Pseudorandom testing technique for the characterization of local hemodynamic control

Summary In order to investigate the low frequency properties of renal and femoral hemodynamic variables, pseudorandom testing techniques were used. The arterial flow of each bed, in separate experiments, was modulated by a low amplitude signal based on a pseudorandom binary sequence (PRBS) generated by digital computer.The cross-correlation functions between input flow and arterial pressure, venous pressure, and venous flow exhibit damped oscillations in all cases. These responses are parameterized in terms of a damping ratio () and an undamped natural frequency _n for a second order model. The parameters of the model are dependent upon the state of the bed as defined by mean arterial and venous pressures, mean flow through the bed, resistance, and oxygen consumption.The results of this study offer further insight into the dynamic low frequency autoregulation phenomenon for the renal and femoral beds of the dog.Supported by NIH Grant HE 11747.     

Voxel-based morphometry of human brain with age and cerebrovascular risk factors

The objectives of this study were to evaluate the correlations of the volumes of the gray matter and white matter with age, and the correlations of the tissue probabilities of the gray matter and white matter with age and several cerebrovascular risk factors. We obtained magnetic resonance (MR) images of the brain and clinical information from 769 normal Japanese subjects. We processed the MR images automatically by correcting for inter-individual differences in brain size and shape, and by segmenting the MR images into the gray matter and white matter. Volumetry of the brain revealed a significant negative correlation between the gray matter volume and age, which was not observed between white matter volume and age. Voxel-based morphometry showed that age, systolic blood pressure, and alcohol drinking correlated with the regional tissue probabilities of the gray matter and white matter.     

Two cases of limited cutaneous nodular amyloidosis with primary Sj?gren's syndrome]

We described two female patients with primary Sj?gren's syndrome associated with localized cutaneous nodular amyloidosis (LCNA), in which amyloid protein was derived from immunoglobulin light chain. Case 1; a 70-year-old female had complained with polyarthralgia, low-grade fever and parotid gland swelling. She was diagnosed as primary Sj?gren's syndrome. Three years later she noticed brown color small tumor on the thigh and yellow to brown nodules on the bilateral calves of legs. Skin biopsy from the left thigh revealed amyloid L protein deposition, which was positive for anti-lambda light chain staining, in almost entire dermis. Infiltration of lymphocytes and plasma cells around the amyloid deposit were prominent. Case 2; a 51-year-old female had noticed increasing eruption on the hip. Skin biopsy revealed amyloid L protein deposition in the dermis, which was negative for anti-lambda nor kappa light chain staining. When she was refereed to our hospital, she complained of xerostomia and xerophthalmia. She was diagnosed as primary Sj?gren's syndrome. In both cases, histological examination of a minor salivary gland biopsy revealed infiltration of lymphocytes and plasma cells but not amyloid deposit. Serum M protein and urine Bence-Jones protein were not detected. These cases represent localized amyloidosis without systemic involvement. It is widely recognized that Sj?gren's syndrome is frequently accompanied by B cell lymphoproliferative disorders. In LCNA, infiltration of plasma cells around the amyloid deposits was frequently prominent. The relation between these two disorders is discussed.     

Current status and problems of platelet function tests]

Platelet function tests have been utilized for a long time as a useful tool for the diagnosis of qualitative platelet disorders. However, recently reports suggest that platelet function tests currently available in routine laboratory do not necessarily reflect in vivo hemostatic states. First of all, bleeding time could sometimes be non-informative for the following reasons; 1) Duke method, the most popular method in Japan, has poor reproducibility, 2) there is no appropriate method for monitoring of aspirin ingestion, 3) prolongation of bleeding time does not correlate with the amount of blood loss during surgery. Platelet adhesion is still measured by the ability of platelets to be retained on glass beads. However, this test is unable to detect selectively platelet adhesion. Thus, the test in which platelets can exclusively adhere to subendothelial components such as collagen, may be required. Platelet aggregation has been mostly analyzed by the changes in light transmittance in platelet rich plasma (PRP) with a platelet aggregometer. However, this test totally depends on the platelet count in PRP or duration of time after taking blood from patients. Moreover, platelet aggregation in this system is optimally observed and is hardly detectable when the in vivo Ca++ concentration has been chelated. Furthermore, the test could not detect small platelet aggregates, thus being unable to measure the early phase of platelet aggregation. These observations suggest that more simple and specific tests should be developed and become available in routine laboratory.     

Central sites involved in lateral hypothalamus conditioned neural responses to acoustic cues in the rat

1. Unit activity in the lateral hypothalamus (LHA) of the rat was recorded during discrimination learning of cue-tone stimuli (CTS) predicting glucose (CTS1+) or intracranial self-stimulation (ICSS) (CTS2+) as positive reinforcement or electric shock (CTS1-) or tail pinch (CTS2-) as negative reinforcement. The same action, licking, was used as the behavioral response to all stimuli. Procaine hydrochloride, a local anesthetic, was microinjected into the ventral tegmental area (VTA) and the amygdala (AM). LHA neuron responses and licking were analyzed to investigate the afferent input pathway(s) responsible for LHA neural responses to conditioning CTSs in positive reinforcement and to identify the central site involved in CTS learning. Although the animals were restrained, there was no respiratory, cardiac rate, or blood pressure evidence of stress. The headholder was specially designed in our laboratory to avoid pain or discomfort to the animal. The subjects would often, after the first few sessions, voluntarily enter into position in the apparatus, presumably to obtain the reward available during the experiments. 2. In positive reinforcement, a rat was rewarded by 5 microliters of glucose or ICSS when it licked a spout. The rat licked for glucose after CTS1+ or for ICSS after CTS2+. In negative reinforcement, an aversive stimulus, either electric shock or tail pinch, was applied if the rat did not lick the spout. The electric shock and tail pinch were maintained weak enough to produce an avoidance ratio less than 20-30%, averaged in all trials. The rat licked to avoid electric shock after CTS1- or tail pinch after CTS2-. 3. Of 271 LHA neurons analyzed, 202 (74.5%) responded to either or both rewarding and aversive stimuli. The number of neurons that responded to only rewarding stimuli was relatively large (105/271), and the number that responded similarly to both rewarding and aversive stimuli was small (29/271). The effects of both glucose and ICSS, and the effects of both electric shock and tail pinch, were usually similar in neurons analyzed for both rewarding and aversive stimulation. Of 271 neurons, 173 responded differentially to rewarding and aversive stimuli. 4. Neural and behavioral responses were recorded before, during, and after local anesthesia of the VTA in 15 rats and of the AM in 14 rats. Injections of 0.3-0.8 microliters of 5% procaine hydrochloride or 0.9% saline were made at a rate of 0.3 microliters/min through guide cannulae chronically implanted in the VTA and AM, ipsilateral to the recording and ICSS sites in 29 rats that self-stimulated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Skull base metastasis of prostatic cancer presenting as exophthalmos--a case report

A 72-year-old man was admitted to our hospital complaining of diplopia and right exophthalmos. Craniography and CT scan showed thickening of the right orbital roof and no intracranial lesion. Total acid phosphatase and prostatic acid phosphatase were high. Bone scintigraphy revealed high uptake at that lesion and the right pelvis. Unroofing of the right orbit and opening of the optic canal were performed in order to reduce intraorbital pressure. Microscopic examination revealed a metastatic lesion of prostatic cancer. Postoperatively, the patient was treated with "Honvan" and the course has been good.     

Different effects of noradrenaline,angiotensin II and BAY K 8644 on the abolition of autoregulation of renal blood flow by verapamil

Summary To examine the role of Ca channels in autoregulation of renal blood flow in response to changes of perfusion pressure, experiments were performed with perfused kidney in anesthetized dogs using a Ca channel activator, BAY K 8644, and vasoconstrictors such as noradrenaline and angiotensin II. Control observations usually showed excellent autoregulation of renal blood flow at pressures between 120 and 200 mm Hg, the autoregulatory index being less than 0.2. Verapamil (50 g/min, i.a. infusion) obviously inhibited the renal autoregulation. Simultaneous infusion of 5 g/min of BAY K 8644 with verapamil prevented both the increase of renal blood flow and the impairment of the autoregulation caused by verapamil. Whereas simultaneous infusion of noradrenaline (1 and 3 g/min) or angiotensin 11 (0.1 and 0.3 g/min) with verapamil dose-dependently reduced renal blood flow, these drugs could not antagonize the inhibitory effect of verapamil on autoregulation. The present experiments show that Ca channels play an important role in establishing renal autoregulation, and that a mere vasoconstriction by noradrenaline and angiotensin II is distinguished from autoregulatory performance.     

Regional cerebral blood flow (rCBF) in patients with ruptured cerebral aneurysm: site of aneurysm and rCBF

To investigate the relationship between the site of ruptured cerebral aneurysm and rCBF, 92 measurements of rCBF were conducted in 57 patients with ruptured cerebral aneurysm. Excluded from this study were patients with multiple aneurysms, intracerebral hematoma, and/or hydrocephalus. Twenty-four patients had the anterior communicating aneurysm (A-com), 20 patients had the internal carotid aneurysm (ICA), and 13 patients had the middle cerebral aneurysm (MCA). All patients underwent unilateral fronto-temporal craniotomy for clipping of the aneurysm and their rCBF measurements, using the xenon-133 inhalation method, were performed in the first three weeks after surgery. In each rCBF measurement, the hemispheric mean value of initial slope index (meanISI) was calculated in both cerebral hemispheres, that is, in the cerebral hemispheres ipsilateral and contralateral to craniotomy. The authors defined the "symmetry index of the meanISI (%): symmetry index" as the ratio of the meanISI in the cerebral hemisphere ipsilateral to craniotomy compared to the meanISI in the cerebral hemisphere contralateral to craniotomy. There was no significant relationship between the site of aneurysm and the meanISI in both hemispheres, and this result suggests that the site of aneurysm makes no difference in the incidence of vasospasm. In the postoperative first week, the "symmetry index" was 91.2 +/- 7.4% in MCA, 95.3 +/- 4.1% in ICA, and 97.9 +/- 8.2% in A-com; that is, MCA had significant asymmetry of meanCBF compared with A-com (p less than 0.05). In the second and third postoperative weeks, there was no significant relationship between the site of aneurysm and the asymmetry of meanCBF.(ABSTRACT TRUNCATED AT 250 WORDS)