Biomedical subjects

T S Chen

Publications and source records attributed to T S Chen.

At least 55 records · Page 3Linked to original sources

PubMed1998

Regulation of classic and alternative bile acid synthesis in hypercholesterolemic rabbits: effects of cholesterol feeding and bile acid depletion.

The effect of cholesterol feeding (3 g/day) on bile acid synthesis was examined in 10 New Zealand white rabbits (NZW), 8 Watanabe heterozygous and 10 homozygous rabbits with partial and complete deficiencies of LDL receptors. After 10 days of cholesterol feeding, bile fistulas were constructed and bile acid pool sizes were measured. Cholesterol feeding increased plasma and hepatic cholesterol levels in all rabbit groups. Baseline bile acid pool sizes were smaller (P < 0.01) in heterozygotes (139 +/- 3 mg) and homozygotes (124 +/- 30 mg) than NZW rabbits (254 +/- 44 mg). After feeding cholesterol, bile acid pool sizes doubled with increased cholic acid synthesis in NZW and, to a lesser extent, in Watanabe heterozygous rabbits but not in homozygotes. Baseline cholesterol 7alpha-hydroxylase activity in NZW and heterozygotes declined 69% and 53% (P < 0.001), respectively, after cholesterol feeding. Sterol 27-hydroxylase activity reflecting alternative bile acid synthesis increased 66% (P < 0.01) in NZW and 37% in Watanabe heterozygotes but not in homozygotes after feeding cholesterol. Bile fistula drainage stimulated cholesterol 7alpha-hydroxylase activity but not sterol 27-hydroxylase activity in all three rabbit groups. These results demonstrated that dietary cholesterol increased hepatic sterol 27-hydroxylase activity and alternative bile acid synthesis to expand the bile acid pool and inhibited cholesterol 7alpha-hydroxylase in NZW and in Watanabe heterozygous rabbits but not in homozygotes with absent hepatic LDL receptor function. Thus, in rabbits, sterol 27-hydroxylase is up-regulated by the increased hepatic cholesterol that enters the liver via LDL receptors whereas cholesterol 7alpha-hydroxylase is controlled by the circulating hepatic bile acid flux.

Animals↗

PubMed1997

A study on biliary ductal system and bile fistula in the American alligator, Alligator mississippiensis.

The anomalous arrangement of bile ducts in the Crocodylia has not been fully appreciated. A clear understanding of biliary anatomy is necessary in order to create complete bile drainage in these reptiles. The object of this study was to clarify the anatomy of the bile ductal system and to establish total bile fistulas in the American alligator, Alligator mississippiensis. Bile duct anatomy was studied in 104 juvenile alligators, and bile fistulas were constructed in seven alligators. In 93 out of 104 (89%) of the juveniles dissected there was an interconnection between the right and left hepatic duct before the right hepatic duct emptied into the gallbladder. The left hepatic duct then entered the duodenum independently of the cystic duct which drained the gallbladder directly into the duodenum. In 8% of the animals, the left hepatic duct did not enter the duodenum but joined with the right duct, forming a common hepatic duct that emptied into the gallbladder. In 3% of the cases, the right hepatic duct emptied into the gallbladder, while the left duct had no communication with the right hepatic duct and drained separately into the duodenum. This arrangement of bile ducts is similar to that seen in birds and reflects the common ancestry of crocodiles and birds. In other reptiles, the biliary system shows much more variability and is different from the alligator. In five of seven alligators in which total biliary diversion was attempted, the biliary catheter remained in place and stayed patent from 2-7 weeks. Bile flow was extremely low (1.5-2.5 ml/24 h) when compared to that of mammals (80-100 ml/24 h). This study demonstrates the variable nature of the biliary ductal system in Alligator mississippiensis and suggest a method for constructing an effective total bile fistula in these animals.

Alligators and Crocodiles↗

PubMed1997

Action of Taiwan cobra cardiotoxin on membranes: binding modes of a beta-sheet polypeptide with phosphatidylcholine bilayers.

The interaction of Taiwan cobra cardiotoxin (CTX A3), a basic polypeptide consisting of three-fingered loops and five-strand beta-sheet structure, with zwitterionic dipalmitoylphosphatidylcholine (DPPC) has been studied by 31P and 2H NMR to understand the binding modes of CTX in membrane bilayers. The results, in conjunction with DPH fluorescence anisotropy and differential scanning calorimetry studies, show that CTX may penetrate and lyse the bilayers into small aggregates at a lipid/protein molar ratio of about 20 in the ripple Pbeta' phase. Elevating the temperature to that of the liquid crystalline Lalpha phase leads to the fusion of the small aggregates into larger ones as evidenced by the change of the isotropic signal into a magnetically aligned 31P signal with a marked reduction in the chemical shift anisotropy. 2H NMR study on deuterium-labeled DPPC in the head group and fatty acyl region as a function of temperature and CTX concentration reveals a molecular model that CTX undergoes a redistribution between penetrating and peripheral binding states depending on the temperature studied. In addition, both the conformational and dynamic states of the phosphocholine head group of DPPC bilayers are significantly perturbed in the presence of CTX. Structural consideration of the CTX molecule indicates that the penetration binding mode of CTX with the DPPC bilayer may involve a novel membrane-binding motif identified recently in the three-fingered loops of P-type CTX. CTX can only bind to DPPC membrane peripherally in the Lalpha phase due to the mismatch of their hydrophobic lengths.

Calorimetry, Differential Scanning↗

PubMed1997

Screening for abnormal cholesterol biosynthesis in the Smith-Lemli-Opitz syndrome: rapid determination of plasma 7-dehydrocholesterol by ultraviolet spectrometry.

The Smith-Lemli-Opitz syndrome (SLOS) is a common condition caused by deficiency of 7-dehydrocholesterol delta 7-reductase. The syndrome can usually be diagnosed by demonstrating markedly increased plasma concentrations of the cholesterol precursor, 7-dehydrocholesterol. We describe a simple and rapid method for detection of plasma 7-dehydrocholesterol by use of ultraviolet (UV) spectrometry. Lipids were extracted from plasma by addition of ethanol and n-hexane, and the n-hexane phase was directly subjected to spectrometry. The absorption maxima characteristics of 7-dehydrocholesterol (lambda max 271, 282, and 294 nm) were observed in patients' plasma but not in controls. For quantitative measurements, absorbance at 282 nm was used. Since this absorbance is the sum of the absorbance derived from 7-dehydrocholesterol and background absorbance, the concentrations of 7-dehydrocholesterol in various plasma samples were quantified by subtracting estimated background absorbance at 282 nm from observed absorbance at 282 nm. The results correlated well with total (free plus esterified) 7-dehydrocholesterol concentrations measured by gas-liquid chromatographic method. The UV spectrometric assay was sensitive enough to detect increased 7-dehydrocholesterol in cultured skin fibroblasts from patients grown in delipidated medium. The present method will make it possible to screen plasma or fibroblasts to detect the syndrome rapidly in general clinical laboratories.

Cells, Cultured↗

PubMed1997

Sterol concentrations in cultured Smith-Lemli-Opitz syndrome skin fibroblasts: diagnosis of a biochemically atypical case of the syndrome.

The Smith-Lemli-Opitz syndrome is a common birth defect syndrome caused by a deficiency of 7-dehydrocholesterol delta 7-reductase, an essential enzyme in the biosynthesis of cholesterol. The syndrome can usually be diagnosed easily from the plasma markers of markedly elevated 7-dehydrocholesterol and reduced cholesterol concentrations. However, atypical cases with normal plasma levels of cholesterol with only moderately elevated 7-dehydrocholesterol have been reported. To establish a sensitive method for the biochemical diagnosis of the atypical cases of the syndrome, we measured sterol concentrations of cultured skin fibroblasts. 7-Dehydrocholesterol concentrations in patients' fibroblasts grown in the presence of 10% fetal bovine serum were significantly higher than those in controls and parents (P < 0.0005), but they were not elevated proportionately as much as in plasma. To re-produce the accumulation of 7-dehydrocholesterol, the cells were exposed to delipidated medium to induce sterol biosynthesis. After 4 weeks, 7-dehydrocholesterol concentrations in patients' fibroblasts increased from 2.8 +/- 0.3% to 34 +/- 3% of total sterols (cholesterol + 7-dehydrocholesterol + 8-dehydrocholesterol). The increase was also observed in fibroblasts from an atypical patient who has a normal plasma cholesterol level and a 7-dehydrocholesterol concentration of only 0.15 mg/dl. In contrast, cells from parents and controls accumulated very little 7-dehydrocholesterol (< 1% of total sterols). These results demonstrate that cultured fibroblasts exhibit abnormally high accumulation of 7-dehydrocholesterol after cells are exposed to delipidated medium not only in typical patients, but also in an atypical case. The present method is a sensitive procedure for the biochemical diagnosis of this syndrome.

Adolescent↗

PubMed1997

Increased bile acid pool inhibits cholesterol 7 alpha-hydroxylase in cholesterol-fed rabbits.

BACKGROUND & AIMS: Cholesterol feeding unexpectedly inhibits cholesterol 7 alpha-hydroxylase in rabbits. The aim of this study was to explore the mechanism. METHODS: Twenty male New Zealand white rabbits were fed regular chow with and without 2% cholesterol for 10 days followed by 7 days of bile drainage. The activities of hepatic cholesterol 7 alpha-hydroxylase and sterol 27-hydroxylase that control bile acid synthesis in classic and alternative pathways were related to the size and composition of bile acid pool. RESULTS: After feeding cholesterol, plasma and hepatic cholesterol concentrations increased, the bile acid pool doubled (from 254 +/- 44 to 533 +/- 51 mg; P < 0.001), cholesterol 7 alpha-hydroxylase activity decreased 68% (P < 0.01), but sterol 27-hydroxylase activity increased 66% (P < 0.05) with increased cholic acid synthesis (P < 0.01). Bile drainage in the cholesterol-fed rabbits depleted the bile acid pool and stimulated down-regulated cholesterol 7 alpha-hydroxylase activity 11.4-fold (P < 0.001), although hepatic cholesterol remained elevated. Hepatic sterol 27-hydroxylase activity was unaffected. CONCLUSIONS: Feeding cholesterol increased hepatic cholesterol and stimulated sterol 27-hydroxylase and alternative bile acid synthesis, which expanded the bile acid pool and inhibited cholesterol 7 alpha-hydroxylase in rabbits. In distinction, hepatic sterol 27-hydroxylase was insensitive to changes in the bile acid pool.

Animals↗

PubMed1997

Using asymmetric jaws to junction with previously treated areas.

The feasibility of employing asymmetric jaws to match previously irradiated portals has been investigated. According to the isodose plot of one treatment planning system a near perfect match can be obtained by exactly matching the beam divergence of the initial port. However, another treatment planning system shows a cold junction. Films taken at 6 cm depth show a 6% cold spot when matching at the inferior border of the previously irradiated port and a 7% hot spot when matching at the superior border. As long as one is aware of the limitations of computer planning and collimator setting tolerance, junctioning with asymmetric jaws may still be preferred over the conventional method of gapping on the skin, because it avoids larger hot and cold spots below and above the matchpoint.

Computer Simulation↗

PubMed1997

Serodiagnosis of Helicobacter pylori infection: comparison and correlation between enzyme-linked immunosorbent assay and rapid serological test results.

CLOser is a new, one-step, qualitative anti-Helicobacter pylori immunoglobulin G test having the advantage of convenience and simplicity. We aimed to evaluate its diagnostic accuracy and to compare it with a quantitative enzyme-linked immunosorbent assay (ELISA) (HEL-pTEST II) in a study of 86 adult dyspeptic patients by using the results from histology and urease testing of gastric biopsies as a "gold standard." Forty-six patients were H. pylori positive. The sensitivities, specificities, and positive and negative predictive values were 95.7, 72.5, 80.0, and 93.5%, respectively, for CLOser and 93.5, 92.5, 93.5, and 92.5%, respectively, for HEL-pTEST II. The grade of the colored test bands in CLOser was correlated with antibody titers in HEL-pTEST II (r = 0.71; p < 0.001). The mean antibody titers were 13, 74, 186, and 328 U/ml for the negative, faint, thin, and thick bands, respectively, of CLOser. We concluded that the CLOser rapid serological test yielded sensitivity similar to that of the conventional ELISA. Although CLOser is not suitable for epidemiologic screening for H. pylori infection on account of lower specificity, it is particularly convenient and very easy to perform. Therefore, it may eventually become widely used in the office-based care of patients and lead to more cost-effective patient management decisions.

Adult↗

PubMed1997

Gastric emptying and gastrointestinal transit during lactation in rats.

Female sex hormones can influence gastrointestinal function. To understand whether postpartum changes in female sex hormones may affect such function, gastric emptying and gastrointestinal transit were measured in rats on days 1-2, 10, 15, and 21 of lactation, on day 7 postweaning, and at the nonpregnant diestrous stage. Gastric emptying and gastrointestinal transit were assessed in conscious rats 15 min after intragastric instillation of a test meal containing charcoal and (51)Cr. The results showed that gastric emptying was increased throughout the first 2 wk of lactation, with a gradual decrease as lactation proceeded toward weaning, and returned to the level of the virgin rats by 1 wk postweaning. Gastrointestinal transit was greater in the early stage of lactation and was related to gastric emptying (P < 0.001). Increases in gastric emptying and intestinal length were correlated with lactation (P < 0.001) and plasma prolactin levels (P < 0.05) but not with plasma progesterone or estradiol levels. We concluded that the sex steroid hormones associated with lactation do not mediate a change in gastric emptying and gastrointestinal transit during lactation.

Animals↗

PubMed1997

Application of automatic boundary detection for computerized quantitative analysis of left ventricular regional wall motion by two-dimensional echocardiography.

This study was designed to set up a computer-aided image processing algorithm for boundary detection from two-dimensional echocardiography and to establish a computerized model for quantitative analysis of left ventricular wall motion with the application of automatic boundary detection. The four-chamber view echocardiographic images of seven normal subjects and five patients with acute myocardial infarction were investigated. The main steps of image processing in this algorithm included automatic threshold estimation, contrast stretching, radial search of endocardial boundary, and smoothing of the boundary. The displacements of the left ventricular endocardial contour from end-diastolic to end-systolic frame were measured using a sample point connection model. For analysis of the regional contraction, the left ventricular endocardial contour was divided equally into six segments. The wall motion curves in patients were compared with the normal wall motion pattern established from the normal subjects to identify the segments with normal or abnormal wall motion. The results of this quantitative method were compared with those of qualitative analysis. In the 30 segments of the five patients, quantitative analysis correctly identified nine of the 11 segments with abnormal wall motion diagnosed by qualitative analysis (sensitivity, 82%) and identified 17 of the 19 segments with normal wall motion (specificity, 89%). The positive and negative predictive values of quantitative analysis were 82% (9 of 11) and 89% (17 of 19), respectively, and the diagnostic accuracy was 87% (26 of 30). Our preliminary results suggest that computer-aided boundary detection can be applied to establish an objective and useful model for quantitative analysis of left ventricular regional wall motion.

Adult↗

PubMed1997

Altered intestinal transit is independent of gastroparesis in the early diabetic rats.

The object of this trial was to study whether deranged intestinal transit in diabetic rats should be responsible for their gastroparesis. Male Sprague-Dawley rats received i.v. injection of streptozotocin 5 days before the motility experiment. Diabetic induction led to a marked body weight loss. The rats were sacrificed 15 min after the feeding of radiochromium and charcoal contained test marker. Then the radioactivity represented gastric emptying and charcoal represented intestinal transit were counted. Diabetic induction delayed gastric emptying as compared with controls (mean +/- SE: 41.0 +/- 2.5% vs. 57.1 +/- 3.5%, p < 0.001) while the intestinal transit was also inhibited (34.2 +/- 1.4% vs. 41.5 +/- 2.7%, p < 0.05). Diabetic gastric emptying values did not exhibit any correlation with intestinal transits but a correlation with plasma glucose levels was obtained (r = 0.522, p < 0.05). Gastric emptying values almost manifested a correlation with body weight ratios during the diabetic housing (r = 0.511, p = 0.0515). We conclude that hyperglycemia is one of the mechanisms to delay liquid gastric emptying but the latter is not chiefly resulted from the deranged intestinal transit. Dysmotility is probable one of factors enabled to impair the body weight gain.

Animals↗

PubMed1996

Selegiline is neuroprotective in primary brain cultures treated with 1-methyl-4-phenylpyridinium.

The ability of selegiline to protect against the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been attributed to the inhibition of the conversion of MPTP to 1-methyl-4-phenylpyridinium (MPP+), catalyzed by monoamine oxidase-B. Selegiline, however, has been found to rescue neurons in MPP(+)-treated mice after they have sustained lethal damage independently of monoamine oxidase-B inhibition. In our present study, we investigate whether selegiline can protect and/or rescue MPP(+)-injured dopaminergic neurons in co-cultures of mesencephalic and striatal cells of embryonic C57B1/6 mouse brains. Cells were exposed to selegiline (1, 10, 100 microM) in three different schemes: (i) in control cultures on the 8th day for 48 h; (ii) pretreatment: on the 8th day for 48 h, followed by administration of MPP+ (0.5 microM) on the 9th day for 24 h; (iii) delayed treatment: on the 9th day for 48 h, while MPP+ was administered on the 8th day and remained in culture during treatment with selegiline. In the delayed scheme, selegiline (1 microM) increased dopamine content, number of tyrosine hydroxylase immunoreactive cells and astrocytes in the cultures. We question whether selegiline protects cells injured by a toxic stressor via an astrocyte-mediated mechanism.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed1996

Blocking late cholesterol biosynthesis inhibits the growth of transplanted Morris hepatomas (7288CTC) in rats.

The conversion of 7-dehydrocholesterol to cholesterol is the last reaction in the cholesterol biosynthesis pathway catalyzed by the microsomal enzyme, 7-dehydrocholesterol-delta 7-reductase. We studied whether malignant tumor growth that depends on cholesterol could be slowed by inhibiting late cholesterol biosynthesis. The inhibitor 7-dehydrocholester-delta 7-reductase, BM 15.766 alone, or in combination with 2% cholesterol was fed to 20 male Buffalo rats for 2 weeks immediately after Morris hepatoma 7288CTC was implanted in both flanks. Tumor weights were compared and sterol composition, hepatic hydroxymethyl glutaryl coenzyme A (HMG-CoA) reductase activity, and low-density lipoprotein (LDL) receptor binding in the tumor were correlated with those in the liver. In the plasma of rats treated with BM 15.766, cholesterol levels dropped 75% and the precursor, 7-dehydrocholesterol rose substantially. Tumor weights were 43% less (P < .05) than controls (5.9 +/- 1.5 g vs. 10.4 +/- 2.2 g) with sterol concentrations reduced 25%, and the precursor, 7-dehydrocholesterol, increased to represent 71% of the tumor sterols. Feeding cholesterol with BM 15.766 normalized plasma but only partially restored tumor cholesterol concentrations, which still remained 49% below the hepatomas in the control group. With BM 15.766, hepatic cholesterol decreased 76% and was associated with a marked rise of 7-dehydrocholesterol that could be almost entirely prevented by feeding cholesterol. After the tumor was implanted, hepatic HMG-CoA reductase activity increased 56% and was 8.6 times higher than in the tumor. Enzyme activities were enhanced about 50% in the liver and the tumor after BM 15.766 was administered but decreased 38% below control when cholesterol was added to the diet. Hepatic receptor-mediated LDL binding rose 67% after tumor implantation, and declined to control levels with cholesterol feeding. These results suggest that de novo cholesterol synthesis in Morris hepatoma 7288CTC is much lower than the liver and tumor growth depends on circulating plasma cholesterol. Inhibiting the last step in cholesterol biosynthesis profoundly reduced tissue and plasma cholesterol concentrations and accumulated precursors substantially to slow hepatoma growth. Feeding cholesterol restored liver but not hepatoma cholesterol levels. Thus, inhibiting late cholesterol synthesis hinders growth of rapidly enlarging malignant tumors.

Animals↗

PubMed1996

Increasing hepatic cholesterol 7alpha-hydroxylase reduces plasma cholesterol concentrations in normocholesterolemic and hypercholesterolemic rabbits.

The effect of bile acid depletion and replacement with glycodeoxycholic acid on plasma cholesterol concentrations, hepatic low-density lipoprotein (LDL) receptor binding and messenger RNA (mRNA) levels, and hepatic activities and mRNA levels for 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and cholesterol 7alpha-hydroxylase was investigated in 19 New Zealand white (NZW) and 15 Watanabe heritable hyperlipidemic (WHHL) rabbits. Bile acid depletion was produced by external bile drainage for 5 days, which maximized cholic acid synthesis. Replacement was achieved by infusing glycodeoxycholic acid intraduodenally for 24 hours so that the hepatic bile acid flux reached prefistula levels. Plasma and liver cholesterol concentrations were 13 times and 50% greater, respectively, hepatic LDL receptor-mediated binding was 26% less, and cholesterol 7alpha-hydroxylase activity and mRNA levels were 62% and 86% less in WHHL than NZW rabbits. After bile drainage, plasma cholesterol concentrations decreased 29% in NZW rabbits and 40% in WHHL rabbits and were associated with a 2.1-fold increase in hepatic LDL receptor-mediated binding in the NZW rabbits, but there was no change in the WHHL rabbits. Cholesterol 7alpha-hydroxylase activity and mRNA levels increased three and four times in NZW and WHHL rabbits, respectively, although liver cholesterol levels remained unchanged. Replacement with exogenous glycodeoxycholic acid increased plasma cholesterol concentrations 1.7 times in NZW rabbits and decreased enhanced cholesterol 7alpha-hydroxylase activity 54%, mRNA levels 86%, cholic acid synthesis 38%, and hepatic LDL receptor-mediated binding 57% in NZW rabbits. Bile acid depletion stimulated cholic acid synthesis by up-regulating cholesterol 7alpha-hydroxylase to use cholesterol and reduce plasma concentrations substantially in both NZW and WHHL rabbits, although LDL receptors did not function in WHHL rabbits. Glycodeoxycholic acid replacement inhibited elevated cholesterol 7alpha-hydroxylase, cholic acid synthesis, and hepatic LDL receptor binding to reestablish baseline plasma cholesterol levels in NZW rabbits. Hypercholesterolemia in WHHL rabbits was related to the combination of dysfunctional LDL receptors and inhibited cholesterol 7alpha-hydroxylase. Plasma cholesterol concentrations were reduced significantly when cholesterol 7alpha-hydroxylase was stimulated even in the absence of LDL receptor function.

Animals↗

PubMed1996

Use of near-infrared spectroscopy to evaluate an active in a film coated tablet.

PURPOSE: To provide a method to rapidly screen tablets in the development of new coating technology. METHODS: Near-Infrared (NIR) reflectance spectroscopy was used to quantitatively analyze tablets which were composed of a drug active encasing an active drug core. Diffuse reflectance NIR scans of 240 individual tablets over the range of 1100-2500 nm were obtained. High Performance Liquid Chromatography (HPLC) was used as the reference method. RESULTS: Both qualitative, Principal Component Analysis, and quantitative results showed a strong agreement between the NIR and HPLC methods. The NIR analysis was non-invasive and allowed subsequent testing of the tablets. The contents of the drug active contained in a drug coating was determined to +/- 4% of the target value using NIR analysis. Over 400 samples were analyzed in less than a month utilizing this technique which allowed the optimization of a new coating technology. CONCLUSIONS: NIR analysis allowed the evaluation of the efficiency of a new drug film coating manufacturing process more quickly and inexpensively. Because the Near-Infrared method was non-invasive the tablets were available for further analysis unlike the chromatography method.

Calibration↗

PubMed1996

Adaptations of ligamentum teres in ischemic necrosis of human femoral head.

Little is known about the biomechanical properties of human ligamentum teres. To more fully understand the ligamentum teres, its dimensions and mechanical properties were measured in 22 cases of acute fracture of the femoral neck and 21 cases of ischemic necrosis of the femoral head. The specimens first were preconditioned and then loaded to failure with a testing machine at a fast strain rate of 100% s(-1). The ischemic necrosis group had a significantly larger volume (3.09 +/- 1.81 ml versus 1.30 +/- 0.62 ml) and cross section area (65.3 +/- 59.1 mm2 versus 30.6 +/- 27.2 mm2) than did the acute fracture group. The former also had a significantly greater ultimate load (234 +/- 168 N versus 130 +/- 111 N) and strain energy to failure (1.22 +/- 1.04 J versus 0.41 +/- 0.39 J), but a significantly smaller linear modulus (4.72 +/- 3.31 MPa versus 8.69 +/- 7.97 MPa) than did the latter. Histologic studies showed differences in the amount of organized collagen and components of subsynovial tissue between the 2 groups. Mechanical and morphologic adaptations of the ligamentum teres in a group of ischemic femoral heads are described, and a possible biomechanical role is suggested for the ligamentum teres in the hip joint in conjunction with the ischemic necrosis of the femoral head.

Adaptation, Physiological↗

PubMed1996

Morgagni: his book, vision and views on hepatic coma.

The study of pathological anatomy reached a culmination in the magnum opus of Morgagni, The Seats and Causes of Diseases. It represented an innovative way of looking at the patient and his illness, a change that Foucault described as occurring in the 18th century. Physicians saw symptoms penetrating the body and converging upon an organ. We suggest that Morgagni and his fellow workers derived their vision from the practice of visual perspective discovered by Italian Renaissance artists. Perceiving in three dimensional terms, Morgagni added spatial depth to our understanding of disease. His acute vision was brilliantly displayed in his views of hepatic coma. He was among the first to provide the clinical-pathological associations of acute liver failure. The limitations of gross morphology precluded a complete elucidation of the disorder.

Europe↗

PubMed1996

Patellar dislocation after total knee arthroplasty.

BACKGROUND: Patellar problem is an important cause of nonseptic failure of the current condylar design of total knee arthroplasties. Patellar dislocation after total knee arthroplasty is infrequent but can cause disabling symptoms. METHODS: From March, '84 to July, '92, 1652 total knee arthroplasties were performed at this Hospital. Of these 1100 knees in 978 patients were available to be followed up regularly at the Outpatient Department. Eleven cases of patellar dislocation after total knee arthroplasty were encountered during follow-up. Among these patients, nine patients had received operation at this Hospital; the other two patients had been referred here by the other hospitals. All 11 patients had been treated with surgical methods: proximal realignment of the quadriceps alone in 6 knees, lateral retinacular release combined with revision of the malaligned components in 2 knees, combined proximal and distal realignment in 2 knees and patellar tendon transfer in 1 knee. RESULTS: After an average follow-up of 21.8 months, from April, '84 to April, '93, there was one redislocation, unfortunately caused by trauma. Using the average knee rating scale of the Hospital for Special Surgery, New York, USA, the results of 90.5 were satisfactory and encouraging. CONCLUSIONS: Patellar dislocation after total knee arthroplasty can cause disabling symptoms, including pain, weakness, limited range of motion, extension lag and difficulty when climbing up or down stairs. The cause of patellar dislocation after total knee arthroplasty was error in surgical technique in this series. Revision of the component should be performed in those with malaligned component. Proximal realignment is recommended in those with quadriceps imbalance. Distal realignment is recommended only when proximal realignment alone has failed to restore proper patellar tracking, this should be carried out with great caution due to the potential for serious complications.

Aged↗