The reliability and accuracy of intraoperative imprint cytology of sentinel lymph nodes in breast cancer.

OBJECTIVE: Sentinel lymph node (SLN) biopsy is a new component of the surgical treatment of breast cancer that accurately predicts axillary status. In this study the authors evaluated the accuracy of intraoperative imprint cytology (IC) in comparison with definitive histologic evaluation of SLN in breast cancer patients. METHODS: A total 413 women with breast carcinoma and clinically negative axillary nodes underwent breast surgery and SLN biopsy. Mapping of SLN involved injection of (99m)Technecium labelled human albumin nanocolloid particles and Patent Blue dye. At the Department of Pathology, SLNs were bisected along its major axis. Both halves were imprinted 2-4 times on the slides and immediate staining with Hemacolor (Merck Germany) was performed for intraoperative examination. Imprint node negative women underwent no further surgery, while node positive women proceeded to full axillary clearance. Histological analysis of the SLN involved serial sectioning of the whole node with H&E and immunostaining for cytokeratin. RESULTS: Definitive histology revealed metastases (pN+) in 159/413 patients (38.5%): 69 (16.7%) macro metastases, 57 (13.8%) micro metastases, and 33 (8%) women with only isolated IHC positive cells or positive cell groups smaller than 0.2 mm (pNO sn+). The other 254 women had negative SLN biopsy. Imprint cytology detected 54/69 macro metastases, and 4/57 micro metastases. In the group with negative SLN (254), 2 cases were ''false positives''. CONCLUSIONS: Imprint of SLN biopsy can identify a negative axilla with high accuracy (specificity 99.2%). Overall sensitivity is only 36.5%, but macrometastases are detected in 77% which is important for performing ALDN in one session with operation of primary tumour.

Role of imprint cytology in the intraoperative evaluation of sentinel lymph nodes for malignant melanoma.

Controversy exists over the utility of different methods for intra-operative sentinel lymph node (SLN) evaluation in patients with malignant melanoma (MM). The aim of this study was to evaluate the role of intra-operative imprint cytology (IC) in patients with MM. 215 SLNs from 99 patients with MM were examined by IC and results compared with the results of permanent sections. 24 patients had MM deposits in their SLNs and this was confirmed by histological examination. Intraoperative IC was positive in 11 of these patients (46% sensitivity). In addition, there were three false-positive IC diagnoses (79% positive predictive value); one of these was due to contamination during the sectioning of the SLN. The specificity and the negative predictive values of the IC were 96 and 85%, respectively. IC is a valuable method of intra-operative SLN evaluation which can spare approximately half of the patients with clinically occult regional metastases from a second surgical procedure. However, special care must be taken to avoid false-positive results due to contamination.

Added value of blue dye in sentinel node biopsy for breast cancer.

Sentinel node biopsy in breast cancer is a new rapidly advancing minimal invasive procedure which enables nodal staging of clinically node negative breast cancer patients without performing complete axillary dissection. There are still controversies over the added value of Blue Dye when lymphoscintigraphy and gamma probe are used. In our series, 91 consecutive patients with invasive breast carcinoma were operated by a single surgeon, using lymphoscintigraphy, gamma probe and Blue Dye. The sentinel nodes (SLN) were histologically examined by HE and immunohistochemistry. Lymphoscintigraphy was succesful in 81 patients (89%). After the injection of Blue Dye, SLN could be identified in all 91 patients. Metastases in the SLN were present in 35 patients. We retrieved 128 SLN, of these 93 were hot and blue, 19 only hot and 16 only blue. The distribution of metastatic and nonmetastatic SLN between these three labeling groups was not different (P = 0.9361). We could not show any difference in the metastatic involvement of SLN in patients in whom preoperative lymphoscintigraphy could visualise the SLN preoperatively compared to those in whom it could not (P = 0.7315). False negativity calculated in our initial series of 36 patients was 0%. Our study showed added value of Blue Dye in detection of metastatic and nonmetastatic SLN.

Reactivity of anomeric 1alpha- and 1beta-pentofuranosyl azide derivatives in ammonia chemical ionization.

Electron impact (EI), fast atom bombardment (FAB) and ammonia chemical ionization [CI(NH3)] mass spectrometry were applied with the aim of differentiating between the anomeric 1alpha- and 1beta-azidopentofuranosyl derivatives. Calculated ammonium affinities [AA(M)] and proton affinities [PA(M)] show that beta-anomers have higher affinities for H+ and NH4+ ions than alpha-azides. Protonated molecules, obtained by CI(NH3) of azidofuranosyl derivatives, lose HN3 giving abundant furanosyl (S+) ions. Ammonia solvation of MH+ ions competes with the previous reaction producing the [SNHN2NH3]+ ion, a competitive product to the ammonium-attached [SN3NH4]+ ion. The fragmentation pathways of the stable and metastable [MNH4]+, MH+ ions, and several other important fragment ions, were determined using mass analyzed ion kinetic energy spectrometry (MIKES). The abundance of the [SN3NH4]+ and/or [SNHN2NH3]+ ions was found to correlate inversely with the exothermicity of ammonia solvation of the MH+ ion. The abundance of the fragment ions [SNHNH3]+, [SNH3]+ and SNH+ in some examples correlates with the exothermicity of the corresponding [MNH4]+ and MH+ parent ion formation. The fragment ions SNH3+ and SNHNH3+ can be formed, at least in part, in the ammonia solvation reaction of the S+ and SNH+ ions taking place within the high-pressure region of the CI ion source.

An evaluation of the quality of orthodontic attachment offered by single- and double-mesh bracket bases using the finite element method of stress analysis.

The objective of this study was to evaluate the influence of bracket base mesh geometry on the stresses generated in the bracket-cement-tooth continuum by a shear/peel load case. A validated three-dimensional finite element model of the bracket-cement-tooth system was constructed consisting of 15,324 nodes and 2971 finite elements. Cement geometric and physical properties were held constant and bracket base geometry was varied, representing a variety of single-mesh configurations and 1 double-mesh design. For the single-mesh designs, increasing wire diameter (100-400 microm) resulted in a decrease in enamel and cement stresses. Increases in wire mesh spacing (200-750 microm) increased the major principal stress recorded in the enamel and adhesive at all wire diameters. Within the bracket, the major principal stress increased significantly at wire spacing above 400-500 microm. However, within the impregnated wire mesh (IWM), the major principal stress decreased as wire space increased. When the double-mesh bracket base was considered, the combined mesh layers resulted in a decrease in the stresses recorded in the most superficial (coarse) mesh layer and an increase in the stresses recorded in the deepest (fine mesh) layer when compared with the single-layer designs in isolation. Modification of single-mesh spacing and wire diameter influences the magnitude and distribution of stresses within the bracket-cement-tooth continuum. The use of a double-mesh design results in a reduction in the stresses recorded in the most superficial mesh. Mesh design influenced stress distribution in this study, primarily by determining the flexibility of the bracket base.

An evaluation of the influence of orthodontic adhesive on the stresses generated in a bonded bracket finite element model.

The objective of this study was to evaluate the stresses generated in the bracket-cement-tooth continuum by a tensile load case when the physical and geometric properties of cement are varied. A 2-stage approach was used. In the first stage, a validated 3-dimensional finite element model of the bracket-cement-tooth system was constructed that consisted of 15,324 nodes and 2971 finite elements. Bracket base geometry was held constant; the physical properties (elastic modulus; Poisson's ratio) and geometry (lute thickness) of the cement varied. A simplified 2-dimensional model was then developed to investigate the localized effects of the cement lute thickness and the shape of the lute periphery on the stress distribution in the system. Small increases in stress were recorded under load within the cement as the rigidity of the cement increased. Similarly, Poisson's ratio values above 0.4 appeared to have a small influence on the major principal stresses in the impregnated wire mesh layer when a tensile force was applied. Variation in lute thickness was shown to have an influence on the distribution of major principal stresses within the cement lute. Increased stresses were recorded at the lute periphery as the lute dimensions increased. The morphologic features of the lute periphery also appeared to have had a significant effect on the performance of an orthodontic adhesive. Acute cement-enamel angles resulted in an increased chance of singularity development and attachment failure. The physical properties and thickness of the cement lute and the shape of the cement lute periphery contribute to the stress distribution within the bracket-cement-tooth continuum and, therefore, the quality of orthodontic attachment provided.

Numerical investigation of fixed orthodontic brackets.

This paper presents the results of investigations into the mechanical behaviour of fixed orthodontic brackets. Special attention has been paid to the detailed modelling of the interface between the bracket base and an adhesive by which attachment is made to the tooth surface. Properties of this interface were taken as design parameters with the aim of investigating their influence on the stress field induced during bracket removal at the end of the treatment. Stress-strain analysis was performed using a finite element program developed in-house.

An evaluation of the stresses generated in a bonded orthodontic attachment by three different load cases using the Finite Element Method of stress analysis.

The objective of the investigation was to develop a clinically valid three-dimensional computer model of the orthodontic bracket-cement-tooth continuum, and determine the magnitude and distribution of stresses generated by three different load cases. A three-dimensional finite element model of the bracket-cement-tooth system was constructed consisting of 15,324 nodes and 2,971 finite elements. The stresses induced in the bracket-tooth interface by a masticatory load, a peel force and a twisting couple were recorded. The maximum principal stresses resulting from occlusal and 'twisting' forces are distributed toward the lute periphery. Peel forces, applied to the bracket tie wing, are concentrated beneath the bracket stem. Twisting forces result in the highest enamel stresses. The quality of orthodontic attachment can be explained by the magnitude and distribution of major principal stresses within the cement and impregnated bracket base. Shear and shear/peel forces are most likely to induce crack propagation within the adhesive layer. However, when a twisting action is used to remove orthodontic brackets, enamel failure is most likely. A clearer insight into the complexity of the bracket-cement-tooth system has been provided by numerical and finite element investigations. Further investigations, evaluating the influence of bracket base designs and orthodontic cement physical and geometric properties are indicated. Refereed Scientific Paper

Effect of intra-abdominal position of the bladder neck and stability of its supporting structures on pressure transmission ratio after colposuspension.

The aim of this prospective study was to evaluate the influence of the higher intra-abdominal position of the bladder neck and the stability of its supporting structures after colposuspension, on pressure transmission to the urethra at the level of the bladder neck. Twenty-eight patients were included in the study. The pressure transmission ratio (PTR) was calculated at the level of the bladder neck, whereas the position and mobility of the bladder neck during coughing were evaluated with perineal ultrasound examination. The measurements were performed before and 3 months after colposuspension. After colposuspension we found a significant elevation of the PTR (P=0.001), a significantly higher intra-abdominal position (P=0.001) and decreased mobility (P=0.001) of the bladder neck during coughing. Also, a negative correlation between the elevation of PTR and decreased mobility of the bladder neck during coughing (r = -0.5049; P = 0.006) and a weak correlation between the elevation of PTR and a higher intra-abdominal position of the bladder neck during coughing were found (r = 0.3828; P=0.044). Reinforced tension resistance of the bladder neck supporting structures seems to be more important than intra-abdominal position of the bladder neck in achieving effective pressure transmission after colposuspension.

Conservative treatment of female stress urinary incontinence with functional electrical stimulation.

BACKGROUND: Treatment of stress urinary incontinence with functional electrical stimulation (FES) is a recent and efficient method of conservative treatment. STUDY DESIGN: Before treatment, examinations determining the type of urinary incontinence should be made: patient history, pelvic and urologic examination, laboratory tests of urine, multi-channel urodynamic tests. The degree of urinary incontinence is assessed by pad tests. Only the patients with moderate stress urinary incontinence without or with a mild utero-vaginal prolapse, are treated by FES. The parameters of stimulation: the impulse is rectangular and biphasic, duration of impulse is 1 ms, frequency of impulse is 20 Hz, and intensity of current 35 mA. The chronic treatment with FES should be applied 1.5-2 h daily for 3 months. This long-term treatment requires appropriate motivation of the patient. RESULTS: Three months after terminated treatment 56 of the total 111 patients (50.5%) were cured, in 26 (23.4%) the condition improved, whereas in 29 patients (26.1%) the treatment failed. CONCLUSIONS: The efficiency of treatment depends on the patient selection, parameters of electrical stimulation, stimulator of the pelvic floor muscles, mode of stimulation--chronic stimulation, and on motivation of the patient.

Lapstatin, a new aminopeptidase inhibitor produced by Streptomyces rimosus, inhibits autogenous aminopeptidases.

Lapstatin, a low-molecular-weight aminopeptidase inhibitor, was purified to homogeneity from Streptomyces rimosus culture filtrates. The purification procedure included extraction with methanol, followed by chromatography on Dowex 50WX4, AG50WX4, and HPLC RP C18 columns. By amino acid analysis, mass spectrometry, and NMR spectroscopy, the structure of lapstatin was shown to be 3-amino-2-hydroxy-4-methylpentanoylvaline. Lapstatin inhibited the extracellular leucine aminopeptidases from Streptomyces rimosus, Streptomyces griseus, and Aeromonas proteolytica with an IC50 in the range of 0.3-2.4 microM. IC50 values for other enzymes tested were at least tenfold higher. Leucine aminopeptidase from Streptomyces griseus was inhibited in a competitive manner, with an inhibition constant of 5 x 10(-7) M. Lapstatin is the first low-molecular-weight compound isolated from streptomycetes shown to inhibit an autogenous aminopeptidase.

The influence of obesity, constitution and physical work on the phenomenon of urinary incontinence in women.

Urinary incontinence in women is a common and complex problem which can be defined and classified as stress, urge and mixed incontinence. Three of the eight most common risk factors are obesity, constitution and physical work, in addition to age, length of menstrual cycle, number of pregnancies, education and level of health awareness. Women with the diagnosis of urinary incontinence were invited to respond to questionnaires on a voluntary basis. The three factors found to be associated with urinary incontinence are increased body weight, strong osteomuscular structure and hard physical work. These indicate that the work of a health team must take a holistic approach to women even before the phenomenon of urinary incontinence occurs.

Stoichiometry and heterogeneity of the pro-region chain in tetrameric human cathepsin C.

The subunit structure and composition of mature human cathepsin C, an oligomeric cysteine proteinase, has been characterised in detail. The heavy chain, light chain and pro-region peptides are shown to be held together solely by non-covalent interactions, and to be present in equimolar ratio, suggesting an important structural role for the residual pro-region chain which is strongly bound to the enzyme. The mass of the light chain, as determined by mass spectrometry, combined with its N-terminal sequence, determines the position of cleavage from the heavy chain. Amino-acid sequencing has led to definition of the 13.5 kDa N-terminal part of the pro-region which remains in the mature enzyme, the C-terminal moiety of 10 kDa being cleaved out and lost from the pro-peptide on activation. The residual pro-region is heterogeneous, a proportion being intact and the remainder being cleaved at alternative positions 58 or 61, yielding two smaller peptides joined by disulphide bond. The proportion of cleaved form was found to vary with tissue and enzyme preparation but did not affect enzyme activity. The molecular masses of the constituent chains after deglycosylation lead to a protein mass of 158 kDa. All four potential glycosylation sites are glycosylated.

Survey of Canadian doctors' attitudes to cancer staging.

OBJECTIVE: To collect opinions on the value of cancer staging, the impediments to realizing comprehensive staging and the support that may exist for providing stage information to cancer registries. DESIGN: The National Cancer Institute of Canada and the Canadian Committee on Cancer Staging have conducted an opinion survey. Opinions were sought about who should be responsible for allocating the stage, what criteria should be used to alter staging classification and whether population-based registries should contain comprehensive staging data. SETTING: The survey involved 1748 practising cancer specialists representing a cross section of Canadian physicians involved in the treatment and assessment of cancer patients. RESULTS: The overall response rate was 44.4%. Respondents gave broad support to the universal recording of cancer stage in Canada with 75.2% to 78.6% stating that staging is extremely useful for research, cancer statistics and caring for patients. Most respondents (98%) considered that all new cancer patients should have a specific stage assigned at the time of their first definitive treatment, and 78% believed that the clinician responsible for treating patients should determine the stage of cancer. A high proportion (73% to 81%) of respondents considered staging to be extremely important to define disease extent, make treatment decisions, estimate prognosis, facilitate consistent management and to compare results of treatment. The respondents consider lack of adequate information from pathology and imaging reports as barriers to staging. Only a small proportion of respondents were familiar with the organizations responsible for promoting and developing staging classifications. CONCLUSIONS: The Canadian survey showed strong support for universal staging and for the development of a central coordinated effort to promote cancer staging in Canada.

Bovine stefin C, a new member of the stefin family.

Four low M(r) cysteine proteinase inhibitors with different pI values were isolated from bovine thymus using alkaline activation of the gland homogenate, affinity chromatography on carboxymethyl-papain-Sepharose, gel filtration on Sephadex G-50, ion-exchange chromatography on a DEAE-cellulose column and a fast protein liquid chromatography Mono Q column, and hydrophobic chromatography on a TSK Phenyl-5 PW column. One of the inhibitors was identified both as the monomeric and dimeric forms of stefin B. Two others, called cysteine proteinase inhibitor-1 and cysteine proteinase inhibitor-2, were N terminally blocked and most likely belong to the stefin family. The complete amino acid sequence of the last inhibitor, namely bovine stefin C, was determined. The inhibitor consisted of 101 amino acids and its M(r) was calculated to be 11,546. It exhibits considerable sequence homology with other inhibitors from the stefin family. It was identified as the first tryptophane-containing stefin and it had a prolonged N terminus. The four inhibitors had similar inhibitory activities on cysteine proteinases. They were fast-acting inhibitors of papain and cathepsin L (kass > or = 1.8 x 10(6) M-1 s-1) and formed very tight complexes with the enzymes (Ki < or = 180 pM). In contrast, they were relatively poor inhibitors of cathepsin B (Ki > 100 nM).

Internal energy distributions deposited in doubly and singly charged tungsten hexacarbonyl ions generated by charge stripping, electron impact, and charge exchange.

The distribution Pε of internal energies deposited in W(CO)6 (+•). ions upon charge stripping (that is, electron detachment to yield the doubly charged ion in the course of a single kiloelec-tronvolt energy collision) was estimated by a thermochemical method from the measured relative abundances of the doubly charged fragment ions produced. The thermochemical information needed to estimate P/ge was obtained by measuring the threshold translational energy losses associated with charge stripping of the singly charged fragment ions, W(CO) n (+) (n = 0-5). The P(/ge) curve falls exponentially with increasing internal energy. The average energy transferred to W(CO)6 (+•) upon a 7.8-keV collision with O2 is 19 eV, yielding W(CO)6 (2•) ions with an average of 4 eV of internal energy. In its general appearance, the P(ε) distribution associated with charge stripping is similar to the curves obtained from simple collisional activation of either W(CO) 6 (+•). or W(CO)6 (2+•) in kiloelectronvolt energy gaseous collisions. Given that charge stripping occurs by way of an electronic excitation process, this similarity in the energy deposition function is taken to indicate that electronic excitation is also the major mechanism for simple collisional activation in this system at zero scattering angle in the kiloelectronvolt energy regime. The internal energy distribution associated with a related charge-stripping process, charge inversion from the metal carbonyl anions to yield the corresponding cations, was also recorded. This reaction shows a large (∼7 eV) average internal energy deposition with a distribution that indicates near-zero probability of formation of unexcited ions. These data are tentatively interpreted in terms of vibrationalelectron detachment. The internal energy distribution associated with an exothermic process, charge exchange [W(CO)6 (2+•) + O2 → W(CO) + (6•)+O2 (+•)], was also characterized. Unexpectedly strong coupling of translational to internal energy is observed, and there is a large probability of depositing internal energies in excess of 10 eV, even though the exothermicity is only 3 eV. Finally, the internal energy distributions associated with the formation of doubly charged W(CO)6 (2+•) ions by electron ionization have been measured. Unlike the distribution for charge stripping, but like that for singly charged ions generated by electron impact, this distribution shows considerable structure, presumably due to Franck-Condon factors.

Bioconversion of steroid glycosides by Nocardia restricta.

The bioconversion of steroid alkaloid tomatine by Nocardia restricta yields the conjugate with lactic acid. We studied the bioconversion of some steroid glycosides without a nitrogen atom in the molecule to determine the effect of the nitrogen atom. The glycosides were of three different types: sterol glycosides, bufadienolide rhamnoside and steroid saponine. The results of bioconversions showed that Nocardia restricta converts steroid glycosides differently according to the sugar bound to the steroid aglycone. It can be concluded that in the absence of a nitrogen atom in the steroid molecule no conjugation with lactic acid by Nocardia restricta occurs.

Determination of submicrogram quantities of cimetidine and its biotransformation and degradation products.

The new and convenient method for the separation, isolation and characterization of the N-ciano-N'-methyl-N"-(2-/(5-methylimidazol-4-yl)methylthio/ethyl) guanidine and its biotransformation and degradation products was developed. Mass spectra obtained with the FAB (Fast Atom Bombardment) method are described. This method proved to be very successful for the analysis and characterization of studied compounds.