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[Power Doppler Imaging and prostate cancer: optional or necessary technique?].

PURPOSE: To evaluate the value of power Doppler sonography (PDS) in patients with a serum PSA level greater than 3.5 ng/ml and note the advantages of PDS in management of biopsy cores and staging in prostate cancer. MATERIAL AND METHODS: A group of 579 patients with a serum PSA level greater than 3.5 ng/ml underwent sextant biopsies. PDS of the prostate was performed in all patients before biopsy indication. Patients underwent six initial sextant biopsies without Doppler. In 141 patients who retained an elevated serum PSA level, an additional series of six to eight ultrasound-guided biopsies with Doppler were indicated. A total of 299 cancers were diagnosed (126 palpable) after initial biopsies and 85 (13 palpable) after additional biopsies. One hundred seven patients with localized cancer (48 palpable) underwent a radical prostatectomy. RESULTS: An echographic or vascular anomaly was detected in 335 patients; after biopsies this anomaly corresponded to 260 cancers, 39 of which were not visible (false-negative Doppler results). The negative predictive value was 84% and there was no significant relation between PSA level and negative predictive value. After initial biopsies, if an abnormal Doppler signal was present the risk of having positive additional biopsies was 83%. Abnormal disoriented irregular vessels were present in 69% of patients with a Gleason score of 7 or higher versus 31% in patients with a Gleason score less than 7 (p<0.01). Twenty out of 39 patients with T1c cancer invisible with PDS and not palpable (13% of all cancers) underwent a radical prostatectomy. Eleven of 16 cancers with a Gleason score of 6 or less were found insignificant, but in two cases the lesion was advanced (p<0.01). Of cancers with a tumor vessel crossing the capsule, 71% presented an extraprostatic extension (Se: 37.5%, Spe: 93%, PPV: 71%, NPV: 78%) (p<0.01). CONCLUSION: In prostatic cancer, PDS allows evaluation of aggressiveness features and can optimize the number of useful biopsy cores.

Aged↗

Education of preventive medicine residents: alcohol, tobacco, and other drug abuse.

BACKGROUND: Generalist physicians' addiction training is inadequate, but general preventive medicine residency (PMR) programs have not been studied. We determined PMR programs' alcohol, tobacco, and other drug abuse (ATOD) training from 1995 to 2000 and identified barriers to this education. METHODS: Interviewer-administered telephone survey of program directors (PDs) of accredited PMR programs in the United States. RESULTS: We interviewed all 41 PMR PDs. While 78% of PMR PDs reported interest in increasing ATOD education, for 68% it was not a high educational priority. Tobacco ranked in the top third of preventive medicine topics by 58%, while alcohol and other drugs ranked in the bottom third by 48% and 52%, respectively. Twenty-two percent of programs required a clinical ATOD rotation, most commonly smoking-cessation clinics. Only 29% of PMR PDs felt that residents were well prepared in clinical aspects of ATOD, while 60% felt that residents were prepared in ATOD research and public health issues. The most commonly reported barriers to ATOD training were lack of resident interest and defined competencies (64% each); limited faculty time (59%); limited teaching time (54%); lack of available teaching materials (53%); and lack of faculty expertise (51%). CONCLUSIONS: While the majority of PMR PDs recognize the importance of incorporating teaching about addictions into training, much of the ATOD education in PMRs focuses on tobacco alone. Setting educational standards, defining competencies, investing in faculty development, and creating ATOD curricular modules are important next steps toward preparing preventive medicine physicians to effectively reduce the public health toll of addictions.

Alcohol Drinking↗

Arthroscopic rotator cuff repair: analysis of technique and results at 2- and 3-year follow-up.

We present 53 patients who underwent arthroscopic rotator cuff repair and had a minimum of 2-year follow-up. Most tears were avulsions of the supraspinatus from the greater tuberosity, some with associated longitudinal tears. Longitudinal tears were repaired with a side-to-side suturing technique. Avulsion tears from the tuberosity were repaired using nonretrievable suture anchors. Traditional open-mobilization techniques, such as elevating the cuff off the glenoid neck and scapular fossa, and cutting the coraco-humeral ligament, were performed arthroscopically as needed. All repairs were performed using O-PDS or 1-PDS suture and a 7-mm suture punch for suture delivery. Both simple and mattress suture configurations were used. An anterolateral operative portal was used in most cases. A modified UCLA rating system that included additional points for abduction range of motion and strength was adapted for clinical evaluation in this study (maximum score, 45 points). The average preoperative rating was 17 (range, 9 to 26). The average postoperative rating was 41 (range, 16 to 45). There were 36 excellent (41 to 45 points), 13 good (36 to 40 points), 1 fair (30 to 35 points), and 3 poor (< 30 points) results. We have seen intraoperative but no cases of postoperative anchor pullout. The simple sutures performed as well as, and in some ways better than, mattress configurations. All fair and good results were with O-PDS. To perform an arthroscopic repair, the tear must be well visualized and mobilizable back to the tuberosity with only moderate tension. The anterolateral operative portal has been very useful because it allows better angle of entry for instruments and anchors and improved visualization in the subacromial space. The use of PDS and simple suture configurations has made the repair technically easier to perform with the instruments that are currently available. We do recommend 1-PDS suture because it breaks less easily even though it is slightly more difficult to deliver and tie. Arthroscopic cuff mobilization is relatively simple and has allowed us to repair larger tears. Based on our experience, arthroscopic rotator cuff repair is technically achievable and a superior alternative in selected cases for an experienced shoulder arthroscopist. Patients who underwent arthroscopic repairs had less scarring and shorter hospital stays and, we believe, less postoperative pain and easier rehabilitation compared with open repairs.

Adult↗

Outcomes of laser in situ keratomileusis in patients with pigment dispersion syndrome.

PURPOSE: To analyze the outcome of laser in situ keratomileusis (LASIK) in patients with pigment dispersion syndrome (PDS). SETTING: Outpatient ambulatory laser vision correction centers. METHODS: This noncomparative case series reviewed the medical records of 12 patients (22 eyes) who had clinical features consistent with PDS at the time of the initial preoperative refractive evaluation and had LASIK surgery. RESULTS: Twenty eyes (90.9%) of 11 patients had an uneventful course after LASIK and a good final uncorrected visual acuity (mean follow-up 26 months). One patient (2 eyes) with PDS and suspicion of glaucoma on topical beta-blocker therapy had delayed healing, fluctuations in vision, and a lengthy visual recovery. CONCLUSIONS: Corneal findings of PDS do not appear to affect the intraoperative or postoperative outcomes of LASIK. However, patients who have PDS in the context of glaucoma and therapy with an intraocular-pressure-lowering agent may experience delayed healing and a less predictable visual outcome.

Adult↗

Morphological characterization of microspheres, films and implants prepared from poly(lactide-co-glycolide) and ABA triblock copolymers: is the erosion controlled by degradation, swelling or diffusion?

Erosion of biodegradable parenteral delivery systems (PDS) based on ABA copolymers consisting of poly(L-lactide-co-glycolide) (PLGA) A-blocks attached to polyethylene oxide (PEO) B-blocks, or PLGA is important for the release of macromolecular drugs. The degradation behavior of four types of PDS, namely extruded rods, tablets, films and microspheres, was studied with respect to molecular weight, mass, polymer composition and shape and microstructure of the PDS. For each device the onset time of bulk erosion (t(on)) and the apparent rate of mass loss (k(app)) were calculated. In the case of PLGA, the t(on) was 16.2 days for microspheres, 19.2 days for films and 30.1 days for cylindrical implants and tablets. The k(app) was 0.04 days(-1) for microspheres, 0.09 days(-1) for films, 0.11 days(-1) for implants and 0.10 days(-1) for tablets. The degradation rates were in the same range irrespective of the geometry and the micrographs of eroding PDS demonstrated pore formation; therefore, a complex pore diffusion mechanism seems to control the erosion of PLGA devices. In contrast, PDS based on ABA copolymers showed swelling, followed by a parallel process of molecular weight degradation and polymer erosion, independent of the geometry. The contact angles of ABA films increased either with decreasing PEO content or with increasing chain length of the PEO B-blocks. In summary, the insertion of a hydrophilic B-block leads to an erosion controlled by degradation of ABA copolymers, whereas for PLGA a complex pore diffusion of degradation products controls the rate of bulk erosion.

Biodegradation, Environmental↗

Scanning electron microscopy study including maceration techniques of an absorbable alloplastic implant designed for the reconstruction of ventral abdominal wall defects.

The interposition of synthetic material represents the most generally acknowledged method for achieving a tension-free surgical repair of major abdominal wall defects. As permanent materials are frequently associated with severe complications (rejection, peritonitis, enterocutaneous fistula, erosive invasion into the intestine), a newly designed absorbable prosthetic (polydioxanone, PDS) has been developed. The ellipsoid implant is composed of a knitted envelope and a filling of loosely arranged filaments. Interpositioning of the implant into an artificial circular abdominal wall defect was carried out on 30 Wistar rats. Explantation was performed 21 days post implantationem (p.i.), 42 days p.i. and 180 days p.i. The aim of the study was to evaluate the use of scanning electron microscopy (SEM) combined with maceration techniques (2 N NaOH for 1, 3 and 5 days) for a spatial assessment of the interactions between the implanted material and the ingrowing tissue components. Application of 2 N NaOH caused the complete dissolution of the PDS-material and a concomitant gradual disappearance of cellular and amorphous tissue components, thereby unmasking the remaining collageneous network. SEM of non-macerated specimens demonstrated that 21 days p.i. the entire implant has been filled with connective tissue components. Additionally, the ventral and dorsal surfaces of the implant were covered by a collageneous layer (neo-fascia). 21 days p.i. the PDS-filaments had developed minor clefts, which increased in number and depth 42 days p.i., and were transformed into small remnants 180 days p.i. Alkali treatment revealed the three-dimensional arrangement of collagen fibers, which ensheathed the PDS-filaments and formed interconnecting networks between them. At the ventral portion of the implant the fibrous network was more elaborate and densely distributed. 180 days p.i. the implant has been transformed into a membranous structure (neo-membrane) composed of the ventral and dorsal neofascia, remnants of PDS-filaments and a continuous connective tissue layer containing wave-like collagenous structures. Whereas 21 and 42 days p.i. no herniation was observed, 130 days p.i. the implant began to bulge out of the ventral abdominal wall. It is therefore concluded that inspite of the advantages of absorbable materials, longer resorption times may be required to allow a sufficient consolidation of the ingrowing connective tissue to resist the tensile forces of the abdominal muscle coat. SEM combined with 2N NaOH maceration proved to be a usefull tool in addition to conventional histological techniques for a three-dimensional assessment of fibrous connective tissue components ingrowing into alloplastic implants.

Abdominal Muscles↗

High-resolution solid-state (13)C NMR studies of chemisorbed organometallics. Chemisorptive formation of cation-like and alkylidene organotantalum complexes on high surface area inorganic oxides.

(13)C CPMAS NMR spectroscopy has been employed to investigate the surface chemistry of the organotantalum hydrocarbyl/alkylidene complexes, Cp'Ta((13)CH(3))(4) (1*), Cp(2)Ta((13)CH(3))(3) (2*), Cp(2)Ta((13)CH(2))((13)CH(3)) (3*), and Ta((13)CH(t)Bu)((13)CH(2)(t)Bu)(3) (4*) [Cp' = eta(5)-(CH(3))(5)C(5), Cp = eta(5)-C(5)H(5)] supported on partially dehydroxylated silica (PDS), dehydroxylated silica (DS), or dehydroxylated gamma-alumina (DA). Mono-Cp tantalum hydrocarbyl 1* undergoes chemisorption to form Cp'Ta((13)CH(3))(3)O-Si mu-oxo species on silica, and "cation-like" Cp'Ta((13)CH(3))(3)(+) and Cp'Ta((13)CH(3))(3)O-Al mu-oxo species on DA, via pathways analogous to those established for organo-group 4 and actinide complexes. When supported on DA, bis-Cp tantalum hydrocarbyl 2* follows the same chemisorption mode as 1*. However, when 2* is chemisorbed on PDS and DS, a "cation-like" Cp(2)Ta((13)CH(3))(2)(+) species is the major adsorbate product. On PDS, bis-Cp tantalum alkylidene complex 3* is converted predominantly to a stable "cation-like" Cp(2)Ta((13)CH(3))(2)(+) species, presumably via electrophilic addition of a proton from the PDS surface. In contrast to 3*, Ta alkylidene complex 4* forms predominantly a Ta((13)CH(t)Bu)((13)CH(2)(t)Bu)(2)O-Si, mu-oxo-alkylidene species on PDS.

Journal Article↗

Internal consistency, intercriterion overlap and diagnostic efficiency of criteria sets for DSM-IV schizotypal, borderline, avoidant and obsessive-compulsive personality disorders.

OBJECTIVE: To evaluate performance characteristics of DSM-IV Personality Disorders (PDs) criteria. METHOD: Six hundred and sixty-eight adults recruited for the Collaborative Longitudinal Personality Disorders Study (CLPS) were assessed with diagnostic interviews. RESULTS: Within-category inter-relatedness was evaluated by Cronbach's alpha and median intercriterion correlations (MIC). Cronbach's alpha ranged from 0.47 to 0.87 (median=0.71); seven of the 10 PDs had alphas greater than 0.70. Between-category criterion overlap was evaluated by "inter-category" intercriterion correlations between all PD pairs (ICMIC). ICMIC values (median=0.08) were lower than MIC values (median=0.23). Diagnostic efficiency statistics (sensitivity, specificity, positive predictive power and negative predictive power were calculated for schizotypal, borderline, avoidant and obsessive-compulsive PDs. CONCLUSION: DSM-IV PD criteria sets have some convergent validity and discriminant validity: criteria for individual PDs correlate better with each other than with criteria for other PDs. Diagnostic efficiency statistics provide guidance regarding usefulness of criteria for inclusion or exclusion.

Adolescent↗

Recent life events preceding suicide attempts in a personality disorder sample: findings from the collaborative longitudinal personality disorders study.

Few studies have examined the relationship between life events, suicide attempts, and personality disorders (PDs), in spite of the strong associations between PDs and suicidal behavior, and the poor coping strategies often exhibited by these individuals. The authors examined whether participants with PDs who attempted suicide during the first 3 years of a prospective, longitudinal study were more likely to experience specific life events in the month during and preceding the suicide attempt. Of 489 participants with PDs, 61 attempted suicide during the 3-year, follow-up interval. Results indicated that negative life events, particularly those pertaining to love-marriage or crime-legal matters, were significant predictors of suicide attempts, even after controlling for baseline diagnoses of borderline PD, major depressive disorders, substance use disorders, and a history of childhood sexual abuse. Therefore, certain types of negative life events are unique risk factors for imminent suicide attempts among individuals with PDs.

Adult↗

Are personality disorder criteria ethnically biased? A card-sort analysis.

On the basis of methodology used in previous research on sex criterion bias, this study examined ethnicity criterion bias of personality disorders (PDs) defined in the Diagnostic and Statistical Manual of Mental Disorders (3rd ed., Rev.) and included examination of sex as well as ethnicity. A card-sort analysis using undergraduate college students as sorters indicated that criteria for all of the PDs were applied disproportionately by ethnicity, resulting in particular ethnic groups receiving diagnoses for specific PDs. Criteria were sorted systematically such that diagnoses of antisocial and paranoid PDs were assigned to African Americans, schizoid PD was assigned to Asian Americans, and schizotypal PD was assigned to Native Americans. All other PDs were assigned to European Americans, whereas none of the criteria were sorted resulting in any PD diagnosis being applied to Latinos. Implications for clinicians, methodological considerations, and recommendations for future research are discussed.

Adult↗

Positron emission tomography displacement sensitivity: predicting binding potential change for positron emission tomography tracers based on their kinetic characteristics.

There is great interest in positron emission tomography (PET) as a noninvasive assay of fluctuations in synaptic neurotransmitter levels, but questions remain regarding the optimal choice of tracer for such a task. A mathematical method is proposed for predicting the utility of any PET tracer as a detector of changes in the concentration of an endogenous competitor via displacement of the tracer (a.k.a., its 'vulnerability' to competition). The method is based on earlier theoretical work by Endres and Carson and by the authors. A tracer-specific predictor, the PET Displacement Sensitivity (PDS), is calculated from compartmental model simulations of the uptake and retention of dopaminergic radiotracers in the presence of transient elevations of dopamine (DA). The PDS predicts the change in binding potential (DeltaBP) for a given change in receptor occupancy because of binding by the endogenous competitor. Simulations were performed using estimates of tracer kinetic parameters derived from the literature. For D(2)/D(3) tracers, the calculated PDS indices suggest a rank order for sensitivity to displacement by DA as follows: raclopride (highest sensitivity), followed by fallypride, FESP, FLB, NMSP, and epidepride (lowest). Although the PDS takes into account the affinity constant for the tracer at the binding site, its predictive value cannot be matched by either a single equilibrium constant, or by any one rate constant of the model. Values for DeltaBP have been derived from published studies that employed comparable displacement paradigms with amphetamine and a D(2)/D(3) tracer. The values are in good agreement with the PDS-predicted rank order of sensitivity to displacement.

Binding, Competitive↗

The use of polydimethylsiloxane in the treatment of incontinence after radical prostatectomy.

OBJECTIVE: To report the results of transurethral submucosal injection therapy of polydimethylsiloxane (PDS) to treat incontinence after radical prostatectomy (RP). PATIENTS AND METHODS: Since 1993, about 80 retropubic RPs have been carried out at our institution each year. Severe post-operative incontinence occurred in six patients, with a mean duration of incontinence after RP of 28 months. The pre-operative evaluation consisted of cysto-urethroscopy and urodynamics. Because we have no experience with artificial sphincter implantation, transurethral injection therapy was used to treat the post-operative incontinence, using PDS (vulcanized silicone rubber particles). This material has a mean particle size of 188 microns, providing stability of the material at the injection site. The six patients with severe post-operative incontinence were treated using injection therapy with PDS. RESULTS: After a mean follow up of 15.5 months, five patients, who suffered from day and night incontinence and required at least five pads per day, were dry after injection therapy. One patient improved significantly but still required two pads during the day, but was continent during the night; three patients required a second injection. A mean of 7.5 mL of PDS was used per patient and the side-effects of therapy (dysuria and urinary retention) were minimal. CONCLUSION: Because PDS has excellent biocompatibility, few side-effects or complications, transurethral injection therapy using silicone particles is a justifiable procedure for treating incontinence after RP.

Dimethylpolysiloxanes↗

Optimization of stacked half-hitch knots for arthroscopic surgery.

PURPOSE: This study was conducted to determine the optimal configuration of stacked half-hitch knots that would give the maximum knot-holding capacity (KHC). TYPE OF STUDY: Mechanical testing study. METHODS: The 2 types of suture materials tested were No. 1 PDS II monofilament and No. 2 Ethibond braided (Ethicon, Somerville, NJ) because these are the 2 most commonly used sutures in arthroscopic surgery. Twelve configurations of stacked half-hitch knots including 2 versions of the Revo knot were tested. Knots were tied between 2 steel hooks 7 mm apart on a manual knot-testing machine. The steel hooks were spread apart to break the knot and the KHC was determined by the peak load recorded on the digital force transducer. Maximum KHC was achieved for No. 1 PDS II sutures by locking the knot with 2 RHAPs (reversing half-hitch on alternate post) and, for No. 2 Ethibond sutures, by locking the knot with 3 RHAPs. Because of the possibility of PDS II sutures unraveling, it is recommended for both No. 1 PDS II and No. 2 Ethibond sutures, that all stacked half-hitches be locked with 3 RHAPs. By adding 1 RHAP to the Revo knot, failure by slippage can be eliminated. RESULTS: The recommended knots tied with braided No. 2 Ethibond sutures were 1.5 times stronger than knots tied with No. 1 PDS II sutures. Although there was variability in the KHC of the recommended knots tied by different surgeons using different knot tiers, the greatest difference in the mean KHC was less than 10%. CONCLUSIONS: Stacked half-hitch knots locked with 3 RHAPs are unlikely to fail by slippage.

Arthroscopy↗

Consideration of perfusion reserve in viability assessment by myocardial Tl-201 rest-redistribution SPECT: a quantitative study with dual-isotope SPECT.

BACKGROUND: To optimize the use of thallium 201 rest-redistribution study in Tl-201/technetium 99m sestamibi dual-isotope single photon emission computed tomography (SPECT), the predictability of Tl-201 rest-redistribution for viable myocardium was examined according to the degree of perfusion reserve. METHODS AND RESULTS: Twenty patients with both unstable angina and left ventricular dysfunction were enrolled. Tl-201 rest-dipyridamole stress Tc-99m sestamibi gated SPECT/Tl-201 24-hour redistribution SPECT was performed before and 3 months after coronary artery bypass grafting. Through use of a 20-segment model, segmental stress perfusion, rest perfusion, and systolic thickening were quantified on gated SPECT by means of automatic quantitation software. Perfusion was expressed as the average percentage of maximal radioactivity uptake. To represent perfusion reserve, the perfusion difference score (PDS) was defined as rest perfusion minus stress perfusion. A low PDS indicated little or no inducible ischemia, and a high PDS indicated inducible ischemia. In dysfunctional myocardium, viability was defined by the improvement of thickening after coronary artery bypass grafting. The overall predictability of Tl-201 redistribution for viability was 0.709 of the area under the curve (AUC) in receiver operating characteristic analysis. With a cutoff of 7, predictability was significantly better in the low PDS group (AUC = 0.785) than in the high PDS group (AUC = 0.582). CONCLUSIONS: The predictability of Tl-201 rest-redistribution for viability differs according to perfusion reserve. It was more reliable for dysfunctional myocardium with persistent perfusion decrease. On the basis of the continuum hypothesis of chronic stunning and hibernation, we suggest that dysfunctional myocardium with persistent perfusion decrease should be assessed by Tl-201 redistribution SPECT.

Aged↗

A single polypeptide catalyzing the conversion of phytoene to zeta-carotene is transcriptionally regulated during tomato fruit ripening.

The cDNA of the gene pds from tomato, encoding the carotenoid biosynthesis enzyme phytoene desaturase, was cloned, and its nucleotide sequence was determined. Cells of Escherichia coli that expressed the tomato pds gene could convert phytoene to zeta-carotene. This result suggests that one polypeptide, the product of the pds gene, can carry out phytoene desaturation in the carotenoid biosynthetic pathway. Transcripts of the pds gene accumulate in orange tomato fruit, indicating transcriptional control of pds expression during fruit ripening. The deduced amino acid sequence of phytoene desaturase indicates that this enzyme in tomato contains 583 amino acids that are highly conserved with respect to the homologous enzymes in cyanobacteria and algae. The deduced amino acid sequences of the phytoene desaturases from other microorganisms (purple bacteria and fungi) appear to be evolutionarily unrelated to those from green photosynthetic organisms.

Amino Acid Sequence↗

Cytoplasmic inhibition of carotenoid biosynthesis with virus-derived RNA.

The carotenoid biosynthetic pathway in higher plants was manipulated by using an RNA viral vector. A cDNA encoding phytoene synthase and a partial cDNA encoding phytoene desaturase (PDS) were placed under the transcriptional control of a tobamovirus subgenomic promoter. One to two weeks after inoculation, systemically infected Nicotiana benthamiana plants were analyzed for phytoene. Leaves from transfected plants expressing phytoene synthase developed a bright orange phenotype and accumulated high levels of phytoene. Cytoplasmic inhibition of plant gene expression by viral RNA was demonstrated with an antisense RNA transcript to a partial PDS cDNA derived from tomato. The leaves of the plants transfected with the antisense PDS sequence developed a white phenotype and also accumulated high levels of phytoene. A partial cDNA to the corresponding N. benthamiana PDS gene was isolated and found to share significant homology with the tomato antisense PDS transcript. This work demonstrates that an episomal RNA viral vector can be used to deliberately manipulate a major, eukaryotic biosynthetic pathway. In addition, our results indicate that an antisense transcript generated in the cytoplasm of a plant cell can turn off endogenous gene expression.

Amino Acid Sequence↗

Quantitative effects of pelleting on performance, gastrointestinal tract and behaviour of meat-type chickens.

1. In an attempt to quantify the effects of "degree" of pelleting, two experiments were conducted. Diets were prepared by mixing together a mash composed mainly of maize (experiment 1) or sorghum (experiment 2) with soft pellets, or soft pellets mixed with hard pellets. 2. The pelleting degrees (PDs) were as follows: 0 mash; 0.5 mixture of soft pellets and mash 1 to 1; 1 soft pellets pelleted once; 1.5 mixture of soft and hard pellets 1 to 1; 2 hard pellets pelleted twice. 3. In experiment 2, the weight and length of the digestive organs were determined as well as digestive enzyme activities. In both experiments, the behaviour recorded was eating, standing, sitting and drinking. 4. Food intake and body weight gain were related to the degree of pelleting in a curvilinear manner. PD had a positive effect up to a peak (1 to 1.5 PD), after which its effect decreased. Food efficiency was not related to PD. In experiment 1, food efficiency of PDs 1 to 2 were superior to PDs 0 to 0.5 and in experiment 2, PDs 1.5 to 2 were superior to PD 0. 5. The relative weight of the gizzard was reduced by pelleting, whereas pelleting increased the relative weight of abdominal fat. The content of the crop was not affected by PD, whereas that of the proventriculus was lowest in the PD 2 group. Gizzard content was inversely related to PD. Pelleting reduced the length of the jejunum and ileum: which were shortened by about 15% with PDs 1 to 2, as compared to PD 0. The weight/length ratio of the jejunum and ileum tended to increase with increasing PD to a peak at PD 1.5, and to decrease thereafter. 6. Trypsin activity in the pancreas and amylase activity in the intestinal content were reduced by pelleting. 7. Chicks fed pelleted diets were less active: they 'sat' more and spent less time eating than their mash-fed counterparts.

Adipose Tissue↗

Differential induction of hepatic microsomal epoxide hydrolase by alkyl sulphides and alkyl ethers in rat.

1. Previous studies have shown that the expression of certain cytochromes P450 and major glutathione S-transferases (GSTs) is differentially modulated by alkyl sulphide treatment. The current study was designed to examine the influence of several alkyl sulphides and alkyl ethers on the induction of hepatic microsomal epoxide hydrolase (mEH) in rat. 2. Northern blot analysis has shown that treatment of rats with allyl disulphide (ADS) or allyl sulphide (AS) (50 mg/kg/day, 7 days) resulted in 5-6-fold increases in mEH mRNA levels, whereas allyl ether failed to stimulate mEH gene expression. Rats treated with propyl disulphide (PDS) or propyl sulphide (PS) exhibited increases in mEH mRNA levels, although the relative increases were less than those produced by ADS or AS. Propyl ether failed to increase hepatic mEH mRNA levels. Immunoblot analyses confirmed that allyl and propyl sulphides induce hepatic mEH protein, with the agents containing allyl moiety being more effective. 3. Treatment of rats with ADS at 100 mg/kg resulted in 9-14-fold increases in mEH mRNA levels at 12 and 24 h post-treatment respectively, whereas AS caused a maximal increase at the 24-h time point. Animals treated with PDS or PS exhibited time-related increases in mEH mRNA levels, resulting in 2-6-fold elevations at 72-h post-treatment. The changes in mEH mRNA levels after ADS or AS treatment appeared to be more rapid than those after PDS or PS. The rank order for increases in mEH mRNA levels was ADS > AS > PS > PDS. The result of immunoblot analysis was consistent with that of Northern blot analysis. 4. Rats treated with isopropyl sulphide (IPS), butyl sulphone, tert-butyl sulphide, sec-butyl sulphide or butyl sulphide (100 mg/kg/day) showed 3-5-fold increases in the mEH mRNA levels at 3 days post-treatment. IPS treatment caused a similar increase in the mRNA level to that of PS, whereas the induction efficacy of PDS was lower than that of PS or IPS. Treatment with butyl sulphone as well as the structural isomers of butyl sulphides caused approximately 3-fold elevations in mEH mRNA levels. 5. These results provide evidence that alkyl sulphides, but not alkyl ethers, are capable of increasing mEH mRNA levels and that the organosulphur compounds with the allyl moiety are more effective in stimulating the mEH gene than are saturated alkyl sulphides. The comparable increase in mEH mRNA by butyl sulphone as well as the necessity of sulphur atom suggests that sulphone metabolites from the alkyl sulphides might be the ultimate inducers of mEH.

Allyl Compounds↗