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Biomedical subjects

A A Codd

Publications and source records attributed to A A Codd.

35 records · Page 2Linked to original sources
PubMed1979

Viruses and acute abdominal pain in childhood.

Children aged at least 4 years admitted to hospital with acute abdominal pain, excluding appendicitis, were investigated for the presence of viruses. Out of 181 children 29 were found with viruses of whom 18 had nonspecific abdominal pain. Eight others were found to have virus-like particles on electron microscopical examination of their faeces. Virus infections contribute to a small extent to nonspecific abdominal pain in childhood, but in many cases the cause remains unknown.

Abdomen, Acute↗
PubMed1979

Herpes simplex virus uveitis and optic neuropathy. An experimental investigation.

The sequence of events which follows the intravitreal injection of herpes simplex virus (HSV) into one eye has been observed as it affects the eyes, optic nerves, and optic chiasm. Initially the injected (right) eye showed an intense iridocyclitis and about 16 days after inoculation an exudative retinal detachment was observed. A similar sequence of events occurred in the uninjected (left) eye about 6 days later. HSV has been shown to pass along the right optic nerve towards the chiasm and from there down the left optic nerve. The primary route of spread appears to be via neuroglial cells rather than the axons. Tissue necrosis and re-myelination have been observed.

Animals↗
PubMed1977

Inhibition of phagocytosis in vitro by obligate anaerobes.

A variety of species of obligate anaerobes have been shown to interfere with the phagocytosis and killing of Proteus mirabilis and other aerobic bacteria in vitro. Although all the obligate anaerobes examined showed this activity, the effect was greatest with strains of Bacteroides melaninogenicus and B. fragilis. In contrast, none of the 36 aerobes tested acted in this way. These observations suggest that the presence of obligate anaerobes may be fundamental to the pathogenesis of some types of infections.

Bacteroides↗
PubMed1976

Epidemic of echovirus 19 in the north-east of England.

We report the first large-scale outbreak of echovirus 19 infection. It occurred in the north-east of England during the summer and autumn of 1974. The virus was isolated from 268 patients in the region. The infection spread from the urban to more rural areas, reaching a peak in mid-August. Males were affected more often than females in the ratio 1-6:1. Half of the patients were under eight years of age, relatively few were over 35 years. Aseptic meningitis and upper respiratory infections were the commonest presentations, though a wide range of other diseases occurred including gastroenteritis, myalgia, pericarditis, undifferentiated pyrexia, rashes and a syndrome analagous to bacteraemic shock. There was no evidence that the pattern or severity of the disease changed during the outbreak. Infants under the age of six months were more seriously affected than older children and adults. All patients except one made an uneventful recovery. Of the routine tissue culture cells HEp2 and HeLa were by far the most satisfactory for virus isolation.

Adolescent↗
PubMed1970

The effect of carbon dioxide on the sensitivity of Bacteroides fragilis to certain antibiotics in vitro.

The effect of 10% carbon dioxide on the sensitivity to four antibiotics of 10 strains of Bacteroides fragilis was studied. The minimum inhibitory concentrations of erythromycin and lincomycin hydrochloride for these strains were four to 32 times higher, when grown in hydrogen plus 10% carbon dioxide, than the values obtained when the strains were grown in pure hydrogen. A similar effect was obtained by growing the strains in hydrogen on an acid medium. Except for Haemophilus influenzae and Clostridium tertium the sensitivity to erythromycin and lincomycin hydrochloride of other species of bacteria examined was not affected by the atmosphere in which the tests were carried out. 7-Chlorolincomycin and rifamycin B diethylamide, to which the strains of B. fragilis were uniformly sensitive, were not significantly affected by additional carbon dioxide. The possible mechanisms underlying this phenomenon and its clinical implications are discussed, and a case report describing the successful use of erythromycin in the treatment of a cerebral abscess due to B. fragilis is presented. In a recent study in this laboratory of the sensitivity to antibiotics of B. fragilis the majority of strains were found to be inhibited by 0.15 mug/ml of erythromycin and by 0.55 mug/ml of lincomycin hydrochloride (Ingham, Selkon, Codd, and Hale, 1968). After this work had been completed hydrogen plus 10% carbon dioxide was substituted for pure hydrogen in the anaerobic technique. Strains of B. fragilis isolated on routine culture now appeared to be relatively resistant to erythromycin and lincomycin hydrochloride when their sensitivity was examined by the disc diffusion method. A more detailed investigation of this phenomenon was carried out, the results of which are reported here. The opportunity was also taken to examine the susceptibility of B. fragilis to two new antibiotics, namely, 7-chlorolincomycin and rifamycin B diethylamide.

Anti-Bacterial Agents↗
PubMed1968

A study in vitro of the sensitivity to antibiotics of Bacteroides fragilis.

During a two-year period of observation Bacteroides species were isolated from specimens of pus and vaginal swabs from 115 patients in this hospital. Thirty-five representative strains proved on examination to be Bacteroides fragilis. Minimal inhibitory and minimal bactericidal concentrations of six antibiotics for these strains were determined. All strains were resistant to streptomycin, neomycin, and polymyxin, slightly sensitive to penicillin and ampicillin, and fully sensitive to tetracycline, chloramphenicol, erythromycin, and lincomycin. The minimum bactericidal concentrations of chloramphenicol, erythromycin, and lincomycin were two to four times the minimal inhibitory concentrations. Tetracycline failed to exert any consistent bactericidal effect.The treatment of patients with infections caused by B. fragilis is discussed in the light of the findings in vitro.

Anti-Bacterial Agents↗
PubMedDate not supplied

The pathogenesis and pathway into the central nervous system after intraocular infection of herpes simplex virus type I in rabbits.

Herpes simplex virus (HSV) type I was injected into the right eye of 18-day-old New Zealand albino rabbits and the animals were killed on the fourth and eighth days after inoculation. Longitudinal section of the optic nerves and chiasma showed that both myelinated axons and neuroglial cells crossed at the chiasma. Semi-serial (1 micrometer) and ultrathin sections showed the presence of HSV in both astrocytes and oligodendrocytes, although no particles were seen in the myelinated axons; the infected cells were confined to the medial side of the right optic nerve. HSV travels centropetally along the optic pathway and slowly spreads laterally by cell-to-cell infection. The virus does not appear to kill the astrocytes and oligodendrocytes, and also does not directly damage the myelin sheath.

Animals↗
PubMedDate not supplied

Progression of herpes encephalitis in rabbits following the intra-ocular injection of type I virus.

The injection of HSV type I into the vitreous body of the eye in the 18-day-old albino rabbits consistently induces herpes encephalitis with 90% survival. The longterm observations up to 64 days post-inculation indicate that HSV travels slowly by cell-to-cell infection of neuroglia. The lesions follow a defined anatomical pathway producing a progressive disease not dissimilar to the natural human disease. Semiserial (1 micron) sections show that as the infection progresses tissue repair follows. It appears that HSV does not become latent, repeated episodes of viral activity cause further damage with which the repair does not keep pace. By the sixteenth day virus particles and lesions are found in contralateral side of the chiasma, lateral geniculate body and both optic nerves, but not in the ipsilateral geniculate body. This suggests that the virus does not follow the axonal route.

Animals↗