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Biomedical subjects

C C Mao

Publications and source records attributed to C C Mao.

At least 19 recordsLinked to original sources

Adenosquamous cell carcinoma of the cervix--a clinical analysis of 23 cases.

From January 1976 through December 1985, 895 patients with cervical carcinoma were treated with radical hysterectomy and pelvic lymphadenectomy. The surgical specimens of 23 cases were proved to be adenosquamous cell carcinoma, the incidence being 2.6%. Among them, 15 were at stage IB, 7 were at stage IIA and one was at stage IIB. The overall 5-year survival rate was 55.0% and there was no difference between patients at stage IB and IIA. During the same period the 5-year survival rate of squamous cell carcinoma was 87.5% for patients at stage IB and 75.0% for patients at stage IIA. Pelvic lymph node metastasis and parametrial involvement are considered to be poor prognostic factors. When metastasis or invasion happens, the metastatic or invasive lesions can be found in the form of pure squamous carcinoma or adenocarcinoma. Postoperative adjuvant radiotherapy (external irradiation plus brachytherapy) seems to be effective in preventing recurrence. Chemotherapy (PVB regimen) needs more clinical evaluation. In this study, when metastasis or recurrence developed, the response to radiotherapy and/or chemotherapy were poor and 75% of patients died within one year.

Adenocarcinoma

Vaginal intraepithelial neoplasia: diagnosis and management.

A review of 42 patients with vaginal intraepithelial neoplasia (VAIN) seen in Gynecologic Department of Veterans General Hospital-Taipei between 1971 and 1987 was made. The patients were from 36 to 79 years of age with a mean 58 of years. Fifteen patients (36%) had synchronous cervical neoplasia, 26 cases (62%) had antecedent cervical neoplasia and one had undergone operation for uterine myoma. Twenty-four of 27 patients with VAIN alone presented an abnormal Papanicolou smear. The upper one third of the vagina was the most common site of the lesion. Multifocal lesions were demonstrated in 58% cases while unifocal disease accounted for 42% cases who had VAIN subsequent to cervical neoplasia. Colposcopically directed biopsies were used for diagnosis in 13 patients. White epithelium and punctation were the most common findings of VAIN. While the results of different treatments were reviewed, surgical excision was found to be the most frequently employed method and radiotherapy was the second. Both were effective and 5 patients died of vaginal disease. On account of the relatively benign nature of VAIN than that of invasive vaginal cancer and the need for preservation of a functional vagina, more conservative approaches, for example, topical 5-Fluorouracil application and carbon dioxide laser vaporization, are discussed.

Adult

Anterior operculum syndrome.

The anterior operculum syndrome (AOS) is a well-defined clinical entity that has received little attention in the English literature. We report the clinical and CT findings in 3 cases of AOS; 2 were caused by bilateral cerebral infarctions secondary to bilateral internal carotid occlusion and 1 by the residual effects of viral encephalitis. Although there was variability in the range of deficits found in our cases, each of these patients presented with characteristic facio-pharyngo-glosso-masticatory diplegia with a dramatic automatic-voluntary movement dissociation. This syndrome deserves attention for its characteristic anatomic and prognostic implications.

Adult

Movement disorders in multiple sclerosis.

Movement disorders other than cerebellar tremor are rare clinical manifestations of multiple sclerosis (MS). Two cases of parkinsonism and a case of chorea associated with MS are reported, and the literature is reviewed.

Adult

The turnover rate of gamma-aminobutyric acid in the nuclei of telencephalon: implications in the pharmacology of antipsychotics and of a minor tranquilizer.

The turnover rate of GABA is measured in substantia nigra, globus pallidus, N. accumbens, and striatum of rats injected with muscimol, a potent GABA agonist, and diazepam. The similarity of action of the two drugs on GABA turnover further supports the theory that diazepam acts as a GABA-mimetic drug. Haloperidol and clozapine affect GABA turnover differently in different nuclei. Haloperidol decreases GABA turnover in caudate but does not affect that in substantia nigra, whereas clozapine increases GABA turnover in both areas. However, both drugs accelerate GABA turnover in globus pallidus and N. accumbens. It is suggested that an increase of GABA turnover and perhaps of GABA release in striatum and substantia nigra may account for the lack of tardive dyskinesia and extrapyramidal side effects of clozapine.

Aminobutyrates

Application of principles of steady-state kinetics to the estimation of gamma-aminobutyric acid turnover rate in nuclei of rat brain.

13C-labeled glucose (50 mumol/kg/min) was infused into the rat tail vein for 10 minutes. The animals were killed by a microwave beam focused to the skull at various times after the infusion. In brain nuclei the concentrations of glutamate and gamma-aminobutyric acid (GABA) and their enrichment in 13C were measured by mass fragmentography. The results showed that in the five brain areas studied, substantia nigra contained the highest GABA concentration, followed by globus pallidus, N. accumbens, deep cerebellar nuclei, N. caudatus and cerebellar cortex. The concentrations of glutamate and GABA were comparable in some nuclei (substantia nigra and globus pallidus), but not in others. The glutamate content was 3 to 6 times greater than GABA content in cerebellum (cortex and nuclei) N. accumbens and N. caudatus. The turnover rates of GABA in substantia nigra, globus pallidus, N. caudatus and N. accumbens were calculated by applying principles of steady-state kinetics to the changes with time in the 13C enrichment of glutamic acid and GABA. In substantia nigra, N. accumbens and N. caudatus, the percentage of 13C incorporation into glutamic acid and GABA reached its maximum 10 to 15 minutes after the infusion. In N. caudatus and N. accumbens, the percentage of 13C incorporation into GABA was higher than that in substantia nigra and globus pallidus. The turnover rates of GABA were very similar in N. caudatus, N. accumbens, substantia nigra and globus pallidus (385-562 nmol/mg of protein per hr), but the turnover times were much faster in N. caudatus and N. accumbens. It must be kept in mind that in N. caudatus and N. accumbens the glutamate pool was several-fold greater than that of GABA. Since the data obtained indicate that the compartmentation is more complicated than in the model assumed for turnover estimations, this method should be used only for comparative purposes in drug studies. The validity of this method to obtain absolute measurements of GABA turnover remains to be documented.

Aminobutyrates

Evidence for an involvement of GABA in the mediation of the cerebellar cGMP decrease and the anticonvulsant action diazepam.

Subcutaneous injections of isoniazid or picrotoxin increase the cerebellar content of 3',5'-cyclic guanosine monophosphate (cGMP) without changing the 3',5'-cyclic adenosine monophosphate cAMP. This increase was dose dependent and the threshold for the cGMP increase was lower than that for convulsions. In cerebellum the increase of cGMP content elicited by isoniazid but not that caused by picrotoxin was paralleled by a decrease of GABA content. Diazepam doses starting from 1.74 mumol/kg intraperitoneally produced a dose dependent decrease of cerebellar cGMP concentration without changing cAMP or GABA content. Smaller doses of diazepam (0.5 mumol/kg i.p.)failed to decrease the basal cerebellar content of cGMP. However, this dose of diazepam antagonized the increase of cGMP produced by isoniazid but not that produced by picrotoxin. Higher doses of diazepam were necessary to block the increase of cerebellar cGMP elicited by picrotoxin. Low doses of diazepam (0.14 mumol/kg) antagonized the convulsions in 50% of the rats injected with 3.3 mmol/kg of isoniazid. The doses of diazepam required to block picrotoxin, pentylenetetrazol or strychnine convulsions were 7, 25 and 40 times higher than those required to block isoniazid convulsions, respectively. Desmethyldiazepam, chloridiazepoxide, oxazepam were also several times more potent in antagonizing isoniazid than picrotoxin, pentylenetetrazol, or strychnine convulsions. In contrast, barbiturates were equipotent against all the convulsants studied. These experiments suggest that diazepam may act in the CNS either by altering the disposition of endogenous GABA or by mimicking the action of GABA at specific synaptic receptors.

Aminobutyrates