We measured choline (Ch), acetylcholinesterase activity (AChE) and total protein in the cerebrospinal fluid (CSF) of 66 Alzheimer patients (ages 54-89 years) and 22 age-matched controls (ages 52-80 years), looking for markers of the well-established cholinergic deficit and neuronal degeneration in Alzheimer disease (AD). Three or more lumbar punctures were performed in 21 patients over a span of 24 months in order to study the changes in these CSF components with disease progression. We found a statistically significant reduction in AChE and an increase in Ch with advancing dementia. These changes were not related to patient age. We suggest that the rise in CSF choline is related to neuronal membrane breakdown and reduced Ch uptake by cholinergic neurons. The reduction in CSF AChE is consistent with the depletion of cholinergic neurons in AD.

Acetylcholinesterase↗

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Microbiology. Synthesizing designer drugs.

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Anti-Bacterial Agents↗

PubMedDate not supplied

Pulmonary blood volume: correlation of equilibrium radionuclide and dye-dilution estimates.

In fifteen prospective patients with aortic stenosis undergoing transseptal cardiac catheterization, dye-dilution and count-based estimates of pulmonary blood volume (PBV) were performed. Three radionuclide methods were evaluated. Two were based on electrocardiogram (ECG)-gated imaging of the thorax, where pulmonary counts (PC) were corrected for frame-time, venous radioactivity, and either (1) the number of processed heart beats or (2) the total duration of acquisition. The third method involved ungated frame mode acquisitions, where PC were corrected for the duration of acquisition and the venous activity. PC (per channel element) were derived from manual assignments of the right lung. All methods correlated well with standard dye-dilution techniques (r greater than 0.82), though at greater volumes it was clear that count-based methods underestimated the dye-dilution values. In five acutely instrumented, anesthetized dogs, radionuclide (ungated formula) and dye-dilution estimates of PBV were made during multiple interventions (19 data points). The five control count volumes as well as the 14 separate intervention points correlated well (r greater than 0.89). It is concluded that PC from equilibrium blood pool images reflect PBV and that induced changes in PC can be utilized as a reflection of changes in PBV.

Adult↗

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Blood and urine tests for diagnosis and monitoring of diabetes.

The diagnosis of diabetes is made on the evidence of raised blood glucose levels. In diabetic patients, regular monitoring of blood and urine guides decisions about treatment and helps to minimise the risk of complications. This article describes various diagnostic tests that can be used both in the laboratory and outside.

Blood Glucose↗

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Blood transfusion: risks and benefits.

This article describes the basic science involved in the provision of a blood transfusion service. Apart from the life-saving properties of blood transfusion following acute blood loss, much modern surgery could not be contemplated without the availability of safe and compatible blood for transfusion. In addition there are many medical conditions whose therapy depends on blood products.

Blood Donors↗

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Haematology blood testing for anaemia.

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Anemia↗

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Diagnosis of acute and chronic cardiac rejection by magnetic resonance imaging: a non-invasive in-vivo study.

To evaluate the potential usefulness for characterization of tissue and anatomical changes associated with cardiac transplantation rejection by nuclear magnetic resonance imaging (MRI), sixteen dogs underwent heterotropic cardiac transplantation with six not immunosuppressed serving as controls. Myocardial biopsy and MRI were obtained and compared on a weekly basis. Untreated allografts showed a significant increase in T2 and intensity values by MRI compared to the native heart as early as one week after transplantation. The MRI findings corresponded to the histological progression of acute rejection process in both treated and untreated groups. The linear relationship between histology and MRI was 0.72 while the correlation between T2 and the water content was 0.92. Serial gated MRI correlated with chronic anatomical changes of transplant rejection with evidence of progressive or increasing myocardial wall thickness and decrease in ventricular chamber size.

Animals↗

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Deficiency testing for iron, vitamin B12 and folate.

Dietary cells and the vitamins B12 and folate are necessary for the production of the red blood cells (erythrocytes), which carry oxygen from the lungs to the tissues and carbon dioxide from tissues to lungs. Deficiency of either one results in anaemia, which is characterised by low haemoglobin concentration. Symptoms result from reduced tissue oxygenation and include weakness, lethargy, palpitation, headache and shortness of breath. The first-time laboratory test of all patients suspected of being anaemic is the full blood count. Results of a full blood count may suggest the anaemia is caused by a nutritional deficiency of B12 folate or iron. Laboratory measurement of the concentration in blood of iron and vitamin B12 and folate, along with several other tests described here, are useful in the differential diagnosis of the anaemic patients.

Adult↗

PubMedDate not supplied

Microbiological examination of urine in urinary tract infection.

Normally, urine in the bladder and the urinary tract from kidney to the last third of the urethra is sterile. When the urinary tract becomes infected with bacteria, an inflammation at the site of infection results in symptoms of urinary tract infection (UTI), and significant numbers of bacteria and white blood cells (WBC) appear in the urine. This paper describes how, by the examination of urine, the clinical microbiology laboratory contributes to the diagnosis, monitoring and treatment of UTI.

Humans↗

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Microbiological examination of blood for septicaemia.

The immune defences of blood are normally sufficient to protect against infection by the few bacteria that occasionally find their way into the peripheral circulation. When these host defence mechanisms are overwhelmed, uncontrolled bacterial infection of the blood (septicaemia) develops. Septicaemia is a potentially life-threatening clinical emergency that demands urgent diagnosis and treatment. This paper describes some aspects of septicaemia and the way in which the microbiology laboratory contributes to the care of patients suspected of having septicaemia.

Cross Infection↗

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An introduction to the examination of specimens.

This paper is the first of a series describing how laboratory examination of specimens contributes to the diagnosis and monitoring of disease. It offers a brief introduction to each of the disciplines within pathology, along with a general consideration of normal range, units of measurement and specimen collection.

Allergy and Immunology↗

PubMedDate not supplied

Measuring renal function with urea and creatinine tests.

The second paper in our series on laboratory examination of specimens discusses the measurement of urea and creatinine in the blood as tests of renal function. It outlines the synthesis of urea and creatinine and their excretion following glomerular filtration.

Biomarkers↗

PubMedDate not supplied

Pathology testing of blood glucose levels.

Reduced and raised blood glucose concentration (hypoglycaemia and hyperglycaemia respectively) are symptoms of a number of conditions besides diabetes mellitus. The third paper in our series describes these conditions and methods used to assess blood glucose levels.

Blood Glucose↗