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Biomedical subjects

Y Y Chang

Publications and source records attributed to Y Y Chang.

At least 73 records · Page 4Linked to original sources
PubMed1994

Unilateral cheiro-oral syndrome in a patient with bilateral subdural hematomas.

We report a 49-year-old man with acute intermittent perioral and distal hand sensory dysfunction on the left side (cheiro-oral syndrome). The responsible lesion was confirmed by magnetic resonance imaging to be bilateral subdural hematomas with the larger side compressing the middle and lower thirds of the right postcentral gyrus. We emphasize that subdural hematoma should be considered in the differential diagnosis of cheiro-oral syndrome.

Diagnosis, Differential↗
PubMed1994

Low dose propranolol-induced delirium: 3 cases report and a review of literature.

Delirium in 3 elderly patients with recent cerebral infarction and pre-existing brain dysfunction receiving low dose propranolol is described. The dose ranged from 30 to 60 mg/day and the interval between delirium onset and drug initiation was 3-7 days. One patient exhibited ictal mydriasis and sinus tachycardia. Hypoalbuminemia was found in 1 patient. Discontinuation of propranolol abolished their delirious pictures 2-5 days later. Their delirium may be attributed to central beta blockade or anticholinergic effect. Preexisting brain damage, old age and hypoalbuminemia may predispose such patients to neuropharmacotoxicity of low dose propranolol.

Aged↗
PubMed1993

Molecular cloning, DNA sequencing, and biochemical analyses of Escherichia coli glyoxylate carboligase. An enzyme of the acetohydroxy acid synthase-pyruvate oxidase family.

Glyoxylate carboligase (Gcl) (EC 4.1.1.47) of Escherichia coli catalyzes the condensation of two molecules of glyoxylate to give tartronic semialdehyde, a key intermediate in glyoxylate catabolism. We report the cloning, genomic location, and DNA sequence of the gene (called gcl) encoding E. coli Gcl and isolation of mutants lacking the enzyme. Gcl is a protein of 593 amino acid residues (64,738 Da) that has a high level (30%) of sequence similarity to the acetohydroxy acid synthases (AHAS) of branched chain amino acid synthetic pathway. Significant sequence identity (26%) was also observed with E. coli pyruvate oxidase, a redox flavoprotein, previously shown to be related to the AHAS enzymes (Chang, Y.-Y., and Cronan, J. E., Jr. (1988) J. Bacteriol. 170, 3937-3945). Consistent with a grouping of Gcl with the AHAS and pyruvate oxidase enzymes. Gcl contains a quinone binding site as well as binding site for thiamine pyrophosphate and FAD. We also found that a gene (orf258) immediately downstream of the gcl gene encoded a protein (Orf258) of 258 residues. Although the gene organization of gcl and orf258 is analogous to that of the ilv gene operons which encode the E. coli AHAS isozyme large and small subunits, Orf258 does not function as a Gcl subunit. Moreover, disruption of the chromosomal copy of orf258 did not affect growth on glyoxylate or glycolate.

Acetolactate Synthase↗
PubMed1993

Intractable hiccup caused by medulla oblongata lesions.

Intractable hiccup is a rare manifestation of a brainstem lesion. We present five cases of intractable hiccups associated with medulla oblongata lesions: three of these had brainstem infarction compatible with Wallenberg's lateral medullary syndrome; one, clinically probable multiple sclerosis with a medullary lesion; and one, choroid plexus papilloma of the fourth ventricle with medullary compression. Using magnetic resonance imaging, it was demonstrated that the lesions affecting the dorsal and/or lateral medulla oblongata were responsible for the intractable hiccups.

Adult↗
PubMed1993

Removal of renal cell carcinoma extending into the right atrium using cardiopulmonary bypass, profound hypothermia and circulatory arrest.

A 65-year-old man presented with renal cell carcinoma of the right kidney with a tumor thrombus extending up the vena cava to the right atrium. Cardiopulmonary bypass, profound hypothermia and total circulatory arrest were used to create a bloodless field for excision of the renal cell carcinoma and its tumor thrombus. Acute respiratory failure and deep jaundice developed after the operation and the patient was transferred to the intensive care unit for critical care. After respiratory therapy and nutritional support, the liver function was restored. The endotracheal tube was weaned one month later. The patient has had total resolution of all symptoms and there is no evidence of tumor recurrence of distant metastases after 6 months follow-up.

Aged↗
PubMed1993

Babinski-Nageotte syndrome: a case report.

A 68-year-old man developed a sudden onset of the left Wallenberg's syndrome with additional left hypoglossal nerve palsy and contralateral hemiparesis sparing the face. The clinical constellation, known as Babinski-Nageotte syndrome, is regarded as a combination of the medial and lateral medullary syndrome. Magnetic resonance imaging showed potential of in vivo confirmation of the underlying vascular insult, which clearly demonstrated an infarct area in the left half of the medulla oblongata.

Aged↗
PubMed1993

Two independent intracranial arteriovenous malformations: a case report.

Two independent intracranial arteriovenous malformations occurring to a single patient is rarely seen. A 23-year-old female suffered from a sudden onset weakness of the left side extremities and a generalized tonic-clonic seizure. A cranial CT revealed an intracranial hemorrhage in the right posterior temporal region and a highly enhanced mass in the left frontal lobe. On MR images, combination of subacute hematoma and serpentine vascular shadows in the right temporal area as well as clusters of vessels in the left frontal lobe were seen. Cerebral angiography confirmed one AVM in the right posterior temporal and the other the left frontal cortex.

Adult↗
PubMed1993

Metastatic brain tumor manifesting as lacunar syndrome in adults.

Lacunar syndrome can be an initial manifestation of the metastatic brain tumor in young adults. Two patients were encountered with previously undiagnosed lung cancer, one with anaplastic carcinoma and the other with adenocarcinoma. A neurologic syndrome occurred in the morning with unusual headache and stroke-like episodes, presenting an acute ataxic hemiparesis and a pure motor hemiparesis, respectively. Papilloedema was a universal finding. The headache and neurologic deficits responded rapidly to glucocorticoid. A preexisting intracranial mass with an outburst of brain edema is thought to be the mechanism in this situation.

Adult↗
PubMed1993

Extracranial internal carotid artery dissection secondary to neck massage: visualization of mural hematoma by MRI.

A 52-year-old man was admitted due to a severe pain in the right side of the neck and a progressive weakness of the left-side extremities. One week prior to admission, the patient began to use massage balls to relieve his long-lasting nuchal soreness. Carotid arteriography revealed a segment of tapered stenosis of the extracranial internal carotid artery with distal occlusion at the proximal middle cerebral artery. Magnetic resonance imaging (MRI) demonstrated a well-defined mural hematoma which is a distinctive feature of arterial dissection.

Carotid Artery Diseases↗
PubMed1993

Unilateral symptomatic palatal myoclonus: MRI evidence of contralateral inferior olivary lesion.

Symptomatic palatal myoclonus is a rare syndrome of segmental myoclonus which is thought to occur after damage to certain brainstem or cerebellar structures. We report two patients with unilateral PM, who showed hypertrophy of the inferior olivary nucleus on magnetic resonance imaging. In the first patient this was due to a left pontine tegmental hemorrhage, and a right-sided oculo-palato-facial myoclonus developed one month after the episode. The second one had a basilar artery occlusion with ischemic infarcts at the basis pontis, dorso-lateral aspects of the left pons, and left cerebellar dentate nucleus, as well as the occipital lobe. A delayed left oculopalatal myoclonus was recognized 3 months later. Interruption of the "dentato-rubro-olivary pathway" by the lesion with ensuing neuronal loss, cytoplasmic vacuolation, and astrocytic proliferation in the inferior olive, together with an increase of water content as mobile proton may cause the MR signal abnormalities in patients with unilateral symptomatic palatal myoclonus.

Aged↗
PubMed1992

[Low social economic status family and child maltreatment].

The purpose of the present research was to develop child abuse potential inventories as a screening tool. The sample was 248 families who were all financially supported by Chinese Children's Fund. Kaohsiung Family Helper. One of the inventories selected, that was translated into Chinese by the expert committee, was the Child Abuse Potential Inventory developed by Milner. The internal consistency and test-retest reliabilities obtained by this research were as good as Milner's and basic interpretation of four factors was found to be was consistent with Milner's data. The other inventory developed by the expert committee was the Child Abuse Potential Interview used by social workers to interview caretakers. Having completed the questionnaire social workers rated 15 items, i.e. immaturity, lack of parenting skills, unrealistic expectancy, social isolation, unresolved affective needs, abused experiences, crisis, substance abuse etc. The coefficients of correlation between these two inventories were 0.20-0.37, respectively, which indicated that these inventories assessed abuse potential trait and uniqueness. Therefore, these inventories were considered both highly applicable.

Adolescent↗
PubMed1992

[A study about the desirable characteristics of the qualified physicians: the application of Delphi method].

The purpose of this study is to adapt the Delphi Study method in establishing a consensus of good doctor characteristics from a panel of department heads (N = 22) at four medical colleges in Taiwan within three given categories: 1. professional knowledge and techniques; 2. attitudes and standards; and 3. interpersonal relationship. In this study three rounds of questionnaires were administered to the panel to extract their opinions regarding the characteristics of good doctoring. 76 items of good doctoring characteristics were solicited from the department heads at four medical colleges to the opening questionnaire. The conclusive results indicated that 15 of these 58 items were ranked as the most important characteristics by panel members. The findings from this investigation will help facilitate the decision making process of officials regarding innovation in the training of good doctor. Moreover, the conclusions could be included in developing and planning of instruments for the future doctor evaluation methods.

Clinical Competence↗
PubMed1991

Insertion of the mannitol permease into the membrane of Escherichia coli. Possible involvement of an N-terminal amphiphilic sequence.

The in vivo membrane assembly of the mannitol permease, the mannitol Enzyme II (IImtl) of the Escherichia coli phosphotransferase system, has been studied employing molecular genetic approaches. Removal of the N-terminal amphiphilic leader of the permease and replacement with a short hydrophobic sequence resulted in an inactive protein unable to transport mannitol into the cell or catalyze either phosphoenol-pyruvate-dependent or mannitol 1-phosphate-dependent mannitol phosphorylation in vitro. The altered protein (68 kDa) was quantitatively cleaved by an endogenous protease to a membrane-associated 39-kDa fragment and a soluble 28-kDa fragment as revealed by Western blot analyses. Overproduction of the wild-type plasmid-encoded protein also led to cleavage, but repression of the synthesis of the plasmid-encoded enzyme by inclusion of glucose in the growth medium prevented cleavage. Several mtlA-phoA gene fusions encoding fused proteins with N-terminal regions derived from the mannitol permease and C-terminal regions derived from the mature portion of alkaline phosphatase were constructed. In the first fusion protein, F13, the N-terminal 13-aminoacyl residue amphiphilic leader sequence of the mannitol permease replaced the hydrophobic leader sequence of alkaline phosphatase. The resultant fusion protein was inefficiently translocated across the cytoplasmic membrane and became peripherally associated with both the inner and outer membranes, presumably via the noncleavable N-terminal amphiphilic sequence. The second fusion protein, F53, in which the N-terminal 53 residues of the mannitol permease were fused to alkaline phosphatase, was efficiently translocated across the cytoplasmic membrane and was largely found anchored to the inner membrane with the catalytic domain of alkaline phosphatase facing the periplasm. This 53-aminoacyl residue sequence included the amphiphilic leader sequence and a single hydrophobic, potentially transmembrane, segment. Analyses of other MtlA-PhoA fusion proteins led to the suggestion that internal amphiphilic segments may function to facilitate initiation of polypeptide trans-membrane translocation. The dependence of IImtl insertion on the N-terminal amphiphilic leader sequence was substantiated employing site-specific mutagenesis. The N-terminal sequence of the native permease is Met-Ser-Ser-Asp-Ile-Lys-Ile-Lys-Val-Gln-Ser-Phe-Gly.... The following point mutants were isolated, sequenced, and examined regarding the effects of the mutations on insertion of IImtl into the membrane: 1) S3P; 2) D4P; 3) D4L; 4) D4R; 5) D4H; 6) I5N; 7) K6P; and 8) K8P.(ABSTRACT TRUNCATED AT 400 WORDS)

Alkaline Phosphatase↗
PubMed1991

Role of the tetrameric structure of Escherichia coli pyruvate oxidase in enzyme activation and lipid binding.

Pyruvate oxidase of Escherichia coli, an enzyme greatly activated by phospholipids, is a tetramer of a Mr 62,000 subunit. We have utilized the differing electrophoretic mobilities of several mutant oxidases on native polyacrylamide gels to study the role of the quaternary structure of the enzyme in the activation process. We found that when two poxB gene alleles coexisted in cells, heterotetrameric species were formed in addition to homotetramers. The concentration of each tetrameric species varied according to the concentration of the different subunits present, and the distribution seemed virtually identical to those expected from random mixing. We showed that the intrinsic activity of pyruvate oxidase was not affected by interactions among the four subunits. However, binding of the enzyme to lipids, a property required for function in vivo, required that a tetramer contain at least two subunits capable of lipid binding. Our data fit the model proposed previously (Grabau, C., Chang, Y.-Y., and Cronan, J. E., Jr. (1989) J. Biol. Chem. 264, 12510-12519) in which the carboxyl termini of two subunits interact to form a functional lipid-binding domain. We also have detected oxidase activity in a form of oxidase of unusually high electrophoretic mobility. This form seems to be either a monomeric or a dimeric form (more probably the former) of the oxidase subunit.

Binding Sites↗
PubMed1991

Cheiro-oral syndrome: identification of the lesion sites and a proposal for its clinical classification.

Five cases suffering from unilateral paresthesia over the corner of the mouth and the hand on the same side were examination for cheiro-oral syndrome. Of these, three cases were typical and the other were variant cases associate with transient hemi-signs. Lesion sites were identified by computed tomographic (CT) scan, magnetic resonance imaging (MRI) or both. Of the five patients, lesions were due to thalamic infarction in three cases, pontine hemorrhage in one case, and tumor compression on the right frontoparietal lobe in the last case. The pathophysiology of all cases were classified according to location of the lesion on the thalamus, the pons, and the parietal lobe, which are the usual anatomical sites responsible for this syndrome. Based on the three typical cases and thirteen cases cited from the English literature, a clinical classification has been established. The classification is based on age at the time of onset, gender, lesion site, etiology, risk factors, and certain clinical features. These sixteen cases fell into three distinct groups: a) those in which the thalamic lesions were related to infarction, b) those in which tumors, or in rare cases infarction, were found in the parietal lobe, and c) those in which hemorrhage occurred in the pons. Using this classification, the cheiro-oral syndrome can be more systematically defined.

Female↗
PubMed1989

Lipid binding by Escherichia coli pyruvate oxidase is disrupted by small alterations of the carboxyl-terminal region.

Escherichia coli pyruvate oxidase is a membrane-associated flavoprotein dehydrogenase which is greatly activated by lipids and detergents. The carboxyl-terminal region of the protein has been shown to play a critical role in the interaction with lipids. We report mutations generated by chemical and oligonucleotide-mediated site-directed mutagenesis of the poxB gene which result in enzymes defective in lipid activation. Nine mutants were isolated which encode enzymes with point mutations in the carboxyl-terminal segment of the protein. Two mutant lesions introduced termination codons giving enzymes lacking the last nine or three amino acids of the protein which were unable to interact with detergents in vitro and were unable to function in vivo. Of the missense mutants isolated, two were most informative. One was the substitution of Glu-564 with proline in the PoxB16 oxidase. This residue lies in the center of a putative lipid-binding amphipathic alpha-helix (Arg-558 to Thr-568) located close to the carboxyl terminus. Strains producing the PoxB16 oxidase were devoid of oxidase activity in vivo, the enzymes could not be activated by Triton X-100, and were activated poorly by phospholipids in vitro. These results indicated that the PoxB16 oxidase lacked normal lipid-binding ability. Another mutant oxidase (PoxB15) in which proline was substituted for Asp-560 at the beginning of the amphipathic alpha-helix had normal oxidase activity. These findings indicate that the amphipathic alpha-helix structure plays an essential role in the activation and lipid-binding properties of the enzyme. The second informative missense mutation was the substitution of the carboxyl-terminal arginine with glycine. This enzyme showed normal activation in vitro by phospholipids and some detergents, and somewhat reduced activity in vivo. This mutant enzyme appeared to dissociate from detergent vesicles more readily than does the normal enzyme. A model for the membrane interaction of the carboxyl terminus based on the properties of these mutant proteins is presented.

Alleles↗