Kinetic evidence for Na(+)-glucose co-transport in the pigmented rabbit conjunctiva

PURPOSE

To obtain kinetic evidence for the existence of a Na(+)-coupled glucose co-transport process on the mucosal (tear) side of the pigmented rabbit conjunctiva.

METHODS

The excised pigmented rabbit conjunctiva was mounted in the modified Ussing chamber for measurement of 22Na and 3H-3-O-methyl-D-glucose (3-O-MG) fluxes.

RESULTS

In the presence of 5 mM glucose, the conjunctival tissue showed net Na+ absorption in the mucosal-to-serosal direction at an approximate rate of 0.15 microEq/cm2/h. This net Na+ absorption was abolished by serosally added 0.5 mM ouabain, but not affected by mucosally added 0.1 mM or 1 mM amiloride. There was a 40-60% reduction in net Na+ absorption under the glucose-free condition or in the mucosal presence of 0.5 mM phlorizin. Moreover, serosally added ouabain and mucosally added phlorizin (both at 0.5 mM) significantly decreased the 3-O-MG permeability coefficient in the mucosal-to-serosal direction by about 70%, whereas mucosally instilled 0.1-1.0 mM amiloride was without any effect. Three-O-MG absorption in the mucosal-to-serosal direction appeared to be coupled with Na+ transport with a 1:1 stoichiometry. In addition, this process exhibited temperature dependency, saturability, and directionality.

CONCLUSION

Our findings are consistent with Na(+)-glucose cotransport as being one of the mechanisms for mucosal Na+ entry into the epithelial cells of the pigmented rabbit conjunctiva.

Na(+)-dependent L-arginine transport in the pigmented rabbit conjunctiva

The objective of this study was to characterize Na(+)-coupled L-arginine (L-Arg) transport in the pigmented rabbit conjunctiva. The excised pigmented rabbit conjunctiva was mounted in the modified Ussing chamber for measurement of short-circuit current (Isc), 3H-L-arginine (3H-L-Arg) flux, and 22Na flux. L-Arg when added to the mucosal side led to 0.32-2.65 microA cm-2 increases in the Isc at 37 degrees C, but not at 4 degrees C or in a Na(+)-free solution. L-Arg at 1 mM stimulated net Na+ absorption by 0.12 microEq cm-2 h-1. The evidence for carrier-mediated transport of L-Arg includes: (1) temperature dependence and saturability over 0.01-10 mM, (2) Na+ dependence and ouabain sensitivity, (3) 84 +/- 2% reduction in the apparent permeability coefficient (Papp) of 3H-L-Arg in the presence of excess unlabeled L-Arg (1 mM), and (4) 16-fold difference in L-Arg transport (at 0.1 mM) between the mucosal-to-serosal and the serosal-to-mucosal direction. Moreover, L-Arg transport was inhibited by basic amino acids, large neutral amino acids, and nitric oxide synthase inhibitors, but not by acidic and small neutral amino acids. Kinetic analysis revealed the possible existence of both high and low affinity processes for L-Arg transport. A half maximal concentration (Km) and maximal L-Arg flux (Jmax) values of the low and high affinity processes were 5.90 and 0.07 mM, and 1,248 and 111 pmol cm-2 min-1, respectively. Hill analysis of L-Arg transport at 0.1 mM in the presence of varying Na+ concentrations in the mucosal bathing fluid yielded a Hill coefficient of 0.93, suggesting a 1:1 coupling between Na+ and L-Arg. In conclusion, Na(+)-coupled transport process(es) for L-Arg in accordance with a 1:1 stoichiometry appear to be present on the mucosal side of the pigmented rabbit conjunctiva. The pattern of inhibition by basic and large neutral amino acids and Na+ dependency are suggestive of system B0,(+)-mediated L-Arg transport.

Changes in the alpha 2-adrenergic receptor subtypes gene expression in rat dorsal root ganglion in an experimental model of neuropathic pain

We examined changes in expression of genes coding for alpha 2-AR subtypes in the dorsal root ganglion (DRG) in a rat model (spinal nerve ligation) or neuropathic pain. The present study demonstrates that the majority of DRG neurons express alpha 2C-AR mRNA and a small proportion of neurons express alpha 2A-AR mRNA, while few neurons express alpha 2B-AR mRNA in non-operated animals. In addition, alpha 2C- and alpha 2A mRNA levels in the DRG showed a significant decrease and increase, respectively in ligated animals. These findings suggest that alpha 2A- and alpha 2C-ARs in the DRG may play an important role in generating sympathetically maintained neuropathic pain.

Blunt traumatic rupture of the diaphragm: sonographic diagnosis

Ultrasonographic features of seven patients with diaphragmatic rupture due to blunt trauma were analyzed. The ruptures occurred at the left hemidiaphragm in four patients and at the right in three. Direct ultrasonographic findings were as follows: disrupted diaphragm in four patients; nonvisualized diaphragm in three patients; floating diaphragm in two patients; and herniation of the liver or bowel loops through the diaphragmatic defect in three patients. Indirect sonographic findings included pleural effusion or subphrenic fluid collection in five patients and splenic laceration in one. Although the number of patients was limited, ultrasonography was very useful for the diagnosis of diaphragmatic rupture.

Polar solute transport across the pigmented rabbit conjunctiva: size dependence and the influence of 8-bromo cyclic adenosine monophosphate

PURPOSE

To characterize the conjunctival permeability to polar solutes ranging from 182 to 167,000 daltons in molecular weight (m.w.).

METHODS

Solute transport across the excised pigmented rabbit conjunctiva with a baseline transepithelial electrical resistance (TEER) of 1,285 +/- 46 ohm.cm2 was evaluated in the modified Ussing chamber under open-circuit conditions. The model solutes were mannitol (m.w. 182), 6-carboxyfluorescein (m.w. 376), and fluorescein isothiocyanate-labeled dextrans (FD4, m.w. 4,400-FD150, m.w. 167,000).

RESULTS

For a given solute, the apparent permeability coefficient (Papp) was independent of solute concentration and direction of transport. As expected, the Papp decreased with solute size, from 27.7 x 10(-8) cm/sec for mannitol to 0.31 x 10(-8) cm/sec for FD150. When the experimental temperature was lowered from 37 degrees C to 4 degrees C. Papp decreased by approximately 50% for FD4 through FD40 and by > 80% for both FD70 and FD150. Equivalent pore analysis, assuming restricted solute diffusion via cylindrical, water-filled pores across the isolated tissue, revealed a radius of 5.5 nm at a pore density of 1.9 x 10(8) pores per cm2. The addition of 1 mM 8-bromo cyclic adenosine monophosphate (8-BrcAMP), known to stimulate Cl- secretion and decrease TEER, to the mucosal side of the conjunctiva increased the transport of mannitol, FD4, and FD40 by 28%, while not affecting FD150 transport.

CONCLUSIONS

Our findings suggest that polar solutes up to FD40 traverse the conjunctival epithelial barrier primarily by restricted diffusion through equivalent pores of 5.5 nm radius and that solute movement is affected by reduction of TEER. On the other hand, polar solutes of the FD70 or larger may cross the barrier primarily via non-diffusional pathways such as non-specific endocytosis.

Effects of 'crack' cocaine on pulmonary alveolar permeability

BACKGROUND

Lung clearance of 99mTc-labeled diethylenetriamine pentaacetate (DTPA) is a sensitive test of altered alveolar epithelial permeability that has been found to be increased in smokers of tobacco, as well as a small number of healthy smokers of crack cocaine, suggesting the possibility of subclinical crack-related lung injury.

STUDY OBJECTIVE

To evaluate further whether habitual smoking of cocaine alone alters alveolar permeability, whether crack smoking adds to or potentiates the effects of tobacco and/or marijuana, and whether experimental cocaine smoking acutely alters DTPA lung clearance.

DESIGN

Observational cohort study (habitual cocaine smoking) and single-blind crossover study (experimental cocaine administration).

SUBJECTS

Fourteen habitual smokers of cocaine alone (CS), 19 smokers of cocaine and tobacco (CTS), 3 smokers of cocaine and marijuana, 12 smokers of cocaine, tobacco, and marijuana (CMTS), and 5 smokers of marijuana plus tobacco (MTS). Results obtained in the crack-smoking subjects were compared with data previously obtained in 10 nonsmokers (NS), 9 smokers of tobacco alone (TS), 10 smokers of marijuana alone (MS), and 4 additional MTS.

METHODS

Subjects underwent measurements of DTPA radioaerosol lung clearance after refraining from marijuana and/or cocaine for > 12 h and from tobacco for >2 h. Ten of the 48 crack users were tested on two days 1 to 2 weeks apart within 2 h of experimental smoking of three physiologically active or inactive doses (total 98.8+/-15.5 or 8.5+/-2.5 mg, respectively) of cocaine base. Lung clearance half-times (T1/2) were computed from time-activity curves for each lung.

RESULTS

T1/2 values for each lung in CS and MS were comparable to those of NS, while TS, MTS, CTS, and CMTS had significantly shorter clearance rates than NS (p<0.01; three-way analysis of variance). No additive or interactive effects on T1/2 were noted among tobacco, cocaine, and/or marijuana. No acute effect of experimental cocaine smoking on T1/2 was noted.

CONCLUSION

Whereas regular smoking of tobacco alone or with other substances increases alveolar epithelial permeability, habitual smoking of cocaine and/or marijuana has no measurable effect on alveolar permeability in the absence of tobacco nor any additive effect to that of tobacco alone.

Molecular analysis of hypoxanthine guanine phosphoribosyltransferase (HPRT) gene in five Korean families with Lesch-Nyhan syndrome

Lesch-Nyhan syndrome is caused by the complete deficiency of hypoxanthine guanine phosphoribosyl-transferase (HPRT). By the analysis of genomic DNA and mRNA using the polymerase chain reaction (PCR) technique coupled with direct sequencing, five independent mutations in HPRT genes have been identified in Korean Lesch-Nyhan families. Two novel mutations and three previously reported mutations have been found in five independent families. Heterozygous carriers were detected in all the families, and prenatal diagnosis was carried out in two families.

Renovascular hypertension in children with moyamoya disease

OBJECTIVES

To examine the incidence, clinical and radiologic findings, and response to treatment of renovascular hypertension (RVHT) in moyamoya disease (MMD).

METHODS

A retrospective analysis of medical records in six RVHT cases (8.3%) among 72 MMD patients observed from November 1987 to December 1995.

RESULTS

The age at onset of MMD ranged from 9 months to 7 years 1 month (mean, 3.3 years). The most common initial manifestation of MMD was transient ischemic attack. Hypertension was detected between 4 years 4 months and 12 years 3 months (mean, 7.87 years). Unstimulated plasma renin activity was elevated in all six cases. Renal ultrasonography and captopril technetium 99m-labeled dimercaptosuccinic acid scan showed abnormal findings in four of five and in three of four available studies, respectively. However, both imaging studies showed abnormal findings only in the most severely affected kidneys even with bilateral renal artery stenosis. Renal arteriography revealed bilateral lesions in three of the patients and unilateral lesions in the others. Renal angioplasty was performed in four cases but was successful in only one and partially successful in another. A renal artery specimen obtained during renal autotransplantation showed intimal fibroplasia. At the last follow-up, one patient had normal blood pressure without the use of antihypertensive agents, but the other five patients needed this medication to control blood pressure.

CONCLUSION

Because RVHT may be more commonly associated with MMD than has hitherto been appreciated, it is recommended that blood pressure be carefully followed and that diagnostic procedures for RVHT be carried out in hypertensive patients with MMD.

Phase Transformation Behavior at Low Temperature in Hydrothermal Treatment of Stable and Unstable Titania Sol

Nanosize titania sol was prepared from titanium tetraisopropoxide (TTIP) and conditions for the formation of stable sol were identified. As the H+/TTIP mole ratio decreased and H2O/TTIP mole ratio increased, stable sol was likely to be formed. The size and crystallinity remained unchanged after hydrothermal treatment of the stable sol at between 160 and 240&deg;C. However, hydrothermal treatment of unstable sol produced rod-like particles and crystallinity of particles was changed from anatase to rutile. This difference in phase transformation at low hydrothermal treatment temperature was likely to be caused by the fact that stable sol remained to be stable even after hydrothermal treatment, while unstable sol had a tendency to be aggregated.

Properties of biomolecules measured from atomic force microscope images: a review

AFM images can be used to obtain quantitative or qualitative information about the properties of biomaterials. Examples presented here are: (1) Persistence length measurements of moving and stationary DNA molecules. (2) Force mapping to measure properties such as the elasticity of cells and vesicles. (3) Phase mode imaging to detect variations in materials and properties of the sample surface. (4) Imaging of surfaces at different constant forces.

Effects of recombinant human bone morphogenetic protein-2 on human bone marrow cells cultured with various biomaterials

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is known to induce orthotopic and ectopic bone formation in vivo. Several in vitro studies using rat or mouse clonal cell lines have shown that rhBMP-2 may be involved in the differentiation of osteoblasts from osteoblast precursor cells or stromal cells in the bone marrow. However, there is little information available about the effects of rhBMP-2 on cultured human bone marrow cells. We investigated the effects of rhBMP-2 cultured on human bone marrow cells and osteoblastic cells on various biomaterials. Human bone cells were divided into fresh bone marrow cells, fibroblast colony-forming units (cfu-F, stromal precursors), and osteoblastic cells. The cells were cultured with or without rhBMP-2 on various biomaterials, including titanium alloy, pure titanium, cobalt alloy, and hydroxyapatite. It was found that rhBMP-2 (500 ng/mL) significantly stimulated alkaline phosphatase production by fresh bone marrow cells and cfu-F. However, when cultured on titanium alloy or pure titanium, only fresh bone marrow cells showed an increase of alkaline phosphatase production after rhBMP-2 stimulation. Production of osteocalcin, a marker of mature osteoblasts, was not stimulated by rhBMP-2 in any combinations tested. These findings suggest that rhBMP-2 may be involved in inducing the differentiation of osteoblast precursor cells into osteoblastic cells rather than stimulating further differentiation of osteoblastic cells into mature osteoblasts. In addition, grafts of fresh human bone marrow cells of cfu-F stimulated by rhBMP-2 may have the potential to promote bone formation at sites of nonunion as well as around titanium joint prostheses.

Identification of CRAMP, a cathelin-related antimicrobial peptide expressed in the embryonic and adult mouse

Cathelicidins are the precursors of potent antimicrobial peptides that have been identified in several mammalian species. Prior work has suggested that members of this gene family can participate in host defense through their antimicrobial effects and activate mesenchymal cells during wound repair. To permit further study of these proteins a reverse transcriptase-polymerase chain reaction approach was used to identify potential mouse homologs. A full-length 562-base pair cDNA clone was obtained encoding an NH2-terminal prepro domain homologous to other cathelicidins and a unique COOH-terminal peptide. This gene, named Cramp for cathelin-related antimicrobial peptide, was mapped to chromosome 9 at a region of conserved synteny to which genes for cathelicidins have been mapped in pig and man. Northern blot analysis detected a 1-kilobase transcript that was expressed in adult bone marrow and during embryogenesis as early as E12, the earliest stage of blood development. Reverse transcriptase-polymerase chain reaction also detected CRAMP expression in adult testis, spleen, stomach, and intestine but not in brain, liver, heart, or skeletal muscle. To evaluate further the expression and function of CRAMP, a peptide corresponding to the predicted COOH-terminal region was synthesized. CD spectral analysis showed that CRAMP will form an amphipathic alpha-helix similar to other antimicrobial peptides. Functional studies showed CRAMP to be a potent antibiotic against Gram-negative bacteria by inhibiting growth of a variety of bacterial strains (minimum inhibitory concentrations 0.5-8.0 microM) and by permeabilizing the inner membrane of Escherichia coli directly at 1 microM. Antiserum against CRAMP revealed abundant expression in myeloid precursors and neutrophils. Thus, CRAMP represents the first antibiotic peptide found in cells of myeloid lineage in the mouse. These data suggest that inflammatory cells in the mouse can use a nonoxidative mechanism for microbial killing and permit use of the mouse to study the role such peptides play in host defense and wound repair.

MR of childhood metachromatic leukodystrophy

PURPOSE

To investigate the MR findings of childhood metachromatic leukodystrophy (MLD).

METHODS

Nine MR imaging studies in seven children (five girls and two boys, 10 to 32 months old) with MLD were evaluated retrospectively for the extent and progression of white matter abnormalities and the presence of contrast enhancement.

RESULTS

All seven cases showed symmetric, confluent high signal intensity on T2-weighted images in the periventricular white matter and centrum semiovale. A posterior predominance of white matter abnormalities was noted in all cases. Although initially spared from demyelination in all cases, in one case, the subcortical U fibers were later involved in demyelination of follow-up MR studies. Other sites of involvement were the genu (n = 5) and splenium (n = 6) of the corpus callosum, the posterior limbs of the internal capsule (n = 5), the descending pyramidal tracts (n = 4), the claustrum (n = 4), and the cerebral white matter (n = 2); diffuse brain atrophy was seen in two cases. No enhancement of the lesion was seen on any of the five postcontrast examinations. A "tigroid" pattern, previously described in cases of Pelizaeus-Merzbacher disease, was noted in the centrum semiovale in six cases.

CONCLUSION

In late-infantile MLD, demyelination is more prominent in the occipital region. In addition to demyelination of the periventricular white matter, common manifestations include a "tigroid" pattern and involvement of the corpus callosum, the internal capsule, and the corticospinal tract.

Fibrinogen and fibrinolytic activity in CAPD patients with atherosclerosis and its correlation with serum albumin

OBJECTIVE

It has been suggested that hypoalbuminemia in dialysis patients leads to a hypercoagulable state, however, the relationship between serum albumin and fibrinogen or fibrinolytic activity has not been well-documented. The aim of this study was to investigate the changes of fibrinogen, tissue plasminogen activator (tPA), plasminogen activator inhibitor type-1 (PAI-1), and lipid levels in continuous ambulatory peritoneal dialysis (CAPD) patients with atherosclerosis, and the relationship between those factors and serum albumin.

DESIGN

A cross-sectional study.

SETTING

A university hospital.

PATIENTS

Twenty CAPD patients with atherosclerosis, 49 CAPD patients without atherosclerosis, and 33 normal controls were included. Presence of atherosclerosis was determined by positive results in a stress thallium single-photon emission computed tomography or an ankle brachial index less than 0.9. Coronary angiography and/or Doppler ultrasound of extremities were followed for the patients with positive results to confirm atherosclerotic cardiovascular disease.

MAIN OUTCOME MEASURES

tPA and PAI-1 levels were determined with ELISA method, and fibrinogen with thrombin time method. Serum albumin and lipids were also measured.

RESULTS

Serum albumin and HDL-cholesterol levels were significantly lower, and the ratio of total cholesterol/HDL was significantly higher, in CAPD patients than in normal controls. CAPD patients with atherosclerosis had significantly higher fibrinogen, tPA, and PAI-1 levels than other groups: tPA was an independent predictor of atherosclerotic vascular disease in CAPD patients in stepwise logistic regression analysis. Serum albumin level was inversely correlated with fibrinogen (r = -0.28; p < 0.05) in CAPD patients, but not with tPA or PAI-1 levels. PAI-1 level was correlated with tPA (r = 0.37; p < 0.01) and triglycerides (r = 0.32; p < 0.05).

CONCLUSIONS

Association of high levels of fibrinogen and PAI-1 with lipid disorders may be of importance in the development of atherosclerosis in CAPD patients. Hypoalbuminemia may contribute to atherosclerosis via increased synthesis of fibrinogen.

Identification of the binding site in intercellular adhesion molecule 1 for its receptor, leukocyte function-associated antigen 1

Intercellular adhesion molecule 1 (ICAM-1, CD54) is a member of the Ig superfamily and is a counterreceptor for the beta 2 integrins: lymphocyte function-associated antigen 1 (LFA-1, CD11a/CD18), complement receptor 1 (MAC-1, CD11b/CD18), and p150,95 (CD11c/CD18). Binding of ICAM-1 to these receptors mediates leukocyte-adhesive functions in immune and inflammatory responses. In this report, we describe a cell-free assay using purified recombinant extracellular domains of LFA-1 and a dimeric immunoadhesin of ICAM-1. The binding of recombinant secreted LFA-1 to ICAM-1 is divalent cation dependent (Mg2+ and Mn2+ promote binding) and sensitive to inhibition by antibodies that block LFA-1-mediated cell adhesion, indicating that its conformation mimics that of LFA-1 on activated lymphocytes. We describe six novel anti-ICAM-1 monoclonal antibodies, two of which are function blocking. Thirty-five point mutants of the ICAM-1 immunoadhesin were generated and residues important for binding of monoclonal antibodies and purified LFA-1 were identified. Nineteen of these mutants bind recombinant LFA-1 equivalently to wild type. Sixteen mutants show a 66-2500-fold decrease in LFA-1 binding yet, with few exceptions, retain binding to the monoclonal antibodies. These mutants, along with modeling studies, define the LFA-1 binding site on ICAM-1 as residues E34, K39, M64, Y66, N68, and Q73, that are predicted to lie on the CDFG beta-sheet of the Ig fold. The mutant G32A also abrogates binding to LFA-1 while retaining binding to all of the antibodies, possibly indicating a direct interaction of this residue with LFA-1. These data have allowed the generation of a highly refined model of the LFA-1 binding site of ICAM-1.

Size-dependent dextran transport across rat alveolar epithelial cell monolayers

The transport of dextrans (approximately 4 to approximately 150 kDa) across an in vitro model of the alveolar epithelial barrier was studied to determine the effects of molecular size on pulmonary absorption of macromolecular drugs. Fluorescein isothiocyanate (FITC)-labeled dextrans (FDs) with average molecular weights (all in kDa) of 3.86 (FD4), 9 (FD10), 19.8 (FD20), 40.5 (FD40), 71.6 (FD70), and 156.9 (FD150) were utilized as model macromolecular drugs. Unidirectional fluxes of FDs at 37 and 4 degrees C were measured from the appearance rates of FD in the receiver fluid of open-circuited monolayers (>2000 omega-cm2) of rat alveolar epithelial cells. Apparent permeability coefficients (P(app)) were estimated from the observed flux and the corresponding concentration gradient of FD. Results showed that FD fluxes were the same in both apical-to-basolateral (AB) and opposite (BA) directions at each molecular weight studied. The P(app) was not significantly different at 0.5 and 1.0 mg/mL FD40 donor concentrations. The FD P(app) (x 10(-8)cm/s) decreased gradually from 1.35 for FD4 to 0.32 for FD40, indicating an apparent inverse relationship between P(app) and molecular weight of FD. By contrast, P(app) was about the same at 0.13 for both FD70 and FD150. When experimental temperature was lowered to 4 degrees C, P(app) decreased by approximately 40% for FDs of 4 through 40 kDa, whereas the decrease in P(app) was by approximately 80% for larger FDs of both 70 and 150 kDa. Moreover, these FDs were found to be relatively intact (approximately 90%) in either receiver fluid after 5-h flux experiments without detectable levels of metabolites in the respective donor fluid, suggesting that alveolar epithelial cells allow translocation of FDs intact across the barrier. Equivalent pore analysis, assuming restricted diffusion of FDs of 4-40 kDa via cylindrical, water-filled pores across the cell monolayer revealed a population of large equivalent pores with approximately 5.6 nm radius. These data suggest that smaller macromolecules (radius <5 nm) traverse the alveolar epithelial barrier via paracellular pathways, and that larger (i.e., radius > or = 6 nm) macromolecules likely cross the barrier via other pathways (e.g., pinocytosis).

Effects of Mycobacterium tuberculosis on the bioelectric properties of the alveolar epithelium

To investigate the hypothesis that Mycobacterium tuberculosis penetrates the alveolar epithelium by downregulating its barrier properties, we evaluated the interactions between M. tuberculosis and rat alveolar epithelial cell monolayers that are believed to share electrophysiologic properties of the human alveolar epithelium. Nonproteinaceous components of M. tuberculosis caused marked declines in electrical resistance and equivalent short-circuit current of the alveolar epithelial cell monolayers, indicating a reduction in the capacity to maintain tight intercellular junctions and to actively reabsorb sodium. M. tuberculosis elicited production of TNF-alpha mRNA and protein by alveolar epithelial cells, and the effects of recombinant TNF-alpha on the bioelectric properties of the alveolar epithelial paralleled those of M. tuberculosis. Furthermore, the effects of M. tuberculosis on alveolar epithelial resistance were abrogated by neutralizing anti-TNF-alpha antibodies. These results indicate that M. tuberculosis elicits production of TNF-alpha, which in turn reduces the bioelectric barrier properties of the alveolar epithelium. These findings provide insight into potential mechanisms by which M. tuberculosis establishes infection and disease in the lung.

Comparison of three rodent neuropathic pain models

To characterize various animal models of neuropathic pain, we compared three previously developed rat models using the same behavioral testing methods. These models involve: (1) chronic constriction injury by loose ligation of the sciatic nerve (CCI); (2) tight ligation of the partial sciatic nerve (PSL); and (3) tight ligation of spinal nerves (SNL). Comparisons were made for the time course of behavioral signs representing various components of neuropathic pain as well as for the effects of surgical sympathectomy. In general, all three methods of peripheral nerve injury produced behavioral signs of both ongoing and evoked pain with similar time courses. However, there was a considerable difference in the magnitude of each pain component between models. Signs of mechanical allodynia were largest in the SNL injury and smallest in the CCI model. On the other hand, behavioral signs representing ongoing pain were much more prominent in the CCI model than in the other two. Although the behavioral signs of neuropathic pain tended to decrease after sympathectomy in all three models, the change was most evident in the SNL model. The results of the present study suggest that the three rat models tested have contrasting features, yet all are useful neuropathic pain models, possibly representing different populations of human neuropathic pain patients.

The vesico-urethral pressuregram analysis of urethral function under stress

About one-third of older multiparous women are prone to stress urinary incontinence (SUI): unwanted urine loss during activities which suddenly raise intra-abdominal pressure. In this paper we describe and test a method for visualizing and analyzing the function of the urinary continence control system (CCS) under stress. Intravesical and intraurethral pressure changes from the resting state were recorded at proximal, mid-, and distal urethral locations during increasingly severe coughs and cross-plotted on a 'vesico-urethral pressuregram.' The slope (alpha) and intercept (chi zero) resulting from a linear regression analysis of these data were used to develop a continence equation which can be used to predict the equilibrium point pressure (PE): the intravesical pressure at which urine will leak to the intraurethral pressure recording site. We tested the null hypothesis that these parameters would not differ in six young, nulliparous continent women (mean +/- S.D. age: 30 +/- 3.5 yr) and six multiparous SUI women (52.3 +/- 8.0 yr, parity: 1.7 +/- 0.8), or between urethral locations. Significant differences in continence equation parameters were found between groups and in different urethral locations. In the SUI group static factors calculated from the term (1 - alpha) contributed 27% of the mean (S.D.) midurethral PE value, 145 (46) cm H2O, while dynamic factors, estimated from alpha, contributed 73% of this value. Valuable insights for improving the diagnosis and treatment of SUI may be obtained by analyzing the relative contributions of alpha and chi 0 to urethral closure during physical stress.

The factors related to recurrence after transcatheter arterial embolization for the treatment of hemoptysis

OBJECTIVES

Massive hemoptysis is a major clinical problem associated with high morbidity and mortality. Transcatheter arterial embolization is widely used for the treatment of massive hemoptysis, but it was reported that the recurrence rate after embolization is 12-54% in the previous studies. We evaluated the therapeutic effect of transcatheter arterial embolization for the treatment of massive hemoptysis and the factors related to recurrence.

METHODS

We reviewed 51 patients (M:F = 36:15) of transcatheter arterial embolization for the treatment of massive hemoptysis from Jan 1988 to Dec 1994, retrospectively.

RESULTS

After arterial embolization, immediate successful control (< 1 wk) of massive hempotysis was achieved in 48 of 51 patients (94.1%) and recurrence of hemoptysis was observed in 17 of 51 patients (33.3%) during the follow-up period. The patients with non-bronchial artery hemoptysis and multiple artery bleeding had increased tendency of recurrence (77.7%). On the previous history of hemoptysis, the patients with massive hemoptysis (> 400 ml/24hr) or frequent history of hemoptysis had increased tendency of recurrence (87.5%, 72.7%).

CONCLUSION

Transcatheter arterial embolization is a useful and safe procedure for immediate control in massive hemoptysis. However, the patients with this procedure had a potentiality for recurrence. We suggest that close follow-up and caution will be needed in the patients with multiple artery bleeding or with large amounts of hemoptysis or with previous episodes more than 3 times.

Large amounts of polyethylene debris in the interface tissue surrounding bipolar endoprostheses. Comparison to total hip prostheses

A histologic and biochemical comparison of interface membranes around femoral components of bipolar endoprostheses (n = 17) and total hip prostheses (n = 17) inserted without cement was conducted. The patients' profiles were similar in both groups with respect to age, sex, primary diagnosis, weight, and the interval between primary and revision arthroplasty. Macroscopically, marked circumferential abrasion of the polyethylene insert in the retrieved bipolar cups was noted. Histologic analysis revealed significantly larger amounts of polyethylene debris in the bipolar group. The membranes from the bipolar group also produced significantly greater amounts of prostaglandin E2 (P < .05). The inflammatory membranes associated with large amounts of polyethylene debris may have contributed to aseptic loosening and osteolysis in patients with a bipolar hip prosthesis.

Permeability characteristics of primary cultured rabbit conjunctival epithelial cells to low molecular weight drugs

PURPOSE

To evaluate the permeability characteristics of primary cultured rabbit conjunctival epithelial cell (RCEC) layers to low molecular weight drugs of varying lipophilicity.

METHODS

3H-mannitol; hydrophilic sotalol and atenolol; moderately lipophilic metoprolol, timolol, propranolol; and highly lipophilic betaxolol were used as model compounds.

RESULTS

The conjunctival apparent permeability coefficient (Papp) of mannitol (1 x 10(-7) cm/s) was 2.4 times lower than that of the most hydrophilic beta-blocker, sotalol (Papp = 2.4 x 10(-7) cm/s). Differences in the degree of tightness of the epithelial cell layers brought about a 30-fold difference in the transport of atenolol in favor of the leaky cell layers, while not affecting the transport of the lipophilic drug, propranolol. Within the log partition coefficient (PC) range of -0.62 (sotalol) and 3.44 (betaxolol), there was a hundred-fold difference in the Papp. A sigmoidal curve was used to depict the influence of lipophilicity on solute permeation across conjunctival epithelial cell layers. An effective half-maximal Papp was observed at a log PC value of 1.2.

CONCLUSIONS

These findings on the lipophilicity effect on drug transport are generally similar to those reported for the isolated rabbit conjunctiva, suggesting the utility of cultured rabbit conjunctival epithelial cell layers as an in vitro model for evaluating drug transport.

A primary culture model of rabbit conjunctival epithelial cells exhibiting tight barrier properties

PURPOSE

The present study was conducted to develop and characterize a functional primary culture of pigmented rabbit conjunctival epithelial cells on permeable support exhibiting tight barrier properties.

METHODS

Conjunctival epithelial cells were isolated by 0.2% protease treatment, cultured at 0.5-1.8 x 10(6) cells/cm2 onto collagen-treated Transwell filters, and were maintained either in the presence of 1% fetal bovine serum throughout or serum-free media from day 3 onwards. Transepithelial potential difference (PD) and transepithelial electrical resistance (TEER) were measured and equivalent short-circuit current (Ieq = PD/TEER) estimated.

RESULTS

There appears to be a critical plating density of 1.5 x 10(6) cells/cm2 for functional development of tight epithelial cell cultures. The culture conditions as noted above did not affect either the time when peak bioelectric parameters were attained (days 8-10) or the magnitude of these parameters at a plating density of 1.5 x 10(6) cells/cm2. Specifically, cells grown in a serum-free media showed a peak TEER of 1.9 +/- 0.2 k omega.cm2, a PD of 14.2 +/- 1.6 V (apical side negative), and and Ieq of 8.0 +/- 0.4 microA/cm2 (mean +/- SEM, n = 45). Electron microscopy of serum-weaned cultures revealed a multilayered epithelium with numerous microvilli on the outermost layer of cells, while sporadic positive Periodic Acid Schiff (PAS) staining under light microscopy suggested the presence of mucin-secretory goblet cells.

CONCLUSIONS

A functional, tight, epithelial barrier of the pigmented rabbit conjunctiva on a permeable support has been developed, which may be useful for mechanistic studies of ion and drug transport at the cellular level.