Oncologist-led BRCA counselling improves access to cancer genetic testing in middle-income Asian country, with no significant impact on psychosocial outcomes

BACKGROUND

Identifying patients with BRCA mutations is clinically important to inform on the potential response to treatment and for risk management of patients and their relatives. However, traditional referral routes may not meet clinical needs, and therefore, mainstreaming cancer genetics has been shown to be effective in some high-income and high health-literacy settings. To date, no study has reported on the feasibility of mainstreaming in low-income and middle-income settings, where the service considerations and health literacy could detrimentally affect the feasibility of mainstreaming.

METHODS

The Mainstreaming Genetic Counselling for Ovarian Cancer Patients (MaGiC) study is a prospective, two-arm observational study comparing oncologist-led and genetics-led counselling. This study included 790 multiethnic patients with ovarian cancer from 23 sites in Malaysia. We compared the impact of different method of delivery of genetic counselling on the uptake of genetic testing and assessed the feasibility, knowledge and satisfaction of patients with ovarian cancer.

RESULTS

Oncologists were satisfied with the mainstreaming experience, with 95% indicating a desire to incorporate testing into their clinical practice. The uptake of genetic testing was similar in the mainstreaming and genetics arm (80% and 79%, respectively). Patient satisfaction was high, whereas decision conflict and psychological impact were low in both arms of the study. Notably, decisional conflict, although lower than threshold, was higher for the mainstreaming group compared with the genetics arm. Overall, 13.5% of patients had a pathogenic variant in BRCA1 or BRCA2, and there was no difference between psychosocial measures for carriers in both arms.

CONCLUSION

The MaGiC study demonstrates that mainstreaming cancer genetics is feasible in low-resource and middle-resource Asian setting and increased coverage for genetic testing.

Evaluation of R-Mix FreshCells in shell vials for detection of respiratory viruses

The performance of a mixture of mink lung and A549 cell lines in shell vials (MSVs) for the detection of respiratory viruses in 159 specimens was evaluated. MSVs, conventional culture, and direct immunofluorescence assay identified 96, 85, and 67% of the influenza A virus-positive specimens, respectively. MSVs provided both a high degree of sensitivity and rapid turnaround times for the detection of influenza A virus.

Use of a single swab in multi-microbe or flex trans transport medium for detection of Chlamydia trachomatis by Roche Amplicor PCR and culture in specimens from two different patient populations

The Roche Amplicor PCR increased the detection of Chlamydia trachomatis compared with culture in promptly processed clinical specimens from a local clinic (100 and 86.5%, respectively) and in samples with delayed processing transported from distant facilities (100 and 72.7%, respectively). A single swab collected in culture transport medium was used. Two media, Multi-Microbe and Flex Trans, were tested and found to be equally acceptable.

Re-examination of the McCoy cell line for confirmation of its mouse origin: karyotyping, electron microscopy and reverse transcriptase assay for endogenous retrovirus

BACKGROUND

The McCoy cell line originally derived from human synovial fluid in 1955, has been later found useful for cultivation of Chlamydia trachomatis. This cell line has been subcultured and exchanged between laboratories for many years. In recent years, the McCoy cell line has been widely used in many clinical diagnostic laboratories and has been supplied through commercial companies for the isolation and identification of Chlamydia trachomatis from clinical specimens.

OBJECTIVES

Since retrovirus-like particles have been observed in McCoy cells and the species of origin of the currently used cell line has not been adequately documented, further characterization of McCoy cell line obtained from commercial sources was carried out.

STUDY DESIGN

This study includes karyotypes analysis using G-banding for the confirmation of species origin of McCoy cells, electron microscopy for examination of virus particles associated with the cells and biochemical assay for reverse transcriptase activity for detection of retrovirus.

RESULTS

Our results showed by karyotype analysis that McCoy cells are of mouse origin. Electron microscopic examination revealed the presence of endogenous retrovirus type-A and type-C virions. Biochemical assays of culture supernatant fluids from McCoy cells detected reverse transcriptase activity which required Mg(2+) ions.

CONCLUSIONS

The present study has confirmed that McCoy cells currently used by many laboratories are mouse cells, not the original McCoy cells derived from human cells. Laboratory workers should be aware of the presence of endogenous murine retrovirus in this cell line and appropriate precautions should be taken.

An adventitious viral contaminant in commercially supplied A549 cells: identification of infectious bovine rhinotracheitis virus and its impact on diagnosis of infection in clinical specimens

The isolation and identification of an adventitious viral agent, infectious bovine rhinotracheitis virus, in one lot of A549 cells from a commercial supplier is described in this report. The presence of infectious bovine rhinotracheitis virus in A549 cells was unexpected and has caused problems in the diagnosis of infections in clinical specimens in three laboratories.

Advantages of multiple cell culture systems for detection of mixed-virus infections

Simultaneous infections by two or more viruses occur frequently, especially in immunosuppressed patients. In order to detect more than one viral agent in a single specimen, multiple cell systems have been employed in our laboratory. Specimens are routinely inoculated into four different cell cultures, namely: MRC-5, a human diploid lung fibroblast cell strain; A549, a human continuous cell line; primary guinea pig embryo (GPE) cell culture, and primary rhesus monkey kidney (RhMK) cell culture. For rapid detection of cytomegalovirus (CMV) antigen, MRC-5 cells grown in shell vials containing coverslips are also inoculated with the same specimens followed by centrifugation. During 1989, nine cases of multiple-virus isolations were obtained in this laboratory. In all nine patients, CMV was detected in MRC-5 cells. Five of the nine cases were co-infected with HSV-1, three were co-infected with adenovirus, and one was co-infected with both HSV-1 and adenovirus. All four adenovirus isolates were obtained in A549 cells. Of the six HSV-1 isolates, one was detected in all three cell cultures, e.g. MRC-5, A549 and GPE; one was detected in both MRC-5 and A549 cells, and four were isolated in a single-cell type only. For nine CMV-positive cases, five were obtained by both conventional and centrifugation cultures, two each were detected by centrifugation or conventional culture only. Thus for a maximum detection of viruses present in a single specimen, it is suggested that multiple-cell-culture systems, together with more than one technique, should be employed.

Activity of (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (HPMPC) against guinea pig cytomegalovirus infection in cultured cells and in guinea pigs

(S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine, HPMPC, and two HPMPC-related nucleoside analogs, (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine, HPMPA, and (2-phosphonylmethoxyethyl)guanine, PMEG, were evaluated for their antiviral activities against guinea pig cytomegalovirus (GPCMV) infection in guinea pig embryo (GPE) cells and human cytomegalovirus (HCMV) infection in human diploid fibroblast (MRC-5) cells. DHPG, 9-(1,3-dihydroxy-2-propoxymethyl)guanine, was used for comparison. The antiviral activity of HPMPC against GPCMV infection in vivo and its toxicity to Hartley guinea pigs were also evaluated. The 50% antiviral effective doses (ED50) of HPMPC, HPMPA, PMEG and DHPG against GPCMV infection in GPE cells were 0.22, 1.4, 0.07 and 62 microM, respectively; and against HCMV infection in MRC-5 cells, the ED50s were 0.51, 0.72, 0.01 and 17.5 microM, respectively. Their cytotoxic doses (CyD50) in GPE replicating cells were 84, 35, 1.4 and 700 microM, respectively and in MRC-5 cells were approximately 114, 31, 0.86 and 750 microM, respectively. Based on their calculated therapeutic indexes, HPMPC was the most potent and selective of the four compounds tested. In vivo, during acute infection, the spleen indexes of all infected animals that were treated with 1.25 to 5.0 mg/kg/day of HPMPC for 5 days were significantly reduced as compared with sham-treated animals. Virus infectivity titers in blood and various tissues of infected animals treated with HPMPC, 2.5 or 1.25 mg/kg/day were not significantly lower than those of the infected, sham-treated animals; with 5 mg/kg/day, infectivity titers in the blood, spleen, and salivary gland were significantly lower in HPMPC-treated than in sham-treated animals. However, HPMPC was toxic to guinea pigs especially at doses of 5 to 10 mg/kg/day. These data showed that HPMPC was highly active and selective in cultured guinea pig cells and human fibroblast cells against CMV infection but did not effectively inhibit GPCMV infection in guinea pigs at minimum toxic concentrations.

Detection of human cytomegalovirus early and late antigen and DNA production in cell culture and the effects of dimethyl sulfoxide, dexamethasone, and DNA inhibitors on early antigen induction

Recently a conventional method for the laboratory diagnosis of human cytomegalovirus (HCMV) infection was improved by using centrifugation culture to enhance viral adsorption and by detecting HCMV early antigen and DNA. Comparison of the sensitivity of three rapid methods using commercial diagnostic reagents for the detection of HCMV early antigen (EA), late antigen (LA), and DNA was quantitatively evaluated in centrifugation cultures of human fibroblast cells (MRC-5) infected with HCMV. HCMV-EA was first detected 4 hours after infection, and the number of antigen-positive cells increased rapidly thereafter. Using biotinylated DNA probe, viral DNA was first detected 12 hours postinfection; the number of DNA-positive cells increased slowly. HCMV-LA was first seen 48 hours postinfection, and the number of LA-positive cells also increased thereafter. Thus detection of HCMV-EA was the most rapid and sensitive method for HCMV diagnosis. Several chemical compounds have been used to enhance HCMV replication. The effect of dimethyl sulfoxide (DMSO), dexamethasone (DEX), 5-bromo-2-deoxyuridine (BrdU), 5-fluoro-deoxyuridine (FdU), and cytosine arabinoside (Ara-C) on HCMV-EA induction was evaluated in centrifugation cultures of MRC-5 cells infected with HCMV. Infected cells treated with 1% DMSO alone or with DMSO plus DEX (10(-5) M) have been shown to increase the number of HCMV-EA-positive cells three- to fivefold over the untreated control cultures. The enhancing effects of Ara-C, BrdU, and BrdU plus FdU were demonstrated only occasionally.

Electron microscopy for the rapid detection and identification of viruses from clinical specimens

The advantages of using electron microscopy for rapid diagnosis of virus infection from clinical specimens, for identification of virus isolates with unusual properties, and for monitoring endogenous agents in cell cultures are illustrated by several actual cases that have occurred over the years. The importance of using morphological characteristics of viruses for initial identification is emphasized.

Replication of human adenoviruses in guinea pig embryo cells: an ultrastructural study

Guinea pig embryo (GPE) cells showed different degrees of susceptibility to human adenovirus types as determined by virus infectivity assay and electron microscopic examination. Adenovirus 2 and 5 induced extensive cellular changes and produced high titers of infectious virus in GPE cells as in human cells. Mature progeny virus and protein crystals were observed in both cell types. Adenovirus 7 induced some cellular changes in GPE cells but only a small number of cells yielded progeny virus as determined by electron microscopy. Adenovirus 3, 8 and 31 induced some cellular changes but no progeny virus was found under electron microscopic examination. Characteristic fibers were observed in nuclei of adenovirus 31 infected cells. The ability of human adenovirus 2 and 5 to replicate in GPE cells is an example of an unusual cross-species biological property of certain adenovirus types. This property may be useful as a biological marker for these virus types.

Disseminated adenovirus infection in an immunocompromised host. Pitfalls in diagnosis

In this report, a bone marrow transplant recipient with rapidly fatal gastroenteritis is presented. The presence of intranuclear inclusions on postmortem light microscopic examination of liver, lung, and small bowel tissue was considered diagnostic of cytomegalovirus infection. However, electron microscopic examination of liver tissue demonstrated adenovirus infection. This was confirmed by isolation of an adenovirus type 2 with unusual laboratory features from liver, lung, colon contents, serum, esophageal swab, and oral ulcerations. Results of a complement fixation test for antibodies to adenovirus performed on postmortem serum samples were negative, and a titer of 1:4 was noted for antibody against cytomegalovirus. This case illustrates the diagnostic pitfalls that may be encountered in establishing a specific viral diagnosis in severely ill patients.

Comparison of fluorescent-antibody-to-membrane-antigen test, indirect immunofluorescence assay, and a commercial enzyme-linked immunosorbent assay for determination of antibody to varicella-zoster virus

The demand for sensitive and specific assays to determine immune status to varicella can be expected to increase with the anticipated availability of a varicella-zoster virus vaccine for use in nonimmune adults, especially health care personnel, and in immunosuppressed children. Although the fluorescent-antibody-to-membrane-antigen (FAMA) test remains the reference standard to which other tests are compared, simpler alternative assays are needed. In this study, the FAMA was compared with a simple indirect immunofluorescence assay (IFA) and a commercially available enzyme-linked immunosorbent assay (ELISA) for the detection of antibody to varicella-zoster virus. One hundred and twelve serum samples were screened by the FAMA test and IFA at a 1:5 dilution, and 100% agreement was found. Of these samples, 101 were available for testing by ELISA, and identical results were obtained with 97 samples (96% agreement). When the samples were screened at a 1:2 dilution, 99 of 101 results agreed. In addition, 31 spinal fluid samples were tested by all three methods. When screening was at a 1:2 dilution, there was 96.8% agreement between the FAMA test and IFA. When the cutoff value established for sera was used for the spinal fluid samples, there was 90.3% agreement between the ELISA and the FAMA test. Thus, both IFA and ELISA can be considered sensitive and specific alternatives to the FAMA test, and in addition, both use commercially available reagents.

Antiviral effect of 9-(1,3-dihydroxy-2-propoxymethyl)guanine against cytomegalovirus infection in a guinea pig model

The antiviral activity of 9-(1,3-dihydroxy-2-propoxymethyl)guanine (DHPG) against guinea pig cytomegalovirus (GPCMV) was evaluated in guinea pig cell cultures and in Hartley guinea pigs. The 50% effective dose of DHPG against GPCMV replication in cell cultures was 71 microM. Ultrastructural studies revealed that DHPG inhibited the formation of viral cores and the production of nucleocapsids, enveloped virions and dense bodies, but the drug did not prevent the formation of virus induced intranuclear tubular structures. In vivo, guinea pigs inoculated intraperitoneally with GPCMV were treated with DHPG, 25 mg/kg subcutaneously, twice daily. Treatment was initiated 24 h after infection and continued for 7 days. During the acute infection, the average body weights of DHPG-treated, virus infected guinea pigs were approximately 14% lower than the sham-treated counterparts on day 10, 11 and 13 post-virus inoculation. Virus infectivity titers were higher in the lungs of DHPG-treated guinea pigs on day 10 than the sham-treated ones. Although there was no significant difference on histopathologic lesions in the spleen, liver and lungs of the drug-treated and the sham-treated guinea pigs, DHPG treated animals appeared to have fewer virus-induced lesions or inclusions in the kidneys and salivary glands than the sham-treated ones. In addition, virus infectivity titers in the salivary gland of DHPG treated guinea pigs were consistently lower than the sham-treated animals.

Illegal abortion: an attempt to assess its cost to the health services and its incidence in the community

This article describes a study designed to test a method for assessing the cost to the health services of illegally induced abortion and the feasibility of estimating the incidence of induced abortion by a field interviewing approach. The participating centers included three hospitals in Ankara, Turkey; three hospitals in Ibadan, Nigeria; one hospital in Caracas and one in Valencia, Venezuela; and two hospitals in Kuala Lumpur, Malaysia. Hospitalized abortion cases were classified as induced or spontaneous or as "probably induced," "possibly induced," or "unknown" according to a classification scheme comprising certain medical criteria. The sociodemographic characteristics of induced and spontaneous abortion cases were subjected to discriminant function analysis and the discriminating variables best characterizing the induced versus the spontaneous abortion groups were identified for each center. On the basis of this analysis, the "probably" and "possibly" induced and "unknown" categories were further classified as induced or spontaneous abortion, with stated probabilities. Thus an overall estimate is made of the proportion of all hospitalized abortions that can be considered illegally induced outside the hospital. Selected results on costs of induced and spontaneous abortion are shown. The method further tested the feasibility of obtaining valid survey data on abortion from the communities studied by re-interviewing the women hospitalized for induced and spontaneous abortion six months later in their homes. This exercise showed a degree of under-reporting of abortion that varied widely among centers, even among women who had admitted illegal induction at the time of hospitalization. The feasibility of estimating the incidence of illegal abortion by field studies is discussed in the light of these findings.

Nucleic acid hybridization in the diagnosis of viral infections

Recombinant DNA technology, including molecular cloning and nucleic acid hybridization, is now being applied to problems in clinical virology. Although viral isolation in cell culture remains the most sensitive and specific diagnostic test for many viruses, for some viruses, isolation in cell culture is lengthy or difficult or has not yet been achieved. Utilization of hybridization techniques has already resulted in important new information concerning the pathogenesis of a number of viruses, such as Epstein-Barr virus, hepatitis B virus, and human papillomavirus. In addition, time to diagnosis for viruses such as cytomegalovirus, Epstein-Barr virus, and varicella-zoster virus can be significantly shortened to 36 to 48 hours, a great improvement over standard isolation with obvious importance for patient management. Hybridization techniques have also been applied to screening of antiviral agents. Although results of studies to date have been encouraging, significant problems remain to be solved before these techniques can be applied in a routine diagnostic laboratory. First, more sensitive assays must be developed. One approach is the generation of probes with higher specific activities. Synthesis of single-stranded probes using recombinant M13 bacteriophage as a template results in probes of higher specific activities that also cannot re-anneal to themselves because they are not complementary. Thus, more probe is available to anneal to sample DNA. Synthesis of cRNA probes that form more stable hybrids with DNA is another approach that is receiving attention. A second problem is reagent safety and stability. The most sensitive and commonly used label in the studies reviewed in this article has been 32P. With its half-life of 2 weeks, potential hazards to personnel, and disposal problems, it is probably not suitable for clinical laboratories. A major step in the development of nonradioactive, stable probes has been synthesis of biotinylated nucleotide analogues that can be efficiently incorporated into DNA or RNA. Biotinylated probes are stable for 1 to 2 years at -20 degrees C, and their use obviates the need for autoradiography, thus shortening reaction times. In addition, very high concentrations of probes can be used without the background problems encountered with radiolabels. To date, biotinylated probes have been significantly less sensitive than those labeled with 32P, but continued efforts to improve sensitivity have yielded promising results.(ABSTRACT TRUNCATED AT 400 WORDS)

Antiviral activity of CP-20,961 against herpes simplex viruses in vitro

The antiherpesvirus activity of CP-20,961 [N,N-dioctadecyl-N',N'-bis (2-hydroxyethyl) propanediamine, or Avridine] was investigated in cultured guinea pig embryo (GPE) cells. Plaque formation of herpes simplex virus type 1 (HSV1) and type 2 (HSV2) was inhibited, but vesicular stomatitis virus replication was not inhibited, in GPE cells treated with CP-20,961 before infection. The ID50 concentration of CP-20,961 for HSV was about 50 micrograms/ml for 3-4 days of pretreatment. After virus adsorption and penetration, the same concentration of CP-20,961 had no effect on HSV plaque formation. The compound showed no detergent-like properties nor did it elicit any detectable interferon activity. Thus, the anti-HSV activity of CP-20,961 appeared to be associated with blocking the adsorption or penetration of the virus or both.

Distinctive characteristics of crude interferon from virus-infected guinea-pig embryo fibroblasts

Crude interferon preparations from primary guinea-pig embryo cells infected with vesicular stomatitis virus strain T1026R1 were shown to be more sensitive to heat (37 degrees C), pH 2.0, and SDS than crude mouse interferon. Since the proportion of antiviral activity lost after each treatment was nearly the same, the existence of a single fraction of antiviral activity sensitive to all three treatments was suggested. Support for this possibility was given by the finding that subjecting this guinea-pig interferon to any one of the treatments rendered it insensitive to the effects of the other two.

Histopathologic and ultrastructural studies of disseminated cytomegalovirus infection in strain 2 guinea pigs

Inbred strain 2 guinea pigs developed severe disseminated disease during acute experimental guinea pig cytomegalovirus (GPCMV) infection. A high mortality rate (100%) resulted, with most animals dying between 10 and 14 days after high dose (7.5 X 10(5) TCID50) virus inoculation. Infectious virus was recovered from many tissues, including spleen, lungs, liver, pancreas, heart, adrenals, kidneys, and salivary glands. The rate of GPCMV isolation from these tissues ranged from 50 to 100%. Gross lesions were observed in the spleen, liver, and lungs. On histologic examination, lesions were also seen in many other organs, including heart, pancreas, kidneys, adrenals, brain, intestines, and salivary glands. Intranuclear viral inclusions were present in many cell types of various organs. Under electron microscopic examination, cells with viral inclusions were easily found in the spleen, and liver, but less readily in the lungs, kidneys, salivary glands, and other organs. Most of the intranuclear inclusions consisted of electron-dense fibrils (10 nm diameter), viral nucleocapsids (100 nm), and tubular structures (60 nm diameter). Dense bodies and enveloped dense virions containing single or multiple capsids were present in the cytoplasm of many infected cells. The morphologic developments of GPCMV in these visceral tissues of strain 2 guinea pigs resembled those seen in GPCMV-infected cultured guinea pig cells but differed from those observed in the infected salivary gland duct cells. Strain 2 guinea pigs are a useful animal model for studying disseminated infection in CMV-associated human diseases.

Detection of viral genomes in cultured cells and paraffin-embedded tissue sections using biotin-labeled hybridization probes

A method of in situ cytohybridization is described for the detection of specific viral genomes in infected cell cultures or paraffin-embedded tissue sections without the use of radioisotopes. Biotin-labeled analogs of TTP are incorporated into viral DNA in vitro by nick translation and the resultant DNA probes hybridized to cytologic samples. Cells containing viral genetic material are then revealed by standard immunofluorescence, immunoperoxidase, or affinity cytochemical techniques that are based on the specific interaction between biotin and antibiotin IgG or avidin. Hybridization probes containing nucleotides that have an 11- or 16-atom spacer arm between the biotin molecule and the pyrimidine ring interact with these detector proteins more efficiently than probes containing biotin-nucleotides with a 4-atom spacer arm. The total procedure can be performed fairly rapidly (24 hr or less) and numerous samples can be processed simultaneously. Although the detection methods employed to date are not as sensitive as autoradiographic procedures with high specific activity probes, more sensitive protein detector complexes are currently being constructed. The speed, specificity, and resolving power of this technique should be of general utility in screening for the presence of infectious agents in cell or tissue samples. Here we report the visualization of parvovirus, polyomavirus, herpes simplex virus, adenovirus, and retrovirus genetic material in infected cell cultures and herpes simplex and adenovirus DNA in paraffin-embedded autopsy tissues.

Cytomegaloviral infections in the guinea pig: experimental models for human disease

The salivary gland virus of guinea pigs, or guinea pig cytomegalovirus (CMV), was first described in The Journal of Infectious Diseases in 1920. Early studies were concerned with the nature of intranuclear and intracytoplasmic inclusions, viral pathogenicity, transmissibility in animals, and similarity to human viral infections. Subsequently, tissue culture techniques and electron microscopy of guinea pig CMV-infected salivary gland and tissue culture cells demonstrated the morphogenesis which closely resembles that of human CMV. By use of tissue culture cocultivation techniques, generalized viremic infection, transplacental transmission of virus, congenital infection, CMV-associated mononucleosis, interstitial pneumonia, and transmission of virus by blood transfusion have been demonstrated. In studies of live attenuated and noninfectious envelope antigen vaccines for the prevention of transplacental transmission of virus and of interstitial pneumonia, the guinea pig model has demonstrated efficacy of such vaccines under experimental conditions. Investigations of polymorphonuclear leukocyte function during primary CMV infections may elucidate mechanisms for bacterial, parasitic, and fungal superinfections in human disease.

Improved conditions for the production and detection of interferon from guinea pig embryo cells

Primary guinea pig embryo (GPE) fibroblasts were assessed as potential sources of guinea pig interferon (IFN). GPE cells proved to be excellent in vitro producers of guinea pig IFN, although the actual amounts produced were only detectable when sample irradiation under ultraviolet light (to inactivate inducing viruses) was substituted for overnight sample treatment at pH 2. Thus, the rapid spontaneous inactivation of large proportion of the antiviral activity after overnight exposure to 4 degrees C, regardless of pH, was avoided. IFN was induced using Newcastle disease virus (NDV), Sindbis virus, and a genetic variant of vesicular stomatitis virus, VSV T1026R1. Each virus exhibited different dose response kinetics, with VSV T1026R1 proving the most efficient inducer of the three. Optimal IFN production depended largely on virus multiplicity and cell age. All the antiviral activity produced by GPE fibroblasts had the classical properties of species specificity, susceptibility to trypsin, and a broad range of antiviral activity.

Ultrastructural localization of viral antigen in nuclear inclusions of cytomegalovirus infected guinea pig cells

Intranuclear localization of viral antigens in guinea pig cytomegalovirus (GPCMV) infected guinea pig embryo (GPE) cells was investigated by cross-reactive indirect immunoperoxidase and immunoferritin techniques utilizing guinea pig antisera to GPCMV. Following primary fixation with 4 percent paraformaldehyde, a brief treatment of infected cells with 0.25 percent trypsin was found to enhance penetration of antibodies and the conjugates. Ferritin or horseradish peroxidase conjugated goat anti-rabbit IgG was used as a secondary antibody that cross reacted with guinea pig immunoglobulins in order to reduce non-specific immunochemical reactions. Using light microscopy following immunoperoxidase staining, GPCMV antigens in an intranuclear location were not discernable when the infected cells were stained without pretreatment with trypsin, however intranuclear GPCMV antigens could be visualized after the fixed cells were treated with trypsin for 2-4 minutes prior to addition of the antiserum. Electron microscopic examination following indirect immunoferritin staining revealed viral antigens localized on viral capsids and on scattered electrondense amorphous matrices but not on the surrounding tubular structures on fibrils. The possibility that tubular structures may be a host cell product produced in response to GPCMV infection is discussed.

Ultrastructural localization of cytomegalovirus DNA synthesis in infected guinea-pig cells

Using electron microscopic autoradiographic techniques, the uptake of [methyl-3H] thymidine into uninfected and guinea-pig cytomegalovirus (GPCMV)-infected guinea-pig embryo (GPE) fibroblast cells was investigated. In GPCMV-infected GPE cells, [methyl-3H]thymidine uptake into cellular DNA was inhibited prior to the onset of virus DNA synthesis as well as during the entire period of virus replication. Virus DNA synthesis increased slowly during the period of active virus replication, which usually lasted from 18 to 48 h post-infection. Only the electron-dense amorphous matrices and fibrillar structures in the nuclear inclusions were associated with the tritiated labels and thus contained virus DNA.

Effects of vaccination on cytomegalovirus-associated interstitial pneumonia in strain 2 guinea pigs

The pathogenesis and prevention of generalized infection and interstitial pneumonia due to cytomegalovirus (CMV) in inbred strain 2 guinea pigs were investigated. Eighteen animals inoculated with approximately 10(7) 50% tissue culture infective doses of virulent salivary gland-passaged guinea pig CMV (GPCMV-SG) developed generalized, viremic CMV infections, and 44% of the animals died. Most (68%) cocultivated tissues showed CMV infection, including lungs, which demonstrated severe bilateral interstitial pneumonia. Guinea pigs inoculated with live tissue culture-passaged GPCMV (GPCMV-TC) vaccine developed mild, nonlethal, generalized CMV infections and minimal histopathologic changes in infected tissues, including lungs. After challenge of 19 GPCMV-TC-vaccinated animals with GPCMV-SG, viremia was detectable in two (11%); CMV was detected in 15% of cocultivated tissues and rarely in lungs. Although vaccinated animals showed histologic evidence of interstitial pneumonia after challenge, none died. Strain 2 guinea pigs are useful for studies of pathogenesis and prevention of generalized CMV infection, particularly CMV-associated interstitial pneumonia.

Use of guinea pig embryo cell cultures for isolation and propagation of group A coxsackieviruses

The isolation of group A coxsackieviruses from clinical specimens generally requires the use of suckling mice. By using guinea pig embryo cells, the following coxsackieviruses were isolated from throat swabs and stool samples obtained from patients with a variety of illnesses: two of type A2, one each of types A6 and A8, and four of type 10. Distinct cytopathic effects were produced in 3 to 5 days in the guinea pig embryo cells inoculated with the clinical specimens. In addition, a number of prototype group A coxsackieviruses, including types 2--6, 8, 10, and 12, were readily propagated in guinea pig embryo cell cultures. Thus, guinea pig embryo cells appeared to be a sensitive alternative cell culture system for the isolation and propagation of certain types of group A coxsackieviruses.

Pattern of acute pelvic inflammatory disease in abortion-related admissions

We evaluated 3,066 consecutive women admitted during 1 year to two major hospitals of Kuala Lumpur and the adjacent urban area of Malaysia. Indicators of acute pelvic inflammatory disease were more common among patients with induced abortions. PID was thought to be a major contributor to the higher costs associated with management of patients with induced abortions.

New endogenous herpesvirus of guinea pigs: biological and molecular characterization

Two known guinea pig herpesviruses, guinea pig cytomegalovirus (GPCMV) and guinea pig herpes-like virus (GPHLV), and well characterized. A third herpesvirus (GPXV) was originally isolated from leukocytes of healthy strain 2 guinea pigs. Growth of GPXV in guinea pig embryo fibroblastic cells produced a characteristic cytopathic effect. Electron microscopy of guinea pig cells infected with GPXV revealed the morphological development of a herpesvirus. Cross-neutralization tests and immunoferritin electron microscopy demonstrated that GPXV, GPCMV, and GPHLV were serologically distinct herpeviruses of guinea pigs. To confirm the distinction between these three herpesviruses, DNA genomes were compared by CsCl equilibrium buoyant density measurements and restriction endonuclease cleavage analysis. 32P-labeled viral DNA ws obtained from nucleocapsids isolated from virus-infected cells, and the buoyant density of GPXV DNA differed from that of GPCMV and GPHLV. Cleavage of viral DNAs with restriction endonucleases followed by gel electrophoresis revealed distinct patterns for each virus.

Viruses of guinea pigs: considerations for biomedical research

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Western equine encephalitis mimicking herpes simplex encephalitis

A patient with severe encephalitis had focal findings suggesting herpes simplex encephalitis. After brain biopsy and administration of vidarabine, the patient's condition improved but was ultimately diagnosed as a case of western equine encephalitis. Further complicating laboratory diagnosis, an endogenous murine coronavirus was isolated from newborn mice inoculated with the patient's brain biopsy tissue. This case illustrates the need for caution in attributing therapeutic responses to antiviral agents or in attributing human illness to viruses that are actually endogenous to animals and tissue culture used in diagnostic virology.

Ultrastructural development and persistence of guinea pig cytomegalovirus in duet cells of guinea pig submaxillary gland

Salivary glands from Hartley guinea pigs were experimentally infected with guinea pig cytomegalovirus (GPCMV) and examined by light and electron microscopy at different time intervals. Characteristic intranuclear and intracytoplasmic viral inclusions were observed in duct cells of infected animals. Viral inclusion counts and infectivity titers in the salivary gland reached maximum levels by 3 to 4 weeks after infection; infectivity persisted, though at reduced levels, for at least 30 weeks. Electron microscopic examination of viral inclusions revealed several developmental events including nucleocapsid assembly, envelopment of nucleocapsids at the inner nuclear membrane and their enclosure by a thin vacuolar membrane. While contained within cytoplasmic vacuoles, enveloped virions acquired surface spikes. Cytoplasmic vacuoles containing virions subsequently coalesced and discharged mature virions at the cell surface into the lumen of the salivary gland duct. The data indicate that the ultrastructural development of GPCMV in the guinea pig salivary gland shows many similarities to that of human cytomegalovirus in humans. The salivary gland may provide a primary locus for virus shedding and horizontal transmission of cytomegalovirus.

Ultrastructural development of guinea pig cytomegalovirus in cultured guinea pig embryo cells

The ultrastructural development of guinea pig cytomegalovirus (GPCMV) in guinea pig embryo cells was studied using electron microscopy. Tubular structures were found in nuclei of virus infected cells, followed by the appearance of intranuclear inclusions containing virus nucleocapsids. While some nucleocapsids were enveloped at the inner nuclear membrane, others were released into the cytoplasm where they were associated with, or within, dense matrix which was subsequently enveloped by cytoplasmic membranes to form enveloped dense virions. Dense bodies without virus capsids were formed in the cytoplasm and enveloped in a similar manner. An involvement of the nuclear pores in the release of unenveloped virus capsids from the nucleus to the cytoplasm was postulated. Evidence that the enveloped dense virions and dense bodies shared common envelope antigen(s) was obtained by immunoelectron microscopy. The similarities and differences in the ultrastructural development of GPCMV and other cytomegaloviruses are discussed.

Induction of tumors by a guinea pig herpesvirus-transformed hamster cell line

Syrian hamster embryo cells that had been transformed in vitro by guinea pig herpes-like virus (GPHLV) were found to be oncogenic when inoculated into hamster sc or ip. Of 71 animals inoculated, 30 showed tumors at the site of inoculation. Tumors appeared 4-23 weeks after inoculation of the transformed cells at passage 37 or higher. Inbred and randombred hamsters of all ages were susceptible. Upon microscopic examination the tumors were characterized as fibrosarcomas. The cultured hamster tumor cells were easily transplanted into hamsters, but produced no evidence of tumors when inoculated into guinea pigs. Infectious GPHLV was not isolated from the tumor cells, but GPHLV-specific surface antigens were detected in tumor cells by immunofluorescence of GPHLV antiserum produced in rabbits. Sera from tumor-bearing hamsters did not contain GPHLV-neutralizing antibodies, but sera from 4 of 23 hamsters bearing primary tumors and 12 of 41 bearing transplanted tumors produced nuclear fluorescence in cells infected with GPHLV, thus establishing the relationship between the guinea pig herpesvirus and the hamster tumors.

Comparison of guinea pig cytomegalovirus and guinea pig herpes-like virus: growth characteristics and antigentic relationship

The growth characteristics of guinea pig cytomegalovirus (GPCMV) and guinea pig herpes-like virus (GPHLV) in cell cultures were compared. Guinea pig fibroblast cells were highly susceptible to infection with both viruses, whereas guinea pig kidney cells were sensitive only to GPHLV. No cytopathic effect was observed in the latter cell system after infection with GPCMV,nor was there an increase in virus titer, although the cirus persisted in the kidney cells for 2 to 3 weeks postinfection. Electron microscope studies showed nonvirion tubular structures in GPCMV -infected fibroblast cells, but not in GPHLV- infected cells. Large packages of enveloped nuclear virus particles were commonly seen in GPHLV -infected cells, especially kidney epithelial cells, but none were found in the GPCMV -infected fibroblasts. Complete enveloped extracellular virus particles were present in both virus-cell systems. Both viruses showed narrow host spectra and replicated well only in guinea pig cells although GPHLV multiplied to some degree in rabbit cells. No antigenic relationship could be demonstrated between the two viruses using antisera specific for each virus that was produced in rabbits and guinea pigs. Rabbits produced high neutralizing antibody titers to GPHLV, whereas guinea pigs were the animals of choice for GPCMV antiserum production.

Use of electron microscopy for detection of viral and other microbial contaminants in bovine sera

A total of 25 lots of bovine serum samples were pelleted in Beem capsules for thin sectioning and were examined by electron microscopy. These included 17 lots of fetal bovine serum pools and five lots of calf serum pools obtained from commercial sources, and three lots of adult bovine serum from local dairy farms. Virus-like particles, 50 to 300 nm in diameter, were detected in 17 of 25 (68%) of the sera. Five of 25 serum samples showed the presence of mycoplasma-like agents. Incubation of bovine serum at 35 C for 1 or 2 weeks appeared to destroy some of these agents, but in certain instances it enhanced bacteria and bacteriophage contaminants. The advantages of electron microscopy using the thin-sectioning technique for detection of microbial contamination in bovine sera are illustrated.

Methods for the detection of viruses in bovine serum

An evaluation of selected commonly used procedures for the recovery of endogenous viral contaminants in bovine serum was undertaken. Low speen centrifugation (25,000 x g) was found to be efficient for the recovery of bovine herpesvirus type 1 (BHV-1) and parainfluenza virus type 3(PI-3) in bovine serum. Decreased infectivity titers were obtained when parainfluenza virus type 3, and to a lesser extent bovine herpes virus type 1, were concentrated using high speed centrifugation (100,000 x g) for extended time periods. In neither case could infectious virus be recovered from serum containing sufficient titers of homologous neutralizing antibody, although electron microscopy examination revealed the presence of the viruses previously added. In the presence of homologous antibody, virus particles appeared to have a diffuse, poorly defined outer membrane. Neutralizing antibody titers to bovine herpesvirus type 1 and outer membrane. Neutralizing antibody titers to bovine herpesvirus type 1 and parainfluenza virus types were found in fetal, calf, and adult bovine sera. The prevalence and magnitude of the antibody titers to these viruses increased with the age of the animals examined.

Development of an equine herpesvirus in two cell culture systems: light and electron microscopy

Development of equine herpesvirus strain 82A was studied in cells from primary horse kidney (HOK) cultures and an equine dermis (ED) cell strain. HOK and ED cells are equally susceptible to the 82A virus infection and yield about the same amount of infectious virus. Intranuclear inclusions were present in both cell systems, but a ring-shaped syncytial formation was observed only in infected ED cells. Ultrastructural studies revealed the presence of dense granules 30 nm in diameter and characteristic star-like clusters of granules in the infected HOK cells, but these granules were rarely seen in the infected ED cells. Viral nucleocapsids were associated with homogenous nuclear matrices, with moderate electron density in both cell systems. Viral nucleocapsids acquired envelopes by budding into the nuclear vacuoles in both HOK and ED cells. Budding from inner nuclear membranes into perinuclear cisterna or into cytoplasmic vacuoles also was observed frequently in HOK cells but was not seen often in infected ED cells. Multiple, membrane-bound intranuclear inclusions of fibrillar material which may be associated with virus envelopes were seen only in infected ED cells. Enveloped virus particles seen in nuclear vacuoles or perinuclear cisterna were more regular in shape and had a 130-nm diameter, whereas the enveloped virus particles seen in the cytoplasm and extracellular space were more irregular in shape and had a 130- to 160-nm diameter.