[The antibacterial efficacy to obligate anaerobes isolated from the infected root canal of deciduous teeth]

TMJ osteoarthrosis(OA) is frequently seen in the Oral and Maxillofacial Surgery clinics.In order to investigate cellular and molecular basis of the pathogenesis of TMJOA,the levels of IL-1 and IL-6 in synovial aspirates from different stages of TMJOA patients were determined and analysed.It was found that both of them were highly correlated with the severity of TMJOA(P<0.0001).A positive linear correlation was also found between IL-1 and IL-6(P<0.0001).The balance and imbalance between MMPs and TIMPS and the modulatory mechanism of cytokines were introduced and their possible roles in the pathogenesis of TMJOA were discussed.

Occipital encephalocele and MURCS association: case report and review of central nervous system anomalies in MURCS patients

The combination of MURCS association (Müllerian duct and renal agenesis, upper limb and rib anomalies) and occipital encephalocele occurred in a stillborn girl of 41 weeks gestation. The malformations are compatible with a defect in the organization of the paraxial mesoderm that gives rise to occipital, cervical, and thoracic somites and adjoining intermediate mesoderm. These structures contribute to the occipital bone, cervical spine, upper limbs, and urogenital system. Brain imaging may be useful in assessing MURCS patients, if cranial malformations prove to be clinically important in these individuals.

[Multifactor analysis of predisposing factors of oral candidosis in adults]

To study the prodisposing factors of oral candidosis in adult, analyst statistic package (quantity theories II) were used for the multifactor regressive analysis on 116 cases with oral candidosis and 76 gender and age matched normal controls. Six possible predisposing factors including gender, smoke, job, denture, drug use, systemic and other mucosal disease accompanied were inquired. The results showed that the most active predisposing factors were systemic or other oral mucosa disease accompanied, which include post-operative states, post-radiotherapy states, Sjogren's syndrome; followed by drug use before onset of oral candidosis, especially topic antibiotics; the four other factors (smoke, job, denture and gender) have some effect but do not play any conclusive role on the occurence of oral candidosis.

Coding sequence and chromosome mapping of the human gene (CDC46) for replication protein hCdc46/Mcm5

We have isolated the complete cDNA sequence encoding the human homolog of the yeast replication protein Cdc46/Mcm5. The cDNA was used as a probe for chromosomal fluorescence in situ hybridization (FISH), which localized the human Cdc46 gene (CDC46) to chromosome region 22q13.1-->q13.2. This is the fourth human Mcm gene whose chromosome region has been determined, and it is now apparent that human Mcm genes are widely distributed in the genome. As deduced from the cDNA sequence, human protein hCdc46 is composed of 734 amino acids and contains a central region that is almost 80% identical with the yeast protein. Immunoprecipitation experiments with hCdc46-specific antibodies confirm that essentially all nuclear hCdc46 proteins form a stable dimeric complex with protein P1Mcm3.

Translational enhancement of FGF-2 by eIF-4 factors, and alternate utilization of CUG and AUG codons for translation initiation

The FGF-2 mRNA of most mammals contains a long and inhibitory 5' UTR in addition to at least two CUG codons upstream and in frame with the AUG start codon. These CUGs are used for translation initiation to generate several polypeptides. Cells overexpressing the translation initiation factor 4E produce and secrete large amounts of FGF-2, and particularly the largest, CUG1-initiated form. Overexpression of FGF-2 is due to a translational enhancement of its mRNA, as indicated by its association with large polyribosomes in contrast to control cells, where it partitions mostly in fractions lighter than 80 S or small polyribosomes. Breast carcinomas expressing elevated eIF-4E also exhibited the large FGF-2 isoforms, which could play an important role in tumor angiogenesis. Translation of in vitro transcribed rat FGF-2 in reticulocyte lysates resulted in synthesis of four polypeptides, of similar size to those observed in vivo. Addition of purified eIF-4F preferentially increased translation of CUG1- and AUG-initiated isoforms. Since the different isoforms of FGF-2 may have different roles and intracellular distribution, the effects of the eIF-4 factors on FGF-2 expression could be important for the control of cell proliferation and differentiation.

Muscarine induces an anomalous inhibition of synaptic transmission in rat auditory thalamic neurons in vitro

Muscarinic receptor-mediated inhibition of central synaptic transmission was studied in a monosynaptic pathway connecting the inferior colliculus and the auditory thalamus in in vitro rat brain explants. Extra- and intracellular synaptic responses were recorded by sharp electrode and whole-cell patch clamp techniques in the ventral nucleus of the medial geniculate body after electrical stimulation of the brachium of the inferior colliculus. Stimulation of tectal afferents evoked either a high-frequency burst or a single-spike synaptic response in ventral geniculate neurons. Bath application of muscarinic receptor agonists abolished responses consisting of a high-frequency burst, but not responses consisting of a single spike. In the majority of single-spike cells muscarinic agonists often induced a synaptic facilitation. The burst blocking effect was mimicked by a moderate elevation of extracellular potassium. Intracellular recordings showed that the burst synaptic responses similar to that recorded extracellularly were induced by an excitatory postsynaptic potential. This synaptic potential, by first activating a low-threshold spike, was able to evoke a burst of sodium spike discharges. Muscarinic agonists caused a slow membrane depolarization that inactivated the low-threshold spike, leading to a blockade of the burst response. This mechanism is tentatively termed here as EPSP-LTS decoupling. Our results therefore support the hypothesis that part of the muscarinic receptor-mediated synaptic inhibition previously reported in anesthetized animal preparations in vivo represents a membrane depolarization rather than pre- or postsynaptic inhibition.

[Experimental study on transplantation inside and outside tendon sheath]

The range of motion of PIP and morphological changes of tendon grafts were studied after inside outside tendon sheath grafting in rabbits. It was found that the inside tendon sheath grafting together with early postoperative mobilization healed without adhesion, and most of the cells remained viable. After outside tendon sheath grafting, the tendon cells proliferated with extensive adhesions. The range of PIP motion was greater after inside tendon sheath grafting than that after outside tendon sheath grafting. The results suggest that tendon grafting is donor-tissue-specific and the synovial layer of inside tendon sheath plays an important role in preventing adhesion formation.

Experimental studies of the effect of Forskolin on the lowering of intraocular pressure

PURPOSE

To determine the effect of domestic Forskolin on lowering of intraocular pressure (IOP) in rabbits.

METHODS

Measure the normal IOP and ocular hypertension by water load in rabbits using Perkins tonometer. Measure the adenylate cyclase (AC) activity by Ho & Sutherland's method.

RESULTS

The results show that Forskolin significantly lowered the normal IOP of rabbits and blocked the ocular hypertension induced by water load in rabbits (P < 0.01). The maximum decrease value of 2%, 1% and 0.5% of the Forskolin was 0.59, 0.36 and 0.19 kPa (1kPa = 7.5 mmHg), which showed the noticeable dose-effect relationship. Topical ocular application of Forskolin lowered IOP in half an hour, reached to a peak in 2-3 hours and remained significantly for 10 hours. The pupillary diameter did not change when IOP was reduced. The Forskolin had potent stimulative properties to AC. The greater the ability of the Forskolin to stimulate AC, the stronger the effect of IOP lowering.

CONCLUSIONS

The Forskolin had the effect on lowering the IOP of rabbits. The mechanism of IOP reduction by Forskolin is related to its AC activation.

Adenovirus mediated gene transfer of vascular smooth muscle cells and endothelial cells in vitro

Introducing foreign gene(s) into vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) is the pre-requirement of gene therapy for cardiovascular diseases. We have explored the use of adenoviral vectors (Adv-CMV/LacZ) to transfer LacZ gene into cultured VSMCs and ECs. Our results demonstrated that adenoviral vectors transferred foreign gene into VSMCs and ECs high-efficiently with dose-dependent response pattern. The frequencies of transfection reached 100% at the viral titer of 10(9) pfu/ml. Comparing the sensitivities of VSMCs and ECs to adenoviral vectors, we found that ECs were more sensitive than VSMCs, of which the frequencies of transfection in ECs reached 80% while in VSMCs only 40% for 8 hrs after transfection. In addition, the transfection of ECs and VSMCs with adenoviral vectors was partly blocked by monoclonal antibodies to Fiber and Core protein of the adenoviral capsid, but not by monoclonal antibody to Hexon protein. It is suggested transfection of ECs and VSMCs with adenovirus vectors is mediated by Fiber or Core protein of adenoviral capsid proteins.

Interleukin-1 enhances indoleamine 2,3-dioxygenase activity by increasing specific mRNA expression in human mononuclear phagocytes

The objective of this study was to determine the utility of the THP-1 monocytic leukemia cell line as a model for analyzing molecular mechanisms involved in enhancement of interferon (IFN)-gamma-induced indoleamine dioxygenase (IDO) activity by interleukin-1 (IL-1). Following treatment of THP-1 cells with combinations of IFN-gamma and IL-1, IDO activity and IDO mRNA were quantified by HPLC and radioanalytic imaging of RT-PCR products, respectively. IL-1 increased the amount of IDO activity and the expression of IDO mRNA in IFN-treated cells; IL-1 alone had no effect on untreated THP-1 cells. Because IDO gene regulation might differ between immature THP-1 cells and mature macrophages, experiments were repeated using primary macrophage cultures. IFN-gamma induced IDO activity, and IDO mRNA was expressed in a dose-dependent manner. In the presence of IL-1, 10 times less IFN was required to obtain the same amount of IDO mRNA and IDO activity. Furthermore, IL-1 alone increased IDO mRNA expression. It appears that unlike what was observed in THP-1 cells, IL-1 transcriptionally activates the IDO gene in primary macrophages. However, increases in IDO activity were not observed following treatment with IL-1 alone. Although the THP-1 cell may be used to model cytokine potentiation of IFN-induced IDO activity, some differences in regulation between THP-1 cells and primary macrophage cultures may exist.

A molecular model of low-voltage-activated calcium conductance

1. T-type or low-voltage-activated Ca2+ channels (IT) expressed in the mammalian thalamus play an important physiological role in the induction of membrane potential oscillations and in the regulation of the timing of synaptic signaling. On the basis of recent molecular studies on Ca2+, Na+, and K+ channels, a structure-kinetic model has been proposed for IT. 2. The model considers that the pore-opening process of IT is governed by three of the four protein domains that are arranged asymmetrically across the membrane plane. The three cytoplasmic linkers connecting individual channel domains serve as inactivation gates. On a membrane voltage change, each domain may engage independently into a sequential, thermodynamically coupled conformational change, thereby causing channel activation and inactivation. 3. A linear Marcov chain reaction with coupled channel activation and inactivation was adopted to test the kinetic feasibility of this trimeric model in a single-compartmental thalamic cell. The differential equations for voltage-dependent rate constants and transitional rates were solved to produce macroscopic T-type Ca2+ current. 4. Our simulation results indicate that this novel structure-kinetic model produces excellent predictions of the macroscopic behaviors of IT, and, more importantly, it provides some new insights into the microscopic mechanism underlying channel recovery.

Changes in the endocochlear potential and cochlear blood flow induced by ATP infusion and arterial occlusion

To assess the relationship between cochlear blood flow (CBF) and auditory function, a procedure of intravital microscopy for observations of the lateral wall vessels of the cochlea coupled with the simultaneous measurement of the endocochlear potential (EP) was established in guinea pigs with gradual ischemia of the cochlea. It was found that occlusions of both common carotid arteries and one of the vertebral arteries produced a minor reduction in CBF with no significant alteration in the EP. When intravenous infusion of ATP induced sharp and severe decreases in CBF, the EP varied only slightly from the baseline in some animals while there were no alteration in others. Furthermore, ATP infusions combined with arterial occlusions caused even more severe declines in CBF and a moderate decrease in the EP. The results indicate that not only does the CBF satisfy the basic needs of the processes of cochlear function, but also has a regulatory mechanism to ensure the normal function of the cochlea in the ischemia condition. It was also found that the changes in the stria vascularis vessels induced by decreases in blood pressure (BP) and heart rates were more severe than those of the spiral ligament vessels. This phenomenon indicated that the stria vascularis vessels were more sensitive to decreases of BP and heart rates.

Enhanced adeno-associated virus vector expression by adenovirus protein-cationic liposome complex. A novel and high efficient way to introduce foreign DNA into endothelial cells

Adeno-associated virus vector (AAV), a non-pathogenic integrating vector, can integrate on chromosome 19 in humans. But its gene transfer efficiency is quite low. In this study we combined adenovirus (Adv-5) capsid protein or the Fiber protein of Adv with liposome, termed adenosome (adenovirus protein-cationic liposome complex). This complex can bring AAV/CMV-LacZ to the endothelial cells, and improve the efficiency of gene transfer. It may be a novel, specific, stable and safe gene delivery system and will be widely used in human gene therapy.

Expression of cholecystokinin mRNA in corticothalamic projecting neurons: a combined fluorescence in situ hybridization and retrograde tracing study in the ventrolateral thalamus of the rat

Cholecystokinin (CCK), a well-known neuroactive peptide, has been observed in the axon endings within the thalamic reticular nucleus and the adjacent ventrolateral nucleus of the thalamus. The origin of this CCK innervation remains undefined. In this study, a fluorescence in situ hybridization (FISH) technique was used in conjunction with latex microsphere retrograde tracing to investigate whether cortical neurons may provide a source of CCK afferents to the ventrolateral thalamic nucleus. Rhodamine latex beads were injected into the ventrolateral thalamic nucleus of adult male rats to retrogradely label corticothalamic cells. After 7 days, tissues were processed for FISH using a 24-base oligonucleotide probe complementary to the 3' coding region of rat preprocholecystokinin mRNA. It was found that CCK transcripts are expressed in about 80% of identified corticothalamic projecting neurons. We therefore conclude that the descending cortical projections to the ventrolateral thalamus may provide an important source of CCK innervation to this region of the brain.

Regulation of spontaneous phasic firing of rat supraoptic vasopressin neurones in vivo by glutamate receptors

1. Vasopressin-secreting neurones in the rat hypothalamic supraoptic nucleus display patterned spontaneous phasic activity, which is apparently maintained in vivo through yet unidentified neurotransmitter system(s). The present investigation used extracellular recording techniques in anaesthetized Long-Evans rats to evaluate whether the neurotransmitter mechanism underlying phasic firing is provided via a family of ionotropic glutamate receptors. 2. N-Methyl-D-aspartate (NMDA) reliably evoked bursts of activity in twenty-seven of twenty-eight phasic neurones. Amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA) and kainate also elicited pronounced excitations in twenty-one of twenty-one and and fourteen of fifteen phasic cells, respectively. 3. A rapid blockade of on-going phasic activity was consistently induced following brief applications of both NMDA and non-NMDA receptor antagonists; extended application of antagonists resulted in prolonged silent periods, during which phasic activity failed to recur for minutes. Neither saline nor a cholecystokinin receptor antagonist influenced cell firing. 4. In contrast to putative vasopressin cells, application of NMDA receptor ligands did not affect the spontaneous activity in most putative oxytocin-secreting neurones, whereas kainate and AMPA potently excited seven of nine and four of five putative oxytocin cells, respectively. 5. These results imply that the maintenance of spontaneous phasic discharges in vivo in supraoptic vasopressin-secreting neurones requires tonic synaptic activation involving both NMDA and non-NMDA glutamate receptors. In putative oxytocin-secreting neurones, spontaneous firing appears to be predominantly regulated by non-NMDA receptors. Glutamatergic innervations may be in a unique position to influence the genesis of patterned electrical activity in supraoptic vasopressin neurones.

Expression, phosphorylation and nuclear localization of the human P1 protein, a homologue of the yeast Mcm 3 replication protein

The human protein P1 belongs to a newly discovered class of mammalian nuclear proteins with high sequence homology to yeast replication proteins. We present the entire amino acid sequence of the human protein P1 as predicted from the cDNA sequence, and show that P1 shares three central regions of high sequence similarity (about 75%) and a highly hydrophilic carboxy-terminal region with the yeast Mcm3 replication protein. The human genome most probably contains one P1 gene which is activated when HeLa cells progress to S phase, as shown by a several-fold increase in P1-specific mRNA. However, the amounts of P1 protein do not detectably change during this period, but P1 protein becomes phosphorylated at the beginning of S phase. In contrast to the yeast Mcm proteins, which disappear from nuclei after initiation of DNA replication, protein P1 remains in the nucleus during and after S phase. P1 is dispersed in mitotic cells and may be excluded from binding to chromosomes.

The analysis of disparity evoked potentials by a new form of static random-dot stereograms

PURPOSE

A new form of static random-dot stereograms free of monocular clues was designed as stimulus to elicit disparity evoked potentials.

METHODS

Disparity evoked potentials were recorded in 40 stereo-normal subjects. The stimulator was a white-black static random-dot stereograms generated by a computer and had no monocular clues. Every subject was tested in disparity stimulus, zero disparity stimulus, monocular stimulus and wearing prism condition.

RESULTS

A characteristic wide positive wave at about 250 ms was consistently recorded in disparity stimulus, which may be regarded as evidence of the presence of stereopsis. In contrast, recordings for zero disparity stimulus, monocular vision, stimulus and wearing prism condition all demonstrated a markedly difference from recording for disparity stimulus.

The proto-oncogene/translation factor eIF4E: a survey of its expression in breast carcinomas

The eukaryotic translation initiation factor eIF-4E binds to the cap structure of mRNAs as one component of the eIF-4 translation initiation complex, which mediates the recruitment of mRNA to the ribosomes. Overexpression of eIF-4E can result in oncogenic transformation and uncontrolled growth of mammalian cells, presumably by facilitating the expression of growth-control gene products which are normally translationally repressed. Whereas the mechanism of eIF-4E-mediated transformation is being actively pursued, clinical investigations into the expression of eIF-4E in prevalent human cancers are lacking. We have recently initiated a screen of breast carcinomas by probing with eIF-4E antiserum. Using Western blots, we have analyzed the level of eIF-4E in 38 carcinomas, 7 normal samples and 3 fibroadenomas. We found that eIF-4E was elevated 3- to 10-fold in virtually all the carcinomas we analyzed, but not in fibroadenomas. This analysis was also confirmed by immunohistological staining in situ, showing that overexpression of eIF-4E can be readily identified at the single-cell level. Our results suggest that an elevation of eIF-4E may be an essential component in the development of breast cancer.

Cellular basis of temporal synaptic signalling: an in vitro electrophysiological study in rat auditory thalamus

1. The cellular mechanisms underlying temporal synaptic signalling of tectothalamic pathways were investigated in rat medial geniculate body (MGB) maintained in vitro. Stimulation of the brachium of the inferior colliculus elicited either a short latency, single- (or dual-) spike or a long latency (10-80 ms) burst in MGB neurones. The delayed burst response was found in most non-lemniscal or caudodorsal MGB (MGd) neurones, whereas single-spike units were mainly seen in the lemniscal ventral MGB (MGv). Population latency analysis revealed that the overall relay time of tectothalamic transmission is approximately 50 ms, with at least two excitation peaks occurring around 8 and 15 ms, respectively. 2. Intracellular recordings showed that the delayed burst responses in MGd neurones were mediated by an EPSP-triggered low threshold spike (LTS). Small variations in either the membrane voltage or in EPSP amplitude induced significant shifts of LTS latency. 3. Compared with MGv cells, MGd neurones exhibited a more negative resting membrane potential and a prolonged EPSP; they lacked an apparent hyperpolarization-activated inward rectifier (Ih). These factors seem to lead collectively to a dominant occurrence of long latency burst response in the MGd. In the majority of single-spiking MGv cells that expressed a clear Ih, application of Cs+ consistently hyperpolarized the cell, which transformed a single-spike synaptic response into an EPSP-LTS burst or a subthreshold EPSP. 4. Taken together, these data suggest that the monosynaptic tectothalamic pathways are capable of introducing a ventrodorsal gradient in auditory response time. This synaptic activity pattern is probably dominantly regulated by a set of membrane conductances expressed endogenously in thalamocortical neurones.

Isolation and molecular cloning of a novel bone phosphoprotein related in sequence to the cystatin family of thiol protease inhibitors

We describe here the isolation of a novel non-collagenous protein from the acid demineralization extract of bovine cortical bone. This 24-kDa protein is multiply phosphorylated at serine residues in Ser-X-Glu/Ser(P) sequences, a recognition motif for phosphorylation by the secretory pathway protein kinase, and we have termed this protein secreted phosphoprotein 24 (spp24). The cDNA structure of spp24 was determined by sequencing cDNA fragments obtained by reverse transcription-polymerase chain reaction, 3'-rapid amplification of cDNA ends, and screening a lambda gt11 cDNA library. This cDNA sequence predicts a 200-residue initial translation product which consists of a 20-residue signal sequence and the 180-residue mature spp24. Northern blot analysis using the spp24 cDNA showed that spp24 mRNA is in liver and bone but not in heart, lung, kidney, or spleen. A search of existing protein sequences revealed that the N-terminal 107 residues of mature spp24 are related in sequence to the cystatin family of thiol protease inhibitors, which suggests that spp24 could function to modulate the thiol protease activities that are known to be involved in bone turnover. Several of the proteins in the cystatin family that are most closely related to spp24 are not only thiol protease inhibitors but are also precursors to peptides with potent biological activity, peptides such as bradykinin and the neutrophil antibiotic peptides. It is therefore possible that the intact form of spp24 found in bone could also be a precursor to a biologically active peptide, a peptide which could coordinate an aspect of bone turnover.

Lemniscal and non-lemniscal synaptic transmission in rat auditory thalamus

1. The central auditory pathway linking the inferior colliculus (IC) and the medial geniculate body (MGB) of the thalamus consists of a segregated ventral lemniscal and dorsal non-lemniscal projection whose synaptic transmission mechanisms remain unknown. Extracellular and intracellular recordings combined with axonal tract tracing and cell staining were made from lemniscal and non-lemniscal divisions of adult rat MGB maintained acutely in in vitro explants containing parallel tectothalamic projections. 2. Biocytin deposition within the brachium of the IC revealed dense axonal fibres projecting to the MGB. Thin axonal terminals were found throughout the ventral (MGv) and dorsal (MGd) divisions of the MGB. Bushy cells with tufted or bitufted dendritic branches were primarily found in the MGv. In the MGd, cells were mainly seen as stellate neurones having a radiate dendritic arbor. 3. Electrical stimulation of the brachium of IC invariably elicits fast, excitatory synaptic potentials in both MGv and MGd cells. The evoked responses occurred monosynaptically and were exclusively mediated by glutamate acting on both N-methyl-D-aspartate (NMDA) and non-NMDA receptors. Non-lemniscal MGd neurones recorded extracellularly exhibited a strong tendency to discharge in bursts in response to brachium stimulation. In contrast, a large proportion of ventral lemniscal cells tended to discharge in single or dual spikes. Intracellularly, MGd cells, but not MGv cells, showed a predominant, slow synaptic potential mediated by NMDA receptors. 4. It is concluded that the central auditory circuitry linking the tectum and the thalamus is connected monosynaptically via glutamatergic synapses. Lemniscal and non-lemniscal thalamic neurones possess distinct response properties which cannot be accounted for by a differential transmitter system or polysynaptic delays as postulated previously.