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Biomedical subjects

S S Lin

Publications and source records attributed to S S Lin.

At least 109 records · Page 6Linked to original sources
PubMed1991

Concanavalin A: a tool to investigate neuronal plasticity.

Neuronal plasticity is the ability of neurons to alter their cellular properties in response to changes in their environment. These changes are typically triggered by the binding of specific ligands, such as neurotransmitters, growth factors or other neuromodulators, to receptors on the neuronal membrane surface. Since the extracellular domains of many of these receptors are glycosylated, they can also be bound by lectins--proteins with high affinity binding sites for polysaccharides. Different lectins have different affinities for various sugar residues. This feature has made lectins useful in the investigation of the regional localization and relative mobility of different classes of glycosylated membrane receptors, and in the subsequent purification of the receptors. This article reviews some of the different kinds of neuronal plasticity produced by the plant lectin concanavalin A (Con A), such as enhancement of neurite outgrowth, modulation of neurotransmitter responses, and alteration in the specificity and strength of synaptic connections.

Amino Acid Sequence↗
PubMed1991

Effect of stresses before slaughter on changes to the physiological, biochemical and physical characteristics of duck muscle.

1. This experiment was designed to study the effects of fasting and enforced exercise on the physiological, biochemical and physical characteristics of duck muscle. 2. Sixty 75-d-old male ducks weighing 3.0 +/- 0.2 kg were assigned to three treatments: a control, and an 8 and 24 h fast plus enforced exercise for 10 min. The ducks were then sacrificed and the carcass stored at 4 degrees C for 24 h. 3. Although the pH and serum lactate contents gradually increased with fasting time the responses were not significant. The ultimate pH was elevated and the lactate of breast and thigh muscles was lower in stressed birds. 4. The activity of lactic dehydrogenase was significantly increased by the stress, and the activities of creatine phosphokinase and alkaline phosphatase were also increased slightly. However, no effect was found on the ATPase activity of the myofibrillar protein of either breast or thigh muscle as a result of the stress. The ATPase activity of myofibrillar protein of breast muscle significantly increased with storage time. 5. The extractability of myofibrillar protein increased with storage time for all treatments. The SDS-PAGE patterns of myofibrillar proteins were also studied. 6. Consequently DFD-like muscle was observed in the breast and thigh muscles of ducks which had been stressed.

Adenosine Triphosphatases↗
PubMed1991

Identification of human papillomavirus DNA sequences in peripheral blood mononuclear cells.

Polymerase chain reaction (PCR) was used to amplify and identify the presence of the DNA of human papillomavirus (HPV) types 6, 11, 16, and 18 in peripheral blood mononuclear cells (PBMCs) of women with and without urogenital HPV infections. HPV DNA of various types was found in PBMCs of 13 of 25 (52.0%) patients with urogenital HPV infections and in none of the 19 control subjects who are free of urogenital HPV infections. The presence of HPV DNA in PBMCs may impair the immunologic functions of the lymphocytes and play a role in the epidemiology of HPV infections and the pathogenesis of HPV-induced diseases.

Base Sequence↗
PubMed1991

The effect of soluble complement receptor type 1 on hyperacute xenograft rejection.

In the guinea pig-to-rat model of hyperacute xenograft (Xg) rejection, the effect of complement inhibition using systemically administered soluble complement receptor type 1 (sCR1) on discordant cardiac Xg survival was investigated. In PBS-treated control Xg recipients (n = 13), hyperacute rejection was rapid, with a mean Xg survival of 17 +/- 4 min. Therapy with sCR1 prolonged survival of cardiac Xgs in a dose-dependent manner. A 3 mg/kg bolus of sCR1 (n = 4) prolonged Xg survival to 64 +/- 29 min (not significant). Increasing the sCR1 dose to 5.9 mg/kg (n = 4) significantly delayed Xg rejection to 71 +/- 17 min (P-0.026, log-rank test vs. control). In 10 recipients treated with 15 mg/kg sCR1, mean Xg survival was further prolonged to 189 +/- 36 min (P-0.0004) with no adverse effects. While 2 of 8 recipients receiving 60 mg/kg sCR1 died with functioning Xgs at 30 and 300 min due to anastomotic bleeding, Xg survival averaged over 12 hr (747 +/- 100 min, P-0.0004) in the remaining 6 recipients. sCR1 administration significantly inhibited serum complement activity in a parallel dose-dependent fashion, with the 60 mg/kg dose reducing complement activity by 95 +/- 1 and 96 +/- 1% five and 30 min following Xg reperfusion, respectively. Immunofluorescence microscopy revealed rat IgM bound to all cardiac Xgs in control as well as sCR1-treated recipients. In addition, serial histologic examination of cardiac Xgs harvested within 21 min of graft reperfusion revealed occlusive platelet aggregates within the coronary vessels as well as interstitial hemorrhage and myocardial necrosis in Xgs from control recipients, all of which were only minimally present in Xgs from recipients treated with sCR1. These studies show that complement inhibition with sCR1 significantly delays hyperacute cardiac Xg rejection in this discordant model and may be an important component in a therapeutic protocol for xenotransplantation.

Animals↗
PubMed1991

A comparison of umbilical venous blood levels of neuropeptide Y and catecholamines between cesarean section and normal spontaneous delivery.

This study was designed to determine the presence and different levels of placental neuropeptide Y (NPY) in women at parturition between normal spontaneous delivery (NSD) and cesarean section (C/S) under spinal anesthesia and to compare it with the level of catecholamines. Umbilical vein plasma levels of neuropeptide Y and catecholamines of the placental cord were measured at delivery in 40 parturient women who were divided into two groups, with 20 patients in each. NSD group underwent vaginal delivery without the presence of intrapartum fetal distress. C/S group received elective cesarean section (C/S) under spinal anesthesia. The results showed that umbilical vein level of NPY in NSD patients was significantly less than C/S patients (160.32 pg/ml vs 346.25 pg/ml, p less than 0.01). But for catecholamines levels, C/S group were significantly less than that of NSD group.

Anesthesia, Obstetrical↗
PubMed1991

[Clinical and experimental study on shenghong kangyan su in treating 144 cases of pelvic inflammation with blood stasis syndrome].

Using the method of clearing up heat and resolving stasis, the authors treated 144 cases of pelvic inflammation with blood stasis syndrome (BSS) with Shenghong Kangyan Su. The total effective rate was up to 97.92%, cure rate up to 68.75%, without toxicity and side effects. Clinical and experimental study showed that the crux of pelvic inflammation with BSS had some relations with microcirculation obstruction. Inflammation may cause microcirculation obstruction and blood stasis, and is one forms of BSS. Therefore dull purple-tongue, undertongue vein dilated, abdominal pain in lower-part, pathologic mass can be regarded as the basis of diagnosis of pelvic inflammation with BSS The drug of clearing heat and resolving status has the functions of anti-inflammation, anti-pain, diminishing the obstruction of microcirculation, particularly in speeding up the blood flowing, lowering the aggregation of erythrocyte, P less than 0.001.

Adolescent↗
PubMed1990

The detection of Gardnerella vaginalis DNA sequences in uncultured clinical specimens with cloned G. vaginalis DNA as probes.

Cloned Gardnerella vaginalis DNA were selected from a plasmid DNA library constructed with partially restriction endonuclease Hind III-digested genomic DNA of G. vaginalis to serve as DNA probe in detecting G. vaginalis. The level of detection was determined to be approximately 10,000 cells by slot-blot DNA hybridization. This probe DNA will not cross-hybridize with DNA of a number of non-Gardnerella micro-organisms commonly found in female genital tract. The DNA probe-based hybridization test may become a useful tool for the identification of G. vaginalis in uncultured clinical specimens.

Blotting, Southern↗
PubMed1990

Study of plasma neuropeptide Y (NPY) and catecholamines levels during spinal anesthesia.

Plasma levels of neuropeptide Y (NPY) and catecholamines were investigated during spinal anesthesia. Ten ASA physical status I-II patients were studied after obtaining institutional approval and informed contents. All patients were free from endocrine and metabolic disease underwent elective low risk operation. No premedication was given before operation. Spinal anesthesia was performed on lateral position from L3-4 interspace with 15 mg tetracaine without added epinephrine. The analgesic level was about at T6 dermatone. Blood samples were obtained from radial artery catheter, 15 minutes before spinal anesthesia and 5', 15', 30', 60', 120', during operative period and 30' after operation in postanesthesia recovery room. The results showed that there were significant elevation in plasma level of NPY during spinal anesthesia compared with the level before anesthesia. However, no statistically significant changes of plasma catecholamines were found.

Adolescent↗
PubMed1990

Study of plasma neuropeptide Y (NPY) and catecholamines levels during isoflurane anesthesia.

Twelve ASA physical status I-II patients were studied after obtaining institutional approval and informed contents. All patients were free from endocrine and metabolic disease undergoing elective low risk operation. Pethidine 1 mg/kg i.m. and benzodiazepine 0.01 mg/kg p.o. were given as premedication one hour before anesthesia. Anesthesia was induced with thiopental 4 mg/kg and succinylcholine 1.5 mg/kg for tracheal intubation. Anesthesia was maintained with 2% isoflurane and 50% N2O in oxygen. Ventilation was controlled and adjusted to maintain an end-tidal CO2 concentration of 25-35 torr. Atracurium 0.4 mg/kg was given as muscle relaxant. Blood samples were obtained from radial arterial catheter, 15 minutes before induction of anesthesia and 5 min after anesthesia, 15 min, 30 min, 60 min during operation and 30 min after operation in postanesthesia recovery room. The results showed that there were no statistically significant changes in plasma levels of NPY and catecholamines during operation underwent isoflurane anesthetic technique. This result indicates that isoflurane anesthesia can block the plasma NPY as well as catecholamines during surgical stress.

Adult↗
PubMed1989

Studies of blocking mechanisms of carbachol-induced polyphosphoinositide turnover in rat cortical synaptosomes by neuroactive drugs.

1. The incorporation of 32Pi into 4 phospholipids of rat cortical synaptosomes was altered in the presence of carbachol (1 mM), viz. a decrease of phosphatidylinositol-4,5-bisphosphate and phosphatidyl-4-phosphate by 34 and 21%, and an increase of phosphatidylinositol and phosphatidic acid by 52 and 96% of basal controls respectively. 2. The IC30 values calculated from the dose-response curves for drugs affecting carbachol-induced 32Pi incorporation into these phospholipids, and [3H]QNB binding to the cortical synaptosomes were similar for the typical antimuscarinic agents (i.e. atropine, pirenzepine and trihexyphenidyl), and tricyclic antidepressants (i.e. amitriptyline, doxepin and imipramine) studied. 3. The IC30 values obtained for drugs affecting carbachol-induced 32Pi incorporation into these phospholipids, and high potassium-induced 45Ca2+-uptake by this preparation were similar for neuroselective calcium channel blockers (i.e. cinnarizine and flunarizine) studied. 4. Our results suggest that the neuroactive drugs studied can either act at, or beyond the receptor level, perhaps on the availability of calcium ion, to block carbachol-induced polyphosphoinositide turnover in rat cortical synaptosomes.

Animals↗
PubMed1989

Concanavalin A modulates a potassium channel in cultured Aplysia neurons.

A novel 100 pS K(+)-selective ion channel is frequently observed in cell-attached membrane patches from cultured Aplysia neurons. The activity of this channel is moderately voltage-dependent, but channel openings are rare and brief even when the patch is strongly depolarized. However, the activity of the channel is increased dramatically by the addition of the lectin concanavalin A (Con A), to the patch pipette. The channel is also activated by Con A in the bathing medium, suggesting that the lectin's action is via an as yet unidentified intracellular second messenger. In the one single-channel patch studied, Con A had no effect on the channel mean open time; rather it decreased the average duration of the long closed times between bursts of openings. Thus Con A increases either the open probability of single channels, the number of functional channels in the patch, or both. The functional significance of the Con A-induced modulation of K+ channel activity remains to be determined.

Animals↗
PubMed1989

Study of plasma neuropeptide Y and catecholamine levels during high dose fentanyl anesthesia.

Ten ASA physical status I-II patients were studied after obtaining institutional approval and informed consent. All patients were free from endocrine and metabolic disease undergoing elective low risk operation. They were premedicated with pethidine 1.0 mg/kg intramuscularly and diazepam 0.1 mg/kg orally one hour before anesthesia. Anesthesia was induced with thiopental 4 mg/kg and succinylcholine 1.5 mg/kg for tracheal intubation. Anesthesia was maintained with intermittent intravenous injection of fentanyl (50-100 micrograms/kg) and inhalation of N2O-O2 (50%). Ventilation was controlled during surgery. Atracurium (0.4 mg/kg iv) was given for muscle relaxation when needed. Blood samples were obtained from the radial artery 15 min before induction of anesthesia and 5 min after intubation, 15 min, 30 min, 60 min, 120 min during operation and 30 min after operation. Neuropeptide Y (NPY) was determined by radioimmunoassay, catecholamines were determined by radioenzymatic method using CAT-A-KIT (Amersham). Statistical analysis was performed using Student's t-test for paired and unpaired samples. P values less than 0.05 were considered significant. Naloxone 0.4 mg was given by iv at the end of operation in all of the patients to establish adequate spontaneous respiration. The results showed that the plasma NPY was significantly decreased under high dose fentanyl as well as catecholamines.

Adolescent↗
PubMed1989

Effects of pH of cerebrospinal fluid and local anesthetic on the success rate of spinal anesthesia.

Forty-three ASA physical status I-II adult patients, receiving spinal anesthesia for lower abdominal or lower limb surgery, were allocated randomly to two groups. Group 1 patients (n = 21) were given heavy bupivacaine 12 mg and group 2 patients (n = 22) were given tetracaine 12 mg in 2.5 mL of 10% dextrose. Spinal anesthesia was performed in the lateral decubitus position the at L 3-4 interspace with a 25-G spinal needle. Radial artery blood samples were collected before and after spinal anesthesia fpr pH measurement using a NOVA Biomedical machine; CSF samples were collected before and after injection of local anesthetic, and local anesthetic was also collected at the same time, for pH measurement using a Radio pH meter. The time from injection to maximal cephalad spread of analgesia and level of spinal analgesia were measured by the pin-prick method. The result was regarded as a failure if pain sensation still existed at the level of the operation site after spinal anesthesia. There were 1 failure case in the bupivacaine group and 2 failures in tetracaine group. The pH of CSF and local anesthetic in these failures were compared with those in effective cases, and the results showed that there was no significant relationship between the pH value of CSF and the local anesthetic drug.

Adolescent↗
PubMed1988

The detection of mycobacterial DNA sequences in uncultured clinical specimens with cloned Mycobacterium tuberculosis DNA as probes.

A plasmid DNA library was constructed from restriction endonuclease digested genomic deoxyribonucleic acid (DNA) of a virulent strain of Mycobacterium tuberculosis isolated from sputum of a patient. The sensitivity and specificity of two of the cloned DNA fragments in detecting M. tuberculosis and its related DNA sequences were analysed by DNA-to-DNA hybridization. The level of detection was determined to be 50 picograms of M. tuberculosis DNA, which is approximately equivalent to 10,000 mycobacterial genomes. These two M. tuberculosis DNA probes did not cross-hybridize to DNA of non-mycobacterial origin, nor with DNA from 9 out of 11 other mycobacterial species. Mycobacterial DNA sequences could be detected in 134 of 441, or 30.4%, of various types of uncultured clinical specimens from 365 patients by the DNA probes, whereas traditional culture method showed only a 19.0% positivity rate for the same specimens (p less than 0.001). The overall sensitivity and specificity of the DNA probes in detecting M. tuberculosis are 90.5% and 83.8% respectively. The DNA hybridization test may become a useful tool for the early and rapid determination of mycobacterial infection in uncultured clinical specimens.

Autoradiography↗
PubMed1987

Concanavalin A alters synaptic specificity between cultured Aplysia neurons.

Factors that regulate synaptic specificity were investigated with Aplysia buccal and bag cell neurons in primary cell culture. In the presence of fetal calf serum electrical synapses are formed between buccal-buccal or bag-bag cell pairs, but not between buccal-bag cell pairs. Instead, buccal neurons make inhibitory chemical synapses on bag cells. However, in the presence of nanomolar concentrations of the lectin concanavalin A this pattern changes, such that more than 75 percent of buccal-bag pairs exhibit electrical synapses and the frequency of occurrence of buccal-bag chemical synapses is reduced. Such changes in synaptic specificity may be important in determining the types of synapses formed during neuronal development and neurite regeneration.

Aplysia↗