Search PubMed⌕ Search

Biomedical subjects

C C Chu

Publications and source records attributed to C C Chu.

At least 73 records · Page 4Linked to original sources
PubMed1998

Anesthetic management of a parturient with Eisenmenger's syndrome and preeclampsia during cesarean section--a case report.

It has been recommended that women with Eisenmenger's syndrome (ES) are better not to become pregnant and pregnancy may justifiably be terminated by artificial abortion to avoid high maternal mortality and coherent fetal mortality. We present a case report about a parturient with ventricular septal defect (VSD) and ES who received general anesthesia for Cesarean section (C/S) because of preeclampsia, as a result of which she finally succumbed to an episode of intraoperative hypotension in spite of vigorous cardiopulmonary resuscitation. The death was thought to be precipitated by continuous deterioration of maternal health during the 3rd trimester of gestation. The anesthetic management of pregnant ES patients in confinement was reviewed and discussed, and the possible etiological factors relevant to the tragic outcome were also explored.

Adult↗
PubMed1997

Fiber-matrix interface studies on bioabsorbable composite materials for internal fixation of bone fractures. II. A new method using laser scanning confocal microscopy.

In this study, a new visual characterization method was developed using laser scanning confocal microscopy (LSCM) to study morphologic properties, particularly at the fiber-matrix interface, by optical sectioning of bioabsorbable single-fiber composites. The interface gap width (IGW) between the fiber and matrix, and the changes in IGW after in vitro hydrolysis, named the gap rate (Rg), were measured from images obtained using the LSCM. Higher values for IGW and Rg showed faster degradation of the fiber-matrix interface. These parameters were used to investigate the effects of strain, wicking, different reinforcing fibers, and gamma-irradiation on the fiber-matrix interface morphology. The component materials used were nonbioabsorbable AS4 carbon (C) fibers, bioabsorbable calcium phosphate (CaP), poly(glycolic acid) (PGA), and chitin fibers, and bioabsorbable poly(L-lactic acid) (PLLA) matrix. The application of strain on CaP/PLLA composites increased the IGW up to about 15%, after which there was no change up to 25%. The Rg for CaP/PLLA composites with the fiber ends exposed in vitro (permitting wicking) was greater than for CaP/PLLA with the fiber ends embedded completely within the matrix (preventing wicking). Open-end C/PLLA composites had the slowest rate of interface degradation in vitro, followed by chitin/PLLA, PGA/PLLA, and CaP/PLLA. The exposure of closed-end CaP/PLLA composites to 4 Mrad of gamma-irradiation, in air at room temperature or in vaccuum at 77K, accelerated the rate of interface degradation in vitro. In conclusion, an effective new visual characterization method was developed using LSCM, and it was used to show that (a) moderate strain could accelerate the degradation of the interface, (b) fiber-matrix interface wicking could accelerate the rate of degradation of the interface, (c) the rate of interface degradation depends on the type of fiber used, and (d) gamma-irradiation could accelerate the rate of interface degradation. Furthermore, the results of LSCM analysis of different reinforcing fibers with a PLLA matrix agree with measurements of interfacial shear strength (IFSS) and single-fiber tensile strength reported in Part I of this study.

Chitin↗
PubMed1997

Fiber-matrix interface studies on bioabsorbable composite materials for internal fixation of bone fractures. I. Raw material evaluation and measurement of fiber-matrix interfacial adhesion.

The objective of this study was to characterize and evaluate the performance of various fiber-matrix composite systems by studying the mechanical, thermal, and physical properties of the fiber and matrix components, and by studying the fiber-matrix interface adhesion strength using both microbond and fragmentation methods. The composites studies were poly(L-lactic acid) (PLLA) matrix reinforced with continuous fibers of either nonabsorbable AS4 carbon (C), absorbable calcium phosphate (CaP), poly(glycolic acid) (PGA), or chitin. Carbon and CaP single fibers had high Young's moduli and failed in a brittle manner. PGA and chitin single fibers had relatively lower Young's moduli and relatively higher ductility. Upon in vitro hydrolysis, CaP fibers retained 17% of their tensile strength and 39% of their Young's modulus after 12 h, PCA fibers retained 10% of their tensile strength and 52% of their Young's modulus after 16 days, and chitin fibers retained 87% of their tensile strength and 130% of their Young's modulus after 25 days. PLLA films had much lower strength and Young's moduli, but much higher ductility relative to the single fibers. Using the microbond method, the initial fiber-matrix interfacial shear strength (IFSS) of C/PLLA and CaP/PLLA microcomposites was 33.9 and 12.6 MPa, respectively. Upon in vitro hydrolysis, C/PLLA retained 49% of IFSS after 15 days and CaP/PLLA retained 46% of IFSS after 6 h. Using a fiber fragmentation method, the initial IFSS of C/PLLA, CaP/PLLA, and chitin/ PLLA was 22.2, 15.6, and 28.3 MPa, respectively. The performance of carbon fibers and C/PLLA composites was superior to the other fibers and fiber/PLLA systems, but the carbon fiber was nonabsorbable. CaP had the most suitable modulus of the absorbable fibers for fixing cortical bone fracture, but its rapid deterioration of mechanical properties and loss of IFSS limits its use. PGA and chitin fibers had suitable mechanical properties and their retention for fixing cancellous bone fractures, but likely had insufficient stiffness for applications such as bone plates for fixing cortical bone fractures.

Adhesiveness↗
PubMed1997

Fig1, an interleukin 4-induced mouse B cell gene isolated by cDNA representational difference analysis.

Interleukin 4 (IL-4) is a cytokine that regulates growth and differentiation of lymphoid and nonlymphoid cells. To study the molecular basis of IL-4 function, we used a cDNA subtraction approach based on the representational difference analysis method. This subtractive amplification technique allowed us to use small amounts of RNA from lipopolysaccharide +/- IL-4-stimulated normal B cells to obtain IL-4-induced genes from these cells. We report here on one such gene, Fig1 (interleukin-four induced gene 1), the first characterized immediate-early IL-4 inducible gene from B cells. Fig1 expression is strikingly limited to the lymphoid compartment. B cells, but not T cells or mast cells, express Fig1 in response to IL-4 within 2 hr in a cycloheximide resistant manner. IL-2, IL-5, and I1-6 do not induce Fig1 in culture. Fig1 maps between Klk1 and Ldh3 on mouse chromosome 7, near two loci involved with murine lupus, Sle3 and Lbw5. The Fig1 cDNA sequence encodes a predicted 70-kDa flavoprotein with best homology to the monoamine oxidases, particularly in domains responsible for FAD binding.

Animals↗
PubMed1997

Exaggerated luminal loss a few minutes after successful percutaneous transluminal coronary angioplasty in patients with recent myocardial infarction compared with stable angina: an intracoronary ultrasound study.

This study investigates the mechanisms of exaggerated acute luminal loss after successful coronary angioplasty in patients with recent myocardial infarction compared with stable angina by angiography and intracoronary ultrasound (ICUS). We studied 15 consecutive patients (group 1) who, after a successful thrombolysis for myocardial infarction, underwent delayed (8 +/- 2 days after the myocardial infarction) successful balloon coronary angioplasty. Group 1 patients were individually matched with 15 stable angina patients (group 2). The percentage of stenosis and acute luminal loss were measured by quantitative coronary analysis. The ultrasound characteristics of lumen pathology were described as soft, hard, calcified, eccentric, concentric, thrombotic, and dissection lesions. Matching by stenosis location, reference diameter, sex, and age resulted in 2 comparable groups of 15 lesions with identical baseline characteristics. Immediately after percutaneous transluminal coronary angioplasty (PTCA), the minimal luminal diameter increased from 0.5 +/- 0.3 mm to 2.4 +/- 0.3 mm and from 0.5 +/- 0.2 mm to 2.4 +/- 0.3 mm in groups 1 and 2, respectively. Similar balloon sizes were used in both groups. The acute luminal loss (the difference between the maximal dilated balloon diameter and the minimal luminal diameter) immediately after PTCA was 0.4 +/- 0.2 mm and 0.3 +/- 0.3 mm (14 +/- 8% and 10 +/- 11% of balloon size) (P = not significant [NS]) in groups 1 and 2, respectively. After ICUS (mean 24 min after the last balloon deflation), the acute luminal loss was 0.9 +/- 0.3 mm and 0.5 +/- 0.4 mm (29 +/- 11% and 17 +/- 8% of balloon size) (P = 0.01) in groups 1 and 2, respectively. There was a significantly higher prevalence of intracoronary thrombus formation as detected by ICUS in group 1 compared with group 2 (80% vs. 20%; P < 0.001). In matched groups of successfully treated coronary angioplasty, patients with recent myocardial infarction had a similar magnitude of acute gained luminal loss immediately after the procedure. However, an exaggerated luminal loss a few minutes after the last balloon deflation in patients with recent myocardial infarction was noted because of mural thrombus formation compared with patients with stable angina.

Aged↗
PubMed1997

Peripheral neuropathy in mitochondrial encephalomyopathies.

Seven patients with mitochondrial encephalomyopathies were studied for peripheral neuropathy by clinical, electrophysiological and pathological examinations. The clinical manifestation of neuropathy varied from asymptomatic to mild and moderate sensorimotor symptoms with painful paresthesia. Five patients (2 with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes, and 3 with myoclonic epilepsy and ragged-red fibers, MERRF) had clinical symptoms and signs of polyneuropathy associated mainly with decreased amplitudes of the compound muscle or nerve action potentials in an electrophysiological study indicating axonal degeneration. Sural nerve biopsy from 1 MERRF patient, also confirmed an axonal degeneration with reduction of large myelinated fibers. Mitochondrial DNA analysis of the sural nerve from this patient showed a point mutation from A to G transition at the nucleotide position 8344 with 80% mtDNA mutation. The results of this study suggest that peripheral neuropathy is not uncommon in mitochondrial encephalomyopathies and is predominantly due to axonal degeneration.

Adolescent↗
PubMed1997

Carotid floating plaques associated with multiple cerebral embolic strokes. Case reports.

The authors describe 2 patients with multiple cerebral infarcts and hemorrhagic transformation caused by artery-to-artery emboli. Ulcerated plaques with free-floating thrombus adherent to the plaque were detected at the carotid bifurcation by duplex sonography. No other embolic source could be found. One patient developed an occipital infarction due to carotid emboli passing through a fetal-type posterior communicating artery. Both patients recovered well without recurrence of stroke or transient ischemic attack with antiplatelet treatment only. Follow-up carotid duplex sonography showed disappearance of floating thrombus in 1 patient and consolidation of the lesion in the other.

Adult↗
PubMed1997

Cerebral sparganosis: increased uptake of technetium-99m-HMPAO.

Cerebral sparganosis is an extremely rare intracranial parasitic infectious disease. We report findings of 99mTc-HMPAO cerebral perfusion SPECT in a case with cerebral sparganosis. SPECT revealed an irregularly shaped area with markedly increased 99mTc-HMPAO uptake in the parasitic infectious region of the cerebrum. Both white and gray matter was involved, the white matter involved predominantly. Decreased perfusion to the right cerebellum, suggesting cross cerebellar diaschisis, was also demonstrated. This article illustrates that cerebral sparganosis is one of the causes of increased 99mTc-HMPAO uptake in the cerebrum and should be considered clinically if present.

Aged↗
PubMed1997

The lost endotracheal tube--a rare complication of accidental esophageal intubation.

Endotracheal intubation is a discreet skill for the management of compromised airway. Various complications associated with this procedure have been described. Here, we would like to present a pediatric patient suffering from cerebellar atrophy, who was intubated in a local clinic due to seizure with cyanosis and loss of consciousness. Unfortunately, due to inadvertent esophageal intubation and bad management, the patient swallowed the endotracheal tube together with two detached loose teeth. This irrational and iatrogenic medical misconduct as exemplified in this accident calls forth the need of educating and disciplining the nonanesthetic physicians for acute management of airway, particularly of those who would likely come across difficult airway problems.

Child, Preschool↗
PubMed1996

H-protein of the glycine cleavage system in Flaveria: alternative splicing of the pre-mRNA occurs exclusively in advanced C4 species of the genus.

A recent paper reports on the occurrence of alternative splicing of H-protein pre-mRNA in the C4 species, Flaveria trinervia, that is organ-specifically regulated. The analysis of 11 other species of the genus, F. cronquistii and F. pringlei (C3), F. anomala, F. chloraefolia, F. floridana, F. linearis and F. pubescens (C3-C4 intermediate), F. brownii (C4-like), F. palmeri, F. bidentis and F. australasica (C4), revealed that this post-transcriptional effect is not specific for F. trinervia. It occurs in all the examined C4 species of the genus Flaveria except the less advanced C4-like species, F. brownii. Both the position and the direct effect of alternative splicing, the addition of two alanine residues near to the N-terminus of the derived mature H-protein, are invariant. A quantification of the relative amounts of both transcripts revealed that, as in F. trinervia, the alternative mRNA strongly dominates in leaves. In sharp contrast, none of the C3, C3-C4 intermediate, or C4-like species showed alternative splicing. By Western analysis both H-isoproteins have been detected in F. trinervia and their ratio approximately corresponds to the measured transcript levels. It is concluded that alternative splicing leads to the synthesis of two different H-proteins of the glycine cleavage system in all advanced Flaveria C4 species.

Alternative Splicing↗
PubMed1996

Carbon disulfide induced polyneuropathy: sural nerve pathology, electrophysiology, and clinical correlation.

We report the clinical features, electrophysiological studies, sural nerve pathology and recovery course of carbon disulfide-(CS2) induced polyneuropathy in a 48-year-old man who worked in a viscose rayon plant. Sural nerve biopsy 2 years later still showed degeneration of both axon and myelin with a predominant loss of large myelinated fibers and remyelination. Electrophysiologic studies revealed mixed axonal and demyelinating polyneuropathy. To our knowledge, this is the first human report of sural nerve pathology in the recovery stage due to CS2 intoxication. After diagnosis, the patient was removed from the toxic environment. In the following three years, he showed part recovery predominantly in motor function compatible with the serial nerve conduction studies. We conclude that CS2 polyneuropathy may partly recover years after cessation of exposure.

Axons↗
PubMed1996

Inguinal hernia in children: US versus exploratory surgery and intraoperative contralateral laparoscopy.

PURPOSE: To analyze the value of ultrasound (US) in the preoperative recognition of clinically apparent and inapparent inguinal hernias (or patent processus vaginalis). MATERIALS AND METHODS: Two hundred sixty children (197 boys, 63 girls), in whom a clinical diagnosis of inguinal hernia (226 unilateral hernias, 34 bilateral hernias) had been made, underwent US examination with a 7.0-MHz linear-array transducer. The contralateral internal inguinal ring was evaluated by means of intraoperative laparoscopy in 141 patients. The 197 boys were grouped together by age (< 12 months, 12-24 months, 24-48 months, 48-72 months, and > 72 months). RESULTS: In the 260 patients who underwent inguinal herniorrhaphy, 246 hernias (95%) were correctly diagnosed at US based on criteria of an internal inguinal ring width greater than 4 mm in diameter or the presence of fluid or organs in the inguinal canal at rest or during straining. A total of 473 hernias were confirmed surgically and 459 (97%) hernias were correctly detected at US. A statistically significant difference in the mean width of the internal inguinal ring of the five age groups was found between patients at rest and during straining (P < .05) in US measurement of the 197 surgically proved cases in boys. CONCLUSION: US is a noninvasive, readily available, and highly accurate (95%) method for evaluating the presence of inguinal hernia in children at risk, especially when the clinical findings are equivocal or normal. US can provide an objective measure in determining the advisability of exploratory inguinal surgery in such cases.

Adolescent↗
PubMed1996

Chronic carbon disulfide encephalopathy.

To understand central nervous damage after long-term exposure to carbon disulfide (CS2), 10 patients who had polyneuropathy with various neuropsychiatric symptoms in a viscose rayon plant were studied. Clinical and laboratory examinations including electroencephalography (EEG), brain computed tomography (CT), brain magnetic resonance images (MRI), and carotid duplex sonography were carried out. Clinically, headache, unpleasant dreams, memory impairment, fatigue, anorexia and emotional lability were common in these patients while 2 patients had stroke episodes. EEGs were all normal. Brain CT scan showed mild cortical atrophy in 3 and low density lesions in the basal ganglia in 3. Brain MRI studies also disclosed mild cortical atrophy in 4 and multiple lesions involving the basal ganglia and corona radiata in 4. Carotid duplex sonography revealed mild atherosclerosis with plaques (< 20% stenosis) of extracranial vessels in 6. However there was no significant difference in flow velocities and flow volumes in the extracranial carotid arteries between patients and the normal controls. Interestingly, 2 patients had multiple brain lesions in the subcortical white matter but without strokes. In conclusion, encephalopathy with possible strokes may occur after chronic exposure to CS2, as well as polyneuropathy. The lesions usually involve the basal ganglia and subcortical white matter. Furthermore, MRI study may detect brain lesions particularly in the subcortical white matter areas before the occurrence of stroke.

Brain Diseases↗
PubMed1996

Recurrent hypokalemic muscle weakness as an initial manifestation of Wilson's disease.

A 24-year-old man had several episodes of hypokalemic muscle weakness of undetermined etiology since the age of 13 years. Wilson's disease (WD) was not diagnosed until the age of 18 when wing-beating tremor in the left upper limb was noted. Renal function study revealed incomplete proximal renal tubular acidosis. The hypokalemic muscle weakness and wing-beating tremor had subsided after long-term penicillamine therapy. The present case indicates that recurrent hypokalemic paralysis due to renal tubular acidosis is a rare initial presentation of WD and may respond to penicillamine therapy.

Acidosis, Renal Tubular↗
PubMed1996

Case report: Pontine haemorrhage following iohexol lumbar myelography.

A case of pontine haemorrhage following lumbar myelography using iohexol is described. Stress, inducing transient hypertension during the procedure, with superimposed neurotoxicity from contrast medium (iohexol) is suggested as a possible mechanism. No brain stem lesion was seen on the initial brain CT scan, possibly because of the high attenuation of the contrast medium in the subarachnoid space. A delayed CT brain scan demonstrated the pontine haemorrhage and was necessary to confirm the diagnosis.

Cerebral Hemorrhage↗
PubMed1996

Low-dose intravenous immunoglobulin therapy in myasthenia gravis: a case report.

The maintenance effect of low dose, short duration intravenous immunoglobulin (IVIg) therapy (0.3gm/kg/day for one day) is reported in a patient with myasthenia gravis. The patient had had a progressive course of diplopia, generalized muscle weakness and bulbar symptoms in spite of anticholinesterase agents and steroid therapy for two years. She received a course of high-dose IVIg infusion (0.5 gm/kg/day) for five days, and the symptoms disappeared in few days. However, they recurred 13 months later. Because of the high cost of high-dose IVIg, a trial with 0.3 gm/kg/day IVIg for 1 day was initiated. The clinical neurological manifestations improved within a few hours, and this made natural fluctuation unlikely. She received 4 courses of 1 day, low-dose IVIg therapy during the follow-up period of two years. The beneficial effects usually maintained for two to six months. She was symptom free and had no side effects. The report suggests that low-dose IVIg can be an alternative way, at least in some patients when there is consideration of economic benefit and convenience, compared with high-dose IVIg in the treatment of myasthenia gravis.

Adult↗