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Biomedical subjects

T Forsey

Publications and source records attributed to T Forsey.

At least 37 records · Page 2Linked to original sources

Comparison of the nucleotide sequence of the SH gene and flanking regions of mumps vaccine virus (Urabe strain) grown on different substrates and isolated from vaccinees.

The small hydrophobic (SH) protein gene and flanking regions of the Urabe Am9 vaccine strain of mumps virus were amplified by the polymerase chain reaction and sequenced directly by the dideoxynucleotide chain termination method. The 434 bp sequence was identical for the Urabe strain isolated from vaccines produced by three manufacturers and for virus isolated following post-vaccination parotitis. No changes were detected for coding, non-coding or intergenic regions between virus grown on different substrates. The Urabe virus SH coding region differed from the published sequence for strain SBL-1 by 14.4% at the nucleotide level and 24.6% at the amino acid level. The 5' non-coding SH region was strongly conserved between the two strains (2% different), whereas the other non-coding regions were not.

Amino Acid Sequence↗

Differentiation of vaccine and wild mumps viruses using the polymerase chain reaction and dideoxynucleotide sequencing.

Parts of the F gene from 16 mumps viruses derived from vaccines and clinical isolates were amplified using the polymerase chain reaction and their nucleotide sequences were determined. Over a region of 111 nucleotides, eight regions of variability were detected with a maximum of six (5.4%) changes occurring between any two virus strains. The Jeryl Lynn and Urabe vaccine strains were clearly different from each other and from wild virus isolated from cases of non-vaccine-associated mumps. In contrast, viruses isolated from the cerebrospinal fluid and throat in cases of meningitis and parotitis following vaccination with the Urabe strain were identical to this strain. We conclude that the vaccine was the source of these infections.

Base Sequence↗

Diagnosis of ophthalmia neonatorum.

Ninety consecutively seen babies with eye discharge in the first three weeks of life were examined. Four babies had "sticky eyes" with no evidence of ophthalmia and had uniformly negative cultures and test results for antichlamydial antibody; these babies were excluded. Of the 86 babies with ophthalmia neonatorum, Neisseria gonorrhoeae was isolated from eight, Chlamydia trachomatis from 44, other bacteria alone from 20, and 14 had negative cultures. Three babies with negative cultures had longstanding conjunctivitis and had been treated with chloramphenicol eye ointment; all had antichlamydial IgM antibodies, indicating that the conjunctivitis was chlamydial. Hence the total number of babies whose conjunctivitis was chlamydial was 47. The result of the Gram stained conjunctival smear correlated well with that of culture and final assessment by the microimmunofluorescence test, enabling an immediate presumptive diagnosis to be made of gonococcal, chlamydial, or bacterial conjunctivitis. Prompt and effective treatment of babies was started. Explanation to the mother and contact tracing were carried out when the confirmatory cultures and antibody tests were completed. The Gram stained conjunctival smear is a highly sensitive, specific, and predictive test for the aetiological agent of ophthalmia neonatorum. By virtue of its simplicity and rapidity the test may be useful in developing countries.

Antibodies, Bacterial↗

Chlamydial and gonococcal ophthalmia neonatorum in The Gambia.

Swabs were taken for isolation of Chlamydia trachomatis and Neisseria gonorrhoeae from 112 infants with ophthalmia neonatorum attending a hospital in The Gambia. C. trachomatis was isolated from 37 (33%) and N. gonorrhoeae from 28 (25%), with both organisms being present in three cases (3%). A prospective study of 335 neonates was also undertaken in a Gambian town. Fifty-five infants (16%) showed clinical evidence of ophthalmia neonatorum. C. trachomatis was isolated from nine of these (16%) and N. gonorrhoeae from seven (13%).

Chlamydia trachomatis↗

Comparison of two immunofluorescence tests for detecting antibodies to C. trachomatis.

Two immunofluorescence tests were compared for detecting antibodies to chlamydiae. The inclusion antigen test was more sensitive, detecting antibodies in more sera and at higher titres. The micro-IF test was more specific, differentiating between antibodies to C. trachomatis and those to C.IOL 207. Antibodies to this non-genital chlamydial type accounted for half the positive results. These antibodies can cause the prevalence of C. trachomatis infections to be over estimated when genus-specific serology tests are used.

Antibodies, Bacterial↗

Prevalence in human beings of antibodies to Chlamydia IOL-207, an atypical strain of chlamydia.

Samples of serum from 18353 persons from the U.K. and abroad, were tested for type-specific antibodies to Chlamydia spp. Antibodies to an atypical strain, Chlamydia IOL-207, were detected in each population tested. Overall, the prevalence of these antibodies (19.9%) was similar to that of antibodies to C. trachomatis (21.6%). In the U.K., antibodies to C. IOL-207 were rare in children under the age of 5 years but became more common with increasing age. In adults the prevalence of these antibodies increased annually between 1979 and 1984. Antibodies to C. IOL-207 were not associated with sexually transmitted disease and only rarely with ocular disease. Their association with a common complaint such as mild respiratory illness is postulated. The presence of these antibodies within a population may lead to the over-diagnosis of C. trachomatis infections or psittacosis if only genus-specific serological tests are used.

Adolescent↗

Antibodies to herpes simplex virus type I in intraocular fluids of patients with acute retinal necrosis.

The intraocular fluids and sera from three patients with acute retinal necrosis (ARN) and from 120 age-matched controls were tested for the presence of antibodies to herpes simplex virus type I (HSV-I). Antibodies to HSV-I were detected in both intraocular fluids and sera of two cases, and in intraocular fluids alone in one case of ARN. Among 120 control patients undergoing routine intraocular surgery antibodies to HSV-I were detected in the sera of 85 (79.2%) but in the intraocular fluids of only two (1.7%). The presence of antibody within the eye may indicate local antibody production, antibody sequestration within the eye, or damage to the blood ocular barrier.

Adolescent↗

Sequential antibody changes following ulcerative herpetic keratitis.

Blood and tear levels of immunoglobulins against herpes simplex virus (HSV) were examined in 28 patients with dendritic keratitis over a period of 28 days. By means of an indirect micro-immunofluorescent technique blood and tear HSV IgG were detected, but neither circulating HSV IgM nor local HSV IgA were found. Over a four-week interval non-diagnostic fluctuations of HSV IgG occurred in most patients, though seven (25%) developed a rising blood IgG titre. Tear IgG appeared to be an exudate from blood. HSV was isolated from 68% of corneal swabbings and 11% of conjunctival swabbings. This study provides guidelines for laboratory testing in recurrent herpetic keratitis.

Adolescent↗

Failure of in vitro fertilization and embryo replacement following infection with Chlamydia trachomatis.

Antibodies to Chlamydia trachomatis were detected in 54 (47.4%) of 114 infertile women attending Bourn Hall Clinic. Antibodies were solely of the IgG class and mainly of a low titer, suggesting past infection. Antibodies were found in significantly more patients with tubal damage (54.4%) than in women whose infertility was due to other causes (16.6%). Seventy-two women completed in vitro fertilization, with 52 having three embryos replaced. We found that this treatment offered the optimum chance of a pregnancy being established, and 20 (38.5%) of these women became pregnant. Antibodies to C. trachomatis were present in only six (30.0%) of the women becoming pregnant, whereas antibodies were found in 21 (65.6%) of those who failed to become pregnant. Thus past infection with C. trachomatis halved the success rate of in vitro fertilization in these patients. The implications of these findings are relevant to all aspects of infertility from prevention to in vitro fertilization treatment.

Adult↗

Seroepidemiological survey of chlamydial genital infections in Khartoum, Sudan.

A total of 494 patients (90 men and 404 women) attending a sexually transmitted diseases (STDs) clinic in Khartoum, Sudan, were studied to assess the prevalence of chlamydial genital infections. Antibodies to Chlamydia trachomatis serotypes D to K were found in four (4.4%) men and 42 (10.4%) women, and 10 (2.5%) women had antibodies to serotypes A to C.

Adolescent↗

Evidence of chlamydial infection in infertile women with and without fallopian tube obstruction.

This study investigates the prevalence of Chlamydia trachomatis antibodies in 164 infertile women who underwent diagnostic laparoscopy and dye insufflation as part of routine infertility investigations. C. trachomatis antibodies were found in 36 (22%) of 164 infertile women, which was significantly more than the prevalence of antibodies in a control group (22 of 200, 11%). C. trachomatis antibodies were found in 25 (35.7%) of 70 infertile women who had laparoscopically verified peripheral tubal disease. This was significantly more than the prevalence of C. trachomatis antibodies in infertile women with normal fallopian tubes (6 of 52, 11.5%). The prevalence of C. trachomatis antibodies in infertile patients with laparoscopically verified cornual disease was similar to those without cornual disease. C. trachomatis was not isolated from any of the patients studied. This study confirms that past chlamydial salpingitis is associated with the development of peripheral fallopian tube obstruction with resultant infertility.

Adult↗

The epidemiology of chlamydial infections in childhood: a serological investigation.

Blood samples from 382 children between the ages of one and 15 years were tested for anti-chlamydial antibody. A low prevalence of antibody against Chlamydia trachomatis was found among children under the age of seven years. Antibody against the Chlamydial agent C IOL-207 was rare before the age of five years, but was found with increasing prevalence in older children. It is suggested that the mode of transmission of the two agents is different and that C IOL-207 may be transmitted at school.

Adolescent↗