Cancer History Avoids the Increase of Senescence Markers in Peripheral Cells of Amnestic Mild Cognitive Impaired Patients

Epidemiological studies show that having a history of cancer protects from the development of Alzheimer's Disease (AD), and vice versa, AD protects from cancer. The mechanism of this mutual protection is unknown. We have reported that the peripheral blood mononuclear cells (PBMC) of amnestic cognitive impairment (aMCI) and Alzheimer's Disease (AD) patients have increased susceptibility to oxidative cell death compared to control subjects, and from the opposite standpoint a cancer history is associated with increased resistance to oxidative stress cell death in PBMCs, even in those subjects who have cancer history and aMCI (Ca + aMCI). Cellular senescence is a regulator of susceptibility to cell death and has been related to the pathophysiology of AD and cancer. Recently, we showed that cellular senescence markers can be tracked in PBMCs of aMCI patients, so we here investigated whether these senescence markers are dependent on having a history of cancer. Senescence-associated βeta-galactosidase (SA-β-Gal) activity, G0-G1 phase cell-cycle arrest, p16 and p53 were analyzed by flow cytometry; phosphorylated H2A histone family member X (γH2AX) by immunofluorescence; IL-6 and IL-8 mRNA by qPCR; and plasmatic levels by ELISA. Senescence markers that were elevated in PBMCs of aMCI patients, such as SA-β-Gal, Go-G1 arrested cells, IL-6 and IL-8 mRNA expression, and IL-8 plasmatic levels, were decreased in PBMCs of Ca + aMCI patients to levels similar to those of controls or of cancer survivors without cognitive impairment, suggesting that cancer in the past leaves a fingerprint that can be peripherally traceable in PBMC samples. These results support the hypothesis that the senescence process might be involved in the inverse association between cancer and AD.

Long-term potentiation and spatial memory training stimulate the hippocampal expression of RyR2 calcium release channels

Introduction: Neuronal Ca²⁺ signals generated through the activation of Ca²⁺-induced Ca²⁺ release in response to activity-generated Ca²⁺ influx play a significant role in hippocampal synaptic plasticity, spatial learning, and memory. We and others have previously reported that diverse stimulation protocols, or different memory-inducing procedures, enhance the expression of endoplasmic reticulum-resident Ca²⁺ release channels in rat primary hippocampal neuronal cells or hippocampal tissue. Methods and Results: Here, we report that induction of long-term potentiation (LTP) by Theta burst stimulation protocols of the CA3-CA1 hippocampal synapse increased the mRNA and protein levels of type-2 Ryanodine Receptor (RyR2) Ca²⁺ release channels in rat hippocampal slices. Suppression of RyR channel activity (1 h preincubation with 20 μM ryanodine) abolished both LTP induction and the enhanced expression of these channels; it also promoted an increase in the surface expression of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluR1 and GluR2 and caused a moderate but significant reduction of dendritic spine density. In addition, training rats in the Morris water maze induced memory consolidation, which lasted for several days after the end of the training period, accompanied by an increase in the mRNA levels and the protein content of the RyR2 channel isoform. Discussion: We confirm in this work that LTP induction by TBS protocols requires functional RyR channels. We propose that the increments in the protein content of RyR2 Ca²⁺ release channels, induced by LTP or spatial memory training, play a significant role in hippocampal synaptic plasticity and spatial memory consolidation.

Alzheimer's Disease-Like Pathology Triggered by Porphyromonas gingivalis in Wild Type Rats Is Serotype Dependent

Periodontal disease is a disease of tooth-supporting tissues. It is a chronic disease with inflammatory nature and infectious etiology produced by a dysbiotic subgingival microbiota that colonizes the gingivodental sulcus. Among several periodontal bacteria, Porphyromonas gingivalis (P. gingivalis) highlights as a keystone pathogen. Previous reports have implied that chronic inflammatory response and measurable bone resorption are observed in young mice, even after a short period of periodontal infection with P. gingivalis, which has been considered as a suitable model of experimental periodontitis. Also, encapsulated P. gingivalis strains are more virulent than capsular-defective mutants, causing an increased immune response, augmented osteoclastic activity, and accrued alveolar bone resorption in these rodent experimental models of periodontitis. Recently, P. gingivalis has been associated with Alzheimer’s disease (AD) pathogenesis, either by worsening brain pathology in AD-transgenic mice or by inducing memory impairment and age-dependent neuroinflammation middle-aged wild type animals. We hypothesized here that the more virulent encapsulated P. gingivalis strains could trigger the appearance of brain AD-markers, neuroinflammation, and cognitive decline even in young rats subjected to a short periodontal infection exposure, due to their higher capacity of activating brain inflammatory responses. To test this hypothesis, we periodontally inoculated 4-week-old male Sprague-Dawley rats with K1, K2, or K4 P. gingivalis serotypes and the K1-isogenic non-encapsulated mutant (GPA), used as a control. 45-days after periodontal inoculations with P. gingivalis serotypes, rat´s spatial memory was evaluated for six consecutive days in the Oasis maze task. Following functional testing, the animals were sacrificed, and various tissues were removed to analyze alveolar bone resorption, cytokine production, and detect AD-specific biomarkers. Strikingly, only K1 or K2 P. gingivalis-infected rats displayed memory deficits, increased alveolar bone resorption, pro-inflammatory cytokine production, changes in astrocytic morphology, increased Aβ1-42 levels, and Tau hyperphosphorylation in the hippocampus. None of these effects were observed in rats infected with the non-encapsulated bacterial strains. Based on these results, we propose that the bacterial virulence factors constituted by capsular polysaccharides play a central role in activating innate immunity and inflammation in the AD-like pathology triggered by P. gingivalis in young rats subjected to an acute experimental infection episode.

Differential navigational strategies during spatial learning in a new modified version of the Oasis maze

During spatial navigation, some typical parameters of learning have been observed, such as latency or path length. However, these parameters are sensitive to patterns of navigation and orientation that are not easily measurable. In the present study, we used a modified version of the Oasis maze and evaluated different parameters of learning, navigation, and orientation in different animal groups. Through a PCA (Principal component analysis) we found different factors such as learning, navigation, speediness, anxiety, orientation, path variability, and turning behavior. Each factor gathers different groups of behavioral variables. ANOVA analysis of those factors demonstrates that some of them are more strongly modulated by trial progression, while others by animal group differences, indicating that each group of variables is better reflecting one of these dimensions. To understand the nature of these navigation differences, we studied orientation strategies between animal conditions and across trials. We found that the main navigational strategy used by the animals consist of locating the target and directing their behaviors towards this area. When testing how this strategy changed after cognitive impairment or enhancement, we found that AβOs treated animals (Amyloid β Oligomers, Alzheimer animal model) have strong orientation difficulties at locating the target at longer distances. While animals with learning enhancement (exercised rat) do not show changes in orientation behaviors. These analyses highlight that experimental manipulations affect learning, but also induced changes in the navigational strategies. We concluded that both dimensions can explain the differences observed in typical learning variables, such as latency or path length, motivating the development of new tools that asses this two-dimension as a separate but, interacting phenomenon.

Serotype b of Aggregatibacter actinomycetemcomitans triggers pro-inflammatory responses and amyloid beta secretion in hippocampal cells: a novel link between periodontitis and Alzheimer´s disease?

Introduction: Previous reports have proposed that Periodontal disease (PDis) predisposes to Alzheimer's disease (AD), both highly prevalent pathologies among the elderly. The bacteria Aggregatibacter actinomycetemcomitans (Aa), associated with the most aggressive forms of PDis, are classified in different serotypes with distinct virulence according to the antigenicity of their lipopolysaccharide (LPS). Methods: Here, we determined the effects of purified LPS, from serotypes a, b or c of Aa, on primary cultures of microglia or mixed hippocampal cells. Results: We found that both culture types exhibited higher levels of inflammatory cytokines (IL-1β, IL-6 and TNFα) when treated with serotype b-LPS, compared with controls, as quantified by qPCR and/or ELISA. Also, cultures treated with serotype a-LPS displayed increased mRNA levels of the modulatory cytokines IL-4 and IL-10. Mixed hippocampal cultures treated with serotype b-LPS exhibited severe neuronal morphological changes and displayed increased levels of secreted Aβ_1-42 peptide. These results indicate that LPS from different Aa serotypes triggers discriminatory immune responses, which differentially affect primary hippocampal cells. Conclusion: Altogether, our results show that treatment with serotype b-LPS triggers the secretion of proinflammatory cytokines by microglia, induces neurite shrinking, and increases the extracellular Aβ1-42 levels, all features strongly associated with the etiology of AD.

N-Acetylcysteine Prevents the Spatial Memory Deficits and the Redox-Dependent RyR2 Decrease Displayed by an Alzheimer's Disease Rat Model

We have previously reported that primary hippocampal neurons exposed to synaptotoxic amyloid beta oligomers (AβOs), which are likely causative agents of Alzheimer’s disease (AD), exhibit abnormal Ca²⁺ signals, mitochondrial dysfunction and defective structural plasticity. Additionally, AβOs-exposed neurons exhibit a decrease in the protein content of type-2 ryanodine receptor (RyR2) Ca²⁺ channels, which exert critical roles in hippocampal synaptic plasticity and spatial memory processes. The antioxidant N-acetylcysteine (NAC) prevents these deleterious effects of AβOs in vitro. The main contribution of the present work is to show that AβOs injections directly into the hippocampus, by engaging oxidation-mediated reversible pathways significantly decreased RyR2 protein content but increased single RyR2 channel activation by Ca²⁺ and caused considerable spatial memory deficits. AβOs injections into the CA3 hippocampal region impaired rat performance in the Oasis maze spatial memory task, decreased hippocampal glutathione levels and overall content of plasticity-related proteins (c-Fos, Arc, and RyR2) and increased ERK1/2 phosphorylation. In contrast, in hippocampus-derived mitochondria-associated membranes (MAM) AβOs injections increased RyR2 levels. Rats fed with NAC for 3-weeks prior to AβOs injections displayed comparable redox potential, RyR2 and Arc protein contents, similar ERK1/2 phosphorylation and RyR2 single channel activation by Ca²⁺ as saline-injected (control) rats. NAC-fed rats subsequently injected with AβOs displayed the same behavior in the spatial memory task as control rats. Based on the present in vivo results, we propose that redox-sensitive neuronal RyR2 channels partake in the mechanism underlying AβOs-induced memory disruption in rodents.

Triclosan Impairs Hippocampal Synaptic Plasticity and Spatial Memory in Male Rats

Triclosan, a widely used industrial and household agent, is present as an antiseptic ingredient in numerous products of everyday use, such as toothpaste, cosmetics, kitchenware, and toys. Previous studies have shown that human brain and animal tissues contain triclosan, which has been found also as a contaminant of water and soil. Triclosan disrupts heart and skeletal muscle Ca2+ signaling, damages liver function, alters gut microbiota, causes colonic inflammation, and promotes apoptosis in cultured neocortical neurons and neural stem cells. Information, however, on the possible effects of triclosan on the function of the hippocampus, a key brain region for spatial learning and memory, is lacking. Here, we report that triclosan addition at low concentrations to hippocampal slices from male rats inhibited long-term potentiation but did not affect basal synaptic transmission or paired-pulse facilitation and modified the content or phosphorylation levels of synaptic plasticity-related proteins. Additionally, incubation of primary hippocampal cultures with triclosan prevented both the dendritic spine remodeling induced by brain-derived neurotrophic factor and the emergence of spontaneous oscillatory Ca2+ signals. Furthermore, intra-hippocampal injection of triclosan significantly disrupted rat navigation in the Oasis maze spatial memory task, an indication that triclosan impairs hippocampus-dependent spatial memory performance. Based on these combined results, we conclude that triclosan exerts highly damaging effects on hippocampal neuronal function in vitro and impairs spatial memory processes in vivo.

Contextual Fear Memory Formation and Destabilization Induce Hippocampal RyR2 Calcium Channel Upregulation

Hippocampus-dependent spatial and aversive memory processes entail Ca2+ signals generated by ryanodine receptor (RyR) Ca2+ channels residing in the endoplasmic reticulum membrane. Rodents exposed to different spatial memory tasks exhibit significant hippocampal RyR upregulation. Contextual fear conditioning generates robust hippocampal memories through an associative learning process, but the effects of contextual fear memory acquisition, consolidation, or extinction on hippocampal RyR protein levels remain unreported. Accordingly, here we investigated if exposure of male rats to contextual fear protocols, or subsequent exposure to memory destabilization protocols, modified the hippocampal content of type-2 RyR (RyR2) channels, the predominant hippocampal RyR isoforms that hold key roles in synaptic plasticity and spatial memory processes. We found that contextual memory retention caused a transient increase in hippocampal RyR2 protein levels, determined 5 h after exposure to the conditioning protocol; this increase vanished 29 h after training. Context reexposure 24 h after training, for 3, 15, or 30 min without the aversive stimulus, decreased fear memory and increased RyR2 protein levels, determined 5 h after reexposure. We propose that both fear consolidation and extinction memories induce RyR2 protein upregulation in order to generate the intracellular Ca2+ signals required for these distinct memory processes.

Performance prediction of industrial centrifuges using scale-down models

Computational fluid dynamics was used to model the high flow forces found in the feed zone of a multichamber-bowl centrifuge and reproduce these in a small, high-speed rotating disc device. Linking the device to scale-down centrifugation, permitted good estimation of the performance of various continuous-flow centrifuges (disc stack, multichamber bowl, CARR Powerfuge) for shear-sensitive protein precipitates. Critically, the ultra scale-down centrifugation process proved to be a much more accurate predictor of production multichamber-bowl performance than was the pilot centrifuge.

Scale-down of continuous filtration for rapid bioprocess design: Recovery and dewatering of protein precipitate suspensions

The early specification of bioprocesses often has to be achieved with small (tens of millilitres) quantities of process material. If extensive process discovery is to be avoided at pilot or industrial scale, it is necessary that scale-down methods be created that not only examine the conditions of process stages but also allows production of realistic output streams (i.e., streams truly representative of the large scale). These output streams can then be used in the development of subsequent purification operations. The traditional approach to predicting filtration operations is via a bench-scale pressure filter using constant pressure tests to examine the effect of pressure on the filtrate flux rate and filter cake dewatering. Interpretation of the results into cake resistance at unit applied pressure (alpha) and compressibility (n) is used to predict the pressure profile required to maintain the filtrate flux rate at a constant predetermined value. This article reports on the operation of a continuous mode laboratory filter in such a way as to prepare filter cakes and filtrate similar to what may be achieved at the industrial scale. Analysis of the filtration rate profile indicated the filter cake to have changing properties (compressibility) with time. Using the insight gained from the new scale-down methodology gave predictions of the flux profile in a pilot-scale candle filter superior to those obtained from the traditional batch filter used for laboratory development.

Laboratory scaledown of protein purification processes involving fractional precipitation and centrifugal recovery

The ability to predict the performance of large-scale processes is central to the rapid development of successful operations at the pilot and industrial scale. In this article, we examine the operation, at laboratory scale, of precipitation reactors and centrifuges for protein precipitate recovery and dewatering and how they might best mimic large-scale reactors and centrifuges, in this case, a pilot-scale batch stirred-tank reactor and a multichamber-bowl centrifuge. Novel approaches to bench-top centrifuge operation are provided, in particular with a view to delivery of material for subsequent high-resolution purification, which would be obtained at full pilot scale. Results are presented in terms of properties of the protein precipitates, the fraction of solids recovered, and the extent of dewatering achieved. Good agreement was obtained at bench scale (a 1000-fold scale down factor) for all of these parameters for pilot-scale, batch-feed operation. In addition, the methodology developed allows identification of the extent of break-up that occurs in continuous-feed centrifuges when processing shear-sensitive materials such as the protein precipitates studied here.

Protective role of vagal afferents in experimentally-induced colitis in rats

The aim of this study was to evaluate the regulatory role of vagal afferents in the development of colonic inflammation induced by trinitrobenzenesulfonic acid (TNBS) in rats. Groups of Wistar rats were treated with capsaicin or its vehicle applied perivagally (sham treatment). Colonic transit time was evaluated, and, two days later, one half of the animals received an intracolonic instillation of TNBS/ethanol (40 mg/kg), and the other received saline. Inflammation was evaluated functionally (gut permeability), biochemically (myeloperoxydase activity) and histologically. Vagal capsaicin deafferentation did not modify colonic transit time. In TNBS treated groups, inflammation was enhanced by capsaicin pretreatment, as determined by an increased gut permeability, MPO activity, and histological damage score. These results suggest that vagal afferents have a protective role in TNBS-induced colitis in rats, unrelated to changes in colonic transit time.

Comparative effects of nonpeptide tachykinin receptor antagonists on experimental gut inflammation in rats and guinea-pigs

Previous studies have shown tachykinins implicated in gut inflammation. The aim of this work was to evaluate the effect of treatments with tachykinin NK1, NK2, and NK3 selective receptor antagonists on the development of gut inflammation induced by trinitrobenzenesulfonic acid (TNBS) in rats and guinea-pigs. On day 0, rats and guinea-pigs received an intraluminal instillation of TNBS/ethanol (40 mg/kg). Each group was daily treated with intraperitoneally injected NK1 (SR 140333; 0.3 mg/kg/day), NK2 (SR 48968; 5 mg/kg/day), or NK3 (SR 142801; 1, 5, or 10 mg/kg/day) receptor antagonists or their vehicle. On day 4, inflammatory levels were evaluated by measuring gut permeability, myeloperoxidase activity, macro- and microscopic damage scores. In TNBS treated rats, daily administration of SR 140333 (0.3 mg/kg/day) and SR 48968 (5 mg/kg/day) reduced colonic inflammation. In TNBS treated guinea-pigs, daily administration of SR 48968 (5 mg/kg/day) and SR 142801 (at 5 and 10 mg/kg/day) attenuated significantly ileal injury. These results suggest that non-peptide tachykinin receptor antagonists are potent anti-inflammatory agents on gut inflammation in rats and guinea-pigs. However, their activity depends upon the animal species and type of receptor considered.

Diagnosis of a C-2 fracture during physiatric consultation: a case report

Consultation in the acute care setting allows physiatrists to make significant contributions. In our case, a 90-year-old woman presented to the emergency room after falling down five stairs. Six view C-spine films taken at that time revealed no fracture. She was sent home on anti-inflammatory medication and was later admitted for gastritis. A repeat six-view C-spine series again revealed no fracture. Physiatry was then consulted to prescribe modalities and therapies for "cervical strain." On examination, the patient demonstrated severely decreased neck range of motion limited by pain, with pain radiating down her right arm. Physiatry recommended obtaining a C-spine magnetic resonance image to rule out occult fracture or herniated disc before proceeding with therapies. The magnetic resonance image revealed a complex C-2 fracture consisting of a Type III odontoid component. Computed tomographic scan was then performed to obtain a high-resolution assessment of the bony architecture. The computed tomographic scan revealed a high degree of comminution, including bilateral pedicle fractures and a fracture through the left transverse foramen of C-2. The patient was placed in a hard cervical collar and seen by a neurosurgeon. Had therapies been initiated before physiatric consultation, the patient could have experienced significant neurologic complications, including the possibility of becoming tetraplegic. This case demonstrates that physiatrists play a crucial role in the evaluation of acute care patients before the initiation of therapies. The authors will review pertinent history and the results of physical and diagnostic tests.

Brain Fos expression and intestinal motor alterations during nematode-induced inflammation in the rat

Brain-gut interactions and intestinal motility were studied during pulmonary and jejunal inflammation induced by Nippostrongylus brasiliensis. Jejunal electromyographic activity was continuously recorded from day 1 before to day 28 after infection. Expression of c-fos was assessed in the brain by immunohistochemistry, and myeloperoxidase (MPO) activity was determined in lung and intestine on days 1,7,14, 21, and 28 postinfection. The cyclic intestinal motor pattern was replaced by an irregular activity from day 4, corresponding to larvae migration to the intestine, to day 14. c-fos was expressed in the caudal nucleus of the solitary tract (NTS) and lateral parabrachial nucleus (LPB) on day 1 (lung stage of N. brasiliensis) and in the medial part of the NTS, the LPB, and locus ceruleus on day 7. Pulmonary and intestinal MPO activity was increased from days 1 to 21 postinfection. During N. brasiliensis infection, c-fos expression indicates that specific and different brain nuclei are activated at the onset of pulmonary and intestinal inflammation, which is associated with motor disorders.

Evidence for mast cell, leukotriene and nitric oxide involvement in the regulation of the adrenoceptor number of inflamed small intestine in guinea pigs

Changes in the populations of neurotransmitter receptors involved in the control of intestinal smooth muscle function have been associated with the altered motility of the inflamed gut. Thus, trinitrobenzenesulphonic acid (TNBS)-induced gut inflammation is accompanied by an increase in alpha- and a decrease in beta-adrenoceptor numbers in guinea pig small intestine. In the present study, we investigated the effects of anti-inflammatory compounds (cyclooxygenase inhibitor indomethacin, lipooxygenase inhibitor MK-886, nitric oxide synthase inhibitor NG-nitro-L-arginine methylester (L-NAME), mast cell stabilizer doxantrazole) on TNBS-induced adrenoceptor changes. Smooth muscle adrenoceptor populations, labelled by subtype-specific radioligands 6 days after TNBS, were significantly different from those of sham-treated controls: alpha 1- and alpha 2-adrenoceptor numbers increased by more than 50%, while beta-adrenoceptor numbers decreased by more than 50%. These changes, associated with severe inflammation as assessed histologically and by myeloperoxidase assay, were prevented by doxantrazole or L-NAME, and only partly by MK-886. In contrast, indomethacin did not prevent these changes. It appears then that: (a) mast cell mediators, nitric oxide and leukotrienes are likely to contribute to TNBS-induced changes in adrenoceptor populations in the guinea pig inflamed intestine; (b) there is no evidence for prostanoid involvement in this process. It was suggested that changes in smooth muscle adrenoceptor populations may be an important mechanism by which gut inflammation alters intestinal motility.

Boosted systemic immune and local responsiveness after intestinal inflammation in orally sensitized guinea pigs

BACKGROUND & AIMS

Intestinal inflammation resulting in disruption of the mucosal barrier function has been proposed as a cause of increased incidence of allergic diseases. This study was designed to evaluate whether intestinal inflammation is able to change the immune responsiveness to sensitization and antigen challenge responses.

METHODS

Guinea pigs orally sensitized to cow's milk proteins were either treated or not treated with trinitrobenzenesulfonic acid (TNBS) to induce intestinal inflammation and compared with control animals (not sensitized). Systemic immune and local responsiveness to antigen challenge were assessed by measuring antibody serum titers, colonic fluid secretion, mucosal histamine level, and mucus depletion. Intestinal permeability was evaluated from 51Cr-ethylenediaminetetraacetic acid (EDTA) recovery and beta-lactoglobulin serum level.

RESULTS

Immunoglobulin E titers were higher in TNBS-treated animals than in non-TNBS-treated sensitized animals. Antigen challenge in TNBS-treated animals induced a fourfold increase of colonic secretion and greater histamine and mucus depletion than in non-TNBS-treated animals. Permeability to 51Cr-EDTA increased 5 days after TNBS treatment but was unchanged after antigen challenge. In contrast to controls, beta-lactoglobulin was not detected in the sera of challenged sensitized and TNBS-treated animals.

CONCLUSIONS

Intestinal inflammation increasing gut permeability enhances the sensitization process. Therefore, local anaphylactic reactions are exacerbated after antigen challenge.

Role of 5-HT3 receptors and afferent fibers in the effects of mast cell degranulation on colonic motility in rats

BACKGROUND/AIMS

Mediators released by mast cell degranulation contribute to digestive motility disturbances. According to the role of serotonin and the close proximity of mast cells to nerves, the aim of this study was to assess the role of 5-hydroxytryptamine 3 (5-HT3) receptors, capsaicin-sensitive afferent fibers, and some of their neuropeptides (substance P and calcitonin gene-related peptide) in colonic motor alterations induced by degranulation of mast cells by the compound BrX-537A.

METHODS

The effects of BrX-537A (2 mg/kg intraperitoneally) were determined by electromyography in conscious rats implanted with electrodes in the cecocolonic wall.

RESULTS

BrX-537A inhibited cecocolonic myoelectric activity for 7-8 hours. A primary and dramatic reduction of spike burst frequency, lasting 30 minutes, was affected by none of the pretreatments tested. The following inhibition was fully antagonized by ketotifen (mast cell stabilizer), granisetron and ondansetron (5-HT3 antagonists), RP-67,580 (NK1 antagonist), and perivagal capsaicin pretreatment. A temporary blockade was observed after administration of CP-96,345 (NK1 antagonist) and in rats systemically treated by capsaicin. The calcitonin gene-related peptide antagonist hCGRP(8-37) did not modify the BrX-537A-induced inhibition.

CONCLUSIONS

5-HT3 receptors, sensory afferent fibers reaching the vagus nerves, and substance P are major components of the colonic motor inhibition induced by mast cell degranulation.

Neurosurgical management of the rheumatoid cervical spine

Rheumatoid arthritis affects the cervical spine in up to 88% of patients with seropositive disease. Neurologic sequelae result either from direct compression by a rheumatoid pannus or from spinal subluxations. Indications for and techniques of neurosurgical intervention are discussed.

Preparation of a gelatin-binding conjugate containing gold thiomalate

Plasma fibronectin has a range of binding sites, for ligands, including denaturated collagen (gelatin). It has been proposed that this activity may be used for nonimmune drug targeting to sites in the extra-cellular matrix such as the targeting of gold thiomalate to rheumatoid joints. In the present study, a novel conjugate has been developed, consisting of the gold thiomalate bound at high density to the gelatin-binding domain of fibronectin, through a polylysine carrier. Isolation and cross-linking of suitable fragments of fibronectin (relative molecular weights 65 and 52 kDa) to polylysine is followed by conjugation to gold thiomalate on a solid phase, gelatin-agarose affinity absorbent. Although gold thiomalate has the ability to inactivate, the protein-gold conjugate produced by this technique retained its gelatin-binding activity.

Platelet-activating factor and interleukin 1 are involved in colonic dysmotility in experimental colitis in rats

BACKGROUND

Intracolonic administration of trinitrobenzene sulfonic acid (TNBS) to rats produces chronic colitis associated with an increased release of eicosanoids, platelet-activating factor (PAF), and interleukins.

METHODS

Motor effects of TNBS on proximal colon were evaluated electromyographically in rats. Mediator involvement was investigated using eicosanoids and PAF antagonists.

RESULTS

The colonic myoelectrical activity was 59 +/- 17 spike bursts per hour lasting 6.9 +/- 1.3 seconds. Two to eight days after TNBS treatment, spike-burst duration was significantly (P < 0.05) higher, with a maximal 1.5-4-fold enhancement at day 3. These alterations were significantly (P < 0.05) reduced by daily treatment with MK-886, a 5-lipoxygenase inhibitor (10 mg/kg, orally), whereas indomethacin (1 mg/kg per day, intramuscularly) was ineffective. At day 3, RP55778, a PAF antagonist (45, 60 mg/kg, intraperitoneally), and rIRAP, an interleukin 1 antagonist (0.3 mg/kg, intraperitoneally) but not KT1-32, a thromboxane A2 antagonist (30, 60 mg/kg orally), nor SKF104,353, a leukotriene D4 antagonist (2, 4 mg/kg, orally), significantly (P < 0.05) reduced the TNB-induced motor effects.

CONCLUSION

TNBS-induced colitis in rats involves a delayed long-lasting dysmotility involving PAF, interleukin 1, and some leukotrienes but not leukotriene D4, thromboxane A2, or other cyclo-oxygenase products.

[Multicenter study of fluconazole in the treatment of oropharyngeal candidiasis in immunodepressed patients]

We have evaluated the efficacy of fluconazole, 50 mg/day for 2 weeks, to treat oropharyngeal candidiasis in immunologically compromised patients. There were overall 27 patients, 25 of which were HIV+ and 2 had neutropenia. The rate of clinical response at the end of therapy, and one week and one month afterwards were 96%, 76% and 64%, respectively. The microbiological eradication was achieved in 36% of patients. The tolerance of the drug was satisfactory, although in 3 cases features of hepatic toxicity were detected. The convenience, good tolerance and clinical efficacy of fluconazole make it the therapy of choice for oropharyngeal candidiasis in immunologically compromised patients.

A monoclonal antibody to human insulin-like growth factor-I: characterization, use in radioimmunoassay and effect on the biological activities of the growth factor

A monoclonal antibody (BPL-M23) to insulin-like growth factor-I (IGF-I) was obtained following immunization of BALB/c mice with human IGF-I conjugated to ovalbumin. The affinity constant of BPL-M23 for IGF-I was 10.5 litres/nmol and the cross-reactivities of IGF-II, multiplication-stimulating activity III-2 and insulin were 0.8, 0.03 and less than 0.0001% respectively. Porcine, bovine, ovine and rabbit sera, but not rat or mouse sera, showed substantial reactivity with the antibody. Comparison of radioimmunoassay analyses of 54 human serum samples from normal subjects and acromegalic and GH-deficient patients using BPL-M23 and a polyclonal rabbit antiserum (R557A) to human IGF-I showed a high correlation, indicating the usefulness of the monoclonal antibody in radioimmunoassay. Monoclonal antibody BPL-M23 was capable of abolishing the sulphation, mitogenic and insulin-like activities of IGF-I in in-vitro bioassays, suggesting that these activities may rely upon the same receptor-binding site which is near to the antibody-binding site.

The urethral muscle (musculus urethralis) of the female calf. Anatomical, histological, histochemical and morphometrical data

Parts of the female urethra were examined topographically and microscopically in the female calf. The thickness and the straight course of the fibres of the musculus urethralis could best be analyzed in the ventromedian region of the urethra. Examination of the surface area and the distribution of the two primary metabolic fibre types showed that the urethral muscle is capable of contracting quickly with predominantly anaerobic metabolism. The different relationships between type I and type II fibres could be determined also in relation to the position of the lamina propria mucosae.

Nifedipine in the treatment of renal colic

A double-blind randomized, clinical trial was conducted in 43 patients to evaluate the efficacy of sublingual nifedipine in the treatment of pain in renal colic. Comparison was made with a combination of dipyrone, pitofenone and fenpipramide, which is usually administered intravenously in Spain. With nifedipine, pain completely disappeared in 44% of the cases, and with the combination of drugs, in 89% (p less than 0.005). More adverse effects were noted with the combination than with nifedipine. Both treatments brought about a slight drop in arterial pressure without leading to hypotension in any case. There was no change in heart rate. The possible causes of the relatively low level of success with nifedipine were analyzed. The possibility of using nifedipine under certain circumstances in which other drugs are contraindicated or when their administration is unfeasible is suggested.

An in vivo model for pharmacokinetic studies in the kidney

In order to assess drug renal kinetics in vivo, the two kidneys of seven ewes were surgically placed under the skin. Through the use of renal function tests and a series of biopsies, we found that the kidneys remained normal in their subcutaneous location. Gentamicin renal kinetics were evaluated in conscious animals by a series of biopsies. Histological controls showed only slight lesions due to biopsy; based upon plasma hydrocortisone concentration, there was no indication of chronic stress affecting the renal pharmacokinetics. We suggest that this model has great potential as a method for studying in vivo the kinetics of drug disposition in the renal tissue and assessing the residue level of a drug.

Impairment of drug metabolism by the liver in experimental fascioliasis in the rat

Fascioliasis has been produced in the rat by an oral administration of 20 metacercariae of Fasciola hepatica. Hepatic microsomal cytochrome P450 and b5 contents and both aminopyrine demethylase and aniline hydroxylase activities have been measured during the course of the experimental distomiasis. The cytochrome P450 concentration and microsomal drug metabolizing enzymes generally fell by weeks 3 to 8 post-infestation and recovered to normal values thereafter. For the same period, both the histoenzymatically assayed liver cytochrome oxidase and arylsulphatase activities were reduced whereas there were correlated increases in glutamic pyruvic and glutamic oxaloacetic plasma transaminases. Tissue inflammation and destruction provoked by young histophagous migrating flukes could be responsible for these changes that have already been observed in several hepatic diseases. The possible influence of naturally-induced fasciolasis on liver drug metabolism is discussed.

Evaluation of the trace metal supplements for a synthetic low lactose diet

A trace element supplement used with a synthetic low lactose milk (Galactomins 17 and 18) has been evaluated by means of metabolic balance studies in 4 infants with dissacharide intolerances. The supplement was considered satisfactory for iron and manganese but increases in its zinc and copper content are probably necessary to ensure adequate retentions of these metals.

Spontaneous motility of the cervix in cyclic and ovariectomized ewes and changes induced by exogenous hormones

Continuous recordings of the electrical and mechanical activities of the cervix were made. Two basic patterns of electrical signal, short spike bursts and long spike bursts, showed close mechanical relationships with the record of mechanical activity. Electrical activity was organized in myoelectrical complexes including the regular alternation of phases of irregular spiking activity and phases of regular spiking activity. The myoelectrical complexes of the cervix existed independently of the sexual status although the frequency of recurrence did vary. The highest frequency was recorded during the periovulatory period around oestrus when each complex was synchronized with a similar pattern recorded from the uterine horns. At the end of the periovulatory period, the irregular spiking activity decreased, the myoelectrical complex pattern of the cervix and uterine horns consisting mainly of regular spiking activity at a high frequency until metoestrus. During the luteal phase, only the cervix remained active, with myoelectrical complexes formed mainly by phases of regular spiking activity recurring at long intervals. This pattern was also recorded after ovariectomy in the absence of hormonal treatment.

Is there a functional large intestine in the ferret?

The intestine of the ferret (Putorius furo) is unusual in that there is no external anatomical division between ileum and colon. Up to 8-10 cm from the anus the electrical activity was organized into migrating myoelectric complexes typical of the small intestine. At this point the pattern of electrical activity changed abruptly to that characteristic of the colon, namely short and long spike burst activity. Histological examination showed that at this point the muscular layers were interrupted by a band of connective tissue sufficient to permit the functional autonomy of the last part of the intestine.

Symptomatic zinc deficiency in a breast-fed preterm infant

A 2-month-old preterm boy who developed symptomatic zinc deficiency while being exclusively breast fed is described. Oral zinc supplements induced a complete remission but mucosal 65Zn uptake studies and metabolic balances conducted before and after withdrawal of the supplements excluded the diagnosis of acrodermatitis enteropathica. By age 12 months the boy was well and no longer required zinc supplements. Other possible causes of this patient's symptomatic zinc deficiency are discussed and these should be considered in the immediate and long-term management of preterm infants.