Unexpected recurrent seizures following repeated spinal injections of tetracaine--a case report

A 36-year-old male patient was scheduled to undergo ureteroscopic lithotomy because of left ureteral stone under spinal anesthesia. After receiving a renewed spinal anesthesia with 8 mg tetracaine to compensate for the first attempt (with 10 mg tetracaine), which proved to be a failure, he was soon seized with episodic seizure attacks. Central nervous system toxicity of the local anesthetic might be the cause of the seizure. We brought forward this case for discussion for warning that the possibility of systemic toxicity of local anesthetic might exist despite a seemingly undisputable spinal anesthesia.

Negative regulation of expression of the Bacillus megaterium bmlP1 gene by the bmlP1 3' flanking region

We report that the expression of the Bacillus megaterium bmlP1 gene is subject to negative regulation by the bmlP1 3' flanking region. This repression occurred both in B. megaterium and in Escherichia coli. When the bmlP1 promoter was replaced with a heterologous promoter or when the orientation of the bmlP1 3' flanking region was reversed, the inhibitory effect was still observed. However, the bmlP1 3' flanking region was unable to exert repression on a heterologous gene when fused downstream in either orientation, and it was incapable of acting in trans. Dot blot and Northern blot analyses revealed that the repression occurred at the RNA level. Deletion analysis showed that the regulatory site responsible for the repression is located within a 116-bp region immediately following the bmlP1 gene. Possible mechanisms for this repression are discussed.

[cDNA cloning, fusion expression in Escherichia coli and activity assay of hIL-11]

Human Interleukin-11 (hIL-11) is a multifunctional cytokine which plays an important role in regulating the proliferation and differentiation of cells in the hematopoeitic, lymphoid system etc. To obtain the IL-11 cDNA, a primary culture of Chinese fetal lung fibroblast was prepared from fresh tissue. Then the human IL-11 cDNA without the N-terminal signal peptide sequence was cloned by RT-PCR from the cells induced by PMA. The sequence indicated that there are three bases different from those previously reported, but with no change of the amino acids. The cDNA was inserted into the 3' end of trxA gene in thioredoxin gene fusion expression system pTRXFUS to construct the trxA and hIL-11 fusion expression vector, and expressed in E. coli. The fusion hIL-11 accounts for more than 20% of the total bacteria proteins. The expression product is present in soluble forms and has the full biological and immunological activities.

Sphingosine-1-phosphate signaling via the EDG-1 family of G-protein-coupled receptors

The bioactive lipid sphingosine-1-phosphate (SPP) is abundantly formed and released during the activation of platelets by thrombotic stimuli. Once exported, SPP interacts with the G-protein-coupled receptors (GPCR) of the EDG-1 family. SPP binds to EDG-1 with the dissociation constant of approximately 8 nM and induces signal transduction events such as mitogen-activated protein kinase (MAP kinase) activation, decrease of cAMP levels, remodeling of the actin cytoskeleton, among others. EDG-1 is a prototypical member of a large family of GPCRs that interact with glycero- and sphingolysolipid phosphates, namely, SPP and lysophosphatidic acid (LPA). Three other GPCRs, trivially termed EDG-3, EDG-5, and EDG-8, are also high-affinity receptors for SPP. The four SPP receptor subtypes regulate different intracellular signal transduction pathways. In vascular endothelial cells, cooperative signaling between EDG-1 and EDG-3 subtypes of SPP receptors results in adherens junction assembly, cell survival, morphogenesis into capillary-like networks, and angiogenesis. SPP acts distinctly, albeit cooperatively, with polypeptide angiogenic factors, resulting in the formation of mature neovessels. Thus SPP signaling as an extracellular mediator via the EDG-1 family of GPCRs may be a heretofore unrecognized mechanism for the regulation of angiogenesis and vascular endothelial cell function.

Induction of integrin-associated protein (IAP) mRNA expression during memory consolidation in rat hippocampus

We have previously demonstrated that hippocampal integrin-associated protein (IAP) gene expression is associated with memory formation in a one-way inhibitory avoidance learning in rats. In the present study, we further investigated the role and mechanism of IAP involved in memory consolidation in rats. Because of the minute amount of IAP present in the brain, we have adopted the quantitative reverse transcription-polymerase chain reaction (RT-PCR) method. Our results revealed that hippocampal IAP mRNA expression is approximately fourfold higher in rats showing good memory retention (GM, retention score of 600 s) at 3 h, but not at other time points, after training when compared with the poor memory rats (retention score < 80 s). On the other hand, integrin alphav mRNA level was markedly increased ( approximately twofold), while integrin beta3 mRNA level was decreased ( approximately 50%) at 1 h post-training. Further, separate sets of RT-PCR analysis revealed that IAP5 and IAP6 mRNA expressions, but not that of IAP7, were markedly increased in GM rats 3 h post-training. Moreover, regional distribution studies revealed that different isoforms of the IAP gene are similarly distributed in different brain areas, while IAP7 has been the predominant form present in astrocyte cells. These results together suggest that IAP mRNA expression is indeed induced upon training, rather than that the GM rats have constitutively higher levels of IAP. The unparallel change of IAP and integrin mRNA expressions as far as time-course is concerned suggests that they are possibly involved in different forms and stages of memory processing. Further, IAP5 and IAP6 are more closely associated with memory consolidation, while IAP7 may constitute the major isotype for signal transduction in astrocyte cells.

[Studies on quality standards for Pollen Typhae(puhuang)]

OBJECTIVE

To work out quality standards for Pollen Typhae(Puhuang).

METHOD

Isorhamnetin-3-O-neohesperidoside, typhaneoside, isorhamnetin and beta-sitosterol in Pollen Typhae marketed in ten cities of China were identified by TLC. The contents of isorhamnetin-3-O-neohesperidoside and typhaneoside were determined by HPLC.

RESULT

The method is sensitive and specific for identifying isorhamnetin-3-O-neohesperidoside, typhaneoside, isorhamnetin and beta-sitosterol. The linear ranges of isorhamnetin-3-O-neohesperidoside and typhaneoside were 0.188-0.940 microgram with and average recovery of 97.77%; and 0.164-0.820 microgram with an average recovery of 98.42% respectively.

CONCLUSION

The method can be used both qualitatively and quantitatively as standards for the quality control of Pollen Typhae.

Immediate repair of intestinal injury during laparoscopically assisted vaginal hysterectomy

With the increasing popularity of laparoscopic surgery in gynecologic diseases, complications with this procedure are noted more frequently. The majority of complications occur during operation, and most of the cases are immediately identified. The recovery and outcome are relatively good due to urgent repair and management. Herein, we report a complication--a trocar, inducing small intestinal damage, which was detected during laparoscopically assisted vaginal hysterectomy. The damage was repaired promptly extraperitoneally with an uneventful recovery. Through a review of the literature and our experience, possible preventive methods of this complication are discussed. In addition, by this case review, we hoped that such a complication could be avoided in the future.

Impact of assisted reproductive technology on modern medicine

A surge in knowledge and interest in reproductive biology has occurred since the advent of assisted reproductive technology (ART) in the 1960s. These innovative medical advances soon challenged societies and invited criticism. Nevertheless, ART has superseded older therapies and serves as a back-up when all else fails. There are currently 61 ART clinics in Taiwan. Thanks to a group of young physicians and scientists who have devoted great effort in catching up with the modern advances in assisted reproduction, most of the important advances in ART have been introduced to Taiwan promptly and resulted in good success rates. The complications of multifetal pregnancies as well as controversies regarding gestational surrogacy and new technologies such as intracytoplasmic sperm injection, preimplantation genetic diagnosis, and cloning have challenged conventional wisdom, ethics, laws, and religions. Society now faces a dilemma in striking a balance among science, ethics, and human rights. It is, thus, advisable that we stand back once in a while and carefully consider where we should go next.

Nitric oxide synthase inhibitor ameliorates oral total parenteral nutrition-induced barrier dysfunction

The expression of inducible nitric oxide synthase (iNOS) is increased in the intestine and results in mucosal damage after endotoxin challenge. Although the oral administration of total parenteral nutrition (TPN) solution promotes bacterial translocation (BT) and increases the intestinal permeability, the role of NO in the nutrition-induced loss of mucosal barrier function remains unclear. The distribution of fluorescein isothiocyanate-dextran (FITC-dextran, 4400) across the lumen of small intestine in rat was examined to investigate the role of NOS activity on the intestinal permeability under oral TPN feeding. Fifty-one rats were randomly divided into 4 groups. Group I (control group) was fed with rat chow, group II received TPN solution orally. Groups III and IV received TPN solution supplemented with NOS inhibitors. On day 9, FITC-dextran was injected into the intestinal lumen. After 30 min, blood samples were taken from portal vein and analyzed for plasma FITC-dextran level by fluorescence spectrophotometry. Samples of small intestine were frozen and sectioned in a cryostat for morphological and NOS histochemical studies. Homogenates of small intestine were used for NOS activity measurement. The plasma level of FITC-dextran showed a significant increase (P < 0.05) in rats fed with oral TPN compared with the control ones. Supplement with NOS inhibitors significantly decreased the intestinal permeability in groups III and IV compared with group II. Similarly, the total NOS activities showed a significant 2-fold increase (P< 0.05) in group II, and NOS inhibitors decreased the elevated NOS activity. These data suggest that oral TPN feeding for 9 days leads to an increase in permeability to dextran and the total NOS activity of small intestine, and both induction of the intestinal permeability and NOS activity were inhibited by treatment with NOS inhibitors. Addition of S-methylisothiourea (SMT), an iNOS selective inhibitor, profoundly inhibited 66% of the induced iNOS activity (P < 0.05) and reduced 74% of the diet-induced increase in intestinal permeability (P < 0.05) in group II. The induced permeability change in rats receiving oral TPN is mainly due to the activity of intestinal mucosal iNOS. The induction of iNOS is an important mediator for intestinal barrier dysfunction. Administration of SMT, which specifically decreases iNOS activity, is useful in the prevention of diet-induced barrier failure.

[Ribozyme which specifically cleave 12-lipoxygenase mRNA: in vitro activity and its dynamics]

The ribozyme gene which specifically cleaved 12-lipoxygenase mRNA was designed, synthesized and cloned according to hammer-head ribozyme model. A 25-bp-long segment of 12-lipoxygenase mRNA was chemically synthesized as substrate, which was incubated with transcribed ribozyme RNA to detect its cleavage activity in vitro. The results showed that the ribozyme had a relatively high cleavage activity against 12-lipoxygenase mRNA segment at 37 degrees C. It's kcat value and Km value was 0.083/min and 1300 nmol/L respectively. The ribozyme had a very high activity at 50 degrees C and its kcat value was 0.31/min.

Lighting direction affects recognition of untextured faces in photographic positive and negative

Face recognition in photographic positive and negative was examined in a same/different matching task in five lighting direction conditions using untextured 3-D laser-scanned faces. The lighting directions were +60, +30, 0, -30 and -60 degrees, where negative values represent bottom lighting and positive values represent top lighting. Recognition performance was better for faces in positive than in negative when lighting directions were at +60 degrees. In one experiment, the same effect was also found at +30 degrees. However, faces in negative were recognized better than positive when the direction was -60 degrees. There was no difference in recognition performance when the lighting direction was 0 and -30 degrees. These results confirm that the effect of lighting direction can be a determinant of the photographic negative effect. Positive faces, which normally appear to be top-lit, may be difficult to recognize in negative partly because of the accompanying change in apparent lighting direction to bottom-lit.

Enterovesical fistula: experiences with 41 cases in 12 years

BACKGROUND

A retrospective analysis of enterovesical fistula treated at Chang Gung Memorial Hospital was conducted to determine the optimal diagnosis and management of this disease.

METHODS

The records of 41 patients who presented from 1984 to 1996 and had a final diagnosis of enterovesical fistula were retrospectively reviewed. The etiology, symptoms on presentation, diagnostic tools, and modality of treatment were analyzed.

RESULTS

The majority of these cases were associated with malignancy (38, 92.7%), and the others with diverticulitis (2, 4.9%) and iatrogenic causes (1, 2.4%). In those with malignancy, 15 patients (39.5%) were found to have tumor recurrence. The most frequent symptom in enterovesical fistula was fecaluria (58.5%), followed by abdominal pain (22%) and dysuria (14.6%). Diagnostic tools included the barium enema, cystography, and cystoscopy; these methods could identify the fistula in 63.2%, 60%, and 53.8% of the patients, respectively. Methods of management included diversion only (39%), one-stage fistula repair (36.6%), and watchful surveillance (24.4%).

CONCLUSION

Enterovesical fistula should be considered if fecaluria, pneumaturia, or persistent non-specific urinary tract infection present as the initial complaint. A thorough surgery for a possible underlying malignancy is mandatory when confronted with enterovesical fistula, since the incidence of inflammatory bowel disease is low in this area. An abdominal computer tomography (CT) scan, barium enema, and cystogram can be useful diagnostic tools. Treatment of this entity should be individualized according to each patients clinical status.

Vascular endothelial cell adherens junction assembly and morphogenesis induced by sphingosine-1-phosphate

Vascular endothelial cells undergo morphogenesis into capillary networks in response to angiogenic factors. We show here that sphingosine-1-phosphate (SPP), a platelet-derived bioactive lipid, activates the EDG-1 and -3 subtypes of G protein-coupled receptors on endothelial cells to regulate angiogenesis. SPP induces the Gi/mitogen-activated protein kinase/cell survival pathway and the small GTPase Rho- and Raccoupled adherens junction assembly. Both EDG-1-and EDG-3-regulated signaling pathways are required for endothelial cell morphogenesis into capillary-like networks. Indeed, SPP synergized with polypeptide angiogenic growth factors in the formation of mature neovessels in vivo. These data define SPP as a novel regulator of angiogenesis.

Sphingosine-1-phosphate: extracellular mediator or intracellular second messenger?

Sphingosine-1-phosphate (SPP), a polar sphingolipid metabolite, has received much attention recently as an extracellular mediator and an intracellular second messenger. It regulates a wide range of biological responses such as cell growth, death, differentiation, and migration. Recent identification of plasma membrane receptors and the cloning of SPP metabolizing enzymes have increased our understanding of the biology of SPP synthesis and action. However, controversy exists regarding the mode of action of this molecule. EDG-1 and related G-protein-coupled receptors were identified recently as plasma membrane receptors for SPP. In light of this recent discovery, many of the functions of SPP previously thought to be due to intracellular second messenger action should be reevaluated. In addition, signaling properties and functions of the three known receptors for SPP need to be fully delineated. The structures and the evolutionary conservation of SPP metabolizing enzymes from yeast to mammals support the hypothesis that SPP also plays a role as an intracellular second messenger. However, definitive assignment of the intracellular role of SPP awaits purification/molecular cloning of elusive intracellular receptors. Better knowledge of the molecular basis of SPP action is needed to assess the physiological and pathophysiological significance of this bioactive lipid mediator.

Development of spatial and temporal vision during childhood

Using the method of limits, we measured the development of spatial and temporal vision beginning at 4 years of age. Participants were adults, and children aged 4, 5, 6, and 7 years (n = 24 per age). Spatial vision was assessed with vertical sine-wave gratings, and temporal vision was assessed with an unpatterned luminance field sinusoidally modulated over time. Under these testing conditions, spatial contrast sensitivity at every frequency increased by at least 0.5 log units between 4 and 7 years of age, at which point it was adult-like. Grating acuity reached adult values at 6 years of age. Temporal vision was more mature: at 4 years of age temporal contrast sensitivity at higher temporal frequencies (20 and 30 Hz) and critical flicker fusion frequency were already adult-like. Sensitivity at lower temporal frequencies (5 and 10 Hz) increased by 0.25 log units after the age of 4 to reach adult levels at age 7. The results suggest that temporal vision matures more rapidly than spatial vision during childhood. Thus, spatial and temporal vision are likely mediated by different underlying neural mechanisms that mature at different rates.

Are there qualitative differences between face processing in photographic positive and negative?

The question whether face recognition in photographic negative relies more on external features and pictorial cues than in photographic positive was studied in five experiments. Recognition of whole faces as well as both external and internal features of the faces was compared in experiments 1 and 2. The conditions in which views of faces between learning and test were either identical (hence providing maximum pictorial cues) or different (hence reducing such cues) were compared in experiments 3, 4, and 5. The results showed that recognition of internal features in two-tone and multi-tone images suffered more from use of photographic negatives than recognition of external features. Testing with both multi-tone and two-tone images revealed that the deficit caused by view changes between learning and test was no more severe with negatives than with positives. Finally, removing external features made recognition of different views equally more difficult for positives and negatives. Overall, these results point to a qualitative rather than quantitative difference between processing face images in photographic positive and negative.

Cyclooxygenase-1 and -2 isoenzymes

The cyclooxygenase isoenzymes (COX-1 and -2) catalyze the rate-limiting steps in prostanoid biosynthesis. COX-1 and -2 genes encode two isoenzymes with overlapping yet distinct expression patterns and functions. Physiologically, various extracellular stimuli such as growth factors, cytokines and tumor promoters regulate the expression of COX-1 and -2 genes at both transcriptional and post-transcriptional levels. COX-2 is overexpressed in rheumatoid arthritis, colorectal and breast cancer. Prostanoids produced by the COX pathway signal via plasma membrane-localized, G-protein-coupled receptors as well as via nuclear receptors. Currently, several COX-2-selective inhibitors are developed to control the anti-inflammatory and anti-neoplastic activities of the COX-2 isoenzyme. Inhibition of the COX isoenzyme activity and/or expression may be the basis of future generation of anti-inflammatory and anti-neoplastic drugs.

Efficiency of supercritical fluid extraction for determining 4-nonylphenol in municipal sewage sludge

When the sewage sludge containing the persistent, lipophilic, metabolite 4-nonylphenol (4-NP) has been disposed of in the environment it's toxic nature can lead to serious health risks to human beings and can also affect plants and aquatic organisms. Supercritical fluid extraction (SFE) is a new and powerful technique for extracting the organic contaminants from the solid phase. The present study was conducted to investigate optimal conditions for the quantitative extraction of 4-NP by SFE and to determine the concentration of 4-NP in municipal sewage sludge. The effect of several parameters such as temperature, pressure, static extraction time, dynamic extraction time, CO2 flow-rate, sample mass and modifier on the extraction were investigated. The optimal conditions for the extraction of the spiked sample were fluid pressure 97 bar, temperature 40 degrees C, flow-rate 3.0 ml/min, static extraction time 2 min, dynamic extraction time 5 min and modifier methanol (0.5 ml). Extracts were analyzed by gas chromatography-mass spectrometry. Concentration of 4-NP in the anaerobically degraded sludge of the De-Haw Sewage Treatment Plant in Taiwan was found to be 243.9 mg/kg. The extraction efficiency of the SFE method was compared with the conventional Soxhlet extraction method. The overall recovery of the SFE method was found to be greater and the results indicate that SFE is an efficient method for extracting 4-NP from sewage sludge.

Ligand-induced trafficking of the sphingosine-1-phosphate receptor EDG-1

The endothelial-derived G-protein-coupled receptor EDG-1 is a high-affinity receptor for the bioactive lipid mediator sphingosine-1-phosphate (SPP). In the present study, we constructed the EDG-1-green fluorescent protein (GFP) chimera to examine the dynamics and subcellular localization of SPP-EDG-1 interaction. SPP binds to EDG-1-GFP and transduces intracellular signals in a manner indistinguishable from that seen with the wild-type receptor. Human embryonic kidney 293 cells stably transfected with the EDG-1-GFP cDNA expressed the receptor primarily on the plasma membrane. Exogenous SPP treatment, in a dose-dependent manner, induced receptor translocation to perinuclear vesicles with a tau1/2 of approximately 15 min. The EDG-1-GFP-containing vesicles are distinct from mitochondria but colocalize in part with endocytic vesicles and lysosomes. Neither the low-affinity agonist lysophosphatidic acid nor other sphingolipids, ceramide, ceramide-1-phosphate, or sphingosylphosphorylcholine, influenced receptor trafficking. Receptor internalization was completely inhibited by truncation of the C terminus. After SPP washout, EDG-1-GFP recycles back to the plasma membrane with a tau1/2 of approximately 30 min. We conclude that the high-affinity ligand SPP specifically induces the reversible trafficking of EDG-1 via the endosomal pathway and that the C-terminal intracellular domain of the receptor is critical for this process.

Molecular characterization of germline mutations in the BRCA1 and BRCA2 genes from breast cancer families in Taiwan

A total of 18 families with multiple cases of breast cancer were identified from southern Taiwan, and 5 of these families were found to carry cancer-associated germline mutations in the BRCA1 and BRCA2 genes. One novel cryptic splicing mutation of the BRCA1 gene, found in two unrelated families, was shown to be a deletion of 10 bp near the branch site in intron 7. This mutation causes an insertion of 59 nucleotides derived from intron 7 and results in a frameshift, leading to premature translational termination of BRCA1 mRNA in exon 8. Deletions of 2670delC, 3073delT and 6696-7delTC in the BRCA2 gene were found in three other breast cancer families. All three deletions are predicted to generate frameshifts and to result in the premature termination of BRCA2 protein translation. Several genetic polymorphisms in both BRCA1 and BRCA2 genes were also detected in this investigation.

High-performance liquid chromatographic method for determination of tramadol in human plasma

A modified high-performance chromatographic method using UV detection was developed for determination of tramadol concentration in human plasma. Plasma samples were extracted with ethyl acetate in a one-step liquid-liquid extraction (recovery 88.5+/-2.1%). Analysis of the extract was performed on a reversed-phase LiChrospher 60 RP-select B column with a particle size of 5 microm. The mobile phase consisted of 0.05 M KH2PO4 aqueous solution (pH 3.5) and acetonitrile in a ratio of 90:10 (v/v). Metoprolol was used as the internal standard and UV detection at 225 nm was employed. Accuracy of the assay in the concentration range examined was from 1.3 to 11.9% for the intra-day run and from 1.4 to 8.1% for the inter-day run. The precision of this method varied from 1.2 to 8.7%. The reproducibility of the method was determined to be from 0.8 to 7.2% over the six-day period. A limit of detection was 9 ng/ml at a signal-to-noise ratio of 3. This validated method was then applied to the determination of tramadol concentrations in healthy volunteers after oral administration of 100 mg of tramadol in capsules of Painlax and Tramal.

Studies on the determination of diacetyl guanfubase A concentration in rabbit plasma and pharmacokinetics

A gas chromatographic method for monitoring diacetyl guanfubase A in plasma is described. The procedure involved a single solvent extraction of drug from rabbit plasma into ethyl acetate with guanfubase A as an internal standard. The extract was analyzed subsequently on a gas chromatograph equipped with a hydrogen flame ionization detector. The recovery was 86.43% +/- 6.90% (+/- SD); the RSD of within-day and between-day was 2.81%-5.26% and 5.22%-8.24%, respectively; the regression line was linear over the concentration range of 25-200 micrograms/mL, the limit of detection was 10 micrograms/mL. No endogeneous interference was found in chromatograms of the biological samples. This method was applied to the pharmacokinetic study of diacetyl guanfubase A in rabbits.

Surgical and pathologic observations of epididymal tubules during microscopic epididymal sperm aspiration for intracytoplasmic sperm injection

Microscopic epididymal sperm aspiration (MESA) for sperm retrieval and intracytoplasmic sperm injection (ICSI) is currently our routine treatment for selected male patients with obstructive azoospermia. In order to refine the surgical technique and obtain better quality sperm for our assisted reproductive technology program, we observed the epididymal tubules in 40 sessions of surgical exploration of the epididymis for sperm aspiration. Epididymal tubules with long-term obstruction could be divided into three groups on the basis of clinical observations and pathology findings: markedly dilated, mildly dilated, and nondilated. All of the markedly dilated epididymal tubules (grade III, n = 10) were azoospermic and ICSI could not be done. Epididymal sperm obtained from the mildly dilated tubules (grade II, n = 9) resulted in poorer fertilization (49%) and pregnancy (33%) rates than sperm obtained from nondilated epididymal tubules (grade I, n = 21, fertilization rate 72%, pregnancy rate 57%). These findings demonstrate that nondilated epididymal tubules are best for sperm retrieval and successful ICSI. We believe this observation will be a good surgical parameter for urologic surgeons performing MESA.

The actin cytoskeleton and integrin expression in the recovery of cell adhesion after oxidant stress to a proximal tubule cell line (JTC-12)

This study examines the role of the actin cytoskeleton and integrin expression in the recovery of cell adhesion in the proximal tubule cell line JTC-12 after peroxide injury. The cells were exposed to 10, 20, or 50 mM hydrogen peroxide for 10 min and then allowed to recover. Viability measurements by trypan blue exclusion confirmed that the injury was largely nonlethal with 85% viability at 1 h even at 50 mM peroxide. ATP levels fell immediately after the peroxide incubation in all groups to approximately 10% of normal, but already showed some recovery by 1 h and full recovery in the 10 and 20 mM groups by 24 h. Cell adhesion to extracellular matrix immediately after injury was depressed at 20 and 50 mM peroxide, but by 12 h was abnormal only at 50 mM peroxide and at 24 h was essentially normal at all peroxide concentrations. Immediately after exposure to 10 mM peroxide, there were subtle abnormalities in the actin cytoskeleton (thickening of fibrils) as assessed by phalloidin staining, with more pronounced effects at 20 and 50 mM. At 1 h, many cells showed collapse of the actin cytoskeleton to the periphery. There was some recovery at 4 h; by 12 h, the actin cytoskeleton showed further recovery, although was still abnormal (coarsened microfilaments), especially at 20 and 50 mM peroxide. By 24 h, the actin cytoskeleton showed only subtle coarsening. Integrin surface expression was assessed by flow cytometry. The alpha6 subunit on cells exposed to 20 mM peroxide was unchanged at 1 h and 4 h, but by 12 h had increased to 118.5+/-4.5% and by 24 h to 146+/-13.4% of control levels. The expression of the beta1 and alphaVbeta3 integrins remained unchanged. Thus, despite coarsening of the actin cytoskeleton and depressed ATP levels, cell adhesion recovered from oxidant stress. Abnormal cell adhesion after injury was not a consequence of a decrease in integrin expression, and recovery of cell adhesion was not a consequence of the modest and selective increase in integrin expression.