Neither GLP-1 receptors nor GFRAL neurons are required for aversive or anorectic response to DON (vomitoxin)

Deoxynivalenol (DON), a type B trichothecene mycotoxin contaminating grains, promotes nausea, emesis and anorexia. With DON exposure, circulating levels of intestinally derived satiation hormones, including glucagon-like peptide 1 (GLP-1) are elevated. To directly test whether GLP-1 signaling mediates the effects of DON, we examined the response of GLP-1 or GLP-1R-deficient mice to DON injection. We found comparable anorectic and conditioned taste avoidance learning responses in GLP-1/GLP-1R deficient mice compared to control littermates, suggesting that GLP-1 is not necessary for the effects of DON on food intake and visceral illness. We then used our previously published data from translating ribosome affinity purification with RNA sequencing (TRAP-seq) analysis of area postrema neurons that express the receptor for the circulating cytokine growth differentiation factor (GDF15), growth differentiation factor a-like (GFRAL). Interestingly, this analysis showed that a cell surface receptor for DON, calcium sensing receptor (CaSR), is heavily enriched in GFRAL neurons. Given that GDF15 potently reduces food intake and can cause visceral illness by signaling through GFRAL neurons, we hypothesized that DON may also signal by activating CaSR on GFRAL neurons. Indeed, circulating GDF15 levels are elevated after DON administration but both GFRAL knockout and GFRAL neuron-ablated mice exhibited similar anorectic and conditioned taste avoidance responses compared to WT littermates. Thus, GLP-1 signaling and GFRAL signaling and neurons are not required for DON-induced visceral illness or anorexia.

LPS induces rapid increase in GDF15 levels in mice, rats, and humans but is not required for anorexia in mice

Growth differentiation factor 15 (GDF15), a TGFβ superfamily cytokine, acts through its receptor, cell line-derived neurotrophic factorfamily receptor α-like (GFRAL), to suppress food intake and promote nausea. GDF15 is broadly expressed at low levels but increases in states of disease such as cancer, cachexia, and sepsis. Whether GDF15 is necessary for inducing sepsis-associated anorexia and body weight loss is currently unclear. To test this we used a model of moderate systemic infection in GDF15KO and GFRALKO mice with lipopolysaccharide (LPS) treatment to define the role of GDF15 signaling in infection-mediated physiologic responses. Since physiological responses to LPS depend on housing temperature, we tested the effects of subthermoneutral and thermoneutral conditions on eliciting anorexia and inducing GDF15. Our data demonstrate a conserved LPS-mediated increase in circulating GDF15 levels in mouse, rat, and human. However, we did not detect differences in LPS-induced anorexia between WT and GDF15KO or GFRALKO mice. Furthermore, there were no differences in anorexia or circulating GDF15 levels at either thermoneutral or subthermoneutral housing conditions in LPS-treated mice. These data demonstrate that GDF15 is not necessary to drive food intake suppression in response to moderate doses of LPS.NEW & NOTEWORTHY Although many responses to LPS depend on housing temperature, the anorexic response to LPS does not. LPS results in a potent and rapid increase in circulating levels of GDF15 in mice, rats, and humans. Nevertheless, GDF15 and its receptor (GFRAL) are not required for the anorexic response to systemic LPS administration. The anorexic response to LPS likely involves a myriad of complex physiological alterations.

Sex-Specific Differences in Autophagic Responses to Experimental Ischemic Stroke

Ischemic stroke triggers a series of complex pathophysiological processes including autophagy. Differential activation of autophagy occurs in neurons derived from males versus females after stressors such as nutrient deprivation. Whether autophagy displays sexual dimorphism after ischemic stroke is unknown. We used a cerebral ischemia mouse model (middle cerebral artery occlusion, MCAO) to evaluate the effects of inhibiting autophagy in ischemic brain pathology. We observed that inhibiting autophagy reduced infarct volume in males and ovariectomized females. However, autophagy inhibition enhanced infarct size in females and in ovariectomized females supplemented with estrogen compared to control mice. We also observed that males had increased levels of Beclin1 and LC3 and decreased levels of pULK1 and p62 at 24 h, while females had decreased levels of Beclin1 and increased levels of ATG7. Furthermore, the levels of autophagy markers were increased under basal conditions and after oxygen and glucose deprivation in male neurons compared with female neurons in vitro. E2 supplementation significantly inhibited autophagy only in male neurons, and was beneficial for cell survival only in female neurons. This study shows that autophagy in the ischemic brain differs between the sexes, and that autophagy regulators have different effects in a sex-dependent manner in neurons.

EMMPRIN/CD147 plays a detrimental role in clinical and experimental ischemic stroke

Background: Ischemic stroke is a devastating disease, often resulting in death or permanent neurological deficits. EMMPRIN/CD147 is a plasma membrane protein that induces the production of matrix metalloproteinases (MMPs), which contribute to secondary damage after stroke by disrupting the blood brain barrier (BBB) and facilitating peripheral leukocyte infiltration into the brain.

Results: CD147 surface expression increased significantly after stroke on infiltrating leukocytes, astrocytes and endothelial cells, but not on resident microglia. Inhibition of CD147 reduced MMP levels, decreased ischemic damage, and improved functional, cognitive and histological outcomes after experimental ischemic stroke in both young and aged mice. In stroke patients, high levels of serum CD147 24 hours after stroke predicted poor functional outcome at 12 months. Brain CD147 levels were correlated with MMP-9 and secondary hemorrhage in post-mortem samples from stroke patients.

Conclusions: Acute inhibition of CD147 decreases levels of MMP-9, limits tissue loss, and improves long-term cognitive outcomes following experimental stroke in aged mice. High serum CD147 correlates with poor outcomes in stroke patients. This study identifies CD147 as a novel, clinically relevant target in ischemic stroke.

P5253Does regional myocardial strain by cardiac magnetic resonance feature tracking reflect scar in ischemic heart disease?

Background

Cardiac magnetic resonance (CMR) late gadolinium enhancement (LGE) is the gold standard for detection of myocardial scar. We hypothesized that CMR Feature Tracking (FT)-derived regional myocardial strain may reflect the presence of scar and could thus potentially be used instead of LGE imaging.

Purpose

The aim of this study was to determine the relationship between FT-derived regional myocardial strain and LGE in patients with coronary artery disease (CAD).

Methods

Seventy-five patients with CAD and typical ischemic LGE patterns on CMR (1.5T) were included (mean age 60±12 years, 70% males). Myocardial strain analysis and LGE identification were performed using dedicated commercial software. Scar was defined by presence of LGE in the same area of the myocardium in both short- and long-axis views. Peak systolic regional longitudinal and circumferential strain (RLS, RCS) values were calculated in the region of interest corresponding to the LGE area and also in a non-LGE myocardial region as a reference in each patient. These comparisons were repeated for a subgroup of 36 patients with left ventricular (LV) ejection fraction (EF) <40% to determine whether the relationship between strain and LGE holds in the presence of reduced LV function, when strain measurements may be altered as a reflection of reduced LVEF itself.

Results

Both global longitudinal and circumferential strain values were abnormal (−12.8±5.1% and −11.4±4.1%, respectively), reflecting LV dysfunction in this CAD cohort (EF = 40±16%). The magnitude of both RLS and RCS was significantly reduced in areas of LGE, compared to those without LGE: RLS −10.0±5.8% versus −20.4±7.5% (p<0.001); RCS −10.1±5.3±% versus −18.9±7.5%, respectively (p<0.001). Same pattern was noted in the reduced EF subgroup: RLS −8.0±4.7% versus −16.9±6.6% (p<0.001), RCS −7.7±4.3±% versus −16.0±7.9%, respectively (p<0.001). The figure depicts 2 representative cases in long and short axis views, LGE detection and concomitant regional strain analysis.

LGE and regional strain analysis.

Conclusion

Reduced magnitude of regional longitudinal and circumferential strain by CMR-FT correlates with presence of LGE. Pending further validation, this finding may constitute the basis for detection of scar without contrast enhanced imaging, and would result in reduced cost, scan time and risk associated with gadolinium.

Acknowledgement/Funding

ARP: Research support (software) from Neosoft and Philips

CD200-CD200R1 inhibitory signaling prevents spontaneous bacterial infection and promotes resolution of neuroinflammation and recovery after stroke

BACKGROUND

Ischemic stroke results in a robust inflammatory response within the central nervous system. As the immune-inhibitory CD200-CD200 receptor 1 (CD200R1) signaling axis is a known regulator of immune homeostasis, we hypothesized that it may play a role in post-stroke immune suppression after stroke.

METHODS

In this study, we investigated the role of CD200R1-mediated signaling in stroke using CD200 receptor 1-deficient mice. Mice were subjected to a 60-min middle cerebral artery occlusion and evaluated at days 3 and 7, representing the respective peak and early resolution stages of neuroinflammation in this model of ischemic stroke. Infarct size and behavioral deficits were assessed at both time points. Central and peripheral cellular immune responses were measured using flow cytometry. Bacterial colonization was determined in lung tissue homogenates both after acute stroke and in an LPS model of systemic inflammation.

RESULTS

In wild-type (WT) animals, CD200R1 was expressed on infiltrating monocytes and lymphocytes after stroke but was absent on microglia. Early after ischemia (72 h), CD200R1-knockout (KO) mice had significantly poorer survival rates and an enhanced susceptibility to spontaneous bacterial colonization of the respiratory tract compared to wild-type (WT) controls, despite no difference in infarct or neurological deficits. While the CNS inflammation was resolved by day 7 post-stroke in WT mice, brain-resident microglia and monocyte activation persisted in CD200R1-KO mice, accompanied by a delayed, augmented lymphocyte response. At this time point, CD200R1-KO mice displayed greater weight loss, more severe neurological deficits, and impaired motor function compared to WT. Systemically, CD200R1-KO mice exhibited signs of persistent infection including lymphopenia, T cell activation and memory conversion, and narrowing of the TCR repertoire. These findings were confirmed in a second model of acute neuroinflammation induced by systemic endotoxin challenge.

CONCLUSION

This study defines an essential role of CD200-CD200R1 signaling in stroke. Loss of CD200R1 led to high mortality, increased rates of post-stroke infection, and enhanced entry of peripheral leukocytes into the brain after ischemia, with no increase in infarct size. This suggests that the loss of CD200 receptor leads to enhanced peripheral inflammation that is triggered by brain injury.

Abstract TMP35: CD200-CD200R1 Inhibitory Signaling Attenuates Neuroinflammation and Reduces Behavioral Deficits Following Ischemic Stroke

Introduction: In ischemic stroke, central nervous system homeostasis is dysregulated, leading to a significant inflammatory response, cell death, and impaired neuronal survival. The immune-inhibitory CD200-CD200 Receptor 1 signaling axis is a key regulator of inflammation and CNS homeostasis. We investigated the role of CD200R1-mediated signaling in stroke by evaluating the effects of its genetic deletion on inflammation and neurological outcome.

Methods: Juvenile (10-12 wks) male transgenic CD200R1 knockout and WT littermate control (C57BL/6) mice were subjected to 60-min of reversible right middle cerebral artery occlusion and evaluated at day 3 and 7. Microglia activation and infiltration of peripheral leukocytes were examined by flow cytometry. Behavioral outcome was assessed by open field and rotarod test.

Results: Early after ischemia (72 hrs), CD200R1 KO mice had no differences in stroke outcome measures compared to wildtype controls. However, significantly more infiltrating monocytes were found in the ischemic brain of CD200R1 KO mice. Monocyte function was uniquely affected by CD200R1-deficiency and resulted in dysregulated polarization. Unlike their WT counterparts, which eventually de-escalated the brain’s inflammatory response to stroke, microglia and monocyte activation persisted out to 7 days in CD200R1 KO mice, and was accompanied by a delayed, but significantly augmented lymphocyte response. At this timepoint, CD200R1 KO mice displayed severe weight loss, greater neurological deficits, impaired motor function, and had poorer survival rates compared to their WT counterparts. Interestingly, we found that microglia did not express appreciable levels of CD200R1 surface protein. Instead, CD200R1 was exclusively expressed on infiltrating monocytes and lymphocytes after stroke.

Conclusion: Due to its expression on activated peripheral immune cells after stroke, CD200R1 may be a potentially valuable translational target that can inhibit leukocyte transmigration and thus, dampen the overall amplitude of the inflammatory response. This study defines an essential role for CD200-CD200R1 signaling in down-regulating the neuroinflammatory response in the ischemic brain to facilitate post-acute behavioral recovery.

Multiparity improves outcomes after cerebral ischemia in female mice despite features of increased metabovascular risk

Females show a varying degree of ischemic sensitivity throughout their lifespan, which is not fully explained by hormonal or genetic factors. Epidemiological data suggest that sex-specific life experiences such as pregnancy increase stroke risk. This work evaluated the role of parity on stroke outcome. Age-matched virgin (i.e., nulliparous) and multiparous mice were subjected to 60 min of reversible middle cerebral artery occlusion and evaluated for infarct volume, behavioral recovery, and inflammation. Using an established mating paradigm, fetal microchimeric cells present in maternal mice were also tracked after parturition and stroke. Parity was associated with sedentary behavior, weight gain, and higher triglyceride and cholesterol levels. The multiparous brain exhibited features of immune suppression, with dampened baseline microglial activity. After acute stroke, multiparous mice had smaller infarcts, less glial activation, and less behavioral impairment in the critical recovery window of 72 h. Behavioral recovery was significantly better in multiparous females compared with nulliparous mice 1 mo after stroke. This recovery was accompanied by an increase in poststroke angiogenesis that was correlated with improved performance on sensorimotor and cognitive tests. Multiparous mice had higher levels of VEGF, both at baseline and after stroke. GFP+ fetal cells were detected in the blood and migrated to areas of tissue injury where they adopted endothelial morphology 30 d after injury. Reproductive experience has profound and complex effects on neurovascular health and disease. Inclusion of female mice with reproductive experience in preclinical studies may better reflect the life-long patterning of ischemic stroke risk in women.

Multilocation field trials for risk assessment of a combination fungicide Fluopicolide + Propamocarb in tomato

Dissipation kinetics of two systemic fungicides, namely fluopicolide and propamocarb used as a combination formulation (Infinito 68.75 SC), were studied on tomato at four different locations by the All India Network Project on Pesticide Residues to recommend their pre-harvest interval (PHI) and to propose the maximum residue limits (MRL) for the two fungicides based on chronic hazard exposure assessment. The combination fungicide was sprayed thrice at the recommended dosage of 93.75 g a.i./ha fluopicolide and 937.50 g a.i./ha propamocarb as well as at double the recommended dosage of 187.50 g a.i./ha fluopicolide and 1875.0 g a.i./ha propamocarb on tomato crops and the residues were monitored periodically by GC-MS. The fungicides dissipated to below the limit of quantification (LOQ) within 10 to 15 days, with a half-life of 2-4 days for fluopicolide and 1-2 days for propamocarb. Taking into consideration the MRLs of codex and calculations made using the method of MRL fixation of the Food Safety and Standard Authority of India (FSSAI) as well as the Organization for Economic Co-operation and Development (OECD) calculator, MRL of 5 mg/kg is proposed for fluopicolide and 15 mg/kg for propamocarb, following critical exposure of the commodity considering PHI of 1 day.

Early retinal inflammatory biomarkers in the middle cerebral artery occlusion model of ischemic stroke

PURPOSE

The transient middle cerebral artery occlusion (MCAO) model of stroke is one of the most commonly used models to study focal cerebral ischemia. This procedure also results in the simultaneous occlusion of the ophthalmic artery that supplies the retina. Retinal cell death is seen days after reperfusion and leads to functional deficits; however, the mechanism responsible for this injury has not been investigated. Given that the eye may have a unique ocular immune response to an ischemic challenge, this study examined the inflammatory response to retinal ischemia in the MCAO model.

METHODS

Young male C57B/6 mice were subjected to 90-min transient MCAO and were euthanized at several time points up to 7 days. Transcription of inflammatory cytokines was measured with quantitative real-time PCR, and immune cell activation (e.g., phagocytosis) and migration were assessed with ophthalmoscopy and flow cytometry.

RESULTS

Observation of the affected eye revealed symptoms consistent with Horner's syndrome. Light ophthalmoscopy confirmed the reduced blood flow of the retinal arteries during occlusion. CX3CR1-GFP reporter mice were then employed to evaluate the extent of the ocular microglia and monocyte activation. A significant increase in green fluorescent protein (GFP)-positive macrophages was seen throughout the ischemic area compared to the sham and contralateral control eyes. RT-PCR revealed enhanced expression of the monocyte chemotactic molecule CCL2 early after reperfusion followed by a delayed increase in the proinflammatory cytokine TNF-α. Further analysis of peripheral leukocyte recruitment by flow cytometry determined that monocytes and neutrophils were the predominant immune cells to infiltrate at 72 h. A transient reduction in retinal microglia numbers was also observed, demonstrating the ischemic sensitivity of these cells. Blood-eye barrier permeability to small and large tracer molecules was increased by 72 h. Retinal microglia exhibited enhanced phagocytic activity following MCAO; however, infiltrating myeloid cells were significantly more efficient at phagocytizing material at all time points. Immune homeostasis in the affected eye was largely restored by 7 days.

CONCLUSIONS

This work demonstrates that there is a robust inflammatory response in the eye following MCAO, which may contribute to a worsening of retinal injury and visual impairment. These results mirror what has been observed in the brain after MCAO, suggesting a conserved inflammatory signaling response to ischemia in the central nervous system. Imaging of the eye may therefore serve as a useful non-invasive prognostic indicator of brain injury after MCAO. Future studies are needed to determine whether this inflammatory response is a potential target for therapeutic manipulation in retinal ischemia.

Age-Associated Resident Memory CD8 T Cells in the Central Nervous System Are Primed To Potentiate Inflammation after Ischemic Brain Injury

Aging is associated with an increase in basal inflammation in the CNS and an overall decline in cognitive function and poorer recovery following injury. Growing evidence suggests that leukocyte recruitment to the CNS is also increased with normal aging, but, to date, no systematic evaluation of these age-associated leukocytes has been performed. In this work, the effect of aging on CNS leukocyte recruitment was examined. Aging was associated with more CD45(high) leukocytes, primarily composed of conventional CD8(+) T cells. These results were strain independent and seen in both sexes. Intravascular labeling and immunohistology revealed the presence of parenchymal CD8(+) T cells in several regions of the brain, including the choroid plexus and meninges. These cells had effector memory (CD44(+)CD62L(-)) and tissue-resident phenotypes and expressed markers associated with TCR activation. Analysis of TCRvβ repertoire usage suggested that entry into the CNS is most likely stochastic rather than Ag driven. Correlational analyses revealed a positive association between CD8 T cell numbers and decreased proinflammatory function of microglia. However, the effects of cerebral ischemia and ex vivo stimulation of these cells dramatically increased production of TNF, IFN-γ, and MCP-1/CCL2. Taken together, we identified a novel population of resident memory, immunosurveillant CD8 T cells that represent a hallmark of CNS aging and appear to modify microglia homeostasis under normal conditions, but are primed to potentiate inflammation and leukocyte recruitment following ischemic injury.

Functional differences between microglia and monocytes after ischemic stroke

Background

The brain’s initial innate response to stroke is primarily mediated by microglia, the resident macrophage of the CNS. However, as early as 4 h after stroke, the blood–brain barrier is compromised and monocyte infiltration occurs. The lack of discriminating markers between these two myeloid populations has led many studies to generate conclusions based on the grouping of these two populations. A growing body of evidence now supports the distinct roles played by microglia and monocytes in many disease models.

Methods

Using a flow cytometry approach, combined with ex-vivo functional assays, we were able to distinguish microglia from monocytes using the relative expression of CD45 and assess the function of each cell type following stroke over the course of 7 days.

Results

We found that at 72 h after a 90-min middle cerebral artery occlusion (MCAO), microglia populations decrease whereas monocytes significantly increase in the stroke brain compared to sham. After stroke, BRDU incorporation into monocytes in the bone marrow increased. After recruitment to the ischemic brain, these monocytes accounted for nearly all BRDU-positive macrophages. Inflammatory activity peaked at 72 h. Microglia produced relatively higher reactive oxygen species and TNF, whereas monocytes were the predominant IL-1β producer. Although microglia showed enhanced phagocytic activity after stroke, monocytes had significantly higher phagocytic capacity at 72 h. Interestingly, we found a positive correlation between TNF expression levels and phagocytic activity of microglia after stroke.

Conclusions

In summary, the resident microglia population is vulnerable to the effects of severe ischemia, show compromised cell cycle progression, and adopt a largely pro-inflammatory phenotype after stroke. Infiltrating monocytes are primarily involved with early debris clearance of dying cells. These findings suggest that the early wave of infiltrating monocytes may be beneficial to stroke repair and future therapies aimed at mitigating microglia cell death may prove more effective than attempting to elicit targeted anti-inflammatory responses from damaged cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-015-0329-1) contains supplementary material, which is available to authorized users.

Age- and location-related changes in microglial function

Inflammation in the central nervous system (CNS) is primarily regulated by microglia. No longer considered a homogenous population, microglia display a high degree of heterogeneity, immunological diversity and regional variability in function. Given their low rate of self-renewal, the microenvironment in which microglia reside may play an important role in microglial senescence. This study examines age-related changes in microglia in the brain and spinal cord. Using ex-vivo flow cytometry analyses, functional assays were performed to assess changes in microglial morphology, oxidative stress, cytokine production, and phagocytic activity with age in both the brain and spinal cord. The regional CNS environment had a significant effect on microglial activity with age. Blood-CNS barrier permeability was greater in the aging spinal cord compared with aging brain; this was associated with increased tissue cytokine levels. Aged microglia had deficits in phagocytosis at baseline and after stimulus-induced activation. The identification of age-specific, high scatter microglia together with the use of ex-vivo functional analyses provides the first functional characterization of senescent microglia. Age and regional-specificity of CNS disease should be taken into consideration when developing immune-modulatory treatments.

Cardiac sarcoidosis and coronary artery disease: a two-hit mechanism to left ventricular dysfunction (or is it)?

This report describes a case of cardiac sarcoidosis in a 40-year-old man with minimal risk factors for coronary artery disease who was found to have a critical coronary lesion on angiography performed for declining left ventricular function. The case highlights the diagnostic and therapeutic issues surrounding cardiac sarcoidosis and raises the question of a possible link between sarcoidosis and premature coronary artery disease. It also stresses the importance of ruling out ischemia in any patient with declining left ventricular function.

Microglia and ischemic stroke: a double-edged sword

Inflammatory processes have a fundamental role in the pathophysiology of stroke. A key initial event is the rapid activation of resident immune cells, primarily microglia. This cell population is an important target for new therapeutic approaches to limit stroke damage. Activation of microglia is normally held in check by strictly controlled mechanisms involving neuronal-glial communication. Ischemic stroke is a powerful stimulus that disables the endogenous inhibitory signaling and triggers microglial activation. Once activated, microglia exhibit a spectrum of phenotypes, release both pro- and anti-inflammatory mediators, and function to either exacerbate ischemic injury or help repair depending on different molecular signals the microglial receptors receive. Various ligands and receptors have been identified for microglial activation. Experimental tools to detect these inflammatory signals are being increasingly developed in an effort to define the functional roles of microglia. Fine-tuning immunomodulatory interventions based on the heterogeneous profiles of microglia are urgently needed for ischemic stroke.

Evaluation of two resin based fissure sealants: a comparative clinical study

OBJECTIVE

To evaluate retention of two resin based fissure sealants (Embrace and Delton FS+) for a period of twelve months.

MATERIALS AND METHODS

Sixty eight first permanent molars were sealed for seventeen healthy children in the age group of six-eight years. According to random selection, the first permanent molars on the right side of both arches were sealed with Embrace (Group A) and on the left side of both arches were sealed with Delton FS+ (Group B).

RESULTS

The total retention of Embrace was 23.50% and for Delton FS+ was 17.60% at one year.

CONCLUSION

At one year the total retention of Embrace was 23.50% and for Delton FS+ was 17.60%, however the results were statistically insignificant.

Persistence and dissipation kinetics of deltamethrin on chili in different agro-climatic zones of India

Multi-location supervised field trials were conducted at four different agro climatic locations in India to evaluate the dissipation pattern of deltamethrin on chili. Deltamethrin 10 EC was applied on chili @17.5 and 35 g a.i. ha(-1), samples of green chili were drawn at different time intervals and that of red chili and soil at harvest time and quantified by gas liquid chromatography equipped with electron capture detector. The identity of residues were confirmed by Gas Chromatograph-Mass Spectrophotometer in selective ion monitoring mode in mass range 181, 253 m/z. Limit of quantification of the method was found to be 0.01 mg kg(-1). Half-life of deltamethrin at application rate of 17.5 g a.i. ha(-1) varied from 0.36 to 1.99 days and at double the application rate was found to range from 0.38 to 2.06 days. Residues of deltamethrin were found below its determination limit of 0.01 mg kg(-1) in red chili and soil. On the basis of the data generated, Deltamethrin 10 EC has been registered for use on chili in India and its Maximum Residue Limit has been fixed as 0.05 μg/g.

Parasagittal biopsies are more important as part of an initial biopsy strategy than as part of a repeat biopsy strategy: observations from a unique population

Comparing the yield of parasagittal biopsies during initial saturation biopsy to the yield during repeat saturation biopsy for detection of prostate cancer. Office-based saturation biopsy (24 cores) with periprostatic lidocaine block was performed in 139 consecutive men who had never previously undergone prostate biopsy. Indication for biopsy was elevated prostate-specific antigen >2.5 ng/dl. Biopsy specimens were obtained and marked by location for histological examination. Subanalysis of patients from this unique study was performed to compare the location of saturation biopsy cancer detection in these patients to a cohort of 100 patients who had previously undergone biopsy with nonmalignant findings. In the initial biopsy group, cancer was detected in 62/139 patients (44.6%). Breakdown of cancer location demonstrated unique parasagittal cancers in 9/62 patients (14.5%). Laterally base cancer was found exclusively in 22/62 patients (35.5%). For the repeat biopsy population, cancer was found in 25 patients (25%); no patients (0%) had exclusive parasagittal cancer. To our knowledge, this is the first study to demonstrate a difference in the location of positive cores between initial and repeat biopsy status. The exclusive parasagittal cancer detection rate decreases significantly in the repeat biopsy population when using the same biopsy method. Our findings support including traditional template parasagittal sampling of the prostate on first-time biopsy in addition to lateral cores typical of extended field biopsies for a total of 10-12 cores. However, parasagittal sampling adds negligible additional information in repeat biopsy; thus we recommend obtaining primarily laterally based cores for repeat biopsy.

Nanotechnology and pharmaceutical inhalation aerosols

Pharmaceutical inhalation aerosols have been playing a crucial role in the health and well being of millions of people throughout the world for many years. The technology's continual advancement, the ease of use and the more desirable pulmonary-rather-than-needle delivery for systemic drugs has increased the attraction for the pharmaceutical aerosol in recent years. But administration of drugs by the pulmonary route is technically challenging because oral deposition can be high, and variations in inhalation technique can affect the quantity of drug delivered to the lungs. Recent advances in nanotechnology, particularly drug delivery field have encouraged formulation scientists to expand their reach in solving tricky problems related to drug delivery. Moreover, application of nanotechnology to aerosol science has opened up a new category of pharmaceutical aerosols (collectively known as nanoenabled-aerosols) with added advantages and effectiveness. In this review, some of the latest approaches of nano-enabled aerosol drug delivery system (including nano-suspension, trojan particles, bioadhesive nanoparticles and smart particle aerosols) that can be employed successfully to overcome problems of conventional aerosol systems have been introduced.

Low levels of high-density lipoprotein cholesterol are associated with vascular remodeling in cardiac transplant recipients

BACKGROUND

Early atherosclerosis may be associated with compensatory vessel enlargement, termed positive remodeling. Enlarged brachial artery diameter has been reported in patients with risk factors for atherosclerosis and in individuals with coronary atherosclerosis, indicating that brachial artery enlargement is a marker for the presence of atherosclerotic changes. Cardiac transplant recipients often have abnormal lipid levels, but the effect of specific lipid abnormalities on vascular remodeling in this population has not been evaluated. This study examined the relationship between lipid levels and brachial artery diameter in cardiac transplant recipients.

METHODS

Thirty-five stable cardiac transplant recipients underwent high-resolution brachial artery ultrasound to evaluate resting brachial artery diameter. Levels of high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides were determined and the presence of other cardiac risk factors was assessed.

RESULTS

Brachial artery diameter was larger (4.3 +/- 0.1 mm) in subjects with low levels of HDL-C (< 40 mg/dL, n = 11) compared to subjects with high HDL-C (> or = 40 mg/dL, n = 24), who had a mean brachial artery diameter of 3.7 +/- 0.1 mm (P = .006). Neither high LDL-C (> or = 100 mg/dL) nor high triglycerides (> or = 200 mg/dL) were associated with differences in brachial artery diameter. Multivariate analysis demonstrated that the relationship between low HDL-C and increased brachial artery diameter was independent of body surface area or statin use.

CONCLUSIONS

Low levels of HDL-C are an independent predictor of brachial artery enlargement in stable cardiac transplant recipients. These findings suggest that suboptimal HDL-C levels may be associated with the development of vascular remodeling and atherosclerosis in this population.

Noninvasive testing for coronary artery disease in women

Coronary artery disease is a major cause of morbidity and mortality for women in North America and Europe. Given the significance of coronary disease as a public health problem among women, accurate diagnosis of this condition is of great importance. Several noninvasive testing modalities are available for the diagnosis of coronary heart disease. An understanding of gender-based differences related to noninvasive cardiac testing is useful in order to optimally utilize these tests and improve detection and clinical outcomes in women.

The relationship between alcohol and head injury and its effect on the conscious level

The incidence of head injury has risen in recent years and now accounts for almost one-third of acute male surgical admissions to the Western Infirmary, Glasgow. A prospective study has established that in Glasgow alcohol is a major associated factor, 62 per cent of males and 27 per cent of females having detectable levels in the blood (&gt; 5 mg/100 ml); in these patients the mean level was 193 mg/100 ml in men and 165 mg/100ml in women. The alcohol level was significantly higher in patients who had had ‘a fall under the influence’, or had been the victims of assault, than in those involved in traffic or other accidents. This suggests that alcohol may be an important contributory cause of head injuries in this city. Depression of the conscious level occurred at blood alcohol levels around 200 mg/ 100 ml, but a significant number of patients in coma had a serious head injury.

The entorhinal cortex in first-episode psychotic disorders: a structural magnetic resonance imaging study

OBJECTIVE

Neuropathological findings regarding the entorhinal cortex in schizophrenia are conflicting. The authors used structural magnetic resonance imaging to examine the entorhinal cortex volumes of healthy subjects and medication-naive patients experiencing their first episode of psychotic illness.

METHOD

The study included 33 patients with schizophrenia and related disorders, 11 patients with nonschizophrenic disorders, and 43 matched healthy subjects. All subjects were rated on the Scale for the Assessment of Positive Symptoms and the Scale for the Assessment of Negative Symptoms, and volumetric measurements of the entorhinal cortex were obtained for all subjects. The authors examined differences across the groups as well as clinical correlations of entorhinal cortex volumes adjusted for intracranial volume.

RESULTS

A significant diagnosis effect was seen in the left entorhinal cortex: patients with schizophrenia and related disorders and patients with nonschizophrenic psychotic disorders had smaller left entorhinal cortex volumes than healthy subjects. The mean entorhinal cortex volume of patients with schizophrenic disorders did not differ from that of patients with nonschizophrenic psychotic disorders. In patients with schizophrenic disorders, the entorhinal cortex volume positively correlated with severity of delusions. The mean entorhinal cortex volume of patients with nondelusional psychotic disorders was significantly smaller than that of patients with delusional psychotic disorders and healthy subjects.

CONCLUSIONS

Smaller entorhinal cortex volume in first-episode, neuroleptic-naive psychotic disorders may not be a confound of the effects of illness chronicity or antipsychotic treatment. Entorhinal cortex pathology appears to have a significant association with positive symptoms, specifically delusions. The impairment of functions in which the entorhinal cortex participates-such as novelty detection, associative learning, and processing episodic, recognition, and autobiographical memory-could be responsible for its association with psychotic disorders and delusions.

Bupivacaine provides rapid, effective periprostatic anaesthesia for transrectal prostate biopsy

OBJECTIVE

To examine the effectiveness of the longer acting agent bupivacaine in providing periprostatic anaesthesia during transrectal ultrasonography (TRUS)-guided biopsy, as the periprostatic injection of lidocaine has been shown to significantly alleviate the pain of this procedure.

PATIENTS AND METHODS

Seventy-five patients were randomized to receive a periprostatic injection with either bupivacaine, a lidocaine/bupivacaine (1/1) combination, or no local anaesthesia. Immediately before biopsy 5 mL of the anaesthetic was injected under TRUS guidance into the periprostatic nerves bilaterally. After taking a 10-core biopsy the patients were given a visual analogue scale (VAS; 0-10) to assess their pain during the procedure.

RESULTS

The mean VAS scores were 2.04 in the bupivacaine group and 4.46 in the control (no local anaesthetic) group (P < 0.001).

CONCLUSIONS

Bupivicaine provides significant, immediate periprostatic anaesthesia for TRUS biopsy.

Peripheral vascular endothelial function testing as a noninvasive indicator of coronary artery disease

OBJECTIVES

We studied whether assessment of endothelium-dependent vasomotion (EDV) with brachial artery ultrasound (BAUS) imaging predicts the presence or absence of coronary artery disease (CAD) as defined by exercise myocardial perfusion imaging (ExMPI).

BACKGROUND

Abnormalities in EDV can be detected in arteries before the development of overt atherosclerosis, and its presence may predict poor long-term prognosis. Brachial artery ultrasound during reactive hyperemia is a noninvasive method of assessing peripheral EDV.

METHODS

Clinically-indicated ExMPI along with BAUS were performed in 94 subjects (43 women, 51 men). Coronary artery disease was defined by myocardial ischemia or infarction on single photon emission computed tomography images. Flow-mediated dilation (FMD) after upper arm occlusion was defined as the percent change in arterial diameter during reactive hyperemia relative to the baseline.

RESULTS

Subjects with CAD by ExMPI (n = 23) had a lower FMD (6.3 +/- 0.7%) than those without CAD by ExMPI (n = 71) (10.5 +/- 0.6%; p = 0.0004). Flow-mediated dilation was highly predictive for CAD with an odds ratio of 1.32 for each percent decrease in FMD (p = 0.001). Based on a receiver-operator analysis, an FMD of 10% was used as a cut-point for further analysis. Twenty-one of 23 subjects who were positive for ExMPI had an FMD < 10% (sensitivity 91%), whereas only two of 40 subjects with an FMD > or =10% were ExMPI-positive (negative predictive value: 95%). There was a correlation between the number of cardiac risk factors and FMD. Individuals with an FMD < 10% exercised for a shorter duration than those with an FMD > or =10% (456 +/- 24 vs. 544 +/- 31 s, respectively; p = 0.02).

CONCLUSIONS

Assessment of EDV with BAUS has a high sensitivity and an excellent negative predictive value for CAD and, thus, has the potential for use as a screening tool to exclude CAD in low-risk subjects. Further standardization of BAUS is required, however, before specific cut-points for excluding CAD can be established.

Lower body negative pressure: a test of cardiovascular autonomic function

Lower body negative pressure (LBNP) may provide an alternative test of cardiovascular autonomic function for patients unable to perform the Valsalva maneuver (VM). LBNP at -40 mmHg for 30 s was compared to the VM at 40 mmHg for 15 s with heart rate and blood pressure measured continuously in three age groups: 10-25 years; 26-40 years; and 41-55 years. Heart rate and blood pressure responses were comparable, with moderately diminished changes in blood pressure and heart rate in the LBNP test. When heart response to LBNP was converted to a ratio similar to that calculated for the VM, a high degree of correlation was found (R(2) = 0.5711). The LBNP test shows promise as an alternative test of cardiovascular autonomic function based on studies in normal subjects. The less marked changes may relate to the more passive nature of the applied stress. Future work should improve the device's accessibility and establish values for patients with autonomic disorders.

Role of tensile stress and strain in the induction of cell death in experimental vein grafts

Tensile stress and strain are known to induce vascular cell proliferation, a process that is physiologically counterbalanced by cell death. Here we investigate whether tensile stress and strain regulate vascular-cell death by using an end-to-end anastomosed rat vein graft model. In such a model, the circumferential tensile stress in the graft wall was increased by approximately 140 times immediately after surgery compared with that in the venous wall. This change was associated with an increase in the percentage of TUNEL-positive cells at 1, 6, 24, 120, 240, and 720h with two distinct peaks at 1 and 24h (10.1+/-3.5 and 14.4+/-3.2%, respectively) compared with that in control jugular veins (0.4+/-0.5 and 0.5+/-0.5% at 1 and 24h, respectively). When tensile stress and strain in the vein graft wall were reduced by using a biomechanical engineering approach, the rate of cell death was reduced significantly (3.6+/-1.1 and 1.6+/-0.5% at 1 and 24h, respectively). Furthermore, DEVD-CHO, a tetrapeptide aldehyde that inhibits the activity of caspase 3, significantly suppressed this event. These results suggest that a step increase in tensile stress and strain in experimental vein grafts induces rapid cell death, which is possibly mediated by cell death signaling mechanisms.

Heart failure etiology affects peripheral vascular endothelial function after cardiac transplantation

OBJECTIVES

The goal of this study was to examine the effect of heart failure etiology on peripheral vascular endothelial function in cardiac transplant recipients.

BACKGROUND

Peripheral vascular endothelial dysfunction occurs in patients with heart failure of either ischemic or nonischemic etiology. The effect of heart failure etiology on peripheral endothelial function after cardiac transplantation is unknown.

METHODS

Using brachial artery ultrasound, endothelium-dependent, flow-mediated dilation (FMD) was assessed in patients with heart failure with either nonischemic cardiomyopathy (n = 10) or ischemic cardiomyopathy (n = 7), cardiac transplant recipients with prior nonischemic cardiomyopathy (n = 10) or prior ischemic cardiomyopathy (n = 10) and normal controls (n = 10).

RESULTS

Patients with heart failure with either ischemic cardiomyopathy or nonischemic cardiomyopathy had impaired FMD (3.6 +/- 1.0% and 5.1 +/- 1.2%, respectively, p = NS) compared with normal subjects (13.9 +/- 1.3%, p < 0.01 compared with either heart failure group). In transplant recipients with antecedent nonischemic cardiomyopathy, FMD was markedly higher than that of heart failure patients with nonischemic cardiomyopathy (13.0 +/- 2.4%, p < 0.001) and similar to that of normal subjects (p = NS). However, FMD remained impaired in transplant recipients with prior ischemic cardiomyopathy (5.5 +/- 1.5%, p = 0.001 compared with normal, p = 0.002 vs. transplant recipients with previous nonischemic cardiomyopathy).

CONCLUSIONS

Peripheral vascular endothelial function is normal in cardiac transplant recipients with antecedent nonischemic cardiomyopathy, but remains impaired in those with prior ischemic cardiomyopathy. In contrast, endothelial function is uniformly abnormal for patients with heart failure, regardless of etiology. These findings indicate that cardiac transplantation corrects peripheral endothelial function for patients without ischemic heart disease, but not in those with prior atherosclerotic coronary disease.

Mitral regurgitation: comprehensive assessment by echocardiography

Two-dimensional and Doppler echocardiography have become the major modalities for the assessment of mitral regurgitation. The combined use of these techniques provides information regarding the morphology of the valvular apparatus as well as the severity of regurgitation. Transesophageal and three-dimensional echocardiography provide a more-detailed evaluation of valve morphology, which can be valuable in determining suitability for valve repair. In patients with severe mitral regurgitation, echocardiographic assessment of ventricular size and function plays a critical role in determining the optimal timing of surgery.

Intraoperative transesophageal echocardiography: correlation of echocardiographic findings and surgical pathology

Before the introduction of transesophageal echocardiography (TEE) in the operating room, intraoperative echocardiography relied on epicardial imaging. The disadvantages of this approach included interference with the surgical procedure, limited windows, and potential distortion of cardiac structures. Consequently, multiplane TEE has now emerged as the intraoperative imaging method of choice. It provides high-resolution images of cardiac structures and excellent portraits of flow abnormalities. Intraoperative TEE does not interfere with the surgical field and procedure. TEE provides better imaging of the valves, atria, aorta, pulmonic vasculature, and pericardium, which are sometimes difficult to visualize by transthoracic echocardiography. TEE is especially beneficial in surgeries for valve replacement, valve repair, cardiac mass, aortic disease, congenital heart disease, and pericardial disease. Presurgical TEE provides information for surgical planning. TEE is helpful for the assessment of the immediate result of surgery and detection of complications that may need a prompt response. Thus, intraoperative TEE has a vital impact on management of cardiac surgery.

Polyamine depletion is associated with an increase in JunD/AP-1 activity in small intestinal crypt cells

Activator protein 1 (AP-1) is a group of dimeric transcription factors composed of protooncogene (Jun and Fos) subunits that bind to a common DNA site, the AP-1 binding site. The proteins of c-Jun, JunB, and Fos are essential for initiation of the cell cycle. Conversely, the activation of the junD gene slows cell growth in some cell types. The current study tests the hypothesis that polyamines influence cell growth by altering the balance of positive and negative Jun/AP-1 activities in intestinal epithelial cells. Studies were conducted in the IEC-6 cell line derived from rat small intestinal crypt cells. Administration of alpha-difluoromethylornithine (DFMO), a specific inhibitor for polyamine synthesis, for 4 and 6 days completely depleted cellular polyamine levels, while AP-1 binding activity was significantly increased. Spermidine, when given together with DFMO, restored AP-1 binding activity toward normal. The increased AP-1 complexes in polyamine-deficient cells were dramatically supershifted by the anti-JunD antibody but not by antibodies against c-Jun, JunB, or Fos proteins. There were significant increases in JunD mRNA and protein in DFMO-treated cells, although expression of the c-fos, c-jun, and junB genes decreased. The increase in JunD/AP-1 activity in DFMO-treated cells was associated with a significant decrease in cell division. Exposure of control quiescent cells to 5% dialyzed serum increased c-Jun/AP-1 but not JunD/AP-1 activities. DFMO prevented the stimulation of c-Jun/AP-1 activity induced by 5% dialyzed serum. These results indicate that 1) polyamine depletion is associated with an increase in AP-1 binding activity and 2) the increase in AP-1 activity in the DFMO-treated cells was primarily contributed by an increase in the JunD/AP-1. These findings suggest that polyamines regulate cell growth at least partially by modulating the balance of positive and negative Jun/AP-1 activities in the intestinal mucosa.

Expression of the transforming growth factor-beta gene during growth inhibition following polyamine depletion

Polyamine depletion and cytokine transforming growth factor-beta (TGF-beta) inhibit cell proliferation. The current study tests the hypothesis that polyamine depletion results in growth inhibition by altering expression of the TGF-beta gene in intestinal epithelial cells. Studies were conducted in the IEC-6 cell line derived from rat small intestinal crypt cells. Cells were grown in DMEM in the presence or absence of alpha-difluoromethylornithine (DFMO), a specific inhibitor of polyamine biosynthesis, for 6 and 12 days. Administration of DFMO not only depleted intracellular polyamines but also significantly increased the mRNA levels of TGF-beta. Increased TGF-beta mRNA in DFMO-treated cells was paralleled by an increase in TGF-beta content. Depletion of intracellular polyamines by DFMO had no effect on the rate of TGF-beta gene transcription, as measured by nuclear run-on assay. The half-life of mRNA for TGF-beta in normal cells was approximately 65 min and increased to >16 h in cells treated with DFMO for 6 or 12 days. Exogenous polyamine, when given together with DFMO, prevented the increased half-life of TGF-beta mRNA in IEC-6 cells. TGF-beta added to the culture medium significantly decreased the rate of DNA synthesis and final cell number in normal and polyamine-deficient cells. Furthermore, growth inhibition caused by polyamine depletion was partially but significantly blocked by addition of immunoneutralizing anti-TGF-beta antibody. These results indicate that 1) depletion of intracellular polyamines induces the activation of the TGF-beta gene through posttranscriptional regulation and 2) increased expression of the TGF-beta gene plays an important role in the process of growth inhibition following polyamine depletion.

Echocardiographic analysis of regional and global left ventricular shape in Chagas' cardiomyopathy

Chagas' heart disease is a common form of cardiomyopathy in Latin America and an important cause of cardiac morbidity and mortality there. Left ventricular (LV) apical aneurysm and LV dysfunction are frequent findings in Chagas' cardiomyopathy. Because cardiac shape has important implications for LV function, we sought to characterize regional and global changes in LV geometry in Chagas' heart disease. Quantitative shape analysis was performed on 2-dimensional echocardiograms from 43 patients with Chagas' cardiomyopathy. Regional shape was quantitated by measuring endocardial curvature and global shape was evaluated by Fourier shape analysis of the endocardial contour. Data from 22 age- and sex-matched normal test subjects were used for comparison. Regional shape analysis demonstrated decreased apical curvature (consistent with blunting of normal apical shape) in the group with Chagas' disease compared with controls (apical 2-chamber view: 19 +/- 1 vs 24 +/- 1 [p = 0.0039] at end-diastole and 20 +/- 2 vs 29 +/- 3 [p = 0.0019] at end-systole). Fourier shape power index was decreased in the Chagas' group, consistent with a more spherical ventricle (apical 2-chamber view: 9 +/- 1 vs 17 +/- 2 [p <0.0001] at end-diastole and 12 +/- 1 vs 35 +/- 3 [p <0.0001] at end-systole). Shape changes among the population with Chagas' disease were further evaluated in those with end-diastolic volumes equal to or greater than the median for the group (104 ml) and those < 104 ml. Global shape did not differ between patients with dilated ventricles and those with relatively nondilated ventricles. Diastolic Fourier shape power index = 8 +/- 2 in dilated ventricles compared with 9 +/- 5 in nondilated ventricles (p = 0.53); systolic Fourier shape power index = 10 +/- 2 in dilated versus 14 +/- 2 in nondilated ventricles (p = 0.15) (apical 2-chamber view). In Chagas' cardiomyopathy, LV apical deformation results in disruption of the optimal global prolate-ellipsoid shape, even in patients with relatively preserved LV volumes.

Synergistic induction of ornithine decarboxylase by asparagine and gut peptides in intestinal crypt cells

The objective of this study was to determine whether the amino acid asparagine stimulated the activity of ornithine decarboxylase (ODC) synergistically with epidermal growth factor (EGF) or gastrin in IEC-6 cells, a line of normal rat small intestinal crypt cells. Cells were grown in DMEM containing 5% dialyzed fetal bovine serum, and serum was deprived for 24 h before experiments. Exposure to EGF or gastrin alone increased ODC activity 4.5- to 6-fold. Asparagine alone increased the enzyme activity 10- to 13-fold in IEC-6 cells. Simultaneous addition of asparagine and EGF or gastrin, however, increased ODC activity more than 40-fold. In contrast, there was no synergistic induction of ODC activity when gastrin and EGF were added together. Increased ODC activity in cells treated with asparagine and EGF or gastrin was associated with an increase in ODC mRNA and protein levels. The rate of transcription of the ODC gene was significantly increased by exposure to EGF or gastrin. Asparagine alone had little or no effect on the rate of transcription of the ODC gene. When given together with EGF or gastrin, asparagine also had no additional effect on the transcription rate of the ODC gene. The half-life of mRNA for ODC in unstimulated IEC-6 cells was approximately 30 min and increased to more than 2 h in cells exposed to asparagine, although neither gastrin nor EGF prolonged the stability of ODC mRNA. The half-life of mRNA for ODC after combined addition of asparagine and EGF or gastrin was extended to approximately 2 h, similar to asparagine alone. Combined addition of asparagine and EGF or gastrin also significantly increased DNA synthesis compared with cells exposed to each of the three agents alone. In conclusion, 1) simultaneous addition of asparagine and EGF or gastrin increases ODC activity in a synergistic manner and 2) asparagine increases ODC mRNA levels through completely distinct mechanisms from EGF or gastrin. EGF or gastrin specifically stimulates transcription of the ODC gene, whereas asparagine affects a posttranscriptional process.

Differences in transglutaminase mRNA after polyamine depletion in two cell lines

Polyamines serve as natural substrates for the transglutaminase that catalyzes covalent cross-linking of proteins and is involved in cellular adhesion and proliferation. This study tests the hypothesis that intracellular polyamines play a role in the regulation of transglutaminase expression in rat small intestinal crypt cells (IEC-6 cell line) and human colon carcinoma cells (Caco-2 cell line). Treatment with alpha-difluoromethylornithine (DFMO; a specific inhibitor of polyamine synthesis) significantly depleted the cellular polyamines putrescine, spermidine, and spermine in both cell lines. In IEC-6 cells, polyamine depletion was associated with a decrease in the levels of transglutaminase mRNA. In Caco-2 cells, however, polyamine depletion significantly increased the levels of transglutaminase mRNA and enzyme activity. In both cell lines, ornithine decarboxylase mRNA levels increased and protooncogene c-myc mRNA decreased in the presence of DFMO. Addition of polyamines to cells treated with DFMO reversed the effect of DFMO on the levels of mRNA for these genes in both lines. There was no significant change in the stability of transglutaminase mRNA between control and DFMO-treated IEC-6 cells. In contrast, the half-life of mRNA for transglutaminase in Caco-2 cells was dramatically increased after polyamine depletion. Spermidine, when given together with DFMO, completely prevented increased half-life of transglutaminase mRNA in Caco-2 cells. These results indicate that 1) expression of transglutaminase requires polyamines in IEC-6 cells but is inhibited by these agents in Caco-2 cells, 2) polyamines modulate transglutaminase expression at the level of mRNA through different pathways in these two cell lines, and 3) posttranscriptional regulation plays a major role in the induction of transglutaminase mRNA in polyamine-deficient Caco-2 cells.

Polyamines modulate transcription but not posttranscription of c-myc and c-jun in IEC-6 cells

The goal of the current study was to examine whether polyamines are involved in the regulation of transcription and posttranscription of the protooncogenes c-myc and c-jun in intestinal epithelial cells. Studies were conducted in the IEC-6 cell line derived from rat small intestinal crypt cells. Administration of alpha-difluoromethylornithine (DFMO), a specific inhibitor of polyamine synthesis, for 4 or 6 days not only almost completely depleted total (whole) cellular and nuclear polyamines but also significantly decreased expression of the protooncogenes c-myc and c-jun in IEC-6 cells. Using nuclear run-on transcription assay, we demonstrated that the basal rate of transcription of c-myc was decreased by 55% at 4 days and by 60% at 6 days in the DFMO-treated cells. The c-jun transcription in DFMO-treated cells was decreased by 75% at 4 days and 85% at 6 days. The transcription rates of c-myc and c-jun were dramatically stimulated by 5% dialyzed fetal bovine serum (dFBS) in normal quiescent cells. However, polyamine depletion significantly prevented the increased transcription of these two genes in the DFMO-treated cells exposed to 5% dFBS. Furthermore, direct administration of spermidine to isolated nuclei from polyamine-deficient (caused by DFMO) cells resulted in a 2- to 2.5-fold increase in c-myc and c-jun transcription. There were no significant changes in the half-lives of c-myc and c-jun mRNAs between the controls and the DFMO-treated cells. These results indicate that 1) polyamines are required for the transcription of the protooncogenes c-myc and c-jun in IEC-6 cells and 2) depletion of intracellular polyamines has no effect on posttranscriptional regulation of c-myc and c-jun mRNAs. These findings suggest that polyamines play an important role in the regulation of the transcription of protooncogenes, and this may be one mechanism by which polyamines modulate mucosal cell division.

Pressure natriuresis after adrenomedullin in anesthetized spontaneously hypertensive rats

Adrenomedullin (ADM), a peptide with potent vasodilatory and natriuretic actions, is elevated in patients with essential hypertension. Because pharmacological doses of ADM result in renal vasodilation and natriuresis, it has been suggested that ADM may play a modulatory role in hypertension through potential actions on renal pressure natriuresis. However, it is unclear whether elevation of plasma ADM within the pathophysiological range has similar actions. To determine the effects of pathophysiological doses of ADM on blood pressure and on the relationship between renal perfusion pressure (RPP) and renal hemodynamics and sodium excretion, renal function was determined at RPPs of 80, 105, 130, and 155 mm Hg in spontaneously hypertensive rats (SHR) infused with ADM at 50 ng x kg(-1) x min(-1) (ADM-50, n=5) and at 100 ng x kg(-1) x min(-1) (ADM-100, n=5) and in control SHR (n=5). Decreasing RPP from 155 to 80 mm Hg in control SHR decreased (P<.05) absolute sodium excretion from 0.81+/-0.25 to 0.04+/-0.02 microEq/min, fractional sodium excretion from 0.32+/-0.11% to 0.06+/-0.04%, and urine flow rate from 11.5+/-2.8 to 1.03+/-0.31 microL/min. ADM infusion elevated (P<.05) plasma ADM levels in ADM-infused SHR (679+/-47 pg/mL in ADM-50, 858+/-79 in ADM-100) compared with control (79.5+/-27.8). However, although reduction of RPP from 155 to 80 mm Hg in ADM rats decreased absolute sodium excretion (ADM-50, 0.98+/-0.10 to 0.09+/-0.04 microEq/min; ADM-100, 0.95+/-0.09 to 0.07+/-0.02 microEq/min), fractional sodium excretion (ADM-50, 0.31+/-0.03% to 0.17+/-0.04%; ADM-100, 0.33+/-0.02% to 0.09+/-0.01%), and urine flow (ADM-50, 13.6+/-1.4 to 1.73+/-0.75 microL/min; ADM-100, 13.5+/-1.5 to 1.07+/-0.16 microL/min), these decreases were not different from values found in controls. Renal plasma flow and glomerular filtration rate were also similar in control and ADM-treated SHR at each level of RPP. Thus, acute increases in ADM to levels found in pathophysiological conditions have no effect on blood pressure, pressure natriuresis, or renal autoregulation in the SHR. These findings do not support the hypothesis that ADM serves as a modulating factor in hypertension, at least in the SHR.

Right ventricular dilation in primary amyloidosis: an independent predictor of survival

This study was designed to characterize the geometry and function of the right ventricle and its prognostic significance in patients with primary (AL) cardiac amyloidosis. AL amyloidosis is an infiltrative systemic disease that can result in thickening of heart structures and rapidly progressive congestive heart failure due to restrictive ventricular physiology and eventual systolic dysfunction. Thirty-seven patients with AL amyloid heart involvement and 20 normal control subjects were evaluated using 2-dimensional and Doppler echocardiography. Based on the ratio of left-to-right end-diastolic ventricular chamber areas, patients were classified into 2 groups: 25 patients with disproportionate right ventricular (RV) dilation (left ventricular to RV ratio < or = 2) and 12 with a ventricular area ratio > 2. Patients with a relatively dilated right ventricle (ratio < or = 2) had a shorter median survival (4 months) compared with patients with an area ratio > 2 (10 months, p <0.003). Of multiple clinical, echocardiographic, and Doppler features entered into a multifactorial model, a ventricular area ratio < or = 2 remained the only independent predictor of survival. Patients with AL amyloid heart disease represent a heterogeneous population with regard to both prognosis and the relative degree of right to left ventricular dilation. RV dilation in patients with amyloid heart disease appears to be associated with more severe involvement and is associated with a very poor prognosis with a median survival of only 4 months.

Nitric oxide, the kidney and hypertension

1. According to the renal body fluid feedback mechanism for long-term control, persistent hypertension can only occur as a result of a reduction in renal sodium excretory function or a hypertensive shift in the pressure natriuresis relationship. Although an abnormal relationship between renal perfusion pressure and renal sodium excretion has been identified in every type of hypertension where it has been sought, factors responsible for this effect are still unclear. 2. Nitric oxide (NO) is produced within the kidney and plays an important role in the control of many intrarenal processes that regulate the renal response to changes in perfusion pressure and, thus, help determine systemic vascular volume and blood pressure. Numerous studies have shown that long-term inhibition of NO synthesis results in a chronic hypertensive shift in renal pressure natriuresis. 3. Recent studies have shown that certain animal models of genetic hypertension and forms of human hypertension areas are associated with a decrease in NO synthesis. Reductions in NO synthesis reduce renal sodium excretory function, not only through direct action on the renal vasculature, but through modulation of other vasoconstrictor processes and through direct and indirect alterations in tubular sodium transport. 4. The causes and consequences of the disregulation of NO in hypertension and other renal disease processes remain an important area of investigation.

Red cell aplasia caused by parvovirus B19 in AIDS: use of i.v. immunoglobulin

We describe the case of a 34-year-old man with AIDS who developed severe anemia due to chronic pure red cell aplasia (PRCA) caused by parvovirus B19. Following initial treatment with an infusion of intravenous immunoglobulin (IVIg), 1 g/kg, PRCA resolved, but there was a recurrence of severe anemia in 3 months. Retreatment with 2 g/kg IVIg over 2 days resulted in normalization of hemoglobin and a significantly longer remission duration. Two doses of 0.4 g/kg IVIg q 4 wk failed to prevent a relapse of PRCA in our patient. The dose and schedule of IVIg in the treatment of PRCA caused by parvovirus B19 in AIDS requires further definition.

Chronic sodium-potassium-ATPase inhibition with ouabain impairs renal haemodynamics and pressure natriuresis in the rat

1. Chronic Na+, K(+)-ATPase inhibition with ouabain induces hypertension in the rat. To examine the role of the kidney in this process, the effect of changes in renal perfusion pressure on glomerular filtration rate, renal blood flow and urinary sodium excretion were determined in rats treated intraperitoneally with ouabain (27.8 micrograms day-1 kg-1 body weight) or vehicle for 6 weeks. 2. After ouabain administration, baseline mean arterial pressure was significantly higher (P < 0.05) in ouabain-treated rats (151 +/- 2 mmHg; n = 9) than in control rats (116 +/- 4 mmHg; n = 8). 3. At equivalent renal perfusion pressures, glomerular filtration rate was significantly lower (P < 0.05) in ouabain-treated rats compared with control rats. Glomerular filtration rate was 721 +/- 73 microliters/min at 150 mmHg, and fell significantly to 322 +/- 64 microliters/min at 100 mmHg. In the control group, glomerular filtration rate was well autoregulated. The glomerular filtration rate autoregulatory index was calculated to determine the ability to maintain glomerular filtration rate during changes in renal perfusion pressure (0 reflects perfect autoregulation; > 1 reflects the absence of autoregulation). This index was greater in the ouabain group than in the control group (1.54 +/- 0.2 compared with 0.29 +/- 0.2; P < 0.05). Renal blood flow showed a similar pattern. 4. Absolute urinary sodium excretion rate was less in ouabain-treated rats than in control rats at equivalent renal perfusion pressures. The slope of the relationship between absolute urinary sodium excretion rate and renal perfusion pressure was greater (P < 0.05) in the control group than in the ouabain group (309.1 +/- 57.1 compared with 82.1 +/- 14.8 mumol min-1 mmHg-1). 5. Thus, chronic inhibition of Na+,K(+)-ATPase induces less efficient autoregulation of glomerular filtration rate and renal blood flow as well as a rightward shift in the pressure natriuresis relationship, such that a 25-30 mmHg higher renal perfusion pressure is necessary to excrete any given sodium load. These abnormalities may contribute to the development and maintenance of hypertension in this model.

The effect of carbon dioxide laser on acid resistance of human tooth enamel: an evaluation by wet chemical analysis and scanning electron microscopy

The use of the laser in improving acid resistance of tooth enamel has captured the imagination of most researchers. Man's susceptibility to dental caries presents itself as one of the most complicated problems to solve. The carbon dioxide laser at a wavelength of 10.6 microns is highly efficient for dental purposes as this wavelength is close to optimum absorption of dental enamel. A study was carried out using a pulsed carbon dioxide laser to find the effects of laser beam on human tooth enamel in an energy range of 2-20 J/cm2 at a pulse rate of 5 Hz. The effective resistance to acid was determined by wet chemical analysis whereas superficial changes seen on the surface were determined using the scanning electron microscope.

Acute Na+,K+-ATPase inhibition with bufalin impairs pressure natriuresis in the rat

Although it has been reported that Na+,K+-ATPase inhibition with bufalin induces acute and chronic hypertension in the rat, the mechanisms mediating this response are unclear. To examine the role of the kidney in this process, glomerular filtration rate, renal blood flow, and pressure natriuresis were determined in rats treated with bufalin or vehicle during changes in renal perfusion pressure. Mean arterial pressure increased from 123 +/- 4 to 149 +/- 3 mm Hg (P < .05) after 40 minutes of intravenous bufalin and remained at this level. In control rats, glomerular filtration rate was well autoregulated. In bufalin-treated rats, glomerular filtration rate fell with decreasing renal perfusion pressure. Glomerular filtration rate autoregulatory index was greater in bufalin-treated than control rats (P < .05). Renal blood flow showed a similar pattern. Urine flow and sodium excretion were less in bufalin-treated than control rats at equivalent renal perfusion pressures. The slope of the line describing the relation between urine flow and renal perfusion pressure was greater (P < .05) in control than bufalin-treated rats. Similarly, the slope of the line relating sodium excretion to renal perfusion pressure was greater (P < .05) in control than bufalin-treated rats. Thus, acute increases in blood pressure during Na+, K+-ATPase inhibition are associated with impaired renal autoregulation and pressure natriuresis. This effect may be important in chronic hypertension associated with Na+,K+-ATPase inhibition in the rat.