Mitochondrial-mediated apoptosis in neural stem cells exposed to manganese.

Manganese is an essential nutrient for humans that has to be maintained at proper levels for normal brain functioning. However, manganese also acts as a toxicant to the brain, and several studies have linked exposure to excessive manganese to neurotoxicity in adults. A recent report has suggested that ingesting high doses of manganese via drinking water can impede intellectual functions in children. It is known that during development, the nervous system is particularly vulnerable to different types of injuries and toxicants. Neural stem cells (NSCs) play an essential role in both the developing nervous system and the adult brain where the capacity for self-renewal may be important. In the present study, we have used NSCs to investigate the molecular mechanisms involved in manganese developmental neurotoxicity. The results show that primary cultures of rat embryonic cortical NSCs as well as the murine-derived multipotent NSC line C17.2 undergo apoptotic cell death via a mitochondrial-mediated pathway in response to manganese. Exposed cells exhibit typical apoptotic features, such as chromatin condensation and cell shrinkage, mitochondrial cytochrome c release, activation of caspase-3, and caspase-specific cleavage of the endogenous substrate poly (ADP-ribose) polymerase. In addition, our data also show that reactive oxygen species formation plays a role in the onset of manganese toxicity in NSCs.     

The effect of serotonin and serotonin receptor antagonists on motion sickness in Suncus murinus

In the present study, we investigated the effect of 5-hydroxytryptamine (5-HT) and 5-HT receptor agonists and antagonists on motion sickness in Suncus murinus, and the possibility that the emetic stimulus of 5-HT can alter the sensitivity of the animals to the different emetic stimulus of motion sickness. 5-HT (1.0, 2.0, 4.0 and 8.0 mg/kg ip) induced emesis and that was antagonised by methysergide (1.0 mg/kg ip), the 5-HT(4) receptor antagonist sulphamate[1-[2-[(methylsulphonyl)amino]ethyl]-4-piperidinyl]methyl-5-fluoro-2-methoxy-1H-indole-3-carboxylate (GR125487D; 1.0 mg/kg ip) and granisetron (0.5 mg/kg ip). Pretreatment with 5-HT caused a dose-related attenuation of the emetic response induced by a subsequent motion stimulus, which was not significantly modified by methysergide, granisetron or GR125487D pretreatment. (+)-1-(2,5-Dimethoxy-4-iodophenyl)-2-amino-propane (DOI; 0.5 and 1.0 mg/kg ip), 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT; 0.1 mg/kg ip) but not methysergide, GR125487D or granisetron, attenuated motion-induced emesis, and that was not affected by pretreatment with ketanserin (2.0 mg/kg, ip) or N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cyclohexanecarboxamide trihydrocholoride (WAY-100635; 1.0 mg/kg ip), respectively. Indeed, ketanserin alone (0.1, 0.3, 1.0 and 2.0 mg/kg ip) attenuated motion sickness. These data indicate that 5-HT(1/2), 5-HT(3) and 5-HT(4) receptors are involved in the induction of 5-HT-induced emesis. However, agonist action at the 5-HT(1A/7) and 5-HT(2) receptors, and antagonist action at the 5-HT(2A) receptors can attenuate motion sickness in S. murinus.     

Pleural flap for treating perigraft leak after a modified Blalock-Taussig shunt

Plasa oozing through the graft after a modified Blalock-Taussig shunt is a troublesome complication. We encountered a massive leak following a modified Blalock-Taussig shunt in a 2 1/2 year-old-girl which required reexploration. The leak was treated by wrapping the polytetrafluoroethylene shunt with the parietal pleura flap harvested from the adjacent chest wall. The patient had an uneventful recovery. Covering of the polytetrafluoroethylene shunt with parietal pleura appears to stop plasma leak through the graft following a modified Blalock-Taussig shunt.     

Coexistence of K-ras mutations and HPV infection in colon cancer

Background  

Activation of the ras genes or association with human papillomavirus infection have been extensively studied in colorectal cancer. However, the correlation between K-ras mutations and HPV in colorectal cancer has not been investigated yet. In this study we aimed to investigate the presence of K-ras mutations and their correlation with HPV infection in colon cancer.     

The impact of work-related risk on nurses during the SARS outbreak in Hong Kong

Severe acute respiratory syndrome (SARS) is a highly infectious disease, with high potential for transmission to close contacts, particularly among healthcare workers. This is the first systematic study investigating hospital nurses' physical and psychological health status and the kinds of healthcare used-stratified by the level of contact with SARS patients-during the 2003 outbreak in Hong Kong. Nurses in moderate-risk areas appeared to have more stress symptoms than those working in high-risk areas. It is essential to design hospital support systems and occupational health policy to promote the psychological well-being of nurses during future outbreaks of emerging infections.     

ACE gene insertion/deletion polymorphism in childhood idiopathic nephrotic syndrome

The aim of this study was to determine the distribution of angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism, and its effects on clinical, laboratory, histological findings, treatment responses and progression to end-stage renal disease in childhood idiopathic nephrotic syndrome (NS). 227 children diagnosed with idiopathic NS were included in the study. Eighty-three of patients were steroid resistant and 77 of patients were focal segmental glomerulosclerosis. The control group was consisted of 287 unrelated healthy adult volunteers. ACE gene I/D polymorphism were analyzed by using PCR based method. In the entire group of children with NS, the frequencies of the II, ID, and DD genotypes of ACE gene were 13.7%, 38.3% and 48%, respectively. D allele frequency was higher in NS group than control group (0.67 vs. 0.56, p=0.001). Percentage of frequent relapser patients was found more frequently in ID or DD genotype (38.7%) than II genotype (15%) when only steroid sensitive patients were evaluated (p=0.045). The D-allele frequency was 0.65, 0.69 and 0.68 respectively in focal segmental glomerulosclerosis, biopsy proven minimal change and entire minimal change group (p>0.05) and 0.69 and 0.64 respectively in steroid sensitive and resistant groups (p>0.05). D allele frequency was not significantly different in patients with or without end-stage renal disease (0.64 vs. 0.67 respectively, p>0.005) when 115 patients who were at least five year follow-up were evaluated. The D allele frequency was higher in NS patients than healthy controls and DD or ID genotype was related with frequent relapses. ACE gene I/D polymorphism was not important in laboratory and histological findings and progression of the disease in children with NS.     

Postnatal management of infants with antenatally detected hydronephrosis

With the increasing use of antenatal sonography, fetal hydronephrosis has been reported more frequently. Because of the lack of consensus regarding treatment of these infants, the postnatal approach toward fetal renal pelvis enlargement remains controversial. The aim of this prospective study is to demonstrate the postnatal investigation, treatment, and outcome of infants with prenatally diagnosed hydronephrosis. Infants whose antenatal ultrasound scan showed a fetal renal pelvis of 5 mm or greater were investigated postnatally using ultrasound (US) and voiding cystourethrography. When indicated, isotope studies and intravenous urograms were also performed. We followed prospectively neonates with antenatally diagnosed hydronephrosis and recommended management guidelines on the basis of our findings. In 156 neonates (193 kidney units) that were found to have hydronephrosis, the average gestational age at which the diagnosis was made was 32.94±5.10 weeks. The mean duration of postnatal follow-up was 26.3±13.56 months (range 3–60 months). The mean APPD of the fetal renal pelvis was 10.35±3.24 mm (5–9 mm in 84 kidneys, 10–14 mm in 96 kidneys and 15 mm in 13 kidneys). Of the 193 kidney units, 145 units were found to be pathological. The most common detected underlying abnormalities were ureteropelvic junction obstruction (in 91 kidneys; 62.7%) and vesicoureteral reflux (in 24 kidneys; 16.6%). Postnatally, 23 (45%) of 51 patients whose first US was normal were diagnosed postnatally as having urinary tract abnormality. There was a negative correlation between APPD and the rate of spontaneous resolution and positive correlation between APPD and the rate of surgery (P<0.01). In conclusion, because it is not possible to determine an upper limit of normal for the antenatal renal pelvis, any baby with AH should not be considered clinically insignificant. Infants with antenatal renal pelvis measurements 5 mm should be investigated postnatally. A normal postnatal ultrasound scan does not preclude the presence of urinary tract abnormality.