Search PubMed⌕ Search

Biomedical subjects

C Lai

Publications and source records attributed to C Lai.

At least 91 records · Page 5Linked to original sources
PubMed1991

An extended family of protein-tyrosine kinase genes differentially expressed in the vertebrate nervous system.

We have used PCR to identify 13 novel protein-tyrosine kinase genes (tyro-1 to -13), six of which (tyro-1 to -6) are preferentially expressed in the developing vertebrate nervous system. The tyro-2 and tyro-9 genes encode kinase domains that exhibit strong amino acid sequence similarity to the equivalent regions of the receptors for EGF and FGF, respectively, and may encode novel receptors for these or related polypeptide ligands. The tyro-1 to -6 genes are all expressed during central nervous system neurogenesis and exhibit distinct and highly regionalized patterns of expression in the adult brain. Together with recent studies in invertebrates, these data are consistent with the hypothesis that protein-tyrosine kinases play a central role in neural development.

Amino Acid Sequence↗
PubMed1991

Bone-inducing activity of mature BMP-2b produced from a hybrid BMP-2a/2b precursor.

The human osteoinductive proteins BMP-2a and BMP-2b have been cloned and expressed in mammalian cells. In order to improve expression levels we examined the role of the proregion in assembly and export. Use of the BMP-2a proregion combined with the mature region of BMP-2b leads to dramatically improved expression of mature BMP-2b. Mature BMP-2b has been purified to near homogeneity from the BMP-2a/2b hybrid, and its structural properties and biological activity determined. Recombinant mature BMP-2b homodimer elicits bone formation in vivo.

Amino Acid Sequence↗
PubMed1991

[Effects of benazepril, a new ACE inhibitor, in effort angina pectoris].

The aim of this study was to evaluate the anti-ischemic efficacy of 2 different doses of benazepril (B), a new ACE-inhibitor, 10 and 20 mg, given per os. Fifteen male patients gave informed, written consent; they were aged 40-67 years, with stable effort angina pectoris and were randomly given, in double-blind condition, a tablet containing B 10 mg, B 20 mg or placebo (PL), once a day, according to a 3 x 3 latin square design. Bicycle exercise tests were performed on the same day, 2 and 10 hours after the last drug intake. B 10 mg and B 20 mg, in patients with stable effort angina, compared to placebo, increased ischemic threshold and decreased ischemic ST depression at maximal work, after 2 hours but not after 10 hours. In conclusion B 10 mg and B 20 mg showed anti-ischemic activity 2 hours after drug intake.

Adult↗
PubMed1991

[Transdermal nitroglycerin in stable effort angina. I. Therapeutic effect and duration of the action of a single dose. Comparison with placebo and isosorbide dinitrate].

To assess the efficacy of 2 doses of a transdermal system for nitroglycerin, 10 and 20 mg (NTTS 10 and NTTS 20) and isosorbide dinitrate 40 mg (ISD 40) on exercise tolerance test, a double-blind within patients placebo (PL) controlled study was performed: 12 male patients, aged 47-71 years, with stable effort angina, with fixed ischemic threshold, received, according to a 4 x 4 latin square design, NTTS 10, NTTS 20, ISD 40 and PL, at 7.00 am on 4 consecutive days. Bicycle exercise tests were performed 4 and 12 hours post-dosing, after which the systems were removed. NTTS 10 and 20 and ISD 40 increased significantly ischemic threshold, anginal threshold and decreased maximal ST depression at the fourth hour. Only NTTS 10 and NTTS 20 showed antiischemic activity after 12 hours. During exercise, at the fourth and twelfth hour, there was no significant difference in rate-pressure product between placebo and NTTS 10 and 20 and ISD 40. Therefore the antiischemic activity of these drugs was not related to a decrease of myocardial oxygen consumption. In conclusion, in comparison with PL, NTTS 10, 20 and ISD 40 had antiischemic and antianginal activity at the fourth hour, while at the twelfth hour this activity was observed only after NTTS 10 and 20, without differences between the 2 doses.

Administration, Cutaneous↗
PubMed1991

[Transdermal nitroglycerin in stable effort angina. II. Administration of continuous high doses and alternate high-low doses. Absence of tolerance].

Aim of this study was to evaluate the efficacy of 2 different schedules of nitroglycerin (N), given by means of transdermal therapeutic system (TTS): continuous (20 mg patch at 8.00 am and at 8.00 pm NTTS/c) and high/low doses therapy (20 mg patch at 8.00 am and 10 mg at 8.00 pm NTTS/a), respectively. Eighteen volunteers, gave informed, written consent; male patients, aged 57 +/- 2 years, with stable effort angina pectoris, were randomly given, in double-blind condition, NTTS/c, NTTS/a or placebo (PL), each for 1 week period, according to a 3 x 3 latin square design. Bicycle exercise tests were performed on the first and on the last day of each period of the study, 12 hours after the last patch. NTTS/c and NTTS/a increased ischemic threshold and decreased the ischemic depression ST at maximal common work, compared to placebo, without differences between tests performed at 1 and 7 day. In conclusion, NTTS/a showed antiischemic activity after 7 days, so no tolerance was observed in those patients.

Administration, Cutaneous↗
PubMed1991

Late-onset acid maltase deficiency in a Chinese girl.

Late-onset acid maltase deficiency is a rare disorder. We describe a nineteen year old Chinese girl who presented with diarrhoea, limb-girdle weakness and respiratory failure requiring mechanical ventilation. Electromyography showed polyphasic potentials and myotonic discharges. Muscle biopsy revealed features characteristic of acid maltase deficiency. Assay of acid alpha-glucosidase in cultured skin fibroblasts confirmed the diagnosis. Supportive treatment with nocturnal intermittent positive pressure ventilation via a nasal mask and dietary supplementation with branched-chain aminoacids proved effective in this patient. The cause of diarrhoea remained uncertain. This is the first documented case of acid maltase deficiency in Chinese adult.

Adolescent↗
PubMed1991

[A new anti-ischemic drug for the treatment of stable effort angina pectoris: nicorandil. Comparison with placebo and isosorbide-5-mononitrate].

The aim of this study was to investigate antianginal and antiischemic activity and tolerance of a new nitrate derivative, nicorandil (N). This research has been carried out in 18 patients, aged 47-70 years, suffering from stable effort angina with fixed ischemic threshold. The study started with 10 days of washout, during which the patients exercised twice on bicycle to verify the reproducibility of the test. Then, they took N or isosorbide-5-mononitrate (ISM) for 14 days according to a double blinded cross-over balanced study. Between the 2 periods patients took placebo (PL) for 14 days. In the first day and in the last day of each period, 2 hours after the last drug intake, patients performed a stress test on bicycle. Like ISM, N significantly increased, versus PL, 1 mm of ST depression time (ischemic threshold) in the first and in the last day, without differences between the 2 drugs and between the days. Moreover, ST depression was significantly lower at maximal common work (MCW) versus PL. The rate-pressure product was not different from PL after N and ISM at maximal common work, but is was increased at the ischemic threshold. In conclusion, like ISM, N has shown antiischemic activity in patients suffering from stable angina pectoris on effort with fixed ischemic threshold. After 14 days of treatment there was no evidence of tolerance. The activity of N seems essentially due to an increase of coronary blood flow to ischemic zones.

Aged↗
PubMed1991

[What have we learned from large trials?].

Clinical trials, during myocardial infarction, showed the importance of thrombolytic therapy on coronary patency, to improve left ventricular function, to reduce early and late mortality. Since the efficacy of thrombolytic therapy is now well established, most clinical trials were made to compare the efficacy of SK, rt-PA and APSAC and to evaluate concomitant drugs. Recanalization and coronary patency, reocclusion and incidence of side effects, left ventricle function's improvement and lowered mortality have been used to assess drugs' activity. At the moment the efficacy of three thrombolytic drugs seems to be the same. So the drug's choice is related not to drug's efficacy but to side effects of the drugs. Concomitant intravenous heparin therapy is now under study; utility of this therapy is shown by its theoretical assumptions and by clinical trials results. Large clinical trials are working to extend our knowledge, improving the patients' management in our every day clinical practice. Furthermore, large trials do not replace but go together with studies performed on few patients, whose results often give advance notice of those of large ones.

Clinical Trials as Topic↗
PubMed1990

Propionyl carnitine in stable effort angina.

The aim of this study was to investigate the anti-ischemic activity of propionyl carnitine (PC) in 18 informed, volunteer male patients, aged 37-70, suffering from a typical stable effort angina. The study design was randomized, balanced, crossover, and double blinded. The study lasted 75 days. In the first 15 days of washout the patients performed two maximal symptom-limited bicycle tests to verify the repeatability of the parameters examined. Then one group received PC for 30 days 500 mg three times a day, and the other group received placebo (PL) three times a day. At the end of 30 days the groups exchanged treatments. At the end of each period, 2 hours after the last oral administration, the patients performed a maximal symptom-limited bicycle exercise test with increased loads of 10 watts/min. No significant differences were observed between the two tests performed during the wash-out period, for a 1 mm ST-segment depression time, for the time to the end of exercise, and for the rate x pressure product at the same experimental time. The oral administration of PC in coronary patients increased both the 1 mm ST-segment depression time and the time to the end of exercise. Furthermore, the drug reduced the ischemic depression of ST at maximal common work and at maximal work. After PC, the rate x pressure product was not significantly different in relation to placebo at submaximal and maximal exercise. Thus PC seems to have an antiischemiclike effect, probably related to its metabolic activity.

Administration, Oral↗
PubMed1990

Effects of enalapril in normotensive patients with stable effort angina: a double blind, placebo controlled study.

To assess the anti-anginal and anti-ischaemic efficacy of the ACE-inhibitor enalapril in normotensive coronary patients, a double-blind, cross-over, placebo-controlled study was performed. Eight male patients, aged 45-68 years, with stable effort angina were given enalapril (10 mg) once a day or placebo for 7 days. Maximal exercise stress tests 10w/min in the upright position were performed at the end of each period. In comparison to placebo, enalapril increased significantly 1 mm of ST depression time and decreased significantly ST depression at maximal common work. Moreover, enalapril increased significantly the angina threshold and exercise duration. Three of the eight patients ended the exercise without pain. The rate-pressure product was not significantly modified at any time. Thus, the anti-ischaemic and anti-anginal activity may be due to an increase of coronary blood flow, rather than a reduction of MVO2 consumption.

Aged↗
PubMed1990

[Effects of indenolol on left ventricular mass in patients with essential arterial hypertension].

This study evaluated the effect of long-term antihypertensive therapy with indenolol, a beta blocking agent with beta 2 stimulating activity, its antihypertensive hemodynamic mechanism and its effect on hypertensive left ventricular (LV) hypertrophy. Fourteen hypertensive patients, mean age of 48 years, were serially studied during 12- month therapy with indenolol (60-120 mg daily), by recording blood pressure, electrocardiogram and echocardiogram. Blood pressure, heart rate and cardiac output significantly decreased after 1 months of therapy, LV posterior wall thickness decreased after 6 months, interventricular septum thickness and LV mass decreased after 12 months. LV fractional shortening did not change throughout the study. Blood pressure normalized (less than or equal to 140/90 mmHg) in 50% of the patients; LV mass normalized in 40% of the patients. In conclusion, indenolol was an effective antihypertensive agent, also in the long-term treatment. Its antihypertensive hemodynamic effect seems to be due mainly to a reduction in cardiac output. Indenolol caused a regression of LV hypertensive hypertrophy without impairment of LV systolic function.

Adult↗
PubMed1990

Ofloxacin treatment of nongonococcal urethritis. A multi-center study in Asia.

Ofloxacin, a new quinolone antibacterial agent, is active in vitro against gonococcal and nongonococcal urogenital pathogens. Chlamydia trachomatis infection is the most common cause of nongonococcal urethritis. In a multicenter study in seven Asian countries, 105 mal patients with chlamydial urethritis and 46 male patients with nongonococcal and nonchlamydial urethritis were treated with oral ofloxacin at a dosage of 200 mg twice daily for 5 to 10 days. The evaluation performed at day 5 and/or day 10 after treatment revealed good results in 58.2% and 96.8% of the chlamydial urethritis group, and 73.1% and 79.4% of the nongonococcal, nonchlamydial urethritis group, respectively. No severe side effects were observed. Ten-day treatment with ofloxacin showed good clinical efficacy on nongonococcal urethritis.

Asia↗
PubMed1990

[A case of left internal capsular infarction with auditory hallucination and peculiar amnesia and dysgraphia].

A 46-year-old businessman suddenly became to behave curiously on the morning, September 1, 1988. He forgot how to go through an automatic ticket gate, which he used every day. In his company, he also forgot how to open the cash box, and he wrote a meaningless report for his business. From the night on that day, he had experienced auditory hallucination in which whispering words of some criticism to his performance for a few days. On the next day, he was admitted to a psychiatric hospital because he was suggested to have schizophrenia. By day 6 after the onset, his curious symptoms completely disappeared. However, slight verbal memory disturbance and cognitive dysfunction still remained. Because the brain CT on day 6 showed a small localized subcortical infarction in the left hemisphere he was transferred to our clinic on day 20 to elucidate the relation between the abnormal behavior and the infarction. His blood pressure was 116/64 mmHg and pulse was regular 63/min. He was clear and did not have any neurological deficit. He kept his episodic memory regarding the events at the onset and could almost recall them precisely. Results of standard blood tests, electrocardiogram, ultrasound cardiogram, electroencephalogram as well as cerebral angiography were normal. Computed tomography and magnetic resonance imaging showed an infarcted lesion in the genu of the left caudate nucleus, adjacent to the anterior part of the thalamus.(ABSTRACT TRUNCATED AT 250 WORDS)

Agraphia↗
PubMed1989

A cluster analysis for threshold perimetry.

Cluster analysis in perimetry is a technique used in the evaluation of localised visual field loss. It has previously been applied to suprathreshold data and, unlike the indices currently available to indicate localised loss, it is influenced by the relative positions of individual defects. This paper describes a cluster analysis for use with data from Program 31 of the Octopus perimeter. To demonstrate the technique, sensitivity values of normal 60-year-old subject were altered to simulate localised loss. Illustrative examples of clinical cases are given, showing differing degrees of localised loss that do not influence the corrected loss variance (CLV) but influence the computed cluster parameters. It is hoped that the value of this form of analysis will be demonstrated in clinical follow-up of glaucoma patients.

Humans↗
PubMed1989

Myelin-associated glycoprotein (MAG) and rat brain-specific 1B236 protein: mapping of epitopes and demonstration of immunological identity.

The myelin-associated glycoprotein (MAG) and the brain 1B236 protein are 100-kDa glycoproteins containing 30% carbohydrate that exist in two developmentally regulated forms and are specific to the nervous system. Recent cDNA cloning experiments in several laboratories using primarily immunological means of identification have determined the complete primary sequence of a rat brain glycoprotein that seems to correspond to both MAG and 1B236, suggesting that these proteins are identical. However, MAG was previously considered to be an oligodendrocyte/myelin specific component in the CNS at all ages, whereas 1B236 was thought to be primarily a neuronal component in adult rats but synthesized by oligodendrocytes at the time of active myelination. The composite term 1B236/MAG was proposed to describe the molecule identified by the cDNAs. In order to explore further the relationship between MAG and 1B236, as well as their developmentally regulated forms, experiments were carried out on rat samples utilizing synthetic peptides corresponding to sequences throughout the 1B236 molecule, antisera raised to synthetic peptides in the C-terminus of 1B236 that distinguish between the two developmentally regulated forms, and well-characterized polyclonal and monoclonal antibodies raised to purified MAG. Epitope mapping demonstrated that reactive sites were distributed throughout the extracellular and intracellular domains of 1B236/MAG. Only antibodies reacting with the smaller of the two forms of 1B236/MAG detected the glycoprotein in the peripheral nervous system. Both anti-MAG and anti-1B236 antibodies revealed a drastic reduction of the level of 1B236/MAG in 25-day-old myelin-deficient rats and in adult quaking mice, and both types of antibodies revealed a slight shift of 1B236/MAG toward higher apparent Mr in quaking mice as had previously been reported for MAG. The results indicate that MAG and 1B236 are almost certainly identical since they cannot be distinguished immunologically by the reagents available and that quantitatively most of the glycoprotein is associated with oligodendrocytes and myelin rather than neurons at all ages.

Animals↗
PubMed1988

Tissue specificity, localization in brain, and cell-free translation of mRNA encoding the A3 isoform of Na+,K+-ATPase.

The isolation of multiple Na+,K+-ATPase cDNAs from rat brain has led to the discovery of a family of alpha-isoform genes. Using A1 (alpha), A2 (alpha+), and A3 (alpha III) Na+,K+-ATPase gene probes, we have analyzed the distribution of Na+,K+-ATPase mRNAs in adult and fetal rat tissues by RNA blot and hybridization histochemistry. A1 Na+,K+-ATPase mRNA was found ubiquitously among various tissues, with highest levels in transport epithelial and neural tissues. A2 mRNA was found in adult neural and muscle tissues, and A3 mRNA was found only in neural tissues and fetal heart muscle. Both A1 and A2 mRNAs were less abundant in fetal brain than in adult brain; in contrast, A3 mRNA was abundant at both stages. In situ mapping of brain areas that contain A3 mRNA suggests that this Na+,K+-ATPase isoenzyme is expressed predominantly by neural cells. Analysis of Na+,K+-ATPase proteins generated by cell-free translation of synthetic mRNAs suggests that the A3 protein has properties similar to A2 (alpha+).

Animals↗