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Biomedical subjects

G L Toms

Publications and source records attributed to G L Toms.

9 recordsLinked to original sources
PubMed1977

Behaviour in ferrets of swine influenza virus isolated from man.

After intranasal instillation into ferrets, the "swine" influenza virus A/New Jersey/8/76(Hsw1 N1) had a 50% minimal infectious dose similar to that of previously tested A/PR/8-A/England (H3 N2) recombinants virulent and attenuated for man. A/New Jersey produced only a mild upper respiratory tract infection. However, higher titres of virus were recovered from the lungs over a longer period than experienced previously with Asian and Hong Kong virus strains. There was a diphasic pyrexia the second and higher peaks of which correlated with peak titres of virus in lung macerates. These results suggest that A/New Jersey has a pneumotropic potential in ferrets and, if the animal model is valid, possible in man.

Animals↗
PubMed1977

The pregnant guinea-pig as a model for studying influenza virus infection in utero: infection of foetal tissues in organ culture and in vivo.

Organ cultures of guinea-pig foetal tissues showed a similar pattern of susceptibility to influenza virus to that already observed for human (Rosztoczy et al., 1975) and ferret (Sweet, Toms and Smith, 1977) foetal tissues. Respiratory, alimentary and urogenital tract tissues were susceptible whereas neural and lymphopoietic tissues were insusceptible. However, of the foetal membranes (amnion, chorion, umbilical cord and placenta) only the chorion was susceptible, in contrast to the corresponding ferret tissues, all of which were susceptible. The insusceptibility of the placenta paralleled that of human placenta which is similarly haemomonochorial in structure. Following intracardial inoculation of high titre virus (ca 10(9-4) EBID50) into pregnant guinea-pigs virus was isolated from all foetal membranes (amnion, chorion, umbilical cord and placenta), but in low titre. Although sporadic isolations were made from foetal tissues (intestine, kidney, heart, liver and spleen) there was no evidence for viral replication in these tissues. These results are discussed in relation to possible infection of the human foetus in utero with influenza virus.

Animals↗
PubMed1977

The pregnant ferret as a model for studying the congenital effects of influenza virus infection in utero: infection of foetal tissues in organ culture and in vivo.

Organ cultures of ferret foetal tissues showed a similar pattern of susceptibility to influenza virus to that already observed for human foetal tissues (Rosztoczy et al., 1975); respiratory, alimentary and urogenital tissues supported the replication of influenza virus but nervous and lymphopoietic tissues (those which, in man, are associated with foetal or postnatal abnormalities) were insusceptible. In contrast to corresponding human tissues, ferret foetal placenta and amnion readily supported viral replication although both human and ferret umbilical cord were susceptible. In limited experiments, neither the membranes nor the susceptible foetal tissues became infected after intranasal inoculation of pregnant ferrets of various gestational ages. However, after intracardial inoculation of pregnant ferrets with high titre virus (ca 10(9) EBID50) virus was isolated from both foetal membranes and foetuses. The membranes became infected at early, middle and late gestation, but virus appeared to cross the placental barrier to infect foetal tissues only in late gestation. At this stage virus could be isolated not only from those foetal tissues (respiratory, alimentary and urogenital) susceptible in organ culture, but also in small amounts from tissues which were insusceptible in organ culture (heart, lymphopoietic and nervous tissue). Virus was also isolated from foetal membranes and foetuses of late gestation ferrets following intracardial inoculation with a one hundred-fold lower dose of virus which, unlike the higher dose, did not induce a maternal febrile response. The pregnant ferret appears to be a suitable model for investigating the effects on development of foetal infection with influenza virus but it may have disadvantages with regard to the nature and strength of the placental barrier.

Animals↗
PubMed1975

Replication of influenza virus in organ cultures of human and simian urogenital tissues and human foetal tissues.

A survey of human adult tissues in organ cultures showed that influenza viruses (A/Moscow/1019/65 (h2n2) or a recombinant virus virulent for man (PR/8-A/England/939/69 Clone 7a(H3N2)) could infect uterus, bladder and conjunctiva but not oesophagus under the conditions employed; simian bladder and uterus were also susceptible. These results were similar to those already described for corresponding ferret tissues. Organ cultures of human foetal nasal mucosa, trachea, oesophagus, small and large intestine, and bladder consistently supported replication over 4 days or more with high virus yields. Lung, conjunctiva and umbilical cord were less consistently susceptible and gave lower yields. Placenta and kidney cultures allowed replication of virus in one of 8 and one of 4 experiments respectively, the yields being low and of short duration. Organ cultures of neural tissue (meninges and brain), lymphopoietic tissue (spleen, liver and thymus) and amnion did not support significant viral replication. The results are discussed in relation to possible infection of the foetus in utero with influenza virus.

Animals↗