Effect of Korea red ginseng on the blood pressure in conscious hypertensive rats

The change of blood pressure and heart rate after intravenous injection of Korea red ginseng (KRG) were studied in the conscious normotensive and one-kidney, one-clip Goldblatt hypertensive (1K, 1C-GBH) rats. Crude saponin (CS) of KRG (50, 100 mg/kg i.v.) induced a hypotensive effect and bradycardia in a dose-dependent manner in the anesthetized rats. On the other hand, CS of KRG (100 mg/kg) induced a hypotensive effect and reflex tachycardia in the conscious rats. Saponin-free fraction (SFF) of KRG did not affect them in the anesthetized normotensive rats (P>.05). The maximal hypotensive effect by CS of KRG in the conscious 1K, 1C-GBH hypertensive rats and L-nitroarginine methyl ester (L-NAME, 40 mg/kg)-treated conscious hypertensive rats was not different from that of conscious normotensive rats (Delta 31.6+/-6.3, Delta 27.5+/-5.8 vs. Delta 26.7+/-4.3 mmHg, P>.05). However, pretreatment of L-NAME significantly inhibited the reflex tachycardia by CS of KRG (70.8+/-7.0 vs. 30.6+/-15.0 bpm, P<.05). Hemolysate-sensitive nitric oxide (NO) current by the CS of KRG was greater than that of the SFF of KRG (651.9+/-128.2 pA for CS and 164.9+/-92.5 pA for SFF, P<.001). These findings suggest that KRG has a hypotensive effect and its effect may be due to saponin fraction of KRG in the conscious rats. The releasing effect of NO of KRG, like NO donor, may be partly contributed to the hypotensive effect of KRG.

Depressed interleukin-12 (IL-12), but not IL-18, production in response to a 30- or 32-kilodalton mycobacterial antigen in patients with active pulmonary tuberculosis

The secreted 30-kDa antigen (Ag) of Mycobacterium tuberculosis directly stimulates Th1-type protective cytokine responses in healthy tuberculin reactors but not in patients with active tuberculosis (TB). To examine the cytokine profiles attributable to Th1 suppression associated with active TB, interleukin-12 (IL-12), IL-18, and IL-10 production in response to a 30- or 32-kDa Ag in 16 patients with active pulmonary TB and 24 healthy controls was investigated by enzyme-linked immunosorbent assay. In TB patients, production of IL-12 p40, as well as gamma interferon (IFN-gamma), by 30- or 32-kDa Ag-stimulated peripheral blood mononuclear cells (PBMC) was significantly decreased compared with that in healthy tuberculin reactors. There were no significant differences in IL-18 production between patients and controls early during stimulation (16 h). However, PBMC from patients showed significantly enhanced IL-18 proteins after 96 h of stimulation. Similarly, higher IL-10 production was observed in the TB patients than in healthy tuberculin reactors. After 2 months of anti-TB therapy, the mean IFN-gamma and IL-12 p40 production and the mean blastogenic responses were significantly increased in PBMC in the 10 TB patients who were followed up. Our findings provide evidence that depressed IL-12 in response to the 30- or 32-kDa Ag is involved in the immunopathogenesis of human active pulmonary TB.

Pattern of deposition of stainless steel welding fume particles inhaled into the respiratory systems of Sprague-Dawley rats exposed to a novel welding fume generating system

In order to investigate occupational diseases related to welding fume exposure, such as nasal septum perforation, pneumoconiosis and manganese intoxication, we built a welding fume exposure system that included a welding fume generator, exposure chamber and fume collector. The fume concentrations in the exposure chamber were monitored every 15 min during a 2-h exposure. Fume (mg/m(3)) concentrations of major metals, including Fe, Mn, Cr, and Ni were found to be consistently maintained. An acute inhalation toxicity study was conducted by exposing male Sprague-Dawley rats to the welding fumes generated in this apparatus by stainless steel arc welding. The rats were exposed in the inhalation chamber to a welding fume with a concentration of 62 mg/m(3) total suspended particulates for 4 h. Animals were sacrificed at 4 h and at 1, 3, 7, 10, and 14 days after exposure. Histopathological examinations were conducted on the animals' upper respiratory tracts, including the nasal pathway and the conducting airway, and on the gas exchange region including the alveolar ducts, alveolar sacs, and alveoli. Diameters of fume particles varied from 0.02 to 0.81 microm and were distributed log normally, with a mean diameter of 0.1 microm and geometric standard deviation of 1.42. Rats exposed to the welding fume for 4 h did not show any significant respiratory system toxicity. The mean particle diameter of 0.1 microm resulted in little adsorption of the welding fume particles in the upper respiratory tract. Particle adsorption took place principally in the lower respiratory tracts, including bronchioles, alveolar ducts, alveolar sacs, and alveoli.

Formulas for transverse ionization cooling in solenoidal focusing channels

Ionization cooling in solenoidal channels, such as that envisioned for the future muon colliders or neutrino factories, is studied. Assuming that the interaction with the ionization material is weak, the evolution of the transverse emittance and angular momentum can be determined analytically. Simple and practical formulas are derived for a general cooling configuration as well as for periodic channels. The prediction of these formulas agrees well with those obtained from simulation codes. The method developed here should be useful to other areas of beam physics involving solenoidal focusing.

Study of cytochrome bo function in Vitreoscilla using a cyo(-) knockout mutant

The bacterium, Vitreoscilla, produces a delta mu(Na+) across its membrane during respiration. A key enzyme for this function is the cytochrome bo terminal oxidase which, when incorporated into synthetic proteoliposomes, pumps Na(+) across the membrane upon the addition of a substrate. A Vitreoscilla cytochrome bo knock out (cyo(-)) mutant was isolated by transposon mutagenesis using pUT-mini-Tn5Cm. The membranes of this mutant lacked the characteristic 416 nm peak and 432 nm trough in CO difference spectra, which are clearly visible in spectra of the Vitreoscilla wild-type, but peaks at 627, 560, and 530 nm in reduced minus oxidized difference spectra indicate that cytochrome bd is still present. The specific NADH oxidase and ubiquinol-1 oxidase activities of the cyo(-) mutant membranes were less than those of Vitreoscilla wild-type and Escherichia coli membranes, and the stimulation of these activities of the mutant and E. coli membranes by 75 mM NaCl was approximately 50% less than that of Vitreoscilla wild-type membranes. The ubiquinol-1 oxidase activity of the cyo(-) mutant membranes was inhibited by 10 mM KCN to a lesser degree than that of the Vitreoscilla wild-type and E. coli membranes (50, 80, and 85%, respectively). This result is also consistent with the cyo(-) mutant membrane fragments containing only the cytochrome bd terminal oxidase, which is known to be less sensitive to KCN. Although the maximum respiration and growth of the cyo(-) mutant were less than those of the wild-type, this mutant is still capable of growing with cytochrome bd alone.

The phylogeny of the Asteridae sensu lato based on chloroplast ndhF gene sequences

A phylogenetic study of Asteridae sensu lato was conducted based on chloroplast ndhF gene sequences for 116 ingroup and 13 outgroup species. Prior molecular studies based on rbcL sequences identified terminal groups corresponding to families, but were unable to resolve relationships among them. These results are largely consistent with earlier rbcL studies, but provide much greater resolution and stronger bootstrap support throughout the tree. The parsimony analysis found eight equally parsimonious trees, all of which recognize four major clades with the following relationship: (Cornales (Ericales (Euasterids I, Euasterids II))). Euasterids I includes (Garryales ((Solanales, Boraginaceae) (Gentianales, Lamiales))), although with weak support for relationships among the named clades. Euasterids II includes (Aquifoliales (Asterales (Apiales, Dipsacales))) with strong support for these relationships. Relationships within Ericales are weakly supported and merit further attention.

Joint fluid from patients with failed total hip arthroplasty stimulates pit formation by mouse osteoclasts on dentin slices

Periprosthetic bone resorption has been implicated in the failure of total joint arthroplasty. Osteolysis is reported to be associated with bone resorption induced by bone-resorbing cytokines, which are released from macrophages and fibroblasts in periprosthetic tissues after stimulation by wear debris generated in the joint cavity. Recent reports have suggested the concept of the effective joint space, which includes all periprosthetic regions that are accessible to joint fluid and wear debris. In this study, we examined the levels of interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), and tartrate-resistant acid phosphatase (TRAP) in joint fluid after failed total hip arthroplasty (THA) with osteolysis and investigated whether the joint fluid could activate osteoclastic bone resorption using unfractionated mouse bone cells cultured on dentin slices. Histochemical analysis showed the presence of more TRAP-positive cells in synovial capsules from failed THA patients when compared with osteoarthritis (OA) patients (controls). The levels of IL-6, sIL-6R, and TRAP in joint fluid from failed THA patients were significantly higher than in OA patients. Mouse osteoclasts cultured on dentin slices with joint fluid from failed THA patients with osteolysis produced a significant increase of pit area, whereas cells cultured with joint fluid from OA patients did not. Interestingly, osteoclastic bone resorption on dentin slices was significantly correlated with TRAP activity in joint fluid (p < 0.0001). These results suggest that joint fluid containing bone-resorbing cytokines is produced by synovial capsules in failed THA patients with osteolysis and may activate osteoclasts around the prosthesis in combination with those produced by interface tissues, thus contributing to periprosthetic bone resorption.

Dynamic glenohumeral stability provided by the rotator cuff muscles in the mid-range and end-range of motion. A study in cadavera

BACKGROUND

Both static and dynamic factors are responsible for glenohumeral joint stability. We hypothesized that dynamic factors could potentially operate throughout the entire range of glenohumeral motion, although capsuloligamentous restraints (a static factor) have been thought to be primarily responsible for stability in the end-range of motion. The purpose of this study was to quantitatively compare the dynamic glenohumeral joint stability in the end-range of motion (the position of anterior instability) with that in the mid-range by investigating the force components generated by the rotator cuff muscles.

METHODS

Ten fresh-frozen shoulders from human cadavera were obtained, and all soft tissues except the rotator cuff were removed. The glenohumeral capsule was resected after the rotator cuff muscles had been released from the scapula. A specially designed frame positioned the humerus in 60 degrees of abduction and 45 degrees of extension with respect to the scapula. The compressive and shear components on the glenoid were measured before and after a constant force was applied individually to each muscle with the humerus in five different positions (from neutral to 90 degrees of external rotation). The dynamic stability index, a new biomechanical parameter reflecting these force components and the concavity-compression mechanism, was calculated. The higher the dynamic stability index, the greater the dynamic glenohumeral stability.

RESULTS

In the mid-range of motion, the supraspinatus and subscapularis provided higher dynamic stability indices than did the other muscles (p < 0.05). On the other hand, when the position of anterior instability was simulated in the end-range of motion, the subscapularis, infraspinatus, and teres minor provided significantly higher dynamic stability indices than did the supraspinatus (p < 0.005).

CONCLUSIONS

The rotator cuff provided substantial anterior dynamic stability to the glenohumeral joint in the end-range of motion as well as in the mid-range.

CLINICAL RELEVANCE

A glenohumeral joint with a lax capsule and ligaments might be stabilized dynamically in the end-range of motion if the glenoid concavity is maintained and the function of the external and internal rotators, which are efficient stabilizers in this position, is enhanced.

Intradural extramedullary tuberculoma of the spinal cord: a case report

Intradural extramedullary (IDEM) tuberculoma of the spinal cord is uncommon entity and moreover, few reports have been documented on concurrent IDEM and intracranial tuberculomas. Authors report a case of IDEM spinal tuberculoma having intracranial lesion simultaneously. A 49-year-old woman suffered from paraparesis and urinary incontinence while being given medical treatment for tuberculous meningitis. Magnetic resonance imaging (MRI) revealed an IDEM mass lesion between the T1 and T2 spinal levels, and multiple intracranial tuberculous granulomas. Surgical resection of the IDEM tuberculoma followed by anti-tuberculous medication resulted in good outcome.

Apo2L/TRAIL-dependent recruitment of endogenous FADD and caspase-8 to death receptors 4 and 5

Fas (APO-1/CD95) and tumor necrosis factor receptor 1 (TNFR1) trigger apoptosis by recruiting the apoptosis initiator caspase-8 through the adaptor FADD. Fas binds FADD directly, whereas TNFR1 binds FADD indirectly, through TRADD. TRADD alternatively recruits the NF-kappaB-inducing adaptor RIP. The TNF homolog Apo2L/TRAIL triggers apoptosis through two distinct death receptors, DR4 and DR5; however, receptor over-expression studies have yielded conflicting results on the ligand's signaling mechanism. Apo2L/TRAIL induced homomeric and heteromeric complexes of DR4 and DR5 and stimulated recruitment of FADD and caspase-8 and caspase-8 activation in nontransfected cells. TRADD and RIP, which bound TNFR1, did not bind DR4 and DR5. Thus, Apo2L/TRAIL and FasL initiate apoptosis through similar mechanisms, and FADD may be a universal adaptor for death receptors.

Pharmacological modulation of fluid secretion in the pigmented rabbit conjunctiva

We determined net fluid secretion rate across the pigmented rabbit conjunctiva in the presence and absence of pharmacological agents known to affect active Cl- secretion and Na+ absorption. Fluid flow across a freshly excised pigmented rabbit conjunctiva mounted between two Lucite half chambers was measured by a pair of capacitance probes in an enclosed cabinet maintained at 37 degrees C and a relative humidity of 70%. Fluid transport was also measured in the presence of compounds known to affect active Cl- secretion (cAMP, UTP, and ouabain), Na+ absorption (D-glucose), or under the Cl--free condition on both sides of the tissue. Net fluid secretion rate across the pigmented rabbit conjunctiva in the serosal-to-mucosal direction at baseline was 4.3+/-0.2 microl/hr/cm2 (mean +/- s.e.m.). Net fluid secretion rate was increased approximately two-fold by mucosally applied 1 mM 8-Br cAMP (8.4+/-0.4 microl/hr/cm2) and 10 microM UTP (9.8+/-0.6 microl/hr/cm2), but was abolished by either serosally applied 0.5 mM ouabain (0.3+/-0.1 microl/hr/cm2) or under the Cl--free conditions (0.06+/-0.04 microl/hr/cm2). Mucosal addition of 20 mM D-glucose decreased net fluid secretion rate to 1.0+/-0.5 microl/hr/cm2. In conclusion, the pigmented rabbit conjunctiva appears to secrete fluid secondary to active Cl- secretion. This net fluid secretion is subject to modulation by changes in active Cl- secretion rate and in mucosal fluid composition such as glucose concentration.

Rates of protein transport across rat alveolar epithelial cell monolayers

The transport of model proteins, ranging from 12,300 to 150,000 Da, across tight rat alveolar epithelial cell monolayers (> 2000omegacm2) grown on polycarbonate filters, was studied. Model proteins were 14C-cytochrome c, 14C-ovalbumin, granulocyte-colony stimulating factor (G-CSF), 14C-bovine serum albumin (BSA), 125I-transferrin, and 14C-immunoglobulin G. Cytochrome c was extensively metabolized, as indicated by < 10% of the dose being translocated in intact form. This contrasts with 20-80% for the other model proteins studied. The flux of cytochrome c and G-CSF was symmetric in the apical-to-basolateral (ab) and basolateral-to-apical (ba) directions. By contrast, the flux of intact ovalbumin, BSA, transferrin and immunoglobulin G showed asymmetry, with the ab flux being higher by 2-5 times. There was no relationship between ab or ba fluxes and the molecular weights of these four model proteins. Since some of the proteins were translocated at much greater rates than are consistent with restricted diffusion or pinocytosis, receptor-mediated or adsorptive transcytosis may be involved.

Alpha1-adrenoceptors involvement in painful diabetic neuropathy: a role in allodynia

To investigate whether alpha1-adrenoceptors are involved in pain behaviors in streptozotocin (STZ)-induced diabetic rats, we measured the effects of phenylephrine or prazosin on allodynia in the diabetic rats. Phenylephrine aggravated allodynia, while prazosin alleviated allodynia in the diabetic rats. We also measured alpha1-adrenoceptors gene expression or density of [3H]-prazosin binding sites in the dorsal root ganglia (DRG) and spinal cord in painful diabetic rats. Alpha1-adrenoceptors mRNA and density of [3H]prazosin binding sites were increased in the DRG of the diabetic rats, however there were no significant differences in alpha1-adrenoceptors expression in the spinal cord between the control and diabetic rats. These results suggest increased alpha1-adrenoceptors in the DRG may play a role in the pathogenesis of painful diabetic neuropathy.

Pediatric intractable epilepsy: the role of presurgical evaluation and seizure outcome

Surgical experience with long-term follow-up is limited in childhood intractable epilepsy, compared with adult epilepsy. To assess the role of each presurgical evaluation modality and to identify prognostic factors for favorable seizure control after epilepsy surgery, 38 children with intractable epilepsy who underwent surgery were retrospectively reviewed. Among the available preoperative evaluation modalities, PET and neuropsychological testing showed the highest rates of positive results, whereas MRI was the most concordant with EEG findings. During a follow-up period of at least 12 months, 26 of the 38 patients showed favorable seizure control (Engel classifications I and II). The best seizure control was achieved in patients with a temporal resection and discrete lesion on magnetic resonance imaging. In spite of the invasive study, the less satisfactory results followed an extratemporal resection. We conclude that epilepsy surgery benefits children with intractable epilepsy and that the role of invasive study should be reestablished according to the area of resection and presence of discrete lesion on MRI.

Role of P-glycoprotein in restricting propranolol transport in cultured rabbit conjunctival epithelial cell layers

PURPOSE

To determine the role of P-glycoprotein (P-gp) in propranolol transport in cultured rabbit conjunctival epithelial cell layers (RCEC).

METHODS

The localization of P-gp in the cultured RCEC as well as in the excised conjunctiva was determined by immunofluorescence technique. The role of P-gp in transepithelial transport and uptake of propranolol in conjunctival epithelial cells cultured on Transwell filters was evaluated in the presence and absence of P-gp competing substrates, an anti-P-gp monoclonal antibody (4E3 mAb), or a metabolic inhibitor, 2,4-dinitrophenol (2,4-DNP).

RESULTS

Immunofluorescence studies revealed positive staining in the apical membrane of cultured RCEC and in the apical surface of the superficial cell layers in the excised conjunctiva, but not the basolateral membrane of cultured RCEC. Transport of propranolol showed preference in the basolateral-to-apical direction. The net secretory flux was saturable with a Km of 71.5 +/- 24.0 nM and a Jmax of 1.45 +/- 0.17 pmol/cm2/hr. Cyclosporin A, progesterone, rhodamine 123, verapamil, 4E3 mAb and 2,4-DNP all increased apical 50 nM propranolol uptake by 43% to 66%. On the other hand, neither beta-blockers (atenolol, metoprolol, and alprenolol) nor organic cation transporter substrates (tetraethylammonium (TEA) and guanidine), affected apical 50 nM propranolol uptake.

CONCLUSIONS

The energy-dependent efflux pump P-gp appears to be predominantly located on the apical plasma membrane of the conjunctival epithelium. It may play an important role in restricting the conjunctival absorption of some lipophilic drugs.

Anti-promotion effect of chlorophyllin in DMBA-TPA-induced mouse skin carcinogenesis

This study aimed to elucidate the inhibitory effects of chlorophyllin (CHL) at different promotion stages in a DMBA-TPA-induced mouse skin carcinogenesis model. TPA promotion was undertaken for 6, 18 and 24 weeks, respectively. Proliferating activity was observed immunohistochemically and the ornithine decarboxylase (ODC) mRNA level was analyzed by reverse transcriptase-polymerase chain reaction. Messenger RNAs for c-fos, c-jun and jun-B were also observed. CHL treatment clearly reduced proliferating activity and the level of ODC mRNA at the 18-week-promotion stage. When promoted for 24 weeks, CHL was not effective in reducing proliferating activity and ODC mRNA expression. These results indicate that the promotion stage of each target tissue should be considered in a chemopreventive program.

Dedifferentiation of conditionally immortalized hepatocytes with long-term in vitro passage

The rat hepatocytes were immortalized using a temperature-sensitive mutant of SV40 large T antigen (tsT) to develop as a possible substitute for primary hepatocytes. Four rat hepatocyte lines that have been developed and maintained more than passage 50, were characterized for their cellular morphology, T antigen and p53 expression, chromosomes, liver-specific differentiation, telomerase activity and anchorage independent growth. All of four cell lines showed a typical epithelial cell morphology, but the population-doubling time became short with passage: 18 to 60%. T antigen expression was increased with passage about 3 to 65 times at permissive temperature but decreased significantly at non-permissive temperature. The expression level of p53 unchanged during passages was also decreased at non-permissive temperature. The distribution of chromosome number changed somewhat with passage. The production levels of albumin and urea in four cell lines were 2.4 to 13.0% and 7.5 to 19.9% of those produced in primary hepatocytes, respectively and were decreased to an undetectable level with passage. Telomerase activity was increased 10 fold following immortalization of cells, but anchorage independent growth of cells did not develop. These results indicate that conditionally immortalized hepatocytes become dedifferentiated with in vitro passage, which may be caused by marked chromosomal damages that occur with compulsive and continuous replications by the increment of T antigen content with passage and its sequential inhibition of p53 function.

Oxidative stress disrupts glucocorticoid hormone-dependent transcription of the amiloride-sensitive epithelial sodium channel alpha-subunit in lung epithelial cells through ERK-dependent and thioredoxin-sensitive pathways

The amiloride-sensitive epithelial Na(+) channel (ENaC) plays a critical role in the maintenance of alveolar fluid balance. It is generally accepted that reactive oxygen and nitrogen species can inhibit ENaC activity and aggravate acute lung injury; however, the molecular mechanism for free radical-mediated ENaC inhibition is unclear. Previously, we showed that the expression of the alpha-subunit of ENaC, alpha-ENaC, which is indispensable for ENaC activity, is repressed by Ras activation in salivary epithelial cells. Here, we investigated whether exogenous H(2)O(2) modulates alpha-ENaC gene expression in lung epithelial cells through a similar molecular mechanism. Utilizing transient transfection reporter assays and site-directed mutagenesis analyses, we found that the glucocorticoid response element (GRE), located at -1334 to -1306 base pairs of the alpha-ENaC 5'-flanking region, is the major enhancer for the stimulated alpha-ENaC expression in A549 lung epithelial cells. We further demonstrate that the presence of an intact GRE is necessary and sufficient for oxidants to repress alpha-ENaC expression. Consistent with our hypothesis, exogenous H(2)O(2)-mediated repression of alpha-ENaC GRE activity is partially blocked by either a specific inhibitor for extracellular signal-regulated kinase (ERK) pathway activation, U0126, or dominant negative ERK, suggesting that, in part, activated ERK may mediate the repressive effects of H(2)O(2) on alpha-ENaC expression. In addition, overexpression of thioredoxin restored glucocorticoid receptor action on the alpha-ENaC GRE in the presence of exogenous H(2)O(2). Taken together, we hypothesize that oxidative stress impairs Na(+) transport activity by inhibiting dexamethasone-dependent alpha-ENaC GRE activation via both ERK-dependent and thioredoxin-sensitive pathways. These results suggest a putative mechanism whereby cellular redox potentials modulate the glucocorticoid receptor/dexamethasone effect on alpha-ENaC expression in lung and other tight epithelia.

Functional characterization of organic cation drug transport in the pigmented rabbit conjunctiva

PURPOSE

To characterize carrier-mediated organic cation drug transport in the rabbit conjunctiva.

METHODS

The transport of [14C]guanidine, the model substrate, in the excised pigmented rabbit conjunctiva was evaluated in the modified Ussing chamber. Tetraethylammonium (TEA) transport also was investigated to determine substrate specificity.

RESULTS

The apparent permeability coefficient for guanidine and TEA in the mucosal-to-serosal (ms) direction was 5.4 and 49.6 times greater than that in the serosal-to-mucosal (sm) direction, respectively. Guanidine transport in the ms (but not sm) direction revealed temperature and concentration dependency over 0.02 to 10 mM with an apparent Michaelis-Menten constant of 3.1 mM and a maximal flux of 11.4 nmol/(cm2 x h). Net guanidine transport measured at 0.1 mM across the conjunctiva was decreased by 71% or 82%, respectively, on the addition of 1 microM valinomycin (a K+ ionophore) in both bathing fluids or in a high K+ buffer in the mucosal fluid. Interestingly, net guanidine transport was reduced, rather than enhanced, by 63% upon acidifying the mucosal bathing fluid. By contrast, net guanidine transport was not affected by the serosal presence of 0.5 mM ouabain (a Na+, K+-ATPase inhibitor), by the mucosal and serosal presence of 0.1 microM monensin (a Na+ ionophore) or 0.3 microM carbonyl cyanide p-(trifluoromethoxy)phenyl-hydrazone (FCCP, a H+ ionophore). Guanidine transport in the ms direction was polyspecific, as indicated by the 48% to 82% inhibition by structurally diverse amines. In particular, guanidine ms transport was inhibited by the antiglaucoma drugs dipivefrine (72%), brimonidine (70%), and carbachol (78%).

CONCLUSIONS

A carrier-mediated organic cation transport process appears to exist in the conjunctiva, mediating the absorption of organic amines, including certain amine-type ophthalmic drugs. This process may be driven by an inside-negative apical membrane potential difference.

GSH transport in human cerebrovascular endothelial cells and human astrocytes: evidence for luminal localization of Na+-dependent GSH transport in HCEC

The purpose of the present study was to identify and localize glutathione (GSH) transport in an in vitro tissue culture model of blood-brain barrier (BBB). The localization of Na+-dependent GSH transport in an immortalized cell line of human cerebrovascular endothelial cells (HCEC) and asymmetry of transport in Transwell studies were investigated. Initial studies with cultured HCEC established a significant (45%) Na+-dependency for GSH uptake in cultured HCEC pretreated with acivicin, an inhibitor of gamma-glutamyltranspeptidase (GGT). Transendothelial electrical resistance (TEER) and uptake of [35S]GSH from luminal and abluminal fluids of HCEC were measured in Na+-containing and Na+-free (choline chloride) buffers using cells grown on gelatin-coated membrane filters. TEER of HCEC monolayers in regular medium was 40.1 +/- 8.0 ohms cm2. Human astrocyte-conditioned medium (ACM) caused no change in TEER, but increased GGT activity approximately threefold when measured in cell lysates. Luminal and abluminal GSH uptake increased in a time-dependent fashion and were not affected by inhibition of GGT activity with acivicin. Sodium dependency was only observed for luminal uptake (Na+-containing 2.41 +/- 0.15 vs. Na+-free 0.96 +/- 0.03 pmol/30 min/million cells, p < 0.001) but not for abluminal uptake (1.02 +/- 0.13 vs. 1.11 +/- 09, p > 0.05). Apparent efflux via the luminal membrane was lower in the presence of sodium as compared to that without sodium, further suggesting that a Na+-dependent uptake process for GSH is operative at this membrane. GSH uptake and efflux were also demonstrated in neonatal rat and fetal human astrocytes, both exhibiting partial Na+-dependency of uptake. In conclusion, our results show for the first time, that HCEC and astrocytes take up GSH by both Na+-dependent and -independent mechanisms. The Na+-dependent GSH transport process in HCEC appears to be localized to luminal plasma membranes of HCEC.

Generalized interframe vertex-based shape encoding scheme for video sequences

The efficiency of shape coding is an important problem concerning content-based image manipulations and object-based coding of the video sequences. In order to encode the shape information of an object, the boundary is approximated by a polygon which can be encoded with the smallest number of bits for maximum allowable distortion. The conventional boundary coding schemes, however, does not successfully remove the temporal redundancy of the video sequences. This paper proposes a new boundary encoding scheme by which the temporal redundancy between two successive frames is efficiently removed, resulting in lower bit-rate than the conventional algorithms. The interframe vertex selection problem is solved by finding the path with the minimum cost in the directed acyclic graph (DAG) and its fast version using a simplified graph is introduced to reduce the computational load. The vertices were selected from both the current frame to be encoded and the previous frame already encoded, and thus, the temporal redundancy was effectively removed.

Complete genomic screen for disease susceptibility loci in nuclear families

We performed genome-wide model dependent and independent analyses on a simulated data set of 400 families segregating for a rare disorder. Regions on chromosomes 1, 3, and 5 were consistently indicated across the various analyses performed. Follow-up analyses included stratification for locus heterogeneity and clinical phenotype and studies of gene x gene and gene x environment interaction. The region around D1G024 was most notable, showing strong association and linkage with the trait. We also identified regions D3G043-46 and D5G037-39 by strong linkage and association findings and region D1G001-09 by linkage analysis. A complex statistical interaction was suggested between D1G024, D3G046 and environmental factor 1. This report suggests that traditional methods of analysis can be implemented to analyze and describe the mechanisms that may underlie the more complex genetic disorders.

Epidermal growth factor regulation in adult rat alveolar type II cells of amiloride-sensitive cation channels

Using the patch-clamp technique, we studied the effects of epidermal growth factor (EGF) on whole cell and single channel currents in adult rat alveolar epithelial type II cells in primary culture in the presence or absence of EGF for 48 h. In symmetrical sodium isethionate solutions, EGF exposure caused a significant increase in the type II cell whole cell conductance. Amiloride (10 microM) produced approximately 20-30% inhibition of the whole cell conductance in both the presence and absence of EGF, such that EGF caused the magnitude of the amiloride-sensitive component to more than double. Northern analysis showed that alpha-, beta- and gamma-subunits of rat epithelial Na(+) channel (rENaC) steady-state mRNA levels were all significantly decreased by EGF. At the single channel level, all active inside-out patches demonstrated only 25-pS channels that were amiloride sensitive and relatively nonselective for cations (P(Na(+))/P(K(+)) approximately 1.0:0.48). Although the biophysical characteristics (conductance, open-state probability, and selectivity) of the channels from EGF-treated and untreated cells were essentially identical, channel density was increased by EGF; the modal channel per patch was increased from 1 to 2. These findings indicate that EGF increases expression of nonselective, amiloride-sensitive cation channels in adult alveolar epithelial type II cells. The contribution of rENaC to the total EGF-dependent cation current under these conditions is quantitatively less important than that of the nonselective cation channels in these cells.

Modulation of brain mitochondrial membrane permeability and synaptosomal Ca2+ transport by dopamine oxidation

Effects of dopamine on the membrane permeability transition, thioredoxin reductase activity, production of free radicals and oxidation of sulfhydryl groups in brain mitochondria and the Ca2+ uptake by Na+-Ca2+ exchange and sulfhydryl oxidation in brain synaptosomes were examined. The brain mitochondrial swelling and the fall of transmembrane potential were altered by pretreatment of dopamine in a dose dependent manner. Depressive effect of dopamine on mitochondrial swelling was reversed by 10 microg/ml catalase, and 10 mM DMSO. The activities of thioredoxin reductase in intact or disrupted mitochondria were decreased by dopamine (1-100 microM), 25 microM Zn2+ and 50 microM Mn2+. Dopamine-inhibited enzyme activity was reversed by 10 microg/ml SOD and 10 microg/ml catalase. Pretreatment of dopamine decreased Ca2+ transport in synaptosomes, which was restored by 10 microg/ml SOD and 10 mM DMSO. Dopamine (1-100 microM) in the medium containing mitochondria produced superoxide anion and hydrogen peroxide, while its effect on nitrite production was very weak. The oxidation of sulfhydryl groups in mitochondria and synaptosomes were enhanced by dopamine with increasing incubation times. Results suggest that dopamine could modulate membrane permeability in mitochondria and calcium transport at nerve terminals, which may be ascribed to the action of free radicals and the loss of reduced sulfhydryl groups.

Nucleotide stimulation of Cl(-) secretion in the pigmented rabbit conjunctiva

We evaluated the role of extracellular UTP and other nucleotides in the regulation of active ion transport across the pigmented rabbit conjunctiva. When added to the mucosal side of the conjunctiva, UTP (0.01-1000 microM), increased the short-circuit current by up to 14. 6 +/- 2.1 microA/cm(2). The half-maximal concentration was 11.4 +/- 2.3 microM. The serosal absence of Cl(-), serosal presence of 10 microM bumetanide, and mucosal presence of 0.3 mM N-phenylanthranilic acid significantly reduced the change in the short-circuit current (DeltaIsc) induced by 10 microM UTP by 78, 77, and 42%, respectively. Mucosal 10 microM UTP significantly increased (36)Cl flux in the serosal-to-mucosal direction by 0.17 microEq/cm(2)/h, while not affecting mucosal-to-serosal (36)Cl flux. By contrast, (22)Na transport in either direction was unaffected. The rank order of DeltaIsc elicited by adenosine and nucleotides was consistent with the predominant involvement of P2Y purinergic receptors in the UTP effect on conjunctival ion transport. Moreover, the DeltaIsc elicited by UTP was inhibited by 0.05 and 1 mM suramin (a P2-purinergic receptor antagonist), resulting in a rightward shift of the half-maximal concentration to 106.7 +/- 1.3 microM. In conclusion, the primary effect of UTP on ion transport in the pigmented rabbit conjunctiva is stimulation of Cl(-) secretion, possibly at the P2Y(2) and/or the P2Y(4) receptor on the mucosal side of the tissue. Because of the coupling of fluid flow with Cl(-) secretion, UTP or its analogs may be considered for stimulating transconjunctival fluid flow in the dry-eye state.

Co-administration of toluene and xylene antagonized the testicular toxicity but not the hematopoietic toxicity caused by ethylene glycol monoethyl ether in Sprague-Dawley rats

Occupational painters are exposed to ethylene glycol monoethyl ether (EGEE), a widely used emulsifying solvent known to cause testicular degeneration and bone marrow depression, together with toluene (TOL) and xylene (XYL) as a mixture. In the previous study (Chung et al., Tox. Lett. 104:143, 1999), testicular atrophy caused by EGEE (200 mg/kg) was shown to be antagonized by co-administration of TOL (250 mg/kg) and XYL (500 mg/kg). This study was conducted to provide histological support for the previously observed antagonistic protective effect of TOL + XYL on EGEE inducible testicular toxicity and to determine whether a similar antagonistic effect can be demonstrated against the EGEE derived hematopoietic toxicity. Compared to the extent of seminiferous tubule degeneration caused by EGEE (150 mg/kg, six times per week for 4 weeks), testes of rats given co-administration of TOL (250 mg/kg) + XYL (500 mg/kg) showed dramatically reduced tubular degeneration. Hyperplasia of Leydig cells in the interstitium was observed in both EGEE and EGEE + TOL + XYL-treated rats. Although a minimal dose of EGEE causing testicular atrophy was used, WBC and platelet counts were decreased significantly. In the TOL + XYL-treated control group, the WBC and platelet counts were not decreased. However, the bone marrow depression caused by EGEE was not reversed by the combined administration of TOL + XYL. In all experimental groups (EGEE alone, TOL + XYL, EGEE + TOL + XYL), plasma levels of creatinine and alkaline phosphatase were significantly decreased. In addition to the marked testicular atrophy, EGEE also decreased the weights of adrenal glands and epididymis. In conclusion, while the testicular degeneration caused by EGEE was antagonized by TOL + XYL, the EGEE derived hematopoietic suppression was not reversed.

Staphylococcus lugdunensis--a potential pathogen in oral infection

OBJECTIVE

The purpose of this study was to investigate the pathogenicity of Staphylococcus lugdunensis in acute oral infection.

STUDY DESIGN

S. lugdunensis was isolated from patients with acute oral infections and from healthy control subjects. Antibiotic susceptibility, in vitro cellular toxicity, in vivo virulence, and hemolytic activity testing and dot blot analysis were performed. The statistical significance of in vitro cellular toxicity was determined by means of analysis of variance.

RESULTS

Isolated from the infected patients, S. lugdunensis showed resistance to penicillin, ampicillin, methicillin, cephalothin, and clindamycin, exhibited virulence in vivo, and showed delta-like hemolysin activity. Four of the 6 strains of S. lugdunensis gave synergistic hemolysis. In dot blot analysis, S. lugdunensis showed a positive reaction to the probe of the delta-hemolysin gene in S. aureus.

CONCLUSIONS

The results suggest that S. lugdunensis may be a potential pathogen in acute oral infection.

More characters or more taxa for a robust phylogeny--case study from the coffee family (Rubiaceae)

Using different data sets mainly from the plant family Rubiaceae, but in parts also from the Apocynaceae, Asteraceae, Lardizabalaceae, Saxifragaceae, and Solanaceae, we have investigated the effect of number of characters, number of taxa, and kind of data on bootstrap values within phylogenetic trees. The percentage of supported nodes within a tree is positively correlated with the number of characters, and negatively correlated with the number of taxa. The morphological analyses are based on few characters and weakly supported trees are expected. The percentage of supported nodes is also dependent on the kind of data analyzed. In analyses of Rubiaceae based on the same number of characters, RFLP data give trees with higher percentage of supported nodes than rbcL and morphological data. We also discuss the support values for particular nodes at the familial and subfamilial levels. Two new data sets of ndhF and rbcL sequences of Rubiaceae are analyzed and together with earlier studies of the family we can conclude that the monophyly of the Rubiaceae is supported and within the family there are three well supported, but not easily characterized, large subfamilies, Rubioideae, Cinchonoideae s.s. and Ixoroideae s.l. There are also a few genera (Luculia and Coptosapelta) unclassified to subfamily.

Organic cation transport in rabbit alveolar epithelial cell monolayers

PURPOSE

To characterize organic cation (OC) transport in primary cultured rabbit alveolar epithelial cell monolayers, using [14C]-guanidine as a model substrate.

METHODS

Type II alveolar epithelial cells from the rabbit lung were isolated by elastase digestion and cultured on permeable filters precoated with fibronectin and collagen. Uptake and transport studies of [14C]-guanidine were conducted in cell monolayers of 5 to 6 days in culture.

RESULTS

The cultured alveolar epithelial cell monolayers exhibited the characteristics of a tight barrier. [14C]-Guanidine uptake was temperature dependent, saturable, and inhibited by OC compounds such as amiloride, cimetidine, clonidine, procainamide, propranolol, tetraethylammonium, and verapamil. Apical guanidine uptake (Km = 129 +/- 41 microM, Vmax = 718 +/- 72 pmol/mg protein/5 min) was kinetically different from basolateral uptake (Km = 580 +/- 125 microM, Vmax = 1,600 +/- 160 pmol/mg protein/5 min). [14C]-Guanidine transport across the alveolar epithelial cell monolayer in the apical to basolateral direction revealed a permeability coefficient (Papp) of (7.3 +/- 0.4) x 10(-7) cm/sec, about seven times higher than that for the paracellular marker [14C]-mannitol.

CONCLUSIONS

Our findings are consistent with the existence of carrier-mediated OC transport in cultured rabbit alveolar epithelial cells.

The gene expression of the amiloride-sensitive epithelial sodium channel alpha-subunit is regulated by antagonistic effects between glucocorticoid hormone and ras pathways in salivary epithelial cells

The functional expression of the amiloride-sensitive epithelial sodium channel (ENaC) in select epithelia is critical for maintaining electrolyte and fluid homeostasis. Although ENaC activity is strictly dependent upon its alpha-subunit expression, little is known about the molecular mechanisms by which cells modulate alpha-ENaC gene expression. Previously, we have shown that salivary alpha-ENaC expression is transcriptionally repressed by the activation of Raf/extracellular signal-regulated protein kinase pathway. Here, this work further investigates the molecular mechanism(s) by which alpha-ENaC expression is regulated in salivary epithelial Pa-4 cells. A region located between -1.5 and -1.0 kilobase pairs of the alpha-ENaC 5'-flanking region is demonstrated to be indispensable for the maximal and Ras-repressible reporter expression. Deletional analyses using heterologous promoter constructs reveal that a DNA sequence between -1355 and -1269 base pairs functions as an enhancer conferring the high level of expression on reporter constructs, and this induction effect is inhibited by Ras pathway activation. Mutational analyses indicate that full induction and Ras-mediated repression require a glucocorticoid response element (GRE) located between -1323 and -1309 base pairs. The identified alpha-ENaC GRE encompassing sequence (-1334/-1306) is sufficient to confer glucocorticoid receptor/dexamethasone-dependent and Ras-repressible expression on both heterologous and homologous promoters. This report demon- strates for the first time that the cross-talk between glucocorticoid receptor and Ras/extracellular signal-regulated protein kinase signaling pathways results in an antagonistic effect at the transcriptional level to modulate alpha-ENaC expression through the identified GRE. In summary, this study presents a mechanism by which alpha-ENaC expression is regulated in salivary epithelial cells.

A cross-sectional study comparing the nutritional status of peritoneal dialysis and hemodialysis patients in Korea

OBJECTIVE

This study was performed to compare the nutritional status of peritoneal dialysis (PD) and hemodialysis (HD) patients in Korea and to validate the nutritional assessment method.

DESIGN

For nutritional assessment, we used five nutrition-related indicators, including percentage unplanned weight loss, percentage ideal body weight (IBW), serum albumin, appetite and intake, and any gastrointestinal symptoms affecting intake. A 1-month food frequency interview was conducted by clinical dietitians using food models to estimate energy and protein intake. The validity of the nutritional assessment method was tested by objective measures.

PATIENTS/SETTING

A cross-sectional study was conducted in our center for 51 PD patients and 169 HD patients who met the study criteria. In the study, HD patients typically underwent dialysis three times per week, and most PD patients performed four 2-L dialysis exchanges every day.

RESULTS

Our data showed a higher incidence of malnutrition in PD patients than in HD patients (33% v 18%) and in diabetics than in nondiabetics. Age, height, and dietary energy intake of the two groups were comparable. In PD patients, however, duration of dialysis treatment (23.9 +/- 19.1 months v 41.8 +/- 31.7 months, P < 0.001) and serum albumin (35.2 +/- 5.0 g/L v 39. 7 +/- 3.4 g/L, P < 0.0001) were significantly lower, whereas percentage IBW (108.1% +/- 12.4% v 96.2% +/- 11.6%, P < 0.0001) and dietary protein intake (1.12 +/- 0.34 g/kg IBW v 0.98 +/- 0.31 g/kg IBW, P < 0.05) were significantly higher than in HD patients. In malnourished PD and HD patients, percentage IBW, serum albumin, dietary energy, and protein intake were significantly lower than in well-nourished counterparts.

CONCLUSION

A higher incidence of malnutrition was observed in PD patients than in HD patients. Nutritional profile of PD patients was different from that of HD patients. Higher body weight and lower serum albumin in PD patients did not seem to be related to dietary energy and protein intake. The five nutritional indicators can be used as a simple inexpensive and reliable method for the early detection of malnutrition in dialysis patients.

Abnormal glutathione transport in cystic fibrosis airway epithelia

Glutathione (GSH) is a potentially important component of antioxidant defense in the epithelial lung lining fluid. Cystic fibrosis (CF) patients have chronic inflammation in which oxidative stress can be a factor. To examine the hypothesis that the transport of GSH content was defective in CF patients, intracellular and extracellular GSH were measured by HPLC. Four cell lines were used: CFT1 cells [with defective CF transmembrane conductance regulator (CFTR), DeltaF508 homozygous, two clones] and one of the CFT1 clones transfected with either normal CFTR (CFTR repleted) or beta-galactosidase. GSH content in the apical fluid was 55% lower in CFTR-deficient cultures than in CFTR-repleted cells (P < 0.001). In contrast, intracellular GSH content was similar in CFT1 cells and CFTR-repleted cells. gamma-Glutamyl transpeptidase activity, which degrades extracellular GSH, did not account for differences in apical GSH. Rather, GSH efflux of CFTR-deficient cells was lower than that of CFTR-repleted cells. These studies suggested that decreased GSH content in the apical fluid in CF resulted from abnormal GSH transport associated with a defective CFTR.

KGF prevents hyperoxia-induced reduction of active ion transport in alveolar epithelial cells

We evaluated the effects of acute hyperoxic exposure on alveolar epithelial cell (AEC) active ion transport and on expression of Na+ pump (Na+-K+-ATPase) and rat epithelial Na+ channel subunits. Rat AEC were cultivated in minimal defined serum-free medium (MDSF) on polycarbonate filters. Beginning on day 5, confluent monolayers were exposed to either 95% air-5% CO2 (normoxia) or 95% O2-5% CO2 (hyperoxia) for 48 h. Transepithelial resistance (Rt) and short-circuit current (Isc) were determined before and after exposure. Na+ channel alpha-, beta-, and gamma-subunit and Na+-K+-ATPase alpha1- and beta1-subunit mRNA levels were quantified by Northern analysis. Na+ pump alpha1- and beta1-subunit protein abundance was quantified by Western blotting. After hyperoxic exposure, Isc across AEC monolayers decreased by approximately 60% at 48 h relative to monolayers maintained under normoxic conditions. Na+ channel beta-subunit mRNA expression was reduced by hyperoxia, whereas alpha- and gamma-subunit mRNA expression was unchanged. Na+ pump alpha1-subunit mRNA was unchanged, whereas beta1-subunit mRNA was decreased approximately 80% by hyperoxia in parallel with a reduction in beta1-subunit protein. Because keratinocyte growth factor (KGF) has recently been shown to upregulate AEC active ion transport and expression of Na+-K+-ATPase under normoxic conditions, we assessed the ability of KGF to prevent hyperoxia-induced changes in active ion transport by supplementing medium with KGF (10 ng/ml) from day 2. The presence of KGF prevented the effects of hyperoxia on ion transport (as measured by Isc) relative to normoxic controls. Levels of beta1 mRNA and protein were relatively preserved in monolayers maintained in MDSF and KGF compared with those cultivated in MDSF alone. These results indicate that AEC net active ion transport is decreased after 48 h of hyperoxia, likely as a result of a decrease in the number of functional Na+ pumps per cell. KGF largely prevents this decrease in active ion transport, at least in part, by preserving Na+ pump expression.

Monolayers of human alveolar epithelial cells in primary culture for pulmonary absorption and transport studies

PURPOSE

To develop a cell culture model of human alveolar epithelial cells in primary culture for the in vitro study of pulmonary absorption and transport.

METHODS

Type II pneumocytes isolated from normal human distal lung tissue by enzyme treatment and subsequent purification were plated on fibronectin/collagen coated polyester filter inserts, and cultured using a low-serum growth medium. Characterization of the cell culture was achieved by bioelectric measurements, cell-specific lectin binding, immunohistochemical detection of cell junctions, and by assessment of transepithelial transport of dextrans of varying molecular weights.

RESULTS

In culture, the isolated cells spread into confluent monolayers, exhibiting peak transepithelial resistance of 2,180 +/- 62 ohms x cm2 and potential difference of 13.5 +/- 1.0 mV (n = 30-48), and developing tight junctions as well as desmosomes. As assessed by lectin-binding, the cell monolayers consisted of mainly type I cells with some interspersed type II cells, thus well mimicking the situation in vivo. The permeability of hydrophilic macromolecular FITC-dextrans across the cell monolayer was found to be inversely related to their molecular size, with Papp values ranging from 1.7 to 0.2 x 10(-8) cm/sec.

CONCLUSIONS

A primary cell culture model of human alveolar epithelial cells has been established, which appears to be a valuable in vitro model for pulmonary drug delivery and transport studies.

Neutralizing anti-vascular endothelial growth factor antibody inhibits further growth of established prostate cancer and metastases in a pre-clinical model

PURPOSE

The formation of new blood vessels from the pre-existing vasculature is necessary for support of primary tumor growth and appears coincident with the development of metastasis. In previous studies, inhibition of vascular endothelial growth factor (VEGF), a potent angiogenic factor and mediator of vascular permeability, inhibited tumor neovascularization with consequent inhibition of both primary tumor growth and micrometastases when administered at the time of tumor inoculation. In the present study, we examined the effect of inhibiting VEGF on primary tumor growth and metastases in an in vivo model of established metastatic prostate cancer.

MATERIALS AND METHODS

The human prostate cancer cell line DU-145 was found to secrete VEGF. DU-145.luciferase, a subclone stably transfected with an expression vector encoding the luciferase gene, injected subcutaneously, consistently formed tumors in C.B.-17 scid/scid mice. After 6 weeks, assay of whole lung lysates showed significant luciferase activity, consistent with the presence of micrometastasis.

RESULTS

Twice weekly treatment of the animals with a monoclonal anti-VEGF neutralizing antibody, A4.6.1, not only suppressed primary tumor growth, but inhibited metastatic dissemination to the lung. When treatment was delayed until the primary tumors were well-established, further growth was still inhibited, as was the progression of metastatic disease.

CONCLUSION

Inhibition of tumor-secreted VEGF by a neutralizing antibody is sufficient to significantly impair prostate tumor growth and its subsequent metastasis in an in vivo model of established advanced prostate cancer. These data suggest a critical role for VEGF in initiation and maintenance of tumor angiogenesis in prostate cancer. Inhibition of VEGF in patients with VEGF-secreting prostate cancers may prove an effective approach for inhibiting disease progression even after micro-metastatic dissemination has occurred.

Adaptive approximation bounds for vertex based contour encoding

When approximating the shape of a region, a fixed bound on the tolerable distortion is set for approximating its contour points. An adaptive approximation bound for lossy coding of the contour points is proposed. A function representing the relative significance of the contour points is defined to adjust the distortion bound along the region contour allowing an adaptive approximation of the region shape. The effectiveness of the adaptive contour coding approach for a region-based coding system is verified through experiments.

The amiloride-sensitive epithelial sodium channel alpha-subunit is transcriptionally down-regulated in rat parotid cells by the extracellular signal-regulated protein kinase pathway

Previous studies have shown that an inducible Raf-1 kinase protein, DeltaRaf-1:ER, activates the mitogen-activated protein kinase/extracellular signal-regulated protein kinase (ERK)-signaling pathway, which is required for the transformation of the rat salivary epithelial cell line, Pa-4. Differential display polymerase chain reaction was employed to search for mRNAs repressed by DeltaRaf-1:ER activation. Through this approach, the gene encoding the alpha-subunit of the amiloride-sensitive epithelial sodium channel (alpha-ENaC) was identified as a target of activated Raf-1 kinases. alpha-ENaC down-regulation could also be seen in cells treated with 12-O-tetradecanoyl-1-phorbol-13-acetate (TPA), indicating that the repression of steady-state alpha-ENaC mRNA level was dependent upon the activity of protein kinase C, the target of TPA, as well. Pretreatment of cells with a specific inhibitor of the ERK kinase pathway, PD 98059, markedly abolished the down-regulation of alpha-ENaC expression, consistent with the hypothesis that the ERK kinase-signaling pathway is involved in TPA-mediated repression. Moreover, through the use of transient transfection assays with alpha-ENaC-reporter and activated Raf expression construct(s), we provide the first evidence that activation of the ERK pathway down-regulates alpha-ENaC expression at the transcriptional level. Elucidating the molecular programming that modulates the expression of the alpha-subunit may provide new insights into the modulation of sodium reabsorption across epithelia.

Structure, function, and molecular modeling approaches to the study of the intestinal dipeptide transporter PepT1

The proton-coupled intestinal dipeptide transporter, PepT1, has 707 amino acids, 12 putative transmembrane domains (TMD), and is of importance in the transport of nutritional di- and tripeptides and structurally related drugs, such as penicillins and cephalosporins. By using a combination of molecular modeling and site-directed mutagenesis, we have identified several key amino acid residues that effect catalytic transport properties of PepT1. Our molecular model of the transporter was examined by dividing it into four sections, parallel to the membrane, starting from the extracellular side. The molecular model revealed a putative transport channel and the approximate locations of several aromatic and charged amino acid residues that were selected as targets for mutagenesis. Wild type or mutagenized human PepT1 cDNA was transfected into human embryonic kidney (HEK293) cells, and the uptake of tritiated glycylsarcosine [3H]-(Gly-Sar) was measured. Michaelis-Menton analysis of the wild-type and mutated transporters revealed the following results for site-directed mutagenesis. Mutation of Tyr-12 or Arg-282 into alanine has only a very modest effect on Gly-Sar uptake. By contrast, mutation of Trp-294 or Glu-595 into alanine reduced Gly-Sar uptake by 80 and 95%, respectively, and mutation of Tyr-167 reduced Gly-Sar uptake to the level of mock-transfected cells. In addition, preliminary data from fluorescence microscopy following the expression of N-terminal-GFP-labeled PepT1Y167A in HEK cells indicates that the Y167A mutation was properly inserted into the plasma membrane but has a greatly reduced Vmax.

Involvement of APO2 ligand/TRAIL in activation-induced death of Jurkat and human peripheral blood T cells

The interaction of Fas with Fas ligand (FasL) mediates activation-induced cell death (AICD) of T hybridomas and of mature T lymphocytes. The TNF/TNF receptor system also plays a significant role in AICD of mature T cells and in the maintenance of peripheral tolerance. We previously demonstrated that in human Jurkat leukemia cells, AICD is triggered mainly by the rapid release of preformed FasL upon TCR stimulation. In the present work, we show that the cytotoxic cytokine APO2 ligand (APO2L; also known as TRAIL) is constitutively expressed as an intracytoplasmic protein in Jurkat T cells and derived sublines. APO2L is also detected in fresh human peripheral blood mononuclear cells (PBMC) from a significant number of donors, and the amount of both FasL and APO2L substantially increases upon blast generation. A neutralizing anti-APO2L monoclonal antibody (mAb) partially suppresses the cytotoxicity induced by supernatants of phytohemagglutinin (PHA)-prestimulated Jurkat or human PBMC on non-activated Jurkat cells, indicating that APO2L is released by these cells and contributes to AICD. A combination of neutralizing anti-APO2L and anti-Fas mAb blocks around 60 % of the toxicity associated with supernatants from PHA-activated human PBMC. These results show that FasL and APO2L account for the majority of cytotoxic activity released during AICD, and suggest that additional uncharacterized factors may also contribute to this process.

Involvement of APO2 ligand/TRAIL in activation-induced death of Jurkat and human peripheral blood T cells

The interaction of Fas with Fas ligand (FasL) mediates activation-induced cell death (AICD) of T hybridomas and of mature T lymphocytes. The TNF/TNF receptor system also plays a significant role in AICD of mature T cells and in the maintenance of peripheral tolerance. We previously demonstrated that in human Jurkat leukemia cells, AICD is triggered mainly by the rapid release of preformed FasL upon TCR stimulation. In the present work, we show that the cytotoxic cytokine APO2 ligand (APO2L; also known as TRAIL) is constitutively expressed as an intracytoplasmic protein in Jurkat T cells and derived sublines. APO2L is also detected in fresh human peripheral blood mononuclear cells (PBMC) from a significant number of donors, and the amount of both FasL and APO2L substantially increases upon blast generation. A neutralizing anti-APO2L monoclonal antibody (mAb) partially suppresses the cytotoxicity induced by supernatants of phytohemagglutinin (PHA)-prestimulated Jurkat or human PBMC on non-activated Jurkat cells, indicating that APO2L is released by these cells and contributes to AICD. A combination of neutralizing anti-APO2L and anti-Fas mAb blocks around 60 % of the toxicity associated with supernatants from PHA-activated human PBMC. These results show that FasL and APO2L account for the majority of cytotoxic activity released during AICD, and suggest that additional uncharacterized factors may also contribute to this process.

Molecular identification of a role for tyrosine 167 in the function of the human intestinal proton- coupled dipeptide transporter (hPepT1)

hPepT1 is a proton-coupled peptide transporter that mediates the absorption of di- and tripeptides. Here we show that tyrosine 167 (Y167) in transmembrane domain 5 (TMD5) of this 12-transmembrane spanning protein contributes to its transport function. We identified this particular amino acid by a computer model of the arrangement of the TMDs of hPepT1 and investigated its role by site-directed mutagenesis and dipeptide uptake studies. [3H]Gly-sar uptake in cells transiently transfected with Y167A-hPepT1 was abolished completely, even though the level of Y167A-hPepT1 expression by Western blot analysis and cell surface expression by immunofluorescence microscopy was similar to those of the wild type. Therefore, mutation affected transport function, but apparently not the steady-state protein level or trafficking of the transporter to the plasma membrane. Moreover, mutation of Y167 into phenylalanine, serine, or histidine all abolished gly-sar uptake in transfected HEK 293 cells. Taken together, these findings suggest that Y167 plays an essential role in hPepT1 function, perhaps due to the unique chemistry of its phenolic side chain.

A chloroplast DNA phylogeny of lilacs (Syringa, Oleaceae): plastome groups show a strong correlation with crossing groups

Phylogenetic relationships and genomic compatibility were compared for 60 accessions of Syringa using chloroplast DNA (cpDNA) and nuclear ribosomal DNA (rDNA) markers. A total of 669 cpDNA variants, 653 of which were potentially phylogenetically informative, was detected using 22 restriction enzymes. Phylogenetic analyses reveal four strongly supported plastome groups that correspond to four genetically incompatible crossing groups. Relationships of the four plastome groups (I(II(III,IV))) correlate well with the infrageneric classification except for ser. Syringa and Pinnatifoliae. Group I, which includes subg. Ligustrina, forms a basal lineage within Syringa. Group II includes ser. Syringa and Pinnatifoliae and the two series have high compatibility and low sequence divergence. Group III consists of three well-defined species groups of ser. Pubescentes. Group IV comprises all members of ser. Villosae and has the lowest interspecific cpDNA sequence divergences. Comparison of cpDNA sequence divergence with crossability data indicates that hybrids have not been successfully generated between species with divergence greater than 0.7%. Hybrid barriers are strong among the four major plastome groups, which have sequence divergence estimates ranging from 1.096 to 1.962%. In contrast, fully fertile hybrids occur between species pairs with sequence divergence below 0.4%. Three regions of the plastome have length variants of greater than 100 bp, and these indels identify 12 different plastome types that correlate with phylogenetic trees produced from cpDNA restriction site data. Biparentally inherited nuclear rDNA and maternally inherited cpDNA length variants enable the identification of the specific parentage of several lilac hybrids.

Involvement of APO2 ligand/TRAIL in activation-induced death of Jurkat and human peripheral blood T cells

The interaction of Fas with Fas ligand (FasL) mediates activation-induced cell death (AICD) of T hybridomas and of mature T lymphocytes. The TNF/TNF receptor system also plays a significant role in AICD of mature T cells and in the maintenance of peripheral tolerance. We previously demonstrated that in human Jurkat leukemia cells, AICD is triggered mainly by the rapid release of preformed FasL upon TCR stimulation. In the present work, we show that the cytotoxic cytokine APO2 ligand (APO2L; also known as TRAIL) is constitutively expressed as an intracytoplasmic protein in Jurkat T cells and derived sublines. APO2L is also detected in fresh human peripheral blood mononuclear cells (PBMC) from a significant number of donors, and the amount of both FasL and APO2L substantially increases upon blast generation. A neutralizing anti-APO2L monoclonal antibody (mAb) partially suppresses the cytotoxicity induced by supernatants of phytohemagglutinin (PHA)-prestimulated Jurkat or human PBMC on non-activated Jurkat cells, indicating that APO2L is released by these cells and contributes to AICD. A combination of neutralizing anti-APO2L and anti-Fas mAb blocks around 60 % of the toxicity associated with supernatants from PHA-activated human PBMC. These results show that FasL and APO2L account for the majority of cytotoxic activity released during AICD, and suggest that additional uncharacterized factors may also contribute to this process.

Principles of urodynamics pressure measurement and its implication to female continence function

Urodynamic pressure measurements using catheters have been widely used among clinicians. More often objective interpretation of urodynamic pressure measurements requires fundamental understanding of pressure measurement techniques due to many measurement artifacts. In this study we developed a simplified compound thick-walled cylinder model to investigate the mechanical nature of urodynamic pressure measurement as well as pressure transmission. Efficacy of collagen implantation was also explored. Lamé's formulation was used to find analytical solutions. Pressure transmission can be related to catheter caliber and the compressibility of the urethral tissue (poisson ratio) in a simple mathematical form. The theoretical pressure transmission ratio will be 133% with the additional incompressibility assumption, reflecting the passive structural transmission of intraabdominal pressure increase. The relationship between the pressure measurement error and the catheter caliber was found to be linear (r2 = 0.94 +/- 0.04) and two or more pressure measurements need to be used to find the uninstrumented pressure. It was predicted that collagen implantation treatment might improve the pressure transmission ratio maximally by 33%.

An instrumented wheel for kinetic analysis of wheelchair propulsion

An instrumented wheel system for three-dimensional kinetic analysis of upper extremity during wheelchair propulsion has been designed and validated. This system allows the direct measurements of three-dimensional dynamic forces and moments on the handrim during wheelchair propulsion in a laboratory setting as well as in the field. Static loading tests showed a high linearity and little drift (coefficient of determination, r2 > 0.999). Under dynamic loading, the instrumented wheel provided the well-matched measurement forces and moments with the predicted values from the inverse dynamic method using video-based kinematic data (correlation coefficient, p > 0.97). The three-dimensional handrim forces and moments during wheelchair propulsion by a non-disabled subject were demonstrated.

Dipeptide uptake and transport characteristics in rabbit tracheal epithelial cell layers cultured at an air interface

PURPOSE

To determine the functional presence ofa H+/peptide cotransport process in rabbit tracheal epithelial cell layers cultured at an air-interface and its contribution to transepithelial dipeptide transport.

METHODS

Rabbit tracheocytes were isolated, plated on Transwells, and cultured at an air-interface. After 5 or 6 days in culture, uptake and transepithelial transport of carnosine were examined.

RESULTS

Carnosine uptake by tracheocytes was pH-dependent and was saturable with a Michaelis-Menten constant of 170 microM. Moreover, carnosine uptake was inhibited 94% by Gly-L-Phe, 28% by beta-Ala-Gly, but not at all by Gly-D-Phe or by the amino acids beta-Ala and L-His. Unexpectedly. transepithelial carnosine transport at pH 7.4 (i.e., in the absence of a transepithelial pH gradient) was similar in both the apical-to-basolateral (ab) and basolateral-to-apical (ba) directions. Lowering the apical fluid pH to 6.5 reduced ab transport 1.6 times without affecting ba transport, consistent with predominantly paracellular diffusion of carnosine under an electrochemical potential gradient.

CONCLUSIONS

The kinetic behavior of carnosine uptake into cultured tracheal epithelial cell layers is characteristic of a H+-coupled dipeptide transport process known to exist in the small intestine and the kidney. Such a process does not appear to be rate-limiting in the transport of carnosine across the tracheal epithelial barrier.

Osteolysis model with continuous infusion of polyethylene particles

Several in vivo studies have investigated bone to implant interface tissues after a single injection of wear particles into animal joints. However, in the clinical setting, wear debris are generated continuously rather than periodically. Histomorphologic findings and the gene expression of bone resorbing cytokines in reactive membranes were analyzed in response to continuous infusion of polyethylene particles with an osmotic pump. In this model, it took only 6 weeks for proliferative fibrous tissue to form, which penetrated the subchondral bone to communicate with the bone marrow. In addition, tartrate resistant acid phosphatase positive osteoclastlike cells were found in empty lacunae. According to the analysis of gene expression, only tumor necrosis factor alpha messenger ribonucleic acid was expressed specifically in the fibrous tissue of rats infused with particles from 4 weeks after surgery. This finding suggests that tumor necrosis factor alpha may play a major role in fibrous tissue formation and osteoclastic bone resorption caused by wear debris around implants. In addition, this in vivo model seems useful for investigating the mechanism of membrane formation and associated bone resorption around implants in a situation more similar to human prostheses than in conventional models.

Carrier-mediated transport of monocarboxylate drugs in the pigmented rabbit conjunctiva

PURPOSE

To determine whether an Na+-dependent monocarboxylate transport process exists on the mucosal side of the pigmented rabbit conjunctiva and to evaluate how it may contribute to the absorption of ophthalmic monocarboxylate drugs.

METHODS

L-lactate was used as a model substrate. The excised pigmented rabbit conjunctiva was mounted in a modified Ussing chamber for the measurement of short-circuit current (Isc) and 14C-L.-lactate transport.

RESULTS

When added to the mucosal side at 37 degrees C and at pH 7.4, applications of as much as 40 mM L- and D-lactate increased Isc in a saturable manner. By contrast, no change in Isc was observed at 4 degrees C or under the mucosal Na+-free condition. 14C-L-lactate transport in the mucosal-to-serosal (m-s) direction at 0.01 mM revealed directionality, temperature dependency, Na+ dependency, and ouabain sensitivity, but not pH dependency. L-lactate transport in the m-s direction consisted of a saturable Na+-dependent process by the transcellular pathway and a nonsaturable process by the paracellular pathway. For the saturable process, the apparent Michaelis-Menten constant was 1.9 mM, the maximum flux was 8.9 nanomoles/cm2 per hour, and the apparent Na+ :L-lactate coupling ratio was 2:1. 14C-L-lactate transport in the m-s direction was significantly inhibited (46% to 83%) by the mucosal presence of various monocarboxylate compounds, but not by dicarboxylate compounds, zwitterionic compound, D-glucose, amino acids, and peptidomimetic antibiotics. Monocarboxylate nonsteroidal anti-inflammatory drugs and the antibacterial fluoroquinolones inhibited 14C-L-lactate transport by 40% to 85%, whereas prostaglandins and cromolyn had no effect.

CONCLUSIONS

An Na+-dependent monocarboxylate transport process that may be used by non-steroidal anti-inflammatory and fluoroquinolone antibacterial drugs for transport appears to be present on the mucosal side of the pigmented rabbit conjunctiva. A possible physiologic role for the Na+-dependent monocarboxylate transport process may be to salvage tear lactate.

(Ta/Si) multilayer as a wide-bandpass monochromator material

Specular and non-specular X-ray reflectivity intensities of a (Ta/Si)(60) multilayer sample were measured to characterize its interface structure. Since the multilayer has a good reflectance at its multilayer peaks, its performance as a wide-bandpass monochromator for X-ray scattering experiments of polymers has been tested.