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Biomedical subjects

S K Lin

Publications and source records attributed to S K Lin.

At least 55 records · Page 3Linked to original sources
PubMed1997

Mixed meningococcal and tuberculous meningitis.

Meningococcal meningitis is one of the most common bacterial infections of the meninges worldwide, and tuberculous infection is the most common cause of chronic meningitis in Taiwan. However, mixed meningococcal and tuberculous meningitis is rare. We describe a 27-year-old woman with a case of culture-proven meningococcal and tuberculous meningitis verified by polymerase chain reaction on a cerebrospinal fluid specimen. The patient was initially treated with intravenous antibiotics including penicillin G and chloramphenicol. Though the patient responded well to therapy initially, her subsequent clinical deterioration was finally controlled by long-term antituberculous medications.

Adult↗
PubMed1997

Clozapine dosages and plasma drug concentrations.

Steady-state plasma concentrations of clozapine and its metabolites, desmethylclozapine and clozapine-N-oxide, were measured in 162 Taiwanese patients with refractory schizophrenia. The daily doses of clozapine ranged from 100 to 900 mg, with a mean value of 379.5 +/- 142.2 mg. A dosage of 400 mg/day or lower was used for most patients (n = 131, 81%). Plasma concentrations of clozapine and its two major metabolites were measured using high performance liquid chromatography with ultraviolet detection. The mean plasma clozapine concentration was 566.9 +/- 398.8 ng/mL. The plasma concentrations of desmethylclozapine and clozapine-N-oxide were 46% and 16% of the concentration of the parent drug, respectively. We used an approximate rule that each 100 mg/day dose results in about 150 ng/mL plasma clozapine. This value is about 30% to 50% higher than that reported in Caucasians. The suggested therapeutic plasma clozapine concentration range of 300 to 700 ng/mL can be achieved with a dose range of 200 to 500 mg/day in most Taiwanese patients. Dose-dependent plasma clozapine concentrations were found. The interpatient variation was up to 12-fold in patients receiving the same dose, eg, 400 mg/day (n = 62). In four of these patients, the plasma drug concentrations were very high (1,446 +/- 114 ng/mL). The application of therapeutic drug monitoring in clozapine-treated patients with refractory schizophrenia is important, not only in dose adjustment, prediction of severe side effects such as seizures, and exploration of drug interactions, but also in the effective use of this expensive drug.

Adult↗
PubMed1996

Lack of pharmacokinetic interaction between buspirone and haloperidol in patients with schizophrenia.

The pharmacokinetic interaction between buspirone and haloperidol was evaluated in schizophrenic patients in two different groups. In both groups, haloperidol doses (10-40 mg/day) remained constant for 6 weeks before the addition of buspirone 10 mg three times daily. Serial blood samples were obtained from the 11 patients in group I at baseline (before addition of buspirone) and after administration for 24 hours. The pharmacokinetic parameters of haloperidol were determined alone and with coadministration of buspirone. In group II, buspirone 10 mg three times daily was added to treatment with haloperidol in 27 patients. Blood samples were obtained before addition of buspirone and at weeks 2 and 6 of treatment with buspirone. Samples were obtained 10 to 12 hours after administration of the evening dose and before the morning dose. Haloperidol and its metabolite, reduced haloperidol (RH), were assayed by means of high-performance liquid chromatography with electrochemical detection. Significant changes in the pharmacokinetic parameters of haloperidol were not found in group I; a mean increase in the half-life (t1/2) of haloperidol from 21.5 to 28.1 hours was observed, but this finding was not statistically significant. Under steady-state conditions, plasma levels of haloperidol in the patients in group II did not change significantly from baseline to week 6. Plasma concentrations of RH remained unaltered in both groups. The results indicate that coadministration of buspirone does not markedly affect the pharmacokinetics or plasma concentrations of haloperidol.

Adult↗
PubMed1996

Monitoring of plasma clozapine levels and its metabolites in refractory schizophrenic patients.

Plasma concentrations of clozapine and its metabolites desmethylclozapine and clozapine N-oxide were measured in 61 patients with refractory schizophrenia. Before the initiation of clozapine, each patient was given haloperidol (HL) up to 60 mg/day for at least 4 weeks without improvement. Patients were then given a fixed dose of clozapine 400 mg/day. Patients were assessed with the Brief Psychiatric Rating Scale (BPRS) at baseline before HL therapy, at the end of HL at 6 weeks, before clozapine, and after 6 weeks of clozapine therapy. Clozapine and its metabolites were measured by high-performance liquid chromatography with ultraviolet detection. The mean plasma concentrations of clozapine, desmethylclozapine, and clozapine N-oxide were 598 +/- 314, 281 +/- 140, and 90 +/- 29 ng/ml, respectively. The mean decrease in the total BPRS scores from baseline clozapine to the 6-week treatment period was 11 +/- 4. Clinical improvement was noted to occur in most patients with clozapine plasma levels > 300 ng/ml. Improvement diminished in patients with clozapine plasma levels > 700 ng/ml. The most common adverse effects were sedation and hypersalivation. Significant correlations between plasma clozapine concentrations and adverse side effects were not found.

Adult↗
PubMed1996

Chronic carbon disulfide encephalopathy.

To understand central nervous damage after long-term exposure to carbon disulfide (CS2), 10 patients who had polyneuropathy with various neuropsychiatric symptoms in a viscose rayon plant were studied. Clinical and laboratory examinations including electroencephalography (EEG), brain computed tomography (CT), brain magnetic resonance images (MRI), and carotid duplex sonography were carried out. Clinically, headache, unpleasant dreams, memory impairment, fatigue, anorexia and emotional lability were common in these patients while 2 patients had stroke episodes. EEGs were all normal. Brain CT scan showed mild cortical atrophy in 3 and low density lesions in the basal ganglia in 3. Brain MRI studies also disclosed mild cortical atrophy in 4 and multiple lesions involving the basal ganglia and corona radiata in 4. Carotid duplex sonography revealed mild atherosclerosis with plaques (< 20% stenosis) of extracranial vessels in 6. However there was no significant difference in flow velocities and flow volumes in the extracranial carotid arteries between patients and the normal controls. Interestingly, 2 patients had multiple brain lesions in the subcortical white matter but without strokes. In conclusion, encephalopathy with possible strokes may occur after chronic exposure to CS2, as well as polyneuropathy. The lesions usually involve the basal ganglia and subcortical white matter. Furthermore, MRI study may detect brain lesions particularly in the subcortical white matter areas before the occurrence of stroke.

Brain Diseases↗
PubMed1996

Case report: Pontine haemorrhage following iohexol lumbar myelography.

A case of pontine haemorrhage following lumbar myelography using iohexol is described. Stress, inducing transient hypertension during the procedure, with superimposed neurotoxicity from contrast medium (iohexol) is suggested as a possible mechanism. No brain stem lesion was seen on the initial brain CT scan, possibly because of the high attenuation of the contrast medium in the subarachnoid space. A delayed CT brain scan demonstrated the pontine haemorrhage and was necessary to confirm the diagnosis.

Cerebral Hemorrhage↗
PubMed1996

Disposition of remoxipride in Chinese schizophrenic patients.

The disposition of remoxipride was evaluated in 13 male chronic schizophrenic patients. A single 150 mg dose of remoxipride was administered and blood sampling performed over the following 48 hours. The mean (SD) oral clearance and half-life of remoxipride were 74.46 (25.9) ml/min and 5.46 (0.87) hours, respectively. The mean (SD) AUC for remoxipride was 25,320 (9,820) ng.h/ml. A wide interpatient variability was observed. Compared to Caucasian studies there were no significant differences in the disposition of remoxipride.

Adult↗
PubMed1996

Comparison of calcium phosphate cement mixture and pure calcium hydroxide as direct pulp-capping agents.

Calcium phosphate cement (CPC) and pure calcium hydroxide were used as direct pulp-capping agents on the deliberately exposed pulp tissue of 60 teeth in five monkeys. Their effects on the pulp tissue of individual teeth were observed and histologically compared after 12, 20 and 24 weeks. The results showed that both materials produced similar responses with regard to their biocompatibility and induction of hard tissue barrier formation. Vasodilatation, chronic inflammation and calcification nidi scattered within the pulp tissue of the 12-week group were observed. Twenty weeks after application of capping materials, a crude reparative dentinal bridge with inclusion of soft tissue or bulky capping agents appeared. A more mature, hard tissue barrier with a better degree of mineralization and formation of dentinal tubules was demonstrated in the 24-week group. The above findings associated with the abilities of self-setting and fair compressive strength suggest that CPC appears superior to pure calcium hydroxide and may have potential for clinical application, although many issues remain to be further investigated.

Animals↗
PubMed1995

Intra- and interethnic variability in reduced haloperidol to haloperidol ratios.

Steady-state haloperidol and reduced haloperidol concentrations were measured in 250 schizophrenic patients from 4 ethnic groups: 39 Blacks, 66 Caucasians, 82 Chinese, and 63 Mexican Americans. The distribution of the reduced haloperidol to haloperidol concentration (RH/HL) ratios was bimodal in all ethnic groups, with the antimode determined by probit plot as 0.46, 0.51, 0.36, and 0.76, respectively. With these antimodes, the proportion of patients with low RH/HL ratios were 41%, 42%, 73%, and 57% in the four ethnic groups, respectively. Compared with the other three ethnic groups, in the Chinese patients the ratio was lower. The mean RH/HL ratio in the Chinese was 0.34 compared with 0.81 to 0.87 in the non-Chinese groups. In 53 patients who were treated with two or more haloperidol dosage regimens, steady-state haloperidol and reduced haloperidol drug concentrations obtained from the different regimens were positively correlated with the haloperidol dose (R = .79 and R = .62, respectively). Our data suggest not only the existence of a bimodal distribution in the RH/HL ratio, but also that the antimode separating the low and high ratio subgroups is different among the various ethnic groups.

Adult↗
PubMed1995

A practical single sample dry latex agglutination test for Helicobacter pylori antibody detection.

Assessment of a single serum sample for Helicobacter pylori antibodies is frequently requested in routine diagnostic laboratories. Current enzyme linked immunosorbent assay (ELISA) kits are not ideal for testing small numbers of serum samples and some have low sensitivities, specificities or large grey zones. A panel of 90 serum samples from patients who had presented for routine upper endoscopy was used to compare three kits for the detection of H pylori antibodies: (1) Pyloriset Dry, total antibody latex agglutination, Orion Diagnostica, Espoo, Finland; (2) Pyloriset enzyme immunoassay (EIA), IgG ELISA, Orion; and (3) Hel-p, IgG ELISA, Amrad, Kew, Victoria, Australia. Diagnosis of H pylori positivity was made if culture results and either rapid urease test or histopathology were positive. The sensitivity, specificity, positive, and negative predictive value for each test was as follows: Orion: latex 93.3%, 95.6%, 95.5%, 93.3%, respectively; Orion: EIA-G 84.4%, 97.8%, 97.4%, 84.4%, respectively; and Amrad: EIA-G 100%, 88.9%, 90%, 100%, respectively. The latex test performed better than the EIAs with respect to sensitivity and specificity.

Adult↗
PubMed1995

Helicobacter pylori.

Helicobacter pylori is an important cause of chronic active gastritis and is strongly associated with peptic ulcer disease and gastric cancer. H. pylori colonizes the surface of the gastric epithelium with production of a number of factors, resulting in inflammation and an altered mucosa. H. pylori infection occurs world-wide and the mode of transmission most likely is from human to human via the fecal-oral and/or the oral-oral route. Treatment and, in the future, prevention of this infection may result in a marked diminution of upper gastrointestinal tract disease.

Animals↗
PubMed1995

Determination of human plasma biogenic amines and their metabolites using liquid chromatography with a dual-channel electrochemical detector.

BACKGROUND: Measurement of biogenic amines and their metabolites in plasma has been used for decades to explore the pathophysiology of neuropsychiatric disorders or to examine the mode of action of psychotropic medications. Many advantages of ultrafiltration and high-performance liquid chromatography (HPLC) in assaying human plasma content have been described in our previous study. METHODS: The present HPLC assay, applying a dual-channel electrochemical detector, provides an additional reliable measurement or confirmation of peaks by identifying each peak retention capacity factor and its current ratio in the dual-channel detector. Simultaneous measurements of plasma serotonin, catecholamines and their metabolites by ultrafiltration and microbore HPLC technique is applied to evaluate moclobemide and fluoxetine therapy in patients with major depression. RESULTS: This present HPLC method provides highly specific detection, free from interference by the large offscale peak of plasma ultrafiltrates. Isocratic separation of all analytes by a microbore column is achieved within 15 mins. The detection limit (signal-to-noise ratio = 3) of this method is about 0.2-0.5 pg per injection for all analytes. In addition, the required volume of plasma samples is only 100 microliters. CONCLUSIONS: This rapid, simple and sensitive method for the measurement of human plasma serotonin, catecholamines and their metabolites can be used as a clinical or biomedical research tool. Blood loss is minimal in the present assay, especially in repeated blood sampling for pharmacokinetic studies.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1995

Common carotid artery occlusion: evaluation with duplex sonography.

PURPOSE: To demonstrate the efficacy of carotid duplex ultrasound to diagnose common carotid artery occlusion (CCAO) and to define the clinical features of CCAO. METHODS: We reviewed 5400 carotid duplex ultrasonograms obtained over a 7-year period for suspected carotid artery disease. In cases of CCAO, medical records were reviewed. RESULTS: Thirteen cases (0.24%) of CCAO were diagnosed by carotid duplex ultrasonography, including five cases of isolated CCAO. Seven cases were proved by cerebral angiography. Cerebral angiography failed to demonstrate patent internal carotid arteries in two cases of isolated CCAO. Mean age of onset was 67 +/- 9 years. The main clinical presentation was stroke in nine cases (69%). The most common vascular risk factors were hypertension (62%) and heart diseases (54%). Three patients had a history of radiation therapy to the neck. Two of five patients with isolated CCAO had major stroke, with good recovery in one, whereas five of eight patients with CCAO had major stroke; among them, only one had good recovery. CONCLUSION: Patients with isolated CCAO may have a better outcome than patients with CCAO. Duplex sonography, particularly with color-coded flow imaging, provides an accurate examination to define the patency of the arteries distal to the carotid bifurcation. The clinical features of CCAO are similar to those of internal carotid artery occlusion except for the low prevalence of CCAO.

Aged↗
PubMed1995

Transcranial color-coded sonography in normal Chinese adults and its clinical applications.

We have performed transcranial color-coded sonography to 150 normal adults. Through the temporal, orbital and foraminal windows, by using a 2 MHz pulsed-wave transducer, we were able to directly insonate the brain parenchyma, and to obtain color-coded Doppler vascular imagings and flow velocities of the intracranial basal cerebral arteries. There was no significant difference of blood flow velocities and resistance index between the right and left hemispheres. The mean velocities was highest in the middle cerebral artery and lowest in the ophthalmic artery while which had the highest resistance index. Female had higher mean velocity in basilar artery. The mean velocity, peak systolic velocity, as well as end diastolic velocity decreased significantly with age in middle cerebral artery, anterior cerebral artery and basilar artery. Four illustrative cases with abnormal findings were presented to compare with normal control. Some pitfalls in ultrasonography were also described.

Adolescent↗
PubMed1995

Secondary dentin deposition in dens evaginatus: report of a case.

An unusual case of dens evaginatus in a 22-year-old man is reported. The involved tooth was the right upper second premolar which appeared to have been segregated into coronal and apical segments during the disease process. Although abscess formation was noted in the coronal portion, continuing secondary dentin deposition was found over the displaced apical segment. The pathogenesis of this unusual dentinal bridge formation is proposed based on the microscopic and radiographic findings.

Adult↗
PubMed1995

High prevalence of Helicobacter pylori antibodies in an institutionalized population: evidence for person-to-person transmission.

OBJECTIVE: To evaluate the prevalence of H. pylori antibodies in mentally and physically handicapped adults living together in a long-term care facility. METHODS: One hundred twenty-two institutionalized subjects from six living areas were compared to a normal representative Caucasian population obtained by random sampling from the urban population area of Melbourne. Serum samples from 1977 and 1989 from 122 subjects were tested for H. pylori antibody by an ELISA technique. The data were analyzed by Student's t test, chi 2 test and logistic regression. RESULTS: Ninety-two of the 122 subjects (75%) from whom sera was collected in 1989 were seropositive for H. pylori, compared with only 23% in age- and sex-matched control subjects (p < 0.0001). The prevalence of H. pylori antibodies in 1977 was 34% (42/122). Of the remaining 80 seronegative subjects, 51 (61.4%) converted to became positive in the 12-yr interval. The annual seroconversion rate was 7.4%, with an average of 4.25 newly positive subjects each year. The prevalence of H. pylori in 1989 was significantly higher than in 1977 after adjustment for age (odds ratio 2.39, 95% CI 1.1-5.3, p = 0.03). CONCLUSIONS: H. pylori antibodies are significantly more prevalent in institutionalized adults compared with controls from the general population. These data support the hypothesis that H. pylori is acquired by either fecal-oral or oral-oral transmission.

Adult↗
PubMed1995

Helicobacter pylori in ulcerogenesis.

Patients with peptic ulcer disease have elevated gastric acid secretion, hyperfunction of G cell, impaired bicarbonate secretion, increased levels of pepsinogen I and the presence of inflammatory mediators as well as Helicobacter pylori-induced gastroduodenitis and gastric metaplasia in the duodenum (in duodenal ulcer patients). Non-H. pylori-associated ulcers include those due to non-steroidal anti-inflammatory drugs, Zollinger-Ellison syndrome, and those related to other forms of gastritis. Evidence of H. pylori in ulcerogenesis includes the higher prevalence of H. pylori in gastritis and peptic ulcer patients plus the important observation that H. pylori eradication results in healing and long-term cure of ulcer disease. The precise mechanism of mucosal injury and ulceration is unclear. Bacterial and inflammatory factors are involved as well as host changes in hormones and gastric acid secretion.

Anti-Bacterial Agents↗