Strain improvement to enhance the production of recombinant penicillin acylase in high-cell-density Escherichia coli cultures.

Using fed-batch operation for high-cell-density cultivation, efforts are frequently made for optimization of culture parameters, particularly feeding strategy. The current study also emphasized the importance of selecting strains for the production of recombinant proteins in high-cell-density cultures. With Escherichia coli penicillin acylase (PAC) as a target protein, the host/vector system of MDdeltaP7 harboring pTrcKnPAC2902 and pKS12 was designed for optimization of fed-batch cultivation for recombinant protein production. The host, MDdeltaP7, potentially had a high translational and periplasmic processing efficiency for pac expression. On the other hand, the vector, pTrcKnPAC2902, was genetically constructed for pac overexpression. Coexistence of the other vector, pKS12, significantly enhanced PAC production by improving cell physiology and reducing the amount of inclusion body formation upon pac overexpression. An extremely high volumetric PAC activity at 37,500 U/L was obtained with the use of the developed host/vector system under optimum fed-batch culture conditions.

Removal of arsenic from groundwater using point-of-use reverse osmosis and distilling devices.

Ground water in both the northeastern and southwestern coast areas of Taiwan may contain high concentrations of arsenic. Since no central water supply system is available in some of those areas, point-of-use (POU) water purification devices are considered as an option for providing safe drinking water. In this study, removal of arsenic, using two types of POU purification devices, reverse osmosis (RO) systems and distillers, was investigated. Three commercially available RO systems and two distillers were selected to test their removal efficiency of arsenic from synthetic and real ground water. Experimental results of the three RO systems using synthetic ground water showed that only one system had good removal efficiency for arsenic. In subsequent experiments using real ground water with 0.7 mg l(-1) arsenic, only one RO system was able to meet the drinking water standard after producing about 1,000 l of treated water. For the distilling systems, 99% of the arsenic was removed from both synthetic and real groundwater. The arsenic concentrations in the finished water of both distillers were all below the standard for drinking water. Although systems with higher arsenic removal efficiency seemed to have better removal of total dissolved solids (TDS), no correlation could be found after analysis.

The relationship of late potentials to assessment of heart rate variability in post-infarction patients.

In order to investigate the relationship of late potential (LP) to assessment of heart rate variability (HRV) after acute myocardial infarction (AMI), we studied 101 Chinese patients with AMI (10+/-2.4 days) in Taiwan by collecting 24-h ECG from a Holter tape recorder and signal-averaged ECG from a high-resolution ECG cart. Of the 101 patients, 36 patients had LP (LP group) and 65 patients did not (NLP group). The mean heart rate was significantly lower in the LP group than in the NLP group (P<0.05). The LP group had a significantly increased high-frequency (HF) spectral component of HRV compared with the NLP group (P<0.005), but their low-frequency (LF) to HF ratio (LF/HF) was lower (P<0.05). Analysis of the circadian variation of HRV revealed significant difference of morning SDRR (standard deviation of normal RR intervals) compared with noon SDRR (P<0.05 in the LP group, P<0.005 in the NLP group) and evening SDRR (P<0.05 in the LP group, P<0.005 in the NLP group). In the NLP group, morning HF (normalized unit, nu) was 0.258+/-0.098 compared with noon HF (nu) of 0.219+/-0.83 (P<0.05) and evening HF (nu) of 0. 225+/-0.085 (P<0.05). Nine patients died during follow-up from cardiac causes, three (8.3%) in the LP group and six (9.2%) in the NLP group. In post-MI patients, there was higher vagal tone in patients with late potentials compared to those without late potentials. NLP patients had more circadian change in vagal tone compared with LP patients.

Deep neck infections in diabetic patients.

PURPOSE: Deep neck infections may be lethal if life-threatening complications occur, especially in immunocompromised hosts such as diabetic patients. This study was undertaken to better define the clinical features and prognosis of deep neck infections in the diabetic patients with special emphasis on the use of empirical antibiotics and the role and timing of surgical management. PATIENTS AND METHODS: A retrospective analysis of 105 consecutive patients treated at a single institution during a 9-year period was conducted. Of these, 30 patients also presented with diabetes mellitus. RESULTS: Compared with the nondiabetic patients, the unique features of deep neck infections in diabetic patients were as follows: (1) older age, (2) tendency of unclear infection source, (3) tendency to involve multiple spaces, (4) required more aggressive surgical intervention, (5) prolonged hospitalization, and (6) higher complication rate. The differences were statistically significant (P< .05). There were no significant differences in the complete blood count/ differential count positive findings and fever between the 2 groups (P> .05). Bacterial cultures showed that Klebsilla pneumoniae was the most common causative pathogen in diabetic patients. CONCLUSIONS: In deep neck infection patients with diabetes mellitus, the clinical course is more severe and there is a poorer prognosis. Thus, in treating them, we should keep close observation, appropriately control the diabetes, detect the life-threatening complications early, perform aggressive surgical treatment if fluctuation or complication occurs, and take into account the preponderance of K pneumoniae when administering the empirical antibiotics.

Acute and chronic phase platelet aggregability studies in Chinese patients after implantation of a permanent transvenous pacemaker.

It has been suggested that the incidence of thromboembolic events always increases in patients after insertion of a transvenous pacemaker. Blood samples from twenty consecutive patients (fifteen males and five females) before and after pacemaker implantation was retained for platelet aggregability studies which were analyzed separately with ADP, collagen, epinephrine and arachidonic acid. The maximal amplitude of platelet aggregatory curve was detected by an aggregometer. The samples collected the day before pacemaker implantation (day 0) were used as self-control. Day 1 and day 3 after pacemaker implantation were defined as the acute phase, while day 30 was defined as the chronic phase. The maximal amplitude of platelet aggregatory curve was observed to be lowest on day 1 and then return to normal on day 3 and day 30. The results of platelet aggregability, however, showed no significant difference (P>0.05) between self-control and post-implantation samples. In conclusion, there was no significant change in platelet aggregability for either acute or chronic phases after pacemaker implantation. Antiplatelet medications may not be necessary for the prevention of thromboembolic events after the implantation of a pacemaker.

Esophageal PP intervals for analysis of short-term heart rate variability in patients with atrioventricular block before and after insertion of a temporary ventricular inhibited pacemaker.

Heart rate variability (HRV) analysis is a useful method for assessment of the activities of autonomic nervous system. The RR intervals in ECG is measured for this purpose. However, RR intervals are not suitable for HRV analysis in atrioventricular block (AV) block patients with ventricular inhibited (VVI) pacemaker, as the intervals will be fixed by the ventricular pacemaker. Thus we used an esophageal lead to detect PP intervals for analysis of HRV. The aim of this study was to evaluate the short-term HRV by using an esophageal electrode to detect the atrial signal and PP intervals in AV block patients. Fifteen AV block patients before and after temporary VVI pacemaker and 15 subjects with normal AV conduction (control group) were enrolled in this study. The atrial signals from esophageal lead, ECG and intraatrial lead were recorded. The duration was 10 min. We compared correlation coefficient of PP intervals from different leads in AV block patients and the control group. We also compared the PP interval's variability parameters between the control group and AV block patients, before and after insertion of a temporary ventricular inhibited pacemaker. The esophageal PP intervals were excellently correlated with intraatrial AA intervals (r=0.98+/-0.01). The HRV using esophageal PP intervals with time domain demonstrated a significant decrease in patients with AV block (standard deviation of all PP intervals (SDNN) (s)=0.022+/-0.014; percentage difference between adjacent PP intervals that are greater than 50 ms (pNN-50) (%)=0.052+/-0.038; square root of the mean of squares of differences between duration of neighboring PP intervals (r-MSDD) (s)=0.322+/-0.082) but this returned to normal after insertion of a temporary ventricular inhibited pacemaker (SDNN (s)=0.035+/-0.009; pNN-50 (%)=2.540+/-1.682; r-MSDD (s)=0.542+/-0.190). However, the ratio of low frequency/high frequency (LF/HF) still increased (LF/HF=4.120+/-1.802). The result of this short-term HRV analysis suggested that withdrawal of vagal tone or increased sympathetic activity in AV block patients compared with the control group. This appearance was normalized after insertion of a temporary VVI pacemaker. however, abnormal sympathovagal balance still remained.

Predisposing factors of life-threatening deep neck infection: logistic regression analysis of 214 cases.

OBJECTIVE: In the era of antibiotics, most deep neck infections can be cured by conservative treatment, but some still result in life-threatening complications. In this study, we discuss whether or not there are predisposing factors of complicated deep neck infection. DESIGN: A retrospective chart review of patients presenting between 1988 and 1996 was conducted. METHOD: Among 214 deep neck infection patients, 18 cases resulted in lethal complications. We used the "dummy" variable with logistic regression as the statistical analysis method. RESULTS: Patients with an underlying disease, neck swelling, and delay time had a positive correlation that was statistically significance (p < .05). Patients who were older, male, with complete blood count/differential count-positive finding and fever had positive correlation, but this was not statistically significant (p > .05). CONCLUSION: Although complicated deep neck infection is a rapidly progressive disease with a high mortality, we can not thoroughly predict the prognosis or avoid it happening completely. But, if we can detect and pay more attention to the high-risk group of patients with use of aggressive therapy, the incidence of complicated deep neck infection may be reduced.

Right ventricular electrode lead implantation via a persistent left superior vena cava. An improved technique.

Persistent left superior vena cava occurs in approximately 0.5% of the population. This may complicate pacemaker implantation by making lead insertion difficult and causing lead instability through the left cephalic vein and the subclavian vein approach. We used a wide loop technique in the right atrium and successfully advanced the lead in the right ventricle apex. A persistent left superior vena cava does not preclude successful lead placement.

Heart rate variability in patients with atrioventricular block.

BACKGROUND: Heart rate variability (HRV) analysis has been an established method for assessment of the activities of autonomic nervous system. Conventionally, the RR intervals from the surface electrocardiogram (ECG) are used for HRV analysis, however, analysis of the RR intervals may not be suitable in patients with atrioventricular (AV) node dysfunction, particularly in patients with certain degree of AV block. We used an esophageal electrode to detect PP intervals for HRV analysis in these patients. METHODS: Seven AV block patients and 13 subjects with normal AV conduction (control group) were enrolled in this study. The signals from esophageal lead, surface lead and intraatrial lead were recorded. Correlation coefficient of heart beat intervals from different leads was analyzed. Then we compared the HRV parameter recorded by esophageal lead between AV block patients and the control group. RESULTS: The AA intervals in intraatrial ECG and the PP intervals in surface ECG were poorly correlated (r = 0.489) in the AV block patients. However, intraatrial ECG was correlated well with esophageal ECG (r = 0.968). HRV with time domain decreased significantly in patients with AV block. The standard deviation of NN intervals (SDNN), pNN-50 and r-MSSD in the control group and the AV block patients were 0.035 +/- 0.006 vs. 0.021 +/- 0.016 seconds (p = 0.002), 3.210 +/- 3.120 vs. 0.050 +/- 0.040% (p = 0.027) and 0.577 +/- 0.181 vs. 0.318 +/- 0.084 seconds (p = 0.009), respectively. CONCLUSIONS: The esophageal lead recording is a non-invasive, easy and safe method to detect HRV of AV block patients whose vagal activity is abnormal.

Transaxillary endoscopic sympathectomy--a report of experience in 150 patients with palmar hyperhidrosis.

We report our 1-year experience with transaxillary endoscopic sympathectomy in 150 patients with palmar hyperhidrosis (PH). The double-puncture technique of video laparoscopy was used in a transaxillary approach to perform the sympathectomy by either electrocautery (EC; 93.3%) or electroresection (ER; 7.7%). The procedure was successfully completed in 299 operated limbs and required conversion to open surgery in 1 operated limb because of extensive pleural adhesions. The mean operative time of EC was significantly less than that of ER. In a total of 29 procedures, there were three technical complications. Most patients (92.7%) were discharged after an overnight hospital stay. On the seventh postoperative day, the cure rate was 99.3%. During the mean follow-up period of 200.1 days, there was no recurrence in 130 patients. Apparent compensatory hyperhidrosis occurred in 28 patients (21.5%). In conclusion, transaxillary endoscopic sympathectomy offers a simple and effective treatment to patients with PH, resulting in a shorter hospital stay and convalescent period.

Computed tomographic finding in adenomyomatosis of the gallbladder.

We report on an uncommon case of symptomatic generalized adenomyomatosis of the gallbladder. It was initially suspected by ultrasonography and further confirmed by computed tomography (CT). A postcontrast CT scan at the level of the gallbladder body demonstrated the characteristic rosary sign. The rosary sign is formed by the enhanced proliferative mucosal epithelium with the intramural diverticula surrounded by the unenhanced hypertrophied muscle coat of the gallbladder. Similar CT scans were obtained sequentially in the caudal direction. These CT scan findings indicated generalized adenomyomatosis of the gallbladder. The patient received a cholecystectomy. The pathologic report showed specific changes of adenomyomatosis corresponding to the findings on the CT scan. Generalized adenomyomatosis of the gallbladder, therefore, can be accurately diagnosed by CT.

Mutagenicity and polycyclic aromatic hydrocarbons analysis of airborne particulate matters from Taipei City.

The mutagenic activity of dichloromethane extracts of 147 air particulate samples collected from 8 stations during December 1986-June 1987 in Taipei city was consistently higher in S. typhimurium strain TA 98 than in strain TA 100 in the presence of S9 mixture. Among the 8 stations, Nan Kang Police Station, Fu Hsing Elementary School, and Chung Hsing University which were located in the industrial district, downtown area, and heavy traffic zone, respectively, had significantly higher levels of PAHs than the other stations. In contrast, the levels of PAHs were much lower in the suburban station, near Pei Tou Elementary School. However, PAH contents of the air particulate samples collected from these stations did not show good correlation with their mutagenicity. The air particulates collected at some stations on Sunday when the traffic changed from heavy to light showed lower mutagenicity and PAH contents as compared with the other weekdays at the same stations. On the contrary, the samples collected at Pei Tou station in a suburban area where the traffic changed from light to heavy on Sunday showed higher mutagenicity and PAH contents. The monthly average of PAHs of air particulate samples collected over a 7-month period from 8 stations in Taipei city was lower than the average in 1980. Moreover, when compared with other countries, such as U.S.A., the Netherlands, West Germany, Italy, Norway, and Japan, the levels of PAHs and mutagenicity of air particulate matters in Taipei city were similar or slightly lower. The mutagenicity and contents of PAHs of air particulates collected from burnt ABS were significantly higher than those of burnt PVC. One sample PT-6-3 was collected while a nearby garbage collection area was on fire. The mutagenicity of that sample increased 3 to 16 fold and contained an 11 to 33 times higher content of the six PAHs (BaP, BeP, BbF, BaA, Chr, and DbA) as compared with the other samples collected at the same location at a different time. The higher mutagenicity and PAH contents of that sample might be due to the pollution of the air from combustion of the garbage containing products made of ABS.