[A rat model of tongue mucosa squamous cell carcinoma induced by oral administration of 4NQO in drinking water]

OBJECTIVE

To establish a more realistic animal model for oral carcinogenesis which reveals histological and immunological characteristics similar to the human counterpart.

METHODS

0.002% 4-nitroquinoline 1-oxide (4NQO) in drinking water was administered orally to SD rats for 9-32 weeks. Then the rats were killed and their tongues were removed for histological assessment.

RESULTS

Gross changes included leukoplakia, erosion, ulcer and papillary appearance on the dorsum of the posterior tongue were present during carcinogenesis. Their corresponding histopathological findings ranged from hyperplasia (HP), mild-moderate dysplasia (mmDP), severe dysplasia (sDP) and in situ carcinoma (ISC) to well-differentiated invasive squamous cell carcinoma (SCC). The severity of lesions corresponded to the duration of administration. The tongues in rats treated with 4NQO for 9 weeks showed HP (80.0%) and mmDP (20.0%); those for 13 weeks showed mmDP (66.6%) and sDP (33.3%); those for 16 weeks showed sDP (55.5%) and ISC (44.4%); and those for 32 weeks showed sDP (12.5%), ISC (12.5%) and SCC (75.0%). The incidence of tongue cancer in rats treated with 4NQO for 9 weeks, 13 weeks, 16 weeks and then observed for 32 weeks was 50.0%, 62.5%, and 77.8%, respectively. No metastases were found.

CONCLUSION

4NQO reliably produced preneoplastic and neoplastic tongue mucosa lesions, which morphologically and histologically mimic human oral carcinogenesis. The rat tongue, a target organ of 4NQO, is not an immunologically privileged site like the hamster buccal pouch. Thus, the model should be appropriate to study molecular mechanism of neoplastic transformation and to assess new treatment modalities of premalignant and malignant lesions of the human oral cavity.

An investigation into the supramolecular structure of ternary gel systems using oscillatory rheometry, microscopy, and low frequency dielectric spectroscopy

A series of ternary gel systems based on cetostearyl alcohol (CSA) and cetomacrogol 1000 or sodium lauryl sulfate have been studied using oscillatory rheology, differential interference contrast (DIC) microscopy, cryoscanning electron microscopy (cryo-SEM), and low-frequency dielectric analysis in order to elucidate the nature of the lamellar structures formed in relation to composition. The effects of altering the concentration of CSA (0.25% to 8% w/w) for 1% and 2% w/v cetomacrogol 1000 and 0.5% and 1% w/v sodium lauryl sulfate systems have been investigated, with marked increases in the storage and loss moduli seen on increasing the concentration of CSA for both surfactants. DIC microscopy indicated that at low CSA concentrations, needlelike structures were seen which, on increasing the concentration, were observed to congregate into nuclei. At concentrations of 4% CSA and above, neospherical structures were also observed. Cryo-SEM revealed that the needlelike objects were sheet structures ascribed to lamellar gel phases, while the nuclei were folded "rosettes" formed by those sheets, with the spherical structures being ascribed to cetostearyl alcohol. It was also noted that the lamellae were more tightly folded at 8% w/w CSA, which may be associated with the higher rheological moduli for these systems. Low-frequency dielectric analysis was performed over a frequency range of 10(4) Hz to 10(-2) Hz. A decrease in both the dielectric loss and capacitance was observed as the concentration of cetostearyl alcohol was increased. The dielectric data were described in terms of an equivalent circuit model based on a modified Maxwell-Wagner response. A good correlation was found between the fitted and experimental data and the effect of altering the gel composition on specific features of the equivalent circuit are discussed.

Characterization of the effects of drug addition on the structure of glyceryl monoolein/water gel systems using low frequency dielectric spectroscopy

The influence of propantheline bromide incorporation on the phase structure of glyceryl monoolein/water systems has been investigated using low-frequency dielectric spectroscopy over a frequency range of 10(-2) to 10(6) Hz at 20 degrees C. The responses of glyceryl monoolein systems composed of 10% and 30% w/w were measured and the spectra modeled using an equivalent circuit based on the Maxwell-Wagner theory.1,2 Marked changes in the dielectric responses of the systems were noted on addition of the propantheline bromide at concentrations up to 10% w/w. For the lamellar (10% w/w water) glyceryl monoolein systems, an increase in the imaginary permitivity was seen, corresponding to an increase in conductivity due to the presence of additional ionic species within the system. Evidence was also obtained for the incorporation of the drug directly into the lipid bilayers, particularly at higher concentrations (10% drug) at which dielectric behavior corresponding to bilayer disruption was seen. Incorporation of 3% and 5% w/w drug into the cubic phase systems (30% w/w water) resulted in a change to the lamellar phase. However, circuit modeling indicated that the system formed structures which showed features of both the lamellar and cubic phases at 3% w/w drug loadings. The study has therefore demonstrated that dielectric analysis may provide a novel means of studying the effects of drug incorporation on the phase behavior of complex gel systems.

PrM- and cell-binding domains of the dengue virus E protein

The E-prM proteins of flaviviruses are unusual complexes which play important roles in virus assembly and fusion modulation and in potential immunity-inducing vaccines. Despite their importance, little is known about the biogenesis and structural organization of E-prM complexes. Pulse-chase radiolabeling of dengue virus-infected Vero cells demonstrated a rapid interassociation of E and prM proteins, and sucrose gradient sedimentation analysis suggested that E-prM complexes progressed from simple heteromers to more densely sedimenting structures indicating increased multimerization. E-prM heteromers of even higher complexity were observed in virus particles, suggesting an intracellular assembly process which results in the networking of E-prM subunits into a lattice-like structure found in virus particles. Trypsin cleavage of E-prM-containing virus particles resulted in the release of a soluble 45-kDa fragment of the E protein which retained cell-binding activity. The results suggest that E-prM interactions in dengue virus particles are largely mediated by domains in the carboxy-terminal anchoring domain of E, while cell-binding activity is retained in a trypsin-releasable ectodomain of the E protein.

Selection of quantitative criteria for evaluating metastases of a highly metastatic salivary adenoid cystic carcinoma cell line to the lungs of nude mice

OBJECTIVE

To select reliable quantitative criteria for evaluating metastases of a highly metastatic salivary adenoid cystic carcinoma cell line (ACC-M) cell to the lungs of nude mice.

MATERIALS AND METHODS

The within-group coefficients of correlation of 5 parameters were measured from lung slides using a video image digital analysis system (VIDAS), and the intergroup coefficients of correlation of 6 sets of parameters from all the lungs, which were taken from ACC-M lung metastases models, were calculated and statistically analyzed.

RESULTS

The within-group coefficients of correlation of 5 parameters are as follows: ratio of area of metastases, t = 0.9 (P < 0.001); area of metastases, t = 0.7 (P < 0.05), size of lung section, numbers of metastases, and size of the largest metastatic focus all t < 0.4 (P > 0.05). The intergroup coefficients of correlation of the parameters are as follows: ratio of area of metastases was assigned 1, weight of the lung was 0.9755, and area of metastases was 0.8628.

CONCLUSION

For evaluating lung metastases of ACC-M, the ratio of area of metastases and weight of the lung are precise; the area of metastases is also significant within the 6 quantitative parameters.

Enhanced efficacy of the combination of all-trans-retinoic acid and gamma-interferon in inhibiting proliferation of Tca8113 cells

OBJECTIVE

To develop a more effective induced-differentiation or -apoptosis therapy for treating oral squamous cell carcinomas.

METHODS

The combination of all trans retinoic acid (ATRA) and interferon-gamma (IFN-gamma) was tested for its antiproliferative activity against human tongue squamous cell carcinoma cell line (Tca8113 cells) in vitro. Clonogenic assay, MTT assay, and microscopic cell analysis were performed in this experiment.

RESULTS

The results show that the combination of ATRA and IFN-gamma can produce synergistic antitumor effects, resulting from induction of apoptosis, on Tca8113 cells.

CONCLUSION

The combination of ATRA and IFN-gamma is a more effective induced-apoptosis therapy for treating oral squamous cell carcinoma.

[Effects of laminin on the invasive and metastatic behaviors of human salivary adenoid cystic carcinoma cell lines]

OBJECTIVE

To study the effect of laminin (LN) on invasive and metastastic behaviors of salivary adenoid cystic carcinoma (Acc) cell lines.

METHODS

Immunohistochemistry, Boyden chamber in vitro motility, and adhesion test were used. LN and LNR (LN receptor) distributions in Acc-2 and Acc-M cells were studied with immunohistochemical staining.

RESULTS

There were less LN and LNR found in Acc-2, but much more LN and LNR were present in the highly metastatic clone Acc-M. With the presence of exgenous LN, Acc-2 became activated showing a higher migration rate. The cell adhesion test showed that Acc-2 had stronger ability of adhesion than Acc-M with the presence of LN.

CONCLUSION

The result suggests LN and LNR may play a vitral role in the invasion and metastasis of Acc.

Linkage analysis of the genetic markers of the candidate genes with non-insulin dependent diabetes mellitus in Chinese families

OBJECTIVE

To explore the relationship between the genetic markers of the candidate genes (insulin receptor, glucose transporter 2 and glucokinase) and non-insulin dependent diabetes mellitus (NIDDM) in Chinese pedigrees.

METHODS

Genomic DNA of 87 members in 12 Chinese NIDDM pedigrees was amplified using PCR technique. Denaturing polyacrylamide gel electrophoresis was applied to detect short tandem repeat polymorphisms. The linkage program was used under the models of autosomal dominant and recessive. The individuals with impaired glucose tolerance (IGT) of age < or = 45 and age > 45 were counted as affected and unknown status respectively.

RESULTS

Linkage of insulin receptor gene and NIDDM was strongly and significantly rejected with total LOD score of-infinity (theta = 0.000). Linkage analysis of glucose transporter 2 gave the result with total LOD score of 2.646 (theta = 0.000) in 4 pedigrees. Linkage of glucokinase and NIDDM was of significance with total LOD score reaching 3.150 in the integration of 6 pedigrees.

CONCLUSIONS

Mutations in or near the insulin receptor gene are unlikely to be the major cause of inherited predisposition to NIDDM in Chinese pedigrees that are related in this study, not excluding the principal role in the other Chinese or populations, while the mutations/variations near or at the glucose transporter 2 gene locus might be something of the cause, which needs more data to be ascertained, of familial NIDDM in Chinese pedigrees. However, the variations in or near the glucokinase gene might play a dominant role in the development of NIDDM in some Chinese and represent a subgroup of common NIDDM.

[Acetabular dysplasia:an experimental study]

OBJECTIVE

To demonstrate whether acetabular dysplasia represents a primary feature of congenital dislocation of the hip or secondary defect.

METHOD

The capsule of twelve puppies aged five to nine weeks was incised and the ligamentum teres was completely severed under anaesthesia. A part of gluteal medium muscle was implanted in the acetabulum and the head of the femur was dislocated from acetabulum. Roentagenogram was made three weeks after dislocation in all animals.

RESULT

As early as three weeks after dislocation, acetabular dysplasia was clearly noted in all animals. There was more acetabular obliquity and increase of acetabular index.

CONCLUSION

The acetabular dysplasia is the result but not the cause of congenital dislocation of the hip. This result provides probably support for the concept of developmental dislocation of the hip.

Expression and characterization of deletion recombinants of two cGMP-inhibited cyclic nucleotide phosphodiesterases (PDE-3)

cDNAs encoding two PDE-3 or cyclic GMP-inhibited (cGI) cyclic nucleotide phosphodiesterase (PDE) isoforms, RPDE-3B (RcGIP1) and HPDE-3A (HcGIP2), were cloned from rat (R) adipose tissue and human (H) heart cDNA libraries. Deletion and N- and C-terminal truncation mutants were expressed in Escherichia coli in order to define their catalytic core. Active mutants of both RPDE-3B and HPDE-3A included the domain conserved among all PDEs plus additional upstream and downstream sequences. An RPDE-3B mutant consisting of the conserved domain alone and one from which the RPDE-3B 44-amino acid insertion was deleted exhibited little or no activity. All active recombinants exhibited a high affinity (< 1 microM) for cyclic AMP (cAMP) and cyclic GMP (cGMP), were inhibited by cAMP, cGMP, and cilostamide, but not by rolipram, and were photolabeled with [32P]-cGMP. The IC50 values for cGMP inhibition of cAMP hydrolysis were lower for HPDE-3A than for RPDE-3B recombinants. The deduced amino acid sequences of HPDE-3A and RPDE-3B catalytic domains are very similar except for the 44-amino acid insertion not found in other PDEs. It is possible that this insertion may not only distinguish PDE-3 catalytic domains from other PDEs and identify catalytic domains of PDE-3 subfamilies or conserved members of the PDE-3 gene family, but may also be involved in the regulation of sensitivity of PDE-3s to cGMP.

An investigation into the use of low-frequency dielectric spectroscopy as a means of characterizing the structure of creams based on Aqueous Cream BP

A range of creams based on Aqueous Cream BP have been analyzed using low-frequency dielectric spectroscopy, with accompanying circuit modeling in combination with rheological and microscopic supportive techniques, to explore the use of the dielectric approach as a novel means of characterizing cream systems. Creams based on the formula for Aqueous Cream BP were produced by hand-mixing and mechanical mixing, with and without the inclusion of the preservative phenoxyethanol. Dielectric analysis was performed over a frequency range of 10(-2)-10(5) Hz. Cream samples were also examined using stress scan rheology and differential interference contrast microscopy. Dielectric analysis indicated that the presence of preservative decreased the capacitance and loss of the creams. The responses were modeled in terms of a dispersive capacitance in series with two RC circuits (series and parallel). Rheological studies indicated higher viscosities for the hand-mixed and unpreserved systems. Differential interference contrast microscopy showed marked differences in the distribution of the oil droplets, depending on the method of mixing. The study has demonstrated that dielectric spectroscopy, with accompanying circuit analysis, may be used as a means of modeling the structure of cream systems. The investigation has also shown that the formulation and preparation method of Aqueous Cream BP may have a profound effect on sample structure.

[Virilizing and feminizing adrenal syndrome]

OBJECTIVE

To inquire into diagnosis, differential diagnosis and treatment of virilizing and feminizing adrenal syndrome especially differential diagnosis between benign and malignant of sex hormone producing adrenal neoplasma and treatment principles of congenital adrenal hyperplasia (CAH).

METHOD

Eight cases of CAH and five cases of sex hormone producing adrenal neoplasma were presented during 1986-1996. The former included 3 rare cases of 17 alpha hydroxylase deficiency and others. The latter included 3 cases of feminizing adrenal tumors and 2 cases of virilizing adrenal tumors.

RESULT

Weight and diameter of tumor, DHEA, 17-ks and sex hormone levels, appearance of CT imaging, infiltration and metastasis, were closely related to differentiation of benign and malignant tumors.

CONCLUSION

Some standards are not absolute because of limited practice, follow-up is very important. Adrenal virilizing and feminizing neoplasms were surgically resected by different incision. Modified subcostal incision is recommended as a best choice for huge adrenal mass. Corticoadrenal hormone treatment of CAH should select different kind of corticoadrenal medicine for different kind of CAH. Treatment of sex hormones is not suitable for children suffered from 17 hydroxylase deficiency until prepuberty.

[Molecular biology studies on metalloproteinase and tissue inhibitor of metalloproteinase expression in salivary adenoid cystic carcinoma]

In order to research the relation between metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) and metastasis of salivary adenoid cystic carcinoma (ACC). We use dot blotting to analyse the expression of MMP-2, MMP-9 and TIMP-2 in ACC-2, a cell line of ACC in palate and ACC-M, a high lung metastasis clone which cloned from ACC-2. The result showed the expression of MMP-2 and MMP-9 were higher in ACC-M than that in ACC-2, but the expression of TIMP-2 were higher in ACC-2 than that in ACC-M This suggest MMP-2 and MMP-9 can promote ACC metastasis, TIMP-2 can suppress ACC metastasis. MMP and TIMP maybe a key mechanism of ACC metastasis.

Kinetics of selenium incorporation into tissues of female mallard ducks

Selenium is essential for both mammalian and avian species, although its metabolism in birds has been less thoroughly studied. Little information has been available on the kinetics of selenium in birds, especially as it relates to the teratogenicity seen in waterfowl consuming excessive amounts. This study describes the pharmacokinetics of small amounts of 75Se as selenious acid injected into female mallard ducks. Labeled selenium was injected into a wing vein of restrained animals and tissues taken at five different time points up to 24 h post-injection. Selenium levels as percent of injected dose were determined in liver, kidney, heart, lung, adrenals, thyroid, spleen, pancreas, ovaries, intestine, muscle and plasma. Estimates of kinetic parameters (uptake and elimination rates, time of maximum concentration and maximum concentration) were obtained with a non-linear kinetics computer program (PCNONLIN, SCI Software, Lexington, KY). Results showed four basic patterns of distribution, uptake and elimination. Visceral tissues exhibited a triphasic pattern with a rapid rise, a decline followed by a distinctive increase in levels between the last two time points. Brain uptake was continuous over the 24 h. Plasma rose rapidly and then declined to a constant level. The ovaries as a tissue of interest relating to the teratogenic effects of selenium showed the greatest relative increase at 24 h, suggesting kinetic mechanisms consistent with a pathway that might lead to accumulation of toxic levels and teratogenic effects during embryo development.

[Insulin receptors in diabetes mellitus]

We described the clinical significance of the measurement of insulin receptors and the mechanism of non-insulin dependent diabetes mellitus (NIDDM). Changes in insulin receptor (IR) of red blood cells in 47 patients with NIDDM were compared with those of 28 normal controls. The levels of high and low-affinity IR in the 47 patients with NIDDM were lower than those of normal controls and were prominent in untreated new NIDDM patients. Hyperinsulinemia was not found in these patients, indicating that the low IR is a primary defect not caused by the "down regulation" mechanism. In the IDDM patients the levels of high and low-affinity IR were higher than those of the normal controls, but decreased markedly after insulin therapy, indicating that the "up regulation" is attributable to the high IR levels, other than the primary IR defect.

[Experimental study on antitumor effect in vitro of modified DNL of oral squamous cell carcinoma with TNF-alpha gene]

The gene coding for TNF-alpha was introduced into DNL of human oral squamous carcinoma by retroviral-mediated gene transduction, and experiments proved that the gene had been introduced into the DNL and the DNL could secrete TNF-alpha of high activity with PCR analysis, bioactivity analysis of TNF-alpha, selection test in G418. Cytotoxicity of gene-transduced and nontransduced DNL to Tca8113 cell was compared with MTT method. The result showed that cytotoxicity of the former was higher than that of the latter.

[Effects of SAD on cytogenetics of mouse embryonic cells and its embryo development]

We report here that SAD may not only suppress transcription activity of rRNA genes, but also increase SCE frequency of mouse embryonic cells, leading to bloching of the embryo development and fetal death, and finally significant decrease of birth percentage of the new born offsprings. Ata concentration of SAD in 10(-5)mol/L, the transcription activity of rRNA genes was decreased to 15% of the normal level, and the SCE frequency was increased doubly, leading to that the birth percentage was decreased to 50% of normal one. When SAD concentration of 10(-3)mol/L was used the transcription activity of rRNA genes was completely suppressed and SCE frequency was increased to as 4.8 times high as normal, leading to that the birth percentage dropped to 4% from 100%. Our results indicates that both the cytogenetic effects and the inhibition of the embryonic cells are directly proportional to the SAD concentration used. The relationship between the change of both the rRNA gene transcription and SCE frequency and the degree of embryo development are also discussed preliminarily.

[Role of type IV collagene and type IV collagenase in the invasion and metastasis of salivary adenoid cystic carcinoma]

Using immunohistochemical ABC method, the authors studied the distribution of type IV collagen and type IV collagenase in 25 cases ACC. The result showed type IV collagen was found in vascular and epithelial basement membrance, and in partly cyst of sieve-like and tubular pattern, and in cytoplasm of tumor cell. Type IV collagenase was detected in membrance and cytoplasm of tumor cell. Expression of type IV collagen and type IV collagenase were correlated with pathologic type, TNM stage and metastasis. Much positive staining of type IV collagen was found in sieve-tubular pattern, early stage of TNM and without metastasis, but much positive staining of type IV collagenase was found in solid pattern, later stage of TNM and metastasis. The result suggested that the loss of type IV collagen and over-expression of type IV collagenase may be markers of malignance of ACC.

A synthetic lipopolysaccharide-binding peptide based on the neutrophil-derived protein CAP37 prevents endotoxin-induced responses in conscious rats

The lipid A component of lipopolysaccharide (LPS) derived from Escherichia coli has been implicated as a significant mediator in the development of circulatory and metabolic dysfunction and lethality associated with sepsis. A synthetic peptide corresponding to amino acid residues 20 through 44 of the neutrophil-derived 37-kDa cationic antimicrobial protein (CAP37 P(20-44)) possesses lipid A binding characteristics which may be useful in attenuating in vivo responses induced during circumstances of endotoxemia, including sepsis. The E. coli LPS to be used in the in vivo study was shown to be attenuated by CAP37 P(20-44) in a dose-dependent manner in the in vitro reaction with Limulus amoebocyte lysate. Intravenous infusion of CAP37 P(20-44) (1.5 or 3.0 mg/kg of body weight) with E. coli LPS (250 microg/kg over 30 min) into conscious, unrestrained rats prevented LPS-induced hyperdynamic and hypodynamic circulatory shock, hyperlactacidemia, and leukopenia in a dose-related fashion. CAP37 P(20-44) (0.2, 1.0, and 5.0 mg/kg) administered intravenously to conscious, actinomycin D-sensitized rats following a lethal dose of LPS neutralized LPS toxicity, resulting in dose-dependent 7-day survival rates of 30, 50, and 80%, respectively. CAP37 P(20-44) (5.0 mg/kg) significantly inhibited the endotoxin-induced increase in circulating tumor necrosis factor alpha in sensitized rats. These data demonstrate that CAP37 P(20-44) has the capacity to abolish in vivo biological responses to LPS that are relevant to human sepsis and to significantly neutralize the toxicity of circulating E. coli LPS.

Effect of thiols on fructosamine assay

Fresh human serum, gGAPDH and beta-mercaptoethanol were used to examine the effect of thiols on fructosamine assay. The kinetics of the reaction with both fresh human serum and gGAPDH displayed biphasic behaviour (fast and slow). When the thiols were modified with IAA, the kinetics only demonstrated the slow phase. Since the absorbance increase in the interval from 9 to 10 min was used in the fructosamine assay of glycated human serum we studied the effect of thiols on that measurement. In the case of gGAPDH, the value was approximately one-half of the original after thiol modification, suggesting thiol interference. Nevertheless, gGAPDH may contain a fructosamine structure. beta-Mercaptoethanol itself gave a strong positive result in the fructosamine assay. Hence, thiol groups on glycated proteins should be modified before doing a fructosamine assay because of their substantial interference.

[nm23 expression and its correlation with lung metastasis in human salivary adenoid cystic carcinoma]

The nm23 gene products, nucleoside diphosphate kinase (NDPK), expression in salivary adenoid cystic carcinoma (ACC) was evaluted by using LSAB immunohistochemical method. Of 25 cases tested, 16 (64.0%) showed positive staining, in which, higher incidence of positive staining was found in ACC without lung metastasis (88.2%, 15/17) than in that with lung metastasis (12.5%, 1/8; P < 0.01). Expression of NDPK/nm23 was correlated with the P-TNM pattern (P < 0.05), otherwise it was not correlated with pathologic types (P > 0.05). The result suggest that the nm23/NDPK may play a role in suppressing the metastatic potential in ACC.

[Protective effect of angiotensin coverting enzyme inhibitor on renal function in normotensive non-insulin dependent diabetes mellitus patients with early diabetic nephropathy and microalbuminuria]

Fourty six cases of non-insulin dependent diabetes mellitus (NIDDM) with normotension and microalbuminuria (< 30 mg/24 h) were divided into groups A and B, and observed for about 2 years. Only group A was treated with perindopril 2 mg a day. We found that 2 years later glomerular filtration rate (GFR), effective renal plasma flow (ERPF) and filtration fraction (FF) in the two groups decreased markedly, but GFR and FF decreased more markedly in group B than in group A. Meanwhile, in group A urinary albumin excretion rate (UAER) and insulin sensitivity index (SI) decreased significantly and blood pressure was stable, but in group B UAER and blood pressure elevated significantly and SI was only slightly ameliorated (P > 0.05). The levels of serum triglycerides and cholesterol were not markedly different between the two groups during the 2 years. These results indicate that ACEI may play a role in protecting the renal function in diabetic nephropathy, reduce the risk factors of atherosclerosis and improve SI. It is beneficial to retard the development of diabetic nephropathy and to protect in renal function with small dose of ACEI.

[Observations of cellular differentiation behaviour in adenoid cystic carcinoma of human salivary gland in vitro]

The celluar differentiation behaviour of adenoid cystic carcinoma (ACC) of salivary gland was investigated in vitro with immunohistochemistry. The results showed that the cells of ACC-2 and ACC-3 cell lines can express some marker proteins in vitro including S-100 protein, actin, myosin which is characterized as a feature of myoepithelial cells. When differentiation inducer, dB-cAMP, was added to the monolayer cells cultured in dishes, the marker protein expression increased and the CEA changed to positive. The cellular differetiation behaviour of ACC cells is related to the proliferate speed of cells. Some cells manifested finger ring-like when the culture condition was changed, it means that these cells have the secretory function. If the ACC cells were suspended singly in collagen gels which performed as an extracellular matrix they grew and formed the tubule-like structure. The results will help us to understand the histogenesis of ACC, the source of myoepithelial cells in ACC and the variety of histological structures of ACC.

The central distribution of adrenomedullin and its effects on blood pressure and heart rate in rats

The present study was designed to make certain whether there exists adrenomedullin (ADM) in the rat central nervous system and evaluated the hemodynamic actions of intracerebroventricular administration (ICVA) of human ADM[13-52]. By immunohistochemistry (ABC method). We found that there was a discrete localization of ADM-positive immunoreactivity in the rat central system including cerebral cortex, paraventricular tissues, hypothalamus, cerebella cortex, mesencephalon and medulla oblongata. By reverse transcription-polymerase chain reaction (RT-PCR) analysis, rat ADM mRNA was found to be expressed in rat brain. These above results of immunohistochemistry and RT-PCR suggest that ADM exists in the rat brain. We also found that centrally administered ADM[13-52] in a dose of 0.4 to 3.2 nmol/kg provoked marked, prolonged and dose-dependent increases in mean arterial blood pressure (MABP) and heart rate (HR). To clarify the mechanisms of the hemodynamic changes induced by centrally administered ADM [13-52], the effect of centrally administered ADM[13-52] on renal sympathetic nerve activity (RSNA) was studied. The result showed that centrally administered ADM [13-52] (1.6 nmol/kg) provoked a marked increase in RSNA, therefore, the increases in MABP and HR induced by centrally administered ADM [13-52] might be due to the stimulation of central sympathetic mechanism. In addition, we also compared the relationship of activity and structure among the different fragments of ADM. In conclusion, ADM exists in the rat brain, and it may play an important role in the central control of cardiovascular system.