Dementias appear to have individual profiles in single photon emission computed tomography

Article Abstract:

A group of researchers applied single photon emission computer tomography (SPECT) imaging to investigate the physiologic and metabolic activity and blood flow in the brains of patients suffering from impaired intellectual function, or dementia. Their goal was to more accurately identify the areas of the brain involved in the pathologies of various dementias and, more importantly, to detect abnormal concentrations of neurotransmitters. Neurotransmitters are chemicals which provide communication between brain cells and are intimately related to brain functioning. Initial investigations were done using positron emission tomography (PET) technology, a very expensive imaging method that requires a cyclotron to create the radioactive chemicals needed for the procedure. The development of several new radioactive tracers allowed this research to be completed with the considerably cheaper SPECT system (using commercially prepared radioactive tracers). Once the radioactive tracers or labels are injected into the patient, peak brain concentration is reached in approximately 20 minutes and it remains sufficiently high for approximately one hour. This period is sufficient for the imaging procedure. In normal individuals, the uptake of the radioactive material occurs in a uniform level throughout all anatomic layers of the cerebral cortex, cerebellum and deeply-located cell aggregates within the brain (basal ganglia). The pattern of uptake in patients with dementia is distinctive and shows areas of reduced collection of the radioactive agent. At this time, the greatest number of patients studied are suffers of Alzheimer's disease, or premature senile dementia. On SPECT, these patients often exhibit changes in the parietal lobes of the cerebral cortex. Other dementias show similar types of distinctive pathologies. Rapid progress in imaging procedures is expected to bring with it new understandings and, perhaps, better therapies for patients with dementia.

Evaluation, Dementia, Magnetic resonance imaging, PET imaging, Positron emission tomography

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It's too early to tell, but polypeptide growth factor research already generates some enthusiasm

Article Abstract:

Participants at a biotechnology industry conference agreed that research into the use of polypeptide (chains of amino acids) growth factors is still in its very early stages. There are about 60 U.S. companies, and more than 100 companies world-wide, pursuing research in this area. Polypeptide growth factors, which help promote wound-healing, may be on the market in three to five years. It is predicted that by the year 2000 the market for growth factors will be worth $5 billion annually. To date 15 to 30 growth factors have been identified. The exact number is uncertain because most of these polypeptides have not been fully described, and some groups of researchers may be looking at the same substance, but calling it by different names. One platelet- derived wound-healing formula has achieved satisfactory results in human trials while nicotinamide and reverse triiodothyronine are very promising growth factors being evaluated for use as wound-healing agents. The success of these substances has spawned a commercial venture, Cura-Tech, Inc. (Setauket, NY) which has established eight for-profit wound-healing clinics in the U.S. Treatment costs currently range from $1,000 to $3,500.

Health aspects, Growth factors, Platelet-derived growth factor

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Microbubbles show promise for enhancing ultrasound signal, image, other applications

Article Abstract:

Researchers have begun to use very small air bubbles (microbubbles) as to improve contrast in images of the heart produced by ultrasound (US). Air is encased in microscopic bubbles that can be injected into the bloodstream: when US waves hit the bubbles, they bounce right back, providing a strong signal and a better image. Commercially-prepared bubbles composed of human albumin (a simple protein group) are being made by Molecular Biosystems, Inc. (San Diego, CA.). Albumin bubbles have a shelf-life of up to nine months. These microbubbles can be used to visualize chambers of the heart, compute ejection fractions (percentage of blood expelled from the ventricles of the heart), and help delineate blood perfusion in heart muscle. Another commercially-available contrast agent, Renografin, contains a small amount of contrast agent to enhance US images even more. Investigators are testing Renografin during bypass surgery. Researchers speculate that microbubble US imaging may prove useful for imaging cerebral arteries, and could possibly be an important means of imaging site-specific drug delivery.

Methods, Usage, Diagnostic imaging, Bubbles, Contrast echocardiography

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