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S S Liu

Publications and source records attributed to S S Liu.

At least 91 records · Page 5Linked to original sources
PubMed1990

PC-based system for retrospective cardiac and respiratory gating of NMR data.

A method and a means for retrospectively clustering NMR k-space measurement profiles with respect to both cardiac and respiratory phases were developed to explore strategies for (1) reducing cardiovascular and respiratory flow/motion image artifacts and (2) improving T1 and T2 characterization of the heart. The image data are collected at a uniform rate so that echo (TE) and repetition (TR) times are independent of the varying cardiac cycle R-R interval and/or respiratory motions. Cardiac (C) time, respiratory (R) time or diaphragm position, and NMR data acquisition (A) cycle time are collected by microcomputer in parallel with free running (untriggered) image collection on a standard magnetic resonance imager. After the raw data equivalent of multiple images are collected, the C-A-R phase timing data are uploaded from the microcomputer to the scanner's minicomputer for use in a normalized C-R phase plane clustering of the image raw data. Each profile's position in the C-R phase plane is determined and then clustered into a new set of data, one image being equivalent for each desired C-R phase combination. These raw data are then zero-filled and (optionally) filtered to compensate for the nonuniform k-space sampling and, finally, reconstructed. Cardiac "cines" made from these retrospectively gated images are comparable to similarly phased triggered images. When high time resolution is required, retrospective gating can be expected to show improvements over triggering, especially toward the critical latter part of the cardiac cycle, where coronary artery filling occurs. The system described can readily be assembled from generally available components.

Electrocardiography↗
PubMed1990

Yolk-sac transmission and post-hatching ontogeny of serum immunoglobulins in the duck (Anas platyrhynchos).

1. To investigate the immunoglobulin (Ig) class which is active in yolk-sac transmission of maternal antibodies in ducks, sera from laying ducks, yolks from their eggs, and sera from ducklings 0-87 days of age were examined by immunoelectrophoresis (IE), and Na2SO4-precipitated Igs from these sera and yolks were run in polyacrylamide gel electrophoresis (PAGE) under reducing conditions. 2. In yolk, 7.8S IgG was greatly enriched compared to 5.7S IgG and IgM, and was the only Ig to reach the sera of newly hatched ducklings. 3. The levels of maternally derived 7.8S IgG in duckling sera decreased after 5 days of age, reaching minimum levels at about 14 days of age. 4. Increases in the serum levels of 7.8S IgG, 5.7S IgG and IgM occurred after 20 days of age, reflecting de novo synthesis by the duckling, and the adult serum profile was achieved by 71 days of age. 5. The involvement of 7.8S rather than 5.7S IgG in yolk-sac transmission was probably determined by the additional heavy chain components of this molecule.

Animals↗
PubMed1990

Intracranial mycotic aneurysm in an infant: report of a case.

Although mycotic aneurysms tend to occur with greater frequency in children than adults, few cases of intracranial infectious aneurysms have been reported in children less than 1 year of age. The case of a previously healthy 7-month-old patient who suffered intracerebral and subarachnoid hemorrhage from multiple aneurysms of the middle cerebral artery is reported. The aneurysms proved to be infectious, based on culture material obtained at surgery from the aneurysm contents and adjacent brain tissue.

Aneurysm, Infected↗
PubMed1990

Synovial cysts of the lumbosacral spine: diagnosis by MR imaging.

Intraspinal synovial or ganglion cysts are uncommon lesions associated with degenerative lumbosacral spine disease. CT usually reveals cystic lesions adjacent to a facet joint, and they may show calcification. MR imaging of four surgically confirmed cases of intraspinal synovial cysts revealed subtle signal changes compared with CSF. Short TR/TE images showed the lesions to be slightly hyperintense in three cases and isointense in one case. Long TR/TE sequences revealed a hyperintense appearance in two cases and a hypointense appearance in the others. A peripheral rim of decreased signal on long TR/TE images probably reflects fine calcification or hemorrhage in the margins of the cysts. The multiplanar and contrast characteristics of MR make this technique well suited to the diagnosis of herniated disk, degenerative facet disease, and synovial cyst.

Aged↗
PubMed1989

Meningioangiomatosis: a case report.

A case of meningioangiomatosis without neurofibromatosis, a rare disorder, is described. These patients are usually young (mean age, 27 years) and frequently present with seizures that resolve following partial or total resection of the lesion. The lesions are firm and well demarcated grossly with areas of calcification. Only single lesions have been described. Neurofibrillary tangles, noted in the present case, have been reported previously, but their significance remains uncertain. The lesion are benign and surgery is recommended.

Adult↗
PubMed1989

Abnormal cardiovascular responses to postural changes and pharmacologic agents in a case of Shy-Drager syndrome.

A 64-year-old carpenter had an unsteady gait, severe dizziness, nocturia, and a loss of erection for more than 4 years. The neurological manifestations consisted of a wide-based ataxic gait, bilateral dysmetria with intentional tremor, staccato speech, rigidity, bradykinesia, and an iris-thinning. There was reproducible orthostatic hypotension. A sweat test revealed severe anhidrosis. Nicotine and methylbenzene sensitivity was absent, whereas norepinephrine infusion test showed a significant elevation of blood pressure. The resting plasma norepinephrine level on recumbency was low and a subnormal surge was noted on standing or exercise. We conclude that the clinical features caused by a degenerative process involving both the central and peripheral autonomic systems, together with atrophy of other systems in this patient, constitute the Shy-Drager syndrome.

Autonomic Nervous System↗
PubMed1988

New subtype of acute odontoid fractures (type IIA).

A new subtype of axis fracture, thought to be a variant of the Type II odontoid fracture, is described. High resolution, thin section computed tomography can assist in the identification of comminuted fractures at the base of the dens with associated free fracture fragments. Because these injuries are markedly unstable and cannot be suitably realigned and reduced by external means, early surgical therapy should be considered.

Acute Disease↗
PubMed1988

Hemophilic pseudotumor of the spinal canal. Case report.

Hemophilic pseudotumor is an uncommon complication among hemophiliacs. Most of these lesions are located in the long bones and the pelvis. The authors describe a case of hemophilic pseudotumor in a patient who presented with symptoms of L-5 radiculopathy and evidence of a destructive lesion on computerized tomography scans. Histologically, the lesion consisted of an organizing hematoma with reactive fibrosis. The diagnosis requires a high index of suspicion. Surgery is recommended for symptomatic patients.

Hematoma↗
PubMed1988

Subunit stoichiometry and interaction of F1-ATPase of beef heart mitochondria.

By incubating soluble F1 of the beef heart mitochondria with radio active 7-chloro-4-nitro-2,1,3-benzoxadiazole (14C)-NBD-C1 in the dark, a labeled F1 with NBD/F1 molar ratio of 1:1 (0.995:1) was obtained, but 98% of the ATPase activity was inhibited. The inactivated ATPase activity of the NBD-labeled F1 may be restored by DTT, suggesting that an essential tyrosine residue of F1 (O-NBD-F1) may be labeled. By exposure of O-NBD-F1 with 0.83 NBD label per F1 molecule and a stable 82.5% inhibition of the ATPase activity even in the presence of DTT. Urea PAGE analysis clearly showed that a 63.4% of the total radio activity was associated with the beta-subunit. In the beta-fraction from N-NBD-F1 only a 19.90-20% of the labeling was detected. It is calculated that F1 of the beef heart mitochondria contains 3 (2.63-2.64) beta-subunits. The results obtained are discussed in connection with the subunit-subunit and site-site interactions and three-site model for F1 catalysis proposal by Boyer and his group.

Animals↗
PubMed1987

Plasma levobunolol levels following topical administration with reference to systemic side effects.

We determined the plasma level of levobunolol in normal volunteers after a single topical instillation of 0.5 or 1% levobunolol in both eyes, and after twice-daily instillations for 1 week. Levobunolol levels were detected within 1 h following acute instillation. During the study, mean plasma levels ranged from 0.1 to 0.3 ng/ml for the 0.5% group and 0.3 to 0.6 ng/ml for the 1% group. The highest individual plasma level was 1.2 ng/ml, which occurred in 1 patient receiving 1% levobunolol. After 1 week of twice-daily instillation mean plasma levels were similar to those observed after acute instillation. Minimal cardiovascular changes were observed in the 0.5% group while decreases in heart rate and systolic blood pressure were observed in the 1% treatment group.

Administration, Topical↗
PubMed1986

[Primary rhabdomyosarcoma of the heart--a case report].

The patient, a 33 year old male, had suffered from swelling of the chest, neck and face for 4 months; palpitation, chest and epigastrium pain, cough and yellowish sputum for 10 days before admission into our hospital. Blood routine and erythrocyte sedimentation rate were normal. By X-ray examination, the right upper mediastinum was obviously widened with the trachea displaced toward the left and pleural effusion was present on both sides. On day 5 of admission, the patient died of heart failure. The clinical diagnosis was not clear but lymphosarcoma or other malignant tumors in the mediastinum was suspected. Autopsy was performed. A large tumor 8 X 10 X 2.5 cm in size was found in the right atrium. The tumor had a short and broad pedicle (6 X 5 cm in diameter) connected with the upper part of the atrial wall. The histological diagnosis was primary rhabdomyosarcoma of the heart.

Adult↗
PubMed1985

Alpha-1-antitrypsin types in five Chinese national minorities.

The frequencies of alpha-1-antitrypsin alleles were determined for five Chinese national minorities: Uigur, Korean, Mongolian, Chuang, and Li. PI S and PI Z alleles are not found in the five populations studied. PI ETOK allele is present in Korean, Mongolian, and Chuang populations, and Etokyo is a very common alpha-1-antitrypsin variant in Chinese. Other alleles which occur in more than one of the minorities are PI X (Mongolian and Chuang) and PI M4 (Korean and Uigur). The high frequency of PI M4 in the Uigur population suggests a probably Occidental origin of this nationality.

Alleles↗
PubMed1984

Ocular and systemic bioavailability of ophthalmic flurbiprofen.

Flurbiprofen, a nonsteroidal antiinflammatory agent which is not ocularly metabolized, was employed as a probe compound to investigate the drug kinetic relationship between systemic and ocular humoral circulation. The ocular and systemic bioavailabilities of topically applied flurbiprofen were also quantitated. Anesthetized albino female rabbits received flurbiprofen doses intracamerally, topically, and intravenously at 2 to 4 week intervals. Aqueous humor and plasma were used as the sampling compartments. Plasma clearance values of flurbiprofen were 6.77 and 7.87 ml/min, after 6-mg and 208-micrograms intravenous doses, respectively. These values were not significantly different and indicated no dose-dependent disposition kinetics over a 30-fold dose range. Both ocular and systemic flurbiprofen dispositions followed a biexponential pattern with a rapid distribution phase. The systemic and ocular distribution half-lives of flurbiprofen were 12 min and 15 min, respectively. The plasma elimination half-life was 74 min and the aqueous humor elimination half-life was 93 min. The latter approximated the turnover rate of aqueous humor and suggested that aqueous humor drainage was the major process of flurbiprofen elimination from the globe. About 99% of flurbiprofen is bound to plasma protein. At distribution equilibrium, the plasma and aqueous humor concentrations of flurbiprofen differed by a hundredfold, suggesting that only free drug entered the aqueous humor after the administration of a systemic dose. In the ophthalmic studies, right eyes were instilled with 50 microliters of 0.3% flurbiprofen in saline (dose = 150 micrograms), and left eyes were instilled with 50 microliters of 0.15% flurbiprofen in saline (dose = 75 micrograms). When the area of the aqueous humor concentration-versus-time curve values was normalized by the administration dose, the 75-micrograms dose was 30% more available to ocular tissues than was the 150-micrograms dose. This demonstrated a disproportionate relationship between the administered dose and the fraction absorbed. The intracameral dose was considered to be completely bioavailable for intraocular effects. The ocular bioavailability of the ophthalmic dose was defined by using intracameral administration as a standard measurement. The ocular bioavailabilities of the 75-micrograms and 150-micrograms topical flurbiprofen doses were 10% and 7%, respectively. Systemic bioavailability after topical administration of 225 micrograms of flurbiprofen was 74%.

Administration, Topical↗
PubMed1983

Retinal hexokinase: kinetic properties and the effect of cyclic 3',5'-adenosine monophosphate.

We measured hexokinase (EC 2.7.1.1) activity in particulate and soluble fractions isolated from bullfrog (Rana catesbeiana) retinas. Seventy-three percent of the hexokinase (HK) activity was associated with the particulate fraction, 27% with the soluble fraction. Both HK fractions could phosphorylate fructose, glucose, 2-deoxy-D-glucose, and mannose, but not galactose. The Km for glucose was 0.14 mM, for 2-deoxy-D-glucose, 3.6 mM. With glucose as substrate, the Vmax for particulate HK was 125-148 microM retina-1 min-1, for soluble HK, 37 microM retina-1 min-1. Product inhibition of particulate HK activity by glucose 6-phosphate was marked, whereas 2-deoxy-D-glucose 6-phosphate did not inhibit the activity. Cyclic AMP stimulated the HK activity of both retinal fractions nearly twofold at concentrations of 0.2-0.8 mM; AMP was much less effective in this regard.

Animals↗