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Biomedical subjects

H Moseley

Publications and source records attributed to H Moseley.

At least 37 records · Page 2Linked to original sources
PubMed2001

New sunscreens confer improved protection for photosensitive patients in the blue light region.

BACKGROUND: Some patients with photosensitivity disorders are sensitive to visible radiation. As current commercial sunscreens do not significantly absorb in this region, there is a lack of effective topical photoprotection. To meet this need a new range of sunscreens has been developed incorporating zinc oxide and pigmentary grade titanium dioxide as active ingredients. OBJECTIVES: To determine the effectiveness of the new sunscreens in providing protection for patients with visible radiation photosensitivity. METHODS: In the first part of this study, an in vitro transmission spectrum was obtained. The properties of the new sunscreens, as well as a range of commercial agents, were compared, and a new parameter, photosensitivity protection factor (PPF), was developed. This was used to predict the likely degree of protection the various sunscreens would provide for patients with photosensitivity extending into the visible region. In the second in vivo part of the study, patients with known visible (blue) light photosensitivity were tested using light at 430 +/- 30 nm and the protection factor (PF) at this wavelength was determined. RESULTS: Mean +/- SD PPFs for the new sunscreens were between 5.4 +/- 0.3 and 9.6 +/- 0.3, compared with 4.1 +/- 0.1 for Sun E45 (sun protection factor, SPF 25) and 4.2 +/- 0.1 for RoC Total (SPF 25). The derived in vivo PF for Sun E45 ranged between 1 and 4 (median 2). For the new sunscreens the range was 3 to > 10 (median 8). CONCLUSIONS: This study demonstrates that the new sunscreens do provide protection for patients with sensitivity to visible light (blue light region).

Adult↗
PubMed2001

The application of a compact multispectral imaging system with integrated excitation source to in vivo monitoring of fluorescence during topical photodynamic therapy of superficial skin cancers.

A novel, compact and low-cost multispectral fluorescence imaging system with an integrated excitation light source is described. Data are presented demonstrating the application of this method to in vivo monitoring of fluorescence before, during and after topical 5-aminolevulinic acid photodynamic therapy of superficial skin cancers. The excitation source comprised a fluorescent tube with the phosphor selected to emit broadband violet light centered at 394 nm. The camera system simultaneously captured spectrally specific images of the fluorescence of the photosensitizer, protoporphyrin IX, the illumination profile and the skin autofluorescence. Real-time processing enabled images to be manipulated to create a composite image of high contrast. The application and validation of this method will allow further detailed studies of the characteristics and time-course of protoporphyrin IX fluorescence, during topical photodynamic therapy in human skin in vivo.

Aminolevulinic Acid↗
PubMed1999

Home phototherapy: report on a workshop of the British Photodermatology Group, December 1996.

Phototherapy is a popular and effective treatment for many patients with skin diseases. However, repeated journeys to hospital for phototherapy can be inconvenient and expensive. If it were available, many patients might prefer home-based phototherapy as long as it was safe and effective. Indeed, many psoriasis patients already self-treat with ultraviolet A sunbeds at home. This report represents a consensus view from a British Photodermatology Group workshop held in December 1996, the purpose of which was to examine the potential role of home-based phototherapy in dermatological practice. We conclude that home-based therapy represents a suboptimal treatment with greater attendant risks than phototherapy in a hospital environment. The level of medical supervision of the home treatment is crucial to its safety and effectiveness. Until further studies are forthcoming, home phototherapy should be largely restricted to those with overwhelming difficulties in attending hospital.

Home Care Services↗
PubMed1998

Total radiated power, infrared output, and heat generation by cold light sources at the distal end of endoscopes and fiber optic bundle of light cables.

BACKGROUND: Skin burns and ignition of drapes have been reported with the use of cold light sources. The aim of the study was to document the temperature generated by cold light sources and to correlate this with the total radiated power and infrared output. METHODS: The temperature, total radiated power, and infrared output were measured as a function of time at the end of the endoscope (which is inserted into the operative field) and the end of the fiber optic bundle of the light cable (which connects the cable to the light port of the endoscope) using halogen and xenon light sources. RESULTS: The highest temperature recorded at the end of the endoscope was 95 degrees C. The temperature measured at the optical fiber location of the endoscope was higher than at its lens surface (p < 0.0001). At the end of the fiber optic bundle of light cables, the temperature reached 225 degrees C within 15 s. The temperature recorded at the optical fiber location of all endoscopes and light cables studied rose significantly over a period of 10 min to reach its maximum (p <0.0001) and then leveled off for the duration of the study (30 min). The infrared output accounted only for 10% of the total radiated power. CONCLUSIONS: High temperatures are reached by 10 min at the end of fiber optic bundle of light cables and endoscopes with both halogen and xenon light sources. This heat generation is largely due to the radiated power in the visible light spectrum.

Cold Temperature↗
PubMed1998

Evaluation of an optical instrument for objective assessment of oral mucosal erythema.

This study evaluated the sensitivity and reproducibility of an optical instrument, the Erythema Meter, for quantifying erythema of palatal mucosa. The instrument is based on the principle that haemoglobin in the vasculature selectively absorbs green light but has little effect on red light and allows derivation of an 'erythema index'. Non-clinical investigations were carried out by taking a series of Erythema Meter readings from each colour block on a red check-standard used by graphic artists for colour reproduction. For clinical assessment, 20 dentate patients with healthy palatal mucosa and 40 complete denture wearers (20 with denture stomatitis and 20 with healthy palatal mucosa) were enrolled, and palatal erythema determined both visually and using the Erythema Meter. Two weeks later the Erythema Meter readings for the 40 patients with healthy palatal mucosa were repeated, to allow assessment of the reproducibility of the Erythema Meter scores. The median erythema index was 12 (range 2-38) for dentate patients with healthy palatal mucosa and 5 (range 0-29) for denture wearers with healthy palatal mucosa. For denture stomatitis patients the median erythema index was 95 (range 36-117). The overall reproducibility coefficient was 88%. Visual scoring correlated poorly with the Erythema Meter scores for those with moderate degrees of erythema. The Erythema Meter provides an objective and reproducible means of measuring the degree of erythema of the palatal mucosa.

Adolescent↗
PubMed1998

A hazard assessment of artificial tanning units.

As a result of increasing concern over the use of artificial tanning units, many local government recreation departments are phasing out the use of sunbeds on their premises, resulting in some clients switching to high street parlours about which little is known. An Environmental Health survey was conducted in all 32 tanning premises within a local government area (Perth & Kinross, Scotland). A number of significant problems emerged in the private sector. In this group, there was no form of cumulative UV exposure control in 89% of premises and 81% failed to give adequate advice and information to customers. We conducted UV spectral irradiation measurements in 38 tanning units using a double grating spectroradiometer. When a carcinogenic weighting factor was applied to these measurements, it was found that a 10 min exposure in a high intensity stand-up cabinet carried the same carcinogenic risk as approximately 30 min of local (56 degrees North) mid-day summer sunlight or 10 min of Mediterranean sunlight at mid-day. A questionnaire completed by 57 customers revealed a wide pattern of usage; 6 (10%) had more than 20 h exposure in the previous 12 months and 3 (5%) had made regular use of sunbeds for the previous 16 to 20 years. These results indicate that there is a need for continuing public education and surveillance of commercial artificial tanning units.

Beauty Culture↗
PubMed1997

Ultraviolet B radiation was increased at ground level in scotland during a period of ozone depletion.

The potentially harmful effects associated with stratospheric ozone depletion are widely acknowledged. As the ozone layer principally absorbs ultraviolet (UV) radiation of wavelengths below 290 nm, reductions in stratospheric ozone levels are likely to result in increased UVB at the earth's surface, with the risk of increased incidence of skin cancer. Measuring the sun's spectrum at ground level requires sophisticated and reliable spectral instruments. Results are reported for this for the first time in the U.K. using spectral instruments, showing a significant increase in short wavelength UV radiation at a time of depleted stratospheric ozone. If this trend increases, future ozone depletion could contribute to known risks for cutaneous malignancies of all types.

Atmosphere↗
PubMed1996

Comparison of photodynamic therapy with cryotherapy in the treatment of Bowen's disease.

The efficacy and suitability of photodynamic therapy (PDT) was compared with that of cryotherapy in the treatment of 40 lesions of Bowen's disease. Lesions were randomized to receive either cryotherapy with liquid nitrogen, or PDT using a portable desktop lamp incorporating a 300 W xenon short arc discharge source. A porphyrin precursor, 5-aminolaevulinic acid (5-ALA), was applied topically 4 h before irradiation in the PDT group. Each lesion received 125 J/cm2 at a fluence rate of 70 mW/cm2. All patients were reviewed at 2-monthly intervals and treatments repeated if required. Cryotherapy produced clearance in 10 of 20 lesions after one treatment, the remaining 10 lesions requiring two or three treatment applications. PDT resulted in clearance of 15 of 20 lesions after one treatment and of the remaining five lesions after a second treatment. The probability that a lesion cleared after one treatment was greater with PDT than cryotherapy (P < 0.01). Cryotherapy was associated with ulceration (five of 20), infection (two of 20) and recurrent disease (two of 20); no such complications occurred following PDT. PDT using a non-laser light source and topical 5-ALA appears to be at least as effective as cryotherapy in the treatment of Bowen's disease with fewer adverse effects.

Aged↗
PubMed1995

A clinical study of pulsed Nd: YAG laser-induced pulpal analgesia.

The pulsed Nd: YAG laser is advocated as an alternative means of providing analgesia during routine dental procedures. Since the evidence to support this claim is mainly anecdotal, a clinical trial was carried out using an electric pulp tester (EPT) to measure the extent and duration of any analgesic effect induced by pulsed Nd: YAG laser treatment. A double-blind crossover experiment involving laser and sham treatments was used on 21 subjects. A small (3.6 arbitrary units) but statistically significant increase was observed in the mean responses measured 5 min after laser treatment with 113 mJ pulses at 15 pulses s-1 (pps) for 3 min. The pain thresholds returned to baseline values after 60 min. No statistically significant changes in threshold were found with the sham treatment. The order in which laser and sham treatment was received made no difference to the results.

Adult↗
PubMed1995

Quantitative assessment of the blue-light hazard during indirect ophthalmoscopy and the increase in the "safe" operating period achieved using a yellow lens.

PURPOSE: The indirect ophthalmoscope presents a blue-light hazard with the potential for causing photochemical injury to the retina. In this study, this hazard was assessed with respect to the threshold limit values (TLVs) recently adopted by the American Conference of Governmental Industrial Hygienists. METHOD: Spectral radiometric measurements were made from a standard indirect ophthalmoscope headset used in conjunction with either a clear or a yellow lens. The results were weighted spectrally with the published blue-light hazard function. RESULTS: When the clear lens was used, the TLV was exceeded after approximately 2.5 minutes. The yellow lens filtered out the more hazardous blue wavelengths of light and this increased the "safe" operating period by a factor of approximately 20. CONCLUSION: In clinical practice, with a clear lens, the TLV could be exceeded easily if the patient is subjected to prolonged or repeated examination because the blue-light hazard is additive in a linear manner for periods as long as 3 hours with a potential for a cumulative effect over longer periods. Furthermore, some ophthalmic patients, such as those with aphakia, are less tolerant of blue-light than healthy subjects. In the interests of patient safety, it is recommended that yellow lenses are considered for use for routine indirect ophthalmoscopy.

Equipment Safety↗
PubMed1995

The effect of an Nd-YAG pulsed laser on the cleaning of the root canal and the formation of a fused apical plug.

A Neodymium-yttrium aluminium garnet (Nd-YAG) pulsed laser was used in vitro to determine whether various laser energy levels from 0.75 W to 1.7 W at 15 pulses s(-1) (pps) were able to (i) remove debris from the walls of prepared root canals (ii) remove pulpal tissue from unprepared canals and (iii) create a fused apical plug from dentine chips, hydroxyapatite (HAP) or low-fusing dental porcelain. Single-rooted teeth were sectioned at the amelocemental junction and the crowns discarded. The root canals of 50 teeth were prepared chemomechanically and allocated to four groups of 10 teeth for laser treatment. One group was left unlased as a control. After lasing, the teeth were split longitudinally, stained and examined for residual debris. Results showed that there was no statistically significant difference between the groups (P<0.05). A further 20 teeth were not prepared and lased in the coronal one-third of the root canal at different energy levels; five teeth were not lased. The teeth were split and examined as previously. The results showed that lasing cleaned the coronal part of the root canal almost completely of pulpal tissue. In the final part of the study laser energy was applied to dentine chips, HAP and low-fusing porcelain in an attempt to produce a fused apical plug. The laser was unable to melt the dentine chips but some hardening of HAP occurred when combined with blue food-colouring, with or without glycerine, at energy levels of 1.0 W, at 15 pps for 30 s. Superficial hardening of low-fusing porcelain occurred at 1.0 W, 15 pps for 30 s.

Bicuspid↗
PubMed1994

Blue light curing units--a dermatological hazard?

The setting reactions of a large number of dental materials are activated upon exposure to visible blue light emitted from a curing unit. Although the wavelength (lambda) from such devices is principally in the visible spectrum (lambda > 400 nm) a small amount of ultraviolet radiation (UV) is also present. Little attention has been paid to the consequences of such exposure upon the skin of dental surgeons' fingers. This investigation studied the level of UVA I (lambda = 340-400 nm) emitted by three commonly used polymerisation sources and assessed the level of protection afforded by six brands of surgical glove. The integrated irradiances of the Translux, Topaz T100 and Heliomat units in the UVA I range were 15861, 3611 and 305 mW/m2 respectively. For all gloves the mean % transmission, at lambda = 400 nm, was less than 4% with the exception of one brand where, in the stretched state, the level of transmission was 7%. It is concluded that the risk of initiating adverse dermatological consequences as a result of exposure to UVA I, emitted by light polymerisation units, is minimal in normal usage. The combined effects of exposure to radiation of this type and contamination of the fingers with quantities of irritant chemicals, such as found in many dental materials, are unknown. Due to the ability of the gloves to shield the skin from both chemicals and UVA I it is recommended that gloves are routinely worn for all light curing procedures.

Dental Equipment↗
PubMed1994

Ultraviolet and laser radiation safety.

Both ultraviolet radiation and laser radiation occupy pmt of the Spectrum designated "optical radiation". Thus, measurement techniques are similar and the same organs (eyes and skin) are at risk from accidental exposure. However, the equipment used to produce ultraviolet and laser radiation differs substantially and the harm caused by each type of radiation is also different. Another significant difference arises from the fact that ultraviolet radiation is natural with associated general population exposure. Consequently, the present article reviews the current status of both ultraviolet and laser radiation with the material divided into two sections where each hazard is considered separately.

Animals↗
PubMed1994

Dehydration: a model for (low-temperature) argon laser tissue bonding.

Despite considerable investigation, the mechanism of laser assisted vascular anastomosis remains unknown. Indications suggest that bonding is the result of thermal action, particularly the thermal denaturation of tissue proteins. However, our own work has led us to conclude that dehydration is an important factor. Hence, we have proposed that laser anastomosis is the result of dehydration at the apposed tissue faces, induced by laser irradiation. This was investigated by comparing the properties of bonds created by dehydration with those created by laser. The bonds were created using parameters consistent with laser anastomoses created in vivo. Results revealed that anastomoses created by dehydration were equivalent to those created by laser, with little difference in strength, histology or response to rehydration. The only significant difference (p < 0.02) was mean bond strength created at temperatures above the denaturation temperature of the tissue (548 g cm(-2) by laser, 994 g cm(-2) by dehydration). Given the similarity of bonds created by the two methods, we conclude that the same mechanism (i.e. dehydration) is likely to be responsible for bonding in both cases and therefore that argon laser bonding is mediated by dehydration.

Anastomosis, Surgical↗
PubMed1993

The suitability of SunCheck patches and Tanscan cards for monitoring the sunburning effectiveness of sunlight.

UV-sensitive products which undergo a colour change on exposure to UV radiation are available for use by the general public. We have evaluated SunCheck patches of various sensitivities, and Tanscan UV sensor cards, in terms of their temperature stability, wavelength response and response to sunlight. The products exhibited no perceptible colour change when the temperature was maintained at 45 degrees C for 4 hours; on exposure to monochromatic radiation, the sensitivity peaked at a wavelength of 335 and 355 nm for SunCheck and Tanscan, respectively; the response to sunlight under clear conditions was reasonably consistent, with the coefficient of variation for each type of material ranging between 12.5 and 27%. These products are based on the incorrect concept that there is a 'safe' dose of UV radiation. Thus, they cannot be recommended to the public as a reliable way of reducing the risk of skin cancer.

Dermatology↗