Biomedical subjects
Publications and source records attributed to T Y Lin.
Enteritis developed in a 42-day-old female infant, and during hospitalization ileal perforation occurred unexpectedly. Serologic data, urinary viral culture, and pathologic studies of the resected ileal segment all suggested cytomegalovirus infection. Gastrointestinal involvement in congenital or perinatal infection with this virus may be relatively more common than previously recognized.
Anterior openbite (AOB) is an intricate occlusal problem. Treatment of AOB is one of the most challenging tasks in orthodontics. An ethnic-specific norm for craniofacial skeletal patterns would be valuable in diagnosing and treating patients with AOB. To establish this norm for the people of Taiwan, a cephalometric study was conducted using the quadrilateral analysis developed by DiPaolo. The sample consisted of 15 males and 25 females in their 20s and 30s. The patients were randomly selected and were diagnosed with AOB. Various craniofacial skeletal patterns were measured, and these measurements were compared with values taken from a group of normal Taiwanese as well as with published values from a hyperdivergent group of westerners. The results support the following generalizations: (1) The growth pattern of subjects in the AOB group is hyperdivergent. (2) Both the maxillary and mandibular corpora of subjects with AOB are shorter than those of normal subjects. (3) The sagittal angle, average lower facial height, and the maxillary and mandibular sagittal ratio of subjects with AOB are larger than those of normal subjects. Abnormalities in the maxillomandibular complex causing changes in the vertical dimension of facial patterns are involved in AOB.
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Six children including two neonates with acute suppurative parotitis are described. They presented typical symptoms and signs of fever (4/6) and swelling (6/6), tenderness (6/6), erythema (4/6) and local warmness (4/6) of the parotid gland affected. Leucocytosis and an elevated erythrocyte sedimentation rate and serum amylase level may be seen. The presence of purulent discharge from the Stensen duct when the parotid gland is externally compressed is pathognomonic of the disease, and the microbiological diagnosis can be made by culture of the pus. Microbiologically, this series highlights the polymicrobic nature and importance of Streptococcus viridans in paediatric suppurative parotitis, indicating, therefore, that the causative bacteria entered the gland from the oral cavity. Our data also suggest that initial antibiotic therapy for such patients should provide adequate coverage for streptococci and staphylococci as well as for anaerobic bacteria.
Wild-type function of four Drosophila genes, spermatocyte arrest, cannonball, always early and meiosis I arrest, is required both for cell-cycle progression through the G2/M transition of meiosis I in males and for onset of spermatid differentiation. In males mutant for any one of these meiotic arrest genes, mature primary spermatocytes with partially condensed chromosomes accumulate and postmeiotic cells are lacking. The arrest in cell-cycle progression occurs prior to degradation of cyclin A protein. The block in spermatogenesis in these mutants is not simply a secondary consequence of meiotic cell-cycle arrest, as spermatid differentiation proceeds in males mutant for the cell cycle activating phosphatase twine. Instead, the arrest of both meiosis and spermiogenesis suggests a control point that may serve to coordinate the male meiotic cell cycle with the spermatid differentiation program. The phenotype of the Drosophila meiotic arrest mutants is strikingly similar to the histopathological features of meiosis I maturation arrest infertility in human males, suggesting that the control point may be conserved from flies to man.
We report a typical case of congenital varicella syndrome following a maternal varicella infection during the 10th week of pregnancy. The presenting symptoms in the small gestational age baby were: cicatricial skin lesion, Horner's syndrome,dysphagia with resulting aspiration pneumonia and delayed developmental milestones. Serologic studies revealed persistence of varicella zoster virus IgG for at least 10 months. Although congenital varicella syndrome is rare, it should be kept in mind when counseling families where maternal varicella infection has occurred during the first 20 weeks of gestation. A maternal history of varicella infection, typical manifestations and serologic proof are crucial in the diagnosis of congenital varicella syndrome.
We conducted a 3-year Taiwan-wide hospital-based survey of invasive Haemophilus influenzae infections in children less than 15 years of age. From January 1992 to December 1994, 105 cases (57 boys, 48 girls) were reported. Seventy-three patients (69.5%) had meningitis and 32 patients had other diseases (12 pneumonia, 10 sepsis, 7 cellulitis, 3 arthritis). Fourteen patients (13%) died, all of whom had meningitis or sepsis. Among the 63 patients who survived meningitis, 17 (27%) had neurologic sequelae and eight (47%) had hearing impairment. The number of cases of H. influenzae meningitis (30%) and other H. influenzae diseases (29%) peaked in children between 6 and 12 months of age. Patients with invasive infections (82%) and meningitis (73%) were younger than 24 months of age. Only 12 patients (11%) were older than 5 years of age and four had underlying diseases. The annual incidence of invasive H. influenzae infections in children less than 5 years old was 1.9 per 100,000 per year. During the same period a survey of purulent meningitis in children younger than 15 years of age was also conducted in 20 hospitals. A total of 198 patients, in whom the causative organisms were identified, were included; 94 patients were 2 months of age or under and the most frequent pathogen was group B streptococci (35 cases, 37%). Among the 104 patients who were older than 2 months of age, H. influenzae was the leading cause (38 cases, 37%). In conclusion, invasive H. influenzae type b (Hib) diseases exist in Taiwan but have an incidence lower than in Western countries. Hib meningitis is still the most common cause of purulent meningitis in children in Taiwan and is an important cause of mortality and morbidity. Continuous active surveillance of invasive H. influenzae infections is suggested to determine the best time to introduce an Hib conjugate vaccine in Taiwan.
Drug stability studies are expensive and time consuming. Multiple batches are studied to ensure that a product will consistently remain within specifications for its entire expiration dating period. Some of these studies involve the same drug products in similar packages or in multiple strengths. Application of sound statistical design principles can reduce the amount of testing required. We extend the principles stated in the Food & Drug Administration's 1987 publication Guideline for Submitting Documentation for the Stability of Human Drugs and Biologics to setting expiration dating periods for more complex situations.
Polyunsaturated fatty acids influence several steps involved in metastasis formation in animal tumor models. During the process of metastasis from the primary site, tumor cells adhere to the endothelium and underlying basement membrane before extravasation and secondary growth. The purpose of this study was to determine the effect of unsaturated fatty acids on adhesion of human breast cancer cell lines to components of the basement membrane. Cells were cultured in low-serum medium for five days with or without added unsaturated fatty acids. Adhesion assays were conducted by incubating cells with basement membrane substrates coated on 96-well plates, washing to remove nonadherent cells, and staining adherent cells with crystal violet. Linoleic acid (LA) and eicosapentaenoic acid increased adhesion of the metastatic cell line MDA-MB-231 to Matrigel and type IV collagen, while eicosapentaenoic acid decreased adhesion of the less metastatic cell line SK-BR-3 to these two basement membrane substrates. Oleic acid increased adhesion of MDA-MB-231 cells to Matrigel and fibronectin. Nordihydroguaiaretic acid and high concentrations of indomethacin, each of which inhibits the lipoxygenase pathway of arachidonate metabolism, were effective in reversing the stimulatory effect of LA on MDA-MB-231 cell adhesion. A protein kinase C inhibitor likewise suppressed the increase in adhesion observed when MDA-MB-231 cells were incubated in media with added LA. Unsaturated fatty acids modified the adhesive properties of human breast cancer cell lines in vitro, and LA appeared to increase human breast cancer cell adhesion to extracellular matrix components by activating lipoxygenase and/or protein kinase C pathways.
The effect of local massage on adverse reactions and immunogenicity of diphtheria-tetanus-pertussis vaccine was investigated. After diphtheria-tetanus-pertussis vaccination 327 infants were either massaged or not, and adverse reactions were evaluated. Local pain and fever were more frequent in the massage group. The extra febrile episodes from massage were mild (38-39 degrees C). For evaluation of the antibody responses, 124 infants were recruited into massage or nonmassage cohorts and antibody production was measured at 2, 6, 7, 18 and 19 months of age, respectively. Subjects in the massage group developed significantly higher antibodies against filamentous hemagglutinin at 6 and 7 months of age, pertussis toxin at 6, 7, 18 and 19 months of age, pertussis agglutinogen at 18 and 19 months of age and those in the nonmassage group. Local massage after diphtheria-tetanus-pertussis vaccination was associated with better immunogenicity and more adverse reactions, including low grade fever and local pain, which were mild and not particularly disturbing.
A previously healthy 30-day-old male infant became ill with fever, poor activity, and refusal to feed for 2 days. A cerebrospinal fluid examination revealed 7.15 x 10(8) leukocytes/l with 72% neutrophils, protein 4.6g/l, and glucose 7 mg/dl. Neisseria meningitidis was isolated from the blood and cerebrospinal fluid. On the fourth day of hospitalization, the baby was found to have left oculomotor and facial palsies, which resolved gradually. He was treated with intravenous penicillin for 2 weeks. A repeat CSF examination revealed a high persisting protein level of 2.9 g/l and a computerized tomographic brain scan revealed a cerebral infarction in the bilateral frontal lobes. The treatment was extended to 4 weeks. No relapse of the infection was noted. This is the first case report of an infant with meningococcal meningitis complicated by cranial nerve palsies and cerebral infarction. This and previous reports, show that meningococcal meningitis at an extremely young age is associated with a greater risk of developing neurological complications.
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We experienced six cases of congenital tracheal stenosis during a 3 years' period from October 1991 to September 1994 in Chang Gung Children's Hospital, Taiwan. The presenting symptoms of congenital tracheal stenosis varied from acute obstructive upper respiratory episodes in young childhood, stridor and wheezing since birth, recurrent bronchiolitis, difficult to intubate with endotracheal tube. Although bronchoscopy was diagnostic, but further imaging studies without anesthesia were equivocal. In spite of pericardial patch-tracheoplasties, the two cases undergoing surgery expired. During follow-ups, the remaining four patients suffered from persisting noisy respiration by conservative management.
The morphologic study of adults with true Class III malocclusion has seldom been reported. Tracings of lateral cephalograms of 51 Taiwanese adults with true Class III malocclusion were subjected to quadrilateral analysis. Means and standard deviations, t test, correlation analysis, and regressive analysis were used to compare the differences between this group and a reference population of adults with normal occlusion. The results indicated that the maxillary base is shorter and in a more retrusive position in adults with Class III malocclusion. Furthermore, the mandible is in a more protrusive position. The pattern of growth in the Class III malocclusion was found to be horizontal, that is hypodivergent. In diagnosis of the abnormality, the rule of the quadrilateral can provide assistance. That is, the maxillary base length, mandibular base length, anterior lower facial height, and posterior lower facial height can be used to evaluate the abnormality. In postural relationships the sagittal angle, vertical sagittal ratio, and horizontal sagittal ratio can be used as a reference.
Surface tension measurements were carried out at 20 degrees C by a capillary drop-weight method on aqueous solutions of sodium glutamate (NaGlu), lysine hydrochloride (LysHCl), potassium aspartate (KAsp), arginine hydrochloride (ArgHCl), lysylglutamate (LysGlu), argininylglutamate (ArgGlu), guanidinium sulfate, trehalose, trimethylamine N-oxide (TMAO), dimethyl sulfoxide, 2-methyl-2,4-pentanediol (hexylene glycol), and poly(ethylene glycol)s of molecular weights 200, 400, 600, and 1000. All of the salts and the sugar increased the surface tension of water, while the last four compounds decreased it, with 2-methyl-2,4-pentanediol lowering it most effectively and TMAO being the least effective. The preferential hydration of bovine serum albumin (BSA) and lysozyme was measured in KAsp, ArgHCl, LysGlu, and ArgGlu. The high values of preferential hydration found in all cases, except for BSA in ArgHCl, suggest that they should stabilize protein structure, as had been found for lysine hydrochloride and monosodium glutamate [Arakawa, T., & Timasheff, S. N. (1984) J. Biol. Chem. 259, 4979-4986]. A correlation was found for both BSA and lysozyme in KAsp, NaGlu, LysHCl, ArgGlu, and LysGlu between the surface tension effect and the observed preferential interactions, indicating that the change in the surface free energy of the protein-containing cavity due to the surface tension increase for water by these amino acid salts contributes dominantly to the observed increase in the chemical potential of the protein by their addition. The lack of a correlation observed for BSA, but not lysozyme, in ArgHCl at low concentrations where preferential binding is close to zero suggests, however, that the surface tension effect is not the sole factor involved in the protein-solvent interactions in these amino acid salts. Binding of ArgHCl to BSA, probably through hydrogen bonds between the Arg guanidinium group and peptide bonds, was proposed to occur, the affinity of Arg+ being reduced by electrostatic repulsion when proteins carry a net positive charge, such as is the case with lysozyme. Since the four organic solvent additives also lead to protein preferential hydration, no correlation exists between their preferential interactions and the surface free energy perturbation. Therefore, in their case, the preferential hydration must be ascribed to other factors that overcome the preferential binding expected from the Gibbs adsorption isotherm. The surface tension results, however, are consistent with the binding of the organic solvents to proteins through hydrophobic interactions, explaining, at least in part, the observed concentration dependence of the interactions.
Many organisms accumulate low molecular weight substances known as osmolytes when they experience environmental water stress. The main classes of osmolytes are sugars, polyhydric alcohols, amino acids and their derivatives, and methylamines, and all are known to be protein stabilizers. However, marine cartilaginous fishes and the coelacanth use, as osmolytes, a combination of urea and methylamines, i.e., a denaturant and a stabilizer, in a 2:1 molar ratio. Preferential binding and thermal denaturation measurements in the presence of each cosolvent separately and in their mixtures have been carried out using ribonuclease T1 (RNase T1) as the protein. At a 2:1 molar ratio of urea and trimethylamine N-oxide (TMAO), the effects of the two cosolvents on the transition temperature (Tm) were found to be essentially the algebraic sum of their effects when used individually. Preferential interaction measurements of urea, TMAO and urea in its 2:1 molar ratio mixture with TMAO, have shown that the presence of TMAO has no effect on the interaction of urea with the protein in either the native or the unfolded (reduced carboxymethylated RNase T1) state. The preferential interaction of TMAO in the presence of urea could not be measured for technical reasons. Calculations of transfer free energy in the two end states of the denaturation reaction have shown that 2 M urea destabilizes RNase T1 by 3.8 +/- 0.3 kcal/mol whether 1 M TMAO is present or not. The contribution of 1 M TMAO to stabilization is calculated to be 3.1 kcal/mol in the presence of 2 M urea and is measured to be 2.7 kcal/mol in its absence.
In a previous paper we reported the isolation of streptomycin-resistant mutants from Nicotiana plumbaginifolia and presented evidence for chloroplast control of the resistance trait. To understand the molecular basis of the resistance in these mutants, we sequenced three regions in the chloroplast 16s rRNA gene, which correspond to the 5' terminus, the 530 loop, and the 900 stem/loop of Escherichia coli 16s rRNA, and compared them with the sequences of the wild-type. Our results show that: (1) nine mutants have a C to T change at position 912, (2) one mutant (SR1021) has a G to A change at position 885, (3) one mutant has a C to T change at position 526, based on E. coli numbering; and (4) three mutants do not have any change in the regions analyzed. The point mutation detected in SR1021 has not been reported previously. In E. coli 16s rRNA, position 885 is protected from chemical probing by ribosomal protein S12 and is closely juxtaposed with the streptomycin-binding region (positions 912-915) in the predicted secondary structure. It is likely that the G to A transition at this position is a novel mutation for streptomycin resistance.