Neoantigen quality predicts immunoediting in survivors of pancreatic cancer.

Cancer immunoediting1 is a hallmark of cancer2 that predicts that lymphocytes kill more immunogenic cancer cells to cause less immunogenic clones to dominate a population. Although proven in mice1,3, whether immunoediting occurs naturally in human cancers remains unclear. Here, to address this, we investigate how 70 human pancreatic cancers evolved over 10 years. We find that, despite having more time to accumulate mutations, rare long-term survivors of pancreatic cancer who have stronger T cell activity in primary tumours develop genetically less heterogeneous recurrent tumours with fewer immunogenic mutations (neoantigens). To quantify whether immunoediting underlies these observations, we infer that a neoantigen is immunogenic (high-quality) by two features-'non-selfness'  based on neoantigen similarity to known antigens4,5, and 'selfness'  based on the antigenic distance required for a neoantigen to differentially bind to the MHC or activate a T cell compared with its wild-type peptide. Using these features, we estimate cancer clone fitness as the aggregate cost of T cells recognizing high-quality neoantigens offset by gains from oncogenic mutations. With this model, we predict the clonal evolution of tumours to reveal that long-term survivors of pancreatic cancer develop recurrent tumours with fewer high-quality neoantigens. Thus, we submit evidence that that the human immune system naturally edits neoantigens. Furthermore, we present a model to predict how immune pressure induces cancer cell populations to evolve over time. More broadly, our results argue that the immune system fundamentally surveils host genetic changes to suppress cancer.

ILC2s amplify PD-1 blockade by activating tissue-specific cancer immunity.

Group 2 innate lymphoid cells (ILC2s) regulate inflammation and immunity in mammalian tissues1,2. Although ILC2s are found in cancers of these tissues3, their roles in cancer immunity and immunotherapy are unclear. Here we show that ILC2s infiltrate pancreatic ductal adenocarcinomas (PDACs) to activate tissue-specific tumour immunity. Interleukin-33 (IL33) activates tumour ILC2s (TILC2s) and CD8+ T cells in orthotopic pancreatic tumours but not heterotopic skin tumours in mice to restrict pancreas-specific tumour growth. Resting and activated TILC2s express the inhibitory checkpoint receptor PD-1. Antibody-mediated PD-1 blockade relieves ILC2 cell-intrinsic PD-1 inhibition to expand TILC2s, augment anti-tumour immunity, and enhance tumour control, identifying activated TILC2s as targets of anti-PD-1 immunotherapy. Finally, both PD-1+ TILC2s and PD-1+ T cells are present in most human PDACs. Our results identify ILC2s as anti-cancer immune cells for PDAC immunotherapy. More broadly, ILC2s emerge as tissue-specific enhancers of cancer immunity that amplify the efficacy of anti-PD-1 immunotherapy. As ILC2s and T cells co-exist in human cancers and share stimulatory and inhibitory pathways, immunotherapeutic strategies to collectively target anti-cancer ILC2s and T cells may be broadly applicable.

Walking Psychotherapy As a Health Promotion Strategy to Improve Mental and Physical Health for Patients and Therapists: Clinical Open-Label Feasibility Trial.

BACKGROUND: Persons with mental illness are more at risk for sedentary behaviour and associated consequences. We assessed the feasibility of outdoor walking during psychotherapy sessions in an outpatient trauma therapy program to challenge sedentary behaviour. METHODS: In this pilot trial in Toronto, Canada, female therapists and patients >18 years, were encouraged to walk during 12 consecutive trauma therapy sessions. Both groups were provided wearable pedometers. We assessed protocol feasibility and desirability, and 12-week changes in patient post-traumatic stress [PTSD check-list for DSM-5 (PCL-5)], and depression, anxiety, and stress symptoms [Depression, Anxiety and Stress Scale (DASS)]. RESULTS: 91% (20/22) of patients approached for the study consented to participate and 17 (85%) completed follow-up questionnaires. There was walking in 132/197 (67%) of total therapy sessions (mean 7.3 out of 10.9 sessions per participant). Inclement weather was the predominant reason for in-office sessions. At 12-week follow-up, PCL-5 mean scores decreased from 38.4 [standard deviation, ((SD) 11.8) to 30.7 (SD 14.7)], [mean difference (MD) 7.7, 95% CI: 1.5 to 13.8]; 41% (7/17) participants had a clinically significant PCL-5 score reduction of >10 points. DASS-stress mean scores decreased from 19.0 to 16.0 (MD 3.0, 95% CI: 0.3 to 5.6). No changes were observed for DASS depression (MD -0.9, 95% CI: -5.1 to 3.3) nor DASS anxiety (MD -0.2, 95% CI: -3.1 to 2.7). Daily step reporting was inconsistent and not analyzed. There was high acceptability amongst patients and therapists to walk, but not to record daily steps. There were no adverse outcomes. CONCLUSIONS: It was feasible and acceptable to incorporate outdoor walking during trauma therapy sessions for patients and therapists. Weather was the greatest barrier to implementation. Further randomized-control study to compare seated and walking psychotherapy can clarify if there are psychotherapeutic and physical benefits with walking.

Hippo Pathway Kinase Mst1 Is Required for Long-Lived Humoral Immunity.

The protein kinase Mst1 is a key component of the evolutionarily conserved Hippo pathway that regulates cell survival, proliferation, differentiation, and migration. In humans, Mst1 deficiency causes primary immunodeficiency. Patients with MST1-null mutations show progressive loss of naive T cells but, paradoxically, mildly elevated serum Ab titers. Nonetheless, the role of Mst1 in humoral immunity remains poorly understood. In this study, we found that early T cell-dependent IgG1 responses in young adult Mst1-deficient mice were largely intact with signs of impaired affinity maturation. However, the established Ag-specific IgG1 titers in Mst1-deficient mice decayed more readily because of a loss of Ag-specific but not the overall bone marrow plasma cells. Despite the impaired affinity and longevity of Ag-specific Abs, Mst1-deficient mice produced plasma cells displaying apparently normal maturation markers with intact migratory and secretory capacities. Intriguingly, in immunized Mst1-deficient mice, T follicular helper cells were hyperactive, expressing higher levels of IL-21, IL-4, and surface CD40L. Accordingly, germinal center B cells progressed more rapidly into the plasma cell lineage, presumably forgoing rigorous affinity maturation processes. Importantly, Mst1-deficient mice had elevated levels of CD138+Blimp1+ splenic plasma cell populations, yet the size of the bone marrow plasma cell population remained normal. Thus, overproduced low-affinity plasma cells from dysregulated germinal centers seem to underlie humoral immune defects in Mst1-deficiency. Our findings imply that vaccination of Mst1-deficient human patients, even at the early stage of life, may fail to establish long-lived high-affinity humoral immunity and that prophylactic Ab replacement therapy can be beneficial to the patients.

Synergistic effects of host B7-H4 deficiency and gemcitabine treatment on tumor regression and anti-tumor T cell immunity in a mouse model.

B7-H4 (B7x/B7S1), a B7 family inhibitor of T cell activity, is expressed in multiple human cancers and correlates with decreased infiltrating lymphocytes and poor prognosis. In murine models, tumor-expressed B7-H4 enhances tumor growth and reduces T cell immunity, and blockade of tumor-B7-H4 rescues T cell activity and lowers tumor burden. This implicates B7-H4 as a target for cancer immunotherapy, yet limits the efficacy of B7-H4 blockade exclusively to patients with B7-H4+ tumors. Given the expression of B7-H4 on host immune cells, we have previously shown that BALB/c mice lacking host B7-H4 have enhanced anti-tumor profiles, yet similar 4T1 tumor growth relative to control. Given that T cell-mediated immunotherapies work best for tumors presenting tumor-associated neoantigens, we further investigated the function of host B7-H4 in the growth of a more immunogenic derivative, 4T1-12B, which is known to elicit strong anti-tumor CD8 T cell responses due to expression of a surrogate tumor-specific antigen, firefly luciferase. Notably, B7-H4 knockout hosts not only mounted greater tumor-associated anti-tumor T cell responses, but also displayed reduced tumors. Additionally, B7-H4-deficiency synergized with gemcitabine to further inhibit tumor growth, often leading to tumor eradication and the generation of protective T cell immunity. These findings imply that inhibition of host B7-H4 can enhance anti-tumor T cell immunity in immunogenic cancers, and can be combined with other anti-cancer therapies to further reduce tumor burden regardless of tumor-B7-H4 positivity.

Host B7-H4 regulates antitumor T cell responses through inhibition of myeloid-derived suppressor cells in a 4T1 tumor transplantation model.

B7-H4, a member of the B7 family of T cell immunomodulatory proteins, has been shown to inhibit T cell responses and neutrophil expansion during bacterial infections. However, the role of B7-H4 in the immune response during tumor growth has been unclear. In this study, we examined the host immune responses in B7-H4-deficient (knockout [KO]) or sufficient (wild-type [WT]) BALB/cJ mice upon transplantation of murine 4T1 carcinoma cells that had little B7-H4 expression. We reveal that host B7-H4 not only dampens the antitumor Th1 responses, but also inhibits the protumor function of myeloid-derived suppressor cells (MDSC). We observed increased expression of both antitumor immune effectors and protumor MDSC-associated transcripts in 4T1 tumors grown in B7-H4 KO mice compared with those grown in WT hosts. Consistently, MDSCs derived from B7-H4 KO mice suppressed T cell proliferation more potently than their WT counterparts. Although the primary growth of 4T1 tumors in B7-H4 KO hosts was similar to that in WT mice, tumors that had grown in B7-H4 KO hosts grew much slower than those from WT mice when subsequently transplanted into WT hosts. Importantly, this differential tumor growth during the secondary transplantation was abrogated when recipient mice lacked T cells, indicating that the immune environment in B7-H4 KO hosts allowed outgrowth of 4T1 tumors with reduced immune-evasive capacities against T cells. Thus, B7-H4 can inhibit both antitumor T cells and protumor MDSCs, influencing the immune-evasive character of the outgrowing tumors. These factors should be considered if B7-H4 blockade is to be used for cancer immunotherapy.

Effects of nimesulide, a selective COX-2 inhibitor, on cardiovascular function in 2 rat models of diabetes.

Cyclooxygenase-2 (COX-2) has been found to be activated in diabetes. We investigated whether nimesulide (selective COX-2 inhibitor) alters cardiovascular responses to adrenaline in 2 rat models of diabetes. Wistar rats (5-week old) were continuously fed a normal or high-fructose diet (60% of caloric intake). At week 2, half of the rats in each diet regimen were given streptozotocin (STZ) (60 mg/kg, intravenously). At week 6, cardiovascular effects of adrenaline (6 and 16 × 10 mol·kg·min, intravenously) were measured in 4 groups of thiobutabarbital-anesthetized rats (control, fructose, STZ, and fructose-streptozotocin [F-STZ]) before and after the injection of nimesulide (3 mg/kg, intravenously). Both the STZ and F-STZ groups exhibited hyperglycemia and significantly (P < 0.05) reduced left ventricular contractility, mean arterial pressure, arterial and venous resistance, and mean circulatory filling pressure (index of venous tone) responses to adrenaline, relative to the control and fructose groups. Nimesulide did not affect responses in the control and fructose groups but increased the venous and, to a less extent, arterial constriction to adrenaline in both the groups of diabetic rats. The cardiac contractile responses, however, were not altered after nimesulide treatment. The results show that nimesulide partially restored arterial and venous constriction to adrenaline in rats with STZ- and F-STZ-induced diabetes.

Association of social support with quality of life in patients with polyneuropathy.

The aim of this study was to examine the impact of social support on quality of life (QoL) in patients with polyneuropathy. One hundred and fifty-four patients with polyneuropathy were enrolled from a neuromuscular clinic. The QoL Instrument and the Medical Outcome Study-Social Support Survey (MOS-SSS) were used to assess QoL and social support, respectively. Disease severity and clinical factors were also assessed. Neuropathy patients had a lower QoL compared to a previously published normative sample (p < 0.0001) and an MOS-SSS comparable to other patients with chronic disease. Social support correlated weakly with the self esteem and emotional well being mental health dimensions (rs :0.20-0.38) but not the physical health QoL (PH-QoL) domains. Physical and mental QoL also correlated significantly with presence of pain (rs : -0.39 and -0.42, respectively) and number of autonomic symptoms (rs : -0.39 and -0.30, respectively). Social support independently predicts MH-QoL when controlling for age, gender, pain, and the Toronto Clinical Neuropathy Score (TCNS; p < 0.0001). TCNS and gender are independently related to PH-QoL (p < 0.05). This study demonstrates that improved social support serves as an independent predictor of MH-QoL when controlling for age, gender, pain, and severity of neuropathy. Future studies examining the effects of improving social support on QoL in patients with polyneuropathy are recommended.

Value of statistical life: adults versus children.

Most studies on the value of statistical life (VOSL) and values for prevention of injuries provide only the average values for the overall population. It is often argued that the values for children may be higher than that for adults because parents are usually more concerned about the mortality and morbidity risks of their children than for themselves. However, it is not an easy task to determine separate VOSLs for children and adults. Only a few empirical results are available and they do not show a definite pattern. Using the results of a value of safety survey carried out in New Zealand in 1997-1998, this paper investigates whether the willingness to pay based VOSL is higher or lower for children. Formal statistical tests were carried out to test the differences and also a regression analysis was carried out to estimate the VOSL separately for adults and children, particularly in households with children. The analysis shows that for the whole sample, the value is higher for children. However, when some outliers were removed the results indicate a higher value for adults than for children. A further trimming shows the value of children is slightly higher. Therefore, no definite conclusion could be drawn. Households without children have the highest VOSL.

Predicting client attendance at further treatment following drug and alcohol detoxification: Theory of Planned Behaviour and Implementation Intentions.

INTRODUCTION AND AIMS: Despite clinical recommendations that further treatment is critical for successful recovery following drug and alcohol detoxification, a large proportion of clients fail to attend treatment after detoxification. In this study, individual factors and constructs based on motivational and volitional models of health behaviour were examined as predictors of post-detoxification treatment attendance. DESIGN AND METHODS: The sample consisted of 220 substance-dependent individuals participating in short-term detoxification programs provided by The Australian Salvation Army. The Theory of Planned Behaviour and Implementation Intentions were used to predict attendance at subsequent treatment. RESULTS: Follow-up data were collected for 177 participants (81%), with 104 (80%) of those participants reporting that they had either attended further formal treatment (e.g. residential rehabilitation programs, outpatient counselling) or mutual support groups in the 2 weeks after leaving the detoxification program. Logistic regression examined the predictors of further treatment attendance. The full model accounted for 21% of the variance in treatment attendance, with attitude and Implementation Intentions contributing significantly to the prediction. DISCUSSION AND CONCLUSIONS: Findings from the present study would suggest that assisting clients to develop a specific treatment plan, as well as helping clients to build positive perceptions about subsequent treatment, will promote greater attendance at further treatment following detoxification. [Kelly PJ, Leung J, Deane FP, Lyons GCB. Predicting client attendance at further treatment following drug and alcohol detoxification: Theory of Planned Behaviour and Implementation Intentions. Drug Alcohol Rev 2016;35:678-685].

Chronic psychological stress in high-anxiety rats induces sustained bladder hyperalgesia.

OBJECTIVE: To evaluate whether anxiety-prone rats exposed to chronic water avoidance stress (WAS) develop visceral bladder hyperalgesia in addition to increased voiding frequency and anxiety-related behaviors. MATERIALS AND METHODS: Female Wistar-Kyoto (WKY) rats were exposed to chronic (10-day) WAS or sham paradigms. Referred hyperalgesia and tactile allodynia were tested using von Frey filaments applied to the suprapubic region and plantar region of the hindpaw, respectively. To confirm that suprapubic nociception represented referred visceral bladder hyperalgesia, we recorded abdominal visceromotor responses (VMR) to slow (100 µl/min) and fast (1 cc/sec) bladder filling with room temperature or ice-cold saline. We assessed the development of hyperalgesia over the 10-day WAS protocol and the durability of increased pain sensations over time. RESULTS: Animals exposed to chronic WAS had significantly lower hindpaw withdrawal thresholds post-stress and significant differences in referred hyperalgesia. Rats exposed to chronic WAS demonstrated an increased pain response to suprapubic stimulation and decreased response threshold to mechanical hindpaw stimulation by day 8 of the stress protocol, which persisted for more than one month. Animals exposed to chronic WAS showed increased VMR to fast filling and ice water testing in comparison to sham animals. Cystometry under anesthesia did not show increases in the frequency of non-voiding contractions. CONCLUSION: Chronic WAS induces sustained bladder hyperalgesia, lasting over a month after exposure to stress. The urinary frequency demonstrated previously in anxiety-prone rats exposed to chronic WAS seems to be associated with bladder hyperalgesia, suggesting that this is a potential model for future studies of bladder hypersensitivity syndromes such as interstitial cystitis/painful bladder syndrome (IC/PBS).

Molecular cloning and expression of rat torsinA in the normal and genetically dystonic (dt) rat.

Deletions within the TOR1A gene cause early-onset (DYT1) torsion dystonia. We have cloned and sequenced the rat cDNA homologue of TOR1A and found a 91% identity with the human sequence. Northern blot analysis detects a single transcript of approximately 1.5 kb. In situ hybridization reveals a widespread distribution of torsinA mRNA within brain. No mutations were identified in the coding region of the gene in the genetically dystonic (dt) rat.

An evaluation of a supplementary road safety package.

A Supplementary Road Safety Package (SRSP) was developed in New Zealand in 1995/1996 to supplement the compulsory breath test (CBT) and speed camera programmes introduced in 1993. A major feature of the package was the use of emotion and shock advertising campaigns not only to affect high risk driving attitudes and behaviours towards speeding and drink-driving but also to encourage the use of safety belts. Furthermore, the SRSP also emphasised targeting enforcement to these three areas. This package continued for 5 years. This paper estimates the effect of the package on road trauma. The analysis shows that the Package made substantial impact on road safety and saved over 285 lives over the 5-year period.

Alcohol in New Zealand road trauma.

Alcohol-impaired driving is one of the major contributing factors to fatal and serious crashes in New Zealand. To curb the high level of road trauma resulting from drink-driving, a compulsory breath test (CBT) programme was introduced in 1993 and a supplementary road safety package (SRSP) in 1995/1996. The SRSP aimed to enhance road safety enforcement and advertising activities, and focused primarily on drink-driving and speeding. These interventions have resulted in a substantial reduction in alcohol-related road trauma. Subsequently, in 1999, the drinking age was lowered from 20 to 18 years. This paper examines the impacts of these drink-driving interventions. The analysis shows that the CBT programme and the SRSP have contributed to the reduction in alcohol-related crashes in recent years. There is also some evidence that, following the lowering of the drinking age, there has been an increase in drink-driving and subsequent alcohol-related crash involvement for drivers under 18 years.

The CD28-B7 Family in Anti-Tumor Immunity: Emerging Concepts in Cancer Immunotherapy.

The interactions between B7 molecules and CD28-family receptors are crucial in the regulation of adaptive cellular immunity. In cancer, the aberrant expression of co-inhibitory B7 molecules has been attributed to reduced anti-tumor immunity and cancer immune evasion, prompting the development of cancer therapeutics that can restore T cell function. Murine tumor models have provided significant support for the targeting of multiple immune checkpoints involving CTLA-4, PD-1, ICOS, B7-H3 and B7-H4 during tumor growth, and clinical studies investigating the therapeutic effects of CTLA-4 and PD-1 blockade have shown exceptionally promising results in patients with advanced melanoma and other cancers. The expression pattern of co-inhibitory B7 ligands in the tumor microenvironment has also been largely correlated with poor patient prognosis, and recent evidence suggests that the presence of several B7 molecules may predict the responsiveness of immunotherapies that rely on pre-existing tumor-associated immune responses. While monotherapies blocking T cell co-inhibition have beneficial effects in reducing tumor burden, combinatorial immunotherapy targeting multiple immune checkpoints involved in various stages of the anti-tumor response has led to the most substantial impact on tumor reduction. In this review, we will examine the contributions of B7- and CD28-family members in the context of cancer development, and discuss the implications of current human findings in cancer immunotherapy.

Cardiovascular effects of acute treatment with the antipsychotic drug olanzapine in rats.

Treatment with antipsychotics is associated with adverse cardiovascular effects such as orthostatic hypotension and arrhythmias. Despite the higher prevalence of cardiovascular complications in patients with schizophrenia, the effects of antipsychotic drugs on vascular tone and cardiac contractility have received little attention. In order to better understand the cardiovascular effects of antipsychotic drugs, we investigated if the atypical antipsychotic olanzapine alters in vivo cardiovascular function in rats. Male Sprague-Dawley rats were prepared with indwelling catheters. After 4 h of recovery from surgery, the mean arterial pressure (MAP), mean circulatory filling pressure (MCFP; index of body venous tone), heart rate, left ventricular peak systolic pressure (LVP) and cardiac contractility (±dP/dt) were measured in conscious, unrestrained rats for 60 min after a single injection of olanzapine (3 or 15 mg/kg, i.p.) or vehicle. Cardiovascular measurements were not altered at any time points in the vehicle-treated rats. Olanzapine did not affect heart rate, but dose-dependently decreased MAP, MCFP, LVP and +dP/dt. Acute olanzapine treatment in rats thus reduced blood pressure and venous tone, as well as cardiac contractile function. Decreased venous tone may be a contributing factor to orthostatic hypotension commonly observed in patients during initiation of antipsychotic therapy.

Inducible costimulator facilitates T-dependent B cell activation by augmenting IL-4 translation.

The inducible costimulator (ICOS) is highly expressed in follicular helper T (Tfh) cells, a subset of CD4 T cells that migrate into the B cell zone and facilitate germinal center reactions. Although ICOS is known to play a critical role in forming the Tfh cell population during immune responses, its contribution to the effector functions of Tfh cells remains unclear. Using activated mouse splenic CD4 T cells we demonstrate that ICOS assists TCR-mediated signal transduction by potentiating the PI3K-AKT-mTOR signaling cascade that leads to hyper-phosphorylation of p70S6K and 4E-BP1, events that are known to augment cap-dependent mRNA translation. Consequently, ICOS costimulation promotes the formation of polysomes on IL-4 mRNA in a PI3K-dependent manner. Furthermore, we show that the supply of IL-4 becomes a limiting factor for T-dependent B cell activation during in vitro co-culture when the ICOS-PI3K signaling axis is disrupted in T cells. This ICOS costimulation-dependent translational control may ensure targeted delivery of IL-4 to cognate B cells during T-B collaborations in the germinal center.

Cardiovascular side-effects of antipsychotic drugs: the role of the autonomic nervous system.

Cardiovascular disease is the leading cause of death in people with severe mental disorders, and rates are proportionally greater than for other diseases such as cancer. Reports of sudden death in patients receiving antipsychotic treatment have raised concerns about the safety of antipsychotic drugs, leading to a number of recent changes in how such drugs are advertised and marketed. The majority of second generation antipsychotic drugs also have significant metabolic side-effects, such as weight gain, insulin resistance and hyperlipidemia, which may contribute indirectly to cardiovascular complications. As the use of antipsychotic drugs continues to expand into new indications and populations such as children and adolescents, a better understanding is needed of how antipsychotic drugs affect the cardiovascular system. Antipsychotic drugs interact with numerous receptors both centrally and peripherally, including monoamine receptors. The direct, non-specific pharmacological actions of antipsychotic drugs can lead to adverse cardiovascular effects, including orthostatic hypotension, tachycardia and ventricular arrhythmias. The mechanisms responsible for these antipsychotic-induced cardiovascular abnormalities have not been fully elucidated, but likely involve blockade of adrenergic or cholinergic receptors and hERG channels, in addition to impaired autonomic function. The direct and indirect effects of antipsychotic drugs on the cardiovascular system and their possible mechanisms of action are discussed in this review, where both preclinical and clinical findings are integrated.

The effects of acute and chronic psychological stress on bladder function in a rodent model.

OBJECTIVE: Psychological stress plays a role in the exacerbation of functional lower urinary tract disorders, such as painful bladder syndrome and overactive bladder. To better understand the mechanism underlying this relationship, we characterized changes in micturition, anxiety-related behavior, and bladder pathology in rats exposed to repeated water avoidance (WA) stress. METHODS: Twenty-four Wistar rats were subjected to WA stress or sham. Immediately after acute (day 1) and chronic (day 10) stress or sham, rats were placed in a metabolic cage for a 2-hour voiding behavior assessment. Voiding parameters were compared with baseline values obtained before stress. Four animals from each group were sacrificed on day 10 and bladders harvested for histologic and gene expression studies. The remaining 8 animals per group underwent repeated voiding assessment every 3 days for 1 month followed by 10 days of repeat WA stress or sham. Bladder histology and gene expression were studied. RESULTS: Rats exposed to WA stress developed a significant increase in micturition frequency and decrease in latency to void, voiding interval, and volume of first void compared with sham and baseline. Alterations in micturition persisted for approximately 1 month. Stressed rats showed increased fecal pellet excretion and anxiety-like behavior. In addition, bladder specimens from stressed animals revealed increased angiogenesis, and increased total and activated mast cells. CONCLUSION: In rats, repeated psychological stress results in lasting alterations in micturition frequency, interval, and volume. This rodent model may represent a valid tool for studying syndromes characterized by increased urinary frequency.

Attenuated alpha-adrenoceptor-mediated arterial and venous constrictions in rat models of diabetes.

Diabetes is associated with metabolic and vascular abnormalities. We investigated if arterial and venous constrictions are impaired in rat models of diabetes. Wistar rats (5 weeks old) were fed a normal or high-fructose diet (60% of caloric intake). On Day 14, half of the animals in each diet regimen were given streptozotocin (60 mg/kg, i.v.). On Day 35, plasma insulin and triglyceride were measured, and on Day 42, insulin sensitivity (via hyperinsulinemic euglycemic clamp), and pressor as well as mean circulatory filling pressure (index of venous tone) responses to noradrenaline were determined. The rats treated with streptozotocin or fructose-streptozotocin were hyperglycemic, hypoinsulinemic and insulin resistant, and they also had reduced potency (increased ED(50)) of pressor response and reduced venoconstriction to noradrenaline compared to the two groups not given streptozotocin. Plasma triglyceride was unchanged in streptozotocin-treated rats, moderately increased in fructose-fed rats, and markedly increased in fructose-streptozotocin-treated rats. Hyperglycemia, insulin resistance and alpha-adrenoceptor-mediated venous contractile dysfunction were more pronounced in the group given fructose-streptozotocin than that given streptozotocin alone. The presence of marked hypertriglyceridemia, insulin resistance and vascular dysfunction makes the fructose-streptozotocin-treated rats a suitable model for study of metabolic and vascular abnormalities in advanced type 2 diabetes.