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Twenty-nine cases of meningioma were studied by immunoperoxidase staining using broad-spectrum antibodies to cytokeratin (AE1/AE3), carcinoembryonic antigen (CEA) and epithelial membrane antigen (EMA). Twenty-six cases (90%) showed positive staining for EMA. All cases were negative for cytokeratin and CEA except for the two cases of secretory meningioma. Normal arachnoidal cells of the leptomeninges from 15 autopsies were studied similarly, and 10 cases (67%) demonstrated positive staining for EMA, but not for CEA and cytokeratin. Literature from previous investigations on epithelial markers of meningiomas is reviewed. It is concluded that meningiomas and normal arachnoidal cells share similar immunohistochemical properties, and that EMA is a useful epithelial marker for meningiomas.

One hundred and sixty-eight cases of tumours of the central nervous system (CNS) from Chinese patients in Hong Kong were reviewed histologically as well as by the immunoperoxidase techniques in equivocal cases. Detailed comparisons were made between this series and previously published series on CNS tumours in Chinese, in other Asians and in Caucasians. The percentage of gliomas was low, and the average age of patients with high grade astrocytomas was low. Meningiomas were relatively common tumours and microcystic meningiomas were a common histological subtype. The percentages of vascular malformations and haemangioblastomas were also higher than those recorded in the West. The difference in incidence in gliomas and vascular malformations between this series and previous reports from mainland China was attributed to a possible difference between southern and northern Chinese.

A rare case of a solitary neurofibroma occurring in a 42-year old female is described. It was attached to the lateral wall of the cavernous sinus. The literature of previously described intracranial nerve sheath tumours not obviously associated with cranial nerves is briefly reviewed.

A 28-year-old woman, 1 month post partum, who presented with headache and gradual onset of total ophthalmoplegia of the left eye, was found at transsphenoidal exploration to have a primary intrasellar germinoma. Craniospinal irradiation resulted in complete resolution of the intracranial tumor. Extensive mediastinal metastasis at 8 months after the operation resulted in a fatal outcome.

Two cases of olfactory neuroblastoma which presented clinically as intracranial lesions are described. Prominent features of epithelial differentiation were present, which led to initial diagnoses of poorly differentiated carcinoma. The true nature of the lesions was only established subsequently by careful histological examination, immunohistochemistry and electron microscopy. The potential towards epithelial differentiation in such tumours was emphasized and certain new histological features were described, including a biphasic epithelial and stromal pattern, papillae formation and positive staining for cytokeratin. These two cases underline the importance of exhaustive examination of poorly differentiated epithelial-like lesions of the frontal lobes by conventional histology, immunohistochemistry and electron microscopy.

Nine cases of microcystic meningiomas, a distinct morphological variant of meningiomas, are reported. They are characterized by a vacuolated and myxomatous histological appearance with multiple cystic spaces lined by stellate-shaped tumour cells. Immunohistochemically, they shared a similar pattern of positive staining for epithelial membrane antigen and vimentin with other meningiomas. Their unusual histological features might lead to problems in differential diagnosis from other intracranial tumours, including schwannomas, chordomas, astrocytomas and angioblastic meningiomas.

Three cases of juvenile chronic myeloid leukemia (JCML) are reported. The patients were aged 3-4.5 years and presented with generalized lymphadenopathy, hepatosplenomegaly, anemia, thrombocytopenia, elevated white blood cell count with monocytosis, and high fetal hemoglobin level. Philadelphia chromosome was absent in two cases studied. The bone marrow showed myeloid hyperplasia with increased monocytoid cells and blasts. Biopsy or postmortem material available in two cases revealed malignant infiltration of lymph nodes, liver, spleen, lungs, intestines, and skin. The neoplastic cells ranged from cells with irregular nuclei possessing nuclear grooves to large blastic cells with round to lobulated nuclei and prominent nucleoli. They showed weak staining for acid phosphatase and nonspecific esterase and exhibited the immunophenotype EBM11+KiM1+KiM6+KiM8+CD4+HLADR+ S-100 protein+. The neoplastic cells of JCML therefore share features of dendritic cells and mononuclear phagocytes. The authors' findings show that JCML is a unique histiocytic malignancy in which S-100 protein is a useful marker.

Sixty-six Chinese patients with rhinitis, with or without asthma, were randomly allocated to a course of injections either with E. pteronyssi-us extract or placebo. The course consisted of 18--22 weekly injections, followed by monthly maintenance injections with the highest concentration for 1 year. Progress was evaluated by a patient's daily diary and monthly assessments by the physician, by comparisons of skin and nasal challenge tests and by the specific serum IgE concentration, before treatment, at the end of the weekly course, and once during the maintenance course. No improvement was detected at the end of the weekly course, but during maintenance there was a consistent benefit to the patients receiving the D. pteronyssinus extract both in the diary and the physician's assessment, especially the former. There was no consistent change in the skin or nasal challenge tests and there was a trivial fall in the serum IgE levels in the patients on the extract. Adverse reactions were much more common in the patients on the extract, but most were trivial. The different methods of assessment used and the role of hyposensitization with D. pteronyssinus are discussed.

The bioavailability of isoniazid, rifampin, and pyrazinamide in 2 combined formulations of the 3 drugs (Rifater) for use primarily in the short-course chemotherapy of tuberculosis has been studied in Chinese patients in Singapore and Hong Kong. One formulation, containing 50 mg isoniazid, 120 mg rifampin, and 300 mg pyrazinamide per tablet is suitable for daily use, whereas the other, containing higher proportions of isoniazid and pyrazinamide, is designed for intermittent treatment, each tablet containing 125 mg isoniazid, 100 mg rifampin, and 375 mg pyrazinamide. Appropriate dosages for the Chinese patients, whose average weight was approximately 50 kg, were 5 and 6 tablets, respectively. Plasma concentrations of the 3 drugs after giving such dosages of the 2 combined formulations were compared in 16 patients, 8 in Singapore and 8 in Hong Kong, by means of a crossover study, with the concentrations obtained when identical doses of the 3 drugs were given using standard separate drug formulations. The concomitant urinary excretions of the drugs and their major metabolites were also estimated. Very similar results were obtained whether the drugs were given as the combined preparations or in their standard separate formulations, demonstrating the excellent bioavailability of all 3 drugs in each of the 2 combined formulations.

The brains of 57 consecutive Chinese patients, aged 65 years or above, dying in a regional general hospital, the causes of death of whom were not primarily intracranial, were examined for parameters of degenerative brain disease--reduction in brain weight, ventricular enlargement, neurofibrillary tangles, senile plaques, granulovacuolar degenerations, and ischemic lesions. Semi-quantitative analysis of these morphological changes suggests that, though generally similar to those observed among Caucasians, they occurred much less frequently, and, as regards senile plaques, in smaller numbers. These observations suggest a lower prevalence of "senile" cerebral alterations in Chinese than in Caucasians.