Development of the hepatic mixed function oxidase system in a marsupial, the quokka (Setonix brachyurus).

The development of the mixed function oxidase system has been studied in pouched and young-at-heel joey quokkas. Cytochrome P-450 was first detectable at 35 days, rose sharply to one-third of the adult level by 53 days, and reached levels in the adult range between 155 and 255 days. NADPH-Cytochrome c reductase was approximately one-fifth the adult level at 45 days and , by 80–105 days of life, had reached values within the range for adult animals. Benzpyrene hydroxylase activity was barely detectable at 35 days; its development lagged behind that of the components of the cytochrome P-450 system and adult levels were not seen until 200 days. Electron microscopy showed that hepatocytes in 20- and 35-day joeys contained some short chains of rough endoplasmic reticulum. Areas of smooth endoplasmic reticulum were first evident at 45 days and at subsequent stages (80, 100, and 150 days and adult) increasing concentrations of both smooth and rough endoplasmic reticulum were present. Development of the mixed function oxidase system in the quokka liver is slow and resembles more closely the pattern of development in human fetal liver than that in many common laboratory animals.     

Identification of transmembrane domain 6 & 7 residues that contribute to the binding pocket of the urotensin II receptor

Urotensin II (U-II), a cyclic undecapeptide, is the natural ligand of the urotensin II (UT) receptor, a G protein-coupled receptor. In the present study, we used the substituted-cysteine accessibility method to identify specific residues in transmembrane domains (TMDs) six and seven of the rat urotensin II receptor (rUT) that contribute to the formation of the binding pocket of the receptor. Each residue in the R256^(6.32)-Q283^(6.59) fragment of TMD6 and the A295^(7.31)-T321^(7.57) fragment of TMD7 was mutated, individually, to a cysteine. The resulting mutants were expressed in COS-7 cells, which were subsequently treated with the positively charged methanethiosulfonate-ethylammonium (MTSEA) or the negatively charged methanethiosulfonate-ethylsulfonate (MTSES) sulfhydryl-specific alkylating agents. MTSEA treatment resulted in a significant reduction in the binding of TMD6 mutants F268C^(6.44) and W278C^(6.54) and TMD7 mutants L298C^(7.34), T302C^(7.38), and T303C^(7.39) to ¹²⁵I-U-II. MTSES treatment resulted in a significant reduction in the binding of two additional mutants, namely L282C^(6.58) in TMD6 and Y300C^(7.36) in TMD7. These results suggest that specific residues orient themselves within the water-accessible binding pocket of the rUT receptor. This approach, which allowed us to identify key determinants in TMD6 and TMD7 that contribute to the UT receptor binding pocket, enabled us to further refine our homology-based model of how U-II interacts with its cognate receptor.     

ENDOTHELIN IS BLOOD VESSEL SELECTIVE: STUDIES ON A VARIETY OF HUMAN AND DOG VESSELS IN VITRO AND ON REGIONAL BLOOD FLOW IN THE CONSCIOUS RABBIT

1. Endothelin (Et), a vasoconstrictor peptide, was 5-10-fold more potent (lower EC50) on isolated ring segments of large veins than on large arteries removed from dog coronary, mesenteric, femoral, renal and internal mammary vasculature and from the human internal mammary pedicle. 2. In the dog large coronary artery, Et (10-30 nmol/L) caused transient relaxations partway through the generation of a concentration-contraction curve. These relaxations were endothelium dependent. 3. In conscious rabbits treated with mecamylamine, Et (0.025-0.4 nmol/kg) caused a marked rise in renal vascular resistance but hindquarter vasodilation. Under the same conditions angiotensin II constricted both beds. 4. These studies suggest that Et is vascular bed and large vein selective in activity. It did not appear to be selective for large or small coronary arteries in vitro.     

Ca2+/calmodulin-dependent protein kinase II immunoreactivity in Lewy bodies

Summary Ca²⁺/calmodulin-dependent protein kinase II (CaM kinase II) is one of the predominant protein kinases in the brain. We found that CaM kinase II immunoreactivity was concentrated in the peripheral halos of Lewy bodies (LBs) in Parkinson's disease and Lewy body-like hyaline inclusions (LBHIs) in amyotrophic lateral sclerosis. An immunoelectron microscopic examination of LBs revealed that the filaments at the periphery of LBs were decorated with immunopositive deposits. Since CaM kinase II has a broad substrate specificity and can phosphorylate neurofilaments and other cytoskeletal proteins, it may play some role in the formation of LBs and LBHIs through the aberrant phosphorylation of the cytoskeletal elements in these inclusions.Supported by a Grant-in-Aid for Scientific Research on Priority Areas, No. 02240104, from the Ministry of Education, Science and Culture, Japan     

Inhibition by Brain Natriuretic Peptide of Vasopressin Neurons in the Supraoptic Nucleus and Neurons in the Region of the Anteroventral Third Ventricle in Rat Hypothalamic Slice Preparations

It is not entirely clear whether or not atrial natriuretic peptide (ANP) directly inhibits vasopressin neurons in the supraoptic nucleus (SON) and paraventricular nucleus. Recently, a novel peptide, brain natriuretic peptide (BMP), which has been isolated from the brain, has been shown to have a similar action to ANP on the regulation of vasopressin release. Intracerebroventricular injection of both BNP and ANP inhibits stimulus-evoked increases of plasma vasopressin level. The present study was undertaken: 1) to investigate whether BNP affects the activity of neurons in the region of the anteroventral third ventricle (AV3V) and SON which are involved in the control of body fluid homeostasis and blood pressure regulation, 2) to reassess effects of ANP on SON neurons, and 3) to test whether BNP exerts its effects by mechanisms which are different from those of ANP. Extracellular recordings were made from 213 AV3V and 110 SON spontaneously firing neurons in the rat coronal hypothalamic slice preparation. Of the AV3V neurons tested, BNP inhibited 86 (40%) and excited 2 (1%) while 125 neurons remained unaffected. A dose-response relationship was obtained for 7 AV3V neurons at different BNP concentrations ranging from 10^?11 M to 10^?6 M; the firing rates of all 7 neurons decreased. The threshold concentration to evoke inhibitory responses was approximately 10^?10M in the AV3V. When BNP and ANP were applied to the same neuron, most AV3V neurons which were inhibited by BNP were also inhibited by ANP and the neurons which were unaffected by BNP were also unaffected by ANP. Thus, these two peptides probably have a similar action on AV3V neurons. When BNP and angiotensin II were applied to a group of 60 neurons in the AV3V, most of the responsive neurons showed either inhibitory responses to BNP or excitatory responses to angiotensin II. Both BNP and ANP were applied to a group of 110 SON neurons: BNP (10 ^?7 M) inhibited 52 (75%) of 69 phasic (putative vasopressin) neurons, while BNP affected none of the 41 non-phasic (putative oxytocin) neurons. By contrast, ANP inhibited only 20 (29%) of 69 phasic neurons tested but it also had no effect on 41 non-phasic neurons tested. Our results are consistent with the suggestion that BNP is involved in the regulation of vasopressin release by acting on SON neurons and AV3V neurons.     

Specific binding of angiotensin II and atrial natriuretic factor in non-nephropathic type I diabetes mellitus

We examined ten patients with type I diabetes mellitus and ten age- and sex-matched healthy controls. Median duration of diabetes was 7 years (range 0.5-24). None of the diabetic patients had hypertension, microalbuminuria, or proliferative retinopathy. Maximal specific binding capacity for angiotensin II to thrombocytes was significantly increased in diabetics (Bmax 11.9 +/- 1.6 sites per cell vs 7.0 +/- 0.9 in controls; P less than 0.01). In contrast, maximal binding for atrial natriuretic factor tended to be lower in type I diabetics (8.84 +/- 1.25 sites per cell vs 16.8 +/- 2.97; P less than 0.07). There was no difference of apparent dissociation constant (KD) for either receptor. Angiotensin II values (RIA) were greater in diabetics (16.2 +/- 1.5 pg/ml vs 8.5 +/- 1.4 in controls; P less than 0.02) and concentrations of atrial natriuretic factor (RIA) were not significantly different. The data suggest increased angiotensin II binding despite high angiotensin II concentrations in non-nephropathic type I diabetic patients. These findings may be relevant when considering the evolution of hypertension and microangiopathy lesions.     

Characterization of prolidase activity in erythrocytes from a patient with prolidase deficiency: comparison with prolidase I and II purified from normal human erythrocytes

OBJECTIVES: The purpose of this study was to investigate the effect of various amino acids and their metabolites on the activities of prolidase I and II from human erythrocytes compared to those in a patient with prolidase deficiency. DESIGN AND METHODS: Prolidase I and II from human erythrocytes were purified by using column chromatography. Prolidase activity against various iminodipeptides was determined by spectrophotometry using Chinard's method. RESULTS: The activities of prolidase I and II against glycylproline and methionylproline were enhanced by glycine, L- and D-isoforms of alanine and serine and D-isoforms of valine, leucine and isoleucine. L-isoforms of branched amino acids inhibited the activity of prolidase I. On the other hand, the activity of prolidase II was enhanced by all of these L-branched amino acids. The patient's prolidase activity was also enhanced by all the L- and D-branched amino acids. CONCLUSION: The activities of prolidase I and II against various iminodipeptides were prominently enhanced by glycine, but the effect of L-valine differed between the two enzymes. Enzymatic properties of the patient's prolidase were essentially the same as those of prolidase II.     

Surgical versus nonsurgical management for type II odontoid fractures in the elderly population: a systematic review

Background

Odontoid process fractures, of which type II constitute the majority, are an increasingly important cause of morbidity and mortality in the elderly population. The incidence of geriatric type II fractures is steadily increasing in line with the aging population. However, the decision between surgical and non-surgical intervention for type II fractures in the elderly remains controversial.

Lack of efficacy of Lactobacillus GG in reducing pulmonary exacerbations and hospital admissions in children with cystic fibrosis: A randomised placebo controlled trial

Background

Intestinal dysbiosis has been described in Cystic Fibrosis (CF) and probiotics have been proposed to restore microbial composition. Aim of the study was to investigate the effects of Lactobacillus rhamnosus GG (LGG) on clinical outcomes in children with cystic fibrosis (CF).

The prevalence of migraine in patients with bipolar and unipolar affective disorders

There is a well-known association between migraine and affective disorders, but the information is sparse concerning the prevalence of migraine in subgroups of the affective disorders. The present study was undertaken to investigate the prevalence of migraine in unipolar depressive, bipolar I and bipolar II disorders. Patients with major affective disorders (n = 62), consecutively admitted to an open psychiatric ward, were examined with a semi-structured interview based on DSM-IV diagnostic criteria, combined with separate criteria for affective temperaments. Diagnosis of unipolar and bipolar I disorders followed the DSM-IV criteria, while bipolar II disorder encompassed patients with either discrete hypomanic episodes or a cyclothymic temperament. Migraine was diagnosed according to IHS-criteria. Symptoms of migraine were found to be common in these patients, both in those with unipolar depression (46% prevalence of migraine) and in those with bipolar disorders (44% prevalence). Among the bipolar patients there was, however, a striking difference between the two diagnostic subgroups, with a prevalence of 77% in the bipolar II group compared with 14% in the bipolar I group (P = 0.001). These results support the contention that bipolar I and II are biologically separate disorders and point to the possibility of using the association of bipolar II disorder with migraine to study both the pathophysiology and the genetics of this affective disorder.