[Neonatal capillary leak syndrome]

Neonatal capillary leak syndrome is a clinical syndrome with definite etiology or predisposing factors and has the manifestations of hypotension, hemoconcentration, hypoproteinemia, and systemic edema. This disease often has critical conditions and may lead to multiple organ failure and even death. There are still controversies over the diagnosis and treatment of this disease. This article summarizes the recent advances in the diagnosis and treatment of neonatal capillary leak syndrome, in order to improve the diagnosis and treatment of this disease among clinicians.

Epidemiologic survey on hospitalized neonates in China

OBJECTIVE

To carry out a nationwide epidemiologic survey on the neonates in urban hospitals with an attempt to understand the disease spectrum and treatment outcomes of hospitalized neonates in China.

METHODS

The clinical data of 43,289 hospitalized neonates from 86 hospitals in 47 Chinese cities (22 provinces) between January 1, 2005 and December 31, 2005 were retrospectively analyzed.

RESULTS

The male:female ratio was 1.73:1. Premature infants accounted for 26.2% of the hospitalized neonates, which was higher than that reported in 2002 (19.7%). The top three diseases during the neonatal period were jaundice, pneumonia, and hypoxic-ischemic encephalopathy. The incidences of pneumonia, meconium aspiration syndrome, and bilirubin encephalopathy in term infants were higher than those in premature infants, while the incidences of asphyxia, respiratory distress syndrome, and pulmonary hemorrhage in term infants were lower than those in premature infants. The incidences of asphyxia, small for gestational age infant, and wet lung were higher in neonates whose mother had pregnancy induced hypertension. The outcomes of these hospitalized neonates included: recovered, 63.9%; improved, 27.3%; discharged due to the family's own decisions, 7.6%, and died, 1.2%. Nearly half (46.4%) of the neonatal death occurred within 24 hrs after admission.

CONCLUSION

The incidence of premature birth shows an increasing trend among hospitalized neonates. Since the neonatal deaths mainly occur within 24 hrs after admission, monitoring during this period should be enhanced.

Severe hyperbilirubinaemia in a Chinese girl with type I Crigler-Najjar syndrome: first case ever reported in Mainland China

Jaundice is common in ethnic Chinese infants, but to our knowledge Crigler-Najjar syndrome (CN syndrome) type I has never been reported in China. A Chinese girl with severe jaundice was recently diagnosed to have CN syndrome type I by analyzing the bilirubin-uridinediphospho (UDP)-glucuronosyltransferase gene (UGT1A1). The patient was homozygous for a nonsense mutation that replaced glutamine (CAG, amino acid 239) with stop codon (TAG) at nucleotide number 715 (715C-->T) in exon 1. No mutation was found in exons 2-5. Her parents were heterozygous for the same mutant. The patient had an average bilirubin level of 300-500 mumol/L and a peak of 701 mumol/L. Daily phototherapy for 15 h was required to keep the bilirubin levels within 280-320 mumol/L. The unconjugated hyperbilirubinaemia apparently resulted from homozygous nonsense mutation of UGT1A1, which could completely abolish the UGT activity towards bilirubin (hepatic glucuronidation) and result in CN syndrome type I. Identification of the genetic defect is very useful for gene therapy, especially for DNA/RNA chimera therapy, and can be used as an antenatal screening test to identify the affected offsprings.

Cerebral intracellular calcium concentrations in asphyxiated rat fetuses resuscitated with oxygen

OBJECTIVE

To investigate the effects of resuscitation with three different oxygen concentrations on cerebral intra- and extra-cellular calcium, sodium and potassium changes in asphyxiated rat fetuses.

METHODS

Fifty-six fetal rats of gestational age of 20 days were randomly assigned into five study groups: sham operation group (control, n = 11), room-air resuscitation group (n = 10), and 3 oxygen-resuscitated groups (n = 14, 11, and 10 respectively). Different inhaled oxygen concentrations and different timings of oxygen delivery were assigned. Except for control all fetal rats were rendered ischemic and hypoxic in utero by interrupting the placental circulation. After re-circulation, intra- and extra-cellular concentrations of calcium, sodium, and potassium in the brains were measured for each individual group.

RESULTS

The mean intracellular free calcium concentration of fetal rat brains was similar for the room-air resuscitation group (552.1 +/- 93.5 nmol/L) and the group resuscitated with 92.8% oxygen (520.6 +/- 79.1 nmol/L) and both were significantly higher than in the control (315.3 +/- 86.9 nmol/L) (P < 0.001). After resuscitation with 65% oxygen, be it instituted before or immediately after hypoxia, their mean intracellular free calcium concentrations in the brain cells (441.5 +/- 47.9 and 452.9 +/- 36.4 nmol/L respectively) were significantly lower than those in the room-air resuscitation (P < 0.01) and 92.8% oxygen group (P < 0.05), though still higher than in the control (P > 0.05). There was no difference in the total concentrations of calcium, sodium, or potassium among all groups.

CONCLUSIONS

Resuscitation with 92.8% oxygen or room air exerted a similar effect on the parameters measured, indicating that resuscitation of asphyxiated neonates using 100% oxygen might not be superior to using room air. Resuscitation with 65% oxygen resulted in lower cerebral intracellular calcium concentrations and might produce a better outcome than using 100% oxygen or room air.

Cryptococcus neoformans resides in an acidic phagolysosome of human macrophages

Recently, we demonstrated that human monocyte-derived macrophages (MDM) treated with chloroquine or ammonium chloride had markedly increased antifungal activity against the AIDS-related pathogen Cryptococcus neoformans. Both of these agents raise the lysosomal pH, which suggested that the increased antifungal activity was a function of alkalinizing the phagolysosome. Moreover, there was an inverse correlation between growth of C. neoformans in cell-free media and pH. These data suggested that C. neoformans was well adapted to survive within acidic compartments. To test this hypothesis, we performed studies to determine the pH of human MDM and neutrophil phagosomes containing C. neoformans. Fungi were labeled with the isothiocyanate derivatives of two pH-sensitive probes: fluorescein and 2',7'-difluorofluorescein (Oregon Green). These probes have pKas of 6.4 and 4.7, respectively, allowing sensitive pH detection over a broad range. The phagosomal pH averaged approximately 5 after ingestion of either live or heat-killed fungi and remained relatively constant over time, which suggested that C. neoformans does not actively regulate the pH of its phagosome. The addition of 10 and 100 microM chloroquine resulted in increases in the phagosomal pH from a baseline of 5.1 up to 6.5 and 7.3, respectively. Finally, by immunofluorescence, colocalization of C. neoformans and the MDM lysosomal membrane protein LAMP-1 was demonstrated, establishing that fusion of C. neoformans-laden phagosomes with lysosomal compartments takes place. Thus, unlike many other intracellular pathogens, C. neoformans does not avoid fusion with macrophage lysosomal compartments but rather resides and survives in an acidic phagolysosome.

Variables affecting production of monocyte chemotactic factor 1 from human leukocytes stimulated with Cryptococcus neoformans

The chemokine monocyte chemoattractant protein 1 (MCP-1) is produced predominantly by mononuclear phagocytes and stimulates recruitment into infected tissues of blood monocytes and T cells. These cell types are thought to be critical to host defenses against infections due to Cryptococcus neoformans, a major cause of disease in persons with AIDS and other disorders of cell-mediated immunity. Accordingly, in the present study, we examined the conditions under which human monocytes and bronchoalveolar macrophages (BAM) are stimulated by C. neoformans to produce MCP-1. C. neoformans was a potent inducer of MCP-1 release from monocytes, with levels of chemokine secreted similar to that seen following stimulation with lipopolysaccharide (LPS). BAM, in contrast, were stimulated by LPS, but not by C. neoformans, to secrete MCP-1. A peak in MCP-1 mRNA was seen 8 h following cryptococcal stimulation of monocytes. Nine strains of C. neoformans stimulated monocytes to release MCP-1, and there was only modest variation between strains. However, when an individual strain was used, the capacity of C. neoformans to stimulate monocyte MCP-1 release did vary, depending upon the conditions used to grow the fungal stimuli. Finally, C. neoformans stimulated comparable quantities of MCP-1 release in monocytes from donors with and without human immunodeficiency virus infection. These data establish C. neoformans as a potent stimulator of MCP-1 in monocytes, but not in BAM. The failure of C. neoformans to stimulate MCP-1 in BAM, if occurring in vivo, could result in a diminished cell-mediated inflammatory response following inhalation of airborne fungi.

Monocyte chemoattractant protein 1 and interleukin-8 production in mononuclear cells stimulated by oral microorganisms

Chemokines are a family of low-molecular-weight proinflammatory cytokines that stimulate recruitment of leukocytes. The chemokines interleukin-8 (IL-8) and monocyte chemoattractant protein 1 (MCP-1) are relatively specific chemoattractants for neutrophils and monocytes, respectively. Chemokine expression contributes to the presence of different leukocyte populations observed in normal and pathologic states. In the present studies, peripheral blood mononuclear cells (PBMC) were stimulated by microbes (Candida albicans, Streptococcus mutans, Porphyromonas gingivalis, and Actinobacillus actinomycetemcomitans) selected based upon their importance as oral pathogens. IL-8 and MCP-1 gene expression and protein release were determined by Northern blot (RNA blot) analysis and enzyme-linked immunosorbent assay. C. albicans, P. gingivalis, and A. actinomycetemcomitans induced high levels of production of both MCP-1 and IL-8. S. mutans was a strong inducer of MCP-1, but it did not stimulate significant production of IL-8. C. albicans, S. mutans, and A. actinomycetemcomitans were 500 to 5,000 times more potent than P. gingivalis in terms of MCP-1 production. In general, the microbe-to-PBMC ratios required for maximum gene expression of MCP-1 were lower than those for IL-8. However, for actual protein release of MCP-1 versus IL-8, differences in the effects of various microbe concentrations were observed only for A. actinomycetemcomitans. These results demonstrate that different oral pathogens induce specific dose-dependent patterns of chemokine gene expression and release. Such patterns may help explain the immunopathology of oral infections, particularly with regard to inflammatory leukocyte recruitment.

Effects of interleukin-10 on human peripheral blood mononuclear cell responses to Cryptococcus neoformans, Candida albicans, and lipopolysaccharide

Deactivation of mononuclear phagocytes is critical to limit the inflammatory response but can be detrimental in the face of progressive infection. We compared the effects of the deactivating cytokine interleukin 10 (IL-10) on human peripheral blood mononuclear cell (PBMC) responses to lipopolysaccharide (LPS), Cryptococcus neoformans, and Candida albicans. IL-10 effected dose-dependent inhibition of tumor necrosis factor alpha (TNF-alpha) release in PBMC stimulated by LPS and C. neoformans, with significant inhibition seen with 0.1 U/ml and greater than 90% inhibition noted with 10 U/ml. In contrast, even at doses as high as 100 U/ml, IL-10 inhibited TNF-alpha release in response to C. albicans by only 50%. IL-10 profoundly inhibited release of IL-1beta from PBMC stimulated by all three stimuli. TNF-alpha mRNA and release was inhibited even if IL-10 was added up to 8 h after cryptococcal stimulation. In contrast, inhibition of IL-1 beta mRNA was of lesser magnitude and occurred only when IL-10 was added within 2 h of cryptococcal stimulation. IL-10 inhibited translocation of NF-kappaB in response to LPS but not the fungal stimuli. All three stimuli induced IL-10 production in PBMC, although over 10-fold less IL-10 was released in response to C. neoformans compared with LPS and C. albicans. Thus, while IL-10 has deactivating effects on PBMC responses to all three stimuli, disparate stimulus- and response-specific patterns of deactivation are seen. Inhibition by IL-10 of proinflammatory cytokine release appears to occur at the level of gene transcription for TNF-alpha and both transcriptionally and posttranscriptionally for IL-1beta.