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Biomedical subjects

H J Lin

Publications and source records attributed to H J Lin.

At least 55 records · Page 3Linked to original sources
PubMed1999

Lifetime-based pH sensors: indicators for acidic environments.

We characterized the pH-dependent intensity decays of three fluorophores, Oregon green 514 carboxylic acid, Cl-NERF, and DM-NERF, using frequency-domain fluorometry, with the objective of identifying lifetime-based sensors for low pH values. These three probes were originally designed as dual excitation wavelength-ratiometric probes, with high photostability and high quantum yields in aqueous solutions. We found that their fluorescence intensity decays were strongly dependent on pH. Moreover, global intensity decays analysis reveals that these probes have double exponential intensity decays at intermediate pH values and that the decay time amplitudes are greatly dependent on pH. The longer lifetime components originated from the unprotonated forms and the shorter components from the protonated forms. Both forms can emit fluorescence at intermediate pH values. The apparent pKa values were also determined from the titration curves of phase angles and modulations versus pH for the purpose of pH sensing. The apparent pKa values range from pH 3 to 5, a range where lifetime-based sensors are not presently reported. Since these probes show low pKa values and display substantial phase and modulation changes with pH, they are suitable as lifetime-based pH sensors to monitor the pH changes in acidic environments. One potential application of these probes is to trace the pH in different cellular compartments.

Fluoresceins↗
PubMed1999

Intrachromosomal triplication of 2q11.2-q21 in a severely malformed infant: case report and review of triplications and their possible mechanism.

A female fetus with brain malformations, multicystic kidneys, absence of the right thumb, and a posterior cleft of palate was delivered at 32 weeks of gestation. Cytogenetic studies including FISH showed a novel intrachromosomal triplication of the proximal long arm of chromosome 2 (q11.2-q21), resulting in tetrasomy for this segment. The middle repeat was inverted. At least 11 patients with intrachromosomal triplications have been reported, mostly involving chromosome 15q. The mechanism involved in formation of these rearrangements is compatible with U-type exchange events among three chromatids.

Abnormalities, Multiple↗
PubMed1999

Negative CLOtest pellet can be reused.

BACKGROUND: The CLOtest is based on the production of ammonia from urea in the presence of urease. In theory, substrate that has not been consumed in a negative test can be reused. METHODS: We collected negative CLOtest pellets after their first use and stored them at room temperature. Whenever a CLOtest was needed during endoscopy, two biopsy specimens were taken from the antrum. One specimen was tested with a new CLOtest and the other with one that had been used previously. Time to color change was observed in paired tests. RESULTS: We used 216 previously used CLOtest pellets with biopsy specimens obtained from 317 patients. Of the paired tests, 204 matched positive and 108 tested negative. Only 5 paired tests had discrepant results. Three had positive results only with a new CLOtest, and 2 were positive only with the reused test. In positive paired tests, there was significant linear correlation in log-transformed color change time between reused and new tests (p < 0.001). Ninety-two percent of previously used pellets were reused fewer than three times before they yielded a positive color change; the interval to this occurrence ranged from 2 to 15 days. Compared with the new CLOtest, the sensitivity of the reused CLOtest was 98. 6% and the specificity was 98.2%. CONCLUSIONS: A negative CLOtest kept at room temperature can be reused within a short period of time, in circumstances in which there are environmental and economic considerations to be taken into account.

Biopsy↗
PubMed1999

Will Helicobacter pylori affect short-term rebleeding rate in peptic ulcer bleeding patients after successful endoscopic therapy?

OBJECTIVE: Helicobacter pylori (H. pylori) can augment the pH-increasing effect of omeprazole in patients with peptic ulcer. A high intragastric pH may be helpful in preventing recurrent hemorrhage by stabilizing the blood clot at the ulcer base of bleeding peptic ulcer patients. Therefore, we hypothesized that omeprazole may reduce short-term rebleeding rate in these patients with H. pylori infection after initial hemostasis had been obtained. METHODS: Between July 1996 and December 1998, 65 bleeding peptic ulcer patients (24 gastric ulcer, 41 duodenal ulcer) who had obtained initial hemostasis with endoscopic therapy were enrolled in this trial. Thirty (46.2%) of them were found to have H. pylori infection by a rapid urease test and pathological examination. For all studied patients, omeprazole was given 40 mg intravenously every 6 h for 3 days. Thereafter, omeprazole was given 20 mg per os (p.o.) once daily for 2 months. A pH meter was inserted in the fundus of each patient under fluoroscopic guidance after intravenous omeprazole had been administered. The occurrence of rebleeding episode was observed for 14 days. RESULTS: In patients with H. pylori infection, intragastric pH (median, 95% confidence interval [CI]: 6.54, 5.90-6.68) was higher than in those without H. pylori infection (6.05, 5.59-6.50, p < 0.001). However, the patients with rebleeding (2 vs 3), volume of blood transfusion (median, range: 1000 ml, 0-2250 vs 750, 0-2000), number of operations (0 vs 1), mortality caused by bleeding (0 vs 0), and hospital stay (median, range: 6 days, 3-14 vs 7, 5-16) were not statistically different from those without H. pylori infection. CONCLUSIONS: Omeprazole does increase intragastric pH in bleeding peptic ulcer patients with H. pylori infection. However, the presence of H. pylori infection does not affect the short-term rebleeding rate in these patients.

Adult↗
PubMed1999

Comparison of adrenaline injection and bipolar electrocoagulation for the arrest of peptic ulcer bleeding.

BACKGROUND: Peptic ulcers with active bleeding or a non-bleeding visible vessel require aggressive endoscopic treatment. AIMS: To determine whether endoscopic adrenaline injection alone or contact probe therapy following injection is a suitable treatment for peptic ulcer bleeding. METHODS: A total of 96 patients with active bleeding or non-bleeding visible vessels received adrenaline alone, bipolar electrocoagulation alone, or combined treatment (n=32 in each group). RESULTS: Initial haemostasis was not achieved in one patient in the adrenaline group, two in the gold probe group, and two in the injection gold probe group (p>0.1). Rebleeding episodes were fewer in the injection gold probe group (2/30, 6.7%) than in the gold probe group (9/30, 30%, p=0.04) and in the adrenaline group (11/31, 35.5%, p=0.01). Treatment failure (other therapy required) was rarer in the injection gold probe group (4/32, 12.5%) than in the adrenaline group (12/32, 37.5%, p=0.04). The volume of blood transfused after entry of the study was less in the injection gold probe group (mean 491 ml) than in the adrenaline group (1548 ml, p<0. 0001) and the gold probe group (1105 ml, p<0.01). Duration of hospital stay, numbers of patients requiring urgent surgery, and death rate were not statistically different among the three groups. CONCLUSIONS: For patients with peptic ulcer bleeding, combined adrenaline injection and gold probe treatment offers an advantage in preventing rebleeding and decreasing the need for blood transfusion.

Adolescent↗
PubMed1999

Expression and mutation analysis of the p53 gene in astrocytoma.

The role of p53 gene mutations in the formation or progression of human astrocytic tumors is controversial. We studied the distribution pattern of p53 immunoreactivity and analyzed p53 gene mutations to define the significance of p53 gene mutations in astrocytoma tumorigenesis or malignant progression. Twenty-three astrocytic tumors were evaluated with immunohistochemistry, single-strand conformation polymorphism (SSCP) analysis, and sequence analysis. We also searched MEDLINE to collect data on p53 gene mutation frequencies in astrocytic tumors in order to evaluate the association of p53 mutations and tumor grade. Strong immunoreactivity with a diffuse clustering pattern was found in three of five glioblastomas and seven of 12 anaplastic astrocytomas. Three of four low-grade astrocytomas were immunonegative. The p53 immunopositive cells in the only positively staining low-grade astrocytoma in our study appeared sparsely scattered. The results of immunostaining suggested that clonal expansion was associated with astrocytoma progression. Mutations of the p53 gene were detected in four of the 23 astrocytomas (one glioblastoma and three anaplastic astrocytomas). In the genetic data analysis, 76 of 367 astrocytomas had p53 gene mutations. A significantly greater p53 gene mutation frequency was found in anaplastic astrocytomas or glioblastomas than in the low-grade astrocytomas. The results of these immunohistochemical and genetic studies support the view that p53 gene mutation is associated with the malignant progression from low-grade to high-grade astrocytomas rather than with tumor initiation or promotion.

Adolescent↗
PubMed1999

Analysis of referral initiatives, severity of illness and return to care of older women with cervical cancer.

BACKGROUND: Cervical cancer is a worldwide malignancy particularly prevalent in older women. Due to the increasing population ratio of older women and their more complicated illnesses, doctors in Taiwan are concerned about the care of older patients with cervical cancer. Few studies have been performed on the association between referral initiative and illness severity upon referral as well as the tendency of older patients with cervical cancer to return to the referring doctor and to the consultant at the medical center for follow-up. The purpose of this study was to investigate the referral association by adjusting for confounding variables. METHODS: This study included 214 women aged 65 years and over with cervical cancer diagnosed between 1987 and 1995. Patients were referred to a tertiary teaching hospital by 71 primary care gynecologists. The International Federation of Gynecology and Obstetrics clinical stage and clinical severity were assessed in each patient. Histopathologic results were reviewed to confirm the diagnosis. RESULTS: Of all the cervical cancer referrals, 20.2% were initiated by patients or families and 79.8% were initiated by primary care doctors. No statistically significant differences were found in the Basic Activities of Daily Living or Instrumental Activities of Daily Living between doctor- and patient-initiated referrals. High Geriatric Depression Scale and low Mini-Mental State Examination were associated with doctor-initiated referrals. Higher cancer stage and greater clinical severity of patients with cervical cancer was found in patient- rather than doctor-initiated referrals. After adjusting for marriage, family type, medical payment, mental status, cancer stage and clinical severity, the data showed that, if the referral was initiated by a primary care doctor, older patients with cervical cancer had a similar likelihood to return to both the primary care doctor and the tertiary teaching hospital for follow-up. CONCLUSIONS: If a referral was initiated by a doctor, older women with cervical cancer were not only likely to return to their consulting physician at the medical center, but also likely to return to their primary care doctor. Continuous care is more likely to occur when the primary care doctor initiated the referral.

Aged↗
PubMed1999

Influence of Helicobacter pylori on gastric secretion and gastrin release in normal Chinese subjects.

BACKGROUND: Controversy exists concerning the influence of Helicobacter pylori on gastric secretion. Hyper-, normo- and hyposecretion of gastric acid in normal subjects with H pylori infection have been reported, although there is no such report for Chinese subjects. The goal of this study was to identify the effect of H pylori on gastric secretion in normal Chinese subjects. METHODS: Twenty normal subjects with a normal upper gastrointestinal tract by endoscopy were recruited. H pylori status was assayed by a rapid urease test. Gastric secretion and gastrin release were also measured. RESULTS: Among the subjects studied, nine were infected with H pylori. All enrolled subjects were males. Age and body weight were similar between both groups. No significant difference was found in basal acid output, maximal acid output, basal pepsin output or maximal pepsin output between the H pylori-positive group (median, 1.1 mmol/hour, 95% confidence interval 0.2-3.6 mmol/hour; 8.0, 3.0-18.3 mmol/hour; 0, -1.3-11.2 mmol/hour; and 4.1, -4.2-59.3 mmol/hour, respectively) and the H pylori-negative group (2.5, -1.3-11.3 mmol/hour; 12.2, 8.7-26.9 mmol/hour; 4.3, 1.8-13.5 mmol/hour; and 14.8, -5.7-73.0 mmol/hour, respectively). Serum basal gastrin and pepsinogen I concentration were 63.5, 50.0-78.6 pg/ml and 75.1, 50.6-89.8 ng/ml in the H pylori-positive group, and 65.9, 50.2-79.8 pg/ml and 79.1, 59.5-120.1 ng/ml in the H pylori-negative group (p > 0.05). CONCLUSIONS: H pylori plays no role in the gastric secretion and gastrin release in normal Chinese subjects.

Aged↗
PubMed1999

AO fixateur interne in treating burst fractures of the thoracolumbar spine.

BACKGROUND: A burst fracture of the thoracolumbar junction is an unstable spinal fracture, which is caused by high-energy trauma. There are many methods of treatment, both surgical and nonsurgical, in dealing with spinal burst fractures. The Arbeitsgemeinschaft für Osteosynthesefragen (AO) Fixateur Interne (FI) system was introduced in 1985 for posterior spine surgery with a transpedicular screw system. METHODS: From April, 1989, through December, 1994, we encountered 42 patients with 42 acute burst fractures of the spine; 26 were male and 16 were female, with an average age of 41.2 years. One fracture occurred on T11, seven on T12, 16 on L1, 11 on L2, one on L3, four on L4 and two on L5. According to the Denis classification, there were eight type A, 23 type B, five type C, three type D and three type E fractures. All of these patients received posterior reduction without decompression, posterior short segmental fixation with AO FI instrumentation and posterior fusion. RESULTS: After follow-up for an average of 66.1 months, all fractures were found to have united with residual back pain in only six patients; five patients, including one with nonunion, had back pain without the necessity of medication, and the other one had occasional back pain that was well controlled by medication. The immediate postoperative Cobb's angle improved by an average of 14.2 degrees, and there was an average loss of 3.3 degrees at final follow-up. All patients were neurologically intact at final follow-up except two patients, who were Frankel D. Seven patients had complications during follow-up; one experienced nonunion; four experienced screw breakage, one had screw pullout, and the other experienced breakage of the connecting rod. CONCLUSIONS: From our retrospective study, the outcome of burst fracture of the spine treated with AO FI instrumentation system was satisfactory.

Adult↗
PubMed1998

Selection of appropriate HIV-1 genomic regions for single-strand conformation polymorphism analysis of the diversity, modification, and transmission of HIV-1 quasispecies.

Single-strand conformation polymorphism (SSCP) analysis is a useful tool for studying viral quasispecies. Four regions within the HIV-1 genome were studied by means of SSCP analysis with the aim of determining which regions were the most informative for the study of HIV-1 transmission or for detection of changes in HIV-1 quasispecies populations. Nested polymerase chain reaction (PCR) was used to amplify V1, V2, V3 of the env gene, and the p2 region in the gag gene. In total, 114 plasma specimens from 79 individuals were tested, including serial specimens from 10 mother-infant pairs that were provided by the Women and Infants Transmission Study (WITS). HIV-1 in specimens that were PCR-positive with primer pair SK38/SK39 showed different percentages of positive signals with primer pairs for the four regions: V1, 63%; V2, 83%; V3, 88%, and p2, 100%. HIV-1 sequences in the p2 target region displayed the greatest degree of polymorphism. Analysis of serial specimens showed that the V1 target region was the most variable of the four regions studied and was the most appropriate region for monitoring changes in quasispecies populations. Of the four regions studied, p2 was the most informative for the study of HIV transmission, as shown by analysis of samples from documented cases of mother to infant HIV-1 transmission.

Female↗
PubMed1998

Omphalocele with absent radial ray (ORR): a case with diploid-triploid mixoploidy.

We observed omphalocele, absence of radii, hypoplasia of one humerus, a hemivertebra, and syndactyly in a stillborn male at 22 weeks of gestation. Craniofacial and genitourinary abnormalities were absent. DNA measurement by flow cytometry on a paraffin-embedded autopsy specimen showed 32% triploid cells. ORR (omphalocele-radial ray) complex appears to be a consistent combination, and diploid-triploid mixoploidy may be one of its causes.

Abnormalities, Multiple↗
PubMed1998

A prospective randomized comparative trial showing that omeprazole prevents rebleeding in patients with bleeding peptic ulcer after successful endoscopic therapy.

BACKGROUND: A blood clot in a peptic ulcer is unstable in a low pH environment. The use of omeprazole may prevent rebleeding by elevating intragastric pH in patients with bleeding peptic ulcer after hemostasis has been achieved. OBJECTIVES: To assess the influence of using omeprazole and cimetidine on 24-hour intragastric pH and to determine their ability to prevent rebleeding after having achieved initial hemostasis in patients with active bleeding or nonbleeding visible vessels. METHODS: One hundred patients with bleeding peptic ulcers who had obtained initial hemostasis were enrolled in this randomized comparative trial. In the cimetidine group (n = 50), a 300-mg intravenous bolus of cimetidine was given, followed by a 1200-mg continuous infusion daily for 3 days. Thereafter, 400 mg of cimetidine was given orally twice daily for 2 months. In the omeprazole group (n = 50), a 40-mg intravenous bolus of omeprazole was given, followed by 160 mg of continuous infusion daily for 3 days. Thereafter, 20 mg of omeprazole was given orally once daily for 2 months. A pH meter was inserted in each patient's fundus under fluoroscopic guidance after the intravenous bolus of cimetidine or omeprazole had been administered. RESULTS: The stigmata of recent hemorrhage before endoscopic therapy in the omeprazole and cimetidine groups were, respectively, spurting (9 vs 12), oozing (4 vs 9), and nonbleeding visible vessel (37 vs 29) (P > .05). The duration of intragastric pH higher than 6.0 was longer in the omeprazole group (mean [+/- SD], 84.4% +/- 22.9%) than that of the cimetidine group (mean [+/- SD], 53.5% +/- 32.3%) (P < .001). Rebleeding occurred in 2 patients (4%) in the omeprazole group and in 12 patients (24%) in the cimetidine group by day 14 after enrollment (P = .004). There was a tendency for patients in the omeprazole group to require less blood transfusion (median, 0 mL; range, 0-2500 mL) than those in the cimetidine group (median, 0 mL; range, 0-5000 mL) (P = .08). The hospital stay and number of operations and mortality rate were similar between both groups. CONCLUSIONS: The use of omeprazole is more effective than cimetidine in increasing intragastric pH and reducing rebleeding episodes in patients with bleeding peptic ulcers after successful endoscopic therapy. This suggests that omeprazole should be used routinely after successful endoscopic therapy.

Adolescent↗
PubMed1998

Anomalous inferior and superior venae cavae with oculoauriculovertebral defect: review of Goldenhar complex and malformations of left-right asymmetry.

We observed a girl with an interrupted, left inferior vena cava with hemiazygous continuation, bilateral superior venae cavae, heart defects, and sacral agenesis. She had macrostomia and bilateral ear tags and pits, as in oculoauriculovertebral defect. Maternal diabetes was present. The combination, which we call OAV-heterotaxia complex, supports the view that some cases of oculoauriculovertebral defect may be part of a midline field defect of blastogenesis.

Female↗
PubMed1998

Chronic administration of octreotide ameliorates portal hypertension and portal hypertensive gastropathy in rats with cirrhosis.

1. Portal hypertension and hyperdynamic circulation have been postulated to play a role in the pathogenesis of portal hypertensive gastropathy. Administration of octreotide to portal hypertensive rats has been shown to reduce portal pressure and ameliorate hyperdynamic circulation. 2. This study investigated the effects of chronic administration of octreotide on systemic and portal haemodynamics and the development of portal hypertensive gastropathy in carbon tetrachloride-induced cirrhotic rats. 3. After 12 weeks of carbon tetrachloride induction, cirrhotic rats were randomly assigned to receive either placebo (5% dextrose in water) or octreotide (65 micrograms/kg in 5% dextrose in water) subcutaneously twice daily for 10 days. Haemodynamic studies with a thermodilution technique and gastric morphometric analyses were performed at 10 days after treatment. 4. In cirrhotic rats, octreotide treatment induced a significant increase in systemic vascular resistance (2.7 +/- 0.2 versus 3.4 +/- 0.2 mmHg/ml.min-1.100 g-1, P < 0.05) and decrease in portal pressure (12.5 +/- 1.2 versus 9.9 +/- 0.5 mmHg, P < 0.05) compared with placebo-treated rats. In addition, octreotide treatment significantly reduced the mean cross-sectional area of gastric mucosal vessels (2290 +/- 145 versus 1810 +/- 101 micron 2, P < 0.05). 5. This study shows that chronic octreotide treatment ameliorates the development of portal hypertensive gastropathy in cirrhotic rats. The effect of octreotide on portal hypertensive gastropathy may, at least partly, be due to the alleviation of portal hypertension and hyperdynamic circulation.

Animals↗