A novel variant in PAX6 as the cause of aniridia in a Chinese family

Background

Aniridia is a kind of congenital human pan-ocular anomaly, which is related to PAX6 commonly.

Methods

The ophthalmic examinations including visual acuity, slit lamp and fundoscopy examination were performed in a Chinese aniridia pedigree. The targeted next-generation sequencing of aniridia genes was used to identify the causative mutation.

Results

A novel heterozygous PAX6 nonsense mutation c.619A > T (p.K207*) was identified in the Chinese autosomal dominant family with aniridia. Phenotype related to the novel mutation included nystagmus, keratopathy, absence of iris, cataract and foveal hypoplasia.

Conclusions

The novel nonsense variation in PAX6 was the cause of aniridia in this family, which expanded the spectrum of the PAX6 mutation.

[Analysis of occupational health status of radiation workers in Guangdong Province]

Objective: To discuss the effect of low-dose ionizing radiation on the health of radiation workers, and provide a basis for occupational health risk assessment of radiation workers. Methods: In January 2020, 3165 radiation workers who performed radiation occupational health examinations in Guangzhou Prevention and Treatment Hospital for Occupational Disease from January 2017 to December 2019 were selected as the research objects, and compared and analyzed the health status of radiation workers with different examination types (pre-job, in-job and off-job) , types of work, gender, and length of service. Results: The off-job occupational radiological health examination was rare at 2.3% (74/3165) . The abnormal detection rate of chest radiographs, renal function, thyroid function, and blood routine of the radiation workers in-job group was higher than that of the pre-job group (P<0.05) . No statistical difference was found in the abnormal detection rate of the examination items during the in-job group and the off-job group (P>0.05) . The blood routine abnormality detection rate of medical application group and industrial application group were higher than those of nuclear fuel group (P<0.05) . The abnormal detection rate of blood pressure and renal function of male radiation workers was higher than that of females, while the abnormal detection rate of blood routine of females was higher than that of males (P<0.05) . The abnormal detection rate of electrocardiogram, chest radiograph, blood pressure, renal function, thyroid function, and blood routine of radiation workers increased with increasing working age (P<0.05) . Conclusion: Occupational health status of radiation workers is not optimistic. Radiation occupational health monitoring should be strengthened, special attention should be paid to off-job radiation occupational health examination, focusing on the sensitive indicators of sensitive personnel, improving radiation protection conditions, and effectively protecting the occupational health of radiation workers.

[Effect of low dose ionizing radiation on peripheral blood cells of radiation workers in nuclear power industry]

Objective: To investigate the effects of long-term ionizing radiation on peripheral blood cells of nuclear power workers. Methods: In March 2019, a total of 530 radiation exposed workers in the nuclear power industry who underwent in-service radiation occupational health examination in Guangzhou occupational disease prevention and control hospital in 2018 and with service age ≥1 year were selected as the radiation group. At the same time, 545 workers in nuclear power industry were selected as control group. According to the methods and requirements of GBZ 235-2011 ＂technical specification for occupational health monitoring of radiation workers＂ and GBZ 98-2017 ＂health requirements for radiation workers＂, the occupational health monitoring data were collected, and the change rules of peripheral blood cells in the two groups were analyzed. Results: Compared with the control group, the total number of WBC, NEUT, LYMP, Hb, MCV and MCHC in radiation group were lower than those in control group (P<0.05) , and the difference was statistically significant (P<0.05) . The MPV increased significantly (P<0.05) . Compared with the control group, the abnormal rate of WBC and Hb in the radiation group was higher than that in the control group (P<0.01) , but there was no significant difference in the abnormal rate of RBC and PLT (P>0.05) . Conclusion: Low dose ionizing radiation has a certain cumulative damage effect on peripheral blood cells of radiation workers in nuclear power industry. The change rules of different cell subtypes are different, and the changes of WBC and PLT appear earlier.

The role of transcription factor caudal-related homeobox transcription factor 2 in colorectal cancer

Colorectal cancer (CRC) is one of the most malignant tumors in humans and causes mass mortality. In the age of precise medicine, more and more subtypes of CRC were classified. The caudal-related homeobox transcription factor 2 (CDX2) is an intestine-specific transcription factor which is implicated in differentiation, proliferation, cell-adhesion, and migration. The loss of CDX2 in immunohistochemical stain was reported to be a prognostic factor of colon cancer, but the clinical application remained controversial. Most of the CRCs expressed or over-expressed CDX2. Homeobox genes can display either an oncogenic or a tumor-suppressing activity. CDX2 regulates the developing intestinal epithelium and CRC by different pathways. The complex regulation of CDX2 and its complex targets cause the difficulties of application for CDX2 in the prediction of prognosis. However, CDX2 is a potential biomarker applied in the precise classification of CRC for personalized medicine. This review partially clarifies the role of CDX2 in CRC.

[Risk factors associated with systemic inflammatory response syndrome after flexible ueteroscopic lithotripsy based on enhanced recovery after surgery]

Objective: To investigate the risk factors of systemic inflammatory response syndrome (SIRS) in patients undergoing flexible ureteroscopic lithotripsy based on enhanced recovery after surgery (ERAS). Methods: The clinical data of 243 kidney stone cases who underwent flexible ureteroscopic lithotripsy based on ERAS in the First Affiliated Hospital of Wannan Medical College from January 2016 to December 2017 were analyzed retrospectively. The cases were divided into two groups according to whether they had SIRS after surgery: SIRS group (26 cases) and non-SIRS group (217 cases). The age, gender, laterality of kidney stone, history of previous kidney stone surgery, degree of hydronephrosis, multiple kidney stones, length of operation time, white blood cell count of preoperative urine routine, result of preoperative urine culture, use of preoperative antibiotics, diabetes and other chronic diseases in the groups were collected and analyzed. Results: SIRS occurred in 26 cases in this study, which accounted for 10.7% (26/243). Multivariate analysis found that, moderate and severe hydronephrosis (OR=6.711, P=0.008), stone burden ≥2 cm (OR=10.353, P<0.001), length of operation time ≥ 60 min (OR=5.583, P=0.011), white blood cell count of preoperative urine routine ≥25×10(6)/L (OR=6.195, P=0.005), positive preoperative urine culture (OR=4.216, P=0.011), diabetes and other chronic diseases (OR=4.532, P=0.006) were the independent risk factors for postoperative SIRS (P<0.05). Conclusions: The occurrence of SIRS after flexible ureteroscopic lithotripsy based on ERAS is closely correlated with hydronephrosis, stone burden, length of operation time, white blood cell count of preoperative urine routine, positive preoperative urine culture, diabetes and other chronic diseases.

[Treatment strategies of complex lesions in patients with acute Stanford type A dissection of important branches involvement]

Acute Stanford type A aortic dissection with important branches involved is more complex, could lead to organ malperfusion syndrome even organ failure. The understanding of pathological anatomy, classification, staging, and the pathophysiological change has increasingly mature, but not complete. In addition, the treatment strategy for complex lesions is diversified, some questions may not reach consensus. Fully understanding of the anatomical and pathophysiology is very important for surgeons to choose reasonable treatment strategy. As the rapid development of the basic research, imaging techniques and the concept of surgery procedures, the manage technique of Stanfrod type A dissection and branch vessels at the same time is getting seriously, the related issues also need further discussions.

Association between personal basic information, sleep quality, mental disorders and erectile function: a cross-sectional study among 334 Chinese outpatients

Male erectile dysfunction (ED) may cause anxiety and depression, while mental disorders and sleep disturbances may also be closely related to ED. However, the exact nature of their relationship remains unclear, and whether personal basic background data affect erectile function is unknown. We conducted a cross-sectional study among Chinese outpatients with ED from January 2012 to December 2014. All the men answered a questionnaire collecting information about mental health status, sleep disturbances and personal data, underwent a physical examination and had a blood sample drawn. Sleep disturbances were assessed on the basis of a 19-item version of the Pittsburgh Sleep Quality Index, which includes questions on sleep patterns during the past month. Among the 462 patients, 128 patients with alcohol abuse, diabetes, hypertension, hyperlipidaemia, psychiatric drugs, neurologic injury or abnormal hormones were excluded from the study; 86.27% and 68.66% of the patients suffered from anxiety and depression respectively. Sleep quality and anxiety symptoms significantly affected erectile function, whereas personal income and education level had no significant effects. Our study suggested that it is necessary to pay attention to the psychological status of patients with ED, especially anxiety disorder. Sleep quality may be an important factor affecting erectile function according to the personal data.

Synchronization of time-delayed chemically coupled burst-spiking neurons with correlated noises

Synchronization of two time-delayed chemically coupled neurons with burst-spiking states is studied. Different from the previous study by N. Buric et al. (Phys. Rev. E 78, 036211 (2008)), it is found that exactly synchronous burst-spiking dynamics can occur for small coupling strengths and time delays. The results are confirmed by common time delays and non-equal time delays. When common noise is added to the two neurons, synchronization is enhanced as noise strength is increased. But the results are different for larger time delay and smaller time delay. When noises are correlated, it is found that only strong noises with large correlation coefficient can induce exact synchronization. Even one percent of independent noises can influence synchronization much.

Free-energy-based lattice Boltzmann model for the simulation of multiphase flows with density contrast

A free-energy-based phase-field lattice Boltzmann method is proposed in this work to simulate multiphase flows with density contrast. The present method is to improve the Zheng-Shu-Chew (ZSC) model [Zheng, Shu, and Chew, J. Comput. Phys. 218, 353 (2006)] for correct consideration of density contrast in the momentum equation. The original ZSC model uses the particle distribution function in the lattice Boltzmann equation (LBE) for the mean density and momentum, which cannot properly consider the effect of local density variation in the momentum equation. To correctly consider it, the particle distribution function in the LBE must be for the local density and momentum. However, when the LBE of such distribution function is solved, it will encounter a severe numerical instability. To overcome this difficulty, a transformation, which is similar to the one used in the Lee-Lin (LL) model [Lee and Lin, J. Comput. Phys. 206, 16 (2005)] is introduced in this work to change the particle distribution function for the local density and momentum into that for the mean density and momentum. As a result, the present model still uses the particle distribution function for the mean density and momentum, and in the meantime, considers the effect of local density variation in the LBE as a forcing term. Numerical examples demonstrate that both the present model and the LL model can correctly simulate multiphase flows with density contrast, and the present model has an obvious improvement over the ZSC model in terms of solution accuracy. In terms of computational time, the present model is less efficient than the ZSC model, but is much more efficient than the LL model.

Chemical looping combustion of biomass-derived syngas using ceria-supported oxygen carriers

Cu, Ni and Fe oxides supported on ceria were investigated for their performance as oxygen carriers during the chemical looping combustion of biomass-derived syngas. A complex gas mixture containing CO, H2, CO2, CH4 and other hydrocarbons was used to simulate the complex fuel gas environment derived from biomass gasification. Results show that the transfer of the stored oxygen into oxidants for the supported Cu and Ni oxides at 800°C for the combustion of syngas was effective (>85%). The unsupported Cu oxide showed high oxygen carrying capacity but particle sintering was observed at 800°C. A reaction temperature of 950°C was required for the supported Fe oxides to transfer the stored oxygen into oxidants effectively. Also, for the complex fuel gas environment, the supported Ni oxide was somewhat effective in reforming CH4 and other light hydrocarbons into CO, which may have benefits for the reduction of tar produced during biomass pyrolysis.

Piezoelectric driven non-toxic injector for automated cell manipulation

Stimulated by state-of-the-art robotic and computer technology, Intra Cytoplasmic Sperm Injection (ICSI) automation aims to scale and seamlessly transfer the human hand movements into more precise and fast movements of the micro manipulator. Piezo-drill cell injection, a novel technique using piezo-driven pipettes with a very small mercury column, has significantly improves the survival rates of ICSI process. It is found that complications are due, in large part, to toxicity of mercury and the damage to the cell membrane because of the lateral tip oscillations of injector pipette. In this paper, a new design of piezo-driven cell injector is proposed for automated suspended cell injection. This new piezo-driven cell injector design centralizes the piezo oscillation power on the injector pipette which eliminates the vibration effect on other parts of the micromanipulator. Detrimental lateral tip oscillations of the injector pipette are attenuated to a desirable level even without the help of mercury column. This mercury-free injector can sublime the piezoelectric driven injection technique to completely non-toxic level with great research and commercial application in gene injection, in-vitro fertilization, ICSI and drug development.

Synchronization with on-off coupling: Role of time scales in network dynamics

We consider the problem of synchronizing a general complex network by means of the on-off coupling strategy; in this case, the on-off time scale is varied from a very small to a very large value. In particular, we find that when the time scale is comparable to that of node dynamics, synchronization can also be achieved and greatly optimized for the upper bound of the stability region which nearly disappears, and the synchronization speed is accelerated a lot, independent of network topologies. Our study indicates that the time scale for network variation is of crucial importance for network dynamics and synchronization under the comparable time scale which is much more advantageous over other time scales. Both analysis and experiments confirm the conclusions.

Retrospective analysis of thyroid nodules by clinical and pathological characteristics, and ultrasonographically detected calcification correlated to thyroid carcinoma in South China

OBJECTIVE

To investigate the clinical and pathological characteristics of thyroid nodules, as well as to evaluate the significance of ultrasonographically detected thyroid calcification in the diagnosis of thyroid carcinomas.

METHODS

Retrospective data were studied from 1,051 consecutive patients who underwent a thyroidectomy in the Provincial Hospital of Fujian Medical University in South China between January 2003 and July 2006 for nodular thyroid disease. Complete sonographical information before surgery was only collected from 758 of the 1,051 patients.

RESULTS

Among the 1,051 patients, benign lesions were found in 857 (81.54%) patients, of whom 612 (71.41%) were nodular goiter; malignant lesions were found in 194 (18.46%) patients, in whom benign thyroid lesions were also found in 85 (43.81%) patients. A total of 48 patients suffered from microcarcinomas, of whom 37 patients had benign lesions; these 37 accounted for 43.53 and 77.08%, respectively, of the 85 malignant cases with benign lesions and the 48 cases with microcarcinomas. In the 758 patients who underwent thyroid ultrasonography before surgery, intrathyroidal calcifications were apparent in 243 patients (32.06%). The incidence of calcification was significantly higher in patients with thyroid carcinoma (54.17%) than in those with benign lesions (26.87%; p < 0.005). Detection of calcification in thyroid lesions by ultrasound had a sensitivity of 32.38% and a specificity of 87.35%, with an OR of 3.31 (95% CI, 2.24-4.63), positive likelihood ratio of 2.56, negative likelihood ratio of 0.77 and a kappa value of 0.23.

CONCLUSION

Thyroid carcinoma, especially microcarcinoma, often coexists with benign thyroid disease. Calcification detected by thyroid ultrasound represents a risk factor for malignancy, but is of limited use as a sole marker of malignancy.

Predicting the synchronization time in coupled-map networks

An analytical expression for the synchronization time in coupled-map networks is given. By means of the expression, the synchronization time for any given network can be predicted accurately. Furthermore, for networks in which the distributions of nontrivial eigenvalues of coupling matrices have some unique characteristics, analytical results for the minimal synchronization time are given.

The correlation between neurotoxicity, aggregative ability and secondary structure studied by sequence truncated Abeta peptides

Aggregated beta-amyloid (Abeta) peptides are neurotoxic and cause neuronal death both in vitro and in vivo. Although the formation of a beta-sheet structure is usual required to form aggregates, the relationship between neurotoxicity and the Abeta sequence remains unclear. To explore the correlation between Abeta sequence, secondary structure, aggregative ability, and neurotoxicity, we utilized both full-length and fragment-truncated Abeta peptides. Using a combination of spectroscopic and cellular techniques, we demonstrated that neurotoxicity and aggregative ability are correlated while the relationship between these characteristics and secondary structure is not significant. The hydrophobic C-terminus, particularly the amino acids of 17-21, 25-35, and 41-42, is the main region responsible for neurotoxicity and aggregation. Deleting residues 17-21, 25-35 or 41-42 significantly reduced the toxicity. On the other hand, truncation of the peptides at either residues 22-24 or residues 36-40 had little effect on toxicity and aggregative ability. While the N-terminal residues 1-16 may not play a major role in neurotoxicity and aggregation, a lack of N-terminal fragment Abeta peptide, (e.g. Abeta17-35), does not display the neurotoxicity of either full-length or 17-21, 25-35 truncated Abeta peptides.

Chaotic synchronization in large map networks

The chaotic synchronization in n-dimensional large map networks with local coupling and their size stabilities in the node number N-->infinity are studied analytically and numerically. The analytical results show that the chaotic synchronization is stable for N-->infinity in the presence of the external driving or global coupling. The numerical calculations show that, as the driving or global interaction strength increases from zero, the network states have the whole route: spatiotemporal chaotic state --> cluster chaotic synchronous state --> complete chaotic synchronous state --> spatiotemporal pattern --> spatiotemporal chaotic state.

The Effect of Aβ Conformation on the Metal Affinity and Aggregation Mechanism Studied by Circular Dichroism Spectroscopy

The conformational change and associated aggregation of beta amyloid (Abeta) with or without metals is the main cause of Alzheimer's disease (AD). In order to further understand the effects of Abeta and its associated metals on the aggregation mechanism, the influence of Abeta conformation on the metal affinity and aggregation was investigated using circular dichroism (CD) spectroscopy. The Abeta conformation is dependent on pH and trifluoroethanol (TFE). The binding of metals to Abeta was found to be dependent on the Abeta conformation. The aggregation induced by Abeta itself or its associated metals is completely diminished for Abeta in 40% TFE. Only in 5% and 25% TFE can Abeta undergo an alpha-helix to beta-sheet aggregation, which involve a three-state mechanism for the metal-free state, and a two-state transition for the metal-bound state, respectively. The aggregation-inducing activity of metals is in the order, Cu2+ > Fe3+ > or = Al3+ > Zn2+.

Coexistence of anticipated and layered chaotic synchronization in time-delay systems

We study the dynamic stabilities of unidirectionally coupled linear arrays of chaotic oscillators with time-delay feedbacks in star configuration, and find that if all oscillators in the network are identical, then the oscillators in the linear arrays can anticipate the driving oscillators, and simultaneously the oscillators in the linear arrays with the same position with respect to the central one are in synchronous chaotic state. Compared with the anticipated synchronization, the layered synchronization is first generated and last destroyed as the coupling constant is increased. This coexistence of anticipated and layered chaotic synchronization is destroyed by long time feedback. If the driving and driven oscillators are different, then only layered chaotic synchronization is possible.

Layered synchronous propagation of noise-induced chaotic spikes in linear arrays

Stable propagation of noise-induced synchronous spiking in uncoupled linear neuron arrays is studied numerically. The chaotic neurons in the unidirectionally coupled linear array are modeled by Hindmarsh-Rose neurons. Stability analysis shows that the synchronous chaotic spiking can be successfully transmitted to cortical areas through layered synchronization in the neural network under certain conditions of the network structure.

Preparation and Characterization of Straight and Zigzag AlN Nanowires

Hexagonal single-crystal AlN nanowires with straight or zigzag morphologies were successfully synthesized by the reaction of aluminum alloy in an ammonia/nitrogen atmosphere at 1100 degrees C. It is found that the crystal tropism of the nanowires is along [0001], whereas the growth directions of the zigzag nanowires shift between [2111] and [2111].

Long-time anticipation of chaotic states in time-delay coupled ring and linear arrays

We study the time-delay and unidirectionally coupled ring and linear arrays of chaotic systems, and find that under certain conditions, the linear array can spatial periodically "copy" the chaotic dynamics of the ring with very long anticipation times. Numerical calculations of the Lyapunov exponents show that the delay times can result in unsynchronized chaotic waves, periodic waves, and stable states in the ring that are replicated in the linear array, but have no effect on the absolute stability of the anticipatory synchronization. Our results show that such configurations can both enhance the absolute stability of the synchronization manifolds and minimize the effects of convective instabilities.

Determination of the orbital polarization in YTiO3 by using soft X-ray linear dichroism

We report measurements of linear dichroism in x-ray absorption at Ti L(2,3) edges of a Mott-insulating ferromagnet YTiO3, where orbital ordering occurs in the triply degenerate Ti 3d t(2g) states. Dichroic spectra and their integrated intensities are obtained for the incident electric field with polarizations parallel to a, b, and c axes. The comparison of the spectra with atomic multiplet calculations removes the ambiguity about the orbital polarization, i.e., the relative weights of |xy>, |yz>, and |zx> orbits, which are crucial for the origin of ferromagnetism. The result is consistent with the previous analysis of nuclear magnetic resonance in the Mizokawa-Fujimori scheme.

Orbital ordering in La0.5Sr1.5MnO4 studied by soft X-ray linear dichroism

We found that the conventional model of orbital-ordering of 3x(2)-r(2)/3y(2)-r(2) type in the e(g) states of La0.5Sr1.5MnO4 is incompatible with measurements of linear dichroism in the Mn 2p-edge x-ray absorption, whereas these e(g) states exhibit predominantly cross-type orbital ordering of x(2)-z(2)/y(2)-z(2). LDA+U band-structure calculations reveal that such a cross-type orbital-ordering results from a combined effect of antiferromagnetic structure, Jahn-Teller distortion, and on-site Coulomb interactions.

Spatial periodic synchronization of chaos in coupled ring and linear arrays of chaotic systems

Dynamic behaviors of coupled ring and linear arrays of unidirectionally coupled Lorenz oscillators are studied numerically. It is found that the chaotic rotating waves generated from the ring propagate with spatial periodic synchronization along the linear array, that is to say, two chaotic oscillators in the linear array are synchronized if the number of oscillators (spatial distance) between them is a multiple of oscillator number in the ring. Numerically it is shown that the stabilities of the synchronized states are enhanced by chaos, and degraded when the oscillators are far from the ring.

Purification and Characterization of a Chymotrypsin Inhibitor from the Venom of Ophiophagus hannah (King Cobra)

A chymotrypsin inhibitor from the venom of Ophiophagus hannah was isolated by a combination of ion-exchange chromatography and reverse phase HPLC. Amino acid sequence analysis revealed that this protein consists of 58 amino acids, six of these being cysteine residues and is highly homologous to Kunitz-type protease inhibitors. ESI-mass spectrum showed that the protein had a mass of 6493, which is in agreement with that predicted from its primary structure. In contrast to P1 Leu, Met, Phe, Trp, and Tyr appearing in other chymotrypsin inhibitors, a P1 Asn in the novel inhibitor may cause a weak binding (Ki = 3.52 microM) with chymotrypsin. Phylogenetic analysis suggests that the functional variations of the chymotrypsin inhibitor and other Kunitz-type inhibitors probably distinguish from dendrotoxins by accelerated evolution.

Protein phosphatase 1 regulation by inhibitors and targeting subunits

Regulation of protein phosphatase 1 (PP1) by protein inhibitors and targeting subunits has been previously studied through the use of recombinant protein expressed in Escherichia coli. This preparation is limited by several key differences in its properties compared with native PP1. In the present study, we have analyzed recombinant PP1 expressed in Sf9 insect cells using baculovirus. Sf9 PP1 exhibited properties identical to those of native PP1, with respect to regulation by metals, inhibitor proteins, and targeting subunits, and failure to dephosphorylate a phosphotyrosine-containing substrate or phospho-DARPP-32 (Dopamine and cAMP-regulated phosphoprotein, M(r) 32,000). Mutations at Y272 in the beta12/beta13 loop resulted in a loss of activity and reduced the sensitivity to thiophospho-DARPP-32 and inhibitor-2. Mutations of Y272 also increased the relative activity toward a phosphotyrosine-containing substrate or phospho-DARPP-32. Mutation of acidic groove residues caused no change in sensitivity to thiophospho-DARPP-32 or inhibitor-2, but one mutant (E252A:D253A:E256R) exhibited an increased K(m) for phosphorylase a. Several PP1/PP2A chimeras were prepared in which C-terminal sequences of PP2A were substituted into PP1. Replacement of residues 274-330 of PP1 with the corresponding region of PP2A resulted in a large loss of sensitivity to thiophospho-DARPP-32 and inhibitor-2, and also resulted in a loss of interaction with the targeting subunits, spinophilin and PP1 nuclear targeting subunit (PNUTS). More limited alterations in residues in beta12, beta13, and beta14 strands highlighted a key role for M290 and C291 in the interaction of PP1 with thiophospho-DARPP-32, but not inhibitor-2.

The multiplicity of cardiotoxins from Naja naja atra (Taiwan cobra) venom

Four novel cardiotoxins were isolated from Naja naja atra (Taiwan cobra) venom by successive separation on a SP-Sephadex C-25 column and a reverse phase column. Amino acid sequences of the cardiotoxins were determined by Edman degradation and carboxypeptidase digestion. It shows that these cardiotoxins comprise 60 amino acid residues. Comparative analyses on the amino acid sequences of cardiotoxins from the venoms of N. naja atra and other Naja species indicated that amino acid substitutions of cardiotoxin isoforms frequently occurred at positions 7-11, 27-32 and 45-47. The hypervariable segments encoded by the second and third exon of cardiotoxin genes are located at or near the tips of loop structure of cardiotoxin molecules. These results, together with the suggestions that the residues at the tips of cardiotoxins' loop structure were involved in the manifestation of the biological activities of cardiotoxins, reflect that the preferential mutations may contribute to alterations in the function of cardiotoxin molecules. Analysis on the secondary structure of pre-mRNAs of N. naja atra cardiotoxin 4 gene and N. naja sputatrix cardiotoxin 3 gene has shown that the hypervariable regions of the exon 2 pertain to form intra-exon pairings and are not involved in the formation of intron-exon pairings. Since the pairings of splice sites and gene architecture were supposed to be associated with intron-exon recognition, it is likely that the preferred loci of mutations occurring with the evolution of cardiotoxin genes would not affect the processing of cardiotoxin precursors.

Circumvention of tumor multidrug resistance by a new annonaceous acetogenin: atemoyacin-B

AIM

To explore the effect of atemoyacin-B (Ate) on overcoming multidrug resistance (MDR).

METHODS

Bullatacin (Bul) was used as a positive control. Cytotoxic effects of Bul and Ate were studied with cell culture of human MDR breast adenocarcinoma cells, MCF-7/Dox and human KBv200 cells, and their parental sensitive cell lines MCF-7 and KB. Cytotoxicity was determined by tetrazolium (MTT) assay. The function of P-glycoprotein (P-gp) was examined by Fura 2-AM assay. Cellular accumulation of doxorubicin (Dox) was determined by fluorescence spectrophotometry. Apoptosis was measured by flow cytometry.

RESULTS

IC50 of Ate for MCF-7/Dox, MCF-7, KBv200, and KB cells were 122, 120, 1.34, and 1.27 nmol.L-1, respectively. IC50 of Bul for MCF-7/Dox, MCF-7, KBv200, and KB cells were 0.60, 0.59, 0.04, and 0.04 nmol.L-1, respectively. The cytotoxicities of Bul and Ate to MDR cells were similar to those to parental sensitive cells. Bul and Ate markedly increased cellular Fura-2 and Dox accumulation in MCF-7/Dox cells, but not in MCF-7 cells. The rates of apoptosis in MDR cells were similar to those in sensitive cells induced by Ate.

CONCLUSION

There was no cross-resistance of P-gp positive MCF-7/Dox and KBv200 cell lines to Bul and Ate as compared with their sensitive P-gp negative MCF-7 and KB cell lines. The mechanism of the circumvention of MDR was associated with the decrease of P-gp function and the increase of cellular drug accumulation in MDR cells.

Characterization of the inhibition of protein phosphatase-1 by DARPP-32 and inhibitor-2

Phospho-DARPP-32 (where DARPP-32 is dopamine- and cAMP-regulated phosphoprotein, Mr 32,000), its homolog, phospho-inhibitor-1, and inhibitor-2 are potent inhibitors (IC50 approximately 1 nM) of the catalytic subunit of protein phosphatase-1 (PP1). Our previous studies have indicated that a region encompassing residues 6-11 (RKKIQF) and phospho-Thr-34, of phospho-DARPP-32, interacts with PP1. However, little is known about specific regions of inhibitor-2 that interact with PP1. We have now characterized in detail the interaction of phospho-DARPP-32 and inhibitor-2 with PP1. Mutagenesis studies indicate that within DARPP-32 Phe-11 and Ile-9 play critical roles, with Lys-7 playing a lesser role in inhibition of PP1. Pro-33 and Pro-35 are also important, as is the number of amino acids between residues 7 and 11 and phospho-Thr-34. For inhibitor-2, deletion of amino acids 1-8 (I2-(9-204)) or 100-204 (I2-(1-99)) had little effect on the ability of the mutant proteins to inhibit PP1. Further deletion of residues 9-13 (I2-(14-204)) resulted in a large decrease in inhibitory potency (IC50 approximately 800 nM), whereas further COOH-terminal deletion (I2-(1-84)) caused a moderate decrease in inhibitory potency (IC50 approximately 10 nM). Within residues 9-13 (PIKGI), mutagenesis indicated that Ile-10, Lys-11, and Ile-13 play critical roles. The peptide I2-(6-20) antagonized the inhibition of PP-1 by inhibitor-2 but had no effect on inhibition by phospho-DARPP-32. In contrast, the peptide D32-(6-38) antagonized the inhibition of PP1 by phospho-DARPP-32, inhibitor-2, and I2-(1-120) but not I2-(85-204). These results indicate that distinct amino acid motifs contained within the NH2 termini of phospho-DARPP-32 (KKIQF, where italics indicate important residues) and inhibitor-2 (IKGI) are critical for inhibition of PP1. Moreover, residues 14-84 of inhibitor-2 and residues 6-38 of phospho-DARPP-32 share elements that are important for interaction with PP1.

The design, synthesis, and biological evaluation of analogues of the serine-threonine protein phosphatase 1 and 2A selective inhibitor microcystin LA: rational modifications imparting PP1 selectivity

Based on the results from previously reported molecular modeling analyses of the interactions between the inhibitor microcystin and the serine-threonine protein phosphatases 1 and 2A, we have designed analogues of microcystin LA with structural modifications intended to impart PP1 selectivity. The synthesis of several first generation analogues followed by inhibition assays revealed that all three are PP1-selective, as predicted. Although the observed selectivities are modest, one of the designed analogues is more selective for PP1 than any known small molecule inhibitor.

Development and characterization of genetic mapping resources for the turkey (Meleagris gallopavo)

The development and partial characterization of turkey genomic libraries enriched for TG, GAT, and CCT simple sequence repeats (SSR) are described. The primary library, established using conventional methods, was enriched for each of the three SSR by single-primer polymerase chain reaction (PCR). The three enriched libraries were screened by standard hybridization and washing protocols under moderate to high stringency conditions. The utility of a fraction of the markers was evaluated based on the polymorphism of PCR-amplified products in a backcross reference DNA panel. The panel consisted of genomic DNA samples from three backcrossed families developed from a cross of a wild male turkey to three inbred Orlopp line C females. A total of 181 sequences from positive clones have been characterized and deposited in GenBank. About 60% of the 60 primer pairs designed from SSR-containing sequences detected polymorphism in the reference DNA panel. The turkey genomic DNA reference panel, the enriched libraries, and the markers described here provide an opportunity to begin to characterize the turkey genome and to develop a useful public genetic map for this economically important species.

Characterization and cloning of long neurotoxin homolog from Naja naja atra

The cDNA encoding a long neurotoxin homolog was constructed from the cellular RNA isolated fom the venom glands of Naja naja atra (Taiwan cobra) by reverse transcription-polymerase chain reaction. BLAST searches for sequence similarity in the GenBank databases reveal that the cDNA sequence of the long neurotoxin homolog is not highly homologous with long and short neurotoxins. Although the long neurotoxin homolog exhibited an activity to inhibit acetylcholine-induced muscle contractions as Naja naja atra cobrotoxin, the degree of inhibition caused by the addition of long neurotoxin homolog was only approximately 35% of that observed with the addition of cobrotoxin. Moreover, the primary structure of the long neurotoxin homolog did not fulfill the characteristic features of long or short neurotoxins. Together with long neurotoxin homologs from other snake species, they probably represent an evolutionary divergence between long and short neurotoxins.

Characterization of the interaction between DARPP-32 and protein phosphatase 1 (PP-1): DARPP-32 peptides antagonize the interaction of PP-1 with binding proteins

The catalytic subunit of PP-1 (PP-1C) is potently inhibited (IC50, approximately 1 nM) by DARPP-32 (dopamine- and cAMP-regulated phosphoprotein, M(r) 32,000), inhibitor-1, and inhibitor-2. The NH2-terminal 50 amino acid residues of DARPP-32 and inhibitor-1 are similar, and phosphorylation of a common threonine residue (Thr-34/Thr-35) is necessary for inhibition of PP-1C. We have characterized further the interaction between DARPP-32 and PP-1C. Using synthetic peptides derived from the NH2-terminal region of DARPP-32, residues 6-11, RKKIQF, have been shown to be required for inhibition of PP-1C. Peptides containing this motif were able to antagonize the inhibition of PP-1C by phospho-DARPP-32 and phosphoinhibitor-1. The inhibition of PP-1C by inhibitor-2, but not by okadaic acid, microcystin, or calyculin A, was also attentuated by these antagonist peptides. These results together with results from other studies support a model in which two subdomains of phospho-DARPP-32 interact with PP-1C. The region encompassing phospho-Thr-34 appears to interact with the active site of the enzyme blocking enzyme activity. The region encompassing the RKKIQF motif binds to a domain of PP-1C removed from the active site. Amino acid sequence analysis indicates that basic and hydrophobic features of the RKKIQF motif are conserved in the binding domains of certain PP-1C targeting proteins, suggesting that interaction of inhibitor proteins and targeting proteins may be mutually exclusive.

Site-directed mutagenesis of amino acid residues of protein phosphatase 1 involved in catalysis and inhibitor binding

Site-directed mutagenesis of selected residues of mammalian protein phosphatase 1 (PP-1) has been carried out to further define the mechanism of catalysis, activation by divalent cations, and inhibition by toxins and inhibitory proteins. Mutation of active site residues predicted to bind metals (N124D and H248N) resulted in a large loss of enzyme activity and decreased affinity for metal ions; mutation of residues predicted to bind phosphosubstrate (R96A or R221S) led to a large loss of enzyme activity; and mutation of active site residues (D95A and D208A) resulted in a large loss of enzyme activity. Mutants N124D, H248N, R96A, and R221S exhibited large decreases in sensitivity to the toxins calyculin A, okadaic acid, and microcystin and to thiophospho-DARPP-32. Mutation of Y272 (Y272F) had little effect on activity but resulted in a large decrease in sensitivity to okadaic acid and calyculin A. Mutant D208A exhibited a decrease in sensitivity to okadaic acid and calyculin A, but, paradoxically, the sensitivity to inhibition by thiophospho-DARPP-32 was increased. Mutation of acidic groove residues (E256R, E275R, E252A:D253A, and E252A:D253A:E256R) exhibited little change in enzyme activity and no change in sensitivity to toxins, but increased sensitivity to thiophospho-DARPP-32. These results suggest that toxins and phospho-DARPP-32 interact at the active site of PP-1 in a similar fashion despite their differences in structure. In addition, acidic groove residues appear to influence the interaction of the phosphoinhibitor with the active site of PP-1.

Three-dimensional structure of the catalytic subunit of protein serine/threonine phosphatase-1

The crystal structure of mammalian protein phosphatase-1, complexed with the toxin microcystin and determined at 2.1 A resolution, reveals that it is a metalloenzyme unrelated in architecture to the tyrosine phosphatases. Two metal ions are positioned by a central beta-alpha-beta-alpha-beta scaffold at the active site, from which emanate three surface grooves that are potential binding sites for substrates and inhibitors. The carboxy terminus is positioned at the end of one of the grooves such that regulatory sequences following the domain might modulate function. The fold of the catalytic domain is expected to be closely preserved in protein phosphatases 2A and 2B (calcineurin).

Postantibiotic effect of ceftibuten on respiratory pathogens

The postantibiotic effect (PAE) of ceftibuten, a novel beta-lactamase-stable cephem, was determined for Streptococcus pyogenes, Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. The ceftibuten PAE after a 2-hour exposure to 2 micrograms/ml (4 x minimum inhibitory concentration) for S. pyogenes was 2.7 to > 10 hours. The PAE for S. pneumoniae after a 2-hour exposure to 15 micrograms/ml, concentrations that are achieved in man after usual therapeutic doses, was 1.1 to 3.4 hours and the PAE for H. influenzae was 1 to 1.1 hours. M. catarrhalis had a PAE of 1.5 to 1.8 hours after exposure to 15 micrograms/ml of ceftibuten. The ceftibuten PAE was not affected by serum. The ceftibuten PAE was prolonged by exposure to a sub-minimum inhibitory concentration concentration of ceftibuten as would occur in the clinical situation. The PAE of ceftibuten was not affected by the copresence of erythromycin as would occur when treating infections in which atypical organisms are suspected. There was no correlation between bacterial reduction in colony-forming units and the duration of PAE. A level of 6 micrograms/ml of ceftibuten had a similar bacterial killing activity compared with a 6-hour exposure to 15 micrograms/ml of ceftibuten against S. pneumoniae, H. influenzae and M. catarrhalis. This study suggests that ceftibuten can be administered orally, once daily in an adult dose of 400 mg or a pediatric dose of 9 mg/kg, to treat respiratory infections caused by the most common pathogens.

Mechanism of inhibition of protein phosphatase 1 by DARPP-32: studies with recombinant DARPP-32 and synthetic peptides

The mechanism of inhibition of protein phosphatase-1 catalytic subunit (PP-1c) by recombinant DARPP-32 and synthetic peptides was studied. DARPP-32 was expressed in Escherichia coli as a non-fusion protein using a pEt-3a plasmid, purified to homogeneity and shown to have physicochemical properties similar to those of the protein purified from bovine brain. Recombinant DARPP-32 phosphorylated on threonine-34 by cAMP-dependent protein kinase inhibited PP-1c with an IC50 approximately 0.5 nM, comparable to that obtained with bovine DARPP-32. Non-phosphorylated DARPP-32, and mutated forms in which threonine-34 was replaced by an alanine or a glutamic acid, inhibited PP-1c with an IC50 approximately 1 microM. Surface plasmon resonance analysis showed binding of PP-1c to nonphospho- and phospho-DARPP-32-(8-38) synthetic peptides with apparent Kd values of 1.2 and 0.3 microM, respectively, supporting the existence of an interaction between non-phosphorylated DARPP-32 and PP-1c that is increased by phosphorylation of DARPP-32 at threonine-34. These results suggest a model in which DARPP-32 interacts with PP-1c by at least two low affinity sites, the combination of which is responsible for the high affinity (nM) inhibition.

In vitro activity of SCE-2787, a new cephalosporin with potent activity against Pseudomonas aeruginosa and members of the family Enterobacteriaceae

The in vitro activity of SCE-2787, 7-[(Z)-2-(5-amino-1,2,4-thiadiazol-3- yl)-2-methoxyiminoacetamido]-3-(1-imidazo[1,2-b]pyridazinium)methy l-3- cephem-4-carboxylate, was compared with those of ceftazidime, ceftriaxone, and imipenem against recent clinical isolates. SCE-2787 inhibited 50% of tested isolates of the family Enterobacteriaceae at < or = 0.25 micrograms/ml. SCE-2787 was equally active as or more active than ceftazidime and ceftriaxone against members of the Enterobacteriaceae, with the exception of Proteus vulgaris. The MIC of SCE-2787 at which 90% of the isolates of Pseudomonas aeruginosa were inhibited was 2 micrograms/ml, two- to fourfold lower than those of imipenem and ceftazidime, respectively. SCE-2787, like ceftazidime and imipenem, did not inhibit the majority of strains of Pseudomonas cepacia and Xanthomonas maltophilia. SCE-2787 inhibited beta-hemolytic streptococci at < or = 0.12 micrograms/ml, but it did not inhibit Enterococcus faecalis, Listeria monocytogenes, or the anaerobic species tested. Methicillin-resistant staphylococci required SCE-2787 MICs of > or = 16 micrograms/ml, whereas methicillin-susceptible staphylococci were inhibited by 2 micrograms/ml. No difference between the MICs and MBCs was noted, except for P. aeruginosa, for which there was a fourfold difference. SCE-2787 was active over a pH range of 6 to 8. The inoculum size of 10(5) to 10(7) CFU caused only a twofold change in the MIC for Escherichia coli and Staphylococcus aureus but a 4- to 16-fold change in Enterobacter cloacae and P. aeruginosa. beta-Lactamases from Bush groups 1, 2a, and 2b did not hydrolyze SCE-2787. There was significant hydrolysis of SCE-2787 by the beta-lactamases designated 2b', i.e., TEM-3, TEM-5, TEM-7, and TEM-9, and by the group 2d beta-lactamases. SCE-2787 had poor affinity for group 1 and group 2b enzymes and constitutively produced chromosomal beta-lactamases such as P-99 of Enterobacter cloacae and plasmid-mediated TEM-1 of E. coli. SCE-2787 has in vitro activity comparable to that of current parenteral cephalosporin and is more active against P. aeruginosa and S. aureus.

Amino acid sequence and properties of vasopressin-associated elephant neurophysin

The primary structure of an elephant neurophysin, homologous to vasopressin-associated neurophysins, is reported. The protein contains a Tyr for Asn substitution at position 75, a position in direct contact with residues 77 and 78 of the monomer-monomer interface. This Tyr residue therefore serves as a potential reporter of the path involved in the long-range linkage between peptide binding and dimerization in this system. NMR studies of the protein in unliganded and liganded states demonstrated normal dimerization properties and the expected increase in dimerization associated with binding peptide. In keeping with an elevated pKa of 11.1 assigned to Tyr-75 by UV spectrophotometric titration, the NMR signals from the 3,5 and 2,6 ring protons of Tyr-75 were shifted 0.3 and 0.2 ppm upfield, respectively, relative to their positions in small peptides, indicating significant shielding and/or hydrogen bonding. The Tyr-75 ring proton signals narrowed slightly, with no discernible change in chemical shift, on conversion from dimer to monomer in the unliganded state. Ring protons of Tyr-49, distant from the monomer-monomer interface, but adjacent to the peptide-binding site, were markedly perturbed by dimerization, in accord with their behavior in bovine neurophysins. The results suggest that the secondary and tertiary structure of the region 75-78 is largely unchanged by dimerization, and argue against an important role for this region in dimerization-mediated conformational changes that alter the binding site in the unliganded state.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro activity and beta-lactamase stability of FK-037, a parenteral cephalosporin

The in vitro activity of FK-037, 5-amino-2-[[(6R, 7R)-7-[[(Z)-2-(2-amino-4-thiazolyl)-2- methoxyimino) acetyl] amino]-2-carboxy-8-oxo-5-thia-1- azabicyclo[4.2.0]oct-2-en-3-yl]methyl]-1-(2-hydroxyethyl)-1H-pyrazoli um hydroxide, inner salt, sulfate (1:1), a new parenteral cephem, was compared with those of cefepime, ceftazidime, imipenem, and ciprofloxacin. FK-037 inhibited methicillin-susceptible staphylocci at < or = 4 micrograms/ml. Of 98 isolates of homogenous methicillin-resistant Staphylococcus aureus, 55 (56.1%) were inhibited by 8 micrograms of FK-037 per ml, compared to 3.1% for cefepime. Imipenem was the most active beta-lactam tested against staphylococci. The MIC of FK-037 for 90% of the strains tested (MIC90) was 0.06 micrograms/ml for hemolytic streptococci, Streptococcus pneumoniae, viridans group streptococci, and Streptococcus bovis. The MIC90 for many of the members of the family Enterobacteriaceae was 1 microgram/ml, similar to that of cefepime and lower than those of ceftazidime and imipenem. The MIC90 for Klebsiella pneumoniae and Enterobacter cloacae was 8 micrograms/ml, similar to that for cefepime, but all isolates were inhibited by 2 micrograms of imipenem per ml. K. pneumoniae isolates with cefotaxime and ceftazidime MICs of > 32 micrograms/ml with Bush type 2b' beta-lactamases were inhibited by 4 micrograms of FK-037 per ml. E. cloacae, Citrobacter freundii, and S. aureus stably resistant to FK-037 could be selected by repeated transfer in the presence of FK-037. The FK-037 MIC90 for Pseudomonas aeruginosa was 4 microgram/ml, compared to 32 microgram/ml for cefepime and ceftazidime and 8 microgram/ml for imipenem. Xanthomonas maltophilia, Pseudomonas cepacia, Acinetobacter anitratus, and Bacteroides species were resistant to FK-037 (MIC, more than or equal 32 microgram/ml). MBCs were identical to or within twofold of the MICs except for a 32-fold greater MBC for P. aeruginosa. Inoculum size and acid environment did not lower the activity of FK-037. FK-037 was not appreciably hydrolyzed by Bush group 1, 2a, 2b, and 2e beta-lactamases but was hydrolyzed by 2b' and 2d enzymes at rates comparable to that of ceftazidime. Nonetheless, FK-037 inhibited bacteria possessing TEM-3, -5, and -7 and SHV -5 at less than or equal 8 microgram/ml. Overall, FK-037 has lower MICs against staphylococci and P. aeruginosa than the currently available iminomethoxy aminothiazolyl cephalosporins and has activity against members of the family Enterobacteriaceae comparable to that of cefepime.

Slowly interchanging conformers of bovine neurophysin-I in the unliganded dimeric state

The effect of neurophysin dimerization on Tyr-49, a residue adjacent to the hormone-binding site, was investigated by proton NMR in order to analyze the basis of the dimerization-induced increase in neurophysin hormone affinity. Dimerization-induced changes in Tyr-49 resonances, in two unliganded bovine neurophysins, suggested that Tyr-49 perturbation is an intrinsic consequence of dimerization, although Tyr-49 is distant from the monomer-monomer interface in the crystalline liganded state. To determine whether this perturbation reflects a conformational difference between liganded and unliganded states that places Tyr-49 at the interface in the unliganded state, or a dimerization-induced change in secondary (2 degrees) or tertiary (3 degrees) structure, the more general structural consequences of dimerization were further analyzed. No change in 2 degrees structure upon dimerization was demonstrable by CD. On the other hand, a general similarity of regions involved in dimerization in unliganded and liganded states was indicated by NMR evidence of participation of His-80 and Phe-35 in dimerization in the unliganded state; both residues are at the interface in the crystal structure and distant from Tyr-49. Consistent with a lack of direct participation of Tyr-49 at the monomer-monomer interface, dimerization induced at least two distinct slowly exchanging environmental states for the 3.5 ring protons of Tyr-49 without significantly increased dipolar broadening relative to the monomer. Two environments were also found in the dimer of des-1-8 neurophysin-I for the methyl protons of Thr-9, another residue distant from the monomer-monomer interface and close to the binding site in the liganded state.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of the unstable neurophysin disulfide and localization to the hormone-binding site. Relationship to folding-unfolding pathways

For unliganded neurophysin, the effects of reduction of a single disulfide and limited regeneration of activity following reduction have suggested metastable disulfide pairing relative to that of the neurophysin precursor. This metastability was confirmed in the present study by the demonstration of almost complete regeneration of activity from the reduced state in the presence of ligand peptides, conditions mimicking precursor folding. To assign the source of the metastability of the unliganded mature protein, the disulfide(s) most susceptible to reduction and the last to be reoxidized following complete reduction were identified. Partial reduction of the first disulfide followed by trapping of the generated thiols with [14C]iodoacetate gave a distribution of label consistent with identification of the unstable disulfide as the 10-54 bridge and rapid interchange of the Cys-10 thiol with other disulfides in the amino-terminal disulfide domain. The same thiol distribution was seen at the terminal stage of reoxidation following complete reduction, providing evidence that unfolding and folding pathways are the same at this stage. The results indicate that, in the absence of bound peptide, the state with correct pairing of the 10-54 bridge has no significant thermodynamic advantage over interchanged states of the amino-terminal domain. However, since the 10-54 bridge is located at the peptide-binding site, the correct pairing is directly stabilized by ligand peptides. Moreover, since the other three bridges of the amino domain are homologous to bridges in the carboxyl-terminal domain that do not appear to be unstable, the results allow the possibility that the 10-54 bridge, which is unique to the amino domain, destabilizes other disulfides in that domain.

Crystallographic analysis of the neurophysin-oxytocin complex. A preliminary report

Single crystals of a bovine neurophysin II-oxytocin complex have been obtained using (NH4)2SO4 as the precipitating agent. The crystals diffract to at least 2.7 A resolution, belong to Laue group 4/mmm and exhibit systematic absences consistent with either space group P4(1)2(1)2 or P4(3)2(1)2. The cell dimensions are a = b = 69.07 A and c = 113.26 A. The crystals contain one neurophysin-oxytocin dimer per asymmetric unit. Based on a Vm of 2.9 A3/Da, the solvent content is calculated to be 58%. Chromatographic analysis of the dissolved crystals suggests the presence of three oxytocin molecules per neurophysin dimer.

Vaccination against and immune response to viral haemorrhagic disease of rabbits: a review of research in the People's Republic of China

Viral haemorrhagic disease (VHD) of rabbits is an acute entity with high mortality which affects adult rabbits. Several vaccines have been developed in China and extensive use of these vaccines in the field has controlled the spread of the disease. Formalin inactivated tissue vaccine induces solid immunity on the third to fourth day post vaccination and immunity lasts for at least six months. The oil-emulsion tissue vaccine which has been developed has longer lasting potency. Successful adaptation of VHD virus (VHDV) to cultured cells and preliminary immunisation will provide the possibility of large-scale production of cell-cultured virus vaccine. Passive, emergency immunisation with hyperimmune antiserum provides short-term protection of threatened rabbits as well as treatment of infected rabbits in the field. Histopathological and pathophysiological studies reveal that immune cells and organs are the most affected targets in infected rabbits; owing to the damage to the endothelial system of blood vessels, extensive disseminated intravascular coagulation (DIC) occurs in the parenchymal tissues. Destruction of the immune system and the occurrence of DIC lead to acute illness and sudden death post infection. Experimental immunological studies demonstrate that the induction of rapid immunity is coordinated by macrophages and T and B lymphocytes in the initial, post-immunisation stage, whereas humoral immunity plays the main role in long-term protection against VHDV infection. The positive association of post-vaccination protection with haemagglutination inhibition antibody can also be observed. Interferon probably takes effect as an anti-VHDV agent soon after vaccination.