Role of renal prostaglandin E2 in two-kidney, one-clip renovascular hypertension in rabbits

To investigate the role of renal prostaglandin E2 (PGE2) in renovascular hypertension, urinary PGE2 was measured in rabbits with hypertension produced by left renal artery constriction. In the acute phase of renovascular hypertension (1 week after the constriction), urinary excretions of PGE2 and sodium were significantly increased without correlations with changes in the systemic blood pressure (delta BP). In this phase, delta BP was directly proportional to plasma renin activity and plasma aldosterone concentration (p less than 0.001). In the intermediate phase (5 weeks), delta BP lost significant correlations with plasma renin activity and plasma aldosterone concentration and had a inverse correlation with urinary sodium excretion (p less than 0.01). In the maintenance phase (10 weeks), delta BP showed inverse correlations (p less than 0.01) with both PGE2 and sodium excretions, although their excretions decreased to normal levels. In the clipped kidney, only urinary PGE2 excretion in the acute phase was significantly elevated (p less than 0.02), and both sodium and PGE2 excretions were significantly decreased (p less than 0.01) in the maintenance phase. In the nonclipped kidney, urinary PGE2 and sodium excretions were elevated in the acute and intermediate phases, but decreased to the control levels in the maintenance phase. In this phase, delta BP showed inverse correlation (p less than 0.01) with both PGE2 and sodium excretions from the nonclipped kidney. The infusion of saralasin, an angiotensin II analogue, dose dependently reduced the blood pressure in the acute phase, but showed no effect in the intermediate and maintenance phases.(ABSTRACT TRUNCATED AT 250 WORDS)     

Identification of the coat protein gene of bean golden mosaic geminivirus

An open-reading frame designated 1R1, on DNA component 1 of bean golden mosaic geminivirus (BGMV), has been identified as the coat protein gene. A DraI restriction fragment of BGMV DNA1 that includes 1R1 was inserted into the SmaI pKK223-3 expression vector. The 32 kD protein expressed in Escherichia coli cells reacted with antibodies to the BGMV capsid polypeptide and behaved identically to purified capsid protein in western blots.     

Effects of compressive loading on biomechanical properties of disc and peripheral tissue in a rat tail model

Intervertebral disc degeneration induced by mechanical compression is an important issue in spinal disorder research. In this study, the biomechanical aspect of the rat tail model was investigated. An external loading device equipped with super-elastic TiNi springs was developed to apply a precise load to the rat tail. By using this device, rat tail discs were subjected to compressive stress of 0.5 or 1.0 MPa for 2 weeks. Discs in the sham group received an attachment of the device but no loading. After the experimental period, first the intact tail with peripheral tissues (PT) such as tendon and skin and then the retrieved disc without PT were subjected to a uniaxial tension–compression test; biomechanical characteristics such as range of motion (ROM), neutral zone (NZ), and hysteresis loss (HL) were evaluated. Furthermore, the load-bearing contribution of PT in the intact tail was estimated by comparing the load–displacement curves obtained by the mechanical tests performed with and without PT. The experimental findings revealed that the continuous compressive stress induced reduction in disc thickness. The intact tail demonstrated decreases in ROM and NZ as well as increases in HL. On the other hand, the retrieved disc demonstrated increases in ROM, NZ, and HL. Further, a significant increase in the load-bearing contribution of PT was indicated. These findings suggest that the load-bearing capacity of the disc was seriously deteriorated by the application of compressive stress of 0.5 or 1.0 MPa for 2 weeks.     

Transplantation of ventral forebrain cholinergic neurons to the hippocampus ameliorates impairment of radial-arm maze learning in rats with AF64A treatment

Two types of cholinergic neurons were transplanted into the hippoccampus of adult rats chemically damaged by lateral ventricular administration of AF64A, a cholinergic neurotoxin, and the effects were compared with respect to their ability to reinnervate the hippocampus and to repair behavioral deficit. Pieces of brain tissue containing the nucleus basalis magnocellularis (NBM) or the striatum were taken for grafting from 17-day rat fetuses. About 3 months after transplantation, the rats with bilateral NBM grafts showed significant amelioration in radial-arm maze performance and habituation to a novel environment in an open field box, although they had not recovered to the control level. In rats with NBM grafts that showed a good performance, there were surviving grafts and many ingrowths of AChE-positive fibers in the hippocampus. By contrast, rats with striatal grafts showed hardly any significant improvement in these behavioral measures. The AChE staining revealed poor outgrowth of the striatal grafts into the hippocampus. These results indicate that grafting of NBM cholinergic neurons, which are anatomically similar to septal neurons, into the hippocampus produces a partial restorative effect on the cognitive impairment associated with hypofunction of the septohippocampal system.     

Best medical practice: the case of Japan.

'Best medical practice' can be given three different definitions. Definition A, by the medical profession, emphasizes the maintenance of technical standards in diagnosis and treatment. Definition B, by the essentially healthy general population, emphasizes preventive measures and the reassurance of the healthy status. Definition C, by the chronically sick and disabled, emphasizes rehabilitation and nursing care. Although each has its inherent weakness, each could be said to be describing an essential but distinct aspect of comprehensive health care which can be utilized to legitimize each party's claim for priority in the allocation of resources. Thus, the relative weight that is given to the three definitions of 'best medical practice' in society as a whole appears to be ultimately dependent on the social and cultural conditions unique to each country. In the case of Japan, Definition B has become the most dominant: it has resulted in the health care demands of the essentially healthy general population being well taken care of without excessive allocation to high technology medicine. However, a combination of demographic, technological and social changes will necessitate a different emphasis in the future.     

Transplantation of septal cholinergic neurons to the hippocampus improves memory impairments of spatial learning in rats treated with AF64A

Embryonic septal neurons were transplanted into damaged hippocampus in adult rats which had received lateral ventricular administration of AF64A, a cholinergic neurotoxin. About 3 months after transplantation, the rats with bilateral septal grafts showed significant improvement in the radial maze and T-maze tasks. Many ingrowths of acetylcholinesterase (AChE)-positive fibers originating from the grafts were observed in the hippocampus of the rats which showed good performance in these learning tasks. These results indicate that transplantation of septal cholinergic neurons into the AF64A-treated hippocampus may induce at least partial recovery in learning tasks believed to involve the hippocampus.     

Long-term follow-up study of gastric adenoma/dysplasia

BACKGROUND AND STUDY AIMS: The natural course of gastric adenoma/dysplasia, regarded as a precancerous lesion, is still uncertain. PATIENTS AND METHODS: From 1976 to 2000, 48 lesions in 43 patients (37 men, six women; mean age 59 years) were diagnosed as having gastric adenoma/dysplasia based on their first biopsies. These lesions were followed for a median of 4.7 years (mean 6 years, range 3-18 years) to evaluate the risk of progression to invasive carcinoma. Retrospectively, histological diagnoses of the biopsy and resected specimens were reclassified according to the Vienna classification of gastrointestinal epithelial neoplasia, and macroscopic changes were evaluated. RESULTS: The diagnosis at first biopsy of the 48 lesions was low-grade adenoma/dysplasia (LGD; category 3) in 38 cases and high-grade adenoma/dysplasia (HGD; category 4) in 10 cases. Ninety-seven percent of the LGD (category 3) lesions (37 of 38) showed no histological changes during the follow-up period; the remaining lesion progressed to noninvasive carcinoma (category 4). Macroscopically, 84 % (32 of 38) of the LGD lesions (category 3) showed no remarkable changes in size, while 11 % (four of 38) shrank and 5 % (two of 38) grew larger. Nine of the 10 HGD lesions (category 4) remained histologically unchanged, while the other progressed to intramucosal carcinoma (category 5). Macroscopically, four of the 10 HGD lesions (category 4) (40 %) showed no remarkable changes in size, while the remaining six (60 %) grew larger. CONCLUSIONS: LGD lesions (category 3) have a quite low risk of progressing to HGD or noninvasive carcinoma (category 4), and were never observed to progress to invasive carcinoma (category 5). HGD lesions (category 4) occasionally progressed to intramucosal carcinoma (category 5), with no instance of invasion into the submucosa or beyond.     

Corticosteroids and surfactant change lung function and protein leaks in the lungs of ventilated premature rabbits.

Fetal rabbits were treated with corticosteroids by maternal administration for 48 h before delivery at 27 d gestational age. The treated and control rabbits were placed on ventilator-plethysmographs so that ventilation could be adjusted by regulation of tidal volumes to 10-13 ml/kg body wt. [125I]albumin was mixed with fetal lung fluid at birth, alternate rabbits from each litter were treated with Surfactant-TA, and [131I]albumin was injected intravascularly. The movement of the labeled albumins into and out of the alveolar wash and lung tissue was measured after 30 min of ventilation. Corticosteroid treatment (total dose, 0.2 mg/kg betamethasone) significantly decreased the protein leak across the endothelium (P less than 0.001) but increased the protein leak across the epithelium (P less than 0.001). Surfactant treatment decreased both the endothelial and epithelial leaks, and the combination of surfactant and corticosteroid treatments decreased endothelial leaks to 29% of control values and increased compliance more than either treatment alone. The 48-h corticosteroid treatment did not increase alveolar surfactant pool sizes. Corticosteroids significantly changed lung protein leaks independently of surfactant, and improved the response of the preterm lung to surfactant treatments.