Biomedical subjects

K L Ho

Publications and source records attributed to K L Ho.

At least 55 records · Page 3Linked to original sources

PubMed1990

Gliosarcoma: a histologic and immunohistochemical reaffirmation.

Seven cases of mixed glioblastoma multiforme (GBM) and sarcoma, or gliosarcoma (GS) and six cases of GBM with a prominent pilocytic or spindle cell component were studied with a panel of ten antibodies using the ABC method. All 13 cases were originally diagnosed as GS based on hematoxylin and eosin- (H&E) and reticulin-stained sections. In all GS, the glial component stained strongly for glial fibrillary acidic protein (GFAP), and most stained for S-100 protein, while the sarcomatous areas of GS did not stain for either of these antigens. This resulted in a characteristic, bimorphic marmorate staining pattern. In contrast, spindled GBM stained diffusely for GFAP and S-100 protein. Vimentin was detected in neoplastic glia of both GBM and GS and in the sarcomatous foci of GS. A spectrum of cytokeratins, Factor VIII, desmin and neurofilament were not detected in either GS or GBM. Actin, Leu 7 and alpha-1-antichymotrypsin were focally and inconsistently found in both GS and GBM. Perithelial spindle cell proliferations and intramural spindle cells within thick-walled vessels stained for GFAP, S-100 protein and/or vimentin. These studies confirm that GS is a true biphasic neoplasm that frequently cannot be distinguished from pilocytic or spindled GBM on routine histologic examination. Invasion of the dura, leptomeninges, and hyperplastic or hypertrophied blood vessels by malignant glial cells particularly confounds interpretation of H&E and reticulin stains. Immunohistochemical staining for GFAP complements the reticulin stain in confirming the presence of two cell populations in GS.

Adult↗

PubMed1990

Modification of exercise-aggravated coxsackievirus B3 murine myocarditis by T lymphocyte suppression in an inbred model.

The effects of T lymphocyte suppression on coxsackievirus B3 (CB3) myocarditis and its augmentation by exercise were determined in this study. Three-week-old male C3H/HeN mice were divided into four groups. Group 1 mice were infected intraperitoneally (IP) on day 0 with CB3 10(2.5) TCID50, were made to swim daily from days 1 to 9, and were immunosuppressed with daily doses of cyclosporine A (25 mg/kg IP) from days -2 to 8, plus 0.1 ml antithymocyte 1.2 IgG 2a monoclonal antibody IP on day 0. Mice in group 2 were infected and made to swim daily from days 1 to 9. Mice in group 3 were infected and immunosuppressed as outlined. Mice in group 4 were infected IP with CB3. Mortality rates during the acute phase of infection (days 1 to 9) were as follows: group 1, 4% (1/25); group 2, 52% (13/25); groups 3 and 4, 0. Overall mortality rates through day 21 were as follows: group 1, 67% (17/25); group 2, 72% (18/25); group 3, 40% (10/25); and group 4, 4% (1/25). Mean viral titers in serum were highest in the immunosuppressed groups throughout the study. Myocardial viral titers (mean log10 TCID50) were higher in group 2 mice than in group 1 on days 6 (10(6.9) vs 10(4.6)) and 9 (10(8.4) vs 10(7)); however, these titers peaked in group 1 mice on day 13 (10(9.7)). Myocardial inflammation, necrosis, and mean heart weight/body weight ratios were lower in group 1 compared with group 2 on days 6 and 9 but were maximal on day 13 in group 1. Neutralizing antibody titers were lower in immunosuppressed mice on days 6 and 9; however, a rebound increase occurred on day 13.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Microtubular aggregates within rough endoplasmic reticulum in myxopapillary ependymoma of the filum terminale.

Aggregates of microtubules with-in rough endoplasmic reticulum were found in many neoplastic cells of three cases of myxopapillary ependymoma of the filum terminale studied ultrastructurally. The cytoplasm and cellular processes of some neoplastic cells were distended by the aggregates. In general the involved rough endoplasmic reticulum contained three to six microtubules, but some enclosed more than 10 microtubules. The enclosed microtubules were straight parallel hollow cylindrical structures with fuzzy coats. They had an inner diameter of 12 to 15 nm, an outer diameter of 30 to 35 nm, and a center-to-center distance of 50 to 62 nm. The involved rough endoplasmic reticulum often showed various degrees of loss of surface ribosomes and some appeared totally degranulated. Vacuolar degeneration of involved rough endoplasmic reticulum with fragmentation and disintegration of the enclosed microtubules was frequent. Direct relationship of the enclosed microtubules to the cytoplasmic microtubules and ciliary formation was not found. This unusual microtubular aggregate has not been described in other types of ependymoma, or in other brain tumors. They may represent a characteristic ultrastructural feature of myxopapillary ependymoma.

Adult↗

PubMed1989

Localization of immunoreactive thymosin alpha 1 in astrocytes of normal human brain.

We employed an immunocytochemical method to examine human brain for the presence of immunoreactive thymosin alpha 1 (T alpha 1), a peptide derivative of thymic tissue, using a well-characterized antiserum. For cell identification, serial sections were stained with antisera to thymosin beta 4(T beta 4), another thymic peptide that identifies oligodendrocytes, and with anti-glial fibrillary acidic protein (GFAP) antiserum that stains astrocytes in a double-staining technique using avidin-biotinylated horseradish peroxidase or avidin-biotinylated alkaline phosphatase complex. Antiserum to T alpha 1 stained the cell body, but not the processes, of GFAP-positive astrocytes, suggesting that T alpha 1 is a common antigen shared between thymus and astrocytes. Because T alpha 1 and its precursor molecule play a role in cell proliferation and immunomodulation, our findings could explain the role of astrocytes in certain central nervous system diseases.

Adult↗

PubMed1989

Intraspinal bronchogenic cyst: ultrastructural study of the lining epithelium.

This report describes the ultrastructural characters of the lining epithelium of a symptomatic intraspinal bronchogenic cyst at the C5-T2 level of a 21-year-old female. Six distinct cell types were recognized: ciliated cells, non-ciliated cells, and goblet cells that reached the lumen, and basal cells, Kulchitsky cells and undifferentiated cells that were basally located and did not reach the lumen. The microvilli of non-ciliated cells were coated with granulofibrillary material. Discharge of granular contents from goblet cells was noted. Abnormal cilia, particularly compound cilia, were frequent. Complex interdigitations of cytoplasmic membrane with prominent desmosomes were present in the pseudostratified region. Kulchitsky cells contained characteristic membrane-bound dense-core neurosecretory granules. Intraepithelial unmyelinated axons were observed but none were closely associated with Kulchitsky cells. The types of cells forming the lining epithelium of the present cyst and their topographic distribution within the epithelium are very similar to those of the normal tracheobronchial epithelium.

Adult↗

PubMed1989

Subarachnoid epithelial cyst of the cerebellum. Immunohistochemical and ultrastructural studies.

This report describes the immunohistochemical and ultrastructural studies of a subarachnoid epithelial cyst of the cerebellum found incidentally at autopsy of a 76-year-old man. The cyst was composed of an inner epithelial layer, a middle connective tissue layer and an outer arachnoid membrane. The epithelial layer was strongly positive for cytokeratin, carcinoembryonic antigen and epithelial membrane antigen, but negative for glial fibrillary acidic protein, S-100 protein, neuron-specific enolase and vimentin. Ultrastructurally, the epithelial layer had four distinct types of cells: ciliated cells, non-ciliated cells with coated microvilli, basal cells with tonofilaments and desmosomes, and cells with dense-core secretory granules (Kulchitsky cells). The latter two types of cells have not been described previously in epithelial cysts of the CNS. The lining epithelium closely resembled the upper respiratory epithelium. The findings suggest that the cyst was of endodermal rather than neuroectodermal origin.

Aged↗

PubMed1989

Zhi-mu saponin inhibits alpha-fetoprotein gene expression in developing rat liver.

1. A saponin isolated from the Chinese herb zhi-mu (Anemarrhena asphodeloides Bunge) modifies alpha-fetoprotein production when injected into newborn rats. 2. The serum level of AFP was determined quantitatively by immunorocket electrophoresis. 3. AFP serum levels were reduced to 60% of the control by zhi-mu saponin (ZMS). 4. The lower AFP level in drug treated rat serum is not due to a change in the pattern of serum AFP variants. 5. AFP mRNA levels in ZMS-treated rat livers, measured by RNA dot hybridization, decreased to about 50% of control levels after 4 days treatment. 6. Results from tritium labeled dexamethasone competition assays suggest that ZMS may act on AFP gene expression through glucocorticoid receptor mediated action.

Animals↗

PubMed1989

Basophilic bodies of skeletal muscle in hypothyroidism: enzyme histochemical and ultrastructural studies.

Basophilic bodies of skeletal muscles from two patients with hypothyroidism were examined by enzyme histochemistry and ultrastructural study of ultrathin sections stained with periodic-acid-thiocarbohydrazide-silver proteinate for polysaccharides. Some additional characterizations of basophilic bodies were observed: basophilic bodies were found exclusively in type 1 fiber; basophilic bodies were devoid of myofibrillary adenosine triphosphatase, oxidative enzymes, and phosphorylase; and both fibrillary and granular components of basophilic bodies stained strongly for polysaccharides. The polysaccharide nature of basophilic bodies is in keeping with the previous suggestion that the formation of basophilic bodies in hypothyroid patients is related to an impairment of carbohydrate metabolism. Their selective involvement of type 1 fiber and preferential occurrence at the myotendinous junction remain obscure.

Adenosine Triphosphatases↗

PubMed1989

Transient hyperthermia protects against subsequent forebrain ischemic cell damage in the rat.

We heated Wistar rats (n = 10) to 41.5 +/- 0.2 degrees C for 15 minutes, 24 hours before the induction of forebrain cerebral ischemia. We subjected 23 rats to forebrain ischemia without prior heating. Ischemic cell damage in the medial, lateral, and overall CA 1/2 hippocampus, inferior frontal cortex, and dorsal-lateral striatum was significantly (p less than 0.05) less severe in heated animals than in nonheated animals.

Animals↗

PubMed1989

Morphogenesis of Michaelis-Gutmann bodies in cerebral malacoplakia. An ultrastructural study.

Malacoplakia was found in the brain biopsy specimen from the wall of a cystic lesion in a 4-month-old girl. Ultrastructural study of the Michaelis-Gutmann bodies revealed that the initial stage of calcification appeared to be the deposit of needle-shaped apatite crystals within intracytoplasmic membrane-bound vesicles of histiocytes. Accumulation of apatite crystals and coalescense of calcified vesicles resulted in the formation of large laminated calcospherules. Extracellular Michaelis-Gutmann bodies and apatite crystal-containing matrix vesicles were also noted. Calcified vesicles and the Michaelis-Gutmann bodies were not observed in the phagolysosomes. Bacteria and viral particles were not identified. These findings suggest that matrix and intracytoplasmic membrane-bound vesicles play an important role in the initial stage of the formation of Michaelis-Gutmann bodies and that a mechanism other than bacterial or viral infection may be involved in cerebral malacoplakia.

Apatites↗

PubMed1987

Ultrastructure of cerebellar capillary hemangioblastoma. VI. Concentric lamellar bodies of endoplasmic reticulum in stromal cells.

Concentric lamellar bodies of endoplasmic reticulum (CLB) were found in the stromal cells of all five cases of cerebellar capillary hemangioblastoma studied ultrastructurally. CLB were often present in the stromal cells with voluminous loose cytoplasm, particularly those close to the capillaries. They were rarely seen in small stromal cells with abundant organelles and stromal cells distended by large lipid droplets. Small lipid droplets were usually present in the center or in the vicinity of CLB. Vesiculation and vacuolization of the lamellar arrays of CLB were common. Some vacuolized CLB were transformed into large, varying-shaped, multilocular bodies. Some stromal cells were markedly distended by numerous large vacuoles derived from CLB. Granulo-fibrillary material was frequently present in the vacuolized lamellae. Discharge of vacuoles into the interstitial space was observed. It is suggested that CLB is one of the characteristic ultrastructural features of the stromal cells. They may represent a special type of hyperplasia of the endoplasmic reticulum, but their functional significance is not known.

Adolescent↗

PubMed1987

A glioependymal cyst of the cerebellopontine angle. Immunohistochemical and ultrastructural studies.

Epithelial cysts in the subarachnoid space are infrequently reported and appear to be histogenetically heterogenous. This report describes the gross, immunohistochemical and ultrastructural findings of an asymptomatic isolated 3-cm epithelial cyst in the cerebellopontine angle. The cyst wall was composed of an inner glial layer with a luminal ependymal lining and an outer fibrous layer with no external lining cells. The lining ependymal cells had vacuoles, bleb-like protrusions, normal and abnormal cilia, and microvilli, the later were sometimes distended and detached into the lumen. They possessed neither pinocytic vesicles nor a basement membrane. The glial layer contained astrocytes, glial bundles and ependymal cells, often in pairs and forming intercellular lumina with cilia and microvilli. Some single and paired ependymal cells contained abnormal cilia and intracytoplasmic lumina. The blood vessels within the glial layer had elongated tight junctions and were fenestrated. The glial layer was demarcated from the outer fibrous layer by a continuous basement membrane. This cyst appears to have originated from a leptomeningeal neuroglial heterotopia and may represent a continued proliferative growth rather than degenerative change of the heterotopia.

Adult↗

PubMed1987

Crystalloid bodies in skeletal muscle of hypothyroid myopathy. Ultrastructural and histochemical studies.

Crystalloid bodies in skeletal muscle fibers have been described in myopathic and non-myopathic conditions. They have been interpreted as viral, glycogen, protein-glycogen complex, artifacts and of unknown nature. This report described similar crystalloid bodies in the postmortem muscle samples of two patients with hypothyroid myopathy. The crystalloid bodies were preferentially located in the I band and Z line region and in the subsarcolemmal region closely associated with lipofuscin. Some were present within basophilic bodies. They were formed by parallel filaments of 6-10 nm beaded periodically by electron-dense particles of 10-18 nm in a lattice, hexagonal or parallel-ripple pattern. Merging of filaments of crystalloid bodies into actin filaments of the I band was noted. The electron-dense particles stained strongly with periodic acid-thiocarbohydrazide-silver proteinate method for polysaccharides and were unaffected or partially digested by diastase treatment on the ultrathin sections. The filamentous component was neither stained for polysaccharides nor digested by diastase treatment. It is suggested that crystalloid bodies of muscle fibers are composed of two distinct subunits with particles of glycogen complex attached to filaments of unknown nature.

Amylases↗

PubMed1986

Cerebral Paecilomyces javanicus infection. An ultrastructural study.

A 41-year-old diabetic woman developed Paecilomyces javanicus endocarditis and subsequent cerebral fungal embolism and vasculitis with massive infarction and hemorrhage 6 years after a mitral valve replacement with porcine heterograft. The organism was identified by the culture from the infected brain tissue and aortic valve. Cerebral infection due to fungus Paecilomyces is rare. This report documents the cerebral manifestations of fungus Paecilomyces javanicus and describes for the first time the ultrastructure of such an organism obtained from the infected tissue. Their ultrastructural findings, similar to those described in Paecilomyces farinosus derived from culture, include a double-layered cell wall, a triple unit plasma membrane, abundant cytoplasmic lipid droplets, vacuoles, membranous profiles and septal formation. This report further demonstrates hyphae with packed 50A filaments and granulofibrillary material and features suggestive of intrahyphal hyphae, not previously described in fungus Paecilomyces.

Adult↗

PubMed1986

Hirano body in an inflammatory cell of leptomeningeal vessel infected by fungus Paecilomyces.

An intracytoplasmic microfilamentous lattice, ultrastructurally identical to Hirano body, was found in an inflammatory cell within a leptomeningeal vessel wall infected by fungus Paecilomyces javanicus. The structure was well preserved and not associated with phagosomes. This is the first report of Hirano body found in an inflammatory cell at the site of fungal infection. The present finding suggests that the formation of Hirano body is non-specific and not restricted to the cell of the neuro-muscular system.

Adult↗

PubMed1986

Abnormal cilia in a fourth ventricular ependymoma.

Although the luminal surface of the ependymal cells of the human ventricular system is characterized by the presence of cilia with a typical 9 + 2 arrangement of microtubules, cilia are usually described as sparse or absent in ependymal cells of ependymomas. The incidence of aberrant cilia and structurally abnormal cilia in normal ependymal cells and ependymomal cells has not been documented. This report describes detailed ultrastructural and quantitative studies of cilia of the ependymal cells of a fourth ventricular ependymoma in a 5-year-old boy. Of a total of 267 cilia studied, 50% were located in the extracellular microrosettes, 30% in the intracytoplasmic lumina and 20% in the cytoplasm. Thirty precent of all cilia studied showed structural abnormalities. Those present in the aberrant locations, e.g., intracytoplasmic lumina and in the cytoplasm, had a higher incidence of abnormality. Ciliary abnormalities fell into four majors categories: (1) cilia with abnormal axial microtubules, (2) compound cilia, (3) swollen cilia, and (4) cilia with dynein arm defect. Of these, addition, deletion and disorganization of axonemal microtubules were most common. The present study suggested that ciliary abnormality is common in ependymoma and may represent another example of oncogenetic effect on the ciliogenesis of ciliated epithelium.

Cerebral Ventricle Neoplasms↗

PubMed1986

Ultrastructure of cerebellar capillary hemangioblastoma. V. Large pinocytic vacuolar bodies (megalopinocytic vesicles) in endothelial cells.

Large pinocytic vacuolar bodies (megalopinocytic vesicles) containing electron-dense granulo-fibrillary material, not previously described in micro-vascular endothelium of brain tumors, were observed in endothelial cells of all five cases of cerebellar hemangioblastoma studied ultrastructurally. They were present in 23% of a total of 132 capillary profiles studied. Some were prominent and aggregated to occupy a large portion of the endothelial cytoplasm. Unlike the ordinary pinocytic vesicles in endothelial cells, they were distributed predominantly in the vicinity of the nucleus and surrounded by abundant organelles. They were irregular and usually several times larger than macropinocytic vesicles. The larger vacuolar bodies were often surrounded by bundles of microfilaments which often anchored on their limiting membrane. They coexisted frequently with Weibel-Palade bodies and occasionally fused with them. Convergence of coated vesicles and micropinocytic vesicles with the vacuolar bodies was present. However, there was no direct contact between the vacuolar bodies and Golgi apparatus, rough and smooth endoplasmic reticulum and mitochondria. The vacuolar bodies were closely associated with pericytic foot processes. It was suggested that they were formed by invagination of the abluminal cytoplasmic membrane with engulfed extracellular material and migrated internally. Discharge of their contents into the vascular lumen and interendothelial space was observed. Some had a disrupted membrane with a suggestion of release of contents into the cytoplasmic matrix. Their function is unknown, but they may serve as a specific vehicle of transport or digestive mechanism in microvascular endothelium under certain pathophysiological conditions, such as neoplasm, to meet the increasing metabolic demands.

Adolescent↗

PubMed1986

Ultrasonic features of two cases of spinal cord hemangioblastoma.

Two patients with proven intramedullary spinal cord hemangioblastomas were examined with intraoperative ultrasound. The ultrasonic features of a hyperechoic intramedullary mass accompanied by nearby cysts and, in one case, by a syrinx correspond with well-known pathological and computed tomographic descriptions of these tumors. Ultrasonic guidance enabled the surgeon to identify the exact location of the tumors and to proceed with the surgery, limiting the dissection to the area detected. The ultrasound also revealed cysts associated with the tumors, thus providing valuable information to guide the progress of surgery.

Adolescent↗