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Biomedical subjects

J C Chou

Publications and source records attributed to J C Chou.

At least 37 records · Page 2Linked to original sources
PubMed1999

Effects of latanoprost 50 micrograms/ml on Chinese patients with primary open-angle glaucoma and ocular hypertension.

BACKGROUND: This study was designed to determine the efficacy and safety of latanoprost 50 micrograms/ml in Chinese patients with primary open-angle glaucoma (POAG) and ocular hypertension (OH). METHODS: A 14-day randomized, double-masked, parallel-group study comparing topical latanoprost with placebo was followed by a 10-week, one-armed, open-labeled latanoprost treatment study. Intraocular pressure (IOP), visual function, ocular manifestations and miscellaneous adverse effects were evaluated at baseline, and days 1, 7, 14, 15, week 6 and week 12 visits. RESULTS: Twenty-six eligible patients were enrolled in the study. The mean IOP was significantly reduced from baseline only in the latanoprost-treated eyes during the first study period (p = 0.003 on day 1; p = 0.004 on day 7; p < 0.001 on day 14). Meanwhile, the mean IOP was significantly lower in the latanoprost-treated eyes than that in the placebo-treated eyes (p = 0.03 on day 1; p = 0.001 on days 7 and 14). Eyes in both groups showed significantly reduced IOP at each visit of the secondary 10-week latanoprost treatment period, with a mean decrease of 6.12 mmHg. The IOP-lowering effect showed no diminution throughout the study course. Conjunctival hyperemia occurred in 16 of all patients who underwent latanoprost treatment and was the most frequent adverse effect observed. No patient withdrew from the study because of intolerable side-effects. CONCLUSIONS: Topical latanoprost is effective in reducing IOP for patients with POAG and OH. The pressure-lowering effect lasts for at least 24 hours after 1 drop instillation and no drift of effect is noted during this 12-week study. Conjunctival hyperemia was the most common side-effect, which was mild in degree and recovered after discontinuation of the medication.

Adult↗
PubMed1998

Change in plasma prolactin and clinical response to haloperidol in schizophrenia and schizoaffective disorder.

There has been a long-standing interest in plasma prolactin as a potential in vivo indicator of blockade of tuberoinfundibular D2 dopamine receptors. Potential relationships between prolactin response and neuroleptic treatment have been obscured by the use of high doses which have caused prolactin to plateau. With lower doses of neuroleptic now commonly in use, prolactin may be more valuable as a correlate of clinical response. In this study, 23 acutely exacerbated schizophrenic and schizoaffective patients were washed out for at least 6 days and were then treated with haloperidol to achieve fixed low to moderate plasma levels under double-blind conditions. Clinical response, plasma prolactin, and haloperidol plasma levels were measured weekly for 3 weeks. Clinical symptoms at endpoint were related to both prolactin change and final prolactin level during haloperidol treatment. Specifically, fewer symptoms at endpoint were associated with a greater increase in prolactin over time and a higher prolactin level at endpoint. Thus, prolactin increase caused by low to moderate doses of haloperidol may be a correlate of endpoint symptomatology. As lower doses of typical neuroleptics are now in use, prolactin response as a predictor of clinical response may have more clinical utility. Further study of prolactin and clinical response to typical neuroleptics should focus on low neuroleptic doses.

Adult↗
PubMed1998

The gene for indole-3-acetyl-L-aspartic acid hydrolase from Enterobacter agglomerans: molecular cloning, nucleotide sequence, and expression in Escherichia coli.

A 5.5-kb DNA fragment containing the indole-3-acetyl-aspartic acid (IAA-asp) hydrolase gene (iaaspH) was isolated from Enterobacter agglomerans strain GK12 using a hybridization probe based on the N-terminal amino acid sequence of the protein. The DNA sequence of a 2.4-kb region of this fragment was determined and revealed a 1311-nucleotide ORF large enough to encode the 45-kDa IAA-asp hydrolase. A 1.5-kb DNA fragment containing iaaspH was subcloned into the Escherichia coli expression plasmid pTTQ8 to yield plasmid pJCC2. Extracts of IPTG-induced E. coli cultures containing the pJCC2 recombinant plasmid showed IAA-asp hydrolase levels 5 to 10-fold higher than those in E. agglomerans extracts. Homology searches revealed that the IAA-asp hydrolase was similar to a variety of amidohydrolases. In addition, IAA-asp hydrolase showed 70% sequence identity to a putative thermostable carboxypeptidase of E. coli.

Amidohydrolases↗
PubMed1998

Glaucoma following congenital cataract surgery.

BACKGROUND: Glaucoma is a well known complication that arises after congenital cataract surgery. The purpose of this research was to study eyes that manifested glaucoma after congenital cataract surgery and to identify associated factors. METHODS: A retrospective review of patients who received cataract surgery before the age of five was conducted. The chi-squared test for association was used to evaluate risk factors. RESULTS: One hundred and forty eyes of 85 patients were studied. Nineteen eyes of 12 patients had glaucoma, among which 79% was open angle. Patients who underwent secondary membranectomy for visual axis occlusion had a higher risk of glaucoma, especially when secondary membranectomy was performed within one year of primary surgery. Of eight eyes with microcornea, none developed glaucoma after surgery. No significant difference in outcome was found among the surgical methods of cataract removal. CONCLUSIONS: Aggressive clearance of lens cortex during surgery is important. Secondary membranectomy for clearing the visual axis occlusion is associated with post operative glaucoma. Frequent and long-term patient follow-up is mandatory since glaucoma may manifest many years after congenital cataract surgery.

Cataract↗
PubMed1997

Retrobulbar haemodynamic changes studied by colour Doppler imaging in glaucoma.

PURPOSE: To determine the effect of spontaneously elevated intraocular pressure (IOP) on the ocular circulation, and evaluate the result of IOP-lowering procedures in terms of haemodynamics. METHODS: Colour Doppler imaging (CDI) was employed to determine the peak systolic velocity (PSV), end-diastolic velocity (EDV) and time average maximal velocity (TAMV), as well as the Pourcelot ratio (PR) and pulsatility index (PI), of the central retinal artery (CRA), posterior ciliary arteries (PCA) and ophthalmic artery. Various CDI parameters of the eyes with elevated IOP were compared with those of the clinically healthy fellow eyes and the control eyes, separately. Also, data from CDI of glaucoma eyes obtained during the period of elevated IOP and then following IOP-lowering procedures were compared, deliberately avoiding the influence of glaucoma medications. RESULTS: Eyes (n = 12) with elevated IOP showed significantly decreased flow velocities of the CRA and significantly increased PR and PI of the nasal and temporal PCA, compared with the fellow and control eyes, respectively. Following IOP-lowering procedures, the PR and PI of the nasal PCA decreased significantly. CONCLUSION: Spontaneously elevated IOP may induce haemodynamic changes in the CRA and PCA, but no significant change is identified in the ophthalmic artery. Flow velocities tend to decrease while the resistance indices tend to increase with elevated IOP. Such haemodynamic changes may reverse following normalisation of IOP.

Aged↗
PubMed1997

Cornea refractive changes after clear cornea phacoemulsification with foldable intraocular lens.

BACKGROUND: Clear cornea incision for phacoemulsification is the current trend of cataract surgery, with the benefits of small incision, quick rehabilitation and stable wound architecture. In our Oriental eyes with small palpebral fissure the cornea curvature is easily affected by the tight lid compression. Evaluation of the postoperative cornea topographic change after this procedure in our patient is thus necessary. METHODS: Forty eyes with simple cataract were enrolled in this study. Among them 22 were right eyes and 18 were left eyes. All of them were through temporal clear cornea incision. A 2.65 mm length incision for phacoemulsification then enlarged to 3.5 mm for foldable intraocular lens implantation. The wound remained self-healing without suture. Color topographies were taken before and then one and three months after surgery. Palpebral fissures were measured before surgery. RESULTS: Induced cornea astigmatism measured as 0.30 +/- 0.35 diopter in the first postoperative month, and 0.50 +/- 0.43 diopter in the third postoperative month. All the induced astigmatism was toward the incision axis and with the rule shifting. CONCLUSIONS: Tolerable with-the-rule astigmatism shifting around 0.5 diopter was noted postoperatively via temporal clear cornea phacoemulsification with foldable intraocular lens implantation in our patients.

Aged↗
PubMed1997

Combined trabeculectomy and extracapsular cataract extraction with mitomycin C.

BACKGROUND: To evaluate the long-term intraocular pressure (IOP) reduction effect and safety of adjunctive mitomycin C (MMC) (0.02%) in combined trabeculectomy and extracapsular cataract extraction (ECCE) procedure. METHODS: Thirty of forty-one consecutive patients who underwent MMC trabeculectomy and ECCE with a minimum follow-up of 12 months were evaluated. RESULTS: The mean IOP was reduced significantly (p < 0.001) from preoperative 19.2 +/- 3.2 mmHg to postoperative 12.1 +/- 2.7 mmHg, while the mean number of medications decreased from 2.1 to 0.2 at 1-year follow-up. Twenty-seven (90%) patients had IOPs controlled at 15 mmHg or less, and 26 (86.7%) patients required no medication. Net astigmatism and polar value converted from keratometric readings were 1.43 +/- 0.94 diopters and 0.07 +/- 1.38 diopters, respectively, in 1-year follow-up, which were not significantly different from the preoperative values. CONCLUSIONS: Intraocular pressure could be maintained in the low teens without the need for medication in a majority of patients even one year after the combined procedure. No adverse effect on corneal endothelium or limbal wound healing was detected with intraoperative application of 0.02% MMC.

Aged↗
PubMed1996

Neuroleptics in acute mania: a pharmacoepidemiologic study.

OBJECTIVE: To provide an epidemiologic descriptive analysis of the acute drug treatment of inpatients with bipolar mania in state psychiatric facilities in 1990. METHODS: We surveyed the first 3 weeks of drug treatment of all inpatients with bipolar mania who were admitted to 22 New York State adult psychiatric facilities during a 6-month period (n = 528). RESULTS: Almost all patients with mania were treated with neuroleptics. The mean +/- SD neuroleptic dosage was 684 +/- 543 mg/d chlorpromazine equivalents. Sixty-one percent of the patients received lithium and 12% received carbamazepine or valproate. Neuroleptic dosage was related to age, with older patients receiving lower dosages. Patients receiving combination treatment of a neuroleptic with either lithium, an anticonvulsant, or a benzodiazepine received a mean neuroleptic dosage similar to that of patients treated with a neuroleptic alone. CONCLUSIONS: Although their use has been widely discouraged for mood disorders, neuroleptics have been the standard treatment for acute mania.

Adult↗
PubMed1995

Differential involvement of hippocampal G-protein subtypes in the memory process of rats.

Inactivation of Gi and G(o) proteins in the dentate gyrus of the hippocampus by pertussis toxin did not affect memory retention of a one-way passive avoidance learning task in rats. Interference of normal Gs activity in the dentate gyrus by cholera toxin impaired retention performance dose-dependently. Cholera toxin also antagonized the memory-enhancing effect of corticotropin-releasing factor in the hippocampus. However, although Gi and G(o) proteins are probably not involved in the memory consolidation process per se, in animals showing a full retention score there was a significant and long-lasting increase of G(o) concentration in the dentate gyrus. Results of ADP-ribosylation experiments have shown that there was a dose-dependent decrease of ADP-ribosylation in vitro as the concentration of in vivo pertussis toxin and cholera toxin increased. These results together suggest that Gs protein is probably involved in the initiation of the memory consolidation process, while enhanced G(o) expression is the ultimate result upon memory formation. These results provide the first in vivo evidence relating the functions of hippocampal G proteins to the memory process of mammals.

Animals↗
PubMed1994

Heparin-surface-modified intraocular lens implantation in patients with glaucoma, diabetes, or uveitis.

We investigated the clinical outcome in two groups of patients who had an extracapsular cataract extraction and implantation of a heparin-surface-modified intraocular lens (HSM IOL) (Group 1) or a conventional poly(methyl methacrylate) (PMMA) lens (Group 2). Nineteen patients in Group 1 had bilateral cataract extraction with implantation of an HSM IOL in one eye and a conventional lens in the fellow eye. All patients had glaucoma, diabetes, or uveitis. Over the long term, there was no statistically significant difference between groups in visual acuity, corneal edema, anterior chamber reaction, and amount of posterior synechia formation and IOL deposits. Yet short-term clinical evaluation revealed significantly less reaction in eyes with the HSM IOL than in those with the PMMA lens. In patients with both lens types implanted, early postoperative anterior chamber reaction was less and IOL deposits fewer in the eye with the HSM IOL.

Cataract Extraction↗
PubMed1993

Treatment approaches for acute mania.

Drug treatment of mania is conceptually divided into mood stabilizers and tranquilizers. Indications for each are defined and a graphical decision tree for treatment of acute mania is presented. The anticonvulsants carbamazepine and valproic acid have an efficacy comparable to that of lithium and work in many lithium-refractory patients. They have not, however, been sufficiently studied in maintenance treatment. Guidelines are presented for the selection of a mood stabilizing agent as well as for combining two mood stabilizers. Lithium-refractoriness, a key concept in determining drug choice, is poorly defined in the literature and requires refinement. Among tranquilizers, neuroleptics are used most frequently, but their use should be minimized. Neuroleptic dosing of manic patients is probably too high and exposes patients to an unnecessary risk of side effects including tardive dyskinesia. In patients with no history of substance abuse, benzodiazepines can be used instead of neuroleptics or in augmentation of neuroleptics which can then be used at lower doses.

Antipsychotic Agents↗
PubMed1992

Haloperidol blood levels and clinical effects.

This study explored the relationships between plasma levels and the clinical effects of haloperidol in 176 acutely exacerbated schizophrenic or schizoaffective patients. After a single-blind placebo period of 1 week (period 1), they entered the double-blind period 2 randomly assigned to one of three plasma levels of haloperidol: low (2 to 13 ng/mL), medium (13.1 to 24 ng/mL), or high (24.1 to 35 ng/mL). Patients whose conditions did not improve in period 2 continued on one of the three haloperidol levels (period 3). Periods 2 and 3 lasted 6 weeks each. Only minor differences in clinical responses were noted among the three levels of haloperidol. These results imply that low or moderate doses of neuroleptics are appropriate for many acutely psychotic patients.

Acute Disease↗
PubMed1992

Glutamate and other CSF amino acids in Alzheimer's disease.

The authors compared CSF amino acid levels of 10 patients with mild to moderate dementia and probable Alzheimer's disease who had never received antidepressant or neuroleptic medication with those of 10 normal subjects of similar age. The Alzheimer's patients had significantly higher levels of CSF glutamate. This finding was not related to age, sex, or severity of dementia. Elevated CSF glutamate may reflect greater glutamatergic activity early in the course of Alzheimer's disease. The authors speculate that the excitotoxic effects of glutamate may contribute to progressive neuronal loss in Alzheimer's disease.

Age Factors↗
PubMed1991

Recent advances in treatment of acute mania.

Standard and more recent advances in treatment of acute mania are reviewed with special emphasis on controlled studies. Lithium is still the drug of choice and the most common treatment for mania, but some of its limitations have become more apparent, and specific indications for its use are defined. Alternatives to lithium are recommended for psychotic, rapid cycling, severely manic, and lithium-refractory patients. Neuroleptics are effective and used commonly but carry risks of long term side effects. Substantial reduction in neuroleptic dose and duration of exposure is probably feasible in many patients. Neuroleptic-lithium combinations are popular but do not have clear advantages over treatment with a single drug in the initial treatment of acute mania. These combinations have also been associated with increased neurotoxicity. Carbamazepine, both alone and in combination with lithium, has been used increasingly over recent years. Its efficacy is comparable to lithium, but clinical features predicting responsiveness may be different for these two drugs. Carbamazepine-neuroleptic combinations offer little advantage over neuroleptics alone. Valproic acid, verapamil, clonazepam, lorazepam, benzodiazepine-neuroleptic combinations, clonidine, tryptophan, propranolol, and electroconvulsive therapy are also popular, but their effectiveness has not yet been adequately confirmed by controlled studies.

Acute Disease↗
PubMed1987

Dementia in an American-Chinese nursing home population.

Of 58 demented residents in an American-Chinese nursing home, 44 (75.9%) had multi-infarct dementia, seven (12.1%) had possible Alzheimer's disease, four (6.9%) had other dementias, and three 5.2% had unknown disorders. Alzheimer's disease was relatively less prevalent than in U.S. nursing homes overall.

Aged↗