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Biomedical subjects

M Sun

Publications and source records attributed to M Sun.

At least 289 records · Page 16Linked to original sources
PubMed1988

Radon's health risks.

Explore the source record for details and available documents.

Air Pollutants, Radioactive↗
PubMed1988

Recording and processing aneurysmal vibration signals in dogs.

A specially designed computerized acoustic aneurysm detection system has been developed and used for recording the acoustic signal produced by aneurysms in dogs. Two transducer types, a modified horn-coupled microphone and a microvascular intra-operative Doppler flowmeter have been used. The results show that the aneurysm signal is time-varying and that a stronger vibration signal can be obtained if a proximal stenosis presents. With direct contact recording, the acoustic signals from aneurysms and parent arteries show different characteristics that can be easily distinguished. The aneurysm signals are processed by spectrograms, and a smoothing technique for suppressing noise is introduced.

Acoustics↗
PubMed1988

Characteristics of the immune response to poliovirus virion polypeptides after immunization with live or inactivated polio vaccines.

Groups of infants were immunized with high-potency, inactivated polio vaccine (IPV) or live, attenuated oral polio vaccine (OPV) and studied for antibody responses to whole virus and polypeptides VP1, VP2, and VP3. Both vaccines induced neutralizing and enzyme-linked immunosorbent assay (ELISA) IgG to the whole virus, IgG antibody to VP1 and VP3, and similar secretory IgA to VP1 and VP2 in the nasopharyngeal secretions (NPS) without any VP3 response. Virus-specific neutralizing activity in NPS was observed in 70% of subjects receiving OPV and in only 26.7% of subjects receiving IPV. ELISA antibody also appeared to be lower in IPV than in OPV subjects. These observations suggest that specific ELISA antibody to poliovirus virion proteins can be frequently induced in the secretory sites, by OPV as well as by IPV. Neutralizing antibody response in the NPS appeared, however, to be more effectively induced by OPV than by the high-potency IPV.

Antibodies, Viral↗
PubMed1988

Intra-aneurysmal pressure measurements in experimental saccular aneurysms in dogs.

Intra-aneurysmal pressure was studied in an experimental model of saccular aneurysm in dogs, using a vein pouch grafted onto a common carotid arterial bifurcation. The mean and the pulse pressures were recorded simultaneously from within the aneurysm and within the common carotid artery, before and after 50% proximal carotid artery stenosis. These experiments were performed under systemic normotension, hypotension, and hypertension. Normal data suggest that mean intracarotid and intra-aneurysmal pressures are similar and relate in a nearly linear fashion to mean arterial pressure. However, after 50% stenosis, the data had a cubic relationship, the reduction of pressure occurring only in the middle range of mean arterial pressure. Both intra-aneurysmal and intracarotid pulse pressures displayed less dependence on mean arterial pressure. However, sigmoid curves also were observed with the pulse pressures after 50% proximal common carotid artery stenosis. In all cases, after 50% stenosis, the rate of increase of the pulse pressures with mean arterial pressure was greater for higher mean arterial pressures. Our preliminary data indicate that a detailed study of intra-aneurysmal pressure and blood flow in relation to systemic variables such as mean arterial pressure, cardiac output, and peripheral resistance may not only suggest improved means of managing patients with intracranial aneurysms, but also may raise the possibility that, under certain conditions, higher intra-aneurysmal pressures may be induced by downstream stenosis.

Animals↗
PubMed1987

An acoustic aneurysm-detector.

Intracranial aneurysms have a high prevalence in the adult population; and if they rupture, significant morbidity almost always ensues. However, pulsatile blood flow through aneurysms produces vibrational sound patterns that may be detected extracranially. Thus, an acoustic aneurysm-detector has been developed to detect the sounds produced by intracranial aneurysms prior to rupture. The design is based on the utilization of a hydrophone for signal detection and computational signal processing for signal extraction. Data are examined in the time domain, the frequency domain, and the time-frequency plane. Examples are presented from an animal model and from a patient with a known aneurysm.

Adult↗