Carbon dioxide insufflation deflects airborne particles from an open surgical wound model.

BACKGROUND: Surgical site infections remain a significant burden on healthcare systems and may benefit from new countermeasures. AIM: To assess the merits of open surgical wound CO2 insufflation via a gas diffuser to reduce airborne contamination, and to determine the distribution of CO2 in and over a wound. METHODS: An experimental approach with engineers and clinical researchers was employed to measure the gas flow pattern and motion of airborne particles in a model of an open surgical wound in a simulated theatre setting. Laser-illuminated flow visualizations were performed and the degree of protection was quantified by collecting and characterizing particles deposited in and outside the wound cavity. FINDINGS: The average number of particles entering the wound with a diameter of <5µm was reduced 1000-fold with 10L/min CO2 insufflation. Larger and heavier particles had a greater penetration potential and were reduced by a factor of 20. The degree of protection was found to be unaffected by exaggerated movements of hands in and out of the wound cavity. The steady-state CO2 concentration within the majority of the wound cavity was >95% and diminished rapidly above the wound to an atmospheric level (∼0%) at a height of 25mm. CONCLUSION: Airborne particles were deflected from entering the wound by the CO2 in the cavity akin to a protective barrier. Insufflation of CO2 may be an effective means of reducing intraoperative infection rates in open surgeries.

Influence of cytomegalovirus infection on the recovery of humoral immunity after autologous bone marrow transplantation.

Recovery of B-cell number and function was studied in 23 patients with hematological malignancies treated with high-dose chemoradiotherapy followed by autologous bone marrow transplantation (auto-BMT) in relation to the presence or absence of cytomegalovirus (CMV) infection. B cells recovered rapidly after auto-BMT and specific antibodies to herpes viruses remained nearly unchanged. Both were independent of the CMV status of the patients. However, the capacity of peripheral blood B cells to differentiate in vitro into cytoplasmic immunoglobulin (Ig)-positive cells (plasma cells) on pokeweed mitogen stimulation in the presence of normal T-cell help was significantly better in CMV-negative patients than in CMV-positive patients after auto-BMT, but was decreased in both groups. Serum Ig levels were, in contrast, higher in CMV-positive patients than in CMV-negative patients after auto-BMT.

Development of spinocerebellar afferents in the clawed toad, Xenopus laevis.

The development of spinocerebellar projections in the clawed toad, Xenopus laevis, was studied with horseradish peroxidase as an anterograde and retrograde tracer. Early in development cells of origin of spinocerebellar projections were found, contralaterally, in or close to the medial motor column. In older tadpoles ipsilaterally projecting spinal neurons were also labeled from the cerebellum. These are virtually indistinguishable from the large primary motoneurons that occupy a very similar position in the spinal cord. Most of the labeled spinal cells were found in the thoracic spinal cord; they lie halfway between the brachial and lumbar secondary motor columns. Surprisingly, no primary spinocerebellar projection arising from dorsal root spinal ganglion cells could be demonstrated in X. laevis tadpoles and adult toads. Therefore, fibers in the cerebellum that were labeled anterogradely from the spinal cord can be expected to originate exclusively from the secondary spinocerebellar tract cells. These fibers appear to cross the cerebellum in or at the border of the granular layer. The present data suggest that in X. laevis early in the development of the cerebellum a distinct secondary spinocerebellar projection is already present, originating in neurons that can be compared with the "spinal border cells" in mammals. The relative sparseness of this secondary spinocerebellar projection and the apparent absence of primary spinocerebellar afferents probably indicate that spinocerebellar pathways are only of minor importance in X. laevis. The possibility remains, however, that the expansion of the secondary spinocerebellar pathway only starts when metamorphosis has been completed.

Development of olivocerebellar fibers in the clawed toad, Xenopus laevis: a light and electron microscopical HRP study.

An anterograde tracer study was undertaken to provide a light- and electron microscopical description of climbing fiber development in the clawed toad, Xenopus laevis, ranging from premetamorphic stages to the adult state. The inferior olive was unilaterally labeled with horseradish peroxidase and the contralateral climbing fiber morphology investigated. At early stages of development, only undifferentiated fibers were observed in the rostral alar plate. At later stages, these fibers form large varicosities, which contact presumed cerebellar Purkinje cells. Finger-like protrusions arising from the Purkinje cell somata penetrate the climbing fiber varicosities and form synaptic specializations at these contact sites. In older tadpoles, a large variety of climbing fiber morphologies was found displaying a mediolateral gradient. At dorsolateral cerebellar areas long and straight climbing fibers follow the Purkinje cell primary dendrites. However, in ventromedial areas pericellular baskets or nests were found on presumed Purkinje cell somata. These pericellular nests were found throughout development but were not observed in adult animals. Both pericellular nests and real climbing fibers make synaptic contacts on spiny protrusions of the Purkinje cell's somatic or dendritic surface. In several cases, labeled as well as unlabeled climbing fiber profiles were observed on the same Purkinje cell, indicating multiple, convergent innervation. Also, divergent Purkinje cell innervation was found. In conclusion, this study shows that anuran climbing fiber development encompasses stages and processes similar to those observed in mammals. The only principal difference with climbing fiber development in mammals is the low degree of synchrony observed in anurans.

The effect of clozapine on caudate nucleus volume in schizophrenic patients previously treated with typical antipsychotics.

Typical antipsychotics have been reported to enlarge the caudate nucleus in schizophrenic patients. The atypical antipsychotic, clozapine, is associated with a decrease in caudate size in patients previously treated with typical antipsychotics. The present study investigates whether a change in caudate volume after switching from treatment with typical antipsychotics to treatment with clozapine is related to improvement in symptoms or tardive dyskinesia (TD). Twenty-six schizophrenic patients participated in this open study. Caudate nucleus volume and TD were assessed before discontinuing typical antipsychotics and after 24 weeks of treatment with clozapine. After discontinuing typical antipsychotics, symptoms were assessed in a 3 days drug-free period and subsequently once a month. Treatment with clozapine resulted in a decrease in caudate volume, improvement in symptoms and amelioration of TD. However, no difference in caudate volume changes was found between responders and non-responders to clozapine and no correlations were found between caudate volume changes and reduction of TD. In conclusion, this study replicates earlier findings that clozapine decreases caudate volume in patients previously treated with typical antipsychotics and suggests that this effect is unrelated to treatment response or to amelioration of TD.

Cellular immunity to vaccinations and herpesvirus infections after bone marrow transplantation.

The cellular immune response to herpesviruses was studied in 46 recipients of marrow grafts (23 autologous, 23 allogeneic). That study was performed in vitro by evaluating the degree of lymphocyte proliferative responses to herpes simplex virus (HSV), cytomegalovirus (CMV), and varicella zoster virus (VZV). No primary infections with any of those viruses were noted after bone marrow transplantation (BMT). The incidence of active infection in seropositive patients was significantly lower after autologous BMT than after allogeneic BMT (HSV, 2/22 vs. 11/22 patients, respectively, P = 0.007; CMV, 4/12 vs. 9/10 patients, respectively, P = 0.02; VZV, 3/23 vs. 11/23 patients, respectively, P = 0.02). After autologous BMT, the restoration of cellular immunity to the three viruses occurred at a clearly faster rate than after allogeneic BMT. That pattern may have contributed to the low incidence of active infections with those viruses after autologous BMT. Recipients of allogeneic marrow from donors with a positive lymphocyte proliferation test to HSV had a significantly increased incidence of active HSV infection post-BMT (8/9 patients) than those who received marrow from donors with a negative test (3/13 patients; P = 0.008). Acute or chronic graft-versus-host disease (GVHD) decreased the cellular immune response to the three herpes viruses, but not significantly. Our program of vaccinations with diphtheria and tetanus toxoids started in the fourth month post BMT. Chronic GVHD patients who were vaccinated had a clearly impaired cellular immune response to both toxoids as compared with those without chronic GVHD.

Blunted cortisol response to a psychosocial stressor in schizophrenia.

Schizophrenia is considered a neurodevelopmental disorder in which vulnerability to stress may be a contributing factor. Coping is an important psychological component of stress processing, and the hypothalamic-pituitary-adrenal system (HPA system) is one of the biological components of stress adaptation. Disturbances of either of these components may make schizophrenic patients more vulnerable to develop a psychosis under stressful circumstances. In this study, 10 schizophrenic men were compared with 10 healthy male controls in their response to a psychosocial stressor, consisting of a public-speaking task. Heart rate was monitored as a measure of autonomic arousal. HPA responses were assessed by measuring salivary cortisol. Coping skills were measured by using the Utrecht Coping List and the Ways of Coping Checklist. The stress of speaking in public increased the heart rate in both patients and controls; however, a significant cortisol response was found in the controls, but not in the schizophrenic patients. The patients used more passive and avoidant coping strategies than controls. The findings provide support for the notion that schizophrenic patients have an impaired ability to adapt, both psychologically and biologically, to their environment.

N-terminal cysteines essential for Golgi sorting of B-50 (GAP-43) in PC12 cells.

We have examined the subcellular distribution of the growth-associated protein B-50 (GAP-43) in pheochromocytoma (PC12) cells, using confocal microscopy. Proliferating PC12 cells contained very low levels of B-50 in the cytosol. Enhanced expression of B-50 in these cells, evoked by either nerve growth factor (NGF) treatment or transient transfection with rat B-50 cDNA, led to Golgi sorting and membrane targeting of the B-50 protein. Site directed mutagenesis of Cys3Cys4 to Ser3Gly4 in B-50 resulted in a cytosolic distribution. We conclude that Cys3, and Cys4 are essential for accumulation of B-50 both at the plasma membrane and in the Golgi apparatus of PC12 cells.

Early development of rubrospinal and cerebellorubral projections in Xenopus laevis.

In Xenopus laevis HRP was applied at the spinomedullary border at various stages of development. In these experiments labeled rubrospinal neurons were observed from stage 48 on. HRP applications to the mesencephalic tegmentum showed, from stage 49 on, retrogradely labeled neurons in the cerebellar nucleus, particularly contralaterally. These data suggest that anuran cerebellorubral projections arise early, well before the rubrospinal innervation of the spinal cord is complete.

Morphological evidence for a monosynaptic connection between cerebellar Purkinje cells and vestibulospinal tract neurons in the larval clawed toad, Xenopus laevis.

A double-labeling technique was used to trace synaptic connections between the efferent neurons of the cerebellum (Purkinje cells) and vestibulospinal tract neurons in larvae of the clawed toad, Xenopus laevis. The efferent cerebellar projection was labeled with horseradish peroxidase (HRP) while in the same preparations the brainstem neurons projecting to the spinal cord were labeled with cobaltous lysine. It was found that the distribution of the Purkinje cell terminal boutons overlaps significantly with the location of vestibulospinal neurons in the brainstem. Moreover, several close appositions were seen between Purkinje cell boutons and the dendrites and somata of these latter neurons. The close appositions seen in light microscopy were confirmed by subsequent electron microscopy. This study shows that early in development (at least well before metamorphosis) a cerebello-vestibulospinal connection exists in Xenopus laevis. This connection is likely to persist throughout metamorphosis to the adult state.

Bicuculline increases the intracellular calcium response of CA1 hippocampal neurons to synaptic stimulation.

Intracellular calcium levels were measured by ratio imaging of Fura-2-injected CA1 pyramidal neurons during repetitive electrical stimulation of the Schaffer collaterals in rat hippocampal slices. Baseline intracellular calcium levels of 102 nM increased to 190 nM during a 3-s stimulus train of 5 Hz. Bicuculline (20 microM) significantly enhanced this stimulus-dependent rise in intracellular calcium, while the baseline calcium levels remained unchanged. Concomitantly performed extra- and intracellular electrophysiological recordings indicate that the increased calcium response in the presence of bicuculline is linked to a prolongation of the excitatory postsynaptic potential and the induction of multiple action potentials. The bicuculline-induced increased calcium response could have long-term implications for cell function and eventually lead to cell degeneration.

Observations on the development of cerebellar afferents in Xenopus laevis.

The development of cerebellar afferents has been studied in the clawed toad, Xenopus laevis, from stage 46 to 64, with the horseradish peroxidase retrograde tracer technique. Already in stage 48 tadpoles, i.e. before the formation of the limbs, a distinct set of cerebellar afferents was found. Vestibulocerebellar (mainly arising bilaterally in the nucleus vestibularis caudalis) and contralateral olivo-cerebellar projections dominate. Secondary trigeminocerebellar (from the descending nucleus of the trigeminal nerve) and reticulocerebellar connections were also found. At stage 50, spinocerebellar projections appear originating from cervical and lower thoracic/upper lumbar levels. The cells of origin of the spinocerebellar projection can be roughly divided in two neuronal types: ipsilaterally projecting large cells, which show a marked resemblance to primary motoneurones ('spinal border cells') and smaller contralaterally projecting neurons. Primary spinocerebellar projections from spinal ganglion cells could not be demonstrated. At stage 50, a possible anuran homologue of the mammalian nucleus prepositus hypoglossi was found to project to the cerebellum. In only one of the experiments labeled neurons were found in the contralateral mesencephalic tegmentum. At none of the studied stages a raphecerebellar projection could be demonstrated. It appears that already early in cerebellar development, before the formation of the limbs, most of the cerebellar afferents as found in adult Xenopus laevis are present.

Middle cerebral artery flow velocity during coronary surgery; influence of clinical variables.

The flow velocity in the middle cerebral artery was measured continuously with a noninvasive transcranial Doppler in 18 patients during coronary artery surgery. Neurolept anesthesia and alpha-static acid-base management were employed. The flow velocity data were expressed as a percent of the awake level. During intubation, there was a transient flow velocity increase, which was related to a concomitant increase in mean arterial pressure (r = 0.67, p less than 0.01). Prior to cardiopulmonary bypass, flow velocity had decreased to 52.4% +/- 3.0% (mean +/- SEM). At the onset of cardiopulmonary bypass, flow velocity values were transiently doubled. Flow velocity then reached a stable level of 63% to 65% during hypothermia (25 degrees C to 30 degrees C). The increase from 52.4% to 63% to 65% was related to the reduction in hematocrit (r = -0.62, p less than 0.02). With rewarming, flow velocity increased to 101% +/- 5.2%. Flow velocity was found to correlate with temperature during cardiopulmonary bypass (median rs = 0.84, range 0.61 to 0.99, p less than 0.0001). No positive correlation was found between mean arterial pressure (MAP) and flow velocity during cardiopulmonary bypass. Although no direct metabolic measurements were performed, it is concluded that these findings are compatible with a maintained cerebral blood flow/metabolic coupling during cardiopulmonary bypass.

Brain morphology in antipsychotic-naïve schizophrenia: a study of multiple brain structures.

BACKGROUND: Although brain volume changes are found in schizophrenia, only a limited number of structural magnetic resonance imaging studies have exclusively examined antipsychotic-naïve patients. AIMS: To comprehensively investigate multiple brain structures in a single sample of patients who were antipsychotic-naïve. METHOD: Twenty antipsychotic-naïve patients with first-episode schizophrenia and 20 healthy comparison subjects were included. Intracranial, total brain, frontal lobe, grey and white matter, cerebellar, hippocampal, parahippocampal, thalamic, caudate nucleus and lateral and third ventricular volumes were measured. Repeated-measures analyses of (co)variance were conducted with intracranial volume as covariate. RESULTS: Third ventricle volume enlargement was found in patients compared with the healthy subjects. No differences were found in other brain regions. CONCLUSIONS: These findings suggest that some brain abnormalities are present in the early stages of schizophrenia. Moreover, it suggests that brain abnormalities reported in patients with chronic schizophrenia develop in a later stage of the disease and/or are medication induced.

Simple three-dimensional imaging of HRP-labelled neurons with the aid of an image processor.

A method is described for visualizing the three-dimensional structure of horseradish peroxidase-labelled neurons in the central nervous system of Xenopus laevis tadpoles. The reconstruction is simple, and performed on a commercially available image processing system. Minimal operational skill is required for using this method. Also, various improvements were made where user's simplicity (user-friendliness), speed and required computer memory are concerned. In addition, the excellent properties of the IBAS II system, such as image filtering and image editing functions are fully available, offering a fast, clean and complete final image reconstruction.

Image processing and analysis program for measurement of bone density changes in reference and follow-up standardized extraoral oblique lateral cephalometric radiographs of the mandible.

OBJECTIVES: The aim of this study was to develop an image processing and analysis program for peri-implant bone density measurements of the mandible using extraoral radiographs, which includes a correction for the variable projection of the soft tissues of the face. METHODS: The measurement procedure is based on pairs of reference and follow-up extraoral oblique lateral cephalometric radiographs (OLCRs) of patients with endosseous implants in the anterior part of the atrophic edentulous mandible. The procedure consists of image acquisition, correction for radiographic variation using an aluminium wedge (i.e. film exposure and development) and transformation of the grey values into aluminium-equivalent values. After correction for variation in the projection of the soft tissues of the face using internal calibration fields, the actual peri-implant bone density measurements are performed. RESULTS: The soft tissue projection correction significantly reduces the variation between radiographs owing to the position of the soft tissues. CONCLUSIONS: It is concluded that the described image processing and analysis program, in combination with extraorally made OLCRs, is a valuable technique for measurement of peri-implant bone density changes of the mandible. With minor adaptations, the program can be used for other semi-edentulous patients.

HLA-DR positive T lymphocytes in blood and synovial fluid in rheumatoid arthritis.

HLA-DR expression was found on 6.7 +/- 0.7% of blood T lymphocytes from 34 patients with rheumatoid arthritis (RA) and 2.6 +/- 0.3% of T cells from normals. In synovial fluid (SF) of RA patients high percentages were found (56 +/- 3%, n = 18); the SF T lymphocytes showed an acid alpha-naphthyl acetate esterase pattern and cell morphology compatible with activated T lymphocytes. The helper function for pokeweed mitogen induced B cell differentiation was higher in blood T lymphocytes from RA patients than from normal controls; in SF T lymphocytes helper function could not be established. These differences between blood and SF T lymphocytes may represent differences in recirculating and homing properties of T cells in these compartments.

Monotypic immunoglobulin E plasma cells in an allogeneic bone marrow transplant recipient.

A patient with acute lymphoblastic leukaemia in first remission received a bone marrow transplant from his HLA-identical brother. The patient had a remote history of asthma and the bone marrow donor had allergic asthma. The patient developed acute graft-versus-host disease and died 2 months after transplantation. At autopsy there were high numbers of plasma cells in lymphoid tissues. The majority of this cell population was of polytypic IgG, IgM or IgA origin, but there was a significant contribution by monotypic IgE-lambda-containing cells, varying from 10% in the appendix to 35% in lymph node. The serum IgE level in the patient was less than 0.5 IU/ml before transplantation, and 8.5 IU/ml 1 month thereafter. In the donor the value was about 400 IU/ml. In the donor only, specific IgE antibodies to various allergens were detectable. The bone marrow of the donor contained 0.4% plasma cells, of which 36% were IgE positive (chi/lambda ratio 1/11). These findings are compatible with literature data on elevations in serum IgE level following bone marrow transplantation. We suggest that the IgE-lambda plasma cell population is of donor origin.

Spontaneous IgA synthesis by blood mononuclear cells in alcoholic liver disease.

Changes in the concentration and composition of serum immunoglobulin A (IgA) and deposits of IgA in tissues are well-known characteristics of alcoholic liver disease. We investigated whether these changes also accompany IgA synthesis by peripheral blood mononuclear cells (MNC), by counting immunoglobulin-producing cells using a solid-phase enzymatic 'spot' test, and by analysis of immunoglobulin content in lysed cells with culture supernatant using conventional enzymatic methods. Patients with alcoholic liver disease exhibited a significantly higher number of spontaneously IgA-producing cells than did normal healthy controls (1.7 X 10(6) cells/blood and 0.5 X 10(6) cells/blood, respectively, P less than 0.01). The IgA content of MNC directly after isolation was also higher (38 and 13 ng/10(6) MNC, respectively, P less than 0.01), as was the IgA production during an unstimulated 6-day culture period (520 and 95 ng/10(6) MNC put into culture, respectively, P less than 0.001). The spontaneously IgA-producing cells assessed directly after isolation of mononuclear cells correlated with the IgA production during an unstimulated culture (P less than 0.01). We conclude that in alcoholic liver disease, B lymphocytes circulate which may have been activated in vivo.