Acute diarrhea in Paraguayan children population: detection of rotavirus electropherotypes

Group A rotavirus infections were detected in 93 of 410 fecal samples from children with acute diarrhea, admitted in three main hospitals of Asunción, Paraguay, from August 1998 to August 2000. Most of the rotavirus-infected patients were admitted during the winter season in the three epidemic years. The rotavirus infection rate was highest in infants from 6 to 23 months of age. In the 93 samples examined, 10 different rotavirus electropherotypes were recognized, but two of them largely predominated. Only one sample showed a short electropherotype pattern, thus indicating a minor involvement of the rotavirus subgroup I in rotaviral acute diarrhea in the area and the time during which the survey was carried out.

Intussusception in an adult patient with severe hyperglycaemia--a case report

AIMS

To report a case of adult intussusception associated with and possibly induced by acute hyperglycaemia.

METHODS

We present the first case report of adult intussusception with severe hyperglycaemia. Clinical and laboratory data together with radiological findings are presented with a brief review of the literature.

RESULTS

A 20-year-old man with no past medical history presented with abdominal pain for 2 days. The patient was severely hyperglycaemic with blood glucose of 72.7 mmol/l (normal 3.3-6.1 mmol/l), a pH of 7.2 and serum potassium of 6.5 mmol/l (normal 3.5-5.0 mmol/l). He had a computed tomography (CT) scan of the abdomen that revealed small bowel intussusception. Upon treatment of his hyperglycaemia, the patient's abdominal pain completely resolved. Follow up abdominal CT revealed complete resolution of the previously detected intussusception.

CONCLUSION

Clinicians should be aware of the potential for the occurrence of intussusception in severely hyperglycaemic patients. Correction of hyperglycaemia could lead to resolution of the intussusception without surgical intervention. Possible effects of hyperkalaemia and/or acidosis on gastrointestinal motility should also be considered.

Comparison of endoscopic sinus surgery with and without image guidance

BACKGROUND

Image guidance based on preacquired computed tomography scans of the patient is a technique used to assist the physician during endoscopic sinus surgery (ESS). This study seeks to compare ESS with and without image guidance, analyzing a number of parameters that can impact on efficacy.

METHODS

Retrospective chart review took place at a tertiary care referral center. The study group consisted of 97 consecutive patients confirmed to have undergone ESS using an electromagnetic intraoperative image guidance system (IGS). The control group consisted of 61 consecutive patients who underwent ESS, before the IGS was available at the study hospital. The main outcomes measured were analysis of patient profile, including coexisting conditions such as asthma and polyposis, assessment of which specific sinuses underwent surgical treatment; major and minor complications; estimated blood loss (EBL); operative time; and the need for repeat surgery.

RESULTS

The IGS group had 74% of patients with polyposis; more sinuses, on average, which underwent surgical revision; one major and three minor complications; an average EBL of 134 cc, an average procedure time of 154 minutes; and one patient who needed repeat surgery in a 3-month follow-up period. The non-IGS group had 40% of patients with polyposis; seven major complications and one minor complication; an average EBL of 94 cc; and three patients who needed repeat surgery within 3 months.

CONCLUSIONS

The use of an IGS for endoscopic sinus surgery may reduce the complications associated with the procedure and allow for a more thorough operation. However, operative time and EBL may be increased.

New farnesylhydroquinone glycosides from the gorgonian Euplexaura anastomosans

Euplexides F (3) and G (4), novel farnesylhydroquinone glycosides, have been isolated as minor constituents of the gorgonian Euplexaura anastomosans. The structures of these compounds have been determined by combined spectroscopic methods. These compounds exhibited moderate cytotoxicity and inhibitory activity against PLA2.

Fabrication of ultralow-loss Si/SiO(2) waveguides by roughness reduction

We demonstrate 0.8-dB/cm transmission loss for a single-mode, strip Si/SiO(2) waveguide with submicrometer cross-sectional dimensions. We compare the conventional waveguide-fabrication method with two smoothing technologies that we have developed, oxidation smoothing and anisotropic etching. We observe significant reduction of sidewall roughness with our smoothing technologies, which directly results in reduced scattering losses. The rapid increase in the scattering losses as the waveguide dimension is miniaturized, as seen in conventionally fabricated waveguides, is effectively suppressed in the waveguides made with our smoothing technologies. In the oxidation smoothing case, the loss is reduced from 32 dB/cm for the conventional fabrication method to 0.8 dB/cm for the single-mode waveguide width of 0.5 microm . This is to our knowledge the smallest reported loss for a high-index-difference system such as a Si/SiO(2) strip waveguide.

Solution structure of p21(Waf1/Cip1/Sdi1) C-terminal domain bound to Cdk4

Cyclin-dependent kinase (Cdk) inhibitor p21(Waf1/Cip1/Sdi1), a multifunctional protein, has a major role as tumor suppressor, mediating G1/S arrest through inhibition of Cdks. Recent biological studies of Cyclin D1/Cdk4 have proposed that p21 C-terminal domain (p21(CT)) plays a key role as a potent Cdk4 inhibitor. We report here solution structures of p21(CT) for both the free and Cdk4-bound forms using 2D transferred NOE spectroscopy and dynamical simulated annealing calculations. Even though p21(CT) peptide is very flexible in the free state, when it bound to Cdk4, the structure becomes well structured in the binding domain. Therefore we propose that p21(CT) experiences an extensive conformational change upon Cdk4 binding. This structural change of p21(CT) may suggest the molecular mechanism of p21 for specificity and inhibition mode to assemble different cyclin-Cdk complexes. Especially, our data suggests that the D(149)FYHSKRR(156) region of p21 is critical for Cdk4 binding, indicating that the major driving force for complex originates from hydrophobic interaction between p21 and Cdk4.

New steroidal alkaloids from an undescribed sponge of the genus Corticium

Two new steroidal alkaloids, along with a previously reported one of the plakinamine class, were isolated from the sponge Corticium sp. collected from Guam. The structures of the new compounds were determined by combined spectroscopic methods. These compounds exhibited moderate cytotoxicity and antifungal activity as well as DNA- and RNA-cleaving activities.

Transient dissociation of polyribosomes and concurrent recruitment of calreticulin and calmodulin transcripts in gravistimulated maize pulvini

The dynamics of polyribosome abundance were studied in gravistimulated maize (Zea mays) stem pulvini. During the initial 15 min of gravistimulation, the amount of large polyribosomes transiently decreased. The transient decrease in polyribosome levels was accompanied by a transient decrease in polyribosome-associated mRNA. After 30 min of gravistimulation, the levels of polyribosomes and the amount of polyribosome-associated mRNA gradually increased over 24 h up to 3- to 4-fold of the initial value. Within 15 min of gravistimulation, total levels of transcripts coding for calreticulin and calmodulin were elevated 5-fold in maize pulvinus total RNA. Transcripts coding for calreticulin and calmodulin were recruited into polyribosomes within 15 min of gravistimulation. Over 4 h of gravistimulation, a gradual increase in the association of calreticulin and calmodulin transcripts with polyribosomes was seen predominantly in the lower one-half of the maize pulvinus; the association of transcripts for vacuolar invertase with polyribosomes did not change over this period. Our results suggest that within 15 min of gravistimulation, the translation of the majority of transcripts associated with polyribosomes decreased, resembling a general stress response. Recruitment of calreticulin and calmodulin transcripts into polyribosomes occurred predominantly in the lower pulvinus one-half during the first 4 h when the presentation time for gravistimulation in the maize pulvinus is not yet complete.

Transient dissociation of polyribosomes and concurrent recruitment of calreticulin and calmodulin transcripts in gravistimulated maize pulvini

The dynamics of polyribosome abundance were studied in gravistimulated maize (Zea mays) stem pulvini. During the initial 15 min of gravistimulation, the amount of large polyribosomes transiently decreased. The transient decrease in polyribosome levels was accompanied by a transient decrease in polyribosome-associated mRNA. After 30 min of gravistimulation, the levels of polyribosomes and the amount of polyribosome-associated mRNA gradually increased over 24 h up to 3- to 4-fold of the initial value. Within 15 min of gravistimulation, total levels of transcripts coding for calreticulin and calmodulin were elevated 5-fold in maize pulvinus total RNA. Transcripts coding for calreticulin and calmodulin were recruited into polyribosomes within 15 min of gravistimulation. Over 4 h of gravistimulation, a gradual increase in the association of calreticulin and calmodulin transcripts with polyribosomes was seen predominantly in the lower one-half of the maize pulvinus; the association of transcripts for vacuolar invertase with polyribosomes did not change over this period. Our results suggest that within 15 min of gravistimulation, the translation of the majority of transcripts associated with polyribosomes decreased, resembling a general stress response. Recruitment of calreticulin and calmodulin transcripts into polyribosomes occurred predominantly in the lower pulvinus one-half during the first 4 h when the presentation time for gravistimulation in the maize pulvinus is not yet complete.

Molecular cloning and characterization of PELP1, a novel human coregulator of estrogen receptor alpha

Nuclear hormone receptors (NRs) are transcription factors whose activity is regulated by ligands and by coactivators or corepressors. We report the characterization of a new NR coregulator: proline-, glutamic acid-, leucine-rich protein 1 (PELP1), a novel human protein that comprises 1,282 amino acids and is localized on chromosome 17. The primary structure of PELP1 consists of several motifs present in most transcriptional regulators including nine NR-interacting boxes (LXXLL motifs), a zinc finger, and glutamic acid- and proline-rich regions. We demonstrate that PELP1 is a coactivator of estrogen receptor alpha (ERalpha). PELP1 enhances 17beta-estradiol-dependent transcriptional activation from the estrogen response element in a dose-dependent manner. PELP1 interacts with ERalpha and also with general transcriptional coactivators p300 and cAMP response element-binding protein-binding protein. PELP1 was differentially expressed in various human and murine tissues with the highest expression levels in the testes, mammary glands, and brain. We also provide evidence supporting the developmental regulation of PELP1 expression in murine mammary glands, the detectable expression of PELP1 in human mammary cancer cell lines, and the enhanced expression of PELP1 in human breast tumors. These findings suggest that PELP1 is a novel coregulator of ERalpha and may have a role in breast cancer tumorigenesis.

Immunobead RT-PCR versus regular RT-PCR amplification of CEA mRNA in peripheral blood

PURPOSE

The reverse transcription polymerase chain reaction (RT-PCR) amplification of tumor-specific mRNA has been used for the detection of cancer cells in peripheral blood. More recently, an immunomagnetic isolation and reverse transcription polymerase chain reaction (immunobead RT-PCR) was developed which has reportedly significant advantages over the previous RT-PCR analysis. In our study, we compared these two methods using a model set of peripheral blood containing tumor cells under standardized conditions.

MATERIAL AND METHODS

In order to compare the false positive rate, normal peripheral blood samples from five volunteers were analyzed by both methods. A model set of peripheral blood containing tumor cells was established by adding SNUC4 human colon cancer cells to peripheral blood collected from normal volunteers not showing any nonspecific bands upon electrophoresis of the PCR products. RT-PCR amplification of carcinoembryonic antigen (CEA) mRNA was done with total RNA and mRNA prepared from this model sample. In immunobead RT-PCR analysis, mRNA was prepared from the cells isolated with anti-CEA antibody-coated magnetic beads or anti-Ber-EP4 antibody-coated magnetic beads before the RT-PCR analysis.

RESULT

The immunobead RT-PCR yielded no non-specific band, while the regular RT-PCR using total RNA did show non-specific band formation in all five samples. When mRNA rather than total RNA was used, nonspecific bands were formed in three of the five samples. Immunobead RT-PCR allowed the detection of 10(1) tumor cells in 1 ml of peripheral blood. The regular RT-PCR analysis had a detection limit of 10(2) tumor cells in 1 ml of peripheral blood.

CONCLUSION

The immunobead RT-PCR proved to be more sensitive and specific than the regular RT-PCR at least in our model system.

Solution structure of the dimeric cytoplasmic domain of syndecan-4

The syndecans, transmembrane proteoglycans which are involved in the organization of cytoskeleton and/or actin microfilaments, have important roles as cell surface receptors during cell-cell and/or cell-matrix interactions. Since previous studies indicate that the function of the syndecan-4 cytoplasmic domain is dependent on its oligomeric status, the conformation of the syndecan-4 cytoplasmic domain itself is important in the understanding of its biological roles. Gel filtration results show that the syndecan-4 cytoplasmic domain (4L) itself forms a dimer stabilized by ionic interactions between peptides at physiological pH. Commensurately, the NMR structures demonstrate that syndecan-4L is a compact intertwined dimer with a symmetric clamp shape in the central variable V region with a root-mean-square deviation between backbone atom coordinates of 0.95 A for residues Leu(186)-Ala(195). The molecular surface of the 4L dimer is highly positively charged. In addition, no intersubunit NOEs in membrane proximal amino acid resides (C1 region) have been observed, demonstrating that the C1 region is mostly unstructured in the syndecan-4L dimer. Interestingly, two parallel strands of 4L form a cavity in the center of the dimeric twist similar to our previously reported 4V structure. The overall topology of the central variable region within the 4L structure is very similar to that of 4V complexed with the phosphatidylinositol 4,5-bisphosphate; however, the intersubunit interaction mode is affected by the presence of C1 and C2 regions. Therefore, we propose that although the 4V region in the full cytoplasmic domain has a tendency for strong peptide--peptide interaction, it may not be enough to overcome the repulsion of the C1 regions of syndecan-4L.

Adaptation in spiking neurons based on the noise shaping neural coding hypothesis

Shin, Koch and Douglas [Shin, J., Koch, C., & Douglas, R. (1999). Adaptive neural coding dependent on the time-varying statistics of the somatic input current. Neural Computation, 11, 1983-2003] proposed an adaptive neural coding model that makes spiking neurons adapt its input/output relation to the stimulus statistics. In a surprisingly precise manner, the adaptive neural coding model has been supported by recent experiments. However, the previous report has two problems: (a) although the adaptive neural coding model was developed based on the noise shaping neural coding hypothesis, their connection was not explained clearly in the previous report; and (b) the previous model did not suggest a biologically plausible method to estimate the stimulus mean and variance from spike-evoked intracellular calcium concentration. In this paper, I present how the noise shaping neural coding hypothesis produced such a precise model without any available experimental data at that time. Moreover, I propose a computational model for a biologically plausible signal statistics extraction from spike-evoked intracellular calcium concentration. An asymmetry in contrast adaptation time between increasing and decreasing variance, observed in biological experiments, is explained using the signal statistics extraction method. In addition, a new perspective on the relationship between the spike train of spiking neurons and EEG (or local field potential (LFP)) is suggested based on the noise shaping neural coding hypothesis.

Adaptor protein Lad relays PDGF signal to Grb2 in lung cells: a tissue-specific PDGF signal transduction

Lad was previously identified as an adaptor protein binding to the SH2 domain of Lck (1). Specific detection of Lad mRNA in lung cells, as well as, in T cells led us to investigate the signaling pathways regulating Lad in lung cells. We found that (i) upon PDGF stimulation, Lad expression is induced in lung cells, especially in the bronchial epithelial cells; (ii) Lad is tyrosine phosphorylated upon PDGF stimulation and is associated with PDGF receptor; (iii) upon PDGF stimulation, Grb2 is recruited to Lad in human embryonic lung cells; (iv) overexpression of Lad elevated AP-1 promoter activity by two- to threefold, whereas dominant negative Lad abrogated PDGF-dependent activation of AP-1 promoter. These results provide a novel mechanism of PDGF-dependent signaling, in which Lad acts as an adaptor in a tissue-specific manner, linking PDGF signal to Grb2 and subsequent activation of AP-1.

New triterpenoid saponins from the sponge Erylus nobilis

Erylosides G--J (1--4), four new triterpenoid saponins, were isolated from the sponge Erylus nobilis collected from Jaeju Island, Korea. On the basis of the results of combined chemical and spectral analyses, the structures of the aglycones were determined to be lanostane-based, modified penasterols. The oligosaccharide portions were composed of one unit each of L-arabinose, D-galactose, and 2-N-acetyl-D-glucosamine (1 and 3) or two units of L-arabinose and one unit of 2-N-acetyl-D-glucosamine (2 and 4). These compounds exhibited moderate cytotoxicty against a human leukemia cell line.

Treatment of vitamin K deficiency in cystic fibrosis: Effectiveness of a daily fat-soluble vitamin combination

OBJECTIVE

Patients with cystic fibrosis (CF) and pancreatic insufficiency (PI) commonly have vitamin K deficiency, and those with CF-associated liver disease (CFLD) have universal vitamin K deficiency. We evaluated the effectiveness of an oral fat-soluble vitamin combination (ADEKs) to treat patients with vitamin K deficiency.

STUDY DESIGN

Patients with PI and CF (mean age, 15 years; range, 0.6 to 46 years) including 6 with advanced CFLD were prospectively enrolled in a study of a fat-soluble vitamin combination taken on a daily basis. None had received vitamin K supplementation for at least 4 months before the study. Fat-soluble vitamin combination supplementation was given for a minimum of 4 months; the mean vitamin K intake was 0.18 mg/d (SD = 0.1, range, 0 to 0.3). The primary outcome was change in plasma PIVKA-II (prothrombin in vitamin K absence).

RESULTS

Before supplementation 58 (81%) of 72 patients had abnormal PIVKA-II levels (>2.9 ng/mL). After supplementation 29 (40%) had abnormal PIVKA-II levels (P =.001). All 6 patients with advanced CFLD had abnormal PIVKA-II levels (median, range of 20.8, 5.5 to 55 ng/mL) before treatment, which corrected to normal in 50% (4.1, 2.1 to 65 ng/mL). Four patients, 2 with CFLD, had a prolonged prothrombin time (>13.5 seconds) at both time periods.

CONCLUSIONS

An oral fat-soluble vitamin combination with a modest amount of vitamin K can, as a daily supplement, improve the PIVKA-II levels in patients with PI and CF.

Solution structure, backbone dynamics, and stability of a double mutant single-chain monellin. structural origin of sweetness

Single-chain monellin (SCM), which is an engineered 94-residue polypeptide, has been characterized as being as sweet as native two-chain monellin. Data from gel-filtration high performance liquid chromatography and NMR has proven that SCM exists as a monomer in aqueous solution. In order to determine the structural origin of the taste of sweetness, we engineered several mutant SCM proteins by mutating Glu(2), Asp(7), and Arg(39) residues, which are responsible for sweetness. In this study, we present the solution structure, backbone dynamics, and stability of mutant SCM proteins using circular dichroism, fluorescence, and NMR spectroscopy. Based on the NMR data, a stable alpha-helix and five-stranded antiparallel beta-sheet were identified for double mutant SCM. Strands beta1 and beta2 are connected by a small bulge, and the disruption of the first beta-strand were observed with SCM(DR) comprising residues of Ile(38)-Cys(41). The dynamical and folding characteristics from circular dichroism, fluorescence, and backbone dynamics studies revealed that both wild type and mutant proteins showed distinct dynamical as well as stability differences, suggesting the important role of mutated residues in the sweet taste of SCM. Our results will provide an insight into the structural origin of sweet taste as well as the mutational effect in the stability of the engineered sweet protein SCM.

New lactone-containing metabolites from a marine-derived bacterium of the genus Streptomyces

Six novel metabolites containing a lactone moiety as a common structural feature, along with the previously described (-)-blastmycinolactol, have been isolated from the cultivation broth of a bacterium of the genus Streptomyces isolated from marine sediment. On the basis of the results of combined spectroscopic analysis, the structures of the new compounds have been determined as butenolides and 3-hydroxy-gamma-butyrolactones.

A single trial analysis of hippocampal theta frequency during nonsteady wheel running in rats

It has been suggested that hippocampal theta rhythm codes some aspects of motor behavior, but previous studies of the correlation between theta frequency and steady whole body locomotion speed using both linear tracks and wheels have provided inconsistent if not contradictory results. Because the relationship between temporal dynamics of theta frequency and non-steady (or dynamic) whole body locomotion speed can help clarify this issue, single trials of hippocampal EEG were analyzed together with nonsteady wheel running speed recorded during rats perform spontaneous normal locomotion in a wheel. Changes in theta frequency within single trials show positive or negative correlation with nonsteady wheel running speed. As the mean running speed increases and the standard deviation of running speed decreases in a single trial, the correlation between temporal dynamics of theta frequency and nonsteady wheel running speed within the single trial tends to be positive. In addition, we found that the amount of deceleration is also related to the polarity of the correlation coefficients.

New xenicane diterpenoids from the gorgonian Acalycigorgia inermis

Eight diterpenes and norditerpenes including five new xenicane metabolites (4--8) have been isolated from the gorgonian Acalycigorgia inermis. The structures of these compounds have been determined by combined spectroscopic analysis. The new compounds exhibited significant cytotoxicity against a human leukemia cell-line.