Re-evaluation of normal human urinary proteins fractionated by one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis

Proteins in normal human urine were clearly fractionated into 26 bands with molecular weights from 14,000 to 230,000 by means of one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) coupled with silver staining. The main band contained uromucoid, and the second main band had albumin. However, when urine samples from healthy persons were electrophoresed in the absence of SDS using polyacrylamide gel or agarose gel, or a cellulose acetate membrane, albumin but not uromucoid, frequently formed the main protein band. It is suggested that this is due to the complexing of uromucoid subunits to form a large molecule which cannot penetrate into the gel. In order to correctly fractionate all the proteins contained in normal human urine, it was concluded that it was best to treat a urine sample with SDS with pre-condensation, fractionate it by SDS-PAGE and stain fractionated proteins by a highly sensitive method such as silver staining.     

Ascending contraction and descending relaxation in the distal colon of mice lacking interstitial cells of Cajal.

Recently an essential role of interstitial cells of Cajal (ICC) within myenteric plexus (ICC-MY) was suggested in ascending contraction and descending relaxation in the mouse ileum. The role of ICC in these neural reflexes was examined in the distal colonic segments prepared from the wild type and c-kit mutant, W/W(V) mice, in the present study. Localized distension of the segments from the wild type mice by using a small balloon resulted in ascending contraction and descending relaxation. In the segments from the mutant mice, localized distension also induced these neural reflexes similar to those observed in the wild type mice. Immunohistochemical examination demonstrated that ICC-MY and ICC present in muscle layers (ICC-IM) were severely disrupted in the mutant mouse, but only ICC, present within submucosal plexus (ICC-SMP), remained unchanged. In the small strips with ICC-SMP absent prepared from the mutant mouse, electrical field stimulation induced contraction or relaxation in the absence or presence of atropine, respectively. It was suggested that ICC have no important role in the ascending and descending neural reflexes in the mouse distal colon, this is in direct contrast to the role of ICC-MY in the ileum.     

Resetting of the arterial baroreflex increases orthostatic sympathetic activation and prevents postural hypotension in rabbits

Since humans are under ceaseless orthostatic stress, the mechanism to maintain arterial pressure (AP) under orthostatic stress against gravitational fluid shift is of great importance. We hypothesized that (1) orthostatic stress resets the arterial baroreflex control of sympathetic nerve activity (SNA) to a higher SNA, and (2) resetting of the arterial baroreflex contributes to preventing postural hypotension. Renal SNA and AP were recorded in eight anaesthetized, vagotomized and aortic-denervated rabbits. Isolated intracarotid sinus pressure (CSP) was increased stepwise from 40 to 160 mmHg with increments of 20 mmHg (60 s for each CSP level) while the animal was placed supine and at 60 deg upright tilt. Upright tilt shifted the CSP–SNA relationship (the baroreflex neural arc) to a higher SNA, shifted the SNA–AP relationship (the baroreflex peripheral arc) to a lower AP, and consequently moved the operating point to marked high SNA while maintaining AP. A simulation study suggests that resetting in the neural arc would double the orthostatic activation of SNA and increase the operating AP in upright tilt by 10 mmHg, compared with the absence of resetting. In addition, upright tilt did not change the CSP–AP relationship (the baroreflex total arc). A simulation study suggests that although a downward shift of the peripheral arc could shift the total arc downward, resetting in the neural arc would compensate this fall and prevent the total arc from shifting downward to a lower AP. In conclusion, upright tilt increases SNA by resetting the baroreflex neural arc. This resetting may compensate for the reduced pressor responses to SNA in the peripheral cardiovascular system and contribute to preventing postural hypotension.     

Vasodilator effects of sarafotoxins and endothelin-1 in spontaneously hypertensive rats and rat isolated perfused mesentery

Sarafotoxins (SRTa, SRTb and SRTc) and ET-1 produced a potent vasodilator effect in spontaneously hypertensive rats in vivo and in rat isolated perfused mesenteries in vitro. Among these peptides SRTc demonstrated the most potent vasodilator activity, and was three times more active than SRTa in both preparations. These peptides induced endothelium-dependent vasodilatation in vitro and pretreatment with methylene blue inhibited this effect, while exposure to the antagonists of other vasodilators did not. In contrast, [nitrophenylsulfenylated Trp21]SRTc, SRTc(1-18) and reduced and S-carboxymethylated SRTc caused no vasodilatation in either animal model; the vasodilator effect of acetylated SRTc was less potent than that of SRTc. These results suggest that (i) the vasodilatations of these peptides may be exerted through the release of endothelium derived relaxing factor; (ii) the C-terminal Trp21 and disulfide bonds are essential; and (iii) the N-terminal amino group plays an important role in vasodilator activity.     

Vasoconstrictor response of large cerebral arteries of cats to endothelin, an endothelium-derived vasoactive peptide

Endothelin, a 21-amino acid peptide produced by vascular endothelial cells, caused a sustained constriction of isolated large cerebral arteries of cats in a dose-dependent manner. The increased tone of the tissue did not return to the resting level after repeated washings. No vasodilator response was evoked by endothelin in the presence of an active tone. The contractile response of cerebral arteries was not inhibited by rubbing of the endothelium, cold storage denervation or indomethacin. In contrast, nicardipine or diltiazem antagonized the endothelin-induced contraction non-competitively. No contraction was evoked by endothelin in a Ca2+-free solution while the addition of Ca2+ ions in the presence of endothelin in a Ca2+-free solution caused a sustained contraction. Ca2+-induced contraction in the Ca2+-free solution containing endothelin was also inhibited by nicardipine. Therefore, endothelin causes a direct contraction of the smooth muscles of cat cerebral arteries, probably by activating the influx of Ca2+ ions through L-type Ca2+ channels of smooth muscles.     

Resolution of homonymous visual field loss documented with functional magnetic resonance and diffusion tensor imaging.

A 68-year-old man developed right homonymous hemianopic paracentral scotomas from acute infarction of the left extrastriate area. He was studied over the ensuing 12 months with visual fields, conventional MRI, functional MRI (fMRI), and diffusion tensor imaging (DTI). As the visual field defect became smaller, fMRI demonstrated progressively larger areas of cortical activation. DTI initially showed that the lesioned posterior optic radiations were completely interrupted. This interruption lessened in time and had disappeared by one year after onset. fMRI and DTI are innovative measures to follow functional and structural recovery in the central nervous system. This is the first reported application of these imaging techniques to acute cerebral visual field disorders.     

Ubiquitous Presence in Mammalian Cells of Enzymatic Activity Specifically Cleaving 8-Hydroxyguanine-containing DNA

Here we report the finding of enzymatic activity that specifically cleaves DNA containing 8-hydroxyguanine (oh⁸Gua) residues in various mammalian cells. To detect this activity, we used a synthetic double-stranded DNA containing a single oh⁸Gua at a defined position as the substrate, and analyzed the products of enzymatic digestion by polyacrylamide gel electrophoresis. Two cleavage sites near the oh⁸Gua residue were detected with partially purified fractions from cow brain and rat liver, and also with preparations from all mammalian tissues examined. These results suggest that enzymatic activity for the removal of oh⁸Gua from DNA is widely distributed in mammalian cells.     

Species differences in platelet aggregation induced by platelet-activating factor (PAF).

Species differences in platelet aggregation induced by platelet-activating factor (PAF) were investigated by using the same procedure of platelet preparation and biological assay. Washed platelets of six different species (horses, dogs, rats, rabbits, sheep and guinea pigs) were prepared employing the same method and platelet aggregation was induced by C16-PAF. Horse platelets were most sensitive to PAF (8.0 x 10(-12) M) and rabbit platelets activated by 5.0 x 10(-11) M PAF were also sensitive enough to detect PAF in clinical samples.     

Intercostal hemangioma

This paper presents a case of intercostal hemangioma, in which a complete surgical resection was accomplished based upon a tentative diagnosis provided by magnetic resonance imaging (MRI). A 27-year-old man visited our hospital for the evaluation of chest pain and shortness of breath after exertion. Computed tomography showed a soft tissue mass, 5.5×3.5 cm in size, arising from the right lateral 7th intercostal space. Dynamic MRI showed that the mass was enhanced rapidly in the early phase and that this early enhancement was maintained during the delayed phase, which was compatible with a diagnosis of intercostal hemangioma. The patient underwent surgery, and a complete resection of the tumor with the right 7th and 8th ribs and their intercostal muscles was accomplished. Histopathological examination confirmed the diagnosis of intramuscular hemangioma of the large-vessel type. Presently, 6 months after the operation, the patient is doing well, without any evidence of local recurrence.