Characterization of the human and mouse sphingosine 1-phosphate receptor, S1P5 (Edg-8): structure-activity relationship of sphingosine1-phosphate receptors

Five G protein-coupled receptors (S1P(1)/Edg-1, S1P(3)/Edg-3, S1P(2)/Edg-5, S1P(4)/Edg-6, and S1P(5)/Edg-8) for the intercellular lipid mediator sphingosine 1-phosphate have been cloned and characterized. We found human and mouse sequences closely related to rat S1P(5) (97% identical amino acids) and report now the characterization of the human and mouse S1P(5) gene products as encoding sphingosine 1-phosphate receptors. When HEK293T cells were cotransfected with S1P(5) and G protein DNAs, prepared membranes showed sphingosine 1-phosphate concentration-dependent increases in [gamma-(35)S]GTP binding (EC(50) = 12.7 nM). The lipid mediator inhibited forskolin-driven rises in cAMP by greater than 80% after introduction of the mouse or human S1P(5) DNAs into rat hepatoma RH7777 cells (IC(50) = 0.22 nM). This response is blocked fully by prior treatment of cultures with pertussis toxin, thus implicating signaling through G(i/o)alpha proteins. Northern blot analysis showed high expression of human S1P(5) mRNA in spleen, corpus collosum, peripheral blood leukocytes, placenta, lung, aorta, and fetal tissues. Mouse S1P(5) mRNA is also expressed in spleen and brain. Finally, we found that one enantiomer of a sphingosine 1-phosphate analogue wherein the 3-hydroxyl and 4,5-olefin are replaced by an amide functionality shows some selectivity as an agonist S1P(1) and S1P(3) vs S1P(2) and S1P(5).

Sieve analysis: methods for assessing from vaccine trial data how vaccine efficacy varies with genotypic and phenotypic pathogen variation

A key component in the evaluation of efficacy of a vaccine to protect against disease caused by an antigenically diverse infectious pathogen in a preventative vaccine trial is assessing how vaccine-induced protection depends on genotypic and phenotypic variations of the exposing pathogen. This assessment is made by comparing pathogen isolates between infected vaccinated subjects and infected unvaccinated subjects. A survey of efficacy trial reports reveals a lack of systematic, quantitative investigation in this question. Analysis tools for testing if vaccine protection against disease is superior against some pathogen strains, and for estimating the magnitude of this differential vaccine protection, are described. The broad applicability of the methods is illustrated through analysis of isolates taken from persons infected while participating in vaccine trails for cholera, HIV-1, hepatitis B, rotavirus, and pneumococcus. These analyses reveal intriguing trends for Genentech's monovalent rgp120 HIV-1 vaccine, for two whole-killed-cell oral cholera vaccines, and for other vaccines.

Using (1)H magnetic resonance imaging and complementary analytical techniques to characterize developmental changes in the Zantedeschia Spreng. tuber

Nuclear magnetic resonance imaging (MRI) and complementary analytical techniques were used to examine tissue structure and developmental changes occurring during active growth in the root tuber of ZANTEDESCHIA: Spreng. cv. Chianti, a commercially significant cut flower. Plants were observed during the period of leaf senescence and tuberization at the end of the first growth cycle of micropropagated plantlets and, following cool storage to break endodormancy, during development occurring after the replanting of ecodormant tubers. MRI distinguished two distinct regions within the tuber, and the differences in the binding state of water in the two regions were reflected in differences in tissue morphology and function. An abundance of free water was observed in tissue comprised of large parenchyma cells, at the base of the tuber. This tissue appeared to be involved in maintaining the viability of the plant during the period of dormancy, a function indicated primarily by increased metabolic activity in this tissue during dormancy, and reduced metabolic activity during periods of active growth. In contrast, water was more tightly bound in tissue comprised of small parenchyma cells. This tissue appeared to operate as a region for dynamic carbohydrate storage. The initial increase in the free water content of this tissue during the growth phase was linked to the mobilization of starch during canopy development. The subsequent decrease in free water in the remainder of the growth period was linked to the reaccumulation of starch while the tuber functioned as a sink for photosynthate prior to canopy senescence.

Antibiotic susceptibility profiles for group B streptococci isolated from neonates, 1995-1998

Antibiotic susceptibility profiles were analyzed for 119 invasive and 227 colonizing strains of group B streptococci isolated from neonates at 6 US academic centers. All strains were susceptible to penicillin, vancomycin, chloramphenicol, and cefotaxime. The rate of resistance to erythromycin was 20.2% and to clindamycin was 6.9%. Resistance to erythromycin increased in 1997. Type V strains were more resistant to erythromycin than were type Ia (P=.003) and type Ib (P=.004) strains and were more resistant to clindamycin than were type Ia (P<.001), type Ib (P=.01), and type III (P=.001) strains. Resistance rates varied with geographic region: in California, there were high rates of resistance to erythromycin and clindamycin (32% and 12%, respectively), and low rates in Florida (8.5% and 2.1%, respectively). Penicillin continues to be the drug of choice for treatment of group B streptococcus infection. For women who are penicillin intolerant, however, the selection of an alternative antibiotic should be guided by contemporary resistance patterns observed in that region.

Group-specific antibody levels surrounding invasive pneumococcal illness in children infected with human immunodeficiency virus

Pneumococcal antibody levels surrounding systemic pneumococcal illness (SPI) were measured in children infected with human immunodeficiency virus (HIV). Archived serum samples were collected from 28 HIV-infected children who had 34 cases of SPI, caused by pneumococcal groups 4, 6, 9, 14, 19, and 23. Serum samples collected within 23 weeks before and 13 weeks after the SPI were assayed by ELISA for antipneumococcal polysaccharide (PnPs) IgG antibody to 6 representative pneumococcal serotypes. There was a wide range (0. 16-30.80 microg/mL) of pre-SPI anti-PnPs antibody levels to the presumed infecting serotypes, with a geometric mean level of 0.83 microg/mL (n=34). Seventy-six percent of the antibody values were <2.0 microg/mL, and 95% were <5.0 microg/mL. Homologous seroresponses (>/=4-fold rise in anti-PnPs antibody) were detected in only 4 (27%) of 15 paired serum samples. Heterologous, noninfecting group seroresponses were detected frequently (72%) in the paired serum samples from these 4 homologous group seroresponders.

Brain trauma in aged transgenic mice induces regression of established abeta deposits

Traumatic brain injury (TBI) increases susceptibility to Alzheimer's disease (AD), but it is not known if TBI affects the progression of AD. To address this question, we studied the neuropathological consequences of TBI in transgenic (TG) mice with a mutant human Abeta precursor protein (APP) mini-gene driven by a platelet-derived (PD) growth factor promoter resulting in overexpression of mutant APP (V717F), elevated brain Abeta levels, and AD-like amyloidosis. Since brain Abeta deposits first appear in 6-month-old TG (PDAPP) mice and accumulate with age, 2-year-old PDAPP and wild-type (WT) mice were subjected to controlled cortical impact (CCI) TBI or sham treatment. At 1, 9, and 16 weeks after TBI, neuron loss, gliosis, and atrophy were most prominent near the CCI site in PDAPP and WT mice. However, there also was a remarkable regression in the Abeta amyloid plaque burden in the hippocampus ipsilateral to TBI compared to the contralateral hippocampus of the PDAPP mice by 16 weeks postinjury. Thus, these data suggest that previously accumulated Abeta plaques resulting from progressive amyloidosis in the AD brain also may be reversible.

Transcription factor nuclear factor-kappa B is activated in neurons after focal cerebral ischemia

Nuclear factor-kappa B (NF-kappaB) is a multisubunit transcription factor that when activated induces the expression of genes encoding acute-phase proteins, cell adhesion molecules, cell surface receptors, and cytokines. NF-kappaB is composed of a variety of protein subunits of which p50-and p65-kDa (RelA) are the most widely studied. Under resting conditions, these subunits reside in the cytoplasm as an inactive complex bound by inhibitor proteins, IkappaB alpha and IkappaB beta. On activation, IkappaB is phosphorylated by IkappaB kinase and ubiquitinated and degraded by the proteasome; simultaneously, the active heterodimer translocates to the nucleus where it can initiate gene transcription. In the periphery, NF-kappaB is involved in inflammation through stimulation of the production of inflammatory mediators. The role of NF-kappaB in the brain is unclear. In vitro, NF-kappaB activation can be either protective or deleterious. The role of NF-kappaB in ischemic neuronal cell death in vivo was investigated. Adult male rats were subjected to 2 hours of focal ischemia induced by middle cerebral artery occlusion (MCAO). At 2, 6, and 12 hours after reperfusion, the expression and transactivation of NF-kappaB in ischemic versus nonischemic cortex and striatum were determined by immunocytochemistry and by electrophoretic mobility gel-shift analysis. At all time points studied, p50 and p65 immunoreactivity was found exclusively in the nuclei of cortical and striatal neurons in the ischemic hemisphere. The contralateral nonischemic hemisphere showed no evidence of nuclear NF-kappaB immunoreactivity. Double immunofluorescence confirmed expression of p50 in nuclei of neurons. Increased NF-kappaB DNA-binding activity in nuclear extracts prepared from the ischemic hemisphere was further substantiated by electrophoretic mobility gel-shift analysis. Because the activation of NF-kappaB by many stimuli can be blocked by antioxidants in vitro, the effect of the antioxidant, LY341122, previously shown to be neuroprotective, on NF-kappaB activation in the MCAO model was evaluated. No significant activation of NF-kappaB was found by electrophoretic mobility gel-shift analysis in animals treated with LY341122. These results demonstrate that transient focal cerebral ischemia results in activation of NF-kappaB in neurons and supports previous observations that neuroprotective antioxidants may inhibit neuronal death by preventing the activation of NF-kappaB.

Traumatic brain injury in young, amyloid-beta peptide overexpressing transgenic mice induces marked ipsilateral hippocampal atrophy and diminished Abeta deposition during aging

Traumatic brain injury (TBI) is an epigenetic risk factor for Alzheimer's disease (AD). To test the hypothesis that TBI contributes to the onset and/or progression of AD-like beta-amyloid peptide (Abeta) deposits, we studied the long-term effects of TBI in transgenic mice that overexpress human Abeta from a mutant Abeta precursor protein (APP) minigene driven by a platelet derived (PD) growth factor promoter (PDAPP mice). TBI was induced in 4-month-old PDAPP and wild type (WT) mice by controlled cortical impact (CCI). Because Abeta begins to deposit progressively in the PDAPP brain by 6 months, we examined WT and PDAPP mice at 2, 5, and 8 months after TBI or sham treatment (i.e., at 6, 9, and 12 months of age). Hippocampal atrophy in the PDAPP mice was more severe ipsilateral versus contralateral to TBI, and immunohistochemical studies with antibodies to different Abeta peptides demonstrated a statistically significant reduction in hippocampus and cingulate cortex Abeta deposits ipsilateral versus contralateral to CCI in 9-12 month-old PDAPP mice. Hippocampal atrophy and reduced Abeta deposits were not seen in hippocampus or cingulate cortex of sham-injured PDAPP mice or in any WT mice. These data suggest that the vulnerability of brain cells to Abeta toxicity increases and that the accumulation of Abeta deposits decrease in the penumbra of CCI months after TBI. Thus, in addition to providing unique opportunities for elucidating genetic mechanisms of AD, transgenic mice that recapitulate AD pathology also may be relevant animal models for investigating the poorly understood role that TBI and other epigenetic risk factors play in the onset and/or progression of AD.

Cytosolic phospholipase A2 is induced in reactive glia following different forms of neurodegeneration

Many recent studies have emphasized the deleterious role of inflammation in CNS injury. Increases in free fatty acids, eicosanoids, and products of lipid peroxidation are known to occur in various conditions of acute and chronic CNS injury, including cerebral ischemia, traumatic brain injury, and Alzheimer's disease. Although an inflammatory response can be induced by many different means, phospholipases, such as cytosolic phospholipase A(2) (cPLA(2)), may play an important role in the production of inflammatory mediators and in the production of other potential second messengers. cPLA(2) hydrolyzes membrane phospholipids and its activity liberates free fatty acids leading directly to the production of eicosanoids. We investigated the cellular localization of cytosolic phospholipase A(2) in the CNS following: (1) focal and global cerebral ischemia, (2) facial nerve axotomy, (3) human cases of Alzheimer's disease, (4) transgenic mice overexpressing mutant superoxide dismutase, a mouse model of amyotrophic lateral sclerosis, and (5) transgenic mice overexpressing mutant amyloid precursor protein, which exhibits age-related amyloid deposition characteristic of Alzheimer's disease. We show that in every condition evaluated, cytosolic phospholipase A(2) is present in reactive glial cells within the precise region of neuron loss. In conditions where neurons did not degenerate or are protected from death, cytosolic phospholipase A(2) is not observed. Both astrocytes and microglial cells are immunoreactive for cytosolic phospholipase A(2) following injury, with astrocytes being the most consistent cell type expressing cytosolic phospholipase A(2). The presence of cytosolic phospholipase A(2) does not merely overlap with reactive astroglia, as reactive astrocytes were observed that did not exhibit cytosolic phospholipase A(2) immunoreactivity. In most conditions evaluated, inflammatory processes have been postulated to play a pivotal role and may even participate in neuronal cell death. These results suggest that cytosolic phospholipase A(2) may prove an attractive therapeutic target for neurodegeneration.

Early initiation of breastfeeding and the risk of infant diarrhea in rural Egypt

BACKGROUND

Initiation of breastfeeding shortly after delivery may enhance breastfeeding's protective effect against diarrhea because of the protective properties of human colostrum contained in early breast milk.

OBJECTIVE

To evaluate whether initiation of breastfeeding within the first 3 days of life, when breast milk contains colostrum, was associated with a lower rate of diarrhea in rural Egyptian infants during the first 6 months of life.

METHODS

Infants initially breastfed (n = 198) were monitored prospectively with twice-weekly home visits to ascertain dietary practices and diarrheal illnesses.

RESULTS

The burden of diarrhea during the first 6 months of life in the cohort was high: seven episodes per child-year of follow-up. Only 151 (76%) infants initiated breastfeeding during the first 3 days of life ("early initiation"). Infants in whom breastfeeding was initiated early had a 26% (95% CI: 2%,44%) lower rate of diarrhea than those initiated late. The protective association between early initiation and diarrhea was independent of the pattern of postinitiation dietary practices and was evident throughout the first 6 months of life.

CONCLUSIONS

Early initiation of breastfeeding was associated with a marked reduction of the rate of diarrhea throughout the first 6 months of life, possibly because of the salutary effects of human colostrum. These data highlight the need for interventions to encourage early initiation of breastfeeding in less developed settings.

Seroprevalence of Helicobacter pylori among Egyptian newborns and their mothers: a preliminary report

Helicobacter pylori is one of the most common human bacterial infections in the world and children in the developing countries acquire H. pylori infection early in life. We prospectively evaluated the prevalence of serum antibodies to H. pylori in a cohort of pregnant women and their offspring. Mothers' sera were collected during the third trimester of pregnancy and sera from their offspring were collected when they were 7-9 months and 18 months of age. Pylori-Stat, a commercially available ELISA kit, was used to detect antibodies to H. pylori in the serum of the subjects tested. Sera from 169 mothers were available for testing and 88% of these samples were positive for anti-H. pylori IgG. Of the 169 children tested, 13% of the infants 7-9 months of age and 25% of the children 18 months of age had serologic evidence of H. pylori infection. These data indicate that infection with H. pylori is common in Egypt and acquisition of infection occurs at a very young age.

Memory-enhancing effects of secreted forms of the beta-amyloid precursor protein in normal and amnestic mice

When administered intracerebroventricularly to mice performing various learning tasks involving either short-term or long-term memory, secreted forms of the beta-amyloid precursor protein (APPs751 and APPs695) have potent memory-enhancing effects and block learning deficits induced by scopolamine. The memory-enhancing effects of APPs were observed over a wide range of extremely low doses (0.05-5,000 pg intracerebroventricularly), blocked by anti-APPs antisera, and observed when APPs was administered either after the first training session in a visual discrimination or a lever-press learning task or before the acquisition trial in an object recognition task. APPs had no effect on motor performance or exploratory activity. APPs695 and APPs751 were equally effective in the object recognition task, suggesting that the memory-enhancing effect of APPs does not require the Kunitz protease inhibitor domain. These data suggest an important role for APPss on memory processes.

Brain trauma induces massive hippocampal neuron death linked to a surge in beta-amyloid levels in mice overexpressing mutant amyloid precursor protein

Although brain trauma is a risk factor for Alzheimer's disease, no experimental model has been generated to explore this relationship. We developed a model of brain trauma in transgenic mice that overexpress mutant human amyloid precursor protein (PDAPP) leading to the appearance of Alzheimer's disease-like beta-amyloid (Abeta) plaques beginning at 6 months of age. We induced cortical impact brain injury in the PDAPP animals and their wild-type littermates at 4 months of age, ie, before Abeta plaque formation, and evaluated changes in posttraumatic memory function, histopathology, and regional tissue levels of the Abeta peptides Abeta1-40 and Abeta1-42. We found that noninjured PDAPP mice had impaired memory function compared to noninjured wild-type littermates (P < 0.01) and that brain-injured PDAPP mice had more profound memory dysfunction than brain-injured wild-type littermates (P < 0.001). Although no augmentation of Abeta plaque formation was observed in brain-injured PDAPP mice, a substantial exacerbation of neuron death was found in the hippocampus (P < 0.001) in association with an acute threefold increase in Abeta1-40 and sevenfold increase in Abeta1-42 levels selectively in the hippocampus (P < 0.01). These data suggest a mechanistic link between brain trauma and Abeta levels and the death of neurons.

Transient global forebrain ischemia induces a prolonged expression of the caspase-3 mRNA in rat hippocampal CA1 pyramidal neurons

The authors recently cloned a cDNA for an ICE/CED3-related cysteine protease from rat brain, which is closely related to human CPP32 (now designated caspase-3). In situ hybridization histochemistry revealed a profound developmental regulation of the caspase-3 transcript in rat brain, with relatively high levels of caspase-3 mRNA observed in neurons of the fetal and neonatal brain and low levels of mRNA in neurons of the adult brain. The authors report that transient forebrain ischemia, which results in a delayed apoptotic death of CA1 pyramidal neurons, results in prolonged expression of caspase-3 mRNA in these same pyramidal neurons. Up-regulation of caspase-3 mRNA in CA1 pyramidal neurons is prominent 24 hours after transient global ischemia, and expression is maintained at higher levels for at least 72 hours after ischemia. However, by 96 hours after ischemia, a marked decrease in caspase-3 mRNA expression is observed in CA1 pyramidal neurons, showing severe degenerative changes (e.g., nuclear condensation). By contrast, there is no change in the expression of a closely related member of caspase family, caspase-2, in CA1 pyramidal neurons after global ischemia. Instead, caspase-2 mRNA is induced in lamina layers of cerebral cortex 24 hours after the ischemia. A selective and prolonged induction of the caspase-3 gene in committed CA1 pyramidal neurons suggests that transcriptional activation of this caspase-3 gene may be involved in the apoptotic cell death cascade of CA1 neurons after transient global ischemia.

Electrocautery versus curette adenoidectomy: comparison of postoperative results

OBJECTIVE

Identify differences in adenoidectomy performed by curettage versus electrocautery ablation.

DESIGN

To receive adenoidectomy by curettage or electrocautery ablation 38 patients undergoing adenoidectomy or adenotonsillectomy were prospectively randomized. The study was completed by 24 patients. All tonsillectomy patients received electrocautery dissection of the tonsils. Preoperative and at least 1 month postoperative video-nasopharyngoscopy was performed. Video tapes were reviewed by the authors blinded to patient identity and procedure to evaluate choanal obstruction. Preoperative and postoperative lateral neck radiographs were obtained. Blood loss and postoperative complications were recorded.

SETTING

A single, tertiary care pediatric facility.

INTERVENTIONS

Electrocautery ablation of the adenoid was performed with suction cautery. Curettage was performed with standard adenoid curettes.

MAIN OUTCOME MEASURED

A grading system for adenoid size was developed using radiographs and endoscopic parameters. The grade of preoperative and postoperative adenoid tissue was compared between the curettage and electrocautery ablation groups. Operative blood loss was compared between the groups. The postoperative course and complications were compared.

RESULTS

The preoperative grade of choanal obstruction in both groups was the same. No differences could be found in the postoperative grade between the curettage and the electrocautery ablation groups. No postoperative complications were recorded in either group. The estimated blood loss in the curettage group was 54.5 ml (S.D. 50.7) while the electrocautery ablation group averaged 3.75 ml (S.D. 6.4; p = 0.0053).

CONCLUSION

There are no differences in the postoperative results of adenoidectomy performed by electrocautery ablation or curettage. There are no complications recorded in either group. Estimated blood loss was lower in the electrocautery ablation group. Decreased blood loss during the procedure makes the electrocautery ablation method of adenoidectomy attractive.

Abdominal ultra sonographic findings detected in the course of a hepatitis survey in an Egyptian rural area

The objective of this study was to determine the prevalence of abnormal findings detected by abdominal ultrasonography (US) in an Egyptian rural area. This study was a part of a community based cross sectional survey for virus hepatitis carried out at Kalama village in Nile Delta, 40 kilometers north of Cairo. People above 10 years of age living in a 10% systemic random sample of houses in the village were subjects of this study. A member of the team carried out US examination of the liver, biliary tree, spleen, kidneys, pancreas, para aortic areas and the pelvis. Examination included morphological assessment and organometry. All results are recorded on images by videoprinter. Abnormalities in abdominal US was detected in 34% of examined cases. Abnormal liver impressions were detected in 28.3% of cases. Ascites was detected in 13 cases (1.8%). Diseases of the gall bladder and kidneys were detected in 2.7% and 2.1%, respectively. US diagnosed pregnancy in 5 women, one of them had a blighted ovum. Some of these abnormalities were detected in subjects with no complaint. It is concluded that abdominal US may be a tool for early detection of asymptomatic disease.

Zyme, a novel and potentially amyloidogenic enzyme cDNA isolated from Alzheimer's disease brain

The deposition of the beta amyloid peptide in neuritic plaques and cerebral blood vessels is a hallmark of Alzheimer's disease (AD) pathology. The major component of the amyloid deposit is a 4.2-kDa polypeptide termed amyloid beta-protein of 39-43 residues, which is derived from processing of a larger amyloid precursor protein (APP). It is hypothesized that a chymotrypsin-like enzyme is involved in the processing of APP. We have discovered a new serine protease from the AD brain by polymerase chain reaction amplification of DNA sequences representing active site homologous regions of chymotrypsin-like enzymes. A cDNA clone was identified as one out of one million that encodes Zyme, a serine protease. Messenger RNA encoding Zyme can be detected in some mammalian species but not in mice, rats, or hamster. Zyme is expressed predominantly in brain, kidney, and salivary gland. Zyme mRNA cannot be detected in fetal brain but is seen in adult brain. The Zyme gene maps to chromosome 19q13.3, a region which shows genetic linkage with late onset familial Alzheimer's disease. When Zyme cDNA is co-expressed with the APP cDNA in 293 (human embryonic kidney) cells, amyloidogenic fragments are detected using C-terminal antibody to APP. These co-transfected cells release an abundance of truncated amyloid beta-protein peptide and shows a reduction of residues 17-42 of Abeta (P3) peptide. Zyme is immunolocalized to perivascular cells in monkey cortex and the AD brain. In addition, Zyme is localized to microglial cells in our AD brain sample. The amyloidogenic potential and localization in brain may indicate a role for this protease in amyloid precursor processing and AD.

Selective loss of neuronal Na+-dependent phosphate cotransporter mRNA in CA1 pyramidal neuron following global ischemia

A recently identified neuronal Na+-dependent phosphate cotransporter (rBNPI) has been shown to import inorganic phosphate (P(i)) required for the production of high-energy phosphates which are vital to neuronal energy metabolism. In the present study, we have examined the expression of rBNPI mRNA in the hippocampus of rats subjected to 30 min of global ischemia by four-vessel occlusion. In situ hybridization reveals that transient forebrain ischemia results in a selective reduction in rBNPI mRNA expression in CA1 pyramidal neurons of the hippocampus. Expression of rBNPI is significantly reduced by 24 h and completely absent at 72 h following global ischemia when CA1 pyramidal neurons begin to show cell damage. By contrast, there is no change in the expression of Nedd2 mRNA, a developmentally regulated cell death gene, in CA1 pyramidal neurons at these same time points. The loss of rBNPI transcripts appears to be selective for CA1 pyramidal neurons since rBNPI mRNA expression is unchanged in neurons of the CA2-CA4 pyramidal cell layers following global ischemia. Our data indicate that an early reduction of rBNPI transcripts may contribute to a reduction in P(i)-dependent energy metabolism or signal transduction which has been reported in CA1 hippocampal neurons following global ischemia.