Doppler ultrasound surveillance of TIPS-patency in the era of covered stents – retrospective analysis of a large single-center cohort

Purpose The purpose of this study was to determine accuracy and necessity of long-term Doppler ultrasound (DU) surveillance of transjugular intrahepatic portosystemic shunt (TIPS) patency after implantation of an ePTFE-covered stent-graft (Viatorr).

Methods This single-center retrospective study includes 228 consecutive cirrhotic patients with TIPS implantation due to portal hypertensive complications. Standardized DU surveillance was scheduled 3 – 5 days, 3 months, and 6 months after TIPS implantation and every 6 months thereafter. Portal venography was performed in case of DU findings suspicious of TIPS dysfunction, clinical signs of recurrent portal hypertension, or refractory hepatic encephalopathy.

Results During a mean follow-up of 16.6 ± 23.4 months, 866 DU examinations were performed. Twenty-two cases of TIPS dysfunction were observed in 16 patients with no first dysfunction more than 4 years after implantation. Routine DU in asymptomatic patients had little therapeutic impact (0.75 %). DU and venography were concordant in 39/46 (84.8 %) paired examinations, and 1-, 2-, and 5-year primary TIPS patency was 87.4 %, 83.7 %, and 79.97 %, respectively. Patients with TIPS dysfunction and subsequent successful revision during the first 2 years of follow-up had a significantly higher risk (p = 0.001) of new dysfunction compared to those without TIPS dysfunction. Cumulative 1-, 2-, and 5-year survival was 68.7 %, 61.3 %, and 42.7 %, respectively.

Conclusions Despite acceptable accuracy, scheduled DU surveillance proved to have minor therapeutic impact. Thus, detailed DU surveillance is not useful in asymptomatic patients after 2 years of unremarkable follow-up. In contrast, long-term DU surveilleance should be performed in patients after successful revision of TIPS dysfunction and patients with prothrombotic states (e. g., portal vein thrombosis, Budd-Chiari syndrome).

Preoperative platelet transfusions to reverse antiplatelet therapy for urgent non-cardiac surgery: an observational cohort study

Essentials An increasing number of patients requiring surgery receive antiplatelet therapy (APT). We analyzed 181 patients receiving presurgery platelet transfusions to reverse APT. No coronary thrombosis occurred after platelet transfusion. This justifies a prospective trial to test preoperative platelet transfusions to reverse APT.

SUMMARY

Background Patients receiving antiplatelet therapy (APT) have an increased risk of perioperative bleeding and cardiac adverse events (CAE). Preoperative platelet transfusions may reduce the bleeding risk but may also increase the risk of CAE, particularly coronary thrombosis in patients after recent stent implantation. Objectives To analyze the incidence of perioperative CAE and bleeding in patients undergoing non-cardiac surgery using a standardized management of transfusing two platelet concentrates preoperatively and restart of APT within 24-72 h after surgery. Methods A cohort of consecutive patients on APT treated with two platelet concentrates before non-cardiac surgery between January 2012 and December 2014 was retrospectively identified. Patients were stratified by the risk of major adverse cardiac and cerebrovascular events (MACCE). The primary objective was the incidence of CAE (myocardial infarction, acute heart failure and cardiac troponine T increase). Secondary objectives were incidences of other thromboembolic events, bleedings, transfusions and mortality. Results Among 181 patients, 88 received aspirin, 21 clopidogrel and 72 dual APT. MACCE risk was high in 63, moderate in 103 and low in 15 patients; 67 had cardiac stents. Ten patients (5.5%; 95% CI, 3.0-9.9%) developed a CAE (three myocardial infarctions, four cardiac failures and three troponin T increases). None was caused by coronary thrombosis. Surgery-related bleeding occurred in 22 patients (12.2%; 95% CI, 8.2-17.7%), making 12 re-interventions necessary (6.6%; 95% CI, 3.8-11.2%). Conclusion Preoperative platelet transfusions and early restart of APT allowed urgent surgery and did not cause coronary thromboses, but non-thrombotic CAEs and re-bleeding occurred. Randomized trials are warranted to test platelet transfusion against other management strategies.

Tolerance of platelet concentrates treated with UVC-light only for pathogen reduction--a phase I clinical trial

BACKGROUND

The THERAFLEX UV-Platelets pathogen reduction system for platelet concentrates (PCs) operates with ultraviolet C light (UVC; 254 nm) only without addition of photosensitizers. This phase I study evaluated safety and tolerability of autologous UVC-irradiated PCs in healthy volunteers.

METHODS

Eleven volunteers underwent two single (series 1 and 2) and one double apheresis (series 3). PCs were treated with UVC, stored for 48 h and retransfused in a dose-escalation scheme: 12·5, 25% and 50% of a PC (series 1); one complete PC (series 2); two PCs (series 3). Platelet counts, fibrinogen, activated partial thromboplastin time, prothrombin time, D-dimer, standard haematology, temperature, heart rate, blood pressure and clinical chemistry parameters were measured. One- and 24-h corrected count increments were determined in series 2 and 3. Platelet-specific antibodies were assessed before and at the end of the study.

RESULTS

Neither adverse reactions related to transfusions nor antibodies against UVC-treated platelets were observed. Corrected count increments did not differ between series 2 and 3.

CONCLUSIONS

Repeated transfusions of autologous UVC-treated PCs were well tolerated and did not induce antibody responses in all volunteers studied. EudraCT No. 2010-023404-26.

Relationship between body condition score and ultrasound measurement of backfat thickness in multiparous Holstein dairy cows at different production phases

BACKGROUND

The validity of the body condition score (BCS) for evaluating subcutaneous fat has been questioned because of its subjectivity. With the advent of ultrasonography, backfat thickness (BFT) can be objectively measured and used to assess the energy status of dairy cows in conjunction with BCS.

OBJECTIVE

Determine the relationship between BCS and ultrasound measurements of BFT throughout the lactation cycle.

METHODS

Cows (n = 1123) were selected randomly and classified according to their lactation stage into four different groups. BCS was determined using a 5-point scale and BFT measurements were obtained using a 5-MHz linear transducer.

RESULTS

The correlation coefficient (r) for the relationship between BCS and BFT varied according to the stage of lactation. There was a high correlation (r = 0.96-0.98) and relationship (r(2) = 0.92-0.96) between BCS and BFT. The highest correlation was found at BFT values of 10-35 mm and BCS of 2-4.5 units.

CONCLUSION

BCS is a practical tool for evaluating body condition; furthermore, it may be as valid as BFT for the estimation of subcutaneous fat in Holstein dairy cows over time.

Selective serotonin reuptake inhibitors and tricyclic antidepressants in the acute treatment of chronic depression and dysthymia: a systematic review and meta-analysis

INTRODUCTION

Chronic depression represents a substantial portion of depressive disorders and is associated with severe consequences. This review examined the efficacy and acceptability of selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs) in the treatment of chronic depression. Additionally, the comparative effectiveness of the two types of antidepressants has been examined.

METHODS

A systematic search was conducted in the following databases: CENTRAL, MEDLINE, EMBASE, ISI Web of Science, BIOSIS, PsycINFO, and CINAHL. Primary efficacy outcome was a response to treatment; primary acceptance outcome was dropping out of the study. Only randomized controlled trials were considered.

RESULTS

We identified 20 studies with 22 relevant comparisons. 19 studies focused on samples with a majority of dysthymic patients. Both SSRIs and TCAs are efficacious in terms of response rates when compared to placebo (Benefit Ratio [BR]=1.49; p<0.001 for SSRIs and BR=1.74; p<0.001 for TCAs) and no statistically significant differences between the active drugs and placebo in terms of dropout rates could be found. No differences in effectiveness were found between SSRIs and TCAs in terms of response rates (BR=1.01; p=0.91), yet, SSRIs showed statistically better acceptability in terms of dropout rates than TCAs (Odds Ratio [OR]=0.41; p=0.02).

LIMITATIONS

The methodological quality of the primary studies was evaluated as unclear in many cases and more evidence is needed to assess the efficacy of SSRIs and TCAs in patients suffering from chronic forms of depression other than dysthymia.

CONCLUSIONS

This systematic review provides evidence for the efficacy of both SSRIs and TCAs in the treatment of chronic depression and showed a better acceptability of SSRIs.

A Method for Field Infestation with Meloidogyne incognita

A field inoculation method was developed to produce Meloidogyne spp. infestation sites with minimal quantities of nematode inoculum and with a reduced labor requirement compared to previous techniques. In a preseason-methyl bromidefumigated site, nematode egg suspensions were delivered at concentrations of 0 or 10(x) eggs/m of row where x = 2.12, 2.82, 3.52, or 4.22 through a drip line attached to the seed firmer of a commercial 2-row planter into the open seed furrow while planting cowpea. These treatments were compared to a hand-inoculated treatment, in which 10(3.1) eggs were delivered every 30 cm in 5 ml of water agar suspension 2 weeks after planting. Ten weeks after planting, infection of cowpea roots was measured by gall rating and gall counts on cowpea roots. A linear relationship between the inoculation levels and nematode-induced galls was found. At this time, the amount of galling per root system in the hand-inoculated treatment was less than in the machine-applied treatments. Advantages of this new technique include application uniformity and low population level requisite for establishing the nematode. This method has potential in field-testing of Meloidogyne spp. management strategies by providing uniform infestation of test sites at planting time.

Vertical Distribution of Rotylenchulus reniformis in Cotton Fields

The possible impact of Rotylenchulus reniformis below plow depth was evaluated by measuring the vertical distribution of R. reniformis and soil texture in 20 symptomatic fields on 17 farms across six states. The mean nematode population density per field, 0 to 122 cm deep, ranged from 0.4 to 63 nematodes/g soil, and in 15 fields more than half of the R. reniformis present were below 30.5 cm, which is the greatest depth usually plowed by farmers or sampled by consultants. In 11 fields measured, root density was greatest in the top 15 cm of soil; however, roots consistently penetrated 92 to 122 cm deep by midseason, and in five fields in Texas and Louisiana the ratio of nematodes to root-length density within soil increased with depth. Repeated sampling during the year in Texas indicated that up to 20% of the nematodes in soil below 60 cm in the fall survived the winter. Differences between Baermann funnel and sugar flotation extraction methods were not important when compared with field-to-field differences in nematode populations and field-specific vertical distribution patterns. The results support the interpretation that R. reniformis below plow depth can significantly impact diagnosis and treatment of cotton fields infested with R. reniformis.

Rotylenchulus reniformis below Plow Depth Suppresses Cotton Yield and Root Growth

Damage to cotton by Rotylenchulus reniformis below plow depth was evaluated in a sandy clay loam soil at Weslaco, Texas. In December 1999, 14 holes on 51-cm centers were dug 91 cm deep along the planting bed and adjacent furrow and 2 ml of 1,3-dichloropropene was placed 91, 61, and 30 cm deep as each hole was refilled and packed. This technique eliminated 96%, 81%, and 74% of R. reniformis down to 107 cm at distances 0, 25, and 51 cm laterally from the point of application (P </= 0.05), whereas chisel fumigation at 168 liters/ha 43 cm deep reduced nematode numbers only in the top 61 cm (P </= 0.001). Manual placement of fumigant increased yield 92%; chisel fumigation increased yield 88% (P </= 0.005). A second experiment in February 2001 placed fumigant 43 or 81 cm deep, or at both 43 and 81 cm. Holes alone had no significant effect on nematode density at planting, midseason or harvest, on root length density at midseason, or on cotton lint yield. Fumigant at 43 cm reduced nematode numbers above fumigant application depth at planting 94% (P </= 0.02), at midseason 37% (P </= 0.09), and at harvest 0%, increasing yield 57% (P </= 0.002). Fumigant at 81 cm reduced nematode numbers above fumigant application depth at planting 86% (P </= 0.02), at midseason 74% (P </= 0.02), and at harvest 48% (P </= 0.01), increasing yield 53% (P </= 0.002). Fumigating at both 43 and 81 cm reduced nematode numbers above 90 cm 94% at planting and 79% at midseason, increased midseason root-length density 14-fold below 76 cm, and doubled yield (P </= 0.02 in all cases).

Investigation of the Neutron Quantum States in the Earth's Gravitational Field

We studied the neutron quantum states in the potential well formed by the Earth's gravitational field and a horizontal mirror. The estimated characteristic sizes of the neutron wave functions in two lowest quantum states correspond to their expectations with an accuracy of ≈25 %. The spatial density distribution in a standing neutron wave above a mirror was measured for a set of a few lowest quantum states. A position-sensitive neutron detector with an extra high spatial resolution of 1 μm to 2 μm was developed and tested for this particular task. Although this experiment was not designed or optimized to search for an additional short-range force, nevertheless it allowed us to slightly improve the published boundary in the nanometer range of characteristic distances. We studied systematical uncertainties in the chosen "flow-through" method as well as the feasibility to improve further the accuracy in this experiment.

Effect of glucocorticoïd receptor ligands on myosin heavy chains expression in rat skeletal muscles during controllable stress

The influence of agonist (dexamethasone) and antagonist (mifepristone) of glucocorticoïd receptor during controllable painless stress was evaluated on myosin heavy chains expression in three masticatory and two nape rat muscles: anterior digastric (AD), anterior temporalis (AT), masseter superficialis (MS), longissimus capitis (L) and rectus capitis dorsalis major (R). The relative amounts of myosin heavy chain (MHC) protein isoform contained were significantly affected in four muscles studied by dexamethasone and in three muscles studied under mifepristone, versus control during the stress procedure, after only 1 week of treatment. The control group AT muscles contained respectively 18.2% of MHC 2A, 34.5% of MHC 2X and 47.4% of MHC 2B. The effects of dexamethasone and mifepristone were opposite in this muscle: under dexamethasone, the relative proportions of the three isoforms were 14.2, 31.0 and 54.8%: consequently, MHC 2A and 2X decreased with the profit of 2B. Under mifepristone, the relative proportions were 21.1, 36.6 and 42.3% (MHC 2A and 2X increased to the detriment of 2B). The L muscle was not affected by the two treatments and MS muscle was only affected by dexamethasone. Dexamethasone increased MHC 2B to the detriment of MHC 2A in MS, AD and R. Mifepristone and dexamethasone induced the same changes in AD. The mifepristone treatment decreased the MHC 2X profile in R. Under dexamethasone, four muscles exhibited a significantly higher proportion of the more rapid isoforms than under mifepristone. A previous work showed that controllable stress induced a marked increase in the relative expression of MHC 2B in the same skeletal muscles (Martrette et al. , 1998). Our results confirm then a significant participation of glucocorticoïd in MHC isoform expression during controllable stress.

Depth Distribution of Rotylenchulus reniformis Under Different Tillage and Crop Sequence Systems

ABSTRACT The population density of the reniform nematode, Rotylenchulus reniformis, was monitored at depths of 0 to 30, 30 to 60, 60 to 90, and 90 to 120 cm in a tillage and crop sequence trial in south Texas in 2000 and 2001. Main plots were subjected to three different tillage systems: conventional tillage (moldboard plowing and disking), ridge tillage, and no-tillage. Subplots were planted with three different crop sequences: spring cotton and fall corn every year; spring cotton and fall corn in one year, followed by corn for two years; and cotton followed by corn and then grain sorghum, one spring crop per year. The population density of R. reniformis on corn and grain sorghum was low throughout the soil profile. In plots planted with spring cotton and fall corn every year, fewer nematodes were found at depths of 60 to 120 cm in the no-tillage and ridge tillage systems than in the conventional tillage system. Population densities were lower at depths of 0 to 60 cm than at 60 to 120 cm. Soil moisture and cotton root length did not affect nematode population densities in the field. When soil was placed in pots and planted with cotton in the greenhouse, lower population densities developed in soil taken from depths of 0 to 60 cm than in soil from depths of 60 to 120 cm. Final nematode populations were similar in size in soil from the different tillage systems, but reproductive factors were higher in soil from plots with reduced-tillage systems than in soil from plots with conventional tillage. Reduced-tillage practices lowered the risk of increases in R. reniformis populations and reduced population densities following 2 years of non-hosts throughout soil depths, but population densities resurged to the same high levels as in soil planted with cotton every year during one season of cotton.

Influence of the Lurcher mutation on myosin heavy chain expression in skeletal and cardiac muscles

This study evaluated the influence of Lurcher mutation, characterized by degeneration of cerebellar Purkinje cells, granule cells, and inferior olive neurons, on cardiac and skeletal muscles: one respiratory (diaphragm, Dia), three masticatory (anterior temporalis, AT; masseter superficialis, MS and anterior digastric, AD), one hind limb (soleus, S), entire tongue (T), and one cardiac (ventricle, V) muscles. Body and muscle weight, muscle protein content, and myosin heavy chain (MHC) isoforms relative expression were then compared in Lurcher mutant mice vs. normal, according to sex. Male body weight was always greater than female one, but there was no specific muscle difference in females, except for T relative weight which was greater in normal females. Muscle protein concentration was greater in normal males except for AD and T in which it was lower. Lurcher mutant mice showed a reduced whole body growth but no specific muscle atrophy (except in male AT), and a global decrease in muscle protein content which made muscles more fragile (except in female Dia and male T, in which it was greater). Lurcher mutation induced a global reduction of muscle protein concentration whereas a general influence of sex could not be disclosed. Concerning MHC relative composition, all the muscles were fast-twitch: Dia, AT, MS, AD, S, and T predominantly expressed the fast type 2 MHC isoforms, except female S, whereas V contained only MHC alpha, also a fast MHC. Female muscles were slower than male ones and classification of muscles in terms of shortening velocity was comparable in normal male and female. In other respects, male Lurcher mutant muscles were slower and consequently more fatigue resistant than normal, except T which became faster and less fatigue resistant. On the contrary, in female mutants, only the Dia was slower than normal one, MS and AD were comparable to normal ones and finally, AT, S, and T were faster than normal ones. It should be noted that a developmental MHC (neonatal) was present in Lurcher AD. Motor control, which influences muscle structure, is altered in Lurcher mutant and could be one of the causal factor of the fast-to-slow MHC switches observed in some mutant muscles. It seems therefore that cerebellar Purkinje cells, granule cells, and inferior olive neurons are very important in maintaining the structural integrity of both cardiac and skeletal muscle, and their degeneration is accompanied by important muscles modifications. J. Cell. Biochem. Suppl. 36: 222-231, 2001.

Impact of vascular branching sites on focal progression of allograft vasculopathy in transplanted hearts

BACKGROUND

Cardiac allograft vascular disease (CAVD) represents one of the most accelerated progressing coronary syndromes in the human heart. A variety of risk factors have been identified over recent years; however, little is known about the influence of physical forces. As a model for differences in focal blood flow dynamics, we analyzed progression of intimal hyperplasia at vascular bifurcational sites using intravascular ultrasound (IVUS).

METHODS

The most diseased vascular sites ("worst sites") in 59 coronary arteries were assessed (30 MHz, motorized pull back) in 25 consecutive heart transplant recipients at baseline (52.8+/-15.3 days postoperatively) and after 1 year of follow up (360.5+/-24.9 days). Progression of intimal hyperplasia was compared between branching and non-branching lesions as well as in focal relation to the position of the flow divider.

RESULTS

A total of 41 (69.5%) worst sites were identified at branching locations. Progression of intimal hyperplasia was found to be significantly more severe at bifurcational sites with an increase in plaque area by 1.5+/-1.8 mm(2) in branching versus 0.4+/-0.6 mm(2) in non-branching lesions (P=0.015). The highest rate in focal progression was found at the opposite site of the flow divider with an increase in maximal intimal thickness by 0.3+/-0.23 mm (180 degrees ) as compared to 0.11+/-0.15 mm (90 degrees, P<0.001) and 0.15+/-0.15 mm (P=0.014) at 270 degrees.

CONCLUSIONS

Using serial intravascular ultrasound examinations, vascular branching sites could be identified to be predisposing locations not only for a donor related arteriosclerosis, but also for progression of intimal hyperplasia within transplanted hearts. The highest regional increase in intimal thickness was found at the outer wall of the flow divider, suggesting focal shear or wall stress to be involved in pathogenesis.

Progression of cardiac allograft vascular disease as assessed by serial intravascular ultrasound: correlation to immunological and non-immunological risk factors

OBJECTIVE

To characterise the severity and progression of cardiac allograft vascular disease (CAVD) in a large patient cohort, and to evaluate possible immunological and non-immunological risk factors for progression.

DESIGN

A prospective observational study using intravascular ultrasound.

SETTING

Two university hospitals.

PATIENTS AND MAIN OUTCOME MEASURES

Changes in focal plaque, lumen, and total vessel area (worst site method) were assessed at baseline and after 12.1 (2.8) months (mean (SD)) of follow up in a cohort of 96 patients (79 male, 17 female; mean age 48.7 (9.6) years; time post-transplant 26.0 (32.4) months).

RESULTS

Overall, the mean (SD) intimal index of worst sites increased by 6.7 (8.8)%. The increase in the first 12 months was 7.5 (9.4)%, v 5.9 (8.0)% after the first year (NS). Analysing immunological and non-immunological risk factors (age, underlying disease, sex, donor age, immunosuppression, cytomegalovirus, rejection episodes, cholesterol), low density lipoprotein (LDL) cholesterol was found to be the most important predictor of severe progression (as defined by an increase in intimal index of >/= 15% (p = 0.01).

CONCLUSIONS

Progression of CAVD is characterised by a continuing increase in intimal hyperplasia, especially within the first year after heart transplantation. LDL cholesterol is an important predictor of major progression.

Transfer of Biological Soil Suppressiveness Against Heterodera schachtii

ABSTRACT Heterodera schachtii-suppressive soil at a rate of either 1 or 10% (dry wt/wt) transferred suppressiveness against the beet cyst nematode to fumigated field plots when mixed into the upper 10-cm soil layer. Soil suppressiveness was established after 1 month of moist fallow and 77 days of Swiss chard cropping in the 10% transfer treatment and after 230 days in the 1% transfer treatment. The number of infective second-stage juveniles (J2) of H. schachtii, monitored initially at 150 degree-day intervals and later at 300 degree-day intervals, indicated the status of suppressiveness in the different treatments during the cropping period. In a greenhouse experiment, amending fumigated field soil with 0.1, 1.0, or 10% suppressive soil, suppressed multiplication of H. schachtii when soils were infested with an additional 5,000 J2. In a second greenhouse experiment, a fumigated sandy loam amended with 10 or 25% suppressive soil and a fumigated loam amended with 25% suppressive soil had significantly fewer eggs per cyst than the nonamended fumigated treatments when 1,000 J2 were added.

Dystonia musculorum mutation and myosin heavy chain expression in skeletal and cardiac muscles

This study evaluated the influence of dystonia musculorum (dt) mutation, characterized by spinocerebellar fibers degeneration, on cardiac and skeletal muscles: one respiratory (diaphragm, Dia), three masticatory (anterior temporalis, AT; masseter superficialis, MS; and anterior digastric, AD), one hindlimb (soleus, S), tongue (T), and one cardiac (ventricle, V). Body and muscle weight, muscle protein content, and myosin heavy chain (MHC) isoforms relative expression were then compared in dt mutant mice and in normal mice, according to sex. Male body and muscle weight was always greater than that of females, but there was no specific muscle difference in females. dt mutant mice showed a reduced whole body growth but no specific muscle atrophy, as well as a global decrease in muscle protein content that made muscles more fragile. dt mutation induced a global reduction of muscle protein concentration, whereas a general influence of sex could not be disclosed. Concerning MHC relative composition, all the muscles were fast-twitch: Dia, AT, MS, AD, S, and T expressed predominantly the fast type 2 MHC isoforms, whereas V contained only MHC alpha, also a fast MHC. Female muscles were slower than male muscles, except for S, which was faster. However, classification of muscles in terms of shortening velocity was very different in normal males and females. In other respects, dt mutant muscles were slower and consequently more fatigue resistant than normal, except for S, which became faster and less fatigue resistant. dt mutation exhibits then a specific effect on this continually active postural muscle. In the other muscles, global increased fatigue resistance could constitute an adaptive response to work requirements modifications linked to the muscle damage. It should be noted that a developmental MHC (neonatal) was present in female dt AD. Innervation, which influences muscle structure, is altered in dt mutant and could be another causal factor of the fast-to-slow MHC switches. It appears that dystonin, the dt gene product, is very important in maintaining the structural integrity of both cardiac and skeletal muscle and in its absence, the muscle becomes more fragile and is damaged by modified activity.

Biological Suppression and Natural Population Decline of Heterodera schachtii in a California Field

ABSTRACT Soil suppressiveness to Heterodera schachtii was demonstrated in a field at the research station of the University of California, Riverside. In two field trials planted to Swiss chard (Beta vulgaris), introduced H. schachtii multiplied 2.7 and 1.7 times more in preplant metam sodium-fumigated plots than in nontreated plots in 1994 and 1995, respectively. In greenhouse experiments, preplant treatments with metam sodium, methyl bromide, methyl iodide, formaldehyde, and aerated steam reduced suppressiveness of soil against H. schachtii to undetectable levels. H. schachtii multiplied significantly less in nontreated soil than in treated soil on Swiss chard. At harvest, the number of infective second-stage juveniles in suppressive soil was close to the lowest detection level, whereas high numbers were encountered in soils initially treated. In a crop rotation trial with host crops of H. schachtii, introduced H. schachtii populations were monitored for five cropping periods over 30 months in initially fumigated versus nontreated suppressive field plots. In fumigated plots, H. schachtii population levels increased in the first and second cropping periods and then declined in the third cropping period. In the fourth and fifth cropping periods, the nematode reproduction factor in the initially fumigated plots was not significantly different from that in suppressive plots.

Effects of controllable stress on masticatory behaviour and muscle structure: partial protective effect of clomipramine

The influence of controllable painless stress and clomipramine treatment was evaluated on masticatory behaviour and myosin heavy chain expression in masticatory rat muscles: anterior digastric, anterior temporalis and masseter superficialis. The adult fast isoforms of myosin heavy chains detected were myosin heavy chains 2A, 2X and 2B. The myosin heavy chains composition of anterior temporalis muscle was unchanged by stress or by treatment. In anterior digastric and masseter superficialis muscles, stress induced an increase in 2B and a decrease in 2X and 2A. Under stress, whereas the myosin heavy chains composition of anterior temporalis and anterior digastric muscles was unaffected by clomipramine, this drug modified significantly the myosin heavy chains composition of masseter superficialis muscle which became comparable to that of control muscle. Stress-induced myosin heavy chains transformations led to an increased velocity of anterior digastric and masseter superficialis muscles but not anterior temporalis muscle. Gnawing and mastication were increased by stress and incisor grinding was reduced. Stress shortened the duration of gnawing and increased the fatigability of anterior digastric and masseter superficialis muscles, whereas clomipramine increased the duration of mastication and reduced the fatigability of masseter superficialis muscle. Stress produces selective changes in masticatory muscles and behaviour. This study demonstrates the muscle type-specific protective effect of clomipramine against stress-induced structural transformations of masseter superficialis muscle and the specific concomitant behavioural modifications.

Effect of controllable stress on myosin heavy chain expression and muscle-specific protection by clomipramine

This study evaluated the influence of a controllable and painless stress, conditioned bright-light active-avoidance, on the expression of myosin heavy chain (MHC) protein isoforms in two nape and three masticatory rat muscles: longissimus capitis (L), rectus capitis dorsalis major (R), anterior digastric (AD), anterior temporalis (AT) and masseter superficialis (MS). The effects of a concomitant antidepressant treatment with clomipramine (CMI) on the muscle structure were also investigated. The three adult fast MHC isoforms were detected in all muscles studied: MHC 2A, 2X and 2B. The AT structure was not significantly modified by stress either under saline or under CMI treatment. In the other muscles studied, the stress situation induced a marked increase in the relative expression of MHC 2B and a decrease in MHCs 2X and 2A, except in L in which the MHC 2A decrease did not reach a statistically significant level. Under controllable stress, the CMI treatment led to the same MHC profile in AT, L, R and AD as saline, except in L where the MHC 2X decrease was no longer statistically significant. However, in MS, under controllable stress and CMI treatment, the MHC distribution was significantly different from the stressed saline-treated group and became comparable to the control again. MHC 2B has a higher shortening velocity than MHC 2X, which has a higher one than MHC 2A. According to total MHC isoform expression, the controllable stress-induced transformations would thus lead to increased velocity of all five muscles studied except in AT. This latter seems, therefore, not very sensitive to environmental requirements. Our results indicate that controllable stress produces important changes in the contractile properties of nape and masticatory muscles. Furthermore, this study demonstrates the protective effect of CMI against muscle structure transformations induced by controllable stress in MS, and that these effects are muscle type-specific.

Effects of pre- and perinatal exposure to hypergravity on muscular structure development in rat

This study evaluated the influence of precocious exposure to hypergravity on the expression of myosin heavy chain (MHC) protein isoforms in nape, masticatory and respiratory developmental rat muscles. Pregnant females were maintained at 1.8 g from the 11th day of gestation to the 7th day after birth. The 7-day-old rats were used for muscle sampling. Hypergravity induced a marked decrease in the weight and protein content of all six muscles. Three MHC isoforms were detected in the young rats' muscles: embryonic (E), perinatal (P) and slow type 1 MHC. In centrifuged nape and masticatory muscles, there was a decrease in MHC E and an increase in P without reduction (indeed, even an increase) in MHC 1, whereas in the respiratory muscle MHC E was increased and MHC 1 decreased. These results indicate that hypergravity produces important changes in the contractile properties not only of antigravity muscles but also masticatory and respiratory muscles. MHC P has a higher shortening velocity than MHC E, which has a higher one than MHC 1. The hypergravity-induced transformations of MHC isoforms would thus lead to increased velocity of all muscles studied. In spite of the observation of a hypergravity-induced muscle hypotrophy, the results of this study reflect the adaptational properties of developing muscles to increased gravitational forces.

Improvement of diffraction quality upon rehydration of dehydrated icosahedral Enterococcus faecalis pyruvate dehydrogenase core crystals

Members of the family of 2-oxoacid dehydrogenase multienzyme complexes catalyze the oxidative decarboxylation of alpha-keto acids and are among the most remarkable enzymatic machineries in the living cell. These multienzyme complexes combine a highly symmetric (cubic or icosahedral) core with a dynamic and flexible arrangement of numerous subunits and domains surrounding the core. The center of the complex is formed by either 24 or 60 copies of dihydrolipoamide acetyltransferase (E2)-a multidomain enzyme. The hollow icosahedral cores are composed of 60 identical subunits of the catalytic domain of E2 with a molecular weight of about 1.8 million Da. Bipyramidal crystals suitable for X-ray diffraction of the icosahedral core of the pyruvate dehydrogenase multienzyme complex from Enterococcus faecalis were grown up to 0.7 mm in each dimension. The crystals belong to space group R32 with a = b = 244.3 A (hexagonal setting), and have a solvent content of 73%. The asymmetric unit contains one-third of the molecule, i.e., 20 of the 60 subunits. Initial X-ray crystallographic data to 7 A resolution were collected at cryotemperatures at synchrotron facilities. Interestingly, the diffraction was improved significantly upon rehydrating dehydrated crystals and extended to 4.2 A.

A novel type of pyridine nucleotide-disulfide oxidoreductase is essential for NAD+- and NADPH-dependent degradation of epoxyalkanes by Xanthobacter strain Py2

Epoxide degradation in cell extracts of Xanthobacter strain Py2 has been reported to be dependent on NAD+ and dithiols. This multicomponent system has now been fractionated. A key protein encoded by a DNA fragment complementing a Xanthobacter strain Py2 mutant unable to degrade epoxides was purified and analyzed. This NADP-dependent protein, a novel type of pyridine nucleotide-disulfide oxidoreductase, is essential for epoxide degradation. NADPH, acting as the physiological cofactor, replaced the dithiols in epoxide conversion.

Influence of stress and occlusal interference on the EMG activity of some masticatory muscles during a single mastication cycle

The aim of the study was to investigate the influence of stress on the open-close activity in mastication, using an animal model. For this, we have compared the single-motor activities of three muscles: anterior digastric (AD), anterior temporalis (AT) and the superficial masseter (MS) in different groups of rats classed according to emotional state and dental occlusion. The EMG graphs have been analysed by the method proposed by the Weijs & Dantuma (1975). The results show that a dominant action of the stress on the AD and a combined action of the stress and the occlusal state on AT and MS occur during a single mastication cycle. A suppression of the reflex myotatic inhibition for AT and MS occurred in the presence of an occlusal interference.

Substitution of Arg214 at the substrate-binding site of p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens

The gene encoding p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens was cloned in Escherichia coli to provide DNA for mutagenesis studies on the protein product. A plasmid containing a 1.65-kbp insert of P. fluorescens chromosomal DNA was obtained and its nucleotide sequence determined. The DNA-derived amino acid sequence agrees completely with the chemically determined amino acid sequence of the isolated protein. The enzyme is strongly expressed under influence of the vector-encoded lac promotor and is purified to homogeneity in a simple three-step procedure. The relation between substrate binding, the effector role of substrate and hydroxylation efficiency was studied by use of site-directed mutagenesis. Arg214, in ion-pair interaction with the carboxy moiety of p-hydroxybenzoate, was replaced with Lys, Gln and Ala, respectively. The affinity of the free enzymes for NADPH is unchanged, whereas the affinity for the aromatic substrate is strongly decreased. For enzymes Arg214-->Ala and Arg214-->Gln, the effector role of substrate is lost. For enzyme Arg214-->Lys, binding of p-hydroxybenzoate highly stimulates the rate of flavin reduction. In the presence of substrate or substrate analogues, the reduced enzyme Arg214-->Lys fails to stabilize the 4 alpha-hydroperoxyflavin intermediate, essential for efficient hydroxylation. Like the wild-type, enzyme Arg214-->Lys is susceptible to substrate inhibition. From spectral and kinetic results it is suggested that secondary binding of the substrate occurs at the re side of the flavin, where the nicotinamide moiety of NADPH is supposed to bind.

[Evaluation of a histochemical method specific for myosin ATPase activity in the masticatory muscles of the rat]

A biological study of masticatory muscle behaviour (Divry and Westphal, 1991) suggested the analysis of physiologic correlates (biologic parameters related to a behavioural event) such as histochemical reactions of muscular fibres studied by M-ATPase and SDH activities. For such investigations, routine methods are needed. In the present study, a modification of the original method of Tunell and Hart (1977) was used, in which three features of the original alkaline preincubation method (composition, incubation time and pH) were modified. These allowed a single step differentiation of the various fibre types found in rat masticatory muscles, for which the classical technics gave only a weak contrast, not suitable for image analysis. Acid preincubation was also tested but failed to give new information. By combining this modified technic with SDH staining (Nachlas, 1957) a classification of fibres into 12 theoretical types was proposed.

A preliminary study of manducatory behaviour influenced by stress and dental occlusion

Stress and dental occlusion often are incriminated as causes of dysfunction of the manducatory system. How and in what degree these two factors came through has not yet been clearly worked out. Our study is carried out on a group of rats presenting one or both of these two factors and we proposed to examine the duration and frequency of some components of their behaviour--intake of solid food and grooming, to detect some possible perturbations on manducatory behaviour caused by stress and/or occlusal interference. Our study shows that stress induced by emotion or occlusal interference will change the microstructure of behaviour rather than the global component in itself. This implies that we must find a clear definition of the different types of microstructure to find out which ones are changed by the two incriminating factors and which part of the behaviour component will remain stable.