Determination of the effects of blood depth in the dermis on skin colour in a novel skin phantom using digital imaging.

A phantom of human port wine stain (PWS) skin, previously described by the authors, that takes into account its light propagation and scattering properties, was used to model varying depths of blood within PWS skin. Digital images of these phantoms were then acquired under controlled conditions, and the colour information was abstracted with a digital image processing suite. These colour data were analysed quantitatively for each depth of blood, and the relationship between depth of blood and colour was defined. A linear relationship was observed between depth of blood within the phantom and hue, hue being an intuitive measure of how colour is perceived by the human eye. As PWS clearance by laser treatment is dependant, to a large degree, on vessel depth within the skin, the ability to abstract colour data from PWS or, in fact, any vascular lesion within the skin, may help predict the degree of clearance before treatment is actually instigated. In the future, the comparison of phantom colour data with data from actual digital images of affected PWS skin, combined with a knowledge of laser light penetration depths, may provide a useful adjunct to clinical judgement in the prediction of PWS treatment outcomes.

Magnetic resonance imaging in rectal cancer downstaged using neoadjuvant chemoradiation: accuracy of prediction of tumour stage and circumferential resection margin status.

OBJECTIVE: The aim was to examine the accuracy of magnetic resonance imaging (MRI) in predicting circumferential resection margin (CRM) involvement, T- and N-stage in patients with locally advanced carcinoma of the rectum, who had undergone long-course downstaging chemoradiation (CRT). METHOD: Patients with rectal cancer were selected for long-course downstaging CRT if their tumour was considered to threaten (< or = 1 mm) or involve the CRM on MRI. Eighty such patients had a repeat MRI at a median of 6 weeks post-CRT followed by surgical excision soon thereafter. The findings on the post-CRT MRI were compared with histological examination of the surgical specimen. RESULTS: For CRM involvement, post-CRT restaging MRI had an accuracy of 81% (65/80) a sensitivity of 54% (7/13), a specificity of 87% (58/67), a positive predictive value of 44% (7/16) and a negative predictive value of 91% (58/64). Accuracy for T- and N-staging was 43% (34/80) and 78% (62/80), respectively. 38% of T-stages were overstaged and 20% understaged. 4% of N-stages were overstaged and 19% understaged. The 13 patients with histological positive CRM had worse clinical outcomes than the 67 patients with negative CRM in terms of disease-free survival (relative risk of reduced DFS 4.6, P = 0.001) and overall survival (relative risk of death 3.6, P = 0.016). CONCLUSION: Magnetic resonance imaging has good specificity and negative predictive value for predicting an uninvolved CRM post downstaging CRT in locally advanced rectal cancer although sensitivity and positive predictive value for an involved CRM were unsatisfactory. The shortcomings of MRI stem from poor differentiation of viable tumour from posttreatment changes and inability to identify small nodal and tumour deposits. Clinical correlates in this group of patients have confirmed the importance of achieving a clear CRM at surgery.

Microsurgical skill acquisition in a one-day introductory course with performance evaluation using software-assisted scoring system.

BACKGROUND: Recent emphasis on microsurgical skill acquisition at an earlier stage of plastic surgery training has seen a shift toward objective competence-based assessment. Yet no objective measures of spacing or alignment exist, with few validated models that assess ability. The authors propose a novel software analysis scoring system to objectively measure spacing, alignment and the overall improvement in a 1-day, introductory course setting. METHODS: Images of standard 4-mm latex strips that had been sutured by participants using the Microtrainer system were uploaded onto calibrated, online software. Sutures were analysed with regard to spacing, alignment and density. From these measurements, a total score was calculated, one on initial assessment at the course beginning (Score 1) and another on final assessment at the course end (Score 2), thereby facilitating measurement of the overall improvement. RESULTS: A total of 38 microsurgical anastomoses from 19 participants ranging from postgraduate years 1-7 were analysed. Seventeen participants had no previous experience of microsurgery. The mean average Score 1 of participants was -2 (range -12 to +22) and Score 2 was 22 (range +12 to +32), thus showing a significant improvement in candidate ability throughout the course of the day (p < 0.0001). CONCLUSIONS: Microtrainer system software analysis provides a novel, reliable, and consistent objective assessment for surgical trainees at all stages of training, without risk to patients. It has an associated cost for the initial setup, yet is timely, repeatable and can efficiently demonstrate progress in a 1-day course setting.

Asymmetric synthesis of a fully protected ent-actinoidinic acid.

[structure: see text] The asymmetric synthesis of a fully protected ent-actinoidinic acid derivative 14 is described. As key steps, an enantioselective deprotonation of an arene tricarbonylchromium(0) complex and a diastereoselective Suzuki coupling were applied. The asymmetric centers of the amino acid function were created via stereocontrolled Strecker reactions.

Malignant involvement of the iliopsoas muscle: CT appearances.

Computed tomography has led to an increase in recognition of psoas pathology in general and malignant involvement in particular. A series of 25 cases of malignant involvement of the iliopsoas is presented. The wide spectrum of malignant tumours which can invade the psoas and the diversity of CT appearances are described. In particular, it is shown that involvement is frequently extensive, a feature which has not been previously emphasised.

Sterol mutants of Saccharomyces cerevisiae: chromatographic analyses.

The sterols accumulated by ergosterol deficient mutants of the genes erg6, erg2, erg3, and erg5 (formerly po11, po12, po13, and po15) have been analyzed by gas liquid chromatography. Together with pure sterols obtained from the mutants, they were characterized on SE-30, OV-17, and OV-225. The effects of molecular structure on the retention characteristics of a range of C28 ergostane sterols have been studied. The double mutants obtained by crossing the single mutants were also analyzed and their sterols identified where possible. The effects of the erg mutations on the control of sterol biosynthesis in yeast are discussed.

Outcome of erbium:yttrium aluminium garnet laser resurfacing treatments.

Erbium:yttrium aluminium garnet (erbium:YAG) laser treatment was used to resurface skin abnormalities in patients suffering from conditions that included epidermal naevi, tuberous sclerosis, angiofibromata, neurofibromatosis, and scarring caused by acne or other means. Patients completed self-report questionnaires before their first laser test patch session, and again approximately 4 months after one treatment, so that its success could be evaluated from the patient's perspective. Disability and distress were quantified with the University of York Health Measurement Questionnaire (HMQ). Satisfaction with appearance was measured with a specifically designed Salisbury Appearance Scale (SAS) questionnaire. Pretreatment questionnaires were completed by 108 (HMQ) and 80 (SAS) patients. Thirty-six (HMQ) and 22 (SAS) patients completed a full treatment during the study period. Some patients had a test patch only during the study period. Others decided against further treatment after the test patch. Control SAS questionnaires were completed by 29 subjects on two occasions and showed no change over time. There was a significant improvement in patient satisfaction with appearance (SAS), but there was no significant difference in the disability and distress (HMQ) after erbium:YAG resurfacing.

Construction of a novel port wine stain phantom and measurement of colour by digital imaging and reflectance spectrophotometry.

A novel skin phantom is described that is constructed with quantifiable amounts of skin pigments, as well as a light scattering medium in the form of barium sulphate suspension. The two predominant skin pigments (melanin and haemoglobin) are varied in controlled amounts within the phantoms to simulate skin colour in different situations. The phantoms were devised in order to simulate the changes in skin colour particularly after laser treatment of port wine stains, where superficial cutaneous vascularity is reduced. Preliminary investigations of two techniques for skin colour assessment were subsequently carried out so that their suitability for measuring colour in the skin phantoms could be considered. A specifically designed device was constructed to enable repeatable digital image capture of the phantoms. Further development of this skin phantom may enable comparison of techniques for skin colour assessment.

The microbial metabolism of C1 compounds. The electron-transport chain of Pseudomonas am1.

Pseudomonas AM1, Hyphomicrobium X and Pseudomonas MS all contain cytochrome a/a(3) and a b-type cytochrome able to react with CO. Pseudomonas AM1 and Hyphomicrobium X also have a CO-binding cytochrome c. The purified cytochrome c (redox potential 0.26V) of Pseudomonas AM1 was not susceptible to oxidation by molecular oxygen. CO reacted slowly with the reduced form giving a CO difference spectrum with a peak at 412nm and troughs at 420nm and 550nm. Similar results were obtained with the cytochrome c of Hyphomicrobium (aerobically grown or anaerobically grown with nitrate) and with that of Pseudomonas extorquens. The results given in the present paper are incompatible with an oxygenase or oxidase function for the soluble cytochrome c of methylotrophs. Studies with whole cells of Pseudomonas AM1 and a cytochrome c-deficient mutant have demonstrated that cytochrome b (redox potential 0.009V) is the first cytochrome in the electron-transport chain for oxidation of all substrates except methanol (and ethanol) whose oxidation does not involve this cytochrome. All substrates are usually oxidized by way of cytochrome c and cytochrome oxidase (cytochrome a/a(3)), but there is an alternative route for the reduction of cytochrome a/a(3) in the mutant lacking cytochrome c. Results of experiments on cyanide inhibition of respiration and cytochrome oxidation support the suggestion that the susceptibility of cytochrome b to oxidation by molecular oxygen (reflected in its ability to react with CO) is probably irrelevant to the normal physiology of Pseudomonas AM1.

The nutritional requirements of methicillin-dependent and -resistant strains of Pediococcus cerevisiae.

A new methicillin-dependent and -resistant substrain (called MRD) of Pediococcus cerevisiae was developed by serial passages followed by replica-plating. Other methicillin-resistant, but not -dependent, substrains were isolated after treatment of the same parent strain with a mutagen. A methicillin-independent partial revertant, still resistant to the drug, was isolated from the original methicillin-dependent and -resistant substrain (CRD) developed several years ago. The requirements of some of these strains for acetate, vitamins and amino acids were compared. All except the parent methicillin-sensitive strain required pantothenate for growth, but no other consistent differences were found. The parent, but not strain CRD, grew without lysine added to the medium, though 19 other amino acids were needed by each strain. Both of these strains fermented glucose to lactate (mainly the L-isomer) in the absence or presence of methicillin.

C.T. findings in the Hajdu-Cheney syndrome.

We describe a patient with the typical features of Hajdu-Cheney Syndrome. The previously undescribed cranial computerised tomographic (C.T.) findings in this condition are discussed. In addition we describe a possible association with bowel malrotation.

Neonatal ovarian cysts: therapeutic dilemma.

Seven cases of neonatal ovarian cysts that presented over the past seven years were studied. Complications included torsion and rupture and usually occurred in cysts more than 5 cm in diameter. Surgical removal, either oophorectomy or cystectomy, was the treatment of choice. Because even cystectomy results in loss of normal ovarian tissue, and because spontaneous regression of cysts less than 5 cm in diameter can occur, a more conservative approach is now proposed. Regular ultrasonography alone is recommended if the cysts are less than 5 cm in diameter, and aspiration of the cysts followed by regular ultrasonographs if the cysts are more than 5 cm in diameter. Operation should be reserved for recurrent cysts or for those with complications. Cysts diagnosed antenatally may be aspirated in utero if there are signs of thoracic compression.

A large soft-tissue chondroma arising from the posterior mediastinum.

A case of a large intrathoracic soft-tissue chondroma arising from the posterior mediastinum is described. The plain radiographic and computed tomography (CT) findings are correlated with the histopathology.

The increasing significance of how to learn motor skills.

The training of surgeons has traditionally been an apprenticeship. In recent times it has become increasingly difficult for trainees to acquire operative skills. The acquisition and refinement of these technical skills by the surgical trainee are central to surgical teaching. Much work has been done looking into the theories of motor skill learning, working on the assumptions that if they are understood then tests may be developed to be used as skill predictors. Two schools of thought exist as to the use of neuropsychological factors in learning fine motor skills but all agree that practice and instructional feedback are essential for the correct acquisition of these essential surgical skills. With the current climate of shortened training and new guidelines its even more important to understand skill acquisition and assist in the learning of new surgical skills.

A video-fluoroscopic study of patients treated by diverticulectomy and cricopharyngeal myotomy.

Although the short- and long-term results of surgical procedures for treatment of posterior pharyngeal diverticula are well documented, their effect on normal swallowing has not been extensively investigated. The aim of this study was to assess the changes in swallowing that occur after diverticulectomy with cricopharyngeal myotomy. Fifteen patients who underwent surgery in the previous 10 years were interviewed, examined and underwent a video-fluoroscopic barium swallow. Frame to frame analysis of the barium studies showed a multitude of abnormalities, even amongst those who were asymptomatic. Excision of a pharyngeal pouch does not appear to restore a normal swallowing mechanism.

Developmental expression and characterization of the gene encoding spore coat protein SP60 in Dictyostelium discoideum.

The complete coding sequence, upstream sequence and developmental expression of Dictyostelium discoideum AX2 spore coat protein gene SP60 is reported. The gene contains two exons, 154bp and 1121bp long, separated by a 119bp intron, and encodes a protein of 46,925 molecular weight plus a 23-amino-acid hydrophobic leader sequence. The N-terminus of the mature protein consists of four copies of a perfect hexapeptide repeat (GDWNNN). The central region is rich in cysteine residues, including four highly conserved cysteine-rich repeats with homology to 'EGF-like' repeats. The C-terminus is aspartate-rich and composed of multiple imperfect copies of a D(G/D)DYD repeat followed by several repeats of the tetrapeptide DNDW and derived sequences. A TATA box promoter motif juxtaposed to an oligo(dA) stretch lies 52bp upstream of the main transcriptional start site of the gene. Six AC-rich boxes occur in the region -327 to -556, all of which contain the consensus sequence CACAC. Two GC-rich boxes and a C-rich element (TTACCCCA) are also present upstream. Another open reading frame is positioned a short distance downstream of the SP60 gene in the opposite transcriptional orientation. Expression of the SP60 gene ceases upon disaggregation to single cells and cannot be restored by high levels of extracellular cAMP either alone or in combination with conditioned medium factors.

A developmentally regulated gene encodes the dictyostelium homolog of yeast ribosomal protein S4 and mammalian LLRep3 proteins.

We report the sequence and expression of a single-copy gene from Dictyostelium discoideum which encodes the homolog of yeast ribosomal protein S4, a protein located on the small ribosomal subunit and known to play an important role in maintaining translational fidelity. Over a highly conserved central region, the Dictyostelium protein has 78% sequence similarity to the yeast protein and 83% sequence similarity to mammalian S4 protein homologs, the LLRep3 proteins. The Dictyostelium gene encodes a polypeptide 28,717 Da in size and hence this ribosomal protein has been named rp29. The N-terminal sequence of the Dictyostelium rp29 protein is extended by 61 amino acids and 14 amino acids compared to the mammalian and yeast proteins, respectively, and the C-terminus is correspondingly 15 amino acids or 2 amino acids shorter. Although the coding region of the rp29 gene is present on a single exon, a 157bp intron interrupts the 5' untranslated region and unusually contains four direct repeats of the sequence TCAATCT. The gene is expressed maximally during vegetative growth but a second peak of expression also occurs late in development which is restricted to prestalk cells; rp29 is the first Dictyostelium ribosomal protein gene reported which shows prestalk-specific developmental expression. During each round of expression, only a single 0.9kb transcript is produced which is similar in size to the yeast S4 ribosomal protein transcript (0.8kb) but markedly smaller than the mammalian LLRep3 mRNA (1.7kb) due to a much shorter 5' untranslated region.

Expression of benzene dioxygenase from Pseudomonas putida ML2 in cis-1,2-cyclohexanediol-degrading pseudomonads.

Benzene dioxygenase (BDO; EC 1.14.12.3) from Pseudomonas putida ML2 dihydroxylates benzene to produce cis-1,2-dihydroxy-cyclohexa-3,5-diene. As well as oxidising benzene and toluene, cell-free extracts of Escherichia coli JM109 expressing recombinant BDO oxidised cyclohexene, 1-methylcyclohexene and 3-methylcyclohexene. In an attempt to construct a novel metabolic pathway for the degradation of cyclohexene (via an initial BDO-mediated dihydroxylation of cyclohexene), cis-1,2-cyclohexanediol-degrading bacteria were isolated by enrichment culture. The bedC1C2BA genes encoding BDO (under the control of the tac promoter) were sub-cloned into pLAFR5, successfully conjugated into seven of the Gram-negative cis-1,2-cyclo-hexanediol-degrading isolates and stably maintained and expressed in three of them. However, despite their ability to grow on cis-1,2-cyclohexanediol as sole carbon source, express an active BDO and oxidise cyclohexene, none of the three strains was able to grow on cyclohexene as sole carbon source. Analysis revealed that BDO oxidised cyclohexene to a mixture of two products, a monohydroxylated (2-cyclohexen-1-ol) product and a dihydroxylated (cis-1,2-cyclohexanediol) product; and failure to grow on cyclohexene was attributed to the toxicity of metabolic intermediates accumulating from the 2-cyclohexen-1-ol metabolism.