Retrospective evaluation of a dose-dependent effect of angiotensin-converting enzyme inhibitors on long-term outcome in dogs with cardiac disease

Background

Angiotensin‐converting enzyme inhibitors (ACEIs) are commonly prescribed in dogs, but the ideal dosage is unknown.

Hypothesis/Objectives

In dogs with cardiac disease, a dose‐response relationship exists for ACEIs with respect to long‐term outcome.

Animals

One hundred forty‐four dogs with cardiac disease, 63 with current or prior congestive heart failure.

Methods

Retrospective medical record review. Cox proportional hazards models were used to determine variables associated with 2‐year survival or survival from first‐onset congestive heart failure (CHF).

Results

Median initial ACEI dosage was 0.84 (interquartile range [IQR], 0.56‐0.98) mg/kg/day, and 108/144 (75%) of dogs received q12h dosing. No clinically relevant changes in renal function test results, serum electrolyte concentrations, or blood pressure occurred between initial prescription of ACEI and first reevaluation (median, 14 days later). In univariable analysis, higher ACEI dose was associated with increased survival from first‐onset CHF (P = .005), and within the subgroup of dogs in CHF at the time of ACEI prescription, higher ACEI dose was associated with improved survival at 2 years (P = .04). In multivariable analysis, q12h dose frequency of ACEI (hazard ratio [HR], 0.30; 95% CI, 0.10‐0.88; P = .03) and higher serum potassium concentration at visit 1 (HR, 0.39; 95% CI, 0.16‐0.97; P = .04) were predictive of 2‐year survival. The ACEIs were well‐tolerated, with only 8/144 (5.6%) dogs having ACEI dose decreased or discontinued because of adverse effects.

Conclusions and Clinical Importance

Twice daily dose frequency might optimize the cardioprotective benefit of ACEIs.

Focused ultrasound of the caudal vena cava in dogs with cavitary effusions or congestive heart failure: A prospective, observational study

INTRODUCTION

Ultrasonographic indices of the inferior vena cava are useful for predicting right heart filling pressures in people.

OBJECTIVES

To determine whether ultrasonographic indices of caudal vena cava (CVC) differ between dogs with right-sided CHF (R-CHF), left-sided CHF (L-CHF), and noncardiac causes of cavitary effusion (NC).

MATERIALS AND METHODS

113 dogs diagnosed with R-CHF (n = 51), L-CHF (30), or NC effusion (32) were enrolled. Seventeen of the R-CHF dogs had pericardial effusion and tamponade. Focused ultrasound was performed prospectively to obtain 2-dimensional and M-mode subxiphoid measures of CVC maximal and minimal size (CVCmax and CVCmin), CVCmax indexed to aortic dimension (CVC:Ao), and CVC collapsibility index (CVC-CI). Variables were compared between study groups using Kruskal-Wallis and Dunn's-Bonferroni testing, and receiver operating characteristics curves were used to assess sensitivity and specificity.

RESULTS

All sonographic CVC indices were significantly different between R-CHF and NC dogs (P < 0.001). Variables demonstrating the highest diagnostic accuracy for discriminating R-CHF versus NC were CVC-CI <33% in 2D (91% sensitive and 96% specific) and presence of hepatic venous distension (84% sensitive and 90% specific). L-CHF dogs had higher CVC:Ao and lower CVC-CI compared to NC dogs (P = 0.016 and P = 0.043 in 2D, respectively) but increased CVC-CI compared to the R-CHF group (P < 0.001).

CONCLUSIONS

Ultrasonographic indices of CVC size and collapsibility differed between dogs with R-CHF compared to NC causes of cavitary effusions. Dogs with L-CHF have CVC measurements intermediate between R-CHF and NC dogs.

[Optic nerve morphology and vessel density in eyes with different phases of non-arteritic anterior ischemic optic neuropathy]

Objective: To compare the blood flow around the optic disc and related factors in patients with acute and chronic non-arteritic anterior ischemic optic neuropathy (NAION) and healthy volunteers with small disc cups under the same anatomical structure. Methods: This was a prospective case-control study. NAION patients with unilateral onset and healthy volunteers of the same phase were included in the study conducted at the Department of Ophthalmology of Peking Union Medical College Hospital between February 2017 and September 2018. Patients with a course of ≤ 3 months were categorized in the acute phase of NAION, and those with a course of >3 months were in the chronic phase of NAION. Healthy volunteers were in the control group. All subjects underwent the examination of best corrected visual acuity converted to logarithm of the minimum angle of resolution (LogMAR), measurement of non-contact intraocular pressure, slit lamp examination, small pupil fundus examination, and axial measurement. Optical coherence tomography was used to measure the thickness of retinal nerve fiber layers (RNFL) and retinal ganglion cell complex (GCC). Optical coherence tomography angiography was used to measure the vessel density around the optic disc. NAION patients underwent the visual field examination. Analysis of variance, non-parametric Mann-Whitney U test and Spearman coefficient was used for statistical analysis. Results: This study included 16 patients with acute phase of NAION, aged (57±9) years, 6 males and 10 females. There were 17 patients with chronic disease, aged (56±10) years, 7 males and 10 females. There were 15 healthy controls, aged (57±10) years old, 6 males and 9 females. There were no significant differences in age and gender between the groups (both P>0.05). The RNFL and the GCC in the NAION chronic phase group were significantly thinner than those in the acute phase group [(78±38) μm vs. (191±99) μm, (75±19) μm vs. (98±28) μm; t=4.389, 2.758; both P<0.05]. The cup/disc area ratio, cup/disc vertical diameter ratio and cup/disc horizontal diameter ratio in the chronic phase group were larger than those in the acute phase group [0.18 (0.11, 0.31) vs. 0.05 (0.01, 0.18), 0.45 (0.39, 0.56) vs. 0.22 (0.11, 0.41), 0.39 (0.28, 0.54) vs. 0.20 (0.07, 0.42)], and the difference was statistically significant (U=212.000, 208.000, 205.000; all P<0.05). Compared with the optic disc vessel density in the control group (53%±6%), there was a significant decrease in the acute phase group and the chronic phase group (45%±7%, 41%±8%; t=3.705, 4.940; both P<0.01). The blood vessel density in the nasal inferior of the chronic phase group was significantly lower than that in the acute phase group (36%±8% vs. 42%±7%, P=0.039), other sections didn't have significant difference (all P>0.05). There were tortuous capillaries in 8/16 of the acute phase cases, with a low blood flow density and visual field defect in relative positions. Correlation analysis showed that the whole density and peripapillary density in the NAION patients were negatively correlated with LogMAR, mean visual field defect, cup/disc area ratio, focal loss of volume of GCC and general loss of volume of GCC (r=-0.510, -0.733, -0.372, -0.532, -0.648; all P<0.01), but positively correlated with GCC and RNFL thickness (r=0.604, 0.508; both P<0.01). Conclusions: The optic disc vessel density in the acute phase and chronic phase of NAION is significantly reduced. The vessel density in the nasal area of the chronic phase is significantly reduced compared with the acute phase. The vessel density is correlated with visual acuity, visual field defect, disc indexes, thickness of RNFL and GCC. (Chin J Ophthalmol, 2019, 55: 677-686).

[Vessel density and structure in the macular region of non-arteritic anterior ischemic optic neuropathy patients]

Objective: To explore the correlation between the vessel density and the structure and visual function in patients with non-arteritic anterior ischemic optic neuropathy (NAION) in different stages. Methods: This case-control study included 25 NAION patients (28 eyes)of Peking Union Medical College Hospital from November 2017 to May 2018 and 25 healthy controls(HC) (25 eyes) of matched age and gender. General eye examination, visual field examination, and optical coherence tomography angiography were performed to obtain data of blood flow in the macular area and structure such as ganglion cell complex (GCC) and gross loss of volume (GLV), and focal loss of volume (FLV). All affected eyes were divided into the acute group (≤3 weeks), sub-acute group (4 to 12 weeks), and chronic group (>12 weeks) in line with the course of the disease. The group and regional analyses were made to carry out overall differences of blood flows and structures and the correlations with visual function. Results: There were 25 NAION patients with 28 eyes, 16 males and 9 females, aged (55±9) years. The acute group included 8 patients (8 eyes), and the sub-acute group included 10 patients (10 eyes), while the chronic group comprised 7 patients (10 eyes). The overall macular superficial vessel density of patients with NAION was significantly reduced compared with the HC(42.03%±5.70% vs.49.01%±3.34%, t=-5.546, P<0.01), but the deep vessel density was not significantly reduced (P>0.05). The superficial vessel density of the acute group, sub-acute group, and chronic group was significantly decreased(47.41%±3.51% vs. 41.68%±3.09% vs.38.06%±5.93%, all P<0.05). The GCC thickness in patients with NAION were significantly lower than the HC [(88.5±18.2) μm vs. (102.9±5.4)μm, P<0.05]. The GLV and FLV in patients with NAION were significantly higher than the HC (12.733%±11.216% vs. 0.941%±0.852%, 6.295%±4.291% vs. 0.596%±0.460%, both P<0.05). There was a correlation between the macular superficial vessel density and GCC thickness (r=0.606, P=0.001), FLV(r=-0.552, P=0.002), GLV (r=-0.685, P=0.000) and mean sensitivity (r=0.493, P=0.023). Conclusion: Compared with healthy controls, the macular superficial vessel density in NAION patients decreas along with the course of the disease, and its correlation with structural and visual function is revealed. (Chin J Ophthalmol, 2019, 55:195-202).

Electro-optically spectrum narrowed, multiline intracavity optical parametric oscillators

We report on the first building of an active spectral narrowing mechanism in a pulsed, multiline optical parametric oscillator (OPO) based on a novel aperiodically poled lithium niobate (APPLN) device constructed using the aperiodic optical superlattice technique. The APPLN device functions simultaneously in the system as a multi-channel optical parametric down converter (OPDC) and an electro-optic (EO) gain spectral filter working on the corresponding (multiple) signal bands. When the APPLN OPO was installed in a diode pumped Nd:YVO₄ laser system, highly narrowed dual-wavelength signal lines (at 1540 and 1550 nm) were observed at the output of the system through EO control of the APPLN. Correspondingly, an enhancement of the power spectral density of the source by a factor of ~7.8 with respect to the system operated in passive mode was found.

Experimental and simulation studies of anti-reflection sub-micron conical structures on a GaAs substrate

In order to reduce surface reflection, anti-reflective (AR) coatings are widely used on the surfaces of solar cells to improve the efficiency of photoelectric conversion. This study employed colloidal lithography with a dry etching process to fabricate sub-micron anti-reflection structures on a GaAs substrate. Etching parameters, such as RF power and etching gas were investigated to determine their influence on surface morphology. We fabricated an array of conical structures 550 nm in diameter and 450 nm in height. The average reflectance of a bare GaAs wafer was reduced from 35.0% to 2.3% across a spectral range of 300 nm - 1200 nm. The anti-reflective performance of SWSs was also calculated using Rigorous Coupled Wave Analysis (RCWA) method. Both simulation and experiment results demonstrate a high degree of similarity.

Fabrication of high-refractive-index microstructures and their applications to the efficiency improvement of GaN-based LEDs

This study employed a UV-assisted roller imprinting technique using PDMS soft molds to imprint periodically inverted-pyramid structures on the surface of GaN-based LEDs. The refractive indices of the structures were 1.5, 1.7, and 1.9, which enhanced light output power by 26%, 43%, and 50%, respectively, compared to conventional LEDs. Materials with a greater refractive index indicate a larger critical angle of total internal reflection from the semi-conductor to the imprinted material. Once photons are extracted into the imprinted structure, they are prone to be extracted into the air through the structured surface. The numerical simulation performed using the ray tracing method proved useful for identifying the microstructure with optimal light extraction efficiency. Simulation results showed that LEDs with imprinted structures of varying refractive indices enhance optical efficiency in a manner similar to that demonstrated in these experiments.

Generalized tensor-based morphometry of HIV/AIDS using multivariate statistics on deformation tensors

This paper investigates the performance of a new multivariate method for tensor-based morphometry (TBM). Statistics on Riemannian manifolds are developed that exploit the full information in deformation tensor fields. In TBM, multiple brain images are warped to a common neuroanatomical template via 3-D nonlinear registration; the resulting deformation fields are analyzed statistically to identify group differences in anatomy. Rather than study the Jacobian determinant (volume expansion factor) of these deformations, as is common, we retain the full deformation tensors and apply a manifold version of Hotelling's $T(2) test to them, in a Log-Euclidean domain. In 2-D and 3-D magnetic resonance imaging (MRI) data from 26 HIV/AIDS patients and 14 matched healthy subjects, we compared multivariate tensor analysis versus univariate tests of simpler tensor-derived indices: the Jacobian determinant, the trace, geodesic anisotropy, and eigenvalues of the deformation tensor, and the angle of rotation of its eigenvectors. We detected consistent, but more extensive patterns of structural abnormalities, with multivariate tests on the full tensor manifold. Their improved power was established by analyzing cumulative p-value plots using false discovery rate (FDR) methods, appropriately controlling for false positives. This increased detection sensitivity may empower drug trials and large-scale studies of disease that use tensor-based morphometry.

Giant enhancement of band edge emission based on ZnO/TiO(2) nanocomposites

Enhancement of band edge emission of ZnO nanorods up to a factor of 120 times has been observed in the composite consisting of ZnO nanorods and TiO(2) nanoparticles, while the defect emission of ZnO nanorods is quenched to noise level. Through a detailed investigation, it is found that the large enhancement mainly arises from fluorescence resonance energy transfer between the band edge transition of ZnO nanorods and TiO(2) nanoparticles. Our finding opens up new possibilities for the creation of highly efficient solid state emitters.

Enhancement of band gap emission stimulated by defect loss

Defect radiation has been always considered as the most important loss for an emitter based on band gap emission. Here, we propose a novel approach which goes against this conventional wisdom. Based on the resonance effect between the surface plasmon of metal nanoparticles and defect emission, it is possible to convert the useless defect radiation to the useful excitonic emission with a giant enhancement factor. Through the transfer of the energetic electrons excited by surface plasmon from metal nanoparticles to the conduction band of the emitter, the band gap emission can be greatly enhanced, while the defect emission can be suppressed to noise level.

p53 and p21 expression in precancerous lesions and carcinomas of the uterine cervix: overexpression of p53 predicts poor disease outcome

OBJECTIVES

Abnormal expression of the p53 and p21(waf1/cip1) tumor suppressor genes has been observed in a variety of human tumors, but little is known about its expression during cervical tumorigenesis. To identify the potential implications of both genes in the development of cervical carcinoma and explore the clinical importance of changes in gene expression, we assessed the levels of both proteins in precancerous lesions and carcinomas of the cervix.

METHODS

In our study, 10 low-grade squamous intraepithelial lesions (LSIL), 35 high-grade squamous intraepithelial lesions (HSIL), 12 microinvasive carcinomas, and 103 invasive carcinomas were evaluated. The expression of p53 and p21 was studied by immunohistochemistry using monoclonal antibodies specific for these proteins.

RESULTS

p21 was expressed in all samples of normal epithelium, LSIL, and HSIL, and the mean values of expression were 50.3, 42.5, and 44.5%, respectively. Conversely, the expression of p21 was significantly reduced in microinvasive (30.7%) and invasive carcinomas (9.9%). p53 nuclear staining was not detected in normal epithelium samples or LSILs, while 4 (11.4%) of 35 HSILs, 1 (8.3%) of 12 microinvasive carcinomas, and 38 (36.9%) of 103 invasive carcinomas were positive for p53. Compared with the results of the control group, precancerous lesions, and microinvasive carcinoma, the mean value of p53 expression (4.8%) in invasive carcinoma was significantly higher. Furthermore, p53 overexpression was significantly associated with advanced stage of the tumor (P < 0.001) [16/67 (23.9%) stage I, 15/28 (53.6%) stage II, and 7/8 (87.5%) stage III/IV]. In univariate analysis, p53 overexpression was a significant predictor of poor survival, whereas it had no independent influence on overall survival using the Cox regression method. Our data also revealed that no association between p53 immunostaining and p21 expression was found.

CONCLUSIONS

The trend of reduced p21 expression in microinvasive and invasive carcinomas suggests that p21 may play a tumor-suppressor function in neoplastic transformation in cervical epithelium and inactivation of p21 may be an early event in cervical carcinogenesis. Our results indicated that p53 overexpression was a significant predictor of poor disease outcome in univariate analysis. Moreover, significantly increased expression of p53 in advanced-stage cervical carcinoma implies that inactivation of p53 is associated with tumor progression. Finally, this study further supports the notion that induction of p21 expression can be regulated in a p53-independent manner.

An analysis of excitatory amino acids, nitric oxide, and prostaglandin E2 in the cerebrospinal fluid of pregnant women: the effect on labor pain

It is still unclear which neurotransmitters are involved in labor pain. We measured the concentrations of excitatory amino acids, nitric oxide, and prostaglandin E2 in the cerebrospinal fluid (CSF) of pregnant women, particularly in those with labor pain. The patients included in the study consisted of women who underwent cesarean delivery either with labor pain (Labor Pain group, n = 40) or without labor pain (Nonlabor Pain group, n = 58). All patients received spinal anesthesia (intrathecal injection of 10-12 mg of bupivacaine) for the operation, and 2 mL of CSF was collected before bupivacaine injection. Concentrations of aspartate and glutamate (0.50 +/- 0.06 microM and 0.79 +/- 0.10 microM, respectively) were significantly larger in the Labor Pain group than in the Nonlabor Pain group (0.35 +/- 0.03 microM and 0.54 +/- 0.04 microM, P < 0.05). There were no significant differences in the concentrations of nitric oxide and prostaglandin E2 between the groups. A positive correlation was found between CSF concentrations of excitatory amino acids and labor pain.

IMPLICATIONS

The excitatory amino acids, aspartate and glutamate, play a role in labor pain. N-methyl-D-aspartate receptor antagonists may be useful for labor pain and postlabor uterine contraction pain relief.

Isolated fetal and neonatal ascites: report of two cases

Neonatal ascites is an uncommon problem that may be caused by a number of etiologies including diseases of genitourinary system and gastrointestinal system, cardiac disease, hepatic disease, systemic infection such as TORCH or parvovirus, chylous, ovarian cause, inborn error of metabolism and idiopathic. We reported two cases of neonatal ascites, one was caused by cytomegalovirus and no obvious causes could be detected in the second one. The ascites were diagnosed by prenatal ultrasound at the gestational age of 25 weeks and 37 weeks respectively and were resolved spontaneously after birth. One-year follow-up of both cases revealed normal growth and development. No recurrent ascites could be detected by abdominal sonography except for evidence of mild hepatomegaly that was noted in case 1. Thus, isolated fetal and neonatal ascites without other concomitant abnormalities were diagnosed, a separate entity from non-immune hydrops fetalis with excellent prognosis.

Intrathecal cyclooxygenase inhibitor administration attenuates morphine antinociceptive tolerance in rats

Several lines of evidence suggest that the N-methyl-D-aspartate receptor (NMDA) and nitric oxide (NO) systems are involved in morphine tolerance. Cyclooxygenase (COX) inhibitors may also play a role in morphine tolerance by interacting with both systems. In the present study, we examined the effects of the COX inhibitors N-(2-cyclohexyloxy-4-nitrophenyl) methanesulphonamide (NS-398, selective COX2 inhibitor) and indomethacin (non-selective COX inhibitor) on the development of antinociceptive tolerance of morphine in a rat spinal model. The antinociceptive effect was determined by the tail-flick test. Tolerance was induced by injection of morphine 50 micrograms intrathecally (i.t.) twice daily for 5 days. The effects of NS-398 and indomethacin on morphine antinociceptive tolerance were examined after administering these drugs i.t. 10 min before each morphine injection. Neither NS-398 nor indomethacin alone produced an antinociception effect at doses up to 40 micrograms. NS-398 and indomethacin did not enhance the antinociceptive effect of morphine in naïve and morphine-tolerant rats. However, they shifted the morphine antinociceptive dose-response curve to the left when coadministered with morphine during tolerance induction, and reduced the increase in the ED50 of morphine (dose producing 50% of the maximum response) three- to four-fold. Collectively, these findings and previous studies suggest that COX may be involved in the development of morphine tolerance without directly enhancing its antinociceptive effect.

Morphine tolerance increases [3H]MK-801 binding affinity and constitutive neuronal nitric oxide synthase expression in rat spinal cord

N-Methyl-D-aspartate (NMDA) receptor antagonists and nitric oxide synthase (NOS) inhibitors inhibit morphine tolerance. In the present study, a lumbar subarachnoid polyethylene (PE10) catheter was implanted for drug administration to study alterations in NMDA receptor activity and NOS protein expression in a morphine-tolerant rat spinal model. Antinociceptive tolerance was induced by intrathecal (i.t.) morphine infusion (10 micrograms h-1) for 5 days. Co-administered (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801) (10 micrograms h-1 i.t.) with morphine was used to inhibit the development of morphine tolerance. Lumbar spinal cord segments were removed and prepared for [3H]MK-801 binding assays and NOS western blotting. The binding affinity of [3H]MK-801 was higher in spinal cords of morphine-tolerant rats (mean (SEM) KD = 0.41 (0.09) nM) than in control rats (1.50 (0.13) nM). There was no difference in Bmax. Western blot analysis showed that constitutive expression of neuronal NOS (nNOS) protein in the morphine-tolerant group was twice that in the control group. This up-regulation was partially prevented by MK-801. The results suggest that morphine tolerance affects NMDA receptor binding activity and increases nNOS expression in the rat spinal cord.

Atypical central neurocytoma: report of a case

Central neurocytomas are rare, relatively benign intraventricular neoplasms composed of uniform round cells with neuronal differentiation. The majority of previously reported central neurocytomas did not recurr after tumor removal and the patients had favorable postoperative outcomes. Only a few cases with malignant histopathology or malignant behavior have been noted. Atypical central neurocytoma is a new entity that was first described in the literature in 1997. The tumors have been noted to exhibit a Ki-67 labeling index of 2% or more, or vascular proliferation, mitoses, and necrosis, or both. Atypical histologic findings are usually associated with a somewhat less favorable clinical course and requires postoperative radiotherapy. We report a unique case of a 33-year-old man with a large intraventricular central neurocytoma. The characteristic histopathologic picture, the immunoreactivity for both synaptophysin and neuron-specific enolase, and the ultrastructural features of neuronal differentiation distinguished it from ependymoma and oligodendroglioma. The mitotic activity (up to 3 mitoses/10 high power field) and the high percentage of Ki-67-staining tumor cells (labeling index, 5.0%) in our case were consistent with the atypical variant of central neurocytoma. The patient underwent craniotomy and partial resection of the tumor. Unfortunately, he died of hydrocephalus and brain edema, the next day.

Ultrastructural and biochemical characterization of catecholamine release mechanisms in cultured human pheochromocytoma cells

OBJECTIVE

To characterize ultrastructurally and biochemically catecholamine release mechanisms of cultured human pheochromocytoma cells in the basal and stimulated states.

METHODS

The cultured pheochromocytoma cells were prepared from human adrenal pheochromocytoma tumors. Biochemical determinations of catecholamine secretion from the cultured cells were carried out in the basal and stimulated states. Transmission electron microscopy was used to observe the modes of catecholamine release from the cells without and with stimulation by depolarization of the cells with the administration of 50 mmol/L KCl.

RESULTS

Biochemical determinations consistently showed spontaneous secretion of catecholamines from the cultured cells in the basal state without stimulation. Catecholamine release in a calcium-dependent manner could be enhanced in the cells in response to high extracellular potassium concentration. A series of electron microscopic observations of the cultured cells consistently disclosed the classical exocytotic profiles on the cell surface in the basal state. In addition to abundant increase in the number of classical single exocytosis, compound exocytosis was frequently observed in the stimulated cells. Furthermore, other modes of catecholamine release mechanism involving the formation of pseudopodial and/or tubule-like structures, which were different from classical exocytosis, were often present in the intensely stimulation cells.

CONCLUSIONS

Based on the biochemical and electron microscopic findings, we concluded: (1) classical single exocytosis is considered to be a primary mechanism responsible for spontaneous secretion of catecholamines from the cells in the basal state; (2) compound exocytosis is an essential mechanism for extruding large amounts of catecholamines in the stimulated cells; and (3) other modes of catecholamine release mechanism may operate in the cells in response to intense stimulation. These morphological data may be helpful in explanation of biochemical variability and extreme diversity of clinical manifestations in patients with pheochromocytoma tumor.

Pathogenetic mechanism of senile calcific aortic stenosis: the role of apoptosis

OBJECTIVE

To investigate the pathogenetic mechanisms leading to the development of calcific degeneration of the aortic valve in the elderly patients with particular reference to the relationship between apoptosis and calcification in the aortic valve tissue.

METHODS

High resolution scanning and transmission electron microscopic observations of the calcified aortic valves obtained during aortic valve replacement were carried out in 10 patients with senile calcific aortic stenosis.

RESULTS

Various degrees of endothelial alterations from focal disruption of individual endothelial cells to extensive denudation of entire endothelium were observed particularly on the aortic side of the valve tissues. The apoptotic changes occurring in the nuclei of endothelial cells and fibroblasts were common findings in the calcified valve tissues. It was noteworthy that the severity of endothelial damage was closely related to apoptotic changes of the fibroblasts. Calcific deposits were frequently observed in association with the cellular fragments mainly derived from the apoptotic fibroblasts.

CONCLUSIONS

Our results strongly indicate that apoptosis may play an important role in the alterations of endothelial integrity leading to the increased filtration of calcium into the deeper layer of the valve tissues. Then, the cellular degradation products and organelles extruded from the dead cells, mainly resulted from apoptosis provided the substrates for calcium binding with progressive development of calcification in the valve tissue. Although the role of apoptosis in contribution to the pathogenesis of senile calcific aortic stenosis is evident, further studies using modern molecular biotechnology are mandatory in order to clarify the mechanism for the initiation of apoptotic process in the endothelial cells and fibroblasts.

Electron microscopic studies of microvasculature and sympathetic nerve fibers in dilated cardiomyopathy

OBJECTIVE

To investigate the ultrastructural pathological alterations of the microvasculature and nerve fibers in the endomyocardial biopsied specimens of the left ventricular myocardium obtained from patients with idiopathic dilated cardiomyopathy and chronic heart failure.

METHODS

Transmission electron microscopic observations of endomyocardial biopsied specimens of the left ventricular myocardium were carried out in 10 patients with idiopathic dilated cardiomyopathy and chronic heart failure.

RESULTS

Various degrees of ultrastructural pathological alterations in the microvessels and sympathetic nerves in the diseased myocardium were consistently demonstrated in idiopathic dilated cardiomyopathy. In addition, abnormal accumulation of collagen tissue and edematous fluid were often seen in the interspace between myocardial cells and nerve endings and capillaries.

CONCLUSIONS

Based on the ultrastructural pathological findings in this study, we consider that all the structures forming the muscle cells and the tissues around them, namely the microvessels and nerves may participate in the pathological process in the course of dilated cardiomyopathy. The damage of microvasculature and sympathetic nerves resulting from the underlying disease processes are considered to be an important pathogenetic mechanism responsible for progressive development of myocardial degeneration and dysfunction throughout the course of the disease. It is hoped that our data may provide some insights into the understanding of the role of microcirculation and sympathetic nerves in the etiopathogenesis of dilated cardiomyopathy.

Electron microscopic observations of apoptotic cells in various etiologies of human cardiovascular diseases

OBJECTIVE

To observe apoptotic process in various cardiovascular disorders with a particular attention to the ultrastructural morphology of apoptosis in cardiomyocytes, fibroblasts, vascular endothelial cells and smooth muscle cells.

METHODS

Transmission electron microscopic observations of the tissue specimens obtained from endomyocardial biopsies or surgical excisions of left ventricular myocardium or calcified aortic valves were carried out in 50 patients with various cardiovascular diseases.

RESULTS

The ultrastructural features of apoptosis was consistently observed in cardiomyocytes, fibroblasts, vascular endothelial cells and smooth muscle cells in all diseased tissues. In cardiomyopathies and rheumatic heart diseases apoptosis was commonly observed in the cardiomyocytes. It was often found that fibroblasts underwent apoptosis in calcific aortic valve tissues. Apoptosis of arterial smooth muscle cells was a frequent finding in renal arterial stenosis due to Takayasu's arteritis and fibromuscular dysplasia. Regardless of the cell types, the nuclear hallmarks of apoptosis were identical with minor modifications of the fragmentation of the condensed cells into apoptotic bodies.

CONCLUSIONS

Based on electron microscopic findings, it is suggested that the underlying disease processes determine which type of cells predominantly undergoes apoptotic changes in various cardiovascular disorders. In addition, different cells with similar structural morphology may have common ultrastructural features of apoptosis.

Molecular level investigation of exocytosis in cultured human pheochromocytoma cells: insights from high resolution scanning electron microscopy combined with autoradiogram and cytochemistry

OBJECTIVE

To investigate molecular events of exocytosis in cultured human pheochromocytoma cells with stimulation.

METHODS

The cultured pheochromocytoma cells prepared from human adrenal pheochromocytoma tumor were stimulated for the release of catecholamines by depolarization with the administration of 50 mmol/L KCl. Transmission electron microscopy (TEM) and high resolution scanning electron microscopy (HR-SEM) combined with autoradiography and cytochemistry were used to observe molecular mechanisms of exocytotic release of catecholamines from the stimulated cells labelled with 3H-noradrenaline and the filipin-treated cells.

RESULTS

TEM and HR-SEM observations of the stimulated cells labelled with 3H-noradrenaline revealed that the initial exocytotic fusion pores even less than 10 nm in diameter in human pheochromocytoma cells can be clearly observed in a single lipid bilayer. Furthermore, HR-SEM examinations of the filipin-treated cells showed that the derangement of the particles of the filipin-sterol complexes (FSCs) in the fused membranes of granule and plasma membranes occurred as the exocytotic fusion pores opened. In addition, the aggreates of the FSCs particles were consistently demonstrated around the openings of the differently sized closing exocytotic pores.

CONCLUSIONS

Based on our results, it is suggested that the rearrangement of the sterol molecules in the fused membranes of granule and plasma membranes plays an important role in the opening and closing mechanisms of exocytotic fusion pores. We hope that morphological data obtained in this study can provide some new insights into the understanding of molecular mechanisms of exocytosis, particularly the opening and closing of exocytotic fusion pores in relation to the distribution of the membrane sterols.

Endothelial alterations and senile calcific aortic stenosis: an electron microscopic observation

Calcific degeneration of aortic valves were investigated in 10 patients with senile calcific aortic stenosis by means of high resolution scanning electron microscopy (HR-SEM) and transmission electron microscopy (TEM). All the specimens obtained during aortic valve surgery HR-SEM and TEM examinations consistently showed various degrees of pathological alterations and calcification involving surface endothelium, underlying basement membranes and deeper layers of interweaving networks of collagen fiber bundles in the pars fibrosa of the valve tissues. Calcific deposits in the valve tissues always occurred in the vicinity of the endothelial defects and in the subendothelial structures just beneath the defective endothelium. The amount of calcific deposits in the valve tissues increased in proportion to the severity of endothelial damage and gradually decreased from the defective endothelial surface to the deeper layer of collagen tissue. In addition, apoptotic cell death, particularly of the fibrocytes in the valve tissue, was closely related to the severity of endothelial injury. Cellular fragments derived from the apoptotic cells were always associated with calcium deposits. Based on the above findings, our results provide evidence that the alteration of endothelial integrity plays a contributory role in calcific degeneration in the aortic valve leading to the development of senile calcific aortic stenosis.

Expression of P-glycoprotein and p53 in advanced hepatocellular carcinoma treated by single agent chemotherapy: clinical correlation

Hepatocellular carcinoma (HCC), a chemoresistant tumour, is the most common fatal cancer in Taiwan. Hepatocellular carcinoma frequently expresses a high level of P-glycoprotein (P-gp), which is a specific phenotype of a multidrug-resistance gene, and harbours mutations of the tumour suppressor gene p53. A modulatory relationship between p53 and P-gp has been reported. In this study, we analysed the expression of P-gp in relation to chemotherapeutic response and p5353 protein expression in advanced HCC. Prechemotherapeutic tumour samples were obtained from 25 patients with HCC which had been treated with either etoposide (VP-16) or doxorubicin. P-glycoprotein and p53 in HCC were visualized by immunohistochemical staining using the monoclonal antibodies JSB-1 and DO1, respectively. We investigated the correlation of P-gp expression with chemotherapeutic responses, clinicopathological features and p53 protein expression. In our study, seven cases achieved partial remission, and the remaining 18 cases had a poor response to chemotherapy. Expression of P-gp was observed in 13 tumours (52%). Positive P-gp protein expression was significantly associated with non-responders (8% or 1/13 vs 50% or 6/12, P = 0.03). Thus, P-gp expression inversely correlated with chemotherapeutic response. Expression of p53 protein was seen in 12 cases and did not correlate with chemosensitivity or P-gp expression. In summary, P-gp expression correlates with the chemosensitivity of HCC that has been treated with VP-16 or doxorubicin and p 53 mutations do not appear to be a major determinant of P-gp expression in advanced HCC.

Continuous antegrade warm blood cardioplegia attenuates augmented coronary endothelium-dependent contraction after cardiac global ischemia and reperfusion

BACKGROUND

Experiments were designed to evaluate the effect of warm blood cardioplegia on endothelium-dependent contraction of the coronary endothelium after cardiac global ischemia and reperfusion.

METHOD

Dogs (n = 12 in each group) were exposed to extracorporeal circulation with the body temperature at 37 degrees C (group 1) or 28 degrees C (groups 2 and 3). The ascending aorta was crossclamped for 120 minutes while continuous infusion of warm blood cardioplegec solution (group 1) or intermittent infusion of cold (4 degrees C) crystalloid cardioplegic solution (group 2) was performed via the coronary arteries through the aortic root. Cardioplegic solution was not used in group 3 animals. The heart was then allowed to function for 60 minutes of reperfusion. Reperfused (groups 1, 2, and 3) and control (group 4) coronary arteries were then harvested for study.

RESULTS

Perfusate hypoxia caused endothelium-dependent contraction in the arteries of all four groups that could be attenuated by NG-monomethyl-L-arginine (L-NMMA) or L-NMMA plus D-arginine, but not by L-NMMA plus L-arginine or endothelin receptor A and B antagonist PD 145065. The endothelium-dependent contraction results in groups 2 and 3 (75% +/- 4% and 80% +/- 5%, respectively) were significantly greater than those in groups 1 and 4 (15% +/- 3% and 18% +/- 5%, respectively). Scanning electron microscope studies showed that platelet adhesion and aggregation, areas of microthrombi, disruption of endothelial cells, and separation of the intercellular junction could be found in coronary segments from groups 2 and 3, but not in vessels from groups 1 and 4.

CONCLUSION

These experiments suggest that global ischemia and reperfusion enhances hypoxia-mediated endothelium-dependent contraction of the coronary endothelium and damages the ultrastructure. These kinds of changes can be prevented by continuous antegrade infusion of warm blood cardioplegic solution during global ischemia.

Case report: primary cystic keratinizing squamous cell carcinoma of the liver in a patient with treated nasopharyngeal carcinoma

Primary squamous cell carcinoma of the liver is very rare; only 18 cases have been recorded. In the present report we document an additional case who had a unique history of stage III non-keratinizing nasopharyngeal carcinoma treated with a full course of radiotherapy in July 1993. Two small hypoechoic cyst-like lesions in the left hepatic lobe were identified at the same time. In July 1995 the 50-year-old patient reported to be suffering from abdominal fullness and tenderness. A large hypodense tumour was demonstrated in the left hepatic lobe by abdominal echography. The patient was diagnosed as having metastatic carcinoma and received two courses of pre-operative chemotherapy followed by left lobectomy of the liver and resection of adherent tissues on 9 August 1995. Pathological study demonstrated a larger hepatic cystic keratinizing squamous cell carcinoma, which most likely arose from a solitary hepatic cyst. Tumour seedings, probably secondary to tumour rupture, were also revealed on the omentum, peritoneum and diaphragm. However, regional lymph nodes were fee of tumour. Systemic work-up failed to demonstrate evidence of local recurrence of nasopharyngeal carcinoma, metastatic lesion or any second primary tumour site.

Primary ovarian carcinoid tumor

Pure primary ovarian carcinoid tumors are uncommon and only 21 cases have been recorded in the literature. In the past 15 years, we have seen two cases. One was a strumal carcinoid and the other, the case presented here, was a primary ovarian carcinoid tumor arising from the left ovary of a 25-year-old woman who had no carcinoid syndrome. The tumor was made up of pure carcinoid tumor without other teratomatous elements. On light microscopy the neoplasm, composed of uniform tumor cells, was arranged in solid nests or a trabecular pattern. The differential diagnosis included granulosa cell tumor. However, the strongly argyrophilic, chromogranin staining and ultrastructural presence of neurosecretory granules confirmed the diagnosis of primary ovarian carcinoid tumor. After a careful survey of the contralateral ovary and the gastrointestinal tract, the patient underwent a left oophorectomy. Her postoperative course was uneventful. The literature and the pathologic findings are reviewed and discussed, along with the differential diagnosis and treatment of primary ovarian carcinoid tumor.

Adenomatoid tumor of the female genital tract

OBJECTIVE

To remind gynecologists of the diagnosis of adenomatoid tumor of the female genital tract, a pathology which is often mistaken for leiomyoma, and in addition to warn of the malignant appearance of adenomatoid tumor.

MATERIALS AND METHODS

During the study period from January 1988 to May 1994, the clinical features and pathologic findings of 25 cases of adenomatoid tumor of the female genital tract were reviewed at the National Taiwan University Hospital.

RESULTS

The age of the patients ranged from 26 to 55 years with a median of 41 years. Adenomatoid tumor was an incidental finding during the surgical treatment of myoma (16 cases), cervical intraepithelial neoplasm (two cases), invasive cervical cancer (one case), adnexal cyst (five cases), and pregnancy with myoma (one case). Twenty-three cases had tumors in the uterine corpus and two in the fallopian tubes. Twenty percent of the patients had multiple tumors. Their sizes ranged from 1.0 to 8.0 cm. The case with the largest tumor measuring 8 cm in diameter is presented in detail. Its histologic, immunohistochemical and ultrastructural characteristics strongly support the mesothelial origin of adenomatoid tumor.

CONCLUSION

Some different results were obtained than those hitherto reported in the literature, such as younger age, frequency of multiple tumors, and fewer cases accompanied by leiomyomas.

Acute endothelial reperfusion injury after coronary artery bypass grafting

Coronary artery endothelium exhibits functional impairment after ischemia and reperfusion. Canine left anterior descending coronary arteries were exposed to ischemia (60 minutes) followed by reperfusion (60 minutes) through a left internal mammary artery graft. In organ chamber experiments, control (left circumflex coronary artery) and reperfused (left anterior descending coronary artery) arterial segments were contracted with prostaglandin F2 alpha and exposed to hypoxia (oxygen tension = 35 +/- 5 mm Hg). Reperfused coronary rings with endothelium exhibited contractions to hypoxia that were significantly greater than contractions in control rings with endothelium (+78% +/- 8% and +14% +/- 5%, respectively; p < 0.05). This phenomenon could be blocked by NG-monomethyl-L-arginine. Electron microscopic studies showed platelet adhesion and aggregation, denudation of the endothelium and disruption of the intercellular junctions, edematous subendothelial matrix, and vesiculation of the smooth muscle cells in reperfused LAD. Swelling, vacuole formation, and loss of neurofilament occurred in the nerve fibers accompanying the vessels. These phenomena were not observed in control vessels. This study demonstrates that early after coronary artery bypass grafting, hypoxia can induce coronary vasospasm mediated by an L-arginine-dependent metabolic pathway in the endothelium. The ultrastructural changes in the coronary endothelium include platelet adhesion, aggregation, and platelet-induced contraction of coronary smooth muscle. The endothelium-dependent hypoxic coronary vasospasm and ultrastructural changes in the coronary endothelium may play an important role in the pathogenesis of myocardial ischemia and infarction after coronary artery bypass grafting.

Termination of paroxysmal supraventricular tachycardia with a single oral dose of diltiazem and propranolol

The efficacy of a single oral dose combination of 120 mg diltiazem and 160 mg propranolol in terminating paroxysmal supraventricular tachycardia (PSVT) was evaluated in 15 patients. All 15 patients underwent electrical induction of PSVT that lasted longer than 15 min, and all underwent randomized crossover placebo and diltiazem and propranolol studies on 2 consecutive days. On each day PSVT was induced and placebo or diltiazem and propranolol was administered 15 min later. Electrical conversion of PSVT was performed when severe symptoms occurred or at the end of 240 min. With placebo PSVT lasted 164 +/- 89 (mean +/- SD) min; four patients had spontaneous conversion. With diltiazem and propranolol PSVT lasted 39 +/- 49 min (p less than .001); 14 patients had spontaneous conversion in an average of 27 +/- 15 min. None of the 14 patients had electrical reinduction of sustained PSVT after conversion. The sinus nodal recovery time during spontaneous or electrical conversion of PSVT was 911 +/- 459 msec with placebo and 1076 +/- 270 msec with diltiazem and propranolol (NS). Two patients developed transient second-degree atrioventricular block and junctional rhythm while on diltiazem and propranolol. Serum diltiazem and propranolol levels (ng/ml) after diltiazem and propranolol in five patients were, respectively, 49 +/- 26 and 108 +/- 101 at 15 min, 232 +/- 147 and 228 +/- 148 at 30 min, 254 +/- 169 and 370 +/- 393 at 45 min, 280 +/- 115 and 209 +/- 189 at 60 min, 188 +/- 72 and 268 +/- 264 at 120 min, and 118 +/- 57 and 265 +/- 148 at 240 min.(ABSTRACT TRUNCATED AT 250 WORDS)