Behavioral skills training for teaching safety skills to mental health service providers compared to training-as-usual: a pragmatic randomized control trial

BACKGROUND

Violence in the healthcare workplace has been a global concern for over two decades, with a high prevalence of violence towards healthcare workers reported. Workplace violence has become a healthcare quality indicator and embedded in quality improvement initiatives of many healthcare organizations. The Centre for Addiction and Mental Health (CAMH), Canada's largest mental health hospital, provides all clinical staff with mandated staff safety training for self-protection and team-control skills. These skills are to be used as a last resort when a patient is at imminent risk of harm to self or others. The purpose of this study is to compare the effectiveness of two training methods of this mandated staff safety training for workplace violence in a large psychiatric hospital setting.

METHODS

Using a pragmatic randomized control trial design, this study compares two approaches to teaching safety skills CAMH's training-as-usual (TAU) using the 3D approach (description, demonstration and doing) and behavioural skills training (BST), from the field of applied behaviour analysis, using instruction, modeling, practice and feedback loop. Staff were assessed on three outcome measures (competency, mastery and confidence), across three time points: before training (baseline), immediately after training (post-training) and one month later (follow-up). This study was registered with the ISRCTN registry on 06/09/2023 (ISRCTN18133140).

RESULTS

With a sample size of 99 new staff, results indicate that BST was significantly better than TAU in improving observed performance of self-protection and team-control skills. Both methods were associated with improved skills and confidence. However, there was a decrease in skill performance levels at the one-month follow-up for both methods, with BST remaining higher than TAU scores across all three time points. The impact of training improved staff confidence in both training methods and remained high across all three time points.

CONCLUSIONS

The study findings suggest that BST is more effective than TAU in improving safety skills among healthcare workers. However, the retention of skills over time remains a concern, and therefore a single training session without on-the-job-feedback or booster sessions based on objective assessments of skill may not be sufficient. Further research is needed to confirm and expand upon these findings in different settings.

PRN usage before and after discharge from a forensic inpatient unit: A series example of patients with intellectual disabilities

Adults living with intellectual and developmental disabilities are often prescribed psychotropic medication on an "as needed" basis (PRN) in response to behavioural challenges. In the present study we conducted a retrospective analysis of medication administration records in the 6-months preceding and following discharge of 11 adults with intellectual and developmental disabilities to community settings from forensic inpatient units within a mental health hospital. We found a significant reduction in the frequency of PRN usage after discharge. We propose potential reasons for the difference in PRN administration across settings and make suggestions for future research.

Microvascular tissue perfusion after postcatheterization pseudoaneurysm treatment

BACKGROUND

Femoral pseudoaneurysm (PSA) is a severe complication after endovascular procedures. Ultrasound-guided manual compression (MC) and percutaneous thrombin injection (TI) are frequently used treatments. MC is less effective, TI may cause thromboembolic events.

OBJECTIVE

Up to date, there is no data regarding impairment of microvascular tissue perfusion after PSA treatment.

METHODS

In this single-center, prospective study 22 patients with PSA were included. We compared macro- and microcirculatory perfusion in the treated and untreated leg at baseline before, after and one day after treatment. Leg perfusion was assessed with ultrasound and ankle-brachial index (ABI). Microcirculatory perfusion of the feet was measured with a near-infrared spectroscopy (NIRS) camera generating StO2-tissue-maps.

RESULTS

Successful PSA thrombosis was achieved in 16 (100%) patients in TI group and in 4 (66.7%) patients in MC group. There was no evidence of arterial thrombi on ultrasound and the ABI did not differ between groups. NIRS StO2-tissue-maps of the feet showed no significant difference in both groups concerning the treated (p = 0.121) or the untreated (p = 0.198) leg during follow up.

CONCLUSIONS

In this small exploratory study, there was no evidence of micro- and macrovascular tissue perfusion impairment after treatment of postcatheterization femoral pseudoaneurysm with thrombin injection underscoring the safety of this approach.

Behavioral Skills Training for Teaching Safety Skills to Mental Health Clinicians: Protocol for a Pragmatic Randomized Control Trial

BACKGROUND

Workplace violence is an increasingly significant topic, particularly for staff working in mental health settings. The Centre for Addiction and Mental Health (CAMH), Canada's largest mental health hospital, considers workplace safety a high priority and consequently has mandated staff safety training. For clinical staff, key components of this training are self-protection and team-control skills, which are a last resort when an individual is at an imminent risk of harm to self or others and other interventions are ineffective (eg, verbal de-escalation). For the past 20 years, CAMH's training-as-usual (TAU) has been based on a 3D approach (description, demonstration, and doing), but without any competency-based assessment. Recent staff reports indicate that the acquisition and retention of these skills may be problematic and that staff are not always confident in their ability to effectively address workplace violence. The current literature lacks studies that evaluate how staff are trained to acquire these physical skills and consequently provides no recommendations or best practice guidelines. To address these gaps described by the staff and in the literature, we have used an evidence-based approach from the field of applied behavior analysis known as behavioral skills training (BST), which requires trainees to actively execute targeted skills through instruction, modeling, practice, and feedback loop. As part of this method, competency checklists of skills are used with direct observation to determine successful mastery.

OBJECTIVE

Our objectives are to evaluate the effectiveness of BST versus TAU in terms of staff confidence; their competence in self-protection and team-control physical skills; their level of mastery (predefined as 80% competence) in these skills; and their confidence, competency, and mastery at 1 month posttraining.

METHODS

We are using a pragmatic randomized controlled trial design. New staff registering for their mandatory safety training are randomly assigned to sessions which are, in turn, randomly assigned to either the BST or TAU conditions. Attendees are informed and consented into the study at the beginning of training. Differences between those consenting and those not consenting in terms of role and department are tracked to flag potential biases.

RESULTS

This study was internally funded and commenced in January 2021 after receiving ethics approval. As of May 2022, data collection is complete; half of the baseline, posttraining, and 1-month videotapes have been rated, and three-fourths of the interrater reliability checks have been completed. The analysis is expected to begin in late summer 2022 with results submitted for publication by fall 2022.

CONCLUSIONS

The findings from this study are expected to contribute to both the medical education literature as well as to the field of applied behavioral analysis where randomized controlled trial designs are rare. More practically, the results are also expected to inform the continuing development of our institutional staff safety training program.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/39672.

Evaluation and Maintenance of Behavioral Interventions for 22q11.2 Deletion Syndrome

22q11.2-deletion syndrome is a genetic disorder caused by a small deletion of chromosome 22. This deletion often results in developmental delays, learning disabilities, medical conditions, and comorbid psychiatric conditions. Patients with 22q11.2DS may present with a variety of behavioral phenotypes including obsessiveness and rigidity, poor social skills, and anxiety. In some cases, the phenotype can consist of destructive and inappropriate behavior including harming self and others. Behavioral difficulties are reported as one of the most challenging aspects of 22q11.2-deletion syndrome for families of patients, however, few studies have examined behavioral interventions as a possible therapeutic treatment for this population. Using principles derived from operant-behavioral psychology, we conducted functional assessments to determine the environmental correlates of destructive and inappropriate behaviors in two adult men with 22q11.2-deletion syndrome. Subsequently, behavioral interventions based on differential reinforcement were incorporated into each participant's natural environment to eliminate these behaviors. Significant reductions in destructive and inappropriate behavior were observed with both participants and therapeutic gains were maintained at follow-up. We discuss the role of behavioral interventions in combination with appropriate psychotropic medication when addressing challenging behaviors in this population.

Wavelength, dose, skin type and skin model related radical formation in skin

The exposure to sun radiation is indispensable to our health; however, a long-term and high exposure could lead to cell damage, erythema, premature skin aging, and promotion of skin tumors. An underlying pathomechanism is the formation of free radicals which may induce oxidative stress at elevated concentrations. Different skin models, such as porcine-, murine-, human- ex vivo skin, reconstructed human skin (RHS) and human skin in vivo, were investigated during and after irradiation using X- and L-band EPR spectroscopy within different spectral regions (UVC to NIR). The amount of radical formation was quantified with the spin probe PCA and the radical types were measured ex vivo with the spin trap DMPO. The radiation dose influences the types of radicals formed in the skin. While reactive oxygen species (ROS) are always pronounced at low doses, there is an increase in lipid oxygen species (LOS) at high doses. Furthermore, the radical types arise independent from the irradiation wavelength, whereas the general amount of radical formation differs with the irradiation wavelength. Heat pre-stressed porcine skin already starts with higher LOS values. Thus, the radical type ratio might be an indicator of stress and the reversal of ROS/LOS constitutes the point where positive stress turns into negative stress.Compared to light skin types, darker types produce less radicals in the ultraviolet, similar amounts in the visible and higher ones in the infrared spectral region, rendering skin type-specific sun protection a necessity.

Angioplasty of flow limiting stenosis improves left ventricular diastolic dysfunction in patients with peripheral artery disease

Background

Peripheral artery disease (PAD) is associated with hypertension and left ventricular diastolic dysfunction (LVDD).

Objective

We hypothesized that endovascular treatment of flow limiting peripheral stenosis may improve LVDD.

Methods

In this prospective single center trial, 23 patients with PAD Rutherford stage 2–4 were included. Augmentation index (AIx), central systolic blood pressure (cSBP) and ankle brachial index (ABI) were measured at baseline one day before, one day after and at follow up 4 months after angioplasty. LVDD was assessed by echocardiography at baseline and at follow up.

Results

Mean E/E' ratio was significantly lower at follow up (11.9±4.4 to 10.2±4.4; p<0.01). Likewise, left atrial size (17.2±5.3 to 13.6±4.7 mm; p=0.014) decreased significantly, but not left atrial volume index (LAVI, 49.73±21.6 to 38.29±17.3 mL/m2; p=0.062). ABI acutely increased in the intervened leg and remained stable at follow up (0.71±0.13 to 0.84±0.13 to 0.89±0.18; p<0.001). AIx (from 30.5±6.1 to 26.5±9.2; p=0.03) and cSBP (from 133±21 to 126±20 mmHg; p=0.05) acutely decreased after angioplasty. At follow up, there was no significant change in central hemodynamics (AIx, cSBP) as compared to baseline.

Conclusion

Chronic effects of angioplasty are associated with favorable improvement of diastolic function but not central hemodynamics.

Funding Acknowledgement

Type of funding sources: None.

The role of the behavior analyst on interprofessional mental health teams: opportunities for collaboration and enhancing patient care

Patients living with mental illness have needs that span a range of professional disciplines, settings, and service systems. These needs are best addressed through interprofessional collaboration. Behavior analysts can play a valuable role in enhancing patient care as part of the interprofessional mental health team. We provide information about the field of applied behavior analysis and its contribution to the assessment and treatment of patients living with mental health and substance use challenges. We outline how behavior analysts are trained and touch upon the practice of behavior analysis in North America and beyond. We describe collaborative relationships with other mental health professionals and, as an example, review the role of the behavior analyst on interprofessional teams in our mental health and addiction teaching hospital in Canada. We highlight some of the challenges faced by behavior analysts working in the mental health field and offer suggestions to increase their profile and opportunities for collaboration in clinical programs.

Comparison of two simple treatment algorithms for iatrogenic femoral artery pseudoaneurysm: ultrasound guided manual compression vs. ultrasound guided thrombin injection

Background

Postcatheterization femoral pseudoaneurysm (PSA) is a common access site related complication after endovascular procedures with potentially deleterious effect on patient outcome. There is still lack of consensus about the optimal treatment.

Objective

We analyze the incidence of PSA in a large cohort of patients undergoing state of the art procedures in current cardiology, identify independent risk factors for PSA formation and assess our experience in PSA treatment comparing two simple treatment algorithms: ultrasound guided manual compression vs. ultrasound guided thrombin injection as a first line treatment.

Methods and results

In this single-centre, retrospective study 29.802 patients from January 2013 to May 2018 underwent femoral artery catheterization. Sheath removal was carried out according to standard operating procedures of the clinic. In 228 patients, a PSA was diagnosed. Thus, overall incidence of PSA amounted to 0.8%.

Of 228 patients with a PSA, 117 (51%) patients were primarily treated with ultrasound guided manual compression with an overall success rate of 34% at next day follow up. All other patients (n=111, 49%) were primarily treated with ultrasound guided thrombin injection with an overall success rate of 99% at next day follow up. Low rates of periprocedural complications were noted with either hemostasis technique.

Analysis of laboratory characteristics revealed that efficacy of ultrasound guided manual compression is dependent on INR whereas efficacy of ultrasound guided thrombin injection is independent of INR (p=0.0253). There was also a higher rate of significant hemoglobin drop with ultrasound guided manual compression versus ultrasound guided thrombin injection (0.78 mg/dl ± 0.09 vs 0.26 mg/dl ± 0.08, p=0.038). Time to mobilization was significantly shorter after ultrasound guided thrombin injection (UGTI: mean time 23.4 h ± 3.1 h, UGMC: mean time 27.1 h ± 10.2 h, p=0.0002).

Multivariate logistic regression analysis revealed that female gender, age (>75 years), oral anticoagulation and anemia are independent risk factors for PSA formation.

Conclusions

Almost 0.8% of patients undergoing cardiac catheterization via femoral access acquire PSA, for which independent risk factors could be identified. Interventional cardiologist operated ultrasound guided thrombin injection is highly effective and safe as a first line treatment and reduces blood loss compared to ultrasound guided manual compression.

Funding Acknowledgement

Type of funding source: None

Deterioration of peripheral microvascular tissue perfusion after transcatheter aortic valve implantation (TAVI) measured by 2D near-infrared spectroscopy (NIRS)

Background

The data on the effect of transcatheter aortic valve implantation (TAVI) on peripheral microcirculation is scarce. Therefore, in this study, we investigate the changes of peripheral microvascular tissue perfusion before and after TAVI measured by a 2D near-infrared spectroscopy (NIRS) camera. NIRS allows measurement of hemoglobin oxygen saturation (StO2) in the blood perfusing the volume tissue under scrutiny.

Methods

In this prospective, single center study, patients with symptomatic, severe aortic stenosis either planned for elective TAVI procedure or elective cardiac catheterization were included. 2-D StO2 maps of all distal extremities (i.e. hand/foot) were acquired before and after TAVI by using a NIRS camera; macrovascular function of the tibial and forearm arteries was assessed by Doppler ultrasound with spectral analysis including ankle-brachial index (ABI) and applanation tonometry.

Results

26 subjects (19 male, age 83±6 years) undergoing TAVI procedure and 5 subjects (4 male, age 76±10) undergoing cardiac catheterization were included in this trial. In the group undergoing TAVI procedure, 5 patients had diabetes mellitus (19%), one of whom was insulin-dependent, 3 patients had a history of peripheral artery disease (12%) and 1 patient had a history of smoking (4%). TAVI procedure was successful without major complications in all cases.Mean peripheral StO2 decreased significantly on all extremities after TAVI, i.e. right hand (from 71±14% to 61±16%; p=0.01), left hand (from 70±12 to 62±16%; p=0.03), right foot (from 70±11% to 61±15%; p<0.01) and left foot (from 66±15% to 58±14%; p=0.03). ABI did not change after TAVI (right ABI baseline mean 1.08±0.2; Δ0.06; left ABI baseline 1.05; Δ0.05). Macrovascular function of the forearm and tibial arteries did not deteriorate as measured by Doppler ultrasound. Furthermore, aortic mean pressure (from 108±21 mmHg to 87±13 mmHg; p=0.002) and augmentation index (from 34±8 mmHg to 24±8 mmHg; p<0.001) decreased significantly while subendocardial viability ratio (from 128±22 to 147±7; p<0.001), a marker for coronary microvascular function, improved significantly after TAVI. In the group undergoing cardiac catheterization, there were no statistically significant changes in macro- or microvascular function.

Conclusion

This is, to our knowledge, the first study investigating the effect of peripheral microvascular tissue perfusion measured by NIRS after TAVI. Our results show that peripheral microvascular tissue perfusion was significantly deteriorated after TAVI procedure.

StO2 before and after TAVI procedure

Funding Acknowledgement

Type of funding source: None

Relationship between salivary leukotriene B4 levels and salivary mucin or alveolar bone resorption, in subjects with periodontal health and disease

OBJECTIVE

Here we determine the salivary levels of leukotriene B4 (LTB4 ) and its relation with salivary mucin and alveolar bone level.

BACKGROUND

LTB4 is a membrane-derived lipid mediator formed from arachidonic acid. It is among the most potent stimulants of polymorphonuclear leukocytes providing the first host defense against infections. Leukotrienes also induce bone resorption. Because LTB4 is present in the oral cavity the aim of the present study was to explore the role of LTB4 in patients with periodontal disease.

METHODS

Eighty-one subjects were clinically examined and distributed into four groups, namely, clinically healthy, mild, moderate and severe periodontitis, according to periodontal status, classified into values of clinical attachment level and probing pocket depth. Unstimulated saliva was collected for 5 min. Salivary LTB4 was determined by an immune assay method, mucin was determined by a colorimetric method and radiographic assessment used to determine alveolar bone level.

RESULTS

Patients with mild periodontitis showed a decrease in salivary LTB4 levels while patients with severe periodontitis showed increased LTB4 levels. A significant positive correlation was observed between salivary LTB4 and clinical attachment level, salivary mucin concentration or alveolar bone level.

CONCLUSION

The close relation between salivary LTB4 and mucin levels suggested that LTB4 might be involved in the defense mechanism of the oral cavity. The correlation of LTB4 with the alveolar bone level indicates that they are one of the mediators responsible for bone resorption.

Relationship between salivary mucin or amylase and the periodontal status

OBJECTIVE

Here we determine the relationship between salivary levels of mucin and amylase and the clinical parameters of periodontal disease before and after periodontal treatment.

SUBJECTS

Ninety two subjects were clinically examined and distributed into four groups namely clinically healthy, mild, moderate and severe periodontitis, according to the periodontal status, classified according the values of clinical attachment level (CAL) and probing pocket depth (PPD). Unstimulated saliva was collected for 5 min. Salivary proteins, amylase and mucin were determined by colorimetric methods.

RESULTS

A significant positive correlation (P < 0.0001) was observed between salivary mucin, amylase or protein and PPD or CAL before periodontal treatment while flow rate showed a negative correlation. Mucin and amylase output also showed a positive correlation with PPD or CAL. After treatment, the improvement of clinical parameters was accompanied by a diminution of salivary mucin, amylase or protein concentration and output in moderate and severe group.

CONCLUSIONS

The increment of mucin and amylase output in relation to periodontal status indicates that salivary glands respond to the disease by increasing the protective potential of saliva when necessary and return to the normal rate of secretion after the resolution of the inflammatory process.

Values and public acceptability dimensions of sustainable egg production

The attributes of egg production that elicit values-based responses include the price and availability of eggs, environmental impacts, food safety or health concerns, and animal welfare. Different social groups have distinct interests regarding the sustainability of egg production that reflect these diverse values. Current scientifically based knowledge about how values and attitudes in these groups can be characterized is uneven and must be derived from studies conducted at varying times and using incomplete study methods. In general, some producer and consumer interests are translated through markets and are mediated by market mechanisms, whereas others are poorly reflected by economic behavior. An array of survey and focus group research has been performed to elicit consumer and activist beliefs about performance goals they would expect from an egg production system. These studies provide evidence that consumers' market behavior may be at odds with their ethical and political beliefs about performance goals.

A non-invasive device to objectively measure tibial rotation: verification of the device

The purpose of this study was the correlation of the results of a new measurement device for tibial rotation (Rotameter) in comparison with the measurements of a knee navigation system as standard method. In a biomechanical laboratory study, all soft tissues were removed from 20 human cadaveric knees leaving only the intact capsule and the bone. Specific tracers were bicortically fixed in the bone in order to measure tibial rotation using a knee navigation system. The knees were fixed to a custom-made inside-boot to rule out undesirable rotation of the reconstruction inside the Rotameter measurement device. Internal and external rotation values were measured at an applied torque of 5, 10 and 15 Nm. The different methods to evaluate tibial rotation were compared using the Pearson correlation coefficient. The correlations were deemed to be reliable if a value of >or=0.80 was achieved. At 5 Nm of applied torque, high correlations for the internal rotation, external rotation and the entire rotational range were found in the Pearson correlation coefficient between the Rotameter testing device in comparison with the knee navigation system as invasive reference method. These results were also confirmed at an applied torque of 10 and 15 Nm. In conclusion, the Rotameter testing device showed high correlations compared with the knee navigation system as an invasive standard method. It might be used as a non-invasive and easy alternative to investigate tibial rotation.

Endogenous signalling system involved in parotid gland adenosine A(1) receptor-amylase release

AIM

In this study, we have determined signalling pathways involved in adenosine A(1) receptor (A(1) receptor)-dependent stimulation of amylase release in rat parotid gland.

METHODS

Amylase release, binding and cyclic adenosine monophosphate (cAMP) assays, inositol phosphates (IPs) production and nitric oxide synthase (NOS) activity in the presence of cyclopentyl-1,3-dipropylxanthine (CPA) alone or in the presence of different inhibitory drugs were performed.

RESULTS

The binding parameters of specific A(1) antagonist [(3)H]-cyclopentyl 1,3-dipropilxanthine ([(3)H]-DPCPX) in parotid gland membranes show a population of high affinity sites with K(d) (nm) 0.53 +/- 0.06 and B(max) (fmol mg(-1) protein) 122.6 +/- 10.2. CPA stimulation of A(1) receptor exerts an increase in amylase release, IPs accumulation, cAMP production and NOS activity. All these A(1) agonist effects were blocked by the A(1) receptor antagonist DPCPX. Inhibitors of phospholipase C (PLC), calcium/calmodulin (CaM), protein kinase C (PKC), and adenylate cyclase, but not NOS, activities attenuated the CPA stimulatory effect on amylase release. The effect of CPA on amylase release significantly correlated with its action either on cAMP or on IPs accumulation.

CONCLUSION

These results suggest that CPA activation of parotid gland A(1) receptor induces a stimulatory effect on amylase release associated with increased production of cAMP and IPs accumulation. The mechanism appears to occur secondarily to stimulation of phosphoinositide turnover via PLC activation. This, in turn, triggers cascade reactions involving CaM and PKC. The CPA stimulation of NOS does not appear to participate in amylase release.

Nitric oxide synthase/PGE(2) cross-talk in rat submandibular gland

It is known that nitric oxide modulates the prostaglandin generation. However, little is known about the regulatory action of prostaglandin on nitric oxide production. There is a molecular cross-talk between nitric oxide and prostaglandin. Here, we examined biochemical signalling pathways coupled to the prostaglandin E(2) (PGE(2)) receptor related to nitric oxide synthase stimulation in rat submandibular gland. PGE(2) through the stimulation of its own receptor, triggered activation of phosphoinositide turnover (IPs), translocation of protein kinase C (PKC), stimulation of nitric oxide synthase activity (NOS) and increased production of cyclic GMP (cGMP). PGE(2) stimulation of NOS and cGMP production was blunted by agents interfering with calcium influx, calcium/calmodulin and phospholipase C (PLC) activities; while PKC inhibitor was able to stimulate PGE(2) effects. PGE(2) did not evoke amylase release, indicating that NOS/ cGMP pathway were not associated with this enzyme secretion. Our results suggest that this prostanoid could act as vasoactive chemical mediator through its ability to activate NOS-cGMP pathway via own gland membrane receptor.

Comparative effect of antiinflammatory drugs on rat paw edema induced by human sterile dental plaque extract, carrageenan or dextran

The effect of antihistamine (diphenhydramine) or antihistamine and antiserotonin (cyproheptadine) or aspirin-like (acetylsalicylic acid and indomethacin) or corticosteroid (dexamethasone) drugs on the edema induced by various doses of carrageenan, dextran or human sterile dental plaque extract, injected intraplantarily in the rat paw were comparatively studied. The results showed that: (a) human dental plaque extract injected into the rat paw induces a dose-dependent inflammatory response, confirming that it is a potent phlogistic agent; (b) the edema induced by the plaque extract though closer to the pattern of carrageenan-induced edema, was different to both the carrageenan- and the dextran-induced edema in its time course and the response to antiedema drugs; (c) histamine and serotonin are liberated in the plaque-induced edema but they play no essential role; (d) the inhibitors of arachidonic acid metabolite formation (ASA, indomethacin and dexamethasone) inhibit this inflammation suggesting the presence of prostaglandin-like substances since its first phase.

The development of colon innervation in trisomy 16 mice and Hirschsprungs disease

AIM: To study the colon innervation of trisomy 16 mouse, an animal model for Down’s syndrome, and the expression of protein gene product 9.5 (PGP 9.5) in the stenosed segment of colon in Hirschsprungs disease (HD).

METHODS: Trisomy 16 mouse breeding; cytogenetic analysis of trisomy 16 mice; and PGP 9.5 immunohistochemistry of colons of trisomy 16 mice and HD were carried out.

RESULTS: Compared with their normal littermates, the nervous system of colon in trisomy 16 mice was abnormally developed. There existed developmental delay of muscular plexuses of colon, no submucosal plexus was found in the colon, and there was 5 mm aganglionic bowel aparting from the anus in trisomy 16 mice. The mesentery nerve fibers were as well developed as shown in their normal littermates. Abundant proliferation of PGP 9.5 positive nerve fibers was evealed in the stenosed segment of HD colon.

CONCLUSION: Trisomy 16 mice could serve as an animal model for Hirschsprung’s disease for aganglionic bowel in the distal part of colon. Abundant proliferation of PGP 9.5 positive fibers resulted from extrinsic nerve compensation, since no ganglionic cells were observed in the stenosed segment of the colon in HD. HD has a genetic tendency.

Influence of castration on the response of the rat vas deferens to fluoxetine

Antidepressant drugs such as desipramine and fluoxetine increase norepinephrine (NE) contractile response in rat vas deferens by inhibiting neuronal amine uptake. Fluoxetine, unlike other antidepressants, also inhibits calcium fluxes, which results in an inhibition of maximal NE effect. Since the contractile response of the reproductive tract is under the influence of testosterone, the effect of fluoxetine could be modified according to the endocrine status of the animal. In the present study we evaluated the influence of castration and testosterone replacement (1 mg per 100 g body wt.) on the peripheral action of fluoxetine. Castration was followed by a decrease in vas deferens weight and the appearance of spontaneous activity. Testosterone replacement reversed these effects. Concentration-response curves to NE and calcium were obtained in the absence and the presence of fluoxetine in vasa deferentia from normal, castrated and testosterone-treated castrated rats. After castration the effect of fluoxetine on vas deferens contractility was markedly altered. The spontaneous activity that appears after castration was prevented by fluoxetine and the stimulatory effect on NE-induced contractions was not observed. In contrast, the inhibitory action of fluoxetine on maximal NE effect was increased. Testosterone replacement restored vas deferens response to NE in the presence of fluoxetine. Fluoxetine did not modify the binding parameters of [(3)H]prazosin in vasa deferentia from normal or castrated animals. Cocaine shifted the NE concentration-response curve to the left in all groups, suggesting that the changes in fluoxetine effect following castration were not the result of an alteration of the neuronal uptake mechanism. The nitric oxide synthase inhibitor l-NMMA did not modify vas deferens response to NE in castrated animals either in the absence or presence of fluoxetine. An increased sensitivity to the inhibitory effect of fluoxetine was observed in the calcium concentration-response curves in vasa deferentia from castrated rats, an effect that was reversed by testosterone replacement. The results suggest that the alteration in the responsiveness of vasa deferentia from castrated rats to calcium could be responsible for increased sensitivity to the inhibitory effect of fluoxetine. It is concluded that vas deferens contractile response is testosterone dependent and that this behaviour modifies the effect of drugs such as fluoxetine that have dual effect on contractility.

Fluoxetine modulates norepinephrine contractile effect on rat vas deferens

The aim of this study was to evaluate whether the antidepressant drug fluoxetine could modify rat vas deferens response to norepinephrine (NE), and to compare its effect with that of desipramine and cocaine. Results showed that 10(-5)m fluoxetine produced a super-sensibility of vas deferens to NE. This result was the same as those obtained for 10(-6)m desipramine or cocaine. Since the effect was Na(+)- and Cl(-)-dependent, an inhibitory mechanism of neuronal NE transport was suggested. Fluoxetine did not modify [(3)H]prazosin K(d) or B(max) in rat vas deferens, reinforcing the hypothesis of a pre-synaptic site of action. On the other hand fluoxetine inhibited NE maximal effect. This inhibitory effect could be related to an antagonism of calcium entry through the voltage-dependent calcium channel, since it was partially reverted by increasing calcium concentration and, besides, the drug was able to inhibit the calcium concentration-response curve also. Contractions induced by 5-hydroxytryptamine (5-HT) were not modified in the presence of fluoxetine. It is concluded that fluoxetine modulates rat vas deferens response to low NE concentrations in the same manner as the selective inhibitor of NE neuronal uptake desipramine. This peripheral effect could participate in the modulation of the male reproductive tract observed by these drugs when used in clinical trials.

[Observation on the development of stomach innervation in trisomy 16 mouse, an animal model for Down syndrome]

OBJECTIVE

To study the nervous development in the stomach of trisomy 16 mouse embryos and their normal littermates from embryonic days 13-18 (ED 13-ED 18) by using primary antibody against protein gene product (PGP) 9.5.

METHODS

(A) trisomy 16 mouse breeding; (B) trisomy 16 mouse embryos were confirmed by examining their chromosomes; (C) PGP 9.5 immunohistochemical method.

RESULTS

In normal littermates, the precursor cells from the neural crest migrated into stomach at ED13. Numerous nervous processes connected each other and formed early nervous networks at ED14. Original ganglia appeared in the muscular plexus with very simple arrangement at ED15. The developed myenteric and submucosal plexuses were found at ED16 and ED17 respectively. The myenteric plexus and the internal and external submucosal plexuses were differentiated at ED18. In comparison with the normal littermates, the trisomy 16 mice's stomach nervous development was much slower. Their immature neurons did not appear in the stomach until ED14; the development and differentiation of stomach nervous plexuses were delayed. A clear link was noted between the development of stomach plexuses and the density of PGP 9.5 immunostaining. A semiquantitative analysis and rank sum test of the data showed that the trisomy 16 mouse embryos were markedly retarded in nervous development of stomach, compared with their normal littermates (P<0.05).

CONCLUSION

Trisomy 16 mouse, as an animal model for Down syndrome, has abnormality not only in several systems and organs but also in stomach innervation. This is the first report on delayed nervous development in the stomach of trisomy 16 mice.

Long-term treatment with fluoxetine associates with peripheral effects on rat vas deferens contractility

The aim of this work was to study whether long-term treatment with fluoxetine could induce peripheral effects by modifying vas deferens contractile activity. For this purpose the contractile response to NE, and 5-HT of vas deferens isolated from male Wistar rats that received fluoxetine 10 mg/kg/day i.p., during 21 days, was studied using the isolated organ bath technique. Results show that vas deferens of treated rats presented spontaneous activity, an effect that was abolished by prazosin and isoproterenol and that was not affected by nitroprusside or indomethacin. In addition, fluoxetine did not modify the response to calcium suggesting that spontaneous activity was not a consequence of an abnormal calcium movement. Fluoxetine induced a significant increase in the response of vas deferens to 5-HT and to low NE concentrations while NE maximal effect was unaffected. Fluoxetine treatment did not modify the binding parameters of [3H]-prazosin to vas deferens. It is concluded that long-term treatment with fluoxetine modifies vas deferens contractile activity. This effect could be the result of an alteration of adrenergic neurotransmission and could account for some of the untoward effects observed during clinical course with fluoxetine.

[Intraluminal expansion of a small intestine segment--animal experiment principles and possible clinical application]

In this study we expanded ileal segments of 8 pigs with an intraluminal expander over a period of 6 to 8 weeks till the volume had reached approximately sixfold of the starting volume. The morphological and morphometrical examinations showed flattened villi with elongated crypts and especially an increase in the thickness of the muscularis. The villi appeared flattened through scanning microscopy as well, but the structure of the microvilli was nearly normal. The proliferative activity in the muscularis, estimated immunohistochemically by a monoclonal antibody against PCNA, showed a threefold increase. So it can be assumed, that the increased thickness of the muscle layer was caused not only by muscle cell hypertrophy but also by hyperplasia. The activity of the alpha-glucosidase, a brush border enzyme, was clearly reduced. The minor cause of this effect was the direct damage of the microvilli from the expander, but the major cause was the exclusion of the ileal segment from the small bowel passage and the resulting lack of nutrients. With our technique it seems possible to create an ileum pouch, a stomach substitute or a urinary bladder substitute.

Inhibitory effects of diazepam in rat vas deferens: role of calcium

Diazepam and Ro5-4864 effects on noradrenaline-induced rat vas deferens contractions were studied. We investigated whether central or peripheral type benzodiazepine receptors were involved, by studying the effects of the selective central or peripheral benzodiazepine receptor antagonists, flumazenil (Ro 151788) or PK 11195 respectively. Diazepam interactions with GABA, adenosine, theophylline, and hypercalcic medium (3.5 mM) were studied. Also, we investigate diazepam effect on KCl depolarized vas deferens. Results showed that diazepam (10(-4) to 1.7 x 10 (-4) M) and Ro 5-4864 (10(-5) to 5.5 x 10(-5) M) inhibited NA-induced vas deferens contractions and that neither flumazenil nor PK 11195 antagonized diazepam or Ro 5-4864 inhibitory effects respectively. GABA, adenosine and theophylline did not modify neither NA vas deferens response nor diazepam inhibitory action. Diazepam effect was significantly reduced in and 3.5 mM calcium medium and KCl vas deferens response was inhibited by diazepam 1.3 x 10(-5) and 1.3 x 10(-4) M. It is concluded that in rat vas deferens diazepam effect seems to be related with calcium mobilization.

Lowered plasma erythropoietin in hypoxic rats with kidney tubule lesions

The role of the kidney tubules in the renal formation of erythropoietin is incompletely understood. Therefore, the capability to produce erythropoietin in response to hypoxia was studied in rats with tubular lesions. Nephron damage was induced in two different ways. First, rats were treated with the nephrotoxic aminoglycoside gentamicin (67.5 mg/kg and day) for 14 days. The animals were then subjected to simulated altitude (6,800 m) for 6 h. The resulting plasma erythropoietin concentration was significantly lower (0.5 IU/ml) than in saline treated control rats exposed to hypoxia (1.0 IU/ml). Second, unilateral hydronephrosis was induced by ureteral ligation. The contralateral kidney was removed immediately before the animals were exposed to simulated altitude for 6 h. The plasma erythropoietin concentration in the ureter-ligated rats did not increase above the value (0.3 IU/ml) in hypoxia exposed anephric rats. These results indicate that the production of erythropoietin is reduced following tubular injury. Tubule cells may directly produce the hormone or interfere with the O2-sensing mechanisms controlling its synthesis. The latter hypothesis would seem to be supported by our failure to demonstrate in vitro erythropoietin production by the two established kidney tubule cell lines, LLC-PK1 and PK-15.

Effects of hydrostatic pressure on fluid transfer by the isolated gallbladder

The influence of hydrostatic pressure elevation on fluid absorption by the isolated guinea pig gallbladder was determined following addition of various smooth muscle spasmogens to the serosal bathing medium. Acetylcholine, prostaglandin E1 and ouabain increased intraluminal pressure from about 4 cm H2O to 13 cm H2O. The pressure increase was associated with a marked but transient stimulation in fluid transfer. The same phenomenon was observed following an increase in hydrostatic pressure by addition of Ringer's solution to the gallbladder lumen. Evidence is presented to support the hypothesis that this phenomenon represents the extrusion of an edema from the gallbladder wall. Two observations favour this explanation: 1. The wet weights of gallbladder subjected to high intraluminal hydrostatic pressure were only one third of those at low pressure. 2. Microscopic examination of the wall of gallbladders at low pressure showed a marked submucosal edema.

[Early alterations of the conjunctiva after alkali-burning (author's transl)]

Early alterations of the conjunctiva after alkaliburning (with 0.25 N NaOH) are described. After chemical damage, there is a nearly total loss of conjunctival epithelium, with simultaneous marked edema in the lower conjunctival parts. Alterations of the surface are examined by scanning electronic microscopy (SEM). Within 24 h marked infiltration of round cells into the conjunctival stroma takes place. After burning, we find a rapid decrease in the ATP level in the conjunctiva to about one-tenth of the normal value, whereas glucose and lactate showed only small alterations before and after chemical injury.