Biomedical subjects

H Lin

Publications and source records attributed to H Lin.

At least 55 records · Page 3Linked to original sources

PubMed2000

Physiological role of gap-junctional hemichannels. Extracellular calcium-dependent isosmotic volume regulation.

Hemichannels in the overlapping regions of apposing cells plasma membranes join to form gap junctions and provide an intercellular communication pathway. Hemichannels are also present in the nonjunctional regions of individual cells and their activity is gated by several agents, including calcium. However, their physiological roles are unknown. Using techniques of atomic force microscopy (AFM), fluorescent dye uptake assay, and laser confocal immunofluorescence imaging, we have examined the extracellular calcium-dependent modulation of cell volume. In response to a change in the extracellular physiological calcium concentration (1.8 to </=1.6 mM) in an otherwise isosmotic condition, real-time AFM imaging revealed a significant and reversible increase in the volume of cells expressing gap-junctional proteins (connexins). Volume change did not occur in cells that were not expressing connexins. However, after the transient or stable transfection of connexin43, volume change did occur. The volume increase was accompanied by cytochalasin D-sensitive higher cell stiffness, which helped maintain cell integrity. These cellular physical changes were prevented by gap-junctional blockers, oleamide and beta-glycyrrhetinic acid, or were reversed by returning extracellular calcium to the normal level. We conclude that nongap-junctional hemichannels regulate cell volume in response to the change in extracellular physiological calcium in an otherwise isosmotic situation.

Animals↗

PubMed2000

Translational repression: a duet of Nanos and Pumilio.

Recent studies have shed new light on translational repression by Nanos and Pumilio proteins. The ancestral function of this repression mechanism appears to be in early germline development; later, species-specific applications in embryonic patterning and spermatogenesis-oogenesis switching evolved.

Animals↗

PubMed2000

Interleukin-12 promotes neurite outgrowth in mouse sympathetic superior cervical ganglion neurons.

To determine the role of cytokines in the nervous system, we examined the effect of interleukin-12(IL-12) on the nerve regeneration of mouse superior cervical ganglion cells (SCG). IL-12 enhanced the neurite outgrowth in a concentration-dependent manner. Immunocytochemical studies demonstrated the expression of IL-12 receptors in neuronal bodies and neurites. The mRNA expression of IL-12 receptors in SCG cells was confirmed by reverse transcription-polymerase chain reaction. Our data demonstrated the presence of IL-12 receptors in sympathetic neurons and suggest that IL-12 plays an important role in neuronal regeneration.

Animals↗

PubMed2000

Anterolateral thigh vastus lateralis myocutaneous flap for vulvar reconstruction after radical vulvectomy: a preliminary experience.

BACKGROUND: There are many myocutaneous flap methods which have been reported for the immediate reconstruction of large vulvar defects created by deforming radical cancer surgery in the female perineum except for the anterolateral thigh vastus lateralis myocutaneous flap. The present report describes our preliminary experience with the use of this flap in a patient who underwent radical vulvectomy for locally advanced squamous cell carcinoma of the vulva. CASE: A 75-year-old woman underwent radical vulvectomy with bilateral inguinal lymphadenectomy due to right vulvar squamous cell carcinoma. The large vulvar defect was immediately reconstructed by using anterolateral thigh vastus lateralis myocutaneous flap. The postoperative course was uneventful. In addition to the expected primary healing, the neovulva had a relatively normal appearance with satisfactory sensation and function and the donor defect was found to be minimal both functionally and aesthetically. CONCLUSION: This technique can be used as an alternative method for vulvar reconstruction after radical vulvectomy. Further studies are warranted to prove the efficacy of this myocutaneous flap in reconstructing large vulvar defects.

Aged↗

PubMed2000

High external parametrial dose can increase the probability of radiation proctitis in patients with uterine cervix cancer.

OBJECTIVE: The aim of this study was to evaluate the relationship between external parametrial dose and radiation proctitis after external irradiation and high-dose-rate intracavitary (HDR-IC) brachytherapy among patients with cervical cancer. METHODS: From May 1993 through December 1996, 191 patients with stage IB-IVA cervical cancer were managed by curative-intent radiotherapy. External irradiation to the whole pelvis (44-45 Gy/ 22-25 fractions) was delivered to all patients initially. One hundred twenty-seven patients received additional bilateral parametrial and sidewall boost (5.4-14.4 Gy/ 3-8 fractions) with 4-cm midline shielding. HDR-IC brachytherapy, 19.2-24 Gy/ 5 fractions to Point A, was given after external irradiation. Patients receiving an external dose of 44-45, 50-54, and >54 Gy were categorized as no parametrial boost (NPMB), low parametrial boost (LPMB), and high parametrial boost (HPMB) group, respectively. The actuarial proctitis rate was compared among the three groups. RESULTS: Three-year overall and Grade 2-4 proctitis rates were 30 and 15%, respectively. Overall proctitis rates were 12, 34, and 51% in the NPMB, LPMB, and HPMB groups (P < 0.0001), respectively. Grade 2-4 proctitis rates were 5, 17, and 27% in the NPMB, LPMB, and HPMB groups (P = 0.0022), respectively. In multivariate analysis of overall and Grade 2-4 radiation proctitis, external parametrial dose was the only independent prognostic factor (P = 0.0002 and 0.0030, respectively). CONCLUSION: Regardless of central shielding after 44-45 Gy whole pelvis irradiation, more patients with high external parametrial dose developed radiation proctitis. Incomplete midline shielding of the upper rectum may be the cause. Diminishing the external beam doses further may decrease rectal complications.

Adult↗

PubMed2000

High-Resolution Study of the First Hexad of D(2)O.

The high-resolution Fourier transform spectra of the D(2)O molecule have been recorded and assigned in the 4200-5700 cm(-1) region where the vibration-rotation bands 2nu(1), 2nu(3), nu(1) + nu(3), nu(1) + 2nu(2), 2nu(2) + nu(3), and 4nu(2) are located. The presence of numerous and very strong accidental perturbations between the states of the hexad makes it necessary to take into account not only ordinary resonance interactions of the Fermi, Darling-Dennison, and/or Coriolis types, but interactions between the states (v(1)v(2)v(3)) and (v(1) -/+ 2v(2) +/- 2v(3) +/- 1) as well. Parameters of all six vibrational states of the hexad were obtained from the fit of experimental energy values. Copyright 2000 Academic Press.

Journal Article↗

PubMed2000

High-Resolution Fourier Transform Spectrum of the D(2)O Molecule in the Region of the Second Triad of Interacting Vibrational States.

The high-resolution Fourier transform spectrum of the D(2)O molecule was recorded in the 3200-4200 cm(-1) region, where the bands of the second triad of interacting vibrational states are located. As a result of the theoretical analysis, both the rotational-vibrational structure of the (011) vibrational state was improved, and the rotational energies of the (110) and (030) vibrational states were determined for the first time up to rotational quantum numbers J(max.) = 15 and 14, respectively. Copyright 2000 Academic Press.

Journal Article↗

PubMed2000

High-Resolution Study of Strongly Interacting Vibrational Bands of HDO in the Region 7600-8100 cm(-1).

The high-resolution Fourier transform spectrum of the HDO molecule was recorded and analyzed in the region 7600-8100 cm(-1) where the weak vibration-rotation bands 3nu(1) and nu(1) + nu(2) + nu(3) are located. Because of the presence of strong local resonance interactions, transitions belonging to the 3nu(2) + nu(3) and 6nu(2) bands were assigned as well. Spectroscopic parameters of all four bands were estimated, which reproduce initial line positions with accuracy close to experimental uncertainties. Copyright 2000 Academic Press.

Journal Article↗

PubMed2000

High-Resolution Study of the (v(1) + 12v(2) + v(3) = 3) Polyad of Strongly Interacting Vibrational Bands of D(2)O.

Analysis of the high-resolution Fourier transform spectra of the D(2)O first decade was carried out in the framework of the Hamiltonian model which took into account resonance interactions between the seven states, (300), (201), (102), (003), (220), (121), and (022). Assigned from the experimentally recorded spectrum transitions belonged to the four bands, 2nu(1) + nu(3), 3nu(3), nu(1) + 2nu(2) + nu(3), and 3nu(1), gave the possibility both of obtaining rotational, centrifugal distortion, and resonance interaction parameters of "appeared" states, (201), (003), (121), and (300), and of estimating from the fit band centers, rotational, and resonance interaction parameters of the three "dark" states, (220), (022), and (102). Copyright 2000 Academic Press.

Journal Article↗

PubMed2000

Adhesive events in retinal development and function: the role of integrin receptors.

Cells in the developing retina contact a vast array of molecular cues in their microenvironment that are thought to guide their development. Many of these cues are embedded in the surface of neighboring cells or deposited within the extracellular matrix (ECM). Evidence has accumulated that cell-cell and cell-ECM interactions are essential in many phases of neural development, including neuroblast migration, determination of cell fate, axon outgrowth and synapse formation. In this chapter, we examine the developmental and functional roles fulfilled by integrins, a family of receptors for ECM molecules and cell adhesion molecules (CAMs). We have approached this problem by addressing a series of three questions: (1) which integrins are expressed in developing retina? (2) when and where are they expressed? and, (3) what functions do they carry out? Integrins have previously been implicated in axon extension, but new evidence suggests that they are also involved in earlier developmental events in preaxonal neuroblasts. High levels of expression of at least eight integrin subunits have been documented in these young retinal cells, and integrins containing the beta 1 subunit have been implicated in migration of adolescent retinal ganglion cells. Integrin expression persists through adulthood, both in the retina and in the neighboring layer of the retinal pigment epithelium (RPE). The integrin alpha v beta 5 has been shown to reside on the apical surface of the RPE and has been implicated in the phagocytosis of shed photoreceptor outer segments.

Animals↗

PubMed2000

The role of radical surgery followed by adjuvant therapy for high-risk early-stage cervical carcinoma patients with pelvic lymph node metastasis.

OBJECTIVES: To identify a subgroup of high-risk node-positive patients in early-stage cervical cancers and to determine the role of radical hysterectomy followed by adjuvant therapy to these patients. STUDY DESIGN: We conducted a retrospective review of 482 surgically-treated patients of clinical stage Ib and IIa cervical carcinoma from July 1986 to December 1994 at Kaohsiung Chang Gung Memorial Hospital. Of these, 96 patients had pelvic lymph node metastases. Clinicopathological variables, including the level of pretreatment squamous cell carcinoma antigen (SCC-Ag), DNA flow cytometry analysis, and the use of different adjuvant therapies were studied. RESULTS: Disease-free survival was significantly worse among patients with S-phase fraction greater than 20% and pretreatment SCC-Ag level above 5 ng/ml. Utilizing these significant variables, we identified two distinct risk groups. Those patients without any of the risk variables were categorized as the low-risk group. Those patients with either one or both risk variables were categorized as the high-risk group. Five-year disease-free survival rates were 74% in the low-risk group and 43% in the high-risk group, (P=0.034). Disease recurred in 30.2% of the low-risk patients and 45. 3% of the high-risk patients. No survival advantages were found by using different adjuvant therapies. CONCLUSIONS: Radical hysterectomy should not be attempted if either the pretreatment SCC-Ag level is above 5 ng/ml or S-phase fraction of the tumor greater than 20% due to its limited value despite applying aggressive postoperative adjuvant therapy.

Adenocarcinoma↗

PubMed2000

High potassium intake inhibits neointima formation in the rat carotid artery balloon injury model.

Recently, we reported that elevated extracellular potassium concentration in vitro inhibited proliferation and migration of vascular smooth muscle cells, formation of free radical compounds by macrophages, and reduced platelet sensitivity to agonists. In the present study we analyzed the effects of long-term, in vivo elevation of extracellular potassium concentration resulting from changes in dietary potassium intake on the vascular response to injury. The rat carotid artery balloon injury model was employed in 70 adult Sprague Dawley rats assigned to three groups. Beginning 14 days before surgical placement of the carotid lesion and continuing until death, the animals were fed diets containing either low (0.1% potassium, n = 25), normal (1.5% potassium, n = 19), or high potassium (4.0% potassium, n = 26). Fourteen days postsurgery the animals were killed and the arteries were analyzed to determine quantitatively the ratio of neointimal to medial area. Dietary potassium had a significant effect on arterial plasma potassium concentration (one-way analysis of variance, P < .01). Group mean and standard errors were 4.26+/-0.12 mmol/L for the low-potassium group, 5.22+/-0.19 mmol/L for normal, and 5.80+/-0.23 mmol/L for the high-intake group. Increases in dietary potassium attenuated neointima formation significantly (P < .05, one-way analysis of variance), with the mean ratio of neointimal area to medial area being 0.447+/-0.106 for the low-intake animals, 0.384+/-.116 for normal, and 0.240+/-.046 for the high-intake group. These results are consistent with a hypothesis that a high level of potassium intake is effective in inhibiting neointima formation in vivo.

Animals↗

PubMed2000

The role of pretreatment squamous cell carcinoma antigen in predicting nodal metastasis in early stage cervical cancer.

PURPOSE: To evaluate whether the presence of pelvic lymph node metastasis can be predicted by pretreatment squamous cell carcinoma antigen (SCC-Ag) levels in early stage squamous cervical carcinoma. MATERIALS AND METHODS: Between 1994 and 1998, 284 patients with stage Ib and IIa cervical squamous cell carcinoma undergoing radical hysterectomy had preoperative SCC-Ag determination. The correlation between clinicopathological findings on SCC-Ag levels were examined. The Mann-Whitney U test was used to statistically analyze differences between node positive and negative patients. Multiple regression analysis and a multiple logistic model were employed to examine the effect of clinicopathological findings on SCC-Ag levels. RESULTS: Of the 284 patients, 56 patients were found to have nodal metastasis. Median serum levels and 90% ranges of SCC-Ag were 0.74 microg/l (0.5-7.8) in the 228 nodal negative patients and 4.33 microg/l (0.5-48.5) in the 56 nodal positive patients (p<0.001). Lymph node metastasis and tumor size were found to have a significant impact on SCC-Ag levels. Around 86% of the patients with SCC-Ag levels below 8 microg/l showed no nodal metastasis, while about 65% of the patients with serum levels above 8 microg/l exhibited nodal metastasis. Multivariate analyses confirmed that only lymph node metastasis had a significant impact on the SCC-Ag levels exceeding 8 microg/l. CONCLUSION: For predicting nodal metastasis preoperatively, SCC-Ag levels greater than 8 microg/ l can be considered a high-risk zone for nodal metastasis.

Antigens, Neoplasm↗

PubMed2000

A syndrome of tricuspid atresia in mice with a targeted mutation of the gene encoding Fog-2.

Tricuspid atresia (TA) is a common form of congenital heart disease, accounting for 1-3% of congenital cardiac disorders. TA is characterized by the congenital agenesis of the tricuspid valve connecting the right atrium to the right ventricle and both an atrial septal defect (ASD) and a ventricular septal defect (VSD). Some patients also have pulmonic stenosis, persistence of a left-sided superior vena cava or transposition of the great arteries. Most cases of TA are sporadic, but familial occurrences with disease in multiple siblings have been reported. Gata4 is a zinc-finger transcription factor with a role in early cardiac development. Gata4-deficient mice fail to form a ventral heart tube and die of circulatory failure at embryonic day (E) 8.5 (refs 6,7). Zfpm2 (also known as Fog-2) is a multi-zinc-finger protein that is co-expressed with Gata4 in the developing heart beginning at E8.5 (refs 8-10). Zfpm2 interacts specifically with the N-terminal zinc finger of Gata4 and represses Gata4-dependent transcription. Here we use targeted mutagenesis to explore the role of Zfpm2 in normal cardiac development. Zfpm2-deficient mice died of congestive heart failure at E13 with a syndrome of tricuspid atresia that includes an absent tricuspid valve, a large ASD, a VSD, an elongated left ventricular outflow tract, rightward displacement of the aortic valve and pulmonic stenosis. These mice also display hypoplasia of the compact zone of the left ventricle. Our findings indicate the importance of Zfpm2 in the normal looping and septation of the heart and suggest a genetic basis for the syndrome of tricuspid atresia.

Animals↗

PubMed2000

Direct effects of propylthiouracil on testosterone secretion in rat testicular interstitial cells.

The aim of this study was to investigate the mechanism by which propylthiouracil (PTU) exerts its inhibitory effects on the production of testosterone by rat testicular interstitial cells. The plasma testosterone concentration was decreased 60 and 120 min after an intravenous infusion of PTU (10 or 20 mg kg(-1)), but the concentration of plasma T(4) was unaffected by the drug treatment. Exposure of anterior pituitary tissue to PTU (3-12 mM) in vitro did not affect either basal or gonadotropin-releasing hormone (GnRH)-stimulated luteinizing hormone (LH) release. PTU (3 - 12 mM) inhibited both the basal and the human chorionic gonadotropin (hCG, 0.05 i.u. ml(-1))-stimulated release of testosterone from rat testicular tissue in vitro; at the highest concentration tested (12 mM), it also inhibited the forskolin or 8-bromo-adenosine 3':5'-cyclic monophosphate (8-Br-cyclic AMP)-stimulated release of testosterone. The 25-OH-cholesterol (10(-7)-10(-5) M)-stimulated release of pregnenolone and testosterone by the testicular interstitial cells was inhibited by PTU (12 mM, P<0.05). The results suggest that the inhibitory actions of PTU on testosterone secretion are exerted, at least in part, at the testicular level through a mechanism which is independent of thyroid status and which involves a reduction in P450scc activity and, hence, in the conversion of cholesterol to pregnenolone.

Animals↗

PubMed2000

Measuring diet quality in china: the INFH-UNC-CH diet quality index.

OBJECTIVE: This paper describes the development and efficacy of a diet quality index (DQI) for China. DESIGN: The Dietary Guidelines for Chinese Residents motivated the selection of 10 DQI components. These components were weighted and assigned cut-offs and point schemes based on the Chinese Food Guide Pagoda, Chinese and/or international dietary reference values. The efficacy of resulting DQI scores was assessed relative to a priori expectations. SUBJECTS: The Chinese DQI was evaluated using cross-sectional 3 day diet record and anthropometric data on 7450 adults from the 1991 China Health and Nutrition Survey. METHODS: For each individual, a DQI total score was calculated as the sum of components, and DQI pattern scores calculated to reflect the underlying composition of diet quality problems. The DQI scores were compared with component scores, food and nutrient intake, weight status and sociodemographic variables. RESULTS: The total DQI score simultaneously represented all component aspects of diet quality as well as micronutrients not explicitly built into the index. The total DQI score was significantly correlated with food and nutrient intakes, BMI, urban residence and income. The DQI pattern scores correlated with DQI components and weight status as expected. CONCLUSIONS: The China DQI captures variation along several components of diet quality, appears sensitive to under- and overnutrition, as well as sociodemographic variables. The China DQI may prove useful for monitoring the nutrition transition and epidemiologic trends in China. SPONSORSHIP: National Institutes of Health (HD 38700 and R01-HD30880) and the Chinese Academy of Preventive Medicine.

Adult↗

PubMed2000

Outcome of preterm infants with congenital heart disease.

OBJECTIVES AND STUDY DESIGN: To evaluate the morbidity and mortality of preterm infants with congenital heart disease (CHD), a chart review was performed for infants with CHD, excluding isolated patent ductus arteriosus, who were <37 weeks' gestation, weighed <2500 g, and were admitted to our neonatal intensive care unit from 1976 to 1999 (N = 201). RESULTS: Patients in the study represented 1.9% of the total neonatal intensive care unit population <37 weeks' gestation and <2500 g. The median gestational age was 33 weeks, and the mean birth weight was 1852 g. CHD diagnosis frequencies were similar to those reported in other large incidence studies, except for a higher percentage of conotruncal defects. The risk of necrotizing enterocolitis was 1.7 times higher and the overall mortality twice as high in our patients compared with patients in the neonatal intensive care unit who did not have CHD. Cardiac surgery (n = 133) was performed on 108 patients. During the recent period of 1985 to 1999, compared with our institution's overall results for CHD surgery, the operative mortality rate was 10.4% versus 5.4% for closed procedures and 25.4% versus 10.5% for open procedures. The actuarial survival rate is 51% at 10 years; survival improved as the study period progressed. CONCLUSIONS: Infants with both CHD and prematurity did significantly worse than either group alone. Such outcome data are required for proper allocation of resources to care for this high-risk pediatric population.

Cardiac Surgical Procedures↗

PubMed2000

Identification of heading date quantitative trait locus Hd6 and characterization of its epistatic interactions with Hd2 in rice using advanced backcross progeny.

A backcrossed population (BC(4)F(2)) derived from a cross between a japonica rice variety, Nipponbare, as the recurrent parent and an indica rice variety, Kasalath, as the donor parent showed a long-range variation in days to heading. Quantitative trait loci (QTL) analysis revealed that two QTL, one on chromosome 3, designated Hd6, and another on chromosome 2, designated Hd7, were involved in this variation; and Hd6 was precisely mapped as a single Mendelian factor by using progeny testing (BC(4)F(3)). The nearly isogenic line with QTL (QTL-NIL) that carries the chromosomal segment from Kasalath for the Hd6 region in Nipponbare's genetic background was developed by marker-assisted selection. In a day-length treatment test, the QTL-NIL for Hd6 prominently increased days to heading under a 13.5-hr day length compared with the recurrent parent, Nipponbare, suggesting that Hd6 controls photoperiod sensitivity. QTL analysis of the F(2) population derived from a cross between the QTL-NILs revealed existence of an epistatic interaction between Hd2, which is one of the photoperiod sensitivity genes detected in a previous analysis, and Hd6. The day-length treatment tests of these QTL-NILs, including the line introgressing both Hd2 and Hd6, also indicated an epistatic interaction for photoperiod sensitivity between them.

Chromosome Mapping↗