Min Of Collection Research Articles

Plastic Syringes Instead of Heparin-added Dedicated Syringes for Blood Gas Analysis: A Prospective Observational Study.

Blood gas analysis is an important test for making quick and important clinical decisions, and it is recommended that a dedicated syringe that contains heparin be used to measure blood gas. We hypothesized that a plastic syringe could be used as a less-expensive substitute for a dedicated syringe, given that the test is performed immediately after collection. This single-center, prospective, observational study involved patients admitted to the Kanoya Medical Center (Kagoshima, Japan) between July 2020 and March 2021, who were requiring blood gas analysis using a dedicated syringe under arterial line (A-line) monitoring. There were no exclusion criteria. Two samples were collected from each patient using a dedicated syringe, and one sample was collected using a plastic syringe. To determine clinical substitutability, Bland-Altman analysis was performed. A total of 60 samples from 20 consecutive patients were collected and assayed. The mean patient age was 72 years, and 75% patients were men. The 95% limit of agreement for pH, PCO2, PO2, Na, K, Ca, and SO2 were similar for both dedicated and plastic syringes. HCO3 and BE were significantly higher in the samples taken with plastic syringes, whereas Hb and Ht could not be measured accurately with any syringe. The use of plastic syringes in place of dedicated syringes is generally considered acceptable for most items considering that measurement is performed within 3 min of collection, and the cost of medical materials may be reduced. Regardless of the type of syringe, caution should be exercised in interpreting the results of measuring Hb and Ht using a blood gas analyzer.

Effects of a single subcutaneous dose of enoxaparin on veterinary viscoelastic coagulation monitor variables in healthy cats: Double blind, placebo controlled cross-over trial.

Cats placed on anticoagulant medication require frequent monitoring. The veterinary viscoelastic coagulation monitor (VCM-Vet) could provide a convenient and cost-effective monitoring, enabling therapeutic decision making. Enoxaparin will lead to changes in VCM-Vet variables and these will correlate with antiXa activity. Twenty-one healthy cats. Cats were randomized to receive either enoxaparin (1mg/kg) subcutaneously or 0.9% NaCl (equal volume) and crossed over with a 7-day washout period. The investigators were blinded to group allocation until data analysis. Jugular blood samples were drawn at time 0, and 2, 4, and 8hours after injection for VCM-Vet analysis within 2min of collection. Citrated plasma was frozen at -80°C for antiXa activity analysis. A Generalized Linear Model was completed to assess changes between baseline measurements and all time points. Significant differences between the enoxaparin-treated cats and controls at for T0h and T2h were found and presented as mean ± SD for clotting time (enoxaparin, 593.4 ± 78.0s; control, 448.5 ± 50.3s, P < .001), clot formation time (enoxaparin, 183.1 ± 41.7s; control, 155.4 ± 28.0s, P=.001), and alpha angle (enoxaparin, 52.4 ± 6.1°; control, 56.9 ± 3.7s, P=.003). AntiXa activity was significantly different between T0 and all other timepoints for the enoxaparin group (P < .001). There was no correlation between changes in clotting time and antiXa activity. The VCM-Vet detects a difference at 2hours after single-dose enoxaparin administration and it can be useful for anticoagulant therapy monitoring in cats.

Evaluation of Growing Turkey Blood Biochemistry Panel Measured Using the VetScan VS2

Point-of-care analyzers such as the Vetscan VS2 (VS2) that provide fast results are becoming an important tool in a variety of clinical and research settings. Several studies have explored the use of the VS2 to evaluate blood chemistry values in chickens; however, the VS2 analyzer has not yet been tested in turkeys. The first objective of this study was to utilize the VS2 to evaluate possible time-dependent changes in biochemical blood analytes over time, such as glucose, calcium, or sodium. Blood samples from 30 turkeys were analyzed with the VS2 at three time points (0, 15–20, and 40–60 min post collection), and it was found that the blood biochemistry values were stable when stored at 4 °C and analyzed within 60 min of collection. Next, we assessed the agreement between the VS2 portable analyzer and the reference benchtop analyzer (Cobas c501) and found that all of the blood analytes were comparable between both analyzers. Finally, we determined reference intervals using 120 blood samples collected from turkeys in the brooding period (0–7 days) and 118 samples collected from turkeys in the growing period (1–12 weeks). Although the values were compared to the published data, the understanding of any observed differences was challenging because reference intervals for the biochemical values in turkeys are limited, and the origin of these interval values could not be traced. Significant differences in the whole blood analytes were noted between brooding and growing birds. This study offers reassurance of the validity of the use of portable analyzers in the field for turkey veterinarians. We conclude that the VS2 can be used to measure biochemical analytes in turkeys and provide the first reference intervals for brooding and growing turkeys using this instrument.

False-positive flag of WBC and change of mean platelet volume (MPV) caused by K3-EDTA on the DxH 900 hematology analyzer

During the evaluation of the DxH 900 hematology analyzer (Beckman Coulter, Miami, FL), we noted that some patient samples produced a false positive white blood cell (WBC) flag, neutrophil blasts (NE-blast), despite the absence of abnormal cells. We investigated whether storage time or anticoagulants such as K2- or K3-ethylenediaminetetraacetic acid (EDTA) would affect complete blood count (CBC) tests on the DxH 900. Sixty-four whole blood samples were collected in K3-EDTA tubes, and 44 were simultaneously drawn in K2-EDTA tubes. Samples were tested at the following two intervals: within 30 min of collection (0 min) and after an additional 30 min of roller-mixing at room temperature (30 min). WBC differential dataplots in 0-min K3-EDTA tubes showed a mixed cell population between lymphocytes and neutrophils in 22 patients presenting the NE-blast flag. All 22 samples revealed normal WBC differential dataplots after 30 min of roller-mixing. The significantly lower mean neutrophil volume in specimens of 0-min K3-EDTA tubes than those of 0-min K2-EDTA, 30-min K2-EDTA and 30-min K3-EDTA tubes appear to be the cause of the false flag. Unlike blood cell counts, mean platelet volume (MPV) was significantly higher at 30 min using both EDTA tubes than that at 0 min. In conclusion, K3-EDTA can produce a false positive flag, NE-blast, on the DxH 900. MPV increases over time irrespective of EDTA salt type.

Effect of supplemental tracemineral source on bull semen quality

This study evaluated the effect of tracemineral supplementation on bull semen quality, as measured by computer-assisted sperm analysis. Angus and Gelbvieh × Angus bulls assigned to inorganic (n = 9) and organic (n = 10) trace-mineral treatments were maintained in drylot pens and fed mixed grass hay. Three times weekly bulls were individually fed rations containing either inorganic or a mixture of inorganic and organic Zn, Cu, Co, and Mn trace mineral for 123 d (mid-May to early September). Starting on d 60, semen was collected by electroejaculation weekly for a 9-wk period (mid-July until early September) and evaluated by computer-assisted sperm analysis for motility parameters within 5 min of collection. Data were analyzed by treatment, week, and their interaction using SAS PROC Mixed for repeated measures. Bulls supplemented with organic trace minerals had a greater (P = 0.02) percentage of motile sperm than those supplemented with inorganic trace minerals (65.5 vs. 56.1%, respectively). Likewise, percentage of progressive sperm was greater (P = 0.01) for bulls receiving organic (47.0%) versus only inorganic (38.4%) trace mineral. Sperm with rapid motility (path velocity >50 μm/s) was also greater (P = 0.03) for bulls supplemented with organic compared with bulls receiving inorganic trace mineral (62.3 vs. 52.8%, respectively). Sperm motility is the single most important semen quality parameter influencing bull fertility. Results suggest organic trace-mineral supplementation may improve bull semen quality. Additional studies are needed to determine whether this improvement in semen quality translates into improved pregnancy rates.

SIMULTANEOUS CONCENTRATION AND DETECTION OF ESCHERICHIA COLI USING CARBON NANOTUBE DEVICES

The performance of a nanoscale sensor is not limited by the sensitivity of the sensor itself but rather by the diffusion time required for target molecules to reach to the extremely small sensor surface. In this work, we developed a carbon nanotube device that performed the dual functions of concentrating and detecting microorganisms in a sample solution. The sensor surface area was increased by fabricating a carbon nanotube network device using thermal chemical vapor deposition and standard microfabrication techniques. The target Escherichia coli (E. coli) cells were concentrated at the sensor surface via dielectrophoretic concentration by the carbon nanotube network channels. After 10 min of collection, the chip was washed with ample amounts of a clean buffer solution, and only the E. coli cells that were bound to the antibodies remained on the sensor surface. The binding of E. coli to the CNT network device decreased the conductance, presumably due to an increase in the scattering at the sensor surface. The detection limit and the time required for microorganism detection was greatly improved by combining dielectrophoresis with the carbon nanotube devices.

Flow Cytometric Immunophenotyping of the Blood and CSF of Patients with Multiple Sclerosis (P02.081)

Objective: To monitor intrathecal immune responses and to investigate their role in pathogenesis of multiple sclerosis (MS). Background Immune cells in the cerebrospinal fluid (CSF) better reflect intrathecal inflammation than peripheral blood. However, low cellularity and susceptibility to apoptosis makes immunophenotyping of CSF challenging. Design/Methods: CSF and concomitant peripheral blood was collected in prospective manner in untreated patients (N=36) who presented for the diagnostic work-up of neuroimmunological disorder. Cells were isolated from 10-15cc of CSF within 15 min of collection. An optimized 12 color flow cytometric immunophenotyping (FCI) protocol was used to identify immune subpopulations (CD4, CD8 T cells, B cells, CD56bright- and CD56dim NK cells, monocytes, myeloid and plasmacytoid dendritic cells (DCs)) and their activation markers. FCI results were analyzed in an unbiased manner with the absolute cell count in blood and CSF and with the diagnosis established by the clinicians. Results: Upon unblinding, our cohort consisted of clinically isolated syndrome (CIS, N=2), relapsing-remitting MS (RR-MS, N=18), primary progressive MS (PP-MS, N=4), secondary progressive MS (SP-MS, N=4), non-inflammatory neurological diseases (NIND, N=4) and other inflammatory neurological diseases (OIND, N=5) controls. CSF was enriched for T cells, HLA-DR+ (i.e. activated) T cells and CD56bright NK cells in comparison to blood. We observed positive correlations between blood and CSF B cells, and blood and CSF HLA-DR+ T cells and terminally-differentiated double negative T cells, suggesting a link between systemic and intrathecal immune activation. Intrathecal differences between MS patients and controls consisted of elevated B cell to monocyte ratio (p=0.0004) and elevated CD4/CD8 T cell ratio (p=0.0007). Conclusions: The CSF immunophenotyping has been adapted to all NIB clinical protocols, including interventional trials, so updated results will be presented. We expect that with expanded cohort and longitudinal data, CSF immunophenotyping will provide essential information about intrathecal immune responses in neuroimmunological diseases. Supported by: NIH Intramural Research Program. Disclosure: Dr. Han has nothing to disclose. Dr. Salgado has nothing to disclose. Dr. Alfahad has nothing to disclose. Dr. Bielekova has received royalty payments from NIH.

A comparison of a portable blood lactate analyser and laboratory plasma analysis of blood samples from exercised horses

Quick, simple methods for blood lactate analysis could be helpful in evaluating xercise response in the field, but methods validated for analysis of blood collected after high intensity exercise in horses are scarce. The aim of the present study was to compare the results obtained using a commercial, portable blood lactate analyser with those from laboratory plasma analysis of blood samples from horses performing intensive exercise. Venous blood samples were collected from 220 horses within 5 min of performing exercise at a mean peak heart rate of 222 ±9 beats/min. The samples were kept chilled and analysed using portable analyser within 10 min of collection. Samples were also centrifuged and the plasma frozen (-20 °C) until analysed using an enzymatic and spectrophotometric laboratory lactate analysis. There was a significant (P&lt;0.05) correlation (R=0.94) between the methods at portable analyser values &lt;12.0 mmol/l, but at higher values there was no correlation. There was a significant effect of method (P&lt;0.0001) and portable analyser values were 21% lower than plasma lactate concentrations in the range 2.0-12.0 mmol/l. It is concluded that the portable analysis correlated well to a laboratory plasma analysis at portable analyser values &lt;12.0 mmol/l and that the portable analyser appears to be a safe method for lactate analysis during training conditions, when very high lactate concentrations are not expected. However, users should be aware that the results underestimate the corresponding plasma values by approximately 20%.

Microfluidic focal thrombosis model for measuring murine platelet deposition and stability: PAR4 signaling enhances shear-resistance of platelet aggregates.

Flow chambers allow the ex vivo study of platelet response to defined surfaces at controlled wall shear stresses. However, most assays require 1-10 mL of blood and are poorly suited for murine whole blood experiments. To measure murine platelet deposition and stability in response to focal zones of prothrombotic stimuli using 100 microL of whole blood and controlled flow exposure. Microfluidic methods were used for patterning acid-soluble collagen in 100 microm x 100 microm patches and creating flow channels with a volume of 150 nL. Within 1 min of collection into PPACK and fluorescent anti-mouse CD41 mAb, whole blood from normal mice or from mice deficient in the integrin alpha(2) subunit was perfused for 5 min over the patterned collagen. Platelet accumulation was measured at venous and arterial wall shear rates. After 5 min, thrombus stability was measured with a 'shear step-up' to 8000 s(-1). Wild-type murine platelets adhered and aggregated on collagen in a biphasic shear-dependent manner with increased deposition from 100 to 400 s(-1), but decreased deposition at 1000 s(-1). Adhesion to patterned collagen was severely diminished for platelets lacking a functional alpha(2)beta(1) integrin. Those integrin alpha(2)-deficient platelets that did adhere were removed from the surface when challenged to shear step-up. PAR4 agonist (AYPGKF) treatment of the thrombus at 5 min enhanced aggregate stability during the shear step-up. PAR4 signaling enhances aggregate stability by mechanisms independent of other thrombin-dependent pathways such as fibrin formation.

7 PLASMA PROGESTERONE CONCENTRATIONS IN OVARIECTOMIZED COWS WITH INTRAVAGINAL DEVICES CONTAINING DIFFERENT LEVELS OF PROGESTERONE

An experiment was designed to determine plasma progesterone (P4) concentrations in ovariectomized cows treated with either CIDR-B devices (Pfizer Animal Health, Hamilton, New Zealand) impregnated with 1.9 g of P4 or DIB devices (Syntex, Argentina) impregnated with 0.5 or 1.0 g of P4. Fifteen ovariectomized beef cows, weighing 350 to 450 kg and with a body condition score (BCS) 2.5 to 3.0 out of 5 were used. All cows were ovariectomized 30 days before the beginning of the trial and had plasma P4 concentrations &lt;1 ng/mL (measured by radioimmunoassay (RIA)) 10 days before the trial. On Day 0, cows were stratified by weight and randomly assigned to one of three treatment groups to receive intravaginal devices containing 0.5 g of P4 (DIB 0.5), 1 g of P4 (DIB 1.0), or 1.9 g of P4 (CIDR-B). Blood samples were taken 12 and 24 h after intravaginal device insertion and then every 24 h until device removal on Day 7. Jugular blood samples were drawn into heparinized tubes and centrifuged within 20 min of collection; the plasma was harvested, frozen, and stored at −10°C. Progesterone was measured in plasma samples using a commercial solid-phase RIA (Coat-a-count; Diagnostic Products Corp., Los Angeles, CA, USA). All of the samples were analyzed at one time and the intra-assay coefficient of variation was 13%. Plasma P4 concentrations were compared among treatments by calculating the area under the curve over time and testing for differences by ANOVA. Plasma P4 profiles were also analyzed by ANOVA for repeated measures. Analysis of plasma P4 profiles revealed a day effect (P &lt; 0.001) but not a treatment effect (P &gt; 0.13) or a day by treatment interaction (P &gt; 0.16; Table 1). The area under the curve did not differ (P = 0.95) among groups (DIB 0.5: 2236.4 ng, DIB 1.0: 2164.6 ng, and CIDR-B: 2266.8 ng). In all treatments, plasma P4 profiles were characterized by a sudden increase in P4 concentrations within 12 h of device insertion and a gradual decrease during the following several days. It was concluded that the use of CIDR-B devices impregnated with 1.9 g of P4 or DIB devices impregnated with 1.0 or 0.5 g of P4 did not result in different plasma P4 concentrations in ovariectomized cows. Further studies are needed to confirm these results in lactating and dry intact (not ovariectomized) cattle. Table 1. Mean plasma P4 concentrations (ng/mL ± SEM) in ovariectomized cows treated with intravaginal devices containing 0.5 g (DIB 0.5), 1.0 g (DIB 1.0), or 1.9 g (CIDR-B) of P4*

Effects of Anticoagulant and Time of Plasma Separation on Measurement of Homocysteine

Current interest in plasma total homocysteine (tHcy) measurements has increased with evidence that even mild hyperhomocysteinemia may be an independent risk factor for vascular disease (1) and that increases occur with vitamin deficiencies and reduced renal function. This has led to the investigation of problems associated with measurement, in particular the stability of tHcy after blood collection (2)(3). Transfer of homocysteine from red cells to plasma after venesection may occur and produce a 10% per hour increase in plasma tHcy concentrations (4), and thus influence assessments of the relative risk of disease (5). To reduce this increase, samples may be stored on ice and centrifuged within 1 h of collection. In epidemiologic surveys or even routine collection, this may not always be feasible. We studied the stability of plasma tHcy measured by a fluorescence polarization immunoassay (FPIA) in samples from 9 cystathionine β-synthase (CβS)-deficient homocystinuric patients and 13 healthy individuals. Blood was collected into both EDTA (1.8 g/L) and NaF (1.8 g/L EDTA and 3 g/L NaF) tubes. For six of the healthy individuals, we also used lithium heparin (14 kIU/L), sodium citrate (32 g/L trisodium citrate + 4.2 g/L citric acid; 3.2% solution), and ACD-B (13.2 g/L trisodium citrate + 5.25 g/L citric acid + 14.7 g/L glucose; 1.3% solution) tubes. The CβS-deficient patients were diagnosed and treated as described previously (6)(7), and the controls were healthy staff. Informed consent was obtained from all participants. Within 15 min of collection, samples were divided into five aliquots. One aliquot from each sample was centrifuged (10 000 g for 5 min) 15 min …

Capsaicin-evoked release of immunoreactive calcitonin gene-related peptide from rat trigeminal ganglion: evidence for intraganglionic neurotransmission

Chemically-mediated cross-excitation has been described between neurons within sensory ganglia. However, the identity and source of the chemical mediators is not known. Ca 2+-dependent release of neurotransmitters from cultured sensory neurons in vitro has been observed, although neurite outgrowth may confound the ability to extrapolate findings from culture systems to in vivo conditions. Thus, the present studies evaluate the hypothesis of capsaicin-sensitive intraganglionic neuropeptide release from freshly prepared slices of rat sensory ganglia. The ganglionic slice preparation provides an advantage over neuronal cultures, because release may be assessed within minutes after tissue collection (minimizing phenotypic changes) and while maintaining gross anatomical relationships. Trigeminal ganglia (TGG) were quickly removed from male, Sprague–Dawley rats (175–200 g), chopped into 200 μm slices and placed into chambers within 3 min of collection. Chambers were perfused with buffer, and superfusates were collected and assayed for immunoreactive calcitonin gene-related peptide (iCGRP) release via radioimmunoassay. After about 90 min of baseline collection, tissue was treated with capsaicin followed by a washout period. Capsaicin (1–100 μM) evoked concentration-dependent increases in iCGRP release. A competitive capsaicin receptor antagonist, capsazepine, significantly inhibited capsaicin-evoked release of iCGRP. In addition, capsaicin-evoked release of iCGRP was dependent on the presence of extracellular calcium. Furthermore, capsaicin-evoked release from TGG slices was significantly greater than that from slices of equivalent weights of adjacent trigeminal nerve shown histologically to be free of neuronal somata. These data support the hypothesis that Ca 2+-dependent exocytosis of neuropeptides may occur within the TGG in vivo and that the majority of this release derives from neuronal somata.

Speciation in North American Chickadees: II. Geography of mtDNA Haplotypes in Poecile carolinensis

The Carolina Chickadee (Poecile carolinensis) of southeastern North America comprises two geographically structured, monophyletic clusters of mitochondrial DNA (mtDNA) haplotypes (Gill et al. 1993). Here, we report the mtDNA identities of specimens of P carolinensis from new localities in southwestern Alabama west across southern Mississippi. The molecular identities of the new specimens define a clinal, not parapatric, transition from eastern haplotypes to western haplotypes. The results also document the first genetic cline structure between morphologically undifferentiated populations of a bird species. Methods.-Earlier specimens from a coarse sampling transect from Texas to Georgia (collected in 1990) revealed that the divergent R carolinensis haplotypes respectively occupy extensive ranges east and west of the Mobile Bay / Tombigbee River system of southwestern Alabama. These samples also focused attention on the Mobile Basin/ Tombigbee River as the place of contact and possibly parapatric transition from eastern to western haplotypes (Gill et al. 1993). To define the extent of coexistence of haplotypes and to test whether the contact was truly parapatric or a more gradual step cline, we collected additional specimens in February 1993 and February 1995, mostly from 10 new localities west from the Tombigbee River in southwestern Alabama and across the state of Mississippi (Fig. 1). We froze heart and liver samples within 30 min of collection. Specimens were preserved as traditional study skins and tissue vouchers in the collections of the Academy of Natural Sciences of Philadelphia. Sequence compositions of eastern versus western haplotypes differ by an estimated 2.7%, which is about one-half the divergence (5.2%) between R carolinensis and the Black-capped Chickadee (Poecile atricapillus). These unpublished divergence estimates are based on comparisons of 1,068 bp of the cytochrome-b gene from mitochondrial DNA (F. Gill, B. Slikas, and F. Sheldon unpubl. data). Earlier estimates of divergence based on calculations from

Progesterone metabolism during storage of blood samples from Gyr cattle: Effects of anticoagulant, time and temperature of incubation

Ten Gyr cows with a functional corpus luteum were used to evaluate the effects of time and temperature of incubation of blood samples on progesterone (P4) concentrations detected in plasma or serum. From each cow, a blood sample was collected into a flask containing no anticoagulant, another into an heparinized flask and a third into a flask containing sodium fluoride. The blood from each flask was divided into 46 aliquots. One of them was centrifuged within 5 min of collection. The remaining 45 aliquots were divided into three groups and kept at three different temperatures: 4°C, 17°C, or 37°C. For each anticoagulant, aliquots from every cow and incubation temperature were centrifuged every 30 min for 6 h, and then at 8, 12 and 24 h. Plasma or serum were separated immediately after centrifugation and were kept frozen at −20°C until assayed for progesterone. The mean initial concentration of P4 in serum (8.3 ng/ml) significantly diminished (P<0.05) to 6.7 ng/ml after 5 h of incubation at 4°C, 3 h at 17°C, or 2 h at 37°C. In plasma from heparinized blood the initial concentration (7.8 ng/ml) declined significantly after 6 h of incubation at 4°C, 2 h at 17°C, or 1 h at 37°C. Sodium fluoride used as anticoagulant prevented the degradation of P4 since the initial concentration of P4 (6.7 ng/ml) never declined during incubation at either 4°C or 37°C; the only significant reduction occurred after 24 h of incubation at 17°C.

Evaluation of Three Drop Traps for Sampling Aster Leafhoppers (Homoptera: Cicadellidae) in Rice

Three drop traps were developed and evaluated for sampling the aster leafhopper, Macrosteles fascifrons (Stal), in flooded rice paddies. The emergence trap collected the fewest number of leafhoppers per unit area. The transparent cylinder and plant sampler collected the greatest number of adults and nymphs per unit area, respectively. Use of the emergence trap and transparent cylinder required 5–10 min per sample for collection, identification, and enumeration. Each sample from the plant sampler required 10 min for collection, 24 h for processing in a Berlese funnel, and 5–10 min for identification and enumeration.

High-strength partially stabilized zirconia compact obtained by centrifugal consolidation

It has been reported that agglomerates present in ceramics powder limit the final density of the sintered compact [1, 2]. This is shown [3] to be due to different sintering kinetics between the inside and outside of an agglomerate and because the interagglomerate pores do not easily disappear even at the final stage of sintering. A technique of powder dispersion in liquid has been investigated [4] as a method for obtaining dense packing of powder particles. Rhodes [2] reported that a highly dense compact is obtained when agglomerates are eliminated by means of ultrasonic dispersion of powder followed by centrifuge cast. In the present study, the starting powder containing agglomerates is dispersed in aqueous solution by means of a highpower ultrasonic vibrator; then a centrifugal force is applied to the slurry, not only for the forced sedimentation, but for the effective compaction of powder. This is aimed at obtaining highly dense bulkcompacts to carry out the measurement of their flexural strength. PSZ powder used (Toyo Soda Co.) is co-precipitated ZRO:2(2.5) mol % Y203 (called 2Y and 2.5Y) having particle size of about 30 to 50 nm. The powder contains agglomerates of several to several tens of micrometres diameter. Firstly, the as-received powder was gently ground with an agate mortar for 15min. Then the powder dispersion was carried out in powder-to-solution ratio of 15g/15ml. For promoting dispersion, ultrasonic vibration (at 1 kW output) was applied to the slurry for 1⁄2h. Besides methanol as an effective organic dispersing solvent [5], Pierre [6] rep~)rted that the lowest viscosity is attained at pH = 1.2. In the present study, a sedimentation experiment was carried out for aqueous-HNO3 solution with different pH; the result suggests that solution at pH = 3 suspends the powder well with the least amount of sediments, as shown in Fig. 1. (Dispersion at pH = 11, 7, 3, 1.5 was tried and the porosities of the sintered compacts examined. The lowest porosity was obtained in the case of pH = 3.) Because undispersed agglomerates still remain after dispersion treatment, a sedimentation-classifying procedure was performed for reasons given below. The slurry was diluted 10 times and, after stirring, it was sedimented and the suspension was decanted. The lower centrifugal force (< 10000G) was applied for 10min for collection of the powder and the higher (20 000 G) force was applied for 30 min to the condensed slurry for final compaction. Much higher centrifugal force (200 000G) has been shown to result in

Quantitative aspects of the effect of somatostatin on bile flow in the rat [proceedings

Glycoprotein concentrations (0) were measured by a modification of the method of Mantle & Allen (1978). Viscosities were measured with an Ostwald viscometer at 25OC within 5min of collection of samples in order to minimize the observed fall in viscosity due to peptic action. Specific (v,,,, 0) and reduced specific viscosities (vred., A) are illustrated. Each point is an observation on a pooled sample from six cats. protein polymer to degraded subunit was much greater than in low-viscosity samples during infusion of pentagastrin alone. Over a period of time, endogenous pepsin split the glycoprotein polymer into subunits, and this was accompanied by a decrease in the viscosity of the juice. The increased viscosity with secretin infusion cannot be explained by a decrease in pepsin activity, since this doubled during the secretin infusion: also, the viscosity contribution from the pepsin was negligible. In conclusion, the mucus glycoprotein seen on infusion with pentagastrin alone is associated with predominately degraded glycoprotein subunits, and a low viscosity. This probably reflects the extra volume of gastric juice washing out previously degraded mucus from the stomach. With secretin, however, there is a large rise in the reduced and specific viscosity, and in the undegraded polymeric glycoprotein characteristic of the gel. This rise in undegraded glycoprotein in the juice, assuming no increase in mechanical erosion, is compatible with a genuine increase in mucus-gel secretion stimulated by secretin. These results also emphasize that measurements of the glycoprotein concentration or output in gastric juice alone cannot be directly equated with changes in the amount of the surface mucus gel.

Erythrocyte osmotic fragility in AKR mice with lymphoid leukaemia.

INVESTIGATIONS to characterize the anaemia occurring in mouse lymphoid leukaemia have recently involved a comparison of the erythrocyte osmotic fragility in mice of the low-leukaemia strain C5H, and the high-leukaemia strain AKR, using the technique of Creed1. Mice were bled under ether anaesthesia by cutting the axillary blood vessels and gently aspirating the blood with a wide-bore Pasteur pipette. The blood was immediately transferred to a heparinized test-tube, and the osmotic fragility of the cells tested within 5 min of collection of the blood.