Diencephalic Syndrome: Misleading Clinical Onset of Low-Grade Glioma

BACKGROUND

Diencephalic Syndrome is an atypical early manifestation of low-grade gliomas; so, it is important to detect it in patients that experience a failure to thrive despite adequate length growth and food intake. The purpose of this article is to focus attention on this rare but potentially dangerous cause of poor weight gain or stunting in childhood.

MATERIALS AND METHODS

We describe four patients with Diencephalic Syndrome and low-grade gliomas who were evaluated in our institution from January 2017 to December 2021.

CASE DESCRIPTION AND RESULTS

two patients presented with suspected malabsorption, and two presented with a suspected eating disorder. In all cases, neurological symptoms appeared late, explaining the reason for the diagnostic delay, which impacts negatively on prognosis and on quality of life. Currently, patients 1 and 2 have stable disease in second-line therapy, patient 3 has stable disease post end of second-line therapy, and patient 4 has stable disease in first-line therapy. Everyone is in psychophysical rehabilitation.

CONCLUSIONS

A multidisciplinary evaluation is essential in order to make an early diagnosis and improve prognosis and quality of life.

Report of Two Cases of Pediatric IgG4-Related Lymphadenopathy (IgG4-LAD): IgG4-Related Disease (IgG4-RD) or a Distinct Clinical Pathological Entity?

IgG4-related disease (IgG4-RD) is a recently discovered immune-mediated fibroinflammatory condition, uncommon in the pediatric population, that could involve multiple organs and induce cancer-like lesions and organ damage. Its main features are multiple injuries in different sites, a dense lymphoplasmacytic infiltrate rich in IgG4 plasma cells, storiform fibrosis, and often high serological concentrations of IgG4. Autoimmune pancreatitis is the most common manifestation, mainly in adults. Two cases of IgG4-RD in children with lymph node localization of disease are reported. Localized or systemic lymph node involvement is common, but lymph node enlargement as the first and only manifestation of IgG4-RD is unusual, and therefore, hard to differentiate from other diseases. IgG4-related lymphadenopathy (IgG4-LAD) is most likely a distinct disease, described as isolated lymphadenopathy, related to the presence of elevated numbers of IgG4-positive plasma cells. Both disorders are likely to be misdiagnosed in children because they are characterized by rare and polymorphic features. IgG4-RD and IgG4-LAD should be considered in the differential diagnosis of disorders characterized by lymphadenopathy of uncertain etiology.

Neuroblastic tumors and neurofibromatosis type 1: A retrospective multicenter study in Italy and systematic review of the literature

BACKGROUND

Neuroblastic tumors (NBTs) are the most common extra-cranial solid tumors of childhood. Neurofibromatosis type 1 (NF1) is the most common neurocutaneous disorder with a predisposition to tumors. The co-occurrence of NBTs in the setting of NF1 has been occasionally reported, suggesting a non-casual association and likely configuring a spectrum of neural crest-derived disorders.

AIM OF THE STUDY

To explore the occurrence of NBTs within NF1 and to report on its natural history, therapeutic strategies, and outcomes in an Italian cohort of children with NF1 and in the literature.

SUBJECTS AND METHODS

Study (a): a retrospective analysis of questionnaire-based data [years 1979-2017] derived from the databases of the Italian Registry for Neuroblastoma (RINB) of the Italian Society of Pediatric Onco-Haematology (AIEOP); and Study (b): a systematic review search on NF1/NB co-occurrence.

RESULTS

Study (a) identified eight children with NBTs, 0.2% of patients registered in the RINB, fulfilling the diagnostic criteria for NF1. The primary site of NBTs was abdominal in six patients. The NBTs were neuroblastoma (NB) in five patients, ganglioneuroblastoma (GNB) in one, patient, and ganglioneuroma (GN) in two. Metastatic diffusion occurred in three out of eight children. MYCN gene testing, performed in the tumors of five patients, resulted not-amplified. The major features of NF1 included the following: NF1 family history in four patients, café-au-lait spots in all, freckling in six, Lisch nodules in three, and neurofibromas in three. With regard to the outcome, four children survived three of these for the progression of NB and one for a second tumor. Study (b) identified 12 patients with NF1/NB from the years 1966-2017, and the median age at diagnosis was 27 months (range = 0-168 months). The primary site of NB was thoracic. The prevalent histotype was NB in nine patients, GNB in two, and GN in one. Eight/nine NBs were metastatic. The MYCN gene was amplified in the only studied case. The NF1 features included NF1 family history in seven patients; the major NF1 features were café-au-lait spots in nine patients, freckling in one, Lisch nodules in none, and neurofibromas in six. The outcome was good for only two children, while eight children died of neuroblastoma, at a median age of 49.5 months (range = 2.4-174 months), with a median survival time of 21.75 months after diagnosis.

CONCLUSIONS

To our knowledge, this represents the first systematic study on the occurrence of NBTs in NF1. This confirms that NBs are rare per se in the setting of NF1 (0.2% of all NBs) and even if compared to the overall frequency of malignancies in NF1 (i.e., 14.7%). The male:female ratio in study (a) (0.6) was different from what was recorded in study (b) (1.5) and in line with the overall increased frequency of malignancies in females with NF1. The median ages at diagnosis of NB in either study (a) or (b) were concordant with what occurred in the NB population. In study (a) versus study (b), the frequency of metastatic diffusion was lower, likely indicating less awareness on work-ups for malignancies in old NF1 series in the literature. The outcome was much better in study (a) than in study (b), indicating that multidisciplinary treatment for NB is highly recommended.

PCDH19-Related Epilepsies

Protocadherin-19 (PCDH19) is considered one of the most relevant genes related to epilepsy. To date, more than 150 mutations have been identified as causative for PCDH19-female epilepsy (also known as early infantile epileptic encephalopathy-9, EIEE9), which is characterized by early onset epilepsy, intellectual disabilities, and behavioral disturbances. More recently, mosaic-males (i.e., exhibiting the variants in less than 25% of their cells) have been described as affected by infant-onset epilepsy associated with intellectual disability, as well as compulsive or aggressive behavior and autistic features. Although little is known about the physiological role of PCDH19 protein and the pathogenic mechanisms that lead to EIEE9, many reports and clinical observation seem to suggest a relevant role of this protein in the development of cellular hyperexcitability. However, a genotype–phenotype correlation is difficult to establish. The main feature of EIEE9 consists in early onset of seizures, which generally occur in clusters lasting 1 to 5 minutes and repeating up to 10 times a day for several days. Seizures tend to present during febrile episodes, similarly to the first phases of Dravet syndrome and PCDH19 variants have been found in ∼25% of females who present with features of Dravet syndrome and testing negative for SCN1A variants. There is no “standardized” treatment for PCDH19-related epilepsy and most of the patients receiving a combination of several drugs. In this review, we focus on the latest researches on these aspects, with regard to protein expression, its known functions, and the mechanisms by which the protein acts. The clinical phenotypes related to PCDH19 mutations are also discussed.

Gamma-Aminobutyric Acid Type A Receptor Genes and Their Related Epilepsies

Gamma-aminobutyric acid type A (GABA-A) receptor subunit gene mutations, which include GABRA1, GABRB3, GABRD, and GABRG2, are often involved in several genetic epilepsy syndromes and other neuropsychiatric diseases like autism spectrum disorder, schizophrenia, and anxiety. GABA-A are ligand-gated ionic channels, and are involved firstly in the fast inhibitory synaptic transmission of the central nervous system. The GABA receptors include the ionotropic GABA-A and GABA-C receptors and the metabotropic GABA-B receptors. According to the site in which mutations occur, they cause disorders in channel opening, “lock-and-pull” receptor system functioning, and capable of causing a specific epilepsy phenotype. The aim of this article is to summarize the most recent literature findings, considering genetic mutations, clinical features, genotype/phenotype correlation, and therapy about neurodevelopment diseases correlated to GABA receptors dysfunction, in particular epilepsy. According to our findings, we conclude that further mutation analysis could permit genotype–phenotype correlation and give more information about the best efficient treatment, even if—at present—more clinical and genetic studies are necessary.

Continuous Estimation of CO2 Production during Exercise

A new method was developed for continuous isotopic estimation of human whole body CO2 rate of appearance (Ra) during non-steady state exercise. The technique consisted of a breath-by-breath measurement of 13CO2 enrichment (E) and a real-time fuzzy logic feedback system which controlled NaH13CO3 infusion rate to achieve an isotopic steady state. Ra was estimated from the isotope infusion rate and body 13CO2 enrichment which was equal to E at the isotopic steady state. During a non-steady state incremental cycle exercise (5 w/min or 10 w/min), NaH13CO3 infusion rate was successfully increased by the action of feedback controller so as to keep E constant.

Gastric restitution is inhibited by dexamethasone, which is reversed by hepatocyte growth factor and rebamipide

BACKGROUND

Glucocorticoids have been shown to induce peptic ulcers, especially when co-administered with NSAIDs. Hepatocyte growth factor (HGF) plays a role in gastric ulcer repair, facilitating the restitution of gastric mucosal epithelial cells. HGF expression is induced by PGs in gastric fibroblasts. We hypothesized that dexamethasone (DEX) may inhibit PG production and HGF expression, thus inhibiting HGF-induced gastric epithelial restitution.

AIM

To investigate the effect of DEX on gastric restitution, using cultured gastric cells, the role of HGF in the restitution inhibited by DEX, and the effect of rebamipide on DEX- inhibited restitution.

METHODS

Human gastric fibroblasts were prepared from human stomach obtained at surgery; PGE2 and HGF is determined by ELISA; Restitution was assessed by the round wound restitution model, using coculture of gastric fibroblasts and epithelial cells; COX-2 and HGF mRNA were quantified by TaqMan RT-PCR system.

RESULTS

1. DEX inhibited HGF mRNA and COX-2 mRNA. Accordingly, it inhibited PGE2 and HGF release. 2. DEX inhibited the restitution of gastric cells. 3. The inhibition of restitution was reversed by HGF and rebamipide to the same extent. 4. Rebamipide induced PGE2 and HGF.

CONCLUSION

DEX inhibits restitution via HGF depletion, and rebamipide reverses the inhibited restitution by HGF induction.

Effects of 12 months of exercise training on salivary secretory IgA levels in elderly subjects

BACKGROUND

The immune system declines in efficiency with advancing age, making the elderly less resistant to pathogenic microorganisms. Upper respiratory tract infection (URTI) is a common illness. Recent studies have shown that suppression of secretory immunoglobulin A (SIgA) is associated with increased incidence of URTI.

OBJECTIVE

To assess the effect of exercise on salivary SIgA in elderly subjects.

METHODS

Forty five elderly subjects (18 men, 27 women; mean (SD) age 64.9 (8.4) years) performed both 60 minute resistance and 60 minute moderate endurance training a week for 12 months. Saliva samples were obtained before training, and at four and 12 months during the training period. Salivary SIgA concentrations were measured by enzyme linked immunosorbent assay, and the SIgA secretion rate was calculated.

RESULTS

SIgA concentrations before training, and at four and 12 months during training were 24.7 (14.4), 27.2 (14.2), and 33.8 (18.5) micro g/ml respectively. SIgA secretion rates were 29.5 (26.0), 33.8 (27.2) and 46.5 (35.1) micro g/min respectively. The results indicate that both the concentration and secretion rate of SIgA significantly (p<0.01) increased during 12 months of exercise in these elderly subjects.

CONCLUSION

Regular moderate exercise seems to enhance mucosal immune function in elderly subjects.

Relationship between mitochondrial DNA polymorphism and the individual differences in aerobic performance

This study focused on the mitochondrial DNA (mtDNA) as the genetic factor most likely to bring about the individual difference in endurance capacity or its trainability. Platelets contain mtDNA but no nuclear DNA, whereas rho(0)-HeLa cells have nuclear DNA but no mtDNA. The oxidative capacity of mitochondria in the cultured cells, which were fused rho(0)-HeLa cell with platelets obtained from individual subjects (the so-called "cybrids"), reflects the individual mtDNA polymorphism in the gene-coding region. The purpose of this study was to investigate the relationship between the oxidative capacity of cybrids and the individual difference in endurance capacity, or its trainability. Forty-one sedentary young males took part in an 8-week endurance training program. They were determined by using their VO(2 max) as an index of endurance capacity on an ergocycle before and after the endurance training program. The relations between VO(2 max) before endurance training or the change of it by endurance training and the oxidative capacity of cybrids were investigated. There was no relation between them, and two groups were drawn from all subjects, based on one standard division of their initial VO(2 max): the higher pre-VO(2 max) group (n = 6) and the lower pre-VO(2 max) group (n = 5) (51.8 +/- 3.5 ml/min/kg vs. 33.3 +/- 3.8 ml/min/kg, p < 0.01). No significant difference was found between the O(2) consumption of the cybrids in the higher initial VO(2 max) group and that in the lower initial VO(2 max) group (16.3 +/- 4.9 vs. 15.9 +/- 2.0 nmol O(2)/min/10(7) cells, NS). Furthermore, neither the cytochrome c oxidase (COX) activity nor the complex I + III activity of cybrids showed a significant difference between the two groups. The oxidative capacity of cybrids between the high trainability group (n = 6) (Delta VO(2 max) 12.1 +/- 1.6 ml/min/kg) and the low trainability group (n = 9) (Delta VO(2 max) 2.3 +/- 0.5 ml/min/kg) was also similar. Thus the mtDNA polymorphism is very unlikely to relate to the individual difference in endurance capacity or its trainability in young sedentary healthy subjects.

The effects of cytoplasmic transfer of mtDNA in relation to whole-body endurance performance

The purpose of this study was to examine the relation between whole-body aerobic capacity and mitochondrial facilities. The mitochondrial enzyme system of oxidative phosphorylation (OXPHOS) is encoded both by mitochondrial DNA (mtDNA) and nuclear DNA. To identify the effect of mtDNA on whole-body aerobic capacity, we fused the platelets of the study subjects that contained mtDNA but that lacked nuclear DNA with rho(0) HeLa cells, which lacked mtDNA, and isolated repopulated cybrids. The mitochondrial respiratory functions of the cybrids, estimated from cell oxygen consumption and cytochrome-c oxidase (CCOX), were compared between endurance athletes and sedentary controls. The oxygen consumption was 18.5 +/- 3.9 and 18.2 +/- 4.1 nmol/min/ml/10(7) cells in athletes and controls, respectively. The CCOX activity was 98.8 +/- 17.5 and 116.7 +/- 9.8%, compared with fibroblasts in athletes and controls, respectively. No significant difference was noted between groups in either cell oxygen consumption or CCOX activity. These results show that the OXPHOS enzymes coded by mtDNA do not strongly influence whole-body aerobic fitness.

[Frequent convulsions in the post-eruptive stage of exanthem subitum]

We report here three infants with frequent convulsions in the post-eruptive stage of exanthem subitum (ES) due to human herpesvirus 6 (HHV-6) infection. Postictal electroencephalogram (EEG) showed in all the patients abnormal epileptic discharges, which disappeared in the following by three to eighteen months. In one case, brain magnetic resonance imaging (MRI) revealed focal gliosis. SPECT demonstrated hypoperfusion of the lesion. In the cerebro spinal fluid (CSF) of all the patients, HHV-6 DNA was negative on polymerase chain reaction (PCR) and HHV-6 antibodies were not significantly increased. Although encephalitis has been reported to complicate primary HHV-6 infection, our patients were not diagnosed as having encephalitis because of the clinical, CSF, EEG and CT findings. However, they had frequent convulsions. Not only virus invasion but also a secondary reaction including vasculitis may cause the central nervous system complications of HHV-6 infection. Frequent convulsions may occur in the post-eruptic stage after HHV-6 infection.

Functional integrity of mitochondrial genomes in human platelets and autopsied brain tissues from elderly patients with Alzheimer's disease

To determine whether pathogenic mutations in mtDNA are involved in phenotypic expression of Alzheimer's disease (AD), the transfer of mtDNA from elderly patients with AD into mtDNA-less (rho0) HeLa cells was carried out by fusion of platelets or synaptosomal fractions of autopsied brain tissues with rho0 HeLa cells. The results showed that mtDNA in postmortem brain tissue survives for a long time without degradation and could be rescued in rho0 HeLa cells. Next, the cybrid clones repopulated with exogenously imported mtDNA from patients with AD were used for examination of respiratory enzyme activity and transfer of mtDNA with the pathogenic mutations that induce mitochondrial dysfunction. The presence of the mutated mtDNA was restricted to brain tissues and their cybrid clones that formed with synaptosomes as mtDNA donors, whereas no cybrid clones that isolated with platelets as mtDNA donors had detectable mutated mtDNA. However, biochemical analyses showed that all cybrid clones with mtDNA imported from platelets or brain tissues of patients with AD restored mitochondrial respiration activity to almost the same levels as those of cybrid clones with mtDNA from age-matched normal controls, suggesting functional integrity of mtDNA in both platelets and brain tissues of elderly patients with AD. These observations warrant the reassessment of the conventional concept that the accumulation of pathogenic mutations in mtDNA throughout the aging process is responsible for the decrease of mitochondrial respiration capacity with age and with the development of age-associated neurodegenerative diseases.

Continuous estimation of CO2 production during exercise

A new method was developed for continuous isotopic estimation of human whole body CO2 rate of appearance (Ra) during non-steady state exercise. The technique consisted of a breath-by-breath measurement of 13CO2 enrichment (E) and a real-time fuzzy logic feedback system which controlled NaH13CO3 infusion rate to achieve an isotopic steady state. Ra was estimated from the isotope infusion rate and body 13CO2 enrichment which was equal to E at the isotopic steady state. During a non-steady state incremental cycle exercise (5 w/min or 10 w/min), NaH13CO3 infusion rate was successfully increased by the action of feedback controller so as to keep E constant.

[The alteration of PyNPase activity in breast cancers due to preoperative oral administration of 5'-DFUR]

To estimate the alteration of pyrimidine nucleoside phosphorylase (PyNPase) activity by 5'-DFUR, we determined its activity in the breast tissue of two patient groups. Group A (21 patients) were given 5'-DFUR (mean 9,000 mg) preoperatively, and group B (21 patients) were given no anticancer agents. There were no significant differences between the groups in background factors such as age, clinical stage and pathological features. Comparison of PyNPase activity in both groups among specimens of carcinoma, normal breast glands and lymph nodes revealed that the activity in carcinomas and lymph nodes was significantly higher than in normal breast glands. Comparison of group A with group B showed that group A had lower activity in carcinomas and lymph nodes than in group B, although the difference was not significant. An inter-group comparison of carcinomas was made in detail by subgrouping according to age and pathological features. In group B, PyNPase activity in older patients (> or = 50 y.o) was significantly higher than in younger patients (< 50 y.o), and papillotubular carcinomas had significantly lower activity than solid tubular and scirrhous carcinomas. However, in group A these data could not be determined. These results suggest that PyNPase activity in group A was possibly decreased by 5'-DFUR.

[Changes in serum intact parathyroid hormone levels and ultrasonic findings after percutaneous ethanol injection therapy in a patient with primary hyperparathyroidism]

A 74-year-old woman with primary hyperparathyroidism and ischemic heart disease was treated with percutaneous ethanol injection into a single parathyroid adenoma which was confirmed by fine-needle aspiration biopsy. The changes in intact parathyroid hormone (int-PTH), serum calcium, serum phosphate, and alkaline phosphatase after percutaneous ethanol injection therapy (PEIT), and also ultrasonic findings of the injected adenoma were examined before and after PEIT. The values of int-PTH and serum calcium remained high for a few hours after the ethanol injection. About 24 hrs later, however, rapid lowering of the serum concentrations of int-PTH and serum calcium was observed, reaching normal levels about 36 hrs later. Although these parameters recurred once, the patient received another three ethanol injections within three months, which normalized these values. In ultrasonic findings, the parathyroid adenoma was well demarcated and hypoechoic before PEIT. Twenty-four hours after the ethanol injection, the adenoma became hyperechoic with a small hypoechoic lesion as viable tissue. Then the tumor shrank gradually and no apparent side-effects was observed in a total of four PEIT. Since in Japan, PEIT for primary hyperparathyroidism has not been widely performed, we propose that this therapy could be a useful alternative treatment in patients in whom parathyroid surgery would not be indicated such as the elderly, patients with high surgical risks, hypercalcemic crisis and patients who refuse surgery.

Effect of glycyrrhizin on cortisol metabolism in humans

Urinary cortisol and cortisone excretion were measured after glycyrrhizin administration (225 mg/day, per os) for seven consecutive days in five healthy volunteers. The ratio of plasma cortisol and cortisone during hydrocortisone (0.6 mg/kg i.v.) infusion was also examined. After glycyrrhizin administration, the urinary cortisone to cortisol ratio was significantly decreased, but the ratio of plasma cortisol to cortisone was not significantly altered. Glycyrrhizin inhibited 11 beta-hydroxysteroid dehydrogenase in the kidney and so inhibited the conversion of cortisol to cortisone. The increased cortisol in the kidney could be the cause of the apparent mineralocorticoid excess syndrome induced by glycyrrhizin.

Effect of DCA administration or endurance training on lactate metabolism in mice during and after exercise

The purpose of this study was to investigate the effect of the activation of tissue oxidative capacity by dichloroacetate (DCA) administration or endurance training on oxidative removal of lactate, which is the major pathway of lactate metabolism, in mice during prolonged exercise and after supramaximal exercise. DCA administration significantly decreased the blood lactate concentration and activated the oxidative removal of lactate during prolonged exercise. DCA administration did not change lactate metabolism in mice after supramaximal exercise. Endurance training significantly decreased the blood lactate concentration during prolonged exercise and also activated the oxidative removal of lactate. Endurance training significantly increased the recovery of the blood lactate concentration after supramaximal exercise, while it did not activate the oxidative removal of lactate. These results suggest that the activation of the tissue oxidative capacity decreases the blood lactate concentration and also can activate the oxidative removal of lactate during prolonged exercise, while it does not activate the oxidative removal of lactate after supramaximal exercise.

Effect of dichloroacetate on oxidative removal of lactate in mice after supramaximal exercise

1. The effect of dichloroacetate (DCA), which activates substrate oxidation on oxidative removal of lactate in mice after supramaximal exercise was investigated. 2. DCA significantly decreased the blood lactate concentration and increased the oxidative removal of lactate during prolonged exercise. 3. No significant differences were found in the removal of the blood lactate concentration, in oxidative removal of lactate after supramaximal exercise. 4. It is concluded that DCA administration which activates lactate oxidation during exercise does not activate lactate oxidation in mice after supramaximal exercise.

Evaluation of clonidine suppression and various provocation tests in the diagnosis of pheochromocytoma

Recent investigations have shown that the widely used clonidine suppression test is sometimes fallible for the diagnosis of pheochromocytoma. A comparative assessment was made of the following suppression and provocation tests, the clonidine suppression test, and the glucagon, metoclopramide, and naloxone provocation tests. The assessment was performed in 6 patients with pheochromocytoma and in 19 patients without pheochromocytoma who were initially suspected of harboring a tumor. BP response did not predict the presence of pheochromocytoma in any test. Plasma norepinephrine (NE) concentrations determined at 120 and 180 min after oral 150 micrograms of clonidine gave false negative results in 2 of the 5 patients with pheochromocytoma tested. Both plasma NE and epinephrine (E) concentrations were measured before and sequentially after each provocative agent. Neither NE nor E responded to 1 mg of glucagon iv in 2 of the 4 patients with pheochromocytoma tested. Determination of the peak level, peak increment, and % peak increment of NE and E following 10 mg of naloxone iv did not distinguish the two groups. The % peak increments of both NE and E in all 4 patients with pheochromocytoma given 5 mg of metoclopramide iv exceeded the mean + 3 SD values of the patients without pheochromocytoma (25 + 28% for NE, and 25 + 42% for E). These results suggested that, when performed with judicious patient selection (ambiguous plasma or urinary catecholamine levels), the measurement of plasma catecholamines in response to metoclopramide can be a useful adjunctive tool in the diagnosis of pheochromocytoma.

Pituitary peptides other than ACTH may not be aldosterone secretagogue in primary aldosteronism

In order to elucidate whether pituitary peptides other than ACTH which are derived from the proopiomelanocortin (POMC) are involved for aldosterone secretion in primary aldosteronism, we administered ovine corticotropin releasing factor (CRF), beta-endorphin and naloxone to seven patients with aldosterone producing adenoma. One hundred micrograms of CRF produced an augmented aldosterone response in patients with aldosteronism, while 500 micrograms of beta-endorphin infusion failed to cause any significant changes in neither normal subjects nor patients. An opioid antagonist, naloxone (10 mg, iv) produced no noticeable change in plasma aldosterone in normal subjects, while it caused a slight increase in patients with primary aldosteronism. Plasma cortisol increased to a similar degree in response to CRF and naloxone in normal subjects and patients. In three patients with isolated ACTH deficiency, neither aldosterone nor cortisol responded to these stimuli. The present results indicate that POMC-derived pituitary peptides other than ACTH are unlikely to participate in the aldosterone secretion in normal subjects or in patients with primary aldosteronism.

Mineralocorticoid and renal receptor binding activity of 21-deoxyaldosterone

Since several aldosterone metabolites are known to be active, we have assessed the mineralocorticoid biological and renal receptor binding activities of the aldosterone metabolites, 21-deoxyaldosterone (21-deoxy-Aldo), 21-deoxytetrahydroaldosterone (21-deoxy-THAldo), and 3 alpha, 5 beta-tetrahydroaldosterone (THAldo). We synthesized these steroids by bioreduction of aldosterone with intestinal bacteria. Mineralocorticoid agonist activity of 21-deoxy-Aldo, 21-deoxy-THAldo and THAldo, determined by bioassay using adrenalectomized rats, was 1-5%, less than 0.01%, and 0.1-0.5% that of aldosterone, respectively. 21-Deoxy-Aldo showed no antagonist activity. The relative affinity in competing with [3H]aldosterone for binding to mineralocorticoid receptors in adrenalectomized rat kidney cytosols was 94%, less than 0.01%, and less than 0.01% that of aldosterone. The relative binding affinity for rat renal glucocorticoid receptors was 23%, less than 0.01%, and less than 0.01% that of dexamethasone, and for corticosteroid-binding globulin 17%, less than 0.01%, and less than 0.01% that of cortisol. These results show that the naturally occurring steroid, 21-deoxy-Aldo, possesses mineralocorticoid agonist activity which is equivalent to that of 11-deoxycorticosterone, and has substantial affinity for rat renal mineralocorticoid and glucocorticoid receptors. The results also implicate the pathophysiological role of 21-deoxy-Aldo as a potential mineralocorticoid in 21-hydroxylase deficiency, where urinary excretion of this steroid is invariably elevated.

Angiotensin II generation in mesenteric arteries in rats: effects of nephrectomy, deoxycorticosterone and dexamethasone

Angiotensin II (ANG II) generation in the mesenteric arteries was studied in four groups of rats: deoxycorticosterone (DOCA)/salt treated, glucocorticoid treated, nephrectomized and control rats. Basal plasma renin activity (PRA) was undetectable in the nephrectomized group and suppressed in the DOCA/salt treated rats, but was increased in the rats treated with glucocorticoid. The Basal plasma ANG II concentration changed comparably with PRA in all four groups of rats. In the control rats, ANG II was released from the mesenteric arteries at a rate of 43.0 +/- 12.0 pg/h, and it was not decreased by nephrectomy. In DOCA/salt rats and glucocorticoid rats, ANG II release significantly decreased to 12.8 +/- 7.1 and 6.9 +/- 1.5 pg/h, respectively. Captopril treatment significantly reduced ANG II release from the mesenteric arteries in both controls and nephrectomized rats, but did not influence ANG II output in DOCA/salt rats or in glucocorticoid treated rats. In nephrectomized rats, captopril lowered blood pressure in association with a significant reduction in the mesenteric ANG II formation. These results indicate that the renal and vascular renin-angiotensin system (RAS) may be independently regulated, and in nephrectomized animals the vascular RAS contributes in part to the maintenance of blood pressure. The present results also suggest that volume expansion per se and/or pharmacological intervention by DOCA and glucocorticoid could modulate vascular ANG II generation.

Possible association of aldosterone producing adenoma and non-functioning adrenal tumor

A 37-year-old woman presented with hyperaldosteronism, suppressed renin levels, and a left adrenal mass on CT scanning. Selective adrenal venous sampling indicated a marked rise of the aldosterone level in the right adrenal vein, while the level in the left vein was low. On laparotomy, an aldosterone producing adenoma (APA) of 12x10x5 mm in size was found in the right adrenal gland and was resected, while the left mass was left in situ. The post-operative course showed normalization of both the clinical and biochemical features of primary aldosteronism, with no sign of recurrence or of enlargement of the remaining adrenal mass in 2.5 years of follow up, suggesting the possible coexistence of a "non-functioning" tumor. This case demonstrates the importance of adrenal venous sampling for the localization of APA particularly since the presence of the APA may be masked by a visualized but unrelated adrenal mass.

Glycyrrhizic acid and its hydrolysate as mineralocorticoid agonist

Mineralocorticoid activity of glycyrrhetinic acid (GR) was studied in vivo (electrical potential difference in rat rectum) and in vitro (brush border Mg2+-HCO3- ATPase in rat small intestine, kidney cytosol binding of GR with and without RU-28362, anti-glucocorticoid compound) in order to clarify the mechanism of mineralocorticoid-like activity of GR. Scatchard analysis of [3H]aldosterone showed that Kd of higher affinity site (type I) 6.0 X 10(-9) M, Bmax 1.0 X 10(-14) mol/mg protein, and Kd of lower affinity site (type II) 1.6 X 10(-7) M, Bmax 7.5 X 10(-14) mol/mg protein. GR competed for [3H]aldosterone binding sites in kidney cytosol at the concentration of 10(4) times as that of unlabeled aldosterone. RU-28362 displaced aldosterone binding curve, whereas GR binding kinetic was not affected by this compound. Adrenalectomy caused a significant fall in brush border Mg2+-HCO3- ATPase activity (75% reduction compared with the initial level) which was not restored by GR administration. Electrical potential differences in the adrenalecomized rats were significantly lower than those in the control rats, which did not increase after GR administration.