Enhancement of use-dependent plasticity by D-amphetamine.

In healthy individuals, motor training can elicit use-dependent plasticity. Here the authors studied six subjects in whom training alone failed to elicit this effect. Administration of a single dose of 10 mg of D-amphetamine preceding training led to use-dependent plasticity in a subgroup of these subjects. Using pharmacologic interventions to enhance the effects of motor training might help rehabilitative efforts in patients in whom training alone fails.

The soft tissue/cartilage relationship in the laryngeal glottis.

A study of 93 larynges obtained at autopsy was made with regard to the proportion of cartilage and soft tissue in the glottis. The relevant measurements showed that the cartilage formed 48 per cent of the glottic opening and soft tissue (vibrating portion of the vocal cord) formed 52 per cent. The importance of this relationship to the classification and origin of laryngeal cancer is discussed, as is its relation to vocal cord nodules.

Plasma cell granuloma of the larynx (case report and review of the literature).

A case is reported of Plasma Cell Granuloma of the larynx treated successfully with steroids and antibiotics.

Aggressive papillary tumour of the nasopharynx followed by an aggressive papillary tumour of the middle ear. A multiple site tumour?

We report the case of a 72-year-old male presenting with a papillary adenocarcinoma of the middle ear. He had had a similar tumour excised from the ipsilateral nasopharynx seven years previously with no evidence of local recurrence. We conclude that this middle ear lesion possibly represents a second tumour. No record of such a case has been reported previously in the literature. We discuss presentation and management and highlight the need for close follow-up of these patients.

Focal myositis of the sternocleidomastoid muscle.

Focal myositis is an unusual inflammatory lesion of skeletal muscle. It usually affects the extremities, but can present rarely in the head and neck region. We present a case of an elderly woman with focal myositis of the sternocleidomastoid muscle and review of the previous literature on this subject.

Prospective investigation of the single-crystal sapphire endosteal dental implant in humans: ten-year results.

This study conducted a longitudinal prospective clinical study of the single-crystal sapphire (Al2O3) cylindrical screw-shaped endosteal dental implant, and attempted to establish clinical parameters to evaluate implant success or failure. Twenty-eight mandibular implants (17 patients) were placed. After six weeks' healing, 23 implants in 15 patients served as distal abutments for fixed prostheses (baseline). Implants were evaluated for bleeding index, crevicular fluid volume index, plaque accumulation index, radiographic index, mobility index, and patient comfort. Any implant failing in three of these criteria or implants removed were judged as failures. After 10 years, of the 21 baseline implants recalled (two implants were lost to recall), 17 were fully functional, for an 81% success rate. The use of qualitative and quantitative clinical evaluation parameters as utilized in this study appears to be important and useful in assessments of the clinical serviceability of dental implants. These parameters can be used in human clinical trials as well as in experimental animal studies.

Chlorination for degrading saxitoxins (paralytic shellfish poisons) in water.

Chlorination was investigated as a treatment option for degrading and thus removing saxitoxins (paralytic shellfish poisons, PSPs) produced by cyanobacteria (blue-green algae) from water. It was found to be effective with the order of ease of degradation of the saxitoxins being GTX5 (B1) approximately dcSTX > STX > GTX3 approximately C2 > C1 > GTX2. However the effectiveness of chlorine was pH dependent. Degradation as a function of pH was not linear with the degree of degradation increasing rapidly at around pH 7.5. At pH 9 > 90% removal was possible provided a residual of 0.5 mg l(-1) free chlorine was present after 30 min contact time. The more effective degradation at higher pH was unexpected as chlorine is known to be a weaker oxidant under these conditions. The more effective degradation, then, must be due to the toxins, which are ionisable molecules, being present in a form at higher pH which is more susceptible to oxidation. The feasibility of using chlorine to remove saxitoxins during water treatment will therefore depend strongly on the pH of the water being chlorinated. Degradation may be improved by pH adjustment but may not be a practical solution. Although saxitoxins were degraded in that the parent compounds were not detected by chemical analysis, there is no indication as to the nature of the degradation products. However, acute toxicity as determined by the mouse bioassay was eliminated.

Effects of cold-pressor and mental arithmetic on pupillary light reflex.

Dynamic pupillary light reflex (PLR) is a simple neurological test that can be useful for assessment of autonomic disorders. In this study, we investigated the changes in PLR induced by mental arithmetic task and cold pressor trials which are often applied in research as model systems to elicit autonomic responses. PLR was recorded before, during and after mental arithmetic and cold pressor tasks in 20 healthy adults (ten males and ten females). Stress-induced sympathetic activation was evident as shown in the increased blood pressure during both tasks. Although the pupillary constriction amplitude did not show significant changes, both constriction time and redilation time changed during the tasks. A significant gender effect was observed in cold pressor that suggested more sympathetic activation in males and faster parasympathetic activation in females in response to light stimulation under cold pressor.

Automatic segmentation of intra-treatment CT images for adaptive radiation therapy of the prostate.

We have been developing an approach for automatically quantifying organ motion for adaptive radiation therapy of the prostate. Our approach is based on deformable image registration, which makes it possible to establish a correspondence between points in images taken on different days. This correspondence can be used to study organ motion and to accumulate inter-fraction dose. In prostate images, however, the presence of bowel gas can cause significant correspondence errors. To account for this problem, we have developed a novel method that combines large deformation image registration with a bowel gas segmentation and deflation algorithm. In this paper, we describe our approach and present a study of its accuracy for adaptive radiation therapy of the prostate. All experiments are carried out on 3-dimensional CT images.

Post-amputation pneumatic walking aid.

A pneumatic walking training aid is described that has been developed by the Biomechanical Research and Development Unit, Roehampton, from the original design by Little. The new design has been used in the management of 87 amputations, including 44 patients over the age of 70. Ninety-four per cent of these patients were rehabilitated to walking independently on a pylon or prosthesis.

The management of unilateral vocal cord palsy by augmentation using autologous fat.

Augmentation of the vocal cord with Teflon paste has been one of the mainstays of treatment of a unilateral vocal cord palsy. Recently the licence for Teflon in the UK has been withdrawn, creating the need for an alternative. Over the last 2 years we have been using autologous fat harvested from the abdominal wall for this purpose. Fat is more difficult to work with than Teflon and we have developed a modified injection gun in order to facilitate the injection of the fat. The technique has been used in 14 patients with improvement of the voice in eight.

Mechanisms of use-dependent plasticity in the human motor cortex.

Practicing movements results in improvement in performance and in plasticity of the motor cortex. To identify the underlying mechanisms, we studied use-dependent plasticity in human subjects premedicated with drugs that influence synaptic plasticity. Use-dependent plasticity was reduced substantially by dextromethorphan (an N-methyl-d-aspartate receptor blocker) and by lorazepam [a gamma-aminobutyric acid (GABA) type A receptor-positive allosteric modulator]. These results identify N-methyl-d-aspartate receptor activation and GABAergic inhibition as mechanisms operating in use-dependent plasticity in intact human motor cortex and point to similarities in the mechanisms underlying this form of plasticity and long-term potentiation.

Extraction and purification of the zwitterions cylindrospermopsin and deoxycylindrospermopsin from Cylindrospermopsis raciborskii.

The hepatotoxin cylindrospermopsin (CYN) has been isolated from the cyanobacterium Cylindrospermopsis raciborskii (C. raci.). Efforts to study this toxin have been hampered by the time-consuming requirement to extract it from cultures of the organism. It is usually extracted from lyophilized cells collected from a laboratory culture. Our preliminary work suggested far more of the toxin is available in solution in the culture media than in the cells collected. We have therefore investigated the use of commercially available solid phase extraction sorbents to extract CYN from culture media in which C. raci. has been grown. A range of reverse phase and ion-exchange sorbents were tested across a range of pHs for their ability to retain CYN without success. Subsequently, graphitized carbon cartridges were found to retain CYN strongly. Elution with 5% formic acid in methanol allowed the CYN to be regained for final purification by HPLC. Deoxy-CYN, an analog of CYN can also be extracted using this procedure.