Biomedical subjects
Publications and source records attributed to J Chan.
The first known case of a primary pure ovarian carcinoid in pregnancy occurred. Urinary 5-hydroxyindol acetic acid (5-HIAA) assays were negative despite elevated whole blood serotonin levels. Careful surgical staging and serial determinations of 5-HIAA and serotonin are recommended for detecting evidence of recurrent or metastatic disease.
Nasopharyngeal carcinoma usually presents with enlargement of upper cervical lymph nodes, epistaxis, postnasal discharge, aural symptoms or cranial nerve palsy. Parotid swelling as the first and presenting symptom creates a diagnostic problem to both clinicians and pathologists. The authors report here two such cases to draw attention to this diagnostic problem and discuss the therapeutic implications.
Fifty-four cases of ectopically erupted maxillary permanent first molars were studied with a method using the measurements obtained from photographs of the study casts. The amount of relative loss of anteroposterior arch length of the right and left sides was shown to correlate with the increased mesial angulation of the maxillary permanent first molar. The bilateral ectopic group has a significantly larger mesial angulation of the permanent first molar on a maxilla with shorter anteroposterior arch length. The relative loss of arch length with ectopic eruption of the permanent first molar limits the use of unilateral appliances for treatment. The use of an appliance with bilateral arch support seems preferable.
Two Chinese patients with sinus histiocytosis and massive lymphadenopathy are reported. The results of enzyme and immunohistochemical studies are presented.
A subpopulation of human synovial cells develop a stellate morphology during in vitro culture. These cells, called stellate cells or dendritic cells, appear capable of collagenase production. In other tissues, particularly mouse spleen and human peripheral blood, cells with a similar shape express immune region associated (Ia) antigens, stimulate a primary mixed leukocyte reaction, and present antigen to lymphocytes. To characterize synovial dendritic cells, we observed changes in their morphology by time-lapse videomicroscopy. Parallel cultures of cells from the same specimens were observed periodically for HLA-DR surface antigens by immunofluorescence microscopy. During culture, synovial dendritic cells gradually lost their distinct morphologic appearance and became indistinguishable from fibroblasts. Moreover, fibroblasts occasionally assumed a dendritic morphology. When cells were examined at 24-48 h or later, we could not detect HLA-DR antigens on synovial dendritic cells, defined as cells with 4 or more stellate, branching projections. Cells with only 1-3 projections often had HLA-DR antigens. Because human synovial dendritic cells may lose their characteristic morphology upon culture and because they appear to lack Ia antigens in the unstimulated state, we suggest that synovial dendritic cells may be closely related to fibroblasts.
Human urine contains a specific inhibitor of interleukin 1 (IL 1) that is found in increased amounts during fever. This inhibitor was purified by using a sequence of ammonium sulfate fractionation, DEAE cellulose ion-exchange chromatography, molecular sieve chromatography on Sephacryl S-200, affinity chromatography on concanavalin A (Con A) Sepharose, and polyacrylamide gel electrophoresis. Two peaks of IL 1 inhibitory material were eluted from the polyacrylamide gels. One peak contained three proteins of 29, 32, and 67 kd, respectively, which could be visualized by silver staining. The second peak contained only a small amount of the 67 kd protein. A partially purified inhibitor fraction was found to cross-react with antisera directed against two low m.w. urine trypsin inhibitors that are cleavage products of the serum inter-alpha-trypsin inhibitor. Although these findings suggest that the urine IL 1 inhibitor may be related to the inter-alpha-trypsin inhibitor, a more exact identification will require either a homogeneous inhibitor preparation or a monospecific antiserum.
The ultrastructural morphology of serotoninergic terminals and their synaptic relation with catecholaminergic neurons were examined in the medial nuclei of the solitary tracts (m-NTS) using combined autoradiographic and immunocytochemical methods. Adult rats were pretreated with a monoamine oxidase inhibitor and subjected to a 2-hour intraventricular infusion of 50 nM tritiated 5-hydroxytryptamine (3H-5HT). At the termination of the infusion, the brains were fixed by aortic arch perfusion with a mixture of 4% paraformaldehyde and 0.5% glutaraldehyde. Coronal Vibratome sections through the NTS and more rostral raphe nuclei were immunocytochemically labeled with specific antiserum to serotonin or tyrosine hydroxylase and then processed for autoradiography. By light microscopy, concentrations of reduced silver grains indicating uptake of 3H-5HT usually paralleled the localization of peroxidase immunoreactivity for serotonin in neuronal perikarya of the rostral raphe nuclei and in varicosities in the brainstem. The 3H-5HT-containing varicosities were found throughout the medial and commissural portions of the NTS, where they were frequently associated with processes showing immunoreactivity for the catecholamine-synthesizing enzyme tyrosine hydroxylase. Ultrastructural examination of the m-NTS revealed that the silver grains for 3H-5HT were accumulated over axon terminals. The 5HT-labeled terminals contained a heterogeneous population of vesicles and formed both symmetric and asymmetric synapses with dendrites. The recipient dendrites were either, unlabeled or showed immunoreactivity for tyrosine hydroxylase. These findings support a direct serotoninergic modulation of catecholaminergic neurons within the rat m-NTS.
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The chemiluminescence of fluorescein derivatives is greatly enhanced when they are conjugated to proteins. We exploited this property in devising a chemiluminescence immunoassay for rubella antibodies. In this sequential "sandwich"-type assay, tubes coated with rubella antigen are used for antibody separation and goat antibody to human IgG conjugated with fluorescein isothiocyanate is used for detection of bound rubella antibodies.
The accumulation of transported materials in cut axons is demonstrated by the light and electron microscopic immunocytochemical localization of substance P and enkephalin in the caudal medulla and cervical spinal cord of adult rat. Two days following unilateral knife-cuts in the caudal medulla or spinal (C2-C3) levels, substance P and enkephalin-like immunoreactivity (SPLI and ELI) are detected in lesioned axons located rostral and caudal to the transection. Rostrally, SPLI and ELI are detected in the lateral reticular region and ventrolateral fasciculus corresponding to the location of previously identified bulbospinal pathways. Caudally, previously unidentified, propriospinal pathways showing SPLI are detected in the dorsal columns and in the dorsolateral fasciculus. In contrast, ELI is found caudal to the transection only in the reticular region of the medulla. For both peptides, immunoreactivity is present throughout axons containing numerous large, dense core, and small clear vesicles. These results support the concept of both particulate and soluble modes of transport for substance P and enkephalin within axons of the central nervous system.
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A technique for dual staining of cells using terminal deoxynucleotidyl transferase (TdT) and myeloperoxidase (MPO) is described. The technique has been applied to cells of two patients. One patient had chronic myelomonocytic leukemia evolving into acute myelomonocytic leukemia. The other patient had chronic myelogenous leukemia in blast crisis. Our findings indicate that TdT and MPO are exclusive markers except for a rare precursor cell with dual staining in one patient. This study supports the concept of acute mixed leukemia.
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Viscometric assays were used to demonstrate the activity of thermolysin (EC 3.4.24.4) on native type III collagen in solution. Analysis of the reaction products by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and electron microscopic visualisation of segment long spacing aggregates demonstrated localised cleavage of the collagen in the collagenase susceptible region.
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