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Biomedical subjects

S Buckley

Publications and source records attributed to S Buckley.

At least 37 records · Page 2Linked to original sources
PubMed2000

Cytokine response during hyperoxia: sequential production of pulmonary tumor necrosis factor and interleukin-6 in neonatal rats.

BACKGROUND: Exposure of newborn animals to high concentrations of oxygen leads to diffuse alveolar damage similar to that seen in bronchopulmonary dysplasia in human infants. Therefore, neonatal rats are a suitable practical model of hyperoxic lung damage in human infants. OBJECTIVE: To determine the involvement of tumor necrosis factor-alpha and interleukin-6 in lung injury in neonatal rats exposed to 100% O2 concentration. METHODS: A randomized controlled study was designed in which litters of term Sprague-Dawley rat pups were assigned to experimental or control groups. The pups in the experimental group were placed in 100% O2 from birth for 9 days, while the control pups were placed in room air. Twelve to 15 pups from each group were sacrificed on day 1, 3, 6, 9 and 13 after birth for bronchoalveolar lavage collection and lung histologic study. The bronchoalveolar lavage fluid was assayed for TNF alpha and IL-6. RESULTS: Newborn rats exposed to 100% O2 for the first 9 days of life showed severe pulmonary edema and hypercellularity on days 1 and 3, which then improved to nearly complete resolution on days 6 and 9. Pulmonary TNF alpha was produced early on O2 exposure (day 3) and pulmonary IL-6 later (days 6 and 9). CONCLUSIONS: Hyperoxia induces sequential production of pulmonary TNF alpha and IL-6, which corresponds to the severity of the pathological findings and the known inflammatory and anti-inflammatory role of these cytokines.

Animals↗
PubMed1999

Prophylactic administration of immune lymphokine derived from T cells of Salmonella enteritidis-immune pigs. Protection against Salmonella choleraesuis organ invasion and cecal colonization in weaned pigs.

Experiments involving 132 weaned piglets were conducted to evaluate the efficacy of a Salmonella enteritidis-immune lymphokine (PILK) derived from the T cells of Salmonella enteritidis (SE)-immunized pigs to protect weaned piglets from Salmonella choleraesuis (SC) infection. Fourteen-to-seventeen day-old piglets were weaned and randomly placed into 1 of 5 groups: (1) noninfected controls, (2) PILK 3X noninfected, (3) SC infected controls, (4) PILK 1X SC infected, and (5) PILK 3X SC infected. PILK was given orally either one time (PILK 1X) or three times (PILK 3X) over 14 days. One hour after the first PILK administration on day 0, piglets were orally challenged with 10(7) cfu of SC. Weights were recorded on day 0, day 7, and day 14. On day 14, pigs in groups 3, 4, and 5 were sacrificed and organs and lymph tissue were cultured for the presence of SC. Three replicates of this experiment were pooled and anlayzed. A significant reduction in the number of pigs positive for SC in the liver, lung, and spleen was found in group 5 (PILK 3X) when compared to group 3 (inf. cont. p < 0.001[). The number of SC positive cecal contents was dramatically reduced in group 5 group when compared to group 3, with the PILK 3X group showing 13% positive pigs versus 55.2% in the infected controls (p < 0.05). Weight gain over the 14 day study in the infected PILK 3X group (group 5) was found to be comparable to the gain observed in the group 1 (noninfected controls). The pigs receiving PILK 3X (group 2) with no SC challenge gained significantly more weight than all other groups, including the noninfected controls (group 1 p < 0.05[). The results of these experiments indicate that PILK protects against SC infection in weaned pigs while enhancing performance in the presence of an SC infection.

Animals↗
PubMed1999

Prospective determination of distal colon findings in average-risk patients with proximal colon cancer.

BACKGROUND: Recent guidelines indicate that colonoscopy and sigmoidoscopy are both acceptable options for screening average-risk patients for colorectal cancer. Retrospective studies have found that a majority of patients with cancer proximal to the splenic flexure have a normal screening flexible sigmoidoscopy. METHODS: This was a multicenter, prospective description of colonoscopic findings and family history in consecutive patients with proximal colon cancer. RESULTS: Among 116 prospectively identified average-risk patients with cancer proximal to the splenic flexure, 40 (34.5%) had neoplasia distal to the splenic flexure. The prevalence of patients with adenomas greater than or equal to 1 cm, with only one tubular adenoma less than 1 cm, and with only hyperplastic polyps were 16.4%, 8.6%, and 6.9%, respectively. CONCLUSIONS: Most average-risk patients with cancer proximal to the splenic flexure will have a normal screening flexible sigmoidoscopy. These patients have an unexpectedly high prevalence of large distal adenomas, but the prevalence of both single small tubular adenomas and hyperplastic polyps alone is similar to that expected during screening of the general population. Clinicians and payers should continue to seek methods to improve the cost-effectiveness and availability of screening colonoscopy in average-risk persons.

Adenocarcinoma↗
PubMed1999

Trauma on rural roads: the role of a peripheral hospital.

Road accident trauma is a leading cause of death and serious morbidity among healthy young adults in the developed world. The Irish Republic has the third worst road safety record in the EU. In studying the unique demographics of rural road accidents, our aim was to provide information essential to the future development of trauma care in Ireland. Our figures highlight the inadequacies of data received by the National Roads Authority, illustrate the resource impact of road trauma on a peripheral hospital, and demonstrate the need for similar studies in the rationalisation of trauma care as we approach the next millennium.

Accidents, Traffic↗
PubMed1999

Spatial-specific TGF-beta1 adenoviral expression determines morphogenetic phenotypes in embryonic mouse lung.

The precise spatial-temporal role that expression and activation of transforming growth factor (TGF)-beta plays in mammalian organ morphogenesis remains incompletely understood. Using replication deficient adenoviral vectors containing engineered TGF-beta1 cDNAs, we studied the spatial effects of locally over-expressing either latent or mutated, constitutively active TGF-beta1 protein during embryonic mouse lung branching morphogenesis in culture. Transfer of exogenous genes into lung epithelium was achieved by intra-tracheal micro-injection of recombinant adenovirus, while submerging lungs in virus resulted in gene transfer into the pleura and subjacent mesenchymal cells, as revealed by cytochemical staining for beta-galactosidase. Only lungs transfected with active, but not latent TGF-beta1 gene, showed elevated levels of active TGF-beta. Epithelial over-expression of active, but not latent TGF-beta1, via intra-tracheal micro-injection inhibited lung branching morphogenesis by 36 %. In contrast, lungs submerged with either active or latent TGF-beta1 recombinant virus did not demonstrate an inhibitory effect upon branching. Pulmonary gene regulation was assayed by competitive polymerase chain reaction coupled with reverse transcription. Direct respiratory tract micro-injection of adenovirus over-expressing active TGF-beta1 resulted in a dose-dependent inhibition of epithelial surfactant protein (SP)-C and SP-B mRNA levels by up to 76 % and 70 %, respectively, while in contrast, fibronectin and matrix Gla protein (MGP) mRNA levels remained stable. However, lungs that had been submerged in adenovirus expressing active TGF-beta1 demonstrated a concentration-dependent induction of both fibronectin and MGP mRNA levels up to 4.3- and 4.7-fold respectively in the presence of 1 x 10(11) pfu/ml active TGF-beta1 virus. On the other hand, lungs treated with adenovirus expressing latent TGF-beta1 either by micro-injection or submerging failed to demonstrate any regulatory effect either upon epithelial or mesenchymal gene expression. We conclude that adenovector-mediated over-expression of activated TGF-beta1 in specific spatial compartments results respectively in either inhibition of branching morphogenesis and epithelium-specific gene expression, or in induction of matrix gene expression without affecting morphogenesis or epithelium-specific gene expression, depending on the route of administration. Also, the lack of effect of latent TGF-beta1 over-expression strongly suggests that TGF-beta activation per se provides an important locus of fine regulation of the spatial effects of TGF-beta signaling during embryonic lung branching morphogenesis.

Adenoviridae↗
PubMed1999

Muscle oxygenation trends during constant work rate cycle exercise in men and women.

PURPOSE: To examine the relationship between muscle oxygenation and arteriovenous oxygen difference [(a - v)O2diff)] at four constant rate workloads in healthy men and women and to compare these responses between the genders. METHODS: Nineteen men and 14 women consented to perform an incremental test to identify the lactic acidosis threshold (LAT) and maximal aerobic power (VO2max) and an intermittent constant work rate test at an oxygen uptake corresponding to 40% LAT, 80% LAT, 25% LAT-VO2max, and 50% LAT-VO2max. Each exercise interval was 5 min long followed by 2 min of recovery. Cardiac output was measured by CO2 rebreathing at each workload from which (a - v)O2diff was computed. Tissue absorbency was measured from the vastus lateralis in both the test sessions using near infrared spectroscopy (NIRS). Muscle oxygenation during constant work rate exercise and recovery was expressed as a percentage (%Mox) of the maximum range observed during incremental exercise and recovery. RESULTS: A systematic decrease was observed in %Mox with increasing intensity, followed by a proportional increase during recovery from each exercise bout. Significant inverse relationships were observed between %Mox and (a - v)O2diff in men (r = -0.34) and women (r = -0.31) across the four intensities. Mean %Mox was significantly higher (P < 0.05) in women compared with men, suggesting lesser deoxygenation at the same relative exercise intensity. CONCLUSIONS: %Mox was not an accurate predictor of mixed (a - v)O2diff during exercise because of the low common variance between these two variables, and it is unclear whether the gender difference in %Mox is a true physiological phenomenon or whether it is an artifact of the NIRS technique.

Acidosis, Lactic↗
PubMed1999

Abrogation of cyclin D1 expression predisposes lung cancer cells to serum deprivation-induced apoptosis.

Cyclin D1 antisense (D1AS)-transfected lung epithelial cell lines were serum deprived and then analyzed for three hallmarks of apoptosis: appearance of single-strand DNA breaks, alteration of apoptosis-related protein expression, and induction of chromatin condensation. Single-strand DNA breaks appeared at significant levels 24 h after serum deprivation, whereas induction of chromatin condensation was observed after 72 h. The antioxidants dimethyl sulfoxide, ascorbate, and glutathione, as well as insulin-like growth factor-I, inhibited induction of DNA damage in this assay. Additionally, proliferating cell nuclear antigen expression is completely suppressed in the D1AS cells, indicating a mechanism to explain the reduced capacity for DNA repair. Increased expression of cyclin D1, which is a common lesion in lung cancer, may thus prevent induction of apoptosis in an oxidizing and growth factor-poor environment. Reducing cyclin D1 expression in lung cancer cells by expression of D1AS RNA disrupted these protective pathways.

Antioxidants↗
PubMed1999

ERK activation protects against DNA damage and apoptosis in hyperoxic rat AEC2.

The survival of type 2 alveolar epithelial cells (AEC2) in the lung after hyperoxic injury is regulated by signals from the cellular environment. Keratinocyte growth factor and Matrigel can ameliorate the hallmarks of apoptosis seen in hyperoxic AEC2 after 24-h culture on plastic [S. Buckley, L. Barsky, B. Driscoll, K. Weinberg, K. D. Anderson, and D. Warburton. Am. J. Physiol. 274 (Lung Cell. Mol. Physiol. 18): L714-L720, 1998]. We used the same model of in vivo short-term hyperoxia to characterize the protective effects of substrate attachment. Culture of hyperoxic AEC2 on various biological adhesion substrates showed reduced DNA end labeling in cells grown on all biological substrates compared with growth on plastic. In contrast, the synthetic substrate poly-D-lysine conferred no protection. Hyperoxic AEC2 cultured on laminin showed an increased ratio of expression of Bcl-2 to interleukin-1beta-converting enzyme compared with culture on plastic. Laminin also partially restored hyperoxia-depleted glutathione levels and conferred improved optimal mitochondrial viability as measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Conversely, attachment to the nonphysiological substrate poly-D-lysine afforded no such protection, suggesting that protection against hyperoxia-induced damage may be associated with integrin signaling. Increased activation of extracellular signal-regulated kinase (ERK), as detected by increased ERK tyrosine phosphorylation, was seen in hyperoxic AEC2 as soon as the cells started to attach to laminin and was sustained after 24 h of culture in contrast to that in control AEC2. To confirm that protection against DNA strand breakage and apoptosis was being conferred by ERK activation, the cells were also plated in the presence of 50 microM PD-98059, an inhibitor of the ERK-activating mitogen-activating kinase. Culture for 24 h with PD-98059 abolished the protective effect of laminin. We speculate that after hyperoxic lung injury, signals through the basement membrane confer specific protection against oxygen-induced DNA strand breakage and apoptosis through an ERK activation-dependent pathway.

Animals↗
PubMed1998

Insulin-like growth factor II receptor, transforming growth factor-beta, and Cdk4 expression and the developmental epigenetics of mouse palate morphogenesis and dysmorphogenesis.

The B10/B10.A congenic mouse pair serves as a model for identifying specific genes related to morphogenesis and dysmorphogenesis of the embryonic palate and other organs. The present report describes our initial investigation of the Fraser-Juriloff paradigm, which proposes that susceptibility to malformation results from genetically determined differences in normal developmental patterns. Specifically, we evaluated the relationship between Igf2r gene expression, transforming growth factor-beta (TGF-beta) activation, and cdk4 gene expression. By using in situ hybridization, RNase protection assays, indirect immunofluorescence, Western blots, and bioassays, we show 1) the presence of insulin-like growth factor II (IGF-II), IGF-II receptor (IGF-IIR), IGF-IR, TGF-beta, plasminogen, plasminogen activators [urokinase plasminogen activator (uPA) and tissue plasminogen activator (tPA)], and Cdk4 in developing palates; 2) on embryonic day 14 (E14), which is a critical day for palatal growth, B10.A embryos have 82% greater IGF-IIR mRNA than B10; 3) on E14, B10.A embryonic palates have a 57% greater level of active TGF-beta2 than B10, although the total TGF-beta2 is nearly identical; and 4) on E14, B10 embryonic palates have a 52% greater level of Cdk4 mRNA than B10.A palates, a measure of cell cycle progression. Because cellular activation of latent TGF-beta appears to require binding to the mannose-6-phosphate (M6P) binding site of the IGF-IIR and is plasmin and plasminogen activator dependent, the positive correlation of IGF-IIR levels and active TGF-beta2 levels seems to be key. Thus, the strain variation of TGF-beta2/IGF-IIR-mediated growth inhibition in late G1 phase would appear to account for the slower growth and development of B10.A palates relative to B10. Elevated corticosteroid (CORT) exposure in E14 B10.A embryos significantly increases TGF-beta levels, 87% of which is TGF-beta2, as well as the levels of active TGF-beta, 64% of which is TGF-beta2. Without exogenous CORT, B10.A embryos do not have clefts; hence, we present an outline of pathogenesis: slower growing B10.A embryos have an up-regulation of IGF-IIR, which serves to sequester IGF-II from the growth-promoting IGF-IR and to bind more CORT-up-regulated, latent TGF-beta2 for subsequent plasmin-dependent activation; higher levels of TGF-beta2 signaling down-regulate Cdk4 and result in greater palatal growth inhibition at a critical stage of palatogenesis and, thus, cleft palate. We present an epigenetic model of information processing related to cell proliferation. The model is a dynamical network that uses continuous logic to learn its rules from changing conditions.

Animals↗
PubMed1998

Muscle oxygenation during incremental arm and leg exercise in men and women.

The purpose of this study was to compare the rates of muscle deoxygenation in the exercising muscles during incremental arm cranking and leg cycling exercise in healthy men and women. Fifteen men and 10 women completed arm cranking and leg cycling tests to exhaustion in separate sessions in a counterbalanced order. Cardiorespiratory measurements were monitored using an automated metabolic cart interfaced with an electrocardiogram. Tissue absorbency was recorded continuously at 760 nm and 850 nm during incremental exercise and 6 min of recovery, with a near infrared spectrometer interfaced with a computer. Muscle oxygenation was calculated from the tissue absorbency measurements at 30%, 45%, 60%, 75% and 90% of peak oxygen uptake (VO2) during each exercise mode and is expressed as a percentage of the maximal range observed during exercise and recovery (%Mox). Exponential regression analysis indicated significant inverse relationships (P < 0.01) between %Mox and absolute VO2 during arm cranking and leg cycling in men (multiple R = -0.96 and -0.99, respectively) and women (R = -0.94 and -0.99, respectively). No significant interaction was observed for the %Mox between the two exercise modes and between the two genders. The rate of muscle deoxygenation per litre of VO2 was 31.1% and 26.4% during arm cranking and leg cycling, respectively, in men, and 26.3% and 37.4% respectively, in women. It was concluded that the rate of decline in %Mox for a given increase in VO2 between 30% and 90% of the peak VO2 was independent of exercise mode and gender.

Adaptation, Physiological↗
PubMed1998

Daytime behaviour problems and maternal stress in children with Down's syndrome, their siblings, and non-intellectually disabled and other intellectually disabled peers.

The present study investigates the occurrence of daytime behaviour problems and maternal stress in a group of children with Down's syndrome (DS) compared with a group of their non-intellectually disabled siblings, a group of non-intellectually disabled children from the general population and a group of children with an intellectual disability other than Down's syndrome. The Aberrant Behavior Checklist (ABC) and the Malaise Inventory were completed by the mothers. Associations between daytime behaviour problems and maternal stress were also explored. Overall, the children with DS and the children with other intellectual disabilities showed significantly higher rates of behavioural disturbance on all five of the ABC subscales (Irritability, Lethargy, Stereotypies, Hyperactivity and Inappropriate Speech) and on the Total ABC score. However, the children with other intellectual disabilities also showed significantly higher scores than the children with DS on four of the ABC subscales: Irritability, Lethargy, Stereotypies and Hyperactivity, as well as the Total ABC score. The siblings and children from the general population showed very similar behaviour scores. A number of significant age and sex differences were found in the occurrence of daytime behaviour problems. Maternal stress was significantly higher in the group with other forms of intellectual disability than the other three groups, and a number of significant associations were found between parental ratings of daytime behaviour problems and maternal stress in all four samples. The implications of the findings are discussed, including the need for early assessment to minimize adverse effects on the child's development and on family life.

Adolescent↗
PubMed1998

Inhibition of vascular and epithelial differentiation in murine nitrofen-induced diaphragmatic hernia.

Neonates with congenital diaphragmatic hernia (DH) die of pulmonary hypoplasia and persistent pulmonary hypertension. We used immunohistochemical localization of alpha-smooth muscle actin (alpha-SMA), platelet endothelial cell adhesion molecule (PECAM)-1, thyroid transcription factor (TTF)-1, surfactant protein (SP) A, SP-C, and competitive RT-PCR quantitation of TTF-1, SP-A, SP-C, and alpha-SMA mRNA expression to characterize the epithelial and vascular phenotype of lungs from ICR fetal mice with a nitrofen-induced DH. Nitrofen (25 mg) was gavage fed to pregnant mice on day 8 of gestation. Fetal mice were delivered on day 17. The diaphragm was examined for a defect, and the lungs were either fixed, sectioned, and immunostained or processed for mRNA isolation. In comparison with control lungs, DH lungs showed increased expression of alpha-SMA mRNA, fewer and more muscular arterioles (alpha-SMA), less well-developed capillary networks (PECAM-1), delayed epithelial development marked by a persistence of TTF-1 in the periphery, and decreased SP-A mRNA and SP-A expression. These data suggest that in the murine nitrofen-induced DH, as in human congenital DH, pulmonary insufficiency is due to an inhibition of peripheral pulmonary development including terminal airway and vascular morphogenesis.

Actins↗
PubMed1998

Apoptosis and DNA damage in type 2 alveolar epithelial cells cultured from hyperoxic rats.

Apoptosis is a genetically controlled cellular response to developmental stimuli and environmental insult that culminates in cell death. Sublethal hyperoxic injury in rodents is characterized by a complex but reproducible pattern of lung injury and repair during which the alveolar surface is damaged, denuded, and finally repopulated by type 2 alveolar epithelial cells (AEC2). Postulating that apoptosis might occur in AEC2 after hyperoxic injury, we looked for the hallmarks of apoptosis in AEC2 from hyperoxic rats. A pattern of increased DNA end labeling, DNA laddering, and induction of p53, p21, and Bax proteins, strongly suggestive of apoptosis, was seen in AEC2 cultured from hyperoxic rats when compared with control AEC2. In contrast, significant apoptosis was not detected in freshly isolated AEC2 from oxygen-treated rats. Thus the basal culture conditions appeared to be insufficient to ensure the ex vivo survival of AEC2 damaged in vivo. The oxygen-induced DNA strand breaks were blocked by the addition of 20 ng/ml of keratinocyte growth factor (KGF) to the culture medium from the time of plating and were partly inhibited by Matrigel or a soluble extract of Matrigel. KGF treatment resulted in a partial reduction in the expression of the p21, p53, and Bax proteins but had no effect on DNA laddering. We conclude that sublethal doses of oxygen in vivo cause damage to AEC2, resulting in apoptosis in ex vivo culture, and that KGF can reduce the oxygen-induced DNA damage. We speculate that KGF plays a role as a survival factor in AEC2 by limiting apoptosis in the lung after acute hyperoxic injury.

Animals↗
PubMed1998

Contractility, transforming growth factor-beta, and plasmin in fetal skin fibroblasts: role in scarless wound healing.

The early fetus responds to cutaneous wounds in a fundamentally different way from the adult; fetal wounds heal without scars. Wound contraction is a vital component of wound healing. The cytokine transforming growth factor (TGF)-beta promotes wound contraction and can be activated by the serine protease plasmin. Herein, we explored whether murine skin fibroblast contractile properties, TGF-beta, and plasmin formation are developmentally regulated. Our results showed that early fetal mouse embryonic day 15 skin fibroblasts contracted a collagen gel less, secreted less active and total TGF-beta, and generated less plasmin than either late fetal (embryonic day 17) or adult skin fibroblasts. Furthermore, there was a slight positive correlation between the formation of plasmin and the level of activation of TGF-beta. We conclude that early fetal mouse skin fibroblasts contract a collagen gel and secrete and activate TGF-beta to a lesser extent than do late fetal and adult skin fibroblasts. We speculate that the fetal skin fibroblast undergoes a developmental transition that causes wounds in mouse to contract at or after embryonic day 17. Further, this developmental transition is influenced by growth factor-fibroblast interactions and coincides with the emergence of the skin fibroblast's ability to generate plasmin and activate TGF-beta.

Animals↗
PubMed1998

Process-oriented critical pathways in inpatient psychiatry: our first year.

The critical pathway methodology of assigning and timing staff interventions and expected patient outcomes has developed worldwide recognition, but is less likely to be used in psychiatry than in other medical fields. At St. Mary's in Rochester, New York, an interdisciplinary team adapted the critical pathway concept to meet the needs of an acute inpatient population with relative success. Although staff education needs continue and plans to modify the pathway are in progress, all staff feel that the critical pathway is a viable tool for enhancing patient care and optimizing resources use. Benefits, obstacles, and suggestions are discussed.

Critical Pathways↗
PubMed1997

Physiological and biomechanical responses during treadmill walking with graded loads.

Eleven healthy men [mean (SD) for age, height, body mass and maximum oxygen consumption: 25.1 (3.0) years, 1.79 (0.06) m, 78.2 (10.5) kg and 56.9 (7.1) ml x kg(-1) x min(-1), respectively) completed two treadmill walking tests at their self-selected velocity while bilaterally carrying 15-kg and 20-kg loads (in a boxed container) for 4 min in front of the body. Each handle of the boxed container was fitted with a load cell so as to allow quantification of the load supported by each hand during load carriage. During the tests, oxygen uptake (VO2), heart rate (HR), and blood pressure (BP) were monitored using standardized procedures, and cardiac output (Qc) was measured using the carbon dioxide rebreathing method. Stroke volume (SV), arterio-venous oxygen difference (C(a-v)O2), rate pressure product (RPP) and total peripheral resistance (TPR) were calculated from the above measurements. The results showed that the two extremities sustained approximately 60% to 70% of the total load, with the balance being supported by the body. Significant increases (P < 0.05) in VO2, HR, Qc, and mean BP were observed during both of the load carriage walks compared to unloaded walking. However, SV, C(a-v)O2, RPP and TPR were unchanged (P > 0.05) during load carriage. Although VO2 was significantly higher during the 20-kg load carriage walk, no significant differences were observed between the two loads for any of the cardiovascular responses monitored. Contrary to our hypothesis, these results suggest that increasing the load from 15 kg to 20 kg during treadmill walking does not significantly increase the cardiovascular stress that occurs in healthy subjects.

Adult↗
PubMed1997

Cloning and biochemical characterization of LIMK-2, a protein kinase containing two LIM domains.

We have isolated human and rat clones of the LIM motif-containing protein kinase, termed LIMK-2. LIMK-2 is related to the neuronally expressed LIM-kinase, whose hemizygous deletion appears to result in cognitive impairment in patients with Williams syndrome. The hallmark of this protein family is the presence of 1 or 2-terminal LIM motifs and an atypical C-terminal protein kinase domain. LIMK-2 mRNA was detected by Northern blot analysis in human tissues, most abundantly in placenta, lung, liver, and pancreas, and also in a variety of cell lines including neuronal, glioblastoma, and mammary carcinoma lines. The LIMK-2 transcript was also induced upon neuroectodermal differentiation of mouse P19 embryonal carcinoma cells. A 65 kDa recombinant LIMK-2 protein was identified in 293 cells stably transfected with a LIMK-2 expression vector. An in vitro kinase assay demonstrates LIMK-2 is autophosphorylated and exhibits serine/threonine kinase activity towards the exogenous substrate MBP. The endogenous 65 kDa LIMK-2 protein was detected in a variety of cell lines, and coprecipitates with a 140 kDa tyrosine phosphorylated protein, but was not itself tyrosine phosphorylated. At the subcellular level, LIMK-2 is localized in both the nucleus and in a Triton X-100 soluble fraction.

Amino Acid Sequence↗