Biomedical subjects

Z Gao

Publications and source records attributed to Z Gao.

At least 181 records · Page 10Linked to original sources

PubMed1993

Nude mouse interim host model for human parathyroid grafts. Part III. Mechanism of modification of allograft antigenicity.

The alterations of number and DR antigen expression of antigen presenting cells (APCs) in human PTG grafts during the interim hosting period were analyzed. The results were as follows: 1) In C-PTG grafts, the APC number was reduced obviously within 100 days in the interim host. In F-PTG and A-PTG grafts, the APC number was increased at 30 d of interim hosting, and then decreased gradually. 2) No obvious change in D-related (DR) antigen expression of individual APCs was seen in C-PTG and F-PTG grafts. In A-PTG grafts, DR antigen expression was increased at 30 d of interim hosting, but then dropped gradually and asynchronously.

Animals↗

PubMed1993

Nude mouse interim host model for human parathyroid grafts. Part IV. Human PTG xenograft rejection in a mouse B lymphocyte system.

An interim host model for human parathyroid gland (PTG) grafts has been established. In this experiment, the proliferation of mouse blood vessels and infiltration of mouse B lymphocytes into human PTG grafts were successively observed. The results showed that within 10 d of interim hosting, when PTG grafts were still nourished by permeable factors, scattered mouse B lymphocyte infiltration was already apparent. As time went by, B lymphocyte infiltration and IgG secretion became more obvious. At 60-90 d interim hosting, an intact human-mouse tissue "chimera" was formed. Thereafter, human PTG grafts were gradually fragmented and absorbed. The theoretical significance and clinical value of this rejection phenomenon are discussed.

Animals↗

PubMed1993

Comparison of parathyroid donor grafts.

We compared the degrees of cell maturity, antigenicity and secretory function of parathyroid tissues (PTG) from cadavers (C-PTG), 20-28 week fetuses (F-PTG) and PTG adenomas (A-PTG). In A-PTG, scattered or clustered immature cells were observed, but there were none in F-PTG and C-PTG tissues. A-PTG and C-PTG exhibited better secretory function than did F-PTG. No clear differences were found in HLA class I (ABC) antigen quantity among the three donor PTG tissues, but the amounts of HLA class II (DR) antigen in A-PTG and F-PTG were significantly lower than that in C-PTG. The results demonstrate that C-PTG, with its functional advantages, and F-PTG, with its relatively low antigenicity, can be used in clinical transplantation, while A-PTG tissues are not suitable for clinical transplantation on account of their immaturity and the possibility of carcinomatous change.

Adenoma↗

PubMed1992

Secretion of the STA3 heat-stable enterotoxin of Escherichia coli: extracellular delivery of Pro-STA is accomplished by either Pro or STA.

The methanol-soluble, heat-stable enterotoxin of Escherichia coli is a protease-resistant extracellular peptide which is synthesized as a 72-amino-acid precursor Pre-Pro-STA3. The specific roles of Pre (19 amino acids), Pro (34 amino acids) and STA3 (19 amino acids) in the secretion process were studied by functionally deleting each of the three domains. Deletion of the Pre signal sequence resulted in a short-lived cell-associated molecule with an M(r) equivalent to that of Pro-STA3. Deletion of Pro (i.e., Pre-STA3) resulted in the rapid extracellular accumulation of STA3; the periplasmic intermediate found in the secretion of the wild-type toxin was undetected. Deletion of the STA3 domain resulted in a cell-associated Pre-Pro peptide; with time this form converted to periplasmic Pro which later became extracellular. When DNA encoding either STA3, by itself, or Pro-STA3 (lacking the signal peptide) was expressed, these peptides were degraded intracellularly, with no periplasmic or extracellular forms detected. The results presented demonstrate that the signal peptide (Pre) is essential even for the export of small peptides to the periplasm, and that its absence causes the STA3 domain to become susceptible to intracellular proteases. The rapid degradation of intracellular STA3 indicates that its proteolytic resistance is acquired in a compartment other than the cytoplasm. The results also show that after the Pre domain is proteolytically cleaved from Pre-STA3 and Pre-Pro, the STA3 and Pro peptides can exit to the culture supernatant.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗

PubMed1992

Patterns of phenotypic expression of human junctional, gingival and reduced enamel epithelia in vivo and in vitro.

Epithelia differ regionally in their patterns of phenotypic expression. The junctional epithelium (JE) that attaches the oral mucosa to the teeth is a unique tissue that shows a pattern of differentiation unlike other oral epithelia and forms basal lamina against the non-vital tooth surface. The mechanisms that establish this unusual phenotype and the developmental origin of this epithelium are both uncertain. The formation of JE by downgrowth of the oral gingival epithelium (OGE) during tooth eruption has been suggested but morphological studies indicate that it may be derived from the reduced enamel epithelium (REE) that covers the crown of the unerupted tooth. These epithelia of potential origin differ in their developmental histories: intrinsic differences between them could thus significantly influence the phenotype of an epithelium formed from them. The patterns of phenotypic expression of specimens of dissected JE, OGE and REE, and of cell cultures of these epithelia grown under standardized conditions, were examined (1) by immunocytochemistry using monoclonal antibodies with specificity for individual cytokeratins, vimentin and ICAM-1, and (2) by two-dimensional SDS-PAGE and immunoblotting. The results indicated that, in vivo, OGE expressed keratin markers typical of differentiating mucosal epithelium; JE and REE, in contrast, lacked expression of most such markers but expressed keratins typical of simple epithelia together with some undefined keratin peptides. All epithelia showed changes in vitro but OGE remained different from JE and REE. OGE lost expression of the differentiation markers K1, K10 and K13; it acquired some expression of K19, but less than JE and REE. Cultures of JE and REE retained some expression of ICAM-1 and K8 and K18, and consistently acquired high levels of vimentin expression. These findings indicate that differences persist in standardized culture conditions and that these are apparently of an intrinsic nature. They support a concept of the origins of JE from REE and suggest that the unusual in vivo phenotype of JE results partly from intrinsic differences acquired during its development.

Cell Differentiation↗

PubMed1992

Nude mouse interim host model for human parathyroid grafts. I. Structure and secretory function.

Human parathyroid (PTG) tissues from cadaver (C-PTG), fetus (F-PTG) and PTG adenoma (A-PTG) were transplanted into the kidney subcapsule of Balb/C nude mice as interim host. The structure and secretory function of the tissues were checked 30, 60, 90, 120, and 150 days after operation. The results showed that PTG tissues from all three donors could retain their structure and secretory function for more than 100 days in the nude mice. The growth and function of PTG tissues from the three donors in nude mice were compared.

Adenoma↗

PubMed1992

Nude mouse interim host model for human parathyroid grafts. II. Alteration of MHC antigens in human PTG grafts in the nude mouse.

Human parathyroid (PTG) tissues from cadaver (C-PTG), 5-month fetus (F-PTG) and PTG adenoma (A-PTG) were transplanted into the kidney subcapsular areas of Balb/C nude mice as interim host. Dynamic changes in the amount of tissue major histocompatibility complex (MHC) antigen present within the transplantation period were observed. The results showed that during 100 days of interim hosting, no obvious changes in the expression of tissue MHC class I antigens were seen, but the expression of tissue MHC class II antigens was significantly reduced. The changes of MHC antigens in different donor human PTG tissues were compared.

Adenoma↗

PubMed1992

Evidence for the interaction between antacid and gastric mucosa using an "artificial stomach" model including gastric mucosa.

In light of evidence that certain aluminum-based antacids adhere to the gastric mucosa, we modified our previously described "artificial stomach" (AS) model by including a piece of hog stomach and compared the antacid activity of six aluminum-containing antacid products in the model with and without gastric mucosa. The activity of three of these, Maalox, Riopan and Supralox, was not significantly different in the two systems. In contrast, the activity of the other three, Aludrox, Phosphalugel and Simeco, was significantly greater with mucosa. Antacid activity of one product from each set (Supralox, Phosphalugel) was evaluated in two in vivo methods in human volunteers. For both antacids, results in vivo were similar to those obtained with the AS-containing mucosa. Without mucosa, in vivo and in vitro results were dissimilar for Phosphalugel, thus validating the modified AS. The difference between the two sets of antacids can be explained by 1) the fact that the Al:Mg ratio in the set affected by mucosa is greater than that of unaffected antacids, and 2) a weaker antacid load than in unaffected Supralox. We suggest that in an acid milieu, aluminum ions in antacids like Aludrox, Phosphalugel and Simeco are bound to sialic acid residues in mucus glycoproteins, thus retarding the transit of these antacids through both the AS and the real stomach and prolonging their activity in both situations. When the Al:Mg ratio is low or when the amount of antacid salts is large, aluminum ions tend to be buried in complexes, giving them less chance to interact with gastric mucus, so they transit the stomach more quickly.

Adult↗

PubMed1992

[Clinical practice of the diagnostic criteria of schizophrenia of Chinese classification of mental diseases II (CCMD-2) in 1,394 inpatients].

Re-diagnosed according to diagnostic criteria of schizophrenia of CCMD-2 was applied to 1,394 inpatients, who were diagnosed as schizophrenia when stayed the hospital in 1990. As a result, 98.5% of the cases conformed with four items diagnostic criteria of schizophrenia of CCMD-2; 98.7% of the cases conformed with the criteria of symptomatology; 99.4% of the cases conformed with the criteria for the course of illness; 99.8% of the cases conformed with the for the degree of seriousness; 100% of the cases conformed with the criteria of exclusion. Concordant rate in subtype: catatonic type 96.7%, hebephrenic type 92.2%, regressive type 90.9%, paranoid type 90.6%, residual type 50%, atypical type 50%. The must common symptoms were affective disorder (91%), disturbance of association (83.5%), delusion (62.2%). Frequency of other individual symptom were obviously difference, from 76.8% to 2.9%. We consider that diagnostic criteria of the schizophrenia of CCMD-2 is a appropriate for application in both clinical diagnosis and research work.

Adolescent↗

PubMed1991

Epithelial lining of sinus tracts associated with periapical disease: an immunocytochemical study using monoclonal antibodies to keratins.

We examined 30 specimens of mucosal sinus tracts arising in association with periapical inflammation. Immunocytochemistry and a panel of monoclonal antibodies to keratins were used to demonstrate the epithelial lining and its pattern of keratin expression. Half of the specimens were found to have an epithelial lining that was continuous with the mucosal epithelium and showed various degrees of extension into the sinus. The presence of an epithelial lining appeared to correlate with the duration of the sinus tracts. The immunostaining patterns of the epithelial linings were similar to those of the mucosal epithelium near the sinus opening although some differences were found. Proliferating strands of epithelium, presumably derived from the rest of Malassez, were observed deep in the tissues but were not continuous with the epithelial lining. The results suggest that the epithelial lining of sinus tracts is derived not from epithelial rests in the periapical region but from the mucosal epithelium adjacent to the opening of the sinus tract and that the observed changes in the pattern of keratinization are due to the influence of inflammation or of the connective tissue substrate.

Antibodies, Monoclonal↗

PubMed1991

Patterns of cytokeratin expression in human gingival epithelia.

Specimens of human gingiva were collected from teenage and adult subjects and frozen sections were stained with an extensive panel of monoclonal antibodies with defined specificities for individual cytokeratins. The results indicated different and distinctive patterns of keratin expression by the oral gingival, oral sulcular and the junctional epithelia. It was observed that epithelium with staining characteristics of sulcular epithelium extended over the gingival crest onto the oral surface of the gingiva. Junctional epithelium showed the unusual pattern of co-expression of keratins typical of the stratifying and of the simple epithelial phenotypes. The patterns of gingival keratin expression are compared with those of other mucosal epithelia. The findings are discussed in relation to mechanisms that may determine or influence the junctional epithelial phenotype.

Adolescent↗

PubMed1991

[Assessment of Hasegawa's dementia scale for screening and diagnosis of dementia in the elderly].

A sample of 2573 older inhabitants living in Shanghai was investigated on the spot for screening dementia by HDS. Their scale scores on HDS ranged from 3 to 32.5, and the mean score 25.4; according to the 4-grad classification on HDS, 35.3% were classified as normal, 46.3% as borderline, 16.1% as predementia, and 2.3% as definitive of dementia. The assessment by HDS corresponded well with clinical diagnosis of dementia according to DSM-III based on clinical symptoms in 96.3% of 2573 aged. Assessment by HDS was applied to 100 older patients with clinical diagnosis of psychiatric disorders. The scale scores in 76 cases with functional psychiatric disorders and in 24 cases with organic psychosis ranged from 16 to 32.5 and 1 to 28, respectively, and the mean scale score 28.1 and 17.2, respectively. The mean scale score of those with schizophrenia was 29.9, neurosis 30, depression 28.3, SDAT 9.1, MID 15.1, and other dementia 23.6. These results demonstrate that HDS is a practical and valuable tool of assessment for epidemiological, clinical diagnosis and research work to evaluable dementing states of Chinese elderly.

Aged↗

PubMed1991

[Application of facial nerve ENoG and MEP in the diagnosis and prognosis of facial nerve palsy].

Electroneurography (ENoG), an objective electrophysiologic measurement of compound muscle action potentials (CMAPs), is used to assess the integrity of a peripheral motor nerve. This method has been used for many years. In our study using an electrophysiologic instrument (Medelec MS6), the stimulating electrode was placed over the facial nerve anterior to the tip of the mastoid process and was manipulated to obtain the maximum CMAPs amplitude from the frontal muscle. With 30 normal subjects and 20 patients with facial nerve palsy, the results showed that the latencies and amplitudes were different between the two groups. Motor evoked potential (MEP) is a new method. Ipsilateral facial muscles are excited by magnetic stimulation over the scalp when the coil is placed over the parieto-occipital region. Using a magnetic stimulator and EMG instrument (1500C4 DISA), CMAPs from the orbicularis oris and frontal muscle were measured. In 30 normal subjects, the CMAPs were similar in form but of longer latency than those obtained with electrical stimulation (ENoG). In 20 patients with lateral facial nerve palsy due to Bell's palsy, Hunt's syndrome or trauma, the latencies on the lesion sides were apparently longer and the amplitudes much lower than in the normals. Our studies suggest that magnetic stimulation will detect facial nerves in the region inside the temporal bone where they cannot be touched by electrical stimulation from in front of mastoid process. The use of both ENoG and MEP methods together allows for accurate measurement of proximal facial nerve conduction and also provides some quantitative measurement: thus, we can detect conduction block or axonal degeneration early.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

[Pharmacognostical study on the Chinese drug nanshashen].

The Chinese drug nanshashen is taken from a variety of plants. In this paper, 11 kinds of nanshashen derived from 11 plants of Adenophora have been studied in their pharmacognostical characters and microproperties. A key has been compiled based on the experimental results.

Medicine, Chinese Traditional↗

PubMed1991

[On the skinning of radix Adenophorae].

Traditional experience calls for the skinning of Radix Adenophorae. Depending on the chemical compositions, this paper presents a comparative study on the skin, the radix with skin and the skinned radix. The experimental results show that the contents of beta-sitosterol, saponins, amino acids and trace elements are highest in the radix with skin, and that the radix with skin and the skinned radix are similar in the contents of polysaccharides.

Amino Acids↗

PubMed1990

[Chemical constituents of Adenophora stricta Miq].

Four compounds were isolated from the roots of Adenophora stricta. On the basis of spectrometric analysis and physicochemical constants, they were identified as beta-sitosterol, beta-sitosterol-O-beta-D-glucopyranoside, taraxerone and octacasanoic acid respectively. Taraxerone and octacasanoic acid were isolated from the plants of Adenophora for the first time.

Drugs, Chinese Herbal↗

PubMed1990

[Preliminary study of motor evoked potential (MEP) on facial nerve palsy].

Motor evoked potential (MEP) examination is a new method. Ipsilateral facial muscles are excited by magnetic stimulation over the scalp when the coil is placed on the parieto-occipital region. Using magnetic stimulator and EMG instrument (1500C4 DISA), one can measure the CMAPs from orbicularis oris and frontal muscle. In 30 normal subjects, the CMAPs were found to be similar in form but of longer latency than those obtained with electrical stimulation (ENoG). In 20 patients with facial nerve paralysis due to Bell's palsy, Hunt's syndrome or trauma, the latencies on the affected sides were apparently longer and the amplitudes much lower than those in normal ones. Our studies imply that magnetic stimulation can be used to detect facial nerve in the region inside the temporal bone which is not accessible by electrical stimulation. Using ENoG and MEP methods, the proximal facial nerve conduction can be measured somewhat quantitatively, thus one can detect conduction block or axonal degeneration early. It is important not only for the diagnosis but also for the treatment and evaluation of prognosis.

Adult↗

PubMed1989

Cytokeratin expression of the odontogenic epithelia in dental follicles and developmental cysts.

The patterns of cytokeratin expression in the epithelium of 5 dental follicles, 7 dentigerous cysts, 5 odontogenic keratocysts, 3 nasopalatine cysts and an epidermoid cyst have been studies using a panel of monoclonal antibodies. The epithelium of dental follicles and of developmental odontogenic cysts strongly expressed keratins 5 and 19 and showed weaker expression of keratins typical of stratified non-cornified and of simple epithelia. Staining with mAbs against the latter keratins varied with the degree of epithelial differentiation. Nasopalatine cysts strongly expressed simple epithelial keratins and the epidermoid cyst strongly expressed a marker of cornification. Odontogenic cysts thus appear to differ in their pattern of keratin expression from other oral developmental cysts and all derivatives of odontogenic epithelia appear to share similar basic patterns of cytokeratin expression.

Antibodies, Monoclonal↗