[Clinical prognostic analysis of 124 adult patients with hemophagocytic lymphohistiocytosis: a multicenter retrospective study of the Huaihai Lymphoma Working Group].

Objective: Factors influencing the prognosis of hemophagocytic lymphohistiocytosis (HLH) in adults were analyzed based on multicentric data. Methods: Clinical data of 124 adult patients with HLH diagnosed in eight medical centers in the Huaihai Lymphoma Working Group from March 2014 to July 2020 were collected. The optimal truncation value of continuous variables was obtained based on the Maxstat algorithm, X-Tile software, and restricted cubic spline. Cox proportional risk regression model was used to construct the adult HLH risk prediction model, and the visualization of the model was realized through the histogram. The bootstrap resampling method was used to verify the model, C-index and calibration curve was used to verify the histogram, and the prediction accuracy was checked. Kaplan-Meier analysis was used to calculate the survival rate and draw the survival curve. Furthermore, the differences between groups were tested by log-rank. Results: The median age of the 124 patients was 55 (18-84) years, including 61 (49.19%) males. The most common etiology was infection. Serum ferritin increased in 110 cases (88.71%) , hepatosplenomegaly in 57 cases (45.97%) . Of the 124 patients, 77 (62.10%) died, and the median survival time of the patients was 7.07 months. Univariate results showed that the prognosis of adult HLH was influenced by sex, age, fibrinogen, serum creatinine, alanine aminotransferase, and albumin (P<0.05) . The results of multivariate analysis showed that gender, platelet, albumin, alanine aminotransferase, and treatment regimens were independent influencing factors for prognosis. Based on the above five risk factors, the prediction model of the histogram was established, and the C-index of the model was 0.739. Finally, the calibration chart showed good consistency between the observed and predicted values of HLH. Conclusion: The prognosis of the adult hemophagocytic syndrome is influenced by many factors. Gender, platelet, albumin, alanine aminotransferase, and treatment regimens are independent risk factors. Therefore, the established histogram provides a visual tool for clinicians to evaluate the prognosis of adult HLH.

Influence of multifrequency vibration on the optical performance of diamond-turned optics and its elimination method.

In this work, to reveal the underlying mechanism of the influence of multifrequency vibration on the optical performance of diamond-turned optics, a systematic simulation investigation is performed using Fourier modal method and fast Fourier transformation based on a well-established surface topography model. Both the simulation results and the experimental observations demonstrate that the center area is the most heavily influenced region on the machined surface, which is closely associated with the distribution of the surface roughness under multifrequency vibration. The vibration amplitude has a visible impact on the specular reflectivity, and with an increase in vibration amplitude, the specular reflectivity in the center area obviously decreases, while the specular reflectivity in remote areas basically remains invariant. To eliminate the negative effect in relation to the vibration, a two-step process technology is developed that includes a strict spindle balance and the optimization of process parameters, particularly the depth of cut and the spindle speed. The cutting experiments further validate the effectiveness of the proposed technology for elimination of the negative effect concerning multifrequency vibration.

Influence of tool edge waviness on the diffraction effect of diamond-turned optics: theoretical simulation and experimental validation.

In this work, the influence of tool edge waviness on the diffraction effect of diamond-turned optics is simulated theoretically and further validated experimentally. In simulation, a 3D surface topography model with consideration of the influence of tool edge waviness is established, in which the variation of tool edge profile is estimated by a linear model in relation to the cutting distance. The results show that the diffraction effect represented in simulation is consistent with the experimental observation. With the deterioration of tool edge waviness, the diffraction efficiency of the specular light decreases, but the high-order diffracted light intensively distributes in the horizontal direction on the receiving screen. Such observation can be attributed to the subgrating effect induced by the periodic duplication of the tool edge profile on the machined surface, which heavily depends on the deterioration of tool edge waviness. Finally, a waviness-controlled diamond tool is recommended to finish a diffraction-free optics by the diamond turning process. Moreover, the diffraction effect can also be employed to monitor the dynamic wear of the cutting tool in diamond turning.

Diffraction effect and its elimination method for diamond-turned optics.

In the visible light band, the diffraction effect of a diamond-turned surface will cause the optical performance to heavily deteriorate. Due to the insufficient understanding of diffraction effect, post-treatment, such as polishing technology has to be fulfilled. To reveal the origins of diffraction effect of the diamond-turned surface under visible light, theoretical analyses are carried out with consideration of the influencing factors in diamond turning. Simulation results, coupled with experimental observations, demonstrate that the periodic components of surface roughness are responsible for the diffraction light distribution in the horizontal direction of the receiving screen. However, the aperiodic components of surface roughness, derived from defects in material matrix, result in the diffraction spots on the whole receiving screen. To directly eliminate the diffraction effect in diamond turning, a novel method-with control on tool edge quality, material defects, and processing parameters-is proposed. The measurement results prove the effectiveness of this method, and the diffraction-free surface finish without any post-treatment is successfully acquired.

FV3-like ranavirus infection outbreak in black-spotted pond frogs (Rana nigromaculata) in China.

In April 2016, an outbreak emerged in a cultured population of black-spotted pond frog tadpoles in Shuangliu County, China, whereas tadpoles were suffering from substantial mortality (90%). Principal clinical signs of diseased tadpoles were comprised haemorrhage on their body surface, swollen abdomen with yellow ascites, congestion and swelling of the liver. The diseased tadpole's homogenates tissue were inoculated into epithelioma papulosum cyprini (EPC) cells at 25 °C for 4 days which caused typical cytopathic effect, and the viral titer TCID50 reached 107/0.1 mL. In pathogenicity tests, tadpoles were immersed in 2‰ virus fluid for 8 h, the clinical signs were observed similar to those recognized in naturally infected tadpoles and mortality rate were reached up to 80%, which affirms that the virus was the main cause for this disease. In addition, transmission electron microscopy of EPC cells infected with isolated virus reflected that the virus was in a regular hexagon way (shape) with capsule like structure. The diagonal diameter was recorded 135 ±â€¯8 nm, wherever virus particles were arrayed in crystalline manner in the cytoplasm. The electrophoresis of MCP gene PCR-product showed that the samples of diseased tadpoles, aquaculture water source and isolated virus were all positive. The sequence of the isolate revealed more than 99% similarities to ranavirus based on homology and genetic evolution analysis of the whole MCP gene, and the isolate belongs to FV3-like virus group. This study confirmed that ranavirus was the causative agent of this outbreak, and named the virus as Rana nigromaculata ranavirus (RNRV).

[Risk factors of gout in Jinchang cohort: a Cox regression analysis].

Objective: To explore the incidence and risk factors of gout in Jinchang cohort and provide scientific evidence for the prevention and control of gout. Methods: People without gout detected by baseline survey in Jinchang cohort were selected as study subjects. All the subjects were followed up through questionnaire interview, physical examination as well as laboratory test from January 24, 2013 to November 24, 2015. Cox regression model was used to analyze the risk factors for gout in Jinchang cohort. In addition, log-linear model was used to analyze the interaction between risk factors. Results: A total of 33 153 subjects were followed up, and there were 277 newly diagnosed gout cases in the cohort. The overall incidence of gout was 0.8%. The incidence of gout in males was higher than that in the females, but the incidence of gout in males and females was similar after the age of 60 years. Cox regression analysis showed that age >40 years (at age 40 to 59 years: HR=2.982, 95%CI: 1.503-5.981; at age 60 to 91 years: HR=2.588, 95%CI: 1.107-6.049), alcohol abuse (HR=2.234, 95% CI: 1.128-4.427), obesity (HR=2.204, 95% CI: 1.216-3.997), diabetes (HR=2.725, 95% CI: 1.500-4.950) and high uric acid (HR=5.963, 95%CI: 3.577-9.943) were risk factors for gout, while weekly beans intake ≥0.25 kg (HR=0.528, 95%CI: 0.345-0.808) and regular physical exercise (HR=0.499, 95% CI: 0.286-0.869) were protective factors for gout. The analysis with log-linear model showed that there were two order effects between the risk factors. Conclusions: Age, beans intake, alcohol abuse, physical exercises, obesity, diabetes and high uric acid were important factors influencing the incidence of gout. It is important to have healthy lifestyle and dietary habits, receive regular health examination to prevent and control the incidence of gout in this cohort.

Differential Dmrt1 transcripts in gonads of the protandrous black porgy, Acanthopagrus schlegeli.

Black porgy, Acanthopagrus schlegeli Bleeker, is a marine protandrous hermaphrodite fish. A Dmrt1 cDNA was cloned and characterized and in order to study the process of sex change in this species, mRNA transcripts of Dmrt1 were monitored. Dmrt1 was specifically transcribed in testis and seminal vesicle in 2-year-old black porgy according to RT-PCR and Southern analysis. A real-time quantification PCR analysis was further developed for the measurement of Dmrt1 transcripts. Dmrt1 transcripts were at significantly higher levels in bisexual testis than bisexual ovary in 1+ and 2+ year-old fish. Dmrt1 transcripts decreased in the functional and bisexual testis of 3-year-old fish. Much higher levels of Dmrt1 transcripts in the bisexual ovary were detected in 1+ year-old fish than in 2+ and 3-year-old fish. No differences in Dmrt1 transcripts were found in bisexual ovaries of 2+ and 3-year-old fish and female ovaries of 3-year-old fish. The data suggest there is relationship of Dmrt1 to the sex change of protandrous black porgy.

Pan-colonic decrease in interstitial cells of Cajal in patients with slow transit constipation.

BACKGROUND: Interstitial cells of Cajal (ICC) are required for normal intestinal motility. ICC are found throughout the human colon and are decreased in the sigmoid colon of patients with slow transit constipation. AIMS: The aims of this study were to determine the normal distribution of ICC within the human colon and to determine if ICC are decreased throughout the colon in slow transit constipation. PATIENTS: The caecum, ascending, transverse, and sigmoid colons from six patients with slow transit constipation and colonic tissue from patients with resected colon cancer were used for this study. METHODS: ICC cells were identified with a polyclonal antibody to c-Kit, serial 0.5 microm sections were obtained by confocal microscopy, and three dimensional software was employed to reconstruct the entire thickness of the colonic muscularis propria and submucosa. RESULTS: ICC were located within both the longitudinal and circular muscle layers. Two networks of ICC were identified, one in the myenteric plexus region and another, less defined network, in the submucosal border. Caecum, ascending colon, transverse colon, and sigmoid colon displayed similar ICC volumes. ICC volume was significantly lower in the slow transit constipation patients across all colonic regions. CONCLUSIONS: The data suggest that ICC distribution is relatively uniform throughout the human colon and that decreased ICC volume is pan-colonic in idiopathic slow transit constipation.

Loss of interstitial cells of cajal and inhibitory innervation in insulin-dependent diabetes.

BACKGROUND & AIMS: Gastrointestinal complications of long-standing diabetes include nausea, vomiting, abdominal pain, diarrhea, and constipation. The pathophysiology underlying these symptoms is poorly understood. Recent evidence suggests an important role for interstitial cells of Cajal in controlling gastrointestinal motility. The aim of this study was to determine changes in interstitial cells of Cajal and enteric innervation in a patient with insulin-dependent diabetes. METHODS: A full thickness jejunal biopsy was obtained from a 38-year-old insulin-dependent diabetic with evidence for diabetic gastroenteropathy. Immunohistochemistry, confocal microscopy, and 3-dimensional reconstruction techniques were used to quantify changes in the volume of interstitial cells of Cajal and enteric innervation. RESULTS: Interstitial cells of Cajal were markedly decreased throughout the entire thickness of the jejunum. A decrease in neuronal nitric oxide synthase, vasoactive intestinal peptide, PACAP, and tyrosine hydroxylase immunopositive nerve fibers was observed in circular muscle layer while substance P immunoreactivity was increased. CONCLUSIONS: The data suggest that long-standing diabetes is associated with a decrease in interstitial cells of Cajal volume and a decrease in inhibitory innervation, associated with an increase in excitatory innervation. The changes in interstitial cells of Cajal volume and enteric nerves may underlie the pathophysiology of gastrointestinal complications associated with diabetes and suggest future therapeutic targets.

Mitogen activated protein kinase plays a significant role in metaphase II arrest, spindle morphology, and maintenance of maturation promoting factor activity in bovine oocytes.

Mammalian oocytes are arrested at the G2/M transition of the first meiotic division from which, after reaching full size and subsequent to an LH surge, they undergo final maturation. Oocyte maturation, which involves germinal vesicle breakdown, progression through metaphase I (MI), and arrest at MII, is triggered and regulated by the coordinated action of two kinases, maturation promoting factor (MPF) and mitogen activated protein kinase (MAPK). The importance of the role of MPF in mammalian oocyte maturation is well established, while the role of MAPK, although well understood in mouse oocytes, has not been fully elucidated in oocytes of large domestic species, especially bovine oocytes. Here we show that injection of MKP-1 mRNA, which encodes a dual specificity MAPK phosphatase, into germinal vesicle stage bovine oocytes prevents the activation of MAPK during maturation. Despite the lack of MAPK activity, MKP-1-injected oocytes resume and progress through meiosis, although they are unable to arrest at MII stage and, by 22-26-hour post-maturation, exhibit decondensed pronucleus-like chromatin, a clear sign of parthenogenetic activation. MKP-1-injected bovine oocytes exhibit normal activation of MPF activity; however, by 18-hour post-maturation, MPF activity starts to decline and by 22-26 hr MPF activity is absent. MKP-1-injected oocytes also show disorganized MII spindles with poorly aligned chromosomes. In summary, our results demonstrate that in bovine oocytes MAPK activity is required for MII arrest, maintenance of MPF activity, and spindle organization.

A study on pathogenicity of hepatitis G virus.

AIM: To study the pathogenicity of hepatitis G virus (HGV) and observe the genesis and pathological process of hepatitis G. METHODS: HGV-RNA in serum was detected by RT-PCR assay. The immunohistochemical assays of liver tissue were performed with HGV monocoloned antibody (McAb) expressed from the region of HGV NS5 nucleic acid sequence. The clinical and pathological data of 52 patients with hepatitis G were discussed. In animal experiment, the Chinese Rhesus monkeys were infected with the serum of a patient with HGV infection. And the dynamic changes in serology and liver histology of animals were observed. RESULTS: One hundred and fifty-four patients with HGV-RNA positive were selected from 1552 patients with various kinds of hepatitis. Of 154 patients with HGV infection, 52 were infected with HGV only, which accounted for 33.8 (52/154) and 102 with positive HGV-RNA were super-infected with other hepatitis viruses, which accounted for 66.2 (102/154). The clinical and pathological observation showed that the acute and chronic hepatitis could be induced by HGV. The slight abnormality of transaminases ALT and AST in serum of monkeys lasted nearly 12 months and histological results showed a series of pathological changes. CONCLUSION: HGV is a hepatotropic virus and has pathogenicty.

Down-regulation of the inositol 1,4,5-trisphosphate receptor in mouse eggs following fertilization or parthenogenetic activation.

Fertilization in mammalian eggs is characterized by the presence of intracellular calcium ([Ca(2+)]i) oscillations. In mouse eggs, these oscillations cease after a variable period of time and this is accompanied by a decrease in inositol 1,4,5-trisphosphate receptor (IP3R) responsiveness and down-regulation of the IP3R type 1 (IP3R-1). To investigate the signaling pathway responsible for inducing IP3R-1 down-regulation during fertilization, mouse eggs were exposed to or injected with several Ca(2+)-releasing agonists and the amounts of IP3R-1 immunoreactivity evaluated by Western blotting. Exposure to ethanol or ionomycin, which induce a single [Ca(2+)]i rise, failed to signal down-regulation of IP3R-1. However, [Ca(2+)]i oscillations induced by injection of boar sperm fractions (SF), which presumably stimulate production of IP3, or adenophostin A, an IP3R agonist, both induced down-regulation of IP3R-1 of a magnitude similar to or greater than that observed after fertilization. Exposure to thimerosal, an oxidizing agent that modifies the IP3R without stimulating production of IP3, also initiated down-regulation of IP3R-1, although oscillations initiated by SrCl(2) failed to evoke down-regulation of IP3R-1. The degradation of IP3R-1 in mouse eggs appears to be mediated by the proteasome pathway because it was inhibited by preincubation with lactacystin, a very specific proteasome inhibitor. We therefore suggest that persistent stimulation of the phosphoinositide pathway in mouse eggs by the sperm during fertilization or by injection of SF leads to down-regulation of the IP3R-1.

Injection of sperm cytosolic factor into mouse metaphase II oocytes induces different developmental fates according to the frequency of [Ca(2+)](i) oscillations and oocyte age.

Intracellular calcium ([Ca(2+)](i)) rises are a hallmark of mammalian fertilization and are associated with normal activation of embryonic development. Injection of mammalian sperm cytosolic factor (SCF) into oocytes has been shown to trigger [Ca(2+)](i) rises similar to those observed during fertilization, and to initiate normal embryonic development. However, Ca(2+) release has also been shown to be associated with cell death, but the mechanisms of the detrimental effects of Ca(2+) stimulation on development have not yet been investigated. Thus, studies were undertaken using SCF to test the effects of [Ca(2+)](i) oscillations on oocyte activation in freshly ovulated and aged oocytes. Injections of 1 mg/ml SCF into freshly ovulated mouse metaphase II oocytes, which evoked Ca(2+) responses with low frequency and short duration, induced normal activation and cleavage to the two-cell stage. Conversely, injection of 15 mg/ml SCF, which triggered high-frequency and persistent Ca(2+) responses, induced abnormal activation that was characterized by abnormal chromatin configurations, inhibition of DNA synthesis, and lack of first mitotic spindle assembly. More importantly, fertilization-like Ca(2+) responses induced by injection of 1 mg/ml SCF triggered cell death, rather than activation, in in vitro-aged oocytes. These oocytes exhibited extensive cytoplasmic and DNA fragmentation that was accompanied by activation of protein caspases, all of which are signs of apoptotic cell death. Fewer similarly aged oocytes that were either unstimulated or activated with 7% ethanol underwent fragmentation. Together, these results suggest that [Ca(2+)](i) oscillations are required to activate freshly ovulated oocytes, but if initiated at abnormally high frequency and duration or if induced in aged oocytes, the [Ca(2+)](i) oscillations may trigger premature termination of embryonic development.

Decreased interstitial cell of cajal volume in patients with slow-transit constipation.

BACKGROUND & AIMS: The cause of slow-transit constipation is incompletely understood. Recent observations suggest a central role for interstitial cells of Cajal in the control of intestinal motility. The aim of this study was to determine the volume of interstitial cells of Cajal in the normal sigmoid colon and in the sigmoid colon from patients with slow transit constipation. METHODS: Sigmoid colonic samples were stained with antibodies to protein gene product 9.5, c-Kit, and alpha-smooth muscle actin. Three-dimensional reconstruction of regions of interest was performed using consecutive images collected on a laser scanning confocal microscope and ANALYZE software. RESULTS: Volume of interstitial cells of Cajal was significantly decreased in all layers of sigmoid colonic specimens from patients with slow-transit constipation compared with normal controls. Neuronal structures within the colonic circular smooth muscle layer were also decreased. CONCLUSIONS: A decrease in the volume of interstitial cells of Cajal may play an important role in the pathophysiology of slow-transit constipation.

Isoforms of the inositol 1,4,5-trisphosphate receptor are expressed in bovine oocytes and ovaries: the type-1 isoform is down-regulated by fertilization and by injection of adenophostin A.

Mammalian fertilization is characterized by the presence of long-lasting intracellular calcium ([Ca2+]i) oscillations that are required to induce oocyte activation. One of the Ca2+ channels that may mediate this Ca2+ release is the inositol 1,4, 5-trisphosphate receptor (IP(3)R). Three isoforms of the receptor have been described, but their expression in oocytes and possible roles in mammalian fertilization are not well known. Using isoform-specific antibodies against IP(3)R types 1, 2, and 3 and Western analysis, we determined the isoforms that are expressed in bovine metaphase II oocytes and ovaries. In oocytes, all isoforms are expressed, but type 1 is present in overwhelmingly larger amounts and is likely responsible for the majority of Ca2+ release at fertilization. In ovarian microsomes, all three isoforms appear well expressed, suggesting the participation of all IP(3)R isoforms in ovarian Ca2+ signaling. We then investigated whether the reported cessation/reduction in amplitude of fertilization-associated [Ca2+]i oscillations, which is observed as pronuclear formation approaches, corresponded with down-regulation of the IP(3)R-1 isoform. Fertilization resulted in approximately 40% reduction in the amount of receptor by 16 h postinsemination. In addition, injection of adenophostin A, a potent IP(3)R agonist that elicits high-frequency [Ca2+]i oscillations in mammalian oocytes, induced similar reduction in receptor numbers. Together, these data show that 1) the three IP(3)R isoforms are expressed in bovine oocytes; 2) IP(3)R-1 is likely to mediate most of the Ca2+ release during fertilization; 3) its down-regulation may explain the decline in amplitude of sperm-induced [Ca2+]i rises as fertilization progresses toward pronuclear formation; and 4) agonists of the IP(3)R induce down-regulation of the type-1 receptor in oocytes similar to that evoked by fertilization.

Partial characterization of the calcium-releasing activity of porcine sperm cytosolic extracts.

Injection of sperm cytosolic extracts into mammalian eggs has been shown to elicit intracellular calcium ([Ca2+]i) oscillations that are similar in amplitude, duration, and frequency to those observed following fertilization. Thus, to characterize the Ca2+-release component(s) in porcine sperm cytosolic extracts, a combination of fractionation techniques was used. The fraction with Ca2+ releasing activity was precipitated by 50% saturating solutions of ammonium sulfate and Western blot analysis showed that the pellets contained glucosamine-6-phosphate deaminase (gpd)/oscillin, a protein which has been suggested to be the sperm's active component. Single and double isoelectrofocusing (IEF) of porcine sperm extracts generated fractions with different Ca2+-releasing activities. Fractions with maximal Ca2+-releasing activity did not contain material that was immunoreactive with antibodies against gpd/oscillin; adjacent fractions containing gpd/oscillin had no Ca2+-releasing activity. These findings were confirmed by IEF coupled with size exclusion chromatography on Superose 12 and with hydroxyapatite chromatography. These procedures predict an isoelectric point of our active component of 6.5-7.0 and a relative molecular weight ranging from 29 to 68 kDa. In summary, the data show that the Ca2+ release-inducing component(s) of porcine sperm extracts can be fractionated and that gpd/oscillin is not the pig sperm Ca2+ oscillogen.

Injection of a porcine sperm factor induces activation of mouse eggs.

Injection of sperm preparations into mammalian oocytes and eggs has been shown to elicit persistent [Ca2+]i oscillations that closely resemble fertilization-associated Ca2+ release. However, the ability of these sperm fractions to initiate egg activation has not been clearly demonstrated. In the present experiments, mouse eggs injected with a porcine sperm preparation were evaluated for early and late events of activation. Events monitored included, among early events, the generation of [Ca2+]i oscillations and cortical granule exocytosis and, among late events, the decrease in histone H1 and myelin basic protein kinase activities, polar body extrusion, pronuclear formation, and cleavage to the two-cell stage. Injection of sperm fractions consistently evoked [Ca2+]i oscillations that, in turn, initiated all events of activation. Uninjected control eggs or eggs injected with buffer or heat-treated sperm fractions failed to show Ca2+ responses or activation. In addition, injection of sperm fractions into recently ovulated eggs (experiments were concluded within 15 hr after human chorionic gonadotropin administration) induced high rates of activation, while similarly aged eggs exposed to 7% ethanol for 5 min, a known parthenogenetic treatment, failed to activate. Together these results indicate that injection of sperm fractions elicits [Ca2+]i oscillations that are capable of initiating normal egg activation. These results support the hypothesis that a sperm component participates in the generation of fertilization-associated [Ca2+]i oscillations.

Calcium, calcium release receptors, and meiotic resumption in bovine oocytes.

During maturation, mammalian oocytes undergo a series of changes that prepare them for fertilization. These events are regulated by kinases, most notably histone H1 and mitogen-activated protein kinase. Intracellular calcium ([Ca2+]i) oscillations participate in oocyte signaling, and it has been postulated that they play a role in oocyte maturation. In these studies we investigated the association of Ca2+, Ca2+ channels, and activation of kinases in in vitro-maturating bovine oocytes. BAPTA-AM, a Ca2+ chelator, inhibited oocyte maturation and delayed activation of kinases, although spontaneous [Ca2+]i rises were not observed in control oocytes loaded with fura-2, a Ca2+ indicator. The ability of the 1,4,5-inositol trisphosphate receptor (InsP3R) to release Ca2+, monitored after the addition of thimerosal and myo-inositol 1,4,5-trisphosphate (InsP3), increased as maturation progressed. This may be associated with a similar increase, monitored by Western blotting, in the density of the type I InsP3R isoform during oocyte maturation. Injection of heparin, an InsP3R antagonist, blocked oocyte maturation and activation of kinases. The density of the ryanodine receptor, another Ca2+ channel, may be 30- to 100-fold lower than that of the InsP3R in bovine oocytes. Thus, our results demonstrate that [Ca2+]i participates in the progression of meiosis and that the InsP3R may be responsible for the majority of Ca2+ release during maturation and fertilization.

Injection of a porcine sperm factor triggers calcium oscillations in mouse oocytes and bovine eggs.

Fertilization in mammals is associated with the generation of intracellular calcium ([Ca2+]i) oscillations. The site of, or mechanism(s) utilized by, the sperm to initiate and maintain these Ca2+ responses is not known. In this study, we tested the hypothesis that a factor from the sperm is capable, upon release into the oocyte's cytosol, of initiating oscillations. A sperm factor, prepared from porcine semen, was injected into mouse oocytes and bovine eggs that had been loaded with fura-2 dextran, a fluorescent Ca2+ indicator. The resulting Ca2+ responses were monitored and compared to those characteristic of each species. Our results show that injection of sperm factor triggered long-lasting [Ca2+]i oscillations, and that the observed patterns were species-specific. In mouse oocytes, sperm factor-induced [Ca2+]i rises exhibited high frequency, whereas in bovine eggs, Ca2+ responses were separated by long intervals. Further characterization of the sperm factor revealed that it was predominantly present in sperm preparations, that it contained a protein moiety, and that it was unlikely to be a protease. The intracellular Ca2+ channels/receptors through which the sperm factor-mediated Ca2+ release was investigated by using heparin, a competitive inhibitor of the inositol 1,4,5 trisphosphate receptor (InsP3R), and ryanodine, which binds the ryanodine receptor (RyR). The sperm factor appeared to stimulate InsP3R, at least in mouse oocytes, because sperm factor-induced oscillations were delayed or blocked in all oocytes by injection of heparin. RyR may be involved in the modulation of these oscillations, since addition of ryanodine modified Ca2+ responses to the sperm factor. The present results support the hypothesis that a factor from the sperm is involved in the generation of fertilization-associated [Ca2+]i oscillations.