Substrate specificity of human 3(20)alpha-hydroxysteroid dehydrogenase for neurosteroids and its inhibition by benzodiazepines

In this report, we compared kinetic constants and products in the reduction of the neurosteroids, 3alpha,5alpha-tetrahydroprogesterone (3alpha,5alpha THP) and 3alpha,5alpha-tetrahydrodeoxycorticosterone (3alpha,5alpha-THDOC), and their precursors, 5alpha-dihydroprogesterone (5alpha-DHP), 5alpha-dihydrodeoxycorticosterone (5alpha-DHDOC) and progesterone, by three isoenzymes (AKR1C1, AKR1C2 and AKR1C3) of human 3alpha-hydroxysteroid dehydrogenase. AKR1C1 efficiently reduced 3alpha,5alpha-THP, 5alpha-DHP and progesterone to their 20alpha-hydroxy metabolites, and slowly converted 5alpha-DHDOC to 3alpha,5alpha-THDOC. AKR1C2 exhibited low 20-ketoreductase activity for 3alpha,5alpha-THP and moderate 3-ketoreductase activity for 5alpha-DHP and 5alpha-DHDOC. 3alpha,5alpha-THDOC was not reduced by the two isoenzymes. No significant activity for the steroids was detected with AKR1C3. The results suggest that AKR1C2 is involved in the neurosteroid synthesis, but AKR1C1 decreases the neurosteroid concentrations in human brain by inactivating 3alpha,5alpha-THP and eliminating the precursors from the synthetic pathways. In addition, we found that the several benzodiazepines inhibited the three isoenzymes noncompetitively with respect to the substrate. Although cloxazolam was a potent and specific inhibitor of AKR1C3, diazepam, estazolam, flunitrazepam, medazepam and nitrazepam, that inhibited AKR1C1 and AKR1C2, may influence the neurosteroid metabolism.     

Amyloid forming proteases: therapeutic targets for Alzheimer's disease

Alzheimer's disease is an age-related neurodegenerative disease which causes global loss of cognitive function. Drug treatment for Alzheimer's disease has been limited to agents that ameliorate behavioral symptoms but these agents are without effect on disease progression. Rational drug design for the treatment of Alzheimer's disease now seems possible. As a result of major advances in medical research in this area, knowledge of the etiology of Alzheimer's disease is rapidly being understood. This information has uncovered relevant and novel targets for treatment. At the center of the etiological progression of this disease is beta-amyloid. A substantial body of evidence strongly suggests that this small protein is critical to the development of Alzheimer's disease. The beta-amyloid protein is generated by two different proteolytic cleavages. Recently, the proteases responsible for producing the beta-amyloid protein have been identified. The proteases represent viable targets for therapeutic intervention against Alzheimer's disease. In this review, we describe the biological characteristics of the beta-amyloid-forming proteases in the context of pharmaceutical development.     

Protective effect of neurotropin against lipopolysaccharide-induced hypotension and lethality linked to suppression of inducible nitric oxide synthase induction

Neurotropin is a non-protein extract from the dermis of rabbits inoculated with vaccinia virus and has been clinically used as an analgesic in Japan. We present in the current report evidence for its potential therapeutic value against endotoxin shock. Administration of this compound prior to lipopolysaccharide (LPS) challenge resulted in a reversal of a decrease of the mean arterial pressure in rats and also amelioration of lethality in mice. Anti-inducible nitric oxide synthase (iNOS) Western blotting of tissue extracts from LPS-treated mice revealed almost complete suppression of iNOS induction by Neurotropin. The findings in vivo were reproduced in in vitro experiments in which cultured human umbilical vascular endothelial cells were challenged with LPS. Simultaneous treatment of the cells with Neurotropin resulted in complete suppression of iNOS induction and significant reduction of cell death. These results suggested a therapeutic value of Neurotropin in the treatment of endotoxin shock that was linked, at least in part, to suppression of iNOS induction and reduced cell damage in vascular endothelial cells.     

Clinical analysis of 16 cases of malignant head and neck melanoma

Subjects were 16 patients--5 men and 11 women aged 46-82 years (mean: 61 years)--with malignant melanoma of the head and neck treated at our clinic from 1972 to 1988. Histologically, 1 subjects was amelanotic and 15 melanotic type. Primary lesions were 10 involving the nasal cavity, 2 the paranasal sinus, 2 the gingiva, 1 the lip, and 1 primary unknown. They were treated with or without multimodal surgery, radiation, chemotherapy, and immunotherapy. Of 12 treated using local surgery, local recurrence was seen in 6 in 7 areas. Two-year survival was 44% and 5-year survival 22%. The prognosis of malignant head and neck melanoma is poor but has gradually improved due to preoperative decisions on disease spread and the introduction of multimodal therapy.     

Nitric oxide increases glucose uptake through a mechanism that is distinct from the insulin and contraction pathways in rat skeletal muscle

Insulin, contraction, and the nitric oxide (NO) donor, sodium nitroprusside (SNP), all increase glucose transport in skeletal muscle. Some reports suggest that NO is a critical mediator of insulin- and/or contraction-stimulated transport. To determine if the mechanism leading to NO-stimulated glucose uptake is similar to the insulin- or contraction-dependent signaling pathways, isolated soleus and extensor digitorum longus (EDL) muscles from rats were treated with various combinations of SNP (maximum 10 mmol/l), insulin (maximum 50 mU/ml), electrical stimulation to produce contractions (maximum 10 min), wortmannin (100 nmol/l), and/or the NO synthase (NOS) inhibitor NG-monomethyl-L-arginine (L-NMMA) (0.1 mmol/l). The combinations of SNP plus insulin and SNP plus contraction both had fully additive effects on 2-deoxyglucose uptake. Wortmannin completely inhibited insulin-stimulated glucose transport and only slightly inhibited SNP-stimulated 2-deoxyglucose uptake, whereas L-NMMA did not inhibit contraction-stimulated 2-deoxyglucose uptake. SNP significantly increased the activity of the alpha1 catalytic subunit of 5'AMP-activated protein kinase (AMPK), a signaling molecule that has been implicated in mediating glucose transport in fuel-depleted cells. Addition of the NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME) (1 mg/ml) to the drinking water of rats for 2 days failed to affect the increase in muscle 2-deoxyglucose uptake in response to treadmill exercise. These data suggest that NO stimulates glucose uptake through a mechanism that is distinct from both the insulin and contraction signaling pathways.     

Preliminary retrospective investigation of FDG-PET/CT timing in follow-up of ablated lung tumor

OBJECTIVE: The aim of this study was to clarify the most appropriate follow-up initiation time point for positron emission tomography (PET)/computed tomography (CT) following radio frequency ablation (RFA) of lung tumors, and the cutoff values of maximum standard uptake value (SUV(max)) to evaluate local tumor progression. METHODS: We enrolled 15 patients (8 men, median age 62 years) with 60 tumors, who were treated with RFA of lung tumors and underwent fluorodeoxyglucose (FDG)-PET/CT following RFA. Local tumor progression was assessed by periodic chest CT images prior to and following intravenous administration of a contrast medium. The SUV(max) of three periods, namely, 0-3 months, 3-6 months, and 6-9 months after RFA, was evaluated. The appropriate time point for follow-up initiation and the cutoff value of SUV(max) were determined using receiver-operating characteristic (ROC) analysis. RESULTS: The median follow-up period was 357 days. Of 60 tumors, 10 showed local progression. The area under the ROC curve (Az) for the 6-9 months (P = 0.044) was the largest and almost equal to that of the 3-6 months (P = 0.024). Az for the 0-3 months was the smallest and statistically insignificant (P = 0.705). The cutoff value of 1.5 of SUV(max) at 3-9 months after RFA showed 77.8% sensitivity and 85.7-90.5% specificity. CONCLUSIONS: The appropriate follow-up initiation time point is at least 3 months following RFA. Thus, SUV(max) is a useful and reliable predictive indicator.     

Usefulness and limitations of the Japan Mammography Guidelines for the categorization of microcalcifications

Background  The Japan Mammography Guidelines, referred to the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS), are intended to standardize the terminology in mammographic reports and the assessment of findings and to recommend action to be taken. The Japan Mammography Guidelines have explicit guidelines for the categorization of microcalcifications. The purpose of this study was to assess the positive predictive value (PPV) of each categorization of microcalcifications according to the decision table proposed by the Japan Mammography Guidelines according to BI-RADS morphology and distribution parameters and the pathologic outcome. Methods  A retrospective review was performed of 101 non-palpable screening mammography-detected microcalcification lesions without mass that had stereotactic vacuum-assisted breast biopsy (SVAB). This study was approved by our institutional review board, and informed consent was obtained for all SVAB. We classified microcalcification lesions according to the decision table. Histological findings were reviewed. Results  In calcification morphology, all 32 punctate morphology microcalcifications, regardless of distribution, were benign (100%), whereas 25% (9/36) amorphous morphology microcalcifications, 67% (14/21) pleomorphic morphology microcalcifications and 92% (11/12) linear morphology microcalcifications were malignant. For calcification distribution, 28% (15/55) cluster distribution microcalcifications, 40% (17/43) segmental distribution microcalcifications and 67% (2/3) linear distribution microcalcifications were malignant. Features with high positive PPV showed segmental or linear distribution of linear morphology (100%, respectively), segmental distribution of pleomorphic morphology (100%) and cluster distribution of linear morphology (80%). The PPV for cluster punctate, cluster amorphous, cluster pleomorphic and cluster linear microcalcifications was 0, 21, 50 and 80%, respectively. The PPV for segmental punctate, segmental amorphous, segmental pleomorphic and segmental linear microcalcifications was 0, 27, 100 and 80%, respectively. The PPV for linear amorphous and linear linear microcalcifications was 50 and 100%. Conclusions  The decision table proposed by the Japan Mammography Guidelines according to BI-RADS morphology and distribution parameters is useful, but continued development of the decision table to improve standardization in mammographic interpretation is needed.     

A novel mutation in the GATA3 gene in a family with HDR syndrome (Hypoparathyroidism, sensorineural Deafness and Renal anomaly syndrome)

We report here on a girl and her father with HDR syndrome (Hypoparathyroidism, sensorineural Deafness and Renal anomaly syndrome). The proband, an 11 year-old girl, complained of periodic tetany lasting for 6 years, and also used a hearing aid because of sensorineural hearing impairment. Furthermore, she had hemimegalencephaly, and had been taking an anti-epileptic agent to treat psychomotor seizures for 6 years. Endocrine assessment showed modest hypocalcemia, hyperphosphatemia and hypophosphaturia with lower normal parathyroid hormone concentration, and she had no renal abnormalities. Her father, who was 40 years old at the time of the investigation, had sensorineural hearing impairment, a lower than normal calcium level and normal renal function. Direct sequencing after PCR amplification of genomic DNA revealed a novel insertional mutation (405insC) in the GATA3 gene of both patients. This mutation was hypothesized to disrupt dual zinc fingers as well as one transactivating domain. The present findings lend additional support to the notion that the phenotype cannot be precisely estimated from the genotype in HDR syndrome.     

FDG-PET of autoimmune-related pancreatitis: preliminary results

The purpose of this retrospective study was to elucidate the fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) findings in autoimmune-related pancreatitis (AIP), which is a reversible chronic pancreatitis with an autoimmune cause. The study group comprised six patients with clinically diagnosed AIP. After 370 MBq (10 mCi) of FDG had been injected intravenously, the abdomen and/or the whole body was scanned at 1 h post injection in all patients, and scanning was repeated at 2 h in four patients. PET findings were evaluated visually and/or semiquantitatively using the standardized uptake value (SUV). In four of the six patients, PET demonstrated intense uptake in the whole pancreas, which appeared swollen on computed tomography, and the accumulation increased with time in three patients. In one patient, intense focal uptake in the pancreatic head was observed, and the accumulation decreased over time. In the remaining patient, no abnormal accumulation in the pancreas was observed. Follow-up PET scanning after steroid therapy was performed in three patients, and intense FDG uptake was no longer observed. Our preliminary data show that AIP can cause intense FDG uptake in the pancreas. This fact, and the benign status of the condition, should be kept in mind when making a diagnosis with FDG-PET in patients with pancreatic disorders.