Biomedical subjects

S Z Lin

Publications and source records attributed to S Z Lin.

At least 73 records · Page 4Linked to original sources

PubMed1991

The effects of chronic serum sickness on albumin distribution and glucose utilization in rat brain.

The level of cerebrospinal fluid (CSF) protein is elevated in diseases and disease models that are associated with circulating immune complexes such as serum sickness. Circulatory immune complexes are known to deposit in the basal lamina of fenestrated capillaries and may, as a result, affect both capillary bed and parenchymal function. Since the brain has both fenestrated and unfenestrated capillaries and immune complexes deposit to a varying extent in the fenestrated capillaries in chronic serum sickness, cerebral capillary permeability to protein may be altered in some brain areas and lead to the elevation of CSF proteins. In addition various other cerebrovascular and metabolic functions may also be affected by this condition. In this study either radio-iodinated serum albumin (RISA) or 2-[14C]deoxyglucose (14C-2DG) was intravenously injected into control Wistar rats and Wistar rats with chronic serum sickness; subsequently the tissue levels of radioactivity were measured by quantitative autoradiography in 4 brain areas with fenestrated capillaries and 11 brain areas with unfenestrated capillaries. The 2-min distribution of RISA, which demarcates the volume of circulating plasma in perfused microvessels and is generally proportional to local plasma flow, was the same in control and experimental rats. The passage of RISA from blood into brain over 30 min was negligible in both groups; thus cerebral capillary permeability to albumin was not detectably increased in any of these 15 brain areas by chronic serum sickness. The rate of local cerebral glucose utilization, an indicator of local metabolic and neural activity, was calculated from the 14C-2DG data and was virtually identical in control and experimental rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗

PubMed1991

Effects of amobarbital on pterins and dinucleotides contents in rat brain.

The effects of amobarbital (50 mg.kg-1 ip) on the brain concentrations of biopterin, pterin, reduced nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) were studied by a reverse phase high performance liquid chromatography with fluorescent detector. Amobarbital increased FAD concentrations in 5 brain areas and pterin concentration in the cortex, but decreased biopterin concentrations in the cortex and hippocampus.

Amobarbital↗

PubMed1990

High-field nuclear magnetic resonance techniques for the investigation of a beta-cyclodextrin:indomethacin inclusion complex.

The inclusion complex of indomethacin sodium salt in beta-cyclodextrin has been studied by proton NMR at high magnetic field. The continuous variation technique was used to evidence the formation of a soluble 1:1 complex in aqueous solution at physiological pH. The effective association constant was determined by the Benesi-Hildebrand procedure to be 760 M-1 at 303 K. This technique requires NMR measurements in the presence of a very large excess of one of the complex components and, since both beta-cyclodextrin and the sodium salt of indomethacin are sparingly soluble in water, NMR spectrometers operating at very high magnetic fields were used. Besides the effective association constant, the Benesi-Hildebrand approach allows a precise determination of all NMR parameters of the pure inclusion complex which may be used for a complete analysis of the geometry of this complex in solution.

Cyclodextrins↗

PubMed1990

Cerebral capillary bed structure of normotensive and chronically hypertensive rats.

In this study cerebral capillary bed structure and the effects of chronic hypertension on these systems have been assessed in 6- to 7-month-old spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats. Capillary diameter (D), profile frequency (Na), volume fraction (Vv), and surface area (Sv) were quantitated by light microscopic morphometry of eight brain areas including the sensorimotor cortex and subfornical organ. Previously presented data from normotensive Sprague-Dawley rats (SpD) of similar age were also compared. Within each of the three rat strains, D, Na, Vv, and Sv varied among brain areas. For the sensorimotor cortex and subfornical organ, capillary profile frequency differed significantly among the three rat strains. In SHR and WKY, there was an inverse correlation between profile frequency and diameter, i.e., as Na increased among brain areas, D decreased. In six brain areas capillary volume fraction and surface area were identical in SHR and WKY, but were lower in SpD. Consistent differences between SHR and WKY were found only for the subfornical organ, which suggests some involvement of this structure in hypertension. Since there were few statistically significant differences between SHR and WKY and many statistically significant differences between the two normotensive strains, cerebral capillary bed structure seems to be independent of arterial blood pressure in most brain areas of these rats.

Animals↗

PubMed1990

Two-way shuttlebox avoidance conditioning and brain NADH in rats.

The effects of amphetamine (1.5 mg/kg) and caffeine (120 mg/kg, 75 mg/kg) on shuttle behavior and on the concentrations of reduced nicotinamide adenine dinucleotide (NADH) of the brain were studied in 56 rats from the perspective of regional brain metabolism. Amphetamine potentiated the shuttle behavior including avoidance responses and response speed, while it increased NADH concentrations in the hippocampus. The low dose of caffeine increased avoidance responses. The high dose of caffeine inhibited avoidance responses, but it had no effect on NADH concentrations in discrete brain regions.

Amphetamine↗

PubMed1990

Quantitative autoradiographic assessment of 55Fe-RBC distribution in rat brain.

A simple in vivo technique of labeling erythrocytes (RBCs) with 55Fe was developed for quantitative autoradiography (QAR). This procedure involved injecting 5-6 ml of [55Fe]ferrous citrate solution (1 mCi/ml) intraperitoneally into donor rats. The number of labeled RBCs reached a maximum at around 7 days and declined very slowly thereafter. Labeled RBCs were harvested from donor rats and used for RBC volume measurement in awake rats. Brain radioactivity was assayed by QAR, which yielded spatial resolution of greater than 50 microns. Tight nearly irreversible binding of 55Fe to RBCs was found in vivo and in vitro. More than 99.5% of the 55Fe in the blood of donor rats was bound to RBCs. Because of this, labeled blood can be taken from donors and injected into recipients without further preparation. The tissue absorption of 55Fe emissions was the same in gray and white matter. Microvascular RBC volumes measured with 55Fe-labeled RBCs agreed with those assayed with 51Cr-labeled RBCs for many, but not all, brain areas. In conclusion, 55Fe-RBCs can be readily prepared by this technique and accurately quantitated in brain tissue by QAR.

Animals↗

PubMed1990

Microlaryngoscopic surgery. An analysis of 300 cases.

Microlaryngoscopic operations were performed on 300 cases of very small lesions of the vocal cord from October 1985 to December 1987 under high frequency ventilation (HFV) and compound venous anaesthesia. 233 cases were followed up for at least 1 month after operation. Among them, 91% recovered completely or improved significantly. The indications, contraindications, anaesthesia, surgical procedures, complications, results, merits and disadvantages of the microlaryngoscopic surgery were discussed in detail.

Adult↗

PubMed1990

Decentralization of superior cervical ganglia attenuates heat stroke formation in rabbits.

The effects of preganglionic decentralization of (sympathetic trunk resection) or post-ganglionic excision (ganglionectomy) of the superior cervical ganglia on cerebral blood flow and the formation of heat stroke were assessed in rabbits. An intravenous isotope method for external measurement of cerebral circulation time was applied to rabbits for determining cerebral blood flow. Heat stroke was induced by exposing animals to a high ambient temperature of 40 degrees C. The occurrence of loss of sensation, decreased muscle tone and unconsciousness was taken as the onset of heat stroke. The results showed that decentralization of the superior cervical ganglia enhanced the cerebral blood flow, whereas ganglionectomy reduced the cerebral blood flow. In addition, the latency for the onset of heat stroke and the survival time after the heat stroke were greatly prolonged by the former surgical procedure, but shortened by the later one. The data suggest that decentralization of the superior cervical ganglia attenuates formation or development of heat stroke by promoting an increase in cerebral blood flow in rabbits.

Animals↗

PubMed1990

Dexamethasone effects on the distribution of water and albumin in cold-injury cerebral edema.

To evaluate the effectiveness of steroids in the treatment of traumatic cerebral edema, we have hypothesized that the distribution of water and RISA is diminished by Dex and have experimentally tested this proposition with the rat model of cortical cold injury. Dex was found to have no effect on the water content of normal brain. The cold injury significantly increased the water content of only the right middle forebrain in untreated rats; in contrast, the increase in water content in the right middle forebrain after cold injury was small and insignificant in Dex-treated rats. Dex diminished the distribution of RISA in the tissue immediately adjacent to the primary lesion but did not affect RISA distribution within the lesion or the remainder of the brain. These findings suggest that steroids do not alter the distribution of water and albumin within cerebral tissue that has been heavily damaged and that steroids do affect these processes in the less traumatized tissue immediately surrounding the primary lesion.

Animals↗

PubMed1990

Effects of dexamethasone on blood flow and volume of perfused microvessels in traumatic brain edema.

We have hypothesized that dexamethasone acts, in part, to reduce the formation and spread of edema fluid by altering CBF and VPM and have tested this proposition by measuring CBF and VPM in treated and untreated rats at several times after cold injury of the cerebral cortex. Both CBF and VPM were markedly decreased within the lesioned cortex. This suggests that the major cause of the fall in CBF was a decrease in the number of perfused microvessels. In untreated rats after cold injury, CBF was not appreciably changed in cortical tissue adjacent to the primary lesion and in contralateral cortex. Dexamethasone may, however, have lowered CBF in these two "normal" brain areas after cold injury. In the ipsilateral corpus callosum adjacent to the lesion, CBF was significantly lowered after cold injury. In the corpus callosum on both sides. CBF tended to be lower in dexamethasone-treated than in untreated rats. Because arterial pressure was similar in treated and untreated rats but CBF was consistently lower in treated rats, dexamethasone may increase the resistance to flow of the blood vessels proximal to the leaky microvessels and reduce the hydrostatic pressure that drives the formation of edema fluid.

Animals↗

PubMed1989

Effect of glucagon on the motility of esophageal smooth muscle.

The functions of glucagon were studied experimentally and clinically. It was found that glucagon (2 x 10(-6)g/ml) could not induce any demonstrable changes in the longitudinal contraction and tonicity of the isolated muscle of the lower esophageal body in 4 rats, nor could cause (0.2 mg iv) significant changes in swallow motility of the esophagus and lower esophageal sphincter (LES) (the esophageal barium transit time, the largest esophageal caliber, the angle of esophageal contraction, the largest LES caliber, and the amount of barium retention at LES) in 6 volunteers under serial-radiography but it (0.2 mg iv) could cause hypomotility of the stomach and duodenum in 19 volunteers. No obvious side-effects were found in 20 volunteers. The recent experimental evidences have suggested that the inhibitory effect of glucagon on the motility of the smooth muscle of the alimentary tract may not be due to its direct action on the receptor, but to its interference with intramural cholinergic neuronal transmission.

Adult↗

PubMed1989

Long-term follow-up of 344 Shanghai psoriatics.

344 patients with psoriasis vulgaris treated in Huashan Hospital, Shanghai were followed up for 7-30 years. 13% of them developed arthralgia and 2% had joint deformities. One patient developed erythroderma due to dexamethasone medication. Internal malignancy occurred in 2 patients (0.58%). The severity of the course of the disease was neither influenced by family history nor alcoholism, but was markedly influenced by the duration of illness and administration of anti-neoplastic drugs.

Adolescent↗

PubMed1989

Annular pancreas. Etiology, classification and diagnostic imaging.

A rare type of annular pancreas, in which the tail of the annular duct is fused with the dorsal pancreatic duct to form the main duct, and its diagnostic imagings of endoscopic retrograde cholangiopancreatography, hypotonic duodenography, computed tomography and ultrasound are described. Annular pancreas is an anomaly embryologically formed by the ventral anlage of the pancreas as the duodenum rotates, mainly due to hypertrophy of the left ventral bud. According to the fusion pattern of the ventral and dorsal pancreatic ducts, annular pancreas can be divided into three types: type I, divisional annular pancreas; type II, branch annular pancreas; and type III, main duct annular pancreas. Endoscopic retrograde cholangiopancreatography, hypotonic duodenography, computed tomography and ultrasound can show the imagings of annular pancreas from different aspects, but the final diagnosis must be based on the evidence of endoscopic retrograde cholangiopancreatography or hypotonic duodenography combined with computed tomography or ultrasound.

Aged↗

PubMed1988

Measurement of basilar artery diameter in dogs: CT evaluation correlated with arteriography.

In this study we have used a computed tomographic (CT) method using profile analysis to measure the diameter of the basilar artery. In a search for a noninvasive and repeatable method to substitute for the traditional arteriography in the evaluation of the degree of cerebral vasospasm, we employed both CT and arteriography to measure the diameter of the basilar artery in eight adult mongrel dogs weighing between 7 and 12 kg. In three of these animals, assessments were made before and after subarachnoid hemorrhage (SAH) induced by injecting autologous arterial blood into the cistern magna. It was found that the basilar artery diameter as evaluated by CT was 47% larger than that measured by arteriography. However, there was a very good correlation (n = 63, r = 0.75, p less than 0.001) between the two methods. This paper presents a new model for the measurement of the basilar artery diameter, one which may also provide a safer method for the evaluation of vasospasm in humans.

Animals↗

PubMed1988