Analysis of the anti-apoptotic activity of four vaccinia virus proteins demonstrates that B13 is the most potent inhibitor in isolation and during viral infection

Vaccinia virus (VACV) is a large dsDNA virus encoding ~200 proteins, several of which inhibit apoptosis. Here, a comparative study of anti-apoptotic proteins N1, F1, B13 and Golgi anti-apoptotic protein (GAAP) in isolation and during viral infection is presented. VACVs strains engineered to lack each gene separately still blocked apoptosis to some degree because of functional redundancy provided by the other anti-apoptotic proteins. To overcome this redundancy, we inserted each gene separately into a VACV strain (vv811) that lacked all these anti-apoptotic proteins and that induced apoptosis efficiently during infection. Each protein was also expressed in cells using lentivirus vectors. In isolation, each VACV protein showed anti-apoptotic activity in response to specific stimuli, as measured by immunoblotting for cleaved poly(ADP ribose) polymerase-1 and caspase-3 activation. Of the proteins tested, B13 was the most potent inhibitor, blocking both intrinsic and extrinsic stimuli, whilst the activity of the other proteins was largely restricted to inhibition of intrinsic stimuli. In addition, B13 and F1 were effective blockers of apoptosis induced by vv811 infection. Finally, whilst differences in induction of apoptosis were barely detectable during infection with VACV strain Western Reserve compared with derivative viruses lacking individual anti-apoptotic genes, several of these proteins reduced activation of caspase-3 during infection by vv811 strains expressing these proteins. These results illustrated that vv811 was a useful tool to determine the role of VACV proteins during infection and that whilst all of these proteins have some anti-apoptotic activity, B13 was the most potent.

hGAAP promotes cell adhesion and migration via the stimulation of store-operated Ca2+ entry and calpain 2

Golgi antiapoptotic proteins (GAAPs) are highly conserved Golgi membrane proteins that inhibit apoptosis and promote Ca(2+) release from intracellular stores. Given the role of Ca(2+) in controlling cell adhesion and motility, we hypothesized that human GAAP (hGAAP) might influence these events. In this paper, we present evidence that hGAAP increased cell adhesion, spreading, and migration in a manner that depended on the C-terminal domain of hGAAP. We show that hGAAP increased store-operated Ca(2+) entry and thereby the activity of calpain at newly forming protrusions. These hGAAP-dependent effects regulated focal adhesion dynamics and cell migration. Indeed, inhibition or knockdown of calpain 2 abrogated the effects of hGAAP on cell spreading and migration. Our data reveal that hGAAP is a novel regulator of focal adhesion dynamics, cell adhesion, and migration by controlling localized Ca(2+)-dependent activation of calpain.

Human and viral Golgi anti-apoptotic proteins (GAAPs) oligomerize via different mechanisms and monomeric GAAP inhibits apoptosis and modulates calcium

Golgi anti-apoptotic proteins (GAAPs) are hydrophobic proteins resident in membranes of the Golgi complex. They protect cells from a range of apoptotic stimuli, reduce the Ca²⁺ content of intracellular stores, and regulate Ca²⁺ fluxes. GAAP was discovered in camelpox virus, but it is highly conserved throughout evolution and encoded by all eukaryote genomes examined. GAAPs are part of the transmembrane Bax inhibitor-containing motif (TMBIM) family that also includes other anti-apoptotic and Ca²⁺-modulating membrane proteins. Most TMBIM members show multiple bands when analyzed by SDS-PAGE, suggesting that they may be oligomeric. However, the molecular mechanisms of oligomerization, the native state of GAAPs in living cells and the functional significance of oligomerization have not been addressed. TMBIM members are thought to have evolved from an ancestral GAAP. Two different GAAPs, human (h) and viral (v)GAAP were therefore selected as models to examine oligomerization of TMBIM family members. We show that both hGAAP and vGAAP in their native states form oligomers and that oligomerization is pH-dependent. Surprisingly, hGAAP and vGAAP do not share the same oligomerization mechanism. Oligomerization of hGAAP is independent of cysteines, but oligomerization of vGAAP depends on cysteines 9 and 60. A mutant vGAAP that is unable to oligomerize revealed that monomeric vGAAP retains both its anti-apoptotic function and its effect on intracellular Ca²⁺ stores. In conclusion, GAAP can oligomerize in a pH-regulated manner, and monomeric GAAP is functional.

Phase I trial of recombinant modified vaccinia ankara encoding Epstein-Barr viral tumor antigens in nasopharyngeal carcinoma patients

Epstein-Barr virus (EBV) is associated with several malignancies including nasopharyngeal carcinoma, a high incidence tumor in Chinese populations, in which tumor cells express the two EBV antigens EB nuclear antigen 1 (EBNA1) and latent membrane protein 2 (LMP2). Here, we report the phase I trial of a recombinant vaccinia virus, MVA-EL, which encodes an EBNA1/LMP2 fusion protein designed to boost T-cell immunity to these antigens. The vaccine was delivered to Hong Kong patients with nasopharyngeal carcinoma to determine a safe and immunogenic dose. The patients, all in remission more than 12 weeks after primary therapy, received three intradermal MVA-EL vaccinations at three weekly intervals, using five escalating dose levels between 5 × 10(7) and 5 × 10(8) plaque-forming unit (pfu). Blood samples were taken during prescreening, immediately before vaccination, one week afterward and at intervals up to one year later. Immunogenicity was tested by IFN-γ ELIspot assays using complete EBNA1 and LMP2 15-mer peptide mixes and known epitope peptides relevant to patient MHC type. Eighteen patients were treated, three per dose level one to four and six at the highest dose, without dose-limiting toxicity. T-cell responses to one or both vaccine antigens were increased in 15 of 18 patients and, in many cases, were mapped to known CD4 and CD8 epitopes in EBNA1 and/or LMP2. The range of these responses suggested a direct relationship with vaccine dose, with all six patients at the highest dose level giving strong EBNA1/LMP2 responses. We concluded that MVA-EL is both safe and immunogenic, allowing the highest dose to be forwarded to phase II studies examining clinical benefit.

Bioavailability of digoxin from rapidly dissolving preparations

1 Intestinal absorption of digoxin was assessed by determination of peak plasma concentrations, areas under plasma concentration curves over 80 h, and 10 day urinary excretion. Absorption was equal after ingestion of single doses of standard Lanoxin (Wellcome) tablets, tablets and capsules of ultra-rapid dissolution rate material, or an oral solution of digoxin in water. 2 Mean plasma concentrations and dosage-interval urinary excretion were highly similar during 14 day courses of either Lanoxin or ultra-rapid dissolution tablets. Increased bioavailability does not result from encapsulation of solid dosage presentations, nor from increasing tablet dissolution rate beyond 75% in 15 minutes. 3 Fourteen day courses of tablets of slow dissolution rate produced lower and less consistent mean plasma concentrations and urinary excretion. Slow dissolution rates are associated with greater individual variability in absorption.

Six-transmembrane topology for Golgi anti-apoptotic protein (GAAP) and Bax inhibitor 1 (BI-1) provides model for the transmembrane Bax inhibitor-containing motif (TMBIM) family

The Golgi anti-apoptotic protein (GAAP) is a hydrophobic Golgi protein that regulates intracellular calcium fluxes and apoptosis. GAAP is highly conserved throughout eukaryotes and some strains of vaccinia virus (VACV) and camelpox virus. Based on sequence, phylogeny, and hydrophobicity, GAAPs were classified within the transmembrane Bax inhibitor-containing motif (TMBIM) family. TMBIM members are anti-apoptotic and were predicted to have seven-transmembrane domains (TMDs). However, topology prediction programs are inconsistent and predicted that GAAP and other TMBIM members have six or seven TMDs. To address this discrepancy, we mapped the transmembrane topology of viral (vGAAP) and human (hGAAP), as well as Bax inhibitor (BI-1). Data presented show a six-, not seven-, transmembrane topology for vGAAP with a putative reentrant loop at the C terminus and both termini located in the cytosol. We find that this topology is also conserved in hGAAP and BI-1. This places the charged C terminus in the cytosol, and mutation of these charged residues in hGAAP ablated its anti-apoptotic function. Given the highly conserved hydrophobicity profile within the TMBIM family and recent phylogenetic data indicating that a GAAP-like protein may have been the ancestral progenitor of a subset of the TMBIM family, we propose that this vGAAP topology may be used as a model for the remainder of the TMBIM family of proteins. The topology described provides valuable information on the structure and function of an important but poorly understood family of proteins.

Fatal cases of influenza A(H3N2) in children: insights from whole genome sequence analysis

During the Northern Hemisphere winter of 2003–2004 the emergence of a novel influenza antigenic variant, A/Fujian/411/2002-like(H3N2), was associated with an unusually high number of fatalities in children. Seventeen fatal cases in the UK were laboratory confirmed for Fujian/411-like viruses. To look for phylogenetic patterns and genetic markers that might be associated with increased virulence, sequencing and phylogenetic analysis of the whole genomes of 63 viruses isolated from fatal cases and non fatal “control” cases was undertaken. The analysis revealed the circulation of two main genetic groups, I and II, both of which contained viruses from fatal cases. No associated amino acid substitutions could be linked with an exclusive or higher occurrence in fatal cases. The Fujian/411-like viruses in genetic groups I and II completely displaced other A(H3N2) viruses, but they disappeared after 2004. This study shows that two A(H3N2) virus genotypes circulated exclusively during the winter of 2003–2004 in the UK and caused an unusually high number of deaths in children. Host factors related to immune state and differences in genetic background between patients may also play important roles in determining the outcome of an influenza infection.

Serological responses in humans to the smallpox vaccine LC16m8

In response to potential bioterrorism with smallpox, members of the Japanese Self-Defense Forces were vaccinated with vaccinia virus (VACV) strain LC16m8, an attenuated smallpox vaccine derived from VACV strain Lister. The serological response induced by LC16m8 to four virion-surface proteins and the intracellular mature virus (IMV) and extracellular enveloped virus (EEV) was investigated. LC16m8 induced antibody response against the IMV protein A27 and the EEV protein A56. LC16m8 also induced IMV-neutralizing antibodies, but unlike the VACV strain Lister, did not induce either EEV-neutralizing antibody or antibody to EEV protein B5, except after revaccination. Given that B5 is the only target for EEV-neutralizing antibody and that neutralization of both IMV and EEV give optimal protection against orthopoxvirus challenge, these data suggest that immunity induced by LC16m8 might be less potent than that deriving from strain Lister. This potential disadvantage should be balanced against the advantage of the greater safety of LC16m8.

Relationship Between Substrate Concentration and Fermentation Product Ratios in Clostridium thermocellum Cultures

Growth of Clostridium thermocellum in batch cultures was studied over a broad range of cellobiose concentrations. Cultures displayed important differences in their substrate metabolism as determined by the end product yields. Bacterial growth was severely limited when the initial cellobiose concentration was 0.2 (wt/vol), was maximal at substrate concentrations between 0.5 and 2.0%, and did not occur at 5.0% cellobiose. Ethanol accumulated maximally (38.3 mumol/10 cells) in cultures with an initial cellobiose concentration of 0.8%, whereas cultures in 2.0% cellobiose accumulated only 17.3 mumol, and substrate-limited cultures (0.2% cellobiose) accumulated little, if any, ethanol beyond that initially detected (8.3 mumol/10 cells). In a medium with 0.8% cellobiose, ethanol was produced at a constant rate of approximately 1.1 mumol/10 cells per h from late-logarithmic phase (16 h) of growth well into stationary phase (44 h). When ethanol was added exogenously at levels more than twice the maximum produced by the cultures themselves (0.5% [vol/vol]), neither the extent of growth (maximum Klett units, 150) nor the amounts of ethanol produced ( approximately 0.17%) by the culture was affected. The ratio of ethanol to acetate was highest (2.8) when cells were grown in 0.8% cellobiose and lowest (1.2) when cells were grown in 0.2% cellobiose.

Fatal cases of influenza a in childhood

BACKGROUND

In the northern hemisphere winter of 2003-04 antigenic variant strains (A/Fujian/411/02 -like) of influenza A H3N2 emerged. Circulation of these strains in the UK was accompanied by an unusually high number of laboratory confirmed influenza associated fatalities in children. This study was carried out to better understand risk factors associated with fatal cases of influenza in children.

METHODOLOGY/PRINCIPAL FINDINGS

Case histories, autopsy reports and death registration certificates for seventeen fatal cases of laboratory confirmed influenza in children were analyzed. None had a recognized pre-existing risk factor for severe influenza and none had been vaccinated. Three cases had evidence of significant bacterial co-infection. Influenza strains recovered from fatal cases were antigenically similar to those circulating in the community. A comparison of protective antibody titres in age stratified cohort sera taken before and after winter 2003-04 showed that young children had the highest attack rate during this season (21% difference, 95% confidence interval from 0.09 to 0.33, p = 0.0009). Clinical incidences of influenza-like illness (ILI) in young age groups were shown to be highest only in the years when novel antigenic drift variants emerged.

CONCLUSIONS/SIGNIFICANCE

This work presents a rare insight into fatal influenza H3N2 in healthy children. It confirms that circulating seasonal influenza A H3N2 strains can cause severe disease and death in children in the apparent absence of associated bacterial infection or predisposing risk factors. This adds to the body of evidence demonstrating the burden of severe illness due to seasonal influenza A in childhood.

Vascular endothelial growth factor and immunosuppression in cancer: current knowledge and potential for new therapy

Two decades of research into the role of immunosuppression and angiogenesis in tumor biology have revealed multiple links between the two. Vascular endothelial growth factor, originally thought to be solely involved in vascular growth and permeability, has emerged as a significant agent of immune tolerance in the tumor microenvironment. This review examines two major elements of this field: the research behind the role of vascular endothelial growth factor in immunosuppression, especially as pertains to dendritic cell function; and the subsequent research into the potential for using antiangiogenic therapy to both starve tumors by hypoxia and enhance the response of tumors to immunotherapy. Several strategies tested so far have yielded incomplete, yet promising, results.

The effect of forefoot varus on postural stability

STUDY DESIGN

Counterbalanced experimental design study comparing a group of subjects with greater than or equal to 70 of forefoot varus (MFV) to a group with less than 70 of forefoot varus (LFV).

OBJECTIVES

To investigate the effect of forefoot varus on single-limb stance postural stability (PS).

BACKGROUND

Impaired PS has been implicated as a potential risk factor for sustaining acute foot and ankle injuries. The identification of variables that deleteriously affect PS may be important in the prevention of future injuries.

METHODS AND MEASURES

Postural stability of the MFV group (n = 20) and the LFV group (n = 12) was assessed during right and left single-limb stance and eyes-open and eyes-closed conditions. Standard deviations of the x-axis and y-axis ground reaction forces measured via a force platform were used to represent anteroposterior (AP) and mediolateral (ML) PS, respectively. The mean of 3 successful 5-second trials of each testing condition was calculated and used for subsequent data analysis using 3-way mixed-model ANOVAs with 1 between-subject and 2 within-subject factors.

RESULTS

The AP PS scores of the MFV group were significantly greater than those of the LFV group (P < .05). ML PS scores, although higher in the MFV group, were not significantly different from those of the LFV group. Both groups had significantly greater AP and ML PS scores during the eyes-closed versus the eyes-open condition (P < .05).

CONCLUSIONS

The results suggest that the presence of greater than or equal to 70 of forefoot varus may significantly impair AP PS. The decreased stability associated with increased forefoot varus may be due to decreased joint congruity and consequently an increased reliance on soft tissue structures for stability.

The role of hyperbaric oxygen therapy in ischaemic diabetic lower extremity ulcers: a double-blind randomised-controlled trial

OBJECTIVE

ischaemic lower-extremity ulcers in the diabetic population are a source of major concern because of the associated high risk of limb-threatening complications. The aim of this study was to evaluate the role of hyperbaric oxygen in the management of these ulcers.

METHOD

eighteen diabetic patients with ischaemic, non-healing lower-extremity ulcers were recruited in a double-blind study. Patients were randomly assigned either to receive 100% oxygen (treatment group) or air (control group), at 2.4 atmospheres of absolute pressure for 90 min daily (total of 30 treatments).

RESULTS

healing with complete epithelialisation was achieved in five out of eight ulcers in the treatment group compared to one out of eight ulcers in the control group. The median decrease of the wound areas in the treatment group was 100% and in the control group was 52% (p=0.027). Cost-effectiveness analysis has shown that despite the extra cost involved in using hyperbaric oxygen, there was a potential saving in the total cost of treatment for each patient during the study.

CONCLUSION

hyperbaric oxygen enhanced the healing of ischaemic, non-healing diabetic leg ulcers and may be used as a valuable adjunct to conventional therapy when reconstructive surgery is not possible.

Risk modelling for carotid endarterectomy

Background

A 30-day stroke or death rate of 3–10 per cent has been reported in patients undergoing carotid endarterectomy (CEA). The aim of this study was to identify the risk factors that influenced the outcome and to develop a logistic regression model that can aid in the comparative audit of CEA.

Methods

Some 836 CEAs performed by four vascular surgeons from 1992 to 1999 were analysed. The median age of the population was 69 (range 38–86) years, and the male: female ratio was 1·6. Multiple logistic regression was used to model the effect of 15 risk factors on the 30-day stroke and death rate. The outcome after risk adjustment was compared for four surgeons and two vascular units.

Results

The overall 30-day stroke and death rate was 3·9 per cent. Regression modelling identified heart disease, diabetes and stroke at presentation as significant risk factors. A risk score of 1 was assigned to each of these risk factors to produce a logistic regression equation (where P is the probability of 30-day stroke or death):

ln(P/1 − P) = 0·9294(risk score) − 4·2726.

The observed 30-day stroke and death rate for four vascular surgeons was 3·0, 4·0, 4·2 and 4·3, and for two vascular units was 3·9 and 3·9. Differences between the surgeons and the vascular units were not statistically significant after allowing for risk adjustment using this model.

Conclusion

Multiple logistic regression models can successfully identify patients at higher risk from CEA, and aid in the comparative audit of surgeons and vascular units.

POSSUM and P-POSSUM overpredict mortality for carotid endarterectomy

OBJECTIVES

the aim was to test the predictive accuracy of POSSUM and P-POSSUM on patients undergoing CEA.

DESIGN

retrospective and prospective study.

MATERIALS

499 CEAs performed by four vascular surgeons from a single unit from 1992-99. The median age was 68 (range 38-86) and 60% were men.

METHODS

physiological parameters, operative parameters and the 30-day mortality were collected. Predicted mortality for each patient was calculated using POSSUM and P-POSSUM equations. Patients were stratified into risk groups and observed and predicted deaths were compared. Accuracy of the prediction was assessed using chi-squared analysis.

RESULTS

the observed 30-day mortality was 1.8% (9/499). The predicted deaths using POSSUM and P-POSSUM analysis were 49 and 25 respectively compared to nine observed deaths. There was significant evidence of lack of fit of both models in predicting mortality (chi-squared analysis, p<0.05).

CONCLUSIONS

POSSUM and P-POSSUM overpredict mortality and are unsuitable for comparative audit of CEA. Models developed specific for CEA might accurately predict mortality.

Risk modelling study for carotid endarterectomy

BACKGROUND

The aims of this study were to identify factors that influence the risk of stroke or death following carotid endarterectomy (CEA) and to develop a model to aid in comparative audit of vascular surgeons and units.

METHODS

A series of 839 CEAs performed by four vascular surgeons between 1992 and 1999 was analysed. Multiple logistic regression analysis was used to model the effect of 15 possible risk factors on the 30-day risk of stroke or death. Outcome was compared for four surgeons and two units after adjustment for the significant risk factors.

RESULTS

The overall 30-day stroke or death rate was 3.9 per cent (29 of 741). Heart disease, diabetes and stroke were significant risk factors. The 30-day predicted stroke or death rates increased with increasing risk scores. The observed 30-day stroke or death rate was 3.9 per cent for both vascular units and varied from 3.0 to 4.2 per cent for the four vascular surgeons. Differences in the outcomes between the surgeons and vascular units did not reach statistical significance after risk adjustment.

CONCLUSION

Diabetes, heart disease and stroke are significant risk factors for stroke or death following CEA. The risk score model identified patients at higher risk and aided in comparative audit.

Transient kinetic and dynamic interactions between verapamil and dofetilide, a class III antiarrhythmic

Potential kinetic and dynamic interactions between the new class III antiarrhythmic dofetilide (D) and the calcium channel blocker verapamil (V) were determined in 12 young healthy male volunteers. A fixed sequence of V80 mg tid, placebo, D 0.5 mg bid, and D + V was given as matching active and placebo capsules. In steady-state conditions during combination treatment, a modest increase in mean (+/- SD) peak plasma concentration of dofetilide from 2.40 +/- 0.42 to 3.43 +/- 0.71 ng x ml(-1) (43% increase, p < 0.1) was noted. During the combination period, for the first 4 hours, mean AUC values for D increased from 7.4 +/- 1.0 (D alone) to 9.2 +/- 1.4 ng x h x ml(-1) (26% increase, p <0.1). No other significant pharmacokinetic interaction was seen. These transient changes were concurrent with trends for a dynamic interaction. The maximal mean increase in QT, over steady-state baseline values was 20 msec for D alone versus 26 msec during combination therapy. This relatively small interactive effect occurred only while peak plasma drug concentrations were developing at 1 to 3 hours after dosing and is probably caused by the known effect of verapamil to increase hepatic and portal bloodflow. In view of this interaction and the relationship between dofetilide plasma concentration and torsade, verapamil is contraindicated in patients receiving dofetilide.

NMR studies of Ru(3)(CO)(10)(PMe(2)Ph)(2) and Ru(3)(CO)(10)(PPh(3))(2) and their H(2) addition products: detection of new isomers with complex dynamic behavior

The clusters Ru(3)(CO)(10)L(2), where L = PMe(2)Ph or PPh(3), are shown by NMR spectroscopy to exist in solution in at least three isomeric forms, one with both phosphines in the equatorial plane on the same ruthenium center and the others with phosphines in the equatorial plane on different ruthenium centers. Isomer interconversion for Ru(3)(CO)(10)(PMe(2)Ph)(2) is highly solvent dependent, with DeltaH decreasing and DeltaS becoming more negative as the polarity of the solvent increases. The stabilities of the isomers and their rates of interconversion depend on the phosphine ligand. A mechanism that accounts for isomer interchange involving Ru-Ru bond heterolysis is suggested. The products of the reaction of Ru(3)(CO)(10)L(2) with hydrogen have been monitored by NMR spectroscopy via normal and para hydrogen-enhanced methods. Two hydrogen addition products are observed with each containing one bridging and one terminal hydride ligand. EXSY spectroscopy reveals that both intra- and interisomer hydride exchange occurs on the NMR time scale. On the basis of the evidence available, mechanisms for hydride interchange involving Ru-Ru bond heterolysis and CO loss are proposed.

Solvent-free routes to clean technology

A major aim for the chemical technology of the future is the avoidance of noxious and environmentally unacceptable organic solvents. In this concept article we discuss more environmentally friendly and highly selective alternatives which we have evolved for carrying out a number of important chemical conversions. These entail the use of porous heterogeneous catalysts in which the active sites have been atomically engineered and fully characterized. Such solid catalysts operate under solvent-free conditions and usually entail one-step processes.

A design for testing interventions to improve adherence within a hypertension clinical trial

The Potassium Adherence Clinical Trial (PACT) incorporates one randomized clinical trial within another. A randomized trial of interventions to increase adherence to medication is nested within a second randomized clinical trial testing hypotensive effect of supplemental oral potassium. The trial aims principally to compare the effects of three intervention strategies: two sessions of individual patient counseling, two telephone contacts, or standard care. The trial aims secondarily to evaluate the effect of 60 mEq supplemental oral potassium daily on sitting systolic and diastolic blood pressure in hypertensive patients on established drug therapy. Therefore, it organizes the patients given potassium into three study groups for adherence interventions, and the patients assigned to placebo into a further three. We evaluate adherence primarily by means of the Medication Event Monitoring System (MEMS), an electronic system that records the date and time that the container of study medication is opened. Additional measurements, such as assessments of change in levels of urinary potassium, pill counts, appointment records, self-reporting by patients, and estimates by physician of adherence, are used and correlated with MEMS data. At a single center, the trial enrolled 107 participants between the ages of 26 and 80. This paper describes the background to this trial within a trial, details its design, documents the baseline characteristics of participants enrolled, and describes issues experienced during implementation of the trial.

Energy-dependent electrospray ionisation mass spectrometry: applications in transition metal carbonyl chemistry

Maps of electrospray mass spectrometry data, plotted as cone voltage versus mass-to-charge ratio, provide a clear and compact method of visualising the accompanying fragmentation processes, in this case applied to the sequential removal of ligands from transition-metal carbonyl complexes. The technique is described as energy-dependent electrospray ionisation mass spectrometry (EDESI-MS). Copyright 2000 John Wiley & Sons, Ltd.

A biomechanical evaluation of visually impaired persons' gait and long-cane mechanics

This study was designed to compare selected kinematic components of gait and long cane mechanics between groups of visually impaired travelers. Twenty subjects were placed in Traditional or Modified technique groups according to their long cane traveling technique. Subjects were measured during the following conditions; 1) normal walking (NW), 2) walking while anticipating a simulated drop-off (AD), 3) walking while responding to an audible task (ST) and, 4) walking while anticipating a simulated drop-off and responding to an audible task (STAD). Data were analyzed using a repeated measures analysis of variance (ANOVA) and Pearson's r correlation coefficient. Analyses revealed no differences between groups of travelers. However, significant differences were noted between trials for components of gait velocity, stride length, and hip flexion velocity. These findings may indicate a potentially dangerous alteration in the normal gait cycle of visually impaired travelers when faced with additional attention-demanding tasks while walking.

Randomized prospective comparison of laparoscopic and open peritoneal dialysis catheter insertion

OBJECTIVE

To compare laparoscopic and conventional peritoneal dialysis catheter insertion with respect to post operative discomfort, complication rates, and catheter survival.

DESIGN

Randomized prospective study.

SETTING

Tertiary referral renal unit.

PATIENTS

Fifty patients commencing peritoneal dialysis.

INTERVENTION

Catheters were implanted laparoscopically or by a conventional surgical technique.

MAIN OUTCOME MEASURES

The duration of surgery, hospital stay, pain scores, and analgesic requirements were recorded. Complications (early/late) and catheter survival were compared.

RESULTS

The conventional procedure was faster than the laparoscopic (14.3 vs 21.9 minutes, p < 0.0001). There was no difference in any other parameter assessed.

CONCLUSIONS

The data suggest that the insertion techniques are equivalent, and that laparoscopic insertion does not reduce early complication rates.

Assessment of anteroposterior instability of the knee during gait

A noninvasive kinematic recording technique involving geometric modeling of the knee joint was employed to determine anteroposterior displacements of the knee during walking. The model estimated how much the femoral condyles slid and rolled on the tibial plateau. Movement not due to sliding or rolling was attributed to horizontal translation of the tibia with respect to the femur. Thirty normal adults participated in this study. A three-dimensional analysis system with noninvasive skin markers was employed to collect kinematic data of the femur and tibia during walking. Within-session and between-session reliabilities were high in the tested subjects. Normal subjects had an average of 5.5 mm of maximum anterior displacement of the tibia during stance phase of walking. These results differed neither between left and right knees, nor between men and women. Dynamic instability of the knee during walking can be reasonably measured by the proposed method in normal subjects.

Ruptured fission yeast walls. Structural discontinuities related to the cell cycle

Distributions of rupture sites of fission yeast cells ruptured by glass beads have been related to a new morphometric analysis. As shown previously (Johnson et al., Cell Biophysics, 1995), ruptures were not randomly distributed nor was their distribution dictated by geometry, rather, ruptures at the extensile end were related to cell length just as the rate of extension is related to cell length. The extension patterns of early log, mid-log, late log, and stationary phase cells from suspension cultures were found to approximate the linear growth patterns of Kubitschek and Clay (1986). The median length of cells was found to decline through the log phase in an unbalanced manner.

Gait and long cane kinematics: a comparison of sighted and visually impaired subjects

Although visually impaired individuals have used the long cane to increase mobility for many years, few empirical studies have examined the effectiveness of this tool. The purposes of this research were to determine if these cane procedures provide adequate protection for visually impaired individuals and to compare sighted and visually impaired gait mechanics. Seven sighted (four females, three males) and five visually impaired subjects (two females, three males) were videotaped at 60 Hz by two cameras situated at opposite 45 degrees angles to the subjects' frontal plane so that three-dimensional coordinates could be calculated via direct linear transformation. One-way analyses of variance were calculated on 17 variables to determine if there was a significant biomechanical difference between sighted and visually impaired gait at an adjusted alpha = .003. The results showed that for both groups the cane tip touched outside where the foot landed and that the only variable significantly different between the two groups was resultant cane velocity. The major conclusion of this research was that present cane techniques may not provide adequate protection for visually impaired individuals since the purpose of mobility training is to have the person touch the ground with the cane tip at the foot contact positions.

A prospective study of the effect of limb-threatening ischaemia and its surgical treatment on the quality of life

OBJECTIVE

To assess the quality of life after treatment for limb-threatening ischaemia.

DESIGN

An open, prospective, observational study in a Vascular Unit of a University Hospital.

MATERIALS

One hundred and fifty consecutive patients presenting with actual or threatened tissue loss of the leg.

METHODS

A single, experienced observer assessed the patients for pain, mobility, anxiety, depression, self-care and lifestyle at presentation, 6 and 12 months later.

RESULTS

Six different treatment outcomes were recognised: successful angioplasty, successful thrombolysis/thrombectomy, successful surgical bypass, amputation after failed revascularisation, primary unilateral amputation and primary bilateral amputation. Pain was significantly improved in all groups (p < 0.05) except for patients after failed revascularization (p = 0.08). Mobility improved in patients who underwent angioplasty (p = 0.05) or a successful surgical bypass (p = 0.001). Anxiety and depression both improved significantly only after surgical reconstruction (p < 0.02). Self-care ability improved significantly after angioplasty (p < 0.05), surgical reconstruction (p < 0.005) and unilateral primary amputation (p < 0.05), but was unaltered in the other groups. Lifestyle significantly deteriorated following thrombolysis/thrombectomy and failed surgical reconstruction (p < 0.05), but was maintained in all other groups.

CONCLUSIONS

The treatment of limb-threatening ischaemia should aim to maintain pre-morbid lifestyle, an aim which is best achieved by limb-salvage. The patient's own expectations and needs have a major bearing on the choice of therapy.

Sexual co-flocculation by heterothallic cells of the fission yeast Schizosaccharomyces pombe modulated by medium constituents

Novel simple synthetic media for inducing sexual co-flocculation in a short time after mixing heterothallic fission-yeast (Schizosaccharomyces pombe) cells of h- and h+ were devised; The most effective of these, mannose synthetic medium (MSM), contains 0.4% mannose as a carbon source in addition to galactose, KH2PO4 (pH4.0) and 4 vitamins. The addition of galactose to the medium suppressed the asexual self-flocculation but rather promoted the sexual co-flocculation. By transferring and mixing h- and h+ cells grown in malt-extract broth plus galactose into MSM, these heterothallic strains were revealed to be sexually ready through a long period of the log to stationary phases. Furthermore, a variety of C sources and NH4Cl at various concentrations in various media were examined for their effects upon sexual co-flocculation, conjugation and sporulation; it was found that the sugar concentration strictly affected the progress of the sequence of sexual reproduction at 26 degrees C but not 30 degrees C and that sexual co-flocculation of the heterothallic strains was induced only under lower concentrations of C and N source than that for the homothallic one.

The site of residual abnormalities in the leg veins in long-term follow-up after deep vein thrombosis and their relationship to the development of the post-thrombotic syndrome

Two major sequelae of deep vein thrombosis (DVT), obstruction to outflow due to the presence of residual thrombus and reflux due to valvular damage, may contribute to the development of the post-thrombotic syndrome (PTS). We studied the nature and site of residual abnormality, non-invasively with duplex ultrasound, in the veins of 69 limbs in 66 patients, 1 to 6 years after primary acute DVT. There were clinical features of the PTS in 27 limbs and 42 legs were asymptomatic. The pattern of duplex abnormalities was complex and varied for both the PTS and asymptomatic groups. The proportion of abnormal common and external iliac veins and abnormal common, deep and superficial femoral veins was similar for limbs with the PTS and asymptomatic limbs. Twenty-six per cent of legs with the PTS had reflux at the saphenofemoral junction compared with 19% asymptomatic legs (difference not significant). The PTS was associated with proportionally more abnormal popliteal veins (81% vs 55%) and posterior tibial veins (PTV), PTV#1 (41% vs 21%) and PTV#2 (41% vs 14%) when compared with asymptomatic limbs. The odds ratio for a popliteal vein abnormality being associated with the PTS was 3.63 (95% CI 1.16 to 11.43). The odds ratios for PTV#1 and PTV#2 abnormalities in association with the PTS compared to asymptomatic limbs were 2.52 (95% CI 0.87 to 7.31) and 4.13 (95% CI 1.30 to 13.11). In conclusion, residual venous abnormalities after DVT are common and when present in the popliteal and tibial veins are associated with an increased likelihood of PTS expression.

Contribution to the biophysics of the lethal effects of electric field on microorganisms

The proposed model assumes that the criteria leading to the lethal breakdown of microorganisms suspended in a continuous medium depend on two parameters: (a) the applied electric field must exceed the critical field of membrane to create holes and (b) the Joule energy (deposited in the membrane) must exceed the minimum value beyond which the cell can not recover. The first parameter initiates (reversible) breakdown and the second one, the completion of the (irreversible) electrical breakdown leading to death of the cell. The number of cells surviving the electric field treatment is related to statistical distribution of cell size. Comparison between theory and the experimental results of Kinosita and Tsong (1977); Hülsheger et al. (1980, 1981, 1983); Rosemberg and Korenstein (1990) and others is given.

Differential effects of glucocorticoids on insulin-like growth factor I action in cultured human fibroblasts

Glucocorticoids act synergistically with insulin-like growth factor I (IGF-I) to stimulate DNA synthesis and replication of cultured human fibroblasts. In the present study, we further define glucocorticoid and IGF-I interactive effects on human fibroblast metabolism and growth. IGF-I stimulated dose-dependent increases in early metabolic events. Half-maximal effectiveness was seen at 5-8 ng/ml IGF-I, with mean maximal responses of 1.5-, 2-, and 6-fold for [3H]2-deoxyglucose uptake, [14C]glucose incorporation, and [14C]aminoisobutyric acid (AIB) uptake, respectively. A 48-hour preincubation with 10(-7) M dexamethasone markedly enhanced both the sensitivity and maximal effectiveness of IGF-I stimulation of AIB uptake. In contrast, dexamethasone had no effect on IGF-I-stimulated glucose uptake and utilization. Maximum specific binding of [125I]IGF-I to fibroblast monolayers was identical in ethanol control and glucocorticoid-treated cells, with 50% displacement at approximately 5 ng/ml IGF-I. In addition to its synergism with IGF-I, preincubation with dexamethasone augmented insulin and epidermal growth factor (EGF) stimulation of [3H]thymidine incorporation; dexamethasone had no effect on platelet-derived growth factor or fibroblast growth factor action. Two-dimensional gel electrophoresis identified two specific glucocorticoid-induced proteins in human fibroblast cell extracts with molecular weights of 45K and 53K and pIs of 6.8 and 6.3, respectively. These data indicate that IGF-I receptor-mediated actions in human fibroblasts are differentially modulated by glucocorticoids. Glucocorticoids are synergistic with IGF-I in stimulating mitogenesis and amino acid uptake, without having any apparent effect on IGF-I-stimulating glucose metabolism. Glucocorticoid enhancement of growth factor bioactivity may involve modulation of a regulatory event in the mitogenic signaling pathway subsequent to cell surface receptor activation.

A multicenter comparison of adverse reaction profiles of isradipine and enalapril at equipotent doses in patients with essential hypertension

A multicenter, randomized, double-blind trial compared the safety and efficacy of the dihydropyridine isradipine with the angiotensin-converting enzyme (ACE) inhibitor enalapril given twice daily for mild hypertension. 160 patients received either isradipine (starting at 1.25 mg twice daily) or enalapril (starting at 2.5 mg twice daily) for 10 weeks. The dosage was increased if the average sitting diastolic blood pressure was > 90 mm Hg. Significantly greater mean reductions in systolic blood pressure were seen after 2, 6, and 8 weeks of isradipine. However, by the end of the trial, 83% of patients receiving isradipine and 78% receiving enalapril showed a decrease of at least 5 mm Hg in sitting diastolic blood pressure to a level below 96 mm Hg. Possible or probable drug-related adverse effects were reported in 36% of patients showing a good antihypertensive response to isradipine, and in 30% of those who responded to enalapril. There was a trend for a lower frequency of adverse effects in isradipine non-responders (25%) and a higher frequency in enalapril non-responders (43%). Pruritus, dizziness, edema, and fatigue were reported more often with isradipine, and cough and changed bowel habits were more common with enalapril. The relationship between the pattern of adverse effects and the extent of blood pressure reduction may be dependent on the mechanism of action of a drug. In responders, isradipine and enalapril showed differing patterns, but a similar overall incidence of adverse effects.

Relationship between changes in the deep venous system and the development of the postthrombotic syndrome after an acute episode of lower limb deep vein thrombosis: a one- to six-year follow-up

PURPOSE

This study investigated changes in the deep venous system and the development of the postthrombotic syndrome (PTS) after an episode of acute deep vein thrombosis (DVT).

METHODS

Seventy-eight patients (41 male patients, 37 female patients) with acute DVT in 83 legs (31 right, 42 left, five bilateral) underwent annual follow-up examinations for 1 to 6 years (median, 3 years) for symptoms and signs of the PTS. A venous duplex scan was performed at each visit to detect obstruction and reflux in the veins, both of which may contribute to the development of the PTS. DVT was primary in 69 limbs and recurrent in 14 limbs.

RESULTS

When last examined 49 limbs were free of symptoms, and 34 had the PTS (23 edema only, 11 hyperpigmentation). Only two patients had ulcers during the follow-up period; both patients had the ulcers in areas of hyperpigmentation in limbs with recurrent DVT. The extent of disease was similar in limbs with the PTS (79% multisegment, 18% single segment) and those without the PTS (69% multisegment, 12% single segment). In limbs with the PTS the deep veins were normal in only one (3%), six (18%) showed reflux only, five (15%) obstruction only, and 22 had features of both obstruction and reflux (65%). In limbs without the PTS the deep veins showed no abnormality in nine (18%), reflux only in 17 (35%), obstruction only in six (12%), and reflux with obstruction in 17 (35%). In the 11 limbs with hyperpigmentation nine had obstruction and reflux noted, one had obstruction only, and one had reflux alone.

CONCLUSIONS

After an episode of acute DVT 12% of the limbs returned to normal by duplex criteria. Although only 13% developed skin complications, 41% had features of the PTS. Limbs with the PTS had more than three times the odds of having combined reflux and obstruction than did limbs without the PTS (odds ratio = 3.5, 0.95 confidence intervals = 1.4, 8.6). Continued study of these patients will determine the course of those limbs with venous abnormalities that have not yet developed symptoms and signs of the PTS.

Smashed fission yeast walls. Structural discontinuities related to wall growth

Twenty-three samples of fission yeast cells (Schizosaccharomyces pombe) were smashed by shaking them with glass beads. The samples represented all phases of the culture cycle, with the lag and log phases emphasized. Ruptured walls of the smashed cells were observed by phase-contrast and electron microscopy. Ruptures were tabulated with respect to their magnitudes and locations. Ruptures occurred not at random, nor at sites directed by geometry, but predominated in certain definable wall regions. These discontinuities were correlated with morphogenetic activities of the cell. Thus, the extensile end was found to be most fragile through most of the culture cycle. Also fragile was the nonextensile end, its edge more than its middle. Further, the data were applied to the testing of predictions from extant models (Johnson endohydrolytic softening model and Wessels presoftened-posthardened and crosslinking model) for hyphal tip extension. The frequency of rupture at the extensile (old) end of the cell was qualitatively predicted by both models; the frequency at the nonextensile (new) end was not predictable by either. Rupture frequencies and characteristics at other regions conformed to predictions by one or the other model, but rarely by both.

Surgery for limb threatening ischaemia: a reappraisal of the costs and benefits

OBJECTIVES

To study the quality of life of patients following surgery for critical limb is ischaemia.

DESIGN

Part retrospective, part prospective open study.

SETTING

Vascular unit of a University Hospital.

MATERIALS

Seventy-nine consecutive patients, medium age 75 years (range 44 to 94), who presented with leg threatening ischaemia and who underwent successful revascularisation or a major amputation were studied.

CHIEF OUTCOME MEASURES

Six separate quality of life measures were recorded at 6 months: pain, mobility, anxiety, depression, activities of daily living (Barthel) and lifestyle (Frenchay).

MAIN RESULTS

The mortality of this group of patients after six months was 24%. Forty-seven patients were available for quality of life assessment six months after initial intervention. Overall, amputation was more costly than successful revascularisation and limb salvage. Limb salvage resulted in greater mobility (p < 0.001) and better performance in self-care (p < 0.001) and lifestyle (p = 0.006), but produced more anxiety and depression (p = 0.04) than major amputation. A subgroup of patients who had major amputation after a failed limb salvage operation consumed a disproportionate amount of resources and, although their mobility was typical of amputees, their self-care and lifestyle scores were similar to those who had successful limb salvage. OBSTRUCTIONS: Limb salvage is attempted in up to 22% of patients for whom primary amputation may provide more expeditious rehabilitation with minimal impairment of their lifestyle performance.

Clinical outcome in patients with mild and moderate carotid artery stenosis

PURPOSE

The natural history of incidentally discovered asymptomatic mild (< 50%) and moderate (50% to 79%) carotid artery stenosis is not known. The carotid artery duplex ultrasound surveillance program at the University of Washington Department of Vascular Surgery has serially evaluated patients with carotid artery disease for more than a decade and provides data on the progress and management of this disease.

METHODS

Patients with asymptomatic carotid artery bruits who had carotid artery disease causing less than 80% lumen diameter narrowing at their initial visit were identified. At each return visit (6 months, 1 year, and annually thereafter) a clinical questionnaire was completed, and bilateral carotid artery duplex sonography was performed.

RESULTS

Two hundred thirty-two patients (136 men and 96 women) were monitored for up to 10 years with sufficient data for a 7-year life-table analysis. Progression in the degree of stenosis was noted in 23% of patients during follow-up, and nearly half of these progressed to severe stenosis (80% to 99%) or occlusion. The risk of progression to severe stenosis and occlusion was significantly greater for those patients with moderate initial stenosis than mild initial stenosis (p < 0.01). The cumulative stroke risk for patients with mild initial stenosis (6%) was half of that for patients with moderate initial stenosis (11%) after 7 years. Carotid endarterectomy was performed in 27 patients during follow-up; in 13 the indication was an event ipsilateral to the stenosis, and in 14 there was asymptomatic progression to high-grade stenosis.

CONCLUSIONS

Regular monitoring of mild to moderate carotid artery stenosis shows how these lesions progress over time, permitting a realistic appraisal of their potential for producing an ischemic cerebrovascular event.

Plaque assay and replication of Tipula iridescent virus in Spodoptera frugiperda ovarian cells

A plaque assay was developed for the study of Tipula iridescent virus (TIV) replication using a cell line derived from the fall army worm Spodoptera frugiperda (Sf9). Infection and plaque formation were monitored with time by phase contrast microscopy, video and fluorescent light microscopy. Structure of virions, viroplasmic centres and organelles of infected cells were examined by transmission electron microscopy (TEM). After 4 h postinfection, plaques were visibly detected within the cell monolayer by the presence of localized cell damage and production of numerous vesicular-like cytoplasmic structures. Quantitation of virions present per A260 unit of TIV preparation was determined by TEM. The number of visible plaques corresponded to virus concentration and 1 A260 produced approximately 10(5) plaques. DNA hybridization analysis revealed no gross differences in genomic DNA from TIV propagated in either Sf9 cells or wax moth Galleria mellonella larvae. These findings indicate that Sf9 is permissive for replication of TIV and superior by some parameters to other cell lines currently in use for the study of host cell/TIV interactions.

Low-dose combined therapy with fluvastatin and cholestyramine in hyperlipidemic patients

OBJECTIVE

To compare the low-density lipoprotein (LDL) cholesterol-lowering efficacy of low-dose combinations of cholestyramine and fluvastatin.

DESIGN

Randomized, double-blind, parallel group, placebo-controlled trial with a 24-week double-blind treatment period divided into three phases.

SETTING

Office-based clinics.

PATIENTS

Hypercholesterolemic, with LDL cholesterol of 4.14 mmol/L or greater (> or = 160 mg/dL) and plasma triglycerides of 3.39 mmol/L or less (< or = 300 mg/dL). Four hundred sixty patients were screened; 224 patients were randomized into a double-blind treatment period; 203 completed the study; 6 dropped out because of adverse events.

INTERVENTION

Patients were treated with 10 mg or 20 mg of fluvastatin alone, 8 g or 16 g of cholestyramine alone, or combinations of these fluvastatin and cholestyramine dosages (six treatment groups).

MEASUREMENTS

Changes in lipid variables, particularly LDL cholesterol.

RESULTS

The 10-mg and 20-mg fluvastatin monotherapy groups showed considerable reductions in LDL cholesterol initially (-20.1% [SD, 8.8%] and -20.2% [SD, 10.1%], respectively); these reductions were maintained. Reductions in LDL cholesterol that resulted from the addition of cholestyramine, 8 g/d, to 10 mg of fluvastatin and 20 mg of fluvastatin were greater than those observed with monotherapy (10-mg fluvastatin--[10-mg fluvastatin plus cholestyramine], 9.1%; 95% CI, 3.8% to 14.4%) and 20-mg fluvastatin--[20-mg fluvastatin plus cholestyramine], 11.6%; CI, 6.5% to 16.8%). The increase in cholestyramine dose to 16 g/d in the three combination groups provided only a modest additional response.

CONCLUSIONS

Low-density lipoprotein cholesterol reductions of about 25% to 30% can be achieved with low-dose combination therapy with fluvastatin and cholestyramine. The addition of low-dose resin appears to produce greater overall cholesterol reduction than does a simple doubling of the fluvastatin dosage. The low-dose combination treatment was highly successful in achieving the goals of the National Cholesterol Education Program guidelines.

Amlodipine versus atenolol in essential hypertension

The efficacy and safety of amlodipine (2.5-10 mg) once daily was compared with atenolol (50-100 mg) once daily in patients with mild-to-moderate essential hypertension in a randomized, double-blind, parallel, placebo-controlled study. A total of 125 patients were randomly allocated at the end of a 4-week run-in placebo period to 8 weeks of double-blind treatment with amlodipine (n = 41), atenolol (n = 43), or placebo (n = 41). The placebo group had small mean changes in supine and standing blood pressure compared with baseline. The mean blood pressure changes from baseline 24 hours postdose in the amlodipine group (mean daily dose 8.8 mg) were -12.8/-10.1 mm Hg for supine blood pressure and -11.5/-9.8 mm Hg for standing blood pressure (p < 0.001 compared with placebo), and for the atenolol group (mean daily dose 83.7 mg) the changes were -11.3/-11.7 mm Hg for supine blood pressure and -13.3/-12.3 mm Hg for standing blood pressure (p < 0.001 compared with placebo). There were no statistically significant blood pressure differences between active treatments. The responder rates for amlodipine, atenolol, and placebo were 61.1, 64.9, and 11.1%, respectively. The blood pressure values taken over the 24-hour period at final visit revealed that amlodipine and atenolol maintained the supine blood pressure < or = 140/90 mm Hg throughout the period of observation; the corresponding time-effect curve for the placebo group was clearly in the hypertensive range. Both amlodipine and atenolol were well tolerated.(ABSTRACT TRUNCATED AT 250 WORDS)

Medium-induced fragility of Schwanniomyces

Schwanniomyces occidentalis has attracted interest because of its ability to metabolize starch and similar complex carbohydrates. Studies have been undertaken, mostly using defined media, to ascertain conditions for optimal production and secretion of hydrolytic enzymes. Here we demonstrate the fragility of Schw. occidentalis in many defined media. We especially examined viability in YNB (Yeast Nitrogen Base) plus 1% glucose. Without phosphate supplementation, viability was routinely very low at stationary phase (usually less than 37%), whereas viability of stationary-phase cultures in phosphate-supplemented YNB usually exceeded 97%. The negative implications of having many, presumably permeabilized, dead cells present in assays for secretion of enzymes by living yeast cells are discussed.