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Biomedical subjects

L Ma

Publications and source records attributed to L Ma.

At least 577 records · Page 32Linked to original sources
PubMed1987

Orbital reconstruction with proplast.

Proplast was implanted in 15 cases of orbital reconstruction. Seven cases were orbital floor fractures, four cases were phthisical enophthalmos, and four cases were anophthalmic enophthalmos. In orbital floor fracture cases, thin (2-mm) Proplast was placed onto the fractured orbital floor after the incarcerated orbital tissue was released. To correct the enophthalmic socket, Proplast was shaped into small pieces (10 x 5 x 2 mm), then inserted into the subperiosteal space from all directions to fill up the orbital cavity. The results of these 15 cases were satisfactory. The average follow-up period is 13 months. The increased orbital volume seems less than the volume of the implanted Proplast; therefore, we suggest an 80-90% overcorrection rate in accordance with the computer measurements. In sum, Proplast serves as a very good material for orbital floor reconstruction and volume replacement.

Adolescent↗
PubMed1987

Localized amyloidosis of the ureter.

An unusual case of localized amyloidosis of the ureter is described. Suspicion of the condition was first raised during operation when a frozen section was examined. An unnecessary nephrectomy was thus spared. It is a rare condition and awareness of the entity is required to recognise it clinically, radiologically or pathologically. The pathogenesis of localized amyloidosis is briefly discussed.

Aged↗
PubMed1986

Telangiectatic osteosarcoma of the mandible.

A telangiectatic variant of osteosarcoma of the mandible was seen in a 15-year-old Chinese girl. It was first diagnosed as an aneurysmal bone cyst both radiologically and pathologically. There were local recurrences despite repeated surgery, and subsequent response to chemotherapy and radiotherapy was poor. The patient died 16 months later with direct cerebral invasion, but no distant metastases. Diagnostic and clinicopathologic correlative aspects of this tumor variant are discussed, but more study of this tumor variant in the jaw is needed because this is probably the first case fully reported.

Adolescent↗
PubMed1986

Angiosarcoma of the thyroid. An immunohistochemical and ultrastructural study of a case in a Chinese patient.

A case of angiosarcoma (malignant hemangioendothelioma) developing in a chronic goitrous thyroid gland of an elderly Chinese woman is described. Histologically it showed the same classical appearance of angiosarcoma occurring in the skin and soft tissue. The endothelial origin of this tumor was confirmed by demonstrating Factor VIII-related antigen in the neoplastic cells with the immunoperoxidase technique and Weibel-Palade bodies by electron microscopic study. Because of its extreme rarity outside the European Alpine regions, many authorities are reluctant to accept it as a distinct entity and merely consider it as a variant of an undifferentiated carcinoma. Our report not only provides additional evidence that angiosarcoma of the thyroid gland is a specific condition of endothelial origin but also documents the first case among Chinese.

Aged↗
PubMed1986

Endogenous microbial dissemination following severe burns in rats.

This study suggests that damage to the intestinal lining, an important mechanical barrier against bacterial invasion, is the main factor leading to the dissemination of endogenous microbes. Reduced phagocytic activity of Kupffer cells and compromised opsonic function also appear to contribute to the process.

Animals↗
PubMed1986

Anorexia nervosa in a woman totally blind since the age of two.

A 28 year-old woman, blind since the age of two, had become anorexic at 21. She had eating problems as a child, and weight preoccupation from her teens onwards. Psychiatric admission with other anorexic patients preceded the illness. Inability to see oneself does not protect against anorexia nervosa.

Adult↗
PubMed1986

Infantile hemangioendothelioma of the liver: ultrastructural study of a type II case.

A case of infantile hemangioendothelioma of the liver presenting with congestive heart failure and massive hepatomegaly in a two-mth old baby is described. Serum alpha-fetoprotein was elevated in this patient and clinically the lesion might not be distinguishable from other, commoner hepatic tumours in children. Histologically the tumour showed a type II pattern as defined by Dehner. The significance of classifying this tumour into two histologic types is discussed. Only 3 cases reported in the English literature were studied by electron microscopy; two of them were type I while the other was a type II lesion. In our case the endothelial cells appeared ultrastructurally less differentiated and architecturally more disorganized than in type I lesions. Like the previous case, the basal lamina showed marked thickening and reduplication. The significance of these findings is discussed.

Basement Membrane↗
PubMed1986

Myxoma of the breast: report of a case and ultrastructural study.

A case of myxoma of the breast is presented. The differential diagnosis with respect to other myxoid tumours of the breast is discussed. Ultrastructurally the tumour cells show features of a primitive mesenchymal cell with possible pericytic or modified myoepithelial cell differentiation. The histogenesis is discussed.

Breast Neoplasms↗
PubMed1986

Propagation of hepatitis A virus in human diploid fibroblast cells.

Human hepatitis A virus (HAV) was propagated in human diploid fibroblast cultures (2BS cells) in vitro. Replication of the virus was followed by immunofluorescent staining (IF), indirect ELISA, and by immune electron microscopy. When 2BS cells were inoculated with faecal extracts containing HAV, synthesis of hepatitis A antigen (HAAg) could be detected in the cytoplasm by IF. Its concentration reached a maximum at four weeks post-inoculation. Measured by solid-phase indirect ELISA, the positive/negative (P/N) ratio for HAAg reached values of up to 7.7. The identity of newly synthesized virus particles with HAV was established by immune electron microscopy, IF-blocking, and neutralization with human convalescent serum. Infected cells showed no signs of a specific cytopathic effect. Two of the virus strains propagated in 2BS cells may prove useful as a source of antigen for serologic tests; one of them might be a candidate strain for HAV vaccine.

Antigens, Viral↗
PubMed1986

Endo- and exovesiculation and the structure of the human red cell membrane.

Experiments were designed to study functional associations of proteins in human red cell membranes as the membranes are induced to undergo the critical membrane events of invagination or evagination followed by constriction and fusion. Three examples were chosen for study: the inside-out vesicle (IOV) produced in white ghosts by hypotonic removal of cytoskeletal proteins; the endocytic vacuole produced in white ghosts by incubation with Mg-adenosine triphosphate; and the exocytic vesicle produced by metabolic depletion of intact red blood cells. The resulting particles were harvested, and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis for membrane protein content and by enzymic analysis to detect the presence or absence of the exofacial enzyme acetylcholinesterase (ACE), the cytosol facing enzyme glyceraldehyde phosphate dehydrogenase (GAPD), and the integral protein adenosine triphosphatases (ATPases). Each of the vesicles is variably depleted of spectrin and actin, and each retains the exofacial enzyme ACE as well as Mg-ATPase. These findings suggest that there must be local partial depletion of cytoskeletal proteins before invagination or evagination occurs and that in each case part of the exoface of the membrane containing ACE is carried along into the resulting vesicle. The two forms of endocytosis differ with regard to their ATPase content with the energized endocytic vacuole retaining Ca-Mg-ATPase and actin-activated ATPase. The large amount of hemoglobin present in the exocytic vesicle is best explained by trapping of free cytosol and probably reflects a direct interaction of cytosolic components containing hemoglobin with the phospholipid bilayer.

Acetylcholinesterase↗
PubMed1986

Studies on the effect of vanadate on endocytosis and shape changes in human red blood cells and ghosts.

When amphipathic cationic drugs are added to intact human RBCs, the RBCs first undergo a stomatocytic shape change and then, if relatively large amounts of drug are added and if the metabolic state of the RBC is appropriate, endocytic vacuoles form. Vanadate has a structural similarity to the transition state of phosphate, which presumably accounts for its ability to inhibit phosphohydrolases, although other actions of vanadate have been described. Vanadate inhibited three forms of drug-induced endocytosis in intact RBCs despite the fact that the three drugs chosen (primaquine, chlorpromazine, and vinblastine) are known to have differing requirements for RBC ATP. Vanadate also inhibited the stomatocytic shape change produced by primaquine, chlorpromazine, and vinblastine, but not the stomatocytosis produced by low pH. Vanadate had no effect on RBC echinocytosis produced by lysophosphatidylcholine. In studying endocytosis in hypotonic, leaky, "white" ghosts, we discovered that vanadate inhibited only the endocytosis produced by Mg-ATP and not the endocytosis produced by manipulations that directly attack the cytoskeletal proteins. These findings suggest that ATP hydrolysis has a role in some forms of amphipathic cation-induced stomatocytosis and endocytosis in intact RBCs. In addition, studies in ghosts support the idea that Mg-ATP does indeed produce "energized" endocytosis dependent on utilization or hydrolysis of ATP.

Adenosine Triphosphatases↗
PubMed1985

T suppressor lymphocytes reverse ongoing acute allograft rejection.

(LEW X BN)F1 cardiac allografts are rejected within 8 days in untreated LEW recipients. At the critical time point of 5 days after transplantation, the obviously rejecting grafts are enlarged and maximally infiltrated by host cells as shown by 111In-labeled lymphocyte tracer studies. However, when such hearts were retransplanted back to naive (LEW X BN)F1 secondary hosts, they survive indefinitely, showing that even late rejection is reversible in the absence of sustained host immunological drive. Attempts were then made to abrogate this advanced immune responsiveness using Cyclosporine (CsA). CsA therapy (15 mg/kg/day for 7 days) starting from day 5 produced indefinite graft survival, similar as if initiated at the time of operation. Addition of exogenous IL-2, which drives the proliferation of Tc, could not reverse this effect. Serial changes in phenotype of lymphocyte subpopulations infiltrating both acutely rejecting and indefinitely functioning cardiac allografts in unmodified and CsA treated hosts, respectively, were then studied. Ratio of Th:Tc/s cells in acutely rejecting grafts was 1.6 by day 3; it inverted abruptly to 0.7 by day 5-6, suggesting predominance of Tc/s during the later stages of allograft rejection. Similarly, treatment with CsA produced a transient depression of Th, with recovery of original Th:Tc/s ratio during the next 2-3 weeks. Adoptive transfer experiments were then performed to investigate the functional significance of these findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗