An illustrated identification key to four different species of adult Dinoderus (Coleoptera: Bostrichidae), commonly attacking dried cassava chips in West Africa

Bostrichids of the genus Dinoderus are commonly found as pests of dried cassava chips in West Africa. An illustrated key facilitating the identification of the four most frequent African species, i.e. D. bifoveolatus (Wollaston), D. minutus (Fabricius), D. porcellus Lesne, and D. oblongopunctatus Lesne is presented.

Orofacial analysis on the Adriatic Islands: 1. The island of Hvar as a model for odontogenetic researches

This paper presents a preliminary orofacial analysis of a subadult population of Hvar, a Croatian island in the Adriatic. Its population represents one of the last genetic isolates in Europe and has therefore been the object of intensive crossdisciplinary research over the last 30 years. We focussed on the coefficient of endogamy on the one hand and malocclusal-related caries on the other hand, and expected differences in the latter between subgroups of the population. We analyzed 224 dental casts from children all over the island and found multiple caries in approximal surfaces in 55 percent of the children, but no significant differences between the subpopulations. Instead, significantly more caries affection was found in the boys than in the girls. The percentage of general caries affection is fairly high, even when compared to other isolated populations; it may be due to environmental influence. This would be consistent with the other results, which have putatively been caused by complex environmental influences and not solely by genetic components.

Granulocyte macrophage-colony stimulating factor stimulates secretion of chemoattractive cytokines by peritoneal macrophages of CAPD patients

The recruitment of immunocompetent cells to the site of inflammation represents an essential part of the host defense during continuous ambulatory peritoneal dialysis (CAPD)-related peritonitis. Recently, it was shown that intraperitoneal application of granulocyte macrophage-colony stimulating factor (GM-CSF) leads to a marked transient recruitment of macrophages, paralleled by an increase in monocyte chemoattractant protein (MCP)-1. We, therefore, tested the in vitro effect of GM-CSF on the release of the chemotaxins interleukin (IL)-8 and MCP-1 by human peritoneal macrophages. Cells were stimulated with recombinant GM-CSF for 4, 12, and 20 hours in concentrations ranging from 0.1 to 100 pg/mL. Cells stimulated with lipopolysaccharide (LPS) or unstimulated cells served as control. Recombinant GM-CSF at concentrations found during CAPD peritonitis in vivo significantly increased the release of IL-8 and MCP-1 in a time- and dose-dependent manner. The maximum effect of IL-8 was observed directly after cell isolation, and decreased after a culture period of 10 days. Thus, our results indicate that peritoneal macrophages are the potential source of chemokines released upon GM-CSF stimulation.

Nonintrusive optical measurements of aircraft engine exhaust emissions and comparison with standard intrusive techniques

Nonintrusive systems for the measurement on test rigs of aeroengine exhaust emissions required for engine certification (CO, NO(x), total unburned hydrocarbon, and smoke), together with CO(2) and temperature have been developed. These results have been compared with current certified intrusive measurements on an engine test. A spectroscopic database and data-analysis software has been developed to enable Fourier-transform Infrared measurement of concentrations of molecular species. CO(2), CO, and NO data showed agreement with intrusive techniques of approximately ?30%. A narrow-band spectroscopic device was used to measure CO(2) (with deviations of less than ?10% from the intrusive measurement), whereas laser-induced incandescence was used to measure particles. Future improvements to allow for the commercial use of the nonintrusive systems have been identified and the methods are applicable to any measurement of combustion emissions.

Comparing frontal cranial profiles in archaic and modern homo by morphometric analysis

Archaic and modern human frontal bones are known to be quite distinct externally, by both conventional visual and metric evaluation. Internally this area of the skull has been considerably less well-studied. Here we present results from a comparison of interior, as well as exterior, frontal bone profiles from CT scans of five mid-Pleistocene and Neanderthal crania and 16 modern humans. Analysis was by a new morphometric method, Procrustes analysis of semi-landmarks, that permits the statistical comparison of curves between landmarks. As expected, we found substantial external differences between archaic and modern samples, differences that are mainly confined to the region around the brow ridge. However, in the inner median-sagittal profile, the shape remained remarkably stable over all 21 specimens. This implies that no significant alteration in this region has taken place over a period of a half-million years or more of evolution, even as considerable external change occurred within the hominid clade spanning several species. This confirms that the forms of the inner and outer aspects of the human frontal bone are determined by entirely independent factors, and further indicates unexpected stability in anterior brain morphology over the period during which modern human cognitive capacities emerged. Anat Rec (New Anat): 257:217-224, 1999.

Re-evaluation of the endocranial volume of the Guattari 1 Neandertal specimen (Monte Circeo)

The endocranial capacity of Guattari 1 originally was estimated by Sergi as approximately 1.550 cm3. Using three different approaches, a physical endocast, a stereolithographic model, and a virtual endocast, we have estimated the endocranial capacity of Guattari 1 as approximately 1.350 cm3. This paper explains our revision of the estimated endocranial volume of Guattari 1, provides a cautionary case concerning other estimates of endocranial volume, and demonstrates and encourages the use of recent advances in imaging, modeling, and analysis of endocranial volume.

Effects of somatostatin, octreotide and cortistatin on ischaemic neuronal damage following permanent middle cerebral artery occlusion in the rat

This study investigated whether peptides acting at somatostatin receptors, such as somatostatin-14, octreotide or cortistatin-14, can influence the extent of brain damage after focal ischaemia in rats. The intracerebroventricular application of 0.1 or 1.0 nmol somatostatin-14 5 min after middle cerebral artery occlusion significantly reduced the infarct size assessed 7 days after the insult (by 47% and 57% of the saline control), whereas 10.0 nmol had no significant protective effect (9% reduction). A similar dose/response relationship was obtained after intracerebroventricular injection of octreotide. The lower doses of 0.1 or 1.0 nmol afforded significant neuroprotection (reduction of the infarct size by 72 and 57%), whereas 10 nmol actually increased the infarct size up to 348%. Cortistatin-14 (10 nmol) decreased the ischaemic damage by 52%. For comparison with the neuropeptides acting on somatostatin receptors, the kappa opiate agonist enadoline (10 nmol) also had a significant protective effect against the development of focal ischaemia; the extent of the brain damage was reduced by 60% after intracerebroventricular injection.

New methods and techniques in anthropology

Since the discovery of the Tyrolean Iceman in 1991, advanced imaging and post-processing techniques have been successfully applied to anthropological research. Among the specific techniques are spiral computed tomography and 3-dimensional reconstructions, which include stereolithographic and fused deposition modeling of volume data sets. The Iceman's skull was the first to be produced using stereolithography; subsequently, it has been successfully applied in preoperative planning. With the advent of high-end performance graphics workstations and biomedical image processing software packages, 3-dimensional reconstructions have become established as routine tools for analyzing volume data sets. These techniques enabled dramatically new insights to be gained in the field of physical anthropology. Computed tomography became the ideal research tool to access the internal structures of various precious fossils without even touching--let alone damaging--them. Among the most precious are specimens from the genus Australopithecus (1.8 Myr-3.5 Myr), as well as representatives of Homo heidelbergensis (200 kyr-600 kyr) and Homo neanderthalensis (40 kyr-100 kyr); such fossils have been CT-scanned during the last five years. The fossils often are filled with a stone matrix or other encrustations. During the post-processing routines, highly advanced algorithms were used to remove these encrustations virtually (the concrete fossils remain untouched). Thus it has been possible to visualize the morphological structures that are hidden by the matrix layer. Some specimens have been partially destroyed, but it has been possible for the missing parts were reconstructed on the computer screen in order to get estimations of brain volume and endocranial morphology, both major fields of interest in physical anthropology. Moreover, the data in computerized form allows new descriptions of morphological structures using geometric morphometrics. Some of the results may change aspects and interpretations in human evolution and approaches to long-standing questions in this field. We subsume the introduction of these new imaging and post-processing techniques into a new field of research: Virtual Anthropology.

The iceman under pressure (Part I): A description of skull deformations due to 5100 years of glacial action

Due to its long deposition in the glacier, the 'Iceman' (an ice-mummy from the Hauslabjoch) has been deformed, notably its skull. We introduce various comparative methods that describe these deformations, assuming they can be ascribed--to a large extent--to glacial action. While pressure is a scalar, the deformations must be described via a 2-tensor strain field (which can be represented by a matrix function value at every point throughout the skull). In this paper, we present the assumed deformations in numerous graphical forms and, furthermore, the limitations in interpretation--including an estimate of statistical variability--that can be revealed by this analysis. These methods, although describing the results of glacial action and implying a 2-tensor strain field (which will be presented in a subsequent paper), do not permit a straightforward reconstruction of the original, underformed skull. These methods have wider applications to the general problem of deformation.

Early specification of limb muscle precursor cells by the homeobox gene Lbx1h

During vertebrate embryogenesis, myogenic precursor cells of limb muscles delaminate from the ventro-lateral edge of the somitic dermomyotome and migrate to the limb buds, where they congregate into dorsal and ventral muscle masses. It has been proposed that the surrounding connective tissue controls muscle pattern formation in limbs. Regulatory molecules such as receptor tyrosine kinases like c-Met ( ref. 6) and those encoded by homeobox-containing genes, including c-Met (ref. 6), Tbx1 (ref. 7), Mox2 (ref. 8), Six1 and Six2 (ref. 9), Pitx2, Pax3 (refs 10,11) and Lbx1h (refs 12,13), are expressed in migrating limb precursor cells. The role of these genes in the patterning of limb muscles is unknown, although mutation of Pax3 or Met causes disruption of limb muscle development at an initial step, disturbing the epithelial-to-mesenchymal transition of the somitic epithelium. No limb muscle cells form in these mutants, and the early loss of myogenic precursor cells prevented an analysis of later functions of these genes during limb muscle development. Based on quail-chick chimaera studies, it was assumed that a cell-autonomous contribution of myogenic cells to the formation of individual limb muscles is negligible, and that an instructive role of limb mesenchyme is critical in this process. Here we show that Lbx1h determines migratory routes of muscle precursor cells in a cell-autonomous manner, thereby leading to the formation of distinct limb muscle patterns. Inactivation of Lbx1h, which is specifically expressed in migrating muscle precursor cells, led to a lack of extensor muscles in forelimbs and an absence of muscles in hindlimbs. The defect was caused by the failure of all muscle precursor cells of hindlimbs and of precursor cells of extensor muscles of forelimbs to migrate to their corresponding muscle anlagen. Our results demonstrate that Lbx1h is a key regulator of muscle precursor cell migration and is required for the acquisition of dorsal identities of forelimb muscles.

Virtual reality and anthropology

Since the discovery of the Tyrolean Iceman in 1991 advanced imaging and post processing techniques were successfully applied in anthropology. Specific techniques include spiral computed tomography and 3-dimensional reconstructions including stereolithographic and fused deposition modeling of volume data sets. The Iceman's skull was the first to be reproduced using stereolithography, before this method was successfully applied in preoperative planning. With the advent of high-end graphics workstations and biomedical image processing software packages, 3-dimensional reconstructions were established as a routine tool for analyzing volume data sets. These techniques opened totally new insights in the field of physical anthropology. Computed tomography became the ideal research tool to access the internal structures of various precious fossils without damaging or even touching them. Many of the most precious specimens from the species Autralopithecus (1.8-3.5 Myears), Homo heidelbergensis (200-600 kyears) or Homo neanderthalensis (40-100 kyears) were scanned during the last 5 years. Often the fossils are filled with a stone matrix or other materials. During the postprocessing routines highly advanced algorithms were used to remove virtually these incrustations. Thus it was possible to visualize the morphological structures that lie beneath the matrix. Some specimen were partially destroyed, so the missing parts were reconstructed on computer screen in order to get estimations of the brain volume and endocranial morphology, both major fields of interest in physical anthropology. Moreover the computerized form of the data allows new descriptions of morphologic structures by the means of 'geometric morphometrics'. Some of the results may change aspects and interpretations in human evolution. The introduction of new imaging and post processing techniques created a new field of research: Virtual Anthropology.

Chimeric virus-like particles of the human papillomavirus type 16 (HPV 16) as a prophylactic and therapeutic vaccine

Infection by certain human papillomaviruses (HPV), most notably HPV types 16 and 18, is the major risk factor for cervical cancer. Worldwide, this disease represents the second most frequent malignant tumor in women; thus, there is urgent need for efficient therapy and prevention. The natural history of cervical cancer and its precursors (cervical intraepithelial neoplasias), as well as animal experiments, strongly suggest that the immune system controls both the primary infection (by neutralizing antibodies directed against the major structural protein L1) and the progression of the disease (via cytotoxic T cells specific for the viral oncoproteins expressed in transformed cells, e.g., E7). By the expression of an HPV 16 L1E7 fusion protein, we have generated chimeric virus-like particles (CVLP). Immunization of mice with CVLPs induces neutralizing antibodies directed against L1 virus-like particles (devoid of the E7 portion) and E7-specific T cells as measured in vitro. Vaccinated animals are protected against tumor growth following inoculation of syngeneic HPV 16-transformed cells. In addition, we observed a therapeutic effect of vaccination on pre-existing tumors. This data allowed us to conclude that CVLPs are suitable for prevention and therapy of HPV infection. A vaccine based on HPV 16 L1E7 CVLPs is currently under development.

Low-dimensional dynamics in sensory biology 2: facial cold receptors of the rat

We report the results of a search for evidence of unstable periodic orbits in the sensory afferents of the facial cold receptors of the rat. Cold receptors are unique in that they exhibit a diversity of action potential firing patterns as well as pronounced transients in firing rate following rapid temperature changes. These characteristics are the result of an internal oscillator operating at the level of the membrane potential. If such oscillators have three or more degree of freedom, and at least one of which also exhibits a nonlinearity, they are potentially capable of complex activity. By detecting the existence of unstable periodic orbits, we demonstrate low-dimensional dynamical behavior whose characteristics depend on the temperature range, impulse pattern, and temperature transients.

Immune response to human papillomavirus 16 L1E7 chimeric virus-like particles: induction of cytotoxic T cells and specific tumor protection

Expression of human papillomavirus type 16 (HPV 16) fusion proteins LI deltaCE7(1-55) and LI deltaCE7(1-60) (carboxy-terminal deletion of LI replaced by 55 or 60 amino-terminal amino acids of E7) leads to formation of chimeric papillomavirus-like particles (CVLPs). After "infection" of cells by CVLPs, the chimeric proteins can be detected in the cytosol and the endoplasmic reticulum (ER), suggesting that they are intracellularly processed via the MHC class I pathway and, therefore, able to activate cytotoxic T lymphocytes (CTLs). To investigate the cytotoxic immune response against HPV 16 LI deltaCE7(1-60) and LI deltaCE7(1-55) CVLPs, we immunized C57Bl/6 mice with various CVLP doses without adjuvant. Two weeks after immunization, spleen cells were prepared and stimulated in vitro using HPV 16 E7-expressing transfectants of the tumor cell line RMA. In 51Cr-release cytotoxicity assays, spleen cells of mice vaccinated with LI deltaCE7(1-60) CVLPs specifically lysed the RMA-E7 transfectants as well as RMA cells loaded with the peptide E7(49-57), which represents an H2-Db-restricted CTL epitope. This demonstrates that CVLPs induce an E7-specific CTL response in mice in the absence of an adjuvant. Furthermore, immunization with CVLPs prevented outgrowth of E7-expressing tumor cells even if inoculation of cells was performed 2 weeks before vaccination. We conclude from our data that CVLPs show promise for therapy of HPV-associated lesions.

Sequential cycles of high-dose chemotherapy with dose escalation of carboplatin with or without paclitaxel supported by G-CSF mobilized peripheral blood progenitor cells: a phase I/II study in advanced ovarian cancer

To assess high-dose carboplatin chemotherapy with or without paclitaxel with filgrastim mobilized peripheral blood progenitor cell (PBPC) support in a phase I/II study, a total of 21 patients with mostly chemonaive disease received four cycles of high-dose chemotherapy. Cycle 1 (cyclophosphamide, 6 g/m2) was followed by two cycles of carboplatin (1600 mg/m2 or 1800 mg/m2). Cycle 4 consisted of carboplatin (1600 mg/m2), etoposide (1600 mg/m2), and melphalan (140 mg/m2). Further chemotherapy intensification was achieved by adding paclitaxel (175 mg/m2) to all cycles with a fixed carboplatin dose (1600 mg/m2). Ototoxicity was dose-limiting for escalation of sequential cycles of carboplatin. Grade 2 and grade 3 ototoxicity, hearing loss not requiring a hearing aid, or hearing loss correctable with a hearing aid, was observed with carboplatin at 1800 mg/m2. The maximum tolerated dose (MTD) of sequential carboplatin, therefore, was identified in this study as 1600 mg/m2. After cycles 1, 2, 3 and 4 the median duration of leukopenia (<1.0x10(9)/l) was 7, 4, 4 and 6 days. Severe grade 3 and 4 infections were seen in only 7% of cycles. Of the 21 patients evaluable for disease response, 57% had complete remissions and 43% experienced partial remissions resulting in an overall response rate of 100%. The median progression-free survival is 25 (15-36) months, the median overall survival 36.5 (15-38) months. Most patients were suboptimally debulked or had bulky residual disease at the start of chemotherapy. Sequential high-dose chemotherapy to a maximum dose of 1600 mg/m2 carboplatin is effective and feasible. A randomized, prospective trial comparing sequential high-dose chemotherapy with optimal standard chemotherapy is now warranted.

[A method for reducing the risk of infection in newborn and premature infants with stomas]

Prematures and neonates with stomas have a high risk of developing sepsis by bacterial translocation, particularly when combined with parenteral nutrition. We studied a group of 35 newborns where split ileo- or jejunostomas were implanted in their first week of life. To prevent the development of a non-used distal bowel and a short bowel syndrome, the proximal bower content was transferred into the aboral stoma via the new continuous extracorporal stool transport (CEST) technique a few days after surgery. By using CEST the sepsis rate was reduced from 9 (without CEST) to only 0.8 cases of sepsis in 1000 days.

(S)-4C3HPG reduces infarct size after focal cerebral ischemia

This study investigated whether the metabotropic glutamate receptor ligand (S)-4C3HPG can reduce brain damage after focal ischemia in rats. Application of 1 micromol of (S)-4C3HPG (intracerebroventricularly) 5 min after occlusion of the middle cerebral artery significantly reduced the infarct size by 72.3% of the saline control.

Smoking as a risk factor for end-stage renal failure in men with primary renal disease

BACKGROUND

It is not known whether smoking increases the risk of end-stage renal failure (ESRF) in patients with primary renal disease.

METHODS

We performed a retrospective multicenter case-control study including 582 patients from nine centers in Germany, Italy and Austria. The diseases investigated were IgA glomerulonephritis (IgA-GN) as a model of inflammatory renal disease and autosomal dominant polycystic kidney disease (ADPKD) as a model of non-inflammatory renal disease. Cases were patients who had progressed to ESRF and controls were patients who were not in ESRF, that is, whose serum-creatinine failed to progress to >3 mg/dl during the observation period and who did not require renal replacement therapy. Matching for renal disease (IgA-GN, ADPKD), gender, age at renal death and region of residence resulted in 102 individually matched pairs (IgA-GN N = 54, ADPKD N = 48). Multiple conditional logistic regression was used to estimate adjusted odds ratios for independent tobacco effects.

RESULTS

In men (matched pairs: IgA-GN N = 44, ADPKD N = 28), a significant dose-dependent increase of the risk to progress to ESRF was found (non-adjusted). The baseline risk was defined as <5 pack-years (PY): (i) 5 to 15 PY, odds ratio 3.5 (95% CI 1.3 to 9.6), P = 0.017; (ii) >15 PY = 5.8 (2.0 to 17), P = 0.001. Systolic blood pressure, ACE inhibitor treatment and age at diagnosis emerged as potential confounders. After adjustment, the risk for ESRF in men with >5 PY was highly increased for patients without ACE inhibitor treatment [10.1 (2.3 to 45), P = 0.002] but not with ACE inhibitor treatment [1.4 (0.3 to 7.1), P = 0.65].

CONCLUSION

Smoking increases the risk of ESRF in men with inflammatory and non-inflammatory renal disease.

Pax-3 is necessary but not sufficient for lbx1 expression in myogenic precursor cells of the limb

In vertebrates all skeletal muscles of trunk and limbs are derived from condensations of the paraxial mesoderm, the somites. Limb muscle precursor cells migrate during embryogenesis from somites to limb buds where migration stops and differentiation occurs. We have characterized lbx1 homeobox genes in chicken and mice and found them to be expressed in migrating limb muscle precursor cells in both species. Analysis of splotch mutant mice showed that lbx1 and c-met are differently affected by the lack of Pax-3. Limb buds of splotch (Pax-3 mutant) mice were devoid of lbx1 transcripts, while expression of c-met was still detectable at a low level. The presence of c-met-positive cells in splotch mice entering the limbs indicates that migration of cells from somites to limbs is not entirely dependent on Pax-3. We show that induction of epithelial to mesenchymal transition of Pax-3-positive cells by SF/HGF was not sufficient to induce ectopic lbx-1 expression at the inter-limb level, while ectopic limb formation was able to activate lbx1 expression. We postulate that Pax-3 is necessary for lbx1 expression in the lateral tips of somites but additional, yet unknown signals derived from limb buds are needed to initiate lbx1 expression. The role of limb bud-derived signals involved in targeted muscle precursor cell migration, and lbx1 activation was further confirmed by analysis of explanted somite/limb bud co-cultures in collagen gels.

Lipopolysaccharide-binding protein is present in effluents of patients with Gram-negative and Gram-positive CAPD peritonitis

BACKGROUND

Bacterial peritonitis is a frequent complication during treatment of end-stage renal failure by continuous ambulatory peritoneal dialysis. Local host defence mechanisms including the secretion of proinflammatory cytokines by peritoneal macrophages are of particular importance in the pathogenesis of infectious complications. LPS-binding protein (LBP) and soluble CD14 (sCD14) are serum factors known to regulate the endotoxin-induced cellular immune response. However, it is still unknown whether LBP and sCD14 are also present in the peritoneal effluent of CAPD patients.

METHODS

Using specific immunoassays, we examined the concentration of LBP, sCD14 and the proinflammatory cytokines TNF-alpha, IL-1beta and IL-6 in the dialysis effluents of 31 patients with CAPD-associated peritonitis. Twenty patients without peritonitis served as controls. Intraperitoneal LPS concentrations were determined using the limulus amebocyte lysate assay.

RESULTS

Bacterial lipopolysaccharide could be detected in 42% of the infected dialysis effluents. In comparison to controls (0.2 +/- 0.05 microg/ml), LBP was significantly elevated in both gram-negative/LPS-positive (1.03 +/- 0.3 microg/ml) and gram-positive infections (0.5 +/- 0.14 microg/ml) (P<0.05). No significant differences were detected concerning the intraperitoneal sCD14 levels in the three patient groups. Levels of TNF-alpha, IL-1beta and IL-6 were significantly increased in the effluents of patients with bacterial peritonitis compared to noninfected controls. Moreover the respective cytokine concentrations were significantly higher in the gram-negative/LPS-positive compared to the gram-positive bacterial infections (P<0.01).

CONCLUSION

Our data demonstrate that LBP is significantly elevated in the dialysis effluents of patients with CAPD-associated peritonitis caused by both gram-negative and gram-positive bacteria and might be used as a marker of intraperitoneal infection. Moreover, our findings support the concept that LBP enhances the effects of LPS on cytokine production by peritoneal macrophages. The function of LBP in gram-positive infection remains to be further elucidated.

[Local effects and changes in wound drainage in the free peritoneal cavity]

In a prospective randomised study 30 mongrel rabbits received two standard colon-resections. Three types of drains were tested: (latex-rubber-) Penrose-drains, rubbertube- and silicontube-drains, which were placed in the lower abdomen. As a closed drainage-system the extraperitoneal tip of the drain was placed in a closed subcutis-pocket. One of the two colon-anastomoses also was drained. The findings were recorded on the 7th postoperative day. A single mechanic alteration was found, an ulcer caused by a silicon-drain, that pushed against the abdominal wall. The other signs of mechanic irritation were microscopically unspecified inflammatory reactions to the foreign body drain. There was no ascending infection caused by the drain. All infections came from complications of the colon resections. In contrast to common opinions the drains in the lower abdomen showed no adhesions to the abdominal wall or organs. Only the entrance of the drain into the peritoneum and the cotton-gaze of Penrose-drains showed in nearly all cases adhesions. The large amount of adhesions to the anastomosis-drains came from complications of the colon-anastomoses. As a cause of material, rubber- and latex-rubber-drains showed large fibrin-clots on their surfaces. 7 days after the operation only about 20% of the drains had sufficient function. The rest was occluded by fibrin-clots in the lumen of the drain or the cotton-gaze. Over all there is no difference in changes and effects of the three different types of drains, but silicon as material showed advantages.

Lipopolysaccharide binding protein: a marker for intraperitoneal bacterial infection in patients with CAPD peritonitis

During systemic infection, the serum lipopolysaccharide binding protein (LBP) binds to the lipid A component of bacterial endotoxins and facilitates its delivery to the CD 14 receptor on the cell surface of macrophages, where proinflammatory cytokines are released. There is no knowledge to date whether LBP is also present in the effluent of patients with continuous ambulatory peritoneal dialysis (CAPD)-associated peritonitis. We investigated the dialysis effluent of 37 patients with CAPD peritonitis for immunoreactive LBP, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-1 beta and compared the findings with the cytokine levels in 20 noninfected CAPD patients. The mean +/- SEM concentrations of LBP, TNF-alpha, and IL-1 beta were significantly higher in the effluent of patients with peritonitis than in noninfected CAPD effluent. In comparison to controls (0.23 +/- 0.05 microgram/mL), LBP was 0.68 +/- 0.13 microgram/mL in the effluent of patients with CAPD-associated infectious peritonitis. For TNF-alpha, levels were 0.50 +/- 0.25 pg/mL in the control effluent versus 124.7 +/- 46.6 pg/mL in the effluent of peritonitis patients. For IL-1 beta the levels were 0.24 +/- 0.14 pg/mL in the control effluent and 71.23 +/- 17.53 pg/mL in the peritonitis patients. Our findings demonstrate that LBP is significantly elevated in the effluent of CAPD patients during an episode of CAPD-associated peritonitis and might be used as a marker of intraperitoneal bacterial infection.

Low-dimensional dynamics in sensory biology. 1: Thermally sensitive electroreceptors of the catfish

We report the results of a search for evidence of periodic unstable orbits in the electroreceptors of the catfish. The function of these receptor organs is to sense weak external electric fields. In addition, they respond to the ambient temperature and to the ionic composition of the water. These quantities are encoded by receptors that make use of an internal oscillator operating at the level of the membrane potential. If such oscillators have three or more degrees of freedom, and at least one of which also exhibits a nonlinearity, they are potentially capable of chaotic dynamics. By detecting the existence of stable and unstable periodic orbits, we demonstrate bifurcations between noisy stable and chaotic behavior using the ambient temperature as a parameter. We suggest that the technique developed herein be regarded as an additional tool for the analysis of data in sensory biology and thus can be potentially useful in studies of functional responses to external stimuli. We speculate that the appearance of unstable orbits may be indicative of a state of heightened sensory awareness by the animal.