Circulating tumour cells to drive the use of neoadjuvant chemotherapy in patients with muscle-invasive bladder cancer.

BACKGROUND: Guidelines recommend neoadjuvant chemotherapy (NAC) for the treatment of nonmetastatic muscle-invasive bladder cancer (MIBC). NAC is, however, underutilized in practice because of its associated limited overall survival (OS) benefit and significant treatment-related toxicity. We hypothesized that the absence of circulating tumour cells (CTCs) identifies MIBC patients with such a favourable prognosis that NAC may be withheld. PATIENTS AND METHODS: The CirGuidance study was an open-label, multicentre trial that included patients with clinical stage T2-T4aN0-N1M0 MIBC, scheduled for radical cystectomy. CTC-negative patients (no CTCs detectable using the CELLSEARCH system) underwent radical surgery without NAC; CTC-positive patients (≥1 detectable CTCs) were advised to receive NAC, followed by radical surgery. The primary endpoint was the 2-year OS in the CTC-negative group with a prespecified criterion for trial success of ≥75% (95% confidence interval (CI) ±5%). RESULTS: A total of 273 patients were enrolled. Median age was 69 years; median follow-up was 36 months. The primary endpoint of 2-year OS in the CTC-negative group was 69.5% (N = 203; 95% CI 62.6%-75.5%). Two-year OS was 58.2% in the CTC-positive group (N = 70; 95% CI 45.5%-68.9%). CTC-positive patients had a higher rate of cancer-related mortality [hazard ratio (HR) 1.61, 95% CI 1.05-2.45, P = 0.03] and disease relapse (HR 1.87, 95% CI 1.28-2.73, P = 0.001) than CTC-negative patients. Explorative analyses suggested that CTC-positive patients who had received NAC (n = 22) survived longer than CTC-positive patients who had not (n = 48). CONCLUSION: The absence of CTCs in MIBC patients was associated with improved cancer-related mortality and a lower risk of disease relapse after cystectomy; however, their absence alone does not justify to withhold NAC. Exploratory analyses suggested that CTC-positive MIBC patients might derive more benefit from NAC. TRIAL REGISTRATION: Netherlands Trial Register NL3954; https://www.trialregister.nl/trial/3954.

Motor timing learned without motor training.

Improvements due to perceptual training are often specific to the trained task and do not generalize to similar perceptual tasks. Surprisingly, given this history of highly constrained, context-specific perceptual learning, we found that training on a perceptual task showed significant transfer to a motor task. This result provides evidence for a common neural architecture underlying analysis of sensory input and control of motor output, and suggests a potential role for perception in motor development and rehabilitation.

Chemosensitive serotonergic neurons are closely associated with large medullary arteries.

We have previously shown that serotonergic neurons of the medulla are strongly stimulated by an increase in CO(2), suggesting that they are central respiratory chemoreceptors. Here we used confocal imaging and electron microscopy to show that neurons immunoreactive for tryptophan hydroxylase (TpOH) are tightly apposed to large arteries in the rat medulla. We used patch-clamp recordings from brain slices to confirm that neurons with this anatomical specialization are chemosensitive. Serotonergic neurons are ideally situated for sensing arterial blood CO(2), and may help maintain pH homeostasis via wide-ranging effects on brain function. The results reported here support a recent proposal that sudden infant death syndrome (SIDS) results from a developmental abnormality of medullary serotonergic neurons.

Exercise training increases skeletal muscle mitochondrial volume density by enlargement of existing mitochondria and not de novo biogenesis.

AIMS: (i) To determine whether exercise-induced increases in muscle mitochondrial volume density (MitoVD ) are related to enlargement of existing mitochondria or de novo biogenesis and (ii) to establish whether measures of mitochondrial-specific enzymatic activities are valid biomarkers for exercise-induced increases in MitoVD . METHOD: Skeletal muscle samples were collected from 21 healthy males prior to and following 6 weeks of endurance training. Transmission electron microscopy was used for the estimation of mitochondrial densities and profiles. Biochemical assays, western blotting and high-resolution respirometry were applied to detect changes in specific mitochondrial functions. RESULT: MitoVD increased with 55 ± 9% (P < 0.001), whereas the number of mitochondrial profiles per area of skeletal muscle remained unchanged following training. Citrate synthase activity (CS) increased (44 ± 12%, P < 0.001); however, there were no functional changes in oxidative phosphorylation capacity (OXPHOS, CI+IIP ) or cytochrome c oxidase (COX) activity. Correlations were found between MitoVD and CS (P = 0.01; r = 0.58), OXPHOS, CI+CIIP (P = 0.01; R = 0.58) and COX (P = 0.02; R = 0.52) before training; after training, a correlation was found between MitoVD and CS activity only (P = 0.04; R = 0.49). Intrinsic respiratory capacities decreased (P < 0.05) with training when respiration was normalized to MitoVD. This was not the case when normalized to CS activity although the percentage change was comparable. CONCLUSIONS: MitoVD was increased by inducing mitochondrial enlargement rather than de novo biogenesis. CS activity may be appropriate to track training-induced changes in MitoVD.

Milestones and controversies in maternal and child health: examining a brief history of micronutrient fortification in the US.

Fortification of our food and drinking supply has decreased morbidity rates related to micronutrient deficiencies among mothers and their children, particularly during the perinatal and neonatal periods of development. The purpose of this historical review is to examine the impact of public policy changes related to micronutrient fortification. We provide a historical investigation of achievements and controversies related to iodine, vitamin D, fluoride and folic acid fortifications in our food and drinking supply. We also discuss the current status of fortification recommendations and their significance to maternal and child health.

Effect of adrenocorticotropin administration on the biosynthesis of corticosteroid-binding globulin in fetal sheep.

Parturition in sheep is initiated by the fetus through activation of the fetal hypothalamic-pituitary-adrenal axis and is associated with increased concentrations of ACTH, cortisol, and corticosteroid-binding globulin (CBG) in the fetal circulation during the final 10-15 days of pregnancy. Premature parturition and a precocious elevation in fetal plasma CBG are produced by intrafetal ACTH administration, but the possible sources of CBG in the ovine fetus are not known. To determine these sites, CBG mRNA was measured in tissues from fetal sheep in late pregnancy and after intrafetal ACTH treatment, using a sheep CBG cDNA. Fetal ACTH treatment caused a significant increase in the fetal plasma corticosteroid-binding capacity (CBC), although there was no significant difference in CBC between umbilical arterial and umbilical venous plasma. After ACTH treatment, CBC was elevated in fetal liver and kidney. Cortisol binding in these tissues had characteristics similar to those of cortisol binding in fetal sheep plasma. By Northern blot analysis a single mRNA (1.7 kilobases) for CBG was detected in fetal liver, kidney, lung, and adrenal, but not in placenta. The abundance of CBG mRNA in the fetal liver was greater than that in other tissues, but was unchanged by ACTH treatment. The level of CBG mRNA in the fetal kidney, but not in other tissues, increased 3-fold after ACTH. We conclude that the elevation in plasma CBC after intrafetal ACTH, and presumably also at term pregnancy, does not reflect production of CBC by the placenta or transfer from the mother. Rather, it results from production primarily in the fetal liver and kidney, although only in the latter tissue is CBG mRNA accumulation increased by intrafetal ACTH treatment.

Chronic administration of low doses of adrenocorticotropin to hypophysectomized fetal sheep leads to normal term labor.

Parturition in the sheep is preceded by an increase in the plasma concentration of fetal ACTH and an increase in the plasma cortisol concentration. The role and importance of the increase in fetal ACTH in stimulating fetal glucocorticoid synthesis and the subsequent onset of labor require closer examination, as it has been demonstrated that the fetal adrenal becomes more responsive to ACTH in late gestation. This study sets out to determine whether the increase in plasma ACTH in the late gestation fetal sheep is essential for maturation of the fetal adrenal gland and normal delivery. Fetal sheep were either hypophysectomized (HX) and cannulated or cannulated only (intact) at 125 days gestation. Immediately after surgery, HX fetuses were infused with a constant dose of ACTH-(1-24) (ACTH/HX; 100 ng/h.kg, i.v.) or saline (SAL/HX) until uterine electromyography indicated the onset of labor or 161 days gestation was reached (term = 147 +/- 2.6 days). The mean gestational age at labor of the ACTH/HX group was 147 +/- 2.9 days, whereas none of the animals in the SAL/HX entered labor, and they were killed at 161 days gestation. The concentration of ACTH in both ACTH/HX and SAL/HX fetal plasma was less than 2.2 pg/ml throughout the study. The concentration of cortisol in ACTH/HX fetuses mimicked that in intact fetuses in late gestation, reaching 80 ng/ml at term. The concentration of cortisol in SAL/HX fetuses remained less than 5 ng/ml. This study supports the hypothesis that the ovine fetal adrenal becomes increasingly responsive to ACTH in late gestation and indicates that ACTH may only be permissive in the activation of adrenal function. In intact fetal sheep there may be endogenous inhibition of the fetal adrenal, requiring relatively high plasma concentrations of ACTH [100-250 pg/ml ACTH-(1-39)] in late gestation.

Development of adrenocorticotropin-(1-39) and precursor peptide secretory responses in the fetal sheep during the last third of gestation.

Although it is known that concentrations of immunoreactive ACTH increase during late gestation in fetal sheep plasma, the nature of the ACTH has not been well characterized. We used two-site immunoradiometric assays to separately measure high mol wt ACTH precursors (POMC and pro-ACTH) and ACTH-(1-39) in plasma of fetal sheep with chronic arterial and venous catheters. We compared the ratio of these peptides as a function of gestational age under basal conditions and in response to exogenous vasopressin and/or corticotropin-releasing hormone. Under basal conditions, the concentration of precursors was not changed throughout the last third of gestation; however, ACTH-(1-39) increased significantly approaching term. The molar ratio of precursors to ACTH-(1-39), therefore, decreased from 15.8 +/- 1.0 at 110 days to 7.9 +/- 0.6 at 140 days gestation. At all gestational ages, vasopressin and corticotropin-releasing hormone increased ACTH-(1-39) and precursors, albeit with different time courses. At 120 days gestation, arginine vasopressin plus CRH produced synergistic increases in ACTH-(1-39) and precursors, whereas the response was only additive at other ages. The present results indicate that the elevation in the resting plasma immunoreactive ACTH concentration that occurs near term is constituted by an increase in the concentration of ACTH-(1-39) relative to those of POMC and pro-ACTH, which may have further physiological significance. Also, CRH and AVP are potent stimulators of both ACTH-(1-39) and ACTH precursors.

Glucocorticoid-induced increase in plasma corticosteroid-binding globulin levels in fetal sheep is associated with increased biosynthesis and alterations in glycosylation.

In fetal sheep, there is a concomitant prepartum rise in cortisol and corticosteroid-binding globulin (CBG) that maintains a low free plasma cortisol level and allows for a low negative feedback effect of cortisol on the secretion of ACTH from the fetal pituitary. However, the stimulus for the prepartum increase in CBG and the mechanism(s) of this effect are not known. It has been proposed that glucocorticoids increase CBG concentrations, and therefore, we infused fetal sheep with the synthetic glucocorticoid dexamethasone (DEX; 2 micrograms/min over 15 min every 2 h for 96 h, n = 5) or saline (n = 5). The plasma corticosteroid-binding capacity increased from 30.0 +/- 2.4 to 55.6 +/- 7.7 and 92.6 +/- 11.1 ng/ml at 48 and 96 h, respectively, of DEX infusion. To examine possible mechanisms of increasing fetal plasma CBG, we first cloned and sequenced a sheep CBG cDNA and purified the protein. This allowed us to deduce the primary structure of ovine CBG and to demonstrate that hepatic CBG mRNA abundance (single transcript of 1.8 kilobases) rose from 0.9 +/- 0.2 to 3.6 +/- 1.6 arbitrary units after 96 h of DEX treatment. Fetal DEX treatment produced a significant increase (7.1 +/- 1.2% to 13.1 +/- 1.4%) in the Concanavalin-A-binding forms of CBG that predominate in adult sheep plasma. There was negligible transfer of purified [125I]CBG from the ewe to fetal plasma, urine, or amniotic fluid. We also injected adult sheep with DEX (10 mg/day for 4 days) and demonstrated a significant decrease in plasma corticosteroid-binding capacity by 24 h, which remained suppressed for the duration of the study. After 96 h of DEX treatment, there was also a significant decrease in adult hepatic CBG mRNA abundance. We conclude that glucocorticoids increase fetal plasma CBG in part by increased hepatic biosynthesis. It may also be accentuated by a change in the glycosylation of CBG, but cannot be attributed to transplacental transfer. Furthermore, glucocorticoid treatment exerts opposite effects on CBG biosynthesis in fetal and adult sheep.

Vasopressin receptor expression and mutation analysis in corticotropin-secreting tumors.

Vasopressin is an important regulator of hypothalamo-pituitary-adrenal axis activation, primarily acting through the V3 receptor (V3R). Many patients with ACTH-secreting pituitary adenomas, but not normal individuals, respond to desmopressin, a relatively V2-specific vasopressin agonist, with increased ACTH and cortisol levels. We have searched for mutations of the V3R gene in ACTH-secreting pituitary adenomas and one ectopic ACTH-secreting tumor. No abnormalities were found in 12 tumors studied by PCR-single strand conformation polymorphism (PCR-SSCP) analysis. We then verified by RT-PCR whether the response to desmopressin was due to overexpression of the V3R or abnormal expression of the V2R in the pituitary tumor. We found that the V2R gene was expressed in a number of corticotroph tumors and in the ACTH-secreting ectopic tumor, and that the V3R gene appears to be overexpressed in these tumors. We conclude that V3R mutations are unlikely to be present in the ACTH-secreting tumors we examined, but that the V2R gene is expressed in the majority of the samples tested, and the V3R is expressed in all of these tumors. We speculate that the response to the desmopressin test observed in patients with Cushing's disease may be due to abnormal expression of V3R or V2R in ACTH-secreting tumors.

Expression of glucocorticoid receptor gene isoforms in corticotropin-secreting tumors.

The molecular basis of Cushing's disease is not known. One of the most characteristic features of such tumors is their resistance to corticosteroid feedback at the pituitary level. We have hypothesized that abnormalities of the glucocorticoid receptor (GR) gene might play a role in the development of Cushing's disease via an increase in the relative production of the nonligand-binding splice variant of the GR, GR beta, known to exert dominant negative effects over the ligand-binding isoform, GR alpha. Alternatively, a change in overall GR expression, or mutations of some functional domains of the GR gene, might be involved in the pathogenesis of corticotroph tumors. We studied 22 tumors (17 pituitary ACTH-secreting tumors, 2 ectopic ACTH-producing tumors, 2 prolactinomas, and 1 nonfunctioning adenoma) and three normal pituitaries. RT-PCR was performed with primers specific to GR alpha and GR beta complementary DNA, followed by Southern blotting using an internal probe, and the ratio of the two bands quantitated by densitometry. We also assessed the overall expression of GR relative to the message of both the POMC gene and a housekeeping gene. Single-strand conformation polymorphism analysis of the DNA-binding domain and splice junction region of the gene was also performed. GR alpha messenger RNA was expressed at 37.3-fold +/- 5.7 (range, 32 to 46) excess, as compared with the GR beta subform. This pattern was observed both in the tumor samples and in the normal pituitaries used as controls. A majority of the ACTH-secreting tumors (16/19), including the ectopic secretors, showed variable but increased overall GR expression, whereas 3 tumors showed an expression approximately equivalent to the normal controls; however, no correlation was found between these two groups and the response to the high-dose dexamethasone test, nor was there any correlation with tumor histology. No mutations were found in any of the tumors by PCR-single-strand conformation polymorphism analysis. In conclusion, although both pituitary and ectopic ACTH-secreting tumors are at least partially glucocorticoid-resistant, no significant abnormalities in the relative expression of the two main GR subforms were observed in a series of such tumors. Additionally, mutations of regions critical to normal function of the receptor do not seem to be a frequent event in these tumors.

Expression of the growth hormone secretagogue receptor in pituitary adenomas and other neuroendocrine tumors.

Synthetic GH secretagogues (GHSs; GH-releasing peptides and their nonpeptide mimetics) stimulate GH release, activate the hypothalamo-pituitary-adrenal axis, and release PRL in vivo. Patients with acromegaly show an exuberant GH response to GHSs, whereas patients with pituitary-dependent ACTH-secreting tumors show an exaggerated rise in ACTH and cortisol. We, therefore, studied the presence of GHS receptor (GHS-R) messenger ribonucleic acid (RNA) in 38 human pituitary tumors of different cell types, 3 ectopic ACTH-secreting tumors, a pancreatic gastrinoma, 3 insulinomas, and a non-secreting thymic carcinoid as well as in 7 normal pituitary glands. Certain pituitary tumors were also studied by in vitro cell culture with measurement of secreted GH, ACTH, PRL, FSH, LH, alpha-subunit, and TSH. RNA was extracted from tissue samples and, after RT, a duplex PCR reaction with primers for the GHS-R gene and for the housekeeping gene glyceraldehyde-3-phosphate dehydrogenase was performed, allowing semiquantitation of GHS-R expression. All the somatotroph adenomas (n = 8) showed a 2-10 times higher expression of the GHS-R gene compared to normal pituitaries. Higher than normal expression was shown in 5 of 18 tumors from patients with ACTH-secreting pituitary adenomas and in 1 of 3 ectopic ACTH-secreting carcinoid tumors. Two of the pituitary ACTH-secreting adenoma samples showed completely absent expression of the GHS-R, 8 showed expression similar to that of normal pituitary tissue, and 3 of the corticotroph adenoma tissue samples and 2 ectopic ACTH-secreting tumors showed a very low level of expression. One of 4 prolactinoma samples showed a high level of expression, 1 showed expression similar to that of normal pituitary, and 2 samples showed a very low level of expression. Nonfunctioning pituitary adenoma samples showed either absent or very low level expression of the GHS-R. The pancreatic gastrinoma sample showed expression similar to that of normal pituitary tissue, whereas 3 insulinomas showed low level expression of the GHS-R gene; a nonsecreting thymic carcinoid tumor showed no detectable expression. In summary, although GHS-R messenger RNA is abundant in human somatotroph adenomas, it is also present in other pituitary adenomas, particularly ACTH-secreting tumors. These findings may explain the in vivo responses to GHSs in patients harboring such tumors. It also appears from our study that GHS-R may be expressed in other neuroendocrine tumors.

Vancomycin treatment for enterococcal meningitis.

Although clinical disease due to enterococcus is common, there has been only limited experience in the treatment of central nervous system infections by this pathogen. In particular, there have been few reports regarding the treatment of such infections in the penicillin-allergic individual. We present two cases of meningitis due to enterococci, including one case with a brain abscess, in patients with strong histories of penicillin sensitivity. We treated these patients with vancomycin hydrochloride and an aminoglycoside. Vancomycin with an aminoglycoside seems to be a reasonable treatment for enterococcal central nervous system infections.

Gestational- and labour-associated changes in the relative abundance of prostaglandin G/H synthase-1 and -2 mRNA in ovine placenta.

The aim of this study was to establish the gestational- and labour-associated variation in the relative abundance of prostaglandin synthase-1 (PGHS-1) and prostaglandin synthase-2 (PGHS-2) mRNA in ovine placenta (cotyledons). Cotyledons were collected from non-labouring ewes at 40-145 days of gestation (n = 25) and from ewes in active labour (145-147 days, n = 5). The relative abundance of PGHS-1 and PGHS-2 mRNA transcripts was determined by Northern blot analysis and laser densitometry, using a 2.3 kb sheep and a 1.2 kb mouse cDNA probe respectively. Data were expressed as a ratio of PGHS transcript hybridization/18S rRNA hybridization. During pregnancy, the relative abundance of PGHS-2 mRNA increased sevenfold, from 0.19 +/- 0.04 at 40-85 days (n = 5) to 1.39 +/- 0.05 at 140-145 days (n = 4) (P < 0.01). PGHS-1 mRNA relative abundance did not change significantly (P > 0.05) during gestation. Neither PGHS-1 nor PGHS-2 mRNA relative abundance changed significantly in association with labour onset at term (n = 5) when compared with the relative abundance observed at 140-145 days (n = 4) (P > 0.05). The data obtained in this study are consistent with the hypothesis that PGHS-1 is constitutively expressed in ovine placenta during pregnancy and at the time of labour, and that PGHS-2 is induced during the second half of pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Fungal infections in patients with acute leukemia.

We reviewed the records of 32 patients with acute leukemia and proved invasive fungal infections to determine the clinical and pathologic characteristics of systemic mycosis in patients undergoing intensive induction chemotherapy. The incidence of invasive fungal infections among our patients was at least 27 percent, and Candida and Aspergillus accounted for the majority of these infections. Patients with systemic candidiasis generally had prolonged severe neutropenia, fever refractory to antibiotics, and evidence of mucosal colonization by fungi. At autopsy, Candida was always widely disseminated. Patients with aspergillosis generally had neutropenia, fever, and pulmonary infiltrates at the time of admission to the hospital and, at autopsy, their infections were primarily confined to the lungs. Patients infected with both Candida and Aspergillus had clinical and pathologic findings that were a combination of the features of each type of infection. A diagnosis of invasive fungal infection was established before death in only nine of the patients, all of whom had systemic candidiasis. Four of these patients were successfully treated and survived their hospitalization. The reasons for frequently misdiagnosing and unsuccessfully treating systemic mycosis in patients with acute leukemia are examined, and suggestions are made for improved management of patients at high risk for these infections. These suggestions are based upon recognition of the clinical settings in which fungal infections occur, the aggressive use of invasive diagnostic procedures, and the early empiric use of amphotericin B.

Absent hypoxic and hypercapneic arousal responses in children with myelomeningocele and apnea.

Hypoxic and hypercapneic arousal responses from quiet sleep were tested in seven infants with myelomeningocele and Arnold-Chiari malformation who were symptomatic with apnea and/or hypoventilation. All infants with myelomeningocele required tracheostomy and posterior fossa decompression. Responses were compared with those of nine healthy control infants. To assess hypoxic arousal, inspired PO2 was decreased until the end-tidal (alveolar) PO2 reached 45 mm Hg for a maximum of three minutes. Eleven studies were performed in seven infants with myelomeningocele, and arousal occurred in only two studies (18.2%). Eight of nine control infants aroused to hypoxia (89%). To test hypercapneic arousal, inspired PCO2 was increased until end-tidal PCO2 reached 60 mm Hg for a maximum of three minutes. Eight studies were performed on six infants with myelomeningocele, and arousal occurred in three studies (37.5%). All seven control infants studied aroused to hypercapnea (100%). Three infants with myelomeningocele subsequently died. Infants with myelomeningocele, Arnold-Chiari malformation, and apnea or hypoventilation have arousal deficits to respiratory stimuli.

Expression of menin gene mRNA in pituitary tumours.

OBJECTIVE: Multiple endocrine neoplasia type 1 (MEN 1) is an autosomal dominant inherited disorder characterised by the combined occurrence of parathyroid, endocrine pancreas and anterior pituitary tumours. The gene responsible for MEN 1, the menin gene, a putative tumour-suppressor gene located on human chromosome 11q13, has been cloned. To investigate the role of the menin gene in sporadic anterior pituitary tumorigenesis, its mRNA was assessed in a group of pituitary tumours. METHODS: Menin gene expression, along with glyceraldehyde phosphate dehydrogenase (GAPDH) gene expression, has been studied in a group of normal pituitaries and in 23 pituitary tumours not associated with the MEN 1 syndrome. The pituitary tumours included 4 prolactinomas, 11 growth-hormone-secreting tumours and 8 non-functional tumours. Total RNA was extracted from the normal pituitaries and tumours, and cDNA was synthesised with standard reverse transcriptase methods. Duplex polymerase chain reaction (PCR) was standardised in order to quantify the expression of the menin gene using intron-spanning primers across exons 9 and 10 in relation to the 'house-keeping' gene GAPDH. The PCR products were separated on agarose gel and densitometric analysis of the bands allowed semi-quantification. RESULTS: There was no evidence for a change in menin gene expression in any of the pituitary tumours when compared with normal pituitaries. CONCLUSIONS: These studies complement previous work on mutational analysis, and do not suggest a major role for the menin suppressor gene in sporadic pituitary tumorigenesis.

Peripheral chemoreceptor function in children with myelomeningocele and Arnold-Chiari malformation type 2.

Blunted rebreathing hyperoxic hypercapnic ventilatory and arousal responses are frequent in older children with myelomeningocele (MMC) and Arnold-Chiari malformation type 2 (ACM). In contrast, isocapnic hypoxic rebreathing ventilatory responses are only occasionally affected. Thus, regions mediating the hypoxic ventilatory response appear usually preserved in children with MMC and ACM. Peripheral chemoreceptor function (PCR), however, has not been critically assessed in these children. To study this, PCR was measured in ten children and adolescents with MMC and ACM with normal alveolar ventilation during wakefulness, and in ten sex- and age-matched controls by measuring the ventilatory responses induced by 100% O2 breathing, five tidal breaths of 100% N2, and vital capacity breaths of 15% CO2 in O2. In general, tidal breathing of 100% O2 resulted in smaller decreases in minute ventilation (VE) responses in patients with MMC, although absent VE responses to hyperoxia were found in four patients. Vital capacity breaths of 15% CO2 elicited similar increases in VE in five patients and in ten controls, but no changes in VE were found in the remaining five patients (p < 0.02). Acute hypoxia induced by N2 tidal breathing resulted in significant linear regression correlations between VE and SpO2 in five patients with MMC, while absent responses were measured in those same five patients with absent hypercapnic responses. We conclude that PCR, when assessed by acute hypoxia, hyperoxia, or hypercapnia is abnormal in some children with MMC and ACM, particularly in those demonstrating abnormal ventilation during sleep. We postulate that the large interindividual variability of PCR is dependent on the severity of brainstem involvement of PCR afferents or central respiratory integration sites.

Induction of nitric oxide synthase and interleukin-1beta, but not heme oxygenase, messenger RNA in rat brain following peripheral administration of endotoxin.

Previous studies have suggested that both nitric oxide (NO) and carbon monoxide (CO) are important modulators of the inflammatory response, while more recent data have implicated both gases as regulators of hypothalamic neuroendocrine function, particularly the hypothalamo-pituitary-adrenal axis. We have, therefore, investigated the modulation of the transcripts for the synthetic enzymes for both NO and CO following the intraperitoneal administration of lipopolysaccharide, serotype B5 055, over the course of 24 h. The mRNA for type I or neuronal nitric oxide synthase (nNOS), and type II or inducible (iNOS), and heme oxygenase1 ('inducible') and heme oxygenase2 ('constitutive'), were reverse transcribed to cDNA, amplified by the polymerase chain reaction, and then quantified using a co-amplified internal standard, beta-actin. This allowed for assessment of relative changes in transcript concentration. In addition, these were compared to changes in expression of the cytokine, IL-1beta. Finally, absolute levels of the synthetic enzyme transcripts were assessed by means of co-amplification in the presence of varying amounts of mutant templates in a competitive PCR reaction. Our data revealed rapid induction of IL-1beta, iNOS and HO1 in the liver, returning to baseline at 24 h. In the hypothalamus, all transcripts were present under basal conditions, but only IL-1beta and iNOS were induced by the LPS. We conclude that hypothalamic IL-1beta and iNOS can be induced by a non-lethal dose of endotoxin, and are, thus, in a position to mediate certain of the neuroendocrine consequences to inflammatory stress.