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Biomedical subjects

M L Chou

Publications and source records attributed to M L Chou.

At least 19 recordsLinked to original sources
PubMed2001

EMF genes interact with late-flowering genes in regulating floral initiation genes during shoot development in Arabidopsis thaliana.

To investigate the mechanisms regulating the initiation of floral development in Arabidopsis, a construct containing beta-glucuronidase (GUS) gene driven by APETALA1 promoter (AP1::GUS) was introduced into emf fwa and emf ft double mutants. GUS activity was strongly detected on shoot meristem of emf1-1 single mutants harboring AP1::GUS construct just 5 d after germination. By contrast, GUS activity was undetectable on emf1-1 fwa-1, emf1-1 ft-1, emf2-1 fwa-1, emf2-3 fwa-1 and emf2-3 ft-1 double mutants harboring AP1::GUS construct 10 d after germination. GUS activity was only weakly detected on the apical meristem of 20-day-old emf1-1 fwa-1 and emf2-1 fwa-1 seedlings. During this time, only sessile leaves were produced. Further analysis indicated that AP1 was strongly expressed in 10-day-old emf1-1 and emf2-1 single mutants. Its expression was significantly reduced in all emf1-1 or emf2-1 late-flowering double mutants tested. Similar to AP1, the expression of LEAFY (LFY) was also high in emf1-1 and emf2-1 single mutants and reduced in emf1-1 or emf2-1 late-flowering double mutants. Our results indicate that the precocious expression of AP1 and LFY is dependent not only on the low EMF and FWA activities but also on the expression of most of the late-flowering genes such as FT, FCA, FE, CO and GI. These data also reveal that most late-flowering genes may function downstream of EMF or in pathways distinct from EMF to activate genes specified floral meristem identity during shoot maturation in Arabidopsis.

Alleles↗
PubMed2001

Heterocellular gap junctional communication between alveolar epithelial cells.

We analyzed the pattern of gap junction protein (connexin) expression in vivo by indirect immunofluorescence. In normal rat lung sections, connexin (Cx)32 was expressed by type II cells, whereas Cx43 was more ubiquitously expressed and Cx46 was expressed by occasional alveolar epithelial cells. In response to bleomycin-induced lung injury, Cx46 was upregulated by alveolar epithelial cells, whereas Cx32 and Cx43 expression were largely unchanged. Given that Cx46 may form gap junction channels with either Cx43 or Cx32, we examined the ability of primary alveolar epithelial cells cultured for 6 days, which express Cx43 and Cx46, to form heterocellular gap junctions with cells expressing other connexins. Day 6 alveolar epithelial cells formed functional gap junctions with other day 6 cells or with HeLa cells transfected with Cx43 (HeLa/Cx43), but they did not communicate with HeLa/Cx32 cells. Furthermore, day 6 alveolar epithelial cells formed functional gap junction channels with freshly isolated type II cells. Taken together, these data are consistent with the notion that type I and type II alveolar epithelial cells communicate through gap junctions compatible with Cx43.

Animals↗
PubMed2001

Recurrence of pneumococcal meningitis due to primary spontaneous cerebrospinal fluid fistulas.

The authors report a case of pneumococcal meningitis which recurred 3 times in a Taiwanese boy due to spontaneous cerebrospinal fluid (CSF) fistulas. The first time occurred at the age of 2 years, and the second episode presented as meningoencephalomyelitis at the age of 6 years 10 months. Studies including serum levels of immunoglobulin and complements, brain magnetic resonance imaging, and coronal cranial computed tomography (CT) were negative for a specific etiology. The third episode of meningitis developed 2 months after the second episode. Repeated immunological studies and high-resolution CT of paranasal sinuses and temporal bones were negative. Technetium-99m diethylenetriamine pentaacetic acid (Tc-99m-DTPA) radionuclide cisternography revealed abnormal retention of radioactivity over the right mastoid area. Neurosurgery was undertaken to seal the dural tear and pack the petrosal fissure. Two years after surgery, he has had no further CSF leak age or meningitis. Tracing back the history, there was no head injury, cranial surgery, brain tumor, or hydrocephalus, which might have created CSF fistulas. Primary spontaneous CSF fistulas constitute the most reasonable diagnosis. In cases of recurrent bacterial meningitis, underlying anatomic defects should be carefully evaluated if there is no immune defect.

Cerebrospinal Fluid Rhinorrhea↗
PubMed1999

FLD interacts with CO to affect both flowering time and floral initiation in Arabidopsis thaliana.

fld and co, both with significantly delayed flowering, are characterized as late-flowering mutations in Arabidopsis thaliana. Double mutants between fld-2 and co-3 were generated and the phenotypes characterized. Double mutants flower later than both single mutant parents, suggesting that there is an additive effect. In addition, the formation of flowers in double mutants was altered and showed a novel phenotype. Double mutant flowers contained a much longer stalk (pedicel). Sepals and petals were absent. Several leaf-like structures were produced in the position normally occupied by sepals and the organ numbers were reduced. The carpels were morphologically normal. The stamens produced were usually aborted in the early stage, thus, the flowers were sterile. The additive phenotype observed in double mutants provides evidence to support that these two genes, FLD and CO, are not only involved in rosette-to-inflorescence transition but also involved in the flower formation. This result also indicates that FLD and CO promote the reproductive program through two different pathways.

Arabidopsis↗
PubMed1999

Late-flowering genes interact with early-flowering genes to regulate flowering time in Arabidopsis thaliana.

To investigate the genetic mechanisms regulating the transition from the vegetative to reproductive growth in Arabidopsis, double mutants between three different early-flowering mutants, early flowering 1-1, 2-1, 3-1, (elf 1-1, 2-1, 3-1) and five different late-flowering mutants, gi-1, ft-1, fwa-1, ld-1, and fca-9, were constructed and phenotypes analyzed. Double mutants in all combinations displayed the late-flowering phenotypes which resembled their respective late-flowering parents in both flowering time and the number of vegetative leaves produced. The results indicate that five late-flowering mutants are epistatic to all three early-flowering mutants tested here. This epistatic relationship suggests that ELF1, ELF2, and ELF3 genes function upstream of these five late-flowering genes no matter if they are functioning in autonomous or photoperiod pathways. These three early-flowering genes may negatively modify the activity of most late-flowering genes to influence the time of the vegetative-to-reproductive transition in Arabidopsis.

Arabidopsis↗
PubMed1999

Phenotypic control of gap junctional communication by cultured alveolar epithelial cells.

We examined phenotype-specific changes in gap junction protein [connexin (Cx)] expression and function by cultured rat alveolar type II cells. Type II cells cultured on extracellular matrix in medium containing keratinocyte growth factor (KGF) and 2% fetal bovine serum (FBS; KGF/2) retained expression of surfactant protein C and the 180-kDa lamellar body membrane protein (lbm180). These markers were lost when cells were cultured in medium containing 10% FBS (MEM/10). With RT-PCR, cells cultured in MEM/10 showed transient increases in Cx43 and Cx46 mRNA expression, whereas Cx32 and Cx26 decreased and Cx30.3 and Cx37 were unchanged. Transient changes in Cx32, Cx43, and Cx46 protein expression were confirmed by immunoblot. In contrast, cells cultured in KGF/2 retained expression of Cx32 and showed increased expression of Cx30.3 and Cx46 mRNAs, compared with that in day 0 cells. With immunofluorescence microscopy, Cx32 and Cx43 were at the plasma membrane of cells grown in KGF/2, whereas Cx46 was exclusively intracellular. Type II cells cultured in MEM/10 showed approximately 3- to 4-fold more intercellular transfer of microinjected lucifer yellow through gap junctions than cells grown in 2% FBS. Thus type II cells dynamically alter gap junctional communication, and distinct alveolar epithelial cell phenotypes express different connexins.

Animals↗
PubMed1999

Non-typhoid Salmonella subdural empyema in children: report of two cases.

Subdural empyema caused by Salmonella in childhood is an uncommon condition. The predisposing factors for this condition are not clearly established, especially in young children. Here we present two cases of subdural empyema caused by non-typhoidal Salmonella. Both of the patients suffered prolonged fever without local signs of infection on admission. Subdural empyema was subsequently detected by brain echo and brain computerized tomography (CT) scan in both cases. Cerebrospinal fluid (CSF) study was not done in case one due to prominent mass effect on brain CT; in case two the CSF analysis showed pleocytosis, but CSF bacterial culture was negative. Neither enteritis nor obvious meningeal sign was noted. Both cases responded well to surgical drainage and systemic antibiotics treatment.

Child, Preschool↗
PubMed1998

Benign isolated abducens nerve palsy in Mycoplasma pneumoniae infection.

Benign acquired isolated abducens nerve palsy in children is a rare condition. The palsy may be due to a postinfectious process; Epstein-Barr virus and cytomegalovirus have been documented etiologies. This is a case report of a boy 26 months of age with benign acquired isolated bilateral abducens nerve palsy. It may be the first report of Mycoplasma pneumoniae as the cause of benign isolated abducens nerve palsy in children.

Abducens Nerve↗
PubMed1998

FLD interacts with genes that affect different developmental phase transitions to regulate Arabidopsis shoot development.

A new fld mutant allele, fld-2, which significantly delayed flowering, was isolated and characterized in Arabidopsis thaliana. Even under long-day conditions after more than 100 days in the greenhouse, the majority of fld-2 mutant plants had not bolted. In addition, mutant inflorescences produced more than 10 co-florescences that were subtended by a high number of rosette-like leaves before giving rise to flowers. The late-flowering phenotype of the fld-2 mutation could be partially overcome by both vernalization and GA treatment but it was not influenced by 5-azaC treatment. Phenotypic analyses of double mutants indicated that fld-2 is epistatic to early flowering mutants elf1, elf2 and elf3. In addition, fld-2 could enhance vegetative characteristics in embryonic flower 1 (emf1) mutants by causing many small sessile leaves in fld-2 emf1 double mutants. The relief of the terminal flower 1 (tfl1) mutant phenotype in fld-2 tfl1 double mutants, and the enhancement of leafy (lfy) and apetala1 (ap1) mutant phenotypes in fld-2 lfy and fld-2 ap1 double mutants, suggest that FLD is also likely to be involved in the floral transition. Our results strongly suggest that the FLD gene plays a key role in regulating the reproductive competence of the shoot and results in different developmental phase transitions in Arabidopsis.

Arabidopsis↗
PubMed1997

Ultrasonographic study of the sternocleidomastoid muscle in the management of congenital muscular torticollis.

BACKGROUND: Congenital muscular torticollis (CMT) in infancy is caused by the fibrotic change of the sternocleidomastoid muscle (SCMM). The etiology and management strategies remain controversial. METHODS: One hundred ninety-seven infants and children aged 1 month to 16 years who had CMT were examined by real-time ultrasonography of the SCMM between June 1995 and September 1996 in a prospective and longitudinal study. A total of 362 examinations were performed. There were 122 boys and 75 girls. RESULTS: The right side was involved in 117 patients (59.3%), the left side in 79 patients (40.1%), and both sides in one patient. The sonographic findings were homogeneous or heterogeneous (patchy) hyperechoic lesion within the SCMM, and all were diagnostic. The ultrasonographic appearance of the SCMM in this study has a close resemblance to the clinical course of CMT. The extent of fibrosis as represented by the cross section of lesion to muscle ratio (L/M ratio) decreased from 83.6% at 2 months to 59.9% at 9 months of age and further decreased to 40% beyond 1 year of age. This consistent decrease in fibrosis was caused by the increased normal muscle volume at the periphery and by the regenerated muscle fibers within the lesion. In this series of 197 patients, 32 (16.2%) eventually underwent surgery to release the SCMM because of persistent head tilt, chin deviation and limited range of neck motion beyond 1 year of age. The L/M ratio of the operative group was 62.7 +/- 16.0% compared with an L/M ratio of 54.5 +/- 14.2% (P = .035) for the nonoperative group at 1 year of age. The extent of fibrotic change in the cross section of the muscle was a significant factor in determining prognosis. In the longitudinal section, the fibrotic change was limited to only the lower third of the SCMM in 27 patients, and all of them recovered without operation. In 95 patients, the fibrotic lesion was limited to the middle and lower third or middle third only, and only six (6.3%) underwent operation. However, in 75 cases the entire length of muscle was involved, and 26 (34.7%) required surgical release of the contracted muscle. Whole-length muscle involvement was also important for predicting recovery without operative intervention. CONCLUSIONS: Ultrasonographic study of the SCMM is not only a valuable diagnostic tool but can also serve as a useful guideline for the treatment of infants who have congenital muscular torticollis.

Adolescent↗
PubMed1997

Role of cavum septum pellucidum in akinetic mutism of hydrocephalic children.

Two children 9 and 13 years of age with histories of aqueductal stenosis developed akinetic mutism after multiple shunt revisions. The girl had spontaneous relief of her akinetic mutism 1 month later, after parenteral antibiotics and multiple shunt revisions. The akinetic mutism of the boy was resistant to antiparkinsonian therapy before megadosage of bromocriptine (120 mg/day). Both children had a prominent cavum septum pellucidum (CSP), which has rarely been involved in the pathogenesis of akinetic mutism. Because of the rapid shrinkage of the girl's CSP after shunt revision, but not that of the boy even after stereotactic fenestration of the wall of his CSP, their eventual outcomes were different. Wide CSP (WCSP) may play an important role in the occurrence of akinetic mutism in hydrocephalic patients.

Adolescent↗
PubMed1996

Bacterial tracheitis: a case report.

An 18-month-old girl was brought to the emergency room of Chang Gung Children's Hospital with inspiratory stridor, suprasternal retractions and imminent respiratory failure. Despite orotracheal intubation, persistent poor air-entry was noted. Flexible bronchoscopy via the endotracheal tube showed a copious amount of mucopurulent secretions in the tracheobronchial tree without any foreign bodies. With vigorous suctioning and antibiotic treatment, she had a rapid recovery. Tracheal aspirates showed a growth of Haemophilus influenzae. Cefamandole was used with good response. In conclusion, although bacterial tracheitis is an uncommon obstructive upper airway disease in children, using a bronchoscope to diagnose and to guide specific therapy can decrease the morbidity and mortality.

Bronchoscopy↗
PubMed1994

Choreoathetosis as an initial sign of relapsing of herpes simplex encephalitis.

Twelve children with type 1 herpes simplex encephalitis (3 with relapse, 9 without) have been monitored during the past 7 years. Ten of the children received intravenous infusion of acyclovir (30 mg/kg/day) for 10 days, 1 child who experienced relapse received 15 mg/kg/day, and another relapsed child received no antiviral agents until relapse. Relapse occurred 20-36 days after initial onset. All relapsed patients underwent another 10 days of acyclovir treatment (30 mg/kg/day). Choreoathetosis appeared as the initial sign of relapse followed by rapidly progressive unresponsiveness in all 3 relapsed patients: in 1 nonrelapsed patient choreoathetosis occurred during the recovery period. In these 4 patients involuntary movement was remitted within 3 months to 2 years. One patient with choreoathetosis died of measles pneumonia 4 months after onset of herpes simplex encephalitis and the surviving 3 were severely retarded. Although neuroimaging sparing of basal ganglia does not indicate structural and functional abnormalities, the disturbance of the neural connection among the basal ganglia and the cerebral cortex, which manifested severe damage over frontal, temporal, and parietal mantles on CT, may be the source of movement disorders in these patients. We conclude that choreoathetosis may be the first sign of relapse of herpes simplex encephalitis in children and may be an indicator of poor prognosis. The neuropathogenesis of choreoathetosis requires further investigation.

Acyclovir↗
PubMed1992

Multiple cerebral aneurysms in a child with cardiac myxoma.

Neurologic involvement is not uncommon in cardiac myxoma, yet its association with multiple cerebral aneurysms is rare, especially in children. We describe a patient with left atrial and ventricular myxoma, who otherwise lacked cardiac symptomatology and did not exhibit auscultatory, roentgenologic, or electro-cardiographic evidence of heart disease. The clinical presentation was a sudden attack of a cerebrovascular occlusive disorder. Multiple fusiform aneurysms at the frontal and parietal branches of the left anterior and middle cerebral arteries were demonstrated on cerebral angiograms. The myxomas were surgically removed and the patient improved.

Child↗
PubMed1989

[Cytomegalovirus infection in neonate--report of two cases].

The cytomegalovirus (CMV) is an abiquitous agent that infects almost all human beings at some time during their lives. In developing area of the world, 90% or more of the population is infected during childhood. However, in developed countries the infection is acquired at a lower rate. In neonates, CMV infection can be divided into congenital and perinatal infection. Congenital CMV infection is the result of transplacental transmission, CMV can be transmitted to the fetus following reactivation as well as primary infection during pregnancy. The incidence of congenital infection is 0.2% to 2.2%. Symptomatic congenital CMV infection is more likely to be the result of primary as opposed to reactive CMV infection during pregnancy. The clinical manifestations of symptomatic CMV infection are hepatosplenomegaly, microcephaly, jaundice, petechiae, small for gestation age, periventricular calcification and chorioretinitis. Mortality may be as high as 30% among the most severely affected infants. In the survivors, about 90% will develop mild to severe handicaps. Perinatal CMV infection can be acquired from exposure to virus in the maternal genital tract at delivery, breast milk, or through blood transfusion. In premature infants who require prolonged and intensive medical care, blood transfusions are an important iatrogenic cause of CMV infection. Transfusion-acquired perinatal CMV infection can cause significant morbidity and mortality, particularly in premature infants with a birth weight of less than 1250 gm born to CMV-seronegative mothers. So CMV acquisition can be prevented either by providing these infants blood products from seronegative donors or by using frozen deglycerolized red blood cells. Two cases of neonatal CMV infection are reported, one with congenital infection, the other with perinatal infection.

Cytomegalovirus Infections↗
PubMed1984

Intracranial hemorrhage and vitamin K deficiency in early infancy.

We report late-onset (1/2 to 6 months of age) intracranial hemorrhage related to vitamin K deficiency in 32 breast-fed infants, 31 of whom received no prophylactic vitamin K at birth. Computerized tomography showed mild to severe intracranial hemorrhage. Most (90.6%) had subarachnoid hemorrhage, either alone or in combination with subdural hemorrhage (37.5%), parenchymal hemorrhage (31.3%), or intraventricular hemorrhage (12.5%). In three (9.4%) the infratentorial region was involved.

Breast Feeding↗