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Biomedical subjects

J Evans

Publications and source records attributed to J Evans.

At least 163 records · Page 9Linked to original sources
PubMed1999

An examination of verbal working memory capacity in children with specific language impairment.

This study investigated verbal working memory capacity in children with specific language impairment (SLI). The task employed in this study was the Competing Language Processing Task (CLPT) developed by Gaulin and Campbell (1994). A total of 40 school-age children participated in this investigation, including 20 with SLI and 20 normal language (NL) age-matched controls. Results indicated that the SLI and NL groups performed similarly in terms of true/false comprehension items, but that the children with SLI evidenced significantly poorer word recall than the NL controls, even when differences in nonverbal cognitive scores were statistically controlled. Distinct patterns of word-recall errors were observed for the SLI and NL groups, as well as different patterns of associations between CLPT word recall and performance on nonverbal cognitive and language measures. The findings are interpreted within the framework of a limited-capacity model of language processing.

Child↗
PubMed1999

Lower abdominal wall reconstruction using the anterior thigh fasciocutaneous flap.

Full thickness defects of the lower abdominal wall are uncommon. They can occur in congenital abdominal wall defects, acute trauma and following resection of soft tissue tumours. In reconstruction of defects not amenable to primary closure, three problems need to be addressed: (i) the fascial layer needs to be reconstructed; (ii) stable and sensate skin coverage is needed as the lower abdominal waistline area is subject to pressure; (iii) it is desirable to restore the contour of the abdominal wall. We present a case with a large area of radiation dermatitis and recurrence of a malignant ovarian tumour in the lower abdominal wall. After en bloc resection the 25 x 6 cm lower abdominal defect was reconstructed with a sensate anterior thigh fasciocutaneous flap. The vascular supply was reliable and the outcome was good. The reasons for using this fasciocutaneous flap in preference to the other options are discussed.

Abdominal Muscles↗
PubMed1999

A possible effect of different light sources on pregnancy rates following gamete intra-fallopian transfer.

A retrospective study of 34 sequential gamete intra-Fallopian transfer (GIFT) procedures suggested a significant effect on pregnancy rates associated with the different laparoscopic light sources, with a pregnancy rate of 50% in 22 cycles using a halogen light source and 9% in 12 cycles using a xenon light source. Other explanatory variables were explored, but none was to have a significant effect on the pregnancy rate. Further investigation revealed that the xenon light source emitted more ultraviolet light than the conventional halogen light source--suggesting a possible detrimental effect of ultraviolet light on the gametes in the GIFT procedure.

Adult↗
PubMed1999

Lyme disease.

Lyme disease (LD) is the most common tick-borne disease in the United States. The overall trend has been an average annual increase in reported cases since surveillance was initiated by the Centers for Disease Control and Prevention in 1982. Ixodes ticks often carry more than one potential pathogen, and co-infection with Borrelia burgdorferi and other organisms has been reported. The impact of dual infection upon the clinical course of LD is not known. Further studies of erythema migrans-like rashes in the Southern United States have indicated that it is likely caused by a related spirochetal organism. Case reports of unusual presentations have broadened our understanding of the clinical spectrum of LD. Studies in patients with chronic Lyme arthritis have indicated that an autoimmune process may be responsible for such cases. Results of two large, placebo-controlled trials of a recombinant Lyme vaccine have been reported and results indicate that the vaccine is safe and effective in preventing LD in adults.

Adult↗
PubMed1999

Criterion-based validity of an intracarotid amobarbital recognition-memory protocol.

PURPOSE: We tested whether the behavioral components of an Intracarotid Amobarbital Protocol (IAP) had criterion validity. It was hypothesized that a recognition-memory test designed for intracarotid injections and used to predict the risk of global amnesia before an elective temporal lobectomy should also identify persons who are severely amnesic due to other neurologic causes. Divergent validity predicts that speech tasks would be unaffected by amnesia. Test-retest reliability also was measured. METHODS: Fifteen persons with severe amnesia were administered four alternate forms of a yes/no recognition-memory protocol and a speech protocol. No drug injection occurred. Standardized neuropsychological tests were used to divide the amnesic group into those with Global Amnesia (i.e., retain no ongoing memories), Severe Amnesia (i.e., memory impaired), and Amnesia Plus (severe amnesia plus other neuropsychologic deficits). RESULTS: Two persons with Global Amnesia obtained scores at or below chance (i.e., failed) on the memory protocol. Unexpectedly, 12 of 13 severely amnesic persons obtained near-perfect memory scores. Amnesia had no impact on the speech protocol. Pass/Fail outcomes were highly correlated across all four sets. CONCLUSIONS: A four-item IAP memory protocol showed good reliability and criterion validity in identifying the rare condition of Global Amnesia, but it was insensitive to other disabling, severe amnesic disorders. This IAP memory protocol might have validity in predicting a postsurgical Global Amnesic disorder, but it did not identify and therefore could not predict other more common severe amnesic disorders.

Adolescent↗
PubMed1999

Comparative analysis of two meningococcal immunotyping monoclonal antibodies by resonant mirror biosensor and antibody gene sequencing.

Lipooligosaccharide (LOS) is a major surface component of the cell walls of Neisseria meningitidis, which is important for its roles in pathogenesis and antigenic variation, as a target for immunological typing, and as a possible vaccine component. Although the structures of many antigenic variants have been determined, routine immunological typing of these molecules remains problematic. Resonant mirror analysis was combined with gene sequencing to characterize two monoclonal antibodies (MAbs) used in typing panels that were raised against the same LOS immunotype, L3,7,9. The two MAbs (MAb 4A8-B2 and MAb 9-2-L379) were of the same immunoglobulin subtype, but while MAb 9-2-L379 was more than a 1,000-fold more sensitive in immunotyping assays of both whole meningococcal cells and purified LOS, MAb 4A8-B2 was more specific for immunotype L3,7,9. The differences in sensitivity were a consequence of MAb 9-2-L379 having a 44-fold-faster association constant than MAb 4A8-B2. Comparison of the amino acid sequences of the variable chains of the MAbs revealed that they had very similar heavy chains (81% amino acid sequence identity) but diverse light chains (54% sequence identity). The differential binding kinetics and specificities observed with these MAbs were probably due to differences in the epitopes recognized, and these were probably a consequence of the different immunization protocols used in their production.

Amino Acid Sequence↗
PubMed1999

Topographic and keratometric astigmatism up to 1 year following small flap trabeculectomy (microtrabeculectomy).

AIM: To determine the induced corneal astigmatism by measuring the changes in manual keratometry and computerised corneal videokeratoscopy up to 1 year following small flap trabeculectomy (microtrabeculectomy). METHOD: A prospective study of a case series of small flap trabeculectomy procedures performed at the 90 degree meridian on 16 eyes of 16 patients, all followed to 1 year postoperatively. Changes in manual keratometry and computerised videokeratoscopy (Eyesys) readings were analysed by vector analysis and vector decomposition techniques. RESULTS: By vector analysis, the mean surgically induced refractive change (SIRC) cylinder power vectors induced at 1, 3, 6, and 12 months as measured by manual keratometry were 0.68, 0.38, 0.52, and 0.55 dioptres, and by keratography 0.75, 0.66, 0.59, and 0.64 dioptres. Vector decomposition on the induced vector cylinders on manual keratometry resulted in a "with the rule" mean vector of 0.52 and 0.22 dioptres at 1 and 3 months and an "against the rule" mean vector of 0.16 and 0.16 dioptres at the same time points (p=0.03 and 0.28 respectively). Vector decomposition at 6 and 12 months revealed no significant with the rule changes induced. Similar analysis on the videokeratoscopy results revealed significant induced with the rule astigmatism until 3 months, but not at 6 and 12 months postoperatively. CONCLUSION: Small flap trabeculectomy (microtrabeculectomy) produces smaller changes in corneal curvature that resolve sooner than previous reports of larger flap techniques.

Aged↗
PubMed1999

Angiotensin II type 1 receptor antisense gene therapy prevents altered renal vascular calcium homeostasis in hypertension.

Intracellular Ca2+ ([Ca2+]i) homeostasis regulates vascular smooth muscle tone, and alteration in [Ca2+]i handling is associated with the development and establishment of hypertension. We have previously established in the spontaneously hypertensive rat (SHR) that virally mediated delivery of angiotensin II type 1 receptor antisense (AT1R-AS) prevents the development of high blood pressure and some pathophysiology associated with hypertension for 120 days. In light of this, our objectives in this study were to determine whether AT1R-AS gene therapy (1) could have a longer duration in the prevention of hypertension and (2) would attenuate the alterations in renal vascular Ca2+ homeostasis and therefore vasoconstriction, characteristics of hypertension. Intracardiac delivery of AT1R-AS in neonates prevented the development of hypertension in SHR for at least 210 days. At this time, untreated SHR renal resistance arterioles showed a significantly enhanced contractile response to KCl and angiotensin II (Ang II) when compared with normotensive Wistar-Kyoto rats. In addition, L-type Ca2+ current density and Ang II-dependent increases in [Ca2+]i were significantly increased in cells dissociated from renal resistance arterioles of the untreated SHR. AT1R-AS treatment prevented all of the above vascular alterations associated with the hypertensive state in SHR. Finally, Western blot analysis of L-type Ca2+ channel (alpha1C) protein levels in renal resistance arterioles of untreated SHR showed no significant difference when compared with control. These results are novel and demonstrate that viral-mediated delivery of AT1R-AS not only attenuates the development of hypertension on a long-term basis but prevents changes in renal vascular Ca2+ homeostasis associated with the disease.

Angiotensin II↗
PubMed1999

The legal and risk management conundrum of telemedicine.

A store-and-forward teledermatology service was established between two general practices and the department of plastic surgery at Derriford Hospital in Plymouth. An academic lawyer and an expert in risk management made an assessment of the service. They looked at the following issues: medicolegal problems; security; confidentiality; and risk. None of them was considered insoluble and there is no reason why such issues should prevent the National Health Service from developing telemedicine services. All organizations considering telemedicine need to ensure that the proposed telemedicine service satisfies the issues raised in this study.

Computer Security↗
PubMed1999

Focal segmental glomerulosclerosis: prognostic implications of the cellular lesion.

The cellular lesion (CELL), seen in some patients with primary focal segmental glomerulosclerosis (FSGS), comprises proliferation, hypertrophy, and pathologic changes in the cells overlying the glomerular scar. The prognosis of the cellular lesion was retrospectively studied in 100 patients with FSGS (43 had FSGS-CELL and 57 had FSGS without the cellular lesion (classic segmental scar [CS]). Patients with the FSGS-CELL lesion were more often black and severely proteinuric and developed more end-stage renal disease (ESRD). Nephrotic patients with FSGS-CELL (n = 39) were more proteinuric at presentation than patients with FSGS-CS (n = 36). ESRD developed more frequently in patients with the FSGS-CELL (17 of 39, 44% versus 5 of 36, 14%, P = 0.005), and patients with extensive FSGS-CELL (> or = 20% glomeruli) were mainly black (94%), severely nephrotic (67%, >10 g/d), and had a poor response to treatment (23% remission). In nephrotic patients, initial serum creatinine, interstitial expansion > or = 20%, and CELL independently predicted ESRD. However, the rates of remission in treated nephrotic patients with FSGS-CELL and FSGS-CS were the same (9 of 17, 53% versus 17 of 39, 52%), and patients in both groups who achieved a remission had a 5-yr survival of 100%. Steroid treatment was the only variable that predicted remission. Patients with the FSGS-CELL have an increased prevalence of ESRD, but the improved prognosis associated with remission is so significant that a therapeutic trial is warranted in all nephrotic FSGS patients, regardless of the presence of the cellular lesion.

Adult↗
PubMed1999

Rofecoxib [Vioxx, MK-0966; 4-(4'-methylsulfonylphenyl)-3-phenyl-2-(5H)-furanone]: a potent and orally active cyclooxygenase-2 inhibitor. Pharmacological and biochemical profiles.

The discoveries that cyclooxygenase (COX)-2 is an inducible form of COX involved in inflammation and that COX-1 is the major isoform responsible for the production of prostaglandins (PGs) in the gastrointestinal tract have provided a rationale for the development of specific COX-2 inhibitors as a new class of anti-inflammatory agents with improved gastrointestinal tolerability. In the present study, the preclinical pharmacological and biochemical profiles of rofecoxib [Vioxx, also known as MK-0966, 4-(4'-methylsulfonylphenyl)-3-phenyl-2-(5H)-furanone], an orally active COX-2 inhibitor, are described. Rofecoxib is a potent inhibitor of the COX-2-dependent production of PGE(2) in human osteosarcoma cells (IC(50) = 26 +/- 10 nM) and Chinese hamster ovary cells expressing human COX-2 (IC(50) = 18 +/- 7 nM) with a 1000-fold selectivity for the inhibition of COX-2 compared with the inhibition of COX-1 activity (IC(50) > 50 microM in U937 cells and IC(50) > 15 microM in Chinese hamster ovary cells expressing human COX-1). Rofecoxib is a time-dependent inhibitor of purified human recombinant COX-2 (IC(50) = 0.34 microM) but caused inhibition of purified human COX-1 in a non-time-dependent manner that could only be observed at a very low substrate concentration (IC(50) = 26 microM at 0.1 microM arachidonic acid concentration). In an in vitro human whole blood assay, rofecoxib selectively inhibited lipopolysaccharide-induced, COX-2-derived PGE(2) synthesis with an IC(50) value of 0.53 +/- 0.02 microM compared with an IC(50) value of 18.8 +/- 0.9 microM for the inhibition of COX-1-derived thromboxane B(2) synthesis after blood coagulation. Using the ratio of the COX-1 IC(50) values over the COX-2 IC(50) values in the human whole blood assay, selectivity ratios for the inhibition of COX-2 of 36, 6.6, 2, 3, and 0.4 were obtained for rofecoxib, celecoxib, meloxicam, diclofenac, and indomethacin, respectively. In several in vivo rodent models, rofecoxib is a potent inhibitor of carrageenan-induced paw edema (ID(50) = 1.5 mg/kg), carrageenan-induced paw hyperalgesia (ID(50) = 1.0 mg/kg), lipopolysaccharide-induced pyresis (ID(50) = 0.24 mg/kg), and adjuvant-induced arthritis (ID(50) = 0.74 mg/kg/day). Rofecoxib also has a protective effect on adjuvant-induced destruction of cartilage and bone structures in rats. In a (51)Cr excretion assay for detection of gastrointestinal integrity in either rats or squirrel monkeys, rofecoxib has no effect at doses up to 200 mg/kg/day for 5 days. Rofecoxib is a novel COX-2 inhibitor with a biochemical and pharmacological profile clearly distinct from that of current nonsteroidal anti-inflammatory drugs and represents a new therapeutic class of anti-inflammatory agents for the treatment of the symptoms of osteoarthritis and rheumatoid arthritis with improved gastrointestinal tolerability.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗