THE ROLE OF ADIPONECTIN AND TOLL-LIKE RECEPTOR 4 GENE POLYMORPHISMS ON NON-PROLIFERATIVE RETINOPATHY IN TYPE 2 DIABETES MELLITUS PATIENTS. A CASE-CONTROL STUDY IN ROMANIAN CAUCASIANS PATIENTS.

CONTEXT: Persistent inflammation and impaired neovascularization are important contributors to the development of diabetic retinopathy (DR). Gene polymorphisms of adiponectin (APN) were demonstrated to have an important role on the plasma level and activity of adiponectin. APN has anti-inflammatory, anti-diabetic and anti-atherogenic properties. Toll-Like Receptor 4 (TLR4) is a critical mediator of innate immunity. Polymorphisms in TLR-4 gene were shown to be associated with impaired inflammatory response in diabetes. OBJECTIVE: The aim of the study was to analyze the association of +276G>T variant of APN gene and Asp299Gly and Thr399Ile of TLR-4 gene variants in relationship with T2DM and DR in an Eastern European population group. DESIGN: The distribution of the mutant alleles in 198 T2DM patients with DR and 200 non-T2DM controls was examined. Genomic DNA from T2DM patients and healthy controls genotyped through the use of PCR-RFPL assay. RESULTS: Genotype and allele frequencies of the Asp299Gly and Thr399Ile polymorphisms differed between T2DM patients and non diabetic subjects (P<0.001). Moreover, the presence of the minor alleles of these polymorphisms were significantly identified as protective factors against T2DM, under a dominant model of Fisher's exact test (χ2=4.988, phi=0.745, OR=0.767, 95% CI=0.602-0.867, P<0.001; respectively χ2=5.254, phi=0.820, OR=0.487, 95% CI=0.211-0.648, P<0.001). Genotype analysis for the adiponectin 276G>T gene polymorphism yielded no significant association with T2DM, but revealed a borderline significance for the association with DR (χ2=5.632, phi=0.423, OR =1.101, 95% CI=0.887-1.203, P=0.009). CONCLUSIONS: We found an association between the TLR4 Asp299Gly and Thr399Ile polymorphisms and protection for DR. The APN genetic polymorphism is not associated with T2DM.

How iMALDI can improve clinical diagnostics.

Protein mass spectrometry (MS) is an indispensable tool to detect molecular signatures that can be associated with cellular dysregulation and disease. Despite its huge success in the life sciences, where it has led to novel insights into disease mechanisms and the identification of potential protein biomarkers, protein MS is rarely used for clinical protein assays. While conventional matrix-assisted laser desorption/ionization (MALDI) MS is not compatible with complex samples, liquid chromatography-MS (LC-MS)-based assays may be too complex and may lack the robustness and ease of automation required for routine use in the clinic. Therefore, clinical protein assays are dominated by immunohistochemistry and immunoassays which, however, often lack standardization and fully depend on antibody specificity. Immuno-MALDI (iMALDI) MS may overcome these hurdles by utilizing anti-peptide antibodies for the specific enrichment of targeted analytes and on-target detection of the captured analytes, thus combining the unique properties of MS for the unambiguous detection and quantitation of analytes with a workflow that can be fully automated. Here we discuss the requirements for clinical protein assays, the pitfalls of existing methods, how iMALDI has been successfully used to quantify endogenous peptides and proteins from clinical samples, as well as its potential as a powerful tool for companion diagnostics in the light of precision medicine.

THE RESTLESS LEGS SYNDROME (REVIEW).

The restless legs syndrome (RLS), also known as Willis-Ekbom disease, is a common sleep related neurological disorder with prevalence between 1 and 10%, increasing with age. Women are more frequently affected than men. RLS is characterized by an urge to move the legs accompanied by uncomfortable and unpleasant sensations in the legs, worsening of complaints during periods of rest, improvement by movement and an increase of symptoms in the evening or at night. In addition, affected patients may also suffer from severe sleep disorders and negative effects on daily activities. There is often a history of RLS among first-degree relatives, especially with the primary form. Among other, comorbidities or causal factors are iron deficiency, terminal renal insufficiency, pregnancy, polyneuropathy, or psychotropic drugs. The etiology of primary (idiopathic) RLS has not been clarified yet; however, genetic factors and dysfunctional dopaminergic neurotransmission as well as alterations of central iron metabolism play an important role. In addition to non-pharmacological treatment such as lifestyle modifications or behavioral strategies, levodopa, dopamine agonists, or anticonvulsants are effective. Opioids may be used in otherwise refractory forms. In the case of secondary or comorbid RLS, treatment of the underlying disease is necessary.

GSTM1, GSTT1 and GSTP1 Genetic Variants in Multiple Urologic Cancers.

INTRODUCTION: Glutathione S-transferases (GSTs) are phase 2 enzymes responsible for catalyzing the biotransformation of a wide variety of electrophilic compounds, having a crucial role in the detoxification of active metabolites of procarcinogens produced by phase 1 reactions, tying them to glutathione and promoting their excretion in the urine. OBJECTIVES: we evaluated GSTM1, GSTT1 and GSTP1 genotypes in patients diagnosed with multiple malignancies, of which at least one was found in the prostate, bladder or kidney. MATERIALS AND METHODS: GSTM1, GSTT1 and GSTP1 genotypes were genetically assessed in 34 patients with multiple urologic cancers and 23 patients with urologic cancer associated with another type of cancer. RESULTS: in the group of patients with multiple urologic cancers, GSTT1 null genotype was found in 26.4% of patients compared to 0% in controls, 82.35 % of patients and 47% of witnesses carried at least one GSTM1 or GSTT1 null genotype, and in the group with different cancers, GSTM1 null genotype was found in 52.1% of patients compared to 4.3% witnesses in the control group; GSTT1 null genotype was found in 34.7% of patients compared to 4.3% of witnesses, atleast one GSTM1 or GSTT1 null genotype was found in 73.9% of patients compared to 8.6% of controls. CONCLUSIONS: GSTT1 null genotype is a risk factor for patients with more primitive urologic malignancies (bladder, prostate and kidney); GSTM1 or GSTT1 null genotype is more frequent in patients with multiple urologic tumors; GSTM1 and GSTT1 null genotypes are risk factors in patients with different types of cancer, with at least one affecting the urinary system.

GSTM1, GSTT1 and GSTP1 in patients with multiple breast cancers and breast cancer in association with another type of cancer.

INTRODUCTION: breast cancer has the highest incidence in women.Glutathione S-transferases (GSTs) are a large group of enzymes involved in the metabolism of xenobiotics. The members of this gene superfamily are involved in the development of multiple cancers. OBJECTIVES: the aim of the study was to see whether the GSTM1, GSTT1 and GSTP1 genetic polymorphisms are risk factors for patients diagnosed with multiple malignancies, of which at least one is located in the breast. MATERIALS AND METHODS: in the period between 2005 and 2012,of the 520 patients diagnosed with breast cancer, 69 had multiple primitive malignant tumors, of which at least one was localized in the breast. The research on GSTM1, GSTT1 and GSTP1 genotypes consisted of 59 patients diagnosed with multiple breast cancers or with breast cancer in association with another type of cancer, compared with a group of healthy controls. RESULTS: in the subgroup of patients with breast cancer in association with another type of cancer, the GSTM1 null genotype was present in 61.2% of patients, compared to 29% of controls; the subgroup of metachronous breast cancers, the presence of any of the GSTT1 or GSTM1 null genotypes was statistically significantly different from that of controls (65.2%vs. 28.5%); in the subgroup with synchronous cancers, the GSTM1 null genotype was found in 66.6% of patients compared to 9% for the controls, and the presence of any null genotype (GSTM1 and GSTT1) was also statistically significant in the case group. CONCLUSIONS: the GSTM1 null genotype is a risk factor for synchronous breast cancers and for breast cancer associated with extramammary cancer; the presence of null genotypes(GSTM1 or GSTT1) is a risk factor for multiple breast cancer(bilateral or synchronous); the GSTT1 null genotype and the heterozygous variant allele (Ile105Val) and homozygous variant allele (Val105Val) of GSTP1 are not risk factors for the cases studied.

Impact of daytime sleepiness on rehabilitation outcome in the elderly.

Daytime sleepiness (DS) is associated with poor health, impaired physical functioning, as well as somatic and psychiatric morbidity. The impact of DS on functional outcome in the elderly is unknown. We investigated whether observed daytime sleepiness in geriatric patients with moderate to severe functional impairment was associated with functional clinical outcomes. We addressed the issue by determining the impact of observed daytime sleepiness, by means of the Essener Questionnaire of Age and Sleepiness (EQAS), on improvement in functional status - measured by the Barthel ADL Index - among disabled geriatric in-patients. We included 129 patients, 28 (22%) were male and 101 (78%) were female. Sleepiness according to EQAS scale was absent in 27 (21%) patients, mild in 71 (55%) patients and moderate to severe in 31 (24%) patients. The three patient groups did not differ in the Barthel ADL Index (BI) on admission or co-morbid conditions. Geriatric treatment was comparable across groups. Improvement in the BI of at least 1 standard deviation (SD) occurred in 23/27 (85%) of subjects without sleepiness, in 53/71 (75%) of subjects with mild to moderate sleepiness and in 15/31 (44%) of subject with severe sleepiness (p < 0.01). BI increased at least 2 SD in 20/27 (74%), 38/71 (54%) and 11/31 (35%) individuals, respectively (p < 0.02). We conclude that the daytime sleepiness predicts a poorer functional recovery rate in older patients during geriatric in-hospital rehabilitation. Furthermore, we found a significant association and a dose response relationship between severity of daytime sleepiness and improvement in Barthel ADL Index.

Validation of the Essener Questionnaire of Age and Sleepiness in the elderly using pupillometry.

In the elderly population, daytime sleepiness (DS) is a burden that affects quality of life, cognitive and physical functioning as well as health status and morbidity. The measurement of DS in older subjects continues to be a challenge, as there are only few elderly-specific assessment tools available. Therefore, we compared the newly developed Essener Questionnaire of Age and Sleepiness (EQAS) with pupillography, a physiological measure of sleepiness. The aim was to identify EQAS cut-off values for increased daytime sleepiness. For the validation study, we determined EQAS scores and the pupillary unrest index (PUI) of the pupillographic sleepiness test (PST) in 88 geriatric in-patients. We also collected data on age, gender, co-morbidities, and geriatric assessment in these subjects. Of all included patients 37 (42%) completed the PST. Fourteen (16%) subjects refused to participate and 37 (42%) subjects could not complete 11 min required for a valid PUI. Subjects with complete and incomplete pupillometry did not differ in basic assessment parameters of health status or cognitive functioning. EQAS scores correlated significantly with PUI values (r = 0.70; p < 0.001) demonstrating a dose-response relationship. Based on ROC analysis, an EQAS score above 3 was optimal to distinguished sleepy from non-sleepy participants with sensitivity of 67%, specificity of 93% and positive and negative predictive values of 75% and 90%, respectively. In conclusion, the high negative and positive predictive values of the EQAS indicate that this instrument is a useful and valid assessment tool for daytime sleepiness in the elderly. The easy administration of this observational instrument favors its adoption in geriatric medicine.

GST gene variants in synchronous colorectal cancers and synchronous association of colorectal cancers with other cancers.

BACKGROUND: the present study evaluates genetic polymorphisms of three glutathione S-transferases (GSTM1, GSTT1and GSTP1) in patients with synchronous malignant colorectal tumors and the association of synchronous colorectal cancers with other cancers. MATERIAL AND METHODS: from 420 patients with a colorectal cancer admitted to our hospital between 2005-2012, we selected for genetic analysis 20 patients with multiple synchronous malignant colorectal tumors and 9 patients with asynchronous association of colorectal cancer with another cancer. We searched for GST genotypes, comparing the results with controls. RESULTS: the genetic analysis was possible only in 19 patients with colorectal synchronous cancers and 9 patients with asynchronous association of colorectal cancer with another cancer; we found a statistically significant difference for null GSTM1 genotype frequency between these patients and the control group; we found no differences regarding the frequency of null GSTT1 genotype and Ile105Val polymorphism of GSTP1 in patients with synchronous cancers compared with the control group. CONCLUSION: in our study we found the null GSTM1 genotype as a risk factor for multiple colorectal synchronous cancers and for an association of synchronous colorectal with other cancers

Multiple malignant tumors.

BACKGROUND: Due to the improvement in diagnosis and therapy for certain malignant tumors, we are now faced with patients who develop in time multiple malignancies. METHODS: We conducted a retrospective analysis of the patients diagnosed with at least two primary cancers that were admitted and treated in Cluj-Napoca Municipal Hospital. The study followed patients for a period of 7.5 years. RESULTS: We included in the present study 217 patients (4.33%) with two or more malignant primary tumors from 5003 cases diagnosed with a primary cancer. The most common sites for multiple malignant tumors were related to the breast, colorectum, urinary bladder, prostate and kidneys. CONCLUSIONS: We should always take into consideration the possibility of synchronous tumors and we have to keep in mind that a successful treatment of cancer might not prevent the onset of another primary mass.

Phorbol 12-myristate 13-acetate potentiation of N-methyl-D-aspartate-induced currents in primary cultured cerebellar granule cells is mediated by protein kinase C alpha.

We have previously reported that activation of protein kinase C (PKC) by phorbol 12-myristate 13-acetate (PMA) results in potentiation of N-methyl-D-aspartate-induced currents (I(NMDA))of receptors contained in primary cultured cerebellar granule cells (CGCs). The purpose of this study was to identify which PKC isoform(s) was responsible for this effect by using the whole-cell patch-clamp technique. Experiments were conducted on CGCs that expressed both the NR2A and NR2B NMDA receptor subunits as well as the PMA-sensitive PKC isoforms alpha, betaI, betaII, delta, epsilon, gamma, and . As observed previously, N-methyl-D-aspartate-induced peak currents (I(Pk)) were enhanced by a 12.5-min, 100 nM PMA exposure at 37 degrees C under normal recording conditions. Potentiation of receptor function was not observed when extracellular Ca(2+) was removed and 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid was present inside the cell. PMA-induced potentiation of I(Pk) did not occur when PKCalpha-specific antibody was introduced into the cell via the recording electrode. However, in similar experiments with antibodies specific for PKCbetaII, delta, epsilon, gamma, and , PMA potentiation of I(Pk) was observed. Down-regulation of PMA-sensitive PKC isoforms by an overnight exposure of 100 nM PMA resulted in lack of potentiation by PMA that was rescued when catalytically active PKCalpha was introduced into the cell via the patch electrode. PMA potentiation of I(Pk) was not recovered when catalytically active PKCbetaI, PKCbetaII, or PKCgamma was introduced into the cell via the patch electrode. Collectively, our data provide strong evidence that PMA-enhanced function of native NMDA receptors expressed in primary cultured CGCs is mediated by activation of PKCalpha.

Ultrasonic diagnostic instruments.

The underlying physical principles and current limitations of diagnostic ultrasonic instruments are reviewed. Recently developed ultrasonic imaging devices using pulsed-reflected ultrasound are discussed in detail. These instruments transmit short trains of 1.5- to 10-megahertz sound. Echoes reflected from tissue are converted to electrical signals, which are presented on a display device to outline the contour of tissues and organs within the body. The physical resolution of the system is dependent on several design factors in addition to the transmitted sound frequencies. A resolution volume of approximately 1.5 by 3 by 4 millimeters is achieved optimally with commercially available systems operating at 2.25 megahertz. The various instrument designs are described in the context of clinical usage. Because the sound is diffracted, refracted, and reflected, tghe imaging considerations are different from those of x-ray imaging. Diagnostic devices based on the Doppler principle are distinguished from pulsed-reflected ultrasonic instruments.

Cerebellar granule cells cultured from adolescent rats express functional NMDA receptors: an in vitro model for studying the developing cerebellum.

In the developing rat cerebellum functional NMDA receptors (NMDARs) expressing the NR2C subunit have been identified on or after postnatal day 19. We obtained primary cultured cells from 19- to 35-day-old rat cerebellum that expressed few oligodendrocytes or astrocytes. Cultured cells were immunoreactive for neuron-specific proteins thus indicating a neuronal population. The primary neuron present was the granule cell as indicated by immunofluorescence for the GABA(A) alpha 6 subunit. Whole-cell patch-clamp experiments indicated that functional NMDARs were present. Functional characteristics of NMDARs expressed in cerebellar granule cells (CGCs) obtained from adolescent animals were similar to those previously reported for NMDARs expressed in CGCs obtained from neonatal rats. Cultured CGCs obtained from older animals contained NMDARs that were inhibited by EtOH and were less sensitive to the NR2B subunit-specific antagonist Ro 25-6981. Furthermore, NMDA-induced currents were smaller than those observed in CGCs. Western blot analysis indicated the presence of the NMDA NR2A and NR2C subunits, but not the NR2B in cultures obtained from the adolescent rats. CGCs obtained from adolescent rats express functional NMDARs consistent with a developmental profile observed in vivo.

Activation of protein kinase C enhances NMDA-induced currents in primary cultured cerebellar granule cells: Effect of temperature and NMDA NR2 subunit composition.

The purpose of this study was to determine the effect of protein kinase C (PKC) activation by 100 nM phorbol 12-myristate 13-acetate (PMA) on N-methyl-d-aspartate (NMDA) receptor function with the whole-cell patch-clamp technique. Receptors expressed in primary cultured cerebellar granule cells at days in vitro that result in different NMDA NR2A and NR2B subunit composition were assessed. The effect of temperature during PMA exposure on NMDA-induced current amplitudes as well as PMA-induced translocation of PKC isoform-specific immunoreactivity was also assessed. We observed that PMA augmented NMDA-induced peak current amplitude regardless of NR2 subunit composition and augmentation of NMDA-induced steady-state current amplitudes was only observed in 13 and older days in vitro cerebellar granule cells. PMA treatment did not affect the desensitized state (steady-state to peak current ratios) of the receptor. Augmentation of NMDA-induced current amplitude was seen by 12.5 min PMA exposure, a time that corresponded with translocation of all PMA-sensitive PKC isoform immunoreactivity. PMA exposure at 37 degrees C resulted in a significant enhancement of NMDA-induced current amplitude compared to augmentation of receptor function following a PMA exposure at 23 degrees C. Translocation of PKC immunoreactivity was also greatly attenuated at 23 degrees C compared to treatment at 37 degrees C. While our data support previous observations that activation of PKC by PMA enhances NMDA receptor function, this augmentation does not appear to be dependent upon NR2 subunit composition. Furthermore our data emphasize the importance of conducting experiments at physiological temperatures when assessing PKC effects on native NMDA receptors.

Positron emission tomography findings in obstructive sleep apnea patients with residual sleepiness treated with continuous positive airway pressure.

Despite sufficient continuous positive airway pressure (CPAP) therapy, some patients with the obstructive sleep apnea syndrome (OSAS) still suffer from excessive daytime sleepiness (EDS). In some of them, no cause of the persistence of EDS can be found. Brain damage due to nocturnal hypoxemia is a potential cause for this unclear persistent sleepiness (UPS). This study was done to evaluate this hypothesis. Patients with UPS were identified among the OSAS patients, who came for a CPAP therapy checkup to our sleep laboratory. UPS was recognized when no explanation for persistent EDS could be yielded by standard diagnostic procedures. Out of 167 patients under CPAP therapy 13 had UPS. To investigate the brain morphology, positron emission tomography (PET) scanning with the tracer fluorine-18 fluorodeoxyglucose (FDG), called FDG-PET, were performed in 7 of the UPS patients. Abnormal PET findings were concentrated in frontal area (found in 4 patients). The frontal abnormality seems to distinguish the OSAS patients with UPS from the whole OSAS population, examined in previous studies.

Characterization of protein kinase C isoforms in primary cultured cerebellar granule cells.

Protein kinase C (PKC) is a family of serine/threonine kinases comprised of 10 isoforms. Although commercial antibodies are available for all 10 isoforms, the specificity of these antibodies has been questioned. We have identified immunoblot conditions in which commercially purchased PKC antibodies are specific for their respective isoform. We then used these conditions to determine that PKC isoforms alpha, betaI, betaII, delta, epsilon, gamma, lambda, theta, and zeta are present in rat primary cultured cerebellar granule cells (CGCs) 6-14 days in vitro (DIV). This PKC profile is identical to that observed in cerebellar homogenates taken from 6-, 14- and 21-day-old rats. Western blot analysis indicated that the classical and the atypical PKC isoforms were more prevalent in the cytosolic subcellular fraction compared to the particulate fraction under basal conditions. Immunoreactivity for the novel isoforms tended to be higher in the particulate fraction under basal conditions. Phorbol 12-myristate 13-acetate (PMA) treatment resulted in translocated immunoreactivity from the cytosolic to the particulate fraction for all of the classical and novel PKC isoforms, but not for the atypical isoforms. However, the degree of translocation as well as the speed of translocation varied among the isoforms. The stability of the individual isoforms after PMA-induced activation also varied among the isoforms. Differences in these parameters were dependent upon culture batches and PKC isoform groups. We have identified experimental conditions in which reproducible results can be obtained with primary cultured CGCs in the study of PKC. We discuss possible solutions for problems encountered when utilizing primary cultured neurons to study PKC-mediated signal transduction.

A calcium and ATP sensitive nonselective cation channel in the antiluminal membrane of rat cerebral capillary endothelial cells.

The patch-clamp technique was applied to the antiluminal membrane of freshly isolated capillaries of rat brain (blood-brain barrier). With 1.3 mM Ca2+ in the bath, excision of membrane patches evoked ion channels, which could not be observed in cell-attached mode. The channel was about equally permeable to Na+ and K+ ions, but not measurable permeable to Cl- and the divalent ions Ca2+ and Ba2+. The current-voltage curve was linear in the investigated voltage range (-80 mV to +80 mV), and the single-channel conductance was 31 +/- 2 pS (n = 22). The channel open probability was not dependent on the applied potential. Lowering of Ca2+ to 1 microM or below on the cytosolic side inactivated the channels, whereas addition of cytosolic ATP (1 mM) inhibited channel activity completely and reversibly. The channel was blocked by the inhibitor of nonselective cation channels in rat exocrine pancreas 3',5-dichlorodiphenylamine-2-carboxylic acid (DCDPC, 10 microM) and by the antiinflammatory drugs flufenamic acid (greater than 10 microM) and tenidap (100 microM), as well as by gadolinium (10 microM). Thus, these nonselective cation channels have many properties in common with similar channels observed in fluid secreting epithelia. The channel could be involved in the transport of K+ ions from brain to blood side.

Differential association of transfer RNAs with the genomes of murine, feline and primate retroviruses.

The tRNAs that are bound to the genomic RNAs of several murine, feline, and primate retroviruses have been identified. Transfer RNAs were divided into those loosely bound and those tightly bound by stepwise thermal dissociation of the 70 S RNA. They were then identified and semiquantitated by aminoacylation. Proline tRNA is the most tenaciously bound tRNA in several strains of murine leukemia virus, two strains of feline leukemia virus, and the primate viruses simian sarcoma, baboon endogenous, and gibbon ape lymphoma. In the feline xenotropic virus, RD-114, tRNAGly is enriched in the most tightly bound fraction. In Mason-Pfizer monkey virus, as in the murine mammary tumor virus, tRNALys is the tRNA most tenaciously bound to its genomic RNA. Besides the most tightly associated tRNA, one or more different tRNAs are found in relatively large amounts in association with the 70 S RNA. (For convenience, we refer to the largest RNA ccomplex (50-70 S) isolated from any of the retroviruses studies as '70 S' RNA.) These tRNAs can be distinguished from the most tightly bound tRNA by the fact that they can be dissociated at lower temperatures. However, they occur in the same relative abundance as the tightly bound tRNA.

Proinflammatory mediators chronically downregulate the formation of the endothelium-derived hyperpolarizing factor in arteries via a nitric oxide/cyclic GMP-dependent mechanism.

BACKGROUND: Endothelium-dependent dilator responses mediated by NO and endothelium-derived hyperpolarizing factor (EDHF) are altered in arteriosclerosis and sepsis. The possibility that proinflammatory mediators that stimulate the expression of inducible NO synthase (NOS II) affect the generation of EDHF was examined in isolated arteries. METHODS AND RESULTS: Under combined blockade of NOS and cyclooxygenase, EDHF-mediated relaxation elicited by several agonists was significantly attenuated in rabbit carotid and porcine coronary arteries exposed to cytokines and lipopolysaccharide. The blunted relaxation was coincident with NOS II expression and was prevented by inhibition of NOS II as well as of global protein synthesis. The NO donor CAS 1609 and 8-bromo-cGMP mimicked the proinflammatory mediator effect. In contrast, long-term blockade of endothelial NO generation increased the relaxation in carotid but not in coronary arteries. Proinflammatory mediators reduced the synthesis of EDHF assessed as hyperpolarization of vascular smooth muscle cells elicited by the effluent from bradykinin-stimulated coronary arteries. Proinflammatory mediators induced NOS II expression in cultured endothelial cells and decreased the expression of cytochrome P450 enzymes, which are the most probable candidates for the synthesis of EDHF. CONCLUSIONS: Proinflammatory mediators inhibit the formation of EDHF in isolated arteries. This impairment is coincident with NOS II expression in the arterial wall and seems to be mediated through the induced generation of NO, which downregulates the putative EDHF-forming enzyme. Thus, a decreased formation of EDHF may contribute to the endothelial dysfunction in arteriosclerosis and sepsis.

Lessons from in vitro models of small, irregular, multiple and tunnel-like stenoses relevant to clinical stenoses of valves and small vessels.

This review examines data on the accuracy of the simplified Bernoulli equation for quantitation of pressure drops across small, irregular, multiple and tunnel-like stenoses. This information is drawn from in vitro models of such cardiovascular stenoses and explores the limits of this simplification as they affect accuracy in special situations. Within the physiologic range, discrete small and irregular stenoses present no problems for the measurement of pressure drops using the simplified Bernoulli equation. Multiple side by side orifices of different dimension also give reasonable data using this approach. Tunnel-like stenoses of very small diameter and finite length produce underestimation of the true pressure drop through the stenosis when the simplified Bernouli equation is used. This underestimation is primarily due to neglect of the energy consumed by viscous friction in this situation. These considerations are especially pertinent to the problem of measuring pressure gradients across coronary vessels to assess their clinical significance as well as the adequacy of angioplasty and other intravascular interventional techniques. Because this area needs further exploration, some discussion of in vitro models as such as included.

Two-dimensional echocardiographic assessment of bioprosthetic valve dysfunction and infective endocarditis.

Two-dimensional echocardiography of Hancock porcine heterograft valves was evaluated by correlation with clinical, hemodynamic, angiographic and pathologic findings in 80 patients. Ninety-five aortic and mitral bioprostheses were categorized by the type of valvular abnormality: group I, dysfunction due to primary tissue failure (41 valves); group II, dysfunction due to paravalvular leakage without infection (5 valves); group III, infective endocarditis with or without hemodynamic dysfunction (28 valves); and group IV, control cases without dysfunction or infection (21 valves). Increased size of a bioprosthetic leaflet image (minimal dimensions 3 x 5 mm) was observed in 46% (19 of 41) of cases with primary tissue failure and in 62% (10 of 16) of cases with leaflet vegetations due to endocarditis. Prolapse of leaflet echoes to below the level of the bioprosthetic sewing ring occurred in 76% (28 of 37) of cases with torn leaflets and also in 46% (6 of 13) of valves with vegetations on intact leaflets. Antegrade extension of leaflet echoes to beyond the level of the stents, observed in 4 of 16 cases with leaflet vegetations, was the only echocardiographic sign distinguishing leaflet infection from leaflet degeneration. Aortic bioprostheses with ring dehiscence affecting 40 to 90% of the anular circumference showed motion discordant with the motion of the adjacent aortic root and native anulus. Although echocardiographic abnormalities are frequently observed with bioprosthetic leaflet degeneration or infection, the echocardiographic appearance often does not distinguish between these two major complications and is best interpreted concurrently with other clinical and laboratory assessment.