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PubMed1997

Methods for the determination of nitrite by high-performance liquid chromatography with electrochemical detection.

A review on the use of high-performance liquid chromatography coupled with electrochemical detection (HPLC-ED) for the measurement of nitrite (NO2-) and nitrate (NO3-) is presented. HPLC-ED has been used for the determination of NO2- and NO3- in food, biological and environmental samples. Analysis of the current literature indicates that the measurement of NO2- and NO3- by the HPLC-ED procedure is more sensitive, selective and faster than methods based on UV absorption, photometry, fluorometry or chemiluminescence.

Chromatography, High Pressure Liquid↗
PubMed1998

Analysis of macrolide antibiotics.

The following macrolide antibiotics have been covered in this review: erythromycin and its related substances, azithromycin, clarithromycin, dirithromycin, roxithromycin, flurithromycin, josamycin, rokitamycin, kitasamycin, mycinamycin, mirosamycin, oleandomycin, rosaramicin, spiramycin and tylosin. The application of various thin-layer chromatography, paper chromatography, gas chromatography, high-performance liquid chromatography and capillary zone electrophoresis procedures for their analysis are described. These techniques have been applied to the separation and quantitative analysis of the macrolides in fermentation media, purity assessment of raw materials, assay of pharmaceutical dosage forms and the measurement of clinically useful macrolide antibiotics in biological samples such as blood, plasma, serum, urine and tissues. Data relating to the chromatographic behaviour of some macrolide antibiotics as well as the various detection methods used, such as bioautography, UV spectrophotometry, fluorometry, electrochemical detection, chemiluminescence and mass spectrometry techniques are also included.

Animals↗
PubMed2002

Quantitation of natural killer cell precursors in man.

A technique was developed to measure the frequency of natural killer cell precursors (NKpf) in human peripheral blood mononuclear cell (PBMC) samples. Functional maturity of NK cells was reflected in their ability to lyse target cells from the K562 cell line. During the development of the technique, venous blood was taken from one healthy adult and assayed at different times to avoid individual variation. The technique was based on the principle of limiting dilution analysis. The NKpf assay was set up with a range of cell dilutions from 40,000 to 625 per 100 microl/well in 96-well culture plates. At the end of the culture period, the K562 cell line labelled with europium (Eu-K562) was added and the Eu-release was measured in culture supernatants using time-resolved fluorometry. The NKpf value differed between individuals and was influenced by the length of time in culture, being maximal at day 5. Maturation of NKp required the continuous presence of recombinant interleukin 2 (rIL-2), or rIL-15, both being equally effective. In the absence of cytokines, the functional NK cells declined rapidly beyond 24 h in culture. Irradiated allogeneic cells appeared to substitute in part for cytokines, but the numbers of allo-activated NKpf were lower than those observed when allo-activated NKpf were cultured with rIL-2. This suggested selective activation by the allogeneic stimulus of subsets of NKp or rIL-2-rescue of NKp subsets destined for apoptotic cell death. Alternatively, the increased frequency could have been attributable to activation of precursors of natural killer-T cells (NK-Tp). This assay is suitable for estimating the total number of precursors of functional NK cells in the blood of patients.

Aged↗
PubMed1997

Dual-label time-resolved immunofluorometric assay for simultaneous determination of pregnancy-associated plasma protein A and free beta-subunit of human chorionic gonadotrophin.

Using time-resolved fluorometry, a simple one-step dual-label immunometric assay has been developed, which allows simultaneous determination of pregnancy-associated plasma protein A (PAPP-A) and free beta-subunit of human chorionic gonadotrophin (beta-hCG) in first-trimester maternal serum samples. Two monoclonal antibodies were biotinylated and immobilized onto the surface of streptavidin-coated microtitration plates, and used to capture PAPP-A and beta-hCG. respectively. Europium (Eu) and Samarium (Sm) chelates were conjugated to two additional monoclonal antibodies acting as detection antibodies for PAPP-A and beta-hCG. The assay was performed using a 4-h one-step format. The within-run precision with buffer-based calibrators was below 8% over the working range of PAPP-A (40-10000 mIU/l) and beta-hCG (7.3-525 micrograms/l) and no hook effect was observed. The intra- and inter-assay coefficients of variation were below 7.1% for serum samples. PAPP-A and beta-hCG concentrations measured by the dual assay in 39 first-trimester serum samples correlated excellently with those obtained by DELFIA single-label PAPP-A (r = 0.997) and the beta-hCG part (r = 0.993) of the DELFIA AFP/beta hCG dual-label assay.

Antibodies, Monoclonal↗
PubMed2003

Integrin alphaIIbbeta3 and shear-dependent action of glycoprotein Ibalpha stimulate platelet-dependent thrombin formation in stirred plasma.

Under conditions of arterial-wall shear rates, platelets bind to von Willebrand factor (vWf) by way of the glycoprotein Ib (GP Ib) complex and integrin alpha(IIb)beta(3). Both adhesive receptors may also play roles in the development of procoagulant activity of platelets. Here, we investigated the effect of shear stress, as provided by a rotating cylinder, on GP Ib- and integrin alpha(IIb)beta(3)-dependent thrombin generation in coagulating platelet-rich plasma (PRP). We measured thrombin continuously with the use of fluorometry from the cleavage rate of a fluorescent low-affinity substrate. The integrin alpha(IIb)beta(3) antagonist abciximab progressively reduced the peak of thrombin formation up to 43% when rate of stirring and shear stress were increased (estimated shear rates of 105-420 s(-1)). Abciximab did not lower the peak of thrombin formation in stirred PRP from patients with Glanzmann's thrombasthenia lacking alpha(IIb)beta(3) but, surprisingly, shortened the time until onset. In PRP from control subjects, antibodies specifically directed against vWf-binding epitopes on GP Ibalpha reduced thrombin formation, with 25% to 30% at the high but not at the low stirring rate. In combination with the anti-GP Ib antibody, abciximab retained its strong inhibitory effect only at the high stirring rate. We conclude that thrombin formation and coagulation in stirred PRP depend, to a large extent, on platelet adhesion to integrin alpha(IIb)beta(3) and, in a shear-dependent way, on GP Ib.

Blood Coagulation↗
PubMed1988

Diabetes-induced changes of proteins synthesized by adult cardiac myocytes are partially reversed by insulin.

In the rat heart diabetes mellitus leads to a change in myosin heavy chain (MHC) mRNAs and corresponding alterations in myosin isoenzymes as well as a decrease in total cardiac protein synthesis. However, it is still unknown whether cardiac proteins other than MHC are altered by diabetes and if so whether these abnormalities are mediated by insulin deficiency. To answer these questions we analyzed proteins synthesized by isolated cardiac myocytes in the presence or absence of insulin. Enzymatically dispersed adult cardiac myocytes from control and streptozotocin-induced diabetic rats were incubated in medium containing [35S]-methionine for 4 h; diabetic cells were incubated with or without the addition of 5 x 10(-7)M insulin. The labelled peptides were then separated by two-dimensional polyacrylamide gel electrophoresis and analyzed by fluorometry. The abundance of six individual polypeptides was consistently affected by diabetes: one protein was significantly decreased while four others were increased in diabetic myocytes. The remaining protein showed a shift in isoelectric point without a change in molecular weight possibly representing isoforms of a single polypeptide. The addition of insulin reverted the predominance of three proteins back to normal while it did not affect the other three at all. In conclusion diabetes induces changes in the abundance of a few proteins synthesized in vitro by cardiac myocytes and only half of them show an acute response to insulin.

Animals↗
PubMed2003

Lysyl-tRNA synthetase from Bacillus stearothermophilus: the Trp314 residue is shielded in a non-polar environment and is responsible for the fluorescence changes observed in the amino acid activation reaction.

Three Trp variants of lysyl-tRNA synthetase from Bacillus stearothermophilus, in which either one or both of the two Trp residues within the enzyme (Trp314 and Trp332) were substituted by a Phe residue, were produced by site-directed mutagenesis without appreciable loss of catalytic activity. The following two phenomena were observed with W332F and with the wild-type enzyme, but not with W314F: (1) the addition of L-lysine alone decreased the protein fluorescence of the enzyme, but the addition of ATP alone did not; (2) the subsequent addition of ATP after the addition of excess L-lysine restored the fluorescence to its original level. Fluorometry under various conditions and UV-absorption spectroscopy revealed that Trp314, which was about 20A away from the lysine binding site and was shielded in a non-polar environment, was solely responsible for the fluorescence changes of the enzyme in the L-lysine activation reaction. Furthermore, the microenvironmental conditions around the residue were made more polar upon the binding of L-lysine, though its contact with the solvent was still restricted. It was suggested that Trp314 was located in a less polar environment than was Trp332, after comparison of the wavelengths at the peaks of fluorescence emission and of the relative fluorescence quantum yields. Trp332 was thought, based on the fluorescence quenching by some perturbants and the chemical modification with N-bromosuccinimide, to be on the surface of the enzyme, whereas Trp314 was buried inside. The UV absorption difference spectra induced by the L-lysine binding indicated that the state of Trp314, including its electrostatic environment, changed during the process, but Trp332 did not change. The increased fluorescence from Trp314 at acidic pH compared with that at neutral pH suggests that carboxylate(s) are in close proximity to the Trp314 residue.

Amino Acid Substitution↗
PubMed2001

Human gastrinoma cells express calcium-sensing receptor.

The intravenous calcium injection test has been reported to be useful for the diagnosis of gastrinoma. However, the mechanism underlying calcium-evoked gastrin release is not fully understood. We investigated the mechanism of calcium-stimulated gastrin release from gastrinoma cells in vitro with a particular focus on the calcium-sensing receptor (CaR). Human gastrinoma cells were taken from mechanically minced gastrinoma tissues obtained at surgery. In the perifusion system, high [Ca2+]o induced gastrin release from gastrinoma cells. As [Ca2+]o increased, [Ca2+]i rapidly increased, as monitored by fluorometry. The response was not inhibited by nifedipine, a blocker of the voltage-dependent calcium channel. Reverse transcriptase-polymerase chain reaction and subsequent Southern blot hybridization revealed the presence of the CaR gene in human gastrinoma tissues. Moreover, the expression of CaR in gastrinoma tissues was confirmed by immunohistochemistry. Our results demonstrated that CaR was expressed in human gastrinoma cells and could be involved in the mechanism of calcium-evoked gastrin release.

Blotting, Southern↗
PubMed2002

Functional muscarinic M2 and M3 receptors and beta-adrenoceptor in cultured rat bladder smooth muscle.

A highly purified rat urinary bladder smooth muscle cell culture was obtained by a modified enzymic isolation method, and the presence of functional muscarinic as well as beta-adrenergic receptors were subsequently determined. At 7-10 days of culture, cells became elongated and spindle-shaped showing a typical "hills and valleys" form. They were stained with anti-alpha-actin and anti-myosin antibodies. Radiolabeled ligand binding using [3H]N-methylscopolamine and [3H]CGP12177 showed that these cells expressed muscarinic and beta-adrenergic receptors. Stimulation of cultured cells with carbachol inhibited the forskolin-stimulated cyclic AMP formation, caused an elevation of intracellular Ca2+ concentration measured by fura-2 fluorometry. The latter response was almost completely blocked by 4-DAMP, a selective muscarinic M3 antagonist. On the other hand, stimulation of cultured cells with isoproterenol enhanced the basal cyclic AMP formation, which was reversed by carbachol. Therefore, the presence of functional muscarinic (both M2 and M3) as well as beta-adrenergic receptors was confirmed in pure culture of the rat bladder smooth muscle cells obtained by using an enzymic isolation method.

Adenylyl Cyclases↗
PubMed2002

Aggravation of nonsteroidal antiinflammatory drug gastropathy by glucocorticoid deficiency or blockade of glucocorticoid receptors in rats.

Our previous investigations suggest that the reduction of stress-induced corticosterone release, or inhibition of corticosterone actions, promotes stress-induced gastric erosions in rats. In this study the effect of glucocorticoid deficiency on susceptibility to gastric mucosal injury by nonsteroidal antiinflammatory drugs (NSAIDs) was evaluated in rats. Gastric erosions induced in male rats by indomethacin (25 mg/kg sc) or acidified aspirin (40 mM po) were studied one week after adrenalectomy with or without corticosterone replacement or after occupation of glucocorticoid receptors by the antagonist RU-38486 during the period of erosion formation. Corticosterone for replacement (4 mg/kg sc) was injected 15 min before the administration of indomethacin or acidified aspirin to adrenalectomized rats. The antagonist RU-38486 (10 mg/kg po) was administered twice, 20 min before and 60 min after NSAID administration. Plasma corticosterone levels were measured by fluorometry. Gastric erosions were quantitated by measuring the area of damage. Indomethacin or acidified aspirin induced both plasma corticosterone rise and gastric erosions. Adrenalectomy decreased both basal and NSAID-induced corticosterone levels and markedly promoted gastric erosion formation caused by the NSAID. An acute corticosterone replacement mimicking indomethacin-and aspirin-induced corticosterone rise prevented the effect of adrenalectomy on the gastric erosions. The administration of the glucocorticoid/progesterone antagonist RU-38486 significantly potentiated the formation of gastric erosions induced by indomethacin as well as aspirin. These observations suggest a gastroprotective action of glucocorticoids released in response to NSAID treatment against NSAID-induced injury.

Adrenalectomy↗
PubMed1997

Calcium-induced activation of the rat vascular myocyte Na+/H+ exchanger isoform-1.

An established intermediate phenotype of human hypertension and diabetic nephropathy is an elevation of Na+/H+ exchanger (NHE) activity, but the mechanism for this is unclear. This phenotype is maintained in vascular myocytes from the spontaneously hypertensive rat (SHR) compared with the normotensive Wistar Kyoto rat (WKY). Since intracellular calcium levels ([Ca2+]i) following agonist stimulation were elevated in cells from both hypertensive humans and SHR, we have examined the role of calcium-calmodulin (CaM) in the mechanism of increased NHE activity in vascular myocytes of SHR by determining the activity and phosphorylation state of NHE isoform-1 (NHE-1) in cells from SHR and WKY when [Ca2+]i was elevated by the ionophores A23187 or ionomycin. NHE activity was measured using fluorometry and NHE-1 phosphorylation by immunoprecipitating the exchanger from 32P-orthophosphate-labeled cells with a polyclonal NHE-1-specific antibody. The ionophore A23187 increased [Ca2+]i in both cell types to approximately 700 to 800 nmol x L(-1), and led to stimulation of NHE-1 activity only in WKY myocytes, with no effect on SHR cells. An inhibitor of CaM kinase II (KN-62) failed to abolish stimulation of NHE-1 by A23187 in WKY cells, and had no effect on unstimulated NHE-1 activity in both cell types. Ionomycin also elevated [Ca2+]i in both cell types to approximately 1,000 nmol x L(-1) and activated NHE-1 activity in only WKY cells. Activation of NHE-1 in WKY cells by an increased [Ca2+]i was not mediated by an increase in NHE-1 phosphorylation, whether in the presence or absence of KN-62. The elevated NHE-1 phosphorylation in SHR cells was not affected by elevated [Ca2+]i or KN-62. Calmodulin-agarose beads bound NHE-1 extracted from SHR cells to a lesser extent than that from WKY cells. We conclude that calcium-induced NHE-1 activation in WKY cells was not mediated by CaM kinase II. The elevated NHE-1 activity and phosphorylation of SHR cells was not further modulated by increased [Ca2+]i, and was also independent of CaM kinase II. Non-phosphorylation-dependent mechanisms of activation of NHE-1 may therefore be responsible for alterations of NHE-1 activity in these cells, such as the direct binding of CaM to NHE-1. This direct binding of CaM to NHE-1 may be impaired in SHR compared with WKY cells.

Animals↗
PubMed1997

Calcium-evoked insulin release from insulinoma cells is mediated via calcium-sensing receptor.

BACKGROUND: We have previously reported that high extracellular calcium ([Ca2+]o) levels elicited rapid increases in the cytosolic free calcium ([Ca2+]i) and insulin release from human insulinoma cells. In this study we further investigated the mechanism for stimulus-secretion coupling of insulinoma cells exposed to high levels of [Ca2+]o. METHODS: Insulinoma tissues were surgically obtained for primary culture. The changes of [Ca2+]i level in response to various agents were monitored by fluorometry. Total RNA was extracted from tissues and subjected to reverse transcription-polymerase chain reaction (RT-PCR) with calcium-sensing receptor (CaR)-specific primers. PCR products were subcloned and sequenced. RESULTS: When [Ca2+]o level was elevated, [Ca2+]i in insulinoma cells was immediately increased. Application of neomycin abolished the increase in [Ca2+]i level, although extracellular nifedipine and lanthanum chloride did not affect it. The depletion of intracellular calcium stores with thapsigargin or carbachol eliminated the increase in [Ca2+]i level. RT-PCR analysis identified the 682 bp product, of which the sequence was identical to the corresponding regions of human parathyroid CaR. CONCLUSIONS: Intracellular Ca2+ release might be important in insulin release from insulinoma cells after exposing to high level of [Ca2+]o. CaR could be involved in this mechanism.

Adult↗
PubMed1992

Operative assessment of intestinal viability.

Acute intestinal ischemia and infarction remain serious clinical problems despite early operative intervention. Accurate intraoperative assessment of intestinal viability is essential in determining the limits of resection in patients with intestinal infarction. Clinical features of bowel viability such as color and peristalsis do not correlate uniformly with bowel survival, and as a result, several techniques have been developed to assess intestinal blood flow at the time of operation. The requirements of an ideal viability test are: 1. The technique must have ready availability, preferably in every operating theater dealing with abdominal emergencies. 2. The necessary equipment must not be cumbersome or require specialized personnel. 3. The method must be accurate with a minimum of false-negative results and, more importantly, few false positives. A false-negative results leaves in situ nonviable bowel, which may lead to early perforation and late stricturing. This situation may be recoverable with further surgical intervention, however. On the other hand, a false-positive assessment of bowel viability results in the resection of potentially recoverable intestine, which is lost forever and may represent a vital difference for morbidity-mortality and long-term nutrition. 4. The technique must be objective and be reproducible. 5. The method must be cost effective. To date, only two tests have found widespread acceptance and clinical applicability: fluorescein assessment and Doppler studies either with ultrasound or as refined in laser velocimetry. Although other techniques may be of some value today or in the future, the most practical approach would appear to be to use fluorescein assessment under a modified Wood's lamp as the initial method of evaluating intestinal viability and either Doppler ultrasound or perfusion fluorometry for any areas of particularly doubtful viability.

Animals↗
PubMed1997

Fluorescein angiographic evaluation of the effect of latanoprost treatment on blood-retinal barrier integrity: a review of studies conducted on pseudophakic glaucoma patients and on phakic and aphakic monkeys.

Endogenous prostaglandins (PGs) have been claimed to play a role in the development of cystoid macular edema (CME). Two fluorescein angiographic studies evaluating the effect of latanoprost, a new ocular hypotensive PG analogue, on blood-retinal barrier integrity are, therefore, reviewed here. In the first study, six of eight unilaterally aphakic cynomolgus monkeys were treated bilaterally once daily for six months with 0.035% latanoprost (seven times the clinically used oculohypotensive concentration). Two of the animals served as controls. Fluorescein angiography of the fundus after one, three and six months of treatment revealed no leakage of fluorescein in any of the 16 eyes. In another study, pseudophakic eyes of 16 glaucoma patients who received twice-daily treatment with 0.006% latanoprost for four weeks were compared to eight patients treated with placebo. Biomicroscopic examination did not reveal any signs of CME and only one placebo-treated eye revealed a slight perifoveal leakage of fluorescein. These studies suggest that topically-applied latanoprost does not have a fluorescein angiographically detectable direct effect on the integrity of the blood-retinal barrier system in phakic or aphakic monkey eyes or in pseudophakic human eyes. This does not rule out the occurrence of CME in eyes more susceptible to CME, due to vitreous loss, posterior capsulotomy, or other postoperative situations. Especially in those eyes a study with latanoprost is proposed. Since, fluorescein angiography is a rather crude method of detecting abnormalities of the blood-retinal barriers, vitreous fluorometry in addition is suggested.

Animals↗
PubMed2001

A time-resolved fluoroimmunometric assay for the detection of microcystins, cyanobacterial peptide hepatotoxins.

An immunoassay based on the time-resolved fluorometry (TR-FIA) was developed for microcystins, cyanobacterial peptide hepatotoxins. The assay was performed in a competitive mode and it utilised the monoclonal antibodies raised against microcystin-LR, and a europium chelate of microcystin-LR as a competitive antigen. The sensitivity of the assay was 0.1microg/l. The detection method of TR-FIA was compared to a commercially available kit based on the enzyme-linked immunosorbent assay (ELISA). The same level of sensitivity could be obtained with TR-FIA (in a non-optimised system). The simplified method of TR-FIA leads to a shorter analysis time.

Antibodies, Monoclonal↗
PubMed2001

Potentiation of cytotoxicity of adriamycin on human ovarian carcinoma cell line 3AO by low-level ultrasound.

The aim of this study was to determine whether the ultrasound, with a dosage that did not lead to acute and delayed inhibition, could potentiate the cytotoxicity of adriamycin to human ovarian carcinoma cell line 3AO in vitro. Drug sensitivity was analyzed by clonogenic assay, cells were treated by adriamycin singly in group ADM (control), adriamycin prior to ultrasound exposure in group ADM + US, and ultrasound irradiation prior to adriamycin administration in group US + ADM. The intracellular drug accumulation in each group was determined by fluorometry. The results were: (1) the values of IC50 were 0.0083, <0.001 and 0.0065 microg/ml in group ADM, ADM + US and US + ADM respectively; the clone surviving rate in group ADM + US and in group US + ADM were decreased (P < 0.001, P < 0.01), compared with control; the surviving rate in group ADM + US was lower than that in group US + ADM (P < 0.01). (2) The intracellular drug accumulations in group ADM + US were promoted (P < 0.01) and not increased significantly in group US + ADM (P > 0.05). These suggested that the low-level ultrasound could enhance the cytotoxicity of adriamycin to human ovarian carcinoma cells and promoted intracellular drug contents played the leading role.

Antineoplastic Agents↗
PubMed2003

Apoptotic pathways of epothilone BMS 310705.

OBJECTIVE: BMS 310705 is a novel water-soluble analog of epothilone B currently in phase I clinical evaluation in the treatment of malignancies such as ovarian, renal, bladder, and lung carcinoma. Using an early passage cell culture model derived from the ascites of a patient clinically refractory to platinum/paclitaxel therapy, we evaluated the pathway of caspase-mediated apoptosis. METHODS: Cells were treated for 1 h and subsequently evaluated for apoptosis, survival, and caspase activity. Apoptosis was determined by fluorescent microscopy. Caspase-3, -8, and -9 activities were determined by fluorometry using target tetrapeptide substrates. Mitochondrial release of cytochrome c was determined by immunoblot analysis. RESULTS: After treatment with BMS 310705, apoptosis was confirmed in >25% of cells at 24 h. Survival was significantly lower (P < 0.02) in cells treated with 0.05 micro M BMS 310705 vs paclitaxel. Analysis revealed an increase of caspase-9 and -3 activity; no caspase -8 activity was observed. Release of cytochrome c was detected at 12 h following treatment. SN-38 and topotecan failed to induce apoptosis. CONCLUSIONS: BMS 310705 induces significant apoptosis, decreases survival, and utilizes the mitochondrial-mediated pathway for apoptosis in this model.

Antineoplastic Agents↗
PubMed2003

Subtle membrane changes in cryopreserved bull semen in relation with sperm viability, chromatin structure, and field fertility.

This study investigated the use of annexin-V/PI assay to assess sub lethal changes in bull spermatozoa post-thawing, and to further relate these changes to results obtained by fluorometric assessment of sperm viability and sperm chromatin structure assay (SCSA), as well as field fertility (as 56-day non-return rates, 56-day NRR) after AI. Frozen-thawed semen samples were obtained from 18 Swedish Red and White bulls (one to three semen batches/bull) and fertility data was based on 6900 inseminations. The annexin-V/PI assay revealed that post-thaw semen samples contained on average 41.8+/-7.5% annexin-V-positive cells. Most of the annexin-V-positive cells were dying cells, i.e. also PI-positive. The incidence of annexin-V-positive cells was negatively related (r=-0.59, P<0.01) to the percentage of viable cells, as detected by fluorometry. The incidence of annexin-V-positive spermatozoa significantly correlated to the SCSA variable xalphat (r=0.53, P<0.05). The incidence of annexin-V-negative, dead cells was the only annexin-V/PI assay variable that correlated significantly with fertility both at batch (r=-0.40, P<0.05), and bull (r=-0.56, P<0.05) levels. Among sperm viability variables, subjectively assessed sperm motility (r=0.52-0.59, P<0.01), CASA-assessed sperm motility (r=0.43-0.61, P<0.05), and the incidence of live spermatozoa, expressed as total numbers (r=0.39-0.54, P<0.05), or percentage values (r=0.68-0.68, P<0.01), correlated significantly with field fertility both at batch, and bull levels. Among the SCSA variables, only the COMP alphat correlated significantly (r=0.33-0.51, P<0.05) with fertility results. The results indicate a certain proportion of bull spermatozoa express PS on their surface after thawing, e.g. they have altered membrane function, and that the incidence of such cells is inversely correlated to sperm viability, and positively correlated to abnormal sperm chromatin condensation since they eventually undergo necrosis.

Animals↗