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PubMed2005

The liquidlike ordering of lipid A-diphosphate colloidal crystals: the influence of Ca2+, Mg2+, Na+, and K+ on the ordering of colloidal suspensions of lipid A-diphosphate in aqueous solutions.

A comprehensive study was performed on electrostatically stabilized aqueous dispersion of lipid A-diphosphate in the presence of bound Ca2+, Mg2+, K+, and Na+ ions at low ionic strength (0.10-10.0-mM NaCl, 25 degrees C) over a range of volume fraction of 1.0 x 10(-4)< or =phi< or =4.95 x 10(-4). These suspensions were characterized by light scattering (LS), quasielastic light scattering, small-angle x-ray scattering, transmission electron microscopy, scanning electron microscopy, conductivity measurements, and acid-base titrations. LS and electron microscopy yielded similar values for particle sizes, particle size distributions, and polydispersity. The measured static structure factor, S(Q), of lipid A-diphosphate was seen to be heavily dependent on the nature and concentration of the counterions, e.g., Ca2+ at 5.0 nM, Mg2+ at 15.0 microM, and K+ at 100.0 microM (25 degrees C). The magnitude and position of the S(Q) peaks depend not only on the divalent ion concentration (Ca2+ and Mg2+) but also on the order of addition of the counterions to the lipid A-diphosphate suspension in the presence of 0.1-microM NaCl. Significant changes in the rms radii of gyration (R2G) 1/2 of the lipid A-diphosphate particles were observed in the presence of Ca2+ (24.8+/-0.8 nm), Mg2+ (28.5+/-0.7 nm), and K+ (25.2+/-0.6 nm), whereas the Na+ salt (29.1+/-0.8 nm) has a value similar to the one found for the de-ionized lipid A-diphosphate suspensions (29.2+/-0.8 nm). Effective particle charges were determined by fits of the integral equation calculations of the polydisperse static structure factor, S(Q), to the light-scattering data and they were found to be in the range of Z*=700-750 for the lipid A-diphosphate salts under investigation. The light-scattering data indicated that only a small fraction of the ionizable surface sites (phosphate) of the lipid A-diphosphate was partly dissociated (approximately 30%). It was also discovered that a given amount of Ca2+ (1.0-5.0 nM) or K+ (100 microM) influenced the structure much more than Na+ (0.1-10.0-mM NaCl) or Mg2+ (50 microM). By comparing the heights and positions of the structure factor peaks S(Q) for lipid A-diphosphate-Na+ and lipid A-diphosphate-Ca2+, it was concluded that the structure factor does not depend simply on ionic strength but more importantly on the internal structural arrangements of the lipid A-diphosphate assembly in the presence of the bound cations. The liquidlike interactions revealed a considerable degree of ordering in solution accounting for the primary S(Q) peak and also the secondary minimum at large particle separation. The ordering of lipid A-diphosphate-Ca2+ colloidal crystals in suspension showed six to seven discrete diffraction peaks and revealed a face-centered-cubic (fcc) lattice type (a=56.3 nm) at a volume fraction of 3.2 x 10(-4)< or =phi< or =3.9 x 10(-4). The K+ salt also exhibited a fcc lattice (a=55.92 nm) at the same volume fractions, but reveals a different peak intensity distribution, as seen for the lipid A-diphosphate-Ca2+ salt. However, the Mg2+ and the Na+ salts of lipid A-diphosphate showed body-centered-cubic (bcc) lattices with a=45.50 nm and a=41.50 nm, respectively (3.2 x 10(-4)< or =phi< or =3.9 x 10(-4)), displaying the same intensity distribution with the exception of the (220) diffraction peaks, which differ in intensity for both salts of lipid A-diphosphate.

Calcium↗
PubMed2002

Role of the tongue base suspension suture with The Repose System bone screw in the multilevel surgical management of obstructive sleep apnea.

OBJECTIVE: The Repose System (tongue base suspension) is a new, minimally invasive technique for tongue base suspension in the treatment of obstructive sleep apnea. The purpose of this project was to describe our preliminary experience using this tongue base suspension system in conjunction with uvulopalatopharyngoplasty (UPPP) in the multilevel surgical approach to the management of obstructive sleep apnea (OSA). STUDY DESIGN: We conducted a retrospective analysis of 19 consecutive patients undergoing UPPP and The Repose System tongue base suspension for the management of obstructive sleep apnea during a 1-year period (1998 through 1999). RESULTS: Fifteen patients (11 men and 4 women) had complete preoperative and postoperative polysomnographic data. A 46% reduction in the preoperative respiratory disturbance index (RDI) (38.7 +/- 12.3) versus the postoperative RDI (21.0 +/- 7.4, P < 0.05) was demonstrated at a mean of 3.8 months after surgery. The apnea index demonstrated a 39% reduction. The surgical cure rate was 20% (3 of 15 patients). CONCLUSIONS: The Repose System in conjunction with UPPP has been shown to produce significant reductions in the RDI and apnea index as well as a significant increase in O2 saturation. Despite the improvement in these objective parameters, the overall surgical cure rate was only 20% (3 of 15 patients) in this retrospective series. Further research is warranted to define the role of The Repose System in the management of obstructive sleep apnea patients with multilevel airway obstruction.

Bone Screws↗
PubMed2000

Bilateral uterosacral ligament vaginal vault suspension with site-specific endopelvic fascia defect repair for treatment of pelvic organ prolapse.

OBJECTIVE: The anatomic and functional success of suspension of the vaginal cuff to the proximal uterosacral ligaments is described. STUDY DESIGN: Forty-six women underwent vaginal site-specific repair of endopelvic fascia defects with suspension of the vaginal cuff to the proximal uterosacral ligaments for pelvic organ prolapse. Outcome measures included operative complications, pelvic organ prolapse quantitation, and assessment of pelvic floor symptoms. RESULTS: After a median follow-up of 15.5 months (range, 3.5 months-3.4 years), 90% of patients had both resolution of vaginal bulging or prolapse symptoms and improvement of the stage of prolapse. There were improvements in all pelvic organ prolapse quantitation measurements except for total vaginal length, for which the median decrease was 0.75 cm. Intraoperatively, ureteral occlusion was noted in 11% (5/46) of patients with universal cystoscopy. In 3 patients the uterosacral suspension sutures were removed and replaced with resolution of the occlusion and in 2 patients ureteral reimplantation was required. Symptomatic prolapse (2 apical segment, 1 anterior, and 1 posterior) developed in 4 patients (10%), and 3 of them underwent reoperation. There were significant improvements in symptoms of bulging and pressure, voiding dysfunction, and vaginal and perineal splinting. CONCLUSION: Suspension of the vaginal vault to the proximal uterosacral ligaments combined with site-specific repair of endopelvic fascia defects provides excellent anatomic and functional correction of pelvic organ prolapse in most women. The risk of ureteral injury with this technique makes intraoperative cystoscopy essential.

Adult↗
PubMed1976

Preparation of metabolically active cell suspensions from wool roots.

A method is described for the preparation of metabolically active cell suspensions from plucked wool roots using the proteolytic enzyme trypsin. The suspensions consist of a heterogeneous population of cells which appear similar in morphology to follicle bulb cells, differentiating keratinocytes and possibly cells of the inner root sheath. The concentrations of trypsin and of inorganic ions for optimum activity of the suspensions have been determined, and the inclusion of EGTA was found to increase the yield of cells. The cell suspensions incorporate [14C]leucine, [3H]uridine and [3H]thymidine into acid-insoluble products, and are sensitive to the action of cycloheximide and emetine, but not to chloramphenicol or rifampin. Autoradiography has shown that the cells believed to be derived from the follicle bulbs show the greatest activity.

Animals↗
PubMed2004

Squamous cell carcinoma cell aggregates escape suspension-induced, p53-mediated anoikis: fibronectin and integrin alphav mediate survival signals through focal adhesion kinase.

Resistance to anoikis, or apoptosis triggered by detachment from the extracellular matrix (ECM), lengthens the survival of malignant cells, facilitating reattachment and colonization of secondary sites. To examine the molecular mechanisms underlying resistance to anoikis in human oral squamous cell carcinoma (SCC) cells, we cultured human squamous carcinoma (HSC-3) cells in suspension on plates coated with poly-2-hydroxyethyl methacrylate, which blocks access to the ECM. Cells in suspension that formed multicellular aggregates had significantly lower levels of apoptosis than single cells. Aggregates, but not single cells, had high levels of fibronectin. Preincubation with a cyclic arginine-glycine-aspartic acid peptide or fibronectin-blocking antibody significantly increased anoikis. Single cells had markedly lower expression of the integrin alpha(v) receptor than aggregates. Blocking alpha(v) function with a blocking antibody or by transfection with an antisense oligonucleotide increased apoptosis and inhibited aggregation. In single cells but not aggregates, phosphorylation of the integrin-associated focal adhesion kinase (FAK) at tyrosine 397 was reduced, and p53 levels were increased. Apoptosis was increased by blocking FAK with an antisense oligonucleotide and reduced by blocking p53. These findings show that SCC cells escape suspension-induced anoikis by forming multicellular aggregates that avail themselves of fibronectin survival signals mediated by integrin alpha(v). Single cells in suspension that do not form aggregates undergo anoikis because of decreased FAK phosphorylation and increased p53 levels. Thus, SCC cells appear to use neighboring cells and the ECM molecule FN to promote the metastatic phenotype.

Animals↗
PubMed2003

Stimulation of betacyanin synthesis through exogenous methyl jasmonate and other elicitors in suspension-cultured cells of Portulaca.

Betacyanin production in suspension-cultured cells of Portulaca was significantly enhanced by both abiotic and biotic elicitors. Betacyanin levels increased 1.3 and 1.5-fold over the controls in the presence of two abiotic elicitors (20 mumol/L CuSO4 and 100 mumol/L FeEDTA) and increased 1.8 and 1.6-fold in the presence of two biotic elicitors (0.5 mg/L beta-glucan and 0.5 mg/L chitosan). Maximum betacyanin synthesis with the two most effective elicitors was obtained when cultures were treated on day 1 and day 0 by beta-glucan and FeEDTA, respectively. A concentration-dependent response was exhibited by cultures treated with exogenous methyl jasmonate (MJ). MJ alone at 0.1 mumol/L caused a 2.6-fold increase in betacyanin synthesis when administered to the suspension culture on day 3. However, no additive effect on betacyanin accumulation was observed in treatments, which combined MJ and beta-glucan or FeEDTA. Treatment with ibuprofen (IB), an inhibitor of jasmonate biosynthesis, reduced the level of betacyanin in cells cultured in standard medium at all concentrations tested (25, 50, 100 mumol/L). The effect of IB on betacyanin synthesis in the cells treated with MJ or beta-glucan, however, differed with the IB concentration applied. The two higher concentrations (50 and 100 mumol/L) of IB significantly reduced the betacyanin content while the lower concentration (25 mumol/L) did not show an adverse effect on the betacyanin enhancement triggered by MJ or beta-glucan. Our findings suggest that, in suspension-cultured cells of Portulaca, an MJ-mediated signal transduction pathway prominently exists in betacyanin synthesis. This pathway seems to act antagonistically towards beta-glucan-mediated signaling. As far as we know this is the first report on the elevation of betacyanin level by jasmonate or other elicitors in cell suspension cultures.

Acetates↗
PubMed1998

Metabolic activity of fresh and cryopreserved dog hepatocyte suspensions.

1. Dog hepatocytes were cryopreserved at 6 x 10(6) viable cells/ml in a suspension buffer containing 10% DMSO and were stored in liquid nitrogen. 2. The exclusion of trypan blue dye was 96 +/- 2 and 85 +/- 9% in fresh and cryopreserved (CP) hepatocytes, respectively. Albumin synthesis was unaffected by freezing. 3. Ethoxycoumarin and ethoxyresorufin O-deethylase activities were equivalent in fresh and CP hepatocytes. 4. The profile of testosterone metabolism was unaffected by freezing. Total hydroxylase activities were 815 +/- 33 pmol/min/10(6) cells in freshly isolated whole hepatocytes and 463 +/- 24 pmol/min/10(6) CP whole hepatocytes, but they were equivalent in fresh and CP hepatocyte homogenates supplemented with 250 microM NADPH. 5. Phase 2 enzymes were functional in freshly thawed CP hepatocytes but they required exogenous addition of cofactors (20 microM UDPGA and 1.7 microM PAPS). 6. When placed in suspension for longer times, fresh and CP cell viabilities were 88 +/- 6 and 64 +/- 2% after 4 h. ECOD and EROD activities were equivalent in fresh and CP hepatocyte suspensions, over 4 h. Testosterone hydroxylase activities were well maintained in fresh cell suspensions but they declined to 63 +/- 6% of the initial activity after 4 h in CP hepatocytes. 7. These results indicate that CP dog hepatocytes are a suitable in vitro system for xenobiotic metabolism since enzyme functions in CP hepatocytes were stabilized. Cofactors in freshly thawed CP hepatocytes should be measured and controlled for optimal use.

Albumins↗
PubMed2006

Effect of suspension systems on the physiological and psychological responses to sub-maximal biking on simulated smoothand bumpy tracks.

The aim of this study was to compare the physiological and psychological responses of cyclists riding on a hard tail bicycle and on a full suspension bicycle. Twenty males participated in two series of tests. A test rig held the front axle of the bicycle steady while the rear wheel rotated against a heavy roller with bumps (or no bumps) on its surface. In the first series of tests, eight participants (age 19-27 years, body mass 65-82 kg) were tested on both the full suspension and hard tail bicycles with and without bumps fitted to the roller. The second series of test repeated the bump tests with a further six participants (age 22-31 years, body mass 74-94 kg) and also involved an investigation of familiarization effects with the final six participants (age 21-30 years, body mass 64-80 kg). Heart rate, oxygen consumption (VO(2)), rating of perceived exertion (RPE) and comfort were recorded during 10 min sub-maximal tests. Combined data for the bumps tests show that the full suspension bicycle was significantly different (P < 0.001) from the hard tail bicycle on all four measures. Oxygen consumption, heart rate and RPE were lower on average by 8.7 (s = 3.6) ml . kg(-1) . min(-1), 32.1 (s = 12.1) beats . min(-1) and 2.6 (s = 2.0) units, respectively. Comfort scores were higher (better) on average by 1.9 (s = 0.8) units. For the no bumps tests, the only statistically significant difference (P = 0.008) was in VO(2), which was lower for the hard tail bicycle by 2.2 (s = 1.7) ml . kg(-1) . min(-1). The results indicate that the full suspension bicycle provides a physiological and psychological advantage over the hard tail bicycle during simulated sub-maximal exercise on bumps.

Adult↗
PubMed2001

Marking of nonpalpable breast lesions using a custom carbon suspension.

PURPOSE: To review results of carbon marking in non-palpable breast lesions using a different type of a carbon suspension containing 0.5% polyoxyethylene sorbitan monooleate (PSM). MATERIAL AND METHODS: Sixteen lesions of 16 patients with indeterminate or suspicious mammographic findings underwent stereotaxic carbon marking. With the aid of tracing of the carbon stains surgery was then performed. RESULTS: Pathology revealed malignancy in 26% of the cases and the missed rate by carbon marking was 6% (1 lesion). Carbon marking is an easier application compared to hook-wire systems in localizing occult breast lesions. PSM added to a 4% carbon suspension results in a more homogeneous suspension, prevents early precipitation and eases injection. Animal studies have shown that no local or peripheral tissue reactions are elicited with either pure PSM or in a mixture with carbon. CONCLUSION: We recommend addition of PSM to carbon marking suspensions.

Adult↗
PubMed2000

Characterization and quantitation by flow cytometry of membranous microparticles formed during activation of platelet suspensions with ionophore or thrombin.

The typical data presentation by flow cytometry of platelet suspensions stimulated with calcium ionophore A-23187, thrombin, C5b-9, or other agonists shows a unimodal decrease (or 'left-shift') in forward angle light scatter. Many reports in the literature interpret these findings as indicative of the appearance of small membranous microparticles generated from the platelets as part of the activation response. Investigators may attempt to quantify the microparticles by calculation of the percentage of counts falling below a gate set around the forward angle light scatter distribution of fresh, non-activated platelets. We believe that this approach can lead to erroneous results unless the total particle count in the sample is also determined. The true change in total particle count in a platelet sample is easily estimated on the flow cytometer by adding a known amount of fluorescent beads to the platelet suspension and noting a change in the ratio of bead versus non-bead event counts as a result of the stimulus added. Using this technique under settings considered routine for platelet analysis on a FACScan flow cytometer (Becton-Dickinson), we have found that particle counts increased very little (less than a doubling) in platelet suspensions stimulated with 1-10 microM A-23187 or 0.01-0.5 U/ml thrombin or with sera from patients with diagnosed heparin-induced thrombocytopenia (HIT). Only by employing high sensitivity settings for signal thresholding on orthogonal light scatter, combined with fluorescence gating on high prevalence surface antigens, were we able to detect significant increases (5- or 6-fold) in total particle count in the same experiments. The new events we observed were separated by a decade or more (log scale) from intact platelets on the light scatter plots and fluorescence histograms in a bimodal distribution. We postulate that the unimodal-shifted population of events seen under routine settings after stimulation with ionophore is really degranulated platelets, and only the much smaller new modal subpopulation represents microparticles released as new entities into the platelet suspension. We conclude that without high sensitivity settings for data acquisition, it is most likely incorrect to claim that the left-shifted events on flow cytometry light scatter plots appearing contiguous with the distribution of activated platelets are released microparticles.

Blood Platelets↗
PubMed2001

Fluorescence in situ hybridization of metaphase chromosomes in suspension.

PURPOSE: To describe a new method for FISH analysis of metaphase chromosomes in suspension. MATERIALS AND METHODS: Metaphase chromosomes in suspension were isolated from a Chinese hamster human hybrid cell line, 314-2 (1) Y, and a human cell line, GM 130B. During suspension hybridization, specific chromosomes were labeled from these two cell lines using either biotin-labeled human genomic DNA, a directly labeled human pancentromere DNA probe or a chromosome #1 locus-specific probe. RESULTS: The method allows, for the first time, recovery of large numbers of isolated individual hybridized chromosomes with good morphology for both human x hamster hybrid and human cell lines. The results showed that 46-73% of the starting number of total chromosomes can be recovered after a FISH in suspension procedure. The well-preserved morphology of hybridized metaphase chromosomes allowed (1) rapid detection of individual human and hamster chromosome aberrations, (2) rapid counting of the painted human chromosomes and (3) fast, clear detection of chromosome region-specific probes. This method offers a new tool to assay chromosomes and DNA: it offers the possibility to develop new techniques for sorting chromosomes based on FISH signals, for early detection and screening of genetic diseases and for bulk measurement of both balanced or unbalanced chromosomal exchanges and rearrangements. CONCLUSION: The potential of the method described should facilitate fast, sensitive population monitoring, and increase sensitivity of the measurements in chromosome-based biodosimetry.

Animals↗
PubMed2003

Effect of high starting dose of budesonide inhalation suspension on serum cortisol concentration in young children with recurrent wheezing episodes.

INTRODUCTION: There are no available data on the safety of recommended schedules for the initiation of treatment with budesonide inhalation suspension in children with recurrent wheezing episodes. We compared the safety of high and low starting dose of budesonide by measuring their effect on plasma cortisol concentration. METHODS: A randomized double-blind, placebo-controlled design was used. Twenty-nine children ages 6 months to 3 years were divided into three groups: (1) high starting dose: 1 mg budesonide inhalation suspension twice daily followed by a stepwise decrease of 25% every second day for 8 days (n = 11); (2) low starting dose: 0.25 mg twice daily for 8 days (n = 11); (3) placebo (n = 7). The 8 AM (fasting) and 1-hour post-ACTH stimulation plasma cortisol concentrations were measured before and 10 days after initiation of budesonide treatment. RESULTS: Before treatment and after 8-10 days of treatment, there was no significant difference in mean serum cortisol concentration in the high starting dose, low-dose and placebo groups, either at 8 AM or at 1 hour after ACTH stimulation. CONCLUSION: The administration of nebulized suspension of budesonide at a high starting dose (2 mg/day for 2 days) followed by a rapid stepwise decrease over 8 days was safe, causing similar changes in serum cortisol levels to low-dose budesonide suspension or placebo.

Administration, Inhalation↗
PubMed1973

A technique for ultracryotomy of cell suspensions and tissues.

Ultracryotomy of fixed tissue has been investigated for a number of years but, so far, success has been limited for several reasons. The simple technique herein reported allows the ultracryotomy not only of a variety of tissues but also of single cells in suspension, with a preservation and visualization of ultrastructural detail at least equivalent to that obtained with conventional embedding procedures. In this technique, sucrose is infused into glutaraldehyde-fixed tissue pieces before freezing for the purpose of controlling the sectioning consistency. By choosing the proper combinations of sucrose concentration and sectioning temperature, a wide variety of tissues can be smoothly sectioned. Isolated cells, suspended in a sucrose solution, are sectioned by sectioning the frozen droplet of the suspension. A small liquid droplet of a saturated or near-saturated sucrose solution, suspended on the tip of an eyelash probe, is used to transfer frozen sections from the knife edge onto a grid substrate or a water surface. Upon melting of the sections on the surface of the sucrose droplet, they are spread flat and smooth due to surface tension. When the section of a suspension of single cells melts, individual sections of cells remain confined to the small area of the droplet surface. These devices make it possible to cut wide dry sections, and to avoid flotation on dimethyl sulfoxide solutions. With appropriate staining procedures, well-preserved ultrastructural detail can be observed. The technique is illustrated with a number of tissue preparations and with suspensions of erythrocytes and bacterial cells.

Aldehydes↗
PubMed1972

Inhibitory and stimulatory effects of concanavalin A on the response of mouse spleen cell suspensions to antigen. I. Characterization of the inhibitory cell activity.

The presence of concanavalin A (Con A) inhibits the immune response of mouse spleen cell suspensions to erythrocyte antigens, stimulates the incorporation of tritiated thymidine, and increases cell recovery. Con A also restores the depressed response of cell preparations treated to remove thymus-derived cells. The dose-response curve for all four effects shows peak activity at 2 microg/ml. The depressed in vitro response of spleen cell suspensions from adult thymectomized, irradiated, bone marrow-restored mice is also restored by Con A. Here the dose-response curve is quite different with activity over a much wider range of concentration. The restoration of thymus-derived cell-depleted cultures by Con A is inhibited by the addition of untreated, unirradiated, mouse spleen cell suspensions, but is not inhibited by untreated, irradiated cells. Small numbers of spleen cells that have been preincubated with Con A and washed will inhibit the response of fresh, untreated cells to antigen. If the mouse spleen cell suspensions are incubated for 24 hr before the addition of Con A, the response to antigen is no longer inhibited but is stimulated instead. The data are compatible with the hypothesis that there are at least two cell targets for the action of Con A. One cell, that mediates the inhibitor effect, is a short-lived, radiosensitive, thymus-derived cell. The other cell, that mediates the stimulating effect, cannot be identified from the data presented here but may also be of thymus origin on the basis of studies by other investigators.

Animals↗
PubMed2005

Use of suspension traction system for renal positioning during laparoscopic partial nephrectomy.

BACKGROUND AND PURPOSE: The technical difficulty of laparoscopic partial nephrectomy (LPN) lies mainly in the steps required during warm ischemia time (WIT), which includes tumor excision and renal reconstruction. We present a renal-suspension traction system to place the tumor in stable optimal view during the critical steps of LPN. PATIENTS AND METHODS: Thirty-three patients underwent LPN from October 2002 through December 2003. Eight had a renal sling placed intraoperatively because of difficult access to the tumor. Perioperative parameters were assessed. The renal hilum was dissected and the tumor exposed. To keep the tumor oriented perfectly toward the camera and the working ports, a 2-0 braided polyglactin (Vicryl) traction suture was passed through Gerota's fascia, catching the renal capsule; brought out through the abdominal wall; and secured to the skin with a clamp. RESULTS: All surgical margins were negative. For the traction and nontraction groups, the mean sizes of the tumor were 2.5 cm and 2.2 cm, respectively (P = 0.426). The estimated blood loss was 125 mL and 246 mL respectively (P = 0.041). The WIT average 27.4 minutes and 30.12 minutes (P = 0.470). The surgical time was 192 minutes and 235 minutes respectively, (P = 0.062). Based on our findings, we have devised a renal suspension traction algorithm for specific tumor locations during LPN. CONCLUSIONS: The renal suspension traction system allows precision in tumor excision and renal reconstruction during the critical steps of LPN. With the renal suspension system we devised, we are able to simplify LPN for tumors located away from optimal port access.

Carcinoma, Renal Cell↗
PubMed1981

Tissue immunomicroscopic evaluation of monoclonality of B-cell lymphomas: comparison with cell suspension studies.

A series of 80 tissues removed from patients having a variety of lymphoproliferative disorders were comparatively studied by cell suspension and cryostat frozen section tissue immunomicroscopic technics. Of 39 cases of non-Hodgkin's lymphomas studied by cell suspension, only 18 had surface immunoglobulins (SIg) markers consistent with monotypia (46%). Conversely, immunohistochemistry showed 18 cases (92%). Among the 18 cases in which there was no correlation between immunohistochemistry and cell suspension studies (46%), a variety of cytologic variants of non-Hodgkin's lymphomas was recognized, including nodular poorly differentiated lymphocytic lymphoma, nodular large cell lymphoma, and a soft tissue plasmacytoma. The lack of correlation between the two technics may be due to several different mechanisms, including the selective enrichment of the suspension by nonneoplastic cell populations resulting in a sampling artifact, the disappearance of endogenous SIg in large or plasmacytoid lymphocytes, and the presence of membrane-bound exogenous polyclonal SIG. Immunohistochemistry represents a reliable, simple technic for establishing monotypia in non-Hodgkin's B-cell lymphomas.

Antibodies, Neoplasm↗
PubMed1990

An automated method to prepare cell suspensions from human biopsy samples for immunophenotyping by flow cytometry.

A comparison was made between a manual and automated method for preparing single cell suspensions from various types of human biopsy samples. The automated method uses the shearing action of fluid movement generated by a reciprocating paddle system. When compared on 11 samples, the automated instrument always isolated cells in less time, usually requiring only 15-30 seconds in contrast to 10-15 minutes for the manual method. The time comparisons involved "set up" time of the required minor equipment as well as the time to make a complete single cell suspension from the portion of the biopsy sample sent to the Flow Cytometry Lab so extra cells could be used for other purposes and cryogenically stored for future reference. Cells isolated by the automated method from various B-lymphocytic and T-lymphocytic malignancies were still viable and could be successfully immunophenotyped by flow cytometry. The immunophenotyping results were compared for both cell isolation methods on seven of these samples, and the results were comparable. The automated technique has now been used to satisfactorily immunophenotype more than 50 biopsy samples. The automated method should represent a significant aid for clinical flow cytometry laboratories performing immunophenotyping tests by efficiently preparing single cell suspensions in a few seconds instead of minutes. Furthermore, the automated method uses a closed sterile bag system that helps minimize the exposure of personnel to potential infectious material present in biopsy samples and prevents external contamination of cell suspensions. The automated technique proven successful for immunophenotyping may also be helpful for related procedures involving hematopoietic malignancies such as DNA content analysis and cell functional assays by flow cytometry, as well as other assays such as tissue typing, gene probe, and in vitro chemosensitivity assays.

Antigens, CD↗
PubMed1993

The effect of seat suspension on exposure to whole-body vibration of professional drivers.

In this study the effectiveness of the seat suspension on the transmission of whole-body vibration through the driver's seat has been determined. Eleven types of seat frequently used in lorries, agricultural tractors and fork-lift trucks were selected. The transmissibility coefficient of each seat was measured by the ratio of the acceleration (weighted root-mean-square in the vertical axis) at the interface between the seat surface and the human body to the vibration at the attachment points of the seat on the vehicle floor. Measurements in the laboratory, using standardized representative vehicle vibration spectra and two volunteers of different weights, showed transmissibility coefficients of 0.34-1.28. Attenuation of the vibration input spectrum was obtained in 20 out of 24 (83%) measurements. Measurements in the field, conducted in vehicles under representative working conditions, showed transmissibility coefficients of 0.60-1.45. Attenuation of the vibration spectrum was obtained in 17 out of 24 (71%) vehicle-seat combinations. No significant differences were observed between seats with conventional suspension and those with air suspension. Laboratory measurements of the dynamic response of the seat suspension did not provide an adequate basis for predicting its performance in the field. In most work situations the magnitude and duration of vibration-exceeded the 8 h fatigue-decreased proficiency boundary of 0.32 m s-2 in the vertical axis, which indicates that in many working situations with a daily exposure of 8 h or more suspended seats will not protect professional drivers from harmful exposure to whole-body vibration.

Humans↗