Occurrence and expression of genes encoding methyl-compound production in rumen bacteria

Background

Digestive processes in the rumen lead to the release of methyl-compounds, mainly methanol and methylamines, which are used by methyltrophic methanogens to form methane, an important agricultural greenhouse gas. Methylamines are produced from plant phosphatidylcholine degradation, by choline trimethylamine lyase, while methanol comes from demethoxylation of dietary pectins via pectin methylesterase activity. We have screened rumen metagenomic and metatranscriptomic datasets, metagenome assembled genomes, and the Hungate1000 genomes to identify organisms capable of producing methyl-compounds. We also describe the enrichment of pectin-degrading and methane-forming microbes from sheep rumen contents and the analysis of their genomes via metagenomic assembly.

Results

Screens of metagenomic data using the protein domains of choline trimethylamine lyase (CutC), and activator protein (CutD) found good matches only to Olsenella umbonata and to Caecibacter, while the Hungate1000 genomes and metagenome assembled genomes from the cattle rumen found bacteria within the phyla Actinobacteria, Firmicutes and Proteobacteria. The cutC and cutD genes clustered with genes that encode structural components of bacterial microcompartment proteins. Prevotella was the dominant genus encoding pectin methyl esterases, with smaller numbers of sequences identified from other fibre-degrading rumen bacteria. Some large pectin methyl esterases (> 2100 aa) were found to be encoded in Butyrivibrio genomes. The pectin-utilising, methane-producing consortium was composed of (i) a putative pectin-degrading bacterium (phylum Tenericutes, class Mollicutes), (ii) a galacturonate-using Sphaerochaeta sp. predicted to produce acetate, lactate, and ethanol, and (iii) a methylotrophic methanogen, Methanosphaera sp., with the ability to form methane via a primary ethanol-dependent, hydrogen-independent, methanogenesis pathway.

Conclusions

The main bacteria that produce methyl-compounds have been identified in ruminants. Their enzymatic activities can now be targeted with the aim of finding ways to reduce the supply of methyl-compound substrates to methanogens, and thereby limit methylotrophic methanogenesis in the rumen.

Identification and Phenotypic Evaluation of Microbes Isolated from Breast and Formula-fed Infants Delivered Either Vaginally or by Cesarean Section (P11-075-19)

Objectives

Many factors influence the development of the infant microbiota. Based on 16S rDNA sequencing information, the type of feeding, i.e., breast vs formula, has been shown to be the most important factor, with route of delivery having transient effects in the early postpartum period. However, few recent studies have isolated individual strains from human infants or have investigated the functional properties of the infant gut microbes. We used a 2 × 2 experimental design with the goal of determining how diet and delivery interact to shape infant microbiota composition and metabolic activity.

Methods

Fresh fecal samples were collected from 3-month-old infants who were either exclusively breast- (BF) or formula-fed (FF) and cesarean- (CD) or vaginally-delivered (VD). Samples were diluted and plated on two types of media: Gut Microbiota Medium (GMM) or MRS medium. Individual colonies were picked, purified and their 16S rRNA gene sequenced for identification. These isolates were screened for growth on various carbon substrates, including human milk oligosaccharides, prebiotics and volatile fatty acids for 24–36h. Medium supernatant was collected and metabolic profiles assessed by HPLC.

Results

More than 150 bacterial strains have been isolated and identified from infant fecal samples to date. Isolates from BF/VD fecal samples were predominantly from the phylum Actinobacteria (dominated with Bifidobacterium) followed by Firmicutes and Proteobacteria. In contrast, isolates from FF/VD or FF/CD infants were primarily from the phylum Firmicutes with only a few Actinobacterial and Proteobacterial isolates. Quantitatively, most isolates represented the genera Bifidobacterium, followed by Enterococcus, and Ruminococcus. On-going phenotypic evaluation of the isolated strains for the growth and utilization of various carbon sources and metabolic profiles will provide insight into species- and strain-specific utilization of common prebiotics in human milk and infant formula.

Conclusions

This collective data will provide novel insights on how the physiological and metabolic function of the infant gut microbiota is influenced by route of delivery and early infant nutrition.

Funding Sources

NIH R01DK107561.

Untangling the cecal microbiota of feral chickens by culturomic and metagenomic analyses

Different factors may modulate the gut microbiota of animals. In any particular environment, diet, genetic factors and human influences can shape the bacterial communities residing in the gastrointestinal tract. Metagenomic approaches have significantly expanded our knowledge on microbiota dynamics inside hosts, yet cultivation and isolation of bacterial members of these complex ecosystems may still be necessary to fully understand interactions between bacterial communities and their host. A dual approach, involving culture-independent and -dependent techniques, was used here to decipher the microbiota communities that inhabit the gastro intestinal tract of free-range, broiler and feral chickens. In silico analysis revealed the presence of a core microbiota that is typical of those animals that live in different geographical areas and that have limited contact with humans. Anthropic influences guide the metabolic potential and the presence of antibiotic resistance genes of these different bacterial communities. Culturomics attempts, based on different cultivation conditions, were applied to reconstruct in vitro the microbiota of feral chickens. A unique strain collection representing members of the four major phyla of the poultry microbiota was assembled, including bacterial strains that are not typically retrieved from the chicken gut.

SU-E-T-569: A Dosimetric Comparison of Helical Tomotherapy versus Intensity Modulated Proton for Lung Cancer

PURPOSE

To evaluate the dosimetric difference between helical tomotherapy (HT) and intensity modulated proton therapy (IMPT) treatment for lung cancer patients.

METHODS

Five patients treated by HT at University of Wisconsin Carbone Cancer Center were selected. HT plans were generated on TomoTherapy treatment planning station (TomoTherapy Inc., USA). The field widths were set to 2.5 cm for all patients in this study. The IMPT plans were generated using the same planning CT and contours with our in-house treatment planning system. Three to five field spot scanning IMPT were used to deliver uniform doses to the targets while minimizing the irradiated lung volume. The proton spots used has a Gaussian sigma of 6mm and are placed on a rectangular grid. The dose distribution of each proton spot is calculated using a pencil beam algorithm with tissue heterogeneity corrections. All the dosimetric analyses are performed using normalized total dose. Alpha/beta ratios were set to 3 for normal tissues and 10 for tumors.

RESULTS

IMPT plans showed improvement of critical structure avoidance and target dose uniformity for all patients. Reductions in mean lung doses of between 81% to 27% were observed in the IMPT plans relative to the HT. The equivalent uniform dose of the target improved from 49.2 Gy in HT plan to 60.04 Gy in IMPT for patient #2, and equivalent for other cases. The maximum doses to cord were reduced by 20.5 Gy on average using IMPT. In two patient cases, the normal tissue complication probabilities were reduced by 53% and 14% with IMPT.

CONCLUSION

IMPT provides improved dose homogeneity on the target and normal structure sparing compared with HT in the treatment of non-small cell carcinoma in lung. Significant reduction of mean lung dose was demonstrated, as well as toxicity to organs at risk adjacent to the target.

Preliminary evidence for involvement of the tumour suppressor gene CHD5 in a family with cutaneous melanoma

BACKGROUND

Cutaneous melanoma is rapidly increasing in incidence worldwide and approximately 5% of melanomas are hereditary. Deletions in chromosome 1p36 have been detected in melanoma but no candidate melanoma tumour suppressor gene has yet been found in this area. Recently, strong evidence has been reported that CHD5 is a tumour suppressor gene in this region.

OBJECTIVES

To investigate CHD5 involvement in familial melanoma.

METHODS

Peripheral blood DNA from 47 melanoma families who do not carry mutations in any of the three currently recognized melanoma genes, 398 patients with sporadic melanoma and 398 geographically matched nonmelanoma-bearing controls were studied. Linkage investigation, single nucleotide polymorphism (SNP) genotyping and mutation screening studies were carried out on the CHD5 locus.

RESULTS

The CHD5 gene was not excluded by linkage analysis in any of the families. On SNP genotyping, the CHD5 rs7513548 SNP was found to be significantly associated with sporadic melanoma (odds ratio 1·53, 95% confidence interval 1·13-2·06). The AG genotype was found in 208 cases and 169 controls (cf. 141 and 175 cases and controls, respectively, for the AA genotype). On CHD5 mutation screening, a total of 50 single-base substitutions were detected. Of these, 39 were intronic and 11 were exonic. While 32 were previously recognized variants, 18 were newly identified. Three, in exons 4, 31 and 32, led to nonsynonymous substitutions. A p.Met1576Ile substitution was identified in a mother and daughter, both with invasive cutaneous melanoma.

CONCLUSIONS

This study appears to be the first report of CHD5 variants in familial cutaneous melanoma. Such CHD5 variants could block or alter the ability of CHD5 to regulate the cell cycle pathway and to effect cellular control. As only one of the 47 families studied has this variant, it appears to be a rare event and further screening of melanoma families is required to confirm whether or not CHD5 is involved in melanoma pathogenesis.

Enhanced Butanol Production by Clostridium beijerinckii BA101 Grown in Semidefined P2 Medium Containing 6 Percent Maltodextrin or Glucose

Dramatically elevated levels of butanol and acetone resulted in higher butanol and total solvent yields for hyperamylolytic Clostridium beijerinckii BA101 relative to the NCIMB 8052 parent strain grown in semidefined P2 medium containing either 6% glucose or STAR-DRI 5 maltodextrin. C. beijerinckii BA101 consistently produced on the order of 19 g of butanol per liter in 20-liter batch fermentations. This represents a greater than 100% increase in butanol concentration by the BA101 strain compared to the parent NCIMB 8052 strain. The kinetics of butanol production over time also indicate a more rapid rate of butanol production by BA101 in semidefined P2 medium containing glucose or maltodextrin. The lower levels of butyric and acetic acids produced over the course of the fermentation carried out by BA101 are consistent with an enhanced capacity for uptake and recycling of these acids. C. beijerinckii BA101 appears to more completely utilize carbohydrate compared to the 8052 strain. Carbon balance following fermentation by C. beijerinckii 8052 and BA101 indicates that sufficient carbon is available for the twofold increase in butanol concentration observed during BA101 fermentations. C. beijerinckii BA101 also has superior solvent production capacity during continuous culture fermentation in P2 medium containing 6% glucose. Volumetric solvent yields of 0.78 and 1.74 g/liter/h for BA101 and 0.34 and 1.17 g/liter/h for NCIMB 8052 were obtained at dilution rates of 0.05 and 0.20 h(sup-1), respectively. No drift towards acid synthesis (strain degeneration) was observed for up to 200 h (d = 0.05 h(sup-1)) and 100 h (d = 0.20 h(sup-1)).

Fate and transport of zoonotic, bacterial, viral, and parasitic pathogens during swine manure treatment, storage, and land application

Members of the public are always somewhat aware of foodborne and other zoonotic pathogens; however, recent illnesses traced to produce and the emergence of pandemic H1N1 influenza virus have increased the scrutiny on all areas of food production. The Council for Agricultural Science and Technology has recently published a comprehensive review of the fate and transport of zoonotic pathogens that can be associated with swine manure. The majority of microbes in swine manure are not zoonotic, but several bacterial, viral, and parasitic pathogens have been detected. Awareness of the potential zoonotic pathogens in swine manure and how treatment, storage, and handling affect their survival and their potential to persist in the environment is critical to ensure that producers and consumers are not at risk. This review discusses the primary zoonotic pathogens associated with swine manure, including bacteria, viruses, and parasites, as well as their fate and transport. Because the ecology of microbes in swine waste is still poorly described, several recommendations for future research are made to better understand and reduce human health risks. These recommendations include examination of environmental and ecological conditions that contribute to off-farm transport and development of quantitative risk assessments.

Long-term protective effect of mature DC-LAMP+ dendritic cell accumulation in sentinel lymph nodes containing micrometastatic melanoma. An EORTC Melanoma group study

8509

Background: In a previous immunohistochemical study of dendritic cells (DCs) in sentinel lymph nodes (SLNs) draining regressing melanomas we found that the accumulation of mature DC-LAMP+ DCs in SLNs was associated with local expansion of antigen- specific memory effector cytotoxic T lymphocytes and the absence of metastasis in downstream lymph nodes. The aim of this study was to investigate the prognostic importance of the maximal density of mature DCs in SLNs using the anti-DC LAMP antibody. Methods: 458 consecutive patients with micrometastatic melanoma within SLNs and 3 yrs follow-up after SLN procedure or death within 3 yrs were eligible for analysis. Semi-quantitative evaluation of mature DCDC-LAMP+ maximum density was made as follows: the slide was examined at intermediate magnification (x100) to select the area containing the maximum number of DC-LAMP+ DCs, the number of DC-LAMP+ cells per mm2 was then determined at high magnification (x400) in 3 mm2 in high density areas. Results were reported as number of cells /mm2. The maximal density of mature DC-LAMP+ DCs was evaluated by three independent observers and categorized into three classes (<100/mm2, 100- <200/mm2, ≥200/mm2) according to previously reported cutpoints. Results: There was excellent inter-observer reproducibility for maximum density of mature DC-LAMP+ DCs scores (kappa score = 0.82). There were differences in the maximal density scores and staining intensity according to the center (P<0.001). The higher the mature DC density in the SLN the longer the duration of survival [p=0.047; hazard ratio (95% CI) = 0.70 (0.50–1.00)]. Conclusions: This study is the first to report the prognostic value of DC-LAMP+ DC counts in SLNs containing metastatic melanoma. Patients with a high density of mature DCs (≥200/mm2) have the lowest risk of death. It also provides evidence that a lack of DC maturation in the SLNs is important in biological facilitation of melanoma progression.

No significant financial relationships to disclose.

Diagnostic and neural analysis of skin cancer (DANAOS). A multicentre study for collection and computer-aided analysis of data from pigmented skin lesions using digital dermoscopy

BACKGROUND

Early detection of melanomas by means of diverse screening campaigns is an important step towards a reduction in mortality. Computer-aided analysis of digital images obtained by dermoscopy has been reported to be an accurate, practical and time-saving tool for the evaluation of pigmented skin lesions (PSLs). A prototype for the computer-aided diagnosis of PSLs using artificial neural networks (NNs) has recently been developed: diagnostic and neural analysis of skin cancer (DANAOS).

OBJECTIVES

To demonstrate the accuracy of PSL diagnosis by the DANAOS expert system, a multicentre study on a diverse multinational population was conducted.

METHODS

A calibrated camera system was developed and used to collect images of PSLs in a multicentre study in 13 dermatology centres in nine European countries. The dataset was used to train an NN expert system for the computer-aided diagnosis of melanoma. We analysed different aspects of the data collection and its influence on the performance of the expert system. The NN expert system was trained with a dataset of 2218 dermoscopic images of PSLs.

RESULTS

The resulting expert system showed a performance similar to that of dermatologists as published in the literature. The performance depended on the size and quality of the database and its selection.

CONCLUSIONS

The need for a large database, the usefulness of multicentre data collection, as well as the benefit of a representative collection of cases from clinical practice, were demonstrated in this trial. Images that were difficult to classify using the NN expert system were not identical to those found difficult to classify by clinicians. We suggest therefore that the combination of clinician and computer may potentially increase the accuracy of PSL diagnosis. This may result in improved detection of melanoma and a reduction in unnecessary excisions.

A new approach to dose escalation in non-small-cell lung cancer

PURPOSE

To describe the radiobiological rationale for dose-per-fraction escalation in non-small-cell lung cancer (NSCLC) and to devise a novel Phase I scheme to implement this strategy using advanced radiotherapy delivery technologies.

METHODS AND MATERIALS

The data from previous dose escalation trials in NSCLC are reanalyzed to establish a dose-response relationship in this disease. We also use data relating prolongation in treatment time to survival to compute the potential doubling time for lung tumors. On the basis of these results, and using a Bayesian model to determine the probability of pneumonitis as a function of mean normalized lung dose, a dose-per-fraction escalation strategy is developed.

RESULTS

Standard approaches to dose escalation using 2 Gy per fraction, five fractions per week, require doses in excess of 85 Gy to achieve 50% long-term control rate. This is partly because NSCLCs repopulate rapidly, with a 1.6% per day loss in survival from prolongation in overall treatment time beyond 6 weeks, and a cell doubling time of only 2.5 to 3.3 days. A dose-per-fraction escalation strategy, with a constant number of fractions, 25, and overall time, 5 weeks, is projected to produce tumor control rates predicted to be 10%-15% better than 2 Gy per fraction dose escalation, with equivalent late effects. This Phase I clinical study is divided into three parts. Step 1 examines the feasibility of the maximum breath-holding technique and junctioning of tomotherapy slices. Step 2 treats 10 patients with 30 fractions of 2 Gy over 6 weeks and then reduces duration to 5 weeks using fewer but larger fractions in 10 patients. Step 3 will consist of a dose-per-fraction escalation study on roughly 50 patients, maintaining 25 fractions in 5 weeks. Bayesian methodology (a modification of the Continual Reassessment Method) will be used in Step 3 to allow consistent and efficient escalation within five volume bins.

CONCLUSION

A dose-per-fraction escalation approach in NSCLC should yield superior outcomes, compared to standard dose escalation approaches using a fixed dose per fraction, for a given level of pneumonitis and late toxicity. Highly conformal radiotherapy techniques, such as intensity modulated radiotherapy (IMRT) and helical tomotherapy with its adaptive capabilities, will be necessary to achieve significant dose-per-fraction escalation without unacceptable lung and esophageal morbidity.

Reduced accommodative function in dyskinetic cerebral palsy: a novel management strategy

A 9-year-old boy with dyskinetic cerebral palsy secondary to neonatal encephalopathy is described. He presented with blurring of near vision which had begun to impact on his school work. Objective assessment of accommodation showed that very little was present, although convergence was almost normal. The near-vision symptoms were completely removed and reading dramatically improved with the provision of varifocal spectacles. Varifocal lenses provide an optimal correction for far, intermediate (i.e. for computer screens), and near distances (i.e. for reading). Managing this type of patient with varifocal spectacles has not been previously reported. It is clearly very important to prescribe an optimal spectacle correction to provide clear vision to optimize learning.

A study of the impact of Sun Awareness Week 1995

We report a questionnaire-based survey of parents of schoolchildren to assess the impact of Sun Awareness Week, organized by the U.K. Skin Cancer Working Party, from 4 to 10 June 1995. A questionnaire was designed, pre-tested and modified. Nine hundred and eighty-nine patients of schoolchildren were approached before and after Sun Awareness Week at eight comprehensive primary schools and a children's clothes shop. Responses to the questionnaires were analysed in the following categories: total knowledge, sunscreen knowledge, melanoma risk factor knowledge, attitude, self-reported behaviour and awareness of the link between childhood sun exposure and cancer (link). A reasonable level of knowledge was demonstrated in the sample population. Significant improvements in attitude and behaviour scores were observed (P < 0.05). Three of the four link questions were significantly improved (P < 0.005). These results were not explained by differences in age, sex, or occupation between the before and after populations. Further national studies are needed to establish long-term benefits of such interventions.

Cortical visual dysfunction in children: a clinical study

Damage to the cerebral cortex was responsible for impairment in vision in 90 of 130 consecutive children referred to the Vision Assessment Clinic in Glasgow. Cortical blindness was seen in 16 children. Only 2 were mobile, but both showed evidence of navigational blind-sight. Cortical visual impairment, in which it was possible to estimate visual acuity but generalised severe brain damage precluded estimation of cognitive visual function, was observed in 9 children. Complex disorders of cognitive vision were seen in 20 children. These could be divided into five categories and involved impairment of: (1) recognition, (2) orientation, (3) depth perception, (4) perception of movement and (5) simultaneous perception. These disorders were observed in a variety of combinations. The remaining children showed evidence of reduced visual acuity and/ or visual field loss, but without detectable disorders of congnitive visual function. Early recognition of disorders of cognitive vision is required if active training and remediation are to be implemented.

Balloon cell metastatic melanoma: an important differential in the diagnosis of clear cell tumours

Two cases of metastatic balloon cell melanoma are reported. Each tumour was composed of large clear cells which did not contain melanin, glycogen or fat, but showed positive staining for S-100 protein, NK/1-C3 and HMB-45. In each case the primary lesion was a cutaneous melanoma of typical morphology. It is essential to consider balloon cell melanoma in the differential diagnosis of clear cell tumours. These cases emphasize the need for an accurate clinical history.

Naevi in schoolchildren in Scotland and Australia

To test the hypothesis that children living in subtropical and tropical environments have more naevi than those of similar ethnicity living in temperature countries, a comparative study of melanocytic naevi in 111 schoolchildren from Brisbane, Australia, and 222 from Glasgow, Scotland, was carried out. All children were aged 13-15 years, of European ancestry, and had spent most of their lives at latitudes of less than 30 degrees S (Australia) or greater than 30 degrees N (Scotland). Using an identical protocol, all naevi of 2 mm or more in diameter occurring on the right arm were counted by either a highly experienced research nurse in Brisbane, or a dermatologist in Glasgow. Hair and eye colour, and facial freckling, were assessed by the examiner, and axillary skin colour of children in both cities was measured using the same reflectance spectrophotometer. Children in Brisbane had significantly more naevi than those in Glasgow (P < 0.05), after adjusting for complexion variables. The difference in the geometric mean number of naevi on the arm was much greater among boys (7.7 vs. 4.4, in Brisbane and Glasgow, respectively) than among girls (7.3 vs. 6.7). This has parallels with the sex differences in melanoma at later ages in the two countries. Besides country of residence, freckles and innate skin colour were the most significant predictors of large numbers of naevi, whereas red hair had a significant protective effect. Overall, these data on prevalence of naevi in children from contrasting environments provide some evidence in support of the theory that naevus development is related to the level of sun exposure in childhood and adolescence.

Treatment of arteriovenous malformations with stereotactic radiosurgery employing both magnetic resonance angiography and standard angiography as a database

Twenty-one arteriovenous malformations were prospectively evaluated using magnetic resonance angiography and compared with stereotactic angiography. The goals were to establish the feasibility of magnetic resonance angiography, compare it to stereotactic angiography, employ magnetic resonance angiography in follow-up, and semiquantify flow. A correlative evaluation between flow and response to stereotactic radiosurgery was carried out. Phase contrast angiograms were obtained at flow velocities of 400, 200, 100, 60, and 20 cm/sec. The fractionated velocities provided images that selectively demonstrated the arterial and venous components of the arteriovenous malformations. Qualitative assessment of the velocity within the arteriovenous malformations and the presence of fistulae were also determined by multiple velocity images. In addition, 3-dimensional time-of-flight magnetic resonance angiograms were obtained to define the exact size and shape of the nidus. This technique also permitted evaluation of the nidus and feeding arteries for the presence of low flow aneurysms. Correlation between the two imaging modalities was carried out by subjective and semiquantitative estimation of flow velocity and estimation of nidus size. The following velocity parameters were employed: fast, intermediate, slow, and none (arteriovenous malformation obliterated). In 19 of 21 (90.5%) arteriovenous malformations, magnetic resonance angiography was equal or superior to stereotactic angiography for flow quantification and visualization of the nidus. Only 2 of 21 arteriovenous malformations were better demonstrated by stereotactic angiography than by magnetic resonance angiography (failure rate of 9.5%). The nidus size in one case was clearly underestimated by stereotactic angiography and would have resulted in a geographic miss without magnetic resonance angiography. Seven post-radiosurgery arteriovenous malformations were evaluated for follow-up with both magnetic resonance angiography and stereotactic angiography. In 6 of 7 arteriovenous malformations, magnetic resonance angiography response matched stereotactic angiography response. Correlation of flow with outcome was carried out for 14 arteriovenous malformations using magnetic resonance angiography only. Interestingly, all nine arteriovenous malformations with intermediate or slow flow demonstrated partial or complete obliteration; whereas only 3 of 5 fast flow arteriovenous malformations achieved a response with a median follow-up of 10 months. This early analysis suggests that slower flowing arteriovenous malformations may obliterate faster after stereotactic radiosurgery and flow parameters could be employed to predict response. In conclusion, magnetic resonance angiography permits semiquantitative flow velocity assessment and may therefore be superior to stereotactic angiography. An additional advantage of magnetic resonance angiography is the generation of serial transverse images which can replace the conventional CT scan employed for stereotactic radiosurgery treatment planning.(ABSTRACT TRUNCATED AT 400 WORDS)

A new biomechanical approach to assessing the fragility of the internal elastic lamina of the arterial wall

Patterns of tearing of the internal elastic lamina induced by controlled tensile extension of the arterial wall in the axial direction are similar morphologically to those induced in vivo in the anastomosed arteries of experimental arteriovenous fistulae. The mural response is modelled with a simple bi-layer analogue and it is shown that the internal elastic lamina exhibits a greater degree of strain-limiting deformation behavior in the axial direction than the medial and adventitial layers. Application of laminate theory indicates that the frequency of intimal tearing along the vessel length is directly related to the failure strength of the intimal layer.

Screening for skin cancer

Holidays in sunny climates are taking their toll on British skins. Professor Rona Mackie warns that 'flash frying' attitudes to sun bathing can precipitate skin cancer.

Use of external shock-wave lithotripsy and adjuvant ursodiol for treatment of radiolucent gallstones. A national multicenter study

A prospective multicenter trial was performed to evaluate the use of external shockwave lithotripsy (ESL) and adjuvant medical therapy for the treatment of gallstones. A Medstone STS lithotripter was used together with ursodiol. Two hundred twenty-three patients were treated under general anesthesia (75%) or with intravenous analgesia (25%). Initial treatments were on an inpatient basis, but as centers gained experience, outpatient treatments became more common. Stone fragmentation and clearance were greatest in patients with solitary gallstones less than 2 cm in diameter. In this group of patients, stone fragmentation occurred in 97% of patients, and the cumulative stone-free rates at three and six months were 54% and 90%, respectively. These results indicate that fragmentation of gallstones can be achieved by a dry shock-wave lithotripter and that stone clearance is induced more rapidly by external shock-wave lithotripsy and adjuvant ursodiol therapy than by ursodiol therapy alone.

Phase II studies of mitozolomide in melanoma, lung and ovarian cancer

Seventy-seven patients were treated with oral mitozolomide to assess the activity of this drug in melanoma, lung and ovarian cancer. Partial responses were seen in five of 18 evaluable patients with small cell lung cancer (SCLC) and three of 20 with melanoma. No activity was apparent in non small cell lung or epithelial ovarian cancer. The major toxicity was myelosuppression which necessitated reduction in the initial dosage from 115 to 90 mg/m2. However, even at this dose level, unpredictable WHO grade 4 toxicity occurred in non-pretreated patients. Thrombocytopenia was more common than leucopenia and eight patients required platelet transfusion for spontaneous or tumour-related haemorrhage. Myelotoxicity was considered responsible for two deaths and was a significant contributory factor in a further three. Non-haematological toxicity was minor. Thus, despite demonstrable activity in SCLC and melanoma, unpredictable myelosuppression is likely to preclude further assessment in combination chemotherapy regimes in these tumours.

Staphylococcal colonization in atopic dermatitis and the effect of topical mupirocin therapy

Forty-nine patients with atopic dermatitis entered a double blind placebo controlled cross-over study of mupirocin, a new topical antistaphylococcal antibiotic. Forty-five patients were evaluable. Quantitative bacteriological assessment before treatment showed that heavy colonization of the skin with Staphylococcus aureus was present in nearly all patients even in the absence of overt infection. However, the bacterial count was significantly reduced by 2 weeks' treatment with topical mupirocin, but not by the placebo. Moreover, a significant reduction of clinical severity was also observed after treatment with mupirocin, which was maintained over the following 4 weeks, although recolonization occurred during this period, with bacterial counts rising to pre-treatment levels. Despite recolonization, clinical deterioration was not observed during the trial period. No serious side-effects were observed. Phage typing showed that 50% of patients carried more than one bacterial phage type. Recolonization in eight patients (17%) was with a 'new' strain that had not previously been isolated.

A prospective study of the histological changes in the skin in patients receiving bone marrow transplants

Fourteen patients who received a bone marrow transplant (BMT) as treatment for leukaemia were included in a prospective study of the histological changes in the skin. The aim of this study was to improve the early diagnosis of graft-versus-host disease (GVHD). It was found that the clinically 'normal' pre-transplant skin was in some cases histologically abnormal on H & E examination in patients who were on regular maintenance cytotoxic chemotherapy. These changes were similar to some of the features of GVHD. Immunocytochemistry, although not specific, was found to be helpful in the diagnosis of some cases of GVHD. Suggestive features included a reduction in the numbers of Langerhans cells, an increase in the number of suppressor (OKT8+) cells in the dermal infiltrate and the presence of Ia positivity of the keratinocytes in the epidermis.

Lock-ring for Tenckhoff catheter/titanium adaptor junction

One standard continuous ambulatory peritoneal dialysis (CAPD) infusion/drainage system was found prone to recurrent mechanical failure at the junction between the silastic catheter and the titanium connector. This resulted in slackening and eventual disconnection with attendant risk of bacterial entry and a CAPD-associated peritonitis. A simple "lock-ring" device, when fitted over the catheter-titanium connector junction, afforded a secure joint.

Paradoxical response of malignant melanoma to methotrexate in vivo and in vitro

Methotrexate (MTX) shows consistent cytotoxicity for melanoma cells in vitro but it is ineffective in clinical use at equivalent concentrations in vivo. This apparent paradox has been investigated by cell culture techniques and results quantified by cell number. In an in vitro model of high dose MTX therapy followed by leucovorin rescue (HD-MTX-LCR) there was survival of both melanoma and choriocarcinoma cell lines but not of an acute lymphocytic leukaemia cell line. The 70H metabolite of MTX was identified by HPLC in plasma samples of melanoma patients treated by HD-MTX-LCR, in which MTX concentrations approximately 10(-5) M were maintained for 24 h. However, metabolism per se is unlikely to account for the lack of response to MTX clinically. In vitro 70H MTX (10(-7) - 10(-6) M) was two orders of magnitude less cytotoxic for melanoma than MTX (10(-9) - 10(-8) M). The cellular accumulation of [3H]-MTX, using a rapid gradient centrifuge technique for separation of melanoma cells from medium, was reduced in the presence of 70H-MTX. The results suggest that reduced cellular uptake of MTX combined with biochemical rescue of tumour cells may partially explain the paradoxical lack of clinical response of melanoma to the drug.

Inhibition and recovery of DNA synthesis in PHA-stimulated u.v.-irradiated lymphocytes from patients with actinic keratosis

The recovery, after inhibition by u.v.-irradiation, of phytohaemagglutinin-stimulated DNA synthesis is impaired in lymphocytes from patients with multiple actinic keratoses (AK) compared to the recovery in lymphocytes from age-matched, control individuals. This shows that the reduced level (50%) of DNA repair activity in AK cells is sufficiently different from that in normal cells to significantly affect cellular activity.