAXE locus there were no pre- or full mutations but there was an excess of small alleles with fewer than 11 repeats, including at least one small deletion at or near the triplet. The association of FRAXA premutations with POF confirms that premutation alleles can affect ovarian development or function or both.

Alleles↗
PubMed1997

The effect of histological processing on the form of iron in iron-loaded human tissues.

Iron-loaded human spleen tissue was immersed in neutral buffered formalin over a period of 200 days. Over the first 60 days, iron leached steadily from the tissue until 3% had been lost. Thereafter, no further iron leaching was detected. Comparisons of Mossbauer spectra of freeze-dried tissue and tissue freeze-dried after immersion in formalin for 200 days showed no evidence of chemical transformation of the iron remaining in the tissue. The spectra indicated a difference in the heme-iron to non-heme iron ratio between the two samples probably reflecting inhomogeneity of the ratio throughout the spleen as measured on the centimetre scale. Mossbauer spectra of freeze-dried samples of iron-loaded human liver and pancreas tissue were compared with those for samples from the same patient that had been processed by routine hospital procedures for histology and archival. These spectra showed no evidence for chemical transformation of the iron present in the tissues. These results demonstrate that it is feasible to use archived fixed and embedded human tissue samples for studies aimed at gauging the relative fraction of goethite-like hemosiderin present in the tissue.

Formaldehyde↗
PubMed1997

Pullback atherectomy with the Arrow-Fischell atherectomy device.

The Arrow-Fischell pullback atherectomy catheter is designed to circumferentially debulk and retrieve coronary atheroma. We performed pullback atherectomy before balloon angioplasty or stenting in 41 patients. The device crossed the target lesion in 38 (93%) and obtained tissue in 36 (88%). All procedures were completed successfully and without myocardial infarction, emergency cardiac surgery, or death. Complications included major spasm in 8 patients, postprocedural abrupt closure in 1, and otherwise uncomplicated arterial perforation in 2. Pullback atherectomy can be performed relatively safely, but is more difficult than balloon angioplasty, obtains less tissue than directional atherectomy, and is associated with significant limitations.

Aged↗
PubMed1997

Reproductive toxicity and toxicokinetics of lindane in the male offspring of rats exposed during lactation.

1. Reproductive toxicity and toxicokinetics of lindane during lactation were studied. For the reproductive toxicity study the dams were treated with a single dose of 6 mg/kg on day 9 or 14 of lactation, or with 1 mg/kg on days 9 to 14 of lactation. The male offspring were investigated at puberty and adulthood. For the toxicokinetic study, two groups of dams were treated with 6 mg/kg on day 9 or 14 of lactation. The concentration of lindane was measured in maternal plasma and milk, as well as in male offspring organs. 2. At adulthood, testicular weight and the number of sperm and spermatids were significantly reduced in all treated groups. 3. The testosterone level of the groups treated with 6 mg/ kg was significantly reduced to approximately 50% at puberty as well as in adulthood. In the group treated with 1 mg/kg, the testosterone level was in both age periods reduced, however, only at puberty was the reduction statistically significant. 4. The concentration of lindane in the testis was similar to that found in brain and was half the concentration found in the liver. 5. Histologically some areas of the testis exhibited distinct alterations ranging from small changes to a pronounced effect. 6. Exposure to lindane during lactation induces reproductive hazards to male offspring rats which are detectable at adulthood.

Animals↗
PubMed1997

Asthma in Greenwich, UK: impact of the disease and current management practices.

A great deal of the care of patients with asthma takes place in general practices. The aim of the present study was to describe the impact of asthma in the community and to identify current asthma self-management practices. A two-part questionnaire survey was conducted in a random sample (23%; n=24,398) of persons aged 16-50 yrs, registered with one of the 41 general practices in Greenwich, London, UK. The two parts were: a screening questionnaire identifying persons with current asthma (defined as waking with shortness of breath in the last 12 months, attack of asthma in the last 12 months, or currently taking treatment for asthma); and an asthma questionnaire (completed by those with asthma) assessing quality of life, frequency of asthma symptoms, possession and use of self-management tools, and action in the event of an exacerbation of asthma. The crude response rate was 51%, but this may be an underestimate due to errors in the sampling frame. The prevalences of wheeze and asthma in the past 12 months were 26% and 14%, respectively. Among asthma patients: 43% reported symptoms occurring three or more times per week, and 20% were woken by asthma symptoms on three or more nights per week; most had asthma with a mild impact on quality of life; 26% used inhaled steroids on most days in the preceding month; 16% had a peak flow meter at home; and 7% had oral steroids available. Of the 44% of subjects with asthma, who could identify an exacerbation of asthma in the preceding 6 months: 19% had used a peak flow meter during the episode; 19% had changed their treatment without first being told to do so by a doctor; and 50% had sought urgent medical help. Smokers used less appropriate asthma management and subjects whose asthma had a severe impact on quality of life used more treatment and peak flow monitoring. In conclusion, the prevalence of asthma among adults in Greenwich, UK, has increased since a similar survey in 1986. Many people have fairly mild asthma and a smaller number have severe disease. Much remains to be done to promote appropriate strategies for self-management of asthma exacerbations.

Adolescent↗
PubMed1997

The short form-36 health survey questionnaire in spine surgery.

The Short Form-36 (SF-36) health questionnaire has been put forward as a general measure of outcome in health care and has been evaluated in several recent studies in the UK. We report its use in three groups of patients after spinal operations and have compared it with the Oswestry and Low Back Pain disability scales. There was a significant correlation between all variables of the SF-36 and the low-back scores. The mental-health items had the weakest correlation. Our study shows that the SF-36 questionnaire is valid and has internal consistency when applied to these patients.

Adolescent↗
PubMed1997

Effect of rotational atherectomy on quality of life.

OBJECTIVE: To evaluate whether percutaneous coronary rotational atherectomy (RA) improves quality of life. DESIGN: Prospective sequential study of the first 20 patients who had RA at St Paul's Hospital, Vancouver from November 1993 to April 1994. SETTING: Tertiary care teaching hospital. PATIENTS: There were nine males and 11 females with a mean age of 68 +/- 9.3 years. All had angina pectoris with type B or C coronary lesions. INTERVENTIONS: RA was performed using the Rotablator device. RESULTS: The procedure was angiographically successful in 20 patients and clinically successful in 18 patients. Two patients who sustained acute myocardial infarctions underwent coronary bypass surgery. Before RA there was one patient in Canadian Cardiovascular Society angina class I, five patients in class II, 12 in class III, and two in class IV. At six months' follow-up there were 11 patients in class I, seven in class II and two in class III. The mean Duke Activity Status Index improved from 21.3 +/- 15.8 (mean +/- SD) before the procedure to 36.9 +/- 15.8 (P < 0.001) at six months' follow-up. The consumption of anti-anginal medications also decreased. CONCLUSIONS: RA was associated with improved functional status and quality of life in patients having angina pectoris with type B or C coronary lesions.

Aged↗
PubMed1996

Multicenter clinical experience with the development of a novel short coronary stent and its prototype device.

Our initial experience with the Micro Stent PL and its prototype intracoronary stent is described. A total of 206 stents were implanted in 84 patients for threatened closure or restenosis following balloon angioplasty. The stenting procedure was successful and uncomplicated in 83 of 84 patients. Potential advantages of this particular stent relate to its short length, low surface area, expandability over a range of diameters, radiopacity, low profile, and ease of delivery.

Angioplasty, Balloon, Coronary↗
PubMed1996

Spontaneous coronary artery dissection in young women.

Spontaneous dissection of the coronary arteries is quite rare. It is usually a catastrophic event with fatal outcome. We report two interesting cases of spontaneous dissection whose presentations exemplify the variable course the disorder may take. The first is the only report to our knowledge associated with aerobic exercise; the second is the only reported attempt at treatment with intracoronary thrombolysis.

Adolescent↗