National reference doses for dental cephalometric radiography.

OBJECTIVES: Diagnostic reference levels (DRLs) are an important tool in the optimisation of clinical radiography. Although national DRLs are provided for many diagnostic procedures including dental intra-oral radiography, there are currently no national DRLs set for cephalometric radiography. In the absence of formal national DRLs, the Health Protection Agency (HPA) has previously published National Reference Doses (NRDs) covering a wide range of diagnostic X-ray examinations. The aim of this study was to determine provisional NRDs for cephalometric radiography. METHODS: Measurements made by the Dental X-ray Protection Service (DXPS) of the HPA, as part of the cephalometric X-ray equipment testing service provided to dentists and dental trade companies throughout the UK, were used to derive provisional NRDs. RESULTS: Dose-area product measurements were made on 42 X-ray sets. Third quartile dose-area product values for adult and child lateral cephalometric radiography were found to be 41 mGy cm² and 25 mGy cm², respectively, with individual measurements ranging from 3 mGy cm² to 108 mGy cm². CONCLUSION: This report proposes provisional NRDs of 40 mGy cm² and 25 mGy cm² for adult and child lateral cephalometric radiographs, respectively; these doses could be considered by employers when establishing their local DRLs.

Determining exchange splitting in a magnetic semiconductor by spin-filter tunneling.

A large exchange splitting of the conduction band in ultrathin films of the ferromagnetic semiconductor EuO was determined quantitatively, by using EuO as a tunnel barrier and fitting the current-voltage characteristics and temperature dependence to tunneling theory. This exchange splitting leads to different tunnel barrier heights for spin-up and spin-down electrons and is large enough to produce a near-fully spin-polarized current. Moreover, the magnetic properties of these ultrathin films (<6 nm) show a reduction in Curie temperature with decreasing thickness, in agreement with theoretical calculation [R. Schiller, Phys. Rev. Lett. 86, 3847 (2001)10.1103/Phys. Rev. Lett.86.3847].

Chronic UVB exposure enhances in vitro percutaneous penetration of 5-aminulevulinic acid in hairless mouse skin.

BACKGROUND AND OBJECTIVES: (Pre)cancerous skin lesions accumulate more protoporphyrin IX (PpIX) upon topical application of 5-aminolevulinic acid (ALA) than the surrounding normal skin. This might be the result of a higher percutaneous penetration of ALA into (pre)cancerous skin. STUDY DESIGN/MATERIALS AND METHODS: ALA penetration through (1) healthy skin with intact stratum corneum, (2) healthy skin with reduced stratum corneum (i.e. tape stripped skin) and (3) diseased skin with dysplastic and thickened epidermis (chronically UVB-exposed skin) was determined in an in vitro model with hairless mouse skin. RESULTS: More ALA had penetrated through chronically UVB-exposed skin than through normal non-exposed skin after 8 hours ALA application. The amount of ALA penetrated through chronically UVB-exposed skin was smaller than through tape stripped skin. CONCLUSIONS: The stratum corneum barrier function is less effective in chronically UVB-exposed skin than in normal non-exposed skin, but more effective than in tape stripped skin. A higher penetration rate of ALA into (pre)cancerous lesions may be (partly) responsible for the greater accumulation of PpIX in such lesions.

Comparative in vitro percutaneous penetration of 5-aminolevulinic acid and two of its esters through excised hairless mouse skin.

BACKGROUND AND OBJECTIVES: ALA esters have been developed to improve PpIX production in ALA-PDT, but they do not perform as well in skin as they do in cells and the bladder. STUDY DESIGN/MATERIALS AND METHODS: The in vitro penetration across normal mouse skin of ALA and its methyl and hexyl ester was determined for different application concentrations. ALA and the esters were also applied to tape stripped skin to determine the effect of the stratum corneum. RESULTS: The penetration of ALA and the esters was higher through tape stripped skin than through normal skin (P < 0.01), showing that the stratum corneum is an important barrier. The experiments with different application concentrations indicated that the skin penetration through normal skin and tape stripped skin is highest for ALA and lowest for the hexyl ester. CONCLUSIONS: The differences in skin penetration properties could be (co-)responsible for the finding that ALA esters do not induce substantially higher PpIX levels in in vivo skin.

Effect of photodynamic therapy on recurrent pituitary adenomas: clinical phase I/II trial--an early report.

Pituitary adenomas, although histologically benign, are not always curable by surgery alone, principally because of dural infiltration, as well as their peculiar anatomical location. Radiotherapy has been employed as an adjuvant therapy to address residual disease with favourable results. This approach is, however, not without side effects, and it cannot be repeated. We are therefore investigating the effectiveness of photodynamic therapy (PDT) on recurrent pituitary adenomas in humans. This study details the protocol applied to 12 patients with recurrent pituitary adenomas, which involved systemic administration of photosensitizer (Photofrin) followed, after a period of 24-48 h, by intraoperative illumination of the tumour bed using 630 nm laser light. The primary end points were visual, endocrine and radiological improvement. The incidence of side effects was also monitored. The longest follow-up is 2 years. Most patients suffering from visual acuity or field defects have shown improvement when followed for 12 months or more. Three patients showed complete recovery of their visual fields. All those who presented with functional adenomas have shown reduction in their hormone levels. Tumour volume, relative to the preoperative size, was 122, 87, 66, 60 and 46% at 4 days, and 3, 6, 18 and 24 months, respectively. One patient developed severe skin photosensitization due to early exposure to direct sunlight and three others displayed minor skin reactions. There was no treatment-related mortality or morbidity. One patient (operated transcranially) developed hemiparesis postoperatively, which recovered completely. We think this is unrelated to the treatment. This prospective study demonstrates that PDT may be safely applied to the pituitary fossa by the trans-sphenoidal route and indicates the need for a randomized, controlled trial in order to establish its therapeutic potential.

St John's wort for depression: a systematic review.

To address whether St John's wort is useful for the treatment of depression we attempted to retrieve all English-language articles with data on the efficacy, safety, and availability of St John's wort. Randomized, controlled, double-blind trials were selected and assessed for methodological quality using a standardized checklist, and data on pharmacology, cost, regulation, and safety were extracted. Eight studies were identified, found to be of generally good methodological quality, and determined to provide a modest amount of data to suggest that St John's wort is more effective than placebo in the treatment of mild to moderate depression. The absolute increased response rate with the use of St John's wort ranged from 23% to 55% higher than with placebo, but ranged from 6% to 18% lower compared with tricyclic antidepressants. More data are required to assess both its use in severe depression and its efficacy compared with other antidepressants. Rates of side effects were low. As a dietary supplement, St John's wort is currently largely unregulated, but the Food and Drug Administration is reviewing plans to tighten its regulatory oversight.

The subcellular localization of Zn(II) phthalocyanines and their redistribution on exposure to light.

The development of second-generation photosensitizers to improve photodynamic therapy (PDT) is an area of extensive research. Three such compounds that have been synthesized in our group are polysubstituted Zn(II) phthalocyanines that differ in their overall net charge (one cationic, one anionic and one neutral). The aim of this study was to characterize the drugs in terms of their uptake, cell killing efficacy and subcellular localization in RIF-1 cells in vitro and to identify any possible structure/function relationships. The results show that the relative uptakes and cell killing efficacy of each of the drugs follows the order cationic > > neutral > anionic. For the anionic and cationic drugs the initial subcellular localization was in the lysosomes as determined by fluorescence microscopy. The neutral phthalocyanine demonstrated a more diffuse localization characteristic of membrane staining with some involvement of the Golgi apparatus in the perinuclear area. Following light exposure the drugs rapidly relocalized to different sites within the cell in a manner that was apparently charge dependent and this relocalization was accompanied by an increase in the fluorescence associated with the drugs. This indicates that the primary sites of localization of these photosensitizers may not be as important as their secondary sites in producing cell killing during PDT, especially as the fluorescence intensity increases on relocalization.

Hypnosis treatment of clinical pain: understanding why hypnosis is useful.

Clinical and experimental research literature indicates hypnosis is very useful for severe and persistent pain, yet reviews suggest hypnosis is not widely used. To encourage more widespread clinical application, the author reviews recent controlled clinical studies in which hypnosis compares favorably with other interventions; links advances in understanding endogenous pain modulation to a neurophysiologic view of hypnosis and hypnoanalgesia; relates the neurophysiology of hypnoanalgesia to management of chronic pain; challenges the view that hypnotic pain control is only for the highly hypnotizable patient; and raises issues about how people learn to control pain with hypnosis. Training in hypnotic analgesia may usefully enhance nervous system inhibitory processes that attenuate pain.

Photosensitization of the endometrium with topical 5-aminolevulinic acid.

Photosensitization of the endometrium was attempted in vitro and in vivo by intrauterine administration of 5-aminolevulinic acid, which is converted to the photosensitizer protoporphyrin IX. Protoporphyrin IX was found in both functional and basal layers of the endometrial glands at concentrations nine and 10 times higher than myometrium in in vitro and in vivo experiments, respectively. Selective endometrial photosensitization is possible with topical 5-aminolevulinic acid, but it might not be distributed sufficiently evenly for use as a sensitizing agent in photodynamic ablation.

The quantitative determination of Photofrin and Polyhaematoporphyrin in plasma: pitfalls and inaccuracies.

An accurate and relatively rapid fluorometric assay for Photofrin, or our own preparation Polyhaematoporphyrin (PHP), in plasma has been developed. This method takes into account the significant proportion of hydrolysis-resistant material now known to be present in these sensitizers, which has undoubtedly led to the inaccurate assessment of these drugs and other preparations of haematoporphyrin derivative (HPD) in numerous studies. The method was devised to allow for incomplete hydrolysis by calibration with plasma samples to which known amounts of photosensitizer were added in vitro. It was then compared with an "absolute" method in which plasma from animals that had received 14C-labelled drug was subjected to radioactivity assay. The two approaches gave almost identical results. The calibration method is applicable to the determination of any HPD-derived drug from patient or animal studies. As an example of its use in the present study, it was applied to the determination of the pharmacokinetics of PHP in the rat.

Ego receptivity and hypnotizability--two pilot studies: a brief communication.

Ego receptivity has been described as important for the psychotherapy process and as a characteristic of hypnosis (Deikman, 1974: Dosamantes-Alperson, 1979; Fromm, 1979). Receptivity also has been associated with a measure of absorption (Tellegen, 1981). In the first pilot study with 6 dance/movement therapy students, higher observer ratings of receptivity were associated with greater hypnotizability (r = .79, df = 4, p less than .05, 2-tailed test). In the second pilot study, the correlation was replicated (r = .51, df = 12, p = .06, 2-tailed test) with 14 dance/movement therapy students. In the second pilot study, receptivity did not correlate with absorption. Receptivity and absorption, however, accounted for 54% of hypnotizability population variance in a step-wise multiple regression. Receptivity accounted for a unique part of the variance after the effects of absorption were removed. It was concluded that receptivity should be explored as a potential predictor of hypnotizability, and that a reliable scaled measure of receptivity should be developed.

Guided imagery, hypnosis and recovery from head and neck cancer surgery: an exploratory study.

The value of a brief, preoperative hypnosis experience was explored with a sample of 36 head and neck cancer surgery patients. 15 patients volunteered for the experimental hypnosis intervention. 21 patients who received usual care (no hypnosis) were followed through their hospital charts and were used as a comparison group. Hypnotic intervention and usual care groups were comparable in terms of relevant demographic variables. Postoperative hospitalizations for the hypnotic intervention group were significantly shorter than for the usual care group. Within the hypnotic intervention group, hypnotizability was negatively correlated with surgical complications and there was a trend toward a negative correlation between hypnotizability and blood loss during surgery. Findings suggest that imagery-hypnosis may be prophylactic, benefitting patients by reducing the probability of postoperative complications and thereby keeping hospital stay within the expected range. Recommendations are presented for a controlled, randomized, clinical trial with a sufficiently large sample to provide the opportunity for statistical analysis with appropriate power.

The uncertain relationship between hypnotizability and smoking treatment outcome.

Literature on the relationship between hypnotizability and smoking treatment outcome was reviewed. 91 private patients treated for smoking with hypnotherapy participated in an investigation designed to correct problems in some of the earlier research. 43% quit smoking by the end of treatment but only 16% abstained at least 6 months. Neither immediate quitting nor continued abstinence correlated with hypnotizability. Other variables hypothesized to predict smoking cessation also were not correlated with outcome: number of treatment sessions, need to smoke, motivation to quit, and gender. The low abstention rate may have impeded verification of a relationship between hypnotizability and treatment outcome.

The biosynthesis of the chromophore of phycocyanin. Pathway of reduction of biliverdin to phycocyanobilin.

The later stages in the pathway of biosynthesis of phycocyanobilin, the chromophore of phycocyanin, were studied by using radiolabelled intermediates. Three possible pathways from biliverdin IX-alpha to phycocyanobilin were considered. 14C-labelled samples of key intermediates in two of the pathways, 3-vinyl-18-ethyl biliverdin IX-alpha and 3-ethyl-18-vinyl biliverdin IX-alpha, were synthesized chemically and were administered to cultures of Cyanidium caldarium that were actively synthesizing photosynthetic pigments in the light. Neither of these two compounds was apparently incorporated into the phycobiliprotein chromophore, suggesting that two of the three pathways were not operative. By elimination, the results imply that the third possible pathway, which involves phytochromobilin, the chromophore of phytochrome, represents the route for biosynthesis of phycocyanobilin. Unfortunately, since 14C-labelled phytochromobilin is not available, no direct proof of this pathway could be obtained. However, if correct, the present interpretation represents a unified pathway for biosynthesis of all plant bilins, via the intermediacy of phytochromobilin.

Counterintuitive findings on the hypnotizability of state and nonstate theorists: a brief communication.

17 research psychologists, identified as reflecting state or nonstate theoretical positions regarding hypnosis, were requested to provide anonymous information about their personal hypnosis test scores. There were no differences between the state and nonstate groups in mean scores on the Harvard Group Scale of Hypnotic Susceptibility, Form A (Shor & E. Orne, 1962) or the Stanford Hypnotic Susceptibility Scale, Form C (Weitzenhoffer & Hilgard, 1962), and no differences in the numbers who reported that they used hypnotherapy to treat patients. Small sample size suggests caution in interpretation of the present results, but it appears that commitment to a state or nonstate theory is not necessarily related to the hypnosis researcher's personal experience with hypnosis.

And so to sleep: hypnotherapy for lagophthalmos.

We used hypnosis to facilitate eye closure during sleep for a 44-year-old woman whose nocturnal lagophthalmos prevented use of a contact lens following cataract surgery and could have resulted in severe corneal damage. On three separate occasions the symptoms remitted following a very brief course of treatment. We discuss the results in terms of alternate theories of hypnotic performance.

Pushing the limits of recovery: hypnotherapy with a stroke patient.

Hypnotherapy was used to assist recovery of left arm function following stroke in a 66-year-old woman. Treatment protocol is described, and results are discussed in terms of how hypnosis may facilitate voluntary motor movement. Recent literature on cortical changes in hypnosis and motor improvement during hypnosis is discussed in relation to the present results.

A review of criterion validation research on the Questionnaire on Resources and Stress for Families with Chronically Ill or Handicapped Members.

The Questionnaire on Resources and Stress for Families with Chronically Ill or Handicapped Members (QRS) has been used as a research instrument in studies that compared parents of clinical groups with normal controls, parents of children with different clinical conditions, and pre- and postinterventions. These studies are analyzed in terms of the relationship of 15 QRS scales to child variables (e.g., age, degree of handicap); parent variables (e.g., marital status, educational level); and family variables (e.g., nationality/culture). It was concluded that the QRS fulfills four requirements for an acceptable level of validity: (1) the relationship between predictor and criterion scores is statistically significant; (2) use of the test probably results in more correct decisions than would be made by resorting to base rates alone; (3) the test possesses some utility; it would result in some gain to the user; and (4) the test provides some unique information.