Differential regional hemodynamic changes produced by L-glutamate stimulation of the locus coeruleus

The locus coeruleus (LC) exerts an inhibitory influence on the cardiovascular system. Microinjection of the excitatory amino acid, L-glutamate, into the LC elicits a decrease in arterial pressure as a result of a decrease in total peripheral resistance (TPR). The aim of the present study was to examine the role of the LC in the regulation of the regional hemodynamics. Employing anesthetized rats, the blood flow to the renal, mesenteric and hind-limb vascular beds was measured with an electromagnetic flowmeter. The changes in regional blood flow tnd vascular resistance evoked by chemical stimulation of the LC were examined separately in each region. During the depressor response elicited by LC stimulation, the hind-limb and renal vascular resistance was signfficantly decreased, while the mesenteric resistance was unchanged. The vasodilatation appeared to be more prominent in the hind-limb muscle than in the systemic circulation. Renal nerve denervation attenuated the decrease in renal vascular resistance elicited by LC stimulation. However, a small part of this response still remained in the denervated kidney. The present results suggest therefore that: (1) LC neurons exert differential hemodynamic effects on the hind-limb muscle, renal and mesenteric vascular beds; (2) the largest contribution to the decrease in TPR is related to vasodilatation in the hind-limb muscles; and (3) the renal vasodilatation elicited by LC stimulation is not mediated solely by the renal innervation.     

Ammonia metabolism during perinatal period--ontogenesis of enzymes in pyrimidine biosynthesis and urea cycle system

The enzymes and intermediate metabolite of pyrimidine biosynthesis and ammonia metabolism were studied during perinatal period in rats. The activity of carbamyl phosphate synthetase I(CPS I) in fetal rat liver was low up to the 19th day of gestation, but a rapid increase was observed on the 20th day of gestation. The activity of CPS I in adult liver was about three times as high as that on the 17th day of gestation in fetal rat liver. The activities of carbamyl phosphate synthetase II(CPS II) and aspartate transcarbamylase (ATC) in fetal rat liver were much higher than those in adult liver, but a rapid decrease was observed from the 17th day of gestation up to birth. The activities of CPS II and ATC in adult liver were about 5--10% of those on the 17th day of gestation. The change in orotate content during the perinatal period in fetal rat liver was parallel to changes in the activities of CPS I and ATC, and a rapid decrease in orotate content in the last gestational stage was related to a rapid decrease in CPS and ATC activities. These results indicate that the activities of CPS I and CPS II change from the end of the gestational stage up to birth, and the proposed metabolic regulation of fetal growth and developments of considerable interest.     

Asymmetric velocity and acceleration profiles of human arm movements

Summary Displacement, velocity, acceleration and jerk (change of acceleration with time) were analyzed for arm flexion movement over a wide range of movement amplitudes and speeds. Relative time to peak velocity or relative duration of acceleration, k, was approximately 0.5 for the movements with intermediate speed (about 0.5 s in movement time), i.e., symmetric velocity and acceleration profiles. For the slow and ballistic movements, k shifted towards values below and above 0.5, respectively creating asymmetric profiles. Consistent k-dependence of movement time, peak velocity, maximum acceleration and maximum deceleration were observed. Jerk cost, the square of the magnitude of jerk integrated over the entire movement, was calculated for each movement. A dynamic optimization technique to minimize jerk cost under the constraint on jerk input was applied to interpret the results, assuming that a major goal of skilled movements was to produce optimally smooth movements. The constrained minimum-jerk model explained speed dependent asymmetry of the velocity and acceleration profiles. Jerk cost consumed by the movements with intermediate speed approximately satisfied minimum-cost criterion predicted by the model but was higher than the criterion for slow and ballistic movements. The results suggested that optimality criteria other than jerk cost also should be considered to predict movement profiles over the entire range of speeds.     

Follow-up studies of children treated with a long-term intravenous nutrition (IVN) during the neonatal period

The outcome of the 28 children treated with intravenous nutrition (IVN) for more than 4 wk during the neonatal period was investigated. Ten of the 28 children had a normal length of small bowel (group 1) and the other 18 children had a short bowel (group 2). Eight of these 28 children (4 in group 1 and 4 in group 2) died during or after cessation of IVN; three died from complication of IVN and 5 died from their initial disease. On physical examination, delay in catch-up growth was observed in the early postoperative period, particularly in children in group 2, but this diminished with time. Mental and emotional development showed both groups to be within the normal range, except for two children. Intellectual function was also normal in five children over the age of 4 yr who were examined. Hepatic dysfunction was noticed during IVN in 30.0% in group 1 and 66.7% in group 2, indicating that the longer the duration of IVN, the higher the incidence of liver damage. Furthermore, histologic abnormalities in these neonates lasted for a longer time. These results imply that long-term IVN during the neonatal period in surgical patients does not interfere with physical and developmental growth. However, careful and long-term follow-up of liver function after IVN is necessary.     

Polymeric phospholipid analogues, 20. Synthesis and polymerization of 20-(methacryloyloxy)icosyl 2-(trimethylammonio)ethyl phosphate and 32-(methacryloyloxy)dotriacontyl 2-(trimethylammonio)ethyl phosphate

20-(Methacryloyloxy)icosyl 2-(trimethylammonio)ethyl phosphate ( 4a ) and 32-(methacryloyloxy)dotriacontyl 2-(trimethylammonio)ethyl phosphate ( 4b ) were prepared and characterized. These monomers were polymerized and the properties of the resultant polymers are described.     

Experimental study on stability of a high-porosity expanded polytetrafluoroethylene graft in dogs.

PURPOSE: The purpose of the present study was to evaluate the stability of a high-porosity expanded polytetrafluoroethylene (ePTFE) graft, which has been shown to possess excellent biocompatibility and tissue integration. METHODS: The graft used in the present study was a high-porosity ePTFE graft , which had an average internodal distance of approximately 60 microm and a random node architecture with tortuous path channels extending from the outer to the inner surface. Eleven beagle dogs (each group n = 3 or 4) weighing 10-12 kg were used. The graft, with a 6 mm inside diameter and a 30-40 mm length, was implanted into the canine abdominal aorta and retrieved after 2-80 weeks. The deformation of the graft was evaluated by conventional computed tomography (CT). The radial tensile strength, longitudinal tensile strength, and suture retention strength of the graft were measured after 2-80 weeks. RESULTS: CT studies showed no anastomotic aneurysm or deformation of the graft. Physical tests demonstrated no significant deterioration in suture retention strength, radial tensile strength or longitudinal tensile strength for periods ranging from 2-80 weeks compared to pre-implantation grafts. CONCLUSION: The graft possesses adequate stability that ensures safe and effective clinical use.     

Production of slow reacting substance in rat granulomatous inflammation

Production of slow reacting substance (SRS) in inflamed tissue was examined. Minced-pouch walls from carrageenin granulomas of 3, 7 and 14 days old in rats were incubated in the presence of cysteine and Ca²⁺-Ionophore. SRS-like substance was found to be formed during the incubation. Production of the substance was diminished by the presence of BW 755C, but enhanced by indomethacin in the reaction mixture. The substance was partially purified by XAD-8 and silicic acid column chromatographies and was shown to be SRS by its typical contractile activity on guinea-pig ileum selectively antagonized by FPL 55712. Production of SRS by the granuloma was highest on day 3, and then decreased. No detectable SRS activity was present in exudates of granuloma at any stage.     

Clinicopathologic features of encapsulated hepatocellular carcinoma: a study of 26 cases.

The clinicopathologic features of 26 cases of hepatocellular carcinoma (HCC) surrounded by a grossly distinct capsule-like fibrous tissue were studied. The frequency of this type was 10.3% among autopsy cases of HCC. The mean age of the patients was 64.1 years, which was significantly older compared with that of 143 cases of nonencapsulated HCC. Hepatitis-B surface antigen in serum was positive in 18.7% of the cases studied, the positivity rate being lower than that of HCC in general. Histologically, the tumor was relatively well differentiated and the capsule was the product of slow expanding growth. Intravenous tumor invasion was less frequent compared with other types of HCC. Clinically, celiac angiography proves to be a most useful diagnostic method; a thick capsule may be demonstrated as a thin radiolucent rim around the mass. The clinical course from the early stage is protracted and, if detected early, this type of HCC may be removed surgically.     

Juxtasellar mycotic abscess

A rare case of juxtasellar mycotic abscess with suprasellar extension is reported. The patient had double vision, only a mild abducens palsy, and no sign of inflammation, history of nasal sinusitis, or diabetes mellitus. Although a histologic examination showed massive fungal mycelia with thin capsules and no tumor cells, the neuroradiologic findings were like those in a clival chordoma or epidermoid tumor.