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Biomedical subjects

R S Taylor

Publications and source records attributed to R S Taylor.

At least 91 records · Page 5Linked to original sources
PubMed1996

Antiviral activities of medicinal plants of southern Nepal.

In a screening of plants used traditionally in Nepal to treat diseases that could be caused by viruses, twenty-one methanol extracts from twenty species were quantitatively assayed for activity against three mammalian viruses: herpes simplex virus, Sindbis virus and poliovirus. Assays were performed in ultraviolet (UV)-A or visible light, as well as dark, and cytotoxicity was also noted. Impressive antiviral activities were exhibited by species of Bauhinia (Fabaceae), Carissa (Apocynaceae), Milletia (Fabaceae), Mallotus (Fabaceae), Rumex (Polygonaceae), Streblus (Moraceae), Terminalia (Combretaceae) and Tridax (Asteraceae). The Carissa extract was the most active, showing activity against all three viruses at a concentration of 12 micrograms/ml. Many of the other extracts showed partial inactivation of one or more test viruses.

Animals↗
PubMed1996

UVB radiation interrupts cytokine-mediated support of an epidermal-derived dendritic cell line (XS52) by a dual mechanism.

We have established long-term dendritic cell lines from the epidermis of newborn mice. These cell lines (XS series) proliferate maximally in response to granulocyte/macrophage-colony stimulating factor, as well as to CSF-1, which is produced by skin-derived NS fibroblast lines and by keratinocytes (albeit in smaller amounts). The purpose of this study was to examine the impact of UVB radiation on CSF-1-mediated interaction of dendritic cells with fibroblasts and keratinocytes. Exposure of NS cells to UVB radiation (unfiltered FS20 sunlamp) decreased CSF-1 production at mRNA and protein levels. Both changes occurred in a dose-dependent fashion, with 50 J/m2 causing a significant reduction. UVB radiation also downregulated CSF-1 mRNA expression by Pam 212 keratinocytes. UVB exposure of XS cells diminished the surface expression of CSF-1 receptors, with 50 J/m2 causing a significant reduction. Thus, UVB radiation interrupts CSF-1-mediated cell-cell interaction by a dual mechanism: downregulating CSF-1 production and abrogating CSF-1 receptor expression. Importantly, granulocyte/macrophage-colony stimulating factor receptor expression by XS cells was also inhibited by UVB radiation, once again, with 50 J/m2 producing significant inhibition. We propose that the resulting CSF-1 deficiency in epidermal microenvironment and unresponsiveness by dendritic cells to relevant growth factors may contribute to UVB-mediated loss of resident epidermal dendritic cells (i.e., Langerhans cells) in skin.

Animals↗
PubMed1996

Detection of telomerase activity in malignant and nonmalignant skin conditions.

Telomeres are the end regions of linear chromosomes, and in normal somatic cells the lengths of telomeres shorten with successive cell divisions. Telomerase, a ribonucleoprotein enzyme, maintains the length of telomeres in immortal and germline cells. Although present in human fetal tissues, shortly after birth telomerase activity is not detectable except in germline cells, hematopoietic cells, and most human primary tumors. In the present study we show telomerase activity to be present in 73 of 77 basal cell carcinomas, 15 of 18 nonmetastatic cutaneous squamous cell carcinomas, and 6 of 7 cutaneous melanomas, contrasting with extremely low levels detected in sun-protected skin. Sun-damaged skin, psoriatic lesional skin, and skin from lesions of poison ivy dermatitis, however, have increased levels of telomerase activity compared to sun-protected skin, although less than that detected in tumor tissue. Because telomerase activity can be found in inflammatory lesions of the skin, this indicates that telomerase activity does not always correlate with the malignant phenotype. In addition, we show that telomerase activity is localized to the epidermis of newborn foreskin, which suggests that telomerase is expressed constitutively by cells in the epidermis. Finding higher levels of telomerase activity in sun-exposed skin compared to nonexposed skin suggests that environmental factors may modulate telomerase activity.

Adult↗
PubMed1995

Keyhole surgery.

Explore the source record for details and available documents.

Herniorrhaphy↗
PubMed1995

Colony-stimulating factor-1 secreted by fibroblasts promotes the growth of dendritic cell lines (XS series) derived from murine epidermis.

We have established recently from mouse epidermis long-term dendritic cell lines (XS series) that resemble epidermal Langerhans cells (LC) by their surface phenotype, Ag-presenting profile and cytokine mRNA profile. The growth of XS lines was promoted maximally by granulocyte-macrophage-CSF or by a factor secreted by NS lines, which are fibroblastic cell lines established from dispase-separated specimens of mouse epidermis. The purpose of this study was to determine the identity of XS cell growth factor secreted by NS cells. We report the following: 1) NS cells express constitutively mRNA for CSF-1; 2) XS cells express the CSF-1R at mRNA and protein levels; 3) rCSF-1 mimics NS culture supernatant in its ability to promote XS cell growth; 4) NS supernatant-dependent XS cell growth is blocked completely by each of two Abs against the CSF-1R. We conclude that CSF-1 is responsible for the XS growth-promoting activity secreted by NS lines. We also report the following: 5) LC freshly isolated from skin express CSF-1R mRNA; and 6) fibroblasts derived from specimens of dermis also express mRNA and secrete large amounts (50-100 ng/ml) of CSF-1. These observations give rise to a new concept that dermal fibroblasts may support the survival and growth of LC (and their precursors) through the paracrine effect of elaborated CSF-1.

Animals↗
PubMed1995

Clinical outcome and restenosis following percutaneous transluminal angioplasty for ischaemic rest pain or ulceration.

The role of percutaneous transluminal angioplasty in the management of severe leg ischaemia is controversial. To investigate further the efficacy of angioplasty and the clinical consequences of restenosis, a randomly selected cohort of 29 patients with ischaemic rest pain or ulceration was studied for 6 months after a technically successful balloon angioplasty. All patients had digital subtraction arteriography at the end of follow-up. Seven of 15 patients undergoing the procedure for rest pain had sustained relief from the initial dilatation. Partial or complete healing was noted in all 14 patients with ulceration and was maintained at 6 months in 11 despite significant (greater than 30 per cent) restenosis at the angioplasty site in eight. There were no complications or clinical deterioration associated with the procedure. Angioplasty is an effective method for treating the severely ischaemic leg, especially when used to achieve ulcer healing; restenosis is often clinically unimportant.

Aged↗
PubMed1995

Screening of selected medicinal plants of Nepal for antimicrobial activities.

In an ethnopharmacological screening of selected medicinal plants used in Nepal, methanol extracts from 21 plant species were assayed for activity against 8 strains of bacteria and 5 strains of fungi. Duplicate assays were conducted with and without exposure to UV-A radiation to test for light-activated or light-enhanced activity. All 21 of the extracts showed activity against at least 2 bacterial strains, and 20 showed activity against at least 2 fungi. Six extracts were active only when exposed to UV-A light, and the antibiotic or antifungal effect of 14 extracts was enhanced upon exposure to light.

Anti-Bacterial Agents↗
PubMed1995

Osteoporotic stress fractures in anorexia nervosa: etiology, diagnosis, and review of four cases.

Anorexia nervosa (AN) is a chronic eating disorder characterized by self-imposed semi-starvation that affects 1% of adolescent females. AN predisposes to osteoporosis through hypothalamic dysfunction, which may lead to elevated cortisol as well as diminished estrogen and progesterone. The osteoporosis associated with AN affects both trabecular and cortical bone and increases the risk of osseous fracture. Fractures in this population may go unrecognized, because planar X-rays may be nondiagnostic for 6 weeks or more. Four women with AN ranging in ages from 22 to 34 with skeletal pain and nondiagnostic roentgenographs are described. Stress fractures in these patients were subsequently identified by bone scan. Although moderate exercise in patients with AN-associated osteoporosis may be beneficial, strenuous exercise can be detrimental, with its potential risk of stress fractures and exacerbation of the underlying neurohormonal abnormalities. This risk for fracture may persist well after improvement in the patient's AN.

Adult↗
PubMed1994

Reliability of ankle:brachial pressure index measurement by junior doctors.

Ankle:brachial pressure index (ABPI) measurements are often performed by junior medical staff with little experience of the technique. The accuracy of such measurements is unknown. Two newly qualified doctors with no training in the use of Doppler ultrasonographic flowmeters performed ABPI measurement in 38 limbs (experiment 1). Two other newly qualified doctors then underwent a formal training session before, as well as continuous instruction during, ABPI measurements in 23 limbs (experiment 2). The doctors' measurements were compared with those obtained by experienced vascular technicians. The mean difference in ABPI measurement between the doctors and technicians in experiment 1 was greater than that in experiment 2 at both the dorsalis pedis (P < 0.05) and posterior tibial arteries. Nearly 30 per cent of the doctors' ABPI measurements in experiment 1 differed from those of the technicians by more than 0.15, in comparison with only 15 per cent of the measurements performed in experiment 2. Junior doctors should undergo formal training before performing ABPI measurements.

Aged↗
PubMed1994

Hypercoagulable states in patients with leg ischaemia.

Hypercoagulable states are found in up to 10 per cent of patients with a history of unexplained venous thrombosis. To investigate the prevalence in arterial thrombosis, thrombophilia screening was performed on 124 patients who had previously undergone lower-limb revascularization, 45 claudicants and 27 controls. Of the patients who had undergone revascularization 40 per cent had a hypercoagulation abnormality (low levels of protein C, protein S and antithrombin III or presence of the lupus anticoagulant) in comparison with 27 per cent of claudicants and 11 per cent of controls (P < 0.01). Furthermore, patients who had suffered reocclusion after revascularization were significantly more likely to have a hypercoagulation abnormality than those who had not (P < 0.05), even if the occlusion had occurred more than 6 months previously. Lupus anticoagulant was the abnormality most frequently detected and, like low protein C levels, was found only in patients with peripheral vascular disease. It appears that hypercoagulable states are common in patients with arterial disease and may predispose to failure of revascularization.

Aged↗
PubMed1994

Occult radiographic fractures of the chest wall identified by nuclear scan imaging: report of seven cases.

Between 1985 and 1990 the enactment of state mandatory seat belt laws has reduced the risk of death from auto accident by at least 40% and the risk of moderate to severe injury by 45%. Although head and facial trauma has also been significantly reduced, there has not been a decrease in injuries to other parts of the body. We evaluated seven restrained drivers who complained of persistent anterior and/or lateral chest wall pain after being in motor vehicle accidents. All had normal x-rays of the osseous thorax. Nuclear scan imaging subsequently revealed that all seven had a healing fracture of either the sternum or ribs. In each instance, direct trauma to the sternum and ribs anteriorly by the chest strap itself and/or laterally displaced bending forces transmitted to the postero lateral rib margins was sufficient to produce x-ray occult fractures.

Accidents, Traffic↗
PubMed1994

Twenty-four hour ambulatory blood pressure and heart rate in a patient with a predominantly adrenaline secreting phaeochromocytoma.

In this report, we present the symptoms, biochemical investigations, 24 hour ambulatory blood pressure and heart rate recordings in a patient before and following removal of a predominantly adrenaline-secreting phaeochromocytoma. The symptoms were of episodic shaking, faintness, nausea, palpitations, sweating and panic, chest and neck pain with headache, and are consistent with previous reports. Ambulatory blood pressure recording demonstrated that mean daily blood pressure was normal, with normal diurnal variation, and two episodes of severe hypertension and bradycardia coincident with symptoms (MAP 150 mmHg and HR 49 beats/minute, MAP 178 mmHg and HR 29 beats/minute, respectively), not reported in predominantly adrenaline-secreting phaeochromocytoma.

Adrenal Gland Neoplasms↗