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Biomedical subjects

S Y Lin

Publications and source records attributed to S Y Lin.

At least 217 records · Page 12Linked to original sources
PubMed1994

Propofol modifies recovery from isoflurane-nitrous oxide anesthesia.

A randomized, prospective study was performed to evaluate the hemodynamic changes and recovery characteristics in 60 ASA physical status class I-II unpremedicated patients undergoing gynecological laparotomies with either isoflurane anesthesia only (ISO group) or isoflurane anesthesia followed by propofol infusion (ISO-PRO group). All patients received isoflurane 0.5-1.5% and nitrous oxide (N2O) 66% in oxygen after tracheal intubation. ISO-PRO group (n = 30) received 6 mg kg-1 hr-1 propofol infusion in substitution for isoflurane 25 minutes before the end of surgery. Propofol in ISO-PRO group and isoflurane in ISO group (n = 30) were discontinued 5 minutes before the end of surgery. In both groups, N2O was administered throughout the operation until skin was closed. Hemodynamic measurements were similar between the two groups except at extubation when heart rate and blood pressure were lower in ISO-PRO group. The maximal blood pressure was also lower in ISO-PRO group. In ISO-PRO group, the time required to responsiveness to verbal commands and to orientation were significantly shorter. ISO-PRO group had better Steward's score on arrival at the recovery room and was earlier to get a full score of six. The two groups experienced similar rates of emesis and excitement either two hours or 24 hours postoperatively. We conclude that in relatively long intra-abdominal operations, replacement of isoflurane by propofol infusion 25 minutes before the end of surgery may provide stable maintenance of anesthesia and a faster recovery.

Adult↗
PubMed1994

The effect of low dose propofol for prevention of nausea and vomiting during spinal anesthesia for cesarean section.

In order to investigate the possible antiemetic property of propofol at subhypnotic dosage, fifty patients scheduled for elective cesarean section under spinal anesthesia were accepted into the study. Patients were randomly given intravenous propofol 10 mg (group I) or 1 ml intralipid (group II) after delivery of the infant. Overall incidence of nausea (24% in group I and 40% in group II) and vomiting (16% in group I and 20% in group II) were not statistically different in the two groups. However, onset time to the appearance of nausea and vomiting were longer in group I (14 +/- 5.8 min vs 5.4 +/- 3.6 min). In conclusion, low dose propofol (10 mg) administered during spinal anesthesia for cesarean section failed to reduce the incidence of emesis.

Adult↗
PubMed1994

A case of simultaneous multiple gastric cancers with p53 gene mutation.

Simultaneous multiple gastric cancers are rarely observed in clinical practice, and its association with p53 gene mutation has not been mentioned in any previous reports. We report a case of advanced gastric cancer with two primary lesions in the stomach who received total gastrectomy. Tumor and surrounding normal tissues from the surgical specimen were studied by using polymerase chain reaction-single strand conformation polymorphism analysis, restriction enzyme digestion method and direct sequencing. Point mutations of p53 gene at codon 248 (CGG-->TGG) were found in both primary tumor foci. The patient developed cancerous peritonitis eight months after the operation and expired six months later. This report suggests that p53 gene mutation can occur at an earlier stage in the tumorigenesis of gastric cancer than previously reported and it might be associated with an unusual clinical and pathological presentation.

Aged↗
PubMed1994

A fixational method of tendon transfer in foot surgery.

Tendon transfer has been used for correcting foot deformities and improving foot function in paralytic and spastic foot problems. The traditional fixational method by Cole's pull-out button often induces pressure sores which make the button sink and loosens the transferred tendon, leading to poor surgical results. By using a metal eye cover and pull-out wire instead of button and suture material, the transferred tendon can be firmly fixed. Moreover, the concavity of the metal eye cover is suitable for the arch of the foot that provides a large contact surface & even pressure distribution to prevent the most common complications of the pull-out button method, the pressure sore.

Female↗
PubMed1994

Surgical reconstruction for chronic lateral instability of the ankle.

Chronic lateral instability of the ankle is not uncommon due to improper management of the acute ankle sprain. From July 1987 to December 1991, 45 cases of chronic lateral ankle instability that underwent surgical treatment were followed. The patients included 28 males and 17 females with an average of 24.6 y/o. The time interval from initial injury to surgery ranged from 3 months to 5 years with an average of 9.6 months. All the patients had persistent symptoms in spite of conservative treatment for at least 2 months. The method for reconstruction of the lateral stability of the ankle was the modified Evans' method using part of peroneal brevis tendon. These cases were followed-up for average 25.1 months (range from 13 Ms to 49 Ms). According to Good, Jones & Livingston's criteria for clinical evaluation, 95.6% of the patients obtained excellent or good results. But 11.1% of patients were subjectively unsatisfied and complained of over tightness and limitation of foot inversion. The modified Evans' method has been proven to be easy and effective for reconstruction of the laterally unstable ankle, but it should be performed in the neutral flexion of ankle to prevent an over tight correction of lateral stability.

Adolescent↗
PubMed1994

Simple bacteriological and thin-layer chromatographic methods for determination of individual drug concentrations treated with penicillin-G in combination with one of the aminoglycosides.

For the individual determination of residual drug concentrations in meat when using penicillin-G (PC-G) in combination with one of the aminoglycoside antibiotics, the differentiation of PC-G and the aminoglycoside groups was easily accomplished by incubation of the individual drug with penicillinase (PCase). Each aminoglycoside treated with PCase (50 U/ml) produced a similar clear inhibition zone by the aminoglycoside alone, but PC-G treated with PCase produced no inhibition zone even when a high concentration of 100 microg/ml of PC-G was used on the assay plates seeded with Bacillus subtilis or Micrococcus luteus. Furthermore, these drugs could be distinguished and identified according to their characteristic Rf values and colours by the TLC method using silica-gel 60 F254 plates followed by spraying with various chemical reagents. A solution of n-butanol:acetic acid:water:p-toluenesulphonic acid (3:1:1:0.7) was the best developing solvent for the separation of all the antibiotics.

Aminoglycosides↗
PubMed1993

Physicochemical characterization of 9,10-anthraquinone 2-carboxylic acid.

The physicochemical properties of 9,10-anthraquinone-2-carboxylic acid (AQCA) were investigated by thermal analysis, powder X-ray diffraction pattern, solubility, and partition coefficient. The chemical structure of AQCA was confirmed by the data from UV, Fourier transform IR (FTIR), and NMR analyses. Solubility and partition coefficient data were pH dependent. A new methanolic solvate of AQCA that lost 9.34% of its initial weight from 70 to 100 degrees C was found by thermogravimetric analysis. Sublimation of AQCA occurred at temperatures > 250 degrees C and needle-like crystals (Form I) were formed. The water solubility of AQCA increased with temperature; its heat of solution was 32.7 kJ/mol. A differential scanning calorimetry-FTIR microscopic system correlated a thermal phase transition with structural changes due to loss of methanol from the solvate, and three-dimensional FTIR spectra indicated that the process was complete by 100 degrees C. The kinetics of desolvation and sublimation from each crystal form of AQCA were determined. The activation energy of desolvation of methanol from solvate was 425.8 kJ/mol, and the activation energy of sublimation from Form I or desolvated crystals was 182.7 kJ/mol.

Anthraquinones↗
PubMed1993

Viscoelasticity of anionic polymers and their mucociliary transport on the frog palate.

The influence of formulation variables on the rheology of polyanionic formulations and the relationships between viscoelastic properties and mucociliary transport rate were investigated. Polymeric samples were oscillated from 0.001 to 5 Hz using either a "cone and plate" or a "coaxial cylinder" measuring system. The mucociliary transport rates of polymeric samples were determined and compared movement of charcoal powder on the frog palate. For the linear polymeric solutions, sodium carboxymethylcellulose and sodium alginate, the elastic modulus (G') increased with increasing amplitudes during frequency scan. However, the G' or viscous modulus (G'') of partially cross-linked polyacrylic acid (cPAA) samples did not change significantly under oscillation. Both G' and G'' of cPAA samples were significantly influenced by the amount of salt present in the formulation. The rheology of 2% (w/w) cPAA in 90:10 (w/w) propylene glycol:alcohol changed from a viscous fluid to a coarse suspension after neutralization. The pH increased gradually when the nonaqueous formulation reacted with water and the maximum dynamic moduli were obtained after incorporating 20% (w/w) water in the formulation. A negative correlation was found between the G' of linear polyanionic samples and the relative transport rate. However, the lowest mucociliary transport rate was observed when the loss tangent (G''/G') was around 0.4-0.5.

Acrylic Resins↗
PubMed1993

Mutation analysis of K-ras oncogenes in gastroenterologic cancers by the amplified created restriction sites method.

A rapid, simple, and nonradioactive method for diagnosing point mutations of c-K-ras oncogenes in gastroenterologic cancers is described. This method involved the selective amplification of DNA fragments from cancer tissues of surgical specimens with specific oligonucleotide primers, followed by digestion with restriction enzymes that recognized artificially created or naturally occurring restriction sites. To detect codon 12 mutations, an artificial Msp I site was created by introducing a single nucleotide mismatch into the 5' mutagenesis primer. Using a similar approach, an Hae III site was created to detect codon 13 mutations. Bal I and MBo II sites were used to detect codon 61 mutations. A total of 61 gastroenterologic cancer cases were studied. Of 35 cases of colorectal cancer, 7 showed mutations: 6 at codon 12 and 1 at codon 13. In 1 of 2 cases of cholangiocellular carcinoma, point mutation at codon 12 was found. One case of duodenal cancer showed point mutation at codon 12. No mutations were found in the cases of hepatocellular carcinoma (4), gastric cancer (12), esophageal cancer (3), or pancreatic cancer (2).

Amino Acid Sequence↗
PubMed1993

Comparison of hepatitis C virus strains obtained from hemodialysis patients.

To understand what genotypes of hepatitis C virus (HCV) exist in Taiwan, we chose the non-structure 5 (NS5) region of the HCV genome for the target area of reverse transcription-polymerase chain reaction (RT-PCR) to detect HCV RNA from sera of hemodialysis patients. Of 39 serum samples which were positive for the HCV antibody among 87 samples from hemodialysis patients, 12 (antibody against HCV core protein, OD > 2) were examined by the RT-PCR. The plasmid pUC19 was used to clone HCV cDNAs in the NS5 region (401 bp) derived from 11 serum samples which were positive for HCV RNA. Sequence analyses of individual clone of these 11 amplified cDNA fragments were performed. Dr. Cha's classification (16) suggested that two genotypes of HCV were found in these serum samples; type II (2/18.2%) and type III (9/81.8%). Our study indicates also that NS5 is an adequate target region to differentiate HCV strains derived from different patients in the same hospital. The analysis of the amplified cDNA in the NS5 region of the HCV genome will therefore provide suitable information to perform a molecular epidemiological study on the transmission routes of this important virus infection.

Amino Acid Sequence↗
PubMed1993

"Hot spots" mutation analysis of p53 gene in gastrointestinal cancers by amplification of naturally occurring and artificially created restriction sites.

We developed a rapid, simple method to detect "hot spot" point mutations of the p53 gene. A DNA fragment from cancer tissue of a surgical specimen was selectively amplified with specific oligonucleotide primers and then digested with restriction enzymes that recognized artificial or naturally occurring restriction sites. To detect mutations in codons 273 and 245, we created artificial Bst U1 and BgI I sites by introducing a single nucleotide mismatch into the respective mutagenesis primers. We used the naturally occurring restriction sites of Msp I, Hae III, and Hha I to detect mutations in codons 248, 249, and 175, respectively. In 74 cases of gastrointestinal cancer, 5 of 35 colorectal cancers showed mutations; 1 of 15 cases of gastric cancers showed mutation; and 1 of 24 hepatocellular carcinomas showed mutation. This nonradioactive method is an accurate and clinically useful way to detect hot-spot point mutations of the p53 gene in gastrointestinal cancers.

Base Sequence↗
PubMed1993

Hemodynamic responses to surgical stimuli in brain-death organ donors.

Though spinal reflexes have been described in experimental brain-death animals, no documentation has been previously provided for human. The hemodynamic responses to surgical stimuli have been investigated here in eight brain-death organ donors. Baseline systolic blood pressure, diastolic blood pressure, and heart rate in observed patients were 99 +/- 15 mmHg, 61 +/- 13 mmHg, and 105 +/- 22 beats/min respectively. After skin incision, these parameters elevated maximally to 130 +/- 23 mmHg, 74 +/- 17 mmHg, and 119 +/- 18 beats/min (p < 0.05). Either spinal reflex arcs or adrenal medullary stimulation, or both, have been speculated to possibly play the role in these hemodynamic responses. However, the existence of such responses should not invalidate the diagnosis of brain death.

Blood Pressure↗
PubMed1993

Ultrasound imaging aids infraclavicular brachial plexus block.

Infraclavicular approach to the brachial plexus provides adequate anesthesia of the entire arm. Local anesthetics can be deposited over cords and branches of brachial plexus above the formation of musculocutaneous and axillary nerves. The approach can also easily block ulnar segment of medial cord and intercostobrachial nerve, which helps preventing tourniquet pain. However, distance to the plexus is deeper than the other approaches so that current blind method using anatomical landmarks requires anesthesiologists' delicate manipulation and experience. Through ultrasonography, the location of subclavian artery, as an anatomical landmark, can be easily identified. It is then very easy and safe to perform infraclavicular brachial plexus block. Our new method showed 89% (n = 9) successful rate. The time for the block was 4.2 +/- 1.5 min and there was an average of 3.2 +/- 0.6 needle penetrations. Thirty three percent (n = 3) had subclavian artery been punctured without formation of hematoma clinically. No patient had clinical postoperative pneumothorax.

Adult↗
PubMed1993

[The effects of ketamine, propofol and nitrous oxide on visual evoked potential during fentanyl anesthesia].

To evaluate the effects of ketamine, N2O, propofol on visual evoked potential (VEP) during fentanyl anesthesia, 14 patients undergoing transphenoid pituitary dissections were studied. Visual stimulation was done by using the goggles with red light diodes through closed eyelids and responses were recorded in one channel montage, Cz against Oz. The stimulus frequency was 1.9 flashes/sec. The VEPs were recorded from skin incision until the opening of the dura. For comparison, the preanesthesia to anesthesia values were determined. The ratio for N2 (N75) latency were 100.5 +/- 13.9% in ketamine group, 104 +/- 3.5% in N2O group, 100.5 +/- 4.2% in propofol group. The ratios for P2 (P100) latency were 97.45 +/- 5.7% in ketamine group, 101.9 +/- 3.5% in N2O group, 96.8 +/- 5.5% in propofol group. For N2P2 amplitude, the ratios were 36.3% +/- 31.4% in ketamine group, 138.5 +/- 58.0% in N2O group, 80.8 +/- 42.2% in propofol group. The percentage of inadequate recordings were 2.5 +/- 4.3% in ketamine group, 19.2 +/- 2.2% in N2O group and 20.6 +/- 16.0% in propofol group. The percentage of false positive results were 0 +/- 0% in ketamine group, 9.8 +/- 19.9% in N2O group, 12.7 +/- 13.2% in propofol group. Satisfactory anesthesia was achieved in all groups except for ketamine group which required additional medications for elevated blood pressure and intracranial pressure, and postoperative nausea and vomiting. It is concluded that there was great variability of VEP during anesthesia and surgery. Amplitude rather than latency changes were observed during anesthesia combined with fentanyl.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Sequence analysis of nucleocapsid and partial envelope genes of the hepatitis C virus derived from an aboriginal asymptomatic carrier.

Two overlapping cDNA fragments of the 5'-terminal region of the hepatitis C virus (named as HCV-B) were cloned by reverse transcription-polymerase chain reaction (RT-PCR). The consensus nucleotide sequence of the 1101 nucleotide length was constructed from the sequences of at least three independent clones of each one of these two amplified overlapping HCV cDNA fragments. By comparison with other HCV strains isolated from different countries, the 5' non-coding region was almost identical, with only 1 difference in 90 nucleotides, and the homology of the putative nucleocapsid gene was found to be quite conservative, with a similarity of 90-96% and 96-97% at the nucleotide and amino acid levels, respectively. The homology of the down-stream region which encodes a putative envelope protein showed a low degree of identities (71.5% and 76.7% compared with American HCV-1 strain) at the levels of nucleotide and amino acid. On the other hand, it was similar to the Taiwanese HCV-T strain and the Japanese major J1 strain; the homology was about 93% at both levels of nucleotide and amino acid. This finding led to a conclusion that the HCV-B strain is closely related to the major HCV genotypes as HCV-J1 and HCV-T, isolated in Asian area.

Amino Acid Sequence↗
PubMed1993

Validity and feasibility of nasopharyngeal end-tidal carbon dioxide tension monitorings: a novel approach in spontaneous breathing patients.

Conventional end-tidal CO2 (Pe'CO2) monitoring is difficult and impractical in nonintubated patients who are either sedated or anesthetized while spontaneous respiration is maintained. An alternative technique using nasopharyngeal end-tidal carbon dioxide tension (PNe,CO2) has been developed. The present study evaluates the feasibility and validity of PNe,CO2 as a reliable respiratory monitoring method. Sixty patients in ASA class status I or II and scheduled for elective surgery were divided into two groups. In group 1 (n = 30), conventional Pe'CO2 was used in intubated patients under general anesthesia. In group 2 (n = 30), PNe,CO2 monitoring was used in patients under regional anesthesia with spontaneous respiration maintained. A 12 FG suction catheter, connected to the sampling tube of a CO2 analyzer, was inserted via the nasal airway to within 1 cm of the nasopharyngeal orifice. Arterial blood gas (PaCO2) was sampled 25 minutes after the operation began, Pe'CO2 (group 1) and PNe,CO2 (group 2) were recorded simultaneously. In both groups, PaCO2 was highly correlated with Pe'CO2 (r = 0.6938) and PNe,CO2 (r = 0.8613). The difference between the two values, (a-e')PCO2 = 0.35 +/- 0.33kPa and (a-Ne')PCO2 = -0.1 +/- 0.51kPa, indicates that PNe,CO2 is more closely correlated to PaCO2 than conventional Pe'CO2. The reduced (a-Ne')PCO2 in group 2 may be explained by CO2 rebreathing and a reduced respiratory deadspace during anesthesia and spontaneous breathing. Interestingly, 60% of the (a-Ne')PCO2 measurements were negative values, suggesting that PNe,CO2 and a spatial V/Q mismatch is caused by sedation; higher CO2 production and CO2 rebreathing may explain the results.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗