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Biomedical subjects

C H Lu

Publications and source records attributed to C H Lu.

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

Acinetobacter meningitis: four nosocomial cases.

We report the clinical features and therapeutic outcomes of four patients with multiantibiotic-resistant Acinetobacter meningitis. There were three males and one female, aged from 17 to 49 years. Three of them had suffered from head injuries with skull fractures, and the other suffered from an intracerebral hemorrhage and underwent a craniotomy. All four patients acquired nosocomial Acinetobacter meningitis, and multiantibiotic resistance developed. After treatment with imipenem/cilastatin, three of the four patients survived; one died of multiorgan failure. Because the clinical manifestations of Acinetobacter meningitis are similar to those of other gram-negative bacillary meningitis, the diagnosis can only be confirmed by bacterial culture. Resistance to multiple antibiotics, including third-generation cephalosporins, is frequently seen in patients with nosocomial Acinetobacter meningitis, and imipenem/cilastatin seems to be the antibiotic of choice for this potentially fatal central nervous system infection.

Acinetobacter Infections↗
PubMed1999

Pseudomonas aeruginosa central nervous system infections: analysis of clinical features of 16 adult patients.

BACKGROUND: The purpose of this study was to analyze the clinical features and therapeutic outcome of 16 adult patients with Pseudomonas aeruginosa central nervous system (CNS) infection. We also attempted to identify the factors that significantly influence the prognosis of this potentially fatal CNS infection. METHODS: Sixteen adult patients with P aeruginosa CNS infection, nine men and seven women, aged from 18 to 86 years, were included in this retrospective study. The clinical features and the laboratory data of these patients were analyzed. Potential prognostic factors were compared by means of Fisher's exact test and the relative risks were estimated by odds ratio. RESULTS: Of the 16 patients, 13 had meningitis and three had focal suppuration (two with brain abscess and one with spinal epidural abscess). The 13 meningitis patients with nosocomial or community-acquired infections were classified into two forms: the spontaneous form and the neurosurgical form. The overall mortality rate was 37.5% (6/16). In the meningitis group, the patients with the neurosurgical form had a lower mortality rate (11.1%; 1/9) than the patients with the spontaneous form (100%; 4/4), and those with community-acquired meningitis had a higher mortality rate (80%; 4/5) than those with nosocomial infections (12.5%; 1/8). All the meningitis patients who did not receive appropriate antibiotic treatment expired. The statistically significant prognostic factors included the acquisition of infection, form of infection, bacteremia, initial level of consciousness and the use of appropriate antibiotics. CONCLUSIONS: Vigilance for P aeruginosa is particularly important in patients with predisposing factors such as head injury, neurosurgical procedures and long-term debilitating diseases. Early appropriate antibiotic therapy and neurosurgical intervention for patients with suppurative infections can bring about improved therapeutic results.

Adolescent↗
PubMed1999

Transmyocardial holmium-YAG laser channels in an animal model: a preliminary morphologic and histologic study.

BACKGROUND: Laser transmyocardial revascularization (TMR) appears to improve symptoms in patients with refractory angina. However, it remains a controversial treatment modality for relieving ischemia. We conducted our study in dogs and evaluated the changes in morphology and histology of the myocardium after laser TMR. METHODS: The hearts of 10 mongrel dogs (20-30 kg each) were treated with a holmiumyttrium aluminum garnet (YAG) laser in vivo. After opening the pericardium, the 1-mm fiberoptic device was used to create an average of 30 transmyocardial channels per heart at approximate intervals of 0.5 to 1 cm through normal left ventricular myocardium. All dogs tested survived the procedure. The dogs were sacrificed on the first and 60th postoperative days. RESULTS: In the day-1 postoperative group (n = 4), the transmyocardial channels were obliterated at both epicardial and endocardial ends. The channels were totally occupied by necrotic myocytes and did not appear patent under the microscope. In the day-60 postoperative group (n = 6), the epicardial and endocardial scars were identified at each original laser application site. On cross-section, the channels were invaded by fibrous tissue bands extending from the endocardium to the epicardium, without a prominent central passage. Trichrome stained specimens showed that the channels were replaced by collagen fibers, fat tissue and numerous well-developed capillaries or sinusoids in which plenty of red blood cells were found. CONCLUSIONS: We concluded that laser TMR offers no help for acute myocardial ischemia, but results in neovascularization inside the channels by the 60th postoperative day. Angiogenesis induced by laser TMR could possibly play a role in relieving chronic ischemia.

Animals↗
PubMed1999

Mutation analysis of pertussis toxin promoter.

The improving of the expression efficiency of a pertussis toxin (PT) promoter was believed to be a critical issue for the production of PT in acellular vaccine development. In this study, we have isolated a PT promoter region from the genome of a pertussis strain ATCC 9340. Based on the promoter sequence, a series of mutant PT promoters have been generated and subjected to in vitro gel shift analysis and in vivo reporter beta-galactosidase activity study. As compared with the wild type promoter, the mutation of the ribosome binding sequence or -10 element, to the respective consensus sequence derived from strong bacterial promoters, resulted in an enhancement of its interaction with two cellular proteins, and a slightly higher beta-galactosidase activity (1.3 fold). Whereas, the change of either upstream inverse repeats or 20-bp direct repeats to a certain complete repeat significantly promoted the formation of another DNA-protein-complex, and exhibited an 1.8 fold beta-galactosidase activity. These findings would have provided a mutation target for making a more efficient PT-production pertussis strain.

Base Sequence↗
PubMed1999

Adult Citrobacter freundii meningitis: case report.

Citrobacter is a distinct group of Gram-negative bacilli belonging to the Enterobacteriaceae family. Central nervous system (CNS) infections due to Citrobacter are uncommon, though they occur more frequently in neonates and young children. In adults, Citrobacter meningitis is extremely unusual with only 6 cases reported in the literature before 1998. This rare CNS infection has been seen in patients with head trauma, following neurosurgical procedures, and in those who are immunocompromised. Of the patients in the 6 reported cases, only one developed multi-antibiotic resistant Citrobacter CNS infection. Adding to this small number of reported cases, we report an adult case of post-neurosurgical meningitis and subdural empyema caused by multi-antibiotic resistant Citrobacter freundii and also review the literature related to this infection. Antimicrobial therapy with imipenem and third-generation cephalosporins failed to result in cerebrospinal fluid sterilization in our patient. Because of the use of broad-spectrum antibiotics, multi-antibiotic resistant Citrobacter species have developed in this nosocomial CNS infection and now present a therapeutic challenge. Therefore, further clinical studies are needed to determine updated therapeutic modalities for treating this life-threatening infection.

Adult↗
PubMed1998

The relative expression amounts of apterous and its co-factor dLdb/Chip are critical for dorso-ventral compartmentalization in the Drosophila wing.

Dorso-ventral axis formation in the Drosophila wing requires the localized accumulation of the Apterous LIM/homeodomain protein (Ap) in dorsal cells. Here we report that dLdb/Chip encodes a LIM-binding cofactor that controls Ap activity. Both lack and excess of dLdb/Chip function cause the same phenotype as apterous (ap) lack of function; i.e. dorsal to ventral transformations, generation of new wing margins, and wing outgrowths. These results indicate that the normal function of Ap in dorso-ventral compartmentalization requires the correct amount of the DLDB/CHIP co-factor, and suggest that the Ap and DLDB/CHIP proteins form a multimeric functional complex. In support of this model, we show that the dLdb/Chip excess-of-function phenotypes can be rescued by ap overexpression.

Animals↗
PubMed1998

The prognostic factors of adult gram-negative bacillary meningitis.

Seventy-seven patients with Gram-negative bacillary meningitis (GNBM), 57 males and 20 females, aged 17-86 years, were identified at Kaohsiung Chang Gung Memorial Hospital, over an 11-year period. Fifty-four infections were community-acquired, and 23 were nosocomial; 49 were spontaneous and 28 occurred after head surgery or neurosurgery. The organisms most frequently involved were Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter. Rarer pathogens included Citrobacter species, Serratia marcescens, Enterobacter cloacae, and Proteus mirabilis. All patients who did not receive appropriate antibiotic therapy died. The mortality in those treated with appropriate antibiotics was 28%. Other statistically significant prognostic factors included septic shock, initial level of consciousness, hyperosmolar hyperglycemic nonketotic coma, disseminated intravascular coagulation, high cerebrospinal fluid lactate levels and leucocytosis. In the multiple logistic regression analysis, only appropriate antimicrobial therapy and septic shock were strongly associated with mortality even after adjusting for other potentially confounding factors. Despite the high mortality, management can be improved by early diagnosis, early use of appropriate antibiotics, and correction of underlying and associated medical derangement.

Adult↗
PubMed1998

Depressive disorders among the Chinese elderly in a suburban community.

A community survey of depression among the Chinese > or = 65 years in age was performed in a suburban setting. One hundred and eighty-seven individuals comprised the survey group. Among them, 65 (34.8%) were scored > or = 11 on the Chinese version of the Geriatric Depression Scale. Compared with nondepressed individuals, those with depressive disorders were more likely to be older and with poor family support. Forward stepwise logistic regression analysis identified only age as significantly correlating with geriatric depression scores.

Age Factors↗
PubMed1998

Correlations between scores on Chinese versions of long and short forms of the Geriatric Depression Scale among elderly Chinese.

A total of 187 elderly Chinese from the community were interviewed with the Chinese versions of the Geriatric Depression Scale-the long form and the short form. The scores on a proposed new version of the short form were also calculated. Cronbach alpha for the Geriatric Depression Scale-long form was .86. The correlations were significant between scores on the long and short forms (r = .94, p < .05) and between these on the long and new short forms (r = .91, p < .05). Cronbach coefficient alpha for the short form was .77 and for the new short form .81. Results of our study indicated that responding by these elderly persons on both short forms is acceptably internally consistent in comparison with those on the original Geriatric Depression Scale.

Aged↗
PubMed1997

Production and purification of Bordetella pertussis toxin.

Pertussis toxin (PT) is the major protective antigen of acellular pertussis vaccine (aP). We have established an optimal culture condition for the growth of B. pertussis and the production of PT in a laboratory scale fermentor. It was found that when the dissolved oxygen in medium was supplied with pure oxygen instead of air, the yield of PT was dramatically increased (i.e. from 2-3 mg/l using air to 8-10 mg/l using pure oxygen). PT was purified by affinity chromatography using hydroxyapatite and fetuin-sepharose columns. SDS-PAGE analysis and CHO cell clustering test showed that the purified PT was comparable to the reference PT in purity and biological activity. The purified PT could be detoxified by formaldehyde (d-PT). The results of CHO cell clustering neutralization assay and ELISA showed that the antibody induced by d-PT in mice was comparable to that induced by PT contained in a commercial DTaP. These results indicated that the immunogenicity of our d-PT was retained after the purification and detoxification procedures.

Animals↗
PubMed1997

Preparation and characterization of Pertussis toxin subunits.

Pertussis toxin (PT), a typical A-B oligomer exotoxin of Bordetella pertussis, has been demonstrated to be an essential protective antigen for acellular pertussis vaccine against whooping cough. In order to investigate the associated functionality ascribed to its components, we have purified A and B oligomers for the activity study. The A oligomer (S1 subunit) of PT was expressed in E. coli B834 (DE3) harboring expression vector (pET-20b) with the insert of S1 coding region and purified by metal-chelating column. The B oligomer was isolated by a single-step purification procedure. Individually, recombinant S1 and B oligomer exhibited quite distinct biological activities in vivo. S1 subunit induced leukocytosis-promoting (LP) activity, but did not affect mouse body weight-gain. On the contrary, B oligomer reduced mouse body weight-gain but did not reveal LP activity. In vitro, the combination of S1 subunit and B oligomer could enhance the toxic activities as exhibited by native PT and showed an additive toxicity in CHO cell clustering test and hemagglutination assay.

Animals↗
PubMed1997

Klebsiella pneumoniae meningitis: analysis on clinical features of thirty-two adult patients.

BACKGROUND: To assess the clinical features and therapeutic outcomes of adult Klebsiella pneumoniae (KP) meningitis. METHODS: Thirty-two adult patients with KP meningitis were included in this study. Their clinical features, the outcomes with the third generation cephalosporin (moxalactam, cefotaxime, ceftazidime) treatment and prognostic factors were analyzed. RESULTS: These patients' diseases were predominantly community-acquired. Males outnumbered females (3:1). Diabetes mellitus (DM) was the most common underlying disease, followed by other debilitating diseases such as liver cirrhosis, neoplasm and end-stage renal disease (ESRD). Patients with spontaneous meningitis had a more fulminant course with a higher prevalence of bacteremia, shock and death (66%). Metastatic septic abscess was frequent (19%). Among the 21 patients who received initial appropriate antimicrobial therapy (IAAT), 2 took cefotaxime and 1 died; 13 took moxalactam of whom 5 died; and 6 took ceftazidime of whom 3 died. All of the other 11 patients who did not receive IAAT died. CONCLUSIONS: The clinical features of KP meningitis are various and indistinguishable from other form of bacteria meningitis. Most of the patients with KP meningitis are associated with underlying medical problems, such as diabetes mellitus and liver cirrhosis. Many factors, including septic shock, bacteremia, high cerebrospinal fluid lactate concentration, and IAAT, might influence the prognosis. In spite of a high mortality rate, however, IAAT is mandatory to improve the overall survival rate.

Adult↗
PubMed1996

Cause of satisfaction of search effects in contrast studies of the abdomen.

RATIONALE AND OBJECTIVES: Extraintestinal abnormalities visible without contrast material on abdominal radiographs are reported less frequently when contrast examinations are performed. Gaze dwell time was used to determine whether this difference is due to failure by observers to scan plain-film regions of contrast studies or discounting of plain-film abnormalities that were actually scanned. METHODS: Patients were included whose contrast studies had elicited the largest reductions in positive responses compared with their plain-film studies in a previous detection experiment. Gaze of 10 radiologists was studied. RESULTS: Significantly less time was spent gazing at non-contrast regions of contrast examinations than at the corresponding regions of radiographs. Errors with radiographs were based primarily on failures of recognition and decision making, whereas errors with contrast studies were based primarily on faulty scanning. CONCLUSION: Satisfaction of search errors on contrast examinations are caused by reduction in scanning of noncontrast regions.

Contrast Media↗
PubMed1995

Distance from the skin to the cervical epidural space.

BACKGROUND: Cervical epidural blockade provides effective regional analgesia in clinical anesthesia and pain clinics. However, the risk for performing cervical epidural block is higher than lumber epidural anesthesia. We studied the distance from the skin to the cervical epidural space to determine whether there is any relationship between patient age, height, body weight, body mass index (BMI) and the distance from the skin to the epidural space. METHODS: The study included 34 patients who underwent cervical epidural analgesic for orthopedic or plastic surgery. Cervical epidural catheterization was performed at C7-T1 intervertebral space by a midline approach with a 18-G Touhy needle. The depth of the epidural space from the skin was measured by a standard ruler. RESULTS: The distance from the skin to the cervical epidural space at C7-T1 interspace was 4.81 +/- 0.81 cm (mean +/- SD). Linear regression analysis revealed significant correlation between body weight (r2 = 0.53, p < 0.0001), BMI (r2 = 0.58, p < 0.0001) and the depth of the cervical epidural space. CONCLUSIONS: These results indicated that body weight and BMI could be a guideline for identification of epidural space during cervical epidural anesthesia.

Adolescent↗
PubMed1994

Referential coding and attention-shifting accounts of the Simon effect.

Stoffer (1991) and Umiltà and Nicoletti (1992) have proposed an attention-shifting account of the Simon effect. However, Hommel (1993) has presented evidence suggesting that the effect can be explained in terms of referential coding, without invoking attentional shifts. Five experiments are reported here, whose primary purpose is to test implications of the referential-coding account. All of the experiments compared conditions in which a noise stimulus was presented in the position opposite the target stimulus with conditions in which it was not. Contrary to the referential-coding account, (a) the basic Simon effect was larger without a fixation point to serve as a referent than with one; (b) the noise stimulus increased the magnitude of the Simon effect when a fixation point was used, but not when there was no fixation point; and (c) the magnitude of the Simon effect obtained in the presence of a noise stimulus was reduced substantially when the noise and the target (and, if present, the fixation point) were in different colors. The results, although counter to predictions of the referential-coding account, can be accommodated by the attention-shifting account if it is assumed that a fixation point provides an anchor that minimizes attention shifts.

Adult↗
PubMed1994

Satisfaction of search in the detection of plain-film abnormalities in abdominal contrast studies.

RATIONALE AND OBJECTIVES: Satisfaction of search (SOS) occurs when a lesion is "missed" after detecting another lesion in the same radiograph. The authors investigated the SOS effect in abdominal contrast studies. METHODS: The authors measured detection of 23 plain film abnormalities in 43 patients who had plain film and contrast examinations. Each plain-film and contrast study was examined independently by 10 radiologists in two sessions, with receiver operating characteristic (ROC) curve areas estimated with the computer program RSCORE-J (University of Iowa, Iowa City, IA) for each condition. RESULTS: Observers more often missed plain film abnormalities present on contrast studies but also made fewer false-positive (FP) responses. There was no change in ROC area, but decision criteria grew more conservative. CONCLUSIONS: The reduction of detecting plain-film abnormalities in contrast examinations differs from the SOS effect of other imaging studies. The reduction in true-positive (TP) and false-positive (FP) rates suggests that a different cause may underlie these misses.

Contrast Media↗
PubMed1994

Immune responses of young mice to pneumococcal type 9V polysaccharide-tetanus toxoid conjugate.

Pneumococcal type 9V polysaccharide (PS), contained in the current pneumococcal vaccine, induces only a weak antibody response in young children and therefore is not an effective vaccine for young children. To increase its immunogenicity, a conjugate of PS to a protein carrier, tetanus toxoid (TT), was prepared. To quantify the immune response, mouse anti-9V PS immunoglobulin G (IgG) and IgM reference standards were established. Young mice immunized at 2 weeks of age produced IgM antibody in response to 9V PS alone or 9V PS conjugated to TT. However, only the 9V PS-TT conjugate induced an IgG antibody response and an anamnestic effect. Thus, a covalent linkage between TT and 9V PS was required for isotype switching from IgM to IgG. 9V PS-TT adsorbed with aluminum hydroxide adjuvant resulted in a fivefold or greater increase in the IgG antibody level. We also studied the effect of maternal immunization on the immune response of young mice to 9V PS-TT. Maternal immunization before mating or before mating and during gestation primed 2-week-old progeny given two injections of 9V PS-TT to produce more IgM antibody than progeny from unimmunized mothers. The IgG antibody level of neonates at birth was similar to that observed in the mothers and was probably passive antibody. These results indicate that maternal immunization with an optimum dose of a PS-protein conjugate before and/or during pregnancy, followed by immunization of the offspring with the conjugate, could provide young children with an enhanced IgM antibody response to pneumococcal PSs.

Age Factors↗