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M Sha

Publications and source records attributed to M Sha.

49 records · Page 3Linked to original sources
PubMed1993

[Power spectrum of experimental gas embolism in dogs and a new device for its detection].

We studied the power spectrum of precordial Doppler sounds during experimental CO2 and air embolism and developed a new device for detection (intravascular gas detector) and examined its usefulness in experimental CO2 and air embolism in dogs and in a patient during laparoscopic surgery. We did digital tape recordings during CO2 and air embolism in seven anesthetized mongrel dogs (7-16 kg body) to generate power spectrum of the heart sound on a dynamic signal analyzer. The power spectrum of "mill-wheel murmur" was found to be 10-30 dB higher than the baseline heart sound in the range of 200 and 2500 Hz. The intravascular gas detector was designed to set off alarm sounds whenever the difference of energy between the Doppler sounds low-pass filtered at 250 Hz and the Doppler sounds high-pass filtered at 250 Hz was increased. The alarm was activated immediately during experimental CO2 and air embolism and also during laparoscopic appendectomy. The alarm sounds during the appendectomy coincided with gas bubbles detected by a transesophageal echocardiography. By use of this detector, CO2 and air embolism can be easily detected and the anesthesiologist does not need to pay continuous attention to Doppler sounds by diverting his or her concentration on the patient.

Animals↗
PubMed1987

Detection of guinea pig cytomegalovirus nucleic acids in cultured cells with biotin-labelled hybridization probes.

Biotin labelled hybridization probes prepared from recombinant plasmids containing segments of the guinea pig cytomegalovirus (GPCMV) genome were used to detect GPCMV nucleic acids in guinea pig cells by in situ hybridization. The time course of GPCMV infection was assessed in two cultured cell types, guinea pig embryo (GPE) cells and 104C1 cells, a transformed and cloned guinea pig cell line. Detection of GPCMV nucleic acids was accomplished in both cell types with individual GPCMV DNA fragments and with mixtures of GPCMV DNA fragments. When compared to other established methods of GPCMV detection, the method of in situ hybridization enabled the detection of a higher percentage of positive cells early during the course of the infection. In addition, differences in the replication cycle of GPCMV in the two cultured cell lines could be demonstrated. These findings will facilitate future studies of GPCMV tissue tropism in vivo.

Animals↗
PubMed1987

Effects of continuous positive-pressure ventilation on hepatic blood flow and intrahepatic oxygen delivery in dogs.

The effect of mechanical ventilation with PEEP of 0, 10, and 20 cm H2O (continuous positive-pressure ventilation [CPPV]) on hepatic blood flow (HBF) and intrahepatic oxygen delivery was studied in 26 mongrel dogs anesthetized with fentanyl. Hepatic arterial and portal venous blood flow was measured by an electromagnetic flowmeter. CPPV caused a significant decrease in HBF, which was related to the PEEP level. A linear correlation was seen between HBF and cardiac output. Intrahepatic oxygen delivery decreased more than HBF and cardiac output. The reduced oxygen delivery was due mainly to the decrease in portal venous oxygen content.

Animals↗
PubMed1981

Ventilatory response to CO2 in patients after long-term ventilation for acute respiratory failure secondary to chronic obstructive lung disease.

Ventilatory response to CO2 was examined in 6 patients with severe chronic obstructive lung disease (COLD) shortly after discontinuance of long-term ventilation for acute respiratory failure (ARF). Ventilatory response to CO2 was extremely low in all patients 6-10 h after discontinuance from ventilator. Our month later, however, CO2 response curves shifted to the left and in 3 patients there was improvement which was seen in the slope of response curve. In patients who had mechanical ventilation for ARF from COLD, abnormally low responses to CO2 probably contribute to the difficulty in weaning from mechanical ventilation. The presence of reduced CO2 responsiveness should be considered in these circumstances.

Aged↗
PubMedDate not supplied

An in vivo 19F NMR study of isoflurane elimination as a function of age in rat brain.

In vivo 19F NMR at 4.7 T has shown that the biphasic elimination of the vapor anesthetic isoflurane from rat brain is ca 15% slower in old (23-24 months) animals compared with young (5-6 months) animals. The fast kinetic component has a t1/2 of ca 7-9 min and the slow event, 100-115 min. Gas chromatographic measurement of arterial blood elimination displays age attenuation to the same extent, although a monophasic kinetic process (6-7 min). The slow wash-out from brain is thought to involve elimination from intracranial fatty tissue as postulated by others in rabbit brain. Longitudinal relaxation time measurements show monoexponential recovery and essentially identical values for young (1.09 + 0.11 s) and old (1.04 +/- 0.09 s) animals. For dipalmitoylphosphatidylcholine vesicles the monoexponential recovery also suggests rapidly exchanging averaged homogeneous lipid environments for the anesthetic, but the longer T1s (2.75 +/- 0.25 s) imply less restricted mobility compared with brain. Single T2 values were obtained in vivo, indicating either a single compartment or rapid exchange between multiple environments. These measurements were inconsistent, undoubtedly as a result of B1 inhomogeneity. The age-attenuated elimination kinetics for isoflurane are consistent with poorer cardiopulmonary function, whereas the T1 data suggest similar environments for the anesthetic in young and old brain tissue.

1,2-Dipalmitoylphosphatidylcholine↗