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Biomedical subjects

S Q Guo

Publications and source records attributed to S Q Guo.

15 recordsLinked to original sources
PubMed1999

Subcellular membrane impairment and application of phospholipase A2 inhibitors in endotoxic shock.

The study aims at elucidating the mechanism involved in the cell dysfunction or impairment and the protective effects of phospholipase A2 (PLA2) inhibitors in endotoxin shock. Thirty-four rabbits were divided randomly into four groups: (1) normal control group (NC, n = 6), receiving saline intravenously; (2) endotoxin shock group (ES, n = 12), receiving 3 mg/kg of E. coli endotoxin; (3) chloroquine pretreated group (CQ, n = 8), receiving 3 mg/kg of chloroquine 3 min before endotoxin injection and (4) chlorpromazine pretreated group (CPZ, n = 8), receiving 0.3 mg/kg of chlorpromazine 30 min before endotoxin injection. Hepatic mitochondria were extracted either 8 h after commencement of the experiment or when the animals died for detecting PLA2 activity, membrane fluidity, membrane bound succinate dehydrogenate (SDH) and malondialdehyde (MDA). Mitochondria of the lung, heart and kidney were also used for detection of the membrane fluidity. It was revealed that the survival rate of 8 h was 100% (NC), 58% (ES), 87.5% (CQ) and 75% (CPZ), respectively. Mean arterial pressure (MAP) dropped soon after endotoxin injection and descended continuously afterwards in the ES group (P < 0.01). Fluorescence polarization, microviscosity and anisotrophy with a DPH probe were elevated above control levels (P < 0.01). SDH was decreased obviously following endotoxin infusion (P < 0.01). Chloroquine and chlorpromazine, serving as PLA2 inhibitors, could abate cellular dysfunction and increase survival rate. It is proposed that PLA2 plays a pivotal role in cellular injury in endotoxin shock. PLA2 inhibitor might serve as a useful adjunct in combating sepsis and shock.

Animals↗
PubMed1994

Giant solitary synovial chondromatosis.

The purpose of this report is to describe giant solitary synovial chondromatosis, a previously unrecognized feature of synovial chondromatosis that may histologically and radiographically mimic a malignant neoplasm. Giant solitary synovial chondroma is an intra- and/or extraarticular lesion measuring over 1 cm in size and sometimes as large as 20 cm. The radiographic appearance is that of a large, well-marginated mass either of irregular feathery calcification from coalescence of multiple small synovial chondromas, or a rounded calcified mass from the growth of a single synovial chondroma. Radiographically, giant solitary synovial chondromatosis may appear similar to chondrosarcoma and parosteal osteosarcoma.

Adult↗
PubMed1994

Enhanced immunogenicity in mice with hepatitis B vaccine complexed to human hepatitis B immunoglobulin.

Purified human hepatitis B immunoglobulin (HBIG) was complexed to plasma derived hepatitis B vaccine (HBVac) at different concentrations and used to immunize Balb/c mice. An enhanced humoral immune response was observed when HBVac was complexed to HBIG in excess of antigen, compared to that immunized with the vaccine alone. Proliferation of splenic lymphocytes was detected when mice were immunized with HBIG complexed to HBVac (0.2-1 microgram), whereas in mice immunized only with HBVac at one microgram, no lymphocyte proliferation was observed. The enhanced immunogenicity of HBIG: HBVac is T cell dependent. The importance of using critical ratio of HBIG and HBVac is indicated, and future application of this complex for vaccination of low- or nonresponders to the present HBVac, as well as for treatment of chronic hepatitis B patients is discussed.

Animals↗
PubMed1993

Diagnosis of eosinophilic granuloma of bone by fine-needle aspiration with concurrent institution of therapy: a cytologic, histologic, clinical, and radiologic study of 27 cases.

Twenty-seven patients with eosinophilic granuloma (EG) of bone seen at our institution between 1979 and 1991 underwent fine-needle aspiration (FNA) with or without concurrent Tru-Cut biopsy. The 16 males and 11 females ranged in age from 2 1/2 to 61 years (median, 10 yr). Twenty-four patients had monostotic lesions. The clinicoradiologic differential diagnosis included osteomyelitis and Ewing's sarcoma (young patients) and primary and metastatic malignancies (older patients). Twenty-four of 28 FNAs (one patient had two FNAs) were diagnostic of EG, and 10 cases were diagnosed by FNA alone. Smears in these cases showed histiocytes, often with grooved or infolded nuclei, and abundant eosinophils. Multinucleated giant cells, foamy histiocytes, neutrophils, lymphocytes, and plasma cells were present in variable numbers. Four FNAs were misdiagnosed: two as osteomyelitis where smears contained abundant neutrophils, sparse eosinophils, and histiocytes misinterpreted as foamy histiocytes, and two as metastatic carcinoma (in adults) where histiocytes in a scant specimen (one case) and skin appendiceal structures without lesional tissue (one case) were misinterpreted. These cases were correctly diagnosed on repeat FNA (one case), Tru-Cut (two cases), or excisional biopsy (one case); however, three cases diagnosed by FNA had nondiagnostic concurrent Tru-Cut biopsies. Treatment consisted of intralesional injection of 125 mg of methylprednisolone (22 cases). Progressive or complete healing of all lesions occurred. FNA is a rapid and useful technique for the immediate diagnosis of EG that allows concurrent institution of therapy.

Adolescent↗
PubMed1992

Chondrosarcoma: MR imaging with pathologic correlation.

Magnetic resonance (MR) images of 21 surgically confirmed chondrosarcomas were retrospectively reviewed in conjunction with plain radiographs and computed tomographic scans and correlated with pathologic findings. The tumors appeared lobulated, and signal intensity, as analyzed visually (intermediate on T1-weighted, high on T2-weighted images), was similar for all lesions, regardless of pathologic type. Size of lesion was not an indicator of grade. The appearances of mesenchymal and dedifferentiated chondrosarcomas mimicked that of conventional chondrosarcoma. Extraskeletal chondrosarcoma was visualized as a lobulated soft-tissue mass. In all cases, MR imaging accurately depicted intraosseous and soft-tissue extent of tumor noted at surgery and pathologic examination. Histologic type or grade of chondrosarcoma generally cannot be characterized on the basis of visual analysis of signal intensity noted on routine MR images. However, MR imaging is excellent for exact delineation of tumor extent.

Bone Neoplasms↗
PubMed1989

Association of microneme antigens of Plasmodium brasilianum merozoites with knobs and other parasite-induced structures in host erythrocytes.

The localization of Plasmodium brasilianum antigens, common to merozoite micronemes and parasite-induced structures in the host erythrocyte, was determined by means of immunogold electron microscopy and monoclonal antibodies directed against blood stages of this parasite. All monoclonal antibodies reacted with micronemes. In addition, some reacted with either knob protrusions or caveolae of the host erythrocyte membrane; one reacted with a parasite-derived antigen present in the erythrocyte cytoplasm. Gold particles appeared over the membranes of ring-infected cells before the appearance of knobs and caveolae. We hypothesize that at least some knob- and caveolae-associated antigens of P. brasilianum are inserted into the erythrocyte membrane at the time of merozoite invasion.

Animals↗
PubMed1989

Down syndrome. Clinical review of ocular features.

A total of 187 medical records of Down syndrome individuals over a 10-year period were reviewed retrospectively for strabismus, myopia, hyperopia, astigmatism, nystagmus, cataract, glaucoma, and other significant eye findings. This study showed that a higher proportion of these individuals than reported in previous studies had strabismus (57%). Refractive errors of myopia (22.5%), hyperopia (20.9%) and astigmatism (22%) were common. The primary care physician needs to be aware of the specific eye problems of Down syndrome individuals so that he or she may initiate or refer the patient for appropriate ophthalmologic care, because most of the eye findings in Down syndrome are treatable. Significant visual loss, a usually avoidable event in Down syndrome, should occur rarely.

Adolescent↗
PubMedDate not supplied

MRI of extraskeletal osteosarcoma.

We report four cases of extraskeletal osteosarcoma of the thigh to illustrate MRI findings of this rare neoplasm. Calcifications or osteoid material were not discernible in these tumors on MRI or conventional radiography. Three tumors were well demarcated on MRI and corresponded to pseudoencapsulation on radiologic-pathologic correlation. These three tumors were heterogeneous in appearance and were hyperintense to muscle on T1-weighted imaging and demonstrated high signal intensity on T2-weighted imaging. In the fourth tumor, which occupied almost the entire thigh, MRI before and after intravenous gadopentetate dimeglumine administration revealed cystic, hemorrhagic, and solid components. Pathological examination revealed a cystic hemorrhagic cavity containing necrotic and viable tumor and a large solid tumor component. The MRI findings in extraskeletal osteosarcoma are non-specific. However, in the appropriate age group the differential diagnosis of a soft-tissue mass in the thigh should include extraskeletal osteosarcoma, even in the absence of radiographically discernible calcifications or osteoid material within the soft-tissue mass.

Aged↗
PubMedDate not supplied

Visual pathway abnormalities in albinism and infantile nystagmus: VECPs and stereoacuity measurements.

The visual pathway of albinos is characterized by abnormal optic nerve fiber decussation with increased contralateral projection. This results in hemispheric asymmetry of monocular visually evoked cortical potentials (VECPs) and may be related to lack of stereopsis. Flash VECP, Random Dot E (RDE), and Titmus stereotest data were collected from 40 nystagmus patients, 19 albino and 21 with normal pigmentation. Data were compared with results obtained from 19 race- and age-matched normal subjects. All albino patients demonstrated hemispheric VECP asymmetries exceeding +/- 2.0 standard deviations from the normal mean, showing either delayed ipsilateral P latency (88%), reduced ipsilateral P amplitude (59%), or both (47%). None of the normally pigmented infantile nystagmus patients exceeded this criteria on either VECP measure. While only one albinotic patient showed positive RDE and stereofly results, 86% of normally pigmented nystagmus patients passed the stereofly test, 60% demonstrated 400 sec (Titmus) stereopsis, and 66% showed positive RDE results. These findings reveal that normally pigmented infantile nystagmus patients have variable degrees of stereopsis and no excessive abnormalities of optic nerve fiber decussation as evidenced by flash VECP. Additionally, this study verifies visual pathway abnormalities and the lack of stereopsis in albino nystagmus patients.

Albinism↗