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Biomedical subjects

F Barnett

Publications and source records attributed to F Barnett.

At least 19 recordsLinked to original sources
PubMed2005

The use of lumbar spinal stabilization techniques during the performance of abdominal strengthening exercise variations.

AIM: The lumbar spinal stabilization techniques in abdominal hollowing and bracing are known to facilitate the level of activity in the muscles transversus abdominis and obliquus internus (TA/OI). The relative timing of activation and the effect of combination with other tasks are currently unknown. The objective of this study was to determine whether the performance of abdominal hollowing and bracing could promote the voluntary preferential recruitment of TA/OI muscles when performed prior to abdominal strengthening exercise variations. METHODS: The trunk muscles TA/OI, rectus abdominis and obliquus externus were investigated using surface EMG. A pressure transducer under the lumbar spine detected spinal movement. Eighteen male subjects performed a series of 4 abdominal strengthening exercise variations. Pressure cuff and electromyographic onset times were collected and analyzed. RESULTS: TA/OI muscle site was recruited significantly earlier than the upper rectus abdominis site for the hollow with curl exercise. The TA/OI site was also ranked as first activated site in the majority of subjects during exercises where stabilization techniques of hollowing and bracing were used. CONCLUSIONS: Abdominal hollowing was an effective method for selective preferential voluntary recruitment of TA/OI site prior to the performance of the curl type abdominal strengthening exercise variation. The other variations brace with curl and hold and hollow with rotation also tend to recruit TA/OI site first, however the timing was not significantly different.

Abdominal Muscles↗
PubMed2001

Comparison of laterally condensed .06 and .02 tapered Gutta-Percha and sealer in vitro.

The purpose of this in vitro study was to compare the quality of the seal in canals prepared in a standardized manner and obturated with a .06 or a .02 tapered gutta-percha master cone using lateral condensation. Forty-four extracted human anterior teeth with single, straight canals were divided into two experimental groups of 20 teeth each and two control groups of 2 teeth each. The teeth were instrumented with Series 29 Profile .06 tapered rotary nickel-titanium files to a master apical file of 0.46 mm. Teeth in group 1 were obturated with a .02 tapered master gutta-percha cone and Roth 801 sealer using lateral condensation. Teeth in group 2 were obturated similarly, except a .06 tapered master gutta-percha cone was used. The depth of spreader penetration was recorded in millimeters. Positive control teeth were instrumented but not filled. Negative control teeth were instrumented, obturated, and externally sealed. The teeth were placed into a coronal leakage apparatus that contained an upper and lower reservoir of trypticase soy broth separated by the tooth. A 24-h growth of Proteus vulgaris in 0.25 ml of trypticase soy broth was placed in the coronal reservoir every 7 days for 70 days and incubated at 37 degrees C. Student's t test was used to determine whether there was a difference in spreader penetration between the groups, and a Fisher's exact test was used to determine whether there was a difference in bacterial leakage. The positive and negative controls validated the testing model. When a .02 tapered master cone was used, the spreader penetrated significantly closer to working length than when a .06 tapered master cone was used (p < 0.05). The difference between the groups in the number of samples that demonstrated complete bacterial penetration was not significant (p > 0.05).

Chi-Square Distribution↗
PubMed1995

A turnover study in the male rat of plasma-bound 59Fe, 114Inm and 109Cd with particular reference to the gonad.

After intravenous doses of the plasma-bound radionuclides 59Fe, 114Inm and 109Cd, only a minute percentage localizes in the rat testis and remains largely unchanged with time. Intratesticular injection of appropriately reduced volumes led to much higher proportionate percentage retention of 14, 65 and 11 for 59Fe, 114Inm and 109Cd, respectively. By this route, significant feedback of the elements escaping initial binding was prevented. Distinct but different testicular turnovers were now discernible. As a receptor of fluid and spermatozoa from the testicular tubules, the epididymis provides an indication of entry into and interaction of the metals with spermatogenic cells. For 59Fe no measurable changes were detected, whereas a progressive increase in epididymal 114Inm occurred, which had not reached a plateau by 70 days. 109Cd, now demonstrated within the testicular tubules by autoradiography, remained at constant organ level for upwards of 16 days but had declined by 25% by 57 days. At this point, the epididymis showed a five-fold increase in the radionuclide, declining to one-half this value by 126 days. Since 109Cd is carrier free, the data reflect a body turnover of dietary cadmium. These results, overall, are compatible with the entry of a proportion of each radionuclide into the seminiferous tubules and reaction with spermatogenic cells. Possible interpretations of the observed differences are presented.

Animals↗
PubMed1992

Pulpal response to restorative procedures and materials.

This paper reviews the pulpal response to common restorative procedures and dental materials. Pulpal inflammation and dentin hypersensitivity are commonly associated with routine restorative procedures. Although it is not possible to avoid injury to the pulp completely, in order to prevent unnecessary adverse effects, the practicing dentist should be aware of the potential dangers involved. This article provides a current review of recent findings of the pulpal response to glass ionomer cements and acid-etch composite resin materials.

Composite Resins↗
PubMed1990

The complications of trabeculectomy (a 20-year follow-up).

The complications of trabeculectomy were studied in two groups of patients taken from a stable white population. The first group who had had their operation when it was first introduced 22 years ago, had been previously treated with prolonged medication, the second group had been operated upon recently and had had short-term pre-operative medication. This study confirmed that trabeculectomy predictably reduces the intraocular pressure to within the accepted normal range and that the pressure level below which the intraocular pressure could not be expected to fall was congruent to 14 mm/Hg. It also revealed that although some post operative abnormality was noted in two-thirds of the patients there were no long term problems which could be related to any operative or immediately post-operative complications, including shallow anterior chambers, uveitis and hyphaema. However, there was a long term reduction in the visual acuity and visual fields of about one-third of the patients, which was not related to cataract formation, macular problems, the height of the preoperative intraocular pressure, the amount by which this fell as a result of the surgery, or the amount, length or type of preoperative medication given before the operation. Although there was some increase in cataracts throughout the whole long term group this was mainly in those who had cataract prior to surgery; the increase was not related to operations or any other factor other than corneo-lenticular contact post-operatively.

Aged↗
PubMed1990

Periapical bacterial plaque in teeth refractory to endodontic treatment.

It has recently been found that bacteria are able to survive and maintain an infectious disease process in periapical lesions of nonvital teeth. The purpose of this study was to examine the surfaces of root tips removed during surgical-endodontic treatment for the presence of microorganisms. A full thickness flap was reflected under strict surgical asepsis and the periapical lesions were enucleated and removed. About 2-3 mm of the root was cut off, rinsed in sterile saline and placed in 10% neutral-buffered formalin. Upon fixation, the root tips were dehydrated, air-dried and given an electrically conducting coat of gold in a vacuum evaporator. The root tips were then studied in a Jeol, JSM-U3 scanning electron microscope, usually operated at 20 kV. The root surfaces were covered with soft tissue, except at the apex of the roots, where a continuous, smooth and structureless coating was seen, apparently adjacent to the apical foramen. At higher magnification a variety of bacterial forms were recognized in the smooth coating. A bacterial plaque was observed in irregularities of the surfaces between fiber bundles and cells and in crypts and holes. The bacteria were held together by an extracellular material and the plaque was dominated by cocci and rods. Fibrillar forms were recognized as well, often with cocci attached to their surfaces.

Bacteria↗
PubMed1990

Demonstration of Bacteroides intermedius in periapical tissue using indirect immunofluorescence microscopy.

The presence of bacteria in periapical lesions of teeth with necrotic pulp has been demonstrated by microbiological sampling of periapical lesions during endodontic surgery. The purpose of this study was to confirm the presence of Bacteroides intermedius in a periapical granuloma using an indirect immunofluorescence technique. Histologic sections of a periapical granuloma were incubated with a rabbit antiserum to B. intermedius. After incubation with secondary antibody (fluorescein-conjugated goat anti-rabbit IgG), an intense fluorescent staining was observed in areas of the tissue sections. Control tissue sections that were incubated without the antibody remained unstained. The results obtained with the indirect immunofluorescence technique supported our cultural findings that microorganisms, e.g. B. intermedius, were present in the tissue of the periapical granuloma.

Adult↗
PubMed1989

In vivo sealing ability of calcium hydroxide-containing root canal sealers.

It was the purpose of this study to determine the sealing ability of 2 commercially available calcium hydroxide-containing root canal sealers, CRCS and Sealapex. One hundred sixty single-rooted human teeth were used. The clinical crowns were removed and the roots were cleaned mechanically and by immersion for 24 h in 5% sodium hypochlorite. The root canals were then instrumented to size 80 at the apical foramen and the roots were sterilized by gamma-radiation. Under aseptic conditions the root canals were filled with a gutta-percha master cone size 70 and Sealapex (48 roots), CRCS (48 roots), and a zinc oxide-eugenol type sealer, Roth 801 (50 roots). The coronal aspects of the root canals were then sealed with zinc oxide-eugenol cement. In order to bring the roots and root filling materials in contact with tissue and tissue fluids, the roots were implanted subcutaneously in rabbits for 90 days and 1 year. Leakage as demonstrated by penetration of India ink was evaluated using a stereomicroscope. The best results were obtained with CRCS. Significantly less leakage occurred with both calcium hydroxide-containing sealers than with the traditional zinc oxide-eugenol sealer.

Calcium Hydroxide↗
PubMed1989

Differentiation of radicular cyst and granulomas using computerized tomography.

The purpose of this investigation was to study periapical lesions by means of computerized tomography to ascertain if this noninvasive method could be of value in distinguishing between radicular cysts and granulomas. Periapical radiographs were taken of the teeth of 60 human cadavers. Periapical radiolucencies were seen in conjunction with 33 teeth. Based on the periapical radiographs, an oral radiologist (J.P.) attempted to select 4 granulomas and 4 cysts from the 33 radiolucencies. Computerized tomography was performed on the root tips and the periapical lesions of these 8 teeth. The roots and periapical lesions were then surgically removed and prepared histologically for microscopic examination. In the tomographs, 7 of the periapical lesions had a cloudy appearance with a density similar to each other and to the surrounding soft tissue. In the eighth lesion a homogeneous dark area with a distinctly lower density could be distinguished from surrounding cloudy areas. Histologically, the dark area was shown to be an epithelialized cyst cavity. The other 7 lesions were granulomas. Thus, a cyst could be differentiated from periapical granulomas by computerized tomography because of a marked difference in density between the content of the cyst cavity and granulomatous tissue.

Diagnosis, Differential↗