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Biomedical subjects

J Lambert

Publications and source records attributed to J Lambert.

At least 55 records · Page 3Linked to original sources

Beneficial effects of a skin tolerance-tested moisturizing cream on the barrier function in experimentally-elicited irritant and allergic contact dermatitis.

In experimentally-induced irritant (ICD) and allergic (ACD) contact dermatitis, an oil-in-water (o/w) cream was applied to investigate its effects on a disturbed barrier function compared to untreated physiological barrier repair. Transepidermal water loss (TEWL) measurements were performed. Before the start of the experiments, the skin tolerance of the cream was examined, revealing the non-irritating characteristics of the ingredients and the absence of any contact allergic patch test reaction. In the ICD study, sodium lauryl sulfate (SLS) patches were applied to the forearms of young female volunteers. Consequently, it was observed that repeated cream application (14 days, 2x/day) significantly improved the TEWL of SLS-damaged skin, leading to a complete recovery on day 15. In the ACD study, disruption of skin barrier function was obtained by a nickel-mediated contact allergy patch (CAP) test. The cream was then applied 2x/day for 4 consecutive days. Assessment of TEWL clearly showed that recovery of the disrupted skin significantly improved after cream application in comparison to untreated barrier repair.

Adult↗

The dilute locus and Griscelli syndrome: gateways towards a better understanding of melanosome transport.

In this review an overview of recent advances in the understanding of melanosome movement within epidermal melanocytes is given. Exploration of the molecular events involved in and determining the process of melanosome transport, as an essential part of human pigmentation, could lead to the identification of agents that augment, or down-regulate the transfer of melanosomes to surrounding keratinocytes. This would present a major breakthrough in the possibilities to influence pigmentation and related disorders, of great concern to some patients. Moreover, melanosome transport offers a good model to study mammalian organelle trafficking and its key players in general.

Alternative Splicing↗

The neurobehavioural rating scale-revised: sensitivity and validity in closed head injury assessment.

OBJECTIVES: To investigate the factor structure and psychometric properties of the neurobehavioural rating scale-revised (NRS-R) and to determine its usefulness in clinical trials. METHODS: A consecutive series of patients sustaining severe closed head injury were evacuated to one of 11 large regional North American trauma centres and entered into a randomised, phase III, multicentre clinical trial investigating the therapeutic use of moderate hypothermia. Acute care personnel were blinded to outcome and outcome personnel were blinded to treatment condition. The Glasgow outcome scale (GOS) was the primary outcome measure. Secondary outcome measures included the disability rating scale (DRS) and the NRS-R. RESULTS: Exploratory factor analysis of NRS-R data collected at 6 months after injury (n=210) resulted in a five factor model including: (1) executive/cognition, (2) positive symptoms, (3) negative symptoms, (4) mood/affect, and (5) oral/motor. These factors showed acceptable internal consistency (0.62 to 0.88), low to moderate interfactor correlations (0.19 to 0.61), and discriminated well between GOS defined groups. Factor validity was demonstrated by significant correlations with specific neuropsychological domains. Significant change was measured from 3 to 6 months after injury for the total score (sum of all 29 item ratings) and all factor scores except mood/affect and positive symptoms. The total score and all factor scores correlated significantly with concurrent GOS and DRS scores. CONCLUSIONS: The NRS-R is well suited as a secondary outcome measure for clinical trials as its completion rate exceeds that of neuropsychological assessment and it provides important neurobehavioural information complementary to that provided by global outcome and neuropsychological measures.

Adult↗

ET(A)-receptor blockade prevents matrix metalloproteinase activation late postmyocardial infarction in the rat.

Endothelin (ET) A (ET(A)) receptors activate matrix metalloproteinases (MMP). Since endothelin-1 (ET) is increased in myocardium late postmyocardial infarction (MI), we hypothesized that stimulation of ET(A) receptors contributes to activation of myocardial MMPs late post-MI. Three days post-MI, rats were randomized to treatment with the ET(A)-selective receptor antagonist sitaxsentan (n = 12) or a control group (n = 12). Six weeks later, there were rightward shifts of the left ventricular (LV) end-diastolic and end-systolic pressure-volume relationships, as measured ex vivo by the isovolumic Langendorff technique. Both shifts were markedly attenuated by sitaxsentan. In LV myocardium remote from the infarct, the activities of MMP-1, MMP-2, and MMP-9 were increased in the post-MI group, and the increases were prevented by sitaxsentan treatment. Expression of tissue inhibitor of MMP-1 was decreased post-MI, and the decrease was prevented by sitaxsentan treatment. Chronic post-MI remodeling is associated with activation of MMPs in myocardium remote from the infarct. Inhibition of ET(A) receptors prevents MMP activation and LV dilation, suggesting that ET, acting via the ET(A) receptor, contributes to chronic post-MI remodeling by its effects on MMP activity.

Animals↗

[A non-infectious pyodermatitis: Pyoderma gangrenosum].

Pyoderma gangrenosum (PG) is a rare chronic inflammatory skin disease characterized by the recurring development of necrotizing and painful ulcers. The skin lesions appear spontaneously or after minor traumatic injuries. Sites of predilection include the lower limbs and the trunk but any part of the body may be affected. PG is not an infectious disease; although the etiology is not completely understood, an immune disturbance is certainly involved. An underlying systemic disorder is associated in up to 50% of the cases, specially inflammatory bowel diseases, arthritis, paraproteinemias and hematologic malignancies. Chronic venous or arterial ulcers as well as bacterial gangrene are the most frequent false diagnoses. A right diagnosis, based upon the distinctive clinical features and a compatible histology, is essential to avoid surgical procedure that often tends to exacerbed the process. Because of its persistent and recurrent nature, systemic long-term therapy based upon corticosteroids associated with sulfones or immunosuppressive agents is required.

Adrenal Cortex Hormones↗

Evaluation of flexible cloth electrodes for electrodermal activity recording.

BACKGROUND: Instrument selection for recording physiological data in flight studies requires careful attention to subject comfort and non-interference with aircrew activities. Several electrode types and recording sites may be used to examine electrodermal activity (EDA). Placement of electrodes on the foot minimizes interference with physical activity and reduces motion artifacts; however, use of conventional, hard-plastic-encased metal (PEM) electrodes within a flight boot can produce discomfort and pressure-induced artifacts. HYPOTHESIS: When applied with proper electrolyte gels, thin, flexible, silver-impregnated cloth electrodes should acquire EDA signals qualitatively similar to those acquired using conventional, PEM electrodes. METHODS: EDA responses evoked by light flashes, auditory stimuli and valsalva maneuvers were recorded with cloth and PEM electrodes simultaneously from both feet of 4 male subjects. Performance of cloth vs. PEM electrodes and variability of signals recorded with the same electrode type were examined by placing pairs of selected electrodes on each foot of the subjects. Placements were balanced with respect to age and handedness of the subject and the number of trials with each electrode type placed on the left or right foot. RESULTS: Qualitatively similar signals were recorded with cloth and PEM electrodes. Cloth electrodes showed more variability between electrodes of the same type. CONCLUSION: For EDA recording, cloth electrodes can perform at least as well as PEM electrodes, making it practical to take advantage of the cloth electrodes' flexibility and lower profile.

Adult↗

[Resurgence of vein perforation surgery: SEPS (subfacial endoscopic perforator surgery)].

The treatment of venous ulcers is a challenge even in this era of modern medicine. The role of incompetent perforating veins in the pathophysiology of venous ulcers has been well documented. Open surgical interruption of incompetent perforating veins (Linton's procedure) may be complicated by important wound healing problems, and has never gained widespread acceptance as a first choice treatment. Recently, an endoscopic technique of subfascial interruption of perforating veins has been developed. This new procedure, with smaller scars and faster recovery, gives promising midterm results. The authors summarize their initial experience with subfascial endoscopic perforating surgery (SEPS) during the last three years (25 cases). They obtained ulcer healing in all cases. At 16 month follow-up, 88% of patients remain ulcer free. Three patients developed a new minor ulceration in the era of lipodermatosclerosis. This less invasive technique is a promising tool in the management of patients with venous ulcer disease.

Endoscopy↗

Immunoassays with rolling circle DNA amplification: a versatile platform for ultrasensitive antigen detection.

We describe an adaptation of the rolling circle amplification (RCA) reporter system for the detection of protein Ags, termed "immunoRCA. " In immunoRCA, an oligonucleotide primer is covalently attached to an Ab; thus, in the presence of circular DNA, DNA polymerase, and nucleotides, amplification results in a long DNA molecule containing hundreds of copies of the circular DNA sequence that remain attached to the Ab and that can be detected in a variety of ways. Using immunoRCA, analytes were detected at sensitivities exceeding those of conventional enzyme immunoassays in ELISA and microparticle formats. The signal amplification afforded by immunoRCA also enabled immunoassays to be carried out in microspot and microarray formats with exquisite sensitivity. When Ags are present at concentrations down to fM levels, specifically bound Abs can be scored by counting discrete fluorescent signals arising from individual Ag-Ab complexes. Multiplex immunoRCA also was demonstrated by accurately quantifying Ags mixed in different ratios in a two-color, single-molecule-counting assay on a glass slide. ImmunoRCA thus combines high sensitivity and a very wide dynamic range with an unprecedented capability for single molecule detection. This Ag-detection method is of general applicability and is extendable to multiplexed immunoassays that employ a battery of different Abs, each labeled with a unique oligonucleotide primer, that can be discriminated by a color-coded visualization system. ImmunoRCA-profiling based on the simultaneous quantitation of multiple Ags should expand the power of immunoassays by exploiting the increased information content of ratio-based expression analysis.

Animals↗

Internet use amongst New Zealand general practitioners.

AIMS: To assess how extensively New Zealand doctors are using medical information on the Internet, and to examine how the new technology is affecting their practice of medicine. METHODS: All general practitioners (GPs) known to be working in Otago and Southland were asked to complete a postal questionnaire regarding their use of the Internet and their impressions of patient use of online medical resources. RESULTS: Of 259 questionnaires mailed out, 168 (65%) were returned by GPs currently in practice. Of those, 114 (68%) said they used the Internet at least monthly. A total of 71% of GPs had patients who indicated they had sought medical information from the Internet. Nearly half of respondents expressed concerns that the Internet could have unwelcome effects on the doctor-patient relationship. CONCLUSIONS: Internet use among New Zealand doctors and patients is widespread, and is likely to have significant impact on medical practice now and in the future. While the potential benefits of the new technology are numerous, the Internet may become a source of conflict between doctors and patients.

Data Collection↗

Changes in muscle strength, muscle fibre size and myofibrillar gene expression after immobilization and retraining in humans.

1. Changes in muscle strength, vastus lateralis fibre characteristics and myosin heavy-chain (MyoHC) gene expression were examined in 48 men and women following 3 weeks of knee immobilization and after 12 weeks of retraining with 1866 eccentric, concentric or mixed contractions. 2. Immobilization reduced eccentric, concentric and isometric strength by 47 %. After 2 weeks of spontaneous recovery there still was an average strength deficit of 11 %. With eccentric and mixed compared with concentric retraining the rate of strength recovery was faster and the eccentric and isometric strength gains greater. 3. Immobilization reduced type I, IIa and IIx muscle fibre areas by 13, 10 and 10 %, respectively and after 2 weeks of spontaneous recovery from immobilization these fibres were 5 % smaller than at baseline. Hypertrophy of type I, IIa and IIx fibres relative to baseline was 10, 16 and 16 % after eccentric and 11, 9 and 10 % after mixed training (all P < 0.05), exceeding the 4, 5 and 5 % gains after concentric training. Type IIa and IIx fibre enlargements were greatest after eccentric training. 4. Total RNA/wet muscle weight and ty I, IIa and IIx MyoHC mRNA levels did not change differently after immobilization and retraining. Immobilization downregulated the expression of type I MyoHC mRNA to 0.72-fold of baseline and exercise training upregulated it to 0.95 of baseline. No changes occurred in type IIa MyoHC mRNA. Immobilization and exercise training upregulated type IIx MyoHC mRNA 2.9-fold and 1.2-fold, respectively. For the immobilization segment, type I, IIa and IIx fibre area and type I, IIa and IIx MyoHC mRNA correlated (r = 0.66, r = 0.07 and r = -0.71, respectively). 5. The present data underscore the role muscle lengthening plays in human neuromuscular function and adaptation.

Adult↗

Amiodarone to prevent recurrence of atrial fibrillation. Canadian Trial of Atrial Fibrillation Investigators.

BACKGROUND: The restoration and maintenance of sinus rhythm is a desirable goal in patients with atrial fibrillation, because the prevention of recurrences can improve cardiac function and relieve symptoms. Uncontrolled studies have suggested that amiodarone in low doses may be more effective and safer than other agents in preventing recurrence, but this agent has not been tested in a large, randomized trial. METHODS: We undertook a prospective, multicenter trial to test the hypothesis that low doses of amiodarone would be more efficacious in preventing recurrent atrial fibrillation than therapy with sotalol or propafenone. We randomly assigned patients who had had at least one episode of atrial fibrillation within the previous six months to amiodarone or to sotalol or propafenone, given in an open-label fashion. The patients in the group assigned to sotalol or propafenone underwent a second randomization to determine whether they would receive sotalol or propafenone first; if the first drug was unsuccessful the second agent was prescribed. Loading doses of the drugs were administered and electrical cardioversion was performed (if necessary) within 21 days after randomization for all patients in both groups. The follow-up period began 21 days after randomization. The primary end point was the length of time to a first recurrence of atrial fibrillation. RESULTS: Of the 403 patients in the study, 201 were assigned to amiodarone and 202 to either sotalol (101 patients) or propafenone (101 patients). After a mean of 16 months of follow-up, 71 of the patients who were assigned to amiodarone (35 percent) and 127 of those who were assigned to sotalol or propafenone (63 percent) had a recurrence of atrial fibrillation (P<0.001). Adverse events requiring the discontinuation of drug therapy occurred in 18 percent of the patients receiving amiodarone, as compared with 11 percent of those treated with sotalol or propafenone (P=0.06). CONCLUSIONS: Amiodarone is more effective than sotalol or propafenone for the prevention of recurrences of atrial fibrillation.

Aged↗

Overweight and obesity in European children and adolescents.

The conclusions of this mini-workshop are not substantially different from those previously published based on the USA experience [9]. This does not necessarily mean that there are no important differences between Europe and the USA, rather it reflects the paucity of data, especially in Europe. Moreover, European data are dominated by studies in Northern and Western European countries, which are closest in economic terms to the USA. This review has not been able to reflect the position in the less economically advantaged parts of Europe where more substantial differences may occur. Together, these reviews have highlighted the limited and inadequate data available on one of the most important and burgeoning public health problems in the world today. There is an urgent need for more research into the fundamental mechanisms of weight gain and effective interventions if we are to prevent the next generation becoming fatter than their parents.

Adolescent↗

Assessment of neuropsychologic impairments after head injury: interrater reliability and factorial and criterion validity of the Neurobehavioral Rating Scale-Revised.

OBJECTIVE: To study interrater reliability and factorial and criterion validity of the Neurobehavioral Rating Scale-Revised (NRS-R). DESIGN: Validity study on persons with traumatic brain injury (TBI) and test-retest reliability study on a randomly selected subset of patients. Factor analyses, kappa statistics, intraclass correlation coefficients, and Cronbach's alphas were used. SETTING: Inpatients from 15 French hospitals, mainly rehabilitation units. Other recruitment sites included a neurology hospital unit and a psychiatry hospital specifically devoted to TBI rehabilitation. PATIENTS: Two hundred eighty-six TBI patients ages 16 to 70 years (convenience sample). RESULTS: For the reliability study, the average of percentages of agreement among the items was 74.3% and the average of kappa statistics was .40. Factor analyses disclosed a maximum likelihood extraction of 5 correlated factors (F), explaining 42.2% of total variance: (F1) deficits in intentional behavior and in memory, (F2) lowering of emotional state, (F3) emotional and behavioral hyperactivation, (F4) lowering of arousal state and of attention, and (F5) language and speech problems. Results support the criterion validity of the factors. Reliability of the factor scores and internal consistencies of factors were very good. CONCLUSIONS: Results describe some important properties of the NRS-R and, through an understanding of its underlying structure and relationships with the patients' clinical characteristics, contribute to the conceptual framework of neuropsychologic impairments after TBI.

Adolescent↗