Evaluation of minimally invasive analysis system for cough leak point pressure measurement

PURPOSE

Leak point pressure (LPP) measurement has become standard in the diagnosis of stress urinary incontinence. Leak point pressure is determined by increasing abdominal pressure, which can be done with a Valsalva maneuver or coughing, that is Valsalva LPP and cough LPP (CLPP). It may be influenced by catheter size, bladder volume and interobserver variability. A new, computerized LPP measuring technique for routine use in daily urodynamic practice was tested at a female unit urodynamic practice to evaluate female urinary incontinence.

MATERIALS AND METHODS

A total of 28 female patients with a mean age of 54.07 years (range 23 to 82) and urinary incontinence underwent a new, minimally invasive measurement of the cough leak point. Measurements are made with the patient standing and repeated 3 times per patient. Additionally, parameters of the corresponding leak were recorded simultaneously. All patients underwent new CLPP measurement and a standard, complete urodynamic investigation, including filling cystometry with abdominal LPP and urethral pressure profile at rest. Statistical evaluation was done by linear regression analysis and the correlation coefficients among CLPP, age, standard abdominal LPP and maximum urethral pressure, and among the 3 measurements for each patient.

RESULTS

: The assignment of leakage to the pressure signal presented no problem. All CLPP data were reproducible in the 3 repeated measurements per patient. No correlation was seen between CLPP and abdominal LPP or the urethral pressure profile.

CONCLUSIONS

The study confirm that the CLPP is a practicable, consistent and minimally invasive method in routine use. Clinical use is easy and reproducible, and only 1 catheter is required for measurement.

Computer-identified nuclear localization signal in exon 1A of the transporter DMT1 is essentially ineffective in nuclear targeting

Divalent metal transporter 1 (DMT1; also called DCT1, Nramp2, or SLC11A2) has multiple isoforms that localize differently in many cell types. DMT1 +IRE species (encoded by mRNA with an iron-responsive element) are limited to the plasma membrane and cytosolic vesicles. In neural cells, -IRE isoforms of DMT1 (encoded by mRNA lacking an IRE) localize to the nucleus, plasma membrane, and cytosolic vesicles. In considering nuclear compartmentalization of -IRE isoforms, we hypothesized that the newly identified exon 1A in the N-terminus of this transporter might contain a nuclear localization signal. DNA constructs starting with exon 1A and ending with exons encoding alternative isoforms were made and transiently transfected into HEK293T and PC12 cells as well as rat sympathetic neurons. None of the constructs appeared in the nucleus despite the presence of exon 1A. Antibody specific for exon 1A was also used in both immunostaining and Western blots to investigate localization of exon 1A expressed both endogenously and ectopically in cells. Again, nuclear localization of DMT1 containing exon 1A was not observed. Our data suggest that exon 1A is neither sufficient nor necessary for DMT1 to appear in the nucleus.

Determination of Cryptosporidium parvum oocyst viability by fluorescence in situ hybridization using a ribosomal RNA-directed probe

AIMS

Fluorescence in situ hybridization (FISH) has been proposed for species-specific detection, and viability determination of Cryptosporidium parvum oocysts. FISH-based viability determination depends on rRNA decay after loss of viability. We examined the effects of RNase(s) and RNase inhibitors on FISH of C. parvum.

METHODS AND RESULTS

FISH was performed using a 5'-Texas red-labelled DNA oligonucleotide probe at 1 pM microl(-1). Intact and heat-permeabilized oocysts were treated with 1-100 microg ml(-1) RNase. FISH of intact oocysts appeared unaffected by exogenous RNase if this was neutralized before permeabilization. FISH fluorescence of heat-killed oocysts stored in phosphate-buffered saline at room temperature decayed by 1/2 after 55 h, but remained detectable after 6 days. Addition of vanadyl ribonucleoside complex (VRC) extended rRNA half-life of heat-permeabilized oocysts to 155 h.

CONCLUSIONS

Extended rRNA half-life may result in viability overestimation using FISH. RNase pretreatment before FISH is recommended to destroy residual rRNA in recently killed oocysts. Incorporation of 1-10 mM l(-1) VRC before FISH permeabilization steps should neutralize RNase activity.

SIGNIFICANCE AND IMPACT OF THE STUDY

Elimination of FISH fluorescence of nonviable C. parvum is desirable. Use of RNase and VRC is suggested to reduce numbers of false-positive 'viable' oocysts.

Metagenomics, gene discovery and the ideal biocatalyst

With the rapid development of powerful protein evolution and enzyme-screening technologies, there is a growing belief that optimum conditions for biotransformation processes can be established without the constraints of the properties of the biocatalyst. These technologies can then be applied to find the ‘ideal biocatalyst’ for the process. In identifying the ideal biocatalyst, the processes of gene discovery and enzyme evolution play major roles. However, in order to expand the pool genes for in vitro evolution, new technologies, which circumvent the limitations of microbial culturability, must be applied. These technologies, which currently include metagenomic library screening, gene-specific amplification methods and even full metagenomic sequencing, provide access to a volume of ‘sequence space’ that is not addressed by traditional screening.

Review and re-analysis of domain-specific 16S primers

The Polymerase Chain Reaction (PCR) has facilitated the detection of unculturable microorganisms in virtually any environmental source and has thus been used extensively in the assessment of environmental microbial diversity. This technique relies on the assumption that the gene sequences present in the environment are complementary to the "universal" primers used in their amplification. The recent discovery of new taxa with 16S rDNA sequences not complementary to standard universal primers suggests that current 16S rDNA libraries are not representative of true prokaryotic biodiversity. Here we re-assess the specificity of commonly used 16S rRNA gene primers and present these data in tabular form designed as a tool to aid simple analysis, selection and implementation. In addition, we present two new primer pairs specifically designed for effective "universal" Archaeal 16S rDNA sequence amplification. These primers are found to amplify sequences from Crenarchaeote and Euryarchaeote type strains and environmental DNA.

Characterization of the metabolic burden onEscherichia coli DH1 cells imposed by the presence of a plasmid containing a gene therapy sequence

The presence of a plasmid, containing gene sequences for DNA immunotherapy that are not expressed in microbial culture, imposed a degradation in bioreactor performance in cultures of the host E. coli strain. Significant decreases in growth rate (24%) and biomass yield (7%) and a corresponding increase in overflow metabolism were observed in a strain containing a therapeutic sequence (a hepatitis B antigen under the control of a CMV promotor). The observed increase in overflow metabolism was incorporated into a Metabolic Flux Analysis (MFA) model (as acetate secretion). Metabolic flux analysis revealed an increase in TCA cycle flux, consistent with an increased respiration rate observed in plasmid-containing cells. These effects are thought to result from increased ATP synthesis requirements (24%) arising from the expression of the Kanr plasmid marker gene whose product accounted for 18% of the cell protein of the plasmid-containing strain. These factors will necessitate significantly higher aeration and agitation rates or lower nutrient feed rates in high-density cultures than would be expected for plasmid-free cultures.

Comparison of CT and MRI in the pre-operative staging of rectal adenocarcinoma and prediction of circumferential resection margin involvement by MRI

OBJECTIVE

It has been suggested that MRI may be used as the sole modality of choice in pre-operative staging in rectal cancers. Knowledge of tumour stage and a threatened Circumferential Resection Margin (CRM) pre-operatively are essential for planning neo-adjuvant therapy and as predictors of local recurrence. At present most units utilize CT scanning to assess these parameters. The aim of our study was two fold: firstly to examine the accuracy of preop CT and MRI staging of rectal cancers compared with final histology and secondly to assess the accuracy of MRI in predicting penetration of the mesorectal envelope (ME).

PATIENTS AND METHODS

All patients with biopsy proven rectal adenocarcinoma underwent thin slice MRI and CT scan pre-operatively. Forty-seven patients have been prospectively entered into the study: 24 male (median age 68 years; range 38-91 years). Eleven patients were unsuitable for surgery leaving 36 patients available for study.

RESULTS

CT correctly staged patients with T1/T2 rectal cancers more often than MRI (77% vs. 43%, P = 0.226). Patients with T1/T2 tumours were overstaged more often by MRI compared with CT (54% vs. 23%, P = 0.226). A greater proportion of patients with T3 tumours were correctly staged by MRI than CT (76% vs. 41%, P = 0.08); and more T3 disease was understaged by CT than MRI (54 vs. 18%, P = 0.032). CT and MRI staged T4 disease equally. In the assessment of mesorectal envelope integrity, MRI had a sensitivity of 80% and a specificity of 84%. The positive predictive value was 44% and the negative predictive value 96%.

CONCLUSIONS

These results suggest significant differences between accurate pre-operative "T" staging by CT and MRI for rectal cancer. MRI has the potential however, to accurately assess mesorectal envelope invasion. Further analysis is required to assess whether MRI can be used as the sole modality in pre-operative staging of rectal cancers.

Randomized controlled trial of four-layer bandaging and simple venous surgery for venous ulceration

Background

No randomized controlled trials exist to show whether simple venous surgery benefits healing or maintenance of healing of venous ulcers.

Methods

Some 121 consecutive patients with new episodes of venous ulceration were identified; 45 patients were unfit or unwilling for randomization. The remaining 76 (39 women) were assigned randomly to received a four-layer bandage (n = 39) or simple venous surgery (n = 37). All patients were followed for a minimum of 6 months. Outcome was assessed at a minimum of 6 months as healing and health-related quality of life (HRQL).

Results

The two groups had similar co-morbidity and pattern of venous incompetence. There were no major complications in either group. The healing rate was 64 per cent (25 of 39) in the conservatively treated group and 68 per cent (25 of 37) in the operated group (P = 0·75, Pearson χ2 test). There was no significant difference between time to ulcer healing in the two treatment groups (log rank statistic = 0·69, P = 0·41). Patterns of venous incompetence did not affect the healing rate. There were no major differences in HRQL between the two groups.

Conclusion

This pilot study suggests that simple venous surgery gives no adjuvant benefit to four-layer bandaging in venous ulceration from the point of view of healing rate and quality of life.

Major colorectal cancer resection should not be denied to the elderly

AIMS

Adjuvant therapy after surgery for colorectal cancer is often denied to the elderly for various reasons. This study was to determine morbidity and mortality risk after surgery in the elderly and whether this is affected by adjuvant therapy.

METHODS

Data were collected prospectively and entered on a database for all patients undergoing resection of colorectal cancer between January 1994 and July 2000. A total of 304 patients were included, 65 aged 80 years and over.

RESULTS

There were 84 deaths, 21 (30%) in the over 80s, and 63 (26%) in the under 80s (P=0.51). The 'in-hospital' mortality was 10.1% in the over 80s and 3.8% in the under 80s (P=0.056). In the over 80s the colon was more affected than the rectum (P=0.002). The over 80s were less likely to be offered adjuvant therapy, 7.2% vs 42.1% (P<0.001). The 5 year survival (all-cause mortality) in the over 80s was 58.5% and 47.6% in the under 80s (P=0.25). Cox's regression analysis of all patients identified the following factors to be independently related to overall survival: age>80 years, post-operative leak, increasing Dukes stage and distant recurrence of disease.

CONCLUSION

This study has demonstrated that surgery should not be denied to elderly patients with colorectal cancer as despite a higher post-operative morbidity and mortality rate and with the absence of adjuvant therapy, favourable long-term outcome can be achieved by resectional surgery alone.

Randomised trial of pre-operative colour duplex marking in primary varicose vein surgery: outcome is not improved

OBJECTIVE

the ability of colour duplex to accurately locate incompetent venous sites has been widely published; its value in pre-operative marking in simple primary varicose vein surgery is evaluated in this study.

DESIGN OF STUDY

prospective randomised controlled trial.

SETTING

regional vascular service, hospital patients.

SUBJECTS

consecutive patients (149) undergoing primary varicose vein surgery where the only difference was one group of patients received duplex marking prior to surgery. Six weeks and 12 months post-operatively all patients had a colour duplex scan to determine the accuracy of surgery and the presence of residual/recurrent varicose veins and completed the Aberdeen, SF-36, and EuroQol quality of life questionnaires.

INTERVENTIONS

varicose vein surgery.

MAIN OUTCOME MEASURES

Duplex evidence of venous incompetence, quality of life measures using the SF-36 and Aberdeen Varicose Veins Questionnaire.

RESULTS

pre-operative marking of primary varicose veins by skilled duplex ultrasonography does not improve the accuracy or recurrence rate following surgery. Quality of life improved significantly following surgery in both groups, however there was no difference in this improvement between the groups.

CONCLUSION

the trial has not demonstrated any additional benefit of pre-operative colour duplex marking over that of clinical and hand held Doppler marking in terms of satisfactory varicose vein surgery performance at 6 weeks or 12 months in patients with primary varicose veins of the long saphenous system. It role in the short saphenous system is less clear.

Native Vaccinium spp. and Gaylussacia spp. infested by Rhagoletis mendax (Diptera: Tephritidae) in the Great Lakes Region: a potential source of inoculum for infestation of cultivated blueberries

In this study, we addressed the question of whether or not native stands of blueberry (Vaccinium spp.) and/or huckleberry (Gaylussacia spp.) support populations of blueberry maggot, Rhagoletis mendax Curran, in the Great Lakes region. Infestation of commercial blueberries by the blueberry maggot, R. mendax, is a serious problem in many areas where blueberries are grown. In the past 10-20 yr, commercial bighbush blueberry, Vaccinium corymbosum L., production has expanded into places such as southern Ontario and southern Quebec where blueberry maggot had not previously been reported. In the mid-1990s, isolated infestations of commercial highbush blueberry were reported in southern Ontario. Because R. mendax was not considered endemic to that area, it was widely assumed that the pests had come into the fields via movement from exotic localities. Here we present an alternative hypothesis, that the blueberry maggots infesting newly established highbush plantations are derived from native blueberries growing in the vicinity. To test this hypothesis, in 1997-1999, we sampled potential native hosts for R. mendax (Vaccinium spp. and Gaylussacia spp.) from 31 localities in the Great Lakes region, primarily in Michigan and Ontario. R. mendax was reared from fruits of native hosts collected at four sites in Michigan and one site each in Ontario, Indiana, and Ohio. V. corymbosum was the predominant host infested, with infestation of this host observed at five of the seven sites. However, two huckleberry species [Gaylussacia baccata (Wangenheim) K. Koch, and Gaylussacia dumosa (Andersson) Torrey & Gray] had the highest rates of infestation that we observed (25.4 and 17.6%, respectively). These data represent the first published reports of R. mendax infesting native host plants in the Great Lakes region, and support the hypothesis that infestations observed in commercial fields may have originated from infested native host plants.

Trimethoprim-sulfamethoxazole (TMP-SMZ) dose escalation versus direct rechallenge for Pneumocystis Carinii pneumonia prophylaxis in human immunodeficiency virus-infected patients with previous adverse reaction to TMP-SMZ

Trimethoprim-sulfamethoxazole (TMP-SMZ) is the most effective Pneumocystis carinii pneumonia (PCP) prophylactic agent, but adverse reactions are common among human immunodeficiency virus (HIV)-infected patients and limit its use. This randomized, double-blind controlled trial compared 2 methods of TMP-SMZ reintroduction, 6-day dose escalation and direct rechallenge, for PCP prophylaxis in HIV-infected patients who had experienced previous treatment-limiting reactions. The primary end point was the ability to take single-strength TMP-SMZ daily for 6 months. Seventy-five percent of the dose-escalation group and 57% of the direct-rechallenge group continued to receive daily single-strength TMP-SMZ for 6 months (P= .014). Among premature discontinuations, 58% of the dose-escalation group and 70% of the direct-rechallenge group were due to adverse reactions. None of these reactions was serious. This study provides evidence that it is possible to successfully reintroduce TMP-SMZ to a significant proportion of HIV-infected patients who have experienced mild-to-moderate treatment-limiting adverse reactions.

Development of a PCR test for the detection of Curtobacterium flaccumfaciens pv. flaccumfaciens

A chromosomal DNA library of the bacterial pathogen of bean, Curtobacterium flaccumfaciens pv.flaccumfaciens NCPPB 559 was constructed in the plasmid pGEM-7Zf(+). Several clones were identified that hybridised to all Curtobacterium flaccumfaciens pathovars including: C. f betae, C. f flaccumfaciens, C. f oortii, C. f. poinsettiae and, in addition, to some strains of Clavibacter michiganensis subsp. insidiosus and Clavibacter michiganensis subsp. One of these clones (pPMP-26), after subsequent digestion with restriction endonucleases EcoRI/SacI, yielded a fragment of approximately 0.2 Kb (pPMP-26D) that hybridised specifically to C. f flaccumfaciens and not to any of the other plant pathogenic members of the order Actinomycetales or any of the other prokaryotic bean pathogens tested. This fragment was subcloned and sequenced, analysis of the resultant 198 bp sequence showed that no significant homology existed with any other sequence currently deposited in public databases. Further analysis of these data facilitated the design of PCR primers which were subsequently tested against a wide range of plant pathogenic actinomycetes and other prokaryotic bean pathogens. Results show that these primers are highly specific for all strains of C. f flaccumfaciens with no cross-reaction to strains from any other bacterial taxa tested.

cAMP stimulation of HCO3- secretion across airway epithelia

To test for the presence of HCO(3)(-) transport across airway epithelia, we measured short-circuit current in primary cultures of canine and human airway epithelia bathed in a Cl(-)-free, HCO(3)(-)/CO(2)-buffered solution. cAMP agonists stimulated a secretory current that was likely carried by HCO(3)(-) because it was absent in HCO(3)(-)-free solutions. In addition, the cAMP-stimulated current was inhibited by the carbonic anhydrase inhibitor, acetazolamide, and by the apical addition of a blocker of cystic fibrosis transmembrane conductance regulator (CFTR), diphenylamine-2-carboxylate. The current was dependent on Na(+) because it was inhibited by removing Na(+) from the submucosal solution and by inhibition of the Na(+)-K(+)-ATPase with ouabain. The cAMP-stimulated current was absent in cystic fibrosis (CF) airway epithelia. These data suggest that cAMP agonists can stimulate HCO(3)(-) secretion across airway epithelia and that CFTR may provide a conductive pathway for HCO(3)(-) movement across the apical membrane.

Peroxisome biogenesis in the yeast Yarrowia lipolytica

Extensive peroxisome proliferation during growth on oleic acid, combined with the availability of excellent genetic tools, makes the dimorphic yeast, Yarrowia lipolytica, a powerful model system to study the molecular mechanisms involved in peroxisome biogenesis. A combined genetic, biochemical, and morphological approach has revealed that the endoplasmic reticulum (ER) plays an essential role in the assembly of functional peroxisomes in this yeast. The trafficking of some membrane proteins to the peroxisomes occurs via the ER, results in their glycosylation in the ER lumen, does not involve transit through the Golgi, and requires the products of the SEC238, SRP54, PEX1, and PEX6 genes. The authors' data suggest a model for protein import into peroxisomes via two subpopulations of ER-derived vesicles that are distinct from secretory vesicles. A kinetic analysis of the trafficking of peroxisomal proteins in vivo has demonstrated that membrane and matrix proteins are initially targeted to multiple vesicular precursors that represent intermediates in the assembly pathway of peroxisomes. The authors have also recently identified a novel cytosolic chaperone, Pex20p, that assists in the oligomerization of thiolase in the cytosol and promotes its targeting to the peroxisome. These data provide the first evidence that a chaperone-assisted folding and oligomerization of thiolase in the cytosol is required for the import of this protein into the peroxisomal matrix.

Conserved vertebrate chromosome segments in the large salamander genome

Urodele amphibians (salamanders) are important models for embryological, physiological, and natural history research and are also a biomedically important group because they are the only vertebrates capable of regenerating entire organ systems. To enhance the utility of salamanders for biomedical research and for understanding genome evolution, genetic linkage analysis was used to identify chromosome segments that are homologous between ambystomatid salamanders and distantly related vertebrate model organisms. A total of 347 loci (AFLPs, RAPDs, and protein-coding loci) were mapped using an interspecific meiotic mapping panel (Ambystoma mexicanum and A. tigrinum tigrinum; family Ambystomatidae). Genome size in Ambystoma was estimated to be 7291 cM, the largest linkage map estimate reported for any organism. However, the relatively large size of the salamander genome did not hinder efforts to map and identify conserved syntenies from a small sample of 24 protein-coding loci. Chromosomal segments that are conserved between fishes and mammals are also conserved in these salamanders. Thus, comparative gene mapping appears to be an efficient strategy for identifying orthologous loci between ambystomatid salamanders and genomically well-characterized vertebrate model organisms.

Cardiologic problems in the post acute ventilated patient

Chronically critically ill patients who develop acute respiratory failure commonly have complicating cardiac pathology that may or may not be evident at initial evaluation. The acute coronary syndromes should be excluded in all patients presenting with respiratory failure. Cardiac rhythm disturbances are common and should be actively investigated and treated in all critically ill patients. Heart failure is common in the chronically critically ill patient but usually responds to early diagnosis and prompt treatment. Finally, cardiogenic shock carries a poor prognosis in most patient subsets except when it is caused by cardiac tamponade. The intensivist must be vigilant for cardiac pathology complicating the recovery of patients with acute respiratory illness and initiate the search for correctable problems that may precipitate further episodes of respiratory insufficiency.