Antiulcerogenic mechanisms of dehydrocrotonin, a diterpene lactone obtained from Croton cajucara.

The bark of Croton cajucara Benth, is used in Brazilian folk medicine as an infusion to treat gastrointestinal disorders. The aim of the present study was to assess the mechanisms involved in the antiulcerogenic activity of dehydrocrotonin (DHC), a diterpene isolated from C. cajucara bark. We studied the effects of DHC on pylorus ligature (Shay) in mice treated with the drug (100 mg/kg) by the intraduodenal route. DHC did not induce any alteration in gastric volume in Shay mice but modified the pH and total acid concentration of gastric juice. Incubation of gastric juice with DHC did not reduce gastric acidity compared to control. We also investigated the effects of DHC on the response to histamine of right atria isolated from guinea pigs and on the response to carbachol of stomach fundus strips from rats. The concentration-response curves for the chronotropic effect of histamine in guinea pig right atria were shifted to the right, with a significant decrease in the maximum response, in the presence of DHC. Similar results were obtained with DHC (30 microM) for the concentration-response curves to carbachol in the isolated rat stomach. The ability of DHC to increase PGE2 release from rat stomach mucous cells was also studied. We observed that DHC induced a significant increase in PGE2 production (60% compared to control). In addition, the effects of DHC on the healing of acetic acid-induced gastric ulcer in rats were evaluated 14 days after acid injection. Oral administration of DHC (100 mg/kg per day) for 14 consecutive days had no effect on gastric ulcer healing in rats. Thus, the protective effect of DHC on induced gastric lesions could be due to synergistic effects, e.g., an increase in PGE2 release and non-competitive antagonism of H2-receptors and of muscarinic receptors. Whereas the former result represents an increase in the protective factors, the latter one shows a decrease in the aggressive factors against the gastric mucosa.     

PREVALENCE OF MICROALBUMINURIA IN NON-INSULIN-DEPENDENT DIABETES MELLITUS

The prevalence of microalbuminuria was assessed in 50 patients of non-insulin dependent diabetes mellitus. The mean age of patients was 52.1 ± 11.6 years and the duration of diabetes was 8.3 ± 6.8 years. Twenty (40%) patients had microalbuminuria. Microalbuminuria was more common in patients with a longer duration of diabetes (more than 5 years), a poor glycaemic control, and higher systolic blood pressure.KEY WORDS: Microalbuminuria, Diabetes mellitus, Diabetic nephropathy, Chronic renal failure     

Memory and the septo-hippocampal cholinergic system in the rat

This study examined the effects of intrahippocampal injections of scopolamine (a muscarinic antagonist drug) on performance of a working-memory task (contingently) reinforced T-maze alternation) and a reference-memory task (visual discrimination) by the same rats in the same maze. Rats in the first shipment were trained in delayed alternation, received bilateral implantation of cannulae aimed at the CA3 field of the dorsal hippocampus, and were tested for retention with 1 l microinjections of scopolamine (35 g) and saline on alternate days. These rats were then trained on visual discrimination and tested alternately under scopolamine or saline as described above. It was found that scopolamine impaired performance of delayed alternation to a greater extent than performance of visual discrimination. Data from rats in the second shipment replicated this finding, with the order of the tasks reversed, and, additionally, showed that delayed alternation, but not visual discrimination, was impaired at a dose of 12 g/l. A dose of 4 g/l had no effect on either task. It is concluded that performance of a workingmemory task is significantly more sensitive to disruption of cholinergic mechanisms in the hippocampus than performance of a reference-memory task.Supported by PHS Training Grant MH-14577. Now at the Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA     

The use of tapioca as coverage in viral titration]

Virus titration is an important step required on viral vaccines quality control. "Plaque assay", which employs several types of overlay media, is usually used on viral titrations. In this paper we describe the use of Tapioca as an overlay media. Firstly, the toxicity of Tapioca was tested on Vero cells inoculated or not with the Yellow Fever virus (YF) 17DD vaccine strain. Secondly, different batches of the 17DD virus using the Tapioca and Karaya gum as the overlay on Vero cells were tested when higher titres were obtained using Tapioca. Tapioca was also shown to be a suitable overlay to be used in thermostability and plaque reduction neutralization tests. Other systems could benefit from the use of Tapioca as an overlay, since it was possible to titer Measles virus in Vero cells. Tapioca is a cheap Brazilian product, is locally available, easy to use, and reliable. Its use is suggested.     

Efficacy of Zoladex LA (goserelin) in the treatment of girls with central precocious or early puberty

OBJECTIVE: To assess the efficacy of a longer acting preparation of the gonadotrophin releasing hormone (GnRH) analogue goserelin (Zoladex LA, 10.8 mg) in 12 girls with central precocious or early puberty. METHODS: Two girls started treatment de novo; the remainder had been on suppressive treatment for a median duration of 1.5 (range, 0.2-5.6) years. Assessment comprising auxology, pubertal staging, and pelvic ultrasound examination was carried out at weeks 0, 4, 8, 10, and 12 (first cycle) and weeks 8, 10, and 12 (second cycle) to evaluate the required injection frequency. Thereafter, assessment was performed on the day of injection. Zoladex LA was given every 12 weeks unless pubertal progression occurred. RESULTS: Satisfactory control was achieved in eight patients using this regimen, and three patients required more frequent injections. One girl was removed from the study because of clinical progression and extreme mood swings. No serious adverse effects occurred. Mean height velocity during the study period was 4.5 cm/year (range, 3.1-6.6) compared with 6.5 cm/year (range, 3.8-9.6) before treatment in nine patients for whom data were available. CONCLUSIONS: Zoladex LA was effective in controlling precocious puberty in girls when given at intervals of 9-12 weeks and it is recommended that an initial assessment is made eight weeks after beginning treatment.     

Beta2 integrin/ICAM-1 adhesion molecule interactions in cutaneous inflammation and tumor promotion

The beta2 integrin (CD 18/CD 11 a, b, c) family of proteins mediate adherence of leukocytes to vascular endothelium and the associated ligand, intercellular adhesion molecule-1 (ICAM-1; CD 54), interacts with beta2 integrin proteins to allow transendothelial migration of leukocytes into sites of inflammation. The present study examines the function of these proteins in a murine model of acute cutaneous inflammation induced following topical application of 12-O- tetradecanoylphorbol-13-acetate (TPA) to the dorsal epidermis of SENCAR mice and in a model of skin multistage carcinogenesis. At 24 h following topical application of TPA to the dorsal epidermis of mice, dermal leukocytes expressed higher levels of beta2 integrin protein compared with the lower levels of beta2 integrin protein expression by peripheral blood leukocytes. ICAM-1 protein was localized to epidermal keratinocytes and vascular endothelium in TPA-treated skin and to proliferating papilloma cells. Intravenous (i.v.) injection of either 50 microg anti-beta2 integrin antibody alone or in combination with anti-ICAM-1 antibody significantly inhibited both TPA-stimulated neutrophil infiltration into the dermis (P < 0.001) and myeloperoxidase (MPO) activity (P < 0.03 anti-beta2 integrin antibody; P < 0.01 anti- beta2 integrin + ICAM-1 adhesion molecule antibodies), but had no effect on TPA-induced epidermal hyperplasia. In addition, injection of either anti-ICAM-1 adhesion molecule antibody alone (P < 0.004) or in combination with anti-beta2 integrin antibody (P < 0.001) significantly inhibited TPA-induced production of 7,8-dihydroxy-2'-deoxyguanosine (8- OHdG) immunoreactive proteins by epidermal keratinocytes. Beta2 integrin/ICAM-1 adhesion molecules work in concert to regulate migration, retention and functional activation of leukocytes within the dermis during TPA-induced skin inflammation and within stromal tissue of papillomas that form during multi-stage carcinogenesis. Agents that inhibit these receptor/ligand interactions may be useful in defining the roles of specific cell populations in cutaneous inflammation and multistage carcinogenesis and may also have potential as anti-promoting and anti-progression agents.      

Mutation of the p53 tumor suppressor gene in spontaneously occurring osteosarcomas of the dog

Inactivation of the p53 tumor suppressor gene has been implicated in the pathogenesis of numerous human cancers, including osteosarcomas. Appendicular osteosarcomas of the dog appear to be a good model for their human equivalent with regard to biologic behavior, epidemiology and histopathology. We individually screened exons 5-8 of the p53 gene for mutations in 15 canine appendicular osteosarcomas using 'Cold' SSCP to compare the role of this gene in human and canine osteosarcoma tumorigenesis. Seven of the tumors (47%) exhibited point mutations, with one tumor possessing two mutations within different exons. Of these, seven were missense mutations and the eighth was a 'silent' mutation potentially affecting the exon 6-7 splicing region. Five of the missense mutations were located in highly conserved regions IV and V, while another corresponded with the highly conserved codon 220 mutational hotspot located outside the conserved domains. The locations and types of mutations were nearly identical to those reported in human cancer. These findings provide strong evidence of the involvement of p53 mutations in the development of canine appendicular osteosarcomas. Canine osteosarcomas appear to be a promising model for their human equivalent on a clinical, pathologic, and molecular level.      

SOMATIC NEUROPATHY IN DIABETES MELLITUS

One hundred patients of Diabetes Mellitus (70 with and 30 without clinical somatic neuropathy) were studied to correlate clinical severity with the magnitude of nerve conduction abnormalities. Age range was 10-79 years (mean 49) with equal number of males and females. Incidence of neuropathy was more in patients over 40 years of age (60 out of 70 patients) with duration of disease over two years (78.33%). The grades of severity were mild in 22 (31.33%), moderate in 25 (35.71%) and severe in 23 (32.86%) patients. Nerve conduction studies were carried out in 48 (27 with and 21 without clinical neuropathy) patients, using the apparatus Dantec (Cantata TM). The nerves (median, peroneal and sural) were stimulated at two points and the recording of latency; amplitude (micro V) and motor and sensory nerve conduction velocities (m/s) were done under identical environmental conditions. Sensory nerve conduction velocity was more affected than motor velocity. In the 21 patients without clinical neuropathy, 14 showed abnormalities indicating early involvement of peripheral nerves. Reduction of motor nerve conduction velocity was more in patients with moderate and severe grades. The reduction was more in lower than in upper limbs. Nerve conduction abnormality helps in diagnosis in diabetic neuropathy even in preclinical state and correlates with severity, in clinical neuropathy.KEY WORDS: Diabetic neuropathy, Nerve conduction abnormality, Peripheral neuropathy