Decreased morning serum cortisol levels in children with asthma treated with inhaled fluticasone propionate

OBJECTIVE

In an observational long-term study, we followed 62 children (37 males, 25 females; mean age: 11.6 +/- 2.9 years) with moderate-to-severe asthma for 2 years and studied the effects of fluticasone propionate (176-1320 microg/day) on the function of the hypothalamic-pituitary-adrenal axis.

STUDY DESIGN

Morning cortisol levels were monitored after patients had been on fluticasone for a mean of 8.0 +/- 5.2 months. Patients who had abnormal low morning cortisol levels (<5.5 microg/dL) were then switched either to lower fluticasone dosage or to other inhaled steroid formulation. Exact methods based on the binomial distribution were used to construct a 95% confidence interval for the true proportion of abnormal readings among those treated, and the Wilcoxon signed rank test was used to test for a significant difference between cortisol levels taken before and after the switch.

RESULTS

Twenty-two patients (36%) had abnormal morning cortisol levels while on fluticasone. Of the patients on a low dose (176 microg/day), 17% had abnormal values, whereas 43% of patients on a high dose (> or =880 microg/day) were abnormal. Patients with abnormal results (17/22) had their morning cortisol levels repeated 3 months after the switch. Thirteen of these patients (77%) had normal levels. A stratified analysis of the difference in morning cortisol levels before and after the switch showed significant increase in morning cortisol levels in the group receiving 440 microg/day or less of fluticasone (median difference: 5.25; confidence interval: 3.60-8.15), as well as in the group receiving 440 microg/day or more (median difference: 3.85; confidence interval: 1.00-7.60).

CONCLUSION

Inhaled fluticasone, even at conventional doses, may have greater effects on the adrenal function than previously recognized, but the clinical significance of this suppression still remains to be established.

Chronic aspiration without gastroesophageal reflux as a cause of chronic respiratory symptoms in neurologically normal infants

OBJECTIVE

To describe 13 neurologically normal infants with chronic respiratory symptoms who had swallowing dysfunction with silent chronic aspiration without gastroesophageal reflux (GER) as the cause of their respiratory symptoms.

BACKGROUND

Infants with neurologic disorders and infants with GER are known to have chronic respiratory symptoms. Isolated swallowing dysfunction and aspiration without GER in neurologically normal infants have not been widely reported.

DESIGN

Retrospective chart review.

SETTING

A tertiary pulmonary-care center at a children's hospital.

PATIENTS

One hundred twelve otherwise healthy infants referred for respiratory symptoms who underwent esophageal pH studies and videofluoroscopic swallow studies (VSSs).

METHODS

The records of infants referred between January 1997 and December 1999 to the Department of Pediatric Pulmonology who underwent 24-h esophageal pH monitoring and VSS as part of an evaluation for recurrent stridor and/or wheezing were reviewed. Significant GER was diagnosed if the percentage of time with esophageal pH < 4 was > 6%. Infants included in the study presented with recurrent respiratory symptoms, were born at term, were neurologically normal, had normal results of esophageal pH studies, but had abnormal results of VSSs (n = 13).

RESULTS

All 13 infants presented with a variety of recurrent respiratory symptoms including wheezing and intermittent stridor. Ten of 13 infants had spitting and/or choking episodes with feeding. The mean (+/- SD) age at the onset of symptoms was 2.0 +/- 1.6 months, and the mean age at VSS was 5.9 +/- 3.4 months. All 13 infants had normal results of 24-h esophageal pH studies but had abnormal results for VSSs. All infants had evidence of swallowing dysfunction and direct silent aspiration of liquids with thin consistency. Six infants also were aspirating liquids with thick and/or semi-thick consistencies. None of the infants had evidence of structural anomalies on esophagograms. Nine infants were treated with thickened food, and in four infants oral feedings were stopped. Three of these infants required nasojejunal feeding, and one infant required gastrostomy tube feeding. VSSs were repeated every 3 months. In all infants, swallowing dysfunction resolved within 3 to 9 months. All infants tolerated the resumption of oral feeding. Videofluoroscopic documentation of the resolution of aspiration was followed by the resolution of respiratory symptoms in all infants.

CONCLUSION

There is a subgroup of otherwise healthy infants, presenting with wheeze and/or stridor, who have isolated swallowing dysfunction and silent aspiration as the cause of their respiratory symptoms.

Regulation of human papillomavirus type 1 replication by the viral E2 protein

The E1 and E2 proteins encoded by papillomaviruses are required for viral replication. Earlier studies have shown that the viral E2 protein plays an important role in replication by targeting the E1 helicase to the origin of replication (ori). We have previously shown that the E1 protein of human papillomavirus (HPV) type 1 is sufficient for the in vivo replication of ori plasmids, although the E2 protein stimulates replication. In this study, we have further analyzed the role of the E2 protein in HPV-1 replication. The optimal ori of HPV-1 contains one putative E1 binding site (E1BS) and two putative E2 binding sites, E2BS-3 and E2BS-4. Plasmid pori171, containing the optimal ori, replicates to much higher levels than plasmid pori312, which includes an additional upstream E2 binding site, E2BS-2, located 75 nucleotides upstream of E2BS-3. To study the possible role of E2BS-2 and other upstream sequences in E2-dependent downregulation of replication, transient replication analysis was done in the presence of increasing levels of the E2 protein. Interestingly, inhibition of pori312 replication was more severe at higher levels of E2, suggesting that this protein may also negatively regulate HPV-1 replication. Deletion of sequences from pori312 containing an additional putative E2BS, E2BS-2A, relieved the repression of replication to a significant extent, while replacement of E2BS-2 with a different sequence of the same length had a modest effect. These results suggest that E2BS-2A plays a major and E2BS-2 a minor role in the negative regulation of HPV-1 replication at high E2 levels. Electrophoretic mobility-shift assays showed that the purified E2 protein bound with high affinity to E2BS-3 and weakly to the other putative E2BSs located within the viral long control region. EMSA using various ori fragments showed the formation of multiple E2-DNA complexes which likely represent binding of E2 to multiple E2BSs present within the HPV-1 ori. Our data are consistent with the assembly of ori-protein complexes at high E2 levels that are impaired for replication and further suggest that E2 may regulate HPV-1 replication by a mechanism involving interaction between the E2 protein bound to E2BSs at a distance.

Urinary leukotriene E(4) excretion during the first month of life and subsequent bronchopulmonary dysplasia in premature infants

BACKGROUND

Inflammation plays an important role in the pathogenesis of bronchopulmonary dysplasia (BPD), but the exact nature of this inflammatory process is incompletely understood. Older infants with established BPD have higher levels of urinary leukotriene E(4) (LTE(4)) compared to healthy infants of the same age. This suggests that cysteinyl leukotrienes may play a role in the abnormalities seen in BPD.

OBJECTIVES

To measure urinary LTE(4) levels during the first month of life in premature infants, and to determine whether there are significant differences in premature infants who develop BPD, as compared to those who do not develop BPD.

DESIGN

Prospective, blinded, controlled study.

SETTING

Neonatal ICUs of a tertiary-care university hospital.

METHODS

Thirty-seven premature infants (< 33 weeks of gestational age) were enrolled prospectively at birth. Urinary LTE(4) levels were measured blinded, using a standard radioimmunoassay technique at 2 days, 7 days, and 28 days of life. At 1 month of age, infants were classified as with or without BPD, based on need for supplemental oxygen, and characteristic chest radiographs. Clinical features and urinary LTE(4) were compared between the two groups.

RESULTS

Mean +/- SD gestational age was 29 +/- 2.6 weeks. None of the infants had a family history of asthma. Thirteen of 37 infants were classified as having BPD at 28 days after birth. Mean gestational age in infants who developed BPD was 27 +/- 2.4 weeks, compared to 30 +/- 2 weeks in infants who did not develop BPD (p < 0.05). In infants with BPD, mean urinary LTE(4) levels of urinary creatinine were 1,762 +/- 2,003 pg/mg, 1,236 +/- 992 pg/mg, and 5,541 +/- 5,146 pg/mg at days 2, 7, and 28, respectively, compared to 1,304 +/- 1,195 pg/mg, 1,158 +/- 1,133 pg/mg, and 2,800 +/- 2,080 pg/mg in infants without BPD. LTE(4) levels at 2 days, 7 days, and 28 days did not correlate with the subsequent development of BPD. LTE(4) levels at day 28 were significantly higher than LTE(4) levels at day 2 and day 7 in both groups, even after correcting for gestational age or birth weight (p < 0.05). There was significant inverse correlation between LTE(4) levels at day 2 with gestational age and birth weight (p < 0.05). All 13 infants with BPD received steroid pulses, compared to 3 of 26 infants without BPD. Gestational age and use of postnatal steroid pulses, diuretics, and theophylline (for apnea of prematurity) were significantly associated with each other and with the subsequent development of BPD.

CONCLUSION

Urinary LTE(4) levels measured on the second day of life in very-low-birth-weight infants inversely correlate with gestational age and birth weight. Urinary LTE(4) levels may reflect lung injury and/or inflammation in premature infants, not necessarily related to BPD as it is presently defined.

Evaluation of the wheezy infant

BACKGROUND

The infant with persistent or recurrent wheezing during the first 2 years of life poses a diagnostic dilemma, which can be a source of anxiety to both physicians and parents. A suggested diagnostic approach to the causes of infantile wheezing is outlined.

OBJECTIVES

1. To review the physiologic considerations of the infant's airways that predispose to wheezing. 2. To discuss the key physical findings, family history, and risk factors associated with wheezing in infants. 3. To develop a rational approach to the differential diagnosis and management of infantile wheezing.

DATA SOURCES

The MEDLINE database as well as our clinical experience pertaining to infantile wheezing.

CONCLUSIONS

This review discusses the diagnostic evaluation and treatment of the wheezing infant. We suggest that infant pulmonary function testing may be used as one diagnostic aid in the workup of the wheezing infant.

Expression of insulin-like growth factor-I and placental growth hormone mRNA in placentae: a comparison between normal and intrauterine growth retardation pregnancies

Intrauterine growth restriction (IUGR) is generally defined as the pathological restriction of fetal growth resulting in a fetus with birth weight below the 10th percentile for gestational age. Almost 75% of IUGR cases develop during third trimester. Studies on animals (rodents and sheep) as well as humans suggest that insulin-like growth factor-I (IGF-I), under the influence of placental growth hormone (PGH) plays crucial roles in fetal growth regulation during this period. Limited data are available with regard to IGF-I and PGH in placentae of normal and IUGR births. Therefore, in the present study, IGF-I and PGH mRNA expression has been studied in term placentae of normal (n = 10) and IUGR (n = 15) births by in-situ hybridization procedure. Their expression was also studied in first (n = 5) and second (n = 5) trimester placentae obtained from elective termination of normal pregnancies. Both IGF-I and PGH expression were found to be higher in the first and second trimester placentae compared to term placentae in normal pregnancies. However, IUGR term placentae showed increased expression of both IGF-I and PGH mRNA in comparison with normal placentae. Various mechanisms leading to the increased transcription of IGF-I and PGH mRNA in IUGR placenta are discussed. This increased transcription perhaps occurs in response to the reduction in the fetal growth.

Connexin43 deficiency causes delayed ossification, craniofacial abnormalities, and osteoblast dysfunction

Connexin(Cx)43 is the major gap junction protein present in osteoblasts. We have shown that overexpression of Cx45 in osteoblasts expressing endogenous Cx43 leads to decreased cell-cell communication (Koval, M., S.T. Geist, E.M. Westphale, A.E. Kemendy, R. Civitelli, E.C. Beyer, and T.H. Steinberg. 1995. J. Cell Biol. 130:987-995) and transcriptional downregulation of several osteoblastic differentiation markers (Lecanda, F., D.A. Towler, K. Ziambaras, S.-L. Cheng, M. Koval, T.H. Steinberg, and R. Civitelli. 1998. Mol. Biol. Cell 9:2249-2258). Here, using the Cx43-null mouse model, we determined whether genetic deficiency of Cx43 affects skeletal development in vivo. Both intramembranous and endochondral ossification of the cranial vault were delayed in the mutant embryos, and cranial bones originating from migratory neural crest cells were also hypoplastic, leaving an open foramen at birth. Cx43-deficient animals also exhibited retarded ossification of the clavicles, ribs, vertebrae, and limbs, demonstrating that skeletal abnormalities are not restricted to a neural crest defect. However, the axial and appendicular skeleton of Cx43-null animals were essentially normal at birth. Cell to cell diffusion of calcein was poor among Cx43-deficient osteoblasts, whose differentiated phenotypic profile and mineralization potential were greatly impaired, compared with wild-type cells. Therefore, in addition to the reported neural crest cell defect, lack of Cx43 also causes a generalized osteoblast dysfunction, leading to delayed mineralization and skull abnormalities. Cell to cell signaling, mediated by Cx43 gap junctions, was critical for normal osteogenesis, craniofacial development, and osteoblastic function.

Hypertension and stroke in Asia: prevalence, control and strategies in developing countries for prevention

Reliable statistics related to the prevalence, incidence and mortality of hypertension and stroke are not available from Asia. The data may be in national or institutional reports or journals published in the local language only. The mortality rate for stroke has been on the decline since the mid 1960s in the developed countries of Asia, such as Australia, New Zealand, and Japan, with some improvement in Singapore, Taiwan and Hong Kong, some areas of China and Malaysia about 15 years later. In India, China, Philippines, Thailand, Sri Lanka, Iran, Pakistan, Nepal, there has been a rapid increase in stroke mortality and prevalence of hypertension. The prevalence of hypertension according to new criteria (>140/90 mm Hg) varies between 15-35% in urban adult populations of Asia. In rural populations, the prevalence is two to three times lower than in urban subjects. Hypertension and stroke occur at a relatively younger age in Asians and the risk of hypertension increases at lower levels of body mass index of 23-25 kg/m2. Overweight, sedentary behaviour, alcohol, higher social class, salt intake, diabetes mellitus and smoking are risk factors for hypertension in most of the countries of Asia. In Australia, New Zealand and Japan, lower social class is a risk factor for hypertension and stroke. Population-based long-term follow-up studies are urgently needed to demonstrate the association of risk factors with hypertension in Asia. However prevention programmes should be started based on cross-sectional surveys and case studies without waiting for the cohort studies.

Alpha-gal-independent dual recognition and activation of xenogeneic endothelial cells and human naïve natural killer cells

BACKGROUND

Interaction between vascularized xenograft and host immune system is thought to occur via Galactose alpha (1,3) Galactose (Gala 1,3 gal) structures decorating the xenograft.

METHODS

We raised anti-Gala 1,3 gal-BSA polyclonal antibodies in baboons and investigated effect(s) of these antibodies as well as soluble Gala 1,3 gal-BSA on human naive natural killer (NK) cell interactions with porcine aortic endothelial cells.

RESULTS

We demonstrate that human naive (unstimulated) NK cells recognize xenogeneic endothelial cells under conditions where binding to the Gala 1,3 gal structures is minimized by the presence of blocking anti-Gala 1,3 gal IgG or soluble Gala 1-3 gal and in the absence of xenoreactive natural antibodies and complement. After xenogeneic encounter both endothelial cells and human NK cells are activated. Endothelial cell activation is rapid and is manifested initially by an intraendothelial calcium transient and subsequently by expression of P-selectin and vascular endothelial cell adhesion molecule-1 on the xenoendothelium surface. NK cell activation is manifested by increased expression of perforin and increased cytotoxicity towards the xenoendothelium. Neither recognition nor activation of the xenoendothelium was affected by the introduction of either anti-Gala 1,3 gal IgG or soluble Gala 1-3 gal.

CONCLUSION

Our data provide evidence that innate immune cells, such as NK cells, recognize and activate xenoendothelial cells independently of Gala 1-3 gal structures and raise the possibility of novel interactive sites on both human naive NK cells and discordant xenogeneic endothelium.

Fibromatoses of the extremities: clinicopathologic study of 36 cases

BACKGROUND AND OBJECTIVES

Fibromatoses of the extremities are rare and often recalcitrant to treatment. We evaluated the clinical and pathologic features of a group of extremity fibromatoses treated by surgical excision with or without adjuvant therapy to determine if any clinical or pathologic parameters were predictive of clinical outcome.

METHODS

Thirty-six extremity fibromatoses were evaluated. A number of clinical and histologic features were correlated with risk of local recurrence.

RESULTS

The cohort included 19 females and 17 males with ages ranging from 11-72 years (mean: 35 years), with 12 tumors of the upper and 24 tumors of the lower extremity. Tumors ranged in size from 1.5-15.5 cm (mean: 7.5 cm).Histologically, 26 were infiltrative, 3 had pushing borders and 7 had both. Mitotic counts ranged from 0-5/50 high-power fields (mean: 0.74). Surgical margins were positive in 22 cases. Seventeen patients were treated with postoperative adjuvant therapy including radiation therapy and tamoxifen. Follow-up information was available in 34 cases (from 1-202 months; mean: 83 months). Nineteen patients (56%) had recurrences, including 11 with multiple recurrences (range to first recurrence: 5-61 months; mean 23 months). Seventy-one percent of patients with a positive surgical margin and clinical follow-up had a local recurrence, compared to 31%with a negative surgical margin (P < 0.05). None of the other clinical or histologic parameters correlated with the risk for local recurrence.

CONCLUSIONS

Local control in fibromatoses of the extremities remains problematic. Aside from positive surgical margins, none of the other clinical or histologic parameters evaluated in this study were useful in predicting the risk of local recurrence.

A cross-cultural study of mental health beliefs and attitudes towards seeking professional help

BACKGROUND

This study sets out to examine the relationship between culture beliefs about the causes of mental distress and attitudes associated with seeking professional help for psychological problems. It was hypothesised that there is a meaningful and statistical relationship between these variables and that there will be a difference in this relationship between Asians and Westerners. Participants were 287 adults belonging to three groups (British Asian, western European and Pakistanis).

METHOD

Participants completed two questionnaires: the Orientations to Seeking Professional Help (Fischer and Turner 1970) and the Mental Distress Explanatory Model Questionnaire (Eisenbruch 1990) and a demographic data sheet.

RESULTS

Analysis indicated that positive attitudes toward seeking professional help for psychological distress were similar for British Asians, Westerners and Pakistanis. There were significant differences between the three groups in the causal attributions of mental distress. Although culture, as a variable, was not a significant predictor of a positive attitude to seeking professional help, causal beliefs of mental distress were significant predictors of attitudes to seeking help for the British Asian and the Pakistani groups. Beliefs were not significant predictors for attitudes to seeking help for the Western group.

CONCLUSION

It was concluded that culturally determined causal beliefs of mental distress contribute to attitudes towards seeking professional help for psychological problems for Asians. Implications for both research and the provision of more appropriate health services for the British Asian minority group in the United Kingdom are discussed.

Relative abundance of different cadherins defines differentiation of mesenchymal precursors into osteogenic, myogenic, or adipogenic pathways

Cadherins, a family of cell-cell adhesion molecules, provide recognition signals that are important for cell sorting and aggregation during tissue development. This study was performed to determine whether distinct cadherin repertoires define tissue-specific lineages during differentiation of immature C3H10T1/2 and C2C12 mesenchymal cells. Both cell lines expressed mRNA for N-cadherin (N-cad), cadherin-11 (C11), and R-cadherin (R-cad). After induction of osteogenesis by recombinant human BMP-2 (rhBMP-2) treatment, steady state N-cad mRNA slightly increased in C3H10T1/2 cells. Likewise, the abundance of C11 mRNA increased in both cell lines, although the changes were more remarkable in C2C12 cells. By contrast, R-cad expression was almost shut off by rhBMP-2. The immature but committed osteoblastic MC3T3-E1 cells exhibited only minor changes in N-cad and C11 mRNA abundance after rhBMP-2 treatment. Whereas adipogenic differentiation was associated with a net decrease of N-cad and C11 expression in C3H10T1/2 cells, induction of myogenesis in C2C12 cells resulted in up-regulation of N-cad, while R-cad mRNA became undetectable in either case. Similarly, the adipocytic 3T3-L1 cells expressed very low levels of all cadherins when fully differentiated. Therefore, the repertoire of cadherins present in undifferentiated mesenchymal cells undergoes distinct changes during transition to mature cell phenotypes. Although neither N-cad nor C11 represent strict tissue-specific markers, the relative abundance of these mesenchymal cadherins defines lineage-specific signatures, perhaps providing recognition signals for aggregation and differentiation of committed precursors.

Asymmetrical targeting of type II Na-P(i) cotransporters in renal and intestinal epithelial cell lines

Targeting of newly synthesized transporters to either the apical or basolateral domains of polarized cells is crucial for the function of epithelia, such as in the renal proximal tubule or in the small intestine. Recently, different sodium-phosphate cotransporters have been identified. Type II cotransporters can be subdivided into two groups: type IIa and type IIb. Type IIa is predominantly expressed in renal proximal tubules, whereas type IIb is located on the intestinal and lung epithelia. To gain some insights into the polarized targeting of the type II cotransporters, we have transiently expressed type IIa and type IIb cotransporters in several epithelial cell lines: two lines derived from renal proximal cells (opossum kidney and LLC-PK(1)), one from renal distal cells (Madin-Darby canine kidney), and one from colonic epithelium (CaCo-2). We studied the expression of the transporters fused to the enhanced green fluorescent protein. Our data indicate that the polarized targeting is dependent on molecular determinants most probably located at the COOH terminus of the cotransporters as well as on the cellular context.

Amelioration of the bleeding tendency of preoperative aspirin after aortocoronary bypass grafting

BACKGROUND

Aspirin therapy is widely used in the treatment of cardiac disease. It has been recognized as a causative factor for increased bleeding and blood loss after open heart operations.

METHODS

To determine whether high-dose aprotinin maintained its efficacy in reducing blood loss in the presence of aspirin pretreatment in patients undergoing aortocoronary bypass, we performed a double blind study on 60 adult patients. Half received high-dose aprotinin (Trasylol) and half placebo.

RESULTS

Total hemoglobin loss, the primary efficacy variable was reduced from 36.1 +/- 31.4 g (mean +/- SD) to 14.1 +/- 16.0 g (p = 0.002). Blood loss was reduced intraoperatively and total loss was reduced from 837.3 mL +/- 404.9 mL to 368.7 mL +/- 164.3 mL (p < 0.001). The number of patients who did not receive any donor blood products was significantly higher in the aprotinin-treated patients (56.7% versus 23.3%, p = 0.008). Activation of the clotting cascade was significantly less in the treated patients toward the end of cardiopulmonary bypass both by measurement of thrombin-antithrombin III complex (p < 0.0001) and prothrombin fragment 1 + 2 (p < 0.0001). D-Dimer generation was significantly less from the onset of bypass and after reversal of heparin in the aprotinin-treated patients (p < 0.0001).

CONCLUSIONS

High-dose aprotinin was highly effective in reducing bleeding in this high-risk group of patients. Biochemical analyses suggest the mechanism by which aspirin increases blood loss after cardiopulmonary bypass is different from the blood-preserving effects of aprotinin, which is acting as an antifibrinolytic agent.

Can peak expiratory flow predict airflow obstruction in children with asthma?

STUDY OBJECTIVES

A recent trend in the treatment of asthma has been the widespread, independent use of peak expiratory flow (PEF). We examined whether PEF monitoring creates inaccuracies in assessment of children with moderate to severe asthma.

METHODS

We compared the negative predictive value of PEF in relation to the forced expiratory volume in 1 second (FEV(1)), and to the forced expiratory flow between 25% and 75% of the vital capacity (FEF(25-75%)) at different levels of air trapping as determined by the residual volume over total lung capacity ratio (RV/TLC).

RESULTS

The study included 244 patients, ages 4 to 18 years with all classes of asthma severity, with FEV(1) ranging from 28% to 134% of predicted value. We analyzed 367 sets of pulmonary function tests performed throughout a 3-year period. Thirty percent of patients with a normal PEF value had an abnormal FEV(1) or FEF(25-75%). As air trapping increased, the ability of a normal PEF to predict normal FEV(1) and FEF(25-75%) readings fell from 83% to 53%. The negative predictive value was significantly lower for patients with RV/TLC ratio >30 compared with patients with RV/TLC <30.

CONCLUSIONS

The results of this study suggest that it might be possible to identify children for whom the PEF is likely to give false-negative results. As air trapping increases, it causes the PEF to give misleading reassurance of normal pulmonary function. Furthermore, poor predictiveness of PEF is obtained when values 80% of predicted for age are considered normal.

An adolescent case of sulfhemoglobinemia associated with high-dose metoclopramide and N-acetylcysteine

We describe the case of an adolescent girl who received high-dose metoclopramide in combination with oral N-acetylcysteine therapy for acute acetaminophen toxicity. Whole blood-sample analysis for abnormal hemoglobin pigments established the diagnosis of sulfhemoglobinemia. Metoclopramide has been shown to cause sulfhemoglobinemia, particularly when used in repeated high doses. Although N-acetylcysteine alone has not been associated as the cause, we suggest that sulfhemoglobine-mia is a potential complication in patients treated with metoclopramide for the nausea that often accompanies oral N-acetylcysteine therapy for acetaminophen toxicity. Cyanosis without respiratory distress should suggest this diagnosis.

An adolescent case of sulfhemoglobinemia associated with high-dose metoclopramide and N-Acetylcysteine

We describe the case of an adolescent girl who received high-dose metoclopramide in combination with oral N-acetylcysteine therapy for acute acetaminophen toxicity. Whole blood-sample analysis for abnormal hemoglobin pigments established the diagnosis of sulfhemoglobinemia. Metoclopramide has been shown to cause sulfhemoglobinemia, particularly when used in repeated high doses. Although N-acetylcysteine alone has not been associated as the cause, we suggest that sulfhemoglobinemia is a potential complication in patients treated with metoclopramide for the nausea that often accompanies oral N-acetylcysteine therapy for acetaminophen toxicity. Cyanosis without respiratory distress should suggest this diagnosis.

Comparison of the efficacy of inhaled fluticasone propionate, 880 microg/day, with flunisolide, 1500 microg/day, in moderate-to-severe persistent asthma

BACKGROUND

Inhaled corticosteroids have become the mainstay of asthma therapy. Few studies however, have compared inhaled steroids in children. We compared the efficacy of inhaled fluticasone propionate (FP), 880 microg/day (2 puffs of 220 microg/puff, BID) with inhaled flunisolide (FLU), 1500 microg/day (3 puffs of 250 microg/puff, BID).

METHODS

Thirty children with moderate to severe asthma, mean age 12.7 years (range 10 to 17 years), mean duration of asthma 8.4 years, initially received flunisolide 1500 microg/day for 1 year, and then were switched to fluticasone propionate 880 microg/day and followed for an additional year. Pulmonary function tests (PFTs) were monitored and analyzed before and after the switch for the duration of study. Mean percent predicted for age values for FVC, FEV1, FEF25-75%, and FEFR were compared at 1 month, 2 to 6-month intervals, and 7 to 12-month intervals and during the same season of the year. Pulmonary function tests within 3 weeks of an exacerbation were not included in the study. The number of asthma exacerbations, emergency room visits, hospital admissions, and number of school days lost were also compared.

RESULTS

There was significant improvement in mean asthma exacerbations/patient/year (1.7 +/- 1.66 SD) versus (4 +/- 2.6) (P < .0002); mean emergency room visits/patient/year (0.23 +/- 0.62) versus (1.2 +/- 1.74) (P = .004); mean hospital admissions for asthma/patient/year (0.2 +/- 0.61) versus (1.13 +/- 1.45) (P < .0002); and number of school days lost/patient/year (1.4 +/- 2.38) versus (7.93 +/- 6.7) (P < .0002) while patients were receiving fluticasone propionate as compared with flunisolide. Also, the mean percent values predicted for age in all time-periods (at 1 month, 2 to 6 months, and 7 to 12 months) revealed significant improvement in FEV1 and FEF25-75% (P < .05 for both parameters). As PFT can be affected by seasonal changes, PFT parameters were compared during the same season of the year and significant improvement in FVC and FEV1 was observed in all seasons while patients were receiving fluticasone propionate (FP) compared with flunisolide (FLU) (P < .05 for all parameters). Significant improvement in PEFR and FEF25-75% was observed only in spring and summer season.

CONCLUSION

Fluticasone propionate 880 microg/day improved lung function and quality of life in adolescents with moderate-to-severe asthma when compared with flunisolide 1500 microg/day.

Gastroesophageal reflux in infants with wheezing

The relation between silent gastroesophageal reflux (GER) and respiratory problems such as persistent wheezing in infants is not well-established. Between January 1994 and June 1997, we evaluated the incidence of GER in 84 otherwise healthy infants referred to the Pediatric Pulmonary Medicine Division at Kosair Children's Hospital for evaluation of daily wheezing, and we followed their clinical course for 18 months. All underwent 24-hr esophageal pH studies to evaluate GER. The pH probe study was performed at a mean age of 8.74 +/- 4.6 months. Infants with a positive GER study were treated with an H2 receptor antagonist (H2RA) and a prokinetic agent for a mean of 5.6 +/- 2.4 months. At first follow-up visit 3 weeks after esophageal pH studies infants treated with an H2RA and those who did not have GER but continued with daily wheezing were started on flunisolide nasal solution (0.025%) delivered by nebulizer (125 mcg t.i.d.). Infants in both groups were followed every 1-2 months for a mean of 18 months and if clinically improved, attempts to decrease their daily asthma medications were made. Fifty-four of 84 (64%) had positive esophageal pH studies (GER-positive group), and 24 of them (44%) had no gastrointestinal symptoms suggestive of GER. Thirty patients had normal esophageal pH studies (GER-negative group). Twenty-two of these 30 (73%) infants without GER required nebulized flunisolide, compared to 13 of 54 (24%) infants with GER (P < 0.0005). Thirty-five of 54 (64.8%) infants with GER were able to discontinue all daily asthma medications within 3 months of starting antireflux therapy, while none of the infants without GER were able to discontinue daily asthma medications during the follow-up period (P < 0.0005). We conclude that silent GER is common in infants with daily wheezing, and controlling GER improves morbidity and decreases the need for daily asthma medications.

Prevalence of gastroesophageal reflux in infants with recurrent brief apneic episodes

BACKGROUND

Apnea in an infant can be a diagnostic dilemma for the treating pediatrician. It is suggested that in some infants, gastroesophageal reflux (GER) might be a factor in the pathogenesis of apnea, although its role as a cause of apnea is still controversial.

OBJECTIVE

To evaluate the prevalence of GER in infants presenting with recurrent brief apneic periods.

PATIENTS AND METHODS

A retrospective review of the medical records of all the infants who underwent prolonged esophageal pH studies for brief apneic episodes (n=105) at the Kosair Children's Hospital in the six years from January 1992 to December 1997 was performed. Infants presenting with apparent life-threatening episodes were excluded.

RESULTS

Of 105 infants, 72 (68.6%) were younger than two months of age and 22 (21%) were born preterm. Fifty of 105 infants (47.6%) had positive esophageal pH studies for acid reflux. Among infants with positive pH studies, only 21 (42%) had associated gastrointestinal or feeding complaints.

CONCLUSION

GER is present in a large number of infants presenting with brief apneic episodes. Though the relationship between the two is still not fully established, GER may be a significant risk factor for such apneic episodes in infants.

Comparison of lung function in infants exposed to maternal smoking and in infants with a family history of asthma

STUDY OBJECTIVE

To compare lung function in infants exposed to maternal smoking with lung function in infants with a family history of asthma. There are no published studies comparing lung function in both groups.

DESIGN

Cross-sectional study.

SETTING

A tertiary pulmonary care center at a children's hospital.

PATIENTS

One hundred five infants with daily wheezing. Thirty-five infants had persistent exposure to maternal smoking, and 70 had a family history of asthma in parents or siblings.

MEASUREMENTS

Infant pulmonary function tests were compared between the two groups. The ratio of terminal to peak expiratory flow at tidal breathing at 25% of the previous expiration remaining and the ratio of terminal to peak expiratory flow with forced expiration at 25% of the previous expiration remaining (FEF25/PFEF) were used to evaluate peripheral airflow. A > 25% improvement in FEF25/PFEF after a bronchodilator challenge test was considered a positive response.

RESULTS

Most infants in both groups had evidence of peripheral airflow obstruction with forced expiration. In infants exposed to maternal smoking, only 4 of 35 (11.4%) responded to a bronchodilator, compared to 51 of 70 (72.9%) in the group with a family history of asthma (p < 0.0005). There was no statistically significant difference in total respiratory system compliance, total respiratory system resistance, tidal volume, and degree of peripheral airflow obstruction at tidal breathing or after forced expiration in both groups.

CONCLUSION

Infants with exposure to maternal smoking and infants with a family history of asthma have altered lung function, and a positive response to a bronchodilator is one variable that seems to differentiate the two groups.

Moderate hemoptysis of unknown etiology

The underlying cause and treatment of hemoptysis should be addressed promptly to avoid potentially life-threatening complications. We report on a previously healthy 11-year-old white boy who presented with acute hemoptysis. On bronchoscopy, bleeding was noted from the right upper and lower lobes. Right bronchial arteriography revealed multiple regions of abnormal "blushing" throughout the right bronchial arterial distribution which was successfully controlled by right bronchial arterial embolization. In spite of an extensive work-up, we were not able to determine the cause of bleeding. The patient has been followed for 18 months without any recurrence and without evidence of any systemic disease. Our patient does not fit any diagnostic category of pulmonary bleeding and further case reports are needed to delineate this entity.

Lung function in infants with wheezing and gastroesophageal reflux

Eighty-four otherwise healthy infants with daily wheezing underwent infant pulmonary function tests (IPFTs) and 24-h esophageal pH probe studies. Fifty-four (64%) infants had positive pH probe studies, and 30 infants had negative pH probe studies. Many infants in both groups had evidence of peripheral airflow obstruction at tidal breathing and on forced expiration as measured by thoracoabdominal compression. In infants with gastroesophageal reflux (GER), only 9 of 54 (16.6%) responded to bronchodilator therapy compared to 20 of 30 (66.6%) in the group with negative pH probe studies (P < 0.0005). In infants with positive pH studies, family history of asthma (n = 16) correlated well with positive response to bronchodilators (P < 0.0005), and all infants exposed to maternal smoking (n = 11) had no response to bronchodilators. Forty-four percent of infants with a positive pH probe had no gastrointestinal symptoms suggestive of GER. In infants with a negative pH probe, family history of asthma (n = 24) correlated well with positive response to bronchodilators (P < 0.0005), and exposure to maternal smoking (n = 8) correlated well with no response to bronchodilator therapy (P < 0.0005). We conclude that silent GER is common in infants with persistent wheezing. Furthermore, infants with GER are less likely to respond to bronchodilator therapy, and exposure to maternal smoking and family history of asthma may be significant independent factors.

Defective corticogenesis and reduction in Reelin immunoreactivity in cortex and hippocampus of prenatally infected neonatal mice

Recent reports indicate an association between second trimester human influenza viral infection and later development of schizophrenia. Postmortem human brain studies also provide evidence for reduction in Reelin mRNA (an important secretory protein responsible for normal lamination of the brain) in schizophrenic brains. We hypothesized that human influenza infection in day 9 pregnant mice would alter the expression of reelin in day 0 neonatal brains. Prenatally-infected murine brains from postnatal day 0 showed significant reductions in reelin-positive cell counts in layer I of neocortex and other cortical and hippocampal layers when compared to controls. Whereas layer I Cajal-Retzius cells produced significantly less Reelin in infected animals, the same cells showed normal production of calretinin and nNOS when compared to control brains. Moreover, prenatal viral infection caused decreases in neocortical and hippocampal thickness. These results implicate a potential role of prenatal viral infection in causation of neuronal migration abnormalities via reduction in Reelin production in neonatal brains.

Complement activation during major surgery: the effect of extracorporeal circuits and high-dose aprotinin

OBJECTIVE

To assess the in vivo contribution to complement activation of an extracorporeal circuit and the use of high-dose aprotinin during major surgery.

DESIGN

Sequential samples were obtained from 8 patients undergoing thoracic surgery, 20 patients undergoing orthotopic liver transplantation (OLT) using venovenous bypass, and 19 patients undergoing cardiac surgery using cardiopulmonary bypass (CPB).

INTERVENTION

The latter two groups were part of a randomized controlled trial of high-dose aprotinin.

MEASUREMENTS

Total complement activation was measured with the hemolytic complement activity and the C3 activation-specific marker, C3d antigen.

MAIN RESULTS

Complement activation did not occur during thoracic surgery. During OLT, C3d antigen levels, expressed as mean +/- standard deviation (SD), were elevated from baseline at skin closure (8.6 +/- 2.5 v 13.0 +/- 5.2 mg/L; p = 0.0082). During cardiac surgery, C3d antigen levels increased 10 minutes after the start of CPB (pre-CPB, 8.0 +/- 1.9 v 14.2 +/- 3.1 mg/L; p = 0.0001) and remained at greater than baseline values postoperatively (8.0 +/- 1.9 v 11.8 +/- 2.3 mg/L; p = 0.002). There was no difference in complement activation in those receiving high-dose aprotinin during OLT or cardiac surgery. Complement activation during cardiac surgery using extracorporeal circulation occurred to a greater extent than during OLT and thoracic surgery. Complement activation during cardiac surgery or OLT was not attenuated by the use of high-dose aprotinin.

Identification and characterization of the Nudix hydrolase from the Archaeon, Methanococcus jannaschii, as a highly specific ADP-ribose pyrophosphatase

The MJ1149 gene from the Archaeon, Methanococcus jannaschii, has been cloned and expressed in Escherichia coli. The 19-kDa protein containing the Nudix box, GX5EX7REUXEEXGU, has been purified and identified as a highly specific enzyme catalyzing the Mg2+-dependent hydrolysis of ADP-ribose according to the equation: ADP-ribose + H2O --> AMP + ribose-5-phosphate. The enzyme retains full activity when heated to 80 degreesC, and the rate of hydrolysis is 15-fold higher at 75 degreesC than at 37 degreesC in keeping with the thermophilicity of the organism. This is the first Nudix hydrolase identified from the Archaea, indicating that the family of enzymes containing the Nudix signature sequence is represented in all three kingdoms.

Activation of coagulation and fibrinolysis during cardiothoracic operations

BACKGROUND

During open cardiac operations using cardiopulmonary bypass, there is activation of coagulation and fibrinolysis. We assessed the separate contributions of the surgical procedure itself and cardiopulmonary bypass to this, by studying sequential samples from patients undergoing routine open cardiac operations or thoracic operations without cardiopulmonary bypass.

METHODS

Activation of coagulation and the extent of fibrinolysis were measured from sequential samples obtained before the operation to 48 hours after the operation for 7 thoracic patients and 8 cardiac patients.

RESULTS

In the thoracic group operation length was shorter (p = 0.002), and there was no significant increase in thrombin-antithrombin III complexes or D-dimers until 24 hours postoperatively. In contrast, there was a highly significant increase in thrombin-antithrombin III complexes (p = 0.0043) and D-dimer levels (p = 0.009) during cardiopulmonary bypass. The increase in fibrinolytic activity was caused by an increase in tissue plasminogen activator (p = 0.013). At 48 hours postoperatively, the cardiac patients had a more hypercoagulable state than thoracic patients with significantly higher levels of thrombin-antithrombin III complexes (p = 0.041) and plasminogen activator inhibitor-1 activity (p = 0.0033).

CONCLUSIONS

This study suggests the major activation of coagulation and fibrinolysis seen during cardiac operations is caused by the use of cardiopulmonary bypass.

Improved morbidity with the use of nasal continuous positive airway pressure in I-cell disease

Patients with I-cell disease (mucolipidosis II) present with progressive morbidity failure to thrive, cardiomegaly, and recurrent respiratory tract infections leading to progressive deterioration and early death. We evaluated use of nasal continuous positive airway pressure (NCPAP) for 6 months in a 2-year-old girl with I-cell disease, obstructive sleep apnea (OSA), and craniofacial anomalies. We observed a marked decrease in hospitalizations for respiratory problems and a marked improvement in arterial blood gases with the use of NCPAP. In patients with I-cell disease, anatomical defects with superimposed upper respiratory tract infections cause worsening of OSA, and OSA contributes significantly to morbidity. In such patients NCPAP can lessen morbidity and can improve the quality of life.

Treatment of neutrophils with cytochalasins converts rolling to stationary adhesion on P-selectin

We investigated how disruption of the actin cytoskeleton with cytochalasins modified adhesion of neutrophils rolling on a platelet monolayer in vitro at 37 degrees C. When perfused at a wall shear stress of 0.1 Pa over rolling cells, cytochalasin B, cytochalasin D and dihydro-cytochalasin B each induced dose-dependent (approximately 1-10 microg/ml) conversion to stationary attachment over minutes. Stopping was associated with cell elongation to a teardrop shape. Increased deformability of cytochalasin-treated cells was independently evidenced by more rapid entry into a micropipette. Spherical shape and rolling were reestablished concurrently on washout of the cytochalasins, while increasing the shear stress in the range 0.2 to 1.0 Pa induced tear-drop-shaped cells to restart rolling even in the continued presence of cytochalasin. When cells were pretreated with cytochalasin B, they attached efficiently at 0.1 Pa, rolled initially and only stopped after approximately 30 seconds when elongation had been established. Adhesion was selectin-mediated in the presence or absence of cytochalasin B, as judged by inhibition of attachment by antibody against P-selectin and failure of antibody against beta2-integrin CD18 to influence adhesion. Cessation of rolling is unlikely to have arisen from an increase in adhesive contact area induced by deformation because stopped cells were found to be attached only at their pointed end. Failure of adhesive bonds to peel may have arisen because selectin ligands freed of cytoskeletal restraint were dragged into this tethered region and clustered there, and because force applied to bonds was influenced by the change in cell shape. These results suggest that cytoskeletal structure is an important modulator of dynamic adhesive responses of leukocytes, via effects on adhesion receptors and cellular mechanics.

Bronchiectasis in pediatric AIDS

OBJECTIVES

There are several reports of the pulmonary findings in children with HIV disease; however, the occurrence of bronchiectasis rarely has been noted. We evaluated occurrence of bronchiectasis in a large group of children referred to us with AIDS pneumopathy.

METHODS

From January 1984 to April 1996, 203 children with AIDS and respiratory problems were referred to the pediatric pulmonary division at Children's Medical Center of Brooklyn. Medical records for 164 of these children were available and retrospectively reviewed.

RESULTS

Uncomplicated pneumonia was present in 75, 24 had recurrent pneumonia, and 18 had unresolved pneumonia; lymphocytic interstitial pneumonitis (LIP) was diagnosed in 47 patients, worsening with time in all patients. Bronchiectasis was observed in 26 patients (26/164, 15.8%), diagnosed by chest radiograph in 26 (26/26, 100%), confirmed by CT scan of chest in 10 (10/26, 38.4%), and by histology in three (3/26, 11.5%). Median age at time of diagnosis of bronchiectasis was 7.5 years (range, 1 to 16 years). Sixteen children with LIP developed bronchiectasis (16/47, 34.0%). Three patients with recurrent pneumonia (3/24, 12.5%) developed bronchiectasis. Five patients with unresolved pneumonia (5/18, 27.7%) developed bronchiectasis. One infant developed bronchiectasis after Pneumocystis carinii pneumonia; another child developed bronchiectasis after P. carinii and Mycobacterium tuberculosis pneumonia. The CD4+ T-cell counts measured within 6 months of diagnosis of bronchiectasis were available in 23/26 patients and, all were < 100 cells per cubic millimeter.

CONCLUSION

We conclude, from our experience, that there is a significant occurrence of bronchiectasis in children with AIDS and pulmonary disease, especially in children developing LIP, recurrent pneumonia and unresolved pneumonia, and CD4+ T-cell counts < 100 cells per cubic millimeter.

Actin polymerisation regulates integrin-mediated adhesion as well as rigidity of neutrophils

Activation of adherent neutrophils causes them to convert from selectin-mediated rolling to integrin-mediated immobilisation and migration. Migration is known to depend on formation and redistribution of filamentous (F) actin, but although immobilisation in seconds parallels early cortical actin polymerisation, no link has been proven. We tested the effect of the actin-polymerising agent jasplakinolide (10 microM) on adhesive and mechanical properties of neutrophils. Pretreated cells were able to adhere and roll on immobilised platelets in a flow-based adhesion assay, but whereas untreated rolling cells became immobilised in seconds when chemotactic formyl peptide (fMLP, 0.1 microM) was superfused over them, the cells treated with jasplakinolide continued rolling. Pretreatment with jasplakinolide also blocked de novo expression of integrin CD11b and shape change which otherwise occurred in minutes after treatment with fMLP. Jasplakinolide directly caused actin polymerisation within neutrophils, evidenced by a marked increase in rigidity (resistance to aspiration into a 5 microm micropipette) and increase in association of actin with the Triton-insoluble cytoskeleton. These results indicate that rearrangement of the actin cytoskeleton regulates integrin-mediated adhesion of activated neutrophils, as well as their migration and mechanical properties.

The potential roles of the conserved amino acids in human liver mitochondrial aldehyde dehydrogenase

The sequence alignment of all known aldehyde dehydrogenases showed that only 23 residues were completely conserved (Hempel, J., Nicholas, H., and Lindahl, R. (1993) Protein Sci. 2, 1890-1900). Of these 14 were glycines and prolines. Site-directed mutagenesis showed that Cys302 was the essential nucleophile and that Glu268 was the general base necessary to activate Cys302 for both the dehydrogenase and esterase reaction. Here we report the mutational analysis of other conserved residues possessing reactive side chains Arg84, Lys192, Thr384, Glu399, and Ser471, along with partially conserved Glu398 and Lys489, to determine their involvement in the catalytic process and correlate these finding with the known structure of mitochondrial ALDH (Steinmetz, C. G., Xie, P.-G., Weiner, H., and Hurley, T. D. (1997) Structure 5, 701-711). No residue was found to be absolutely essential, but all the mutations caused a decrease in the specific activity of the enzyme. None of the mutations affected the Km for aldehyde significantly, although k3, the rate constant calculated for aldehyde binding was decreased. The Km and dissociation constant (Kia) for NAD+ increased significantly for K192Q and S471A compared with the native enzyme. Mutations of only Lys192 and Glu399, both NAD+-ribose binding residues, led to a change in the rate-limiting step such that hydride transfer became rate-limiting, not deacylation. Esterase activity of all mutants decreased even though mutations affected different catalytic steps in the dehydrogenase reaction.

Involvement of glutamate 399 and lysine 192 in the mechanism of human liver mitochondrial aldehyde dehydrogenase

Mutation to the conserved Glu399 or Lys192 caused the rate-limiting step of human liver mitochondrial aldehyde dehydrogenase (ALDH2) to change from deacylation to hydride transfer (Sheikh, S., Ni, L., Hurley, T. D., and Weiner, H. (1997) J. Biol. Chem. 272, 18817-18822). Here we further investigated the role of these two NAD+-ribose-binding residues. The E399Q/K/H/D and K192Q mutants had lower dehydrogenase activity when compared with the native enzyme. No pre-steady state burst of NADH formation was found with the E399Q/K and K192Q enzymes when propionaldehyde was used as the substrate; furthermore, each mutant oxidized chloroacetaldehyde slower than propionaldehyde, and a primary isotope effect was observed for each mutant when [2H]acetaldehyde was used as a substrate. However, no isotope effect was observed for each mutant when alpha-[2H]benzaldehyde was the substrate. A pre-steady state burst of NADH formation was observed for the E399Q/K and K192Q mutants with benzaldehyde, and p-nitrobenzaldehyde was oxidized faster than benzaldehyde. Hence, when aromatic aldehydes were used as substrates, the rate-limiting step remained deacylation for all these mutants. The rate-limiting step remained deacylation for the E399H/D mutants when either aliphatic or aromatic aldehydes were used as substrates. The K192Q mutant displayed a change in substrate specificity, with aromatic aldehydes becoming better substrates than aliphatic aldehydes.

Allosteric inhibition of human liver aldehyde dehydrogenase by the isoflavone prunetin

Isoflavonoid derivatives including prunetin (4',5-dihydroxy-7-methoxyisoflavone) were shown to be potent inhibitors of human aldehyde dehydrogenases (Keung W-M and Vallee BL, Proc Natl Acad Sci USA 90: 1247-1251, 1993). The inhibition reaction was reinvestigated using recombinantly expressed human aldehyde dehydrogenases. The kinetic analyses showed that prunetin inhibits competitively against both NAD and propionaldehyde with the mitochondrial and cytoplasmic enzymes. The Ki value for the mitochondrial enzyme was much lower than for the cytoplasmicenzyme. A mixed pattern of inhibition was obtaiend with the mitochondrial enzyme in the presence of Mg2+. Only one mole of prunetin binds per mole of tetrameric mitochondrial enzyme, which remains unaltered in the presence of Mg2+. Prunetin did not displace NADH from the enzyme-NADH complex. Propionaldehyde did not reverse the loss of fluorescence obtained due to enzyme-prunetin complex formation, indicating that prunetin may not be interacting at the substrate site. The esterase activity of the mitochondrial enzyme was also inhibited by prunetin in a competitive manner. The replacement of lysine 192 by glutamine resulted in a mutant with a 20% kcat and a 100-fold increase in the Km for NAI) compared with the native enzyme. However, the Ki value of prunetin against NAD was similar to that observed with the native enzyme. Prunetin, even at a very high concentration, was not an inhibitor of alcohol and malate dehydrogenase. It was concluded that prunetin may act as an allosteric inhibitor of aldehyde dehydrogenase.

Cytokine pattern in relation to disease progression in human immunodeficiency virus-infected children

Cytokine mRNA expression and stimulus-induced cytokines were examined in peripheral blood mononuclear cells in 62 human immunodeficiency virus (HIV)-infected children and uninfected controls. Compared with that in controls, constitutive mRNA expression in patients was increased for tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, and interleukin (IL)-10 and decreased for IL-12; it was undetectable for IL-2 and IL-4 in both patients and controls. Stimulus-induced secretion of TNF-alpha, IFN-gamma, IL-12, and IL-4 was less than that in controls; IL-10 secretion was similar. There was no increase in stimulus-induced or constitutive IL-4 or IL-10 in children with severe immunologic deficit compared with controls. A higher stimulus-induced IL-10 secretion and a lower constitutive TNF-alpha mRNA were associated with a slower rate of disease progression, and TNF-alpha mRNA expression correlated with lower plasma HIV RNA. Thus, constitutive cytokine mRNA expression differs from stimulus-induced cytokine responses. The dominant defect in HIV-infected children appears to be one of reduced type 1 cytokines, predominantly IL-2.

Heterotetramers of human liver mitochondrial (class 2) aldehyde dehydrogenase expressed in Escherichia coli. A model to study the heterotetramers expected to be found in Oriental people

About 50% of the Oriental population have less liver mitochondrial aldehyde dehydrogenase (ALDH2) activity than do other people. It was found that they possessed an enzyme with a lysine at position 487 (E487K) instead of glutamate (Glu487). We previously found that the Km for NAD of recombinant human and rat E487K enzymes increased more than 150-fold (Farrés, J., Wang X., Takahashi, K., Cunningham, S. J. , Wang, T.T., and Weiner, H (1994) J. Biol. Chem. 269, 13854-13860). Many aldehyde dehydrogenase-deficient people were found to be heterozygous when genotyped for ALDH2. In this study liver tissue from heterozygous people was analyzed and found to possess mRNAs for both the glutamate and the lysine subunits. Western blot analysis showed that the glutamate subunit was present. The cDNAs for Glu487 and E487K were coexpressed on one plasmid in Escherichia coli, and the enzyme forms were separated from each other by isoelectric focusing to show that heterotetramers were formed. Only one Km value for NAD could be measured with the purified heterotetrameric enzyme that possessed just 16-18% activity of the glutamate homotetrameric enzyme. The E487K homotetramers had 8% specific activity of the Glu487 enzyme. There was no pre-steady state burst of NADH formation with the heterotetramer, a property found with the glutamate enzyme. Similar results were found for the coexpressed rat liver enzyme, except that a higher specific activity, 48%, was obtained. Thus, we conclude that presence of the lysine subunit altered the activity of the glutamate subunit in the heterotetramer to make it function more like an E487K enzyme.

Foreign body in the hypopharynx--an unusual presentation

A case is described of a foreign body (a metallic paper clip) in the hypopharynx of an 18 month old child presenting with recurrent respiratory tract infections. The child was treated with antibiotics at two accident and emergency departments without any benefit. A high degree of suspicion is necessary in young children, as a history of ingestion of a foreign body may not be forthcoming. It is important to be aware of the possibility of a foreign body in young children, particularly when the clinical presentation is atypical.

Continuous activation and deactivation of integrin CD11b/CD18 during de novo expression enables rolling neutrophils to immobilize on platelets

In an in vitro flow model, unstimulated neutrophils rolled steadily over a surface coated with platelets, until superfusion of the chemotactic peptide formyl-methionyl-leucyl-phenylalanine (fMLP) caused a dose-dependent (10(-11) to 10(-7) mol/L) transition from rolling to stationary attachment in seconds, followed more slowly by neutrophil shape change and spreading on the surface, However, at low concentrations of Ca2+ and Mg2+ (0.1 mmol/L and 0.05 mmol/L, respectively, rather than physiologic 1 mmol/L and 0.5 mmol/L), neutrophils first halted but then started to roll again and to detach from the surface over 5 to 10 minutes. At the low cation concentration, stopping was largely inhibited by antibodies to the neutrophil integrins CD18 or CD11b, but not CD11a. When neutrophils were pretreated with antibodies to CD11b or CD18 in 1 mmol/L Ca2+ 0.5 mmol/L Mg2+, stopping was not prevented but delayed. However, if antibodies were also included with the superfused fMLP, stopping was inhibited, and detachment followed. This indicates that CD11b/CD18 was newly expressed during shape change and mediated the second phase of neutrophil immobilization and spreading in a cation-dependent manner. Prestimulated neutrophils also bound to platelets and spread, but immobilization was blocked if they were perfused with antibody to CD18 or CD11b or with low Ca2+ and Mg2+. Examining the cation-dependence further, it was evident that the presence of Mg2+ was essential for integrin-mediated adhesion and that the Mg2+ concentration determined whether immobilization could be maintained or was transient. Continuous superfusion of fMLP was also essential for maintenance of stable adhesion and spreading. Thus, activation of constitutive CD11b/CD18 rapidly and reversibly converted rolling to stationary attachment, whereas maintenance of adhesion and neutrophil spreading required continual expression of additional CD11b/CD18 that was only functional at physiologic Mg2+. Continual activation and deactivation of CD11b/CD18 during de novo expression could mediate immobilization and onward migration of neutrophils in vivo, and activated platelets appear capable of supporting this process as well as endothelial cells.