Luminal stimuli acutely sensitize visceromotor responses to distension of the rat stomach

Inflammation can enhance responses to different stimuli consistent with the development of hypersensitivity. To determine whether sequentially applied stimuli interact, we determined visceromotor responses (VMR) to gastric distension, measured at baseline and 60 min after instillation of saline, glycocholic acid (GCA) or ethanol through a gastrostomy in controls and rats with gastric ulcers. In another series of experiments, chemicals were administered before and 60 min after repeated distension of the stomach. Ethanol, but not saline or GCA, increased VMR in controls with a more significant rise in rats with gastric ulcerations. GCA increased responses to gastric distension in controls, whereas GCA and ethanol enhanced responses to gastric distensions in rats with gastric ulcers. Responses to saline, GCA, or ethanol were not affected by repeated noxious distension of the stomach. Luminal stimuli can trigger visceromotor responses and sensitize gastric afferents to mechanical stimulation, thus potentially contributing to dyspeptic symptoms.

The use of telomere biology to identify and develop superior nitrone based anti-oxidants

We have employed a biological chemistry approach to dissect the mechanisms underpinning cellular responses to oxidant stress and to develop biologically relevant anti-oxidants. We have used telomere biology to define cellular stress responses and have observed telomere independent, p21- and p16-dependent stasis following oxidative insult in human fibroblasts. This was accompanied by a [corrected] reduction in XRCC5 expression and a reduction in [corrected] SIRT 1 expression. Using these markers in conjunction with senescence-associated beta-galactosidase expression, we have developed and screened novel nitrone based anti-oxidant compounds. We have identified functional compounds that are unsuitable for use in primary human cells. This has allowed subsequent identification of suitably structured compounds that act as superior biological anti-oxidants, which have potential for use in clinical interventions.

Experimentally induced ulcers and gastric sensory-motor function in rats

Prior studies have demonstrated that inflammation can sensitize visceral afferent neurons, contributing to the development of hyperalgesia. We hypothesized that both afferent and efferent pathways are affected, resulting in changes in motor and sensory function. Kissing ulcers (KU) were induced in the distal stomach by injecting 60% acetic acid for 45 s into a clamped area of the stomach. In controls, saline was injected into the stomach. A balloon catheter was surgically placed into the stomach, and electromyographic responses to gastric distension were recorded from the acromiotrapezius muscle at various times after ulcer induction. The accommodation reflex was assessed by slowly infusing saline into the distally occluded stomach. Gastric pressure changes in response to vagal stimulation were measured in anesthetized rats. Contractile function of circular muscle strips was examined in vitro using force-displacement transducers. KU caused gastric hypersensitivity that persisted for at least 14 days. Fluid distension of the stomach led to a rapid pressure increase in KU but not in control animals, consistent with an impaired accommodation reflex. Gastric ulcers enhanced the contractile response to vagal stimulation, whereas the effect of cholinergic stimulation on smooth muscle in vitro was not changed. These data suggest that inflammation directly alters gastric sensory and motor function. Increased activation of afferents will trigger vagovagal reflexes, thereby further changing motility and indirectly activating sensory neurons. Thus afferent and efferent pathways both contribute to the development of dyspeptic symptoms.

Gastric ulcers evoke hyperexcitability and enhance P2X receptor function in rat gastric sensory neurons

Tissue inflammation contributes to the development of hyperalgesia, which is at least in part due to altered properties of primary afferent neurons. We hypothesized that gastric ulcers enhance the excitability of gastric sensory neurons and increase their response to purinergic agonists. The rat stomach was surgically exposed, and a retrograde tracer [1.1'-dioctadecyl-3,3,3,'3-tetramethylindocarbocyanine methanesulfonate (DiI)] was injected into the wall of the distal stomach. Kissing ulcers (KUs) were produced by a single injection of acetic acid (0.1 ml for 45 s; 60%) into the clamped gastric lumen. Saline injection served as control. Gastric nodose ganglion (NG) or dorsal root ganglion (DRG) cells were harvested 7 days later and acutely dissociated for whole cell recordings. Based on whole cell capacitance, gastric DRG neurons exhibited larger cell size than NG neurons. Significantly more control gastric DRG neurons compared with NG counterparts had TTX-resistant action potentials. Almost all control NG neurons (90%) compared with significantly less DRG neurons (< or =38%) responded to ATP or alpha,beta-metATP. Whereas none of the control cells exhibited spontaneous activity, about 20% of the neurons from KU animals generated spontaneous action potentials. KUs enhanced excitability as shown by a decrease in threshold for action potential generation, which was in part due to an increased input resistance. This was associated with an increase in the fraction of neurons with TTX-resistant action potentials and cells responding to capsaicin and purinergic agonists. KU doubled the current density evoked by the P2X receptor agonist alpha,beta-metATP and slowed decay of the slowly desensitizing component of the current without affecting the concentration dependence of the response. These data show that KU sensitizes vagal and spinal gastric afferents by affecting both voltage- and ligand-gated channels, thereby potentially contributing to the development of dyspeptic symptoms.

Increased nerve growth factor expression triggers bladder overactivity

Prior studies have demonstrated an association between visceral inflammation, an increase in nerve growth factor (NGF) expression, and development of hyperalgesia. Because multiple mediators are released during inflammatory processes, we examined the effect of NGF alone using viral gene transfer in vivo. Replication-deficient adenoviral vectors encoding for NGF or beta-galactosidase were injected into the bladder wall. NGF levels were determined with an enzyme-linked immunoabsorbance assay. Cystometrograms were obtained 3 and 5 days after gene transfer by using a surgically implanted bladder catheter in awake male rats. Although the treatment with a control virus did not change NGF levels compared with those of naive animals, the vector encoding for NGF increased NGF protein levels in the bladder 4-fold. Histologically, no evidence of inflammation was noted. Expression of NGF led to bladder overactivity, whereas beta-galactosidase expression was without effect. These data demonstrate that a transient increase in NGF expression without associated inflammation sensitizes visceral reflex pathways, leading to bladder overactivity. Treatment strategies targeting NGF signaling might be useful in disorders involving sensitization of peripheral nerves.

PERSPECTIVE

Growth factors have been implicated in the pathogenesis of inflammatory pain. This study uses gene transfer to demonstrate that NGF sensitizes afferent pathways in the absence of inflammation, making it a potentially relevant treatment target.

Nerve growth factor and gastric hyperalgesia in the rat

We recently demonstrated an association between the development of hyperalgesia and an increase in nerve growth factor (NGF) during gastric inflammation. We hypothesized that block of NGF signalling will blunt injury-induced hyperalgesia. Male Sprague-Dawley rats (300-400 g) were anaesthetized, the stomach was exposed and placed in a circular clamp. Acetic acid (60%) or saline (control) was injected into this area and aspirated 45 s later, resulting in kissing ulcers. A balloon was surgically placed into the stomach and electromyographic responses to gastric distension (GD) were recorded from the acromiotrapezius muscle. Animals received a daily injection of neutralizing NGF antibody or control serum for 5 days. NGF in the stomach wall was measured with an ELISA. The severity of gastric injury was assessed macroscopically and by determination of myeloperoxidase (MPO) activity. Gastric injury enhanced the visceromotor response to GD and increased NGF content. Anti-NGF significantly blunted the development of hyperalgesia and led to a decrease in gastric wall thickness and MPO activity. Increases in NGF contribute to the development of hyperalgesia after gastric injury. This may be partly mediated by direct effects on afferent nerves and indirectly by modulatory effects on the inflammatory response.

The Sustainable Grazing Systems Program: new solutions for livestock producers

The Sustainable Grazing Systems (SGS) Program was established in 1996 to address the issues of declining pasture productivity and sustainability in the high rainfall zone (>600 mm/year) of southern Australia. The program goal was that 'by June 2001, at least 2000 producers in the high rainfall zone will have adopted changes to their grazing systems that can be shown to be at least 10% more profitable, and more sustainable, than those used prior to participating in SGS. A further 5000 producers will have trialed at least part of the recommended changes'. There were 4 interacting activities within SGS, collectively focused on delivering this goal. These were: (i)�a National Experiment to develop the principles and quantify the relationships; (ii) a regional producer network to determine and deliver on local producer priorities; (iii) training and skills development courses; and (iv) integration and management to ensure the goal was met in an efficient and effective manner. Producer input and ownership were considered essential and were built in at all levels of program activity and management. Independent surveys confirmed that SGS assisted large numbers of producers to make substantial change in farm practices. SGS met its goal by developing and delivering knowledge about more profitable and sustainable grazing systems to a network of almost 10 000 livestock producers across southern Australia. Critical elements of SGS included research, skills training and support for producer groups, on-farm trials and demonstrations, and farm-walks for producers to share information and experiences. A 'triple bottom line' approach was adopted to assess and report on the impacts of the program on the financial, social and environmental capital of the grazing industries in the high rainfall zone. In keeping with the triple bottom line approach, this special edition contains papers that report on biophysical, economic, environmental and social aspects of the program.

Thoracic disk herniation: a case report

OBJECTIVE

Thoracic disk herniations are relatively rare events that often mimic other, more serious disorders. This article discusses the case of a patient with thoracic disk herniation who required unusual treatment to aid resolution of her condition.

CLINICAL FEATURES

The patient, who had a complicated history of prior lumbar disk surgery, sustained a fall onto her buttocks and developed low back and bilateral leg pain. Initial suspicion was of reinjury of the L5 disk.

INTERVENTION AND OUTCOME

Light force spinal manipulation, physical therapies, and eventual cosmetic surgery were able to resolve the condition successfully.

CONCLUSIONS

A clinical situation often may require thinking "outside the box" in order for the patient's condition to be resolved. The failure of symptoms to correspond to the suspected condition should increase the suspicion that another problem may be present.

Viability and functional activity of cryopreserved mononuclear cells

Factors that influence viability and function of cryopreserved peripheral blood mononuclear cells (PBMC) were identified on 54 samples from 27 AIDS Clinical Trial Units. PBMC viability ranged from 1 to 96% with a median of 70%, was higher in laboratories with experienced staff, and was not significantly associated with CD4 cell number. Function of cryopreserved PBMC, measured by lymphocyte proliferation, was associated with viability. Preparations with viability greater than or equal to 70% had consistent proliferative responses and were suitable for functional analyses.

A retrospective study of chloral hydrate, meperidine, hydroxyzine, and midazolam regimens used to sedate children for dental care

PURPOSE

The purpose of this retrospective study was twofold: a) to examine the behavior and physiology of pre-school children each sedated with 1 of 3 drug regimens based on patient age, dental needs, and pre-operative clinical impression; and b) to determine the association between pre-operative behaviors to the behavior and physiology of the sedated children.

METHOD

Records of more than 600 patients sedated at Columbus Children's Hospital dental clinic over a two-year period were culled for patients who ranged in age from 2 to 5 years of age and had received one of three different drug regimens: a) chloral hydrate and hydroxyzine (CH-H), b) chloral hydrate, meperidine, and hydroxyzine (CH-D-H), or c) midazolam (M). A minimum of 300 patients (100/drug regimen) were randomly selected. The standard sedation sheet used in all sedations at the clinic included, among other factors, pre-operative assessments of patient behavior, interaction, and cooperation. Physiological and behavioral variables during the intraoperative sedation periods were also available. These periods included initial baseline vitals, vitals following drug administration, topical and local drug administration, rubber, dam placement, and a minimum of the first 15 minutes of restorative procedures. The three drug regimens were compared for these variables. Data were entered into SPSS for data analysis using one-way ANOVA, Chi-square, regression analysis, and descriptive statistics.

RESULTS

The results indicated significant mean differences in patient age, weight, and duration by drug regimen (F = 20.3, P < 0.001; 16.2, P < 0.001; and 48.7, P < 0.001, respectively). ANOVA indicated a significant difference among drug regimens for percent of quiet, sleeping, and struggling behaviors. Quiet behavior accounted for 26%, 41%, and 67% of all behaviors for CH-H, CH-D-H, and M, respectively. Sleep accounted for 50%, 43%, 0.4% and struggling 11%, 8%, and 19% for CH-H, CH-D-H, and M, respectively. Pre-operative behaviors were also significantly different and patient cooperation was the only variable found minimally predictable of intra-operative behaviors (R = 0.32, P < 0.001). Significant differences among drug regimens were found for heart rate (HR) and mean arterial blood pressure (MAP) during certain procedures (e.g., CH-H produced lower MAP compared to the other drug regimens); however, all physiological variables were within normal limits for the children.

CONCLUSION

Significant differences were found for behavioral and physiological variables among the drug regimens (e.g., CH-D-H produced significantly more quiet and sleeping behaviors than M). Prospective studies are needed to confirm these findings.

Prevalence and patterns of physical restraint use in the acute care setting

Nurse executives usually have the principal responsibility to respond to the national movement to reduce physical restraint use in hospitals. The results of this three-site, interdisciplinary, prospective incidence study (based on more than 49,000 observations collected on 18 randomly selected days) reveal new patterns in the rationale and types of restraints used. The authors discuss how the results can be used in measuring success and allocating resources for restraint reduction programs.

Binding of transcription factors to widely-separated cis-regulatory elements of the murine FGF-4 gene

Embryonal carcinoma (EC) cells and their embryo-derived counterparts, embryonic stem (ES) cells, have been used extensively to study the transcriptional regulation of the fibroblast growth factor-4 (FGF-4) gene. The FGF-4 gene is expressed in EC cells and ES cells, but it is repressed in their retinoic acid (RA)-induced differentiated counterparts. Previous studies have shown that the transcription of the FGF-4 gene is controlled by cis-regulatory elements located in the 5' flanking region of the gene, and by a powerful enhancer located approximately 3 kb downstream from the transcription start site. In the current study, gel mobility shift analysis was used to examine the binding of nuclear proteins to cis-regulatory elements involved in the transcription of the FGF-4 gene. We demonstrate that the transcription factors Sp1 and Sp3 in nuclear extracts prepared from EC cells bind to three Sp1 motifs, one located in the downstream enhancer, and two located in the 5' flanking region of the gene. We also show that Sp1 and Sp3 bind to each of the Sp1 motifs when nuclear extracts prepared from EC-derived differentiated cells are used. In contrast, differentiation of EC cells and ES cells drastically reduces the ability of nuclear factors to bind to an octamer motif and an adjacent High Mobility Group (HMG) motif, which have been shown previously to play essential roles in the functioning of the FGF-4 enhancer. Together, these findings provide a mechanistic explanation of how the distant FGF-4 enhancer promotes transcription of this gene in EC cells and ES cells, and how differentiation of these cells represses transcription of the FGF-4 gene.

Effects of oxidation and reduction on the binding of transcription factors to cis-regulatory elements located in the FGF-4 gene

Previous studies have shown that the addition of reducing agents to the culture medium of embryonic cell lines stimulates their growth. Moreover, recent studies have shown that the redox state of several transcription factors affects their binding to DNA. In light of these findings, we employed gel mobility shift analysis to examine the effects of oxidation and reduction on the ability of transcription factors to bind cis-regulatory elements located in the FGF-4 gene, which is expressed during early mammalian development. In this study, we demonstrate that both the oxidizing agent diamide and the alkylating agent N-ethylmaleimide inhibit the ability of Oct-1, Oct-3, Sp1, and several Sp1-related nuclear proteins to bind important cis-regulatory elements located in the FGF-4 gene. We also demonstrate that not all transcription factors are affected by oxidation. Specifically, we show that the binding of the transcription factor NF-YA, which binds to a critical CCAAT box, and the binding of a high mobility group (HMG) protein(s), which binds to a critical HMG motif, are not affected by diamide or N-ethylmaleimide. Taken together, our findings and those of others support the hypothesis that the redox state of the cell can regulate gene transcription and, thus, can influence important physiological processes.

Blanket use of intranasal mupirocin for outbreak control and long-term prophylaxis of endemic methicillin-resistant Staphylococcus aureus in an open ward

In December 1992, a thoracic ward in a Melbourne teaching hospital experienced an increase in patients infected with methicillin-resistant Staphylococcus aureus (MRSA). It was decided to attempt to control the outbreak by cohorting positive patients (infected and colonized), as well as nurse cohorting, emphasis on handwashing, and use of intranasal mupirocin initially three times a day for three days, then thrice weekly, for all patients in the ward (with or without MRSA). The campaign comprised for phases of 53, 45, 92 and 365 days, respectively. Patient and nurse cohorting stopped at the end of phase I. In phases I and II, surveillance nose swabs were taken on admission, then twice weekly; in phase III, on admission and weekly and in phase IV, on admission until the end of 1993. In phases I and II (98 days), only one patient acquired MRSA. When the frequency of mupirocin prophylaxis was decreased to once weekly (phase III), two patients acquired MRSA in 92 days (no significant difference): thrice weekly administration resumed (phase IV), during which there were three acquisitions in 365 days. The rates of nose colonization of admissions were 6.4%, 6.3%, 9.7% and 3.1% in phase I-IV, respectively. Only three patients were treated with vancomycin between July 1993 and June 1994 (significantly lower than historical rates, P = 0.0086). No mupirocin resistance was seen in MRSA isolates from this ward during phases I, II and III. In areas of low-level endemic MRSA, the blanket use of thrice-weekly intranasal mupirocin may be effective in decreasing serious infections with MRSA, and does not necessarily elicit mupirocin resistance.

Appearance of nuclear protease activity after embryonal carcinoma cells undergo differentiation

Proteolytic systems are involved via multiple mechanisms in the regulation of gene expression, including tightly controlled metabolism of transcription factors. In this study, we demonstrate that differentiation of mouse embryonal carcinoma cells to parietal endoderm-like cells is accompanied by the appearance of nuclear protease activity. Interestingly, this nuclear-associated protease activity is not observed in the visceral endoderm-like cell line, PSA-5E, or in the differentiated cells derived from both mouse embryonic stem cells and the human embryonal carcinoma cell line NT2/D1. We also determined that this differentiation-associated nuclear protease activity causes proteolysis of a wide range of different transcription factors, including ATF-1, Sp1, NF-YA and B, and octamer-binding proteins Oct-1 and Oct-3. Based on the effects of specific inhibitors, the nuclear protease(s) can be classified as a cysteine protease; however, lack of inhibition by calpastatin and EGTA distinguishes this protease activity from the calpain family of proteases. Given the properties of the differentiation-associated nuclear protease(s), we discuss the possibility that this protease(s) plays a role in the metabolism of transcription factors during the differentiation of specific embryonic cells.

Cryptic promoter activity within the backbone of a plasmid commonly used to prepare promoter/reporter gene constructs

This report demonstrates that the plasmids, pBLCAT2 and pBLCAT3, which are used widely for the preparation of promoter reporter gene constructs, exhibit cryptic promoter activity when expressed in embryonal carcinoma (EC) cells and their differentiated cells. The promoterless plasmid pBLCAT3 is used widely because it has two multiple cloning sites. We demonstrate that the activity of the cryptic promoter present in pBLCAT3 is increased dramatically by an enhancerlike region of the murine k-FGF gene. However, the basal cryptic promoter activity and the enhanced cryptic promoter activity can be silenced effectively by the insertion of three tandemly arranged polyadenylation sequences. To characterize the influence of the cryptic promoter in pBLCAT3, we tested its effects on two promoters. Our findings suggest that the cryptic promoter increases by several fold the expression of the reporter gene in pBLCAT2, which contains the thymidine kinase promoter. In contrast, the cryptic promoter present in pBLCAT3 does not seem to influence the expression of the k-FGF promoter. Last, we observed cryptic promoter activity when pBLCAT3 was expressed transiently in EC-differentiated cells. Together, our findings argue that transcription silencing sequences should be used when examining weak promoters in these plasmids, especially in combination with enhancers.

Nearly quantum-limited timing jitter in a self-mode-locked Ti:sapphire laser

The experimentally measured timing jitter of a self-mode-locked Ti:sapphire laser is compared with the theoretically predicted quantum limit. Timing jitter figures of 150 fs (100-500 Hz) and 80 fs (500-5000 Hz), which approach the quantum limit, have been achieved by use of an improved cavity phase-locking technique.

The laryngeal mask airway for intraocular surgery: effects on intraocular pressure and stress responses

Tracheal intubation, performed routinely during general anaesthesia in patients undergoing intraocular surgery, may have adverse effects on cardiovascular function and intraocular pressure. This study assessed the suitability of the laryngeal mask airway (LMA) as a substitute for tracheal intubation. Intraocular and systemic pressor effects, heart rate changes and catecholamine concentrations were measured in two groups of 10 patients receiving standardized anaesthesia with either a tracheal tube (TT) or a LMA. There were significantly smaller changes in the pressor responses to insertion and in concentrations of catecholamines at critical times in the anaesthetic sequence in the LMA group. Mean (SEM) rate-pressure product was significantly smaller in the LMA group compared with the TT group after both insertion (8276 (730) vs 13307 (1348), P < 0.01) and removal (10152 (595) vs 14137 (1044), P < 0.01) of the airway device. The change in intraocular pressure was significantly less in the LMA group at all time points after airway instrumentation than that in the TT group, with the greatest difference after extubation (-2.3 (2.4) mm Hg vs 14.5 (3.4) mm Hg, P < 0.01).

The association of atopic diseases with endometriosis

Comparisons of the incidence of health-related problems were conducted between women with demonstrable endometriosis (N = 88) and a control group (N = 88). Increased incidence of respondents' reports of allergic manifestations (p less than .005) were found. Directions for further research are suggested.