[A light and scanning electron microscopic study of primary teeth in hypophosphatasia]

OBJECTIVE

To investigate the features of primary tooth structure in hypophosphatasia.

METHODS

Three primary teeth from two patients at age of 3 yr-6 month and 4 yr-2 month, who were diagnosed hypophosphatasia. The structural changes of these teeth were examined by light microscopy, polarizing microscopy and scanning electron microscopy.

RESULTS

The complete absence of cementum was a prominent feature in all the teeth, three small island-shape cementun areas were found in scanning electron microscopy. A large number of resorptions were found on the root surfaces, particularly near apical portions of roots. The main findings included disturbances of dentin mineralization, hypoplasia or aplasia of root cementum and external resorption of root dentin.

CONCLUSION

The hypoplasia or aplasia of root cementum was thought to be the prime etiological factor in the early loss of primary teeth.

[Expression of c-fos prooncogene in rat brain induced by an olfactory stimulus]

OBJECTIVE

In order to investigate how widespread the activated regions induced by an olfactory stimulus throughout the central nervous system (CNS), c-fos expressions in CNS of the rat observed, which is known as a combined morphologically and functionally probe.

METHODS

Rats were stimulated by iso-amyl acetate for about 10 times, then one hour later sacrificed with perfusion of fixatives. After ABC immunocytochemi cal staining with anti-c-fos polyclonal antiserum, the c-Fos protein labelling areas on sections of the brain were observed.

RESULTS

The results showed that the labelling areas were estremely widespread throughout the brain and cervical segments of the spinal cord in the rat, expecially much more in the areas above the level of the pons. Nearly all neuronal structures in the limbic system were labeled in addition to structures of the olfactory pathways, suggesting there were neuronal activities in multiple neural circuits, which may be associated with emotional, somatic and visceral responses to the olfactory stimulus. Next, many brain areas which were associated with mechanisms of attention and central state regulation were widely labeled. Unexpected heavy labellings in deep layers of the superior colliculus, inferior colliculus and pontine nuclei were presumably relevant to integrating activity between sensations and motions.

CONCLUSIONS

The present study indicated that a specific olfactory stimulus did induce widespread activities of so-called pan-brain networks within the central nervous system.

Human stearoyl-CoA desaturase: alternative transcripts generated from a single gene by usage of tandem polyadenylation sites

A critical step in the synthesis of unsaturated fatty acids is catalysed by stearoyl-CoA desaturase (Scd). To determine the regulation of human Scd, we characterized the gene and its transcripts. Screening a human keratinocyte cDNA library and analysis of 3'-RACE (rapid amplification of cDNA ends) products from various tissues yielded a 5.2 kb cDNA encoding a 359 amino acid protein with a calculated molecular mass of 41.5 kDa. Analysis of 3'-RACE products suggested that alternative usage of polyadenylation sites generates two transcripts of 3.9 and 5.2 kb, a result consistent with Northern analysis. Southern analysis demonstrated the existance of two SCD loci in the human genome. Chromosomal mapping localized one locus to chromosome 10, and the second locus to chromosome 17. Characterization of genomic clones isolated from chromosome-specific libraries revealed that only the locus on chromosome 10 contained introns. Sequence analysis of the intron-less locus displayed multiple nucleotide insertions and deletions, as well as in-frame stop codons. Reverse transcriptase-PCR analysis performed with primers specific to the intron-less locus failed to produce a PCR product from brain, liver and skin RNA, indicating that the locus on chromosome 17 is most likely a transcriptionally inactive, fully processed pseudogene. These results suggest strongly that there is one structural SCD gene in the human genome, and that it generates two transcripts by use of alternative polyadenyation sites. Although the primary sequence and intron-exon structure of SCD is phylogenetically conserved, divergence between rodent and human is seen in the number of SCD genes and in the generation of alternative transcripts, suggesting a species-specific component of SCD regulation and function.

[Study on effect and mechanism of essential garlic oil in inhibiting monocyte-vascular endothelial cell adhesion induced by interleukin-1 alpha]

OBJECTIVE

To observe the effects of essential garlic oil (EGO) on vascular cell adhesive molecule-1 (VCAM-1) expression of endothelial cell and monocyte adhesion induced by interleukin-1 alpha (IL-1 alpha).

METHODS

Human umbilical vein endothelial cells (HUVEC) were isolated by pancreatin digestion method and co-cultured with U937 monocyte and IL-1 alpha or EGO + IL-1 alpha respectively. The adhesion rate of monocyte to endothelial cell was measured and mean fluorescent intensity of immuno-stained of VCAM-1 was determined by ACAS 570.

RESULTS

EGO showed significant inhibition on VCAM-1 expression induced by IL-1 alpha either in simple culture with HUVEC or in co-culture with HUVEC + U937, and could obviously down regulate the monocyte-endothelial cell adhesion under effect of IL-1 alpha.

CONCLUSION

EGO has the effect of antagonizing against adhesion of monocyte and vascular endothelial cell, it may be due to the inhibition of EGO on adhesive molecular expression on endothelial cell.

[Clinical observation of dental pulp and root changes of juvenile anterior permanent teeth after concussion and luxation]

OBJECTIVE

To observe the incidence of pulp necrosis and root resorption of the juvenile anterior permanent teeth with concussion and luxation injuries and analyze the relationship between the type of injury and form of root resorption.

METHODS

157 teeth of 79 patients were chosen from 201 patients with concussion and luxation treated with functional-bite-plate at the Department of Pedodontics, School of Stomatology, Beijing Medical University from 1984 to 1996.

RESULTS

High occurrence of pulp necrosis and root resorption were found in teeth with intrusion, and pulp necrosis occurred most within 3 months after the injury, while root resorption occurred during 3 weeks to 2 years. At the same time, surface resorption occurred mainly in the teeth with intrusion, extrusion and lateral luxation, and replacement resorption occurred only in intrusive teeth, however inflammatory resorption occurred in extrusive teeth whose pulp was infected.

CONCLUSION

Intrusion is the most severe type of tooth trauma.

[Geneotic analysis of wild type measles viruses circulating in China during 1995-1997]

To investigate the molecular epidemiology of measles virus (MV) in China, sequence analysis of MV was performed based on a 282-nt region of the nucleoprotein (N) gene and a 450-nt region of heamaglutinin (H) gene by direct sequencing of RT-PCR amplicons obtained from clinical specimens. Results revealed that one MV strain belonged to ED-like genotype and remainder strains were clustered into a new genotype which was distinct from Chinese vaccine strains and MV strains circulating in other countries, as previously described representing a new genotype. There was up to 15.4% divergence in the nt-282 N gene and 10.8% divergence in the nt-450 H gene between the new genotype and other genotypes.

Characterization of a new genotype of measles virus detected in China and England

We report the co-circulation of a new lineage of measles virus (MV) and an Edmonston-like (Ed-like) genotype of MV in China during 1995-7. Sequence analysis of 25 strains was performed on a 282 nucleotides (nt) region of the nucleoprotein (N) gene, a 450-nt region of the haemagglutinin (H) gene and a 152-nt region of the matrix (M) gene by direct sequencing of RT-PCR amplicons obtained from clinical specimens. The entire H gene was sequenced from two strains. The results showed that 24/25 Chinese strains belonged to a new genogroup and were distinct from the vaccine strains used in China and the UK, and also from MV strains previously described in Europe, Africa and the USA. The remaining strain was Ed-like. Two strains of the new genotype (IV) and one of the Ed-like genotype were also detected in the UK in 1996.

Identification of a new non-major histocompatibility complex genetic locus on chromosome 2 that controls disease severity in collagen-induced arthritis in rats

OBJECTIVE

To identify novel non-major histocompatibility complex (non-MHC) genetic loci controlling the severity of homologous rat type II collagen-induced arthritis (CIA).

METHODS

We conducted a genome-wide scan to identify CIA regulatory quantitative trait loci (QTL) in an F2 cross between DA (CIA highly susceptible) and ACI (CIA resistant) inbred rats immunized with homologous rat type II collagen (RII). These strains share the MHC/RT1av1 haplotype required for susceptibility to RII-induced CIA.

RESULTS

F2 females had higher median arthritis scores than did males. Relative resistance in the males was determined by inheriting either a DA or an ACI Y chromosome and was independent of the source of the X chromosome. In addition, a major QTL was localized on chromosome 2 (Cia7, logarithm of odds score 4.6). Cia7 is in a region that shows linkage conservation with chromosomal regions that regulate autoimmune diabetes and experimental autoimmune encephalomyelitis in mice and multiple sclerosis in humans.

CONCLUSION

Sex chromosomes and Cia7 play an important role in regulating CIA in response to RII. This rat model should facilitate positional cloning and functional characterization of regulatory genes that may play a role in several forms of autoimmune disease, including rheumatoid arthritis.

Determination of absorption characteristics of AG337, a novel thymidylate synthase inhibitor, using a perfused rat intestinal model

The purpose of this study was to determine the intestinal absorption characteristics of AG337, a mechanism-based inhibitor of thymidylate synthase, using a perfused rat intestinal model. Effects of site, pH, temperature, concentration, Na+, and inhibitors on the absorption of AG337 were determined, after the compound was shown to be stable in buffers of various pH, blank perfusate, and intestinal homogenate. The results indicated that absorption of AG337 was temperature-, pH-, Na+-, concentration-, and site-dependent. The best site of absorption is duodenum, where the absorption was 3-10 times (p < 0. 05) higher than absorption at jejunum, ileum, and colon. Among the four pH's studied, the best was at pH 6.5 (p < 0.05). Absorption was 80% lower in the absence of Na+, and 75% lower when the temperature of the perfusate was decreased to 4 degreesC. Permeability of AG337 also decreased about 75% when the concentration was raised to 100 microM. These results suggest that a nutrient carrier may be involved in the transport of AG337. To determine the carrier responsible for the absorption of AG337, its absorption was determined in the presence of various inhibitors at different concentrations. The results indicated that transport of AG337 was inhibited significantly (p < 0.01) by 100 microM of adenine, hypoxanthine, and xanthine. The transport was also inhibited significantly (p < 0.01) by a mixture of 100 microM each of adenine, hypoxanthine, and xanthine, but not by a mixture of 100 microM each of thymine and uracil. A higher concentration of hypoxanthine resulted in increased inhibition. In contrast, prototypical inhibitors of nucleoside transporter, dipyridamole and nitrobenzylthioinosine (NBMPR), did not significantly decrease the transport of AG337. The results also showed that absorption of AG337 had a significant nonsaturable component, with a nonsaturable Pw of 0.8. In conclusion, absorption of AG337 in the rat intestine has been shown to be mainly via a purine base carrier with a significant nonsaturable component.

[Treating portal hypertension by subtotal splenectomy with retroperitoneal splenic transposition and devascularization: clinical study]

OBJECTIVE

To devise a new surgical procedure for improving the operative effect of portal hypertension caused by hepatic cirrhosis.

METHOD

In treatment group, subtotal splenectomy with retroperitoneal transposition was performed in 36 patients of cirrhotic hypertensives. In control group, 36 patients were treated by devascularization. The follow-up period ranged from 3 months to 5.5 years (average 26 months).

RESULT

In the treatment group, the rates of disappearance, improvement and absence of changes of esophageal varices were 11.5%, 61.5% and 26.9%, respectively, and in the control group those of improvement were 50.0%, absence of change 45.8% and aggravation 4.2%. There was a significant difference between them (P < 0.05). In the treatment group, hypersplenism disappeared in all. There was also significant difference between the two groups in immunological indexes (P < 0.05). DSA showed abundant collateral circulation in the residual spleen and retroperitoneal wall, which enabled the portal blood flow diverting to retroperitoneal tissues.

CONCLUSION

This method possesses the advantages of devascularization and decompression shunt. It is of value in retaining part of spleen in surgical treatment of portal hypertension.

[Effects of carbon disulfide on neurotransmitter and its metabolites in rats]

OBJECTIVE

In order to study the mechanism of neurotoxic effects of carbon disulfide (CS2) on animal behavior.

METHODS

Changes in monoamine transmitter, amino acid transmitter and their metabolites in brain tissues were observed in rats exposed to CS2 at levels of 0, 1,200 and 2,400 mg/m3 respectively, for two months, with high performance liquid chromatography.

RESULTS

Indicated that exposure to CS2 could cause decrease in 3-methoxy-4-hydroxy mandelic acid (VMA), increase in 3,4-dioxybenzoic acid, a metabolite of dopamine, and high vanillic acid in rat straitum, decrease in excitatory amino acids and their metabolites (glutamine, aspartic acid and asparagine), with a certain relationship between contents of VMA, aspartic acid and asparagine and changes in neurobehavior.

CONCLUSION

Disturbance of neurotransmitter metabolism plays an important role in neurotoxic effects of CS2.

[Comparison of defibrase and heparin in the prevention of thrombosis after coronary intervention]

To evaluate the effects of defibrase on thrombosis after coronary intervention. 12 dogs were randomized into group to be treated with defibrase (n = 6) and another group with heparin (n = 6) after coronary intervention. After implanting stents in coronary arteries, canine platelets labeled with 99mTc-hexamethyl propylene amine oxime were re-transfused into blood circulation. The stenting vessels were imaged with gamma-camera in vivo and in vitro at the 4th and 24th hour, then the relative radioactivity of stenting vessels was quantified. The isolated stenting vessels were weighted and measured with gamma-counter and the number of deposited platelets was calculated. The relative radioactivity and the number of deposited platelets were lower in the group of defibrase than in the group of heparin (P < 0.01). Compared with heparin, defibrase has more potent effect on the prevention of thrombus formation and may reduce the early-reocclusion after coronary intervention.

Risk factors for human cysticercosis morbidity: a population-based case-control study

A population-based case-control study to determine social and behavioural risk factors for Taenia solium cysticercosis in humans was carried out in a rural area. Shandong province, China. Forty-eight cases with cysticercosis were ascertained through a prevalence survey conducted among 7281 persons in 1993. For each case, four controls residing in the same village and matched for age and sex were randomly selected. Information regarding demographic, social and behavioural factors was collected during house visits through interviews and direct observation. Risk factors strongly associated with human cysticercosis included poor personal hygiene, being unable to recognize cysticerci-containing meat, poor pig-raising practices and a history of passing tapeworm proglottides. The results indicate that health education in combination with chemotherapy for taeniasis is required for the control of cysticercosis in humans.

[Effect of intestinal lymph on blood pressure of rat]

The effect of intestinal lymph on blood pressure in rats was observed by the methods of lymph drainage and lymph infusion. The results obtained are as follows: (1) After 150 min of the lymph drained through the cannula of intestinal lymph duct, the blood pressure was significantly lower than that of the sham group (P < 0.05). (2) Equivalent albumin or intralipid infusion was not able to prevent the decrease in blood pressure when the lymph was lost. But in jugular-intestinal lymph duct shunt group, no significant blood pressure decrease could be seen during the drainage procedure for 4 h. (3) The blood pressure of rat with serious hemorrhagic shock could be increased significantly with a little amount of intestinal lymph infusion, and the rats survived longer than those of the control group (P < 0.05-0.01). The above results suggest that the intestinal lymph may play an important role in maintenance of blood pressure, in addition to the known function of lymphatic system by returning tissue fluid to blood and maintaining circulating blood volume.

Selectively-infective phage (SIP): a mechanistic dissection of a novel in vivo selection for protein-ligand interactions

Selectively-infective phage (SIP) is a novel methodology for the in vivo selection of interacting protein-ligand pairs. It consists of two components, (1) a phage particle made non-infective by replacing its N-terminal domains of geneIII protein (gIIIp) with a ligand-binding protein, and (2) an "adapter" molecule in which the ligand is linked to those N-terminal domains of gIIIp which are missing from the phage particle. Infectivity is restored when the displayed protein binds to the ligand and thereby attaches the missing N-terminal domains of gIIIp to the phage particle. Phage propagation is thus strictly dependent on the protein-ligand interaction. We have shown that the insertion of beta-lactamase into different positions of gIIIp, mimicking the insertion of a protein-ligand pair, led to highly infective phage particles. Any phages lacking the first N-terminal domain were not infective at all. In contrast, those lacking only the second N-terminal domain showed low infectivity irrespective of the presence or absence of the F-pilus on the recipient cell, which could be enhanced by addition of calcium. An anti-fluorescein scFv antibody and its antigen fluorescein were examined as a protein-ligand model system for SIP experiments. Adapter molecules, synthesized by chemical coupling of fluorescein to the purified N-terminal domains, were mixed with non-infective anti-fluorescein scFv-displaying phages. Infection events were strictly dependent on fluorescein being coupled to the N-terminal domains and showed a strong dependence on the adapter concentration. Up to 10(6) antigen-specific events could be obtained from 10(10) input phages, compared to only one antigen-independent event. Since no separation of binders and non-binders is necessary, SIP is promising as a rapid procedure to select for high affinity interactions.

Localization of the gene responsible for the op (osteopetrotic) defect in rats on chromosome 10

Osteopetrosis, a skeletal disorder of inadequate bone resorption with an abnormal increase in skeletal mass, results from a variety of independent single gene mutations that affect osteoclast differentiation and/or function. The osteopetrotic defect, op, is one of four spontaneous, nonallelic mutations in rats that result in osteopetrosis. In intercross progeny of (BN/SsN x LEW/SsN. +/op) F1 carriers, we mapped this locus by linkage analysis with microsatellite markers to rat chromosome 10. The linkage group contained, as well as op, 15 anonymous DNA loci and 9 DNA loci associated with genes (interleukin-3, myosin heavy chain [skeletal, embryonic], asialoglycoprotein receptor [hepatic lectin]-1, vesicle-associated membrane protein [synaptobrevin-2], sex hormone binding globulin, aldolase C, nitric oxide synthase [inducible], erythroblastic leukemia avian viral oncogene homolog-2, and proline-rich protein). The markers for these loci include nine not previously reported. The op locus mapped to the end of the chromosome 10 linkage group, within 1 cM of the anonymous DNA locus, D10Mit6. Based on its location, the op gene is likely to be distinct from seven described mutations in mice as well as three other mutations in rats. These results may permit a positional cloning strategy to be undertaken to identify the gene and mutation underlying the op defect.

Prime factors

We use Voiculescu's free probability theory to prove the existence of prime factors, hence answering a longstanding problem in the theory of von Neumann algebras.