Interleukin-18-deficient mice exhibit diminished chronic inflammation and airway remodelling in ovalbumin-induced asthma model.

Interleukin (IL)-18, which is produced by activated monocytes/macrophages and airway epithelial cells, is suggested to contribute to the pathophysiology of asthma by modulating airway inflammation. However, the involvement of IL-18 on modulating chronic airway inflammation and airway remodelling, which are characterized in a refractory asthma model exposed to long-term antigen, has not been investigated sufficiently. We examined the role of IL-18 in chronic airway inflammation and airway remodelling by long-term antigen exposure. IL-18-deficient and C57BL/6-wild-type mice were sensitized by ovalbumin (OVA) and were then exposed to aerosolized OVA twice a week for 12 weeks. We assessed airway inflammation by assessing the infiltration of cells into the airspace and lung tissues, and airway remodelling by airway mucus expression, peribronchial fibrosis and smooth muscle thickness. In IL-18-deficient mice, when exposed to OVA, the total cells and neutrophils of the bronchoalveolar lavage fluid (BALF) were diminished, as were the number of infiltrated cells in the lung tissues. IL-18-deficient mice exposed to OVA after 12 weeks showed significantly decreased levels of interferon (IFN)-gamma, IL-13 and transforming growth factor (TGF)-beta1 in the BALF. The airway hyperresponsiveness to acetyl-beta-methacholine chloride was inhibited in IL-18-deficient mice in comparison with wild-type mice. In addition, IL-18-deficient mice exposed to OVA had fewer significant features of airway remodelling. These findings suggest that IL-18 may enhance chronic airway inflammation and airway remodelling through the production of IFN-gamma, IL-13 and TGF-beta1 in the OVA-induced asthma mouse model.

Physiological characteristics of diabetic neuropathy in sucrose-fed Otsuka Long-Evans Tokushima fatty rats.

Diabetic neuropathy is a very common complication of diabetes mellitus, and animal studies have contributed tremendously to its understanding. The aim of this study was to estimate the neuropathic alterations in the Otsuka Long-Evans Tokushima fatty (OLETF) rats, an animal model of human type 2 diabetes mellitus. For this purpose, four groups of animals were used: untreated OLETF rats, sucrose-fed for 2 months OLETF rats, untreated Long-Evans Tokushima Otsuka (LETO) nondiabetic rats as genetic controls of OLETF, and sucrose-fed LETO rats. All were examined at baseline, at the end of the sucrose treatment, and during a washout period. The following parameters were evaluated: motor nerve conduction velocity (MNCV), sensitivity to noxious thermal and mechanical stimuli using the tail-flick (TF) and tail-pressure (TP) tests, and blood glucose (BG) and HbA1c levels. Our results showed that BG and HbA1c were significantly higher in OLETF rats when compared with those in control LETO rats. Sucrose caused remarkable increase of BG and HbA1c in the OLETF rats, but not in the sucrose-fed LETO rats. MNCV and thermal nociception significantly decreased in OLETF rats in their 10th month, while the values of the TP test did not differ compared with those from LETO rats. Sucrose administration significantly decreased the MNCV, and increased the pain threshold evaluated by the TF and TP tests, compared with those in the control OLETF rats. The studied parameters were not significantly altered in sucrose-fed LETO rats. In conclusion, our findings show that signs of diabetic neuropathy appear late in the individual development of the OLETF rats, and MNCV and thermal nociception are selectively affected in this strain. Sucrose deteriorated the diabetic state, decreased MNCV, and caused thermal and mechanical hypoalgesia.

Comparative studies on the extractability of collagen from aortas of stroke-prone spontaneously hypertensive and normotensive rats.

The molecular states of collagen in the aortas of age-matched stroke-prone spontaneously hypertensive (SHRSP) and normotensive Wistar Kyoto rats (WKY) were studied by analyzing its extractability under defined conditions. The monomeric and oligomeric collagen extractable with 0.5 M acetic acid/6 M urea from aortic homogenates of 9-month-old SHRSP and WKY comprised approx. 0.6 and 2.0%, respectively, of the total collagen. On incubation of the acetic acid/urea-extracted residues with pepsin at 4 degrees C, the levels of the collagen alpha 1(I) and alpha 2(I) chains solubilized from the SHRSP residues were both less than 50% of those from the WKY residues. When the residues were incubated with pepsin at 15 or 25 degrees C, the differences became smaller. When the acetic acid/urea residues were hydrolyzed with cyanogen bromide, nearly identical peptide maps were obtained for SHRSP and WKY. The aortas from 2-month-old SHRSP and WKY contained much larger proportions of acid/urea-extractable collagen than those of the older rats (8.2 and 13% of the respective total collagen). The levels of the alpha 1(I) and alpha 2(I) chains solubilizable from the respective residues by pepsin at 4 degrees C were similar to each other. These results indicate that aortic collagen fibrils in SHRSP are stiffened more prominently than those in WKY.

Cadmium effect on the Na,K-ATPase system in cultured vascular smooth muscle cells.

The present study focuses on the interaction between cadmium (Cd) and the Na, K-ATPase system in in vitro grown vascular smooth muscle cells (VSMCs) derived from the rat carotid artery. In disrupted VSMCs rendered permeable by osmotic shock, Cd inhibited Na, K-ATPase; I50 was reached at 10(-5) M Cd. Mg-ATPase was also inhibited by Cd; I50 was attained at concentrations of 10(-4) M Cd. Cd inhibition of Na,K-ATPase in the VSMCs was noncompetitive with respect to Na, K, and ATP. Rubidium transport experiments performed with intact VSMCs demonstrated that within an incubation period of 150 minutes, a concentration of 10(-4) M Cd in the extracellular fluid exerted no acute effect on the Na-K pump. Within this time interval, intracellular Cd attained a concentration eightfold higher than the extracellular Cd concentration. Thus, it appears that under acute conditions Cd exerts its inhibitory effect on Na, K-ATPase only in disrupted VSMCs. The data further suggest that, in the VSMC, conditions under which Cd inhibits Na, K-ATPase are consistent with inhibition from the cytoplasmic side of the cell membrane.

An autopsy case of I-cell disease. Ultrastructural and biochemical analyses.

An autopsy case of I-cell disease in a 4-year-old Japanese girl is presented. In this report, the authors analyze the relationship between morphologic (including electron microscopic) and biochemical findings. Lymph node, spleen, and kidney, which were stained with Hale's colloidal iron method, contained large amounts of hexosamine. These substances had accumulated in lymphocytes of B-cell lineage.

Glycation decreases the stability of the triple-helical strands of fibrous collagen against proteolytic degradation by pepsin in a specific temperature range.

When fibrous collagen of rat tail tendons was glycated by incubation with ribose, it became highly insoluble in dilute acetic acid and resistant to pepsin digestion at 5 degrees C, since it was cross-linked by advanced glycation end products. Extensively glycated fibrous collagen was found to be much less stable than non-glycated control fibrous collagen against pepsin digestion at 30 degrees C. Under conditions where nearly all of the glycated fibrous collagen was degraded into small peptides by pepsin, approximately 45% of the control collagen was left as large polypeptides having nearly the whole length of its triple-helical region. A soluble collagen, which consisted primarily of the triple-helical region of monomeric collagen, was found to be glycated as efficiently as the fibrous collagen on incubation with ribose at 30 degrees C, while the rate of cross-linking of the soluble collagen was very low, suggesting that the triple-helical strands do not undergo intramolecular cross-linking and that most of the cross-links produced in the glycated fibrous collagen are intermolecular ones. The glycated soluble collagen was as stable as the control collagen against pepsin digestion at 30 degrees C. These results indicate that the triple-helical strands of glycated fibrous collagen are much less stable than those of the non-glycated form against proteolytic digestion by pepsin at a temperature close to but below their melting point. Sugar-derived intermolecular cross-links are supposed to underly the decreased stability of the triple-helical strands.

The mechanism of interaction of sodium dodecyl sulfate with elastic fibers.

Sodium dodecyl sulfate (SDS), an anionic hydrophobic ligand, is known to alter the mechanical properties of elastic fibers. In order to analyze the mechanism of the alteration, two forms of fibrous elastins, "solid" and "powder" elastins, which consisted of fascicular elastic fibers and single or oligomeric elastic fibers, respectively, were prepared from bovine aorta, and the interactions of SDS with these elastins in the presence and absence of 0.15 M NaCl were studied. The solid elastin was able to retain 1.2- to 1.4-fold larger amounts of SDS than the powder elastin under both conditions, and both elastins retained 1.2-fold or larger amounts of SDS in the presence of NaCl than in its absence. Whereas both elastins released the retained SDS gradually on repeated washing with an SDS-free buffer, the release rates from the solid elastin, especially the rate in the presence of NaCl, were much smaller than those from the powder elastin, and the solid elastin retained approximately 40% of the bound SDS under conditions where the powder elastin lost most of its SDS. The SDS-binding capacities of both elastins were significantly lower than those of soluble kappa-elastin and serum albumin, which bound SDS homogeneously on the polypeptide chains. When the washed SDS-bound solid elastin was incubated with methylene blue and examined under a microscope, most of the methylene blue-SDS complex was located at the interfiber spaces of the elastic fibers. These results suggest that SDS alters the mechanical properties of elastic fibers by binding to the interfiber spaces and surfaces of the fibers rather than by binding to the internal polypeptide chains.

Increased intracellular calcium and altered phorbol dibutyrate binding to intact platelets in young subjects with insulin-dependent and non-insulin-dependent diabetes mellitus.

Intracellular calcium ([Ca2+]i) and phorbol ester binding were studied in intact platelets of young patients with insulin-dependent (IDDM) and non-insulin-dependent (NIDDM) diabetes mellitus. Our objective was to evaluate disturbances in calcium regulation and signal transduction in platelets of diabetics. [Ca2+]i in platelets of the IDDM group (135 +/- 20 nmol/L) under basal conditions was significantly higher than that of the control group (81 +/- 8 nmol/L, P = .019), whereas at 60 seconds after stimulation with 0.1 National Institutes of Health (NIH) U/mL thrombin, [Ca2+]i in the NIDDM group (484 +/- 36 nmol/L) was significantly higher than that of the controls (347 +/- 22 nmol/L, P = .003) and IDDM group (360 +/- 45 nmol/L, P = .04), respectively. Phorbol 12,13-dibutyrate (PdBu) maximal binding capacity (Bmax) in the IDDM group was significantly lower than that in the control group either under basal conditions or after stimulation with thrombin (P = .0034 and P = .015, respectively). Bmax in the NIDDM group was significantly lower than that in the controls only after stimulation with thrombin (P = .047). The Kd for PdBu of the IDDM group was lower than that of the control group under basal conditions (P = .017). When analyzing the pooled data of all subjects, a significant correlation was observed between Bmax and Kd (under basal conditions, r = .544, P < .0001; after stimulation, r = .601, P < .0001). Our results support the idea that the increased affinity for PdBu may compensate for the decreased binding capacity. We interpret the data as indicating that the change in the binding of phorbol ester to protein kinase C (PKC) units may result in an altered PKC/calcium interaction in the pathogenesis of diabetes mellitus. Our study indicates that such metabolic derangements of [Ca2+]i have already been developing in young diabetic patients.

Validity of microsphere model in cerebral blood flow measurement using N-isopropyl-p-(I-123) iodoamphetamine.

A microsphere model is sometimes used when calculating cerebral blood flow (CBF) using N-isopropyl-p-[I-123]iodoamphetamine (IMP), and is based on the assumption that there is essentially no washout of IMP. The validity of a microsphere model was investigated by comparison with the values of CBF obtained by means of a model which takes into consideration the diffusion of IMP from brain tissue to blood (nonmicrosphere model). When calculating CBF by the latter model, the look-up table method was used with expression of the double integral in the model equation by the recursion relations, a method which is useful for obtaining pixel-by-pixel values. The average rate constants for diffusion from brain to blood of gray and white matter were 0.021 and 0.0016 min-1, respectively. The values of CBF obtained by applying a microsphere model to the data acquired from 0 to 3.2 min after IMP injection were overestimated by approximately 23% compared with those values obtained using a nonmicrosphere model. This is considered to be due to the effect of the IMP activity in the vascular space. Values obtained using the data acquired from 3.2 to 6.4 min were underestimated by approximately 15%. When the values of CBF obtained by a microsphere model were interpolated, they became nearly equal to those obtained using a nonmicrosphere model at about 4 to 5 min after injection. This is suggested to be the reason why the underestimation due to diffusion from brain to blood is cancelled out by the overestimation due to the IMP in the vascular space. Our preliminary results suggest that it is necessary to take the diffusion of IMP from brain tissue to blood into account for the quantification of CBF using IMP.

Reactivity of intrarenal arteries to vasoconstrictor and vasorelaxant polypeptides in adult stroke-prone spontaneously hypertensive rats.

The reactivity of intrarenal arteries to vasoconstrictor and vasodilator polypeptides was examined in adult stroke-prone spontaneously hypertensive rats (SHRSP). The contraction response to endothelin-1 (ET-1) was greater in SHRSP than in age-matched Wistar-Kyoto rats (WKY), and so was the pD2 estimate (8.05+/-0.03 in SHRSP, and 7.73+/-0.06 in WKY; n=5, P < 0.05). The contraction response to, and the pD2 estimate of, vasopressin were comparable in SHRSP and WKY. Neuropeptide Y did not contract the intrarenal arteries. In norepinephrine-precontracted arteries with intact endothelium, substance P and neurokinin A did not relax the arteries of either SHRSP or WKY, while calcitonin gene-related peptide (CGRP) induced a profound relaxation response. Relaxation response to CGRP was significantly greater in SHRSP than in WKY. Atrial, brain, and C-type natriuretic peptides (ANP, BNP, CNP), vasoactive intestinal polypeptide (VIP), and peptide histidine isoleucine (PHI) all caused relaxation responses, with a greater extent of relaxation to ANP, BNP, and VIP and a less extent to CNP and PHI. However, there were no significant differences in these relaxation responses between SHRSP and WKY. The current results revealed the character of heterogeneity of rat intrarenal arteries in response to vasoconstrictor and vasodilator peptides, and showed an enhanced reactivity to ET-1 and to CGRP in SHRSP.

Optimum branched-chain amino acids concentration for improving protein catabolism in severely stressed rats.

In this study, an experiment was performed to investigate the optimal concentration of branched chain amino acid (BCAA) in hyperalimentation to be administered when protein catabolism is accelerated by sepsis or bodily injury. Amino acid solutions containing BCAA 25%, 30%, 40%, 45% and 50% were prepared and were administered iv for three days with other essential amino acid-containing nitrogen in the same volume into rats with peritonitis which had been developed by ligature and puncture at the cecum, and the results were compared. After observing for three days, the influence over nitrogen balance, improvement of 3-methyl-histidine/creatinine in urine, weight loss in muscles, and aminogram in serum and muscles indicated that the hyperalimentation under stress is utilized most effectively when amino acid contains 45% of branched-chain amino acid.

Endotoxin clearance through whole body rinse out in relation to histologic integrity in the rat.

The effects of normothermic whole body rinse out (NWBRO) with FC-43 perfluorocarbon emulsion on the course of endotoxic shock were examined in male Wistar rats. These animals, conscious and unrestrained, were infused over 10 min with 60 mg/kg of E. coli endotoxin (LD100) and observed for 6 hr. The rats developed hypotension, plasma extravasation, metabolic acidosis, increase in serum GPT and GOT, and extensive hemorrhages in the small intestine. Another group of rats was subjected to blood substitution with FC-43 emulsion (artificial blood) 30 min after endotoxin infusion, until the hematocrit dropped to less than 3%, after which 6-9 ml of donor blood was exchange transfused with the emulsion. NWBRO caused a transitory rise in the GOT level, but more importantly it resulted in 98% endotoxin clearance, improved blood alkaline reserves, trimmed elevated GPT and GOT levels, and attenuated hemorrhage and epithelial necrosis in the small intestine.

Quantitative analysis of myocardial ischemia by technetium-99m sestamibi exercise scintigraphy: a new method for change rate mapping.

In order to quantitatively assess the extent and severity of myocardial ischemia by Tc-99m sestamibi exercise myocardial scintigraphy, we developed a new method of change rate (CR) mapping and examined its efficiency. CR was calculated to divide the counts per pixel in the stress polar map by that in the rest polar map at each corresponding pixel. The CR map showed the CR values at each pixel. To correct the differences between the stress and rest images for the dose of Tc-99m sestamibi administered, the mean counts per pixel in the stress polar map and the rest map were adjusted to the same level. Regarding the regions in which the CR value was less than 1 as ischemia, we compared the abilities of the CR map and the polar map to detect coronary artery stenosis in 5 patients with angina pectoris. The sensitivity for coronary artery stenosis was 80% in the CR map, and 40% in the polar map. The specificity for both was 75%. We concluded that the CR map was effective in assessing the extent and severity of myocardial ischemia in Tc-99m sestamibi exercise myocardial scintigraphy.

Receiver operating characteristic (ROC) analysis of images reconstructed with iterative expectation maximization algorithms.

PURPOSE: The quality of images reconstructed by means of the maximum likelihood-expectation maximization (ML-EM) and ordered subset (OS)-EM algorithms, was examined with parameters such as the number of iterations and subsets, then compared with the quality of images reconstructed by the filtered back projection method. METHODS: Phantoms showing signals inside signals, which mimicked single-photon emission computed tomography (SPECT) images of cerebral blood flow and myocardial perfusion, and phantoms showing signals around the signals obtained by SPECT of bone and tumor were used for experiments. To determine signals for recognition, SPECT images in which the signals could be appropriately recognized with a combination of fewer iterations and subsets of different sizes and densities were evaluated by receiver operating characteristic (ROC) analysis. The results of ROC analysis were applied to myocardial phantom experiments and scintigraphy of myocardial perfusion. RESULTS: Taking the image processing time into consideration, good SPECT images were obtained by OS-EM at iteration No. 10 and subset 5. CONCLULSION: This study will be helpful for selection of parameters such as the number of iterations and subsets when using the ML-EM or OS-EM algorithms.

Twenty-four-hour Tl-201 delayed scan underestimates myocardial viability in patients with acute myocardial infarction after percutaneous transluminal coronary angioplasty.

BACKGROUND: Myocardial viability in area at risk of acute myocardial infarction (AMI) after reperfusion therapy may be underestimated by the 24-hour images due to reverse redistribution (r-RD). METHODS: Subjects were 37 AMI patients in whom Tc-99m pyrophosphate (PYP)/Tl-201 dual-isotope SPECT was positive. The 24-hour delayed scan was performed with only a Tl window. One month later, follow up rest Tl SPECT was performed to evaluate myocardial viability. In early (at PYP/Tl-201 dual-isotope SPECT), 24-hour, and one month follow up Tl studies, Tl uptake in the area of AMI was scored into four grades: 3 as normal to 0 as severely reduced. The scores were evaluated. RESULTS: Among the 37 AMI lesions, there were 16 r-RD, 3 RD, 16 fixed defect (FD) and 2 normal (positive PYP and normal Tl). Mean Tl scores were early; 1.4 +/- 1.1, 24-hr; 0.9 +/- 0.9 and one month; 1.3 +/- 1.1. The 24-hour Tl score was lower than the early and one month Tl scores (p < 0.01). CONCLUSION: Reverse redistribution is frequently observed in an area at risk where PYP SPECT was positive. Nuclear medicine physicians should be aware of the existence of frequent r-RD in Tl scan to avoid the underestimation of myocardial viability in the acute phase after PTCA.

Congenital absence of lacrimal puncta and of all major salivary glands: case report and literature review.

A 7-year-old girl had dry mouth and recurrent infections of the lacrimal fistulae with decreased lacrimal secretion. All four puncta were absent, and a Schirmer test showed decreased lacrimal secretion. Salivary gland imaging with sodium pertechnetate 99mTcO4 showed absence of all major salivary glands. Lower lip biopsy disclosed normal structure of the salivary gland. No evidence of abnormal inheritance patterns could be demonstrated.

Miller Fisher syndrome: etiological significance of serial blink reflexes and MRI study.

We studied a patient with Miller Fisher syndrome using a serial MRI and electrophysiological procedures. There were peripheral nerve pathology and CNS dysfunction. In particular, MRI showed a lesion at the level of the 3rd nerve nucleus.

Can magnesium act as a second messenger? Current data on translocation induced by various biologically active substances.

Free intracellular Mg2+([Mg2+]i) can potentially integrate the signals from hormones, cellular metabolism and organismal ion homeostasis and affect the activities of ion channel and other effectors. Interest in [Mg2+]i has been heightened by recent reports that small changes in [Mg2+]i in the physiological range can significantly modulate important cellular functions. In addition, a variety of new evidence shows that [Mg2+]i instantaneously changes following stimulation with various biologically active substances. These observations suggest that [Mg2+]i may act as a second messenger.

Inhibition of renal sympathetic nerve activity of anesthetized rats by intracerebroventricular administration of angiotensin II.

Effects of intracerebroventricular (i. c. v.) administration of angiotensin II (AII) on renal sympathetic nerve activity (RSNA), arterial pressure, and heart rate were examined in rats anesthetized with a mixture of urethane and alpha-chloralose. Administration of AII evoked an increase in arterial pressure and a decrease in RSNA with no significant change in heart rate. Prior i. c. v. administration of an AII antagonist, saralasin, greatly attenuated the pressor response and inhibition of RSNA induced by i. c. v. AII. Rats with sinoaortic denervation showed the same magnitude pressor response and decrease in RSNA as intact animals. The result suggests that central AII directly inhibits RSNA via AII specific receptors.

[Ocular manifestations in a case of infantile cystinosis].

A case of infantile cystinosis was reported. The diagnosis of cystinosis was made by the renal Fanconi syndrome and the ocular findings. The patient showed typical corneal and fundus changes associated with cystinosis. Corneal crystals and fundus pigmentary change were found early in life. The deposition of corneal crystals increased in the course of the disease, especially in the nasal and the temporal sides close to the limbus. By specular microscopy, the corneal crystals were needle-shaped and were larger and more numerous in the superficial layer of the stroma. The same shape of crystals ere found in the corneal endothelium, and the size of endothelial cells was markedly increased. There were also small crystals on the surface of the iris. The entire fundus showed a mottled appearance characterized by mixture of fine granular pigmentation and depigmentation associated with patchy depigmentation in the periphery. On the anterior surface of the retina, a glistening crystal appeared. As the crystal deposition in ocular tissues increases, even after successful peritoneal dialysis, eventual impairment of visual function may be expected.