Search PubMed⌕ Search

Biomedical subjects

S J Read

Publications and source records attributed to S J Read.

53 records · Page 3Linked to original sources
PubMed1995

Neurological disease associated with Mycoplasma pneumoniae infection. PCR evidence against a direct invasive mechanism.

Aims-To investigate the pathology in patients presenting with sudden onset neurological illnesses associated with Mycoplasma pneumoniae infection.Methods-M pneumoniae infection was diagnosed by a highly rigorous interpretation of serological markers initially using complement fixation, agglutination and IgM antibodies. Confirmation of the serological diagnosis was achieved using indirect immunofluorescence for IgM, IgA, and IgG. Serum and cerebrospinal fluid (CSF) samples from these patients were examined using the polymerase chain reaction to look for evidence of M pneumoniae DNA.Results-No M pneumoniae DNA was found in any serum or CSF samples. Diagnosis of M pneumoniae infection by agglutination and complement fixation antibodies was not always confirmed by indirect immunofluorescence.Conclusion-The neurological lesions in these patients do not appear to be caused by the direct invasion of M pneumoniae into the nervous system. The lesions may be an immune response to infection. Serological diagnosis of M pneumoniae continues to be a laboratory problem.

Journal Article↗
PubMed1995

Direct sample polymerase chain reaction for the detection of Mycoplasma pneumoniae: a simple system for clinical application.

A semi-nested polymerase chain reaction system with primers derived from the P1 adhesin gene of Mycoplasma pneumoniae was evaluated for sensitivity and specificity for detection of M. pneumoniae. The method used target DNA within samples of M. pneumoniae broth cultures and clinical material, without a formal extraction process. The sensitivity for detection of DNA was found to be to a level of one copy per sample and was specific to M. pneumoniae only, discriminating from the other human mycoplasma and ureaplasma species tested. The system offers the opportunity for a simple and highly specific laboratory method for diagnosis which may be compared to currently available serological methods, and may provide another method of studying mycoplasma-induced pathology.

Base Sequence↗
PubMed1993

Low risk of sexual transmission of hepatitis C virus.

Sexual transmission of hepatitis C virus (HCV) was studied between 104 anti-HCV positive index cases (99 haemophilic men, five women) who have attended the Oxford Haemophilia Centre and 104 (98 female, 6 male) longstanding sexual partners. Ninety-one percent of the index cases were HCV RNA positive by the polymerase chain reaction (PCR) and 56% were anti-human immunodeficiency virus (HIV) positive. Three (2.9%) sexual partners (each a female partner of a different HCV RNA positive haemophilic man) were anti-HCV, and HCV RNA, positive. All had other risk factors for HCV infection. Of 59 partners who were tested for anti-HIV four (7%) were positive and only one of these was also anti-HCV positive. There was no association between HIV positivity in the index cases and HCV positivity in their partners. Our results confirm a low risk of sexual transmission of HCV.

Adult↗
PubMed1993

Acute herpes hepatitis in pregnancy.

A 36 year old primigravid woman presented with a "flu-like" illness and premature labour, followed by severe pneumonitis and hepatitis in the late second trimester of pregnancy. Progressive deterioration obliged an elective delivery of twins, stillborn at 25 weeks of gestation. Herpes virus isolated from one placenta, but not from any fetal tissue, was the only indication of a systemic herpes simplex infection in which there were no mucocutaneous lesions seen before or during the illness. There was no history of herpes simplex infection and antibody studies were not helpful initially for a diagnosis that was confirmed in retrospect. Double staining for viral DNA and antigen showed that the virus was present in host monocytes.

Adult↗
PubMed1992

Demand incidence and episode rates of ophthalmic disease in a defined urban population.

OBJECTIVES: To estimate demand incidence and episode rates of ophthalmic disease in a defined urban population over one year. DESIGN: Study of patients presenting with eye problems to general practice and eye casualty department. SETTING: General practice and ophthalmic services in west Nottingham. SUBJECTS: 36,018 people from the combined practice lists of 17 Nottingham general practitioners. MAIN OUTCOME MEASURES: Ophthalmic disorder, age and sex of patient, and where presented. RESULTS: 587 consultations were recorded for ophthalmic problems, 1771 with general practitioners and 816 with eye casualty. Most consultations to general practice were by females (1066 (60%)), whereas men aged 15-44 accounted for most work in eye casualty. These men commonly presented with trauma. Infective conjunctivitis, the commonest condition, had an episode rate of 13.5/1000 population/year. Demand incidence for cataracts was 1.9/1000 population/year. Demand incidence for chronic conditions increased with age. CONCLUSIONS: As the average age of the population increases demand for ophthalmic services will rise. Planning and provision of resources to meet this increased demand should be considered now.

Age Factors↗
PubMed1992

Failure to detect cytomegalovirus DNA in pancreas in type 2 diabetes.

We have attempted to confirm the finding of cytomegalovirus (CMV) nucleic acid sequences in pancreas sections from patients with type 2 diabetes in a large population since this finding has major implications for the pathogenesis of the disorder. A highly sensitive nested polymerase chain reaction method was developed to detect the immediate-early CMV gene in DNA extracted from wax-embedded tissue sections. We could not confirm the previous findings; CMV DNA was not detected in pancreas sections from 43 type 2 diabetic patients or from 38 non-diabetic age-matched subjects, although the method detected CMV DNA, even in very low concentrations, in positive controls.

Adult↗
PubMed1992

Chicken pox infection (varicella zoster virus) and acute monoarthritis: evidence against a direct viral mechanism.

A 9 year old boy developed acute monoarthritis of the left knee concurrent with the appearance of a varicella zoster virus (VZV) rash. Repeated VZV DNA hybridisation of the cells within the synovial fluid and synovial membrane failed to show any evidence of intracellular virus. Virus was isolated from synovial fluid 24 hours after the start of clinical infection but not later. These findings suggest that the mechanism of the arthritis is not due to viral replication inside the swollen joint.

Acute Disease↗
PubMed1990

Performance characteristics of a novel immunoassay based on hybrid Ty virus-like particles (Ty-VLPs): rapid differentiation between HIV-1 and HIV-2 infection.

Recombinant antigens containing all or parts of the HIV-1 proteins p24, Nef and gp41 and HIV-2 gp36 have been purified and used to develop a rapid immunoassay to detect and differentiate between HIV-1 and HIV-2 antibodies in a single test. The antigens were produced as particulate fusion proteins by exploiting the ability of a protein encoded by the yeast retrotransposon Ty to assemble into virus-like particles (Ty-VLPs). Hybrid HIV: Ty-VLPs carrying each of the antigens were applied to nitrocellulose strips at specified locations in a slot-blot format and then used to detect antibodies present in human serum and plasma samples of diverse geographical origin. Previously confirmed HIV-1- and HIV-2-positive samples were readily and reliably identified. The assay was used to identify a case of HIV-2 infection in an African woman who had been resident in the Oxford region for the last 3 years and to analyse the prevalence of anti-HIV antibodies in a longitudinal study of seroconverting patients. We also demonstrate that the assay works efficiently with whole blood.

Adult↗
PubMed1989

The role of causal sequence in the meaning of actions.

Single actions, taken out of context, typically have numerous meanings. Yet, when we observe such actions as part of a sequence of behaviour, we are often unaware of this multiplicity of possible meanings. In this article, we argue that the specific meaning of an action is the result of a process in which people, by making appropriate inferences, relate the actions in a sequence to each other and construct a coherent scenario from them. One implication of this position is that the meaning of actions should be extremely sensitive to the order in which they occur, since order affects which knowledge structures are currently active and is an important clue to the causal and means-end relations among actions. In fact, meaning should be so sensitive to order that it should be possible to construct sets of actions, such that merely by changing the order, the same set of actions could have two radically different meanings. Five sets of such actions were designed. Subjects read one of the two orders for each set of actions and then answered a number of open-ended questions about them. Subjects receiving different orders identified different causes and reasons for the actions, made different predictions about what would happen next, and came to different conclusions about the identities of actors and and objects in the sequences, thus indicating that they had constructed very different meanings for the same actions.

Concept Formation↗
PubMed1987

Constructing causal scenarios: a knowledge structure approach to causal reasoning.

A model of causal reasoning based on Schank and Abelson's (1977) analysis of knowledge structures is presented. The first part of this article outlines the necessary characteristics of such a model. It is argued that a central attributional problem is to explain extended sequences of behavior. To do this people must relate actions in a sequence to one another and construct a coherent scenario from them. Because the relation among actions is not given, people must use detailed social and physical knowledge to make connecting inferences. The resulting scenario typically includes information about the plans and goals of the actor. The second part of this article analyzes how the knowledge structures outlined by Schank and Abelson (1977)--scripts, plans, goals, and themes--can be used to construct such causal scenarios, and it presents a process model for the construction of such scenarios. The last part of this article examines the implications of this model and its relations to other attribution models by Kelley (1967, 1971a, 1971b) and Jones (Jones & Davis, 1965; Jones & McGillis, 1976).

Cognition↗
PubMedDate not supplied

Experience with diffusion-weighted imaging in an acute stroke unit.

We performed diffusion-weighted MRI (DWI) on a standard 1.5-tesla MRI scanner using a high-speed stimulated echo pulse sequence (turboSTEAM) in 9 stroke patients and 9 control subjects to investigate whether this technique can be used clinically to assist in ischaemic stroke diagnosis within the time frame for potential therapy. Stroke patients underwent DWI between 3.75 h and 3 days after stroke onset. Three patients were studied on more than one occasion. DWI was normal in the 9 controls. Seven of 9 stroke patients showed areas of increased signal on DWI. DWI detected cerebral ischaemia 3.75 h after stroke onset when both CT and T2-weighted MRI were normal. In 6 DWI-positive patients studied at later times, increased signal on T2-weighted images was present at the same time. Two patients had normal CT, T2-weighted and DWI images; both made good neurological recoveries. For the routine assessment of stroke patients, DWI implemented on a standard MRI system can provide additional information of clinical value to that obtained with conventional pulse sequences. In particular it facilitates early detection of cerebral ischaemia during the first few hours after stroke.

Adult↗
PubMedDate not supplied

White matter medullary infarcts: acute subcortical infarction in the centrum ovale.

Acute infarction confined to the territory of the white matter medullary arteries is a poorly characterised acute stroke subtype. 22 patients with infarction confined to this vascular territory on CT and/or MRI were identified from a series of 1,800 consecutive admissions to our stroke unit (1.2%) between August 1993 and March 1997. 19 patients had small infarcts (< 1.5 cm maximum diameter) and 3 large infarcts (> 1.5 cm). Small infarcts were associated with a history of smoking (69%), hypertension (58%), and hyperlipidaemia (37%), and less frequently with atrial fibrillation (21%). Significant (>50%) ipsilateral carotid stenosis (16%) was a less frequent finding in this group. Patients most commonly presented with weakness and/or sensory disturbance affecting mainly the upper limbs, but dysarthria, dysphasia, and ataxia were also seen. Large infarcts were infrequent in our series, but did not differ significantly from small infarcts with respect to clinical presentation or risk factor profiles (p > 0.05 for all comparisons). The majority of symptomatic patients with white matter medullary infarcts are associated with small (< 1.5 cm diameter) lesions and a risk factor profile consistent with small vessel disease. More data are required to elucidate the mechanism of larger (> 1.5 cm) infarcts. Because of the potential overlap between white matter medullary infarcts and internal watershed infarcts, suggested criteria for each are presented.

Acute Disease↗