[The role of mtDNA deletion in the sensitivity to aminoglycoside antibiotic induced deafness]

OBJECTIVE

To establish an animal model of mitochondrial DNA (mtDNA) deletion and investigate the possible role of mtDNA deletion in aminoglycoside antibiotic induced deafness.

METHODS

Thirty wistar rats (4 months) were randomly divided into group A and B. Doxorubicin (DOX) was subcutaneously injected at doses of 2 mg/kg twice per week for 3 months in group A and then kanamycin (KM) was intraperitoneally injected 500 mg/kg per day for 10 consecutive days. The treatments of group B were identical to group A, except normal saline was substituted for DOX. The thresholds of auditory brainstem response (ABR) were measured before and after the drug administrations. The inner ear membranous labyrinthine tissue was harvested and mtDNA was amplified to identify 4,834 bp deletion by PCR technique.

RESULTS

The elevation of the mean ABR thresholds in group A(67.08 +/- 8.59) dB peSPL was significantly higher than that in group B (12.71 +/- 4.42) dB peSPL after KM administration (P < 0.001). In group A, 9 of the 15 rats demonstrated 4,834 bp mtDNA deletion. However, mtDNA 4,834 bp deletion was negative in group B animals.

CONCLUSION

DOX can induce mtDNA deletion in the inner ear tissue of the rat. mtDNA deletion in the inner ear may play an important role in the hypersensitivity to aminoglycoside antibiotic ototoxicity.

p53 inhibition by the LANA protein of KSHV protects against cell death

Kaposi's sarcoma-associated herpesvirus (KSHV), or human herpesvirus 8, has been implicated in the development of Kaposi's sarcoma (KS) and several B-cell lymphoproliferative diseases. Most cells in lesions derived from these malignancies are latently infected, and different viral gene products have been identified in association with lytic or latent infection by KSHV. The latency-associated nuclear antigen (LANA), encoded by open reading frame 73 of the KSHV genome, is a highly immunogenic protein that is expressed predominantly during viral latency, in most KS spindle cells and in cell lines established from body-cavity-based lymphomas. Antibodies to LANA can be detected in a high percentage of HIV-infected individuals who subsequently develop KS, although its role in disease pathogenesis is not completely understood. p53 is a potent transcriptional regulator of cell growth whose induction leads either to cell-cycle arrest or apoptosis. Loss of p53 function correlates with cell transformation and oncogenesis, and several viral oncoproteins interact with p53 and modulate its biological activity. Here we show that LANA interacts with the tumour suppressor protein p53 and represses its transcriptional activity. This viral gene product further inhibits the ability of p53 to induce cell death. We propose that LANA contributes to viral persistence and oncogenesis in KS through its ability to promote cell survival by altering p53 function.

Basolateral proteinase-activated receptor (PAR-2) induces chloride secretion in M-1 mouse renal cortical collecting duct cells

1. Using RT-PCR, Northern blot analysis, and immunocytochemistry, we confirmed renal expression of proteinase-activated receptor (PAR-2) and demonstrated its presence in native renal epithelial and in cultured M-1 mouse cortical collecting duct (CCD) cells. 2. We investigated the effects of a PAR-2 activating peptide (AP), corresponding to the tethered ligand that is exposed upon trypsin cleavage, and of trypsin on M-1 cells using patch-clamp, intracellular calcium (fura-2) and transepithelial short-circuit current (ISC) measurements. 3. In single M-1 cells, addition of AP elicited a concentration-dependent transient increase in the whole-cell conductance. Removal of extracellular Na+ had no effect while removal of Cl- prevented the stimulation of outward currents. The intracellular calcium concentration increased significantly upon application of AP while a Ca2+-free pipette solution completely abolished the electrical response to AP. 4. In confluent monolayers of M-1 cells, apical application of AP had no effect on ISC whereas subsequent basolateral application elicited a transient increase in ISC. This increase was not due to a stimulation of electrogenic Na+ absorption since the response was preserved in the presence of amiloride. 5. The ISC response to AP was reduced in the presence of the Cl- channel blocker diphenylamine-2-carboxylic acid on the apical side and abolished in the absence of extracellular Cl-. 6. Trypsin elicited similar responses to those to AP while application of a peptide (RP) with the reverse amino acid sequence of AP had no effect on whole-cell currents or ISC. 7. In conclusion, our data suggest that AP or trypsin stimulates Cl- secretion by Ca2+-activated Cl- channels in M-1 CCD cells by activating basolateral PAR-2.

Stenting of an unprotected left main coronary artery stenosis in a cardiac transplant patient

Cardiac allograft vasculopathy is the leading cause of death in cardiac transplant patients who survive the first year. Retransplantation is limited by shortage of donors and reduced survival rates compared with the initial transplant. Recent reports of successful stenting in these patients may offer some hope, although randomized trials are lacking. Successful stenting of an 'unprotected' left main coronary artery stenosis under cardiopulmonary support is presented in a cardiac transplant patient. A 16-month follow-up angiogram demonstrated a patent stent without restenosis and no interim clinical events.

Proteinase-activated receptor-2 in human skin: tissue distribution and activation of keratinocytes by mast cell tryptase

Proteinase-activated receptor-2 (PAR-2) is a G-protein coupled receptor. Tryptic proteases cleave PAR-2 exposing a tethered ligand (SLIGKV), which binds and activates the receptor. Although PAR-2 is highly expressed by cultured keratinocytes and is an inflammatory mediator, its precise localization in the normal and inflamed human skin is unknown, and the proteases that activate PAR-2 in the skin have not been identified. We localized PAR-2 in human skin by immunohistochemistry, examined PAR-2 expression by RT-PCR and RNA blotting, and investigated PAR-2 activation by mast cell tryptase. PAR-2 was localized to keratinocytes, especially in the granular layer, to endothelial cells, hair follicles, myoepithelial cells of sweat glands, and dermal dendritic-like cells. PAR-2 was also highly expressed in keratinocytes and endothelial cells of inflamed skin. PAR-2 mRNA was detected in normal human skin by RT-PCR, and in cultured human keratinocytes and dermal microvascular endothelial cells by Northern hybridization. Trypsin, tryptase and a peptide corresponding to the tethered ligand (SLIGKVNH2) increased [Ca2+]i in keratinocytes, measured using Fura-2/AM. Although tryptase-containing mast cells were sparsely scattered in the normal dermis, they were numerous in the dermis in atopic dermatitis, and in the dermis, dermal-epidermal border, and occasionally within the lower epidermis in psoriasis. Tryptase may activate PAR-2 on keratinocytes and endothelial cells during inflammation.

[An electrophysiological study of the kainic acid toxicity on cochleas]

OBJECTIVE

The purpose of this study was to investigate the kainic acid (KA) toxicity on cochleas.

METHOD

One microliter KA in the concentration of 60 mM was applied to the round window membrane of guinea pig. The compound action potential (CAP), cochlear microphonic potential (CM) and distortion product otoacoustic emissions (DPOAE) were measured 12 hours after KA was administrated.

RESULT

CAP was suppressed significantly or abolished after the drug administration, however, the CM and DPOAE almost presented no change.

CONCLUSION

The targets of KA toxicity are the primary auditory afferent endings.

[Use PCR technique to detect mitochondrial DNA in rat membranous labyrinth]

OBJECTIVE

To establish a sensitive and reliable method of mtDNA detection in the membranous labyrinth of rat inner ear.

METHOD

A mtDNA segment of 601 bp containing the genes which encode ND1 subunit 16S rRNA in rat inner ear membranous labyrinth was detected by PCR method. The method is compared with Edris's mtDNA isolation method.

RESULT

A 601 bp PCR product of mtDNA in the membranous labyrinth of rat ear inner can be obtained by the two methods. But the requirement of the sample quantities was different for the two methods. The extraction of mtDNA need two of inner ears membranous labyrinth to get reliably result by the method adapted from Seidman. However, the mtDNA extraction procedure from Edris's method need six of inner ears of the in order to get reliably result.

CONCLUSION

The method of mtDNA isolation, amplification and detection membranous labyrinth of rat inner ear by PCR method adapted from seidman is more sersitive.

[Analysis of surgical reconstructions of canal and middle ear via "direct entrance" approach in 53 ears with congenital aural atresia]

OBJECTIVE

To recognize the indication of surgical reconstruction via the "direct entrance" surgical approach (superoanterior surgical approach) for congenital atresia of the external acoustic canal and malformations of the middle ear.

METHODS

A series of 53 ears operated on via the superoanterior surgical approach during 10 years from January 1988 to December 1997 was analyzed.

RESULTS

The tympanic cavity was encountered without difficulty in 52 ears. Facial paralysis occurred postoperatively in one ear, which recovered after two months. The hearing improvement was observed in 45 ears (84.9%), of which 24 ears had hearing improvement greater than 30 dB and the air-bone conduction gap was within 15 dB (45.3%). A long-term (1-9 years) follow-up of 25 ears demonstrated that the hearing levels in 18 ears were kept unchanged. Postoperative stenosis of the canal occurred in one ear of a 2 years-old child.

CONCLUSION

Based on the scanning images of the temporal bone by high-resolution computed tomography before the operation, the authors classified the bony structures of the paths of external acoustic canals into four types. Our results indicated that the selerotic and the diploetic paths of external acoustic cmeati could be indications for the "direct entrance" surgical approach, whereas the mixed type, either containing a little small cells or diploetic bone in sclerotic bone, might be suitable for this surgical approach also.

[Detection of human immunodeficiency virus infection in tuberculosis patients]

OBJECTIVE

Combined infection of human immunodeficiency virus (HIV) and Mycobacterium tuberculosis (MTB) has attracted wide attention. This study was to find out infection of HIV and occurrence of AIDS in tuberculosis patients.

METHODS

Primary screening was conducted in 2 973 inpatients with pulmonary tuberculosis by gelatin particle agglutination assay or rapid gold-labeled HIV 1 + 2 antibody assay. The HIV positive cases were sent to Beijing Municipal Center Laboratory for verification.

RESULTS

Three HIV positive cases were detected among 2,973 pulmonary tuberculosis patients with the positive rate of 1.01 per thousand. Two were male and 1 female with average age of 30 years (23, 27, and 40 years respectively) accounting for 2.86 per thousand of the 21 - 41 age group, among which 1 infected through intravenous drug injection, 2 by heterosexual behavior. And all the 3 HIV positive cases had developed to be AIDS.

CONCLUSIONS

Enough knowledge of the risk of combined HIV/MTB infection and high-degree alert should be emphasized in medical professionals involving in diagnosis, treatment and management of tuberculosis. Routine HIV antibody detection in high-risk tuberculosis patients for HIV infection, especially in young and middle-age tuberculosis patients, is helpful for early diagnosis and treatment of AIDS and avoiding its spreading.

[Immunocytochemical study of gamma-aminobutyric acid-ergic innervation in the end-organs of human vestibule]

OBJECTIVE

To investigate gamma-aminobutyric acid-ergic (GABAergic) innervation in the end-organs of human vestibule.

METHODS

A modified pre-embedding immunostaining technique of immunoelectron microscopy were applied to accomplish this study with a polyclonal antibody to gamma-aminobutyric acid.

RESULTS

GABA-immunoreactive products were confined to the nerve terminals, which were rich in synaptic vesicles and the non-myelinated fibers. The GABA-immunoreactive nerve fibers synapse with afferent calices surrounding the type I hair cells.

CONCLUSION

This study shows that GABAergic fibers of human vestibular end-organs belong to the vestibular efferent system.

Isolation and characterization of the human gene encoding Ito: further diversity by alternative mRNA splicing

The transient outward K+ current (Ito) in the heart is responsible for the initial phase of repolarization and for setting the plateau voltage of the ventricular action potential. Recently, Kv4.3 has emerged as the leading candidate alpha-subunit gene that underlies Ito in larger mammals such as dogs and humans. We have cloned the human Kv4.3 homolog and describe a carboxyl-terminal splice variant that inserts 19 amino acids with a consensus protein kinase C (PKC) phosphorylation site into the protein after the last membrane-spanning segment. The coding region of Kv4.3 is comprised of at least five exons and is located on chromosome 1p13.3. In the basal state the basic biophysical properties of both of the splice variants are identical.

Hepatocyte growth factor stimulates fetal gastric epithelial cell growth in vitro

BACKGROUND

The growth and development of the fetal gastrointestinal tract is likely mediated, in part, by peptide growth factors. We compared the mitogenic effects of graded doses of hepatocyte growth factor (HGF) to epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), and insulin-like growth factor-1 (IGF-1) on fetal rabbit gastric epithelial cells.

MATERIALS AND METHODS

Fetal rabbit gastric epithelial cells were purified by mechanical dissociation and selected culture and grown in short-term (24 h) and long-term (12 days) culture. Stimulation of fetal gastric epithelial cell growth in response to individual peptide growth factors was measured by [3H]thymidine incorporation and cell counting.

RESULTS

In short-term culture, HGF stimulated [3H]thymidine incorporation in a dose-dependent manner from a threshold at 10 pM to a maximum at 100 pM. For EGF and TGF-alpha, maximal stimulation occurred at 100 pM. For HGF, maximal [3H]thymidine incorporation was 3.6 +/- 0.7 times basal. For EGF and TGF-alpha, maximal [3H]thymidine incorporation was 4.3 +/- 0.4, and 3.6 +/- 0.4 times basal, respectively. For IGF-1, maximal [3H]thymidine incorporation was only 70% of the maximal effect observed for the other growth factors tested. Rabbit amniotic fluid increased [3H]thymidine uptake in a dose-dependent manner. In long-term culture, purification to greater than 90% epithelial cells was attained after 12 days treatment. For HGF, EGF, TGF-alpha, and 20% rabbit amniotic fluid, significant increases in cell number above control (P < 0.05) were observed at 1 nM concentrations. None of these individual factors, however, increased cell growth as significantly as that of 10% fetal bovine serum.

CONCLUSIONS

Our results suggest that: (1) HGF stimulates [3H]thymidine uptake and cell proliferation in fetal rabbit gastric epithelial cells in vitro, and (2) HGF's mitogenic effect on fetal rabbit gastric epithelial cell growth is comparable to that observed for EGF and TGF-alpha, but superior to the effect observed for IGF-1.

[Application of laser scanning confocal microscopy in inner ear morphological studies]

Laser scanning confocal microscope (LSCM) enables one to observe both the surface structure and the inner configuration in the same specimen, by its possibility of direct, non-invasive serial optical sectioning of whole mounted specimens. The potential value of LSCM in the field of inner ear morphological study was evaluated. The configuration of upper parts of organ of Corti was observed with the LSCM combined with double-stained fluorescence immunohistochemistry technique. The actin filament of hair cells by phalloidin, and the cytokeratin of supporting cells by monoclonal pan-anticytokeratin antibody. The stereocilia, cuticular plate, and the cuticle-free area of hair cells were well demonstrated. In the same specimen, the head plate of outer pillar cell, the phalangeal apical plate and the phalangeal process of Deiter cells were clearly showed as well. LSCM provide a new tool to the morphological study of organ of Corti.

[Immunocytochemical study of cholinergic innervation in the neurosensory epithelia of human vestibule]

OBJECTIVE

To investigate the cholinergic innervation of the neurosensory epithelia of human vestibule.

METHODS

A modified preembedding immunostaining technique for immunoelectronmicroscopy was applied to this study. A polyclonal antibody to choline acetyltransferase (ChAT) was used as the marker of cholinergic fibers.

RESULTS

ChAT-immunoreactive products were restricted to the nerve fibers and terminals which were rich in synaptic vesicles. The ChAT-immunoreactive fibers synaps with afferent chalice as well as with type II sensory hair cells.

CONCLUSION

This study demonstrates that cholinergic fibers innervate the neurosensory epithelia of human vestible. The cholinergic fibers of human vestibular sensory epithelia belong to the vestibular efferent system.

[Navelbine plus cisplatin combination therapy in the treatment of advanced non-small cell lung cancer: a report of 42 cases]

OBJECTIVE

To evaluate the results of combination chemotheray with navelbine (NVB) plus cisplatin (DDP) in the treatment of non-small cell lung cancer (NSCLC).

METHODS

From 1992 through 1996, 42 patients with advanced NSCLC were enrolled in this study. The median age of the patients was 57 years. Adenocarcinoma was the most common type of malignancy. Seventeen patients had stage IIIB disease and 25 had stage IV. Twenty-four patients had no prior chemotherapy and 18 received previous chemotherapy.

RESULTS

Partial response was observed in 20 patients with an overall response rate of 47.6%. The response appeared to correlate with dose intensity, as 54.2% response rate was achieved with a dose of NVB > or = 25 mg/m2/wk versus 38.9% response rate with NVB < 25 mg/m2/wk. The median response duration was 3.3 months and the median survival period was 8.5 months. The dose limiting toxicity was neutropenia which was seen in all treated cases (66.6% in grades III and IV). The local venous toxicity was observed in 40.5% of the patients.

CONCLUSION

A high response rate was obtained in advanced NSCLC treated by NVB plus DDP. NVB is a promising antitumor agent with tolerable toxicity.

[Effects of nimodipine on calcium currents in isolated outer hair cells of guinea pig cochlea]

The effects of nimodipine on calcium currents in outer hair cells isolated from guinea pig cochlea were investigated using a whole-cell recording patch-clamp technique. External application of nimodipine (10 mumol/L) caused a decrease of voltage-dependent calcium currents and an elevation of current-voltage curve. The half-maximal inhibition concentration of nimodipine inhibiting the voltage-dependent calcium currents was 60.14 nmol/L, and the maximal inhibition was 34.16%. The present results demonstrate that nimodipine reversiblly and partially blocks the voltage-dependent calcium currents in isolated outer hair cells of guinea pig cochlea in a concentration-dependent manner. It is suggested that nimodipine may be used in the treatment of Meniere disease through decreasing the influx of Ca2+ into the outer hair cells.

Luminal trypsin may regulate enterocytes through proteinase-activated receptor 2

Proteinase-activated receptor 2 (PAR-2) is a recently characterized G-protein coupled receptor that is cleaved and activated by pancreatic trypsin. Trypsin is usually considered a digestive enzyme in the intestinal lumen. We examined the hypothesis that trypsin, at concentrations normally present in the lumen of the small intestine, is also a signaling molecule that specifically regulates enterocytes by activating PAR-2. PAR-2 mRNA was highly expressed in the mucosa of the small intestine and in an enterocyte cell line. Immunoreactive PAR-2 was detected at the apical membrane of enterocytes, where it could be cleaved by luminal trypsin. Physiological concentrations of pancreatic trypsin and a peptide corresponding to the tethered ligand of PAR-2, which is exposed by trypsin cleavage, stimulated generation of inositol 1,4,5-trisphosphate, arachidonic acid release, and secretion of prostaglandin E2 and F1alpha from enterocytes and a transfected cell line. Application of trypsin to the apical membrane of enterocytes and to the mucosal surface of everted sacs of jejunum also stimulated prostaglandin E2 secretion. Thus, luminal trypsin activates PAR-2 at the apical membrane of enterocytes to stimulate secretion of eicosanoids, which regulate multiple cell types in a paracrine and autocrine manner. We conclude that trypsin is a signaling molecule that specifically regulates enterocytes by triggering PAR-2.

[Effects of streptomycin on ionic currents in isolated outer hair cells of guinea pig cochlea]

The effects of streptomycin on ionic currents in outer hair cells isolated from the cochlea of guinea pig were investigated using a whole-cell recording patch-clamp technique. External application of streptomycin (1 mmol/L) caused a decrease of the potassium currents and calcium currents, respectively. The half-maximal inhibition concentration of streptomycin checking the voltage-dependent calcium currents was 56.08 mumol/L, and the ratio of maximal inhibition 21.71%. The present results demonstrate that streptomycin partially irreversibly blocks the voltage-dependent calcium currents in dissociated outer hair cells of guinea pig cochlea in a concentration-dependent manner. The effects of streptomycin of the potassium currents may be, at least in part, the result of the inhibition of Ca2+ influx. It suggests that the inhibition of Ga2+ influx may be one of the ototoxic mechanisms of streptomycin on outer hair cells.

Innervation of cholinergic vestibular efferent system in vestibular periphery of rats

The innervation of cholinergic efferent fibers in the vestibular endorgans of the rats was investigated using a modified preembedding immunostaining technique of immunoelectron microscopy. A monoclonal antibody to choline acetyltransferase (ChAT) was used as a marker of cholinergic fibers. It was found that there were four types of cholinergic innervation in the vestibular endorgans of the rat: (1) cholinergic nerve endings formed axo-dendritic synapses with afferent chalice surrounding the type I sensory hair cells; (2) cholinergic nerve endings formed axo-somatic synapses with type II hair cells; (3) cholinergic fibers synapse with afferent nerve fibers and (4) a synaptic contact developed between cholinergic nerve endings. The results demonstrated that a multiform innervation of the cholinergic efferents exists in the rats vestibular periphery.

Organ distribution and biliary excretion of intravenously injected insulin-like growth factor-I in suckling rats

The organ distribution of intravenously injected 125I-IGF-I at a dose of 2-4 x 10(6) cpm or 5-10 ng/animal was studied in 10- to 12-day-old Sprague-Dawley rats at 5 and 30 min after injection. Results of the study suggest that, although the main portion of intravenous IGF-I remains in the circulation, significant amounts are also found in the carcass, liver and kidney. Blood radioactivity fell by 50% 30 min after injection, but concentrations in the carcass, liver, kidney and skin either remained stable or increased. Gel chromatography demonstrated that significant portions of radioactivity recovered from serum, liver and kidney coeluted in a position identical to the injected IGF-I. In addition, the extracted peptide bound competitively to a membrane IGF-I receptor preparation. Studies performed on liver and kidney from these animals 5 min after injection showed that on a per gram wet weight basis, these organs contained equivalent amounts of 125I-IGF-I. However, although by 30 min, 65% of the intact labelled IGF-I has been removed from the liver, the amount remaining in kidney tissue was equal to that noted 5 min after injection. Bile was collected over a 2-hour period and contained approximately 2% of the injected radioactivity and a significant portion (30%) of this radioactivity coeluted with native IGF-I. This material also bound competitively in a radioreceptor assay, suggesting 'intactness' of this peptide. From this study, we conclude that (a) IGF-I, when administered intravenously, remains for at least 30 min in a receptor-active form in blood and several organs; (b) IGF-I derived from the circulation is cleared from the liver more quickly than from the kidney of suckling rats, and (c) that IGF-I is transferred from blood to bile.

Molecular cloning, expression and potential functions of the human proteinase-activated receptor-2

We used PCR to amplify proteinase activated receptor-2 (PAR-2) from human kidney cDNA. The open reading frame comprised 1191 bp and encoded a protein of 397 residues with 83% identity with mouse PAR-2. In KNRK cells (a line of kirsten murine sarcoma virus-transformed rat kidney epithelial cells) transfected with this cDNA, trypsin and activating peptide (AP) corresponding to the tethered ligand exposed by trypsin cleavage (SLIGKV-NH2) induced a prompt increase in cytosolic calcium ion concentration ([Ca2+]i). Human PAR-2 (hPAR-2) resided both on the plasma membrane and in the Golgi apparatus. hPAR-2 mRNA was highly expressed in human pancreas, kidney, colon, liver and small intestine, and by A549 lung and SW480 colon adenocarcinoma cells. Hybridization in situ revealed high expression in intestinal epithelial cells throughout the gut. Trypsin and AP stimulated an increase in [Ca2+]i in a rat intestinal epithelial cell line (hBRIE 380) and stimulated amylase secretion in isolated pancreatic acini. In A549 cells, which also responded to trypsin and AP with mobilization of cytosolic Ca2+, AP inhibited colony formation. Thus PAR-2 may serve as a trypsin sensor in the gut. Its expression by cells and tissues not normally exposed to pancreatic trypsin suggests that other proteases could serve as physiological activators.

[Mechanism of plasma endothelin-1 level elevation and its relation with pulmonary hypertension in chronic cor pulmonale]

To explore the mechanism of plasma endothelin-1 (ET-1) level elevation and its relation with pulmonary hypertension in chronic cor pulmonale, plasma ET-1 level was measured by using radioimmunoassay in 21 cases of chronic cor pulmonale with acute exacerbation and cardiac catheterization was performed simultaneously. Results, Peripheral venous plasma ET-1 level of the patients was significantly higher than that of controls and also higher than that of peripheral arterial and pulmonary arterial plasma ET-1 level of the patients themselves. The plasma ET-1 level of patients had a significant negative correlation with PaO2 and SaO2 and positive correlation with mean pulmonary arterial pressure (PAPM) and pulmonary vascular resistance index (PVRI). 9 of the patients were treated with mechanical ventilation. After ventilation, PaO2 went up notably and plasma ET-1 level decreased remarkably, PAPM and PVRI also reduced simultaneously.

CONCLUSIONS

The causes of plasma ET-1 level elevation in cor pulmonale may be as follows, Firstly, pulmonary alveolar hypoxia increases the release of ET-1 in lungs; Secondly, the ability of the lungs to clean ET-1 decreases because of pulmonary abnormality. High level of plasma ET-1 may induce pulmonary hypertension. The level of plasma ET-1 can be lowered by correcting hypoxic status of the patients and the resulting improvement of pulmonary hemodynamics.

Dendritic cells in the normal human tympanic membrane

Dendritic cells (DCs) are antigen-presenting cells that possess an outstanding capacity to initiate primary immune responses. They reside in the tissues in an immunologically immature state. Upon antigenic challenge in vivo or short-term culture in vitro, they undergo a maturation process and turn into mature "lymphoid DCs." Langerhans cells (LCs) of the epidermis were identified as members of this DC system. They have been demonstrated in cholesteatoma matrix and in inflamed tympanic membranes, but the normal tympanic membrane was hitherto thought to be devoid of them. To clarify this question, we removed 12 normal tympanic membranes postmortem and processed them for a sheet preparation. The epidermal layers were peeled off and immunostained with the following monoclonal antibodies: HLA-DR, OKT6/CD1a, and LAG (specific for the Birbeck granules of LCs). Two tympanic membranes were also processed for routine electron microscopy. In all epidermal sheets a dense network of DCs could be demonstrated. They showed a positive immunostaining reaction with HLA-DR, but a negative one with OKT6 and LAG. Thus, they differ in their immunohistochemical properties from typical epidermal LCs. At the ultrastructural level, DCs could also be identified, but without the typical Birbeck granules. This explains the negative reaction with the LAG antibody. These findings were extended and supported by a tissue culture examination of three normal tympanic membranes. After 3 days, typical "veiled" cells (ie, mature DCs), showing positive immunostaining with HLA-DR, could be recovered from the culture medium. In an oxidative mitogenesis assay, these cells displayed strong stimulatory capacity for resting T lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Cancellous bone Young's modulus variation within the vertebral body of a ligamentous lumbar spine--application of bone adaptive remodeling concepts

Bone remodeling theory based on strain energy density (SED) as the feedback control variable was used in conjunction with the finite element method to analyze the shape of the vertebral bodies within the ligamentous motion segment. The remodeling theory was once again applied to the altered two motion segments model to predict the Young's modulus distribution of the cancellous bone within the vertebral bodies. A three-dimensional finite element model of the two motion segments ligamentous lumbar spine (L3-5) was developed. Bone remodeling response (external as well as internal) of the motion segments to a uniaxial compressive load of 424.7 N was studied. The external shape of the converged model matched the normal shape of a vertebral body. The internal remodeling resulted in regional cancellous bone Young's moduli (or bone density) distributions similar to those reported in the literature; posterocentral regions of the vertebrae were predicted to have greater values of the elastic modulus than that of the outer regions. The results of the present study suggest that vertebral body assumes an adequate/optimum structure in terms of both its shape and its elastic moduli distribution within the cancellous region in response to the applied load. Extensions of the present model and its clinically relevant applications are discussed.

Presence of insulin-like growth factor I but absence of the binding proteins in the bile of rats

Whereas insulin-like growth factor I (IGF-I) has been found in various body fluids from different species, the presence or absence of IGF and associated binding proteins (IGFBPs) in bile has not been clearly defined. Bile concentration of IGF-I was measured in this study and found to be highest in the neonate and lowest in adult rats [133 +/- 15.9, 79.4 +/- 10.5, 45.3 +/- 12.7 ng/ml (mean +/- SE) in 12-day-old, 33-day-old, and adult rats, respectively]. When bile delivery rates of IGF-I (i.e., the product of IGF-I concentration in bile and the biliary flow rate) were calculated, IGF-I delivery was highest in weanling rats (469 pg.h-1.g body wt-1). When expressed as amount of IGF-I in bile delivered per day, however, delivery rates rose from 0.2 micrograms/day in the suckling and remained constant at 1.6-1.7 micrograms/day in both weanling and adult animals. Bile samples exposed to a placental membrane IGF receptor preparation showed significant dose-dependent inhibition of binding of native IGF-I. Because no IGF binding proteins were identified by Western ligand blot or by Sephadex gel chromatography, the results suggest the presence of biologically significant quantities of bioactive IGF-I in bile. We speculate that IGF-I in bile may play an important role in the growth of the gastrointestinal tract, both in the suckling as well as later in life.

High density cultivation of a recombinant CD-1 cell line producing prourokinase using a Biosilon microcarrier culture system

CD-1, a genetically-engineered CHO cell line, was cultivated with a Biosilon microcarrier culture system. We successfully cultivated CD-1 cells to a very high density (over 1 x 10(7) cells/ml). Prourokinase was stably secreted at about 180 IU/10(6) cells/24 h. Experiments showed that CD-1 cells growing on Biosilon microcarriers were able to spontaneously release from the microcarriers, then reattach and proliferate on fresh microcarriers. This makes it very easy to scale up production. The microcarriers could be reused several times without affecting adhesion, proliferation and prourokinase secretion. With CM-PECC membrane radial flow chromatography and MPG chromatography, the prourokinase in conditioned medium could be purified to a specific activity of 1 x 10(5) IU/mg of protein. The purification factor was about 600 fold, and approximately 90% of the biological activity was recovered.

Investigation of vibration characteristics of the ligamentous lumbar spine using the finite element approach

A nonlinear, three-dimensional finite element model of the ligamentous L4-S1 segment was developed to analyze the dynamic response of the spine in the absence of damping. The effects of the upper body mass were simulated by including a mass of 40 kg on the L4 vertebral body. The modal analyses of the model indicated a resonant frequency of 17.5 Hz in axial mode and 3.8 Hz in flexion-extension mode. Accordingly, the predicted responses for the cyclic load of -400 +/- 40 N applied at four different frequencies (5, 11, 16.5, and 25 Hz) were compared with the corresponding results for axial compressive static loads (-360, and -440 N). As compared to the static load cases, the predicted responses were higher for the cyclic loading. For example, the effect of cyclic load at 11 Hz was to produce significant changes (9.7-19.0 percent) in stresses, loads transmitted through the facets, intradiscal pressure (IDP), disk bulge, as compared to the static load predictions. The responses were found to be frequency dependent as well; supporting the in vivo observations of other investigators that the human spine has a resonant frequency. For example, the 11 Hz model (DYN11) compared to the DYN5 model showed an increase in majority of the predicted parameters. The parameters showed an increase with frequency until 17.5 Hz (resonant frequency of the model); thereafter a decrease at 25 Hz.(ABSTRACT TRUNCATED AT 250 WORDS)

Stress analysis of a canine spinal motion segment using the finite element technique

Canine models have been frequently employed to investigate the in vivo effects of a surgical procedure. Various studies indicate that canine models can provide a successful in vivo biological model for these studies. Use of canine models for the biomechanical studies of the spine, however, have been questioned because of different loading conditions on the canine and human spines originated from posture differences between canine and human. Similarities between the stress distributions within the canine and human motion segments under physiological loads will strengthen the use of canine models for the studies of spine biomechanics. In the present study, finite element models of the canine intact and stabilized motion segments were developed to investigate these aspects. Comparison of model predicted flexion angle, axial stiffness, and facet contact force for the canine intact L6-L7 motion segment revealed good agreement with the corresponding parameters experimentally measured under the similar loading conditions. Similar stress distributions within the intact canine and human models were found from the predicted results in response to the physiological load. Stabilizing and stress-shielding effects of a pedicle screw-plate-type fixation device [variable spinal plating (VSP)] on the stabilized motion segment were also similar for the canine and human stabilized models. Furthermore, maximum stresses in the pedicle screws were found at the junction between the bone screw and the integrated nut of the inferior screw in both the canine and human stabilized models. This corresponds to the location of pedicle screw breakage reported in the literature. These findings suggest that a canine is a suitable model for the biomechanical studies of the lumbar spine.

A 9-year follow-up study of the immunogenicity and long-term efficacy of plasma-derived hepatitis B vaccine in high-risk Chinese neonates

The long-term immunogenicity of and protection provided by a plasma-derived hepatitis B vaccine was determined in a cohort of 98 susceptible Chinese neonates immunized in 1982-1983. Within 24 hours of birth, 89 infants received the first of three 30-micrograms doses of vaccine (at 0, 1, and 6 months) and were subsequently followed up by testing for serological markers of hepatitis B virus and by determining levels of alanine aminotransferase annually for 9 years. After the primary series of vaccine doses, 74 (83%) of 89 subjects developed antibody to hepatitis B surface antigen (anti-HBs). At the 9-year follow-up, 51% of vaccinees still had levels of antibody of > or = 10 mIU/mL, considered the protective level. Seven responders to vaccine (9.4% of 74 evaluable patients) developed antibody to hepatitis B core antigen, and in six of these responders, levels of anti-HBs increased transiently. None of the vaccinees developed chronic carriage of hepatitis B surface antigen or clinical hepatitis. Immunization of high-risk neonates with a plasma-derived hepatitis B vaccine can induce long-lasting protective immunity that can prevent or modify primary infection for at least 9 years. Booster doses are not necessary during this period.

A combined finite element and optimization investigation of lumbar spine mechanics with and without muscles

A combined finite element and optimization approach to study the effects of muscles on the biomechanics of the lumbar spine was initiated. Briefly, a three-dimensional, nonlinear, finite element model of a ligamentous L3-4 motion segment was formulated (LIG model) for the predictions of stresses, etc., in the motion segment. A separate, biomechanical optimization-based force model with experimental input was developed to predict the forces in muscles and disc across the L3-4 segment in response to a person holding 90 N in his hands with spine flexed 30 degrees, and knees straight. The predicted muscle forces from the optimization model were then incorporated into the L3-4 finite element model as nodal forces to simulate the muscle action (MUS model). The predicted responses from the muscles active (MUS) finite element model were compared to the corresponding results from the ligamentous (LIG) finite element model subjected to an equivalent load. The biomechanical parameters compared were: translation and rotation of L3, disc bulge, intervertebral foramen gap, intradiscal pressure, facet loading, ligament tension, compressive disc load, and stresses in the vertebral body. The addition of muscular forces in the MUS model led to a decrease in the anteroposterior translation and flexion rotation (displacements in the sagittal plane) of the segment compared to the corresponding LIG model predictions. Thus, the muscles imparted stability to the ligamentous segment. The presence of muscles also led to a decrease in stresses in the vertebral body, the intradiscal pressure and other mechanical parameters of importance. However, the load bearing of the facets increased compared to the ligamentous model. Thus, facets play a significant role in transmitting loads in a normal intact spine. These results, for the first time, provide quantitative data on the stabilizing effects of muscles on the mechanics of a ligamentous spine. The results also provide a scientific explanation in support of the "degenerative cascade" concept proposed in the literature. The model predictions, in conjunction with the degenerative cascade concept, also support the observation that the osteoarthritis of facets may follow disc degeneration. Future research directions based on the current model are presented.

Pilot production of high-titer interferon and virus with a microcarrier suspension culture system

We have successfully cultured four cell lines--L929, BHK-13, BHK-21 and CHO-K1 using an MC-1 type microcarrier made in our academy. With the microcarrier in a concentration of 5 mg/ml, the cell density was about 30 x 10(4) cells/ml; after 3 days in suspension culture, the cells could proliferate to 1 x 10(6) cells/ml. At this time, when L929 cells were primed with 25 IU/ml MuIFN for 14-24 h and then superinduced with NDV, cycloheximide (20 micrograms/ml) and actinomycin D (2 micrograms/ml), the titer of IFN reached approximately 10(5) IU/ml (10(5) IU/mg of protein, expressed in specific activity). When VSV was inoculated into the other three cell line cultures, the viral titer reached 6 Log TCID50/ml or much higher. The yield with the CHO-K1 cell line was the highest, reaching titers of 7-8 Log TCID50/ml. These titers were similar to those seen in stationary culture. With trypsin-citrate solution and a more rapid stirring speed, the cells could be satisfactorily released from the microcarriers and reattached on fresh ones. These experiments show that the microcarrier suspension culture system is suitable for producing large scale, high-titer, low-cost vaccines and IFNs, both natural and recombinant, using genetically-engineered CHO cell lines.

[Isolation and characteristics of Borrelia burgdorferi from Ixodes persulcatus]

We reported the detailed characteristics of Lyme disease spirochetes (Borrelia burgdorferi), strain H7, isolated from Ixodes persulcatus in Heilongjiang. Cells of strain H7 were 9.8--26.5 microns long and 0.13--0.35 microns wide. There were 1--11 waves with a wavelength of 1.2--3.0 microns and an amplitude of 0.59--1.13 microns. Direction of spires was left. Seven flagella were inserted subterminally at each end of the cell and ends were pointed. 31 degrees C was the optimum cultural temperature in vitro. The major constitutional and antigenic proteins were 21k, 32k and 34k proteins. H7 could react on the patient sera of Xinjiang and Heilongjiang with IFA and western blot. These findings demonstrated that strain H7 belonged to species Borrelia burgdorferi, but was a new "subtype" which differed from the strains isolated from other areas and vectors.

Luteotropic and luteolytic responsiveness of ovine luteal cells in long-term culture

Ovine luteal cells were collected and plated 36 h (Day 2) after injection of human chorionic gonadotropin (Day 0) to induce ovulation. Cells were maintained (Days 2-12) in Medium 199 containing 5% calf serum, which was replaced daily. Progesterone secretion was not stimulated (p greater than 0.05) by luteinizing hormone (LH, 10 ng/ml or 100 ng/ml) at any time during culture. However, it was enhanced (p less than 0.05) with a 24-h pulse of dibutyryl adenosine 3', 5'-monophosphate (dbcAMP) during early (2.2-fold stimulation over basal; Days 5,6) or mid- (1.7-fold stimulation over basal: Days 8,9) culture if the pulsing medium contained serum, but not if serum had been withdrawn for 24 h. Continuous exposure of cultures to dbcAMP (2 mM, Days 3-12) resulted in continuously stimulated (p less than 0.05) progesterone secretion (range 1.8- to 4.1-fold stimulation). An increased (p less than 0.05) percentage of cells staining positive for 3 beta-hydroxy-delta 5-steroid dehydrogenase-delta 5, delta 4-isomerase (3 beta HSD) activity were recovered on Day 12 in cultures incubated (Days 3-12) with dbcAMP. Incubation of cultures continuously with prostaglandin F2 alpha (PGF2 alpha) produced dose-dependent inhibition (p less than 0.05) of progesterone secretion. Reduced numbers of 3 beta HSD-positive cells were recovered from these incubations. These experiments demonstrate luteotropic (dbcAMP) as well as luteolytic (PGF2 alpha) effects on ovine luteal cells in long-term culture. This study provides evidence that these cultures will be useful for investigating the development of hormonal regulation of luteal function.

Protein kinase A and C activities and endogenous substrates in ovine small and large luteal cells

Protein kinase A (cAMP-dependent) and C (calcium, phospholipid-dependent) activities were measured and in vitro phosphorylation of endogenous proteins by these kinases were observed by SDS-PAGE in 100,000 x g supernatant (soluble) fractions of ovine small (12-22 microns) and large (greater than 22 microns) luteal cells. No differences in stimulation (P less than 0.05) of A kinase activity between small and large cells were detected. Protein kinase C activity was stimulated (P less than 0.05) 2.9-fold in small cells but not significantly enhanced above basal (P greater than 0.05) in large cells. By direct comparison, greater stimulation (P less than 0.05) over basal of A versus C kinase (6.1- versus 2.9-fold) was measured in small cells. These stimulations were greater than those observed in large cells (A kinase, 4.8-fold; C kinase, 1.8-fold). Maximal specific activities of both kinases (per mg protein) were greater (P less than 0.05) in small than in large cells. Endogenous proteins that could serve as substrates for phosphorylation by A and C kinases differed between small and large cells. Phosphorylation of six proteins by A kinase was consistently greater in small than in large cells. One endogenous protein (37 kDa) appeared to serve as a preferred substrate for phosphorylation by A kinase in small cells and C kinase in large cells. One protein (81 kDa) was predominantly phosphorylated in large rather than small cells by a calcium-dependent, C kinase-independent mechanism. These results support the accepted role of cAMP via A kinase and a possible role for C kinase in regulating steroidogenesis in ovine small luteal cells. The inability of large cells to respond to cAMP with enhanced secretion of progesterone may be due to an unavailability of phosphoprotein substrates for A kinase. Furthermore, protein kinase C activity and available protein substrates display quantitative and qualitative differences between small and large cells. Differences in regulation of steroidogenesis between the cell types may be due to these observed differences.

Steroidogenic capacity and ultrastructural morphology of cultured ovine luteal cells

Corpora lutea were surgically collected from superovulated ewes 36 h post-injection of human chorionic gonadotropin (hCG) (Day 2), dissociated (0.2% collagenase), plated, and maintained in culture Days 2-10 in Medium 199 supplemented with 5% calf serum. Accumulation of progesterone in the cultures did not decrease (p greater than 0.05) from Day 3 (17.5 +/- 5.1 nmol/10(6) cells) to Day 10 (4.8 +/- 1.7 nmol/10(6) cells). Calf serum (5%) in the medium supported greater (p less than 0.05) progesterone production than fetal calf serum (5%) or medium without added serum. Steroidogenic cells did not increase (Days 2-10) in numbers, but increased (p less than 0.01) in mean cell diameter (Day 2, 11.7 +/- 0.4 micron; Day 10, 24.5 +/- 1.6 micron). Steroidogenic capacity on Day 10 of cells cultured Days 2-10 (in vitro) was not different (p greater than 0.05) from that of cells collected from the ovary on Day 10 (in vivo); however, steroidogenic cells recovered from plates had greater (p less than 0.01) mean cell diameters (24.5 +/- 1.6 micron, in vitro, compared to 15.2 +/- 1.0 micron, in vivo). Transmission electron microscopy revealed that cultured cells (Days 5, 10) possessed less smooth endoplasmic reticulum but more lipid droplet inclusions, ribosomes, and rough endoplasmic reticulum than cells obtained in situ (Day 10). Electron-dense secretory granules were rarely seen. Although subcellular morphology of ovine luteal cells in culture was altered, these changes did not appear to significantly affect the ability of these cells to produce progesterone.