High-density Spots Research Articles

Visual field organization and retinal resolution in the beluga whale Delphinapterus leucas (Pallas).

The distribution and size of ganglion cells in the retina of three retinal wholemounts of beluga whales ( Delphinapterus leucas )w ere investigated. Cell sizes were from 12 to 48 # mw ith monomodal size distribution. Ganglion cells concentrated at two spots of high density in the nasal and temporal quadrants, 50 to 60% from the optic disk. Both areas appeared as vertically elongated spots. The mean peak cell density over all wholemounts in the temporal and nasal areas was 400 and 300 cells/mm 2 , respectively. With ap osterior nodal distance of 12 m, these cell density corresponded to 17.4 cells/ deg 2 and 12.7 cells/deg 2 ,w hich provided an underwater retinal resolution of 14.4& (2.2 cycle/deg) and 16.9& (1.8 cycle/deg) in the temporal and nasal highdensity areas, respectively, and aerial resolution of 19.2& (1.6 cycle/deg) and 22.5& (1.3 cycle/deg). These data suggest that the beluga whale has slightly poorer visual acuity than other marine odontocetes investigated so far.

Potentiation of phosphoinositide-derived signals during LTP in intact rat brain.

In order to examine the relationship between long-term potentiation (LTP) and phosphoinositide (PI) turnover, we evaluated these throughout anesthetized rat brain using carbon-11-labeled diacylglycerol (11C-DAG). High-frequency tetanic stimulation (400 pulses at 400 Hz) to the perforant pathway induced LTP in rat dentate gyrus. In autoradiograms of rat brains, LTP was associated with the occurrence of multiple highly radioactive spots in many regions distant from the stimulated site. Following i.v. administration of an NMDA receptor antagonist prior to stimulation, however, no high-density spots were found. These findings directly demonstrate that potentiation of phosphoinositide-derived signaling was induced during LTP, and the finding of multiple location suggests the occurrence of polysynaptic neurotransmission through neural networks pertaining to learning and memory.

Obstructive sialadenitis caused by intraparotid deposits of gold salts: A case report

A case of obstructive sialadenitis caused by deposits of gold salt compound in the intraparotid lymphoid tissues in a woman with classic rheumatoid arthritis is presented. The patient had been treated with a parenteral gold salt compound (sodium aurothiomalate) for 10 years with chrysotherapy balance of 7525 mg. She presented with swelling of both parotid glands on eating, and computed tomography images showed accumulation of high density spots. Obstructive sialadenitis most probably was caused by local compression on the excretory ducts of the parotids. This clinical disorder should be classified as a case of mechanical, nontumoral, obstructive sialadenitis caused by gold salt compound.

Infantile subdural fluid collection: diagnosis and postoperative course

The authors reviewed 47 cases of infantile subdural fluid collection with regard to diagnosis and postoperative course after placement of a subdural-peritoneal shunt. CT scan with contrast enhancement proved to be an important diagnostic modality, showing vessels in the subarachnoid space as high-density spots. Utilizing this technique, we were able to differentiate the following varieties of fluid collection: (1) subdural fluid collection, in which enhancing vessels were seen on the brain surface, (2) subarachnoid fluid collection, in which vessels were on the inner table of the cranium, and (3) coexistence of subdural and subarachnoid fluid collections, in which vessels were between the inner table of the cranium and the brain surface. The postoperative course of subdural fluid collection was characterized as follows: (1) the subdural fluid collection decreased first, with increased subarachnoid fluid collection; (2) the subarachnoid fluid collection remained after the disappearance of subdural fluid collection; and (3) the brain expanded again later. Subdural fluid collection disappeared about 1 month after the shunt operation, which could lead occlusion of the shunt system. Postoperative enlargement of the subarachnoid space was an early indicator of the efficacy of the subdural-peritoneal shunt.

Pseudolipoma of Glisson???s Capsule

We report six cases of pseudolipoma of Glisson's capsule. The patients ranged from 53 to 83 years old (mean 67.7 years), and all were men. Pseudolipoma of Glisson's capsule was detected by imaging studies before operation in two cases, and noted incidentally in the remaining four. Computed tomography demonstrated a subcapsular low-density nodule with or without a high-density spot. All but one patient had a history of abdominal operation. Grossly, the pseudolipoma was a solitary encapsulated nodule on the surface of the anterior aspect in five, and posteroinferior to the right lobe in one. The pseudolipomas ranged from 0.5 to 2 cm in diameter, were white to yellowish-white and elastic-firm. Histologically, the nodules had a dense fibrous capsule and contained necrotic mature fat tissue. In addition, three showed focal calcification. Blood vessels were rarely found within the capsule. These findings strongly suggest that history of abdominal operation, advanced age, sex, and poor blood supply to the nodule are causal to their development. Although only 18 cases have been reported previously, our six cases during but a 3-year period suggests that it may not be as rare as believed.

Use of a disjunctive kriging to model areas of high pelagic fish density in acoustic fisheries surveys

Resume Schooling fish may aggrcgate in vcry high dcnsitics covering very small areas. Thus the probability of hitting such high-density spots during a large-scalc sampling is vcry low. Thc sampling fluctuations of the tail of the histogram are thought to be very significant. The stock biomass cstimate and its precision rely greatly on how prcciscly thc tail of the histogram can be sampled. In order to acquire clcmcnts for improving survey designs and abundance estimators WC study hcrc thc relation in space that thc high valucs have with the other values. A disjunctive kriging approach is used. Differcnt quantiles of the histogram arc codcd by indicators. The spatial structure of each indicator and its spatial covariation with the others are studied by computing cxpcrimcntal indicator variograms and cross-variograms. Such analysis is applied to dissect finely the spatial structure of a Norwegian herring stock sampled acoustically. It is shown that when going from low-density arcas to high-density ones, intcrmediate values are not necessarily crossed. Thus a particular disjunctive kriging modcl with no transition in space is wcll adaptcd to the herring data. The model is based on the regressions of each indicator on the one immediately below it. In the modcl one can cstimatc the probability for the fish density to trespass a given cut-off at a given location when knowing that the density trcspasscs lowcr cut-offs at surrounding points. It is shown on the data that the high densities are structured and show small aggregations. Then it is shown that having trespasscd a certain cut-off, i.e. inside the corresponding areas in space, the high-density aggregations can be considered to be positioned independently from the other values. These areas, where the structuring of the high values is not correlated to the structuring of the other values, are mapped using the fittcd disjunctive kriging model. The implications for survey designing of the existence of such areas and of their geometry are discussed. AIso discussed is the possibility of stratifying the data in spatially uncorrelated boxes when deriving the biomass estimate and its precision, on the basis of an observed spatial non-correlation property between the spatial distribution of different quantiles.

Pinch spot formation in high atomic number z discharges.

A nonlinear, quasi-two-dimensional model for pinch spot formation in radiation-dominated, high atomic number z pinches is presented that reproduces the experimental electrical and radiation characteristics. The high line-radiation rates of such discharges produce localized, high-density pinch spots in contrast to the spindle pinches predicted for hydrogenic discharges.

ABSCESS OF THE APPENDICITIS DUE TO AN ARTIFICIAL TOOTH -REPORT OF A CASE-

An artificial tooth swallowed in error caused appendiceal abscess 2 years later. This case is described with reference to the literature. A 47-year-old man was presented with lumbago and fever, as well as right lower abdominal pain, which had been disregarded. Physical examination revealed knock pain over the right lumber region, tenderness and peritoneal signs in the right lower quadrant. The body temperature was 38.2°C with a leukocyte count of 12500. Microscopic hematuria was not recognized. Abdominal radiography revealed a radiopaque foreign body, 10×8 mm in size, in the right lower quadrant. Enhanced CT disclosed a uniform low density area in the right ileopsoas muscle with a high density spot in the retroperitoneal cavity. An emergency operation was performed under a diagnosis of appendiceal abscess due to a foreign body. An appendix showing inflammatory swollen was extensively adhesive to the retroperitoneum and ileopsoas muscle.There was an egg-sized abscess in the ileopsoas muscle. Appendectomy was completed with drains left in the peritoneal cavity and abscess. The excised appendix contained the artificial tooth which had been swallowed 2 years before. This experience suggested the importance of a careful study on anamnesis and abdominal plain films for diagnosing appendicitis due to foreign bodies before operation.

Interpeduncular high-density spot in severe shearing injury

Thirty cases of severe shearing injury were analyzed utilizing serial computed tomography scans and clinical observations. Fatalities occurred in the majority of patients whose Glasgow Coma Scale scores at admission were 6 or less. The presence of perimesencephalic subarachnoid hemorrhage, hemorrhage in the corpus callosum, acute brain swelling, and intraventricular hemorrhage on computed tomography scans resulted in high mortality rates. In 13 patients, interpeduncular high-density spots were observed on computed tomography scans, which were performed in the acute stage of injury. Eight of these patients died, and those surviving had poorer neurological outcomes than corresponding patients with identical Glasgow Coma Scale scores on admission. In the management of severe shearing injury patients, more attention should be given to the presence of interpeduncular high-density spots as well as other important diagnostic computed tomography findings regarding diffuse brain injury.

Ligand autoradiographic receptor screening: receptor cDNA expression in replicas of transfected COS cells

In this paper we validate a methodology, ligand autoradiographic receptor screening (LARS), for detecting expression of full length receptor cDNAs in COS cells. The method involves transfection of COS cells with receptor cDNAs by spheroplast fusion, production of filter replicas of the cell fragments, ligand binding to the receptors expressed in the membranes, and autoradiographic detection of bound ligand. A β-adrenergic receptor cDNA cloned into a eukaryotic expression vector reliably induces high levels of β-adrenergic receptor expression in 2–12% of COS cell colonies transfected with this plasmid after experimental conditions are optimized. Receptor expression is monitored by autoradiographic detection of 125iodocyanopindolol binding to COS cell fragments immobilized on polyester filter replicas. Binding displays appropriate pharmacological properties. The number of high-density binding spots per filter depends on the fraction of the spheroplasts in the fusion mixture that contain the β-adrenergic receptor cDNA. A 100-plate LARS experiment can assess receptor expression in more than 10 4 transfected colonies. Thus detection of receptor-encoding sequences present in libraries in proportions as low as 1 in 10 4 should be possible. This technique may therefore be useful in detecting expression of other receptor cDNAs for which selective radioligands are available.

Anode spot plasma torch

With acetone as a catalyst in an argon discharge plasma, it is observed that localized high-density anode spots can be formed at sharp edges in the plasma. By placing the sharp edge on top of a small permanent magnet, the current which is attracted to the spot can locally burn a piece of metal beneath the sharp edge. It is believed that the practical significance of these results may have wide implications for plasma processing or plasma burning applications.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

口蓋へん桃の超音波診断装置による観察

With ultrasonic tomography palatine tonsils (p.t.) and the paratonsillar regions were imaged in viva. The longitudinal and transverse measurements in 65 tonsils were compared with actual size of these tonsillar tissues after tonsillectomy. We also analyzed the images of the tonsils in 165 normal subjects and in 43 patients with palatine tonsillar diseases (39 with recurrent tonsillitis, one with acute tonsillitis and one each with peritonsillitis, peritonsillar abscess and paratine tonsillar tumor).An ultrasonic apparatus, SSD-256 (Aloka Co. Ltd), and a 7.5MHz probe which were commonly used to examine the carotid arteries were employed. After setting the probe on the submandibular area, we analyzed the images of the p.t. The tissue of the p. t. appeared as a low density shadow, and the plugs in the p. t. as high density spots. In the paratonsillar region, the tongue, the superior constrictor muscles of the pharynx, and the tonsillar branches could also be demonstrated ; the images of the tongue and the sup. const. muscle of the pharynx were high density shadows, while the tonsillar branch appeared as a low density shadow.There was a significant correlation between the ultrasonic measurements and the actual longitudinal and transverse diameters in the 65 tonsils.In normal subjects, images of plugs were not visible or were very faint.Patients with recurrent tonsillitis had many plugs, and the image of the tonsillar capsule was wide and clear from the inferior pole to the superior pole.The image of a localized abscess was clear in the patient with peritonsillar abscess, and that of invasive tumor in the patient with tonsillar tumor.Ultrasound imaging is expected to be useful in the diagnosis and therapy of palatine tonsillar disease.

Multiple echogenic sports in spleen: Gandy-Gamna nodules in congestive splnenomegaly

We report a case showing multiple widespread echogenic foci in ultrasonogram and multiple high density spots in computed tomogram in spleen, which has congestive splenomegaly secondary due to liver cirrhosis and portal vein thrombosis. Pathologically the lesions in spleen correspond with mainly homosiderin deposits in Gandy-Gamna nodules seen in congestive splenomegaly.

Single- and multi-channel currents recorded with patch electrodes in mouse eggs

Zona-free mouse eggs are amenable to patch recording as well as to whole-cell recording (Bland et al., 1984; Peres, 1986a). Although many patches are silent, others show spontaneous channel opening; the single channel current is 1.5 pA and inwardly directed at resting potential (RP). Current amplitudes distribute normally as a single population at RP, however at RP — 50 mV the amplitude histogram indicates two channel populations. Open time distribution is exponential with a mean open time between 4 and 7 msec at RP. In three cases out of thirty-eight, in which depolarizations were given from a holding potential of RP — 50 mV, microscopic currents very similar in kinetics and voltage-dependence to the whole-cell Ca 2+ current were observed. No single-channel currents could be resolved in these traces. The results reported here indicate that the voltage-dependent Ca 2+ current of the mouse egg goes through low-conductance channels located in high density spots on the egg surface.

CARDIAC RHABDOMYOMA ASSOCIATED WITH TUBEROUS SCLEROSIS

An autopsy case of cardiac rhabdomyoma associated with tuberous sclerosis in a 27-day-old infant is presented. He was born with severe cyanosis. Echocardiogram revealed the presence of multiple mass lesions, some of which protruded into the left ventricle at the level of subaortic valve. From the age of 4 days, cardiac arrhythmia developed and lasted until his death. The arrhythmia started as WPW syndrome and atrial extrasystoles and then additional paroxysmal supraventricular tachycardia, ventricular fibrillation, sinus arrest, and S-A block occurred. Computed tomographic scanning of the brain revealed the presence of symmetric high-density spots around the central part of lateral ventricle. Before his death paroxysmal supraventricular tachycardia occurred frequently which changed to ventricular fibrillation and he collapsed without urination and then died. Autopsy examination revealed the presence of generalized congestion, multiple nodules of cardiac rhabdomyoma, some of which causing subaortic stenosis, and tuberous sclerosis in the brain. From the clinical and autopsy findings, the direct cause of death was attributable to the cardiac rhabdomyoma.

Formation of acetylcholine receptor clusters at neuromuscular junction in Xenopus cultures

The formation of acetylcholine receptor (AChR) clusters at the neuromuscular junction was investigated by observing the sequential changes in AChR cluster distribution on cultured Xenopus muscle cells. AChRs were labeled with tetramethylrhodamine-conjugated α-bungarotoxin (TMR-αBT). Before innervation AChRs were distributed over the entire surface of muscle cells with occasional spots of high density (hot spots). When the nerve contacted the muscle cell, the large existing hot spots disappeared and small AChR clusters (less than 1 μm in diameter) initially emerged from the background along the area of nerve contact. They grew in size, increased in number, and fused to form larger clusters over a period of 1 or 2 days. Receptor clusters did not migrate as a whole as observed during “cap” formation in B lymphocytes. The rate of recruitment of AChRs at the nerve-muscle junction varied from less than 50 binding sites to 1000 sites/hr for αBT. In this study the diffusion-trap mechanism was tested for the nerve-induced receptor accumulation. The diffusion coefficient of diffusely distributed AChRs was measured using the fluorescence photobleaching recovery method and found to be 2.45 × 10 −10 cm 2/sec at 22°C. There was no significant difference in these values among the muscle cells cultured without nerve, the non-nerve-contacted muscle cells in nerve-muscle cultures, and the nerve-contacted muscle cells. It was found that the diffusion of receptors in the membrane is not rate-limiting for AChR accumulation.

Large Archival Mass Memory System Using Optical Diskettes

The transition of digital optical mass storage technologies from the laboratory to an integrated deliverable system is a challenge whose time has come. Harris Corporation has accepted the challenge and will deliver a 1013 bit Archival Mass Memory (AMM) System. AMM provides: variable data ingest rates up to 50 Mbits/sec accommodating sources as diverse as telephone links, computer links, and satellite downlinks; Reed-Solomon error detection and correction (EDAC) coding to preserve better than a 10 -9 bit error rate (BER) for up to 10 years of operation without rerecording; real time optical spot recording of 109 user bits on each 148 X 148 mm diskette; storage and automatic on-line retrieval of data from 1024 diskettes housed in each storage and retrieval unit; less than 15 second access time to any record in the archive; simultaneous data recording and readout; forward file management for rapid user-oriented access down to the byte level; simultaneous access to multiple modular storage and retrieval units; and variable output rates up to 50 Mbits/second direct or interleaved for multiple variable rate users tied to the fiber-optic distribution bus. This paper outlines the system design and performance including the complex electro-optic technologies employed to provide high-speed high-density optical spot recording and readout.

Two types of delayed post-traumatic intracerebral hematoma.

The findings of repeated CT scans, clinical courses and pathological studies in 28 cases of delayed post-traumatic intracerebral hematoma were studied retrospectively to elucidate the mechanism of bleeding and to establish adequate treatment. Based on the results obtained, it became clear that there are two types of delayed hematoma. In 10 of the 28 cases, initial CT findings within 6 hours after head injury revealed cerebral contusion or hemorrhagic contusion, and spots of high density scattered in the low density zone gradually became confluent to form an irregularly shaped hematoma according to follow-up CT findings. This was termed “hematoma within a contusional area.” In 15 of the 28 cases, initial CT findings within 6 hours after head injury revealed no abnormal density within the brain and the hematoma appeared suddenly 3 ?? 6 days after the injury. In eight of the 15 cases, emergency surgery was performed for the removal of epidural or subdural hematoma. This type of hematoma is termed “contusional hematoma” and constitutes the second group. In three of the 28 cases, both types of hematoma were observed. Based on histological findings for the two types of delayed hematoma. The first group may be induced by an anoxic vasodilation mechanism (Evans et al.9)), while the second group may be derived from a different mechanism related to ishemic changes and the free radical reaction caused by the reflow phenomenon (Tsubokawa et al.14-16)) It is important to establish correct diagnoses 1 for delayed hematomas based on differences between follow-up findings of repeated CT and an initial CT performed within 6 hours after head injury since the operative indications and operative results for the two groups are different as indicated by our 28 cases.