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Biomedical subjects

S Tang

Publications and source records attributed to S Tang.

At least 217 records · Page 12Linked to original sources
PubMed1994

Sonographic findings in bladder haematoma.

The medical imaging and clinical histories of three cases of haematoma of the urinary bladder in paediatrics were reviewed retrospectively. The sonographic findings are unique and diagnostic. Three distinctive sonographic features were observed. The haematomas were large, occupying most of the bladder lumen. They showed an echogenic thick, smooth rim and, in two cases, a laminated appearance with concentric layers of alternating hyperechogenicity and hypo-echogenicity.

Child↗
PubMed1994

Expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) on proliferating vascular endothelial cells in diabetic epiretinal membranes.

The present study demonstrated the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), the proliferating status of the neovascular endothelial cells, and the activation of vascular endothelial cells bearing the two cell adhesion molecules in diabetic epiretinal membranes by using double immunofluorescence and APAAP techniques. The results showed that ICAM-1 was detected in 36 out of 40 (90%) proliferative diabetic retinopathy epiretinal membranes, VCAM-1 was found in 32 out of 40 cases (80%); in 21 out of 26 (81%) vascularised membranes the endothelial cells of the new vessels in the membranes were still in a proliferative stage (positive for proliferating endothelial cell marker EN 7/44) and, further, in 20 out of 26 cases (77%) ICAM-1 was detected on the proliferating endothelial cells and VCAM-1 was found in 21 cases (81%). The expression of cell adhesion molecules, especially ICAM-1 and VCAM-1 in diabetic epiretinal membranes suggests that cell to cell interactions may play a significant role in the development of PDR membranes. In particular, the expression of ICAM-1 and VCAM-1 on proliferating endothelial cells indicates the activation of these cells, which is the first critical step for lymphocyte/endothelial cell interactions and the initiation of immune responses. The significance of proliferating status of the neovascularisation in the membranes may be related to the clinical course and prognosis of the disease.

Cell Adhesion Molecules↗
PubMed1994

Proliferation and activation of vascular endothelial cells in epiretinal membranes from patients with proliferative diabetic retinopathy. An immunohistochemistry and clinical study.

In the present study, we investigated the status of proliferation and activation of vascular endothelial cells in epiretinal membranes from patients with proliferative diabetic retinopathy (PDR) by means of immunohistochemical techniques and compared the findings with the main clinical features of the patients. The results showed that of 21 vascularized membranes, 17 (81%) contained proliferating endothelial cells (positive for proliferating vascular endothelial cell marker EN 7/44) and 19 (90%) were positive for endothelial cell activation marker anti-VCAM-1; Furthermore, by using a double-staining technique we found that in 15 of the 17 cases (88%) the proliferating vascular endothelial cells were activated (expressing VCAM-1). Of the 18 type I diabetics, 15 (83%) contained activated proliferating endothelial cells, whereas in the 3 type II patients, only 1 membrane contained activated proliferating endothelial cells, Preoperatively, 18 patients had severe vitreous hemorrhage, among whom 15 (83%) contained proliferating endothelial cells, which were activated in 13 cases, and 16 patients had tractional retinal detachment, among whom 12 contained proliferating endothelial cells, which were activated in 11 cases. In all, 7 patients (33%) had vitreous rebleeding within 8 months postoperatively, whose membranes in 6 cases contained proliferating and activated endothelial cells. In contrast, of the 4 patients who were negative for EN 7/44, none had rebleeding, and of the 6 patients who were negative for EN 7/44 and anti-VCAM-1, only 1 had rebleeding.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Effects of interferon on infant with CMV hepatitis].

Fifty-seven patients with CMV hepatitis, who were within 3 months of age, were treated with interferon from August 1992 to April 1993. They were randomized to be assigned to two groups. There were 30 patients in the therapeutic group, who were given daily interferon 1,000,000 u intramuscularly for 10 days and 27 patients in the control group, who were put on daily vitamin C and inosine therapy intravenously for 10 days. The results showed that there was a significant difference in the aspects of jaundice disappearance, liver and serum SGPT recovery time between the two groups. In the therapeutic group, the average alleviating time of jaundice, hepatomegaly and serum SGPT level after treatment with interferon were 15.26, 29.89 and 14.26 days ahead of those in the control group, respectively. The cure rate at one month and two months after treatment was 43.0% and 90.0% in the therapeutic group, respectively; 18.5% and 48.0% in the control group, respectively.

Cytomegalovirus Infections↗
PubMed1994

Comparison of the incidence of postpartum low back pain in natural childbirth and cesarean section with spinal anesthesia.

BACKGROUND: Many parturients and their obstetricians believe that spinal anesthesia will cause low back pain (LBP). MATERIALS & METHODS: We studied prospectively a total of 160 parturients; 80 of them had cesarean section (CS) with spinal anesthesia and another 80 who had natural childbirth. Incidence of LBP was investigated and compared in these patients before pregnancy, during pregnancy and postpartum. RESULTS: Our result showed that before pregnancy, about one third (33.1%) of the parturients already had LBP and the incidence of LBP seemed to increase during pregnancy. The incidence of LBP decreased gradually postpartum. There was no difference in the incidence of postpartum LBP between the CS with spinal anesthesia group and the natural childbirth group. CONCLUSIONS: We concluded that postpartum LBP could be related to changes during pregnancy and not related to spinal anesthesia.

Adult↗
PubMed1993

Differential contribution by conserved glutamate residues to an ion-selectivity site in the L-type Ca2+ channel pore.

In voltage-gated cation channels, it is thought that residues responsible for ion-selectivity are located within the pore-lining SS1-SS2 segments. In this study, we compared the ion permeation properties of mutant calcium channels in which highly conserved glutamate residues, located at analogous positions in the SS2 regions of all four motifs, were individually replaced. All of the mutants exhibited a loss of selectivity for divalent over monovalent cations. However, the permeation properties of the individual mutants varied in a position dependent manner. The results provide strong evidence that these glutamate residues, positioned at equivalent locations in the aligned sequences, play significantly different roles in forming the selectivity barrier of the calcium channel, and are probably arranged in an asymmetrical manner inside the ion-conducting pore.

Amino Acid Sequence↗
PubMed1993

Molecular localization of ion selectivity sites within the pore of a human L-type cardiac calcium channel.

A highly conserved position of negatively charged amino acids is present in the SS2 segments of the S5-S6 linker regions among calcium channels. We report here that replacing Glu residues at this position alters the ion selectivity of the human cardiac calcium channel. Substituting Glu334 in motif I or Glu1086 in motif III with Lys produced mutant calcium channels that permeated sodium ions 10-fold more effectively than barium ions. More conservative changes such as substitution of Glu1086 with Gln or substitution of Glu1387 with Ala also increased sodium permeation through the mutant calcium channels. Sodium currents through the mutant calcium channels could be modulated by dihydropyridines and blocked by external divalent cations. These results suggest that Glu334, Glu1086, and Glu1387 are part of a ring of glutamate residues formed in the pore-lining SS1-SS2 region and are critical in determining ion selectively and permeability of a human cardiac calcium channel.

Amino Acid Sequence↗
PubMed1993

Clinical and immunohistochemical correlation of herpetic keratitis with the expression of HLA-DR antigen.

The corneal buttons after corneal graft of 22 patients with herpetic keratitis were studied (16 male, 6 female; 7-87 years of age). Ten still had active inflammation, while 12 had stabilized by the time of the study. Different degrees of neovascularization were observed in 19 cases. HLA-DR antigen was detected in the corneal epithelium in 7 of 22 cases (32%), in the corneal stroma in 17 of 22 cases (77%), and in the endothelium in 9 cases (41%) by using the immunohistochemical technique. The expression of HLA-DR antigen was more common and more marked in active herpetic keratitis (90%) and in neovascularized corneas (84%). The frequency and density of HLA-DR expression in perforating corneal ulcers were no higher than in other cases, but anterior synechia was accompanied by strong expression of HLA-DR antigen in the corneas. The expression of HLA-DR antigen was not only detected in the peripheral, but also in the central area of the specimens. The cells expressing HLA-DR antigen in corneas were mainly corneal cells. The results showed a close relationship between HSV-keratitis and the expression of HLA-DR antigen, which may be induced during the clinical course of the disease. The expression of HLA-DR might be one of the factors in the recurrent onset of the disease and a significant sign of the prognosis of corneal transplantation for these patients.

Adolescent↗
PubMed1993

Financing health care in rural China: preliminary report of a nationwide study.

One unforeseen consequence of the change from collective to household production in rural China has been that the financial basis of the rural health services has been eroded. The majority of peasants now pay for health care on a fee-for-service basis. A major initiative aimed at the establishment of prepayment schemes for funding rural health services is underway. A nationwide survey which compared health utilization and expenditure under different financing mechanisms was carried out in 1988. This paper presents the preliminary findings of that study. There is evidence that hospital charges were a barrier to inpatient care for those not covered by an insurance scheme. The data were less clearcut with regard to access to outpatient care. There is a need for further study which focuses on poor households and those living in remote villages. The study found that drug charges are an important source of revenue for the rural health services. The impact of this on prescription practices is an area which requires additional research. The cost of rural health services was relatively low. It is feasible to finance them almost entirely out of local resources in the more developed regions. The situation in the poorer provinces is more complicated. In spite of the fact that average health expenditure was almost 5% of household income in 1988, there was evidence of lack of access. This suggests that it may be more difficult to develop prepayment schemes to cover the full range of rural health services in the less developed regions.

China↗
PubMed1993

Molecular localization of regions in the L-type calcium channel critical for dihydropyridine action.

Sensitivity to dihydropyridines (DHPs) is a distinct characteristic that differentiates L-type Ca2+ channels from T-, N-, and P-type Ca2+ channels. To identify regions necessary for the functional effects of DHPs, chimeric Ca2+ channels were constructed in which portions of motif III or motif IV of a DHP-insensitive brain Ca2+ channel, BI-2, were introduced into the DHP-sensitive cardiac L-type Ca2+ channel. The resultant chimeric Ca2+ channels were expressed in Xenopus oocytes, and the effects of a DHP agonist and antagonist were studied. The results show that the linker region between S5 and S6 in motif IV of the L-type Ca2+ channel is a major site for DHP action. The DHP agonist and antagonist molecules interact with distinct sites on the alpha 1 subunit of the L-type Ca2+ channel. The data further show that the SS2-S6 region of motif III is not involved in DHP action but may be an important structural component of inactivation.

Amino Acid Sequence↗
PubMed1993

Characterization and developmental expression of Tlx-1, the murine homolog of HOX11.

HOX11, a human homeobox gene with putative oncogenic potential, was originally discovered at the chromosome 10 breakpoint in T-cell acute lymphoblastic leukemias bearing the chromosomal translocation t(10;14)(q24;q11). To provide insight into the possible roles of this gene in development, we isolated and characterized its murine homolog, Tlx-1, and examined its profile of expression. Tlx-1 transcripts are first detected at E8.5 in the surface ectoderm and central mesenchyme of the first branchial arch. This expression subsequently extends to the 2nd, 3rd, and 4th branchial arches, as well as the presumptive pharynx, as these structures develop. Between E12.5 and E15.5, the profile of Tlx-1 expression becomes more complex; expression is observed in the developing pancreas and salivary glands, as well as in several components of the nervous system, including the trigeminal, glossopharyngeal and vestibulocochlear ganglia, the spinal cord, and the curvature of the pons-medulla. In addition, expression is seen in the pinna and external auditory meatus of the outer ear, the tooth primordia, and specific cell populations of the mandible and tongue. These complex patterns of expression are consistent with multiple and varied roles for Tlx-1 in development and suggest that Tlx-1 marks, amongst other cell populations, structures derived from cranial neural crest cells and migratory paraxial mesoderm that arise at corresponding levels along the rostral-caudal axis of the developing embryo.

Amino Acid Sequence↗
PubMed1993

Cells of the immune system and their cytokines in epiretinal membranes and in the vitreous of patients with proliferative diabetic retinopathy.

In the present study, we specifically investigated the presence of the main immune cells, namely T helper/inducer lymphocytes, T suppressor/cytotoxic lymphocytes, B lymphocytes and macrophages, for HLA-DR antigen expression and the cytokines IL-1 alpha and IL-2 in epiretinal membranes of proliferative diabetic retinopathy (PDR) using immunohistochemical staining. The levels of the two cytokines (IL-1 alpha and IL-2) in the vitreous were measured by ELISA. The results show that 18 out of the 32 epiretinal specimens reacted positively with monoclonal anti-CD4 (marker for T helper/inducer cell subset) antibody (56%), 21 reacted with monoclonal anti-CD8 (marker for T suppressor/cytotoxic subset) antibody (66%), 15 reacted with monoclonal anti-CD22 (marker for B lymphocytes) antibody (47%), and 25 (78%) were positive for monoclonal anti-macrophage and anti-HLA-DR antibodies. IL-1 alpha and IL-2 were detected in the epiretinal membranes in 8 out of 13 tested cases (62%). However, in the vitreous, IL-1 alpha was detected in only 3 out of 13 cases (70, 75 and 80 pg/ml, respectively), while IL-2 was not detected in any of the vitreous samples. The results clearly demonstrate that immune cells and their cytokines were found in about half of the epiretinal membrane specimens. The invasion of the immunocompetent cells in the membranes seems to be a secondary event. They would not participate in the pathogenesis of PDR, but probably induce unspecific reactions and thus complicate the disease.

Antigens, CD↗