Comparison between radiometry and spectrophotometry for the determination of angiotensin-converting enzyme activity in cerebrospinal fluid

Determination of angiotensin-converting enzyme (ACE) activity in cerebrospinal fluid (CSF) can help for establishing the diagnosis of neurosarcoidosis. We investigated the performance characteristics of two assays for ACE determination in 57 CSF, radiometry with [glycine-1-14C] benzoyl-L-histidyl-L-leucine and spectrophotometry with furylacryloyl-phenylalanyl-L-glycyl-L-glycine (FAPGG) as substrates. We compared both kinetic assays to an ELISA specific for human ACE. Within run and between run imprecisions were 14-17% for radiometry, 6-19% for spectrophotometry and 5-8% for ELISA. The limit of detection was 0.04 U/L for radiometry, 1.0 U/L for spectrophotometry and 0.156 μg/L for ELISA. The limit of quantification was 0.06 U/L for radiometry, 1.5 U/L for spectrophotometry, but not known for ELISA. The domain for quantification was 0.06-4.0 U/L for radiometry, 1.5-24 U/L for spectrophotometry and 0.156-10 μg/L for ELISA. Deming regression and Bland-Altman plots show good correlations between the three assays, but with high slopes, because both kinetic assays use different substrates and ELISA measures ACE molecule but not activity. Radiometry was more sensitive than spectrophotometry, which has a limit of detection above most pathological levels. ELISA could be an alternative to radiometry but only after complete evaluation, determination of normal values and assessment of its clinical value. We claim for standardization of ACE determination as well as in serum as in other biological fluids, in particular CSF.

Consistent localization of SARS-CoV-2 spike glycoprotein and ACE2 over TMPRSS2 predominance in placental villi of 15 COVID-19 positive maternal-fetal dyads

INTRODUCTION

While the COVID-19 pandemic continues to have a significant global health impact, rates of maternal to infant vertical transmission remain low (<5%). Parenchymal changes of placentas from COVID-19 infected mothers have been reported by several groups, but the localization and relative abundance of SARS-CoV-2 viral proteins and cellular entry machinery has not been fully characterized within larger placental tissue cohorts.

METHODS

An extended placental tissue cohort including samples from 15 COVID-19 positive maternal-fetal dyads (with n = 5 cases with evidence of fetal transmission) in comparison with 10 contemporary COVID-19 negative controls. Using comparative immunofluorescence, we examined the localization and relative tissue abundance of SARS-CoV2 spike glycoprotein (CoV2 SP) along with the co-localization of two SARS-CoV2 viral entry proteins angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2).

RESULTS/CONCLUSIONS

CoV2 SP was present within the villous placenta in COVID-19 positive pregnancies with and without evidence of fetal transmission. We further identified the predominance of ACE2 expression in comparison with TMPRSS2. Importantly, both CoV2 SP and ACE2 expression consistently localized primarily within the outer syncytiotrophoblast layer placental villi, a key physiologic interface between mother and fetus. Overall this study provides an important basis for the ongoing evaluation of SARS-CoV-2 physiology in pregnancy and highlights the importance of the placenta as a key source of primary human tissue for ongoing diagnostic and therapeutic research efforts to reduce the global burden of COVID-19.

Involvement of the digestive system in covid-19. A review

The SARS-CoV-2 pandemic is leading to high mortality and a global health crisis. The primary involvement is respiratory; however, the virus can also affect other organs, such as the gastrointestinal tract and liver. The most common symptoms are anorexia and diarrhea. In about half of the cases, viral RNA could be detected in the stool, which is another line of transmission and diagnosis. covid19 has a worse prognosis in patients with comorbidities, although there is not enough evidence in case of previous digestive diseases. Digestive endoscopies may give rise to aerosols, which make them techniques with a high risk of infection. Experts and scientific organizations worldwide have developed guidelines for preventive measures. The available evidence on gastrointestinal and hepatic involvement, the impact on patients with previous digestive diseases and operating guidelines for Endoscopy Units during the pandemic are reviewed.

Placental barrier against COVID-19

Vertical transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and possible induction of pregnancy complications, including miscarriage, fetal malformations, fetal growth restriction and/or stillbirth, are serious concerns for pregnant individuals with COVID-19. According to clinical information, the incidence of vertical transmission of SARS-CoV-2 is limited to date. However, even if a neonate tests negative for SARS-CoV-2, frequent abnormal findings, including fetal and maternal vascular malperfusion, have been reported in cases of COVID-19-positive mothers. Primary receptor of SARS-CoV-2 is estimated as angiotensin-converting enzyme 2 (ACE2). It is highly expressed in maternal-fetal interface cells, such as syncytiotrophoblasts, cytotrophoblasts, endothelial cells, and the vascular smooth muscle cells of primary and secondary villi. However other route of transplacental infection cannot be ruled out. Pathological examinations have demonstrated that syncytiotrophoblasts are often infected with SARS-CoV-2, but fetuses are not always infected. These findings suggest the presence of a placental barrier, even if it is not completely effective. As the frequency and molecular mechanisms of intrauterine vertical transmission of SARS-CoV-2 have not been determined to date, intensive clinical examinations by repeated ultrasound and fetal heart rate monitoring are strongly recommended for pregnant women infected with COVID-19. In addition, careful investigation of placental samples after delivery by both morphological and molecular methods is also strongly recommended.

ACE2 Expression in Pancreas May Cause Pancreatic Damage After SARS-CoV-2 Infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus that causes coronavirus disease 2019 (COVID-19) in human beings, has caused a serious public health issue.¹ Attention to pancreatic injury is lacking, which may impact patients' prognosis. In this study, we explored the expression and distribution of angiotensin-converting enzyme 2 (ACE2), the receptor of SARS-CoV-2, in the pancreas. Combined with clinical data, we showed that pancreatic injury can occur in some COVID-19 patients.

Genetic Association of Angiotensin-Converting Enzyme (ACE) Gene I/D Polymorphism with Preterm Birth in Korean Women: Case-Control Study and Meta-Analysis

Background and Objectives: The ACE gene encodes the angiotensin-converting enzyme (ACE), a component of the renin-angiotensin system. Increased ACE activity may cause abnormal regulation of placental circulation and angiogenesis, resulting in adverse pregnancy outcomes. Previous studies have reported that the insertion/deletion (I/D) polymorphism of the ACE gene is associated with the development of preterm birth (PTB). However, results of the association between ACE gene I/D and PTB are inconsistent in various populations. Therefore, we performed a case-control study and a meta-analysis to evaluate the association between ACE I/D polymorphism and PTB. Materials and Methods: We analyzed a total of 254 subjects (111 patients with PTB and 143 women at ≥38 weeks gestation) for the case-control study. For the meta-analysis, we searched Google Scholar, PubMed, and NCBI databases with the terms “ACE,” “angiotensin-converting enzyme,” “preterm birth,” “preterm delivery,” and their combinations. Results: Our results of the case-control study indicated that ACE I/D polymorphism is significantly associated with PTBs in the overdominant genetic model (odds ratio (OR) 0.57, 95% confidence interval (CI) 0.347–0.949, p = 0.029) and that the ID genotype of ACE I/D polymorphism has a protective effect for PTB (OR 0.57, 95% CI 0.333–0.986, p = 0.043). Similarly, the meta-analysis showed that the OR for the ACE gene ID genotype was 0.66 (95% CI 0.490–0.900, p < 0.01). Conclusion: The ACE gene ID genotype has a significant association with PTB and is a protective factor for PTB. A larger sample set and functional studies are required to further elucidate of our findings.

Changes in angiotensin II and angiotensin-converting enzyme of different tissues after prolonged hyperoxia exposure

Current study findings concerning changes in the renin-angiotensin system (RAS) in cases of hyperoxic acute lung injury (HALI) have shown conflicting results. This study aimed to detect the angiotensin II (Ang II) and angiotensin-converting enzyme (ACE) in a rat HALI model. Healthy male Sprague-Dawley rats were randomly assigned into three groups: the control group, HALI group and hyperbaric oxygen preconditioning (HBO₂-PC) group. HALI was induced by exposure to pure oxygen at 250 kPa for six hours. In the HBO₂-PC group, rats were exposed to oxygen at 250 kPa for 60 minutes twice daily for two consecutive days; HALI was induced at 24 hours after the last oxygen exposure.=After HALI, the lung, spleen and liver were harvested for HE staining and pathological examination. At one hour and 18 hours after HALI, the blood, liver, lung and spleen were collected for the detection of Ang II and ACE contents by enzyme-linked immunosorbent assay. Pathological examination showed the lung was significantly damaged and characteristics of HALI were observed, but there were no significant pathological changes in the liver and spleen. After HALI, Ang II and ACE contents of different tissues increased progressively over time, but the HBO₂-PC group showed reductions in the Ang II and ACE contents to a certain extent, especially at 18 hours after injury. These findings suggest prolonged hyperoxia exposure may activate the RAS, which may be associated with the pathogenesis of HALI. HBO₂-PC has a limited capability to inhibit RAS activation.

Cardiac ACE2/angiotensin 1-7/Mas receptor axis is activated in thyroid hormone-induced cardiac hypertrophy

OBJECTIVES

Thyroid hormone (TH) promotes marked effects on the cardiovascular system, including the development of cardiac hypertrophy. Some studies have demonstrated that the renin-angiotensin system (RAS) is a key mediator of the cardiac growth in response to elevated TH levels. Although some of the main RAS components are changed in cardiac tissue on hyperthyroid state, the potential modulation of the counter regulatory components of the RAS, such as angiotensin-converting enzyme type 2 (ACE2), angiotensin 1-7 (Ang 1-7) levels and Mas receptor induced by hyperthyroidism is unknown. The aim of this study was to investigate the effect of hyperthyroidism on cardiac Ang 1-7, ACE2 and Mas receptor levels.

METHODS

Hyperthyroidism was induced in Wistar rats by daily intraperitoneal injections of T4 for 14 days.

RESULTS

Although plasma Ang 1-7 levels were unchanged by hyperthyroidism, cardiac Ang 1-7 levels were increased in TH-induced cardiac hypertrophy. ACE2 enzymatic activity was significantly increased in hearts from hyperthyroid animals, which may be contributing to the higher Ang 1-7 levels observed in the T4 group. Furthermore, elevated cardiac levels of Ang 1-7 levels were accompanied by increased Mas receptor protein levels.

CONCLUSION

The counter-regulatory components of the RAS are activated in hyperthyroidism and may be contributing to modulate the cardiac hypertrophy in response to TH.

Sarcoidosis Presenting Addison's Disease

We herein describe a second Japanese case of sarcoidosis presenting Addison's disease. A 52-year-old man was diagnosed with sarcoidosis based on clinical and laboratory findings, including bilateral hilar lymphadenopathy and elevated levels of serum angiotensin-converting enzyme and lysozyme, as well as the presence of noncaseating epithelioid granulomas. The patient also exhibited general fatigue, pigmentation, weight loss, hypotension and hyponatremia, suggestive of chronic adrenocortical insufficiency. An endocrine examination confirmed primary adrenocortical insufficiency. This case suggests the direct involvement of sarcoid granuloma in the adrenal glands.

Laparoscopic fenestration of pancreatic serous cystadenoma: Minimally invasive approach for symptomatic benign disease

Serous cystadenoma (SC) is a benign pancreatic cystic tumor. Surgical resection is recommended for symptomatic forms, but laparoscopic fenestration of large symptomatic macrocystic SC was not yet described in the literature. In this study, 3 female patients underwent laparoscopic fenestration for macrocystic SC (12-14 cm). Diagnosis was established via magnetic resonance imaging and endoscopic ultrasound, with intra-cystic dosage of tumors markers (ACE and CA19-9) in 2 patients. All patients were symptomatic and operated on 15-60 mo after diagnosis. Radiological evaluation showed constant cyst growth. Patients were informed about this new surgical modality that can avoid pancreatic resection. The mean operative time was 103 min (70-150 min) with one conversion. The post-operative course was marked by a grade A pancreatic fistula in one patient and was uneventful in the other two. The hospital stay was 3, 10, and 18 d, respectively. The diagnosis of macrocystic SC was histologically-confirmed in all cases. At the last follow-up (13-26 mo), all patients were symptom-free, and radiological evaluation showed complete disappearance of the cyst. Laparoscopic fenestration, as opposed to resection, should be considered for large symptomatic macrocystic SC, thereby avoiding pancreatic resection morbidity and mortality.

New phenolic compounds from Coreopsis tinctoria Nutt. and their antioxidant and angiotensin i-converting enzyme inhibitory activities

Three new phenolic compounds, coretinphenol (1), coretincone (2), and coretinphencone (3), were isolated from the buds of Coreopsis tinctoria Nutt., together with nine known compounds, including butein (4), okanin (5), isoliquiritigenin (6), maritimetin (7), taxifolin (8), isookanin (9), marein (10), sachalinoside B (11), and 2-phenylethyl-β-d-glucoside (12). The chemical structures of these compounds were elucidated by extensive spectroscopic analysis and on the basis of their chemical reactivity. This work represents the first recorded example of the isolation of compounds 1–3, 6, 7, 9, 11, and 12 from C. tinctoria. Compounds 5–9 showed strong diphenyl(2,4,6-trinitrophenyl)iminoazanium (DPPH) radical-scavenging activity, with IC50 values of 3.35 ± 0.45, 9.6 ± 2.32, 4.12 ± 0.21, 6.2 ± 0.43, and 7.9 ± 0.53 μM, respectively. Compounds 2 and 8 exhibited angiotensin I-converting enzyme inhibitory activity, with IC50 values of 228 ± 4.47 and 145.67 ± 3.45 μM, respectively. The activities of phenolic compounds isolated from C. tinctoria support the medicinal use of this plant in the prevention of cardiovascular diseases.

Inhibition of reactive oxygen species in hypothalamic paraventricular nucleus attenuates the renin-angiotensin system and proinflammatory cytokines in hypertension

AIMS

To explore whether reactive oxygen species (ROS) scavenger (tempol) in the hypothalamic paraventricular nucleus (PVN) attenuates renin-angiotensin system (RAS) and proinflammatory cytokines (PICs), and decreases the blood pressure and sympathetic activity in angiotensin II (ANG II)-induced hypertension.

METHODS AND RESULTS

Male Sprague-Dawley rats were infused intravenously with ANG II (10 ng/kg per min) or normal saline (NS) for 4 weeks. These rats were treated with bilateral PVN infusion of oxygen free radical scavenger tempol (TEMP, 20 μg/h) or vehicle (artificial cerebrospinal fluid, aCSF) for 4 weeks. ANG II infusion resulted in increased mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA). These ANG II-infused rats also had higher levels of gp91(phox) (a subunit of NAD(P)H oxidase), angiotensin-converting enzyme (ACE), and interleukin-1 beta (IL-1β) in the PVN than the control animals. Treatment with PVN infusion of TEMP attenuated the overexpression of gp91(phox), ACE and IL-1β within the PVN, and decreased sympathetic activity and MAP in ANG II-infused rats.

CONCLUSION

These findings suggest that ANG II infusion induces elevated PICs and oxidative stress in the PVN, which contribute to the sympathoexcitation in hypertension. Inhibition of reactive oxygen species in hypothalamic paraventricular nucleus attenuates the renin-angiotensin system, proinflammatory cytokines and oxidative stress in ANG II-induced hypertension.

Measuring angiotensin-I converting enzyme inhibitory activity by micro plate assays: comparison using marine cryptides and tentative threshold determinations with captopril and losartan

To determine the angiotensin-I converting enzyme (ACE) inhibitory activity of marine cryptides, different methods were tested. ACE inhibition was measured using two synthetic substrates, (N-[3-(2-furyl) acryloyl]-Phe-Gly-Gly (FAPGG) and N-hippuryl-His-Leu hydrate salt (HHL)), and a natural one, angiotensin-I. The IC50 value (defined as the concentration of inhibitory molecule needed to inhibit 50% of the ACE activity) of the reference synthetic inhibitor captopril was in the nanomolar range (1.79-15.1 nM) when synthetic substrates were used, whereas it exhibited IC50 of micromolar range (16.71 μM) with angiotensin-I. We chose losartan, an antagonist of angiotensin-II receptor as negative control for the ACE inhibition. Losartan was also able to inhibit ACE whatever the substrate tested, with IC50 of micromolar range (17.13-146 μM). We defined this value as a limit above which molecules are not showing in vitro ACE inhibitory activity. Val-Trp (VW), Val-Tyr (VY), Lys-Tyr (KY), Lys-Trp (KW), Ile-Tyr (IY), Ala-Pro (AP), Val-Ile-Tyr (VIY), Leu-Lys-Pro (LKP), Gly-Pro-Leu (GPL), Ala-Lys-Lys (AKK), and Val-Ala-Pro (VAP) were tested as inhibitors of ACE with synthetic and natural substrates. IC50 displayed were substrate-dependent. With FAPGG as substrate, IW, VAP, KY, IY, AP, AKK, and VIY show IC50 values over the IC50 value of losartan and should not be considered as inhibitors of ACE. VY, VW, KW, and LKP exhibited IC50 value lower than the IC50 value of losartan for all substrates tested and were thus considered as good candidates for effectively decreasing hypertension. It appears that the comparison of IC50 is not consistent when IC50 values are obtained with different substrates and different methods. In vitro ACE inhibitory activity assays should always include various ACE substrates and references such as captopril and a negative control to obtain data reliable to discriminate ACE inhibitory peptides.

Childhood sarcoidosis: diagnostic issues

Childhood sarcoidosis is a rare granulomatous disorder that affects several systems including the lungs, skin, eyes, and bones. On histopathology, non-caseating granuloma is the classic feature. We present a case of late childhood sarcoidosis of the skin, lungs, and bones demonstrating granulomas with fibrinoid necrosis, making distinction from tuberculosis difficult.

Utero-placental expression of angiotensin-(1-7) and ACE2 in the pregnant guinea-pig

BACKGROUND

In humans, trophoblast invasion, vascular remodeling and placental development are critical to determine the fate of pregnancy. Since guinea-pigs (GP) and humans share common pregnancy features including extensive trophoblast invasion, transformation of the uterine spiral arteries and a haemomonochorial placenta, the GP animal model was deemed suitable to extend our knowledge on the spatio-temporal immunoreactive expression of the vasodilator arpeptide of the renin-angiotensin system, angiotensin-(1-7) [Ang-(1-7)] and its main generating enzyme, angiotensin converting enzyme 2 (ACE2).

METHODS

Utero-placental units were collected in days 15, 20, 40 and 60 of a 64-67 day long pregnancy in 25 Pirbright GP. Ang-(1-7) and ACE2 expression in utero-placental units were evaluated by immunohistochemistry.

RESULTS

Ang-(1-7) and ACE2 were detected in the endothelium and syncytiotrophoblast of the labyrinthine placenta, interlobium, subplacenta, giant cells, syncytial sprouts, syncytial streamers, and myometrium throughout pregnancy. In late pregnancy, perivascular or intramural trophoblasts in spiral and mesometrial arteries expressed both factors. Immunoreactive Ang-(1-7) and ACE2 were present in decidua and in the vascular smooth muscle of spiral, myometrial and mesometrial arteries, which also express kallikrein (Kal), the bradykinin receptor 2 (B2R), vascular endothelial growth factor (VEGF) and its type 2 receptor (KDR), but no endothelial nitric oxide synthase (eNOS). In addition, the signal of Ang-(1-7) and ACE2 was especially remarkable in giant cells, which also show Kal, B2R. eNOS, VEGF and KDR.

CONCLUSIONS

The spatio-temporal expression of Ang-(1-7) and ACE2 in GP, similar to that of humans, supports a relevant evolutionary conserved function of Ang-(1-7) and ACE2 in decidualization, trophoblast invasion, vascular remodeling and placental flow regulation, as well as the validity of the GP model to understand the local adaptations of pregnancy. It also integrates Ang-(1-7) to the utero-placental vasodilatory network. However, its antiangiogenic effect may counterbalance the proangiogenic activity of some of the other vasodilator components.

Contribution of T cell subset analysis in induced sputum in diagnosing ocular sarcoidosis

OBJECTIVE

The aim of this study was to establish a correlation between the diagnosis of ocular sarcoidosis and the presence of an elevated CD4/CD8 ratio in the induced sputum(IS) of patients with uveitis and no other systemic symptoms.

METHODS

This retrospective chart review study included all newly diagnosed uveitis patients treated between 1998-2006. IS examinations and determination of angiotensin-converting enzyme (ACE) levels were carried out. A CD4/CD8 ratio > 2.5 and an ACE level > 145 Cd/ml/min were considered abnormal. The etiology of uveitis was retrieved from the medical records.

RESULTS

Twenty males and 26 females (mean age 47 +/- 16.1 years) were enrolled. The CD4/CD8 ratio was elevated in 26 (56.5%) patients, and five (10.9%) were diagnosed as having sarcoidosis by the end of follow-up. The sensitivity and specificity of the T lymphocytes CD4/CD8 ratio in diagnosing sarcoidosis were 100% and 48.8%, respectively. CD4/CD8 ratios were not significantly different between the sarcoid and non-sarcoid groups (p > 0.05), but the former tended to have higher levels (p = 0.0991). The mean ACE level of the sarcoid patients was significantly higher than that of the non-sarcoid patients (p < 0.001).

CONCLUSION

CD4/CD8 lymphocytes ratios obtained by IS were sensitive in uveitis patients with concomitant sarcoidosis, suggesting that analysis of T cells subsets in IS may rule out an etiology of sarcoidosis in newly diagnosed uveitis patients.

Angiotensin-converting enzyme gene variant and its levels: risk factors for myocardial infarction in a South Indian population

INTRODUCTION

Recently, there has been increasing evidence that genetic variation in the angiotensin-converting enzyme (ACE) plays an important role in myocardial infarction. Therefore, the present study was carried out with the aim of investigating the association of the ACE gene insertion/deletion (I /D) polymorphism and its levels in myocardial infarction patients and their first-degree relatives (FDRs).

METHODS

206 patients with myocardial infarction, 168 FDRs and 210 control subjects were enrolled in the study. ACE I /D polymorphism was determined using the polymerase chain reaction method. Serum ACE levels were measured using the photometric method.

RESULTS

The DD genotype and ACE activity were significantly higher in patients (p-value is 0.00006 and 0.0001, respectively) and FDRs (p-value is 0.003 and 0.04, respectively) compared with the controls.

CONCLUSION

ACE DD genotype and ACE levels are important risk factors for myocardial infarction. This study indicates that the higher frequency of the DD genotype and ACE levels observed in FDRs may increase susceptibility to developing myocardial infarction.

Novel angiotensin-converting enzyme (ACE) inhibitory peptides derived from boneless chicken leg meat

Four peptides that inhibit angiotensin-converting enzyme (ACE) were separated from the hydorlysate of boneless chicken leg meat digested with artificial gastric juice (pepsin). Two peptides were identified as the peptides encrypted in myosin heavy chain. The peptide P1 (MNVKHWPWMK) corresponds to the amino acid sequence from amino acids 825 to 834 of myosin heavy chain, and the peptide P4 (VTVNPYKWLP) corresponds to the amino acid sequence from amino acids 125 to 135 of myosin heavy chain. They are novel ACE inhibitory peptides derived from chicken, and IC(50) values of P1 and P4 were determined as 228 and 5.5 microM, respectively. Although these values were much larger than 0.022 microM for captopril, a typical synthetic ACE inhibitor, they are comparable to IC(50) values reported for various ACE inhibitory peptides derived from foods. Because the peptide P4 has a relatively low IC(50) value, it is a good starting substance for designing food supplements for hypertensive patients.

Study of Serum and Tissues Angiotensin Converting Enzyme (ACE) Activity in Rat with Gentamicin Induced Renal Toxicity

PURPOSE

In this research ACE activity (as a marker of epithelial injury) was studied in rats with gentamicin induced renal toxicity.

METHODS

Male Sprague-Dawley rats were sacrificed 1, 3, 5, and 7 days after gentamicin injection, 100 mg/kg/day for 1, 3, 5, and 7 consecutive days. ACE activity was measured in serum, kidney and lung. These data were compared with normal saline-treated rats. Histological scoring of renal cortical pathology was performed on days 1, 3, 5, and 7.

RESULTS

Treatment of rats with gentamicin resulted in renal damage evidenced by proteinuria, polyuria, and decreased creatinine clearance. The damage to the kidney proximal tubule was evident by (a) the histological analysis at light microscopy and (b) the augmentation in the urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG). Kidney ACE activity decreased while lung and serum ACE activity didn't change until day 7. Lung ACE activity increased significantly on day 7. Kidney and serum ACE activity increased too. Blood pressure increased significantly on day 7. This corresponded well with the lung ACE activity increment.

CONCLUSION

These data suggest that kidney ACE activity decreased significantly just one day after gentamicin administration and prior to kidney NAG decrease.

Angiotensin-converting enzyme in sarcoidosis

Using a spectrophotometric assay with L-hippuryl-L-histidyl-L-leucine as substrate, s-angiotensin-converting enzyme (SACE) was determined in 85 sarcoidosis patients, 116 healthy controls and 150 patients with various non-sarcoid diseases. The controls showed no sex or age variation and had SACE levels of 24.4 +/- 6.2 U/ml (mean +/- 1 S.D.), giving a normal range (mean +/- 2 S.D.) of 12.0-36.8 U/ml. In contrast, the sarcoidosis patients had SACE values of 38.4 +/- 14.4 U/ml, with the highest values in cases with active sarcoidosis and duration of disease longer than two years (49.0 +/- 12.7 U/ml). A total of 41% of the sarcoidosis patients had elevated SACE, in the chronic active group 85%. Patients with renal failure, Hodgkin's disease and other malignant lymphoma had low SACE, whereas patients with lung cancer and tuberculosis had normal SACE values. Among 266 patients with non-sarcoid diseases and healthy controls, only two had slightly elevated SACE, but so far we have not found SACE above 40 U/ml in other than sarcoidosis patients. An elevated SACE is rather specific in sarcoidosis and seems to be a useful supplement to existing diagnostic measures.

Free light chains of immunoglobulins in serum from patients with rheumatoid arthritis, sarcoidosis, chronic infections and pulmonary cancer

Free light chains of immunoglobulins were measured in serum from 181 patients with rheumatoid arthritis (RA), sarcoidosis, pulmonary tuberculosis, pulmonary cancer and chronic bronchitis, i.e. patients with long-term stimulation of the immune system. Increased concentrations of light chains were found in patients with active sarcoidosis, and the light chain level appeared to be a marker of disease activity in sarcoidosis. The mean (+/- S.D.) concentration of kappa plus lambda chains in active sarcoidosis of more than two years' duration was 38.3 +/- 13.7 mg/l, that is twice the concentration of 19.4 +/- 5.5 mg/l found in normals. Some patients with seropositive RA also had increased serum values. The light chain concentrations in seropositive RA were correlated to the severity of the disease measured by clinical staging and laboratory tests. A modest increase in light chains was observed in one patient with tuberculosis, and in two patients each with chronic bronchitis and pulmonary cancer.

Isoflavone content and its potential contribution to the antihypertensive activity in soybean Angiotensin I converting enzyme inhibitory peptides

A soybean angiotensin I converting enzyme (ACE) inhibitory peptide fraction was reported to have antihypertensive activity in a rat study. The purpose of the present study was to examine if the presence of isoflavones in the soybean ACE inhibitory peptide fraction may contribute to the blood-pressure-lowering property. The isoflavone concentration in soybean samples was analyzed on a C 18 reverse-phase column using a two-step gradient solvent system. Producing soybean hydrolysate led to a nearly 40% loss of isoflavones compared with the original soybean flour, but the isoflavone composition did not change and the dominant isoflavone chemicals remained as 6''-O-malonylgenistin and 6''-O-malonyldaidzin. Ion exchange chromatography affected significantly both the content and the composition of the isoflavones. The dominant isoflavones in the ion-exchanged fraction were aglycones and nonacylated isoflavones, accounting for 95.8% of the total amount of 987.7 microg/g. It was calculated that the isoflavone content in the soybean ACE inhibitory peptide fraction was 25 times less than the minimal effective isoflavone dose reported. In vitro study also showed that adding isoflavones into both soybean flour hydrolysate and soybean ACE inhibitory peptide samples to a concentration of as high as 31.5% (w/w) did not affect ACE inhibitory activity (IC 50 values). The findings along with previously published results indicated that the contribution of isoflavones in soybean ACE inhibitory peptide fraction to the blood-pressure-lowering property in a short-term feeding study might be negligible.

Comparative expression analysis of the renin-angiotensin system components between white and brown perivascular adipose tissue

Recent studies have demonstrated that the rat adipose tissue expresses some of the components necessary for the production of angiotensin II (Ang II) and the receptors mediating its actions. The aim of this work is to characterize the expression of the renin-angiotensin system (RAS) components in perivascular adipose tissue and to assess differences in the expression pattern depending on the vascular bed and type of adipose tissue. We analyzed Ang I and Ang II levels as well as mRNA levels of RAS components by a quantitative RT-PCR method in periaortic (PAT) and mesenteric adipose tissue (MAT) of 3-month-old male Wistar-Kyoto rats. PAT was identified as brown adipose tissue expressing uncoupling protein-1 (UCP-1). It had smaller adipocytes than those from MAT, which was identified as white adipose tissue. All RAS components, except renin, were detected in both PAT and MAT. Levels of expression of angiotensinogen, Ang-converting enzyme (ACE), and ACE2 were similar between PAT and MAT. Renin receptor expression was five times higher, whereas expression of chymase, AT(1a), and AT(2) receptors were significantly lower in PAT compared with MAT respectively. In addition, three isoforms of the AT(1a) receptor were found in perivascular adipose tissue. The AT(1b) receptor was found at very a low expression level. Ang II levels were higher in MAT with no differences between tissues in Ang I. The results show that the RAS is differentially expressed in white and brown perivascular adipose tissues implicating a different role for the system depending on the vascular bed and the type of adipose tissue.

Diverse clinical presentations of orbital sarcoid

PURPOSE

To review the clinical presentation, location, systemic features, management, and natural history of orbital sarcoid.

DESIGN

Retrospective, noncomparative, interventional case series.

METHODS

Twenty patients with sarcoid and sarcoidal reactions of the orbit underwent biopsy, excision of localized mass, and systemic and local treatment at a tertiary referral center. Age, gender, onset, symptoms and signs, characterization of disease process, location, systemic disease, associated systemic features, management, and recurrence of the disease were identified.

RESULTS

Of the 20 patients studied, five were male and 15 were female. The mean age was 50.55 +/- 16.43 years (range, 18 to 77 years). The most common symptom was the presence of a palpable mass, followed by eyelid swelling. Review of the computed tomographic scans revealed four main categories of presentation: lacrimal gland infiltration (n = 11; 55%), orbital mass (n = 4; 20%), optic nerve sheath and dural involvement (n = 4; 20%), and extraocular muscle involvement (n = 1; 5%). Concurrent systemic sarcoidosis discovered after the diagnosis of orbital sarcoid was present in 10 cases (50%). The remaining showed no evidence of systemic disease at follow-up. Angiotensin converting enzyme analysis was performed in 10 cases; in only two (20%) was elevated, and in the remaining eight, it was within normal levels.

CONCLUSIONS

Orbital sarcoid has a diverse clinical presentation varying from lacrimal gland infiltration, soft tissue orbital mass, intraorbital and extraorbital optic nerve sheath and dural involvement, to extraocular muscle involvement. The orbital site most commonly involved was the lacrimal gland.