Vasoconstriction Induced by β-Adrenergic Antagonist in the Tail of Chronic Spinal Rats

Adult Wistar male rats were used for this experiment. Spinal cord was transected between the C_7 and Th_1 vertebrae under anesthetic condition. After the surgical operation, rats were reared in a warm room (30℃) as chronic spinal rats, and experiment was also performed in a climatic chamber (30℃, 60% r.h.). During the experiment, conscious spinal rats were placed in a small wire-mesh cage. Propranolol hydrochloride (Prop., 8mg/kg; β-adrenergic antagonist) was injected intraperitoneally. Rectal temperature (Tre), tail skin temperature (Ttail) and ambient temperature (Ta) were detected by thermistor probes and recorded simultaneously. In some cases, in addition to such parameters mentioned above, heart rate (HR) calculated by electrocardiogram (ECG) and arterial blood pressure (BP) through the femoral catheter were also recorded. As the index of the tail blood flow, the difference (dTtail) between Ttail and Ta was calculated (dTtail=Ttail-Ta). A sustained decrease in dTtail for 50 min was observed after the Prop. injection in Group-A (S<1W; less than 1 week (W) after the spinalization, N=6), Group-B (1W<S<2W, N=10) and Group-C (2W<S, N=6). In Group-A, mean dTtail was 1.5±0.3℃ before the injection and 0.8±0.3℃ (p<0.05) at 30 min after the injection, mean Tre was 36.3±0.2℃ before the injection and 36.2±0.2℃ (not significant) at 30 min after the injection. In Group-B, mean dTtail was 1.3±0.4℃ before the injection and 0.2±0.2℃ (p<0.01) at 30 min after the injection, mean Tre was 37.2±0.3℃ before the injection and 37.2±0.3℃ at 30 min after the injection. In Group-C, mean dTtail was 1.6±0.4℃ before the injection and 0.5±0.4℃ (p<0.05) at 30 min after the injection, mean Tre was 38.2±0.6℃ before the injection and 38.8±0.7℃ (p<0.05) at 30 min after the injection. By the Prop. injection HR decreased markedly and it stayed at the low level of about 300 beats/min. Mean HR was 394±25 beats/min before the injection, and 292±13 beats/min at 10 min, 285±13 beats/min at 20 min, 285±19 beats/min at 30 min (p<0.05). Arterial BP did not change or slightly increased from just after the injection. Mean value of BP was 82±6 mmHg before the injection, 82±8mmHg at 30 min after the injection. After intraperitoneal injection of the physiological solution, neither BP nor Tre changed. From these results it is assumed that decrease of dTtail after the Prop. injection in chronic spinal rats is due to the vasoconstriction in the tail but not due to the reduction in temperature of circulating blood. The possible explanations for this phenomenon were discussed, as follows; 1, an enhancement of α-adrenergic vasoconstrictor effect by β-adrenergic antagonist 2, the sympathetic reflex triggered by the hemodynamic changes after administration of β-adrenergic antagonist. However from these results, it is difficult to concluded decisively and to explain the underlying mechanisms of the phenomenon. It remains to be solved whether the vasoconstrictor nerves were involved in this response or not in chronic spinal rats

Effects of Chronic Heat or Cold Exposure on Growth and Blood Pressure in Rats

We studied the effects of various environmental temperatures on growth and blood pressure in rats. Spontaneously hypertensive rats (SHR) and their mother strain, normotensive Wistar-Kyoto rats (WKY) were used as the experimental animal. Rats of the two strains, SHR and WKY of 1 month old were divided into three groups randomly and they were housed in three rooms, of which temperatures were controlled at a constant, 30℃ (H-group), 22-24℃ (N-group) and 10℃ (C-group), respectively. Effects of environmental temperature on body weight gain were studied. Growth retardation was observed in the H-group of both strains. Maximal body weight gains were higher and reduced more quickly in SHR compared to those in WKY. In both SHR and WKY, at approximately 4 months old, the ratio of the tail to body surface areas was in the order of H-group>N-group>C-group in both strains. Systolic blood pressure (BP) was measured by the tail cuff method at approximately 4 months old. In WKY, BP in the C-group was significantly higher than that in H-group. In SHR, the BPs of the three groups were high compared to those in WKY groups, to which rats were exposed since 1 month old. And the BPs of C-group and H-group were significantly high compared to that in N-group. These facts indicate that effects of environmental temperature, to which rats were exposed since 1 month old, on growth were similar in WKY and SHR, and that the effects of the environmental temperature on systemic BP are clear in normotensive WKY, whereas in SHR, genetic expression of the hypertensive phenotype is consistent at various environmental temperatures

The effect of intraluminal pressure upon the frequency of intestinal contraction waves.

In guinea pigs the lumen of an excised jejunal segment was perfused to study the effect of intraluminal pressure on the frequency of rhythmic contraction waves. Within the range of 0 to 40 mmH2O, increases in intraluminal pressure caused increases in the frequency of contraction waves. At pressures of 10, 15, 20, 30 and 40 mmH2O the frequency was 7.9, 9.0, 10.9, 12.5 and 13.3 per min (mean of ten preparations), respectively. An exponential relationship was proved to exist between the pressure and the frequency.</p

Isotopic analysis of Ni, Cu, and Zn in freshwater for source identification

Nickel (Ni), copper (Cu), and zinc (Zn) are commonly used in human activities and pollute aquatic environments including rivers and oceans. Recently, Ni, Cu, and Zn isotope ratios have been measured to identify their sources and cycles in environments. We precisely determined the Ni, Cu, and Zn isotope ratios in rain, snow, and rime collected from Uji City and Mt. Kajigamori in Japan, and investigated the potential of isotopic ratios as tracers of anthropogenic materials. The isotope and elemental ratios suggested that road dust is the main source of Cu in most rain, snow, and rime samples and that some of the Cu may originate from fossil fuel combustion. Zinc in the rain, snow, and rime samples may be partially attributed to Zn in road dust. Zinc isotope ratios in the Uji rain samples are lower than those in the road dust, which would be emitted via high temperature processes. Nickel isotope ratios are correlated with V/Ni ratios in the rain, snow, and rime samples, suggesting that their main source is heavy oil combustion. Furthermore, we analyzed water samples from the Uji and Tawara Rivers and the Kakita River spring in Japan. Nickel and Cu isotope ratios in the river water samples were significantly heavier than those in rain, snow, and rime samples, while Zn isotope ratios were similar. This is attributed to isotopic fractionation of Cu and Ni between particulate-dissolved phases in river water or soil

Threshold Core Temperatures for Tail Vasodilation During General Warming in Spontaneously Hypertensive Rats (SHR) and Stroke-prone SHR (SHRSP)

In order to study heat dissipation ability of spontaneously hypertensive rats, threshold core temperatures for occurrence of the tail vasodilation were compared among adult male spontaneously hypertensive rats (SHR), stroke-prone SHR (SHRSP) and Wistar-Kyoto rats (WKY). Mean age of month (M.) and mean systolic blood pressure were 8.4±0.5 M; 205±5 mmHg for SHR, 7.2±0.6 M; 240±8 mmHg for SHRSP and 7.6±1.1 M; 140±6 mmHg for WKY. For the measurement, each rat was placed into a small wire-mesh cage for a loose restraint. Rectal temperature, tail skin temperature and air temperature were simultaneously recorded by means of thermistor probes or copper-constantan thermocouples. Air temperature was gradually raised at a constant rate of 0.17℃/min. Stepwise changes in the tail skin temperature were observed during the gradual elavation of the air temperature. The beginning of the tail vasodilation was detected by the 1st increase in tail skin temperature. Mean threshold core temperature for the 1st vasodilation in SHR, SHRSP and WKY were, 38.9±0.1℃, 38.4±0.1℃ and 38.0±0.1℃, respectively. Threshold core temperatures for the 1st vasodilation in SHR and SHRSP were significantly high compared to that in WKY, while the threshold in SHRSP was significantly lower than SHR. Mean values of threshold Ta for the 1st tail vasodilation in SHR, SHRSP and WKY were 30.1±0.5℃, 29.9±0･6℃ and 29.7±0.5℃, respectively. There was no statistical significance among these values. These results are consistent with the fact that the core temperature in adult SHRSP is not always high as SHR, even though blood pressure of SHRSP is higher than SHR. And these facts also suggest that high systemic blood pressure itself may not cause developing high core temperature in these genetically hypertensive rats

Promotion of rabbit ligament healing by local delivery of hepatocyte growth factor

Background: Extracapsular ligament injuries of the knee and ankle are common injuries. Ligaments heal slowly, usually over months or longer by scar formation rather than by tissue regeneration. This study was performed to evaluate the therapeutic effect of locally delivered recombinant hepatocyte growth factor (HGF) on the early healing of ligaments in a rabbit model. Methods: Japanese white rabbits were subjected to a standardized gap injury in the medial collateral ligaments (MCLs) of both knees. Each rabbit underwent bilateral transection of the midsubstance of the MCL, which was not repaired. During postoperative days 0-6, the rabbits were injected with 10 μg human recombinant HGF into the right MCL, while the left MCL was injected with saline alone. One, 3, 6, and 12 weeks after surgery, experimental rabbits were sacrificed. The structural properties of the femur-MCL-tibia complex were then assessed and the tissue was subjected to histological evaluation. To see the distribution of cells that express c-Met receptor, the tissue was subjected to immunohistochemistry. Results: Immunohistochemical evaluation revealed that c-Met expression was observed particularly at opposing ligament ends in the HGF-treated limbs 1 week after surgery. Histological evaluation revealed earlier neovascularization and more aligned collagen fibers in the MCLs of the HGF-treated group than the control group. In mechanical evaluations, similar ligament failure modes were noted in the two groups. After 3 weeks, HGF-treated limbs had significantly improved structural properties than the paired control limbs. Conclusions: Our findings indicate local administration of recombinant HGF promotes early steps in ligament healing and the repair of structural properties in a rabbit model. Local administration of HGF may represent a new therapeutic approach to accelerating healing and rehabilitation after ligament injury. © 2011 The Japanese Orthopaedic Association

Outcomes and failure factors in surgical treatment for osteochondritis dissecans of the capitellum

BACKGROUND: Osteochondritis dissecans (OCD) of the capitellum is an intra-articular lesion and one of the leading causes of permanent elbow disability. The treatment of advanced capitellar OCD remains challenging because of the limited potential of the articular cartilage for self-repair. The purpose of this study was to investigate the outcome of surgical treatment for OCD of the capitellum. METHODS: From 2000 to 2010, 32 male patients who had advanced lesions of capitellar OCD were treated operatively. The mean age of the patients was 14.4 years at the time of surgery. Twenty-nine patients played baseball and 3 played other sports. The lesions were of the centralized type in 9 patients, the lateral type in 4 patients, and the widespread type in 19 patients. For the surgical procedure, osteochondral peg fixation was selected for 13 patients and osteochondral autograft transplantation for 19 patients. Clinical outcome was measured with the elbow rating system including range of motion, and the number of patients who returned to active sports participation within 1 year after surgery was determined. RESULTS: The mean total arc of elbow motion increased from 123±17 degrees preoperatively to 132±14 degrees postoperatively. The mean clinical score improved significantly from 133±24 to 177±27. Within the first year after surgery, 81.3% of the patients returned to active sports playing. However, 4 of 8 patients (50%) in which osteochondral peg fixation was performed for lesions of the lateral widespread type required reoperation. CONCLUSIONS: Our results indicate that osteochondral peg fixation and osteochondral autograft transplantation may improve elbow rating score, and may facilitate a return to active sports participation. However, osteochondral peg fixation may be insufficient for lesions of the widespread type because of their poor stability. The large lateral condyle lesions had a worse outcome, and future studies will need to develop improved treatment for these defects. Copyright © 2013 by Lippincott Williams & Wilkins

Voxel-based structural magnetic resonance imaging (MRI) study of patients with early onset schizophrenia

<p>Abstract</p> <p>Background</p> <p>Investigation into the whole brain morphology of early onset schizophrenia (EOS) to date has been sparse. We studied the regional brain volumes in EOS patients, and the correlations between regional volume measures and symptom severity.</p> <p>Methods</p> <p>A total of 18 EOS patients (onset under 16 years) and 18 controls matched for age, gender, parental socioeconomic status, and height were examined. Voxel-based morphometric analysis using the Brain Analysis Morphological Mapping (BAMM) software package was employed to explore alterations of the regional grey (GM) and white matter (WM) volumes in EOS patients. Symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS).</p> <p>Results</p> <p>EOS patients had significantly reduced GM volume in the left parahippocampal, inferior frontal, and superior temporal gyri, compared with the controls. They also had less WM volume in the left posterior limb of the internal capsule and the left inferior longitudinal fasciculus. The positive symptom score of PANSS (higher values corresponding to more severe symptoms) was negatively related to GM volume in the bilateral posterior cingulate gyrus. The negative symptom score was positively correlated with GM volume in the right thalamus. As for the association with WM volume, the positive symptom score of PANSS was positively related to cerebellar WM (vermis region), and negatively correlated with WM in the brain stem (pons) and in the bilateral cerebellum (hemisphere region).</p> <p>Conclusion</p> <p>Our findings of regional volume alterations of GM and WM in EOS patients coincide with those of previous studies of adult onset schizophrenia patients. However, in brain regions that had no overall structural differences between EOS patients and controls (that is, the bilateral posterior cingulate gyrus, the right thalamus, the cerebellum, and the pons), within-subject analysis of EOS patients alone revealed that there were significant associations of the volume in these areas and the symptom severity. These findings suggest that at an early stage of the illness, especially for those with onset before brain maturation, a wide range of disturbed neural circuits, including these brain regions that show no apparent morphological changes, may contribute to the formation of the symptomatology.</p

Oblique coronal and oblique sagittal MRI for diagnosis of anterior cruciate ligament tears and evaluation of anterior cruciate ligament remnant tissue

Background: The purpose of this study was to investigate the efficacy of additional oblique magnetic resonance imaging (MRI) for the diagnosis of anterior cruciate ligament (ACL) tear and evaluation of ACL remnant tissue. Methods: We retrospectively reviewed the records of 54 knees. Three independent readers evaluated the MR images by the use of three methods: orthogonal sagittal images only (method A); orthogonal sagittal and additional oblique sagittal images (method B); and orthogonal sagittal and oblique coronal images (method C). The sensitivity, specificity, and accuracy for the diagnosis of an ACL tear and the detection of the condition of the ACL remnant tissue by the use of each method were calculated in comparison with arthroscopic findings as the reference standard. Results: The arthroscopic records revealed 27 knees with intact ACLs and 27 with torn ACLs. Among the 27 knees with torn ACLs, 9 did not have continuous remnant tissue and 18 had certain remnant tissue attached to the femur or the posterior cruciate ligament. The specificities and accuracies of methods B and C for diagnosing an ACL tear were higher than those for method A. The sensitivity, specificity, and accuracy of method C for the detection of ACL remnant tissue were higher than those for method A and B. Conclusions: Additional use of oblique MRI improved the accuracy of diagnosis of ACL tear and showed a reasonable level of efficacy in detecting ACL remnant tissue. Level of evidence: Level IV (case series). © 2013 Elsevier B.V