Effect of post length and diameter on remaining dentine thickness in maxillary central and lateral incisors.

AIM: To investigate the effect of root canal and post-space preparation on the remaining dentine thickness in the apical region of maxillary central and lateral incisors. METHODOLOGY: Fifty extracted maxillary incisors (25 centrals and 25 laterals) were mounted and then sectioned at two levels: 5 and 7 mm from the apex. Computerized images were obtained and a digital image analysis system was used to measure dentine thickness for each section at eight sites: labial, mesial, distal, palatal, mesio-labial, disto-labial, mesio-palatal and disto-palatal. Measurements were repeated at baseline and after both root canal and post-space preparation. Central and lateral incisors were divided into five groups each (n = 5) according to the drill used for post-space preparation: Groups 1 through 4 were prepared using Parapost drills sizes 4.5, 5, 5.5 and 6 respectively. For group 5, size 4 Gates Glidden was used. RESULTS: For both teeth, and at the two levels there was a significant difference (P < 0.001) between the baseline dentine thickness and that remaining after post-space preparation at all sites. There was a statistically significant difference (P = 0.007) between the remaining dentine thickness at 5 and 7 mm at all sites. The average amount of dentine removed ranged from 0.20 to 0.52 mm. In all groups, and for both teeth, some specimens had <1 mm of remaining dentine thickness. CONCLUSIONS: Posts should be used carefully when restoring root filled maxillary incisors.

Her-2 neu (Cerb-B2) expression in fine needle aspiration samples of breast carcinoma: A pilot study comparing FISH, CISH and immunocytochemistry.

BACKGROUND: Breast cancers with Her-2 neu gene amplification are recognized as important markers for aggressive disease and targets which respond to therapy with trastuzumab. Her-2 neu testing on histological sections is routinely performed to select patients who may benefit from anti- Her-2 neu therapy. Few reports are available which document Her-2 neu status on fine needle aspirates (FNA). AIM: This pilot study is to document expression of Her-2 neu (Cerb-B2) on cytospin smears from FNA of patients with breast carcinoma. MATERIALS AND METHODS: Twenty samples of FNA already collected for diagnostic purposes from patients with primary breast carcinoma were studied for demonstration of Her-2 neu expression by immunohistochemistry (IHC), Fluorescent in-situ hybridization (FISH) and chromogenic in-situ hybridization (CISH) on cytospin smears from FNA. Their expression was compared with tissue sections where possible. RESULTS: Good correlation was observed between Her-2 neu protein expression and gene amplification in cytospin smears. Three of five (60%) breast carcinomas cases with 2+ and 3+ staining on IHC showed gene amplification by FISH and CISH. Three of 7 (43%) and 5 of 7 (71%) cases negative/1+ staining on IHC did not show gene amplification by FISH and CISH respectively. Tissue sections from 10 cases with 2+ and 3+ staining for Her2neu by IHC showed gene amplification in 8 cases. CONCLUSION: Demonstration of Her-2 neu by IHC, FISH or CISH in FNA is possible and may play a role in the management of patients with advanced breast cancer or those cases where surgical resection is not advisable.

The role of anticipation and fear of pain in the persistence of avoidance behavior in patients with chronic low back pain.

STUDY DESIGN: A correlative design using stepwise regression analysis. OBJECTIVE: To explore the variation in spinal isometric strength that can be accounted for by anticipation of pain, sensory perception of pain, functional disability belief, and the fear-avoidance belief in chronic low back pain patients. SUMMARY OF THE BACKGROUND DATA: Several biobehavioral factors contribute to the persistence of pain behavior in chronic patients. Recent studies suggest a need to explore the relation between reduced physical performance and the sensory and cognitive perception of pain. METHODS: Sixty-three patients with chronic low back pain 20 to 56 years of age participated in this study. Visual Analogs Scales, the Fear-Avoidance Belief questionnaire, and the Disability Belief questionnaire were used to measure the sensory and cognitive dimensions of pain. Spinal isometric strength was measured by the Medx lumbar extension machine. RESULTS: Analysis of variance and the stepwise regression analysis demonstrated that anticipation of pain and the fear-avoidance belief about physical activity significantly predicted variation in the spinal isometric strength deficit P < 0. 001. True pain experienced during the testing and answers to the Disability Belief questionnaire were not related. CONCLUSION: The results of this study strongly support the hypothesis that spinal physical capacity in chronicity is not explained solely by the sensory perception of pain. The anticipation of pain and the fear-avoidance belief about physical activities were the strongest predictors of the variation in physical performance.

Assessment of the levels of chlorinated pesticides in breast milk in Kuwait.

Breast milk samples, randomly collected from 32 Kuwaiti donors were analysed for chlorinated pesticides. DDE residues ranged from 127 to 3333 micrograms/kg, averaging, 833 micrograms/kg, expressed on a fat weight basis. DDT levels ranged from 0.6 to 67 micrograms/kg fat and averaged 12.4 micrograms/kg, fat. High DDE/DDT ratios were found, which indicated that the exposure to DDT, in most cases, happened quite some time ago. In addition many of the samples also contained isomers of HCH, heptachlor-epoxide, aldrin, dieldrin and endrin. Residue levels of non-DDT pesticides were generally low. Overall levels of DDT-pesticides in Kuwaiti milk samples were lower than levels reported from other Middle Eastern countries, although methodologies may not be directly comparable.

BstB7SI (R decreases CCGGY), a thermostable isoschizomer of Cfr10I, from a strain of Bacillus stearothermophilus isolated from oil-contaminated soil in Kuwait.

Isolates of thermophilic bacteria from desert soil in Kuwait, heavily contaminated with crude oil, have been screened for the presence of restriction endonuclease activity. One of the isolates (B7S), identified as Bacillus stearothermophilus, showed a high level of restriction endonuclease activity when a cell-free extract was incubated with lambda bacteriophage DNA at 65 degrees C. A type II restriction endonuclease (BstB7SI) has been partially purified from this isolate. BstB7SI recognises the six-base sequence RCCGGY (R = A or G; Y = T or C) and hydrolyses the phosphodiester bond in both strands of the DNA substrate between the first and second bases of the recognition sequence 5'-R decreases CCGGY-3'producing four-base 5' overhangs. BstB7SI is therefore an isoschizomer of the mesophilic prototype restriction endonuclease Cfr10I. BstB7SI has a pH optimum of 9.7, requires 10 mM MgCl2 and 75 mM NaCl for maximum activity, and retains full enzyme activity when incubated for 5 min at temperatures up to 70 degrees C.