Consensus Statement of the IAP - Neurodevelopmental Chapter On Neurodevelopmental Disorders Habilitation Process: Strategic Plan for Prevention, Early Detection and Early Intervention.

JUSTIFICATION: Neurodevelopmental disorders, as per DSM-V, are described as a group of conditions with onset in the development period of childhood. There is a need to distinguish the process of habilitation and rehabilitation, especially in a developing country like India, and define the roles of all stakeholders to reduce the burden of neurodevelopmental disorders. PROCESS: Subject experts and members of Indian Academy of Pediatrics (IAP) Chapter of Neurodevelopmental Pediatrics, who reviewed the literature on the topic, developed key questions and prepared the first draft on guidelines. The guidelines were then discussed by the whole group through online meetings, and the contentious issues were discussed until a general consensus was arrived at. Following this, the final guidelines were drafted by the writing group and approved by all contributors. OBJECTIVES: These guidelines aim to provide practical clinical guidelines for pediatricians on the prevention, early diagnosis and management of neurodevelopmental disorders (NDDs) in the Indian settings. It also defines the roles of developmental pediatricians and development nurse counselor. STATEMENT: There is a need for nationwide studies with representative sampling on epidemiology of babies with early NDD in the first 1000 days in India. Specific learning disability (SLD) has been documented as the most common NDD after 6 years in India, and special efforts should be made to establish the epidemiology of infants and toddlers at risk for SLD, where ever measures are available. Preconception counseling as part of focusing on first 1000 days; Promoting efforts to organize systematic training programs in Newborn Resuscitation Program (NRP); Lactation management; Developmental follow-up and Early stimulation for SNCU/ NICU graduates; Risk stratification of NICU graduates, Newborn Screening; Counseling parents; Screening for developmental delay by trained professionals using simple validated Indian screening tools at 4, 8, 12, 18 and 24 months; Holistic assessment of 10 NDDs at child developmental clinics (CDCs) / district early intervention centre (DEICs) by multidisciplinary team members; Confirmation of diagnosis by developmental pediatrician/developmental neurologist/child psychiatrist using clinical/diagnostic tools; Providing parent guided low intensity multimodal therapies before 3 years age as a center-based or home-based or community-based rehabilitation; Developmental pediatrician to seek guidance of pediatric neurologist, geneticist, child psychiatrist, physiatrist, and other specialists, when necessary; and Need to promote ongoing academic programs in clinical child development for capacity building of community based therapies, are the chief recommendations.

Goniometric Assessment of Muscle Tone of Preterm Infants and Impact of Gestational Age on Its Maturation in Indian Setting.

CONTEXT: The normative data on muscle tone of preterm infants by goniometric assessment in Indian setting are scarce. AIM: The aim of this study it to provide a normative objective data of muscle tone of preterm infants by gestation using goniometer. SETTINGS AND DESIGN: This was a prospective, observational study including preterm infants admitted in a tertiary care hospital from North India. SUBJECTS AND METHODS: The objective dimension of muscle tone assessment of 204 healthy preterm infants was done; 61 infants completed follow-up till 40 weeks' postconceptional age (PCA) and were compared to term infants. STATISTICAL ANALYSIS USED: SPSS (version 16.0) was used. The intergroup comparison was done through ANOVA, and the localization of differences between the groups was determined through multiple comparisons by post hoc test. RESULTS: Mean gestational age was 34.3 ± 1.7 weeks. Angles were as follows: adductor = 100.1 ± 8.7, popliteal = 118.9 ± 8.6, dorsiflexion = 39.0 ± 9.0, heel to ear = 121.90 ± 7.90, wrist flexion = 46.0 ± 10.2, and arm recoil = 122.2° ± 16.6°. The evolution of muscle tone as indicated by heel-to-ear angle shows progressive maturation from 32 weeks' gestation while adductor angle, popliteal angle, and arm recoil mature predominantly after 36 weeks' gestation. Comparison of preterm infants to term at 40 weeks' PCA demonstrated significantly less tone in all except posture and heel to ear. CONCLUSIONS: Goniometric assessment provides a objective normative data of muscle tone for preterm infants. Maturation of heel to ear and posture evolves from 32 weeks onwards and are the earliest neurologic marker to mature in preterm infants independent of the gestational age at birth.

Homocysteine Metabolism and Hematological Parameters in Early Stage of Phenytoin Treated Epileptic Children.

BACKGROUND: Long-term antiepileptic drug (AED) therapy has been associated with metabolic consequences that lead to an increase in risk of atherosclerosis in patients with epilepsy. Earlier published studies showed conflicting results about the levels of hematological parameters, serum homocysteine, folate, and vitamin B12, in epileptics treated with phenytoin monotherapy. Therefore, we evaluated homocysteine metabolism and hematological parameters in early stage of phenytoin treated epileptic children. METHODS: A total of 64 newly diagnosed epileptic children with mean age 10.09 ± 2.56 years were enrolled at the start of study. However, after 3 months follow up, the final total sample size was only 50 epileptic children. Fourteen children dropped out of study due to poor follow up. Serum homocysteine levels were measured by enzyme immunoassay method. Serum folate and vitamin B12 levels were estimated by Competitive Chemiluminescent Enzyme Immunoassay method. Hematological parameters were analysed by an automated hematology analyzer (Cell counter), Sysmex XT-1800i, using commercially available reagents. RESULTS: In our study the anthropometric and hematological parameters did not show any significant difference after phenytoin monotherapy as compared to before therapy in epileptic children. The serum homocysteine level in epileptic children was found to be significantly increased after phenytoin (PHT) monotherapy as compared to before therapy. Moreover, a highly significant decrease was observed in the serum folate and vitamin B12 levels after phenytoin monotherapy as compared to before therapy in epileptic children. CONCLUSIONS: Phenytoin monotherapy may cause a significant increase in the levels of serum homocysteine and a significant decrease in the serum folate and vitamin B12 levels in children with epilepsy, and the significant changes in above mentioned parameters occur early in the course of treatment. This could be responsible for a higher prevalence of cardiovascular incidents in epileptic children taking phenytoin monotherapy. Therefore, it may be useful to do early screening and treatment of increased serum homocysteine levels in epileptic children under phenytoin monotherapy to prevent atherosclerosis and its complications. Hematological parameters should also be strictly monitored regularly in individuals administered with PHT monotherapy. If there are persistent alterations, the administration of the drugs should be discontinued.

Joint Involvement in Children with Celiac Disease.

OBJECTIVE: To determine early joint involvement as detected by ultrasonography in children with newly diagnosed celiac disease, and in children with celiac disease on gluten-free diet for more than 6 months. METHODS: Cross-sectional comparative study evaluating joint abnormalities by ultrasonography. RESULTS: Ultrasonography showed abnormalities in 19 out of 60 (31.7%) children with newly diagnosed celiac disease as compared to 2 (3.3%) out of 60 in those on a gluten-free diet for more than 6 months. CONCLUSION: Subclinical synovitis as detected by ultrasound is a frequent finding in newly diagnosed children with celiac disease.

Serum Homocysteine, Folate, and Vitamin B12 Levels in Carbamazepine Treated Epileptic Children.

BACKGROUND: Antiepileptic drugs (AEDs) have been associated with metabolic consequences that lead to an increase in risk of atherosclerosis in patients with epilepsy. Therefore, we evaluated whether differences exist in homocysteine, folate, and vitamin B12 levels in children receiving carbamazepine (CBZ) monotherapy. METHODS: A total of 58 newly diagnosed epileptic children with ages ranging from 2 to 15 years were enrolled at the start of study. However, after 3 months follow up, the final total sample size was only 50 epileptic children. Eight children dropped out of the study due to poor follow up. Serum homocysteine levels were measured by enzyme immunoassay method. Serum folate and vitamin B12 levels were estimated by Competitive Chemiluminescent Enzyme Immunoassay method. RESULTS: The serum homocysteine level in epileptic children was found to be significantly increased after carbamazepine (CBZ) monotherapy as compared to before therapy. Moreover, a highly significant decrease was observed in the serum folate and vitamin B12 levels, after carbamazepine monotherapy as compared to before therapy in epileptic children. CONCLUSIONS: Carbamazepine monotherapy may cause a significant increase in the levels of homocysteine and a significant decrease in the levels of serum folate and vitamin B12 in children with epilepsy, significant changes in above mentioned parameters occurring early in the course of treatment. The atherogenic effect of increased serum homocysteine level is well established, and patients under carbamazepine monotherapy should be monitored for possible atherogenic effects. Therefore, it may be useful to measure serum homocysteine, folate, and vitamin B12 concentrations routinely in children with epilepsy taking carbamazepine monotherapy and be treated when their levels are found to be disturbed.

Evaluate the Effect of Valproate Monotherapy on the Serum Homocysteine, Folate and Vitamin B12 Levels in Epileptic Children.

BACKGROUND: The data regarding Valproate and its influence on serum folate and homocysteine levels are conflicting. The aim of this study was to evaluate whether differences exist in homocysteine, folate, and vitamin B12 levels in children receiving Valproate. METHODS: A total of 55 newly diagnosed epileptic children with ages ranging from 2 to 15 years were enrolled at the start of study but after 3 months follow up, the total sample size finally was only 50 epileptic children. 5 children dropped out of study due to poor follow up. 50 age and gender matched healthy control subjects were also studied on enrollment at the start of study. Serum homocysteine levels were analyzed by enzyme immunoassay method using the kits provided by Axis-Shield Diagnostics Ltd (Dundee DD2 1XA, United Kingdom). Serum folate and serum vitamin B12 were estimated by Competitive Chemiluminescent Enzyme Immunoassay method. RESULTS: The serum homocysteine level in epileptic children was found to be significantly increased after Valproate monotherapy as compared to before therapy. Moreover, a highly significant decrease was observed in the levels of serum folate in epileptic children after Valproate monotherapy as compared to before therapy. But a non significant difference was observed in serum vitamin B12 levels in epileptic children before and after Valproate monotherapy. CONCLUSIONS: Thus, we conclude that there is a significant increase in the levels of homocysteine and a significant decrease in the concentration of serum folate while vitamin B12 decreases non-significantly after Valproate monotherapy. The atherogenic effect of increased serum homocysteine level is well established; the patients under Valproate monotherapy should be monitored for possible atherogenic effects. Considering the above observation and results of children undergoing Valproate monotherapy, these children should be screened for levels of serum homocysteine, folate, and vitamin B12 and treated when their levels are found to be disturbed.

Colonic motor dysfunction in human diabetes is associated with enteric neuronal loss and increased oxidative stress.

BACKGROUND: Gastrointestinal dysfunction is very common in diabetic patients. We assessed the changes in the colonic enteric nervous system using colectomy specimens and intestinal biopsies from diabetic subjects and age-matched controls. METHODS: In control and diabetic colons, we determined the total ganglion area (hematoxylin-eosin staining), changes in neuronal markers-protein gene product 9.5, peripherin, neuronal nitric oxide synthase (nNOS), neuropeptide Y (NPY), choline acetyl transferase (ChAT) and vasoactive intestinal peptide (by immunostaining), apoptosis (cleaved caspase-3 staining) and reduced glutathione levels. Superoxide dismutase mRNA was determined in enteric ganglia isolated by laser capture micro dissection. Isometric muscle recording was used to assess contraction and relaxation responses of colonic circular muscle strips. Apoptosis in enteric neurons under hyperglycemia in vitro was determined by cleaved caspase-3 Western blotting and protective effects of lipoic acid were evaluated. KEY RESULTS: Diabetic subjects had higher incidence of lower gastrointestinal symptoms like constipation and diarrhea at baseline prior to surgery. Diabetic ganglia displayed significant decrease in ganglion size due to enhanced apoptosis and loss of peripherin, nNOS, NPY, and ChAT neurons. Reduced glutathione levels in the diabetic colon (HbA1C > 7%) were significantly less than the control, indicating increased oxidative stress. Colonic circular muscle strips from diabetic subjects showed impaired contraction and relaxation responses compared with the healthy controls. Hyperglycemia-induced cleaved caspase-3 in enteric neurons was reversed by lipoic acid. CONCLUSIONS & INFERENCES: Our data demonstrate loss of enteric neurons in the colon due to increased oxidative stress and apoptosis which may cause the motility disturbances seen in human diabetes. Antioxidants may be of therapeutic value for preventing motility disorders in diabetes.

Hutchinson-Gilford progeria syndrome.

Progeria is a rare genetic disorder characterized by premature aging, involving the skin, bones, heart, and blood vessels. We report a 4-year-old boy who presented with clinical manifestations of progeria. He had characteristic facies, prominent eyes, scalp and leg veins, senile look, loss of scalp hair, eyebrows and eyelashes, stunted growth, and sclerodermatous changes. The present case is reported due to its rarity.

Asthma control test and peak expiratory flow rate: independent pediatric asthma management tools.

BACKGROUND: Management of asthma reflects the complexity of the pathogenesis. According to current National Heart Lung Blood Institute (NHLBI) guidelines, asthma control can be assessed using the validated asthma control test, measures of airway function, and overall assessment of risk and quality of life. We hypothesized that the asthma control test and measures of airway function are independent tools in asthma management. We also studied whether the presence of nasal symptoms is correlated to these measures. METHODS: Serial visits (n = 45) to a pediatric respiratory clinic in an underserved area of San Diego County with a predominantly Hispanic population were reviewed. Patients were included if they were able to perform airway function tests and had more than one provider visit. Patients with other major diseases were excluded. We determined whether uncontrolled asthmatics, defined as an Asthma Control test (ACT) score of 19 or less, had lower % predicted peak expiratory flow Measurements as a group compared to those with higher scores. In addition, the individual ACT and airway function results were analyzed. Patients with and without nasal symptoms at the time of presentation were sub-analyzed to determine differences in ACT and peak flow measurements. RESULTS: Based on n = 45 physician visits, the mean ACT score was 21 +/- 3.3 (range 12-25) and the mean peak expiratory flow rate (PEFR) was 87.4% +/- 11 (range 65-109%). Patients with ACT scores < or = to 19 or lower (< or = 90%) PEFRs were determined not to have more nasal symptoms. The measures of ACT and peak expiratory flow were independent and not correlated. CONCLUSIONS: Our study indicates that ACT and PEFR are distinct parameters used to manage patients in a pediatric outreach asthma clinic.

Cloning and characterization of a new intestinal inflammation-associated colonic epithelial Ste20-related protein kinase isoform.

Intestinal epithelial cells respond to inflammatory extracellular stimuli by activating mitogen activated protein kinase (MAPK) signaling, which mediates numerous pathophysiological effects, including intestinal inflammation. Here, we show that a novel isoform of SPS1-related proline alanine-rich kinase (SPAK/STE20) is involved in this inflammatory signaling cascade. We cloned and characterized a SPAK isoform from inflamed colon tissue, and found that this SPAK isoform lacked the characteristic PAPA box and alphaF loop found in SPAK. Based on genomic sequence analysis the lack of PAPA box and alphaF loop in colonic SPAK isoform was the result of specific splicing that affect exon 1 and exon 7 of the SPAK gene. The SPAK isoform was found in inflamed and non-inflamed colon tissues as well as Caco2-BBE cells, but not in other tissues, such as liver, spleen, brain, prostate and kidney. In vitro analyses demonstrated that the SPAK isoform possessed serine/threonine kinase activity, which could be abolished by a substitution of isoleucine for the lysine at position 34 in the ATP-binding site of the catalytic domain. Treatment of Caco2-BBE cells with the pro-inflammatory cytokine, interferon gamma, induced expression of the SPAK isoform. Over-expression of the SPAK isoform in Caco2-BBE cells led to nuclear translocation of an N-terminal fragment of the SPAK isoform, as well as activation of p38 MAP kinase signaling cascades and increased intestinal barrier permeability. These findings collectively suggest that pro-inflammatory cytokine signaling may induce expression of this novel SPAK isoform in intestinal epithelia, triggering the signaling cascades that govern intestinal inflammation.

Glial cell line-derived neurotrophic factor-mediated enteric neuronal survival involves glycogen synthase kinase-3beta phosphorylation and coupling with 14-3-3.

Glial cell line-derived neurotrophic factor (GDNF) promotes the growth and survival of enteric neurons, but the mechanisms involved are poorly understood. GDNF is known to promote the survival of enteric neurons through activation of the PI3-Kinase/Akt signaling pathway. We investigated the role of glycogen synthase kinase-3beta (GSK-3beta) in enteric neuronal survival, and the ability of GDNF to regulate the activity of GSK-3beta using primary rat embryonic enteric neurons. GDNF, through activation of the PI3-kinase pathway enhanced the phosphorylation of GSK-3beta at its N-terminal serine-9 residue, and promoted the association of GSK-3beta with 14-3-3. Transfection of a constitutively active S9A-GSK-3beta mutant prevented the survival effects of GDNF, whereas a dominant negative GSK-3beta construct prevented GDNF withdrawal-induced cell death. Increased GSK-3beta activity was associated with an increase in tau phosphorylation. Thus, GDNF promotes enteric neuronal survival by modulating GSK-3beta and its downstream target tau. Inhibitors of GSK-3beta activity may have therapeutic potential in improving enteric neuronal survival.

TNF-alpha upregulates adenosine 2b (A2b) receptor expression and signaling in intestinal epithelial cells: a basis for A2bR overexpression in colitis.

Adenosine is an endogenous signaling molecule upregulated during inflammatory conditions. Acting through the A2b receptor (A2bR), the predominant adenosine receptor in human colonic epithelia, adenosine has been directly implicated in immune and inflammatory responses in the intestine. Little is known about expression and regulation of A2bR during inflammation. Tumor necrosis factor alpha (TNF-alpha) is highly upregulated during chronic and acute inflammatory diseases. This study examined the expression of A2bR during colitis and studied effects of TNF-alpha on A2bR expression, signaling and function. Results demonstrated that A2bR expression increases during active colitis. TNF-alpha pretreatment of intestinal epithelial cells increased A2bR messenger RNA and protein expression. TNF-alpha significantly increased adenosine-induced membrane recruitment of A2bR and cyclic adenosine monophosphate downstream signaling. Further, TNF-alpha potentiated adenosine-induced shortcircuit current and fibronectin secretion. In conclusion, we demonstrated that TNF-alpha is an important regulator of A2bR, and during inflammation, upregulation of TNF-alpha may potentiate adenosine-mediated responses.

Interaction of bacteria and bacterial toxins with intestinal epithelial cells.

The epithelium of the intestinal tract is a key barrier between the external environment and the internal body environment. Intestinal epithelial cells are targets for luminal bacteria and viruses and must discriminate between pathogenic and nonpathogenic commensal organisms. Pathogenic bacteria and their secreted products influence epithelial cell function and induce diarrhea by numerous mechanisms that range from an effect on epithelial cell-cell associations to intracellular signal transduction pathways. These effects lead to an inflammatory response and an influx of neutrophils into the epithelium. Infiltrating neutrophils, in turn, signal to epithelial cells, induce a secretory response, and perpetuate the diarrhea. Conversely, commensal bacteria have the ability to suppress inflammatory responses by inhibiting specific intracellular signal transduction pathways. Some of these diverse host pathogenic responses are addressed in this review.

CD98-mediated links between amino acid transport and beta 1 integrin distribution in polarized columnar epithelia.

In non-polarized cells, CD98 has been shown to both influence beta(1) integrins and heterodimerize with LAT-2, which confers amino acid transport capability on the LAT-2/CD98 heterodimer. Since LAT-2 is most heavily expressed in intestine and CD98 associates with the beta(1) integrin splice form selectively found in such epithelia, we investigated the relationship and polarity of these proteins using the intestinal epithelial model Caco2-BBE. CD98 was found to selectively coimmunoprecipitate with both LAT-2 and beta(1) integrin, and, logically, all three proteins were polarized to the same (basolateral) domain. Furthermore, expression of CD98 in polarized epithelia lacking human CD98 (MDCK cells) disrupted beta(1) integrin surface distribution and cytoskeletal architecture, suggesting that CD98 can influence integrin function. Expression of a CD98 mutant lacking the specific residues conferring LAT-2 binding similarly affected cells, confirming that the latter effect was not due to LAT-2 sequestration. Use of CD98 truncation mutants suggest that a 10-amino acid domain located at the putative cytoplasmic tail/transmembrane domain interface was necessary and sufficient to induce the phenotype change. We conclude that the CD98/LAT-2 amino acid transporter is polarized to the same domain on which beta(1) integrin resides. CD98 appears to associate with beta(1) integrin and, in doing so, may influence its function as revealed by disruption of the outside-in signaling that confers cytoskeletal organization. Furthermore, such findings suggest a link between classic transport events and a critical element of barrier function: integrin-mediated influences on cytoskeletal organization.

Colonic epithelial hPepT1 expression occurs in inflammatory bowel disease: transport of bacterial peptides influences expression of MHC class 1 molecules.

BACKGROUND & AIMS: hPepT1 is an intestinal epithelial apical membrane transporter responsible for uptake of di/tripeptides (including bacterial derived proinflammatory n-formyl peptides). hPepT1 expression normally has a strict axial gradient-highest in the proximal small intestine with no expression in the colon. METHODS: Small intestinal-like cells (Caco2-BBE), and colonic-like cells (HT29-Cl.19A), and colonic mucosa from diseased and control patients were used in the present study. RESULTS: hPepT1 expression occurs aberrantly in the colon with chronic ulcerative colitis (6 patients) and Crohn's disease (4 patients), but not in normal colon (4 patients) or colon with microscopic colitis (4 patients). To model expression of hPepT1 by colonic-like cells in inflamed states, we stably transfected HT29-Cl.19A cells with a modified hPepT1 tagged on the N-terminus with green fluorescence protein. Analysis of transfected cells revealed that: GFP-hPepT1 protein, like the natural protein, is targeted to the apical plasma membrane. In addition, the tagged protein retains the capability of di/tripeptide absorption, and the expression of the tagged protein by HT29-Cl.19A cells permits absorption of N-formyl-methionyl-leucyl-phenylalanine (fMLP), as occurs in hPepT1 expressing Caco2-BBE cells. fMLP uptake by colonic cells expressing GFP-hPepT1 specifically enhances major histocompatibility complex class I surface expression. CONCLUSIONS: These data collectively indicate that, in some states of chronic inflammation, hPepT1 may be anomolously expressed in the colon. Further, transport of fMLP by hPepT1 potentially stimulates expression of key accessory immune molecule, MHC-1.

Neutrophil-epithelial crosstalk at the intestinal lumenal surface mediated by reciprocal secretion of adenosine and IL-6.

Adenosine is formed in the intestinal lumen during active inflammation from neutrophil-derived 5' AMP. Using intestinal epithelial cell line T84, we studied the effect of adenosine on the secretion of IL-6, a proinflammatory cytokine involved in neutrophil degranulation and lymphocyte differentiation. Stimulation of T84 monolayers with either apical or basolateral adenosine induces A2b receptor-mediated increase in IL-6 secretion, which is polarized to the apical (luminal) compartment. In addition, Salmonella typhimurium, TNF-alpha, and forskolin, known inducers of IL-6 secretion in intestinal epithelial cells, also stimulate IL-6 secretion into the apical compartment. We show that IL6 promoter induction by adenosine occurs through cAMP-mediated activation of nuclear cAMP-responsive element-binding protein (CREB). We also show that IL-6 released in the luminal (apical) compartment achieves a sufficient concentration to activate neutrophils (from which the adenosine signal originates), since such IL-6 is found to induce an intracellular [Ca(++)] flux in neutrophils. We conclude that adenosine released in the intestinal lumen during active inflammation may induce IL-6 secretion, which is mediated by cAMP/CREB activation and occurs in an apically polarized fashion. This would allow sequential activation of neutrophil degranulation in the lumen -- a flow of events that would, in an epithelium-dependent fashion, enhance microbicidal activity of neutrophils as they arrive in the intestinal lumen.

Negative regulation of epithelium-neutrophil interactions via activation of CD44.

Polymorphonuclear neutrophil (PMN) migration across epithelia is a common feature of active inflammation. Given the suggested role of carbohydrates in this process, we examined the receptor CD44. The standard CD44 isoform was expressed at the cell surface of PMN. PMN migration across model polarized intestinal epithelia was reduced (by 60%) if the CD44 receptor was activated by either a specific antibody (clone IM7) or the natural soluble ligand, hyaluronic acid. This inhibitory effect following receptor activation occurred with both basolateral-to-apical- and apical-to-basolateral-directed migration. The anti-CD44 antibody similarly reduced PMN migration through filters in the absence of epithelia, while preincubation of the antibody with the epithelium did not alter subsequent PMN transepithelial migration. These data suggest that PMN, rather than epithelial, CD44 is responsible for these effects. A similar inhibitory effect of anti-CD44 antibody was also observed on migration of intraepithelial lymphocytes. The molecular mechanism involved in such negative signaling following CD44 activation may include modulation of outside-in cell signaling. While neither the anti-CD44 antibody nor CD44 ligand affected PMN mobilization of intracellular Ca(2+), both led to increased adenylate cyclase activity, an inhibitory signal for PMN migration. Together, these results suggest that CD44 of PMN may potentially serve as a negative regulator of leukocyte migration across biological surfaces such as columnar epithelia.