Stimulation of angiotensin AT2 receptors by the non-peptide agonist, Compound 21, evokes vasodepressor effects in conscious spontaneously hypertensive rats

BACKGROUND AND PURPOSE

Angiotensin type 2 receptor (AT(2) receptor) stimulation evokes vasodilator effects in vitro and in vivo that oppose the vasoconstrictor effects of angiotensin type 1 receptors (AT(1) receptors). Recently, a novel non-peptide AT(2) receptor agonist, Compound 21, was described, which exhibited high AT(2) receptor selectivity.

EXPERIMENTAL APPROACH

Functional cardiovascular effects of the drug candidate Compound 21 were assessed, using mouse isolated aorta and rat mesenteric arteries in vitro and in conscious spontaneously hypertensive rats (SHR).

KEY RESULTS

Compound 21 evoked dose-dependent vasorelaxations in aortic and mesenteric vessels, abolished by the AT(2) receptor antagonist, PD123319. In vivo, Compound 21 administered alone, at doses ranging from 50 to 1000 ng.kg(-1).min(-1) over 4 h did not decrease blood pressure in conscious normotensive Wistar-Kyoto rats or SHR. However, when given in combination with the AT(1) receptor antagonist, candesartan, Compound 21 (300 ng.kg(-1).min(-1)) lowered blood pressure in SHR only. Further analysis in separate groups of conscious SHR revealed that, at a sixfold lower dose, Compound 21 (50 ng.kg(-1).min(-1)) still evoked a significant depressor response in adult SHR ( approximately 30 mmHg) when combined with different doses of candesartan (0.01 or 0.1 mg.kg(-1)). Moreover, the Compound 21-evoked depressor effect was abolished when co-infused (50 microg.kg(-1).min(-1) for 2 h) with the AT(2) receptor antagonist PD123319.

CONCLUSION AND IMPLICATIONS

Collectively, our results indicate that acute administration of Compound 21 evoked blood pressure reductions via AT(2) receptor stimulation. Thus Compound 21 can be considered an excellent drug candidate for further study of AT(2) receptor function in cardiovascular disease.

Radial peripapillary capillaries of the retina. II. Possible role in Bjerrum scotoma

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Design and fast synthesis of C-terminal duplicated potent C(2)-symmetric P1/P1'-modified HIV-1 protease inhibitors

An analysis of the X-ray structure of a complex of HIV-1 protease with a linear C(2)-symmetric C-terminal duplicated inhibitor guided the selection of a series of diverse target compounds. These were synthesized with the objective to identify suitable P1/P1' substituents to provide inhibitors with improved antiviral activity. Groups with various physical properties were attached to the para-positions of the P1/P1' benzyloxy groups in the parent inhibitor. A p-bromobenzyloxy compound, prepared in only three steps from commercially available starting materials, was utilized as a common precursor in all reactions. The subsequent coupling reactions were completed within a few minutes and relied on palladium catalysis and flash heating with microwave irradiation. All of the compounds synthesized exhibited good inhibitory potency in the protease assay, with K(i) values ranging from 0.09 to 3.8 nM. A 30-fold improvement of the antiviral effect in cell culture, compared to the parent compound, was achieved with four of the inhibitors. The differences in K(i) values were not correlated to the differences in antiviral effect, efficiency against mutant virus, or reduced potency in the presence of human serum. The poorest enzyme inhibitors in fact belong to the group with the best antiviral effect. The binding features of two structurally related inhibitors, cocrystallized with HIV-1 protease, are discussed with special emphasis on the interaction at the enzyme/water phase.

Design and synthesis of new potent C2-symmetric HIV-1 protease inhibitors. Use of L-mannaric acid as a peptidomimetic scaffold

A study on the use of derivatized carbohydrates as C2-symmetric HIV-1 protease inhibitors has been undertaken. L-Mannaric acid (6) was bis-O-benzylated at C-2 and C-5 and subsequently coupled with amino acids and amines to give C2-symmetric products based on C-terminal duplication. Potent HIV protease inhibitors, 28 Ki = 0.4 nM and 43 Ki = 0.2 nM, have been discovered, and two synthetic methodologies have been developed, one whereby these inhibitors can be prepared in just three chemical steps from commercially available materials. A remarkable increase in potency going from IC50 = 5000 nM (23) to IC50 = 15 nM (28) was observed upon exchanging -COOMe for -CONHMe in the inhibitor, resulting in the net addition of one hydrogen bond interaction between each of the two -NH- groups and the HIV protease backbone (Gly 48/148). The X-ray crystal structures of 43 and of 48 have been determined (Figures 5 and 6), revealing the binding mode of these inhibitors which will aid further design.

A Drosophila kinesin-like protein, Klp38B, functions during meiosis, mitosis, and segmentation

We show that klp38B, isolated as a mutation that dominantly prolongs blastoderm mitotic cycles in Drosophila, encodes a Drosophila kinesin-like protein. Further genetic analyses show that Klp38B not only functions during mitosis, but is also required for meiosis and abdominal segmentation. Sequence comparisons suggest that Klp38B encodes an amino-terminal microtubule motor domain, a central alpha-helical coiled-coil domain, and a C-terminal globular domain. Evidence that Klp38B is required during meiosis is that flies transheterozygous for mutations in both klp38B and nod have a high frequency of 4th chromosome meiotic nondisjunction. Nod is a chromokinesin, a chromosome binding kinesin, that is believed to provide astral-exclusion forces during the metaphase stage of meiosis. Evidence that Klp38B is required during mitosis is that embryos from female germline clones of klp38B mutations have holes in the cuticle similar to a zygotic string (dCDC25) phenotype. Also, anti-Klp38B antibody injection into precellularization blastoderm embryos causes developmental arrest and the formation of circular mitotic figures. We speculate, based on these phenotypes, that Klp38B is a chromokinesin that provides astral-exclusion forces on the chromosomes during meiosis and mitosis. Consistent with this hypothesis, we have identified an HMG-1 homologous region on Klp38B that could potentially bind AT-rich DNA sequences. Finally, we show that klp38B mutations have defects in abdominal segmentation, suggesting that Klp38B, like Xenopus chromokinesin Xklp1, might be involved in polar granule formation.

Membrane fusion proteins are required for oskar mRNA localization in the Drosophila egg chamber

We used a genetic screen in Drosophila to identify mutations which disrupt the localization of oskar mRNA during oogenesis. Based on the hypothesis that some cytoskeletal components which are required during the mitotic divisions will also be required for oskar mRNA localization during oogenesis, we designed the following genetic screen. We screened for P-element insertions in genes which slow down the blastoderm mitotic divisions. A secondary genetic screen was to generate female germ-line clones of these potential cell division cycle genes and to identify those which cause the mislocalization of oskar mRNA. We identified mutations in ter94 which disrupt the localization of oskar mRNA to the posterior pole of the oocyte. Ter94 is a member of the CDC48p/VCP subfamily of AAA proteins which are involved in homotypic fusion of the endoplasmic reticulum during mitosis. Consistent with the function of the yeast ortholog, ter94-mutant egg chambers are defective in the assembly of the endoplasmic reticulum. We tested whether other membrane biosynthesis genes are required for localizing oskar mRNA during oogenesis. We found that ovaries that are mutant for syntaxin-1a, rop, and synaptotagmin are also defective in oskar mRNA localization during oogenesis. We suggest a pathway for the role of membrane assembly proteins on oskar mRNA localization.

The clinical, histologic, and treatment spectrum in necrotizing sialometaplasia

OBJECTIVES

The aim of this report was the clinical and histologic characterization of necrotizing sialometaplasia.

STUDY DESIGN

We performed a retrospective case series analysis.

RESULTS

The study included 4 women 29-71 years old. Possible contributing factors (drugs, alcohol abuse, bulimia, smoking, and pancreatic cancer) were identified. Patients presented with unilateral or bilateral rapidly progressing painful palatal ulcers. Necrotic salivary glands and inflammation were universal microscopic features; ductal metaplasia was present in only 1 case. Thrombosis and heavy fungal and bacterial overgrowth were observed in 1 case. In 3 of the cases the lesions healed within 4-6 weeks under conservative supportive care, whereas in 1 case persistent enlargement up to 25 mm diameter was observed. Surgical debridement combined with a palatal guard resulted in complete healing within 12 weeks.

CONCLUSIONS

Significant variations may be observed in both clinical and microscopic manifestations of necrotizing sialometaplasia. Although this disease is considered to be self-limiting in the majority of cases, surgical intervention can be considered in unusually large cases.

P1/P1' modified HIV protease inhibitors as tools in two new sensitive surface plasmon resonance biosensor screening assays

The commonly used HIV-1 protease assays rely on measurements of the effect of inhibitions on the hydrolysis rate of synthetic peptides. Recently an assay based on surface plasmon resonance (SPR) was introduced. We have taken advantage of the fact that the SPR signal is proportional to the mass of the analyte interacting with the immobilised molecule and developed two new improved efficient competition assay methods. Thus, high molecular weight binders were used as amplifiers of the surface plasmon resonance signal. Linkers were attached by a Heck reaction to the para-positions of the P1/P1' benzyloxy groups of a linear C2-symmetric C-terminal duplicated inhibitor to enable (a) biotin labelling or (b) direct immobilisation of the inhibitor to the biosensor surface matrix. The interaction properties of a series of 17 structurally diverse inhibitors was assessed and compared to previously reported data. The most sensitive assay was obtained by immobilising the enzyme and amplifying the signal with an antibody, giving a detection range between 0.1 nM and 10 microM. Immobilisation of the inhibitor resulted in a stable and durable surface but a narrower detection range (1-100 nM). The two competition assays are anticipated to be very suitable for fast screening of potential HIV inhibitors.

V-stand--a versatile surgical platform for oromandibular reconstruction using a 3-dimensional virtual modeling system

PURPOSE

The challenge of oromandibular reconstruction (OMR) after oncologic resections has been repeatedly addressed in the literature. Although final oncologic margins can be decided only during surgery, various attempts have been made to create an ideal and accurate platform for OMR. The purpose of this article is to present the V-stand, a versatile surgical platform for OMR using a 3-dimensional (3D) virtual modeling system.

MATERIALS AND METHODS

Seventeen patients requiring an OMR were included in the study. A presurgical computed tomogram was obtained and virtual resection and reconstruction with a free fibular flap were planned using 3D virtual surgery software. The mandible was reconstructed intraoperatively using the V-stand, which served as a template for the lower border of the mandible and the lateral aspects of the stand were fixed to the proximal mandibular segments using 2-mm titanium screws.

RESULTS

Patients' average age was 53 years (5 to 72 yr). Median follow-up was 19 months (2 to 35 months). All reconstructed mandibles resulted in good function and esthetics.

CONCLUSIONS

The V-stand offers a safe and time-efficient method for OMR. It provides an excellent means for accurate spatial positioning of a fibular free flap. The V-stand preserves the original dimensions of the reconstructed mandible and can overcome surgical ablation modifications because it is not dependent on the precision of the resection, but rather provides a mold for the entire mandible.

Oral intravascular fasciitis: a rare maxillofacial lesion

Nodular fasciitis is a benign non-neoplastic myofibroblastic proliferation, involving the head in 7% to 20% of cases. Intravascular fasciitis (IVF) is a rare variant, with a unique intravascular growth pattern. Only 4 maxillofacial cases have been previously reported. We describe a 58-year-old woman with a rapidly growing, hard, mobile buccal submucosal swelling. CT scans identified a well-defined, 1.7-cm isodense lesion, located between the mental foramen and masseter muscle, which was excised under general anesthesia. A well-defined cellular nodular mass was composed of bland spindle cells, in a densely vascularized, focally myxoid matrix, involving an arterial lumen, and extending into adjacent tissues. Mitoses were rare. Immunohistochemistry was positive for smooth muscle actin, negative for keratins, S-100, epithelial membrane antigen, caldesmon, p53 and Alk. CD31 and CD34 were positive only in the vascular component, supporting the diagnosis of intravascular fasciitis.

Resistance profiles of cyclic and linear inhibitors of HIV-1 protease

Resistance to anti-HIV protease drugs is a major problem in the design of AIDS drugs with long-term efficacy. To identify structural features associated with a certain resistance profile, the inhibitory properties of a series of symmetric and asymmetric cyclic sulfamide, cyclic urea and linear transition-state analogue inhibitors of HIV-1 protease were investigated using wild-type and mutant enzyme. To allow a detailed structure-inhibition analysis, enzyme with single, double, triple and quadruple combinations of G48V, V82A, 184V and L90M substitutions was used. Kinetic analysis of the mutants revealed that catalytic efficiency was 1-30% of that for the wild-type enzyme, a consequence of reduced kcat in all cases and an increased KM for all mutants except for the G48V enzyme. The overall structure-inhibitory profiles of the cyclic compounds were similar, and the inhibition of the V82A, 184V and G48V/L90M mutants were less efficient than of the wild-type enzyme. The greatest increase in Ki was generally observed for the 184V mutant and least for the G48V/L90M mutant, and additional combinations of mutations did not result in improved inhibition profiles for the cyclic compounds. An extended analysis of additional mutants, and including a set of linear compounds, showed that the profile was unique for each compound, and did not reveal any general structural features associated with a certain inhibition profile. The effects of structural modifications in the inhibitors, or of mutations, were not additive and they differed depending on their context. The results demonstrate the difficulties in predicting resistance, even for closely related compounds, and designing compounds with improved resistance profiles.

Enigma of missing teeth in maxillofacial trauma

PURPOSE

The initial evaluation and treatment of trauma victims should follow a planned approach, as delineated by the Advanced Trauma Life Support protocol, with the main concern securing a patent airway. When trauma has been associated with maxillofacial injury, it can complicate airway management owing to aspirated avulsed teeth or dental prosthetic devices. In such cases, endotracheal intubation can be life-threatening, if the foreign bodies are pushed into the upper respiratory tract. The objective of the present report was to illustrate the diagnostic and management problems related to foreign bodies from the oral cavity lodged in the upper airway after blunt maxillofacial trauma or emergency endotracheal intubation. We also discussed how this could be prevented.

PATIENTS AND METHODS

A retrospective study was performed at the Department of Oral and Maxillofacial Surgery, Hadassah Medical Center (Jerusalem, Israel). The records of 1,411 patients admitted for treatment of facial trauma during the past 10 years were reviewed.

RESULTS

Of the 1,411 patients, 7 (0.5%) had aspirated foreign bodies that had lodged in the airway because of the trauma or subsequent intubation.

CONCLUSIONS

The patient's oral cavity and upper airway must be inspected thoroughly before attempting endotracheal intubation. Any foreign body should be removed from the mouth and throat. This process must be undertaken, despite the stressful and limiting conditions of emergency care.

A pedicled palatal periosteal flap for the closure of oro-antral fistula

Various surgical techniques have been developed for oro-antral fistula (OAF) closure, all of which have some drawback. Twenty consecutive patients with an OAF were enrolled in this prospective study. A trapezoid full-thickness flap extending from the palatal area to the buccal gingiva was raised, including the fistula at its centre. The palatal free end aspect was split into two layers and the deep periosteal layer was folded deep to the flap over the bony defect, thereby sealing the fistula. The superficial layer was returned to its primary position and sutured. The patients were followed for 3 months. Nineteen patients showed immediate OAF closure. One patient showed a residual oro-antral communication of 0.5mm in diameter that resolved spontaneously within 4 weeks. The pain level (on a visual analogue scale) was highest at the first follow-up week, with a mean score of 5.5, which decreased to a mean level of 2.5 in the second week and 0 in the fourth week. The mean satisfaction level was 9.85 on a scale of 0-10 (10 representing total satisfaction). The pedicled palatal periosteal flap is a simple and effective surgical technique with high predictability and patient satisfaction levels, offering one more alternative for the treatment of OAF.

A novel follicle-cell-dependent dominant female sterile allele, StarKojak, alters receptor tyrosine kinase signaling in Drosophila

We describe a new dominant allele, StarKojak, that alters receptor tyrosine kinase signaling in the follicle cells and in the eyes in Drosophila. We isolated StarKojak in a screen for follicle-cell-dependent dominant female sterile mutations. We show that StarKojak and revertants of StarKojak do not complement Star loss-of-function mutations. We propose that StarKojak is a novel type of allele of Star that has both dominant gain-of-function phenotypes early in development and dominant loss-of-function phenotypes later in development. Star encodes a putative transmembrane protein that has previously been shown to be a critical component of the epidermal growth factor receptor tyrosine kinase signaling pathway. Early in oogenesis, Star mRNA expression is higher in StarKojak egg chambers than in wild-type egg chambers, consistent with its gain-of-function phenotype. Later in oogenesis, Star mRNA expression is lower in StarKojak follicle cells than in wild-type follicle cells, consistent with its loss-of-function phenotype. By genetically analyzing StarKojak and its revertants, we present evidence that Star is involved in anterior-posterior axis formation both in the female germline cells and in the somatic follicle cells. We also demonstrate that at least part of the dominant female sterile phenotype of StarKojak is restricted to the posterior-pole follicle cells. We propose that Star functions by processing pro-Gurken to mature Gurken, which is thereby released in the region between the oocyte and the follicle cells and binds to the epidermal growth factor receptor in the follicle cells.

Salivary Gland Heterotopia, a Clinical and Pathological TNM Staging Challenge - Carcinoma ex Pleomorphic Adenoma Arising in a Parotid Lymph node

INTRODUCTION

Heterotopia is the presence of a particular tissue / tumor at a non-physiological / ectopic site. The study primary goals: To review the current data investigating heterotopic, normal appearing, and diseased salivary gland tumors, in lymph nodes. To describe the meticulous pathological investigation and multidisciplinary decision-making process of a heterotopic carcinoma ex pleomorphic adenoma arising in an intra-parotid lymph node.

MATERIALS AND METHODS

A literature search in the "PubMed" database using key words "carcinoma ex pleomorphic adenoma", "parotid lymph node", "salivary gland" and "heterotopia" was conducted. We describe the thorough pathological investigation and clinical decision-making process, focusing TNM staging system limitations.

RESULTS

A few case reports presented either normal appearing salivary tissue, benign tumors or low and high-grade salivary malignancies arising in lymph nodes. We present the investigation, controversies and treatment decision process of a 46-year-old man with CXPA in intra-parotid lymph node.

CONCLUSIONS

The staging scheme does not distinguish between nodal spread and primary tumor arising in a lymph node. Multidisciplinary input regarding prognosis and follow-up plans, may consider heterotopia differently from the usual pattern of nodal spread.

Short Dental Implants (5 to 7 mm) with Expandable Apex in the Posterior Maxilla-Preliminary Results

PURPOSE

The purpose of this study was to examine whether the use of short dental implants with an expandable compressive design could be a proper alternative to the conventional sinus elevation procedure in cases of deficient alveolar ridge height in the posterior maxillary area.

MATERIALS AND METHODS

Fifty patients with 73 short dental implants with an expandable compressive design who were treated for posterior maxillary alveolar ridges of 5 to 7 mm in the vertical dimension between 2012 and 2018 were included in a retrospective study. All patients had a minimum postrehabilitation period of 1 year. Patient demographics, implant properties, primary stability, and implant success and survival rates were analyzed.

RESULTS

The total success rate was 97.2%, with two failed implants at implant uncovering. The mean bone loss was 1.03 mm. No difference in bone loss was found between sexes or age groups.

CONCLUSION

The results of this study suggest that short dental implants with an expandable apical compressive design could be an alternative to sinus elevation procedures in selected cases of vertically deficient maxillary alveolar ridges.