Apnoeic and obstructive nonapnoeic sleep respiratory events

Obstructive nonapnoeic event (ONE) scoring is shrouded in confusion. This is important in patients with mild disease, in whom precision is crucial. The aims of the present study were: 1) to identify ONEs using oesophageal pressure (OP) (OP-ONEs) and a noninvasive (NI) method (NI-ONEs); 2) to compare both methods of scoring; and 3) to determine the contribution of ONE definitions to clinical findings. Patients with suspected sleep apnoeas (respiratory disturbance index <or=10) during a first polysomnography were subjected to a second with an OP measurement. OP-ONEs and NI-ONEs were defined as an increase in OP or discernible reduction in the amplitude of thoracoabdominal bands with both desaturation and/or arousal. Bland-Altman analysis established agreement. Comparisons were made between OP-ONEs, NI-ONEs and clinical findings. In our sample (n = 90), the addition of an arousal to the NI-ONEs or OP-ONEs with only desaturation increased the number of NI-ONEs by 329 and 362%, respectively. NI-ONEs with arousal and/or desaturation detected 91% of OP-ONEs. The association with sleepiness depended on the incorporation of arousal into the definition of ONEs. In patients with mild disease, the addition of an arousal to ONEs, with only desaturation, markedly increased respiratory disturbance index, with probable therapeutic implications. Scoring respiratory events as apnoea and ONEs is easier and sufficiently accurate.

Removal of odour-causing compounds using carbonaceous adsorbents/catalysts prepared from sewage sludge

This paper discusses H(2)S, NH(3) and VOCs removal by sewage-sludge-derived materials with outstanding chemical and textural properties. These materials were obtained from different precursors using different chemical and thermal treatments. Results show that the H(2)S removal process entailed a catalytic conversion of H(2)S to S or SO(4) (2-) species. On the other hand, adsorption is the main mechanism governing the performance of sludge-based materials for NH(3) and VOCs. Retention capacities (x/M values) obtained for some of the sludge-based adsorbents/catalysts are similar to those obtained with commercial activated carbons selected as reference materials.

Sr lattice clock at 1 x 10(-16) fractional uncertainty by remote optical evaluation with a Ca clock

Optical atomic clocks promise timekeeping at the highest precision and accuracy, owing to their high operating frequencies. Rigorous evaluations of these clocks require direct comparisons between them. We have realized a high-performance remote comparison of optical clocks over kilometer-scale urban distances, a key step for development, dissemination, and application of these optical standards. Through this remote comparison and a proper design of lattice-confined neutral atoms for clock operation, we evaluate the uncertainty of a strontium (Sr) optical lattice clock at the 1 x 10(-16) fractional level, surpassing the current best evaluations of cesium (Cs) primary standards. We also report on the observation of density-dependent effects in the spin-polarized fermionic sample and discuss the current limiting effect of blackbody radiation-induced frequency shifts.

A novel mathematical model identifies potential factors regulating bone apposition

The development of pharmaceutical treatments for bone disease can be enhanced by mathematical models that predict their effects on matrix apposition during cancellous bone remodelling. Therefore, a mathematical model was constructed to simulate the rate of focal bone formation from the number of osteoid-forming osteoblasts at one microsite and their rate of activity. The number of mature osteoid-forming cells was simulated from a relationship describing the proliferation of preosteoblasts. Osteoblast activity was described by Michaelis-Menten enzyme kinetic equations adapted to describe cellular activity. The model incorporates the negative feedback effects on the rates of bone apposition due to the reduction in size of mature osteoblasts with continuing differentiation and the reduction in number of osteoid-forming cells with apoptosis and osteocyte formation. In addition, the rate of mineralisation is limited according to osteoid substrate availability. Results of sensitivity analysis revealed the amount of bone formed at one microsite to be more sensitive to changes in factors that controlled cell growth during proliferation and the number of mature osteoid-forming osteoblasts than to those that determined cellular activity. Matrix and osteocyte signalling were shown to have potentially important roles in controlling rates of osteoid apposition in normal, healthy bone. This simple model supports the critical role of controlled mitotic growth in normal bone apposition. It can also help to explain how the homeostatic processes of bone resorption and apposition during remodelling can be disrupted by growth factors that affect the mitotic fraction and division time of proliferative preosteoblast cells.

Sensitivity analysis of a novel mathematical model identifies factors determining bone resorption rates

The development of pharmaceutical treatments for bone disease can be enhanced by computational models that predict their effects on resorption and rates of remodeling. Therefore, a simple mathematical model was formulated to simulate erosion depth and duration of resorption, using Michaelis-Menten (M-M) equations to describe changing rates of cellular activity during the two phases of bone resorption. The model was based on histomorphometric data and cellular interactions that occur in the bone microenvironment cited from the literature. Availability of bone substrate for osteoclastic activity during Phase I was assumed to be limited by the ratio of RANKL (ligand for receptor activator for nuclear factor kappaB) to osteoprotegerin (OPG) ('effective RANKL'). The required presence of marrow stromal cell produced macrophage-colony stimulating factor (M-CSF) for osteoclast action was represented as a factor equal to 1 for healthy bone. Growth factors released from the matrix during Phase I were assumed to cause two negative feedback effects: (1) the inhibitory effect of transforming growth factor-beta1 (TGFbeta1)-induced production of OPG by marrow osteoblast stromal cells, reducing effective RANKL; (2) the apoptosis of osteoclast nuclei assumed to occur at high concentrations of TGFbeta. This signaled the end of Phase I. During Phase II, cellular activity to remove the collagen fibrils left behind by osteoclasts was also simulated by Michaelis-Menten kinetic equations. Results of sensitivity analysis revealed variation in resorption depth and duration to fluctuate within 6% and 7% of the baseline value for changes in most input parameters. However, resorption depth was reduced and the duration of resorption lengthened by both a decrease in matrix TGFbeta and an increase the apoptotic threshold. Furthermore, the duration of resorption, but not erosion depth, was sensitive to changes in the maximum rate of cellular activity during removal of collagen fibrils. This mathematical model, which simulates the changing rates of cellular activity, has identified factors that reduce the duration and depth of resorption. It also suggests new targets for modeling therapeutic intervention to slow the rate of bone remodeling.

A prospective randomized multi-center study for the treatment of lumbar spinal stenosis with the X STOP interspinous implant: 1-year results

Patients suffering from neurogenic intermittent claudication secondary to lumbar spinal stenosis have historically been limited to a choice between a decompressive laminectomy with or without fusion or a regimen of non-operative therapies. The X STOP Interspinous Process Distraction System (St. Francis Medical Technologies, Concord, Calif.), a new interspinous implant for patients whose symptoms are exacerbated in extension and relieved in flexion, has been available in Europe since June 2002. This study reports the results from a prospective, randomized trial of the X STOP conducted at nine centers in the U.S. Two hundred patients were enrolled in the study and 191 were treated; 100 received the X STOP and 91 received non-operative therapy (NON OP) as a control. The Zurich Claudication Questionnaire (ZCQ) was the primary outcomes measurement. Validated for lumbar spinal stenosis patients, the ZCQ measures physical function, symptom severity, and patient satisfaction. Patients completed the ZCQ upon enrollment and at follow-up periods of 6 weeks, 6 months, and 1 year. Using the ZCQ criteria, at 6 weeks the success rate was 52% for X STOP patients and 10% for NON OP patients. At 6 months, the success rates were 52 and 9%, respectively, and at 1 year, 59 and 12%. The results of this prospective study indicate that the X STOP offers a significant improvement over non-operative therapies at 1 year with a success rate comparable to published reports for decompressive laminectomy, but with considerably lower morbidity.

Quantitation of PGE9509924, a novel, nonfluorinated quinolone, in rat plasma using liquid chromatography electrospray-tandem mass spectrometry following solid-phase extraction sample clean-up in a 96-well format

PGE9509924, a novel nonfluorinated quinolone, is a potent antibacterial agent with a broad spectrum of activity. A semi-automated method using 96-well format, solid-phase extraction has been developed for quantitating PGE9509924 in rat plasma. The Waters Oasis HLB extraction plate containing a polymeric packing material was found to give the best overall recoveries. All liquid transfer steps other than aliquoting the plasma are accomplished using a 96-channel pipettor. Reverse-phase HPLC with electrospray/MS/MS detection using selective reaction monitoring is used to quantitate the samples. Stable isotopically labeled PGE9509924 is used as the internal standard. The assay is linear over the range from 0.01 to 10 ug/ml. Excellent precision is obtained within a single run and between multiple runs performed on different days. CVs of <6% were observed. The combination of the semi-automated, 96-well parallel sample processing and the short runtime on the LC/MS/MS results in a high throughput assay with reduced operator interaction.

Development of a chiral assay for a novel, nonfluorinated quinolone, PGE-9509924, in dog plasma using high performance liquid chromatography with electrospray tandem mass spectrometry or fluorescence detection

PGE-9509924 is a nonfluorinated quinolone and is active against a variety of susceptible and drug resistant bacteria in vitro and in animal infection models. A method for determining both enantiomers of PGE-9509924 in dog plasma has been developed. The enantiomers are derivatized with a chiral derivatizing agent, (-)-1-(9-fluorenyl)ethyl chloroformate (FLEC) and the resulting diastereomers are separated by reverse phase chromatography. Plasma samples are prepared via solid phase extraction (SPE) in a 96-well format prior to being derivatized. Samples are then analyzed by electrospray-LC/MS/MS with multiple reaction monitoring or by HPLC with fluorescence detection. Results of a side-by-side validation of the method with LC/MS/MS and HPLC/Fl detection are presented. Over the range selected for validation (0.025-10 micro g/ml), both methods give similar results with identical limits of quantitation. Due to the selectivity of LC/MS/MS and the use of a stable-isotopically labeled internal standard, significantly shorter chromatographic runtimes are achieved with LC/MS/MS, making it the method of choice for sample analysis.

Preoperative evaluation of chronic alcoholics assessed for surgery of the upper digestive tract

BACKGROUND

Alcoholics are at risk of developing major complications in the postoperative period. Adequate prophylactic treatment, as well as preoperative abstinence, can significantly decrease the rate of complications. However, the preoperative diagnosis of alcoholism is difficult to establish. The purpose of this study was to assess whether three preoperative visits, an alcohol-related questionnaire (CAGE), and the laboratory markers carbohydrate-deficient transferrin (CDT) and gamma-glutamyltransferase (GGT) would increase the rate of detection of chronic alcoholics.

METHODS

The study included the Departments of ENT, Facial and Maxillofacial Surgery, and General Surgery of a university hospital; 705 male patients were assessed for tumor surgery of the upper digestive tract and were allocated to 5 different groups. All patients were seen three times, and five different strategies were used to detect chronic alcoholics. The gold standard was the diagnosis of alcohol misuse made by an experienced (blinded) investigator according to the DSM-III-R. The main outcome measurements were the detection rates of the different test strategies.

RESULTS

By clinical routine alone, only 16% were detected during the first visit and 34% after three visits. If the CAGE questionnaire was added, sensitivity increased to 64%. The further addition of GGT or CDT led to 80 and 85% detections, respectively. A combination of all tests had a sensitivity of 91%.

CONCLUSIONS

To detect more alcoholic patients at risk for major complications, patients should be seen more often, and additional diagnostic tools such as the CAGE, CDT, and GGT should be used before surgery.

Total colonic manometry as a guide for surgical management of functional colonic obstruction: Preliminary results

BACKGROUND/PURPOSE

Functional colonic obstruction (pseudo-obstruction) encompasses a broad group of motility disorders. Medical management of colonic pseudo-obstruction is complex and often fails, leading to surgical referral. In most cases (excepting Hirschsprung's disease) the surgeon is unable to precisely localize the area of functional obstruction. Total colonic manometry can directly measure intraluminal pressures and contractile function along the entire length of the colon. The authors propose that total colonic manometry can be used by the pediatric surgeon to guide the timing and extent of surgical therapy in refractory functional colonic obstruction.

METHODS

Four patients were evaluated for functional colonic obstruction. All underwent barium enema and rectal biopsy with a diagnosis of Hirschsprung's disease in one patient. All patients underwent colonoscopy and total colonic manometry. Manometric tracings were obtained while fasting, after feeding, and after pharmacologic stimulation both preoperatively (n = 4) and postoperatively (n = 3).

RESULTS

Total colonic manometry identified an abrupt end of normal peristalsis in 2 of the non-Hirschsprung's patients (one in the proximal colon and one in the transverse colon). Medical therapy failed in both of these patients, and they underwent diverting ostomy proximal to the loss of normal peristalsis. The third non-Hirschsprung's patient essentially had normal manometry and was able to have her colon decompressed successfully on a laxative regimen. Repeat manometry after colonic decompression showed return of normal peristalsis in 2 of these patients and continued abnormal peristaltic activity in the third. Definitive surgical intervention based on the results of total colonic manometry was performed on the latter. All 3 patients achieved normal continence. A fourth patient had Hirschsprung's disease confirmed by rectal biopsy and underwent a 1-stage neonatal modified Duhamel procedure, which was complicated by postoperative functional obstruction. Manometry showed a lack of peristaltic function beginning in the right colon. An ileostomy was performed, and timing of ileostomy closure was guided by the return of normal colonic peristalsis seen on manometry.

CONCLUSIONS

These initial cases show the utility of total colonic manometry in the management of colonic pseudo-obstruction syndromes. In addition to its diagnostic utility, direct measurement of colonic motor activity can be valuable in deciding the need for and timing of diversion, the extent of resection, and the suitability of the patient for restoring bowel continuity. In Hirschsprung's disease, total colonic manometry can potentially be used to determine suitability for primary neonatal pull-through versus a staged approach. J Pediatr Surg 36:1757-1763.

Issues in system boundary definition for substance flow analysis: the case of nitrogen cycle management in Catalonia

The great complexity of the nitrogen cycle, including anthropogenic contributions, makes it necessary to carry out local studies, which allow us to identify the specific cause-effect links in a particular society. Models of local societies that are based on methods such as Substance Flow Analysis (SFA), which study and characterise the performance of metabolic exchanges between human society and the environment, are a useful tools for directing local policy towards sustainable management of the nitrogen cycle. In this paper, the selection of geographical boundaries for SFA application is discussed. Data availability and accuracy, and the possibility of linking the results with instructions for decision making, are critical aspects for proper scale selection. The experience obtained in the construction of the model for Catalonia is used to draw attention to the difficulties found in regional studies.

A human CD46 transgenic pig model system for the study of discordant xenotransplantation

BACKGROUND

The chronic shortage in the supply of human organs available for allotransplantation has turned attention toward the use of animals as potential donors, with pigs as the most likely species under consideration. Hyperacute rejection, the initial and immediate barrier to a pig-to-primate xenograft, has been addressed by generation of transgenic pigs that express the human membrane-bound complement-regulatory proteins CD59 and/or CD55. Difficulty has been encountered in generation of transgenic animals that express a third membrane-bound complement-regulatory protein, CD46.

METHODS

We have generated transgenic animals by using a large genomic construct that encompasses the entire human CD46 gene.

RESULTS

We report the first description of transgenic mice and pigs that express high levels of human CD46 in a cell and tissue type-specific manner, resembling patterns of endogenous CD46 expression observed in human tissues. Furthermore, when human CD46 transgenic porcine hearts were transplanted into baboons, the grafts did not succumb to hyperacute rejection, and survival extended for up to 23 days. Under the same conditions, nontransgenic grafts underwent hyperacute rejection within 90 min.

CONCLUSIONS

This is the first report to describe generation of transgenic pigs that express human CD46, and the first in vivo demonstration of the ability of human CD46 expressed on pig organs to regulate complement activation and overcome hyperacute rejection upon transplantation of a vascularized organ into nonhuman primates.

Simulating the growth response of aspen to elevated ozone: a mechanistic approach to scaling a leaf-level model of ozone effects on photosynthesis to a complex canopy architecture

Predicting ozone-induced reduction of carbon sequestration of forests under elevated tropospheric ozone concentrations requires robust mechanistic leaf-level models, scaled up to whole tree and stand level. As ozone effects depend on genotype, the ability to predict these effects on forest carbon cycling via competitive response between genotypes will also be required. This study tests a process-based model that predicts the relative effects of ozone on the photosynthetic rate and growth of an ozone-sensitive aspen clone, as a first step in simulating the competitive response of genotypes to atmospheric and climate change. The resulting composite model simulated the relative above ground growth response of ozone-sensitive aspen clone 259 exposed to square wave variation in ozone concentration. This included a greater effect on stem diameter than on stem height, earlier leaf abscission, and reduced stem and leaf dry matter production at the end of the growing season. Further development of the model to reduce predictive uncertainty is discussed.

Melatonin profiles and sleep characteristics in boys with fragile X syndrome: a preliminary study

Sleep patterns and endogenous melatonin profiles in 13 fragile X boys between the age of 4.7 and 11.0 years were compared to those of 8 age-matched, normal control boys. Parents recorded sleep patterns on a Sleep Diary Chart for 14 consecutive days. Twelve saliva samples were obtained from 8 fragile X participants and all of the controls over 48 hours for the assessment of salivary melatonin profiles. The results showed greater variability in total sleep time and difficulty in sleep maintenance in fragile X boys compared with the control participants. Nocturnal melatonin production, expressed as both peak level and area under the concentration-time curve between 20:00 h and 08:00 h, were found to be significantly larger in fragile X boys than in controls. Additionally, the mean of the minimum daytime melatonin levels recorded was significantly higher for the fragile X group. Elevated levels in some fragile X boys relative to the range seen in controls, occurring either during the day or at night, or in both segments of the secretory profile for some individuals, may be due in part to overactivity of the sympathetic nervous system. Alternative molecular mechanisms leading to changes in melatonin profiles in fragile X are also discussed.

Development of in vivo-matured porcine oocytes following intracytoplasmic sperm injection

The objective of this study was to assess the development of porcine ova fertilized by intracytoplasmic sperm injection (ICSI). Allyl trenbolone (Regumate) was used to synchronize estrus in 13 postpuberal gilts. Gilts were superovulated with pregnant mare serum gonadotropin and hCG. Ova were aspirated from 5- to 8-mm follicles at 36 h after hCG. Cumulus cells were removed by blunt dissection and pipetting in Beltsville embryo culture medium (BECM) supplemented with 0.1% hyaluronidase. Sperm were washed and resuspended in BECM + 8% polyvinylpyrrolidone. Ova (n = 237) that exhibited a polar body were centrifuged at 15 000 x g for 6 min and injected with a single spermatozoon. One hundred fifty-four ova were cultured in NCSU-23 medium in a 5% CO(2) in air environment for 168 h. Ova were fixed in acetic acid/ethanol and stained with 1% orcein. Sixty-nine ICSI ova were cultured for 24 h and transferred (mean = 23) to three recipients. Eighty-one ova (69%) that survived ICSI cleaved within 48 h. Thirty-eight percent (31/81) of these ova became blastocysts (mean +/- SEM = 24.7 +/- 1.1 cells). One recipient gave birth to three pigs. These results demonstrate that porcine embryos derived from ICSI can develop into live pigs.

CD46 transgene expression in pig peripheral blood mononuclear cells does not alter their susceptibility to measles virus or their capacity to downregulate endogenous and transgenic CD46

CD46 (or membrane cofactor protein) protects autologous cells from complement-mediated lysis and has been expressed as a transgene in pigs to overcome complement-mediated hyperacute rejection of porcine organs upon transplantation into primates. Since CD46 has been identified as a receptor for measles virus (MV), the susceptibility of CD46-transgenic (tg) pig peripheral blood mononuclear cells (PBMC) to infection with MV strains which do and do not use CD46 as receptor was investigated. Surprisingly, it was found that MV vaccine strains (e.g. Edmonston) bound to tg as well as non-tg pig PBMC. Phytohaemagglutinin-stimulated CD46-tg and non-tg pig PBMC were equally well infected with MV vaccine strains irrespective of CD46 expression. Upon infection, tg CD46 was downregulated from the cell surface. In contrast, the binding capacity for MV wild-type strains to pig and human PBMC was low, irrespective of CD46 expression. These MV strains did not infect tg or non-tg pig cells. Expression of endogenous pig CD46 was detected with polyclonal sera against human CD46. After infection of pig PBMC with MV strain Edmonston, endogenous pig CD46 was also downregulated. This suggests an interaction between MV Edmonston and pig CD46. However, polyclonal CD46 sera did not inhibit infection with MV Edmonston indicating that CD46 may not exclusively act as a receptor for MV on these cells. Interestingly, similar results were observed using human PBMC. Data suggest that CD46 downregulation after interaction with MV may also occur in porcine organs which express endogenous and/or human CD46 as a means of protection against complement-mediated damage.

The role SWISS-PROT and TrEMBL play in the genome research environment

SWISS-PROT, a curated protein sequence data bank, contains not only sequence data but also annotation relevant to a particular sequence. The annotation added to each entry is done by a team of biologists and comes, primarily, from articles in journals reporting the actual sequencing and sometimes characterisation. Review articles and collaboration with external experts also play a role along with the use of secondary databases like PROSITE and Pfam in addition to a variety of feature prediction methods. Annotation added by these methods is checked for relevance and likelihood to a particular sequence. The onset of genome sequencing has led to a dramatic increase in sequence data to be included in SWISS-PROT. This has led to the production of TrEMBL (Translation of the EMBL database). TrEMBL consists of entries in a SWISS-PROT format that are derived from the translation of all coding sequences in the EMBL nucleotide sequence database, that are not in SWISS-PROT. Unlike SWISS-PROT entries those in TrEMBL are awaiting manual annotation. However, rather than just representing basic sequence and source information, steps have been taken to add features and annotation automatically. In taking these steps it is hoped that TrEMBL entries are enhanced with some indication as to what a protein is, could or may be.

Metabolism of antisense oligonucleotides in rat liver homogenates

Phosphorothioate antisense oligodeoxynucleotides are novel therapeutic agents designed to selectively and specifically inhibit production of various disease-related gene products. In vivo pharmacokinetic experiments indicate that these molecules are widely distributed in many species, with the majority of oligomers accumulating within liver and kidney. To better understand the metabolism of these agents, we studied the stability of several phosphorothioate oligodeoxynucleotides, their congeners, and second generation oligomer chemistries in rat liver homogenates. To examine metabolism, background nuclease activity was characterized in whole liver homogenates by using ISIS 1049, a 21-mer phosphodiester oligodeoxynucleotide. Nuclease activity could readily be detected in liver homogenates. Under optimized conditions, the predominant enzymatic activity was 3'-exonucleolytic and could be influenced by pH and ionic conditions. However, in addition to 3' exonucleases, 5' exo- and endonuclease activities were also observed. Our data indicate that metabolism of phosphorothioate oligodeoxynucleotides was more complex than that of phosphodiesters for many reasons, including phosphorothioate oligodeoxynucleotide inhibition of nucleases and the presence of R(p) and S(p) stereoisomers. The rate of phosphorothioate metabolism also appeared to be influenced by sequence, with pyrimidine-rich compounds being metabolized to a greater extent than purine-rich oligomers. Other factors affecting stability included oligomer chemistry and length. Concomitant experiments performed in rats dosed systemically with the same compounds mimic the activities seen in vitro and suggest that this liver homogenate system is a valuable model with which to study the mechanism of metabolism of antisense oligonucleotides.

13C-urea breath test for the diagnosis of Helicobacter pylori infection before treatment: is citric acid necessary?

AIM

13C-urea breath test is one of the best methods for the diagnosis of Helicobacter pylori infection. Although a citric acid solution is generally used prior to urea intake, the superiority of this strategy has not been sufficiently demonstrated. Thus, our aim was to compare 13C-urea breath test with and without citric acid solution, to evaluate whether 13C-urea breath test can also achieve favourable results when the test meal is omitted.

METHODS

13C-urea breath test with and without citric acid were compared prospectively in 53 subjects without prior Helicobacter pylori eradication therapy prescription. Basal samples and at 15', 30', and 45' after taking 100 mg of 13C-urea were obtained. The gold standard for Helicobacter pylori diagnosis was the 13C-urea breath test result with citric acid at 30', and "Delta Over Baseline" values >5 at that time were considered positive.

RESULTS

The prevalence of Helicobacter pylori infection was 68%. Mean Delta Over Baseline values with citric acid at 15', 30' and 45' were: 29.6+/-39, 30.8+/-37 and 24.6+/-27; whereas respective values without citric acid were lower: 14.9+/-22, 12.2+/-17 and 10D+/-13 (p<O. 001 for all comparisons, Wilcoxon test for paired data). Thus, the area under the curve (constructed with Delta Over Baseline values at different times) with citric acid was 85+/- 102, and 37+/-50 without citric acid [p<0.001). Correlation coefficient between Delta Over Baseline values with and without citric acid at 30' was 0.73 (p<0.0001). The percentage of subjects achieving the highest Delta Over Baseline value at 15', 30' and 45' with citric acid was 51%, 30% and 19%, whereas without citric acid it was 51%, 26% and 23% (non-significant differences). The area under receiver operating characteristic curve for 13C-urea breath test without citric acid was: 0.98 at 15', 1 at 30' and 0.97 at 45'. The best cut-off point for 13C-urea breath test without citric acid at 30' was anywhere between 3. 3 and 3.9 (that is, a lower value than that usually considered with citric acid), with 100% (95% confidence interval, 90-100%) sensitivity and 100% [82-100%) specificity

CONCLUSIONS

13C-urea breath test values with citric acid are higher than those obtained without citric acid, although this difference does not imply a diagnostic superiority in untreated patients when considering 13C-urea breath test without citric acid at 30'. Therefore, for the diagnosis of Helicobacter pylori infection in untreated patients, citric acid solution in 13C-urea breath test protocol can be omitted.

Angiogenic cytokines in mesothelioma: a study of VEGF, FGF-1 and -2, and TGF beta expression

Vascular endothelial growth factor (VEGF), acidic and basic fibroblast growth factors (FGF-1 and -2), and transforming growth factor beta (TGFbeta) are potent angiogenic cytokines. Malignant mesothelioma of the pleura presents with a high intra-tumoural microvascular density (IMD) which also has prognostic relevance. This study was designed to verify the immunohistochemical expression of the angiogenic cytokines in mesothelioma as well as in non-neoplastic human mesothelial cells and to study the individual as well as the combined expression of these cytokines in mesothelioma in relation to both IMD and prognosis. In addition, four mesothelioma cell lines were studied by ELISA for the secretion of VEGF and FGF-2 in their supernatants and were shown to contain high levels of both of these cytokines. Immunohistochemically, VEGF, FGF-1 and -2, and TGFbeta immunoreactivity was present in 81, 67, 92 and 96 per cent of mesotheliomas, and in 20, 50, 40, and 10 per cent of samples of the non-neoplastic mesothelium, respectively. Co-ordinate expression of the cytokines was observed whereby mesotheliomas expressed more than one cytokine. The combined immunohistochemical expression levels for all four cytokines correlated significantly with both IMD (p=0.01) and prognosis (p=0. 0013). When studied individually, high FGF-2 expression correlated best with more tumour aggressiveness and worse prognosis for mesothelioma (p=0.0011). There was no significant correlation between prognosis and immunoexpression of VEGF (p=0.07), FGF-1 (p=0.3), or TGFbeta (p=0.1), or between IMD and any of the cytokines studied individually. These data support the assertion that selective angiogenic cytokines might contribute to the progressive changes of mesothelioma by tumour angiogenesis.

Return of the internal jugular vein--development of collateral drainage following neonatal ligation of the vein

The development of collateral venous drainage in the neck of a child, who as a neonate had undergone ligation and cannulation of the right internal jugular vein, is described. The resultant vessels were of sufficient calibre to be considered as potential sites for vascular access, although it is possible that their course in the thorax may preclude correct placement of a central venous catheter. Nevertheless, we feel that this case further illustrates the benefit of hand-held ultrasonography in visualizing the vascular structures of the neck. Moreover, ligation of a vein in the neonatal period should not be a contraindication to subsequent assessment of that site for vascular access.

Removing redundancy in SWISS-PROT and TrEMBL

SUMMARY

One of the distinguishing criteria of the SWISS-PROT protein sequence data bank is minimal redundancy. The introduction of TrEMBL as a supplementary database ensured the comprehensiveness of SWISS-PROT and TrEMBL but introduced some degree of redundancy. We developed a strategy to identify the redundancy present within and between SWISS-PROT and TrEMBL and its subsequent removal.

AVAILABILITY

The tools mentioned in this paper are available on request.

Changes in human plasma melatonin profiles in response to 50 Hz magnetic field exposure

The effects of power-frequency magnetic fields on nighttime plasma melatonin were studied in a group of 30 adult male human subjects. Exposure consisted of 20 microT (200 mG) at 50 Hz (circularly polarized) at certain times in relation to the predicted time of onset of rise in melatonin concentration for a particular individual (the time of onset was predicted from a previous screening night). Response to this exposure was compared to sham-exposure (in random order). When exposure preceded onset of rise, a significant delay in onset time relative to sham-exposure of approximately half an hour was observed, with indications (marginally significant) of a reduction in maximum melatonin level. Analysis of distribution of time-delays is consistent with two populations: those individuals who respond (around 20%) and those that do not. Magnetic fields generated by square-wave currents produce more marked reductions in the maximum level when compared to sinusoidal waveforms, but there was no significant difference in onset time.

In vivo distribution and metabolism of a phosphorothioate oligonucleotide within rat liver after intravenous administration

In the rat, the liver represents a major site of phosphorothioate oligodeoxynucleotide deposition after i.v. administration. For this reason, we examined the intracellular fate of ISIS 1082, a 21-base heterosequence phosphorothioate oligodeoxynucleotide, isolated from parenchymal and nonparenchymal cell types after systemic dosing using established perfusion and separation techniques followed by CGE. Isolated cells were further fractionated into nuclear, cytosolic and membrane constituents to assess the intracellular localization, distribution and metabolic profiles as a function of time and dose. After a 10-mg/kg i.v. bolus, intracellular drug levels where maximal after 8 hr and diminished significantly thereafter, suggesting an active efflux mechanism or metabolism. Nonparenchymal (i.e., Kupffer and endothelial) cells contained approximately 80% of the total organ cellular dose, and this was equivalently distributed between the two cell types, while the remaining 20% was associated with hepatocytes. Nonparenchymal cells contained abundant nuclear, cytosolic and membrane drug levels over a wide dose range. In contrast, at doses of less than 25 mg/kg, hepatocytes contained significantly less drug with no detectable nuclear-association. Doses at or above 25 mg/kg appeared to saturate nonparenchymal cell types, whereas hepatocytes continued to accumulate drug in all cellular compartments, including the nucleus. Our results suggest that although pharmacokinetic parameters vary as a function of hepatic cell type, significant intracellular delivery can be readily achieved in the liver after systemic administration.