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Biomedical subjects

G C Liu

Publications and source records attributed to G C Liu.

At least 73 records · Page 4Linked to original sources
PubMed1991

Mental retardation in congenital nonprogressive myopathy with uniform type 1 fibers.

A 12-year-old girl with proximal muscle weakness and delayed psychomotor development from early infancy is presented. She had a myopathic face, high-arched palate, nasal tone vocalization, positive Gowers' sign, waddling gait and decreased deep tendon reflexes. Her IQ was 40 (PIQ = 39, VIQ = 51). The serum creatine kinase level and peripheral nerve conduction velocity as well as electrocardiogram were normal. The electromyogram showed myopathic changes. Magnetic resonance imaging (MRI) of thigh muscles revealed fatty infiltration of all muscle groups, the hypertrophic biceps femoris and semimembranous muscles being spared. A biopsy specimen from the left biceps brachii muscle revealed small caliber fibers, increased variability of fiber size and uniformity of type 1 fibers (greater than 99%). This case was diagnosed as having congenital nonprogressive myopathy with uniform type 1 fibers, and had a non-deteriorating clinical course as in most congenital nonprogressive myopathy cases.

Child↗
PubMed1991

[High-resolution computed tomography evaluation of congenital anomalies of the temporal bone].

High-resolution computed tomography (HRCT) was used to study 23 patients with congenital temporal bone deformities. One patient had an inner ear abnormality and 3 patients were combined together with inner, middle and external ear malformations. Embryological development of the outer and middle ears is linked. Development of the inner ear occurs independently. These abnormalities included vestibule dilatation in 2 patients, a lateral semicircular canal defect in 1 case, dilatation of lateral and superior semicircular canals in 1 patient, only dilatation of the lateral semicircular canal in 1 case, oval-window non-development in 3 cases, oval aqueduct dilatation in 1 patient and inner ear abnormalities in 1 case. The study also included 17 cases of unilateral external auditory canal atresia, 5 cases of bilateral atresia, and 1 normal external auditory canal. There were 8 cases of unilateral and 2 cases of bilateral bony atresia. There were 9 unilateral and 1 bilateral cases of membranous atresia. Two cases had bony atresia on one side, with contralateral membranous atresia on the other. Nine unilateral and 2 bilateral cases were positioned superiorly and posteriorly of the mandibular condyle. Thick atresic plate were found in 10 unilateral and 2 bilateral cases. Small tympanic cavities were found in 12 unilateral and 2 bilateral patients; 7 unilateral and 2 bilateral cases had acellular and hypoplastic mastoids. Ossicular deformities were seen in 14 unilateral and 2 bilateral patients. One patient had no ossicle. Anteriorly located descending facial nerve canal was noted in 9 unilateral and 2 bilateral cases. Congenital cholesteatoma was identified in 2 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Gastrointestinal tract involvement in hepatocellular carcinoma: clinical, radiological and endoscopic studies.

Gastrointestinal tract involvement with hepatocellular carcinoma was observed in 8 out of 396 patients (2%) during the course of the disease. Histological involvement was confirmed in 6 cases. All 8 patients were men. The most common clinical presentation was frank gastrointestinal bleeding, which became evident in all cases. Esophageal varices were not seen in any patient. The sites of involvement were the stomach (3), duodenum (4), and jejunum (1). The median time between the diagnosis of primary tumors and gastrointestinal tract involvement was 4.5 months (range: 0 to 12 months). Hematogenous spread was presumed to have occurred in two patients with diffuse-type hepatocellular carcinoma, one of whom had main portal vein thrombosis. Direct invasion by contiguous neoplasm was the major mode of gastrointestinal tract involvement. This complication is more likely to develop in patients with large, subcapsular, massive type hepatocellular carcinoma treated by transcatheter arterial embolization and/or intra-arterial chemotherapy. The median survival after the diagnosis of gastrointestinal involvement was 1 month (2 weeks-4 months).

Adult↗
PubMed1990

Diagnostic value of Tc-99m MAA radionuclide venography of lower extremity: as a simultaneous procedure of ventilation-perfusion scan for pulmonary embolism.

A total of 336 cases received a ventilation-perfusion(V/Q) scan for the detection of pulmonary embolism (PE). Among these, 155 cases simultaneously underwent a successful radionuclide venography study (RNV) of the lower limbs using Tc-99m macro-aggregated albumin (MAA). Concomitant pulmonary arteriography (PA) was performed in 120 cases. Fifty-four of these 120 cases successfully completed the RNV scan. There was a statistical significance in the V/Q scan for the detection of PE as confirmed by the PA (p less than 0.0001). The positive predictive value (PPV) of the RNV for PE was 75% (3/4). The negative predictive value (NPV) was 48% (24/50). The sensitivity and specificity were 10% (3/29) and 96% (24/25) for the 54 patients who had both the RNV scan and PA. For the 155 patients who had simultaneous V/Q and RNV scans, there was no statistically significant correlation between these two scans. The PPV, NPV, specificity and sensitivity were 42%(8/19), 75%(103/136), 90%(103/114) and 20%(8/41), respectively. Despite the low sensitivity and no significance of positive RNV for diagnosis of PE, RNV is still recommendable because it is a simple, non-invasive, simultaneous procedure during perfusion lung scan and has high specificity.

Femoral Vein↗
PubMed1989

[Pulmonary artery sling: diagnosis by magnetic resonance imaging--one case report].

Pulmonary artery sling is an uncommon congenital vascular anomaly, which may cause significant respiratory morbidity resulting from an external tracheal compression during early infancy. This condition should be considered on finding a mass interposed between the trachea and the esophagus showing an anterior indentation on the esophagograms. The diagnosis is usually made by invasive methods such as bronchography, bronchoscopy, cardiac catheterization, and angiography. Magnetic resonance imaging (MRI) has now become an excellent method for diagnosing cardiovascular anomalies, but the use of MRI as a means of diagnosing pulmonary artery sling is rare. In 1988, Malmgren et al, first reported the use of MRI in three cases. Their findings suggested that two overlaping sets of axial sections might be necessary for depicting the anomaly because different parts of the left pulmonary artery are imaged in different slices. In this paper, we report a diagnostic scan image which utilizes a single axial scan and reveals the pulmonary artery sling arising aberrantly from the right pulmonary artery. We also found (a) when the pulmonary artery sling interposed between the esophagus and trachea; the trachea become stenotic below the upper one-third in LAO equivalent sagittal section; (b) the right pulmonary artery compresses the proximal part of right pulmonary bronchus, and the right upper lobe bronchus arises from the trachea independently in the coronal section. Thus, we conclude that MRI, if available, should be the first choice modality for further examination when a pulmonary artery sling is suggested by conventional radiography.

Female↗
PubMed1987

Aortic dissection, a diagnostic dilemma: case report.

A case of type I (type A) aortic dissection proved by postmortem examination could not be fully delineated relative to the type of dissection by dynamic CT as well as three positive contrast aortograms. Small tears in the ascending aorta and their strategic locations can escape even intensive radiologic evaluation. We present a case in which medical therapy was provided and, inappropriately, surgery was not performed.

Aortic Dissection↗
PubMed1987

Loin pain hematuria syndrome.

Loin pain hematuria syndrome occurs primarily in young women and is manifested by recurrent loin pain, hematuria, and abnormal renal vasculature. This syndrome was first described in 1967 by Little in the British literature. Since that time, approximately 60 cases have been reported. In this paper, we describe a case and provide a pertinent review of the literature concerning diagnosis and treatment.

Adult↗
PubMed1986

Inferior vena caval filters: noninvasive evaluation.

Transvenous inferior vena caval filters were placed in 32 patients (21 bird's nest [BN] and 11 Kimray-Greenfield [K-G] filters). Positive contrast cavography was performed before and immediately after filter placement as well as during long-term follow-up studies. In 23 patients, computed tomographic (CT) scanning was also performed; in 10 patients, real-time ultrasound (US) study was used as an adjunct. CT scans of the BN filter showed one case of hemorrhage and one case of air embolism, both of which were not recognized at cavography. CT scanning of the K-G filter demonstrated two cases of deep penetration of the prongs and one large retroperitoneal hematoma. Real-time US scanning played a major role in checking the final position of the filter and in determining its stability during repositioning of the upper prongs of one BN filter. Noninvasive examinations, including CT and US scanning, are valuable adjuncts in immediate and long-term follow-up study of patients with inferior vena caval filters.

Embolism, Air↗
PubMed1986

Effect of anatomic variations on deep venous thrombosis of the lower extremity.

Three hundred thirty-seven lower extremities of 256 patients, both symptomatic and asymptomatic, underwent ascending positive contrast venography. Certain anatomic variations were noted to be related to the location and development of deep venous thrombosis (DVT). The thrombus was located entirely in the calf in 44% of asymptomatic limbs and 17% of symptomatic ones (p less than 0.001). There were multiple superficial femoral veins (SFVs) in 31% of the limbs examined, and 40% of those limbs had DVT. This percentage (40%) represented a statistically higher incidence of DVT (p less than 0.001) than those limbs with a single SFV, where the incidence was only 19%. When limbs with multiple SFVs had DVT, only 41% were symptomatic, whereas in those with a single SFV, 72% of the limbs were symptomatic (p less than 0.001). This difference may be the result of internal collaterals due to multiple SFVs. When there were more than five valves in the deep veins between the popliteal fossa and the ischial spine, there was a higher incidence of DVT (35%) as compared to the incidence when there were five or fewer valves (13%) (p less than 0.001).

Humans↗
PubMed1985

Glyburide in non-insulin-dependent diabetes. Its therapeutic effect in patients with disease poorly controlled by insulin alone.

Glyburide, a second-generation sulfonylurea compound, was combined with insulin to evaluate its therapeutic effectiveness in 14 patients with non-insulin-dependent diabetes mellitus (NIDDM), poorly controlled by insulin alone. Patients were studied before and three months after the addition of glyburide to their insulin program. Fasting plasma glucose concentration fell an average of 57 mg/dL, associated with an approximately 25% reduction in postprandial glucose response. Therapeutic responses varied widely from patient to patient; the greatest improvement in diabetic control was seen in heavier patients, who had retained the ability to secrete insulin in response to meals and who were not excessively insulin resistant. The glyburide-induced fall in plasma glucose concentration was associated with improvements in both insulin secretion and insulin action, but only the enhanced insulin action correlated with the reduction in fasting and postprandial glucose levels. Thus, diabetic control was significantly improved by glyburide. Combined insulin-sulfonylurea therapy may be useful in the treatment of NIDDM that cannot be easily controlled with either agent alone.

Adult↗
PubMed1985

Estimates of in vivo insulin action in humans: comparison of the insulin clamp and the minimal model techniques.

The insulin clamp technique, which is often assumed to measure the ability of insulin to stimulate glucose uptake, actually measures both insulin-independent and insulin-dependent glucose uptake. In contrast, the minimal model technique, recently introduced by Bergman, Philips and Cobelli (1981), attempts to directly estimate insulin sensitivity (insulin-dependent glucose uptake = S1) by measurement of plasma glucose and insulin values during a 3 hour intravenous glucose tolerance test (IVGTT). In the present study estimates of insulin action derived from the insulin clamp and the minimal model technique were compared in 20 humans with varying degrees of glucose tolerance. The insulin response during the IVGTT was too low to permit calculation of S1 in 5 subjects - 4 with Type II diabetes and 1 with normal glucose tolerance. Although the correlation coefficient between the two tests in the other 15 patients was statistically significant (r = 0.53, P less than 0.05), this statement is somewhat misleading. Thus, S1 in the 4/7 patients with Type II diabetes in whom it could be measured was zero, and the correlation between estimates of insulin action with the two techniques in the 11 non-diabetic patients was not statistically significant (r = 0.41, P = NS) when these 4 patients were removed from the analysis. In conclusion, these data indicate that there was only a weak correlation between estimates of insulin action assessed with the insulin clamp and the minimal model techniques. One explanation for this observation is that the insulin-independent component of total glucose disposal both varies widely among patients and contributes significantly to glucose uptake as assessed by the insulin clamp technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Moderate weight loss and sulfonylurea treatment of non-insulin-dependent diabetes mellitus. Combined effects.

Hypocaloric liquid formula diets were given for one month to 20 moderately obese patients with non-insulin-dependent diabetes mellitus divided into two equal groups; group 1 was treated with weight loss alone; group 2 received glipizide in addition to the hypocaloric diet. Mean weight loss was similar in the two groups (6.5 +/- 0.6 v 6.4 +/- 0.5 kg) and was associated with a statistically significant fall in mean fasting plasma glucose values from 293 +/- 15 to 232 +/- 24 mg/dL (group 1) and from 281 +/- 15 to 152 +/- 7 mg/dL (group 2). This was associated with 13% (group 1) and 36% (group 2) decrements in total postprandial glucose response. Neither fasting nor postprandial insulin levels changed significantly with weight loss, but estimates of insulin-stimulated glucose disposal demonstrated a 15% (group 1) and 42% (group 2) improvement. Finally, fasting plasma cholesterol and triglyceride concentrations fell significantly in both groups.

Blood Glucose↗
PubMed1984

Effect of source of dietary carbohydrate on plasma glucose, insulin, and gastric inhibitory polypeptide responses to test meals in subjects with noninsulin-dependent diabetes mellitus.

Previous reports have documented the fact that plasma glucose and insulin responses can vary in response to the ingestion of different carbohydrate-rich foods. This has led to the creation of a "glycemic index," a classification of dietary carbohydrates on the basis of the relative rise in plasma glucose after the administration of the food in question as compared to a standard glucose challenge. In order to test the clinical utility of these observations, we evaluated plasma glucose, insulin, and gastric inhibitory polypeptide responses to four major sources of carbohydrate (potato, rice, spaghetti, lentil) as part of a conventional mixed meal in patients with noninsulin-dependent diabetes mellitus. Each test meal provided 40% of the subjects' calculated caloric requirement and contained 15% of total calories as protein, 40% as fat, and 45% as carbohydrate. The test carbohydrate represented 66% of total carbohydrate. The results indicated that plasma glucose concentrations after meals containing equal amounts of carbohydrate as rice, spaghetti, or lentil were similar and somewhat lower than meals containing potato. The plasma insulin responses to the four carbohydrate foods paralleled the glucose responses. Changes in gastric inhibitory polypeptide levels did not account for the effect of potato. These results are totally disparate from what would have been predicted by previously published values for the "glycemic index" of the four foods studied, and suggest that a "glycemic index" based on isolated challenges would have minimal clinical utility in efforts aimed at reducing postprandial hyperglycemia in patients with noninsulin-dependent diabetes mellitus.

Blood Glucose↗
PubMed1983

Effect of high-carbohydrate-low-fat diets on plasma glucose, insulin and lipid responses in hypertriglyceridemic humans.

Two levels of dietary carbohydrate (40% and 60% of calories) were incorporated into typical US diets and fed for 15 days each to eight patients with endogenous hypertriglyceridemia. Fasting blood samples were drawn on days 13, 14, and 15 of each dietary period, and analyzed for glucose, insulin, cholesterol, and triglyceride concentrations, as well as for triglyceride and cholesterol content of the various lipoprotein classes. In addition, these same measurements were made before and for three hours after the noon meal on days 14 and 15. Fasting plasma triglyceride (TG) and very-low-density lipoprotein (VLDL)-TG concentrations were significantly increased (P less than 0.005) on the low-fat-high-carbohydrate diet. In addition, integrated postprandial insulin, TG, and VLDL-TG responses to the noon meal were significantly (P less than 0.01-0.001) elevated on the low-fat-high-carbohydrate diet. No dietary-induced changes were noted in either the fasting or postprandial values of glucose cholesterol, chylomicron-TG, low-density lipoprotein-cholesterol, high-density lipoprotein (HDL)-cholesterol, HDL2-cholesterol, or HDL3-cholesterol. These results indicate that low-fat-high-carbohydrate diets accentuate the metabolic risk factors for coronary artery disease that are already present in patients with endogenous hypertriglyceridemia.

Adult↗
PubMed1983

Plasma glucose, insulin and lipid responses to high-carbohydrate low-fat diets in normal humans.

Two levels of dietary carbohydrate (40% and 60% of calories) were incorporated into typical U.S. diets and fed for 10 days each to 11 healthy volunteers. Fasting blood samples were drawn on days 8, 9, and 10 of each dietary period and analyzed for glucose, insulin, cholesterol, triglyceride (TG) and high density lipoprotein (HDL)-cholesterol concentrations. In addition, plasma glucose, insulin and TG concentrations were determined before, and for 3 hr after the noon meal on days 8 and 10. No differences were observed in fasting plasma glucose, insulin or cholesterol concentrations. However, fasting plasma TG levels were significantly elevated on the 60% carbohydrate diet, and HDL-cholesterol concentrations were significantly decreased. Furthermore, the plasma insulin and triglyceride responses to the meal tolerance test during the 60% carbohydrate dietary period were significantly elevated. These results indicate that high-carbohydrate diets lead to changes in insulin, TG, and HDL-cholesterol concentrations which have been associated with an increase in incidence of coronary artery disease.

Adult↗
PubMed1978

Plasma squalene: lipoprotein distribution and kinetic analysis.

Plasma squalene concentration is increased in hypertriglyceridemia. In 24 normotriglyceridemic and 12 hypertriglyceridemic subjects, whole plasma squalene correlated strongly with plasma triglyceride (r = 0.973, P < 0.001) in the latter. In normal postabsorptive plasma, squalene was found in each lipoprotein fraction, 50.8% in very low density lipoprotein, 25.6% in low density lipoprotein, and 23.6% in high density lipoprotein. When plasma triglyceride was increased by dietary intake in humans or by experimental diabetes in rats, plasma squalene increased correspondingly. Conversion of [(14)C]mevalonic acid into [(14)C]squalene and kinetic analysis of [(14)C]squalene die-away curves were studied in 17 subjects. Hypertriglyceridemia significantly increased the estimated metabolically active plasma squalene pool. This together with an increase in radioactivity of squalene (dpm/ml plasma) in hypertriglyceridemia suggested that squalene production was increased. Squalene specific activity curves in lipoprotein fractions from four chylomicronemic subjects demonstrated that each fraction had newly synthesized squalene and that total plasma squalene kinetics represent the composite of several individual die-away curves. We conclude that squalene in whole plasma and in lipoprotein fractions varies directly with triglyceride content. Hypertriglyceridemia expands the plasma pool of metabolically active squalene, and each lipoprotein fraction contains squalene that is metabolically active in cholesterol synthesis.

Adult↗