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Biomedical subjects

R Warren

Publications and source records attributed to R Warren.

At least 127 records · Page 7Linked to original sources
PubMed1994

Stimulation of human scalp papilla cells by epithelial cells.

Evidence for the growth stimulatory properties of human keratinocyte-derived conditioned medium on human scalp dermal papilla cells and a mouse fibroblast cell line (Balb/c 3T3) is presented. There was no mitogenic effect on human keratinocytes. This conditioned medium induced a 2-5-fold increase in mitogenic activity in papilla cells relative to sham-conditioned medium as measured by 3H-thymidine incorporation. The papilla cell growth-stimulating activity of the conditioned medium was sensitive to heat, and from size exclusion the molecular weight was greater than 3000 Da.

3T3 Cells↗
PubMed1994

BS5750.

Explore the source record for details and available documents.

Breast Neoplasms↗
PubMed1994

Pictorial and motion-based depth information during active control of self-motion: size-arrival effects on collision avoidance.

With computer simulations of self-motion, Ss controlled their altitude as they approached a floating object and, after getting as close as possible to the object, tried to "jump" over it without collision. Ss jumped significantly later for small objects, compared with larger objects that were approached from equal distances at equal speeds and were positioned at equal clearance heights. This occurred even when accretion-deletion information was present and when object width and length were varied independently. Results were consistent with studies in which Ss judged a large far approaching object to hit the viewpoint before a small near object that would have arrived sooner (P.R. DeLucia, 1991a, 1991b). Results suggest that pictorial information such as relative size contributes to active collision-avoidance tasks and must be considered in models of perceived distance and time-to-arrival.

Computer Simulation↗
PubMed1994

Initial and long-term results of percutaneous transluminal balloon angioplasty for chronic total occlusions: an analysis of 184 procedures.

BACKGROUND: Coronary angioplasty, although of proven use in partial occlusion, has not been shown to be of similar benefit in chronic total occlusion. AIMS: To assess the utility of coronary angioplasty in chronically totally occluded vessels in patients undergoing angioplasty and to determine the success of TIMI-I flow before angioplasty compared to those patients with TIMI-O flow. METHODS: A group of 178 consecutive patients (from 1984 to 1992), who underwent angioplasty of a chronic occlusion, were analysed. There were 136 males and 42 females with a mean age of 56.9 years. RESULTS: Initial technical success was achieved in 65%. Patients with TIMI-I flow before angioplasty had a higher chance of success (70%) compared to those with TIMI-O flow (53%), p < 0.04. During hospitalisation six patients suffered myocardial infarction (MI), two required surgery and one patient died. During a mean follow-up of 2.8 years the overall survival rate was 95% for the group as a whole. Freedom from coronary surgery was significantly greater in patients with successful angioplasty (93%) than those without (66%, p < 0.002). The above two populations also showed a significant difference in the incidence of angina (35% vs 56%, p < 0.0003). However, the incidence of MI (6% vs 5%, p > 0.5) and cardiac survival (98% vs 94%, p > 0.1) did not differ significantly in the two groups. Restenosis occurred in 63% of the 95 patients (82%) who returned for follow-up angiography. Eighteen of the 59 patients (28%) with restenosis had a reocclusion. CONCLUSION: The success rate for angioplasty of chronic total occlusions is acceptable. Long-term clinical benefit in patients with successful angioplasty is suggested by the high freedom from angina and the lesser need for coronary surgery. No major impact on either the incidence of MI or cardiac survival was noted when patients who had coronary surgery were included, although it must be emphasised that the sample size in this study was insufficient to detect a difference in these outcome variables.

Angioplasty, Balloon, Coronary↗
PubMed1993

Identification of a new receptor subtype for tumor necrosis factor-alpha.

Two distinct receptors, which bind both tumor necrosis factor-alpha and tumor necrosis factor-beta (TNF-alpha and TNF-beta), have been previously identified and cloned from transformed cells. The present study identifies a novel receptor subtype in normal human liver which binds TNF-alpha but not TNF-beta. TNF-alpha but not TNF-beta competes for 125I-TNF-alpha binding and incorporation into affinity-labeled complexes in human liver plasma membranes (HLPM). Antisera to the cloned receptors competed for 125I-TNF-alpha binding to plasma membranes isolated from various transformed cell lines but not to HLPM. However, mRNAs corresponding in size to both known TNF receptors were detected in liver RNA, making it likely that post-transcriptional modifications account for the TNF-alpha specificity of HLPM. These observations suggest that the effects of TNF-alpha and TNF-beta on some normal tissues may be more distinct than previously realized.

Antibodies, Monoclonal↗
PubMed1993

Endocarditis caused by Rochalimaea henselae.

A case of community-acquired, culture-negative, infective endocarditis was diagnosed in a 57-year-old construction worker. Small, pleomorphic gram-negative rods were seen in Brown-Hopps tissue gram stains and Warthin-Starry silver stains. The organism was identified as Rochalimaea henselae by polymerase chain reaction amplification and sequencing of the 16S rDNA gene sequence. This is the first report of infective endocarditis caused by R henselae.

Community-Acquired Infections↗
PubMed1993

Long-term ineffectiveness of suspension material and musculofascial suspensions: a rabbit model.

The literature describes various methods of platysma and SMAS modification to enhance rhytidoplasty. This paper evaluates suspension materials: autogenous fascia and dermis, Gore- Tex, and a nylon suture to elevate the panniculus carnosus in a rabbit model using 15 animals. In the second part of this paper, 16 rabbits were used to evaluate imbrication and advancement techniques of the latissimus dorsi muscle. The ineffectiveness of permanently moving a viable, innervated muscle under tension is discussed.

Animals↗
PubMed1993

Malignant ventricular arrhythmias in patients with mitral valve prolapse and mild mitral regurgitation.

Mitral valve prolapse (MVP) is a common disorder that, in general, has a good prognosis. Rare occasions of sudden death have been reported in patients with MVP and it is presumed that the basis of sudden death is arrhythmic. We report seven patients with moderate to severe MVP and malignant ventricular arrhythmias. All patients had trivial to mild mitral regurgitation and normal left ventricular function. Three patients presented with syncope, two with out-of-hospital cardiac arrest, and three with recurrent palpitations and presyncope. In a mean follow-up period of 2.5 years (range 6 months to 5 years), two patients died suddenly despite successful control of their nonsustained ventricular tachycardia (VT) with sotalol as shown by ambulatory monitoring. Two patients, who had sustained VT despite antiarrhythmic drug therapy, had mitral valve surgery, however, monomorphic VT could be induced in both even after surgery. The arrhythmias in the remaining three patients are controlled on antiarrhythmic drugs. We conclude that a selected subset of patients with MVP, malignant ventricular arrhythmias, and mild mitral regurgitation are at risk of sudden death. Syncope, inferolateral repolarization changes, complex ventricular ectopy, and a markedly myxomatous valve may be pointers to higher risk of sudden death and mitral valve surgery may not provide control of ventricular arrhythmias.

Adult↗
PubMed1993

Understanding women's responses to treatment for cervical intra-epithelial neoplasia.

Laser treatment is held to prevent the development of cervical intra-epithelial neoplasia, or CIN, into invasive carcinoma of the cervix. Recent work has found that such treatment represents a considerable emotional upset in the lives of many women. In this study, the impact of treatment was further investigated, using a control group to separate the effects of diagnosis from those of treatment. The main findings showed that the diagnosis of CIN is traumatic. Women experience high levels of intrusive thoughts and avoidance, and in response to perceived threats to their health, and existing beliefs about themselves, they also experience high levels of anger. An impact of treatment over and above that of diagnosis was not found. From the interview data, diagnosis has its traumatic impact through women's understanding of CIN's association with cervical cancer, a potentially life-threatening disease. Interview data also suggest that body image and sexual relationships suffer following diagnosis because of CIN's postulated causal relationship to the sexually transmitted wart virus. Fear of the progression of CIN to cervical cancer is consistent with the medical model which provides the rationale for preventative laser treatment. It is speculated that once women are diagnosed as having CIN, the spectre of cancer is raised and their anxiety may be such that being monitored and not immediately treated may cause them great distress.

Adult↗
PubMed1993

Comparative evaluation of detection assays for Chlamydia trachomatis.

The performances of a commercial nucleic acid hybridization test (Gen-Probe Pace 2 Chlamydia trachomatis) and two commercial enzyme immunoassays (EIAs) (Abbott Chlamydiazyme and Pharmacia Chlamydia EIA) were evaluated against cell culture for the detection of C. trachomatis infection, with cervical swabs obtained from 1,037 women visiting a public sexual health center. The positivity rate by cell culture was 4.7%. Sensitivity and specificity for each test were as follows: Gen-Probe, 95.8 and 98.3%; Chlamydiazyme, 80.4 and 99.3%; Pharmacia EIA, 80.8 and 99.1%. Analysis of discrepant results with probe confirmation assay (Gen-Probe) and direct immunofluorescence (Syva Microtrak) revealed 12 cases of C. trachomatis infection for which culture was negative, resulting in the definition of a true-positive case as opposed to a culture positive. The positivity rate by true-positive definition was 5.9%, and sensitivity and specificity for each test were as follows: Gen-Probe, 96.7 and 99.6%; Chlamydiazyme, 77.5 and 100%; Pharmacia EIA, 77.0 and 100%; cell culture, 80.0 and 100%. We conclude that the Gen-Probe Pace 2 C. trachomatis test is a sensitive and specific alternative to cell culture for the detection of C. trachomatis.

Bacteriological Techniques↗
PubMed1993

Rapid prenatal diagnosis of chromosomal aneuploidies by fluorescence in situ hybridization: clinical experience with 4,500 specimens.

Detection of chromosome aneuploidies in uncultured amniocytes is possible using fluorescence in situ hybridization (FISH). We herein describe the results of the first clinical program which utilized FISH for the rapid detection of chromosome aneuploidies in uncultured amniocytes. FISH was performed on physician request, as an adjunct to cytogenetics in 4,500 patients. Region-specific DNA probes to chromosomes 13, 18, 21, X, and Y were used to determine ploidy by analysis of signal number in hybridized nuclei. A sample was considered to be euploid when all autosomal probes generated two hybridization signals and when a normal sex chromosome pattern was observed in greater than or equal to 80% of hybridized nuclei. A sample was considered to be aneuploid when greater than or equal to 70% of hybridized nuclei displayed the same abnormal hybridization pattern for a specific probe. Of the attempted analyses, 90.2% met these criteria and were reported as informative to referring physicians within 2 d of receipt. Based on these reporting parameters, the overall detection rate for aneuploidies was 73.3% (107/146), with an accuracy of informative results for aneuploidies of 93.9% (107/114). Compared to cytogenetics, the accuracy of all informative FISH results, euploid and aneuploid, was 99.8%, and the specificity was 99.9%. In those pregnancies where fetal abnormalities had been observed by ultrasound, referring physicians requested FISH plus cytogenetics at a significantly higher rate than they requested cytogenetics alone. The current prenatal FISH protocol is not designed to detect all chromosome abnormalities and should only be utilized as an adjunctive test to cytogenetics. This experience demonstrates that FISH can provide a rapid and accurate clinical method for prenatal identification of chromosome aneuploidies.

Adult↗
PubMed1992

Successful outcome after Nd : YAG laser separation of chorioangiopagus-twins under sonoendoscopic control.

Endoscopic laser coagulation of the chorioangiopagus was successfully performed at 25 weeks' gestation in a pregnancy presenting with acute polyhydramnios due to twin transfusion syndrome. Under local anesthesia, a rigid fetoscope housed in a 2.7 mm diameter cannula was introduced transabdominally into the amniotic cavity and the communicating vessels were coagulated by Nd : YAG laser through a fiber that was passed down the side-arm of the cannula. There was rapid normalization of urine output in both fetuses and resolution of the oligo- and polyhydramnios in the donor and recipient twins, respectively. Furthermore, there was normalization in both fetal circulations, as assessed by Doppler velocimetry, and there was gradual resolution of the hydrops in the recipient. Two healthy babies were born 9 weeks after the procedure.

Journal Article↗