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Biomedical subjects

T Y Lin

Publications and source records attributed to T Y Lin.

At least 91 records · Page 5Linked to original sources
PubMed1999

Ultrasonographic diagnosis and color flow Doppler sonography of internal jugular venous ectasia in children.

We investigated the diagnostic utility of ultrasonography in the diagnosis of internal jugular venous ectasia. Eight children (six boys, two girls) were recruited into this prospective study. Sonography of internal jugular venous ectasia in these patients revealed fusiform dilation of the internal jugular vein, and the possibility of thrombus and external compression could be ruled out. Marked variation in size of ectatic jugular veins during respiration was demonstrated under real-time sonography. The mean anteroposterior diameter of these dilated internal jugular veins was 0.79+/-0.18 mm (mean+/-standard deviation), which increased to 1.58+/-0.27 mm with Valsalva maneuver. Our study showed that the anteroposterior diameters of the internal jugular veins in cases of ectasia were greater than those of contralateral jugular veins in same patients as well as those in normal children, and they showed greater increase after Valsalva maneuver. Under color Doppler flow studies, turbulent vascular flows were demonstrated in these patients with jugular venous ectasia. No progression of venous ectasia was found in any of our patients during a 6 month follow-up period. We conclude that internal jugular venous ectasia in children is a benign condition, which usually does not require surgical intervention. Ultrasonography is a good diagnostic modality for the diagnosis of internal jugular venous ectasia. Color Doppler ultrasonography demonstrate the turbulent flow in jugular venous ectasia.

Blood Flow Velocity↗
PubMed1999

Colour Doppler ultrasonography of retropharyngeal abscess.

OBJECTIVE: This study was conducted to determine the capability of colour Doppler ultrasonography (CDU) in evaluating retropharyngeal abscess in children. MATERIALS AND METHODS: From July 1996 to February 1998, five children with clinical suspicion of retropharyngeal abscess were evaluated by CDU. The distance from internal carotid artery (ICA) to cervical vertebra (CV) (DICA-CV) at the upper cervical level was measured by longitudinal ultrasonography. Fifty healthy children, aged from 1 to 15 years, were recruited in the study to measure DICA-CV as control. Colour Doppler ultrasonography was used to differentiate abscess from other pathology and to detect carotid sheath invasion. Computed tomography was performed to confirm the sonographic diagnosis. Measurements of the DICA-CV at regular intervals were performed to monitor the progression of retropharyngeal abscess. RESULTS: Retropharyngeal abscess was highly suspected in all cases under sonographic studies. A patient was found to have carotid sheath invasion. Computed tomography confirmed the diagnosis of retropharyngeal abscess in all cases. Retropharyngeal abscess can be evaluated by the measured DICA-CV. The DICA-CV decreased as the retropharyngeal abscess gradually resolved. CONCLUSION: Colour Doppler ultrasonography offers a sensitive method to evaluate retropharyngeal abscess in children. It can also be used to monitor the progression of retropharyngeal abscess and avoid unnecessary radiologic examinations.

Adolescent↗
PubMed1999

Prevention of hypotension after spinal anesthesia for cesarean section: dextran 40 versus lactated Ringer's solution.

BACKGROUND: This study was designed to compare the efficacy of 10% dextran 40 with lactated Ringer's (LR) solution in reducing the incidence and severity of hypotension after spinal anesthesia for Cesarean section. METHODS: Sixty ASA grade I patients scheduled for Cesarean section were randomized into two groups in a double-blind fashion to receive either 500 ml of dextran 40 or 1000 ml of LR solution prior to induction of spinal anesthesia. RESULTS: The incidence of hypotension was 16 in 30 (53.3%) in the LR solution group and 8 in 30 (26.7%) in the dextran group (P < 0.05). The required dose of ephedrine for treatment of hypotension was significantly greater in the LR solution group than in the dextran group (15.5 mg versus 3.2 mg, P < 0.05). Neonatal outcome, as determined by Apgar score, was good and similar in both groups. CONCLUSIONS: We concluded that 500 ml of dextran 40 is more effective than 1000 ml of lactated Ringer's solution in reducing the incidence of hypotension induced by spinal anesthesia.

Adult↗
PubMed1999

Clinical and computed tomographic features of tracheal bronchus in children.

We retrospectively reviewed the records of all children who received bronchoscopic studies in our hospital from July 1994 through June 1998, to identify cases of tracheal bronchus. During the 4-year period, 462 children underwent a total of 492 bronchoscopic studies. Eleven (2.4%) of these children (9 boys, 2 girls, aged 1 mo to 11 yrs) had tracheal bronchus. Most of these patients underwent bronchoscopy because of respiratory difficulties, but the symptoms were not attributable to tracheal bronchus in 10 of the 11 children. Six out of the 11 patients had coexisting tracheobronchial stenosis. Bronchoscopy indicated high bifurcation of the carina in one patient, and direct coronal computed tomography demonstrated concomitant tracheal stenosis and tracheal bronchus. Most patients with tracheal bronchus can be treated conservatively. Correction of the underlying abnormalities is of paramount importance for the relief of respiratory symptoms.

Bronchi↗
PubMed1998

Activating a zymogen without proteolytic processing: mutation of Lys15 and Asn194 activates trypsinogen.

The zymogen and mature enzyme forms of trypsin-like serine proteases exhibit a wide range of activities. The prototypical trypsinogen-trypsin system is an example of a minimally active zymogen and a maximally active mature protease. The present work identifies several features of trypsinogen which govern its activity. Our results indicate that rat trypsin is 10(8)-fold more active than rat trypsinogen. Rat trypsinogen appears to be less active than bovine trypsinogen. His40 is believed to be an important determinant of zymogen activity. We are unable to verify this role for His40 in trypsinogen since the mutation of His40 to Phe appears to change the trypsin-substrate interface. Deletion of the N-terminal Ile16 from trypsin is expected to produce a trypsinogen-like protein since the Ile16-Asp194 salt bridge cannot form. Such mutants have higher activity and BPTI affinity than trypsinogen, which indicates that the activation peptide stabilizes the inactive trypsinogen conformation. The mutation of Lys15 to Ala increases the BPTI affinity and activity of trypsinogen to an even greater extent; thus, removal of Lys15 can account for the effect of the loss of the activation peptide. These results suggest that Lys15 is an important determinant of zymogen activity. The mutation of Asp194 to Asn also increases the BPTI affinity and activity of trypsinogen. This result suggests that in addition to stabilizing the active conformation of trypsin via the Ile16-Asp194 salt bridge, Asp194 also maintains the inactive conformation of trypsinogen. A correlation exists between the values of kcat/Km and BPTI affinity of mutant trypsinogens and trypsins. However, the slope of this correlation is 0.64, which indicates that different "active" conformations are involved in BPTI binding and substrate hydrolysis. DeltaI16V17 trypsinogen is the lone outlier; its BPTI affinity is higher than would be expected based on the value of kcat/Km. We show that the rate of BPTI association is slower for DeltaI16V17 trypsinogen than for a mutant trypsinogen with a similar BPTI affinity. This observation suggests that BPTI binds to an "active" trypsinogen conformation that is not kinetically accessible to substrates.

Animals↗
PubMed1998

Characterization and functional analysis of the porcine lactoferrin gene promoter.

Lactoferrin, a ferric binding glycoprotein found in milk, can possibly prevent microbial infection of the mammary gland and gastrointestinal tract. To define the regulation of the porcine lactoferrin gene (pLTF), we cloned its 5'-flanking region from a porcine liver genomic library and analyzed the 5' upstream region of approx. 4kb, two exons, and an intron. The transcription start site was localized by primer extension to residue G, which is 41 nucleotides upstream from the ATG start codon. The pLTF 5'-flanking region possesses several putative cis-acting regulatory elements found in both housekeeping and inducible genes; to define their function, they were inserted into a chloramphenicol acetyltransferase reporter construct. The region up to -156 sufficed for basic promoter activity, whereas the region up to -780 was required for maximal promoter activity in porcine testis cells (STcells), kidney cells (PK15 cells) and human mammary epithelial cells (HBL-100 cells). Detailed analysis of this proximal region by DNase I footprinting and electrophoretic mobility shift assays reveals that the ubiquitous factors SP1, AP2 and the mammary gland-specific factor (MGF) might play significant roles in regulating the transcription of the pLTF gene.

Animals↗
PubMed1998

Downregulation and subcellular redistribution of the gamma-aminobutyric acidA receptor induced by tunicamycin in cultured brain neurons.

The significance of N-linked glycosylation and oligosaccharide processing was examined for the expression of gamma-aminobutyric acidA receptor (GABA(A)R) in cultured neurons derived from chick embryo brains. Incubation of cultures with 5 microg/ml of tunicamycin for 24 h blocked the binding of 3H-flunitrazepam and 3H-muscimol, probes for the benzodiazepine and GABA sites on the receptor, by about 20% and 28%, respectively. The loss of ligand binding was due to a reduction in the number of binding sites with no significant changes in receptor affinity. Light microscopic immunocytochemistry also revealed that the treatment reduced approximately 13% of the intensity of GABA(A)R immunoreactivity in the neuronal somata. Furthermore, the fraction of intracellular receptors was decreased to 24% from 34% of control in the presence of the agent, as revealed by trypsinization of cells in situ followed by 3H-flunitrazepam binding. The molecular weight of the receptor subunit protein was lowered around 0.5 kDa after tunicamycin treatment, in accordance with that following N-glycosidase F digestion, indicating the blockade of N-linked glycosylation of GABA(A)R by tunicamycin. Moreover, intense inhibitions of 91% and 44%, respectively, were detected to the general galactosylation and mannosylation in the tunicamycin-treated cells, whereas the protein synthesis was hindered by 13%, through assaying the incorporation of 3H-sugars and 3H-leucine. Nevertheless, treatment with castanospermine or swainsonine (10 microg/ml, 24 h), inhibitors to maturation of oligosaccharides, failed to produce significant changes in the ligand binding. In addition, in situ hybridization analysis showed that these three inhibitors did not perturb the mRNA of GABA(A)Ralpha1-subunit. The data suggest that tunicamycin causes the downregulation and subcellular redistribution of GABA(A)R by producing irregularly glycosylated receptors and modifying their localization. Both galactosylation and mannosylation during the process of N-linked glycosylation may be important for the functional expression and intracellular transport of GABA(A)R.

Animals↗
PubMed1998

Congenital tracheobronchial stenosis in monozygotic twins.

UNLABELLED: A pair of monozygotic twins suffering from noisy respirations and recurrent wheezes since early infancy were referred for evaluation. Using direct coronal CT and 3-dimensional reconstruction of the airway, congenital tracheobronchial stenosis was found in both twin babies, later confirmed by fibre optic bronchoscopy. The cause of congenital tracheobronchial stenosis remains obscure, but even in monozygotic twins an unidentified environmental factor cannot be excluded and may be responsible for discordant bronchopulmonary abnormalities. CONCLUSION: This case report shows that tracheobronchial stenosis may present in monozygotic twins. The pattern of malformation in twins differs from cases described previously.

Bronchial Diseases↗
PubMed1998

Yeast carriage on hands of hospital personnel working in intensive care units.

The frequency and distribution of yeast carriage on the hands of hospital personnel working in intensive care unit (ICUs), was investigated. Hand carriage of yeast and Candida species was 46 and 29%, respectively. Rhodotorula sp. and Candida parapsilosis were most frequently recovered. There was no significant difference in frequency or distribution of yeasts and Candida sp. recovered among the three ICUs. Seventeen C. parapsilosis isolates and three Candida albicans isolates were genotyped by electrophoretic karyotyping using contour-clamped homogenous electric-field gel electrophoresis. Eleven separate types of C. parapsilosis and two types of C. albicans were identified. There was no common genotype among these isolates, even within the same unit. We conclude that yeast carriage on the hands of personnel working in ICU is common, but these yeasts are usually not acquired from a common source in the ICU.

Candida↗
PubMed1998

Hair growth cycle affects hair follicle destruction by ruby laser pulses.

It has been shown that normal mode ruby laser pulses (694 nm) are effective in selectively destroying brown or black pigmented hair follicles in adult Caucasians. This study investigated how the various stages of the hair follicle growth cycle influence follicle destruction by ruby laser treatment, using a model of predictable synchronous hair growth cycles in the infantile and adolescent mice. A range of ruby laser pulse fluences was delivered during different stages of the hair growth cycle, followed by histologic and gross observations of the injury and regrowth of hair. Actively growing and pigmented anagen stage hair follicles were sensitive to hair removal by normal mode ruby laser exposure, whereas catagen and telogen stage hair follicles were resistant to laser irradiation. Selective thermal injury to follicles was observed histologically, and hair regrowth was fluence dependent. In animals exposed during anagen, intermediate fluences induced nonscarring alopecia, whereas high fluences induced scarring alopecia. The findings of this study suggest treatment strategies for optimal laser hair removal.

Alopecia↗
PubMed1998

Antimicrobial susceptibilities of Campylobacter jejuni and coli by using E-test in Taiwan.

To report the in vitro antibiotic susceptibility of Campylobacter species, we determined the MICs of 6 antibiotics by E-test for 93 human clinical strains and 35 chicken strains. The 6 antimicrobial agents tested were gentamicin, erythromycin, clindamycin, tetracycline, ciprofloxacin, and nalidixic acid. Isolates from humans were significantly more susceptible than chicken strains to erythromycin, clindamycin and ciprofloxacin. Nearly all of the human and chicken strains were susceptible to gentamicin. Among human isolates of C. jejuni, cross-resistance between nalidixic acid and ciprofloxacin was found in 66% of the strains, but none of the nalidixic acid-susceptible strains was resistant to ciprofloxacin. The higher prevalence of ciprofloxacin resistance in this area may be attributable to the large amount use of quinolones in poultry. Because of the high resistance rates of chicken isolates to the commonly used antimicrobial agents, it is necessary to create innovative methods to limit the inappropriate use of antibiotics in poultry in order to prevent the spread of the drug-resistant strains to humans.

Animals↗
PubMed1998

Outbreak of Candida albicans fungaemia in a neonatal intensive care unit.

During a 4-month period, 9 premature infants hospitalized in a neonatal intensive care unit (NICU) developed Candida albicans fungaemia. All 9 infants received antifungal agents. Fluconazole was administered in 7 patients and successfully eradicated this organism in 6 with no adverse effects. For epidemiological investigation, 64 environmental specimens and hand-washings of all 54 staff members involved in the NICU were examined for the presence of this organism. No C. albicans could be identified from environmental sources, while the hand-washing of 1 nurse was C. albicans-positive. Two genotyping methods, including electrophoretic karyotyping using contour-clamped homogeneous electric field gel electrophoresis and polymerase chain reaction-based direct sequencing of rRNA gene, were used in the analysis of the isolates recovered from blood cultures of the infants, the hand-washing of the nurse and 7 control isolates. Both methods yielded comparable results and revealed that all 13 isolates from infected infants as well as the isolate from hand washing of the nurse were of the same genotype while the control isolates were distinct. These results suggest that the outbreak of C. albicans fungaemia was caused by a particular strain and possibly via cross-infection. In addition, we showed that fluconazole seemed to be safe and effective in treating C. albicans fungaemia in neonates, although the data were limited.

Antifungal Agents↗
PubMed1998

Association of fungal colonization and invasive disease in very low birth weight infants.

BACKGROUND: Fungi are common pathogens of nosocomial infections in the very low birth weight (VLBW) infants. The purpose of this study was to investigate the fungal colonization rate in VLBW infants and the association between fungal colonization and systemic fungal diseases. MATERIALS: Between January 1, 1996, and December 31, 1996, 116 infants with birth weight < 1500 g admitted to the neonatal intensive care unit of Chang Gung Children's Hospital in the first day of life were included in this prospective study. METHODS: Cultures from oropharynx, rectum, skin (groin and axilla), bag urine and endotracheal aspirates were obtained in the first 24 h after birth and weekly thereafter throughout their neonatal intensive care unit stay. Medical records were reviewed weekly. RESULTS: Fungal colonization was detected in 25 infants, among whom 17 infants developed colonization by 2 weeks of life. Candida albicans (61%) and Candida parapsilosis (29%) were the 2 most common organisms. The rectum (76%) was the most frequent site of colonization. Factors significantly associated with colonization were prolonged administration of antibiotic therapy, parenteral nutrition and intralipid emulsion. Three of 116 infants developed fungemia. The association between colonization and subsequent fungemia was demonstrated in 1 infant, representing 4% of colonized infants. CONCLUSION: Fungal colonization was detected in one-fifth of VLBW infants and represents a risk factor for fungemia. Because disease occurred in the absence of apparent colonization, factors other than colonization may contribute to invasive candidiasis.

Candida↗
PubMed1998

Hypothermia predisposing to Pseudomonas putida sepsis in a child with panhypopituitarism.

A 14-year-old boy presented with a 1-week history of hypothermia and obtundation. His medical history included surgical resection of craniopharyngioma with postoperative visual impairment and panhypopituitarism. The patient's rectal temperature remained persistently lower than 35 degrees C during the first 3 days of hospitalization. His blood pressure was 90/56 mmHg on admission. The peripheral blood leukocyte count was 2.7 x 10(10)/L with 18% neutrophils, 19% band forms, 44% metamyelocytes, 3% myelocytes, and 16% lymphocytes. The C-reactive protein concentration was 133.9 mg/L. Two separate blood cultures both yielded Pseudomonas putida. The patient was treated with amikacin and ceftazidime along with aggressive fluid therapy. Replacement therapy directed at his hormonal deficiencies was initiated as soon as his hemodynamic status was stabilized. The patient responded well to therapy with a gradual rise in body temperature and improvement in general activity. A growth experiment carried out on the P. putida isolate showed that the bacteria grew more rapidly at 30 degrees C than at 37 degrees C. The clinical course of the patient, as well as the results of the laboratory study, suggest that hypothermia may predispose human infection with P. putida.

Adolescent↗
PubMed1998

Hemoptysis in children.

BACKGROUND: Hemoptysis is rare in children, yet is one of the most frightening manifestations of cardiopulmonary disease. A wide spectrum of diseases has been reported to cause hemoptysis in children, but the search for a specific cause can be tedious and unrewarding. Early diagnosis and interventions of hemoptysis are extremely important for the successful management of this potentially lethal process in children. METHODS: From July 1994 to June 1996, 15 pediatric patients ranging from 1 month to 15 years of age were admitted to the Pulmonology division for the investigation of hemoptysis. We retrospectively reviewed the clinical records and diagnostic evaluations of these patients. RESULTS: Six (40%) of the patients investigated were infectious in origin, only one patient had tuberculous infection. Three patients had a traumatic cause and 2 patients had foreign bodies in the airway. Two cases had no obvious contributing cause of hemoptysis despite extensive investigations. One patient had hematemesis because bleeding from esophageal ulcerations was misinterpreted as hemoptysis. One patient had varicosed tracheal and bronchial collaterals causing massive hemoptysis due to portal vein obstruction and hypertension. CONCLUSION: Pulmonary infection was the leading cause of hemoptysis in the 15 children we studied, but Mycobacterium tuberculosis is an uncommon causative agent. Bronchoscopy is an extremely useful tool for the diagnosis and localization of hemoptysis. Hematemesis may be misinterpreted as hemoptysis, particularly when an accurate history is not possible in children, therefore, bleeding from the upper aerodigestive tract should be studied meticulously and excluded adequately using endoscopy.

Adolescent↗