Matter-Driven Change of Spacetime Topology.

Using Monte Carlo computer simulations, we study the impact of matter fields on the geometry of a typical quantum universe in the causal dynamical triangulations (cdt) model of lattice quantum gravity. The quantum universe has the size of a few Planck lengths and the spatial topology of a three-torus. The matter fields are multicomponent scalar fields taking values in a torus with circumference δ in each spatial direction, which acts as a new parameter in the cdt model. Changing δ, we observe a phase transition caused by the scalar field. This discovery may have important consequences for quantum universes with nontrivial topology, since the phase transition can change the topology to a simply connected one.

Importance of chewing, saliva, and swallowing function in patients with advanced oral cancer undergoing preoperative chemoradiotherapy: a prospective study of quality of life.

The primary objective of this study was to investigate the quality of life (QOL) of patients with oral squamous cell carcinoma (OSCC) undergoing curative neoadjuvant chemoradiotherapy followed by radical tumour resection and simultaneous oral cavity reconstruction, using two validated questionnaires. A secondary objective was to assess clinical variables predicting post-treatment dysfunction in chewing, saliva, and swallowing. Thirty-five patients with locally advanced OSCC who underwent preoperative chemoradiotherapy were recruited prospectively. All patients completed both the University of Washington Quality of Life version 4 questionnaire (UW-QOL) and the Functional Assessment of Cancer Therapy-Head & Neck version 4 questionnaire (FACT-H&N). UW-QOL and FACT-H&N items were associated with clinical variables. Nearly three-quarters of OSCC patients perceived good to excellent levels of overall QOL after preoperative chemoradiotherapy. Chewing difficulties, decreased salivary function, and swallowing dysfunction were the most frequent complaints of OSCC patients. Items related to food intake were significantly worse in OSCC patients older than 60 years and those with T4 tumours, as well as those without alcohol intake. Chewing, saliva, and swallowing are the most significant issues in patients with OSCC undergoing preoperative chemoradiotherapy. The results of this study may help guide treatment decisions for OSCC patients based on more accurate expectations of adverse effects of cancer treatment.

Finite element analysis of stress distributions in mono- and bi-cortical dental implants.

The finite element analysis (FEA) of the stress distribution in the mono- and bicortically fixed implants subjected to 3-axial loading was performed and verified experimentally on a model mandible to evaluate the benefits of each type of fixation from the viewpoint of the compressive stress reduction in the cortical part of atrophied mandible. The analysis revealed that the highest compressive stresses in the cortical bone are generated at the edge of the cortical bone where the highest torque from the implant is acting. The most effective way to reduce the maximum level of compressive stresses in the cortical bone and in the implant is the recession of the implant thread slightly below the surface of the cortical bone. Shortening of the intraosseal length of the implant and/or thinning of the upper cortical bone result in a substantial increase of the maximum compressive stresses. The comparison of FEA and model experiments suggests that bicortical fixation is the most efficient in the fresh implants and the advantage of bicortical fixation compared to monocortical fixation decreases with time due to osteointegration, possibly as a result of gradual suppression of sliding between the bone and implant during loading.

Bilateral sagittal split osteotomy and temporomandibular disorders: rigid fixation versus wire fixation.

OBJECTIVE: The effects of orthognathic surgery on temporomandibular disorders may be related to the surgical method that is used. Specifically, it has been suggested that the choice of stabilization technique may play a major role in the functional outcome of mandibular advancement surgery. The purpose of this study was to prospectively compare long-term (2 years) signs and symptoms of temporomandibular disorders after orthognathic surgery with bilateral sagittal split osteotomy in 127 patients randomized to receive rigid or wire fixation. STUDY DESIGN: Signs and symptoms of temporomandibular disorders were evaluated before and 2 years after surgery by means of the overall craniomandibular index (CMI), dysfunction index (DI), and muscle index (MI). Patients also reported subjective symptoms of temporomandibular disorders by marking areas of pain on a standard drawing of the head and rating the pain in each area on a scale ranging from 1 (very mild) to 7 (very extreme). Subjective pain was also assessed through use of the Oral Health Status Questionnaire and by a rating of the difficulty in opening the mouth because of pain. RESULTS: There were no statistically significant differences in the CMI, MI, or DI change scores between the wire and rigid fixation groups (mean CMI(wire) = 0.05, mean CMI(rigid) = 0.04; mean DI(wire) = 0.02, mean DI(rigid) = 0. 01; mean MI(wire) = 0.08, mean MI(rigid) = 0.08) 2 years after surgery. Temporomandibular joint sounds also demonstrated no significant differences between the two fixation methods. Subjective pain reports were consistent with the clinical examinations. On average, both wire and rigid scores decreased slightly, but the change scores were not significantly different between groups. CONCLUSIONS: These findings suggest that the long-term (2 years) effects of wire and rigid internal fixation methods on the signs and symptoms of temporomandibular disorders do not differ. Earlier concerns about increased risk for temporomandibular disorders with rigid fixation were not supported by these results.

Pain relief following day case laparoscopic tubal ligation with intra-peritoneal ropivacaine: a randomised double blind control study.

The aim of this study was to examine the effectiveness of ropivacaine administered by a simple intraperitoneal technique in relieving pain following laparoscopic application of Filshie clips. Nineteen patients were randomised to receive either ropivacaine (200 mg) or normal saline through the umbilical port following clip application. Using a visual analogue scale women receiving ropivacaine had significantly lower pain scores 2 hours post operatively (0.97 vs 2.03 p < 0.05). The mean total postoperative fentanyl use was also significantly lower on the ropivacaine group (40 microg vs 104 microg p < 0.02). Only 10% (1/10) of the women in the ropivacaine group complained of nausea compared with 44% (4/9) in the control group. Furthermore, 80% (8/10) of women in the ropivacaine group were either very or totally satisfied with their pain relief. Only 56% (5/9) of the women in the control group were very or totally satisfied with their pain relief. Ropivacaine administered by a simple intraperitoneal technique following laparoscopic sterilisation significantly reduces postoperative pain and parenteral analgesic requirements. It would be reasonable to consider this method as standard practice following laparoscopic tubal ligation.

Effects of major Class II occlusal corrections on temporomandibular signs and symptoms.

This study explored the relationship between malocclusion and signs and symptoms of temporomandibular disorders (TMD) in 124 patients with severe Class II malocclusion, before and 2 years after bilateral sagittal split osteotomy (BSSO). Patients were evaluated with the Craniomandibular Index (CMI), the Peer Assessment Rating Index (PAR Index, to assess gross changes in the occlusion), and symptom questionnaires. The results showed a significant improvement in occlusion; PAR Index scores dropped from a mean of 18.1 before surgery to a mean of 6.1 at 2 years postsurgery (P < 0.001). The CMI and masticatory index (MI) for muscle pain indicated clinically small but statistically significant improvement (P = 0.0001) from before surgery (mean CMI = 0.14, mean MI = 0.15) to after surgery (mean CMI = 0.10, mean MI = 0.08). The number of patients with clicking upon opening decreased significantly from 33 (26.6%) to 13 (10.5%) (P = 0.001). However, the number of patients with fine crepitus increased from 5 (4.0%) before surgery to 16 (12.9%) at 2 years postsurgery (P = 0.005). Significant reductions in subjective pain and discomfort were also found 2 years after surgery. The magnitude of change in muscular pain was not related to the severity of the pretreatment malocclusion, a finding that suggests that factors other than malocclusion may be responsible for the change in TMD.

Ultrasound in the evaluation of an unusual periarticular soft tissue tuberculosis.

This case report describes a 19-year-old patient with a swelling of the interphalangeal joint of the left thumb. Conventional radiography revealed erosive changes and a periarticular osteopenia. A marked increase in bone turnover of the entire thumb and wrist region was confirmed scintigraphically. Repeated attempts at arthrocentesis were unsuccessful. By ultrasonography, using a linear 7.5-Mhz transducer, a hypoechoic area with an anechoic core was located within the soft tissue swelling dorsal of the diaphysis of the proximal phalanx of the thumb. An aspiration of this anechoic area was possible and cytological analysis revealed an exudate with about equal percentages of lymphocytic/monocytic and polymorphonuclear cells and the microscopic and cultural detection of Mycobacterium tuberculosis. Ultrasonography is less expensive than MRI and may offer an important adjunct to evaluation of soft tissue problems.

NMR monitoring of rheumatoid arthritis patients receiving anti-TNF-alpha monoclonal antibody therapy.

The aim of this study was to investigate if dynamic gadolinium-DTPA-supported magnetic resonance (MR) imaging can monitor the therapeutic effect of a fast-acting immuno-modulating drug like anti-tumour necrosis factor alpha (anti-TNF-alpha) monoclonal antibody (moab) in patients with rheumatoid arthritis (RA). Dynamic MR imaging was performed on 64 joints in a total of 18 patients before and after infusion with either a placebo or 1 or 10 mg/kg of anti-TNF-alpha moab. Additionally, treating the placebo group and reinfusing the verum group with either 3 or 10 mg/kg was monitored by quantitative nuclear magnetic resonance (NMR). Time-dependent signal intensity changes were then correlated with a total of five Paulus criteria and with ESR and C-reactive protein (CRP). No changes in either the gadolinium uptake or clinical parameters were seen after the infusion of a placebo. Therapy with 1 mg/kg anti-TNF-alpha moab resulted in a significant decrease in clinical disease activity, as well as in gadolinium-DTPA uptake in dynamic NMR studies. However, correlations between singal intensity changes and Paulus criteria were only demonstrated for the variable "doctor's evaluation of disease activity". Patients given 10 mg/kg moab demonstrated a very significant improvement in all clinical manifestations of their disease, as well as a high significant reduction in gadolinium uptake (P = 0.004). In addition, the latter group showed significant correlations between time-dependent signal intensity changes and five Paulus criteria: "number of swollen joints", "number of painful joints", "duration of morning stiffness", "doctor's evaluation of disease activity" and "patient's evaluation of disease activity". No differences and correlations were seen for ESR and CRP. We concluded that dynamic NMR studies are suitable to monitor inflammatory activity in RA patients under therapy with biological response modifiers such as anti-TNF-alpha moab.

Color Doppler imaging versus phlebography in the diagnosis of deep leg and pelvic vein thrombosis.

The objective of this prospective study was to evaluate the accuracy of color Doppler imaging in comparison to phlebography in diagnosing phlebothrombosis. Five hundred and twenty-six phlebographies (reference method) were compared with 526 color Doppler sonographic examinations. Thrombosis diagnosed with color Doppler imaging showed a sensitivity of 98.0% (400 of 408). In 91.6% (482 of 526) of all examinations the extent of the thrombosis diagnosed with phlebography could also be seen with color Doppler imaging. When the clinical situation is unclear, color Doppler imaging should precede phlebography. Only when findings with ultrasonography are questionable should phlebography definitely be considered.

Modulation of buccal pressure during prey capture in Hexagrammos decagrammus (Teleostei: Hexagrammidae)

Changes in intraoral pressure during prey capture were recorded for a trophic generalist, Hexagrammos decagrammus, feeding on different prey species. Prey were grouped into elusive (shrimps), grasping (isopods and crabs) and non-elusive (pieces of shrimp) categories. Elusive and grasping prey elicited strikes with a larger and faster reduction in buccal pressure than did non-elusive prey. The suction force generated by the predator differed for strikes among the shrimp genera in the elusive prey category. The most sedentary shrimps (Crangon alaskensis and C. nigricauda) elicited the fastest and greatest reduction in pressure relative to the most evasive shrimps (Pandalus danae and Heptacarpus stylus). A preparatory phase, during which the buccal cavity is compressed prior to the strike, occurred significantly more frequently in strikes at grasping prey than in strikes at elusive and non-elusive prey, and more frequently for elusive than for non-elusive prey. Prey size did not influence the suction force generated by the predator. No differences in buccal pressure patterns were detected between strikes that resulted in a capture or a miss, suggesting that misses were due to the escape behavior of the prey and were not the result of an inappropriate suction force. These data support the current view that fish can modify their feeding mode in response to prey behavior, and they emphasize that the behavioral responses of the individual prey must be considered when defining the appropriate strategy for prey capture. The use of a flexible, modifiable feeding behavior is associated with a broad diet in H. decagrammus and may increase capture success on diverse prey relative to that of other species showing stereotypical feeding responses.

Modulation of attack behavior and its effect on feeding performance in a trophic generalist fish,

This study examines the ability of a temperate marine fish, Hexagrammos decagrammus, to modulate its prey capture behavior in response to differences in prey type. This species has an extremely broad diet, feeding on prey which demonstrate very different anti-capture behaviors. Video-taped attacks on three shrimp species, one crab and pieces of shrimp were analyzed to determine the relative contributions of suction-feeding and ram-feeding behaviors to prey capture. The prey capture behaviors used by the predator were related to differences in escape behavior among the three shrimp species. H. decagrammus used behaviors characteristic of other ram-feeding predators when feeding on the two most elusive shrimp species: high attack velocity, attack initiated at a greater distance from the prey, and greater movement of the predator relative to the prey. Strikes at crabs and pieces of shrimp elicited strikes more typical of other suction-feeding predators, with lower attack velocities, shorter initial predator­prey distances and greater relative movement of the prey towards the predator. Attacks on the least elusive shrimp species showed elements of both ram and suction feeding. Modulation of attack velocity increased capture success on elusive prey, supporting the hypothesis that diet diversity is associated with the presence of a repertoire of feeding behaviors. These data suggest that functional differences in prey anti-capture behavior, as well as the functional versatility of the predator, must be addressed in ecomorphological studies that try to correlate predator morphology with diet.

A no bleed implant.

Breast implants have evolved from the original saline-filled, smooth-surfaced silicone rubber bag to silicone gel-filled smooth-walled sacs to a combination of a silicone gel-filled bag within a saline-filled sac, and, most recently, a reversed, double-lumen implant with a saline bag inside of a gel-filled bag. Texture-surfaced implants were first used in 1970 when the standard silicone gel-filled implant was covered with a polyurethane foam. Because of concerns about the degradation products of this foam, they were removed from the market in 1991. In 1975 double-lumen silicone textured implants were developed, followed by silicone gel-filled textured implants. In 1990 a new radiolucent, biocompatible gel was produced that reduced the problem of radioopacity of silicone implants. Because of the gel's sufficiently low coefficient of friction, leakage caused by fold flaw fracture may also be decreased. We present a case where this new biocompatible gel implant was repositioned after four months. The resulting scar capsule in this soft breast was thin [< 0.002 cm (0.008 in.)] and evenly textured as a mirror image of the textured silicone surface. Scanning electron microscopy and x-ray defraction spectrophotometry revealed no silicone bleed.

Diltiazem and metoclopramide overdose.

A fatality resulting from the suicidal ingestion of diltiazem and metoclopramide is described. The decedent was a 25-year-old female with a history of alcoholism and cocaine abuse who overdosed on her mother's medications. On admission she was bradycardiac with severe hypotension and third-degree heart block which progressed to asystole. She was resuscitated but remained comatose until her death four days later. Serum samples from the first 15 h of hospitalization were analyzed for diltiazem and metoclopramide by gas chromatography with nitrogen-phosphorus detection. Diltiazem levels 1 hour post admission were 8.49 mg/L. Diltiazem elimination followed zero-order kinetics with an elimination rate of 0.68 mg/L/h. Metoclopramide levels 1 hour post admission were 4.4 mg/L. Data indicated a biphasic elimination curve for metoclopramide with an initial half-life of 1.3 h and a terminal half-life of 20 h.

Bioactivation mechanism of cytotoxic homocysteine S-conjugates.

S-(1,2-Dichlorovinyl)-L-homocysteine is a much more potent nephrotoxin than the corresponding cysteine S-conjugate S-(1,2-dichlorovinyl)-L-cysteine (A. A. Elfarra, L. H. Lash, and M. W. Anders (1986) Proc. Natl. Acad. Sci. USA 83, 2667-2671). The objective of the present experiments was to test the hypothesis that the increased toxicity of homocysteine S-conjugates may be associated with the formation of the reactive metabolite 2-oxo-3-butenoic acid, which may arise via a nonenzymatic retro-Michael elimination reaction from the 2-oxo acid metabolites of homocysteine S-conjugates. S-(2-Benzothiazolyl)-L-homocysteine, which was a substrate for purified bovine kidney cysteine conjugate beta-lyase (glutamine transaminase K) and whose metabolism was dependent on the presence of a 2-oxo acid, was cytotoxic in isolated rat kidney cells and was toxic to rat renal mitochondria, whereas the cysteine S-conjugate S-(2-benzothiazolyl)-L-cysteine had little effect. L-Methionine sulfoximine, L-canavanine, and the Michael acceptor methyl vinyl ketone were cytotoxic. The 2-hydroxy acid analogs of S-(1,2-dichlorovinyl)-L-homocysteine and 2-oxo-3-butenoic acid, S-(1,2-dichlorovinyl)-2-hydroxy-4-mercaptobutanoic acid and 2-hydroxy-3-butenoic acid, respectively, which are expected to be metabolized by rat renal L-2-hydroxy (L-amino) acid oxidase to yield 2-oxo-3-butenoic acid, were also cytotoxic. To obtain evidence for the formation of 2-oxo-3-butenoic acid as a product of the metabolism of L-homocysteine S-conjugates and analogs, trapping experiments were conducted. S-(2-Benzothiazolyl)-L-homocysteine, S-(1,2-dichlorovinyl)-L-homocysteine, L-methionine sulfoximine, and L-canavanine were converted by snake venom L-amino acid oxidase to 2-oxo-3-butenoic acid, which was trapped by the nucleophile methanethiol to yield 4-methylthio-2-oxobutanoic acid; the trapped product was derivatized with 2,4-dinitrophenylhydrazine and was identified by its electronic absorption spectrum and by high-performance liquid chromatography. Similar trapping experiments conducted with kidney homogenates and purified beta-lyase were not successful. The data indicate that the bioactivation of homocysteine S-conjugates and analogs involves the enzymatic formation of the corresponding 2-oxo acids followed by a nonenzymatic retro-Michael elimination reaction to yield the Michael acceptor 2-oxo-3-butenoic acid, which may contribute to the observed cytotoxicity of homocysteine S-conjugates.

Immunosuppression of mice by delta-9-tetrahydrocannabinol.

Studies were initiated to determine the effects of delta-9-tetrahydrocannibinol (THC) on the production of indirect IgG plaque-forming and rosette-forming cells in mice. BDF1 mice were immunized with sheep erythrocytes followed by multiple injections of 10, 25 or 40 mg/kg THC. Results indicated that both parameters were significantly reduced by 25 mg/kg, thus affirming the immunosuppressive properties of this substance in mice.

[Serum lipids in uterine cancer]. / Lipidy syvorotki krovi u bol'nykh rakom matki.

In 40 patients with uterine cancer changes were studied in total lipids, beta-lipoproteids and cholesterol in serum prior to, during and 4 years following the treatment. All patients were characterized by a low level of total lipids and increased cholesterol values, the former were normalized under the influence of the therapy in disappearance of the symptoms. The level of beta-lipoproteids decreased prior to the treatment was reliably increased during it only in patients with cervical cancer subjected to the combination treatment (surgery & irradiation).