There is nothing permanent except change. The emergence of new virus diseases

Mathematical Modeling of Virus-Mediated Syncytia Formation: Past Successes and Future Directions

Many viruses have the ability to cause cells to fuse into large multi-nucleated cells, known as syncytia. While the existence of syncytia has long been known and its importance in helping spread viral infection within a host has been understood, few mathematical models have incorporated syncytia formation or examined its role in viral dynamics. This review examines mathematical models that have incorporated virus-mediated cell fusion and the insights they have provided on how syncytia can change the time course of an infection. While the modeling efforts are limited, they show promise in helping us understand the consequences of syncytia formation if future modeling efforts can be coupled with appropriate experimental efforts to help validate the models.

Phase transitions and mechanisms of cryoprotection of serum-/xeno-free media based on dextran and dimethyl sulfoxide

The development of serum-/xeno-free media may help avoid the drawbacks of using serum and its components, such as probable contamination, instability of composition, or difficulty in sterilization. The objectives of this research were to investigate the use of combinations of a permeating cryoprotective agent (Me₂SO) and non-permeating (polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, hydroxyethyl starch, dextran) polymers for cryopreservation of interstitial cells (ICs) of rat testis, and to propose the mechanism of cryoprotection of such compositions. In the course of this study, the best combination was 100 mg/ml dextran (M.m. 40 kDa) (Dex40) with 0.7 M Me₂SO in Ham's F12. The ICs were additionally cooled and warmed to different end temperatures (-30, -50, -50 and -196 °C) to determine which temperature intervals contributed most to the IC loss. Then, the cryoprotective action of this serum-/xeno-free medium was investigated in comparison with serum or albumin-containing media by differential scanning calorimetry (DSC) and thermomechanical analysis (TMA). The results showed that the medium based on Dex40 did not decrease the amount of ice formed. However, it could undergo other phase separation and phase transformation to form glassy states. Potential cell-damaging physical processes such as eutectic crystallization/melting, recrystallization of NaCl and/or Me₂SO derivatives, found in serum-containing media and taking place in specific temperature intervals, were not observed in the Dex40 based media. This was in good correlation with indicators of cell survival. Additionally, the application of Dex40 allowed using Me₂SO in lower concentrations (0.7 M) than required for serum-containing media (1.4 M), which may decrease the toxicity of serum-/xeno-free media.

Molecular diversity of the VP2 of Carnivore protoparvovirus 1 (CPV-2) of fecal samples from Bogotá

BACKGROUND

Carnivore protoparvovirus 1, also known as canine parvovirus type 2 (CPV-2), is the main pathogen in hemorrhagic gastroenteritis in dogs, with a high mortality rate. Three subtypes (a, b, c) have been described based on VP2 residue 426, where 2a, 2b, and 2c have asparagine, aspartic acid, and glutamic acid, respectively.

OBJECTIVES

This study examined the presence of CPV-2 variants in the fecal samples of dogs diagnosed with canine parvovirus in Bogotá.

METHODS

Fecal samples were collected from 54 puppies and young dogs (< 1 year) that tested positive for the CPV through rapid antigen test detection between 2014-2018. Molecular screening was developed for VP1 because primers 555 for VP2 do not amplify, it was necessary to design a primer set for VP2 amplification of 982 nt. All samples that were amplified were sequenced by Sanger. Phylogenetics and structural analysis was carried out, focusing on residue 426.

RESULTS

As a result 47 out of 54 samples tested positive for VP1 screening, and 34/47 samples tested positive for VP2 980 primers as subtype 2a (n = 30) or 2b (n = 4); subtype 2c was not detected. All VP2 sequences had the amino acid, T, at 440, and most Colombian sequences showed an S514A substitution, which in the structural modeling is located in an antigenic region, together with the 426 residue.

CONCLUSIONS

The 2c variant was not detected, and these findings suggest that Colombian strains of CPV-2 might be under an antigenic drift.

Recombinant versus bovine hyaluronidase for oocyte denudation before intracytoplasmic sperm injection: a systematic review and meta-analysis

The removal of cumulus cells in a process called oocyte denudation is required in order to visualise, grade and manipulate the oocytes before injection. The objective of this study was to appraise critically the published randomised controlled trials (RCTs) comparing recombinant hyaluronidase with bovine hyaluronidase for oocyte denudation before intracytoplasmic sperm injection (ICSI). We performed a comprehensive literature search of the standard medical databases in order to identify the RCTs comparing oocyte denudation with recombinant hyaluronidase or bovine hyaluronidase before ICSI. Three RCTs involving 2445 oocytes collected from 200 women were analysed. There was substantial heterogeneity among the included RCTs. A meta-analysis from the available moderate to high quality trials found no statistical difference in terms of fertilisation rate, embryo quality and live birth rate between the use of recombinant or bovine hyaluronidase for oocyte denudation before ICSI.IMPACT STATEMENTWhat is already known on this subject? The removal of cumulus cells in a process called oocyte denudation is required in order to visualise, grade and manipulate the oocytes before injection. The long-established source of hyaluronidase has been represented by bovine testes, but concern has been raised regarding the possible negative effects over the fragile oocytes by mechanisms involving low enzyme purity, variable concentrations, trauma, prolonged exposure and integration of external DNA in the oocyte. Recombinant human hyaluronidase has been proposed as an alternative in order to counteract the possible negative effects of using animal derived products.What do the results of this study add? A meta-analysis from the available moderate to high quality trials found no statistical difference in fertilisation rate, embryo quality and live birth rate between the use of recombinant or bovine hyaluronidase for oocyte denudation before ICSI.What are the implications of these findings or clinical practice and/or further research? Future trials should be powered adequately in order to be able to identify the possible small differences between the study groups and they should be conducted according to the CONSORT guidelines as the absence of blinding for outcome assessors can induce detection bias.

Diagnostic Challenges in Canine Parvovirus 2c in Vaccine Failure Cases

In this study, three different diagnostic tests for parvovirus were compared with vaccination status and parvovirus genotype in suspected canine parvovirus cases. Faecal samples from vaccinated (N17) and unvaccinated or unknown vaccination status (N41) dogs that had clinical signs of parvovirus infection were tested using three different assays of antigen tests, conventional and quantitative PCR tests. The genotype of each sample was determined by sequencing. In addition to the suspected parvovirus samples, 21 faecal samples from apparently healthy dogs were tested in three diagnostic tests to evaluate the sensitivity and specificity of the tests. The antigen test was positive in 41.2% of vaccinated dogs and 73.2% of unvaccinated diseased dogs. Conventional PCR and qPCR were positive for canine parvovirus (CPV) in 82.4% of vaccinated dogs and 92.7% of unvaccinated dogs. CPV type-2c (CPV-2c) was detected in 82.75% of dogs (12 vaccinated and 36 unvaccinated dogs), CPV-2b was detected in 5.17% dogs (one vaccinated and two unvaccinated) and CPV-2a in 1.72% vaccinated dog. Mean Ct values in qPCR for vaccinated dogs were higher than the unvaccinated dogs (p = 0.049), suggesting that vaccinated dogs shed less virus, even in clinical forms of CPV. CPV-2c was the dominant subtype infecting dogs in both vaccinated and unvaccinated cases. Faecal antigen testing failed to identify a substantial proportion of CPV-2c infected dogs, likely due to low sensitivity. The faecal samples from apparently healthy dogs (n = 21) showed negative results in all three tests. Negative CPV faecal antigen results should be viewed with caution until they are confirmed by molecular methods.

Evidence of CPV2c introgression into Croatia and novel insights into phylogeny and cell tropism

Canine parvovirus type 2 (CPV2) emerged for the first time in 1978 and evolved into two antigenic variants CPV2a and CPV2b and the third new antigenic variant CPV2c reported in 2000 in Italy. During 2014 unexplained outbreaks of gastroenteritis were observed in kennels where an extensive vaccination program was ongoing and where vaccinated animals showed pathologic lesions consistent with typical parvovirosis. The aim of this study was to investigate whether CPV2 could have played a role in the emergence of these cases and to evaluate genetic or pathological specificities of the virus and the disease. Using PCR and phylogenetic analysis we showed that the CPV2c variant is circulating in Croatia and is in close relationships with isolates from North and South America. Histopathological lesions and cell tropism that are known for CPV2 we are reporting the identification of the virus in glial cells and ovaries. It seems that evolution of CPV and CPV2a-c and adaptation to dogs are two independent events. Croatian isolates had specific and some unique amino acid mutations under positive selection. The effect of the alterations on the immunoglobulin binding cannot be excluded.

Evaluation of a recombination-resistant coronavirus as a broadly applicable, rapidly implementable vaccine platform

Emerging and re-emerging zoonotic viral diseases are major threats to global health, economic stability, and national security. Vaccines are key for reducing coronaviral disease burden; however, the utility of live-attenuated vaccines is limited by risks of reversion or repair. Because of their history of emergence events due to their prevalence in zoonotic pools, designing live-attenuated coronavirus vaccines that can be rapidly and broadly implemented is essential for outbreak preparedness. Here, we show that coronaviruses with completely rewired transcription regulatory networks (TRNs) are effective vaccines against SARS-CoV. The TRN-rewired viruses are attenuated and protect against lethal SARS-CoV challenge. While a 3-nt rewired TRN reverts via second-site mutation upon serial passage, a 7-nt rewired TRN is more stable, suggesting that a more extensively rewired TRN might be essential for avoiding growth selection. In summary, rewiring the TRN is a feasible strategy for limiting reversion in an effective live-attenuated coronavirus vaccine candidate that is potentially portable across the Nidovirales order.

Bovine immunodeficiency virus: a lentiviral infection

The bovine immunodeficiency virus (BIV) is a lentivirus which is known to infect cattle worldwide. Though serological and genomic evidence of BIV in cattle has been found throughout the world, isolation of the virus has been reported only from few places. Very little is known about its impact on animal health status, pathogenesis and mode of transmission. BIV is considered generally non-pathogenic and is not known to cause any serious disease in cattle. BIV is genetically and antigenically related to Jembrana disease virus (JDV), the cause of an acute disease in Bali cattle (Bos javanicus) and human immunodeficiency virus, the cause of acquired immunodeficiency syndrome in human. Therefore, it is important to monitor the presence of BIV in cattle to keep vigil over its possible evolution in its natural host to emerge as pathogenic lentivirus like JDV. Differentiation of BIV infection in cattle from the acutely pathogenic JDV is important for diagnosis of the latter. Currently, BIV is considered as a safe model for understanding the complex genome of lentiviruses. Further research on BIV is indeed needed to elucidate its possible role in animal health as well as for insight into the molecular mechanisms adopted by related lentiviruses.

Development of a novel vaccine against canine parvovirus infection with a clinical isolate of the type 2b strain

Purpose

In spite of an extensive vaccination program, parvoviral infections still pose a major threat to the health of dogs.

Materials and Methods

We isolated a novel canine parvovirus (CPV) strain from a dog with enteritis. Nucleotide and amino acid sequence analysis of the isolate showed that it is a novel type 2b CPV with asparagine at the 426th position and valine at the 555th position in VP2. To develop a vaccine against CPV infection, we passaged the isolate 4 times in A72 cells.

Results

The attenuated isolate conferred complete protection against lethal homologous CPV infection in dogs such that they did not develop any clinical symptoms, and their antibody titers against CPV were significantly high at 7-11 days post infection.

Conclusion

These results suggest that the virus isolate obtained after passaging can be developed as a novel vaccine against paroviral infection.

Embryo Culture Media, Culture Techniques and Embryo Selection: A Tribute to Wesley Kingston Whitten

This review article gives a brief history of the classical experiments that led to the development of the embryo culture medium and in vitro embryo culture. It proposes that, in view of the outstanding and significant pioneering contributions of Wesley Kingston Whitten to the development of embryo culture medium, he be considered the “Father of Embryo Culture Medium”. Furthermore, it describes the nutritional requirements of early embryos and how these requirements with specific references to carbohydrates, amino acids, phosphates, growth factors, etc, have been utilized to formulate increasingly more complex embryo culture media. This has led to the development of progressively more efficacious embryo culture media including the formulation of completely defined and synthetic protein-free embryo culture medium. The review also describes physical factors, growth factors, insemination methods for the fertilization of oocytes and culture methods affecting embryo growth, development, metabolism, oxygen embryotoxicity and survival. In procedural terms, the review also summarizes the evolution of embryo culture techniques from tube culture to, microdrop culture under oil to co-culture to ultra microdrop culture techniques. It includes techniques of in vitro maturation and for the selection of potentially viable embryos of various developmental stages.

The molecular biology of bovine immunodeficiency virus: a comparison with other lentiviruses

Bovine immunodeficiency virus (BIV) was first isolated in 1969 from a cow, R-29, with a wasting syndrome. The virus isolated induced the formation of syncytia in cell cultures and was structurally similar to maedi-visna virus. Twenty years later, it was demonstrated that the bovine R-29 isolate was indeed a lentivirus with striking similarity to the human immunodeficiency virus. Like other lentiviruses, BIV has a complex genomic structure characterized by the presence of several regulatory/accessory genes that encode proteins, some of which are involved in the regulation of virus gene expression. This manuscript aims to review biological and, more particularly, molecular aspects of BIV, with emphasis on regulatory/accessory viral genes/proteins, in comparison with those of other lentiviruses.

Severe acute respiratory syndrome in pregnancy

BACKGROUND

There is limited worldwide experience with severe acute respiratory syndrome (SARS) in pregnancy. We present a case of SARS complicating pregnancy in the third trimester, with outcome data on both the mother and baby.

CASE

A 33-year-old gravida 2 para 1 fulfilling the World Health Organization case definition for probable SARS was admitted to our institution at 31 weeks of gestation with fever, a dry cough, and patchy infiltrates on chest X-ray. The patient was previously healthy and acquired SARS from close contact with an infected family member. Convalescent serology results were positive for antibodies to coronavirus. She stayed in hospital for 21 days and did not require intensive care admission or ventilatory support. Labor occurred spontaneously at term, and a healthy female baby was delivered with no evidence of infection.

CONCLUSION

Severe acute respiratory syndrome in pregnancy is a potentially life-threatening illness with complicated management issues. Hospitalization and care by a multidisciplinary team may optimize chances for a good outcome.

A real-time PCR assay for rapid detection and quantitation of canine parvovirus type 2 in the feces of dogs

We describe a rapid, sensitive and reproducible real-time PCR assay for detecting and quantifying canine parvovirus type 2 (CPV-2) DNA in the feces of dogs with diarrhea. An exogenous internal control was added to control the assay performance from extraction to amplification. The method was demonstrated to be highly specific and sensitive, allowing a precise CPV-2 DNA quantitation over a range of eight orders of magnitude (from 10(2) to 10(9) copies of standard DNA). The reproducibility of the CPV-2 real-time PCR assay was assessed by calculating the coefficients of variation (CV) intra-assay and inter-assay for samples containing amounts of CPV-2 DNA spanning the whole range of the real-time PCR standard curve. Then, fecal specimens from diarrheic dogs were analyzed by hemagglutination (HA), conventional PCR and real-time amplification. Comparison between these different techniques revealed that real-time PCR is more sensitive than HA and conventional gel-based PCR, allowing to detect low viral titers of CPV-2 in infected dogs.

Severe acute respiratory syndrome and dentistry: a retrospective view

Background

Severe acute respiratory syndrome, or SARS, which has created panic in Asia and in some parts of North America, is the first epidemic of the new century. Although it has been well-contained, sporadic cases continue to emerge.

Objectives

The authors trace the emergence of the SARS outbreak from southern China and its spread worldwide, discuss the viral etiology of the infection and its clinical features, and review the infection control guidelines issued during the outbreak by the health authorities in Hong Kong, the Centers for Disease Control and Prevention, the World Health Organization and the American Dental Association. They also review the prospects for a new outbreak and preventive measures.

Overview

The disease, which is caused by a novel coronavirus termed the “SARS coronavirus,” or SARS-CoV, essentially spreads through droplet infection and affects people of any age. It has a mortality rate ranging from 10 to 15 percent. A major hallmark of this disease has been the rate at which it has affected health care workers through nosocomial transmission; in some countries, up to one-fourth to one-third of those infected were in this category. However, no dental health care worker has been affected by SARS in a nosocomial or dental setting.

Conclusions and Clinical Implications

Researchers believe that a combination of factors, including the universal infection control measures that the dental community has implemented and/or the low degree of viral shedding in the prodromal phase of SARS, may have obviated the spread of the disease in dental settings. The dental community should reflect on this outbreak to reinforce the currently applied infection control measures.

Identification of severe acute respiratory syndrome in Canada

BACKGROUND

Severe acute respiratory syndrome (SARS) is a condition of unknown cause that has recently been recognized in patients in Asia, North America, and Europe. This report summarizes the initial epidemiologic findings, clinical description, and diagnostic findings that followed the identification of SARS in Canada.

METHODS

SARS was first identified in Canada in early March 2003. We collected epidemiologic, clinical, and diagnostic data from each of the first 10 cases prospectively as they were identified. Specimens from all cases were sent to local, provincial, national, and international laboratories for studies to identify an etiologic agent.

RESULTS

The patients ranged from 24 to 78 years old; 60 percent were men. Transmission occurred only after close contact. The most common presenting symptoms were fever (in 100 percent of cases) and malaise (in 70 percent), followed by nonproductive cough (in 100 percent) and dyspnea (in 80 percent) associated with infiltrates on chest radiography (in 100 percent). Lymphopenia (in 89 percent of those for whom data were available), elevated lactate dehydrogenase levels (in 80 percent), elevated aspartate aminotransferase levels (in 78 percent), and elevated creatinine kinase levels (in 56 percent) were common. Empirical therapy most commonly included antibiotics, oseltamivir, and intravenous ribavirin. Mechanical ventilation was required in five patients. Three patients died, and five have had clinical improvement. The results of laboratory investigations were negative or not clinically significant except for the amplification of human metapneumovirus from respiratory specimens from five of nine patients and the isolation and amplification of a novel coronavirus from five of nine patients. In four cases both pathogens were isolated.

CONCLUSIONS

SARS is a condition associated with substantial morbidity and mortality. It appears to be of viral origin, with patterns suggesting droplet or contact transmission. The role of human metapneumovirus, a novel coronavirus, or both requires further investigation.

Genetic analysis of canine parvovirus isolates (CPV-2) from dogs in Italy

Genetic and antigenic properties of 62 field isolates of canine parvovirus (CPV-2) collected from 1994 to 2001 in Italy were investigated. Antigenic characterisation was conducted using specific monoclonal antibodies (Mabs). The VP1\VP2 gene was amplified by PCR and characterised with restriction endonucleases to detect the 297 and 265 variant. The VP2 gene of 16 isolates was sequenced and molecular genetic analysis was conducted. The antigenic type prevalent among our isolates is type 2a as well as the 297 variant, which is also prevalent in the rest of Europe. Only the 9.7% of the isolates have the T265P mutation. The VP2 sequences of CPV-2 isolates were very similar to recent Asian isolates. In the threefold spike of CPV-699 a coding change was detected in the 440 residue where threonine was substituted by alanine: the same mutation has been found in two Asian CPV-2 isolates from leopard cats [Virology 278 (2000) 13]. Phylogenetic analysis revealed that the Italian CPV-2 strains followed the same evolution as observed in other countries and they gave no indication of a separate lineage.

Recent developments in the epidemiology of virus diseases

There is continual variation in viral epidemics regarding clinical symptoms, duration and disappearance, and the emergence of new diseases. This can be observed in both human and animal diseases. This evolution of virus diseases is mainly related to three factors: aetiological agent, host and environment. As far as genetic alterations of the virus are concerned, two major mechanisms are involved: mutations such as recombination and reassortment; and selection for resistance or susceptibility. This review focuses on the epidemiology of newly emerged virus diseases in man and animals, such as acquired immunodeficiency syndrome, haemorraghic fevers, bovine spongiform encephalopathy, canine haemorraghic disease and respiratory syndrome in horses.

Canine parvovirus (CPV) vaccination: comparison of neutralizing antibody responses in pups after inoculation with CPV2 or CPV2b modified live virus vaccine

Canine parvovirus type 2 (CPV2) emerged in 1978 as causative agent of a new disease of dogs. New antigenic variants (biotypes), designated CPV2a and CPV2b, became widespread during 1979 to 1980 and 1984, respectively. At the present time the original CPV2 has disappeared in the dog population and has been replaced by the two new viruses. In the present study the comparison of neutralizing antibody titers in two groups of pups (18 pups in each group) inoculated with CPV2 and CPV2b modified live virus vaccines is reported. Using the hemagglutination inhibition (HI) test, relevant differences between antibody titers, against either the homologous or the heterologous virus, were not constantly observed. Using the neutralization (Nt) test, however, the pups inoculated with CPV2 had antibody titers which were approximately 30 times higher to the homologous virus (mean, 4,732) than to the heterologous virus (CPV2b) (mean, 162). The results of these experiments support two conclusions: (i) the HI test may not always accurately evaluate the true immune status of dogs with respect to CPV, and (ii) dogs inoculated with CPV2 vaccine develop relatively low Nt antibody titers against the heterologous virus (CPV2b). These data may suggest an advantage for new vaccines, considering that most presently licensed vaccines are produced with CPV2, which no longer exists in the dog population.

Recent developments in the epidemiology of virus diseases and BSE

There is a continuous change in viral epidemics with respect to clinical symptoms, their duration or disappearance and the emergence of new diseases. This can be observed both in human and animal diseases. This evolution of virus diseases is mainly related to three factors: etiological agent, host and environment. As far as genetic alterations of the virus are concerned, two major mechanisms are involved: 1) mutations such as recombination and reassortment; 2) selection for resistance or susceptibility. The epidemiology of newly emerged virus diseases in man and animals, such as AIDS and hemorrhagic fevers, and bovine spongiform encephalopathy (BSE), canine hemorrhagic gastroenteritis or respiratory syndrome in horses will be discussed.

Formulation of a protein-free medium for human assisted reproduction

The optimal concentrations of individual amino acids, antioxidants, vitamins, osmolytes and energy sources were determined using a 1-cell Swiss outbred (SO) and or F(1) [(CBAxC57BL/6J)xSO] mouse assay in Earle's balanced salt solution containing bovine serum albumin. Based on the findings of these experiments, a number of media were formulated. Of these, the medium showing optimal embryo development and a significantly higher blastocyst hatching rate was investigated further. A protein-free medium (ART-7) was formulated and assessed using 1-, 2- and 4-cell SO mouse embryos. The generation of viable human embryos in the ART-7 series of media in micro- and ultra micro-droplet culture under oil with and without cumulus co-culture following intracytoplasmic sperm injection (ICSI) was investigated. The quality of sibling day 2 human embryos generated in the ART-7 media series was statistically comparable to or better than control embryos. The ART-7 medium was not toxic to human spermatozoa. Fertilization by conventional IVF and subsequent embryo development was not affected. A clinical trial of ICSI-derived embryos generated in the protein-free medium, with and without cumulus co-culture, has resulted in clinical pregnancies (10 of 20 transfers) of which two have proceeded to term, and the remaining patients are in various stages of pregnancy.

Natural selection of the Pol gene of bovine immunodeficiency virus

Genetic variability is a salient feature of lentiviruses, contributing to the pathogenesis of these viruses by enabling them to persist in the host and to resist anti-retroviral treatment. Bovine immunodeficiency virus (BIV), a lentivirus of unknown pathology, infects cattle in the United States and worldwide. Genetic diversity of BIV that is associated with naturally infected cattle is not well studied. We examined the genetic diversity and natural selection of a segment of the BIV pol gene amplified from the leukocyte DNA of naturally infected cattle. A portion of the reverse transcriptase domain (183 bp) of the pol region was targeted for amplification by PCR. PCR products were sequenced directly and aligned. When compared to the sequences of BIV R29-127, a molecular clone of the original BIV R29 isolate, all isolates were greater than 91% identical in nucleotide sequences and 77% identical in amino acid sequences. Pol genotypes were polymorphic at 14% of the nucleotide sites. The ratio of nonsynonymous to synonymous nucleotide substitutions (relative to the number of respective sites, Ka/Ks) was 0.16, indicating that this region of the BIV genome, like that of HIV-1, is subject to purifying selection. Based on the McDonald-Kreitman analysis, this region also was under positive Darwinian selection as HIV-1 and BIV diverged from a common progenitor. Phylogenetic analysis revealed that genotypes were geographically distinct, possibly indicating a common source of infection for animals within a herd.

Use of a medium devoid of any human or animal compound (SMART2) for embryo culture in intracytoplasmic sperm injection

PURPOSE

Our purpose was to evaluate the efficiency of a medium, devoid of any human or animal compound and specially designed for early embryo development (from the zygote to the eight-cell stage), SMART2, in intracytoplasmic sperm injection (ICSI) and to compare it with a medium containing human serum albumin (EllioStep2).

METHODS

Oocytes from 50 ICSI attempts were randomly placed, after sperm injection, into either SMART2 or EllioStep2. After a 48-hr incubation, the embryos were examined for quality scoring before transfer or freezing.

RESULTS

The percentage of normally fertilized oocytes per intact oocytes was slightly higher using SMART2 (139/199 vs. 135/224, respectively, for SMART2 and EllioStep2; P < 0.05). The distribution of embryo scores and the percentage of embryos with a fair morphology (71/143 vs. 72/148, respectively, for SMART2 and EllioStep2; not significant) were identical in both media.

CONCLUSIONS

These data show that SMART2 medium can be successfully used for early embryo growth and, because it is devoid of any human or animal compound, offers better safety for patients than conventional media.

Antigenic characterization of canine parvovirus strains isolated in Italy

28 isolates of canine parvovirus type-2 (CPV-2) were obtained from dogs with hemorrhagic gastroenteritis in Italy. The antigenic structure of CPV-2 isolates was characterized, using four discriminating monoclonal antibodies. In addition, four vaccinal strains were examined. Similar to reports from Australia and the United Kingdom, a much higher prevalence of CPV-2a (25/28 isolates) was observed than the other variant type, CPV-2b (3/28 isolates). DNA fragments (2.2 kbp) of representative strains of CPV-2, CPV-2a and CPV-2b were amplified by the polymerase chain reaction (PCR) and the products were digested by the restriction enzymes (RE) RsaI, HpaII, HindIII and PvuII. The RvaI enzyme allows the differentiation of CPV-2 from CPV-2a and CPV-2b.