Fracture resistance and mode of failure of various types of root filled teeth.

AIM: To investigate ex vivo the influence of the post system on fracture resistance and failure mode of root filled incisor, canine, premolar and molar teeth. METHODOLOGY: Eighty human teeth were divided into eight groups (n = 10) resulting from the interaction between the two study factors: post system (glass fibre post; cast Ni-Cr alloy post and core) and type of tooth (maxillary incisors, maxillary canines, maxillary premolars and mandibular molars). All roots were prepared with a 2-mm ferrule and restored with metal crown. Fracture resistance (N) was assessed in a mechanical testing device, and the data were analysed by two-way anova (4 × 2) followed by Tukey's test (α = 0.05). The failure mode was evaluated using an optical stereomicroscope and classified according to the location of the failure. Failure mode data were analysed by two-factor anova and Student-Newman-Keuls (SNK) tests (α = 0.05). Correlation between fracture resistance and failure mode was analysed by linear regression. RESULTS: Glass fibre and cast posts and cores had similar fracture resistance, regardless of the type of tooth. Canines and molars had significantly higher fracture resistance (P < 0.001) than premolars. Incisors teeth had significantly lower fracture resistance (P < 0.001) than premolars. The fracture mode for incisors, premolars and molars was more amenable to restoration when the teeth were restored with glass fibre posts. Fracture resistance had no correlation with fracture mode, regardless of the post system and type of tooth analysed. CONCLUSIONS: Post system had no significant effect on fracture resistance, regardless of the type of tooth. The mode of fracture was more restorable with glass fibre posts.

Outbreak of zoonotic cutaneous leishmaniasis with local dissemination in Balkh, Afghanistan.

OBJECTIVES: In Afghanistan zoonotic cutaneous leishmaniasis (CL) due to Leishmania major has been less widely reported than anthroponotic CL due to L. tropica. However, an outbreak of zoonotic CL occurred amongst a group of British soldiers at a military camp near Mazar-e-Sharif in the Balkh province of northern Afghanistan in 2004. METHODS: A study was performed to assess the epidemiology, clinical features, parasitology results, treatment outcomes and environmental health measures associated with this incident. RESULTS: Twenty (17%) of 120 soldiers developed CL due to L. major and the risk of infection increased with the proximity of their accommodation to an area of recently cleared scrub, where many wild rodents were observed. Most cases had features of local dissemination, including secondary lesions from the pseudo-Koebner phenomenon, sporotrichoid lymphatic spread, lymphadenopathy and satellite papules or milia formation around healing lesions. Several cases responded poorly to fluconazole and low dose (10 mg/kg) sodium stibogluconate, which were considered suitable treatments at the time. Environmental health measures at the military camp were found to be deficient. CONCLUSIONS: Zoonotic CL due to L. major is a significant threat for foreign troops based in Balkh, Afghanistan and may present with unusually severe clinical features and be resistant to previously recommended treatments.

Effect of gamma irradiation and restorative material on the biomechanical behaviour of root filled premolars.

AIM: To investigate ex vivo the influence of gamma irradiation therapy and restorative material on fracture resistance, fracture mode and strain of root filled human premolars. METHODOLOGY: Sixty extracted human maxillary premolar teeth were randomly divided into six groups (n = 10) determined by two study factors: (i) restorative materials: sound teeth, root filled teeth restored with composite resin, root filled teeth restored with amalgam; (ii) gamma irradiation: irradiated (subjected to 60 Gy of gamma irradiation in daily increments of 2 Gy) and nonirradiated. For the strain gauge test, two strain gauges per sample were attached on the buccal and palatal cusp surfaces (n = 5). Strain values were recorded during loading of 0-150 N. Fracture resistance (N) was assessed in a mechanical testing machine (n = 10). Strain gauge for each cusp and fracture resistance data were analysed by two-way anova (3 × 2) followed by the Tukey's honestly significant difference test (α = 0.05). The failure mode was evaluated using an optical stereomicroscope and classified according to the location of the failure. RESULTS: Gamma radiation therapy significantly reduced the fracture resistance of intact teeth. The strain was higher for teeth restored with amalgam than for those restored with composite resin. The teeth restored with composite resin had similar strain values to sound teeth. Nonirradiated teeth had more restorable failures than irradiated teeth. CONCLUSIONS: Gamma irradiation significantly reduced fracture resistance and increased cusp strain. The use of composite resin resulted in better biomechanical behaviour than amalgam for restoring root filled teeth whether or not they were submitted to radiotherapy.

The safety of prenatal ultrasound exposure in human studies.

Diagnostic ultrasound use in obstetrics has been growing rapidly to become an integral part of prenatal care today. The high proportion of exposure to prenatal ultrasound highlights the public health significance of routine ultrasound use. A majority of epidemiologic studies tends to support the safety of diagnostic ultrasound use during pregnancy. However, there have been some reports that there may be a relation between prenatal ultrasound exposure and adverse outcome. Some of the reported effects include growth restriction, delayed speech, dyslexia, and non-right-handedness associated with ultrasound exposure. Continued research is needed to evaluate the potential adverse effects of ultrasound exposure during pregnancy. These studies should measure the acoustic output, exposure time, number of exposures per subject, and the timing during the pregnancy when exposure(s) occurred, while controlling for potential confounding variables such as sociodemographic, medical, and obstetric risk factors. We recommend that a new consensus development conference be held to gather the needed data and provide guidelines for the future research needs, as well as respond to the rapid advances in this technology.

Detection of Bordetella pertussis in clinical specimens by PCR and a microtiter plate-based DNA hybridization assay.

In order to improve detection of Bordetella pertussis in nasopharyngeal aspirates (NPAs) in our laboratory, a PCR-based assay was optimized, and a study was designed (i) to compare results obtained by PCR to those obtained by culture and (ii) to evaluate a novel microtiter plate-based DNA hybridization assay (PCR-plate) by comparing it to agarose gel electrophoresis (PCR-gel) for detection of the PCR product. DNA for the PCR was extracted with a guanidine thiocyanate buffer and used in a PCR mixture containing primers directed against a reiterated gene sequence in B. pertussis (Q. He, J. Mertsola, H. Soini, M. Skurnik, O. Ruuskanen, and M. K. Viljanen, J. Clin, Microbiol. 31:642-645, 1993). Of 96 NPAs submitted from a targeted study group, 23 were positive by culture, 27 were positive by PCR-gel, and 31 were positive by PCR-plate. All culture-positive specimens were also positive by PCR. Of nine patients with culture-negative-PCR-positive results, six had discharge diagnoses of pertussis. Thus, PCR with plate-based product detection is a sensitive method for the laboratory detection of B. pertussis in NPAs. Additional advantages of the plate assay include rapidity, objectivity in reading results, specificity, and the capability of being adapted to a high-volume, automated system.

Outline for a disaster reduction programme for livestock in Central America

Central America has a high predisposition to natural disasters. For example, in the last 10 years nearly 40.000 people have died as a result of earthquakes, floods and hurricanes in Central America, at an estimated cost to these countries in excess of US$8.5 billon.Catastrophic events olso have a great impact on agriculture. In 1994, the direct losses in grain production in Central America as a result of droughts alone were estimated to be approximately US$44 million. The estimated value of the Central American livestock agriculture is US$3.3 billon, and employs nearly 10

of all people. Therefore, animal husbandry systems contibute significantly to the economic and political strength of Central American countries, and represent a large portion of each countrys standar of living, cultural heritage and identity. In many areas in Central America, the long term stability of the environment olso depends heavily on sustainable agriculture, which is based on traditional livestock husbandry systems and social structures. (AU)

The role of the veterinarian in hurricanes and other natural disasters

Hurricanes create a multiplicity of complicated problems and hazards ranging from outbreaks of infectious disease to animal control problems precipitated by destruction of property. A multidisciplinary response is required to solve such problems. The pool of knowledge derived from various professionals interacting with multiple levels of government agencies (federal, state, and local) will provide the expertise needed. Because the veterinarian is trined to deal with disease involving populations of animals (e.g. herds of flocks) as well as individuals, and because of his/her intensive clinical training, the veterinarian is uniquely qualified to deal with the disaster situation. The veterinarian possesses extensive knowledge in disease and disease processes and has the capability of disease and injury management in affected populations, which qualifies him/her for an essential role, with unlimited potential as a member of any disaster relief team. There is considerable potential for veterinarians to play a role in responding to natural disasters. The areas of disease control, animal care, animal control, protection of the food supply, disinfection/sterilization, and planning are all areas where veterinarians can take an active part. Inclusion of the veterinarian in the process of planning for and responding to natural disasters will yield significant public health benefits(AU)

Neutralization receptor-based immunoassay for detection of neutralizing antibodies to Escherichia coli verocytotoxin 1.

The NeutRELISA, a modification of the receptor enzyme-linked immunosorbent assay developed for the detection of verocytotoxin 1 (VT1) which permits the rapid detection of neutralizing antibodies (NAb) against this toxin, has been performed. A standard concentration of VT1 was preincubated with VT-immune or nonimmune rabbit serum. The serum-toxin mixtures were then added to microtiter plates coated with deacylated globotriosyl ceramide (lyso-Gb3). The reduction of VT1 binding to lyso-Gb3 in the immune serum-toxin mixtures compared with the VT1-Gb3 binding in the nonimmune serum-toxin mixtures was detected by using mouse monoclonal antibody to VT1. After standardization of the NeutRELISA with rabbit sera, 57 human control serum samples were tested to establish a cutoff value below which NeutRELISA results would be considered positive. Thirty-three single serum samples known to demonstrate NAb to VT1 by biological assay reproducibly demonstrated VT1 NAb when tested by the NeutRELISA. There was a close correlation between the biological VT1 neutralization assay and the NeutRELISA. This assay offers a practical, rapid, and reliable approach for the detection of NAb to VT1 and other verocytotoxins.

Criteria to verify attainment of maximal exercise tolerance test with obese females.

This study compared criteria used to determine attainment of maximal ETT used with normal subjects to results shown by obese subjects. Results indicated that obese subjects do not show the values that normal subjects show for plateau in oxygen consumption, respiratory exchange ratio, predicted maximal heart rate, or perceived exertion. Generally, less than 60% of the obese subjects met criteria for maximal ETT. These findings suggest that alternate criteria and/or alternate testing are needed to ascertain that ETT was maximal. Suggestions include longer treadmill stage times and the use of blood lactate.

Supracondylar fracture of the femur after GUEPAR total knee arthroplasty. A new treatment method.

A 71-year-old woman incurred an unstable, comminuted supracondylar fracture of the femur above the tip of a GUEPAR prosthesis. The prosthesis was not loose. Immediate open reduction and internal fixation were performed using a segment cut from an intramedullary rod. This provided axial alignment and functioned as an internal stent with stable fixation of the fracture. Supplementary fixation with a plate and screws, cerclage wires, and an autogenous bone graft led to early mobilization, solid bony union, and an excellent functional result.

Preoperative embolization in the treatment of osseous metastases from renal cell carcinoma.

Metastatic lesions due to renal cell carcinoma are frequently hypervascular. This study reports the results of preoperative embolization of skeletal metastases from hypernephroma. Reported for the first time in the English literature is the use of this technique for preoperative devascularization of metastatic lesions to the spine in eight patients. Effective devascularization was achieved in all peripheral lesions. Blood loss for peripheral lesions averaged 940 cc and compared favorably to 20 nonembolized cases, in whom average blood loss was 1975 cc. Spinal embolization requires careful identification and preservation of any segmental arteries that supply the anterior spinal artery. Effective spinal devascularization was achieved in six of eight patients. In two patients significant bleeding occurred as a result of incomplete embolization. This series supports the growing evidence for the efficacy and safety of selective arterial embolization in the preoperative control of hemostasis in patients with metastatic hypernephroma. Embolization of spinal metastases, although technically demanding, has been effective in devascularizing these lesions without serious neurologic complications.

Reflex sympathetic dystrophy of the knee.

Reflex sympathetic dystrophy of the knee has been studied in a series of 19 patients. Those diagnosed and treated early (at less than six months) did much better than those diagnosed and treated late. Nevertheless, when these patients were followed up at an average of 3.4 years from onset, not one was completely normal to objective tests with the Cybex II dynameter, an indication of the adverse prognosis with current methods of treatment.

Effects of cycloheximide and puromycin on cytotoxic activity of Escherichia coli verocytotoxin (Shiga-like toxin).

Verocytotoxin (VT)-producing Escherichia coli is closely associated with hemorrhagic colitis and hemolytic uremic syndrome. The diagnosis of this infection requires the demonstration of VT activity in fecal filtrates or the isolation of VT-producing E. coli from stools. To improve the sensitivity of the Vero cell assay for detecting VT, we investigated the interaction between this toxin and cycloheximide and puromycin, agents which, like VT and the related Shiga toxin, are protein synthesis inhibitors. Cycloheximide-treated cells were found to be about eightfold more sensitive to VT, this effect being most pronounced when the drug was added before the toxin. In contrast, puromycin treatment had an antagonistic effect in that it decreased the sensitivity of the cells to VT. In assays of VT in fecal filtrates, the addition of cycloheximide (at 4 to 8 micrograms/ml) increased the sensitivity without affecting the specificity of the assays. Likewise, the use of cycloheximide led to an increase in the sensitivity of the serum VT-neutralizing antibody test by a factor of over eightfold.

Abortion and perinatal sepsis associated with campylobacter infection.

Fetal loss or neonatal sepsis associated with campylobacter infection during pregnancy is infrequently recognized. As reported herein, one case of premature labor and neonatal sepsis due to Campylobacter fetus subspecies fetus was treated successfully with ampicillin and gentamicin. Only 19 similar cases have been cited in the literature. A review of these 19 cases reveals that the Campylobacter species involved were probably C. fetus subspecies fetus in nine instances, Campylobacter jejuni in nine, and Campylobacter coli in one. There were no significant species-related differences in clinical presentation or outcome. Eighteen of 20 pregnancies (including tht described herein) ended prematurely at 13-32 weeks of gestation. All of the mothers survived, but fetal/neonatal mortality was 80%. The pathogenesis of campylobacter infection in this situation probably involves maternal bacteremia originating from the bowel, with subsequent feto-placental involvement. Early recognition and treatment may improve fetal/neonatal outcome.

Modified ammonia electrode method to investigate D-asparagine breakdown by Campylobacter strains.

An ammonia electrode method has been developed for investigating the deamination of amino acids by bacteria. It consists of incubating a standard inoculum of organisms in an amino acid solution and then measuring the amount of ammonia evolved by the electrode. Two hundred and twelve Campylobacter strains (118 C. jejuni and 94 C. coli) were tested for their ability to break down D-asparagine by this method. Organism control (bacterial suspension in buffer alone) values ranged from 0.44 to 2.0 (mean 0.93 +/- 0.24) ammonia concentration (AC) units (one AC unit is equal to 10(-5) mol of ammonia per liter), whereas test values ranged from 0.60 to 46.0 units. Test ACs of less than 2 units (97 strains) were considered negative, whereas ACs of greater than or equal to 10 (77 strains) were considered positive for D-asparaginase; 38 (18%) strains with ACs between 2 and 10 units were provisionally assigned an intermediate status. The amount of ammonia produced by strains with ACs of greater than or equal to 10 increased greatly when the inoculum size was increased, whereas this was not a feature of strains with ACs of less than 2 units. The presence or absence of an inoculum effect was instrumental in classifying strains with intermediate ACs and allowed a breakpoint to be defined. When the ammonia electrode method was repeated, 97.6% of the 212 strains gave the same positive or negative reaction that they did on the first occasion. Thus the test was highly reproducible. Five strains (all porcine C. coli from Germany) were unclassifiable because they repeatedly gave either a weak-positive or negative reaction. Overall, 12.7% of C. jejuni strains and 86.2% of C. coli strains were positive for D-asparaginase. The ammonia electrode method was found to be simple and reliable for separating strains on the basis of D-asparaginase activity.

Evaluation of a blood-free, charcoal-based, selective medium for the isolation of Campylobacter organisms from feces.

A blood-free, charcoal-based selective medium (CSM) consisting of a Columbia agar base, activated charcoal (4 g/liter), hematin (0.032 g/liter), sodium pyruvate (0.1 g/liter), cefoperazone (32 mg/liter), vancomycin (20 mg/liter), and cycloheximide (100 mg/liter) supported the growth of Campylobacter jejuni and C. coli with colony counts equivalent to those obtained on antibiotic-free horse blood agar. CSM was compared to Skirrow medium (SKM) for the recovery of C. jejuni and C. coli from stools of patients with diarrhea, the media being incubated for 2 days under reduced oxygen tension at 43 degrees C. These campylobacters were isolated from 35 (2.9%) of 1,227 stools tested (29 on both media, 5 on CSM alone, and one on SKM alone). Whenever C. jejuni and C. coli were recovered, growth was pure on 29 CSM cultures (85%), but on only 11 SKM cultures (37%). Complete suppression of "contaminating" flora occurred in 704 CSM cultures (57%) compared with 426 SKM cultures (35%). CSM more effectively suppressed contaminating pseudomonads, gram-positive organisms, and yeasts than did SKM; both media failed to suppress members of the family Enterobacteriaceae in about a quarter of the samples. Studies on 20 representative Enterobacteriaceae contaminants showed that susceptibility to cefoperazone and growth on CSM were markedly dependent on inoculum size; 12 strains were inhibited by cefoperazone (32 mg/liter) at inoculum sizes of 5 X 10(2) and 5 X 10(4) but not 5 X 10(6) organisms, indicating that the frequency of contaminants on CSM could probably be reduced further by ensuring that stools were not inoculated too heavily on CSM. Our findings confirm that charcoal is an effective substitute for blood in media for growing campylobacters, and that CSM is a highly effective blood-free selective medium for isolating C. jejuni and C. coli from stools.